In vivo 1H2O T2† measurement in the human occipital lobe at 4T and 7T by Carr-Purcell MRI:: Detection of microscopic susceptibility contrast
In vivo 1H2O T2† measurement in the human occipital lobe at 4T and 7T by Carr-Purcell MRI:: Detection of microscopic susceptibility contrast
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DOI：
10.1002/mrm.10112
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发表时间：
2002-04-01
影响因子：
3.3
通讯作者：
Garwood, M
中科院分区：
文献类型：
--
作者：
Bartha, R;Michaeli, S;Garwood, M
提出了一种高分辨率自旋回波成像方法（称为CP-LASER），该方法利用绝热Carr-Purcell（CP）脉冲序列的自旋重聚焦能力来测量表观（H2O）-H-1横向弛豫（T-2（+））并基于微观组织磁化率产生对比度。在4 T和7 T条件下，分别对6名和8名受试者在4个不同回波时间下采集了人枕叶的高分辨率CP-激光图像，以研究磁场强度（B-o）和CP脉冲间隔时间（tau（cp））对T-2（+）的影响。确定了敏感性对比，并对灰质、白色物质和脑脊液中的长tau（cp）（>10 ms）和短tau（cp）（4 T时为7 ms，7 T时为6 ms）的T-2（+）进行了定量。灰、白色物质的（H_2O）-H ~（-1）弛豫速率常数（1/T ~（-2）（+））均随场强的增加而近似线性增加，T ~（-2）（+）与τ（cp）呈负相关。在4 T和7 T时，灰质的平均T-2（+）值分别比白色小19%和9%。这些结果与脑灰质中与白色物质相比更高水平的区室化铁蛋白和增加的血容量一致。(C)2002 Wiley-Liss，Inc.
A high-resolution spin-echo imaging method is presented (called CP-LASER) which exploits the spin refocusing capability of an adiabatic Carr-Purcell (CP) pulse sequence to measure apparent (H2O)-H-1 transverse relaxation (T-2(+)) and generate contrast based on microscopic tissue susceptibility. High-resolution CP-LASER images of the human occipital lobe were acquired at four different echo times from six subjects at 4T and eight subjects at 7T to investigate the effect of magnetic field strength (B-o) and the CP interpulse time (tau(cp)) on T-2(+). Susceptibility contrast was identified and T-2(+) was quantified for long tau(cp) (>10 ms) and short tau(cp) (7 ms at 4T and 6 ms at 7T) in gray matter, white matter, and cerebral spinal fluid. The (H2O)-H-1 relaxation rate constants (1/T-2(+)) of gray and white matter each increased approximately linearly with field strength and T-2(+) was inversely related to tau(cp). The average T-2(+) value of gray matter was 19% and 9% smaller than that of white matter at 4T and 7T, respectively. These results are consistent with higher levels of compartmentalized ferritin and increased blood volume in gray matter compared to white matter in this region of the brain. (C) 2002 Wiley-Liss, Inc.