An Alzheimer’s PET project is coming into sharper focus. The usefulness of positron emission tomography (PET) images in conceptualizing brain plaques for the condition has piqued so much clinical interest, in fact, that the Society of Nuclear Medicine and Molecular Imaging (SNMMI) and the Alzheimer’s Association have released an initial set of criteria for those who wish to treat by PET.
"Our primary goal is to provide healthcare practitioners with the information and options available to provide patients with the best possible diagnosis and care in a cost-effective manner," said Maria Carrillo, PhD, Alzheimer's Association vice president of Medical and Scientific Relations, in a prepared statement.
The recommendations — published Jan. 28 in both Alzheimer's & Dementia: The Journal of the Alzheimer's Association and the Journal of Nuclear Medicine — officially originate from the Amyloid Imaging Taskforce (AIT), an assembly of imaging experts formed by SNMMI and the Alzheimer’s Association to review scientific literature in search of PET best practices. The ultimate conclusion for the AIT was that amyloid imaging could indeed prove helpful when attempting to diagnose patients with cognitive impairment if reviewed in conjunction with other clinical information and if standard protocols were followed comprehensively by trained staff.
For a patient to qualify for amyloid imaging via PET, the AIT recommends the following characteristics be present:
- Those who complain of persistent or progressive unexplained memory problems or confusion and who demonstrate impairments using standard tests of cognition and memory.
- Individuals meeting tests for possible Alzheimer's, but who are unusual in their clinical presentation.
- Individuals with progressive dementia and atypically early age of onset (before age 65).
Conversely, the taskforce insisted the imaging not be used on:
- Those who are age 65 or older and meet standard definitions and tests for Alzheimer's, since a positive PET scan would provide little added value.
- Asymptomatic people or those with a cognitive complaint but no clinical confirmation of impairment.
The imaging is also advised against by the AIT when:
- It is applied as a means of determining the severity of dementia.
- Requested solely based on a family history of dementia or presence of other risk factors for Alzheimer's, such as the ApoE-e4 gene.
- It is a meant to be used as a substitute for genetic testing for mutations that cause Alzheimer's.
- It is a meant to be used for non-medical reasons, such as insurance, legal or employment decisions.
Additionally, the AIT insists that physicians and other providers take the following steps to access if a particular case warrants PET:
- Evaluation by a dementia expert to assess the need for diagnostic testing, possibly to include amyloid PET if the AUC are met.
- Referral to a qualified provider of amyloid PET services.
- Performance, interpretation and reporting of the amyloid PET scan according to established standards.
- Incorporation of the PET result into the clinical assessment process.
- Disclosure of the PET result by the clinician to the patient and caregivers, along with discussion of the result and its management consequences.
"As amyloid imaging becomes more prevalent in clinical settings, medical professionals must understand how to appropriately utilize the test," said Frederic H. Fahey, DSc, SNMMI president, in a news release. "Neurology and dementia experts should order the test only when appropriately indicated, and nuclear medicine and molecular imaging professionals must ensure they have been adequately trained to interpret the results of the scan. Working together, we hope that the information garnered from amyloid PET imaging will aid in diagnosis and play a pivotal role in the development of new treatments for Alzheimer's."
Currently, amyloid imaging is not covered by insurance. As scan costs vary from location to location, no general price-marker has been set, although the AIT cites some PET racking up charges of $1,000 to $3,000 or more.
Despite the steep out-of-pocket costs “the AIT concluded that the proven sensitivity and specificity of the new radiopharmaceuticals for brain amyloid and the known association between brain beta amyloid deposition and Alzheimer's suggest these new radiopharmaceuticals could potentially be helpful in the workup and diagnosis of patients with cognitive impairment.”