11th May 2026, NIA Diagnostic Imaging

loin/flank pain

When you suspect renal colic in a patient presenting with loin or flank pain, you have a number of different scans you can order to explore the diagnosis. It could be an ultrasound of the kidneys or a CT scan of the KUB (kidneys, ureter and bladder). Which one should I order?

Renal colic commonly presents with acute flank pain radiating to the groin, often due to urolithiasis. Other symptoms often include severe, fluctuating pain in the back, lower abdomen, frequently accompanied by nausea, vomiting, blood in the urine, and frequent or painful urination. Imaging is essential to confirm diagnosis and guide management and a non-contrast CT scan of the kidneys, ureters and bladder (CT KUB) is considered the gold standard examination for diagnosis.