Characterization of cardio-brain dysfunction in Parkinson's disease by PET imaging

The pathological spread of α-synuclein causing multi-organ dysfunction constitutes the primary pathological basis of Parkinson's disease (PD), revealing new directions for clinical management. This study employed 11 C-labeled 2β-carbomethoxy-3β-(4-fluorophenyl) tropane ([ 11 C]CFT) and 18 F-labeled metafluorobenzylguanidine ([ 18 F]MFBG) positron emission tomography (PET) to evaluate brain dopamine transporter activity and cardiac sympathetic nerve function, assessing the utility of combined ([ 11 C]CFT and [ 18 F]MFBG PET imaging for PD diagnosis and differential diagnosis. This study enrolled 22 patients with idiopathic PD and 20 patients with atypical parkinsonian syndromes (APS), all of whom underwent two PET scans. Striatal-to-occipital ratios (SOR) and asymmetry indices (AI) quantified brain dopamine transporter activity on [ 11 C]CFT PET. Mean standard uptake value (SUVmean) quantified cardiac sympathetic function on [ 18 F]MFBG PET to compare intergroup differences. The correlation between cardiac and brain imaging findings was also analyzed. Both groups exhibited significantly impaired brain dopamine transporter activity with comparable [ 11 C]CFT reduction patterns in dopaminergic pathways. Crucially, PD patients demonstrated a significantly more pronounced reduction in left ventricular myocardial [ 18 F]MFBG uptake (SUVmean) versus APS patients, indicating marked cardiac sympathetic denervation in PD. Correlation analysis revealed a positive correlation between left ventral putamen SOR and global myocardial SUVmean in PD patients, contrasting with a negative correlation between right substantia nigra SOR and global myocardial SUVmean in the APS group. PD patients manifest concurrent significant impairment in both brain dopamine transporter function and cardiac sympathetic innervation. By contrast, APS patients show similar brain dopaminergic deficits alongside relatively preserved postganglionic cardiac sympathetic function. This distinct cardiac-brain disease pattern supports the utility of combined [ 11 C]CFT and [ 18 F]MFBG PET imaging for clinical diagnosis and differential diagnosis of PD.