non-contrast enhanced multidetector computed tomography versus plain x-ray urinary tract film in...

NON-CONTRAST ENHANCED MULTIDETECTOR NON-CONTRAST ENHANCED MULTIDETECTOR

COMPUTED TOMOGRAPHY VERSUS PLAIN X-RAY COMPUTED TOMOGRAPHY VERSUS PLAIN X-RAY URINARY TRACT FILM IN ACUTE RENAL PAINURINARY TRACT FILM IN ACUTE RENAL PAIN

Hazem A. Youssef*, Mohammad K. Omar*, Hossam A. Hazem A. Youssef*, Mohammad K. Omar*, Hossam A. Youssef*, and Hassan A. AbolellaYoussef*, and Hassan A. Abolella****

**Radiology Department, Faculty of Medicine, Assiut UniversityRadiology Department, Faculty of Medicine, Assiut University..****Urology Department, Faculty of Medicine, Assiut UniversityUrology Department, Faculty of Medicine, Assiut University. .

Patients with suspected urinary tract disease are often referred for multiple studies such as excretory urography (EU), ultrasound (US), CT or MRI. Multi-examination work-ups require much patient effort and are expensive. A single imaging test that comprehensively evaluates the urinary tract has advantages both in terms of convenience and cost (NOROOZIAN et al. 2004).

INTRODUCTIONINTRODUCTION

Patients often present to the urology or emergencydepartment with flank pain or colic due to ureteralcalculus. Because it provides fast results, unenhancedmultislice computed tomography (MSCT) has largely supplanted intravenous urography, and, in the United States, MSCT generally prevails as the standardexamination for detecting ureteral calculi (Wehrschuetz et al. 2009).

The objective of the current study is to evaluate the sensitivity, specificity, and overall accuracy of unenhanced MSCT in the diagnosis of calcuar and non calcular causes of acute flank pain compared with those of plain X-ray (KUB).

OBJECTIVEOBJECTIVE

Study PopulationA total of 160 consecutive patients (97 males and 63 females, median age 41.2 years, range 2-80) with suspected urinary calculi were included in this retrospective pilot study from January through September 2009.

PATIENTS AND METHODSPATIENTS AND METHODS

Imaging protocolUnenhanced MDCT images were acquired with a 64 detector row CT scanner VCT GE, Milwaukee, WI.Five-millimeter contiguous unenhanced axial CT images were obtained in a cephalocaudal direction from the diaphragm to below symphysis pubis. No oral or IV contrast was administered.IV diuretic (20mg furesemide) was routinely administered 15 minutes prior to scanning to maximally distend the collecting system, ureters and UB.

Scanning protocolScans were obtained with tube rotation time 0.8sec, pitch 0.984:1, table feed/gantry rotation 39.75mm, a tube voltage of 140 kVp and effective tube current-time product of 548mAs.

Image processingAll datasets were sent to a commercially available

workstation (ADW4.4). In all patients 5mm MPR images were obtained in addition to the following:

1) Thick slab MIP.2) Volume rendering (VR).3) Curved reformats for the ureters (CPR).

Image evaluation Two independent radiologists and a urologist

analyzed the images. The observers were asked to separately determine whether pyelocalyceal and ureteral calculi were present. They were instructed to document the location and size of each calculus using standard measurement devices. Non calcular causes of colic or associated abnormalities were individually assessed and documented.

When KUB films were not available digital scout or

scan projection radiographs in lieu of conventional radiographs were obtained.

Urinary calculi were detected in 10 patients referred after inconclusive IVU and in 8 patients with ureteric stents. In 2 patients with inconclusive IVU ureteric stricture was the alternative diagnosis.

RESULTSRESULTS

MDCT diagnosisMDCT diagnosis No. of patientsNo. of patients

Obstructing ureteric calculiObstructing ureteric calculi 9898

Ureteric strictureUreteric stricture 3232

Ureteric massUreteric mass 33

UB massUB mass 33

Retroperitoneal fibrosisRetroperitoneal fibrosis 22

Hydroureteronephrosis with no lesion Hydroureteronephrosis with no lesion identifiedidentified

33

PUJ obstructionPUJ obstruction 55

Non obstructive calculiNon obstructive calculi 110110

Acute appendicitiesAcute appendicities 55

Pelvic abscessPelvic abscess 11

NormalNormal 88

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100

120

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No. of stones/ patientNo. of stones/ patient No. of patientsNo. of patients

00 55

11 22

22 33

33 33

44 11

55 33

66 11

77 22

7-157-15 22

<<1515 11

TotalTotal 110110

REPRESENTATIVE CASESREPRESENTATIVE CASES

CPR and VR images showing 3 ureteric calculi and non obstructive lower calyceal calculus. Thickening of the ureteric walls and periureteric haziness

are also evident.

CPR VR

CPR VR

CPR and VR images showing non obstructive left lower calyceal calculus.

CPR VR

CPR and VR images showing obstructive lamellated pelvic calculus and non obstructive calyceal calculi.

MIP VRCPR

MIP, CPR and VR images showing obstructive middle ureteric calculus with faintly opacified obstructed PCS and ureter.

CPRVR

CPR and VR images showing calcific lower ureteric stricture with marked hydrouretronephrosis.

CPRVR

CPR and VR images showing incomplete douplex system of the left kidney with distal ureteric fusion and obstructing lower ureteric calculus

with marked hydrouretronephrosis.

Coronal reformatted images showing the 2 ureters with distal fusion.

CPR and coronal reformatted images showing obstructing middle ureteric calculus with marked hydrouretronephrosis, gas density within the PCS and stranded perirenal fat

indicating emphysematous pyelonephritis.

CPR images showing retroperitoneal mass entangling and medially displacing middle ureterswith bilateral hydrouretronephrosis diagnostic of retroperitoneal fibrosis.

Axial images showing the retroperitoneal mass entangling and medially displacing

middle ureters with bilateral hydrouretronephrosis.

CPR images showing left hydrouretronephrosis with stripping of the renal capsulesecondary to intramural calculus. Note bilateral non obstructive calyceal calculi.

CPR images showing right hydrouretronephrosis caused by a lower ureteric mass extending into the UB.

The CTU has become the radiologists most robust imaging tool for the evaluation of the kidneys, upper urinary tracts, and UB.Complete imaging of the kidneys and urinary tracts can be performed with MDCT. Studies are tailored to the clinical question and may be performed as noncontrast, combined non-contrast and post-contrast or post-contrast imaging studies only.

CONCLUSION AND RECOMMENDATIONSCONCLUSION AND RECOMMENDATIONS

Finally radiologists need to educate emergency room and referring physicians about the limitations of unenhanced CT scans, as it does not detect infarcts, pyelonephritis, small renal cell carcinomas, or small ureteral tumors.

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