Department of Radiological Sciences, Policlinico G. Martino, University of Messina, Messina, Italy.
Clin Radiol. 2013 Feb;68(2):e87-94. doi: 10.1016/j.crad.2012.11.001. Epub 2012 Dec 6.
To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic-excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan.
Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic-excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated.
The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%.
Single-phase DECT urography with synchronous nephrographic-excretory phase enhancement represents an accurate "all-in-one'' approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol.
评估单次双能 CT 尿路造影（DECT）同步肾分泌期增强方案的价值，并计算省略平扫时潜在的剂量减少。
84 例血尿患者行 CT 尿路造影，采用包括单能平扫和双能对比增强同步肾分泌期扫描的方案。重建基于 DECT 的图像[虚拟平扫（VUE）、加权平均和彩色碘叠加]。使用 4 分制独立评估上尿路对比剂充盈程度和虚拟平扫图像质量。确定基于 DECT 的图像检测尿路上皮肿瘤的诊断准确性。通过将单能平扫的有效剂量乘以 2 来获得理论双期单能方案的剂量。计算省略平扫时的辐射剂量节省。
86.9%的病例（k = 0.72）充盈程度评分良好或优秀；83.3%的病例（k = 0.82）VUE 图像质量为优或良。检测尿路上皮肿瘤的敏感性、特异性、阳性预测值和阴性预测值分别为 85.7%、98.6%、92.3%和 97.1%。省略平扫导致平均剂量减少 42.7 ± 5%。
与标准双期方案相比，单次双能 CT 尿路造影同步肾分泌期增强可实现准确的“一站式”检查，辐射剂量节省高达 45%。
