Diagnostic Imaging Online
November 1, 2000

Functional imaging can identify Alzheimer's, but not cost-effectively

Functional imaging of the brains of patients with Alzheimer's disease can offer detailed views of the affected portions, but a study suggests that such advanced imaging does not seriously add to the patient's course of treatment.

The research, which did not include PET imaging, raises questions about the utility of new imaging techniques that offer better and earlier glimpses into the chemistry and physiology of Alzheimer's. Those techniques— including PET and functional and structural MR —are featured in the November issue of Diagnostic Imaging.

Decision analysis researchers in the Harvard University radiology department evaluated the cost of treatment for patients at varying stages of Alzheimer's who were scanned with single-photon emission CT or contrast-enhanced MR. The latter averaged a cost of $479,500 per quality-adjusted life year (QALY). SPECT was less cost-effective in many scenarios than the standard diagnostic work-up already given to patients.

By varying the sensitivity of the standard work-up, the severity of patient disease, and the effectiveness of drug treatment, the model came up with QALY costs of $24,680 to $8.6 million for MR and $180,200 to $6 million for SPECT. The research was published in the October issue of Radiology.

"My guess, given the performance characteristics of the existing tests, is that they would have to be almost free to be cost-effective," said Dr. G. Scott Gazelle, coauthor and an associate professor of radiology at Harvard.

Although functional imaging can reveal a great deal about an Alzheimer's-affected brain, such information doesn't give patients or their physicians more options than the handful of drugs now available to treat the disease, and it doesn't improve their mediocre results.

"There are a lot of good tests out there that make pretty pictures," Gazelle said, "but until we have a better way to treat patients or identify them early, they don't offer much more than the standard clinical work-up."

-- By Jane Lowers

For more on Alzheimer's imaging from the DI archives: