이중에너지단층촬영을 이용한 요로결석 분석과 임상적 의의: 예비 실험적 검사와의 비교

Abstract

Objective : The aims of this study are to predict compositions of renal stones with dual energy CT and to compare with pathologic results of preliminary experimental study.

Methods : Seventeen patients (male:female = 11:6, mean age = 64.7 years) among 256 patients treated for suspicious urinary stones were included in this study. Non-enhanced multidector CT (Aquilion one, Toshiba medical systems corporation, Japan) with dual energy were taken in all patients before operation. Attenuations of detected stones were measured on images taken from low energy (80 kVp) and high energy (135 kVp) by workstation. Uric acid and non-uric acid stones were categorized depneding on attenuation value using the result of in vitro phantom model. Extracted stones were analyzed by using spectroscopy (Fourier Transform Infrared Spectrometry, FT-IR) and the compositions of stones confirmed pathologically were compared with those of dual energy CT scans.

Results : Stones with attenuation ratios below 1.1 were predicted to be uric acid stones and those more than 1.1 were predicted to be non-uric acid stones based on result of preliminary experimental study. Extracted stones were analyzed as 7 uric acid stones and 10 non-uric acid stones. Each averages of attenuation ratios in uric acid stone and non-uric acid stone was 0.91 and 1.29, respectively. Compositions of all stones extracted surgically showed same results from those of CT scans with dual energy (sensitivity 100%). It was difficult to make differential diagnoses from various kinds of non-uric acid stones.

Conclusion : Dual energy CT scans is a promising and useful imaging modality to predict compositions of renal stones.