Unenhanced CT in the evaluation of renal/ureteric colic

Abstract

Unenhanced CT of kidneys, ureters and bladder (CTKUB) is now the recommended imaging modality in the investigation of patients with acute renal or ureteric colic. This review aims to illustrate the normal urinary tract anatomy to assist imaging interpretation, outline the CTKUB imaging technique and image review at the Picture Archiving and Communication System workstation, discuss the pertinent imaging findings such as the direct signs, for example, soft tissue rim sign and comet tail sign, as well as secondary indirect signs such as pale kidney sign, nephromegaly, hydronephrosis, hydroureter and perinephric stranding or edema on the CTKUB for the diagnosis. Imaging pitfalls in the interpretation will be illustrated and discussed, for example in the presence of a ureteral stent and optimal image interpretation with wide windowing on CT. In addition, the discussion will also include the use of scout radiograph, the importance of detecting extraurinary pathology during CTKUB examination and explore Randall...