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

Table 2 Substantia nigra sonography findings indicating non-TD PD rather than MSA-P

	Total patients		Patients with disease duration ≤3 years
	SN_L ≥ 18 mm²	SN_L ≥ 25 mm²	SN_L ≥ 18 mm²	SN_L ≥ 25 mm²
Sensitivity, %	74.1	46.3	69.8	41.3
Specificity, %	61.6	80.2	52.2	73.9
PPV, %	76.8	80.0	66.7	68.4
NPV, %	58.2	46.6	55.8	47.9

Non-TD PD non-tremor dominant Parkinson’s disease, MSA-P multiple system atrophy with predominant parkinsonism, SN_L the larger value of bilateral SN hyperechogenicity, PPV positive predictive value, NPV negative predictive value

ISSN: 2047-9158