Late yesterday afternoon, RadNet Inc., the nation’s largest imaging center chain, performed its first Alzheimer’s Disease test using Eli Lilly’s radioactive tracer Amyvid and PET/CT imaging, confirmed Judith Rose, MD, director of PET/CT and nuclear medicine for RadNet.
The procedure — which was scheduled for 5 p.m. PST at NorCal Imaging in Walnut Creek, Calif. — marked the beginning of one of the largest standardized testing programs so far for Amyvid. Under RadNet’s "Shine a New Light on Dementia" initiative, a total of 10 RadNet centers initially will offer the test and plans are to grow that number to as many as 30 centers across the United States, Rose said.
With a network that includes 237 owned and/or operated outpatient imaging centers, RadNet benefits from having a deep bench of subspecialists that can perform PET/CT neural imaging reads. Rose said that they have six radiologists on the East Coast and six on the West Coast who have gone through the special training recommended by Eli Lilly for detecting the signs of the Alzheimer’s related amyloid plaques in the brain that the Amyvid (Florbetapir F 18) tracer is meant to illuminate.
With multiple available readers, Rose decided to set a protocol above Eli Lilly’s expectations and require two Amyvid-certified RadNet radiologists to arrive at a single consensus after independently interpreting each scan. Amyvid scans are interpreted using a binary visual read methodology. In other words, the test is either positive or negative. There is no in between.
“It is too important to have just a single pair of eyes,” Rose said. In cases where there is not a consensus, she will personally do a third, independent interpretation of the scan and serve at the tie breaker.
The six Amyvid-trained radiologists on the East Coast are all on site. Five out of the six Amyvid-trained radiologists are remote on the West Coast.
Amyvid is somewhat of an ideal test for remote reads because in clinical testing for FDA approval, radiologists read the images without any background clinical information. In its prescribing information, Eli Lilly actually cautions against bringing additional clinical information into the reading as this could bias the radiologist interpreting the scan and has not been tested.
From Rose's perspective, remote reads also allow the interpreting radiologists to gain as much experience as possible on this new and, for the time being, fairly rare test. The FDA just approved Amyvid less than four months ago. After each test is completed, all the reading radiologists across the various sites will get an automatic notification on their workstations and be able to go in and review the images and their colleagues' reads.
“In this case, the remoteness is a very big plus,” Rose said.
Operational challenges in starting to offer Amyvid at multiple locations in multiple states included creating a standardized testing protocol that would work for every site and ensure a consistent patient experience no matter where the imaging was performed. Each step in the process had to be examined and a host of supporting materials created, from writing all new forms to establishing the template for the dictation to training the technologists in a consistent manner.
Each dose of Amyvid is $2,000 — under RadNet’s pricing the majority of the cost of the test — and the tracer has a half-life of only 109.77 minutes. To follow the dosing instructions properly, patients must undergo a 10-minute scan in the narrow time window between 30 and 50 minutes after Amyvid intravenous injection. Get the timing wrong, and the test could be wasted.
Will the effort be worth it? Rose is confident as she sees no less than four potential patient waves.
The first will come with the small number of no-cost procedures each "Shine a New Light on Dementia" participating center will offer their communities in order to educate referral sources and spread the word about the test among patients.
A second wave, Rose said, may come when patients who are able to pay out of pocket for the test learn about it from their doctors. RadNet is requiring a doctor’s referral for all patients to ensure they are appropriate candidates for a test that does involve radiation exposure. Eli Lilly estimates the total radiation exposure from Amyvid administration and subsequent scan on a PET/CT scanner to be 9 mSv.
A third wave is already hitting as drug companies with Alzheimer’s Disease drugs in the pipeline seek