Coronal reconstruction of unenhanced abdominal CT for correct ureteral stone size classification.

Purpose: To determine whether size measurement of a urinary calculus in coronal reconstruction of computed tomography (CT) differs from stone size measured in the axial plane, and whether the difference alters clinical decision making.

Methods: We retrospectively reviewed unenhanced CT examinations of 150 patients admitted to the emergency room (ER) with acute renal colic. Maximal ureteral calculus size was measured on axial slices and coronal reconstructions.