Table 2. Association of Whole-Body Hypothermia With Conventional MR Biomarkers and MR Spectroscopic Biomarkers.
| Outcome | Category | Participants, No. (%) | OR or MD (95% CI)a | P value | |
|---|---|---|---|---|---|
| Hypothermia group | Control group | ||||
| Inborn neonates (n = 76) | |||||
| Total participants, No. | 37 | 39 | |||
| Conventional MR imaging | |||||
| Basal ganglia and thalamic injury | 0 | 27 (73.0) | 30 (76.9) | 1.02 (0.37 to 2.86) | .97 |
| 1 | 4 (10.8) | 0 | |||
| 2 | 3 (8.1) | 2 (5.1) | |||
| 3 | 3 (8.1) | 7 (17.9) | |||
| Posterior limb of internal capsule | Normal | 30 (81.1) | 30 (76.9) | 0.74 (0.25 to 2.25) | .60 |
| Equivocal | 2 (5.4) | 1 (2.6) | |||
| Abnormal | 5 (13.5) | 8 (20.5) | |||
| White matter injury | 0 | 7 (18.9) | 3 (7.7) | 0.49 (0.20 to 1.21) | .12 |
| 1 | 4 (10.8) | 5 (12.8) | |||
| 2 | 22 (59.5) | 22 (56.4) | |||
| 3 | 4 (10.8) | 9 (23.1) | |||
| Cortical injury | 0 | 24 (64.9) | 27 (69.2) | 1.02 (0.40 to 2.61) | .97 |
| 1 | 8 (21.6) | 3 (7.7) | |||
| 2 | 1 (2.7) | 2 (5.1) | |||
| 3 | 4 (10.8) | 7 (17.9) | |||
| MR spectroscopy | |||||
| Thalamic NAA, mean (SD), mmol/kg wet weight | 8.04 (1.98) | 8.31 (1.13) | −0.28 (−1.62 to 1.07) | .68 | |
| NAA to choline PAR, mean (SD) | 0.86 (0.11) | 0.92 (0.12) | −0.06 (−0.15 to 0.03) | .16 | |
| NAA to creatinine PAR, mean (SD) | 1.54 (0.28) | 1.65 (0.21) | −0.11 (−0.30 to 0.09) | .26 | |
| Thalamic lactate to NAA PAR, median (IQR) | 0.13 (0.10 to 0.20) | 0.12 (0.09 to 0.18) | 1.02 (0.96 to 1.08) | .59 | |
| Outborn neonates (n = 173) | |||||
| Total participants, No. | 79 | 94 | |||
| Conventional MR imaging | |||||
| Basal ganglia and thalamic injury | 0 | 63 (79.7) | 72 (76.6) | 0.91 (0.44 to 1.87) | .80 |
| 1 | 3 (3.8) | 10 (10.6) | |||
| 2 | 7 (8.9) | 8 (8.5) | |||
| 3 | 6 (7.6) | 4 (4.3) | |||
| Posterior limb of internal capsule | Normal | 65 (82.3) | 76 (80.9) | 0.92 (0.43 to 1.99) | .84 |
| Equivocal | 3 (3.8) | 5 (5.3) | |||
| Abnormal | 11 (13.9) | 13 (13.8) | |||
| White matter injury | 0 | 15 (19.0) | 27 (28.7) | 1.26 (0.73 to 2.17) | .41 |
| 1 | 23 (29.1) | 20 (21.3) | |||
| 2 | 33 (41.8) | 39 (41.5) | |||
| 3 | 8 (10.1) | 8 (8.5) | |||
| Cortical injury | 0 | 62 (78.5) | 64 (68.1) | 0.62 (0.31 to 1.23) | .17 |
| 1 | 10 (12.7) | 20 (21.3) | |||
| 2 | 2 (2.5) | 7 (7.4) | |||
| 3 | 5 (6.3) | 3 (3.2) | |||
| MR spectroscopy | |||||
| Thalamic NAA, mean (SD), mmol/kg wet weight | 8.03 (1.89) | 7.99 (1.72) | 0.05 (−0.62 to 0.71) | .89 | |
| NAA to choline PAR, mean (SD) | 0.83 (0.21) | 0.84 (0.16) | −0.01 (−0.07 to 0.06) | .85 | |
| NAA to creatinine PAR, mean (SD) | 1.51 (0.30) | 1.50 (0.27) | 0.02 (−0.08 to 0.11) | .74 | |
| Thalamic lactate to NAA PAR, median (IQR) | 0.14 (0.11 to 0.20) | 0.14 (0.10 to 0.17) | 1.03 (0.98 to 1.09) | .18 | |
Abbreviations: MD, mean difference; MR, magnetic resonance; NAA, N-acetyl aspartate; OR, odds ratio; PAR, peak area ratio.
a
Odds ratios (calculated as the odds of being in next highest outcome category for the hypothermia group relative to the odds of being in next highest outcome category for the control group) were reported for conventional MR imaging. MDs (calculated as cooling group values minus control group values) were reported for MR spectroscopy.