Diminished cerebral oxygen extraction and metabolic rate in sickle cell disease using T2 relaxation under spin tagging MRI.
Diminished cerebral oxygen extraction and metabolic rate in sickle cell disease using T2 relaxation under spin tagging MRI.
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DOI：
10.1002/mrm.27015
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发表时间：
2018-07
影响因子：
3.3
通讯作者：
Wood JC
中科院分区：
文献类型：
--
作者：
Bush AM;Coates TD;Wood JC
T2 MRI血氧仪可以无创伤地测定血氧饱和度(Y)，但需要经验MR校准模型将测量的血液横向弛豫（T2b）转换为Y。现有T2b模型在镰状细胞病（SCD）等血液疾病存在时的准确性尚不清楚。采用Carr Purcell Meiboom Gill T2制备序列对11例SCD患者进行83次全血测定，建立离体血红蛋白S (HbS) T2b模型。对37例健康对照和33例SCD患者（年龄24.6±10.2岁）进行前臂静脉血气、矢状窦T2 （T2舒张Under Spin Tagging）和脑总血流量（MRI）的测量。脑氧饱和度、提取分数和代谢率估计使用三个单独的T2b模型计算。比较大脑和前臂氧提取分数。离体SCD血比对照血具有更大的饱和依赖性松弛度，对HbS依赖性较弱，对红细胞压积无依赖性。在体内，HbS T2b模型预测的Yv值变异系数最低（与现有的T2b模型相比），与外周静脉血氧饱和度的相关性最强（r2= 0.29）。HbS T2b模型预测SCD患者的Yv测量值系统性更高（73±5和61±6，p<0.0001），外周静脉测量值也反映了这一点（75±20和45±20，p<0.0001）。SCD患者的大脑和外周氧提取减少，提示血流量增加超过代谢需求或存在生理性动静脉分流。
T2 MRI oximetry can non-invasively determine oxygen saturation (Y) but requires empirical MR calibration models to convert the measured blood transverse relaxation (T2b) into Y. The accuracy of existing T2b models in the presence of blood disorders such as sickle cell disease (SCD) remains unknown. A Carr Purcell Meiboom Gill T2 preparation sequence was used to make 83 whole blood measurements from 11 subjects with SCD in order to derive an ex-vivo hemoglobin S (HbS) T2b model. Forearm venous blood gas, sagittal sinus T2 (T2 Relaxation Under Spin Tagging) and total brain blood flow (phase contrast MRI) were measured in 37 healthy controls and 33 SCD subjects (age 24.6 ± 10.2 years). Cerebral oxygen saturation, extraction fraction and metabolic rate estimates were calculated using three separate T2b models. Cerebral and forearm oxygen extraction fraction were compared. Ex-vivo, SCD blood had greater saturation dependent relaxivity than control blood, with a weak dependence on HbS and no dependence on hematocrit. In-vivo, the HbS T2b model predicted Yv values with lowest coefficient of variation (compared to existing T2b models) and the strongest correlation with peripheral venous oximetry (r2=.29). The HbS T2b model predicted systematically higher Yv measurements in SCD patients (73 ± 5 and 61 ± 6, p<0.0001) which was mirrored by peripheral venous measurements (75 ± 20 and 45 ± 20, p<0.0001). Cerebral and peripheral oxygen extraction are decreased in SCD patients, suggesting either blood flow is increased beyond metabolic demands or the presence of physiological arterial-venous shunting.
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影响因子：
--
作者：
Eaton, W A;Hofrichter, J
通讯作者：
Hofrichter, J
影响因子：
6.3
作者：
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DOI：
10.1097/00004647-199701000-00009
发表时间：
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影响因子：
6.3
作者：
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通讯作者：
Frank, LR
影响因子：
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影响因子：
15.9
作者：
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通讯作者：
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