Case of the MonthOctober 2004
PET for Early Diagnosis of Alzheimer's
The patient is a 60-year-old male who has complained of memory loss, and his family noted that he was apathetic and at times socially inappropriate for the last twelve months. He has difficulty finding words and has gotten lost while driving. Neurological examination revealed a Mini Mental Status Examination score of 27/30. An MRI of the brain showed diffuse cerebral atrophy more prominent in the bilateral frontal region. Clinical evaluation could not differentiate between early Alzheimers Disease and Frontotemporal Dementia. An FDG PET study was requested to clarify the diagnosis.
The FDG PET brain study demonstrated bilateral symmetric decreased FDG uptake in parietal and temporal lobes (Figure 1). This is a typical pattern for Alzheimers Disease (AD).
Figure 1. Coronal view.
Figure 2. Transaxial view.
Figure 3. Saggital view.
How Did PET Help?
The FDG PET brain scan helped to confirm the diagnosis of early Alzheimers Disease. PET provided the patient and clinician with important information for assessing possible treatment options and planning for the future.
Recent studies have highlighted the value of PET in Alzheimers Disease as a diagnostic tool. It is also a prognostic tool used to identify early changes associated with Alzheimers, in contrast to other neurodegenerative dementias. Early detection of AD will allow physicians to employ existing and new therapeutic options in a timely fashion for the patients maximum benefit (1).
In recognition of the important role that PET can play in the diag- nosis and treatment of Alzheimers Disease, on September 15, 2004, the Centers for Medicare and Medicaid (CMS) approved coverage of FDG PET scans for Alzheimers Disease under conditions in which the diagnosis remains uncertain.
(1) Silverman, Daniel H.S., M.D., Ph.D., Brain 18FFDG PET in the Diagnosis of Neurodegen- erative Dementias: Comparison with Perfusion SPECT and with Clinical Evaluations Lacking Nuclear Imaging, Journal of Nuclear Medicine, Vol. 45, No. 4, April 2004, pp. 594-607.
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