Brain MRI features of anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis secondary to central nervous system infection in adult patients

Abstract

Background Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis secondary to central nervous system (CNS) infection is a unique subtype of the autoimmune-mediated disease, of which the imaging features are unclear. Purpose To compare the brain magnetic resonance imaging (MRI) features between the anti-NMDAR encephalitis secondary to CNS infection and that without initial infection. Material and Methods A total of 70 adult patients with anti-NMDAR encephalitis were retrospectively enrolled (24 in the post-infection group, 46 in the non-infection-related group). Their clinical and imaging features (lesion distribution, lesion shape, enhancement pattern, brain atrophy) were reviewed and summarized. Lesion distributions were compared between the two groups on lesion probability maps. Results The patients with normal brain MRI scans in the post-infection group were less than those in the non-infection related group (29% vs. 63%; P = 0.0113). Among the 24 patients in the post-infection group, visible lesions were shown at the anti-NMDAR encephalitis onset in 17 patients; lesion distribution was more diffuse than the non-infection-related group, showing higher lesion peak probabilities in the bilateral hippocampus, frontal lobe, temporal lobe, insula, and cingulate. The lesions with contrast enhancement were also more common in the post-infection group than the non-infection-related group (7/13 vs. 2/10). Brain atrophy was observed in eight patients in the post-infection group and three in the non-infection-related group. Conclusion Anti-NMDAR encephalitis secondary to CNS infection has its imaging features—extensive lesion distribution, leptomeningeal enhancement, early atrophy, and necrosis—that could deepen the understanding of the pathophysiology and manifestation of the autoimmune encephalitis besides the classic type.

Cerebral glucose hypometabolism and hypoperfusion of cingulate gyrus: an imaging biomarker of autoimmune encephalitis with psychiatric symptoms

“…This result suggests that the cingulate cortex may be a key region in AE-PS. Notably, cingulate cortex hypometabolism and atrophy have been concurrently reported in AE cases, indicating that cortex atrophy may be a potential mechanism of hypometabolism, especially after chronic neuroinflammation [ 23 , 24 ].…”

Canadian Consensus Guidelines for the Diagnosis and Treatment of Autoimmune Encephalitis in Adults

“…Additionally, MRI can be normal in AIE, particularly when imaging is obtained early. [97][98][99][100] Imaging changes can develop over time, therefore repeat imaging should be considered when the diagnosis is unclear. [97][98][99][100] MRI of the spinal cord should be obtained in cases with symptoms and signs localizing to the spinal cord.…”

“…[97][98][99][100] Imaging changes can develop over time, therefore repeat imaging should be considered when the diagnosis is unclear. [97][98][99][100] MRI of the spinal cord should be obtained in cases with symptoms and signs localizing to the spinal cord. MRI can also be utilized for anatomy-specific malignancy screening as appropriate (e.g., pelvic MRI for ovarian teratoma).…”

The Leading Role of Brain and Abdominal Radiological Features in the Work-Up of Anti-NMDAR Encephalitis in Children: An Up-To-Date Review

“…The brain MRI in patients with NMDARe usually shows a widespread bilateral lesion pattern. Even though inflammation most often affects the hippocampus, abnormalities in the frontal and temporal lobes have also been frequently observed in patients with NMDARe [ 2 , 28 , 30 ]. The presence of bilateral limbic inflammation is considered the only pathognomonic brain MRI feature that can unquestionably lead to the diagnosis of this autoimmune encephalitis, even though an initial negative brain MRI can result [ 19 , 22 ].…”

“…The presence of bilateral limbic inflammation is considered the only pathognomonic brain MRI feature that can unquestionably lead to the diagnosis of this autoimmune encephalitis, even though an initial negative brain MRI can result [ 19 , 22 ]. On the other hand, meningeal enhancement, cortical diffusion restriction, and focal or extensive demyelination are uncommon findings in NMDARe [ 1 , 7 , 30 ]. Many studies have evaluated the relationship between brain MRI lesions and seizures in affected patients [ 28 ].…”