Comparison of Hounsfield Unit and İntraoperative “GATA Scale” Score to Determine Requirement of DJ Stent Insertion in Ureteral Stone Treatment

Abstract

Objective:In this study, we aimed to determine the contribution of hounsfield unit (HU) measurement with non-contrast-enhanced computed tomography to the treatment of a single ureteral stone, and compare the value of HU and intraoperative “GATA scale” score in deciding for DJ stent placement in patients with a single ureteral stone.Materials and Methods:Ninety patients diagnosed with a single ureteral stone in our clinic between January 2018 and September 2018 were evaluated prospectively. We planned a new scale called “GATA scale” with three benchmarks. The validity and reliability of HU were compared with those of GATA scale score. Statistical significance was defined as p<0.05.Results:The mean stone volume at diagnosis was 245.29±23.9 mm3. The mean HU of ureteral stones was 1065.21±33.5. The mean total score according to GATA scale was 6.44±0.2. To determine the threshold value for factors affecting stent placement after lithotripsy, receiver operating characteristic analysis was performed for stone volume, laser duration, total energy to complete laser lithotripsy and GATA scale score and showed that the optimal thresholds were 164.01 mm3, 4.25 mins, 1004 W and 7.5, respectively.Conclusion:In clinical practice, GATA scale can be used in decision making for DJ stents placement. Stent placement following lithotripsy is recommended especially in patients with a stone volume of greater than 160 mm3 or total energy to complete laser lithotripsy over 1000 W or laser duration longer than 4 minutes or GATA scale score higher than 7.

Keywords

• ureteral stone
• hounsfield unit
• laser lithotripsy