Noda Yoshifumi, Kawai Nobuyuki, Ishihara Takuma, Tsuboi Yoshiki, Kaga Tetsuro, Miyoshi Toshiharu, Hyodo Fuminori, Matsuo Masayuki
Department of Radiology, Gifu University, Gifu, Japan.
Innovative and Clinical Research Promotion Center, Gifu University Hospital, Gifu, Japan.
Br J Radiol. 2021 Jun 1;94(1122):20210315. doi: 10.1259/bjr.20210315. Epub 2021 May 6.
To determine the optimal scan delay corresponding to individual hemodynamic status for pancreatic parenchymal phase in dynamic contrast-enhanced CT of the abdomen.
One hundred and fourteen patients were included in this retrospective study (69 males and 45 females; mean age, 67.9 ± 12.1 years; range, 39-87 years). These patients underwent abdominal dynamic contrast-enhanced CT between November 2019 and May 2020. We calculated and recorded the time from contrast material injection to the bolus-tracking trigger of 100 Hounsfield unit (HU) at the abdominal aorta (s) (Time) and scan delay from the bolus-tracking trigger to the initiation of pancreatic parenchymal phase scanning (s) (Time). The scan delay ratio (SDR) was defined by dividing the Time by Time. Non-linear regression analysis was conducted to assess the association between CT number of the pancreas and SDR and to reveal the optimal SDR, which was ≥120 HU in pancreatic parenchyma.
The non-linear regression analysis showed a significant association between CT number of the pancreas and the SDR ( < 0.001). The mean Time and Time were 16.1 s and 16.8 s, respectively. The SDR to peak enhancement of the pancreas (123.5 HU) was 1.00. An SDR between 0.89 and 1.18 shows an appropriate enhancement of the pancreas (≥120 HU).
The CT number of the pancreas peaked at an SDR of 1.00, which means Time should be approximately the same as Time to obtain appropriate pancreatic parenchymal phase images in dynamic contrast-enhanced CT with bolus-tracking method.
The hemodynamic state is different in each patient; therefore, scan delay from the bolus-tracking trigger should also vary based on the time from contrast material injection to the bolus-tracking trigger. This is necessary to obtain appropriate late hepatic arterial or pancreatic parenchymal phase images in dynamic contrast-enhanced CT of the abdomen.
确定腹部动态对比增强CT胰腺实质期与个体血流动力学状态相对应的最佳扫描延迟时间。
本回顾性研究纳入了114例患者（男性69例，女性45例；平均年龄67.9±12.1岁；范围39 - 87岁）。这些患者在2019年11月至2020年5月期间接受了腹部动态对比增强CT检查。我们计算并记录了从注射对比剂到腹主动脉处100亨氏单位（HU）的团注追踪触发时间（秒）（时间1）以及从团注追踪触发到开始胰腺实质期扫描的扫描延迟时间（秒）（时间2）。扫描延迟率（SDR）定义为时间2除以时间1。进行非线性回归分析以评估胰腺CT值与SDR之间的关联，并揭示最佳SDR，胰腺实质期SDR≥120 HU。
非线性回归分析显示胰腺CT值与SDR之间存在显著关联（<0.001）。平均时间1和时间2分别为16.1秒和16.8秒。胰腺达到峰值强化（123.5 HU）时的SDR为1.00。SDR在0.89至1.18之间表明胰腺强化适当（≥120 HU）。
胰腺CT值在SDR为1.00时达到峰值，这意味着在采用团注追踪法的腹部动态对比增强CT中，要获得适当的胰腺实质期图像，时间2应大致与时间1相同。
每位患者的血流动力学状态不同；因此，从团注追踪触发开始的扫描延迟也应根据从注射对比剂到团注追踪触发的时间而变化。这对于在腹部动态对比增强CT中获得适当的肝动脉晚期或胰腺实质期图像是必要的。
