Table 2. Comparison of Lesions Visible on MR1 vs MR2a.
| Abnormality | Scan finding, No. (%) of patients | Raw P value | |||||
|---|---|---|---|---|---|---|---|
| MR1 positive | MR1 negative | ||||||
| MR1 positive | MR2 | MR1 negative | MR2 | ||||
| Lesion persists | Lesion resolved | Remains negative | Shows new lesion | ||||
| Any | 34 (100) | 31 (91) | 3 (9) | 47 (100) | 47 (100) | 0 | .25 |
| Mass effect | |||||||
| Mass >25 mL | 2 (100) | 2 (100) | 0 | 79 (100) | 79 (100) | 0 | NC |
| Midline shift | 1 (100) | 1 (100) | 0 | 80 (100) | 80 (100) | 0 | NC |
| Cisternal compression | 1 (100) | 1 (100) | 0 | 80 (100) | 80 (100) | 0 | NC |
| Intra-axial | |||||||
| Contusion | 20 (100) | 20 (100) | 0 | 61 (100) | 61 (100) | 0 | NC |
| Traumatic axonal injury | 21 (100) | 20 (95) | 1 (5) | 60 (100) | 60 (100) | 0 | >.99 |
| Extra-axial | |||||||
| Hemorrhage | |||||||
| Epidural | 3 (100) | 3 (100) | 0 | 78 (100) | 78 (100) | 0 | NC |
| Subdural | 8 (100) | 7 (88) | 1 (12) | 73 (100) | 71 (97) | 2 (3) | >.99 |
| Subarachnoid | 14 (100) | 5 (36) | 9 (64) | 67 (100) | 66 (99) | 1 (1) | .03 |
| Other | |||||||
| Skull fracture | 0 | 0 | 0 | 81 (100) | 81 (100) | 0 | NC |
| Intraventricular hemorrhage | 10 (100) | 2 (20) | 8 (80) | 71 (100) | 71 (100) | 0 | .01 |
Abbreviations: MR1, first magnetic resonance scan after injury; MR2, second magnetic resonance scan after injury; NC, not calculated.
a
Eighty-one patients received a magnetic resonance scan within 72 hours (MR1) and at 2 to 3 weeks after injury (MR2). Lesions visible on the 2 scans were compared using the McNemar test for paired categorical data. Where reports were identical, no P value is shown. None of the P values was significant, assuming a 5% false discovery rate.