From eye care to cancer care: Expanding role of OCT imaging

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Since its inception in 1996, optical coherence tomography (OCT) has become a staple in eye care imaging technology. It has transformed how clinicians are able to diagnose and treat blinding diseases such as macular degeneration, glaucoma, and diabetic retinopathy. Millions of OCT scans are performed yearly, and recently, the technology has started to see usage outside of eye care.

Providers in cardiology, neurology, oncology, and other fields have also found useful ways to integrate OCT imaging into their practices, underscoring a growing trend of cross-disciplinary innovation. Perimeter Medical Imaging AI is another entity aiming to transform the traditional usage of OCT. A medical technology company formed in Toronto, Ontario, Canada, Perimeter has been leveraging the technology to improve breast cancer surgeries and reduce the number of patients requiring repeat surgery.

Andrew Berkeley, co-founder and chief innovation officer at Perimeter, sat down with Ophthalmology Times to discuss how the company is leveraging OCT technology in the operating room during breast-conserving surgeries, also known as lumpectomies.

One of the challenges in breast-conserving surgeries is intraoperative margin assessment, in which surgeons take a specimen from the patient to be analyzed by pathology for cancer cells. In that analysis, if cancer cells are found at the end of the removed tissue and are present in the margin, this is called a positive margin. Positive margins typically result in the patient being called back for a follow-up surgery. Traditionally, this process can take between 2 days to 2 weeks to get information back, according to Berkeley.

“The patient is at home, waiting nervously to know that [they] have a successful surgery, and [they] have no more cancer,” said Berkeley, which can cause great amounts of stress.

Berkeley said that during lumpectomies, around 20% of patients require a re-excision, a number the company hopes to reduce entirely with its Perimeter B-Series OCT device.

“Our device sits in the operating room. The specimen comes from the patient. We place it on [the OCT] platform. And then we carefully position each of the 6 sides of the specimen, and we take an OCT image,” said Berkeley. “What happens then is a trained reader can then quickly look through the images and interpret whether or not there are abnormalities at the surface or down to 1-2 millimeters. And at that point, the surgeon can then make a decision; Do I close the patient, or do I want to take more action based on what I see in these images? Without OCT, they literally are handing the specimen off to pathology to wait.”

This reduction in waiting time, and the ability to see and act, allows for surgeons to more effectively address residual cancer in the operating room, said Berkeley.

“We're giving them a view inside of that margin in real-time, with the hope that they'll be able to find if there is a concerning area, and then they can take action based on that while the patient is on the table,” he said.

Berkeley stressed that the device in no way aims to replace pathology but is a tool that can help.

“We actually feel that our images can be very beneficial to pathology,” he added. “If the pathologist on receipt of the specimen could look at the OCT images, it might allow them to prioritize certain regions for sampling. This could potentially improve the accuracy of where they sample and also introduce some efficiencies into the pathology process.”

The company has also introduced an AI tool to the OCT device to reduce the learning curve. The ImgAssist AI 2.0, a proprietary tool from Perimeter, “separates each image into a patch, [does] an analysis on the patch, and [gives] it a confidence level.” Outside of this, the AI also allows for faster imaging according to Berkeley. “What we've been able to do is we just take one image and then we have a synthetic noise that comes in and we apply that to the image. So it makes the images look better, and it also reduces the scan time. That’s important because we're in the operating room. So, there are other technologies that we’re developing that could be used in the world of OCT.”

Recently, Perimeter conducted a clinical trial of the Perimeter B-Series OCT with ImgAssist AI 2.0 that resulted in a statistically significant reduction in patients with residual cancer during surgery.

This prospective, multicenter, randomized, clinical trial enrolled 206 patients with breast cancer who are undergoing lumpectomy for the treatment of Stage 0-III invasive ductal carcinoma and/or ductal carcinoma in situ. Patients were evaluated to measure the effectiveness of the combined B-Series OCT imaging system with ImgAssist AI 2.0 compared with lumpectomy current standard methods including palpation, specimen radiograph, intraoperative pathology, and ultrasound in addressing positive margins.¹

According to the results,¹ the B-Series OCT with ImgAssist AI 2.0 enabled surgeons to more effectively address residual cancer at the surgical margin during surgery as compared with current standard methods.

“The promise of B-Series OCT with ImgAssist AI 2.0 is greater peace of mind. Both for the surgeon who – no matter how skilled – currently faces nearly 1-in-5 odds of needing to perform repeat surgery due to positive margins; and for their patient, who under the current paradigm, typically has to wait (and worry) for up to seven days for their surgeon to receive a post-operative pathology report which will determine whether they will have to go through the emotional and physical trauma of a second surgery due to cancer left behind,” Adrian Mendes, Perimeter’s CEO, commented in a press release.¹

Berkeley said the company plans to submit this data to the FDA and work with the organization with the hope of approval for the B-Series OCT with ImgAssist AI 2.0.

“We will submit and we will work with the FDA on making sure that we get the technology through the approval process and to market […] AI is changing rapidly, not just the models that we use, but the amount of data that we will be putting in. So we will continue to work with the FDA on how we can improve our technology.”

Perimeter anticipates that additional analyses, including secondary endpoints and additional reporting from the pivotal trial during lumpectomy, will be presented at an upcoming, unnamed, medical conference.

References:

1. Perimeter B-Series OCT with ImgAssist AI 2.0 demonstrates super-superiority compared to standard-of-care in pivotal clinical trial. Press release. Perimeter. Released November 20, 2024. Accessed November 21, 2024. https://ir.perimetermed.com/news-events/press-releases/detail/160/perimeter-b-series-oct-with-imgassist-ai-2-0-demonstrates?_gl=1*vw0sdx*_gcl_au*ODIzMDI0OTQ4LjE3MzIxOTk4NTY.