Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
Magn Reson Med. 2018 Jan;79(1):554-560. doi: 10.1002/mrm.26674. Epub 2017 Mar 16.
Assessment of blood flow in the left ventricle using four-dimensional flow MRI requires accurate left ventricle segmentation that is often hampered by the low contrast between blood and the myocardium. The purpose of this work is to improve left-ventricular segmentation in four-dimensional flow MRI for reliable blood flow analysis.
The left ventricle segmentations are first obtained using morphological cine-MRI with better in-plane resolution and contrast, and then aligned to four-dimensional flow MRI data. This alignment is, however, not trivial due to inter-slice misalignment errors caused by patient motion and respiratory drift during breath-hold based cine-MRI acquisition. A robust image registration based framework is proposed to mitigate such errors automatically. Data from 20 subjects, including healthy volunteers and patients, was used to evaluate its geometric accuracy and impact on blood flow analysis.
High spatial correspondence was observed between manually and automatically aligned segmentations, and the improvements in alignment compared to uncorrected segmentations were significant (P < 0.01). Blood flow analysis from manual and automatically corrected segmentations did not differ significantly (P > 0.05).
Our results demonstrate the efficacy of the proposed approach in improving left-ventricular segmentation in four-dimensional flow MRI, and its potential for reliable blood flow analysis. Magn Reson Med 79:554-560, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
使用四维血流磁共振成像评估左心室血流需要准确的左心室分割，而这通常受到血液与心肌之间对比度低的影响。本研究旨在改进四维血流磁共振成像中的左心室分割，以进行可靠的血流分析。
首先使用具有更好的平面内分辨率和对比度的形态学电影磁共振成像获得左心室分割，然后将其与四维血流磁共振成像数据对齐。然而，由于患者在进行基于屏气的电影磁共振成像采集时的运动和呼吸漂移导致的层间配准误差，这种对齐并不简单。提出了一种基于图像配准的稳健框架来自动减轻这种误差。使用来自 20 名受试者的数据，包括健康志愿者和患者，评估其几何精度和对血流分析的影响。
手动和自动对齐的分割之间观察到高度的空间对应，与未校正的分割相比，对齐的改善具有统计学意义（P<0.01）。手动和自动校正分割的血流分析结果没有显著差异（P>0.05）。
我们的结果证明了所提出方法在改进四维血流磁共振成像中的左心室分割中的有效性，以及其在可靠的血流分析中的潜力。磁共振医学 79:554-560, 2018。© 2017 国际磁共振学会。
