Present-day imaging of patients with renal colic

In the past decade arternatives to urography have been proposed for the stu dy of patients with renal colic. In 1992 it was suggested to replace urogra phy with KUB and ultrasonography. In 1993 the combination of KUB and ultras onography followed by urography in unresolved cases was proposed and, in 19 95, it was suggested to replace urography with unenhanced helical CT (UHCT) . This article illustrates the contribution of UHCT to the study of patient s with renal colic and analyses advantages and shortcomings of the techniqu e compared with other diagnostic approaches. Diagnostics of the patient wit h renal colic is based on the detection of direct and indirect signs which allow identification of not only the calculus, with a sensitivity of 94-100 % and accuracy of 93-98 % according different authors, but also other sign s that can serve to guide patient management and evaluate long-term prognos is. Unenhanced helical CT has the capability to detect extraurinary abnorma lities which present with flank pain and mimic renal colic. The examination technique affects the quality of the images and therefore diagnostic accur acy as well as the dose to the patient. With regard to setting parameters, the choice of thickness and table feed should be guided by numerous factors . Multiplanar reconstruction is indicated in the study of the entire ureter course to identify the exact site of the calcification for the urologist t o perform an evaluation similar to that obtained by urography. Many authors consider UHCT to be a valuable tool for suggesting the best therapeutic ap proach. Among these there are also urologists. The evaluation is based on t he stone detection, its size and level in the urinary tract. Cost analysis shows that the cost of UHCT is equal to or inferior to the cost of urograph y. With regard to the dose, different data are reported in the literature. A high pitch (more than 1.5) and a thin collimation (3-mm thickness) are go od compromise between quality and dose which can be compared to the dose of normal urography. What is to be done if helical CT is not available? If he lical CT is not available, plain film plus ultrasonography should be consid ered. This approach does not solve all the cases; in unresolved cases urogr aphy is indicated. It should also be noted that US has a good sensitivity i n detecting other conditions such as biliary lithiasis, acute pancreatitis, acute appendicitis and abdomino-pelvic masses which are responsible for pa in that mimics renal colic. In conclusion, IVU should not have any more the priority in investigating the patients with renal colic. Helical CT should be the first choice in imaging a patient with renal colic. If this techniq ue is not available, plain film and ultrasonography should be considered ad ding urography in unresolved cases.