Computation of contrast-enhanced perfusion using only two CT scan phases: a proof-of-concept study on abdominal organs

Cressoni M, Cozzi A, Schiaffino S, Cadringher P, Vitali P, Basso G, Ippolito D, Sardanelli F. Computation of contrast-enhanced perfusion using only two CT scan phases: a proof-of-concept study on abdominal organs. Eur Radiol Exp. 2022 Aug 29;6(1):37. doi: 10.1186/s41747-022-00292-y. PMID: 36031643; PMCID: PMC9420683. Abstract Background: Computed tomography perfusion imaging (CTPI) by repeated scanning has clinical relevance but implies relatively high radiation exposure. We present a method to measure perfusion from two CT scan phases only, considering tissue enhancement, feeding vessel (aortic) peak enhancement, and bolus shape. Methods: CTPI scans (each with 40 frames acquired every 1.5 s) of 11 patients with advanced hepatocellular carcinoma (HCC) enrolled between 2012 and 2016 were retrospectively analysed (aged 69 ± 9 years, 8/11 males). Perfusion was defined as the maximal slope of the time-enhancement curve divided by the peak enhancement of the feeding vessel (aorta). Perfusion was computed two times, first using the maximum slope derived from all data points and then using the peak tissue enhancement and the bolus shape obtained from the aortic curve. Results: Perfusion values from the two methods were linearly related (r2 = 0.92, p < 0.001; Bland-Altman analysis bias -0.12). The mathematical model showed that the perfusion ratio of two ROIs with the same feeding vessel (aorta) corresponds to their peak enhancement ratio (r2 = 0.55, p < 0.001; Bland-Altman analysis bias -0.68). The relationship between perfusion and tissue enhancement is predicted to be linear in the clinical range of interest, being only function of perfusion, peak feeding vessel enhancement, and bolus shape. Conclusions: This proof-of-concept study showed that perfusion values of HCC, kidney, and pancreas could be computed using enhancement measured only with two CT scan phases, if aortic peak enhancement and bolus shape are known.Cressoni M, Cozzi A, Schiaffino S, Cadringher P, Vitali P, Basso G, Ippolito D, Sardanelli F. 仅利用双期CT扫描计算增强灌注：针对腹部脏器的概念验证研究. European Radiology Experimental. 2022年8月29日;6(1):37. doi: 10.1186/s41747-022-00292-y. PMID: 36031643; PMCID: PMC9420683. 摘要 背景：采用重复扫描方式的计算机断层扫描灌注成像（Computed tomography perfusion imaging, CTPI）虽具备临床应用价值，但辐射暴露量相对较高。本研究提出一种仅依托双期CT扫描测量灌注的方法，该方法综合纳入组织增强程度、供血血管（主动脉）峰值增强水平及造影剂团注形态三类参数。方法：对2012年至2016年间入组的11例晚期肝细胞癌（hepatocellular carcinoma, HCC）患者的CTPI扫描数据进行回顾性分析，患者年龄为69±9岁，其中男性8例。所有扫描均以每1.5秒1帧的采样频率采集40帧图像。灌注被定义为时间-增强曲线的最大斜率除以供血血管（主动脉）的峰值增强程度。分别通过两种方式计算灌注：第一种使用全部数据点得到的最大斜率，第二种则利用从主动脉曲线获取的组织峰值增强与造影剂团注形态。结果：两种方法所得灌注值呈显著线性相关（r²=0.92, P<0.001; Bland-Altman分析偏倚为-0.12）。数学模型分析显示，供血血管（主动脉）相同的两个感兴趣区（Region of Interest, ROI）的灌注比值与峰值增强比值具有一致性（r²=0.55, P<0.001; Bland-Altman分析偏倚为-0.68）。在临床关注的范围内，灌注与组织增强程度的关系呈线性，且仅由灌注、供血血管峰值增强水平及造影剂团注形态决定。结论：本概念验证研究证实，若已知主动脉峰值增强水平与造影剂团注形态，仅通过双期CT扫描测得的增强值即可计算肝细胞癌、肾脏及胰腺的灌注值。