Diffusion kurtosis imaging and diffusion tensor imaging parameters applied to white matter and gray matter of patients with anti-N-methyl-D-aspartate receptor encephalitis

Abstract

ObjectivesTo compare parameters of diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) to evaluate which can better describe the microstructural changes of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients and to characterize the non-Gaussian diffusion patterns of the whole brain and their correlation with neuropsychological impairments in these patients.Materials and methodsDTI and DKI parameters were measured in 57 patients with anti-NMDAR encephalitis and 42 healthy controls. Voxel-based analysis was used to evaluate group differences between white matter and gray matter separately. The modified Rankin Scale (mRS) was used to evaluate the severity of the neurofunctional recovery of patients, the Montreal Cognitive Assessment (MoCA) was used to assess global cognitive performance, and the Hamilton Depression Scale (HAMD) and fatigue severity scale (FSS) were used to evaluate depressive and fatigue states.ResultsPatients with anti-NMDAR encephalitis showed significantly decreased radial kurtosis (RK) in the right extranucleus in white matter (P < 0.001) and notably decreased kurtosis fractional anisotropy (KFA) in the right precuneus, the right superior parietal gyrus (SPG), the left precuneus, left middle occipital gyrus, and left superior occipital gyrus in gray matter (P < 0.001). Gray matter regions with decreased KFA overlapped with those with decreased RK in the left middle temporal gyrus, superior temporal gyrus (STG), supramarginal gyrus (SMG), postcentral gyrus (POCG), inferior parietal but supramarginal gyrus, angular gyrus (IPL) and angular gyrus (ANG) (P < 0.001). The KFA and RK in the left ANG, IPL and POCG correlated positively with MoCA scores. KFA and RK in the left ANG, IPL, POCG and SMG correlated negatively with mRS scores. KFA in the left precuneus and right SPG as well as RK in the left STG correlated negatively with mRS scores. No significant correlation between KFA and RK in the abnormal brain regions and HAMD and FSS scores was found.ConclusionThe microstructural changes in gray matter were much more extensive than those in white matter in patients with anti-NMDAR encephalitis. The brain damage reflected by DKI parameters, which have higher sensitivity than parameters of DTI, correlated with cognitive impairment and the severity of the neurofunctional recovery.

Multiple diffusion metrics in differentiating solid glioma from brain inflammation

“…In DKI model, MK value reflects the complexity and structural integrity of brain tissue ( Das et al, 2017 ). Previous studies on the application of DKI to low-grade gliomas ( Goryawala et al, 2018 ) and inflammation ( Liu et al, 2022 ) have demonstrated lower radial kurtosis (RK) values in lesions in comparison to healthy controls or contralateral normal-appearing white matter, which related to the destructive impact exerted by tumor cells or inflammation on brain tissue. In our research, the values of MK in glioma were lower, suggesting more severe structural damage in glioma than inflammatory lesions.…”

Impaired functional connectivity of the hippocampus in translational murine models of NMDA-receptor antibody associated neuropsychiatric pathology

“…In addition, extensive white matter damage assessed by diffusion tensor imaging related to disease severity and cognitive impairment has been previously reported in NMDAR encephalitis patients [ 6 , 48 – 50 ]. Moreover, a recent diffusion kurtosis imaging study also reported extensive gray matter microstructural damage in patients with NMDAR encephalitis [ 51 ]. Together, these studies indicate brain-wide dysfunction of NMDA receptors, with predominant alteration of hippocampal function.…”

Neural Surface Antibodies and Neurodegeneration: Clinical Commonalities and Pathophysiological Relationships

“…However, brain structural and functional abnormalities in NMDAR encephalitis seems to extend beyond hippocampus. A number of recent works using different MR techniques as DTI, diffusion kurtosis imaging, voxel-based morphometry (VBM) and surface-based morphometry disclosed diffuse structural changes in hemispheric WM and cortical and subcortical GM, with correlation with cognitive scores ( Table 3 ) [ 117 , 118 , 119 , 120 , 121 ]. Accordingly, network analysis of resting-state fMRI data in patients with post-acute NMDAR encephalitis revealed alterations in whole-brain functional connectivity including impairment of the connectivity between the hippocampus and the medial temporal lobe (MTL) and the DMN, and significant reductions in intranetwork connectivity within the MTL, sensorimotor, lateral-temporal, and visual networks [ 122 ].…”