单能量成像及能谱曲线对胆囊等密度胆固醇结石的诊断价值

Diagnose Value of Single energy Imaging and Spectral Curve in Isodense Cholesterol Stone in Gallbladder

目的探讨单能量成像及能谱曲线对胆囊等密度胆固醇结石的显示价值。方法选取我院经临床证实而混合能量不能明确诊断的胆囊等密度胆固醇结石患者20例（计20枚结石），全部病例均行上腹部能谱平扫，采用GSIViewer软件进行单能量成像及能谱曲线分析，测量40～140 KeV共11组（每组间隔10KeV）图像的结石及胆汁的CT值，并计算结石及胆汁的能谱曲线的斜率，采用t检验进行统计学分析。结果混合能量下，17例结石呈等密度，3例呈稍高密度灶，结石CT值为（18．21±3．82）HU，胆汁CT值为（13．61±3．92）HU。单能量成像后，结石的CT值从40～140KeV依次升高，胆汁的CT值依次减低，70KeV组结石与胆汁的CT值间差异无统计学意义（t=1．57，P=0．129），其余各组差异均有统计学意义（P〈0．01），结石的能谱曲线斜率为-0．838±0．187，胆汁的曲线斜率为0．300±0．102，两者差异有统计学意义（t=-22．01，P〈0．01）。结论单能量成像及能谱曲线有助于显示常规CT不能显示的胆囊等密度结石。

Objective To explore the value of single energy imaging and spectral curve in the diagnosis of isodense cholesterol stone in gallbladder. Methods 20 patients with total 20 isodense gallstones, confirmed clinically but couldnt be diagnosed definitely by conventional CT, were retrospectively analyzed. All the patients underwent abdominal spectral CT imaging, and conventional kVp images and spectral images were obtained. The CT values of stones and bile were meas- ured from 40 keV to 140keV with 10 increment and their spectral curves slopes were calculated. All parameters were com- pared with t test. Results The CT values of stones increased while the bile decreased gradually from 40 KeV to 140 KeV. There were statistically difference in monochromatic images from 40 keV to 60 keV and from 80 keV to 140 keV be- tween stones and bile （ P 〈 0.01 for all）. There was no statistically difference at 70 KeV （ t = 1.57, P = 0. 129）. There were statistically difference in the slope of spectral curve between stones and bile （ -0. 838 ±0. 187,0. 300 ± 0. 102 ）. Conclusion Single-energy imaging and spectral curve is conducive to display isodense cholesterol stone that cant be dis- played by conventional CT.