Table 3. Summary of age-corrected Quantitative MRI metrics.
| qMRI Metric | Level | Mean Difference | P Value | SEM | Individuals with Progression |
|---|---|---|---|---|---|
| CSA (mm2) | Rostral | -0.34 ± 1.08 | 0.07 | 0.95 | 0 |
| MCL | -3.5 ± 5.4 | 0.003 | 2.94 | 3 | |
| FA | Rostral | -0.027 ± 0.037 | 0.001 | 0.018 | 6 |
| MCL | -0.038 ± 0.050 | 0.0007 | 0.029 | 4 | |
| Caudal | -0.016 ± 0.049 | 0.06 | 0.025 | 4 | |
| T2*WI WM/GM | Rostral | +0.006 ± 0.018 | 0.09 | 0.008 | 4 |
| MCL | +0.005 ± 0.039 | 0.21 | 0.034 | 0 | |
| Caudal | +0.012 ± 0.033 | 0.03 | 0.022 | 3 | |
| MTR (%) | Rostral | -0.80 ± 3.2 | 0.12 | 1.26 | 2 |
| MCL | -1.1 ± 2.8 | 0.03 | 3.10 | 0 | |
| Composite Score (t10) | -2.2 ± 2.2 | 0.00004 | 0.316 | 7 | |
Group results are displayed for the qMRI metric differences between baseline and follow-up, reported as mean ± SD. P values are reported for single-tailed paired t tests. SEM values are derived from our previous reliability study, and the SEM of CSA was measured in 5 healthy subjects and 11 DCM patients.[23] The composite score is calculated as an average of z scores for each metric, which is expected to follow a t distribution with 10 d.f.s under the null hypothesis. The number of individuals with progression detected by each measure is displayed (z < -2.65 or t10 < -3.30, p<0.004, one-tailed, corrected for multiple comparisons). CSA: cross-sectional area; d.f.s: degrees of freedom; FA: fractional anisotropy; MCL: maximally compressed level; MTR: magnetization transfer ratio; SEM: standard error of measurement