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. 2021 Mar 10;36(7):1592–1602. doi: 10.1002/mds.28531

TABLE 2.

SN measurements

(a) Baseline: GLM‐ANOVA with group (PD, HV) as between‐group factors adjusted for age and sex as covariates
Healthy volunteers Parkinson's disease patients GLM‐ANOVA: group factor
Baseline All HV All PD % Change F P
Cohort I n = 41 n = 99
Volume (mm3) 273.2 ± 48.4 242.5 ± 50.2b −11.2 11.42 < 0.001
Corrected volume (Cvol) 0.19 ± 0.04 0.16 ± 0.04b −16.1 24.22 < 0.001
Signal‐to‐Noise Ratio (SNR) 112.1 ± 1.6 110.0 ± 1.6b −17.4 47.95 < 0.001
Contrast‐to‐noise ratio (CNR) 1.56 ± 0.23 1.25 ± 0.27b −20.3 48.26 < 0.001
Cohort II n = 23 n = 41
Volume (mm3) 260.4 ± 37.0 160.3 ± 63.6b −38.4 43.57 < 0.001
Corrected volume (Cvol) 0.19 ± 0.03 0.11 ± 0.05b −42.5 53.55 < 0.001
Signal‐to‐noise ratio (SNR) 109.8 ± 2.4 107.7 ± 2.1b −21.4 13.46 < 0.001
Contrast‐to‐noise ratio (CNR) 1.30 ± 0.39 1.01 ± 0.29b −22.7 10.76 < 0.01
(b) Longitudinal: GLM‐ANOVA with visit (V1, V2) as a within‐subject factor and group (PD, HV) as between‐group factor adjusted for age and sex as covariates
GLM‐ANOVA
Healthy volunteers Parkinson's disease patients Group factor Visit factor Group X visit
Longitudinal V1 V2 Annual rate of decline (%) V1 V2 Annual rate of decline (%) F P F P F P
Cohort I
Volume (mm3) 266.8 ± 51.3 268.9 ± 51.7 0.4 242.8 ± 49.2 214.1 ± 53.6b ‐5.8 26.91 < 0.001 8.36 0.004 4.12 0.043
Corrected volume (Cvol) 0.19 ± 0.04 0.19 ± 0.04 0.3 0.16 ± 0.04 0.14 ± 0.04b ‐5.6 54.96 < 0.001 7.96 0.005 3.67 0.056
Signal‐to‐noise ratio (SNR) 112.2 ± 1.8 112.4 ± 1.6 0.8 110.0 ± 1.7 110.3 ± 1.7a 1.5 73.53 < 0.001 1.60 0.200 0.02 0.880
Contrast‐to‐noise ratio (CNR) 1.58 ± 0.24 1.71 ± 0.25b 3.9 1.26 ± 0.29 1.31 ± 0.27a 1.9 90.38 < 0.001 4.15 0.042 1.00 0.322
Cohort II
Volume (mm3) 157.6 ± 69.1 119.0 ± 60.2b −10.2 5.32 0.024
Corrected volume (Cvol) 0.11 ± 0.05 0.08 ± 0.04b −10.3 5.04 0.024
Signal‐to‐noise ratio (SNR) 107.8 ± 2.1 107.1 ± 1.6a −3.7 1.87 0.200
Contrast‐to‐noise ratio (CNR) 1.03 ± 0.30 0.96 ± 0.24 −3.0 1.07 0.300

HV, healthy volunteer; PD, patients with Parkinson's disease.

Data represented as mean ± standard deviation.

Significant P values are indicated in bold.

a

t‐Test P < 0.05.

b

t‐Test P ≤ 0.001.