Table 2.
Demyelination-related MRI findings in COVID and post-COVID patients.
| MRI Technology | Time from Onset | Neurologic Symptoms/Diagnosis | Demyelination/ Sample Size |
Demyelination-Related MRI Findings | Reference |
|---|---|---|---|---|---|
| T2-FLAIR, T1w, DTI (FA) |
3 months after COVID-19 | No specific neurological manifestations at the acute stage | 19 mild, 32 severe/82 | No obvious lesions on the conventional MRI, decreases in volume, length, and the mean FA in subcortical WM tracts in severe compared to mild patients, and in mild patients compared to controls |
Qin et al. [5] |
| Conventional MRI, 3D T1w, 3D-pcASL, DTI (FA) | 3–10 months after COVID-19 | No specific neurological manifestations at the acute stage | 13 mild, 21 severe/34 | The trends in volume of subcortical nuclei and white matter tracts were different for 3–10 months period in patients with mild and severe COVID-19 | Tian et al. [57] |
| T1w, Gd-T1w FLAIR, DWI, ADC | Acute COVID-19 | Late awakening after withdrawal of sedation, acute neurologic symptoms | 5/73 (7%) | Multiple bilateral WM deep and periventricular, corpus callosum and basal ganglia lesions in patients with severe COVID-19 | Chougar et al. [151] |
| T1w, Gd-T1w T2/FLAIR | Acute COVID-19 | Acute neurologic symptoms during hospital stay | 1/20 (5%) | MS plaque exacerbation | Mahammedi et al. [152] |
| 7/20 (35%) | Nonspecific T2/FLAIR hyperintensity | ||||
| 3/20 (15%) | Subcortical white matter lesions | ||||
| T2w, DWI, FLAIR, SWI | Acute COVID-19 | Agitation, spatial disorientation, seizure/Subacute encephalopathy | 4/21 (19%) | Multifocal laminar cortical brain lesions detected by FLAIR hyperintensity | Anzalone et al. [154] |
| DWI, SWI, T2w, FLAIR, | Acute COVID-19 | Abnormal mental status/ Thromboembolism, microbleeds, arterial microvascular thrombosis |
4/* | Mild FLAIR hyperintensity along some cortical regions | Nicholson et al. [155] |
| T1W, Gd-T1w, DWI, gradient-echo T2, SWI, FLAIR | Acute COVID-19 | Alteration of consciousness, pathological wakefulness, confusion, agitation | 11/37 (30%) | Non-confluent multifocal WM hyperintense lesions on FLAIR with variable enhancement | Kremer et al. [156] |
| T2W, DWI, FLAIR | Acute COVID-19 | Diminished mental status/Diffuse leukoencephalopathy | 10/27 (37%) | Abnormal T2 hyperintensities bilateral deep and subcortical WM | Radmanesh et al. [157] |
| FLAIR, SWI, DWI, MRA | Acute COVID-19 | De novo acute neurologic symptoms/Encephalopathy (74%), acute necrotizing encephalopathy (7%), and vasculopathy (19%). | 6/27 (22%) | FLAIR hyperintensities in deep WM, the corpus callosum, and the basal ganglia | Scullen et al. [158] |
| SWI, DWI, Gd- DSC-PWI, ASL-PWI, T2w, Gd-T2w, FLAIR, Gd- FLAIR, T1w/TSE, Gd-T1w/TSE, T1w/GRE IR, Gd-T1w/GRE IR MRA | Acute COVID-19 and follow up | Acute neurologic symptoms during hospital stay/leukoencephalopathy, encephalopathy, hypoxic/metabolic changes, encephalitis | 23/41 (53%) | Confluent, symmetric, periventricular juxtacortical WM lesions, changes in cerebellar peduncles, corpus callosum, olfactory bulbs and tracts | Klironomos et al. [159] |
| FLAIR, SWI, DWI, MRA | Long COVID-19 | Smell and taste dysfunction, vertigo, headache, dizziness, fatigue | 16 mild, 23 moderate/39 (100%) |
Hyperintense lesions on FLAIR, microhemorrhage on SWI | Marcic et al. [160] |
* A total number of examined patients have not been specified. Note. ASL-PWI-arterial spin labeling, DWI-diffusion-weighted imaging, PWI-perfusion-weighted imaging, DSC-PWI-Dynamic susceptibility contrast perfusion, DTI-diffusion-tensor imaging, FA-fractional anisotropy, FLAIR-fluid-attenuated inversion recovery, Gd-gadolinium-based contrast agent, GRE-gradient-recalled echo, IR-inversion recovery, SWI-susceptibility-weighted imaging, 3D-three-dimensional, GRE-gradient-recalled echo, TSE-turbo spin echo, IR-inversion recovery, MRA-magnetic resonance angiography, WM -white matter.