Comparative Study on Multimodal Imaging Applications in Dementia with Lewy Bodies: From Imaging Features to Clinical Practice Implications.

Objective: To explore the value of multimodal molecular imaging in diagnosing and differentiating dementia with Lewy bodies (DLB). Methods: A retrospective analysis was conducted on clinical data and multimodal molecular imaging of 40 probable DLB patients treated at Peking Union Medical College Hospital (August 2017-December 2024). All 40 had 18F-FDG PET/CT; 15 had 131I-MIBG imaging; 11 had 18F-FP-CIT PET/CT. A total of 12 patients with poor cognition or atypical 18F-FDG PET/CT underwent 18F-AV45 PET/CT (2 also had 18F-PM-PBB3 imaging). A sex- and age-matched control group (cognitively normal, same-period health checkup 18F-FDG PET/CT) was included. 18F-FDG PET/CT images were visually and semi-quantitatively analyzed (ROI, SPM). 18F-AV45 PET/CT was assessed both visually and semi-quantitatively; 131I-MIBG imaging and 18F-FP-CIT PET/CT were visually evaluated. Results: The 40 DLB patients (29 males, 11 females; mean age 72 years) had distinct initial symptoms: 8 (20%) presented with cognitive decline as the first symptom, 23 (57.5%) with parkinsonian symptoms as the first symptom, and 9 (22.5%) with both symptoms occurring simultaneously. Mean intervals: 16.25 months from initial cognitive decline to parkinsonian symptoms, and 24.43 months from initial parkinsonian symptoms to cognitive decline. All had parkinsonian symptoms and cognitive impairment; 38 (95%) had visual hallucinations; and 26 (65%) had REM sleep behavior disorder. 18F-FDG PET/CT: 30(75%) showed typical occipital hypometabolism and posterior cingulate island sign; 10 (25%) had atypical findings. 131I-MIBG (15/15, 100%): cardiac sympathetic denervation. 18F-FP-CIT (10/11, 90.9%): basal ganglia dopaminergic damage. 18F-AV45 (9/12, 81.8%): positive. Semi-quantitative 18F-FDG analysis revealed parietal, occipital, and lateral temporal hypometabolism in DLB (left more severe than right). Conclusions: Dementia with Lewy bodies (DLB) presents with pre-onset parkinsonism and cognitive impairment, plus high rates of visual hallucinations and sleep disorders. Key imaging features-occipital hypometabolism/island sign on 18F-FDG PET/CT, cardiac sympathetic denervation on 131I-MIBG, and basal ganglia dopaminergic damage on 18F-FP-CIT-aid DLB diagnosis. 18F-AV45 PET/CT detects Aβ pathology in severely cognitively impaired patients, suggesting these DLB patients may have underlying AD pathology beyond DLB.