The aim was to evaluate the diagnostic utility of beta-amyloid positron emission tomography (PET) in elderly patients with cognitive impairment in the clinical setting. Five subjects underwent beta-amyloid PET imaging to explore the cerebral beta-amyloid deposition. The two male patients with minor neurocognitive disorder due to Alzheimer's disease, who displayed similar degree of cognitive impairment and medial temporal atrophy but different in apolipoprotein E4 status, both showed negative for beta-amyloid PET. On the other hand, a female major neurocognitive disorder due to probable Alzheimer's disease patient was tested positive for beta-amyloid PET, with increased beta-amyloid density in frontal and parietal lobes. Beta-amyloid PET was also used for the differential diagnosis of neurocognitive disorder from other psychiatric disorders in two elderly patients. The results were negative but assisted the diagnositic confirmation. A female patient was determined to be a case of late-onset schizophrenia and a male patient was determined as delirium due to minor traumatic brain injury, persistent. Beta-amyloid PET imaging was able to demonstrate cerebral beta-amyloid deposition in major neurocognitive disorder due to probable Alzheimer's disease in visual scale. However, further studies are needed for its clinical utility in the minor neurocognitive disorders. Moreover, beta-amyloid PET imaging may provide additional information in diagnosing primary psychiatric disorders with new onset in the old age.
Late Onset Disorders ; Aged* ; Alzheimer Disease ; Amyloid beta-Peptides ; Apolipoprotein E4 ; Atrophy ; Brain Injuries ; Delirium ; Diagnosis, Differential ; Electrons* ; Female ; Hand ; Humans ; Male ; Parietal Lobe ; Positron-Emission Tomography* ; Schizophrenia

Mitochondrial encephalomyopathy with lactic acid and stroke-like episodes (MELAS) is a multisystem mitochondrial disorder that typically presents in childhood. We report a case of MELAS syndrome diagnosed in a 45-year-old man presented with chronic kidney disease before a stroke-like episode. Genetic testing revealed a m.3243A>G point mutation in the mtDNA. The original diagnostic criteria for MELAS required the onset of stroke-like episodes prior to 40 years of age but this case demonstrates that disease onset may delay in certain individuals.
DNA, Mitochondrial ; Genetic Testing ; Humans ; Lactic Acid ; Late Onset Disorders ; MELAS Syndrome* ; Middle Aged ; Mitochondrial Diseases ; Mitochondrial Encephalomyopathies ; Point Mutation ; Renal Insufficiency, Chronic* ; Stroke