Which of the following is the most sensitive imaging modality for the diagnosis of ureteric stones in a patient with acute colic?

The most sensitive imaging modality for diagnosis of ureteric stones in a patient with acute colic is non contrast CT scan of abdomen. It has a sensitivity and specificity greater than 90%. Advantages of using it are: It avoids problems due to intravenous contrasts, allows diagnosis of non urological pathology. Disadvantage: It is associated with significant exposure to ionizing radiation (2.5cGy). Ref: Emergency Surgery By Adam Brooks, Page 127; SRB's Manual of Surgery By Sriram Bhat, 3rd Edition, Page 959