From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.).
Radiology. 2019 Jul;292(1):197-205. doi: 10.1148/radiol.2019182666. Epub 2019 May 14.
Background Dual-energy CT iodine maps are used to detect pulmonary embolism (PE) with CT angiography but require dedicated hardware. Subtraction CT, a software-only solution, results in iodine maps with high contrast-to-noise ratios. Purpose To compare the use of subtraction CT versus dual-energy CT iodine maps to CT angiography for PE detection. Materials and Methods In this prospective study ( , NCT02890706), 274 participants suspected of having PE underwent precontrast CT followed by contrast material-enhanced dual-energy CT angiography between July 2016 and April 2017. Iodine maps from dual-energy CT were derived. Subtraction maps (contrast-enhanced CT minus precontrast CT) were calculated after motion correction. Truth was established by expert consensus. A total of 75 randomly selected participants with and without PE (1:1 ratio) were evaluated by three radiologists and six radiology residents (blinded to final diagnosis) for the presence of PE using three types of CT: CT angiography alone, dual-energy CT, and subtraction CT. The partial area under the receiver operating characteristic curve (AUC) for the clinically relevant specificity region (maximum partial AUC, 0.11) was compared by using multireader multicase variance. A value less than or equal to .025 was considered indicative of a significant difference due to multiple comparisons. Results There were 35 men and 40 women in the reader study (mean age, 63 years ± 12 [standard deviation]). The pooled sensitivities were not different ( ≥ .31 among techniques) (95% confidence intervals [CIs]: 67%, 89% for CT angiography; 72%, 91% for dual-energy CT; 70%, 91% for subtraction CT). However, pooled specificity was higher for subtraction CT (95% CI: 100%, 100%) than for CT angiography (95% CI: 89%, 97%) or dual-energy CT (95% CI: 89%, 98%) ( < .001). Partial AUCs for the average observer improved equally when adding iodine maps (subtraction CT [0.093] vs CT angiography [0.088], = .03; dual-energy CT [0.094] vs CT angiography, = .01; dual-energy CT vs subtraction CT, = .68). Average reading times were equivalent (range, 97-101 seconds; ≥ .41) among techniques. Conclusion Subtraction CT iodine maps had greater specificity than CT angiography alone in pulmonary embolism detection. Subtraction CT had comparable diagnostic performance to that of dual-energy CT, without the need for dedicated hardware. © RSNA, 2019
背景 双能 CT 碘图用于 CT 血管造影术检测肺栓塞 (PE)，但需要专用硬件。仅使用软件的减影 CT 可生成具有高对比度噪声比的碘图。目的 比较减影 CT 与双能 CT 碘图在 PE 检测方面与 CT 血管造影术的应用。材料与方法 在这项前瞻性研究（ ，NCT02890706）中，274 名疑似患有 PE 的参与者于 2016 年 7 月至 2017 年 4 月期间先行平扫 CT，然后行对比增强双能 CT 血管造影术。从双能 CT 中获得碘图。在运动校正后计算减影图（增强 CT 减去平扫 CT）。专家共识确定了真相。共有 75 名随机选择的有或无 PE 的参与者（1:1 比例），由 3 名放射科医生和 6 名放射科住院医师（对最终诊断设盲）使用 3 种 CT 方法进行评估：单独 CT 血管造影术、双能 CT 和减影 CT。使用多读者多病例方差比较最大部分 AUC（0.11）范围内的部分 AUC（AUC）的临床相关特异性区域（最大部分 AUC，0.11）。由于多次比较， 值小于或等于.025 被认为具有统计学意义。结果 在读者研究中，有 35 名男性和 40 名女性（平均年龄，63 岁±12[标准差]）。汇总的敏感度没有差异（≥.31 的技术）（95%置信区间[CI]：CT 血管造影术为 67%，89%；双能 CT 为 72%，91%；减影 CT 为 70%，91%）。然而，减影 CT 的汇总特异性（95%CI：100%，100%）高于 CT 血管造影术（95%CI：89%，97%）或双能 CT（95%CI：89%，98%）（<.001）。当添加碘图时，平均观察者的 AUC 部分（减影 CT [0.093]与 CT 血管造影术 [0.088]， =.03；双能 CT [0.094]与 CT 血管造影术， =.01；双能 CT 与减影 CT， =.68）有所提高。技术间的平均阅读时间相等（范围，97-101 秒； ≥.41）。结论 在肺栓塞检测中，减影 CT 碘图的特异性优于单独 CT 血管造影术。减影 CT 与双能 CT 具有相当的诊断性能，而无需专用硬件。©RSNA，2019
