Department of Radiology and Division of Epidemiology and Biostatistics, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy.
Radiology. 2012 Nov;265(2):448-56. doi: 10.1148/radiol.12111232. Epub 2012 Sep 20.
To assess the variability of breath-hold perfusion computed tomography (CT) parameters and to investigate whether these measurements are affected by a commercial software upgrade in patients with hepatocellular carcinoma (HCC).
Written informed consent was obtained from all participants in this institutional ethics committee-approved study. Perfusion CT examinations in HCC patients were prospectively analyzed by three readers. Two readers repeated their analysis after an interval of at least 4 weeks. Inter- and intraobserver agreement, as well as intersoftware agreement, were assessed with intraclass correlation coefficients (ICCs) and Bland-Altman limits of agreement (LoA), with adjustment for correlation between repeated measures.
Ninety-three breath-hold perfusion CT examinations were included from 23 HCC patients. The ICC between readers was very high (>0.91) for blood flow (BF), high (>0.84) for blood volume (BV), and lower (>0.30 and >0.39) for mean transit time (MTT) and permeability surface area product (PS), respectively, while ICC between readings was high (>0.80) for BF and BV, good (>0.75) for PS, and lower (>0.38) for MTT, irrespective of software version. By using the current software, the clinically relevant percentage of LoA between readers for BF were -33%; for BV, -39%; for MTT, 55%; and for PS, -93%. Between readings by the most expert reader, the clinically relevant LoA were -35% for BF,-43% for BV, 33% for MTT, and -79% for PS. BF, BV, and PS values were significantly higher and MTT values were significantly lower (P<.01) with the current software version relative to the previous version.
With the current CT perfusion software, only decreases between scans of HCC lesions of more than 35% for BF and 43% for BV, or an increase of more than 55% for MTT, could be considered beyond the analysis variability. The perfusion parameters obtained with the current and previous software versions were not exchangeable. The results of this study are specific for breath-hold perfusion CT of HCC and may not apply to different acquisition protocols and tumors.
评估屏气灌注 CT（CT）参数的可变性，并研究这些测量值是否受商业软件升级的影响，以用于肝细胞癌（HCC）患者。
本研究经机构伦理委员会批准，所有参与者均签署书面知情同意书。对 HCC 患者的灌注 CT 检查进行前瞻性分析，由 3 位读者进行。两位读者在至少 4 周的间隔后重复他们的分析。使用组内相关系数（ICC）和 Bland-Altman 协议限（LoA）评估组内和组间一致性以及软件间一致性，并对重复测量之间的相关性进行调整。
纳入了 23 例 HCC 患者的 93 次屏气灌注 CT 检查。对于血流（BF），读者之间的 ICC 非常高（>0.91）；对于血容量（BV），ICC 高（>0.84）；对于平均通过时间（MTT）和渗透率表面积乘积（PS），ICC 分别较低（>0.30 和>0.39），而读者之间的 ICC 对于 BF 和 BV 较高（>0.80），对于 PS 良好（>0.75），对于 MTT 较低（>0.38），与软件版本无关。使用当前软件，读者之间 BF 的临床相关 LoA 百分比为-33%；BV 为-39%；MTT 为 55%；PS 为-93%。最有经验的读者两次阅读之间的临床相关 LoA 为 BF-35%，BV-43%，MTT 33%，PS-79%。与前一版本相比，当前软件版本的 BF、BV 和 PS 值显著升高，而 MTT 值显著降低（P<.01）。
使用当前 CT 灌注软件，只有 BF 扫描减少超过 35%，BV 减少超过 43%，或 MTT 增加超过 55%，才能认为超出了分析的可变性。当前和以前软件版本获得的灌注参数不能互换。本研究结果特定于 HCC 的屏气灌注 CT，可能不适用于不同的采集方案和肿瘤。
