Role of magnetic resonance planimetry and magnetic resonance parkinsonism index in discriminating Parkinson’s disease and progressive supranuclear palsy: a retrospective study based on 1.5 and 3 T MRI

Figures & data

Figure 1 MRI brain images of this study in orthogonal planes showing measurement annotations and appropriate planes for measurements.

Notes: (A) Coronal FLAIR image shows measurement of right superior cerebellar peduncle. (B) Midsagittal T2W image represents the area of midbrain and pons. (C) T1W parasagittal image depicts middle cerebellar peduncle measurement.
Abbreviation: FLAIR, fluid-attenuated inversion recovery.

Figure 2 Box plot of P/M ratio in patients with PSP.

Notes: Median is shown as a line across each box, and vertical solid lines (whiskers) show lower and upper values: PSP patients (median =4.50; range, 3.29–6.11), PD patients (median =3.13; range, 2.35–3.91), control participants (median =3.0; range, 2.37–3.93).
Abbreviations: P/M, pons area–midbrain area ratio; PD, Parkinson’s disease; PSP, progressive supranuclear palsy.

Figure 3 Box plot of MCP/SCP ratio in PSP patients (median =4.75; range, 3.14–6.35), PD patients (median =2.97; range, 1.92–4.77), control participants (median =3.0; range, 2.38–4.29).

Abbreviations: P/M, pons area–midbrain area ratio; PD, Parkinson’s disease; PSP, progressive supranuclear palsy; SCP, superior cerebellar peduncle.

Table 1 Demographic data of PD and PSP patients along with healthy control participants involved in this study

		HC	PD	PSP
No of participants		34	34	34
Mean age (years) at evaluation		66.14±7.53	66.76±6.28,	66.76±6.27
Sex	Male	17	20	19
	Female	17	14	15
Duration of disease (years)		–	6.3±3.86	6.6±2.82
Hoehn–Yahr score		–	2.5 (1.5–5)	4 (3–5)

Abbreviations: HC, healthy control; PD, Parkinson’s disease; PSP, progressive supranuclear palsy.

Table 2 MR planimetric measurements in three different subgroups of this study

Participant groups	Midbrain area (mm^2)	Pons area (mm^2)	SCP width (mm)	MCP width (mm)
PSP (n=34)	96.02±13.47	430.73±49.02	2.81±0.47	12.78±1.57
PD (n=34)	145.58±30.17	455.29±60.76	4.33±0.68	12.81±1.99
HC (n=34)	149.41±12.53	457.64±38.06	4.36±0.43	13.4±1.31

Note: Values are medians and mean ± SD.

Abbreviations: HC, healthy control; MCP, middle cerebellar peduncle; PD, Parkinson’s disease; PSP, progressive supranuclear palsy; SCP, superior cerebellar peduncle.

Figure 4 Box plot of MRPI in PSP patients (median =21; range, 12.92–30.56), PD patients (median =9.5; range, 5.89–14.9), control participants (median =9.6; range, 6.67–14.29). MRPI values are higher in PSP patients compared to PD and HC.

Abbreviations: HC, healthy controls; MRPI, Magnetic Resonance Parkinsonism Index; PD, Parkinson’s disease; PSP, progressive supranuclear palsy.

Table 3 Sensitivity and specificity of MRPI for the differentiation of PSP and PD

Statistical values	MRPI value	MCP/SCP value	P/M value
Cut-off value	≥13.5	≥3.2	≥4.2
Sensitivity (%)	100	85	85.71
Specificity (%)	100	92.86	91.67
PPV (%)	100	94.44	94.74
NPV (%)	100	81.25	78.57
Diagnostic accuracy (%)	100	88.23	87.87

Abbreviations: MRPI, Magnetic Resonance Parkinsonism Index; NPV, negative predictive value; PD, Parkinson’s disease; P/M, pons area–midbrain area ratio; PPV, positive predictive value; PSP, progressive supranuclear palsy; SCP, superior cerebellar peduncle.

Table 4 All pairwise multiple comparison procedures taking MRPI values

Comparison	P<0.001	Difference
PSP vs PD	Yes	Significant
PSP vs control	Yes	Significant
Control vs PD	No	Not significant

Note: P values were determined with Mann–Whitney U test.

Abbreviations: MRPI, Magnetic Resonance Parkinsonism Index; PD, Parkinson’s disease; PSP, progressive supranuclear palsy.