Article Figures & Data
Figures
- Fig. 1.
Exemplary graphic illustration of the clustering procedure (for T2r). Upper row: Representative model-based magnetization transfer parameter maps used for further classification. Middle row: After anatomic transformation of the 3D T1 template on the magnetization transfer parameter maps, the mMT values are extracted from the VOIs highlighted in red (EC): the hippocampal body (HB), hippocampal head (HH), insula (IN), and inferior and middle temporal neocortex (TP). Lower row: Plots of a single-parameter classification (T2r) for the subregions EC, HH, and HB. The axes correspond to the largest orthogonal eigenvectors found by the principal component analysis. Patients (n = 54) with Alzheimer disease (AD) and mild cognitive impairment (MCI) and healthy controls (CTRLs) within the EC (A), HH (B), and HB (C) were classified into 4 (CTRL/MCI, CTRL, MCI, and AD/MCI) clusters (AD [red], MCI [blue], and CTRLs [green]). Cluster selectivity reached 0.87 for A, 0.84 for B, and 0.86 for C. The strongest effects of changes within the macromolecular matrix were detected within the mesiotemporal lobe.
- Fig. 2.
Cluster selectivity for the mMT parameters incorporated into the classification of the 5 VOIs and parameters (MTR, T2r, T2f, F, kr, kf, subset 1 and subset 2). The selectivity of the classification reached 0.92 (50 of 54 subjects) for subset 2 in the entorhinal cortex. The multiparameter classification of subset 1 revealed significantly improved selectivity of the patients with AD and MCI and CTRLs compared with MTR.
Tables
Demographic data, MR imaging gray matter/total intracranial volume ratio, Mini-Mental State Examination, and neuropsychological test (CERAD-NAB) parametersa
Characteristics Control Mean Control SD MCI Mean MCI SD AD Mean AD SD No. 18 18 18 Age (yr) 71.61 9.2 70.83 10.1 70.39 9.9 Education 12.78 3.11 11.28 1.99 11.00 3.30 Men/women 9: 9 9: 9 9: 9 MRI TIV/GM ratio (GM fraction) 2.61 0.28 2.82 0.42 2.86 0.43 MMSE (30) 29.50 0.7 28.67 1.49 24.56b 3.45 CERAD Verbal fluency (24)c 24.89 7.28 16.06b 5.07 10.44b 3.88 Modified BNT (15) 14.56 0.78 14.50 0.99 12.33b 2.50 Word list: delayed recall (10) 8.28 1.60 6.50b 2.30 2.33b 1.45 Word list: learning (30) 22.22 3.06 19.61 4.27 12.94b 5.83 Constructional praxis (11) 10.78 0.95 10.56 0.78 9.39b 1.91 Constructional praxis: delayed recall (11) 9.83 2.15 9.39 2.06 4.28b 3.44 CERAD total score (101) 90.56 15.82 76.62b 15.47 51.71b 19.01 Note:—BNT indicates Boston Naming Test; TIV, total intracranial volume; GM, gray matter; MMSE, Mini-Mental State Examination.
↵a Maximum scores of test subunits are in brackets
↵b One-way ANOVA (P < .05).
↵c Verbal fluency does not have a ceiling when administered using standard instructions as part of the CERAD. For calculation, a cap of 24 was placed on verbal fluency, which represents 1 SD above the normal aging population mean.
