The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
NMR Biomed. 2011 Dec;24(10):1313-25. doi: 10.1002/nbm.1693. Epub 2011 May 24.
Arterial cerebral blood volume (CBV(a) ) is a vital indicator of tissue perfusion and vascular reactivity. We extended the recently developed inflow vascular-space-occupancy (iVASO) MRI technique, which uses spatially selective inversion to suppress the signal from blood flowing into a slice, with a control scan to measure absolute CBV(a) using cerebrospinal fluid (CSF) for signal normalization. Images were acquired at multiple blood nulling times to account for the heterogeneity of arterial transit times across the brain, from which both CBV(a) and arterial transit times were quantified. Arteriolar CBV(a) was determined separately by incorporating velocity-dependent bipolar crusher gradients. Gray matter (GM) CBV(a) values (n=11) were 2.04 ± 0.27 and 0.76 ± 0.17 ml blood/100 ml tissue without and with crusher gradients (b=1.8 s/mm(2) ), respectively. Arterial transit times were 671 ± 43 and 785 ± 69 ms, respectively. The arterial origin of the signal was validated by measuring its T(2) , which was within the arterial range. The proposed approach does not require exogenous contrast agent administration, and provides a non-invasive alternative to existing blood volume techniques for mapping absolute CBV(a) in studies of brain physiology and neurovascular diseases.
动脉脑血容量（CBV(a)）是组织灌注和血管反应性的重要指标。我们扩展了最近开发的流入血管空间占有率（iVASO）MRI 技术，该技术使用空间选择性反转来抑制流入切片的血流信号，同时使用控制扫描来测量使用脑脊液（CSF）进行信号归一化的绝对 CBV(a)。采集了多个血液排空时间的图像，以说明脑内动脉通过时间的异质性，从中定量测量 CBV(a)和动脉通过时间。通过包含速度依赖性双极破碎机梯度，分别确定了小动脉 CBV(a)。灰质（GM）CBV(a)值（n=11）分别为 2.04±0.27 和 0.76±0.17ml 血液/100ml 组织，而无和有破碎机梯度（b=1.8s/mm(2)）。动脉通过时间分别为 671±43 和 785±69ms。通过测量其 T(2)验证了信号的动脉来源，其在动脉范围内。该方法不需要外源性造影剂给药，为研究脑生理学和神经血管疾病中绝对 CBV(a)的映射提供了一种非侵入性的替代现有血容量技术。
