Article Figures & Data
Figures
- Fig 1.
A, Illustration of spectroscopic VOI in the central region in axial (left hemisphere) and coronal (right hemisphere) T2-weighted planscan images (left, upper and lower row). Sample spectra (TR/TE, 2000/140 ms; H2O-suppressed) of a healthy control (right, upper row) and patient IV/7 (Table 1) (right, lower row). B, 3D DTT (left) with intersection lines (yellow) shown at the level of FA/MD measurements (precentral gyrus, corona radiata, internal capsule, cerebral peduncles, pons, and pyramid). Fibers are projected onto axial FA (right/upper row, precentral gyrus) and MD maps (right/lower row, internal capsule) to allow a guided region-of-interest placement along the corticospinal tract. FA and MD statistics were additionally averaged on the CSTs as a whole to account for a region-independent analysis.
- Fig 2.
A, NAA/Cho and NAA/PCr metabolite ratios for patient subgroups and controls. Both parameters are lowest in group IV (EE probable/definite [prob./def.]). B, FA boxplots of the central region for groups I–IV. Mean FA values of groups III (EE clinically possible [clin. poss.]) and IV (prob./def.) were markedly lower in the upper 3 regions of measurements (Table 3).
Tables
Patient No. UMN† MRS DTI MRS/DTI TMS‡ DENERV§ Group IV 1 + ++ ++ true pos. NA + 2 + + + true pos. – + 3 + ++ ++ true pos. – – 4 + ++ ++ true pos. + – 5 + ++ ++ true pos. + + 6 + + + true pos. – + 7 + ++ ++ true pos. + + Group III 1 + ++ ++ true pos. + – 2 – ++ ++ false pos. NA + 3 – – – true neg. – – 4 – – – true neg. + + 5 – + – true neg. – + 6 – – – true neg. + + 7 – – + true neg. NA + Group II 1 – – – true neg. + – 2 – – – true neg. – – 3 – ++ – true neg. – + 4 – – – true neg. – – Note:—MRS indicates MR spectroscopy; UMN, upper motor neuron; TMS, transcranial magnetic stimulation; DENERV, denervation; true pos., true-positive; false pos., false positive; true neg., true negative; NA, not applicable; DTI, diffusion tensor imaging.
* ++ for MRS indicates NAA/Cho reduction beyond double SD; + beyond single SD. For DTI, ++ indicates 2 or more regions with FA below double SD; + just 1 region, respectively. −indicates a negative result. Reduction beyond the single SD threshold for MRS and beyond the double SD threshold in 1 region for DTI is regarded as a pathologic result of the MRS/DTI combination; discordance is graded as negative. Note that patient III/1 had primary lateral sclerosis but was subgrouped into the “clinically possible” group (III) due to his initial EE rating. DTI and MRS concurrently are false-positive in 1 patient with lower motor neuron involvement only (patient III/2).
† Clinical evidence for upper motor neuron involvement.
‡ Pathologic central conduction times in transcranial magnetic stimulation.
§ Presence or absence of generalized denervation.
- Table 2:
NAA/Cho and NAA/PCr metabolite ratios and absolute molar concentrations of NAA, Cho, and PCr (mmol/L brain tissue, mM) for patient subgroups and healthy controls (group Ia)
Group NAA/Cho NAA/PCr NAA (mM) Cho (mM) PCr (mM) IV* mean 1.72 1.62 9.79 1.88 8.19 SD 0.20 0.11 0.70 0.21 0.70 III mean 2.08 1.83 10.36 1.64 7.61 SD 0.36 0.18 1.92 0.21 1.03 II mean 2.10 1.78 10.26 1.60 7.78 SD 0.25 0.09 1.77 0.23 1.16 Ia mean 2.11 1.82 12.64 2.00 9.15 SD 0.14 0.12 1.16 0.21 1.24 Note:—NAA indicates N-acetylaspartate; Cho, choline; PCr, phosphocreatine.
* Both metabolite ratios are lowest in group IV.
- Table 3:
DTI group results and Mann-Whitney–Wilcoxon test for comparison of mean FA with healthy controls (group Ib)*
FA Pyramid Pons Peduncle Capsule Cent. Semi. Precent. Gyr. FA CST MD CST Group IV Mean 456.07 489.71 593.93 570.93 426.21 356.21 510.64 901.14 SD 64.98 111.86 62.62 55.01 84.69 48.50 36.10 31.99 MWW (P = .062) (P = .001) (P = .001) (P < .001) (P > .05) (P > .05) Group III Mean 508.71 553.64 617.86 612.64 435.93 417.86 510.71 932.93 SD 71.20 60.87 64.34 30.82 67.28 85.67 13.82 110.01 MWW (P > .05) (P = .022) (P < .001) (P = .116) (P > .05) (P > .05) Group II Mean 498.75 531.00 582.38 643.75 475.75 449.75 525.13 888.63 SD 64.25 45.76 97.70 51.24 63.29 34.02 17.04 50.71 Group Ib (controls) Mean 495.32 577.29 592.06 648.34 531.66 475.09 524.25 897.10 SD 63.47 66.97 65.80 48.97 53.97 50.41 24.58 34.92 Note:—MWW indicates Mann-Whitney–Wilcoxon test; Cent. Semi., centrum semiovale; Precent. Gyr., precentral gyrus; DTI, diffusion tensor imaging; FA, fractional anisotropy.
* The lowest mean FA in comparison with controls is found in the internal capsule, centrum semiovale, and the precentral gyrus of group IV (EE clinically probable/definite) and the internal capsule and centrum semiovale for patients of group III (EE clinically possible). The rightmost FA/MD CST columns illustrate diffusion characteristics averaged for the entire CST. FA ranges from 1000 (maximum anisotropy) to 0 (no anisotropy). MD exhibits statistically significant differences with elevation in the internal capsule in group IV compared with healthy controls (data not shown).
