Table 1.

Characteristics of subjects who underwent 18F-florbetapir-positron emission tomography (amyloid-PET) and lumbar puncture (LP) within a 365-day interval

	Amyloid-PET positive*	Amyloid-PET negative°	p value
n	37	7
Age	71.4 ± 7.5	72.9 ± 3.6	0.76
M:F	13:24	3:4	0.69
Interval LP/amyloid-PET (days)	168.6 ± 119.5	246.4 ± 115.1	0.35
Aβ1-42 (pg/ml)	542.2 ± 119.2	842.3 ± 341.9	0.001
t-tau (pg/ml)	700.5 ± 493.3	681.3 ± 593.1	0.83
p-tau (pg/ml)	83.9 ± 38.5	67 ± 31.8	0.34
t-tau/Aβ1-42	1.30 ± 0.9	0.90 ± 1.0	0.13
p-tau/Aβ1-42	0.15 ± 0.07	0.09 ± 0.06	0.01
Amyloid-PET SUVR GM mean	1.47 ± 0.21	0.98 ± 0.10	< 0.0001
Amyloid-PET SUVR Ant Cing	1.49 ± 025	0.99 ± 0.16	< 0.0001
Amyloid-PET SUVR frontal	1.36 ± 0.25	0.89 ± 0.19	< 0.0001
Amyloid-PET SUVR parietal	1.28 ± 0.19	1.04 ± 0.15	0.005
Amyloid-PET SUVR post Cing	1.55 ± 0.22	0.97 ± 0.20	< 0.0001
Amyloid-PET SUVR precuneus	1.61 ± 0.27	1.02 ± 0.22	< 0.0001
Amyloid-PET SUVR temporal	1.50 ± 0.19	1.04 ± 0.15	< 0.0001

Data are expressed as mean ± SD, unless otherwise specified. p values by unpaired t test. *Among amyloid-PET-positive patients, 14 were diagnosed of Alzheimer’s disease, 2 cerebral amyloid angiopathy, 20 mild cognitive impairment (MCI) and 1 mixed dementia. °Four amyloid-PET-negative patients had a diagnosis of MCI, 1 frontotemporal dementia, 1 mixed dementia and 1 dysthymic dementia

All significant data (p value < 0.05) are presented in italic

Abbreviations: M males, F females, Aβ_1-42 amyloid-β_1-42, t-tau total tau, p-tau phosphorylated tau, SUVR standardised uptake value relative ratio, GM grey matter