Table 2.
Major findings from studies using IMR assays of plasma AD pathological markers
| Study, year | Diagnosis | Imaging | Assays | Major findings |
|---|---|---|---|---|
| Fan et al. 2018 [60] | 39 NC, 25 aMCI, 16 AD | 11C-PiB PET, MRI |
Aβ40 Aβ42 t-tau |
t-tau at 25.57 pg/ml cutoff identified PiB+ group at 93% sensitivity and 100% specificity; Aβ42 at 16.81 pg/ml cutoff had 87% sensitivity and 82% specificity. As for PiB− group, t-tau at 37.54 pg/ml and Aβ42 at 21.92 pg/ml had 100% sensitivity and specificity |
| Yang et al. 2018 [54] | 23 NC, 29 MCI, and 21 early AD | NA |
p-tau181 t-tau |
p-tau181 levels were significantly increased in MCI and early AD. To discriminate NC from the diseased subjects, 3.08 pg/ml cutoff achieved 79% sensitivity and 84% specificity |
| Yang et al. 2017 [43] | 66 NC, 24 MCI, 29 AD, 41 PD, 26 FTD, 29 VD | NA | t-tau | t-tau levels were lowest in NC and highest in AD (NC < VD < PD < MCI < FTD < AD); at 17.43 pg/ml cutoff t-tau had 86% sensitivity and 74% specificity for discriminating between NC and diseased subjects |
| Yang et al. 2017 [55] | 68 NC, 24 MCI, 31 early AD | NA |
Aβ42 t-tau |
Aβ42 × t-tau at 455.5 pg/ml discriminated AD from NC at 95% sensitivity and 97% specificity |
| Lue et al. 2017 [61] | 77 NC, 47 early AD | NA |
Aβ42 t-tau |
Composite marker Aβ42 × t-tau cutoff at 382.68 (pg/ml)2 distinguished AD from NC at 92% accuracy |
| Tzen et al. 2014 [62] | 20 NC, 25 aMCI and early AD | 11C-PiB PET |
Aβ40 Aβ42 t-tau |
To discriminate aMCI and AD combined from NC, t-tau 28.27 pg/ml cutoff had 92% sensitivity and 100% specificity; Aβ42/Aβ40 at cutoff 0.3693 had 84% sensitivity and 100% specificity; correlation (R2 = 0.326–0.449, P < 0.001) was detected between Aβ42/Aβ40 ratios and PiB-measured brain Aβ deposition |
| Chiu et al. 2014 [59] | 30 NC, 20 MCI, 10 early AD | MRI | t-tau | Significant negative correlation between t-tau and volumes of total gray matter, hippocampus, and amygdala, and functional measures (logical memory, visual reproduction, and verbal fluency) |
| Chiu et al. 2013 [58] | 66 NC, 22 MCI, 45 AD | NA |
Aβ40 Aβ42 t-tau |
Best discriminator between NC and patients (MCI and AD combined) was the composite marker of Aβ42 × t-tau at 96% sensitivity and 97% specificity |
| Chiu et al. 2012 [52] | 26 NC, 16 MCI, 18 AD | NA |
Aβ40 Aβ42 |
To discriminate aMCI and AD from NC, Aβ42 at 16.1 pg/ml cutoff had 85% sensitivity and 89% specificity; Aβ42/Aβ40 ratio at 0.303 cutoff had 85% sensitivity and 96% specificity |
AD Alzheimer’s disease, aMCI amnestic mild cognitive impairment, 11C-PiB Pittsburgh compound, FTD frontotemporal dementia, MCI mild cognitive impairment due to AD, MRI magnetic resonance imaging, NA not applicable, NC normal control, PET positron-emission tomography, PD Parkinson’s disease, VD vascular dementia