Abnormal dopamine transporter imaging in pure autonomic failure – a follow-up study

<h3>Introduction</h3> Abnormal dopaminergic transporter imaging in pure autonomic failure (PAF) is a potential biomarker of central nervous system involvement, as described in our pilot study. In this follow-up study, we evaluated the prevalence of abnormal DaTSCANs in a larger, prospective cohort of patients with PAF, and assessed the rate of phenoconversion to more widespread alpha synucleinopathies. <h3>Methods</h3> Consecutive PAF patients underwent a multimodal assessment including DaTSCAN, as part of part of the Queen Square Autonomic Prodromal Project (QSA-PRODOMAL). <h3>Results</h3> 70 patients with PAF with a median disease duration of 6 (IQR 3-10) years were identified. 22 developed a more widespread synucleinopathy (7 Parkinson’s disease, 4 dementia with Lewy bodies, 2 multiple system atrophy-cerebellar [MSA-C], 9 multiple system atrophy-parkinsonian). All phenoconverters had an abnormal DaTSCAN, apart from 2 patients who converted to MSA-C. In patients who underwent DaTSCAN while still retaining a PAF phenotype, the median lag between imaging and phenoconversion was 8 IQR (4-16) months. 48 patients retained a PAF phenotype at last follow-up and 4 of them had an abnormal DaTSCAN. These had a clinical REM sleep behaviour disorder. There were no differences in demographics, autonomic function, or plasma catecholamine spillover between PAF patients with normal or an abnormal DaTSCAN. <h3>Conclusion</h3> DaTSCAN is a biomarker of central nervous system involvement in PAF and can predict phenoconversion to more widespread alpha-synucleinopathies in patients with a premotor phenotype.