3D phase contrast MRI: Partial volume correction for robust blood flow quantification in small intracranial vessels
3D phase contrast MRI: Partial volume correction for robust blood flow quantification in small intracranial vessels
复制标题
DOI：
10.1002/mrm.26637
复制
发表时间：
2018-01-01
影响因子：
3.3
通讯作者：
Vargas, Maria I.
中科院分区：
文献类型：
--
作者：
Bouillot, Pierre;Delattre, Benedicte M. A.;Vargas, Maria I.
目的3D-PCMRI（相衬MRI）序列的最新进展允许测量大脑动脉的复杂血流动力学。然而，这些血管的小尺寸与空间分辨率会导致不可忽略的部分体积伪影，在计算血流速率时必须考虑到这一点。为此，我们将3D- pcmri提供的流速信息与3DTOF（飞行时间MRI）或3DRA （3D旋转血管造影）测量的血管几何形状相结合，以纠正流速评估中的部分体积效应。方法首先在体外圆柱形血管和患者特异性血管上进行了完全控制脉动血流的实验。研究人员对2D和3D-PCMRI测量结果进行了分析，并将其与流量计基线进行了比较，这些测量结果使用的空间分辨率从20到1.3体素不等。其次，对35例内颈动脉（ICA）动脉瘤患者进行体内3DTOF、2D和3D-PCMRI测量，这些患者需要3DRA成像进行血管内治疗。结果采用部分体积校正的体外2D和3D-PCMRI平均流量对每血管直径约2体素以上的采集分辨率的敏感性很低，而未校正的流量在降低空间分辨率时出现严重偏差。在ICA中测量的体内3D-PCMRI流量与2D-PCMRI数据非常吻合，并且在C7分岔处观察到良好的流量守恒。在全球范围内，大部分已发表的关于颅内血流的研究报告显示，部分体积校正导致的流量比未校正值低10-15%。结论部分容积校正可提高PCMRI流量测量的准确性，尤其是颅内动脉等小血管。中华医学杂志（英文版），2018。(c) 2017年国际医学磁共振学会。
PurposeRecent advances in 3D-PCMRI (phase contrast MRI) sequences allow for measuring the complex hemodynamics in cerebral arteries. However, the small size of these vessels vs spatial resolution can lead to non-negligible partial volume artifacts, which must be taken into account when computing blood flow rates. For this purpose, we combined the velocity information provided by 3D-PCMRI with vessel geometry measured with 3DTOF (time of flight MRI) or 3DRA (3D rotational angiography) to correct the partial volume effects in flow rate assessments.MethodsThe proposed methodology was first tested in vitro on cylindrical and patient specific vessels subject to fully controlled pulsatile flows. Both 2D- and 3D-PCMRI measurements using various spatial resolutions ranging from 20 to 1.3 voxels per vessel diameter were analyzed and compared with flowmeter baseline. Second, 3DTOF, 2D- and 3D-PCMRI measurements were performed in vivo on 35 patients harboring internal carotid artery (ICA) aneurysms indicated for endovascular treatments requiring 3DRA imaging.ResultsThe in vitro 2D- and 3D-PCMRI mean flow rates assessed with partial volume correction showed very low sensitivity to the acquisition resolution above approximate to 2 voxels per vessel diameter while uncorrected flow rates deviated critically when decreasing the spatial resolution. 3D-PCMRI flow rates measured in vivo in ICA agreed very well with 2D-PCMRI data and a good flow conservation was observed at the C7 bifurcation. Globally, partial volume correction led to 10-15% lower flow rates than uncorrected values as those reported in most of the published studies on intracranial flows.ConclusionPartial volume correction may improve the accuracy of PCMRI flow rate measurements especially in small vessels such as intracranial arteries. Magn Reson Med 79:129-140, 2018. (c) 2017 International Society for Magnetic Resonance in Medicine.