Table 6.
Morphology of reimaged dogs at MRI1 and MRI2
| Morphologic Parameters | Morphology at MRI1a | N | Morphology at MRI2a | N | P‐value, If Significant b | Bonferroni‐corrected Significance Level |
|---|---|---|---|---|---|---|
| Chiari‐like malformation | 31/36 (86%) | 36 | 33/36 (92%) | 36 | – | – |
| Cerebellar herniation in extension (mm) | 1.6 (0–4) | 19 | 2 (0–3.2) | 36 | – | – |
| Cerebellar herniation in flexion (mm) | 3 (0–6.5) | 36 | 2 (0–3.8) | 34 | – | – |
| Cerebellar indentation c | 31 (86%) | 36 | 26 (72%) | 36 | – | – |
| Atlantooccipital overlapping c | 7 (37%) | 19 | 12/19 (63%) | 19 | – | – |
| Dorsal band c , d | 12 (63%) | 19 | 16/19 (84%) | 19 | – | – |
| Syringomyelia e | 15 (42%) | 36 | 26/36 (72%) | 36 | – | – |
| Maximum syringomyelia height (%) | 61 (0–76.9) | 51 | 63.5 (0–81) | 36 | .0004 | .0024 |
| Syringomyelia lengthd | 2.5 (0–7) | 51 | 3 (0–8) | 36 | .0003 | .0021 |
| Foramen magnum height (mm) | 16 (11–20.1) | 54 | 17.3 (14.3–20.4) | 35 | .0001 | .0008 |
| Cr cranial cavity volume (mm3) | 78.2 (63.4–92.2) | 35 | 74.7 (60.6–99.4) | 34 | .0638 | – |
| Cd cranial cavity volume (mm3) | 12.4 (10.1–15.7) | 36 | 12.4 (10.4–17.3) | 34 | .1780 | – |
| Cd cranial cavity proportional volume (mm3) | 13.8 (10.6–16.4) | 38 | 14.8 (13–17.7) | 34 | .0505 | .2525 |
Significantly different findings at MRI2 are specified along with associated P‐values. Bonferroni‐corrected significance levels are also specified for each significant relationship.
MRI, magnetic resonance imaging. Prevalence values are listed as the number of dogs affected, followed by the percent of the cohort in which the abnormality was seen. Measurements are listed as “median (range)” (Cd: caudal; Cr: cranial).
Listed P‐vales reflect pairwise comparisons between MRI1 and MRI2. Only significant P‐values are listed.
Indicates presence of the abnormality.
The prevalence of both dorsal bands and atlantooccipital overlapping is reported only in dogs imaged in extension due to the influence of head position on the severity of these conditions.
Measured in vertebral body lengths.