Stratification of heterogeneous diffusion MRI ischemic lesion with kurtosis imaging: evaluation of mean diffusion and kurtosis MRI mismatch in an animal model of transient focal ischemia.
Stratification of heterogeneous diffusion MRI ischemic lesion with kurtosis imaging: evaluation of mean diffusion and kurtosis MRI mismatch in an animal model of transient focal ischemia.
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DOI：
10.1161/strokeaha.112.661926
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发表时间：
2012-08
期刊：
影响因子：
8.3
通讯作者：
Sun PZ
中科院分区：
文献类型：
--
作者：
Cheung JS;Wang E;Lo EH;Sun PZ
缺血性组织损伤具有异质性，导致在广泛应用的扩散加权磁共振成像(DWI)中表现出复杂的模式。我们研究了短暂性大脑中动脉闭塞(MCAO)动物模型的弥散峰度成像(DKI)的时空特征。成年雄性Wistar大鼠(N=18)行大脑中动脉阻塞90min。分别在大脑中动脉阻塞时和再灌注后20min进行多参数磁共振成像，在6个扩散梯度方向上取S/mm~2250~3000的8个b值进行弥散加权成像。扩散和峰状病变由两名独立的研究人员在混洗图像中勾勒出来。在大脑中动脉闭塞后24小时行T2磁共振检查以评估卒中结果。平均弥散(MD)灶占脑片的百分比(23.5±8.1%)显著大于平均峰度(MK)灶(13.2±2.0%)。再灌注后MD病变明显缩小(13.8±4.3%)，而MK病变变化不大(13.0±2.5%)，病变大小差异无统计学意义。我们证明，MD/MK失配在再灌注后恢复良好，而同时存在MD和MK缺陷的区域恢复较差。DKI可能有助于对不同类型的DWI病变进行分层，以加强对缺血性组织损伤的定性。
Ischemic tissue damage is heterogeneous, resulting in complex patterns in the widely used diffusion-weighted MRI (DWI). Our study examined the spatiotemporal characteristics of diffusion kurtosis imaging (DKI) in an animal model of transient middle cerebral artery occlusion (MCAO). Adult male Wistar rats (N = 18) were subjected to 90min MCAO. Multi-parametric MRI were obtained during MCAO and 20 min after reperfusion, with DWI obtained using eight b-values from 250 to 3000 s/mm2 in six diffusion gradient directions. Diffusion and kurtosis lesions were outlined in shuffled images by two investigators independently. T2 MRI was obtained 24 hr after MCAO to evaluate stroke outcome. Mean diffusion (MD) lesion (23.5±8.1%, percentage of the brain slice) was significantly larger than mean kurtosis (MK) lesion (13.2±2.0%) during MCAO. MD lesion decreased significantly after reperfusion (13.8±4.3%) while MK lesion showed little change (13.0±2.5%), with their lesion size difference being insignificant. We demonstrated that MD/MK mismatch recovered reasonably well upon reperfusion while regions with concurrent MD and MK deficits showed poor recovery. DKI may help stratify heterogeneous DWI lesion for enhanced characterization of ischemic tissue injury.