A Closer Look at the New Appropriate Use Criteria for Brain PET: An Interview with Phillip Kuo, MD, Part 2

“I like to say that amyloid (PET) is necessary for the diagnosis of Alzheimer’s disease but not sufficient,” noted Phillip Kuo, M.D., during a recent interview to discuss the recently released appropriate use criteria for amyloid and tau positron emission tomography (PET) in patients with mild cognitive impairment (MCI).

Dr. Kuo offered insights on the use of amyloid and tau PET in three cases involving a man in his 80s who veered back and forth in testing between early amnestic mild cognitive impairment (MCI) and normal results over the course of a year; a 74-year-old with MCI, suspected vascular contribution and a history of stroke; and a 60-year-old patient who had recent progression from early Alzheimer’s disease to frank dementia.

As Dr. Kuo conveyed with these cases in the interview, these patients had very different stages of disease, yet their amyloid PET scans appeared to be similar.

“The amyloid is the first half, but it doesn't give us the entire second half, like those cases I showed you, (with) that insight into that neuropathology. You can be amyloid PET positive and still not have your symptoms be due to Alzheimer's disease. … The tau PET is more specific that your symptoms are really due to Alzheimer's disease,” explained Dr. Kuo, a professor and division chief of nuclear medicine in the Department of Diagnostic Radiology at the City of Hope Cancer Center in Duarte, Calif.

(Editor’s note: The images and cases discussed in the video are courtesy of Gene Alexander, M.D., the Banner Alzheimer’s Institute in Tucson, Az., and the Radiological Society of North America (RSNA).)

While emphasizing that brain PET imaging is among a variety of factors that clinicians use in determining whether anti-amyloid antibody therapy is appropriate for patients, Dr. Kuo emphasized that the combination of amyloid PET and tau PET offers a complementary diagnostic picture in cases of uncertain presentations.

“ … To get that complete picture, we need to know the biomarkers. We can get that non-invasively with both amyloid PET now as well as tau (PET). Hopefully, these appropriate use criteria will make help clinicians out there to really make sure that we bring value to patient care using these non-invasive, very important and powerful tools for assessing biomarker positivity and also biomarker spatial distribution in the brain,” added Dr. Kuo.

(Editor’s note: For related content, see “A Closer Look at the New Appropriate Use Criteria for Brain PET: An Interview with Phillip Kuo, MD, Part 1,” “SNMMI Issues New Appropriate Use Criteria for Amyloid PET and Tau PET Imaging” and “FDA Grants Fast Track Designation to Emerging Tau PET Imaging Agent.”)

For more insights from Dr. Kuo, watch the video below.