Brain MRI Findings in Severe COVID-19: A Retrospective Observational Study

Abstract

Background Brain MRI parenchymal signal abnormalities have been associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Purpose To describe the neuroimaging findings (excluding ischemic infarcts) in patients with severe coronavirus disease 2019 (COVID-19) infection. Materials and Methods This was a retrospective study of patients evaluated from March 23, 2020, to April 27, 2020, at 16 hospitals. Inclusion criteria were (a) positive nasopharyngeal or lower respiratory tract reverse transcriptase polymerase chain reaction assays, (b) severe COVID-19 infection defined as a requirement for hospitalization and oxygen therapy, (c) neurologic manifestations, and (d) abnormal brain MRI findings. Exclusion criteria were patients with missing or noncontributory data regarding brain MRI or brain MRI showing ischemic infarcts, cerebral venous thrombosis, or chronic lesions unrelated to the current event. Categorical data were compared using the Fisher exact test. Quantitative data were compared using the Student t test or Wilcoxon test. P < .05 represented a significant difference. Results Thirty men (81%) and seven women (19%) met the inclusion criteria, with a mean age of 61 years ± 12 (standard deviation) (age range, 8-78 years). The most common neurologic manifestations were alteration of consciousness (27 of 37, 73%), abnormal wakefulness when sedation was stopped (15 of 37, 41%), confusion (12 of 37, 32%), and agitation (seven of 37, 19%). The most frequent MRI findings were signal abnormalities located in the medial temporal lobe in 16 of 37 patients (43%; 95% confidence interval [CI]: 27%, 59%), nonconfluent multifocal white matter hyperintense lesions seen with fluid-attenuated inversion recovery and diffusion-weighted sequences with variable enhancement, with associated hemorrhagic lesions in 11 of 37 patients (30%; 95% CI: 15%, 45%), and extensive and isolated white matter microhemorrhages in nine of 37 patients (24%; 95% CI: 10%, 38%). A majority of patients (20 of 37, 54%) had intracerebral hemorrhagic lesions with a more severe clinical presentation and a higher admission rate in intensive care units (20 of 20 patients [100%] vs 12 of 17 patients without hemorrhage [71%], P = .01) and development of the acute respiratory distress syndrome (20 of 20 patients [100%] vs 11 of 17 patients [65%], P = .005). Only one patient had SARS-CoV-2 RNA in the cerebrospinal fluid. Conclusion Patients with severe coronavirus disease 2019 and without ischemic infarcts had a wide range of neurologic manifestations that were associated with abnormal brain MRI scans. Eight distinctive neuroradiologic patterns were described. © RSNA, 2020.

Figure 1.

Flowchart of patient inclusion and exclusion

Figure 2.

Axial FLAIR in four different COVID-19 patients. A) 58-year old man with impaired consciousness: FLAIR hyperintensities located in the left medial temporal lobe. B) 66-year old man with impaired consciousness: FLAIR ovoid hyperintense lesion located in the central part of the splenium of the corpus callosum. C) 71-year old woman with pathological wakefulness after sedation: extensive and confluent supratentorial white matter FLAIR hyperintensities (arrows). Association with leptomeningeal enhancement (stars) D) 61-year old man with confusion: hyperintense lesions involving both middle cerebellar peduncles.

Figure 3.

65-year old man with pathological wakefulness after sedation. Non-confluent multifocal white matter hyperintense lesions on FLAIR and diffusion, with variable enhancement, and hemorrhagic lesions. Axial Diffusion (A, B), Apparent Diffusion Coefficient (ADC) map (C), axial FLAIR (D, E), sagittal FLAIR (F), axial Susceptibility weighted imaging (SWI) (G), and postcontrast T1 weighted MR images (H). Multiple nodular hyperintense Diffusion and FLAIR lesions localized in the white matter including the corpus callosum (F). Some of them (white arrow) are associated with reduced ADC corresponding to cytotoxic edema (C). Other lesions are located next to the lenticular nucleus (cross) (E, G, H), with hemorrhagic changes (G), and enhancement after contrast administration.

Figure 4.

57-year old man with pathological wakefulness after sedation. Extensive and isolated white matter microhemorrhages. Axial Susceptibility weighted imaging (SWI) (A, B, C, D): multiple microhemorrhages mainly affecting the subcortical white matter, corpus callosum, internal capsule, and cerebellar peduncles.

Figure 5.

54-year old man with pathological wakefulness after sedation. Non-confluent multifocal white matter hyperintense lesions on FLAIR and diffusion, with variable enhancement. Axial Diffusion (A, B), Apparent Diffusion Coefficient (ADC) map (C, D), axial postcontrast FLAIR (E, F), and postcontrast T1 weighted MR images (G, H). Multiple nodular hyperintense Diffusion and FLAIR subcortical and corticospinal tracts lesions, with very mild mass effect on adjacent structures. The lesions present a center with an elevation of ADC corresponding to vasogenic edema and a peripheral ring of reduced ADC corresponding to cytotoxic edema (C, D). After contrast administration, small areas of very mild enhancement are detected (G, H).

Figure 6.

51-year old man with impaired consciousness. Acute necrotizing encephalopathy. Axial FLAIR (A, C, D), and coronal FLAIR (B): bilateral FLAIR hyperintensity (cross) in both thalami (A, B), associated with involvement of the cerebellar (C), and cerebral (D) white matter (arrows).