Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
Department of Computer Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
Comput Med Imaging Graph. 2021 Apr;89:101830. doi: 10.1016/j.compmedimag.2020.101830. Epub 2021 Jan 28.
High field strength 3T and 7T Time-Of-Flight Magnetic Resonance Angiography (TOF- MRA) achieves better visualization of intracranial vessels, so it attracts much attention. However, quantitative comparison between 3T and 7T MRA is lacking in the aspects of image quality and the practical application of cerebrovascular diseases.
In this paper, a quantitative framework of 3T and 7T TOF-MRA comparison is proposed, which contains two steps including the automated cerebrovascular segmentation and statistical analysis. Firstly, the whole vascular structures on both 3T and 7T TOF-MRA images are segmented automatically, especially those small blood vessels in 7T MRA. The skeleton extraction-based automatic seed point detection is implemented to ensure the segmented vascular structure complete and precise. Secondly, the statistical analysis of the differences between 3T and 7T MRA is carried out in the aspects of image quality and the characteristics of some important vessels. The objects of statistical analysis are achieved and analyzed automatically without needing the time- consuming human beings' participation, therefore, it is efficient and objective.
The comparison experiments on seven pairs of 3T and 7T TOF MRA images validated that about image quality, the contrast-to-noise ratio of 7T MRA was about 4.53 ± 0.95 times as much as that of 3T MRA. About the cerebrovascular information, small vessels were more abundant in 7T MRA compared with 3T MRA (branches number: 462.0 ± 58.5 vs 393.1 ± 63.3).
The proposed framework can segment the whole cerebrovascular structure automatically and compare TOF-MRA with different field strengths objectively and quantitatively. It is helpful for clinical cerebrovascular disease, especially cerebral small vessel diseases.
高磁场强度 3T 和 7T 时间飞跃磁共振血管造影（TOF-MRA）可实现更好的颅内血管可视化，因此备受关注。然而，在图像质量和脑血管疾病的实际应用方面，3T 和 7T MRA 之间缺乏定量比较。
本文提出了一种 3T 和 7T TOF-MRA 比较的定量框架，包含两步，包括自动脑血管分割和统计分析。首先，自动分割 3T 和 7T TOF-MRA 图像上的整个血管结构，特别是 7T MRA 中的小血管。基于骨架提取的自动种子点检测可确保分割的血管结构完整和精确。其次，在图像质量和一些重要血管特征方面进行 3T 和 7T MRA 的差异统计分析。统计分析的对象是通过无需耗时的人工参与自动实现和分析的，因此，该方法高效且客观。
对 7 对 3T 和 7T TOF MRA 图像的比较实验表明，在图像质量方面，7T MRA 的对比噪声比约为 3T MRA 的 4.53 ± 0.95 倍。在脑血管信息方面，7T MRA 中的小血管比 3T MRA 更丰富（分支数：462.0 ± 58.5 比 393.1 ± 63.3）。
所提出的框架可以自动分割整个脑血管结构，并客观、定量地比较不同场强的 TOF-MRA。它有助于临床脑血管疾病，特别是脑小血管疾病。
