Xiaohu Li MD, Presenter: Nothing to Disclose

Bing Liu MD, Abstract Co-Author: Nothing to Disclose

Yu Yongqiang MD, PhD, Abstract Co-Author: Nothing to Disclose

To prospectively assess the accuracy of Single x-ray Single-source 64 slice CT Scanner technique that uses two consecutive scans for differentiating uric acid (UA) and non-uric-acid (No-UA) Kidney stones

52 patients (24 males and 28 females) undergoing clinically-indicated dual energy spectral CT( DESCT，fast kilovolt-age switching) to differentiate UA and No-UA Kidney stones were enrolled in this IRB-approved study. Immediately following the DESCT scan, each patient was scanned on a single-source 64 slice CT scanner (SS)with two consecutive scans (80 and 140 kVp) over a scan range limited to where stones had been identified using DESCT. UA and No-UA stones were differentiated using Advantage Workstation 4.5 (GE Healthcare, Milwaukee, WI, USA).. The accuracy of stone classification for stones >1.5mm in diameter was calculated using the results from the DESCT scanner as the reference standard.

A total of 364 stones were identified in DS exams (32 UA and 332 No-UA). Average stone diameter was 4.1 ± 1.4 mm (range 1.5 to 15.6 mm). Among these stones, SS exams detected 82 UA and 282 No-UA stones. Overall sensitivity and specificity for identifying UA stones were 67% and 85%. For stones ＞4 mm (37 UA and 235 No-UA on SS exams, 26 UA and 266 No-UA on DESCT exams), sensitivity and specificity were 93% and 96%. Image quality of the SS exam was similar to or slightly better than that of the DESCT exam

Differentiation of UA and No-UA Kidney stones is feasible by using two consecutive scans. UA stones could be identified using a SS CT scanner with an accuracy of 96% for stone sizes >4mm. 

Knowledge of the composition of urinary tract stones is a fundamental part of the preoperative patient evaluation, and this information influences treatment plans and recurrence prevention. UA stones may be treated with urinary alkalinization as a first-line treatment, with surgical treatment being reserved for stones that do not respond to medical therapy.Accurate Differentiation of UA and No-UA using SS scanners may increase availability for this technique, which is clinically useful in identifying patients with medically treatable stones. 

Li, X, Liu, B, Yongqiang, Y, Differentiation of Uric Acid and Non-uric-Acid Kidney Stones Using a Single-source 64 Slice CT Scanner: Initial Clinical Experience.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003787.html