Can the Hounsfield unit predict the success of medically expulsive therapy

Abstract

We investigate the predictability of medical expulsive therapy (MET) success with alpha blockers based on Hounsfield unit (HU) values and Hounsfield density (HD) values measured by computed tomography (CT) for distal ureteral stones. Between July 2011 and May 2012, 44 patients (19 female and 25 male) with 5- to 10-mm stones in the distal ureters were included in this randomized prospective study. Non-contrast CT examinations were performed in these patients. HU and HD values of stones were calculated. Doxazosine, 4 mg/day orally, was administered as a single dose to all patients for MET. Patients were divided into 2 groups. Group 1 included 18 patients (43.9%) with dropped stones with MET. Group 2 included 23 patients (56.1%) with no stone passage with MET. In Group 1, the mean stone size was 7.7 mm, the mean HU was 507, and the HD was 53.04/mm. In Group 2, the mean stone size was 8.25 mm, the mean HU was 625, and the mean HD was 61.54/mm. The HU and HD values in Group 2 were higher than in Group 1. However, there was no statistically significant difference (p = 0.85 and 0.93 for HU and HD, respectively). We found that HU and HD values cannot be used to predict the chances of success for MET. Although the sample size is appropriate for the study, further comparative studies involving more patients are warranted.