Background

Myocardial perfusion measurement with a low-dose first-pass analysis (FPA) dynamic computed tomography (CT) perfusion technique depends upon acquisition of two whole-heart volume scans at the base and peak of the aortic enhancement. Hence, the objective of this study was to validate an optimal timing protocol for volume scan acquisition at the base and peak of the aortic enhancement.

Methods

Contrast-enhanced CT of 28 Yorkshire swine (weight, 55 ± 24 kg, mean ± standard deviation) was performed under rest and stress conditions over 20–30 s to capture the aortic enhancement curves. From these curves, an optimal timing protocol was simulated, where one volume scan was acquired at the base of the aortic enhancement while a second volume scan was acquired at the peak of the aortic enhancement. Low-dose FPA perfusion measurements (P_FPA) were then derived and quantitatively compared to the previously validated retrospective FPA perfusion measurements as a reference standard (P_REF). The 32-cm diameter volume CT dose index, \( {\mathrm{CTDI}}_{\mathrm{vol}}^{32} \) and size-specific dose estimate (SSDE) of the low-dose FPA perfusion protocol were also determined.

Results

P_FPA were related to the reference standard by P_FPA = 0.95 · P_REF + 0.07 (r = 0.94, root-mean-square error = 0.27 mL/min/g, root-mean-square deviation = 0.04 mL/min/g). The \( {\mathrm{CTDI}}_{\mathrm{vol}}^{32} \) and SSDE of the low-dose FPA perfusion protocol were 9.2 mGy and 14.6 mGy, respectively.

Conclusions

An optimal timing protocol for volume scan acquisition at the base and peak of the aortic enhancement was retrospectively validated and has the potential to be used to implement an accurate, low-dose, FPA perfusion technique.

中文翻译：

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低剂量首过分析动态CT心肌灌注测量的时序优化：在猪模型中的验证。

背景

使用低剂量首过分析 (FPA) 动态计算机断层扫描 (CT) 灌注技术进行心肌灌注测量取决于在主动脉增强的底部和峰值处采集两次全心容积扫描。因此，本研究的目的是验证在主动脉增强的底部和峰值处进行体积扫描采集的最佳时间协议。

方法

对 28 只约克郡猪（体重，55 ± 24 kg，平均值 ± 标准差）进行了 20-30 秒的休息和压力条件下的对比增强 CT，以捕捉主动脉增强曲线。从这些曲线中，模拟了一个最佳时间协议，其中在主动脉增强的底部获得了一次体积扫描，而在主动脉增强的峰值处获得了第二次体积扫描。然后得出低剂量 FPA 灌注测量值 ( P _FPA ) 并与之前验证的回顾性 FPA 灌注测量值作为参考标准 ( P _REF ) 进行定量比较。32 厘米直径体积 CT 剂量指数，\( {\mathrm{CTDI}}_{\mathrm{vol}}^{32} \)还确定了低剂量 FPA 灌注方案的尺寸特异性剂量估计 (SSDE)。

结果

P _FPA与参考标准的相关性为P _FPA  = 0.95 · P _REF  + 0.07 ( r  = 0.94，均方根误差 = 0.27 mL/min/g，均方根偏差 = 0.04 mL/min/g ）。低剂量 FPA 灌注方案的\( {\mathrm{CTDI}}_{\mathrm{vol}}^{32} \)和 SSDE 分别为 9.2 mGy 和 14.6 mGy。

结论

回顾性验证了在主动脉增强底部和峰值处进行体积扫描采集的最佳时间协议，并有可能用于实施准确的低剂量 FPA 灌注技术。