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Research and Development of quantitative CBF measurement with MRI

MRI定量CBF测量的研究与发展

基本信息

批准号：
14571309
负责人：
SHIINO Akihiko
金额：
$ 2.11万
依托单位：
Shiga University of Medical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14571309/
关键词：
perfusion cerebral blood flow dynamic susceptibility contrast infarction magnetic resonance brain ischemia quantification 脳循環代謝脳血流定量 MRI DSC

项目摘要

Quantitative measurement of CBF by dynamic dynamic susceptibility contrast(DSC) technique is an important and challenging examination. For quantification of rCBF value on pixel-by-pixel basis, the arterial input function(AIF) has to be measured. The limited spatial resolution associated with the EPI sequences can potentially lead to inaccuracy and variability in the CBF measurements. In this study, a correction scheme is proposed to correct the errors. Subjects were studied with both MR and PET so that the accuracy of MR measured CBF can be assessed.Five healthy volunteers were studied. All MR images were acquired on a General Electric 1.5 Signa clinical scanner. Since single shot EPI sequence provide only a very low bandwidth in phase encoding direction leading to prominent signal misregistration, we used multishot EPI technique which minimized the signal loss or distortion. All images were transferred to a SGI Workstation for post-processing. The AIF and venous output function(VOF) w … More ere automatically obtained from large basal artery (IC or MCA or PCA) and the superior sagittal sinus, respectively. FT was employed to deconvolve the tissue function by the experimentally measured AIF and thus quantitative estimate of CBF was obtained. The AIF of each subject was corrected by the VOF, which was also obtained by integrating the delta-R_2^* curve obtained from the superior sagittal sinus. For normalization of the position between the MRI and the PET, three-dimensional anatomical fitting was performed.A total of 100 circular ROIs in each subject were placed in both the PET and MR CBF maps and were used to obtain regional estimate of CBF. As a result, there was good correlation in the CBF values among the two modalities (correlation coefficient=0.8) with the exception of the area including large vessels.Although several factors can potentially account for the observed variability in this study, the most plausible explanations are the partial volume effects of the AIF caused by the limited spatial resolution of the EPI sequence. The areas of AIF may be underestimated, leading to an overestimation as well as variability in the CBF measurement. We made an assumption that the integral of the delta-R_2^* curve of both the AIF and the VOF should be equal. The VOF corrected the partial volume effect and variables came from the AIF selection. In summary, we have presented an improved partial volume correction method, which reduces the errors in AIF determination. Less

动态磁化率对比（DSC）技术定量测定脑血流是一项重要而又具有挑战性的研究。为了逐像素定量rCBF值，必须测量动脉输入功能（AIF）。与EPI序列相关的有限空间分辨率可能会导致CBF测量的不准确性和可变性。在这项研究中，提出了一个修正方案，以纠正错误。受试者进行了研究与MR和PET，使MR测量CBF的准确性可以评估。所有MR图像均在General Electric 1.5 Signa临床扫描仪上采集。由于单次激发EPI序列在相位编码方向上提供的带宽很低，导致信号配准不良，因此我们采用了多次激发EPI技术，最大限度地减少了信号的损失或失真。将所有图像传输到SGI工作站进行后处理。AIF和静脉输出功能（VOF） ...更多信息分别从大基底动脉（IC或MCA或PCA）和上级矢状窦自动获得。采用傅立叶变换对实验测得的AIF进行组织功能的反卷积，从而获得CBF的定量估计。VOF也是通过积分上级矢状窦的delta-R_2^* 曲线得到的。为使MRI和PET的位置标准化，对每例受试者进行三维解剖学拟合，在PET和MR脑血流图上分别放置100个圆形感兴趣区，以获得脑血流的区域估计值。因此，有很好的相关性，在CBF值之间的两种方式（相关系数=0.8），除了该地区，包括大vessel.Although几个因素可以潜在地解释在这项研究中观察到的变异性，最合理的解释是部分容积效应的AIF所造成的有限的空间分辨率的EPI序列。AIF的面积可能被低估，导致高估以及CBF测量的变异性。我们假设AIF和VOF的δ-R_2^* 曲线的积分相等。VOF校正了部分容积效应，变量来自AIF选择。总之，我们提出了一种改进的部分体积校正方法，它减少了AIF测定的误差。少