radiology of adrenals
TRANSCRIPT
من أوتيتم وماقليال� العلم إال�
آية- االسراءسورة 85
الله صــدقالعظـــيم
الرحمن الله بسمالرحيم
ZAGAZIG UNIVERSITY HOSPITALS
RADIOLOGY DEPARTMENT
By
Mohammad BashaLecturer of Radio-diagnosis
What is radiology? It is a medical specialty that employs the use of
imaging to both diagnose and treat disease within the human body.
What is the Adrenal glands? The adrenal glands (also known as suprarenal
glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldostrone and cortisol. They are found above the kidney.
ObjectiveTo know:
Normal Anatomy of Adrenal Gland.Imaging Modalities of Adrenal gland.D.D of Adrenal Masses.Imaging Appearance of adrenal masses.Imaging Work UP of adrenal incidentaloma.Questions.
Normal Anatomy
Normal Anatomy The adrenal glands are two small, retroperitoneal yellowish organs located in the perirenal space, immediately anterosuperior to the upper pole of the kidneys.
Yellow appearance because of their high lipid content.
Gerota’s fascia connect the gland to upper pole of the kidney
Right adrenal is triangular, related to upper pole Right kidney.Left adrenal is crescent shaped, related to upper and medial part Left kidney.Average size is 3-5 cm long, 2-3 cm wide and 5 mm in thickness. Average weight is 3-5 g of which 90 % is contributed by cortex.
Normal Anatomy
Vascular SupplyReceive arterial blood from branches of the inferior phrenic artery, aorta, and renal arteries.
The right adrenal vein is short and exits the gland medially to enter the vena cava.
The left adrenal vein exits anteriorly and usually drains into the left renal vein.
As a result, adrenal venous catheterization is accomplished more easily on the left than the right.
The adrenal gland is composed of an outer cortex and thinner inner medulla.
The cortex is further subdivided into three zones: outer zona glomerulosa-site for aldosterone synthesis, middle zona fasciculata, and inner zona reticularis produce both cortisol and androgens.
RT ADRENAL Anteriorly: IVC and Liver Posteriorly: Diaphragm
LT ADRENAL Anteriorly: Pancreas and Stomach Posteriorly: Diaphragm
Relations
Axial CT scan demonstrating normal right and left adrenal glands with inverted ‘ Y’’ shapes
above both kidneys.
Coronal CT scan demonstrating normal right and left adrenal glands with inverted ‘ Y’’ and ‘ V’’ shapes respectively located above
both kidneys.
Coronal T1-weighted MR image shows the normal inverted Y shape of the right
adrenal gland (arrow).
Normal adrenal gland in an infant
Imaging Modalitie
s
Imaging Modalities1.Plain Film.2. IVU.3.Ultrasound.4.CT.5.MRI.6.Radioisotope Scanning.7.PET and PET-CT Imaging.8. Interventional imaging.9.Adrenal Biopsy
Imaging ModalitiesThe use of CT, MR imaging, and PET exploit three fundamentally different physiologic principles:
1.The intracellular lipid concentration of the mass.
2.The perfusion differences between benign and malignant masses.
3.The metabolic activity of the mass.
Plain FilmsLimited role.
Demonstrate a soft tissue mass or tumefaction possibly displacing the kidney
Demonstrate calcifications (idiopathic, neoplasm, granuloma, cyst, old hemorrhage and Wolman’s disease)
Left: Plain film showing bilateral stippled adrenal calcification. Right: Large left supra renal mass (M) with low fat density, mass effect on the upper pole of the left kidney is noted in this case of left adrenal myelolipoma
IVU The mass may cause lateral and downward
displacement and flattening of the corresponding renal pelvi-calyceal system causing the drooping–lily sign.
Intravenous urogram (IVU) shows a classic drooping-lily sign involving the right kidney. This patient had a known right adrenal neuroblastoma
UltrasoundOften adrenal masses are incidentally detected with abdominal ultrasound.
Ultrasound can differentiate solid from cystic masses.
The location, size, echopattern and vascularity of masses are assessed using color Doppler imaging.
CTIs the most effective technique for examining the adrenal glands. The imaging procedure of choice for most patients with known or suspected adrenal lesions. Perinephric fat allows the gland to be displayed clearly.Sensitivity up to 100% in identifying tumors as small as 10 mm.CT can demonstrate the adrenal glands in all patients and can usually identify the size, location, appearance, and presence of local or vascular invasion, lymph node involvement, and presence of distant metastases.
5 mm collimated slices and even narrower collimation may be used to clarify equivocal findings.Start by performing an unenhanced CT. If the attenuation value is <10HU, then the mass is characterized as lipid rich adenoma and no further workup is done. Inverse linear relationship between lipid concentration and attenuation value on unenhanced CT.
CT Protocol
If the attenuation value is >10 HU, then intravenous contrast is administered (125 cc of Ultravist, administered at a rate of 3 cc/s) and images obtained during the portal venous phase with a 65-80 sec scan delay, and then 15 min delayed images are acquired.
When oral contrast material is being used, administer 1000 mL of water at the time of the study.
Typically the ROI should be placed over one-half to two-thirds of the lesion surface and avoiding necrotic or hemorrhagic areas.
CT Protocol
CT ProtocolLastly, the absolute and relative enhancement washout calculations are performed.
Absolute enhancement washout (APW)=Enhanced attenuation value-Delayed enhanced valueEnhanced attenuation value-Unenhanced attenuation value
Relative enhancement washout (RPW)=Enhanced attenuation value-Delayed enhanced value Enhanced attenuation value
CT ProtocolMost investigators use a 40% threshold on a 15-minute delayed scan for RPW or 60% for APW.
Therefore, any lesion that demonstrates RPW > 40% or APW > 60% at this time is consistent with an adenoma, with sensitivity and specificity both close to 100%.
Lesions that demonstrate RPW < 40% or APW < 60% on a 15-minute delayed scan are almost always malignant.
CTThe washout CT technique have some limitations:
Most standard CT scans are now obtained after IV contrast, and therefore the unenhanced attenuation value cannot be obtained, and to reschedule the patient for a dedicated CT adrenal protocol is burden to the patients.
The possibility exists that an adrenal carcinoma contains foci of intracytoplasmic lipids, as well as exceptionally metastatic from clear cell renal carcinoma and hepatocellular carcinoma.
MRIA typical MRI protocol for adrenal imaging
includes three plane localizer to make proper coverage.
High quality axial T1 and T2 weighted images (3–5 mm) sections preferably with suspended respiration are standard.
Chemical shift imaging is now standard.
MRITypically a standard dose of intravenous
gadolinium contrast is also given and breath-hold T1 weighted images repeated.
Fat-abundant lesions will be bright on T1WI
Fluid-abundant lesions will be bright on T2 (mets, pheo)
MRI-Chemical ShiftPrinciple:
Based on the differences in resonance frequencies between fat protons and water protons when subjected to magnetic field.
At a known time interval, the protons are out-of phase, and their signals cancel out.
By timing images based upon this interval, we can determine the fat content of a certain tissue.
Used to differentiate adenomas from non-adenomas.
MRI-Chemical Shift In phase: water and lipid are aligned so signal intensity
high.
Opposed phase: opposite from each other so signal intensity low.
Interpretation: loss of SI within adrenal mass on an opposed phase image when compared with in-phase image indicates presence of intracellular lipids.
India Ink Artifact: dark line indicative of fat-fluid interface when macroscopic fat is present
MRI-Chemical Shift The chemical shift phenomenon can be measured
either qualitatively (visual) or quantitatively.
Quantitative measurement is done by calculating the adrenal-to-spleen (ASR) chemical shift ratio and signal intensity index (SII).
ASR= (SIAO/SISO)/ (SIAI/SISI)
ASR of less than 0.71 indicates a lipid-rich adenoma.
MRI-Chemical ShiftSII= [(SIAI-SIAO)/ SIAI] X100
SII of more than 16.5% is also consistent with a lipid-rich adenoma.
However, most radiologists evaluate any chemical shift change visually or qualitatively, and this has been reported to be as effective as quantitative methods.
MRI-Chemical Shift (C.S)Chemical shift MR imaging has some limitations:
It is difficult to obtain images of adequate quality with a section thickness of less than 5 mm in a single breath hold with two-dimensional pulse sequences. Volume averaging with the SI artifact on out-of-phase MR images along the adrenal margins has the potential to artificially reduce SI, thus giving spurious high measurements of SI decrease.
To avoid this: Excluded all nodules smaller than 8 mm from CS.Be careful when performing measurements to avoid adrenal margins.
Radio-isotope Scanning Based on the uptake and accumulation of radiotracers
(radio-cholesterol) in functioning adrenal tissue.
Anatomical localization and functional characterization.
The widespread application of adrenal scintigraphy is limited by the lack of experienced nuclear medicine center.
I131 labeled cholesterol analog can detect functional adrenocortical tumors.
Labeled guanethidine analog (MIBG) can detect functional adrenomedullary tumors.
Radio-isotope ScanningAdenomas (hypersecreting or nonhypersecreting) show radiocholesterol uptake and so appear as “hot” nodules.
Malignant tumors (primary or secondary) appear as “cold” nodules.
Therefore, adrenal masses can show different patterns of uptake depending on nature.
Radio-isotope ScanningLimitations:
Masses less than 1.5 to 2 cm in diameter and large tumors with extensive tumoral necrosis and/or hemorrhage may not show sufficient MIBG uptake for visualization.
False negative results also may be due to drugs that interfere with uptake.
PET and PET-CTPositron emission tomography (PET) is a promising imaging modality in oncology to measure noninvasively biochemical and/or physiological processes in vivo.
Combining PET and computed tomography (CT) providing useful structural and functional information for the detection and characterization of a variety of conditions affecting the adrenal gland.
The most common radiopharmaceutical is 18-fluoro-deoxy-glucose (FDG).
PET and PET-CTTracers are injected intravenously and incorporated into the organ of interest through the metabolism.
For FDG, which is an analog of glucose, the metabolic process is glycolysis.
Malignant lesions are known to be associated with enhanced glycolysis, and therefore accumulate FDG
PET and PET-CTAdvantages:
High sensitivity for detecting malignancy.
Disadvantages:16% of benign adrenal lesions may be positive on PET.Cost and insufficient data to support their routine use (not recommend ).
Schlamp A et al. (2007) Recurrent adrenocortical carcinoma after laparoscopic resectionNat Clin Pract Endocrinol Metab 3: 191–195 doi:10.1038/ncpendmet0391
CT and fluorodeoxyglucose (FDG)-PET scans of the tumor before and after primary surgery
AngiographyArteriography and venography: used in the preoperative evaluation of large adrenal lesions.
However, due to the unique sensitivity of spiral CT and MRI scans, these invasive techniques have become obsolete.
Adrenal Venous SamplingVenous sampling may have a place when bilateral adrenal masses associated with endocrine hyperfunction……..to localize site of hypersecretion
An experienced interventional radiologist is required because the right adrenal vein can be difficult to catheterize.
Adrenal Biopsyis a reliable technique and is the standard for diagnosis of adrenal pathologic conditions that cannot be accurately characterized with CT, MR imaging, or PET and in whom accurate staging is mandatory.Safe procedures with a high degree of accuracy and a low complication rate.CT is the modality of choice for guiding adrenal biopsies. Axial technique with a cutting core needle is useful.
Adrenal BiopsyFine-Needle Aspiration Biopsy (FNAB):
Using either CT or ultrasound guidance.Cannot differentiate between an adrenal cortical carcinoma and an adrenal adenoma. It can distinguish between an adrenal tumor and a metastatic tumor so used when there is a suspicion of cancer outside the adrenal gland. Invasive produces causing significant morbidity. Complications such as pneumothorax, septicemia, and hemorrhage have been reported in 8% to 13% of cases.Pheochromocytoma should always be excluded before attempting FNA biopsy of an adrenal mass.
Differential Diagnosis of
Adrenal Masses
Anatomical Classification
Classification by Nature
Bilateral Lesions
Fat-containing Adrenal Masses
Fat-containing adrenal masses can be classified into two main types:
1. those that contain intracellular fat (eg, adenoma)
2. and those with macroscopic fat (eg, myelolipoma).
Mass DiscoveryAdrenal masses are discovered by the following methods:
1) Adrenal masses were found incidentally )Incidentalomas) on abdominal sonography, CT or MRI done for non-related complaints such as abdominal pain, mass, vomiting and loss of weight.
2) Adrenal masses were found during examination for an extra adrenal 1ry malignant tumor.
3) Adrenal masses were found during the work up for endocrine and clinical manifestations raising the suspicion of adrenal affection such as hypertension, headache, muscle weakness, hypokalemia, elevated plasma aldosterone, suppressed plasma renin activity, paroxysmal attacks of hypertension and elevated urinary 24 hour VMA.
Imaging Appearance of Adrenal Masses
AdenomaMost common adrenal tumor.
Arise from the adrenal cortex
Characterised by the presence of intracellular lipid.
Lipid rich 70% and Lipid poor 30%.
80% are non-functioning.
AdenomaCT:
Small < 4 cm.Well-defined margin.Ovoid or rounded in shape.Homogenous densityCalcification and hemorrhage are rare.Lipid rich adenoma>10 HU.Unenhanced CT is unable to characterize lipid-poor adenomas<10 HU.Enhanced and delayed CT with APW and RPW has high sensitivity and specificity in distinguishing lipid poor adenomas.
Adenoma
MRI:Isointensity with liver on both T1 and T2W.
Chemical shift imaging is the most reliable technique for diagnosing adrenal adenoma with loss of signal intensity on out-of-phase images.
Uniform enhancement with contrast enhanced images is typical of adenomas.
MyelolipomaBenign neoplasms that composed of mature adipose cells and hemopoietic tissue in varying proportions.Most tumors are hormonally inactive. Mostly discovered accidentally. The most common symptom is pain. Usually found in the adrenal gland.Extra-adrenal sites especially presacral but also retroperitoneal or pelvicVary considerably in size from 1 cm to 30 cm
MyelolipomaUsually easy to recognize by large amount of mature fatCalcification in 20%The fatty component is evident and characterized on CT scans by low-density and inhomogeneous. On MRI, the fat appears hyperintense on T1WI and intermediate on T2WI. Loss of signal intensity of the fatty component on Fat-Suppressed Technique
Axial T1 MRI Axial T1 with Fat Suppressed Technique
Adrenal Cyst
Adrenal Cyst
Adrenal Cyst
Simple Cysts
Simple Cysts
Coronal T1 MRI T2 Coronal T2 MRI
Pseudocysts Pseudocysts typically arise after an episode of adrenal
hemorrhage and do not have an epithelial lining.
Have a complicated appearance on MR images, manifesting with septations, blood products, or a soft-tissue component secondary to hemorrhage or hyalinized thrombus.
Peripheral curvilinear calcification may be present.
Coronal T2 MRIAxial T1 with Contrast
Lymphangioma
Low signal intensity at T1-weighted imaging
Adrenal HemorrhageIt may occur spontaneously or may be the result of anticoagulation or trauma. Adrenal hemorrhage can be bilateral or unilateral. When adrenal hemorrhage is bilateral, the cause is usually associated with anticoagulation therapy or a blood dyscrasia; less commonly, it is associated with the stress of surgery, sepsis, or hypotension; and rarely, it is caused by trauma.Unilateral adrenal hemorrhage is usually caused by blunt abdominal trauma, adrenal vein thrombosis. It may occur into a preexisting neoplasm, necessitating surgical exploration if follow-up imaging does not show a nearly normal adrenal gland.
Adrenal HemorrhageCT:
Acute or subacute adrenal hemorrhage typically has an unenhanced attenuation value of 50-90 H. Follow-up studies show diminution in size of the adrenal mass with a gradual decrease in the attenuation value. The high attenuation value of a recent adrenal hemorrhage is usually readily apparent on unenhanced CT, but is indistinguishable from a solid adrenal neoplasm on contrast enhanced CT. Detection of an adrenal mass on contrast-enhanced CT after trauma is usually assumed to result from a hematoma, but an unrelated adrenal neoplasm can be excluded only by unenhanced CT or serial follow-up CT.
Adrenal HemorrhageMR imaging:
In the acute phase, a signal loss is observed on T1 and T2 images due to the presence of deoxyhemoglobin. In the subacute phase, hemorrhage have a high signal intensity, which reflects the presence of methemoglobin, on T1-weighted images.In chronic phases, the intensity on both T1 and T2 images is increased due to calcification and hemosiderin deposition.
Adrenal HemangiomaA rare benign tumor. Composed of closely adjacent vascular channels lined with a single layer of endothelium. Does not produce adrenal hormones.The most are large when found as an incidental finding.Hemangiosarcomas occur but are even less common.
Adrenal Hemangioma
CT:Large well-defined masses.
Soft tissue density on unenhanced images and exhibit inhomogeneous enhancement.
Most hemangiomas are calcified, either from phleboliths in the tumor or from previous hemorrhage.
Adrenal HemangiomaMRI:
A hypointense appearance relative to the liver on T1-weighted sequences.
Central hyperintensity may be seen because of hemorrhage.
On T2-weighted images, they are hyperintense.
Peripheral enhancement that persists on delayed images is characteristic.
Granulomatous DiseaseTuberculosis, histoplasmosis, and other granulomatous diseases are usually bilateral but often asymmetric.
Uncommon.
Should be considered in the differential diagnosis of incidental bilateral adrenal masses in the absence of a primary neoplasm or coagulation abnormality.
Granulomatous DiseaseCT findings are nonspecific and can include soft-tissue masses, cystic changes, calcifications, or a combination of these findings.
Biopsy is needed to confirm the diagnosis and identify the responsible organism.
Adrenal AbscessTypically encountered in the newborn as a complication of neonatal adrenal hemorrhage.
They are exceptional in adults and are secondary to hematogeneous spread or infection of adrenal hematoma.
Diagnosis is suggested by an abnormal mass projected in the anatomical location of the adrenal gland, usually associated with a septic condition.
Adrenal AbscessUltrasound, CT scan and MRI are all helpful in describing the lesion.
Early images can be misleading as the abscess can mimic a renal or adrenal tumor, but imaging follow-up will demonstrate a rapid growth and liquefaction of the mass.
Percutaneous aspiration may be useful in establishing an accurate diagnosis and is essential for a conservative approach.
Adrenal HyperplasiaOften seen in patients with Cushing syndrome and less commonly in Conn’s disease.
The hyperplasia may be diffuse or nodular and typically is bilateral.
On CT and MRI, the attenuation and signal intensity of hyperplastic adrenal glands are usually similar to that of the normal adrenal gland, although non-contrast attenuation could be lower in some cases.
Adrenal HyperplasiaThe signal intensity may also decrease on out-of-phase pulse sequences compared to in-phase pulse sequences, especially in patients with adenomatous cortical nodules.
Bilateral cortical hyperplasia is seen in 45% of patients with Cushing syndrome, whereas nodular cortical hyperplasia is seen in only 3% of these patients.
CT showing bilateral adrenal nodular hyperplasia
Adrenocortical CarcinomaRare malignancy.
Women: men 5:1
Age: 30 – 70 and may occur in childeren.
Large size
Can manifest as a hyperfunctioning mass causing Cushing or Conn syndrome.
Other manifestations include an abdominal mass and abdominal pain.
Adrenocortical Carcinoma
CT:Irregular shapeInhomogeneous density (central necrosis)>4 cm, unilateral and calcifyHigh unenhanced CT (>20HU)Delayed contrast washout Absolute contrast washout < 60 %Evidence of local invasion or metastasis.
Adrenocortical CarcinomaMRI:
Hypointense compared with liver on T1WI.High to intermediate intensity on T2WI.
PET:High standard uptake value (SUV) on FDG-PET-CT study.
PheochromocytomaCatecholamine-secreting tumor arising from chromaffin cells of adrenal medulla or extraadrenal ectopic tissue (paraganglioma).
The cause of hypertension in less than 1% of the hypertensive population.
Clinical symptoms: Headache, Sweating, Tachycardia
Part of syndromes: MEN II, NF, VHL, Sturge Weber.
Rule of 10’s: extra-adrenal, malignant, bilateral, extra-abdominal, familial, pediatric, no BP elevation.
PheochromocytomaThe diagnosis of pheochromocytoma is clinical and laboratory by measurement of 24 hours urine catecholamin level or plasma free metanephrine level.Most commonly benign, being malignant in 10% of patient.Benign lesions can be locally invasive into the IVC and renal veinIt is difficult to differentiate benign from malignant pheohromocytoma histologically Malignancy is usually established by local invasion or metastases.The most common site of metastasis include bone, liver, lungs and nodes.
PheochromocytomaCT:
A well-defined, rounded or oval hypervascular soft-tissue density masses frequently with central necrosis.2 to 5 cm in diameter.Homogeneous or heterogeneous density.Solid or cystic.CalcificationIncreased attenuation value on unenhanced CT (more than 20 HU).Marked enhancement after intravenous contrast material.Injection of ionic contrast medium can precipitate hypertensive crisis in some patients.Delayed contrast washout.Absolute contrast washout <60 %.
PheochromocytomaMRI:
The imaging procedure of choice.Hypointense on T1WIs.Characteristically hyperintense on T2-WIs (light bulb sign). Often have a heterogeneous appearance due to the presence of cystic regions, necrosis, and fibrosis.No signal loss on out-of-phase chemical shift images.MR angiography useful to delineate the anatomic relationships between adrenal tumors and vascular structures.
Light Bulb SignThe light bulb sign of an adrenal pheochromocytoma is MRI feature of this tumour. This refers to marked hyperintensity seen on T2 weighted sequences however this finding is neither sensitive nor specific and pheochromocytomas are more often heterogeneous with intermediate or high T2 signal intensity.
The light bulb sign of a hepatic haemangioma is a feature than can be seen on MRI imaging with a classic hepatic haemangioma. This refers to marked hyperintensity seen on heavily T2 weighted sequences that has been likened to a glowing light bulb.
The light bulb sign in posterior shoulder dislocation: refers to the abnormal AP radiograph appearance of the humeral head. When the humerus dislocates it also internally rotates such that the head contour projects like a light bulb when viewed from the front.
Axial T1 in Phase MRIAxial T1 out of Phase MRI
Contrast-enhanced Image
PheochromocytomaRadio-isotope:
113I-MIBG scintigraphy localizes pheochromocytoma as focal increased adrenal uptake with high sensitivity and specificity.
PET-CT:Studies have evaluated the use of PET in pheochromocytoma, but this has not yet achieved widespread use. FDG PET-CT can localized pheochromocytomas
Axial 18-FDG PET-CT image shows focal, marked uptake in right adrenal pheochromocytoma.
Adrenal MetastasisThe adrenal glands are a common site of metastatic disease.
The most common neoplasms with adrenal metastases are carcinomas of the lung and breast , melanoma and renal cell carcinoma.
In general, the adrenal lesion is part of the clinical picture of diffuse metastatic disease.
Usually bilateral but may also be unilateral.
Adrenal MetastasisThe CT and MR imaging features are nonspecific.
Small metastases are often homogeneous on contrast-enhanced CT or MR imaging, whereas large metastases often have local regions that appear heterogeneous as a result of necrosis, hemorrhage, or both.
Calcification is rare in adrenal metastases.
Adrenal LymphomaPrimary lymphoma of the adrenal glands is rare
Secondary involvement when other retroperitoneal lymphoma is present is seen more commonly among patients with non-Hodgkin's lymphoma than Hodgkin's disease.
Involvement is often bilateral and other retroperitoneal disease is usually present.
Adrenal LymphomaCT appearance:
Discrete masses or diffuse involvement of the gland in which the shape of the gland may be maintained.
There may be extensive retroperitoneal tumor that engulfs the adrenal glands, making them difficult to identify.
Mild post-contrast enhancement.
Adrenal Lymphoma
MR imaging: Low signal on T1WIs.
Heterogeneous hyperintense on T2WIs.
Adrenal lymphoma in a 67-year-old man with an adrenal mass. Imaging was performed for diagnosis and staging. Axial arterial phase (a) and coronal arterial phase volume-rendered (b) CT images show an 11-cm mass in the left adrenal bed. The mass invades the left hemidiaphragm, encases the celiac and renal arteries, and displaces the aorta. The mild degree of organ displacement despite the size of the mass and the infiltrative appearance are suggestive of lymphoma; the diagnosis was confirmed at core biopsy.
NeuroblastomaThe 2nd most common pediatric abdominal mass (after Wilms tumor).
5%–15% of all malignant tumors in children
Arises from the neural crest in the adrenal medulla or along the sympathetic chain.
Calcification is present in 85% of the lesions.
NeuroblastomaCT:
Large mass, often extending across the midline to engulf and displace the aorta anteriorly. Irregularly shaped, lobulated and unencapsulated.Invade adjacent organs or encase adjacent vessels.Inhomogeneous owing to tumor necrosis and hemorrhage. Coarse amorphous mottled peripheral calcification in about 85% of cases at CT.Heterogeneous contrast enhancement is usual.
NeuroblastomaMRI:
Heterogeneous low signal intensity on T1WIs.High signal intensity on T2WIs.Heterogeneous enhancement.Areas of intratumoral hemorrhage typically have high signal intensity on T1WIs.Cystic changes have high signal intensity on T2WIs.Is the preferred modality for investigating intraspinal extension of primary tumor (the so-called dumbbell neuroblastoma)
Dumbbell appearance of spinal tumors Refers to a tumor which has both a
component within the canal and a component in the paravertebral space linked by tumor traversing the neural exit foramen.
The appearance can be seen in:Spinal nerve sheath tumoursspinal schwannoma spinal neurofibromaspinal ganglioneuroma
NeuroblastomaSpinal meningioma
Contrast-enhanced CT shows a large retroperitoneal neuroblastoma with a very irregular lobulated border that surrounds vessels and has displaced the right kidney. The interface with the left renal cortex is indistinct and there is tumor invasion into the left renal hilum.
Coronal unenhanced T1-weighted MR image (a) and axial T2-weighted MR image obtained with inversion recovery (b) show a right adrenal tumor. The tumor is predominantly hypointense on the T1-weighted image and has areas of high-signal-intensity hemorrhage (arrow in a). The tumor is hyperintense on the T2-weighted image.
Coronal unenhanced T1 MRI Axial T2 MRI
GanglioneuroblastomaIntermediate in malignancy between that of neuroblastoma and ganglioneuromaArise from the neural crest.Are smaller and more well defined than neuroblastoma Demonstrates Intermediate signal intensity on T1WI and heterogeneously high signal intensity on T2WI, with heterogeneous enhancement after administration of contrast material.
-Right: Coronal T2-weighted image showing a large lobulated right adrenal mass with heterogeneous signal intensity in a 14-year-old child with elevated urinary catecholamines. -Left: Coronal T1-weighted image with contrast enhancement and fat saturation. The mass is poorly enhancing and separate from the right kidney. -Histologically this was a ganglioneuroblastoma.
T1-WI shows a heterogeneous mass with intermediate signal intensity
Neurogenic Tumor Neurogenic tumors: are the cause of approximately
90% of posterior mediastinal masses. They can be subdivided into three groups by their location and involvement of peripheral nerves or sympathetic chain.
Peripheral nerve sheath tumorSympathetic ganglia tumorParaganglioma
Peripheral nerve sheath tumors and paragangliomas are far more common in adults while the sympathetic ganglia tumors are more common in children.
Neurogenic Tumor Peripheral nerve sheath tumours
These tumors manifest as round paravertebral masses that span one or two vertebral bodies. They are homogenous, soft-tissue attenuation masses at CT and the commonest cause of posterior mediastinal and paravertebral masses. They may cause widening of the neural foramen and thickening of the adjacent posterior rib.
SchwannomaNeurofibromaMalignant peripheral nerve sheath tumour
Neurogenic Tumor Sympathetic ganglia tumors
These tumors tend to present as elongated paraspinal masses that span multiple vertebral levels. Intra-tumoral calcification is common.
Neuroblastoma - young childrenGanglioneuroblastoma - older childrenGanglioneuroma - children and adults
Neuroblastoma and ganglioneuroblastoma are most commonly seen in children and in a child they comprise the most common neurogenic tumour.
Neurogenic Tumor
Paraganglioma These tumors are similar histologically
to phaeochromocytoma and can be functioning or non-functioning.
Collision TumorsAre formed by coexisting lesions of different pathologic origins.
Manifest with atypical imaging appearances.
Represent a pitfall in anatomic staging as with CT alone, differentiation of benign from malignant tissue in an adrenal gland is difficult,
One of the principal advantages of PET-CT is its precise coregistration, which improves the detection of subtle disease.
(Top left): Contrast-enhanced CT scan shows a regular, ovoid mass of the right adrenal gland with a fatty component (-84 HU). (Top right): Coronal FLASH two-dimensional gradient-echo T1-weighted MR image shows a heterogeneous mass with some well-limited hyperintense areas (arrow). (Bottom left): T2-weighted MR image shows that these areas (arrow) have the same high signal intensity as retroperitoneal fat. (Bottom right): T1-weighted MR image obtained with fat suppression shows heterogeneous enhancement and the lipidic nature of the corresponding areas (arrow).
Collision tumor with associated myelolipoma and adenoma.
Imaging Work Up
Summary and Conclusion
Adenoma AdrenocorticalCarcinoma
Pheochromocytoma Metastasis
Size < 3 cm diameter >4 cm diameter >3 cm diameter Usually <3 cm
Shape Round, smoothMargins
Irregular, no clear margins
Round/oval, clear margins
Oval/irregular, unclear margins
Texture Homogenous Heterogenous, mixed densities
Heterogenous, cystic Heterogenous, mixed densities
Lateralize Solitary, unilateral Solitary, unilateral Solitary, unilateraly Bilateral
CT Attenuation <10 HU >25 HU >25 HU >25 HU
CT Washout at 10 minutes
>50% <50% <50% <50%
T2 MRI Appearance (compare to liver)
= + +++ +
Necrosis, Ca, hemorrhage
Rare Common Common Occasional
Growth rate Slow Rapid Slow Variable
Long Case 43 year-old male
Three months history of episodic palpitations and chest burning, radiating to his back
Past medical history: hypertension, dyslipidemia
Social history: Alcohol abuse, non-smoker
Review of system: No fever, no chills, no changes in his weight, no temperature intolerance, no visual difficulties, no headaches, no difficulty swallowing, no cough, no shortness of breath, no leg edema, no GI or GU symptoms, no skin rashes.
Physical Exam: Regular apical pulse of 110
A portable AP chest radiograph was obtained in the ED to rule out any acute cardiopulmonary processes.
•Cardiomediastinal and hilar contours are normal.•Lungs are clear with out consolidation or pulmonary edema. •No pleural effusion.•Osseous structures are unremarkable.
Heavy metal/calcific opacity superimposed the RUQ
•What are the findings?
Patient Presentation: 5 Months Later More frequent palpitations with chest pain
Episodic hypertension
Complaint of night sweats and headache
EKG unchanged
Due to complaints of upper abdominal/lower chest pain, chest radiographs were obtained to rule out any acute cardiopulmonary processes.
Unchanged amorphous calcific density
Where is this lesion?
5-month Follow-up Chest Radiograph
• In the liver?• In the gallbladder?• In the bowel?• In the kidney?• In the adrenal?• In the connective
tissue?
• Let’s look at the lateral chest radiograph.
The lesion is posterior, possibly retroperitoneal.It does not seem to involve the liver or gallbladderThe lesion may be in the right adrenal, right kidney, bowel, or connective tissue
Differential Diagnoses for the Patient’s Posterior Calcific LesionBased on Organs:• Right Adrenal gland
– Pheochromocytoma– Adrenocortical carcinoma– Myelolipoma– Prior hemorrhage, trauma, infection– Metastases (calcifications rare)
• Right Kidney– Renal cell carcinoma– Hemorrhagic cyst– Prior infarction, laceration
• Bowel– Gastrointestinal stromal tumor
Not Organ-related: Liposarcoma
The patient’s history of episodic tachycardia, diaphoresis, headache and hypertension combined with findings on chest radiographs and ultrasound suggest pheochromocytoma and further workup is indicated.
Preliminary Diagnosis
Both lesions demonstrate avid peripheral enhancement. Both appear heterogeneous. The larger mass (left) shows central calcifications.
Our Patient: Contrast-enhanced Axial CT Images
T1 weighted, pre-contrast
T1 hypointense relative to skeletal muscle
The periphery avidly enhances.The central area of necrosis
demonstrates no uptake.
T1 weighted, post-contrast, arterial phase
A 45 years old female patient with history of ovarian carcinoma under follow up.
CT Examination
CT Examination:Axial and coronal non-enhanced CT images showed a well-defined hypodense left adrenal mass with attenuation value (5 HU). Axial and coronal contrast- enhanced CT images acquired after 1 minute showed diffuse homogeneous enhancement of the left adrenal mass with increased attenuation value reaching (56 HU). Axial and coronal delayed contrast-enhanced CT images acquired 15 minutes later showed significant washout of contrast with reduction of attenuation value reaching (20 HU).
The non-contrast CT attenuation value was (5 HU), the APW was (71%) and RPW was (64%). These values were consistent with lipid-rich adenoma.
MRI Examination
MRI Examination: Axial T1, axial and coronal T2-weighted MR images showed a well-defined left adrenal mass, displaying isointense signal relative to spleen on T1 and T2WIs.Axial and coronal gradient-echo in-phase& K, M) Axial and coronal out of-phase MR images showed significant visual signal loss between in-phase and out of-phase images (qualitative assessment).
By quantitative assessment of chemical shift images, the ASR was (0.31) and SII was (42%).
MRI findings were consistent with adenoma
CT examination
A 62 years old male patient presented to the orthopedic clinic by pathological fracture of RT femur
CT Examination: Axial non-enhanced CT image showed a well-defined hypodense right adrenal mass with attenuation value (48 HU). Axial and coronal contrast enhanced-CT images obtained after 1 minute showed diffuse heterogeneous enhancement of the mass with increased attenuation value (74 HU). Axial delayed contrast enhanced-CT image obtained after 15 minutes showed no significant washout of contrast with attenuation value (62 HU).
The APW was (46%) and the RPW was (16%).Based on the CT study, these values matching with non-adenoma
MRI examination
MRI Examination: done after 6 month
Axial T1, axial and coronal T2-weighted MR images showed the right adrenal mass with central area of necrosis. Axial gradient-echo in-phase and out of-phase MR images showed no significant visual signal loss between in-phase and out of-phase images. (Qualitative assessment).
By Quantitative assessment of chemical shift images, the ASR was (1.08) and SII was (15.8%). These MRI findings were matching with non-adenoma
Biopsy was done and Histopathology revealed Adrenocortical Carcinoma.
That’s enough for now!
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