Bester M, Jensen J H, Babb J S, Tabesh A, Miles L, Herbert J, Grossman R I, Inglese M
Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Hamburg-Eppendorf (UKE), Germany/ Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA.
Department of Radiology and Radiological Science, Medical University of South Carolina, USA.
Mult Scler. 2015 Jun;21(7):935-44. doi: 10.1177/1352458514556295. Epub 2014 Nov 12.
Non-Gaussian diffusion imaging by using diffusional kurtosis imaging (DKI) allows assessment of isotropic tissue as of gray matter (GM), an important limitation of diffusion tensor imaging (DTI).
In this study, we describe DKI and DTI metrics of GM in multiple sclerosis (MS) patients and their association with cognitive deficits.
Thirty-four patients with relapsing-remitting MS and 17 controls underwent MRI on a 3T scanner including a sequence for DKI with 30 diffusion directions and 3b values for each direction. Mean kurtosis (MK), mean diffusivity and fractional anisotropy (FA) of cortical and subcortical GM were measured using histogram analysis. Spearman rank correlations were used to characterize associations among imaging measures and clinical/neuropsychological scores.
In cortical GM, a significant decrease of MK (0.68 vs. 0.73; p < 0.001) and increase of FA (0.16 vs. 0.13; p < 0.001) was found in patients compared to controls. Decreased cortical MK was correlated with poor performance on the Delis-Kaplan Executive Function System test (r = 0.66, p = 0.01).
Mean kurtosis is sensitive to abnormality in GM of MS patients and can provide information that is complementary to that of conventional DTI-derived metrics. The association between MK and cognitive deficits suggests that DKI might serve as a clinically relevant biomarker for cortical injury.
使用扩散峰度成像(DKI)进行的非高斯扩散成像能够评估诸如灰质(GM)等各向同性组织,这是扩散张量成像(DTI)的一个重要局限。
在本研究中,我们描述了复发缓解型多发性硬化(MS)患者灰质的DKI和DTI指标及其与认知缺陷的关联。
34例复发缓解型MS患者和17名对照者在3T扫描仪上接受了MRI检查,包括一个具有30个扩散方向且每个方向有3个b值的DKI序列。使用直方图分析测量皮质和皮质下灰质的平均峰度(MK)、平均扩散率和分数各向异性(FA)。采用Spearman等级相关性分析来描述成像指标与临床/神经心理学评分之间的关联。
与对照组相比,患者皮质灰质中MK显著降低(0.68对0.73;p < 0.001),FA升高(0.16对0.13;p < 0.001)。皮质MK降低与Delis-Kaplan执行功能系统测试表现不佳相关(r = 0.66,p = 0.01)。
平均峰度对MS患者灰质异常敏感,可提供与传统DTI衍生指标互补的信息。MK与认知缺陷之间的关联表明DKI可能作为皮质损伤的临床相关生物标志物。