OBJECTIVES To propose and evaluate a four-dimensional (4D) algorithm for joint motion elimination and spatiotemporal noise reduction in low-dose dynamic myocardial computed tomography perfusion (CTP). METHODS Thirty patients with suspected or confirmed coronary artery disease were prospectively included and underwent dynamic contrast-enhanced 320-row CTP. A novel deformable image registration method based on the principal component analysis (PCA) of the ante hoc temporally smoothed voxel-wise time-attenuation curves (ASTRA4D) is presented. Quantitative (standard deviation, signal-to-noise ratio (SNR), temporal variation, volumetric deformation) and qualitative (motion, contrast, contour sharpness [1, poor; 5, excellent]) measures of CTP quality were assessed for the original and motion-compensated sequences (without and with temporal filtering, PCA/ASTRA4D). Following myocardial perfusion deficit detection by two readers, diagnostic accuracy was evaluated using magnetic resonance myocardial perfusion imaging (MR-MPI) as the reference standard in 15 patients. RESULTS Registration using ASTRA4D was successful in all 30 patients and resulted in comparison with the benchmark PCA in significantly (p < 0.001) reduced noise over time (- 83%, 178.5 vs 29.9) and spatially (- 34%, 21.4 vs 14.1) as well as improved SNR (+ 47%, 3.6 vs 5.3) and subjective image quality (motion, contrast, contour sharpness [+ 1.0, + 1.0, + 0.5]). ASTRA4D had significantly improved per-segment sensitivity of 91% (58/64) and similar specificity of 96% (429/446) compared with PCA (52%, 33/64; 98%, 435/446; p = 0.011) in the visual detection of perfusion deficits. CONCLUSIONS The ASTRA4D registration algorithm improved the spatiotemporal noise profile and CTP sequence image quality, resulting in significantly improved sensitivity of 4D CTP in the detection of myocardial ischemia. KEY POINTS • ASTRA4D combines local temporal regression and deformable image registration. • Quantitative and qualitative measures of CTP quality are improved compared to PCA. • Improved spatiotemporal differentiation of ischemic regions leads to an excellent perfusion deficit concordance of ASTRA4D with MRI.

中文翻译：

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低剂量4D心肌计算机体层摄影术灌注（CTP）中的降噪和运动消除：ASTRA4D算法的初步临床评估。

目的提出并评估用于低剂量动态心肌计算机断层扫描灌注（CTP）的关节运动消除和时空降噪的四维（4D）算法。方法前瞻性纳入30例怀疑或确诊为冠心病的患者，并进行动态对比增强的320行CTP。提出了一种基于前临时时间平滑体素时间衰减曲线（ASTRA4D）主成分分析（PCA）的可变形图像配准方法。评估了CTP质量的定量（标准偏差，信噪比（SNR），时间变化，体积变形）和定性（运动，对比度，轮廓清晰度[1，差； 5，极好]）的量度。运动补偿序列（不带时间滤波，PCA / ASTRA4D）。在两名阅读器检测到心肌灌注不足后，使用磁共振心肌灌注成像（MR-MPI）作为参考标准评估了15例患者的诊断准确性。结果在所有30例患者中，使用ASTRA4D的注册均成功，并且与基准PCA相比，随着时间的推移（-83％，178.5 vs 29.9）和空间（-34％，21.4 vs 14.1）显着降低了噪声（-83％，178.5 vs 29.9）。以及改善的SNR（+ 47％，3.6与5.3）和主观图像质量（运动，对比度，轮廓清晰度[+ 1.0，+ 1.0，+ 0.5]）。与PCA（52％，33/64; 98％，435/446; p = 0.011）相比，ASTRA4D的每段敏感性显着提高了91％（58/64），相似特异性达到96％（429/446）。视觉检测灌注不足。结论ASTRA4D配准算法改善了时空噪声特征和CTP序列图像质量，从而显着提高了4D CTP在检测心肌缺血中的敏感性。要点•ASTRA4D结合了局部时间回归和可变形图像配准。•与PCA相比，CTP质量的定量和定性指标得到了改善。•缺血区域时空差异的改善导致ASTRA4D与MRI的良好的灌注不足一致性。•与PCA相比，CTP质量的定量和定性指标得到了改善。•缺血区域时空差异的改善导致ASTRA4D与MRI的良好的灌注不足一致性。•与PCA相比，CTP质量的定量和定性指标得到了改善。•缺血区域时空差异的改善导致ASTRA4D与MRI的良好的灌注不足一致性。