Patients suffering from ischemic or hemorrhagic stroke could soon undergo brain MRIs at their bedside instead of braving crowded hallways and tight elevators, traveling to an MRI scanner located in a different hospital wing.
Currently, in order to obtain clinical-quality images, hospital staff must transport these critically ill patients to a room that houses a large, high-field MRI scanner. Not only is it a safety risk to move a stroke patient, but these exams are expensive.
In a presentation of new research next week during the International Stroke Conference, Kevin Sheth, M.D., chief physician in the Yale School of Medicine and Yale New Haven Hospital division of neurocritical care and emergency neurology, will discuss the early results of the clinical performance of portable, low-field MRI.
“MRI is one of the most helpful and safest diagnostic technologies, but because of the high field and everything emanating from that high field, you have to take that safe technology and put it in the bunker of the hospital away from the patient where it’s difficult to access,” he told Diagnostic Imaging in an interview. “Low field is important because, if you can obtain images of the brain that are clinically useful, you can switch from high field, and all the safety concerns go away. Instead of taking the patient to the MRI, you can bring the MRI to the patient.”
In an effort to test the technology’s efficacy, Sheth’s team conducted bedside MRI with 85 stroke patients within seven days of symptom onset, using the 510(k)-pending portable machine developed by the manufacturer Hyperfine. The patients ranged in age from 18 to 96, and 46 percent were women. Of the participants, 46 percent experienced ischemic stroke, 34 percent had intracerebral hemorrhage, and 20 percent suffered subarachnoid hemorrhage. Exams lasted, on average, 30 minutes, and only 11 patients couldn’t complete the exam – five because they couldn’t fit inside the machine’s 30-centimeter opening, and six due to claustrophobia.
Potential Benefits and Challenges
Alongside the convenience of wheeling an MRI machine into a patient’s room, there are several other possible benefits to using the low-field machine, Sheth said.
For example, the portable MRI, which is roughly half the size of a portable CT scanner, uses a 64mT magnet, compared to a 1.5T or 3T magnet used in conventional MRIs. Such a substantial difference removes many of the safety issues associated with the modality.
“It’s really a fraction of the strength. I’ve scanned myself, and we’ve had a lot of volunteers. You can take in your wallet, your keys, and your glasses,” Sheth said. “But, we’ve also had a lot of brain-injured individuals in the ICU setting – those who have been intubated or not intubated. Others have been on ventilators or had oxygen tanks in the room. It’s been safe in every case.”