FIG 1. Calvarial thickening.

A, AROP. Sagittal T1-weighted MR image shows thickening of the calvaria and facial bones. Note hypointensity of skull and cervical vertebra, and cerebellar tonsillar ectopia.

B, ADOP I. Sagittal T1-weighted image shows calvarial thickening and hypointensity, as well as tonsillar ectopia.

C, ADOP II. Sagittal T1-weighted image shows only a moderately thickened calvaria; however, the skull base is more significantly thickened than in the example of ADOP I (B). Compare the small sellar volume with that in ADOP I (B).