Diagnosis of Multiple System Atrophy-Parkinsonian Type [MSA-P] from Atypical Parkinsonism with Dual Tracer (FDG + DOPA) PET/MRI Brain

Objective: This case report demonstrates the potential of dual tracer imaging (fluorodeoxyglucose + dihydroxyphenylalanine (FDG + DOPA)) positron emission tomography/magnetic resonance imaging (PET/MRI) brain in diagnosing and distinguishing the patients with multiple system atrophy-Parkinsonian type (MSA-P) from atypical Parkinsonism. Methods: A 65-year-old male presented with postural instability, urinary symptom in form of urgency, hesitancy, precipitancy followed by incontinence, slowness of all activity of daily living (ADL) with stiffness of all limbs, slurred speech and difficulty in swallowing for four years. It was clinically suspected as atypical Parkinson’s disease. The DOPA PET/MRI revealed asymmetric reduced patchy uptake in bilateral striatum qualitatively and quantitatively more prominently in bilateral putamen (right> left—maximum standardised uptake value (SUVmax): putamen left 2.18; right 1.91; caudate nucleus left 2.71; right 2.62). Bilateral putamen is atrophic with heterogeneous signal changes. Midbrain Pons ratio measures 0.6 (reported threshold of 0.52). Results: All of these features when put together help us to point it towards the MSA-P which was further confirmed by 18F-FDG study which showed regional FDG hypometabolism in bilateral putamen with relative sparing bilateral caudate, palladium and thalamus. Conclusion: Dual tracer PET/MRI will be the key to reliable uses in the diagnosis of clinically suspected neurodegenerative disorder and accurate prediction of therapeutic intervention.