Table 2.

Imaging classification relative to final clinical diagnosis: discriminative measures

	All patients	Symptom duration (years)		Symptom duration, clinical follow-up (years)
		≤2	>2	≤2, ≤2	≤2, >2	>2, ≤2	>2, >2
		Idiopathic Parkinson’s disease
Sensitivity	84% (81/96)	77% (23/30)	88% (58/66)	67% (6/9)	81% (17/21)	50% (4/8)	93% (54/58)
Specificity	97% (69/71)	92% (23/25)	100% (46/46)	92% (12/13)	92% (11/12)	100% (20/20)	100% (26/26)
Positive predictive value	98% (81/83)	92% (23/25)	100% (58/58)	86% (6/7)	94% (17/18)	100% (4/4)	100% (54/54)
Negative predictive value	82% (69/84)	77% (23/30)	85% (46/54)	80% (12/15)	73% (11/15)	83% (20/24)	87% (26/30)
Atypical parkinsonian syndrome
Sensitivity	82% (58/71)	72% (18/25)	87% (40/46)	62% (8/13)	83% (10/12)	80% (16/20)	92% (24/26)
Specificity	98% (94/96)	97% (29/30)	98% (65/66)	89% (8/9)	100% (21/21)	88% (7/8)	100% (58/58)
Positive predictive value	97% (58/60)	95% (18/19)	98% (40/41)	89% (8/9)	100% (10/10)	94% (16/17)	100% (24/24)
Negative predictive value	88% (94/107)	81% (29/36)	92% (65/71)	62% (8/13)	91% (21/23)	64% (7/11)	97% (58/60)
Multiple system atrophy
Sensitivity	85% (29/34)	88% (7/8)	85% (22/26)	67% (2/3)	100% (5/5)	88% (7/8)	83% (15/18)
Specificity	96% (25/26)	91% (10/11)	100% (15/15)	83% (5/6)	100% (5/5)	100% (9/9)	100% (6/6)
Positive predictive value	97% (29/30)	88% (7/8)	100% (22/22)	67% (2/3)	100% (5/5)	100% (7/7)	100% (15/15)
Negative predictive value	83% (25/30)	91% (10/11)	79% (15/19)	83% (5/6)	100% (5/5)	90% (9/10)	67% (6/9)
Progressive supranuclear palsy
Sensitivity	88% (21/24)	90% (9/10)	86% (12/14)	80% (4/5)	100% (5/5)	75% (6/8)	100% (6/6)
Specificity	94% (34/36)	100% (9/9)	93% (25/27)	100% (4/4)	100% (5/5)	78% (7/9)	100% (18/18)
Positive predictive value	91% (21/23)	100% (9/9)	86% (12/14)	100% (4/4)	100% (5/5)	75% (6/8)	100% (6/6)
Negative predictive value	92% (34/37)	90% (9/10)	93% (25/27)	80% (4/5)	100% (5/5)	78% (7/9)	100% (18/18)

Data are % (calculation).