Table 3.
Estimated marginal means of vermis‐ and brainstem‐specific markers on magnetic resonance imaging in fetuses with cystic posterior fossa malformations, according to group defined by standard criteria (vermian size and brainstem–vermis (BV) angle), and in brain‐normal controls
| Variable | Controls (n = 148) | Group 1 (n = 74) | Group 2 (n = 24) | Group 3 (n = 44) | P |
|---|---|---|---|---|---|
| Number of vermian lobules* | 6.52 ± 2.68 | 5.61 ± 2.68 | 5.05 ± 2.68 | 4.11 ± 2.68 | < 0.001 |
| Area of vermis (mm2) | 118.09 ± 17.11 | 110.05 ± 17.20 | 93.78 ± 17.53 | 81.40 ± 17.31 | < 0.001 |
| Area of mesencephalon (mm2) | 41.16 ± 0.65 | 40.05 ± 0.96 | 36.16 ± 1.63 | 38.18 ± 1.23 | 0.015 |
| Area of pons (mm2) | 77.41 ± 9.56 | 73.36 ± 9.62 | 67.74 ± 9.85 | 72.33 ± 9.70 | 0.001 |
| Area of medulla oblongata (mm2) | 48.95 ± 10.15 | 49.01 ± 10.18 | 48.10 ± 10.29 | 45.90 ± 10.22 | 0.236 |
Data are given as mean ± SD for average gestational age of 25.23 weeks.
Effect of gestational age on parameters was eliminated using analysis of covariance.
*
In Groups 1–3, number of lobules is based on mean value of three observers.
Groups defined as follows: normal vermian area and BV angle < 25° (Group 1); reduced vermian area and/or BV angle of 25–45° (Group 2); reduced vermian area and BV angle > 45° (Group 3; Dandy–Walker malformation group).