AUA 2019: Diuresis Enhanced Non-Contrast Computed Tomography for Kidney Stones (DRINK) for Enhanced Visualization of the Renal Collecting System

Chicago, IL ( Sung and colleagues at the University of California, Irvine report their initial experience with their novel pre-hydration protocol for non-contrast CT scans for kidney stones. They hypothesized that their DRINK protocol (pre-hydration with one-liter water and inducing diuresis with 20 mg of oral furosemide) would allow distension of the renal collecting system for better visualization on CT images.

Previous studies have shown that IV hydration and IV furosemide had successfully distended renal collecting systems. They prospectively randomized 20 patients undergoing non-contrast CT scans for kidney stones. A prerequisite for enrollment was that the patient needed to have had a previous non-contrast CT scan that would act as their own historical control. Each patient was instructed to follow the DRINK protocol.

The patients’ prior CT scan and their new DRINK CT scan were then blindly evaluated by three endourologists who measured specific anatomic segments of the renal collecting system (upper pole infundibulum, renal pelvis, and lower pole infundibulum). Sung and colleagues also created 3D renderings of the CT scans.

Only 13 of 20 patients completed the DRINK protocol in its entirety and among those 13 patients, there was a 17-37% increase in the widths of the anatomical segments of the collecting system. From their 3D renderings, between the non-DRINK 3D models and DRINK 3D models, there was on average a 63% increase in the volumes of the collecting system.

It is interesting to see that there was a statistically significant increase in the volumes over 60%. Although this study mainly seems like a proof of concept, there may be clinical implications for the future. For example, this protocol may have some utility for preoperative planning for stone procedures. Nevertheless, this pilot study proved a statistically significant increase in distensions of the renal collecting systems with the DRINK protocol and a larger, prospective randomized trial would be of interest.

Presented and written by: John Sung, Department of Urology, University of California-Irvine, @JohnM_Sung at American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois