Diagnostic effectiveness of quantitative [18F]flutemetamol PET imaging for detection of fibrillar amyloid β using cortical biopsy histopathology as the standard of truth in subjects with idiopathic normal pressure hydrocephalus

Table 8 Accuracy of [ ¹⁸ F]flutemetamol quantitative diagnosis and positive and negative predictive values by Aβ pathology SoT in the 4 studies combined

Pathology standard of truth
SUVR type		SUVR/SoT, N (%)				N	(%)
Brain SUVR region	REF	TN n (%)	FN n (%)	FP n (%)	TP n (%)	Total	Accuracy^a	PPV^b	NPV^c
4G8% area
Ipsi	C	23 (62)	0 (0)	14 (38)	9 (100)	46	69.57	39.13	100.00
Contra	C	25 (68)	0 (0)	12 (32)	9 (100)	46	73.91	42.86	100.00
Comp	C	32 (86)	3 (33)	5 (14)	6 (67)	46	82.61	54.55	91.43
Ipsi	P	19 (50)	0 (0)	19 (50)	9 (100)	47	59.57	32.14	100.00
Contra	P	25 (66)	1 (11)	13 (34)	8 (89)	47	70.21	38.10	96.15
Comp	P	24 (63)	1 (11)	14 (37)	8 (89)	47	68.09	36.36	96.00
Bielschowsky silver plaque score
Ipsi	C	24 (89)	0 (0)	3 (11)	8 (100)	35	91.43	72.73	100.00
Contra	C	24 (89)	0 (0)	3 (11)	8 (100)	35	91.43	72.73	100.00
Comp	C	25 (93)	0 (0)	2 (7)	8 (100)	35	94.29	80.00	100.00
Ipsi	P	23 (82)	0 (0)	5 (18)	8 (100)	36	86.11	61.54	100.00
Contra	P	26 (93)	0 (0)	2 (7)	8 (100)	36	94.44	80.00	100.00
Comp	P	24 (86)	0 (0)	4 (14)	8 (100)	36	88.89	66.67	100.00
Thioflavin S plaque score
Ipsi	C	31 (97)	2 (22)	1 (3)	7 (78)	41	92.68	87.50	93.94
Contra	C	29 (91)	1 (11)	3 (9)	8 (89)	41	90.24	72.73	96.67
Comp	C	27 (84)	0 (0)	5 (16)	9 (100)	41	87.80	64.29	100.00
Ipsi	P	25 (76)	1 (11)	8 (24)	8 (89)	42	78.57	50.00	96.15
Contra	P	30 (91)	1 (11)	3 (9)	8 (89)	42	90.48	72.73	96.77
Comp	P	28 (85)	1 (11)	5 (15)	8 (89)	42	85.71	61.54	96.55
Overall pathology
Ipsi	C	34 (100)	1 (7)	0 (0)	13 (93)	48	97.92	100.00	97.14
Contra	C	33 (97)	0 (0)	1 (3)	14 (100)	48	97.92	93.33	100.00
Comp	C	34 (100)	0 (0)	0 (0)	14 (100)	48	100.00	100.00	100.00
Ipsi	P	30 (86)	1 (7)	5 (14)	13 (93)	49	87.76	72.22	96.77
Contra	P	31 (89)	0 (0)	4 (11)	14 (100)	49	91.84	77.78	100.00
Comp	P	35 (100)	1 (7)	0 (0)	13 (93)	49	97.96	100.00	97.22

C = cerebellum; Comp = composite; Contra = contralateral; FN = false negatives; FP = false positives; Ipsi = ipsilateral; N = number of patients; NPV = negative predictive value; P = pons; PPV = positive predictive value; REF = PET imaging brain reference region; ROC = receiver-operator curve; SoT = standard of truth; TN = true negatives; TP = true positives; SUVR = standard uptake value ratio.

ISSN: 2051-5960