Grob Dagmar, Smit Ewoud, Oostveen Luuk J, Snoeren Miranda M, Prokop Mathias, Schaefer-Prokop Cornelia M, Sechopoulos Ioannis, Brink Monique
Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Post 766, Nijmegen, The Netherlands.
Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, The Netherlands.
AJR Am J Roentgenol. 2019 Jun;212(6):1253-1259. doi: 10.2214/AJR.18.20786. Epub 2019 Mar 12.
The objective of this study was to compare the image quality of iodine maps derived from subtraction CT and from dual-energy CT (DECT) in patients with suspected pulmonary embolism (PE). In this prospective study conducted between July 2016 and April 2017, consecutive patients with suspected PE underwent unenhanced CT at 100 kV and dual-energy pulmonary CT angiography at 100 and 140 kV on a dual-source scanner. The scanner was set to generate subtraction and DECT iodine maps at similar radiation doses. In 55 patients (30 women, 25 men; mean age ± SD, 63.4 ± 11.9 years old), various subjective image quality criteria including diagnostic acceptability were rated on a 5-point scale by four radiologists and a radiology resident. In 29 patients (17 women, 12 men; mean age, 62.4 ± 11.7 years old) with confirmed perfusion defects, the signal-difference-to-noise ratio (SDNR) between perfusion defects and adjacent normally perfused parenchyma was measured in corresponding ROIs on subtraction and DECT iodine maps. McNemar and Wilcoxon signed-rank tests were used for statistical comparisons. Diagnostic acceptability was rated excellent or good in a mean of 67% (range, 31-80%) of subtraction CT studies and 36% (5-69%) of DECT studies ( < 0.05 for four of the five radiologists), mainly because of fewer artifacts on subtraction CT. Mean SDNR was marginally higher for subtraction CT than for DECT (18.6 vs 17.1, = 0.06) and was significantly higher in the upper lobes (21.8 vs 17.9, < 0.05). Radiologist-judged image quality of pulmonary iodine maps was higher for subtraction CT than for DECT with similar to higher SDNR. Subtraction CT is a software-only solution, so it may be an attractive alternative to DECT for depicting perfusion defects.
本研究的目的是比较在疑似肺栓塞（PE）患者中，采用减影CT和双能CT（DECT）获得的碘图的图像质量。在这项于2016年7月至2017年4月进行的前瞻性研究中，连续的疑似PE患者在双源扫描仪上接受了100 kV的平扫CT以及100 kV和140 kV的双能肺CT血管造影检查。扫描仪设置为在相似的辐射剂量下生成减影碘图和DECT碘图。在55例患者（30例女性，25例男性；平均年龄±标准差，63.4±11.9岁）中，由四位放射科医生和一名放射科住院医师根据包括诊断可接受性在内的各种主观图像质量标准进行5分制评分。在29例（17例女性，12例男性；平均年龄，62.4±11.7岁）确诊有灌注缺损的患者中，在减影碘图和DECT碘图上相应的感兴趣区测量灌注缺损与相邻正常灌注实质之间的信号差与噪声比（SDNR）。采用McNemar检验和Wilcoxon符号秩检验进行统计学比较。减影CT研究中，平均67%（范围，31 - 80%）的诊断可接受性被评为优秀或良好，而DECT研究中这一比例为36%（5 - 69%）（五位放射科医生中有四位的结果<0.05），主要原因是减影CT上的伪影较少。减影CT的平均SDNR略高于DECT（18.6对17.1，P = 0.06），且在上叶显著更高（21.8对17.9，P < 0.05）。放射科医生判断的肺部碘图图像质量，减影CT高于DECT，且SDNR相似或更高。减影CT是一种仅通过软件的解决方案，因此在描绘灌注缺损方面，它可能是DECT的一个有吸引力的替代方案。
