Presentation
Bilateral flank pain with right-sided hydronephrosis on the ultrasound examination.
Patient Data
The proximal right ureter is seen coursing posterior to the inferior vena cava, then emerging to the right of the aorta and then passing anterior to the lower IVC and right iliac vessels. The ureter passing behind the IVC has a fishhook or S-shaped appearance and is associated with moderate proximal hydroureteronephrosis. The remaining right ureter is of normal calibre. There is a small radio-opaque calculus (3mm) at the left vesicoureteric junction without any significant proximal hydroureteronephrosis.
Case Discussion
CT scan findings are suggestive of a low loop circumcaval or retrocaval ureter (type 1), causing moderate proximal hydroureteronephrosis (grade 3).
No contrast passage is seen through the abnormal retrocaval segment of the right ureter on the initial excretory phase acquired in the supine position which was likely due to the compression by the IVC. This compression was partially relieved by putting the patient in a prone position, as is evident by the opacification of the distal right ureter on the repeated excretory phase in the prone position.
NB a multiphasic CT scan of the abdomen including the arterial phase was planned while using the bolus tracking technique; however, due to some technical issues, the scanner did not start in time and the arterial phase of the scan was skipped and even the portal venous phase of the scan was slightly delayed.
Case courtesy: Dr Mohammed Khalifa
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