1. Low-field, portable MRI appears to be a feasible neuroimaging option for patients hospitalized in ICUs and unable to be transported for traditional MRI.
2. All cases of point-of-care MRI, except for one, were in agreement with radiologic findings from traditional MRI and CT.
Evidence Rating Level: 2 (Good)
Study Rundown: Magnetic resonance imaging (MRI) technology is a critical component of diagnostics in the field of neurology. Traditional MRI techniques require highly controlled environments and the transport of patients to these environments. However, critically ill patients admitted to the intensive care units (ICUs), including those with coronavirus disease 2019 (COVID-19), cannot be easily or safely transported to these locations. This study sought to investigate the utility of a low-field (0.064-T) portable MRI device for bedside use with ICU patients.
This study of 50 patients in the neuroscience or COVID-19 ICUs at Yale New Haven Hospital examined demographic, clinical, radiological, and treatment data. Radiologic findings of point-of-care (POC) MRI agreed with traditional neuroimaging in nearly all cases, suggesting feasible use of low-field, portable MRI technology with critically ill patients in ICUs. Therefore, POC MRI may allow for adequate diagnosis of neurologic injury, including small ischemic strokes, within complex settings.
In-Depth [ prospective cohort]:
This prospective cohort study focused on admissions to neuroscience or COVID-19 ICUs at Yale New Haven Hospital between October 30, 2019 and May 20, 2020. COVID-19 was diagnosed by positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction nasopharyngeal swab results. Patients were eligible for this study if they presented with neurological alteration or injury, no MRI contraindications, and body habitus less than the scanner’s 30-centimenter vertical opening. The 5-Gauss (0.0005-T) safety perimeter demonstrated a radius of 79 centimeters from the magnet’s center. Collected and analyzed data included demographic, radiological, clinical, and treatment.
Portable MRI examinations were conducted on 50 ICU patients (M [SD] age = 59  years, 32% female). Clinical presentations included COVID-19 with altered mental status (n = 20), hemorrhagic stroke (n = 12), ischemic stroke (n = 9), brain tumor (n = 4), traumatic brain injury (n = 3), and subarachnoid hemorrhage (n = 2). MRIs were completed at a median of 5 days (range = 0 to 37) after ICU admission. T1-weighted, T2-weighted, T2 fluid attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) sequences were collected for 37, 48, 45, and 32 patients, respectively. Of the 30 patients without COVID-19, neuroimaging findings were detected for 29 (97%). A total of 8 of 20 (40%) COVID-19 patients exhibited abnormalities. No adverse events were reported during ICU scanning or portable MRI use.
All POC MRI findings agreed with traditional radiology reports (MRI and computed tomography [CT]), with the exception of one patient who presented with a diffuse subarachnoid hemorrhage not observed on POC MRI (κ= 0.65; p<0.001). One patient in the neuroscience ICU due to a left occipital hemorrhage who was too unstable for transport to traditional MRI demonstrated an undetected small-volume infarction in the context of cardiac arrest. Of the COVID-19 patients, 3 presented with leukoencephalopathy, 3 cerebral infarction, 1 diffuse cerebral edema, and 1 intracranial hemorrhage. All POC MRI findings were in agreement with traditional MRI and CT.
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