Tests for acute flank pain
What is the test of choice for the examination of patient with acute flank pain?
Unenhanced CT scan of the abdomen and pelvis is the preferred imaging modality, because virtually all stones are of sufficient attenuation to be detected on CT.
The principle exception are stones consisting solely of indinavir sulfate (Crixivan, Merck, Rahway, New Jersey).
In addition to direct visualization of a ureteral stone, secondary signs of obstruction on CT are commonly present. Unenhanced CT can also reveal many other causes of acute flank pain unrelated to the urinary system, such as pelvic masses, appendicitis, and diverticulitis.
Ureteral dilatation has a sensitivity of approximately 90% for use in making a diagnosis of acute ureteral obstruction.
Stranding of the perinephric fat and stranding of the periureteral fat both have sensitivities of approximately 85% but low specificity.