Relationship between cerebral blood flow reduction patterns on scintigraphy and nonmotor symptoms in new-onset Lewy body disease.

BACKGROUND: This study aimed to investigate the relationship between patterns of reduced cerebral blood flow (CBF) evaluated by means of 123I-N-isopropyl-p-iodoamphetamine ([123I]IMP) scintigraphy and nonmotor symptoms in new-onset Lewy body disease (Parkinson's disease and dementia with Lewy bodies [DLB]). MATERIAL AND METHODS: Twenty-four patients diagnosed with new-onset Parkinson's disease or DLB underwent [123I]IMP CBF scintigraphy at St. Marianna Medical University Hospital between January 1, 2010, and March 30, 2018. The reductions in CBF in various brain regions were analyzed using the three-dimensional stereotactic surface projection method and were compared to standard database values, yielding extent values (%). The extent values were evaluated in relation to the presence/absence of motor or nonmotor symptoms such as visual hallucinations, auditory hallucinations, delirium, depression, delusions, and dementia. RESULTS: The extent value was 100% in the angular, supramarginal, and lingual gyri; 95% in the orbital gyri; and 92.6% in the fusiform gyri. The extent value in patients without hallucinations and those with visual hallucinations was 41.2% and 54.3%, respectively, in the frontal lobe (p = 0.02) and 33.3% and 51.0%, respectively, in the medial prefrontal gyri (p = 0.02). Age-adjusted multivariate analysis showed that extent values in the frontal lobe were associated with visual hallucinations (odds ratio: 1.09, 95% confidence interval 1.00-1.18, p = 0.04). CONCLUSIONS: The above results show that the CBF is reduced in several areas of the cerebral cortex and suggest an association between reduced blood flow in the frontal lobe and the appearance of visual hallucinations in patients with new-onset DLB.

Neuroanatomical correlates of low body weight in Alzheimer's disease: a PET study.

Weight loss is a common problem in patients with Alzheimer's disease (AD) and this might be associated with an increased risk for mortality. Recent evidences have suggested that certain brain dysfunctions may result in impaired nutritional status in AD patients. However, the mechanism of body weight loss in AD remains enigmatic. To investigate a possible association between low body weight and regional brain dysfunction, the authors conducted the correlational analysis of body mass index (BMI) with regional brain glucose metabolism using positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG). Twenty-seven patients with probable AD were divided into two groups: the low BMI group and the normal BMI group. Regional brain glucose metabolic ratios were calculated using the cerebellar hemisphere as a reference region. Comparisons were made of regional brain metabolic ratios between the low BMI group and the normal BMI group. Correlations of the glucose metabolic ratio with BMI were also assessed in all patients with AD. In the comparison between the two groups, glucose metabolic ratio in the anterior cingulate cortex (ACC) was significantly lower in the low BMI group, whereas no significant differences were found in all the other brain regions. Furthermore, regional glucose metabolism in the ACC had a significant and positive correlation with BMI (r=.450, P=.018). After adjustment for age, gender and disease duration, regional glucose metabolism in the ACC was independently associated with BMI. Our findings suggest that the ACC may be preferentially involved in the regulation of nutritional status in AD patients, and provides a new insight into developing strategies for prevention and treatment of undernutritional demented patients.