Abstract
1528
Objectives: Cerebral Lewy body often coexists with beta amyloid (Aß), which may explain pathogenesis of variable presentations of dementia with Lewy bodies (DLB). Although DLB with Aß tends to show progressive cortical dementia begging with memory disturbance, clinical characteristics has not yet established due to technical difficulties to diagnose ongoing cerebral pathology. The study objective was to investigate basic characteristics of DLB under the precise diagnosis of cerebral Aß pathology using F-18 flutemetamol (FMM) PET.
Methods: Study population included 34 patients with clinically diagnosed DLB. Clinical diagnosis was made based on all available information except for the results of the PET scan. All underwent PET acquisition for 30 minutes in a list-mode, after FMM injection at rest. Average injected dose was 193.6 ± 9.1 MBq and uptake-period was 90 minutes. The results of FMM PET scans were discussed in a group of researchers including referring physicians and diagnostic radiologists reviewing all the available information to classify the DLB patients into two groups consisting with either "Positive" or "Negative" for beta-amyloid pathology. In the present study, patients age, gender, and Mini-Mental State Examination (MMSE) were compared between the two groups. In subgroups of patients, the results of I-123 metaiodobenzylguanidine (n = 22), and I-123 Ioflupane (n = 21) scans were also compared to investigate cardiac sympathetic denervation and dopamine transporter (DAT) dysfunction, respectively.
Results: FMM PET disclosed positive Aß in 19 (out of 34, 56 %) DLB patients. There was no significant difference between DLB patients with vs. without Aß in age, gender, MMSE or in DAT dysfunction. Among the characteristics investigated, only cardiac denervation was more frequently observed in DLB patients in Aß ngetative group (p < 0.05).
Conclusions: Concomitant cerebral Aß pathology was common in DLB patients showing positive FMM PET scan in more than half of the investigated population. The Aß pathology was not significantly associated with differences in the clinical characteristics investigated except for the cardiac denervation. However, further investigation will be required for more detail characterization.