The role of substantia nigra sonography in the differentiation of Parkinson’s disease and multiple system atrophy

Abstract Background The differential diagnosis of Parkinson’s disease (PD) and multiple system atrophy (MSA) remains a challenge, especially in the early stage. Here, we assessed the value of transcranial sonography (TCS) to discriminate non-tremor dominant (non-TD) PD from MSA with predominant parkinsonism (MSA-P). Methods Eighty-six MSA-P patients and 147 age and gender-matched non-TD PD patients who had appropriate temporal acoustic bone windows were included in this study. All the patients were followed up for at least 2 years to confirm the initial diagnosis. Patients with at least one substantia nigra (SN) echogenic size ≥18 mm2 were classified as hyperechogenic, those with at least one SN echogenic size ≥25 mm2 was defined as markedly hyperechogenic. Results The frequency of SN hyperechogenicity in non-TD PD patients was significantly higher than that in MSA-P patients (74.1% vs. 38.4%, p