Scheffel Hans, Stolzmann Paul, Frauenfelder Thomas, Schertler Thomas, Desbiolles Lotus, Leschka Sebastian, Marincek Borut, Alkadhi Hatem
Department of Medical Radiology, Institute of Diagnostic Radiology, University of Zurich, Zurich, Switzerland.
Invest Radiol. 2007 Dec;42(12):823-9. doi: 10.1097/RLI.0b013e3181379bac.
To assess the value of dual-energy contrast-enhanced computed tomography (CT) imaging for the detection of urinary stone disease using dual-source CT.
Forty consecutive patients (mean age 46.6 +/- 16.2 years, range 27-85 years) suspected of having urinary stone disease underwent dual-source CT of the urinary tract. A 3-phasic CT scan protocol consisting of a standard unenhanced scan, a nephrographic, and an excretory phase of contrast enhancement was performed. The nephrographic phase scan was acquired in the dual-energy mode (80 kV/400 mA and 140 kV/95 mA) allowing reconstruction of virtual unenhanced images. Two blinded readers independently compared standard and virtual unenhanced CT for the number, size, and location of urinary stones. Measurements of anteroposterior abdominal diameters were performed to determine abdominal obesity.
Standard unenhanced CT revealed 35 uroliths in 18 of the 40 patients (18 of 40; 45%), virtual unenhanced CT demonstrated 26 uroliths in 15 of the 40 patients (15 of 40; 38%) ([kappa] value 0.89). Three false-negative and no false-positive ratings occurred using virtual unenhanced CT, and false-negative ratings solely occurred in obese patients. Sensitivity, specificity, positive predictive, and negative predictive values for virtual unenhanced CT for the diagnosis of urinary stone disease were 83%, 100%, 100%, and 88%, respectively.
Virtual unenhanced CT images reconstructed from contrast-enhanced dual-energy CT allow detection of urinary stones with good sensitivity and excellent specificity, but sensitivity is decreased in abdominal obese patients.
使用双源CT评估双能量对比增强计算机断层扫描（CT）成像在检测尿路结石疾病中的价值。
40例连续怀疑患有尿路结石疾病的患者（平均年龄46.6±16.2岁，范围27 - 85岁）接受了尿路双源CT检查。执行了一个三相CT扫描方案，包括标准平扫、肾实质期和排泄期对比增强扫描。肾实质期扫描以双能量模式（80 kV/400 mA和140 kV/95 mA）采集，以允许重建虚拟平扫图像。两位盲法阅片者独立比较标准平扫CT和虚拟平扫CT上尿路结石的数量、大小和位置。测量腹部前后径以确定腹部肥胖情况。
标准平扫CT在40例患者中的18例（40例中的18例；45%）发现了35枚尿路结石，虚拟平扫CT在40例患者中的15例（40例中的15例；38%）发现了26枚尿路结石（κ值0.89）。使用虚拟平扫CT出现3例假阴性且无假阳性结果，假阴性结果仅出现在肥胖患者中。虚拟平扫CT诊断尿路结石疾病的敏感性、特异性、阳性预测值和阴性预测值分别为83%、100%、100%和88%。
从对比增强双能量CT重建的虚拟平扫CT图像能够以良好的敏感性和优异的特异性检测尿路结石，但在腹部肥胖患者中敏感性会降低。
