Department of Radiology, Sapporo Azabu Neurosurgical Hospital, N22, E1, Higashi-Ku, Sapporo 065-0022, Japan.
Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan.
Acad Radiol. 2021 Jan;28(1):e14-e19. doi: 10.1016/j.acra.2020.01.010. Epub 2020 Feb 7.
To evaluate the depictability of intracranial small arteries using high-resolution CTA with model-based iterative reconstruction (MBIR).
We retrospectively analyzed 21 patients who underwent brain 3D-CTA. Axial and volume-rendered (VR) images were reconstructed from the 3D-CTA raw data using adaptive statistical image reconstruction (ASIR) and MBIR. As a quantitative assessment, intra-arterial CT values of the ICA and contrast-to-noise ratio were measured to evaluate vessel enhancement. Additionally, CT values and standard deviations (SDs) of CT values and signal to noise ratio in white matter parenchyma were measured to evaluate background noise. As a qualitative assessment, the degree of vessel depictability in the anterior choroidal artery (AchoA) and the perforating branches of thalamoperforating arteries (TPA) on VR images using two different reconstruction algorithms was visually evaluated using a 3-point grading system.
The CT value of the ICA [605.27± 89.76 Hounsfield units (HU)] was significantly increased and the SD value (i.e., image noise) of the white matter parenchyma [6.79 ± 0.81(HU)] was decreased on MBIR compared with ASIR [546.76 ± 85.27 (HU)] and [8.04 ± 1.08 HU)] (p <.05 for all). Contrast-to-noise ratio of ICA [84.48 ± 20.17] and signal to noise ratio of white matter [6.18 ± 0.75] with MBIR were significantly higher than ASIR [65.98 ± 13.08] and [5.28 ± 0.78] (p < 0.05 for all). In addition, depictions of the AchoA and TPA on VR images were significantly improved using MBIR compared with ASIR (p < 0.05).
MBIR allows depiction of small intracranial arteries such as AchoA and TPA with better visibility than ASIR without increasing the dose of radiation and the amount of contrast agent.
利用基于模型的迭代重建（MBIR）技术评估高分辨率 CTA 对颅内小动脉的可描绘性。
回顾性分析 21 例行脑 3D-CTA 的患者。使用自适应统计图像重建（ASIR）和 MBIR 从 3D-CTA 原始数据重建轴向和容积再现（VR）图像。作为定量评估，测量颈内动脉（ICA）的动脉内 CT 值和对比噪声比以评估血管增强。此外，还测量了脑白质实质的 CT 值和标准偏差（SD）以及信噪比，以评估背景噪声。作为定性评估，使用 3 分制对两种不同重建算法的 VR 图像上前脉络膜动脉（AchoA）和穿通支动脉（TPA）的血管可描绘程度进行视觉评估。
MBIR 组 ICA 的 CT 值[605.27±89.76 亨氏单位（HU）]显著升高，脑白质实质的 SD 值（即图像噪声）[6.79 ±0.81 HU]降低，与 ASIR 组[546.76 ±85.27 HU]和[8.04 ±1.08 HU]相比（所有 p<0.05）。MBIR 组 ICA 的对比噪声比[84.48 ±20.17]和脑白质的信噪比[6.18 ±0.75]明显高于 ASIR 组[65.98 ±13.08]和[5.28 ±0.78]（所有 p<0.05）。此外，与 ASIR 相比，MBIR 可显著改善 VR 图像上 AchoA 和 TPA 的描绘效果（p<0.05）。
与 ASIR 相比，MBIR 可以在不增加辐射剂量和造影剂用量的情况下，更好地显示颅内小动脉，如 AchoA 和 TPA，提高可描绘性。
