Specialized scanning helps understand the possible effects the virus can have on the brain.
One of the first spectroscopic imaging studies of neurological injuries in COVID-19 Patients have been reported by researchers at Massachusetts General Hospital (MGH) in the United States American Journal of Neuroradiology. When examining six patients with a special magnetic resonance (MR) technique, they found that COVID-19 patients with neurological symptoms have some of the same metabolic disorders in the brain as other patients who are hypoxic (hypoxic) for other reasons are also notable differences.
While it is primarily a respiratory disease, COVID-19 infection affects other organs, including the brain. The disease’s primary effect on the brain is thought to be from hypoxia, but few studies have documented the specific types of damage that characterize COVID-19-related brain injury. Several thousand patients with COVID-19 have been seen at MGH since the outbreak began earlier this year, and this study included results from three of those patients.
The severity of neurological symptoms varies from one of the best known – a temporary loss of smell – to more severe symptoms such as dizziness, confusion, seizures, and stroke. “We were interested in characterizing the biological basis of some of these symptoms,” says Dr. Eva-Maria Ratai, researcher in the Department of Radiology and lead author of the study. “Going forward, we are also interested in understanding the long-term effects of COVID-19, including headaches, fatigue and cognitive impairments. So-called “brain fog” and other impairments that have been found to persist long after the acute phase, ”adds Ratai, also Associate Professor of Radiology at Harvard Medical School.
The researchers used 3 Tesla magnetic resonance spectroscopy (MRS), a special type of scanning sometimes called a virtual biopsy. MRS can identify neurochemical abnormalities even when structural imaging findings are normal. The brains of COVID-19 patients showed a reduction in N-acetyl aspartate (NAA), an increase in choline, and an increase in myo-inositol, similar to those seen in these metabolites in other patients with post-hypoxic white matter abnormalities (leukoencephalopathy) was observed without COVID. One of the patients with COVID-19 who had the most severe white matter damage (necrosis and cavitation) had a particularly marked increase in lactate in MRS, which is another sign of brain damage from a lack of oxygen.
Two of the three COVID-19 patients were intubated in the intensive care unit at the time of imaging, which was part of their treatment. One had COVID-19-associated necrotizing leukoencephalopathy. Another had recently experienced cardiac arrest and showed subtle white matter changes on structural MR. The third had no definite encephalopathy or a recent cardiac arrest. Non-COVID control cases included a patient with white matter damage due to hypoxia for other reasons (post-hypoxic leukoencephalopathy), one with sepsis-related white matter damage, and a normal, age-appropriate, healthy volunteer.
“A key question is whether it is just the decrease in oxygen in the brain that is causing these white matter changes, or whether the virus itself attacks the white matter,” says MGH neuroradiologist Otto Rapalino, MD, who is the first author Harvard shares. MGH postdoc Akila Weerasekera, PhD.
Compared to conventional structural MR imaging, “MRS can better characterize pathological processes such as neuronal injuries, inflammation, demyelination and hypoxia,” adds Weerasekera. “Based on these findings, we believe it can be used as a disease monitoring tool and therapy.”
Reference: “MR spectroscopic findings of the brain in 3 consecutive patients with COVID-19: Preliminary observations” by O. Rapalino, A. Weerasekera, SJ Moum, K. Eikermann-Haerter, BL Edlow, D. Fischer, A. Torrado- Carvajal, ML Loggia, SS Mukerji, PW Schäfer, RG Gonzalez, MH Lev and E.-M. Ratai, October 29, 2020, American Journal of Neuroradiology.
DOI: 10.3174 / ajnr.A6877
The research was supported by the James S. McDonnell Foundation, the National Institutes of Health, and the National Institute of Neurological Disorders and Stroke.
