Portable MRI For Neuroimaging In ICU Patients A Game-Changer During Pandemic

Having access to portable magnetic resonance imaging (MRI) for neuroimaging of patients with COVID-19 in the intensive-care unit (ICU) has been a game-changer during the pandemic, say neurosurgeons from New York.

"This technology leapfrogs" over many of the problems encountered with conventional MRI in ICU patients, Dr. Michael Schulder, vice chair of neurosurgery at North Shore University Hospital in Manhasset and Long Island Jewish Medical Center in New Hyde Park, told Reuters Health by phone.

"The idea that you could just bring a small MRI to any patient bed, anywhere in the hospital, is kind of mind blowing," said Dr. Schulder.

Neuroimaging is often required in ICU patients to rule out a variety of intracranial problems. Computed tomography (CT) may be available in the ICU itself, but MRI is more sensitive for many conditions that affect the brain. However, transporting patients who are on ventilators and other life-sustaining devices is labor-intensive and puts the patient at risk for adverse events.

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In a report in Critical Care Explorations, Dr. Schulder and colleagues describe their experience imaging 19 ICU patients with COVID-19 at the bedside using a portable, self-shielding, 0.064-T MRI unit (Hyperfine).

Indications for neuroimaging were unexplained encephalopathy or coma, seizures, focal neurologic deficit or abnormal head CT. They obtained a total of 20 MRI scans.

The bedside MRI was successfully used in seven ICUs on six floors of the hospital, each with a unique floor plan that required individual attention. Obtaining each image took 39 minutes and the average bedside time from start to finish was 90 minutes per patient.

The team successfully scanned up to four patients per day. "This was the practical limit during the peak pandemic period due to limited personnel available at our institution," the researchers write.

No patients or staff suffered any adverse events. Throughout the imaging process, patients remained in the ICU connected to all necessary lines and mechanical ventilation. Clinicians could request, order and immediately review images using the hospital's electronic medical record (EMR) and picture archiving and communications systems (PACS). Critical care physicians and nurses continued with routine care during scanning.

The study team developed a protocol for safe use of portable MRI in the ICU, "and once we got the routine down, things flowed very smoothly and we were able to acquire scans on demand," Dr. Schulder told Reuters Health.

Imaging quality was adequate in nearly all of the acquisitions in detecting the presence or absence of brain abnormalities.

Abnormal findings on MRI were found in 12 patients (63%), most commonly fluid attenuated inversion recovery (FLAIR) signal changes, but also hemorrhage and restricted diffusion.

Imaging findings led to changes in clinical management in five patients. For example, "we saw patients who had evidence of a stroke without hemorrhage, and we were able to start them on anticoagulation and that was a pretty profound intervention for those people," Dr. Schulder said.

Even getting a negative MRI in patients can provide important information, he said. "If someone is not awakening from sedation for several days, for instance, there's a big difference from getting an MRI that shows a big stroke or one that's in essence normal because it will change your approach to the patient," he explained.

Portable MRI also has cost-saving benefits. "Besides the benefit of significantly lower costs of the scanner, there are healthcare costs associated with transporting critically ill patients on isolation precautions to and from the MRI scanner. These costs will vary among various institutions, and this is a topic for future studies," the authors note in their article.

Limitations of the study include the small sample size and the learning curve associated with the early use of new technology, particularly during a pandemic.

"Throughout the study, the strategy and logistics to perform portable MRI (such as patient-positioning, unique ICU considerations, and device transport) were continually improved," the authors note.

The study also lacked comparison with current standard-of-care imaging devices, such as portable CT and conventional MRI, limiting "the conclusions about its clinical utility but provides promising preliminary data about the feasibility, safety, and expected utility in a clinical setting."

Hyperfine, of Guilford, Connecticut, provided the portable MRI system used in this study. None of the authors have any commercial interest in Hyperfine. The senior engineers of Hyperfine reviewed the article for the accuracy of technical descriptions of the device.

—Megan Brooks

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