Evaluation of Imaging Abnormalities of Ureter using MDCT Urography

Abstract

Introduction: Computed Tomography (CT) has become the primary imaging modality for assessment of excretory system. It has essentially replaced intravenous urography as the first line imaging modality. The major advantage of CT-urography is not only in its superior visualisation of the urinary tract, but also assessment of adjacent structures and other organs of the abdomen where intravenous urography fails. Aim: The aim of this study is to identify the pattern of pathologies involving the ureter and provide a systematic approach to interpret such abnormalities at CT urography. Materials and Methods: A prospective study was done using data gathered from 100 patients over a period of six months who were referred for contrast enhanced CT examination of the KUB region for suspected urinary abnormalities between age group of 18-70 years. Non-contrast, cortico-medullary, nephrographic and excretory phases were obtained and analyzed for ureteral abnormalities. Findings were recorded and analyzed using descriptive statistics. Results: The mean age group of study subjects was 38.4±14 years. The imaging findings in our study were basically classified into five groups – congenital abnormality, filling defects, ureteral dilatation, narrowing and deviation in course. Ureteral duplication was the most common congenital abnormality found in our study while calculi were the most common cause of filling defects. Ureteral obstruction due to various causes including calculi, clots, malignancy etc., was the predominant etiology of ureteral dilatation while strictures were the commonest etiology of ureteral narrowing. Two cases of deviation in course of the ureter were reported, one due to retroperitoneal fibrosis and the other due to abdominal aortic aneurysm. Conclusion: This study outlines the most common findings in patients referred for contrast enhanced CT scans for KUB and their imaging findings. A systematic approach to interpreting ureteral abnormalities includes assessment for congenital abnormalities, filling defects, dilatation, narrowing, and deviation in course. Because of the prevalence of ureteral abnormalities, it is vital for radiologists to recognise the varied appearance of ureteral disease at CT-urography.

Keywords

• calculi
• clots
• congenital abnormality
• ureteral dilatation