High-pitch low-dose abdominopelvic CT with tin-filtration technique for detecting urinary stones.

OBJECTIVES

To evaluate urinary stone detection, radiation exposure, image quality, breathing-motion artifacts, and scanning time with high-pitch tin filter-based abdominopelvic CT.

METHODS

Sixty-three consecutive patients with urolithiasis underwent non-enhanced abdominopelvic CT with both regular (120 kV, pitch 0.6) and low-dose (Sn150kV, pitch 3.0) protocols on a third-generation dual-source CT. Stone characteristics, image noise (SD), signal-to-noise ratio (SNR), subjective image quality on a 5-point likert scale breathing-motion artifacts, and scanning time were evaluated. Volume CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED) were compared.

RESULTS

A total of 157 urinary stones were detected by regular protocol; 154 were correctly identified by low-dose protocol with an overall detection rate of 98.1%. No significant differences were observed in SD, SNR, or subjective image quality between two protocols (P > 0.05). Compared to regular protocol, CTDIvol and ED were 56.6% (7.19 vs. 3.12 mGy, P < 0.001) and 55.6% (5.25 vs. 2.33 mSv, P < 0.001) lower; scanning time was 89.5% (7.9 vs. 0.83, P < 0.001) shorter; and breathing-motion artifacts were fewer (8 vs. 0 patients) with low-dose protocol.

CONCLUSIONS

High-pitch abdominopelvic CT with Sn150kV substantially reduced radiation exposure and scanning time, while maintained stone detection and image quality and prevented breathing-motion artifacts.