Age and MR measurements from symptomatic fragile X premutation carriers and control participants
| Age (yr) | Pons AP (mm) | Pons Trans (mm) | Pons RC (mm) | MCP R (mm) | MCP L (mm) | IV Height (mm) | Ant Horn (mm) | Fr. Cereb-Vent Index | Evan’s Index | III Width (mm) | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Control participants | |||||||||||
| Average | 66.1 | 26 | 31 | 29 | 18 | 18 | 11 | 36 | 0.32 | 0.28 | 6.1 |
| Maximum | 76.0 | 28 | 33 | 31 | 19 | 22 | 14 | 40 | 0.35 | 0.31 | 9.0 |
| Minimum | 56.0 | 23 | 27 | 26 | 15 | 14 | 10 | 31 | 0.28 | 0.24 | 4.0 |
| SD | 6.1 | 1.7 | 1.7 | 1.4 | 1.1 | 1.9 | 1.2 | 2.7 | 0.02 | 0.02 | 1.4 |
| Patients | |||||||||||
| Average | 67.6 | 22 | 25 | 26 | 13 | 13 | 12 | 44 | 0.40 | 0.35 | 11.2 |
| Maximum | 77.0 | 24 | 31 | 29 | 17 | 17 | 16 | 60 | 0.50 | 0.46 | 15.0 |
| Minimum | 59.0 | 19 | 19 | 23 | 9 | 9 | 8 | 23 | 0.30 | 0.25 | 7.0 |
| SD | 4.7 | 1.2 | 2.9 | 1.8 | 2.0 | 2.0 | 2.5 | 8.0 | 0.05 | 0.05 | 2.7 |
| P value | 0.46 | <.005 | <.005 | <.005 | <.005 | <.005 | 0.21 | <.005 | <.005 | <.005 | <.005 |
Note.—AP indicates anteroposterior; Trans, transverse; RC, rostral-caudal; MCP, middle cerebellar peduncle; R, right; L, left; IV Height, vertical dimension of the fourth ventricle measured from the floor of the fourth ventricle to its apex on a midline sagittal image; Ant Horn, maximal width of both anterior horns; Fr. Cereb-Vent Index, ratio of maximal width of both anterior horns to the diameter of inner table of skull along the line of measurement of anterior horn transverse dimension; Evan’s index, ratio of maximal width of both anterior horns to the diameter of inner table of skull at its point of greatest transverse diameter on any image; III Width, width of third ventricle; Note that MCP R and MCP L are the narrowest oblique transverse dimension of the right and left middle cerebellar peduncles measured from an axial image. P values were derived from Student’s t test of control versus patient populations.