麻豆传媒

CHICAGO -- A specialized type of MRI showed lingering brain abnormalities in patients up to 6 months after they recovered from COVID-19.

Data from susceptibility-weighted MRI in 46 COVID-recovered patients and 30 healthy controls showed that the former had significantly higher susceptibility values in regions of the frontal lobe and brain stem, according to Vidur Mahajan, MBBS, MBA, CEO of CARPL.ai of San Francisco and New Delhi.

In the post-COVID patients (age about 35), clusters obtained in the frontal lobe primarily showed differences in the white matter regions. Additionally, portions of left and right orbito-inferior frontal gyrus, along with respective adjacent white matter areas, constituted the two clusters, and there was a significant cluster in the right ventral diencephalon region of the brain stem, he said in a presentation at the Radiological Society of North America (RSNA) annual meeting.

"These brain regions are linked with fatigue, insomnia, anxiety, depression, headaches, and cognitive problems," explained co-investigator Sapna Mishra, a PhD candidate at the Indian Institute of Technology in Delhi, in a . COVID-recovered study patients reported symptoms of fatigue, trouble sleeping, lack of attention, and memory issues.

These abnormalities did not appear in the brains of the controls (age about 34), noted Mahajan, who presented the results on behalf of Mishra, who was unable to attend RSNA due to visa issues.

"Group-level studies have not previously focused on COVID-19 changes in magnetic susceptibility of the brain despite several case reports signaling such abnormalities," Mishra stated in the release. "Our study highlights this new aspect of the neurological effects of COVID-19 and reports significant abnormalities in COVID survivors. Changes in susceptibility values of brain regions may be indicative of local compositional changes."

Mahajan added that the study "observations are consistent with results reported in the literature of single-patient case studies carried out on susceptibility-weighted image volumes. The present research will help the community to understand the impact of SARS-CoV-2 virus on the human brain."

RSNA session co-moderator Jason Allen, MD, PhD, of Emory University in Atlanta, told 麻豆传媒 that the findings show that "COVID patients should be coming back for further evaluation with imaging because a lot of these long-COVID symptoms can be subtle and may come out over time."

He noted that there may be worse progression for people with Alzheimer's disease or a history of diabetes. Similarly, previous COVID infection may result in worse outcomes of other diseases, he said.

However, Allen said that combining susceptibility-weighted MRI with could offer more information about these brain abnormalities.

"At this point, we really don't know what we are seeing with these images," he stated. "There have been studies showing that COVID does cause some , so it is not surprising to see these micro-hemorrhages. We can speculate that people [who] have problems with smell ... that COVID could be in the olfactory region, which is in the frontal lobe regions. But it may be that COVID is driving cognitive changes and executive function, and things like that."

He said "it would also be interesting to look at patients who have long-COVID symptoms and see if they are showing the same findings, or if there are different areas affected in these patients."

The researchers explained that the COVID patients were imaged within 6 months of their recovery. For the MRIs, there was a preprocessing step, and the susceptibility-weighted MRI volumes were registered to the , followed by signal intensity normalization.

According to the release, "magnetic susceptibility denotes how much certain materials, such as blood, iron and calcium, will become magnetized in an applied magnetic field. This ability aids in the detection and monitoring of a host of neurologic conditions including microbleeds, vascular malformations, brain tumors and stroke."

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