Department of Radiology and Department of Medicine, Division of Cardiology, University of British Columbia, St. Paul's Hospital, 1081 Burrard St., Vancouver, BC V6N 2N7, Canada.
AJR Am J Roentgenol. 2010 Sep;195(3):649-54. doi: 10.2214/AJR.10.4285.
The purpose of our study was to determine the effect of Adaptive Statistical Iterative Reconstruction (ASIR) on cardiac CT angiography (CTA) signal, noise, and image quality.
We evaluated 62 consecutive patients at three sites who underwent clinically indicated cardiac CTA using an ASIR-capable 64-MDCT scanner and a low-dose cardiac CTA technique. Studies were reconstructed using filtered back projection (FBP), ASIR-FBP composites using 20-80% ASIR, and 100% ASIR. The signal and noise were measured in the aortic root and each of the four coronary arteries. Two blinded readers graded image quality on a 5-point Likert scale and determined the proportion of interpretable segments. All segments were included for analysis regardless of size.
In comparison with FBP (0% ASIR), the use of 20%, 40%, 60%, 80%, and 100% ASIR resulted in reduced image noise between groups (-7%, -17%, -26%, -35%, and -43%, respectively; p < 0.001) without difference in signal (p = 0.60). There were significant differences between groups (0%, 20%, 40%, 60%, 80%, and 100% ASIR) in the Likert scores (1.5, 2.1, 3.7, 3.8, 2.0, and 1.1, respectively; p < 0.001) and proportion of interpretable segments (88.7%, 89.3%, 90.5%, 90.4%, 88.0%, and 87.3%, respectively; p < 0.001). Reconstruction using 40% and 60% ASIR had the highest Likert scores and largest proportion of interpretable segments. In comparison with FBP, each was associated with higher Likert scores and increased interpretable segments (p < 0.001 for all).
ASIR resulted in noise reduction and significantly impacted image quality. When using a low tube current technique, cardiac CTA reconstruction using 40% or 60% ASIR significantly improved image quality and the proportion of interpretable segments compared with FBP reconstruction.
我们的研究目的是确定自适应统计迭代重建（ASIR）对心脏 CT 血管造影（CTA）信号、噪声和图像质量的影响。
我们在三个地点评估了 62 名连续的患者，他们使用配备 ASIR 功能的 64-MDCT 扫描仪和低剂量心脏 CTA 技术进行临床指征的心脏 CTA。研究使用滤波反投影（FBP）、ASIR-FBP 复合材料（ASIR 为 20-80%）和 100%ASIR 进行重建。在主动脉根部和四个冠状动脉中的每一个部位测量信号和噪声。两位盲法读者使用 5 分李克特量表对图像质量进行评分，并确定可解释节段的比例。所有节段均包括在分析中，无论大小如何。
与 FBP（0%ASIR）相比，使用 20%、40%、60%、80%和 100%ASIR 分别导致组间图像噪声降低（分别为-7%、-17%、-26%、-35%和-43%；p<0.001），而信号无差异（p=0.60）。组间（0%、20%、40%、60%、80%和 100%ASIR）的李克特评分（分别为 1.5、2.1、3.7、3.8、2.0 和 1.1；p<0.001）和可解释节段的比例（分别为 88.7%、89.3%、90.5%、90.4%、88.0%和 87.3%；p<0.001）存在显著差异。使用 40%和 60%ASIR 进行重建的李克特评分最高，可解释节段比例最大。与 FBP 相比，两者均与更高的李克特评分和更多的可解释节段相关（所有 p<0.001）。
ASIR 可降低噪声，并显著影响图像质量。当使用低管电流技术时，与 FBP 重建相比，心脏 CTA 重建使用 40%或 60%ASIR 可显著改善图像质量和可解释节段的比例。
