diagnostic imaging and radiology

7/25/2019 Diagnostic Imaging and Radiology

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Diagnostic Imaging and Radiology

A 42 year old female presents to her physicians office with complaints of headache and blurred vision. Her symptoms have been occurring over

the last 3 weeks. She has no other complaints. Past medical history reveals that she had a breast cancer removed via lumpectomy 1 year ago, but

did not require chemotherapy or radiation. Family history is positive for polycystic kidney disease in a paternal grandfather and neurofibromatosis in

a maternal grandmother. Physical examination is only remarkable for left peripheral visual field defects. The patient is sent to radiology for a CT

scan of her brain for further evaluation. The study is performed with the administration of intravenous contrast and an image from the scan is shown

here.

Which of the following conditions would you not include in your differential diagnosis for this patient?

1) Craniopharyngioma2) Epidermoid3) Meningioma4) Berry aneurysm5) Metastatic lesion

The correct answer is choice B.


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Epidermoid (choice B) is the only condition listed that should not be included in the differential diagnosis for this patient.

The contrast enhanced CT scan of the suprasellar region demonstrates an approximately 2.5 cm extra-axial, densely enhancing, homogeneous,rounded mass lesion in the left middle cranial fossa just above the medial aspect of the right tentorium, exerting mild mass effect on the inferioraspect of the left frontal lobe.

Although epidermoid tumors can occur extra-axially in this location, they characteristically are of very low density and do not enhance to any extentexcept for perhaps mild ring-enhancement. Hence this choice is an incorrect answer.

The strongest candidates in this differential diagnosis are meningioma (choice C), Berry aneurysm (choice D), and metastatic lesion. Not only isthis lesion radigraphically very similar in appearance to each of these conditions, but the patients history should alert you that she has potentialreason to have each of these conditions. Her history of breast cancer should make you suspicious of a metastatic lesion. Her positive family history

of polycystic kidney disease (PCKD) and neurofibromatosis should alert you to the possibilities of a Berry aneurysm and a meningiomarespectively, as these conditions have high associations as listed.

Meningioma is a benign tumor of the meninges that frequently occurs in the suprasellar region. It is the most common extra-axial tumor in thecranium and it intensely enhances after the administration of intravenous contrast. There is a known association with neurofibromatosis.Meningiomas may appear dense on noncontrast CT scans due to the possibility of psammomatous calcifications within. They typically abut ameningeal surface. They may cause hyperostosis of adjacent bone and only very rarely may cause peritumoral edema. Meningiomas tend to beeasily removed at surgery. The tumor presented in this case is in fact a meningioma.

Berry aneurysm (choice D) is a congenital condition that has a high association with adult PCKD. They are located at the circle of Willis. Theseaneurysms are very susceptible to rupture, and lead to the classic history of the worst headache of my life. When they rupture they cause asubarachnoid hemorrhage. On contrast enhanced CT scan they enhance intensely and are found in the region of the circle of Willis.

Metastatic lesions (choice E) to the suprasellar region tend to be from primary tumors of the lung, breast, kidney, and GI tract. These lesions can be


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smooth or irregular in shape, usually enhance homogeneously, and may destroy adjacent bone.

Craniopharyngioma (choice A), a tumor from the remnant of Rathkes pouch more commonly seen in children, is typically a mixeddensity lesionthat may contain cystic and solid portions, the solid portion of which will enhance variably. They are commonly located in the suprasellar region andmay contain dense calcifications.

A 43 year old male patient comes into the emergency room with complaints of dyspnea, chest pain, fatigue, lower extremity edema, and abdominal

distension and discomfort. He says that these symptoms have all been coming on gradually over the last few years and that he had not sought

medical attention because he did not have health insurance until now. On physical examination the patient appears quite thin, has a blood pressure

of 95 over 55, sinus tachycardia, jugular venous distension, and hepatomegaly with probable ascites. The ER physician sends the patient to

radiology for a chest X-ray which is as shown and you are interpreting it.

Which of the following conditions is a possible etiology of this finding?

1) Tuberculosis

2) Previous radiation therapy to the mediastinum


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3) Uremia

4) Rheumatoid disease

5) All of the above

The correct answer is choice E.

The significant finding on the chest X-ray are thickening of the pericardium best seen on the lateral view, small left atrium on the lateral view,straightening of the left cardiac border, normal sized heart, unremarkable pulmonary vascularity, and a small right pleural effusion. These findingsin combination with the clinical presentation are strongly suggestive of a constrictive pericarditits. Other potential chest X-ray findings in patientswith constrictive pericarditis are pericardial calcification, straightening of the right cardiac border, and enlargement of the SVC, IVC and azygousvein.

All of the above (choice E) listed diagnoses can cause constrictive pericarditis.

Tuberculous pericarditis (choice A) is not as common an etiology of constrictive pericarditis now as it was in years past when it was the mostfrequent cause. In such cases, there would frequently be other signs of tuberculosis infection in the chest such as apical lung disease andmediastinal lymphadenopathy.

Previous radiation to the mediastinum (choice B) may also produce a constrictive pericarditis, particularly as may be the case with high doseradiation to the mediastinum used for Hodgkins disease. Uremic patients (choice C) on prolonged hemodialysis are at high risk for constrictivepericarditis. Constrictive pericarditis in rheumatoid disease (choice D) is relatively rare, but can occur. Clinically evident pericarditis is only presentin about 2% of rheumatoid patients, and only about 10-20% of those would be classified as constrictive.

A 62 year old male presents to his physician with complaints of fatigue, malaise, decreased appetite, weight loss, and vague abdominal pain over

the course of the last 3 months. Past medical history is positive for an episode of hepatitis B 15 years previously. Review of systems reveals that

the patient has been having 3-4 drinks of Scotch whiskey per day for many years. Physical examination is remarkable for slight scleral icterus and


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fullness in the right upper quadrant. Laboratory findings confirm a high bilirubin level and show elevated liver function tests as well. The patient is

sent to radiology for an abdominal CT scan, which is performed with intravenous contrast. You are interpreting the study, an image of which is

shown here.

Based on the findings of this CT scan, which of the following conditions would you include in your differential diagnosis for this case?

1) Hepatocellular carcinoma2) Metastatic melanoma3) Cavernous hemangioma4) Focal nodular hyperplasia5) All of the above


The CT scan shows a large, round mass in the right lobe of the liver which is enhancing peripherally and toward the center. All of the above choices(choice E) can manifest with such an appearance on abdominal CT scan and should be included in the differential diagnosis for this CTappearance. Arterial phase imaging with spiral CT scanning (not shown here) can help to narrow down this differential diagnosis even further as


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explained in the following paragraphs.

Hepatocellular carcinoma (choice A) is responsible for 90% of all primary liver malignancies. It tends to present in the 6th to 7th decades of life, andhas a male to female predominance of 2 :1. There is an increased incidence of hepatoma in patients with cirrhosis, hepatitis B or C, andhemochromatosis. Patients may present with RUQ pain, fever, weight loss, malaise, hepatomegaly, and ascites. Laboratory findings usuallydemonstrate elevated alpha-fetoprotien levels and elevated LFTs. Arterial phase enhancement pattern on spiral CT scan frequently showsabnormal internal vessels or a variegated pattern in hepatocellular carcinoma.

Metastatic melanoma (choice B) and other vascular metastatic lesions such as carcionoid, renal cell carcinoma, thyroid carcinoma can manifest asa peripherally enhancing intrahepatic mass on CT scan. These lesions frequently demonstrate complete ring enhancement during the arterialphase on spiral CT scanning.

Cavernous hemangioma (choice C) likewise can manifest as a peripherally enhancing intrahepatic mass on CT scan with progression of

enhancement centrally over time. It is the most common benign liver tumor of adults and affects females more than males. There may beassociated hemangiomas in other organs, and there is an association with Osler-Weber-Rendu disease. These tumors are generally asymptomatic,but may present with hepatomegaly and abdominal discomfort. Arterial phase enhancement pattern on spiral CT scan frequently shows peripheralpuddling in cavernous hemangiomas.

Focal nodular hyperplasia (choice D) is a manifestion of a reparative process in the liver as a response to injury. This lesion is generallyasymptomatic, but may present with vague abdominal pain, usually in the 3rd to 5th decades of life. It is more common in females than males andhas an increased incidence in women who use oral contraceptives. There may be a central stellate appearing scar see in 15% of cases. Arterialphase enhancement pattern on spiral CT scan frequently shows a diffuse uniform enhancement pattern in cases of focal nodular hyperplasia.

A 13 year old male presents to his pediatricians office with complaints of pain in his right lower leg, just below the knee.His mother adds that the

boy has also had a low grade fever off and on for awhile and that he seems less active than normal. Physical examination reveals a temperature of

99.8 and moderate tenderness in the region of the proximal diaphysis of the right tibia. The patient is sent to the department of radiology for X-rays

of his right tibia/fibula. An image from that study is shown. Because of the patients age, the 2 most likely bone tumors that you include in your

differential diagnosis are osteosarcoma and Ewings sarcoma.


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With regard to osteosarcoma and Ewings sarcoma, which of the following statements isnottrue?

1) Osteosarcoma is the most common malignant tumor of bone in childhood2) Osteosarcoma involves the long bones more frequently than does Ewings sarcoma

3) Osteosarcoma frequently demonstrates the classic onion-skin appearance of periosteal bone formation4) Ewings sarcoma is frequently found in the bones of the pelvis5) Ewings sarcoma generally demonstrates more bony lysis than sclerosis as a radiographic finding

The correct answer is choice C.


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Ewings sarcoma frequently demonstrates the classic onion-skin appearance of periosteal bone formation, therefore choice C is an incorrectstatement.

Osteosarcoma is a malignant bone tumor that arises from connective tissue and is the most common primary malignancy of bone in childhood(choice A). It is more common in males than females with a ratio of 3:2, and maximum incidence in the 2nd decade of life. Osteosarcoma involvesthe long bones in 80-90% of cases (choice B), frequently in the lower extremities, particularly around the knee joint. It is usually metaphyseal inlocation and may extend into the epiphysis. It tends to penetrate the bony cortex and elevate the periosteum, and have a soft tissue massassociated with it, possibly containing calcifications. Classically seen is a mixture of bone destruction and bone sclerosis on plain films withspiculation present that radiates perpendicular to the bony cortex. A classic Codmans triangle may also be seen in advanced cases.

Ewings sarcoma is a malignant round cell tumor which is more rare and accounts for approximately 10% of primary malignant bone tumors. It moreoften occurs in the 2nd decade of life, but may also present well into the 3rd decade, and has a slight predilection for males over females. It mayoccur in the long or flat bones with approximately equal distribution between the two (choice B). When in long bones, it may be located in either thediaphyseal or metaphyseal region, and when in flat bones, it is frequently found in the pelvis (choice D). Radiologic features include bony lysis with

minimal reactive bone formation and sclerosis. When this tumor reaches the periosteal surface, it stimulates periosteal bone formation which maybe laminated and show the classic onion-skin appearance associated with Ewings sarcoma (choice C). Spiculation may also be present.

A 40 year old woman comes in for her first screening mammogram, which you are now interpreting. You make the following three conclusions on

the mammogram: 8 mm calcified fibroadenoma, scattered vascular calcifications, and a right axillary lymph node that is 9 mm along its longest axis.

What BI-RADS classification should you assign this patient in your impression?

1) BI-RAD 02) BI-RAD 13) BI-RAD 24) BI-RAD 35) BI-RAD 4


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BI-RADS is an acronym that stands for Breast Imaging-Reporting and Data System. This system serves to standardize mammography reporting byputting findings into categories which suggest different guidelines for follow-up. There are seven BI-RADS categories as follows:

BI-RAD 0 - Need additional imaging evaluation - Additional imaging needed before a category can be assigned.

BI-RAD 1Negative - Continue annual screening mammograms for women over age 40.

BI-RAD 2 - Benign finding - Continue annual screening mammograms for women over age 40.

BI-RAD 3 - Probably benign findingRecommend a 6-month follow-up mammogram for further evaluation.

BI-RAD 4 - Suspicious abnormality presentConsider biopsy.

BI-RAD 5 - Highly suggestive of malignancyBiopsy required.

BI-RAD 6 - Known biopsy-proven malignancy - Biopsy has confirmed presence of cancer before treatment hasbegun.


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The findings of an 8mm calcified fibroadenoma, scattered vascular calcifications, and a right axillary lymph node that is 9 mm along its longest axisare all benign findings that do not require anymore than routine follow-up. Therefore, this mammogram interpretation is assigned the classificationof BI-RADS 2 (choice C).

A 48 year old heavyset woman comes into the emergency room complaining of severe right upper quadrant (RUQ) postprandial pain. The ER

physician establishes that she has a fever of 102 degrees, a positive Murphys sign, and an elevated white blood cell count of 14,000 with a left

shift. She is sent to the radiology department to have a RUQ ultrasound. The ultrasound technologist asks you to come into the examination roomand look at the real-time ultrasound with her because she is having trouble identifying the gallbladder. You go in and scan the patient and find that

there are very dense linear echoes in the region of the gallbladder fossa with limited through transmission.

Which of the following diagnoses do you suspect at this point?

1) Acalculous cholecystitis2) Chronic cholecystitis3) Gallstone ileus4) Emphysematous cholecystitis

5) Porcelain gallbladder

The correct answer is choice D.

The very dense linear echoes in the region of the gallbladder fossa with limited through transmission in a patient with signs and symptoms of acutecholecystitis should lead you to suspect that the patient may have emphysematous cholecystitis (choice D). Air present in the gallbladder wall willnot transmit ultrasound waves and will read as very dense linear echoes with limited through transmission.

Emphysematous cholecystitis may also be referred to as gangrenous cholecystitis. It is usually associated with gas-forming organisms such asclostridium perfringens, clostridium Welchii, and E. coli. The mortality rate for this condition is approximately 15%.

Porcelain gallbladder (choice E) due to calcium incrustation of the gallbladder wall can also cause dense linear echoes with limited through


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transmission when scanning the gallbladder wall, but, patients with porcelain gallbladder are usually asymptomatic and would not present withsymptoms and signs of acute cholecystitis.

Gallstone ileus (choice C) is due to the erosion of a gallstone through the gallbladder wall into the GI tract subsequently causing an obstruction,frequently at the level of the ileo-cecal valve. These patients may have gas in the biliary tree and gallbladder, but would not have gas within thegallbladder wall.

Acalculous cholecystitis (choice A) and chronic cholecystitis (choice B) would not have the show dense linear echoes with limited throughtransmission when scanning the gallbladder wall, rather, visualization of the gallbladder with ultrasound would be possible.

You are the radiology resident assigned to the high magnetic field MRI scanner for the day. You begin your day by reviewing all the charts ofscheduled patients for the day, reviewing patient history and reason for performing the MRI scan so that you can tailor each examinationappropriately. In your review of the charts, you find the following information on four of the scheduled patients.

In which of these four patients would you notproceed with the MRI scan?1) A 38 year old male that weighs 400 lbs2) A 28 year old woman who is 6 months pregnant that will not require the administration of IV contrast material3) A 52 year old male that had a left total hip replacement in 20094) A 55 year old female with dental implants5) A 75 year old male with an insulin pump


An insulin pump (choice E) is a contraindication to performing an MRI because it contains magnetic components.

Other absolute contraindications to MRI are magnetically activated cardiac pacemakers, defibrillators, neurostimulators, cochlear implants, as wellas metallic fragments within the eye, ferromagnetic intracranial aneurysm clips, nongraphite spinal cord tongs, and Swan-Ganz catheters. Patientsweighing over 425 lbs exceed the weight limit of most MRI tables posing a risk to the patient and MRI equipment; scanning in such instances


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should be avoided.

Relative contraindications to MRI include implanted lead wires, prosthetic heart valves (unless dehiscence is suspected, then it would becontraindicated), body hemostatic clips, tattoos and certain makeup, first trimester of pregnancy as long term effects on the fetus are not wellknown.

Choice Aa 400 lb patient could proceed to have an MRI as this weight is below the maximum weight limit for the MRI table. Choice Ba patientwho is in her 6th month of pregnancy could proceed with an MRI as the concern in pregnancy for safety of the fetus is only in the first trimester, butintravenous contrast during MRI is generally avoided for the entire pregancy as its long-term effects on the fetus are not well known. Choices C andDdental implants and joint prostheses are not contraindications to MRI scanning, although they may cause artifacts on images obtained.

A 22 month old boy is brought to the emergency room by his father who states that the boy suddenly developed difficulty breathing, fever, and is

making a funny sound when he breathes in. He also states that the boy was found earlier in the day having gotten into a bowl of peanuts

inadvertently left on the coffee table and he wonders if the boy might have aspirated a peanut. Physical examination reveals that the boy is holding

his head forward, is in obvious respiratory distress, and has inspiratory stridor. He also has a temperature of 102. The patient is immediately sent to

radiology for AP and lateral films of his neck, the lateral of which is shown here.

What is your diagnosis in this patient?


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1) Croup2) Peanut lodged in upper trachea3) Bronchiolitis4) Epiglottitis5) Retropharyngeal abscess



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The lateral X-ray of the neck shows a markedly enlarged epiglottis and aryepiglottic folds, consistent with the diagnosis of epiglottitis (choice D).

Epiglottitis is a life-threatening infection due to Hemophilus influenzae (sometimes pneumococcus or streptococcus group A) which causessignificant edema of the epiglottis and aryepiglottic folds. The most common ages of onset are 3-6 years of age. Symptoms are abrupt onset ofrespiratory distress with inspiratory stridor and dysphagia. Diagnosis is readily made on a lateral neck X-ray which will show enlargement of theepiglottis and aryepiglottic folds. The epiglottis can be readily identified as it is projected atop the hyoid bone on the lateral view, and thearyepiglottic fold extending posterior and inferior to it. Note should be made that in suspected cases of epiglottitis, the lateral neck image should beobtained with the patient in the upright position, as supine positioning may hasten obstruction of the airway. The life-threatening danger of thiscondition is due to the risk of closure of the airway by the enlarged, edematous epiglottis and aryepiglottic folds.

Croup (choice A) is an acute laryngotracheobronchitis of viral origin. In this condition, the critical area of airway narrowing is in the subglottic region.Peak incidence of this condition is 6 months2 years of age. Croup is usually associated with a few day history of respiratory tract infectioussymptoms and a brassy cough. AP neck films show the classic steeple sign which represents the subglottic edema and results in a steeple-likeappearance of the subglottic airway. An example of a PA radiograph of croup with the classic steeple sign is shown here:


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It is important to make the distinction between croup and epiglottitis, and in croup, the epiglottis is not enlarged, therefore this choice is incorrect.

A peanut lodged in the upper trachea (choice B) may show as a soft tissue filling defect in the tracheal airway, or may not show up on a plain X-rayat all. Although the possibility of peanut aspiration was raised in this patient, and symptoms of respiratory distress and stridor may occur, therewould generally not be the presence of fever and the epiglottis would definitely not be enlarged on lateral neck X-ray, hence this choice is incorrect.

Bronhciolitis (choice C) is an incorrect choice as it is a viral inflammation (commonly due to respiratory syncytial virusRSV) of the lower airwaysin infants less than 1 year of age which causes air-trapping in the lungs. Radiographic findings include hyperinflation on chest X-ray and increase inbronchiolar markings.


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Retropharyngeal abscess (choice E) may occur in infants secondary to a nasopharyngeal infection, or secondary to a penetrating injury, such asone incurred by falling on a Popsicle stick which pierces the retropharyngeal mucosa. Radiographic signs include thickening of the retropharyngealspace seen on lateral neck film with anterior displacement of the upper airway. These signs are not seen in this case and therefore this choice isincorrect.

A 3 year old girl is brought to her pediatricians office by her mother for a routine visit. On physical examination, he patients blood pressure is

elevated at 140/90 and the pediatrician detects a mass palpable in the patients right upper quadrant. Upon further questioning of the patientsmother, it is revealed that the child has intermittently complained of stomach aches. The patient is sent to radiology for evaluation of the

abdominal mass by ultrasound, to be followed by abdominal CT scan as necessary. You are interpreting the abdominal CT scan which has been

performed with the administration of intravenous contrast. An image from that CT scan is shown.

Of the following choices, which is the most likely diagnosis in this patient?


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1) Right-sided hydrohephrosis2) Neuroblastoma3) Wilms tumor4) Renal cell carcinoma5) Angiomyolipoma


The abdominal CT scan shows an extremely large, heterogeneously enhancing mass of the right kidney. The determination that the mass isintrarenal is made by the visible splaying of the nephrogram by the mass posteriorly. This is an important differential diagnostic point in this case.

Wilms tumor (choice C) is the most common primary malignant renal tumor of childhood. It occurs in approximately 1:10,000 individuals, with apeak age of presentation at 3-4 years old. Discovery of Wilms tumor is most often made after detection of a palpable mass on physical

examination, or possibly after coincidental trauma and imaging. Hypertension may be present in up to 50% of cases. Wilms tumor arisesembryologically from cells of the metanephros. Metastases may occur to the lungs, liver, and regional lymph nodes. Occasionally, it may extendinto the renal vein and IVC. It can also be bilateral in a small percentage of cases. CT generally demonstrates a large, round, heterogeneous,intrarenal mass with peripheral enhancement and a lower density center due to necrosis. There may be a thick pseudocapsule present andcalcifications within the mass. Treatment is via nephrectomy and some potential combination of chemotherapy and radiation. Cure rates arereported as high as 90%.

Right-sided hydronephrosis (choice A) is not an appropriate choice in this case as it would not have the appearance of a solid intrarenal mass.

Neuroblastoma (choice B), although another common abdominal mass in children, is an extrarenal mass, generally originating in the adrenal gland,and would not demonstrate the intrarenal appearance of the mass as in this case, and is therefore incorrect.

Renal cell carcinoma (choice D), although may have a similar CT appearance, is primarily a disease of adulthood, and exceedingly rare in children,


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therefore an incorrect choice.

Angiomyolipoma (choice E) is a benign tumor of adulthood, which is also extrarenal, frequently originating in the adrenal gland, and thereforeincorrect as well.

You are the radiology resident assigned to the CT scanner for the day. You begin your day by reviewing all the charts of scheduled patients for theday, reviewing patient history and reason for performing the CT scan so that you can tailor each scan appropriately. In your review of the charts,

you determine that the following four patients would all require the administration of IV contrast material during the CT scan.

In which of these four patients would you proceed with the CT scan?

1) 43 year old male that weighs more than 425 lbs2) 32 year old woman that is pregnant3) 72 year old male with chronic renal failure on dialysis4) 49 year old woman with a past history of an IV contrast reaction who has not been pretreated for the examination5) None of above; each patient listed has a contraindication to having a CT scan performed


A patient who has chronic renal failure and is on dialysis (choice C) may receive IV contrast and have a CT scan performed as the IV contrast willbe cleared during the patient's dialysis.

Pregnancy (choice B) is an absolute contraindication to CT scan as the modality employs radiation which can pose a significant risk to the fetus fordeveloping congenital anomalies.

Other relative contraindications include patient weight greater than 425 lbs (choice A) as such weight exceeds that which can be safely supportedby the CT table and therefore would pose a risk to the patient as well as the CT equipment, and a patient history of contrast reaction unless thepatient has been pretreated with corticosteroids (choice D). Other relative contraindications include renal insufficiency and hyperthyroidism/goiter if


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intravenous contrast is to be administered during the CT scan.

Choice Enone of the above, is incorrect as choice C is a correct answer.

A one day old male newborn in the hospital nursery is irritable and has vomited most of his first feeding. After the newborns second feeding, he

again is irritable and vomits. The pediatrician covering orders an abdominal X-ray which you are now interpreting. The film shows a classic double

bubble sign.

Which of the following conditions would you not include in your differential diagnosis for this case?

1) Annular pancreas2) Duodenal atresia3) Midgut volvulus with axis at ligament of Treitz4) Hypertrophic pyloric stenosis5) Preduodenal positioning of portal vein


Hypertrophic pyloric stenosis may also cause GI obstruction in the newborn, but the classic finding on X-ray in this condition is the single bubblesign, as a result of an enlarged gas containing stomach and the inability of the gas to pass through the pylorus into the duodenum.

The double bubble sign is indicative of duodenal obstruction, either intrinsic or extrinsic. The two bubbles represent a distended gas-filled stomachand duodenum, with lack of gas distal to the duodenum.

Examples of intrinsic obstruction of the duodenum are: duodenal atresia (choice B), duodenal stenosis, and duodenal webs. Examples of extrinsicduodenal obstruction are: annular pancreas (choice A), midgut volvulus with axis at ligament of Treitz (choice C), and preduodenal positioning of


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the portal vein (choice E).

The double bubble sign may also be seen on ultrasound of the abdomen in these conditions.

A 28 year old woman comes into the emergency room with lower abdominal pain and vaginal bleeding, with the pain being significantly worse than

that with her normal menses. Upon questioning by the ER resident, the patient reveals that her last period was actually 2 months prior. Physicaland pelvic examinations reveal a slightly enlarged uterus with pain elicited upon manipulation of the cervix. There is a slight suggestion of a left

adnexal mass. Urine pregnancy test is positive, serum beta-hCG is 2,000 and transabdominal ultrasound does not reveal an intrauterine

gestational sac. The ER resident suspects that the patient has an ectopic pregnancy and you, the radiology resident, are called to the ER to

perform a transvaginal ultrasound for further evaluation. An image from that study is shown.

Of the following transvaginal ultrasound findings that may be seen in ectopic pregnancy, which finding is the most diagnostic?


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1) Fluid in the pouch of Douglas2) Ectopic mass3) Ectopic mass and fluid in the pouch of Douglas4) Absence of intrauterine pregnancy5) Ectopic cardiac activity


The most specific findings for ectopic pregnancy on transvaginal ultrasound in order of specificity are ectopic cardiac activity (choice E), followed byectopic gestational sac, ectopic mass and fluid in the pouch of Douglas (choice C), fluid in the pouch of Douglas (choice A), ectopic mass (choice


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B), and absence of intrauterine pregnancy (choice D).

Ectopic pregnancy occurs in up to 1.9% of pregnancies and ruptured ectopic pregnancies are a life threatening condition, the incidence of whichhas diminished with the advent of transvaginal ultrasound leading to more rapid diagnosis and treatment.

A 29 year old healthy male athlete who has sustained an injury to his left knee is sent by his orthopedist to the radiology department for an MRI of

the left knee which you are interpreting. You determine that the knee ligaments and cartilages are normal, and that there is no evidence of

traumatic injury to the left knee except for the presence of a small joint effusion. You do however make the finding of a very well defined 3 cm

eccentric lesion of the tibial diaphysis that is low intensity on T1 weighted images and low intensity on T2 weighted images. Plain X-rays of the

patients left knee are unavailable for viewing at this time.

Of the following benign lesions of bone, which one would demonstrate low signal intensity on T1 weighted images and low signal intensity on T2

weighted images?

1) Simple bone cyst

2) Benign osteoblastoma3) Enchondroma4) Chondromyxoid fibroma5) Brodies abscess


During an MRI scan, the patient is placed into a very high magnetic field that causes randomly aligned hydrogen atoms to align parallel with thenewly applied magnetic field. Radiofrequency pulses are then applied which elevate the hydrogen atoms to a higher level energy state (repetitiontime = TR = time between pulses applied). When the radiofrequency pulses are terminated, the hydrogen atoms release energy as they return totheir pre-excited state. This energy released by hydrogen atoms is measured in MRI scanning as the relaxation time, or TE. Suffice it to say thatwhen a long TR is applied and the long TE of hydrogen atoms is measured, signal is manifested as high intensity on T2 weighted images.

Benign osteoblastoma (choice B) is a benign lesion of bone composed of connective tissue that tends to produce osteoid and bone in its matrix. It


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is more common in males than females and tends to occur in the 2nd and 3rd decades of life. Mild pain is generally the presenting symptom withsome tenderness possible at the site. This lesion most frequently occurs in the long tubular bones and in the posterior elements of the vertebraeand characteristically has low signal intensity on T2 weighted images due to the presence of osteoid and bone within the lesion, and a lowhydrogen content.

The remaining choices in the benign lesions of bone listed all have a high hydrogen content and hence high signal intensity on T2 weightedsequencessimple bone cyst (choice A), enchondroma (choice C), chondromyxoid fibroma (choice D), and Brodies abscess (choice E) would all

demonstrate low signal intensity on T1 weighted images and high intensity signal on T2 weighted images due to content within the lesions asfollows: simple bone cystfluid content, enchondroma - high water and mucopolysaccharide content, chondromyxoid fibromachondroid andmyxoid content, Brodies abscess inflammatory content.

A 52 year old male presents to the emergency room in winter with a one week history of flu-like symptoms which have now suddenly gotten muchworse with a fever of 102 degrees, and onset of a very productive cough. You are reading his chest X-ray (shown here) in which you suggest thathe has pneumonia.

Which of the following portions of the lung(s) show air-space consolidation?


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1) Right middle lobe (RML)2) Right lower lobe (RLL)3) Left lower lobe (LLL)4) RLL & LLL5) RML, RLL & LLL


The RML, RLL, and LLL (choice E) all show air-space consolidation as evidenced by silhouetting of the right heart border, the right hemidiaphragm,and the left hemidiaphragm respectively.


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The history and CXR appearance in this patient favor a diagnosis of influenza with the development of a secondary bacterial pneumonia.

None of the other choices AD are all inclusive of the RML, RLL and LLL, and are therefore incorrect.

A 42 year old woman is sent from her gastroenterologists office to radiology for a CT scan of her abdomen. She has been having abdominal pain,

bloody diarrhea, and weight loss. A mid abdominal CT image is as shown.

This radiographic appearance is consistent with which of the following conditions?

1) Ischemic colitis2) Ulcerative colitis3) Pseudomembranous colitis4) Lymphoma5) All of the above


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The mid abdominal CT image shows the transverse colon with a diffusely thickened wall and the classic sign of thumbprinting. The differentialdiagnosis of thumbprinting of the colon includes ischemic colitis (choice A), ulcerative colitis (choice B), pseudomembranous colitis (choice C),and lymphoma (choice D).

Ischemic colitis (choice A) would likely show segmental disease due to occlusion of a particular vessel. Ulcerative colitis (choice B) would tend toinvolve the rectum, which would help to distinguish it from ischemic colitis and Crohns colitis. Pseudomembranous colitis (choice C) due toclostridium difficile usually occurs after a course of antibiotic therapy and tends to involve the entire colon as a potentially distinguishing feature,although ulcerative colitis can do so as well. Thumbprinting with lymphoma (choice D) is often asymmetric and irregular, and its onset would beinsidious as compared to the other conditions listed.

Other conditions that should also be included in the differential for thumbprinting of the colon are endometriosis in women, amyloidosis, hereditaryangioneurotic edema, Crohns disease (although thumbprinting is less commonly seen than with ulcerative colitis) and pneumatosis intestinalis (inwhich case air would be identified in the colonic wall).

You are about to perform an abdominal CT scan on a 67 year old male who has been diagnosed with colon cancer.

Regarding the radiation received from this CT scan, what is the approximate time period for equivalent effective dose from natural background

radiation?

1) 2.5 days2) 26 weeks3) 1 year4) 3 years5) 9 years



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An abdominal CT scan has an approximate time period for equivalent effective dose from natural background radiation of 3 years (choice D).

In general, the higher the dose and duration of radiation during the study, the greater the time period for equivalent effective dose from naturalbackground radiation.

2.5 days (choice A) is the approximate time period for equivalent effective dose from natural background radiation for a typical chest X-ray. 26weeks (choice B) is the approximate time period for equivalent effective dose from natural background radiation for a typical lumbar spine X-ray. 1year (choice C) is the approximate time period for equivalent effective dose from natural background radiation for a typical intravenous pyeologram(IVP). 9 years (choice E) would be the approximate time period for equivalent effective dose from natural background radiation for three abdominalCT scans.

A 73 year old man with hypertension secondary to chronic renal failure presents to the emergency room after experiencing tearing chest pain which

radiates to his back. He is fearful that he is having a heart attack. Physical examination reveals a bruit over the patients upper back and

asymmetrical pulses in the lower extremities. Blood pressure is 160/95. Due to the patients chronic renal failure, an MRI iselected as the imaging

modality to make his diagnosis, an oblique coronal image of which is shown here.

With regard to this patients diagnosis, which of the following radiographic studies readily makes this diagnosis?


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1) CT scan2) MRI3) Arteriography4) Trans-esophageal ultrasound5) All of the above


All of the above (choice E) answers are correct in this case as each of the imaging modalities (CT scanA, MRIB, arteriographyC, and trans-esophageal ultrasoundD) can make this patients diagnosis dissecting aortic aneurysm type III.

The wall of the aorta, from lumen to exterior, is comprised of intima, media, and adventitia. A dissecting aortic aneurysm results from a tear of theintima, leading to the formation of a false lumen in the media portion of the aortic wall. Blood may flow in this false lumen and rejoin the true lumenmore distally, or blood may simply clot within the false lumen and remain static. Dissecting aortic aneurysms are classified into three types:

Type Idissection involves the ascending and descending aorta, originating just above the aortic valve.

Type IIdissection involves only the ascending aorta, originating just above the aortic valve.

Type IIIdissection involves only the descending aorta, originating below the level of the left subclavian artery.

This diagram illustrates the three classifications of aortic dissection, but uses A, B, C instead of I, II, III:


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There is a male to female predominance of this condition of 3:1 and risk factors include hypertension, Marfans syndrome, coarctation of the aorta,valvular aortic stenosis with post-stenotic dilatation, and presence of a prosthetic aortic valve. Symptoms and signs may include sharp, tearingchest pain that radiates to the back, bruit, aortic regurgitation, asymmetric peripheral pulses, bowel ischemia, neurological deficits, cardiacischemia, and oliguria. These findings all depend on which vessels become involved in the dissection. Trans-esophageal ultrasound (choice D) canbe used to make the diagnosis of dissecting aortic aneurysm, and due to the proximity of the descending aorta to the esophagus, this mode isparticularly useful in diagnosing Type III aortic dissections. Conventional arteriography (choice C) is a very effective method of diagnosing adissecting aortic aneurysm, but this method is rarely used currently as it has been supplanted with CT scanning, and to a lesser extent, MRI. The


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classic findings on arteriography are the demonstration of an intimal flap (the longitudinal physical structure that separates the true from the falselumen) and the presence of a false lumen. Liekwise, CT scanning (choice A) and MRI (choice B) readily show the intimal flap and false lumen, andare much less invasive and more readily available examinations, especially CT scanning.

A 48 year old male presents to his physician with complaints of dysphagia for solids over the last 6 weeks with mild retrosternal pain while eating.

Review of systems reveals that the patient smoked 1 pack of cigarettes per day from the ages of 20-32 years. He consumes 5-6 drinks of alcohol

per week. Physical examination and screening laboratory tests are entirely normal. The physician sends the patient to radiology for an upper GI

(UGI) examination for further evaluation. You are performing the UGI and note an abnormality of lower esophagus during fluoroscopy. A spot film ofthe lower esophagus is shown here.

The most likely diagnosis in this patient is:


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1) Achalasia2) Hiatal hernia3) Esophageal leiomyoma4) Esophageal cancer5) Esophageal varices


The spot film of the lower esophagus shows a large (approximately 10 cm), round, smooth intramural filling defect of the distal left lateralesophageal wall just above the gastro-esophageal junction. Note is made that the esophageal mucosa is intact, hence smooth. Thesefindings aremost consistent with an esophageal leiomyoma (choice C).

Esophageal leiomyoma is the most common benign tumor of the esophagus. Most of these tumors are asymptomatic unless large enough to causedysphagia and substernal pain. Leiomyomas are most frequently found in the distal third of the esophagus. These tumors are determined to beintramural on barium studies because of their nonacute angular interface with adjacent unaffected esophagus. (Mucosal lesions tend to have anacute angular interface with adjacent normal mucosa.) These lesions may rarely contain enough calcification to be detected on X-ray, and if so, isdiagnostic as no other lesions of the esophagus are known to contain calcifications. Leiomyomas of the esophagus rarely ulcerate, unlike theircounterparts in the stomach. Few esophageal leiomyomas will undergo malignant transformation into leiomyosarcomas.

Achalasia (choice A) is a functional obstruction of the distal esophagus due to incomplete relaxation of the lower esophageal sphincter combinedwith decreased motility of the esophagus. This condition is due to a paucity of myenteric plexes and cholinergic innervation of the distal esophagus.Dysphagia is a symptom of achalasia, but radiologic findings on barium esophagram demonstrate a gradual, smooth narrowing of the distalesophagus with intact mucosa offering a classic beak-like appearance of the distal barium column. Achalasia is therefore an incorrect answer and

an image of this condition is shown here:


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Hiatal (hernia choice B) is an extremely common problem that is defined as a portion of the stomach lying above the diaphragm within the thoracic

cavity. Symptoms may include heartburn, pain, and dysphagia. Diagnosis is made by determination of the gastroesophageal junction (Shatzkisring) or gastric mucosa above the diaphragm within the thoracic cavity. Therefore, hiatal hernia is an incorrect choice in this case.

Esophageal cancer (choice D) is an incorrect choice in this case as radiographically on barium study it would appear as an irregular, polypoid,fungating mass with interruption of the mucosa, and possible deep ulceration. In addition, the mass would have acute, overhanging margins withadjacent normal mucosa.


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Esophageal varices (choice E) is also an incorrect choice in this case as they appear as smooth, serpiginous filling defects of the distal esophagusthat run parallel with the esophagus. Overlying mucosa is also normal in this condition and changes in form may be noted with respiration onfluoroscopy.

A 74 year old man is seen in GI clinic with complaints of decreased appetite, early satiety, and weight loss. The patients physical examination is

unremarkable but Hemoccult fecal blood test is positive. The patient is sent to radiology by the gastroenterologist for an upper GI examination,which you perform. An image from that examination in which you suspect that the patient has a malignant ulcer is as attached.

Regarding malignant vs. benign ulcers in the stomach, all of the following statements about malignant ulcers are true except for:


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1) Ulcer location is within the margin of the gastric lumen2) Ulcer location is more likely to be on the greater curvature than the lesser curvature

3) Gastric folds radiate toward the ulcer4) Ulcer is irregular in shape with a nodular floor5) Presence of Carman meniscus sign


Gastric folds in a malignant ulcer typically do not radiate toward the ulcer crater (choice C). This finding is a characteristic of benign ulcers. A


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benign gastric ulcer with folds radiating toward the crater and the crater projecting outside the gastric lumen is shown here:

Folds in malignant ulcers tend to be irregular, not directed toward the ulcer, and may be clubbed or amputated in the region of the ulcer.

Malignant ulcers tend to project within the margin of the gastric lumen (choice A) where as benign ulcers tend to project outside the margin of the

t i l


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gastric lumen.

Malignant ulcers tend to favor the greater curvature (choice B) as opposed to benign ulcers which favor the lesser curvature. (There is an obviousexception to this general characteristic in the case presented here.)

Malignant ulcers tend to be irregular in shape with a nodular floor (choice D) whereas benign ulcers tend to be quite regular with sharp margins.

The Carman meniscus sign is a radiographic appearance of gastric malignancy that is created by a large, flat ulcer with heaped-up edges whichtrap a lenticular barium collection that is convex toward the lumen when the edges are folded upon themselves during compression.


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A 53 year old woman presents to her family physician and complains of progressive hearing loss and tinnitus in her right ear. She also complains of

occasional dizziness. Her symptoms have been progressively getting worse over the last 6 weeks. Neurological examination suggests a

sensorineural hearing loss on the right, but no other significant abnormality. The patient is sent to radiology for an MRI of her brain. A T1 weighted

image post intravenous contrast from that study is shown here.

Which of the following is the most likely diagnosis in this patient?


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1) Meningioma2) Acoustic schwannoma3) Epidermoid tumor4) Arachnoid cyst5) Metastatic lesion

The correct answer is choice B


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The MRI shows an intensely enhancing lesion of the right internal auditory canal that spills out into the region of the cerebellopontine angle in theshape of an ice-cream cone, a very typical appearance for an acoustic schwannoma (choice B).

Acoustic schwannoma is the most common lesion of the cerebellopontine angle (CPA), making up 70-80% of tumors in this location. They occur infemales more commonly than males at a ratio of 2:1, and about 5% are associated with neurofibromatosis type II. Acoustic schwannomas typicallypresent anywhere from 3560 years of age with sensorineural hearing loss on the side of the tumor, associated tinnitus, and possible dizzinessand vertigo. Radiologic findings on MRI, which is the imaging study of choice, typically are seen as mass lesions aligning themselves along thecourse of cranial nerve VII, perhaps enlarging the internal auditory canal (IAC), extending out of the IAC, and forming an ice-cream cone shapedmass which intensely enhances in a homogeneous manner post intravenous administration of gadolinium.

Meningioma (choice A) is the second most common CPA tumor, accounting for approximately 10-15% of tumors in this location. Meningiomas inthe CPA characteristically have a broad base on the side of their meningeal origin and project a more spherical margin toward the opposite side,and for this reason, choice A is incorrent. Meningiomas also tend to enhance intensely and homogeneosly. If these CPA tumors become largeenough, they may also produce sensorineural hearing loss. As a distinction from acoustic schwannomas, if they do extend into the IAC, they nottypically enlarge it.

Both epidermoid tumors (choice C) and arachnoid cysts (choice D), although cause can cause mass lesions of the CPA, they do not enhance postintravenous gadolinium administration, and are therefore incorrect choices in this case.

Metastatic lesions can occur at the CPA (choice E) and cause enhancing lesions, but these lesions are far less common than acousticschwannomas and tend to be multiple when they do occur. This choice is therefore incorrect.

An 84 year old man who has had multiple recurrent episodes of suspected aspiration pneumonia over the last 2 years is being evaluated in the

radiology department with an upper GI (UGI) examination to assess for gastroesophageal reflux (GER) as a potential cause for the pneumonias.

You are the radiologist performing the examination and you are able to demonstrate GER fluoroscopically during the examination. The final

overhead image of that study is presented here which shows evidence of gastroesophageal reflux and scarring in the left mid lung secondary to the

ti t hi t f t i d f i ti i D l ifi ti f t h d l til ( ti l l th i ht) ll


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patients history of recurrent episodes of aspiration pneumonia. Dense calcification of costrochondral cartilage (particularly on the right) as well as

of the iliac arteries bilaterally are also noted.

With relationship to radiopacity seen on plain x-ray images, which of the following is correct in listing these opacities from the most radiopaque to

the least?

1) Bone metal soft tissue fat air


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1) Bone, metal, soft tissue, fat, air2) Metal, bone, soft tissue, air, fat3) Metal, bone, soft tissue, fat, air4) Metal, bone, fat, soft tissue, air5) Bone, metal, fat, soft tissue, air


There are 5 basic radiodensities encountered in plain x-ray which are listed here from highest to lowest in their radiopacity: metal, bone, soft tissue,fat, air (choice C). The remainder of the choices (A, B, D, & E) contain the wrong order of these components radiodensity and are therefore allincorrect answers.

The image seen on plain x-rays is the result of the degree of penetration of x-rays through the body, or body parts, that ultimately reach and exposethe x-ray cassette detectors. The more radiopaque a material is, the less penetration of the x-ray, and the less exposed the cassette detectorsbecome. Conversely, the less radiopaque a material is, the more penetration of the x-ray, and the more exposed the cassette detectors become.Said another way, the degree of radiodensity of a material is inversely proportional to the degree of exposure on x-ray cassette detectors through

that material. No exposure results in pure white on x-ray image, complete exposure results in pure black on x-ray image. Radiodensities recordedby x-ray cassette detectors in imaging of the body lie in between pure white and pure black on x-ray image, and it is the relative relationships ofthose radiodensities that allow the interpreter of the x-ray image to extract information from the image.

There are 5 basic radiodensities encountered in plain x-ray listed here from highest to lowest radiopacity: metal, bone, soft tissue, fat, air. (The softtissue category contains water-based bodily fluids; fat-based bodily fluids such as chyle would be contained in the fat density category.) Theradiodensities of the metal and bone categories have to do with the atomic numbers of the components within those categories. The higher thecomponents atomic number is, the more absorption of the x-ray beam, the more radiopaque, the less exposure of the x-ray cassette, and the

whiter the image. So, with barium, which is a metal, having an atomic number of 82 and calcium within bone having an atomic number of 20,barium will appear more radiopaque than bone. (Bone is further less radiopaque than barium due to the presence of organic matrix within bonecontributing to further radiolucency than that of pure calcium.) The relative radiodensity of the remaining categories of soft tissueair and fat, is theresult of the physical densities of their compositions.

Relative to the overhead x-ray image shown, barium, a metal is seen within the GI tract from the esophagus to the colon, and appears as the mostradiopaque material on the image. The next most radiopaque component is calcium seen in bone, vessels and chostrochondral cartilage. Following

in radiopacity is soft tissue density well demonstrated here by the liver Next is fat density well seen on this film in the subcutaneous region on the


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in radiopacity is soft tissue density, well demonstrated here by the liver. Next is fat density, well seen on this film in the subcutaneous region on theright, and lateral to the psoas muscles bilaterally. Finally, the least radiopaque component seen is that of air in the lungs.

Also relative to this discussion is the fact that the thicker a specific tissue component is, the more absorption of the x-ray beam, the less exposureof the x-ray cassette, and the whiter the resulting image. This principle is exemplified by the comparison of a chest or abdominal image taken of aslightly built patient vs that of a heavy-set patient using the same kilovoltage and time of exposure. The heavy-set patients image will appear lighterthan that of the slightly built patient due to the increased absorption of the x-ray beam by the greater thickness of tissue present in the more heavy-

set patient.

A 72 year old male presents to a walk-in clinic with complaints of a persistent dry cough, dyspnea, right-sided chest wall pain, fatigue, fever, night

sweats and weight loss, all having progressed over the last year. When asked why the patient had not sought medical attention sooner, he

responded that he did not have health insurance and could not afford it. Past medical history revealed that he worked in a shipyard from the ages of

20-40. On physical examination the patient was cachectic with a temperature of 100. Breath sounds were markedly diminished on the right side,

and completely absent at the right base. A chest X-ray was obtained at the walk-in clinic, which prompted the physician to order a CT scan of the

patients chest, which you are interpreting. A representative image of the examination is presented. No parenchymal lung disease is noted on other

images of the CT scan.

What is your primary working diagnosis in this patient?


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1) Lymphoma2) Tuberculous empyema3) Pancoast tumor4) Malignant mesothelioma5) Metastatic disease


This patients chest CT scan shows extensive, bulky, lobular masses of the pleura on the right side. The distal esophagus and IVC appear to beencased as well. There is a large right-sided pleural effusion and a hint of ascites under the right diaphragmatic crus. In a patient with anoccupational history of working in a shipyard where asbestos exposure is highly likely, the primary working diagnosis in this patient is malignantmesothelioma (choice D).

Malignant mesothelioma is an uncommon tumor of mesothelial cells that line the pleura, usually associated with a history of chronic asbestos

exposure although asbestos exposure is not a prerequisite for the disease The incidence of this disease is increasing and currently occurs in the


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exposure, although asbestos exposure is not a prerequisite for the disease. The incidence of this disease is increasing, and currently occurs in theUnited States at a rate of about 2,500 new cases per year. Radiographic findings include a large pleural effusion in approximately 90% of caseswhich may progress to a fibrothorax. This may be the only detectable finding on plain chest X-ray. Pleural masses and/or pleural rind are usuallybetter visualized on chest CT scan. Chest wall invasion is not uncommon in later-stage cases. Definitive diagnosis is made by biopsy. The earlierthe diagnosis is made, the better the outcome for the patient.

Lymphomatous involvement of the pleura (choice A) can occur in association with mediastinal and parenchymal involvement in the chest, but with

this patients history of occupational exposure, it would not be the primary working diagnosis.

Tuberculous empyema (choice B) is most frequently associated with a calcified pleural rind and evidence of parenchymal disease of the upperlobe(s).

Pancoast tumor (choice C) refers to a tumor that involves the apical pleura and would not be present at the lung base.

Metastatic disease to the pleura (choice E) is uncommon but can occur with the most likely primary tumors being bronchus, breast, ovary and GItract. This condition is also frequently associated with a pleural effusion. Although this diagnosis should be included in the differential, malignantmesothelioma is more likely in this patient due to his occupational exposure.

A 57 year old woman who is a long-time cigarette smoker has recently been diagnosed with biopsy proven lung carcinoma. She is in the radiology

department today undergoing an abdominal CT scan as part of her work-up to rule out metastatic disease. While reviewing her abdominal CT scan,

you are going to be particularly interested in her adrenal glands, liver, and look for potential lymphadenopathy as well as any other abnormality

within the abdomen. While observing the initial noncontast CT scan being done, you notice that there is a well circumscribed 3 cm round lesion of

the left adrenal gland with a low attenuation center (see associated image presented). Both size and density of the lesion can be helpful in

suggesting whether the lesion may be benign or malignant so you ask the CT technologist to go back after the scan to do ultra-thin sections

through the left adrenal gland and obtain Hounsfield measurements of the visualized lesion before the administration of IV contrast. The Hounsfield

units obtained at that point are in the 8-10 range.

Regarding lesions of the adrenal glands, which of the following could possibly demonstrate Hounsfield density unit measurements in the 8-10

range?


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range?

1) Myelolipoma2) Pheochromocytoma3) Myelolipoma and adrenal adenoma4) Myelolipoma and pheochromocytoma5) Metastasis to the adrenal gland


Myelolipomas of the adrenal gland and up to 60% of adrenal adenomas (choice C) will generally have lipid content within that can place Hounsfielddensity unit measurements in the 8-12 range, as in this case. In general, although with exceptions, adrenal masses < 4 cm in size with < 10Hounsfield units in density tend to be benign lesions. Adrenal adenomas are the most common benign lesions of the adrenal. Most adenomas aresmall (< 5 cm) and nonsecretory, and of those that are secretory, the majority are cortisol secreting. Myelolipomas are also small benign tumors ofthe adrenal that contain lipid and hematopoetic tissue. They are functionally inactive and of little clinical significance unless they become large and

exert mass effect, which is quite rare.


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exert mass effect, which is quite rare.

Myelolipoma alone (choice A) would demonstrate Hounsfield density unit measurements in the 8-12 range, but so could up to 60% of adrenaladenomas, so choice C is the correct answer.

In contrast, pheochromocytomas (choices B & D), adrenal carcinoma, and metastasis to the adrenal gland (choice E) are all malignant processesthat characteristically do not demonstrate low Hounsfield unit density measurements on noncontrast enhanced CT scans as the other conditionslisted do.

A 68 year old male presented to the emergency room with mid-abdominal and back pain, a sensation of fullness in his abdomen, and fatigue. On

physical examination his blood pressure was 98 over 60 and he was found to have a pulsatile mass in his mid abdomen. His hematocrit came back

with a value of 26. The emergency room physician asked the patient if he had noticed any blood in his stool and the patient replied that he had

seen some dark, reddish black blood in his stool intermittently over the last 3 days. The patient is then sent to the radiology department for a CT

scan of his abdomen, which is performed with intravenous contrast, but without oral contrast. A mid-abdominal image from this study is shown.

Based on this CT image, which of the following is the correct diagnosis?


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1) Abdominal aortic aneurysm (AAA)2) Leaking abdominal aortic aneurysm3) Aortico-enteric fistula (AEF)4) Hemoperitioneum5) All of the above


All of the above diagnoses (choice E) are applicable to this patient.

The CT image through the mid abdomen demonstrates an abdominal aortic aneurysm (choice A) with mural thromubus. In addition, there is ill-defined soft tissue streaking of peri-aortic and intra-abdominal fat, consistent with leaking of the aneurysm (choice B) and hemorrhage into theretroperitoneum and peritoneal cavity. Free fluid, presumed to be blood (choice D), is present, seen best in the left paracolic gutter. Of particularnote, bearing in mind that this patient did not receive oral contrast, there is a significant amount of contrast material seen within the lumen smallbowel loops on the left side of the abdomen, as well as in the 4th portion of the duodenum. These findings are consistent with and aorticoduodenal

fistula (choice C).


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( )

Abdominal aortic aneurysms (AAA) are not uncommon sequelae of atheroscleriotic disease. AAA is defined as a greater than 3 cm focal wideningof the abdominal aorta. There is a male to female predominance of 5:1. Many patients with small AAAs are asymptomatic. The larger the AAAbecomes, the more likely that the patient will become symptomatic with awareness of a pulsatile abdominal mass and possible abdominal pain. Thelarger an AAA becomes, the more likely that it will rupture. An AAA with a diameter of 8 cm has an extremely high risk of rupture.

Aortico-enteric fistulas (AEF) are fairly rare and may be classified as primary or secondary. Primary AEF, as in the case presented, is mostfrequently due to atherosclerosis of the aorta. The most common location (88%) for the AEF is the 3rd and 4th portions of the duodenum.Gastrointestinal hemorrhagehematmesis or melena, may be the first symptom of an AEF. Many AEFs are associated with back pain as well.Secondary AEF may result from trauma or iatrogenic causes such as erosion of a suture line. AEF carries high morbidity and mortality rates soearly diagnosis is essential for improved outcome.

You arrive early on the first day of your CT scan rotation as a second year resident. There are a number of CT scans that were done on outpatients

the night before which now need to be read. You are surprised when the first one you pull up shows the attached image. You dig into the patientsmedical record and find that he is a 52 year old male with back pain, hematuria, hypertension, and a history of frequent urinary tract infections. You

make the diagnosis of adult polycystic kidney disease.

This disease is associated with all of the following conditions except for:


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1) Autosomal recessive inheritance2) Hepatic cysts3) Pancreatic cysts4) Urolithiasis

5) Berry aneurysms

The correct answer is choice A.

Adult polycystic kidney disease has an autosomal dominant mode of inheritance. Infantile polycystic kidney disease has an autosomal recessivemode of inheritance (choice A).


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Adult polycystic kidney disease affects 1:6000 people and accounts for up to 15% of patients on dialysis in the U.S. Symptoms such as hematuriaand flank pain usually begin between 30 and 50 years of age. 80% of such patients have associated hypertension. Urolithiasis (choice D) occurs inup to 30% of patients afflicted. Hepatic cysts (choice B) occur in approximately 60% of patients and are seen on the CT scan here. Pancreatic cysts(choice C) are present in 10% of patients. Finally, berry aneurysms (choice E) are present in up to 40% of these patients, and their rupture (9%)may cause of death.

During a routine visit to his family physician, a 51 year old male states that he has low back pain and stiffness, which seems to have come on andprogressed over the past 6 months or so. Review of systems reveals mild anorexia and a 5 lb weight loss over the same time duration. Physical

examination demonstrates limited mobility of the lower spine, but is otherwise unremarkable. Screening blood tests are only significant for a

moderately elevated ESR. The patient is sent to radiology for lumbar spine X-rays, of which the PA view is shown here.

What is the most likely diagnosis in this patient?


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1) Diffuse Idiopathic Skeletal Hyperostosis (DISH)

2) Rheumatoid arthritis


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3) Psoriatic arthritis4) Anklyosing spondylitis5) Reiters syndrome


Ankylosing spondylitis (AS) is a chronic inflammatory disorder that affects mainly the axial skeleton. It affects men more than women at a ratio of15:1. 95% of AS patients are HLA-B27 positive. Onset is usually insidious and frequently presents at ages 1535 years. Complaints are frequentlyof lower back pain and stiffness, with sacroiliac pain as well. Peripheral joint manifestations of the disease can occur in up to 20% of patients. Iritismay also occur in up to 20% of patients. AS can also be associated with pericarditis, aortic insufficiency, pulmonary fibrosis, and inflammatorybowel disease. AS affects synovial and cartilaginous joints, as well as sites of tendon and ligament attachment to bone. Radiologic findings includechanges involving the sacro-iliac joints (SI joints) and spine most commonly. SI joint changes are generally symmetric, predominate on the ilealside of the joint at the middle and lower portions of the joint, and involve loss of definition of the joint, focal sclerosis, later widening of the SI joint,and eventual fusion of the SI joint. Radiologic changes in the spine include straightening and squaring of the anterior vertebral body margins,sclerosis of the vertebral body corners, ossification of the annulus fibrosus, marginal syndesmophyte formation, disco-vertebral erosion anddestruction, and eventual bamboo spine due to the undulating contour of ligamentous calcifications and syndesmophytosis. Ankylosis of thevertebral bodies and apophyseal joints may eventually occur. The anklyosed and bambooed spine may be prone to fracture, resulting in a

pseudoarthrosis. Atlantoaxial subluxation may also occur.

The X-ray in this case shows fusion of the SI joints with areas of sclerosis inferiorly and the classic appearance of a bamboo spine due to theundulating contour of ligamentous calcifications and syndesmophytosis. The dagger sign is also present where ossification of the posteriorspinous ligaments produces a central vertical radiodense stripe, best seen here from L3L5. On a lateral lumbar spine film of a different patientwith AS, straigtening and squaring of the anterior vertebral body margins is seen here:


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DISH ( h i A) i h t i d b th f fl i l ifi ti d ifi ti l th t i t f t b l b di ti


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DISH (choice A) is characterized by the presence of flowing calcification and ossification along the anterior aspect of vertebral bodies, preservationof intervertebral disc height, and absence of SI joint changes, making this an incorrect choice.

When rheumatoid arthritis (choice B) affects the SI joints, it is usually asymmetric or unilateral. Rheumatoid arthritis also has a propensity for thecervical spine and not the lumbar spine. These factors render this choice incorrect.

Psoriatic arthritis (choice C) and Reiters syndrome (choice E), when involving the spine, produce bulky, asymmetric calcified and bony outgrowthswhich are separated from the vertebral bodies and intervertebral discs, and therefore these choices are incorrect in this case.

A 28 year old male who was thrown from his motorcycle after having been hit by an automobile is brought into the emergency room via ambulance.

Upon arrival he is complaining of right back pain. Vital signs show a blood pressure of 95/60, and a heart rate of 138. Cursory physical examination

shows abrasions and contusions of the right flank and right side of the mid torso with mild tenderness on palpation of the abdomen. Stat CBC whichcomes back while the patient is undergoing an emergency body CT scan reveals a hematocrit of 30. You are interpreting that emergency body CT

scan which is performed during the administration of intravenous contrast, an image of which is shown here.

Based on this CT image through the upper abdomen, which of the following is the most accurate description of this patients condition?


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1) Hepatic hematoma2) Subcapsular hepatic hematoma3) Hepatic laceration4) Hepatic laceration with hemoperitoneum5) Hepatic laceration and hematoma with active hemorrhage and hemoperitoneum


The CT image of the upper abdomen shown demonstrates a laceration to the right lobe of the liver and a small hematoma within the lacerationposteriorly. There is also evidence of hemopertioneum posterior to the liver, and evidence of active hemorrhage with high density intravenouscontrast material leaking into the laceration anterolaterally, posteriorly within a small round hepatic hematoma, and out into the freehemoperitoneum. Therefore choice E is the most accurate description of this patients condition.

Abd i l f tl b i j d b bl t t ti t bl t t i th f f t hi l id t f ll d


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Abdominal organs may frequently be injured by blunt or penetrating traumablunt trauma in the form of motor vehicle accidents or falls, andpenetrating trauma in the form of stab wounds or gunshot wounds. CT scanning with intravenous and oral contrast is the ideal imaging modality forevaluation of traumatic injury to the abdomen. In the evaluation of liver trauma, CT is effective for the detection of hepatic lacerations, hepatichematomas, active hepatic hemorrhage, and the presence of hemoperitoneum. The presence of active hepatic hemorrhage and orhemopertoneum are important distinctions to be made as they require interventional management. Hepatic lacerations and hepatic hematomas thatremain within the liver capsule may be managed conservatively, and followed with serial CT scans.

Hepatic lacerations are seen as l inear interruptions in normal liver parenchyma that have irregular margins and contain blood. They may even takeon a branching or stellate pattern. Hepatic hematomas are collections of blood within the liver, perhaps within the laceration, that take on a round oroval shape. Subcapsular hematomas appear as a crescent or oval-shaped lesion immediately deep to the liver capsule which has mass effect andindents the normal liver tissue. Extravasation of intravenous contrast material into a liver laceration or into the peritoneal cavity is seen as highdensity contrast material with Hounsfield units measurements of 30 or greater in the laceration or extending into the peritoneal cavity, indicatingactive hemorrhage.

Hepatic hematoma (choice A) is present in this patient and seen as a small, rounded collection of blood in the inferior aspect of the hepatic

laceration, but does not give a full accurate description of this patients condition and is therefore an incorrect answer.

Subcapsular hepatic hematoma (choice B) is an incorrect choice in this patient as this condition would manifest as a crescent or oval-shaped lesionimmediately deep to the liver capsule, having mass effect and indenting normal liver tissuenot seen in this case.

Hepatic laceration (choice C) and hepatic laceration with hemopertioneum (choice D), while both present in this patient, still do not give a completeaccurate description of the findings on the CT scan leaving out the active hemorrhage component, and are therefore incorrect answers.

You are reading a chest X-ray on a 32 year old black female that has come in through the emergency room. The requisition for the CXR has thetypical rule out pneumonia filled in as the reason for the examination. On the CXR you see mid lung zone interstitial lung disease with minimalbilateral hilar lymphadenopathy. On a comparison CXR from two years ago, you see moderate bilateral hilar lymphadenopathy, but withoutassociated interstitial lung disease.

The most likely diagnosis in this patient is:

1) Hodgkins disease


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1) Hodgkins disease2) Lymphangitic metastases3) Reactivation tuberculosis4) Sarcoidosis5) Pneumocystis carinii pneumonia (PCP)


Sarcoidosis (choice D) is the correct answer as this disease most commonly affects black females between the ages of 2040 years, and has asone of its hallmarks the progression of interstitial lung disease with a reduction in hilar lymphadenopathy over time. Classic egg-shell calcificationsmay also be seen in approximately 5% of patients with long-standing sarcoidosis.

Other interstitial lung diseases may also be associated with bilateral hilar lymphadenopathy, but in the following cases that were offered as choices,the interstitial lung disease is generally in a different distribution than that of sarcoidosis. Lymphangitic metastases (choice B) may have associated

interstitial lung disease that would generally be located in the lower lung zones and reactivation tuberculosis (choice C) may have associatedinterstitial lung disease that would generally be located in the upper lobes. Both choices B & C, as well as choice A Hodgkins disease, would notshow the hallmark of sarcoidosis describeda progression of interstitial lung disease with a reduction of hilar lymphadenopathy over time.

Pneumocystis carinii pneumonia or PCP (choice E) frequently causes a diffuse linear reticular interstitial lung pattern early on in its process, but isnot typically associated with bilateral hilar lymphadenopathy.

A 20 year old male jogger was out for his morning run when at 3 miles he stumbled on the trail and twisted his right ankle. He presents to theemergency room with complaints of pain and swelling of his right ankle. Physical examination reveals point-tenderness over the distal right fibula

with soft-tissue swelling and bruising in the area. The patient is sent to radiology for X-rays of his right ankle, an image of which is shown here.

With regard to bone fractures, in addition to examining X-rays for breaks in continuity of bone cortex and radiolucent fracture lines, which of the

following should also be sought?


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1) Overlap of cortical and spongy bone creating an abnormally white zone

2) Unexplained fragments of bone even in the absence of a visible fracture3) Dense areas of bone seen in 2 views where impaction has occurred


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3) Dense areas of bone seen in 2 views where impaction has occurred4) Flocculent calcific density in soft tissue adjacent to bone5) All of the above


In addition to examining X-rays for breaks in continuity of bone cortex and radiolucent fracture lines, all of the above (choice E) radiographic signsshould be looked for in the evaluation of bone fractures.

Choices AC above are self-explanatory. Flocculent calcific density in soft tissue adjacent to bone (choice D) signifies callus formation in a healingbone fracture and indicates that a subacute fracture is present.

The X-ray shown demonstrates a spiral fracture of the distal right fibula with minimal lateral displacement of the distal fragment and overlying soft-tissue swelling.

The descriptions of fractures on X-ray are important so as to convey specific information to the orthopedist. Fractures may be transverse, oblique,or spiral in orientation. They may be completehaving broken through both cortical surfaces of the bone, or incompletehaving broken throughonly one surface of bone. Incomplete fractures, often called greenstick fractures are common in growing children whose bones contain morefibrous material than those in adults. Fractures may be simplewith no bony fragment(s) involved, or comminutedwith bony fragments involved.Compound fractures describe fractures in which bone has broken through the skin surface. An avulsion fracture refers to a fracture in which a smallfragment of bone is traumatically pulled off a bone by a tendon or ligament at its insertion site. Intra-articular fractures describe fractures that extendinto joint spaces. A stress fracture may result when there is abnormal stress exerted on bone. Fatigue fractures are stress fractures that occurwhen abnormal stresses are applied to normal bone, such as in the case of march fractures in the metatarsals of military recruits. Insufficiencyfractures are stress fractures that occur when normal stresses are applied to abnormal bone, such as in the case of a compression fracture of avertebral body in an older woman with osteoporosis. A pathologic fracture is a descriptive term reserved for a fracture in an abnormal bone that isrendered soft, such as in the case of bone cysts or in Pagets disease.

In addition to the descriptors listed above it is important to also convey the location of the fracture its alignment degree of angulation of the distal


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In addition to the descriptors listed above, it is important to also convey the location of the fracture, its alignment, degree of angulation of the distalfragment, and amount of override if any is present.

If there is a high clinical suspicion of a bone fracture, but there is no evidence to support it on plain X-ray, a CT scan should be performed of thearea in question as this imaging modality is far more sensitive in the detection of fractures than plain radiography.

A 62 year old male presents to the emergency room with complaints of sharp right upper quadrant pain that comes in waves and lasts for hours. He

has been experiencing this pain intermittently over the last 2 days as well as a loss of appetite and general malaise. Physical examination reveals a

temperature of 100.3, RUQ tenderness and guarding, and no evidence of jaundice. The ER physician sends the patient to radiology for a RUQ

ultrasound, which you are interpreting. An image of that ultrasound is shown.

What is your leading diagnosis?

1) Acute cholecystitis2) Chronic cholecystitis


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2) Chronic cholecystitis3) Acalculous cholesystis4) Emphysematous cholecystitis5) All of the above

The correct answer is choice A.

The ultrasound shows a longitudinal image through the gallbladder which contains multiple nonechoic gallstones mixed with sludge. There isthickening of the gallbladder wall with a measurement of > 3 mm. There is also a hazy delineation of the gallbladder wall consistent with itsinflammation. These ultrasonographic findings combined with the patients history suggest a diagnosis of acute cholecystits (choice A).

Other important ultrasonographic findings in acute cholecystitis are a positive ultrasound Murphys sign which refers to the elicitation of pain whenthe ultrasound probe is pressed against the gallbladder. The presence of pericholecystic fluid is another frequent sign found in acute cholecystitis.The gallbladder wall may demonstrate a linear lucency due to edema within, producing the halo sign, which is also associated with acutecholecystitis. Frequently, gallstones present will be calcified and therefore echogenic with limited through transmission.

Cholecystitis occurs more frequently in females than males at a ratio of 3:1, peaking in the 4th6th decades of life. The classic mnemonic is the 4Fs Female, Fat, Forties, and Fertile.

90% of acute cholecystits is secondary to cystic duct obstruction by an impacted calculus with secondary chemical irritation to the gall bladder wallfrom concentrated bile, possible bacterial infection, and reflux of pancreatic secretions if a calculus becomes lodged distally in the sphincter ofOddi.

Chronic cholecystitis (choice B) does not fit the clinical history of this patient. The ultrasound appearance of chronic cholecystitis would likely showa small, contracted gallbladder with a thickened wall, containing calculi. Calcification of the gallbladder wall can occur in this condition forming aporcelain gallbladder.

Acalculous cholecystitis (choice C) is not common and probably occurs secondary to decreased blood flow through the cystic artery for a variety of


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Acalculous cholecystitis (choice C) is not common and probably occurs secondary to decreased blood flow through the cystic artery for a variety ofreasons. The patient presented here demonstrated gallstones on the ultrasound so this choice does not apply.

Emphysematous cholecystitis (choice D) refers to a severe form of cholecystitis that most frequently occurs in diabetic males. Ultrasound woulddemonstrate high levels of linear echogenicity outlining the gallbladder wall due to the gas contained within the wall. This condition carries a risk ofgangrene and perforation of the gallbladder.

A 27 year old female who was walking in a somewhat dangerous part of town late at night is brought into the emergency room via ambulance after

having been stabbed during a mugging in which the thief made off with her purse. The young woman arrives in severe respiratory distress with a

blood pressure of 90/60, heart rate of 120, and respiratory rate of 40. The clothing on the left side of her body is bloody. Cursory physical

examination reveals decreased breath sounds on the left. A portable chest x-ray is immediately obtained and that image is shown here.

What is your primary diagnosis in this patient?


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1) Pneumothorax2) Tension pneumothorax3) Hemothorax4) Lung contusion/injury5) Right lung volume loss with ipsylateral shift of mediastinum


This patients diagnosis is tension pneumothorax (choice B) based on the chest x-ray findings of a large left-sided pneumothorax with mediastinalshift to the right, or contralateral side.

Tension pneumothorax is a serious, life-threatening condition. It is associated with a ball-valve type mechanism in which increased volume of airand pressure accumulates in the pleural space so as to cause shi

diagnostic imaging and radiology

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