The role of FDG PET in the management of dementia patients

Abstract

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Objectives: PET brain imaging with 2–deoxy-2[18 F] fluoro-D-glucose (FDG) has been reported as a potentially useful diagnostic tool for various types of dementia. Results in the literature contend that FDG-PET can contribute unique information for the accurate diagnosis of MCI (mild cognitive impairment) and dementia stricken patients. However, the impact of FDG-PET scanning in the management of these types of patients is unknown. The aim of this work was to determine, based on the assessment of referring physicians, the role of PET in the diagnosis and clinical management of dementia patients. Methods: Between March 2004 and August 2005, FDG-PET scans were performed on 96 patients with suspected dementia or MCI. Standardized questionnaires were then faxed to all referring physicians (45) asking them to report on whether/how results of the FDG-PET scan influenced patient management. A cover letter explaining the scope and purpose of the study was attached to each survey. Results: Surveys were completed and returned by 41 physicians. The response rate was 73/96 (76%). Initial surveys were sent 3 months after the date of the scan. Additional follow-up surveys were returned on 51/73 cases within six months to one year i.e. 69.9% (95% CI=58.6-79.2%). Survey results indicated that the PET scan information changed the initial diagnosis of 19/73 patients i.e. 26% (95% Confidence Interval (CI)=17.3-37.1%) and distinguished Alzheimer’s from frontoparietal dementia, SND (Striatonigral degeneration), Lewy Body Dementia, Huntington’s Chorea and age related dementia. In addition, the diagnosis based on FDG-PET scan changed the disease management in 20/73 patients i.e. 27.4% (95% CI=18.5-38.6%) leading to the initiation of anticholinergic drug therapy in 14 of these 20 patients. The PET findings were found to be in agreement with the initial diagnosis made by the referring physicians in 53/73 i.e. 72.6% (95% CI=61.4-81.5%) of the patients. Conclusions: This survey-based study of referring physicians indicates that the results of FDG-PET brain scanning can be a powerful tool for the differential diagnosis (26%) and management (27.4%) of dementia and MCI patients.