Table 2.
Measurements of brain volume, perfusion, and tissue oxygenation
| NC n=21 |
aMCI n=32 |
P Value | ||
|---|---|---|---|---|
| Brain volume | ||||
| ICV, ml | 1516 (212) | 1550 (212) | 0.561 | |
| TBV, ml | 1110 (98) | 1140(107) | 0.299 | |
| GM, ml | 608 (47) | 611 (56) | 0.852 | |
| WM, ml | 502 (56) | 529 (57) | 0.088 | |
| nTBV, %ICV | 73.9 (6.9) | 74.1 (5.3) | 0.938 | |
| nGM, %ICV | 40.6 (4.6) | 39.7 (3.1) | 0.393 | |
| nWM, %ICV | 33.3 (2.7) | 34.3 (2.7) | 0.177 | |
| Regional brain perfussion | ||||
| Diameter, mm | RICA | 4.55 (0.74) | 4.35 (0.61) | 0.290 |
| LICA | 4.49 (0.52) | 4.48 (0.66) | 0.950 | |
| RVA | 3.12 (0.62) | 3.04 (0.45) | 0.581 | |
| LVA | 3.21 (0.47) | 3.20 (0.48) | 0.925 | |
| TAMV, cm/s | RICA | 24.3 (7.7) | 24.4 (6.8) | 0.938 |
| LICA | 22.5 (7.5) | 21.6 (6.6) | 0.663 | |
| RVA | 15.0 (4.7) | 14.6 (5.8) | 0.773 | |
| LVA | 15.0 (3.0) | 14.5 (3.9) | 0.600 | |
| CBF, ml/min | RICA | 233 (80) | 211 (46) | 0.211 |
| LICA | 207 (58) | 201 (64) | 0.756 | |
| RVA | 73 (36) | 64 (30) | 0.349 | |
| LVA | 76 (31) | 70 (27) | 0.492 | |
| Global brain perfusion | ||||
| TCBF, ml/min | 588 (101) | 547 (97) | 0.142 | |
| nTCBF, ml/min/100ml | 53.1 (8.7) | 48.1 (8.3) | 0.038 | |
| CVR, mmHg•min/ml | 0.152 (0.025) | 0.171 (0.033) | 0.029 | |
| Brain tissue oxygenaton indices | ||||
| SaO2, % | 97.0 (1.6) | 97.2 (1.3) | 0.570 | |
| TOI, % | 66.4 (4.1) | 65.5 (5.6) | 0.562 | |
| OEF, % | 31.4 (4.3) | 32.5 (5.9) | 0.524 | |
| CMRO2, µmol/100g/min | 127.1 (17.1) | 113.6 (15.7) | 0.010 | |
Values are the mean (standard deviation). NC = cognitively normal controls; aMCI = amnestic mild cognitive impairment; ICV = intracranial volume; TBV = total brain-tissue volume; nTBV = normalized TBV; WM = white matter; nWM = normalized WM; GM = grey matter; nGM = normalized GM; RICA = right internal carotid artery; LICA = left internal carotid artery; RVA = right vertebral artery; LVA = left vertebral artery; TAMV = time-averaged mean velocity; CBF = cerebrovascular blood flow; TCBF = total CBF; nTCBF = normalized TCBF; CVR = cerebrovascular resistance; SaO2 = arterial blood oxygen saturation; TOI = tissue oxygenation index; OEF = oxygen extraction fraction = (SaO2-TOI)/ SaO2; CMRO2 = cerebral metabolic rate of oxygen = nTCBF×(SaO2-TOI) × (8.337/1.06).