# Discriminating between proposed Brain-First and Body-First Parkinson’s disease using conventional and radiomics-enhanced dopamine transporter SPECT image analysis

## TL;DR

This study investigates whether dopamine transporter SPECT imaging can distinguish between two proposed Parkinson’s disease subtypes, finding that imaging does not separate them at diagnosis.

## Contribution

The study is the first to evaluate radiomics-enhanced and conventional DAT-SPECT imaging for differentiating 'Brain-First' and 'Body-First' Parkinson’s subtypes.

## Key findings

- DAT-SPECT asymmetry indices and DaTQUANT metrics did not differ between 'Brain-First' and 'Body-First' subtypes.
- Radiomics-based classification showed poor discrimination (AUC ≈ 0.46) between the two subtypes.
- 'Body-First' patients had worse non-motor progression, including higher MCI prevalence and greater MMSE decline.

## Abstract

Two Parkinson’s disease subtypes—“Brain-First” and “Body-First”—have been proposed based on putative sites of onset. We examined whether “Body-First” markers relate to more symmetric striatal [123I]-FP-CIT uptake and whether imaging could discriminate the subtypes. In a retrospective cohort of 158 de novo PD patients imaged at diagnosis and followed for six years, patients were classified as “Body-First” if baseline REM sleep behavior disorder, constipation, or neurogenic orthostatic hypotension was present. DaTQUANT provided semiquantitative metrics; a radiomics-based classifier was also trained on DAT-SPECT images. Neither asymmetry indices nor other DaTQUANT measures differed between groups (all p > 0.05). Radiomics showed poor discrimination (AUC ≈ 0.46). Clinically, “Body-First” patients displayed a more adverse course, with higher MCI prevalence and greater MMSE decline and neuropsychiatric burden, whereas motor severity and complications were comparable between groups. These data suggest DAT-SPECT—conventional or radiomics-enhanced—does not separate proposed subtypes at diagnosis, although “Body-First” features forecast worse non-motor progression.