WEDNESDAY, Nov. 30 (HealthDay News) -- Photon emission tomography (PET) with amyloid ligand Pittsburgh compound B (PiB-PET) has similar accuracy as PET with fluorodeoxyglucose (FDG-PET) for differentiating Alzheimer's disease (AD) from frontotemporal lobar degeneration (FTLD), according to a study published online Nov. 30 in Neurology.
Gil D. Rabinovici, M.D., from the University of California San Francisco, and colleagues compared the diagnostic performance of PiB-PET and FDG-PET in differentiating between AD and FTLD (62 snd 45 patients, respectively). Using a quantitative threshold derived from 25 controls, two visual raters, blinded to clinical diagnosis, quantitatively classified PiB scans as positive or negative. FDG scans were quantitatively classified based on the region of lowest metabolism relative to controls, and were visually rated as consistent with AD or FTLD.
The investigators found that for AD, PiB visual reads had higher sensitivity than FDG visual reads (between-rater average: 89.5 versus 77.5 percent) and similar specificity (83 versus 84 percent). Quantitative classification of scans revealed higher sensitivity with PiB versus FDG (89 versus 73 percent), and higher specificity with FDG versus PiB (98 versus 83 percent). PiB and FDG had similar areas under the curve on receiver operating characteristic analysis. Interrater agreement, and agreement between visual and quantitative classification was higher for PiB than FDG. In patients with known histology, PiB and FDG had overall classification accuracy (two visual and one quantitative classification per patient) of 97 percent in 12 patients and 87 percent in 10 patients.
"PiB and FDG showed similar accuracy in discriminating AD and FTLD," the authors write.
Several authors disclosed financial ties to the pharmaceutical and health care industries. One author may accrue revenue from patents pertaining to diagnosis and treatment of Alzheimer's disease.
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