London team uses MRI in OR for quick feedback

LONDON, Ont. – The use of a portable MRI during a complex pituitary tumour procedure is being hailed as a “game-changer” by the London Health Sciences Centre neurosurgeon who led the operation. A Hyperfine Swoop portable brain MRI was used during a procedure to remove a patient’s pituitary tumour at University Hospital in October, enabling the surgical team to see the intricate area of the brain in real time, said LHSC neurosurgeon Dr. Neil Duggal.

The Swoop is a portable, low-field MR – designed for head exams – that can be wheeled into the operating room. It has a field strength of just 0.064T, compared with the 1.5T field strength of a conventional scanner, and it’s much smaller.

That compact size allows it to easily fit into the OR, and the low-intensity of the magnetic field means surgeons can still use their regular metal instruments – something that would be impossible with a full-strength magnetic scanner.

The pituitary gland is a pea-sized gland attached to the brain that produces and releases hormones controlling many bodily functions, including growth, metabolism, blood pressure and reproduction.

“We were able to use this (MRI) for a pituitary tumour to know if we had completely removed the tumour,” Dr. Duggal told the London Free Press.

Loss of peripheral vision, hemorrhages and hydrocephalus, which can lead to headaches, vomiting, seizures, and mobility and cognitive issues, are among symptoms of pituitary tumours, he said.

The surgery to remove the tumour was performed endoscopically through the nose and is complex because the carotid arteries – which supply blood to the brain – and optic nerves that transmit information from the eyes to the brain lie close to the tumour, Duggal said.

A slip-up could be “disastrous,” he said. Injury to the carotid arteries “could lead to a catastrophic hemorrhage, stroke or death,” while damage to the optic nerves could cause tunnel vision or blindness.

The value of the portable MRI is that, rather than moving a patient elsewhere in the hospital for imaging, which can take hours in some cases, the MRI is brought to the patient’s bedside, Duggal said.

With the device in the operating room, the surgical team can receive “immediate feedback,” he said, adding that leftover tumour residue could lead to regrowth and potentially require another operation.

Duggal said the portable MRI enabled the team to spot tumour residue during the operation.

“Getting that immediate feedback . . . allowed us to go right back into that one spot where we saw residual tumour and to tackle it and remove it,” Duggal said. “I think that’s invaluable.”

The procedure was successful for Dave Evans, the patient who underwent what LHSC says was the first pituitary tumour surgery in the world to use the Hyperfine Swoop portable MRI.

Evans, who lives in Owen Sound, said he began experiencing symptoms in 2020 but did not know the cause at the time.