US Patent Issued for Software That Could Make MRI Scans Safer

Subtle Medical announced the granting of a U.S. patent for its radiology software that uses artificial intelligence to improve the quality of medical imaging, with the potential to reduce the amount of gadolinium, a contrast agent, needed to one-tenth of its usual dose.

Gadolinium, a heavy metal, is included in contrast agents delivered through intravenous injection, and used in about one in every three magnetic resonance imaging (MRI) scans to improve the visibility of internal tissues, blood vessels, and organs. This contrast agent is often given to people with multiple sclerosis (MS), who undergo these scans to detect areas of active inflammation in the brain.

However, gadolinium can stay in a person’s body for months to years, raising safety and liability concerns — particularly for pediatric patients, people with multiple lifetime scans, and those whose kidneys cannot clear the contrast agent effectively.

The U.S. Food and Drug Administration issued a warning about the contrast agents in 2017, which noted that people with inflammatory conditions may also be “at higher risk for gadolinium retention.”

The patent issued, No. 10,997,716, covers the software invented by Subtle Medical’s co-founders and is based on technology exclusively licensed from Stanford University. 

“This patent recognizes our AI [artificial intelligence] software as a fundamentally new solution that can significantly improve the visualization before and after contrast administration with lower doses of contrast than are currently used,” Enhao Gong, PhD, co-founder and CEO of Subtle Medical, said in a press release.

AI is a branch of computer science focused on building machines that are programmed to think and make decisions like humans. To train the machines, computer scientists use deep learning, a type of machine learning that looks for patterns in algorithms inspired by the workings of the human brain.

Subtle Medical’s vendor-neutral software was built upon an investigational, patented technology called SubtleGAD, which uses deep learning algorithms to enable a 90% dose reduction of gadolinium for contrast-enhanced MRI exams, while keeping image quality high, the company reported.

“Significantly reduced contrast agent dosage can be used to obtain diagnostic information in medical imaging, enabling safer exams for patients worldwide,” Gong said.

The deep learning algorithms are reported to integrate seamlessly with any MRI scanner without requiring workflow changes. When a lower dose of gadolinium is given, SubtleGAD works to preserve image quality for more accurate diagnoses.

“The diagnostic quality seen with low dose images enhanced by SubtleGAD’s state-of-the-art technology has shown to be clinically equivalent to the full-dose images in our research,” said Greg Zaharchuk, MD, PhD, also a company co-founder.

Research showing the feasibility of the newly patented technology was published in 2018. Subtle Medical also received a $1.6 million Small Business Innovation Research (SBIR) Grant to pursue research into SubtleGAD in 2019.

Subtle Medical has two other AI-based technologies, SubtleMR and SubtlePET, both of which are cleared for use in the U.S. and European Union.