麻豆传媒

A bedside low-field MRI scanner proved its mettle in Yale New Haven Hospital's ICU, including for COVID-19 patients, clinicians there reported.

Among 50 patients scanned in their ICU, the Hyperfine's identified neuroimaging abnormalities for eight of the 20 on ventilation for COVID-19 (40%) and 29 of the 30 without COVID-19 (97%).

The only disagreement between the point-of-care findings and available conventional radiology reports was one case of diffuse subarachnoid hemorrhage that the device didn't pick up, Kevin N. Sheth, MD, of Yale University School of Medicine in New Haven, Connecticut, and colleagues .

But the device picked up an extra finding -- a small-volume infarction in a patient with cardiac arrest "who was too unstable to be transported to conventional imaging," the group noted.

No adverse events or complications occurred with the device or in-room scanning. No ICU equipment had to be removed from the room; the MRI imaging operator and bedside nurse remained in the room for the 0.064-T scans.

The Swoop MRI device, which was last month for bedside use, wheels to the patient's bedside, plugs into a standard electrical outlet, and is controlled through a wireless tablet.

"It's exciting to see essential diagnostic testing being brought to the bedside of critically ill patients. Any time we need to transport an unstable patient out of the ICU for a study, we are taking a risk and potentially exposing others to a communicable disease," commented critical care physician Robert Dickson, MD, of the University of Michigan School of Medicine in Ann Arbor.

However, the portable device itself could be a source of infection if not well sanitized between patients, noted Ali Seifi, MD, director of neuro critical care at the University of Texas Health at San Antonio.

In the study, disinfectant was used to clean the device after each scan. But because the portable MRI scanners "have lots of parts and recesses, it's not that easy" to do surface cleaning, Seifi suggested. UV disinfection could be better but typically takes several hours, he noted.

Still, aside from COVID-19 scenarios, a portable unit would be useful in the ICU for patients with stroke or other suspected brain injury, who are difficult to transport for imaging given the tubes and equipment they are hooked up to, Seifi told 麻豆传媒.

The study included 50 patients in the neuroscience or COVID-19 ICUs at Yale New Haven Hospital from October 30, 2019, to May 20, 2020.

Eligibility centered on neurological injury as determined by a clinical radiographic reading for patients in the neuro ICU or any neurologic alteration on clinical exam if in the COVID unit. Among the patients, nine presented with ischemic stroke, 12 with hemorrhagic stroke, two with subarachnoid hemorrhage, three with traumatic brain injury, four with brain tumor, and 20 with COVID-19 infection with altered mental status.

Participants couldn't have contraindications for conventional MRI or a body size that wouldn't fit in the scanner's 30-cm vertical opening. Other exclusion criteria were cardiac pacemakers or defibrillators, IV medication pumps, insulin pumps, deep brain stimulators, vagus nerve stimulators, cochlear implants, pregnancy, ongoing extracorporeal membrane oxygenation treatment, and cardiorespiratory instability.

MRI examination took an average of 35 minutes and 40 seconds. Sequences obtained were:

• Diagnostic-grade T1-weighted for 37
• T2-weighted for 48
• T2 fluid-attenuated inversion recovery for 45
• Diffusion-weighted for 32

"The main limitations of this study are the single-center design and the limited number of patients imaged," the researchers noted. "Prospective multicenter studies in which [point-of-care] MRI diagnostic results are compared with conventional computed tomography or MRI results for discrete pathologies are necessary for further validation."

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