Portable, Bedside MRI Effective in Identifying Intracranial Hemorrhage

Fran Lowry

September 03, 2021

A portable, low-field MRI device is effective in helping to identify intracranial hemorrhage (ICH) right at a patient's bedside, new research suggests.

Such a device can provide crucial, lifesaving information — especially in remote areas where access to traditional MRIs or other sophisticated brain imaging is not readily available, researchers note.

Study results showed that the low-imaging portable MRI (pMRI) held its own when compared with traditional MRI. It not only showed high accuracy in diagnosing ICH, but could also differentiate between ICH and non-ICH cases in critically ill patients.

"Timely neuroimaging is a critical step in the diagnostic workup of patients presenting with suspected acute brain injury such as stroke," principal investigator Kevin Sheth, MD, professor of neurology and neurosurgery at Yale School of Medicine, New Haven, Connecticut, told Medscape Medical News.

Clinicians faced with a patient showing symptoms of stroke must determine if these symptoms are caused by a clot that can be treated with blood thinners or if they are caused by bleeding in the brain, which may require surgery, Sheth noted.

"Intracerebral hemorrhage is a contraindication for thrombolytic therapy, so ruling out the presence of blood is one of the main decision steps in acute stroke care. There is no question this device can help save lives in resource-limited settings, such as rural hospitals or developing countries," he said.

The findings were published online August 25 in Nature Communications.

High Sensitivity, Specificity

The low magnetic field is what makes the device so portable, said Sheth.

"Literally, you can take the device, put it on wheels, wheel it around, and in a clinical environment where you might have oxygen tanks, ventilators, having credit cards in your wallet, none of that is going to be a problem like it would with a normal magnet," he said.

In the study, investigators compared results of 144 scans of patients with brain injuries that were obtained with the portable point-of-care MRI system (called Swoop™ and manufactured by Hyperfine Research Inc) with conventional neuroimaging scans done at New Haven Hospital between July 2018 and November 2020.

As reported by Medscape Medical News, preliminary findings from the researchers were presented last year at the annual International Stroke Conference.

The newly published results showed that exams were classified as positive or negative for ICH in 130 of the 144 cases, for an overall positivity rate of 90.3% (95% CI, 0.72 - 0.86).

In addition, intracerebral hemorrhage was detected in 45 of 56 cases, for a sensitivity rate of 80.4% (95% CI, 0.68 to 0.90), and blood-negative cases were identified in 85 of 88 cases, for a 96.6% specificity rate (95% CI, 0.90 to 0.99).

Primary ICH in a supratentorial location, which is the most common presentation of ICH, was correctly identified in 44 of 50 cases, for a sensitivity rate of 88% (95% CI, 0.76 to 0.95). 

Additionally, total imaging time for the pMRI exam was 30 minutes vs 67 minutes for a conventional MRI exam. 

A Paradigm Shift?

Portable low-magnetic imaging changes the paradigm, said Sheth.

"It can be on wheels, it's easy to use, it self-generates, [provides] useful images, and because it's low field, it's a fraction of the cost," he said.

Sheth noted that a conventional MRI costs more than $1 million, while a portable device such as the one used in the study "might be $50,000 or $100,000."

He added that this type of device would be especially useful in rural areas of the country and to local hospitals.

"There are a number of brain conditions, stroke, head trauma, brain infection, brain tumors, the operating room, all kinds of neurological conditions" where portable MRI could be useful, said Sheth.

The study was funded by the American Heart Association and the National Institutes of Health, and by a grant from Hyperfine Research. Sheth reports no relevant financial relationships. Disclosures for the other authors are fully listed in the original article.

Nat Commun. Published online August 25, 2021. Full text

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