Fig. 1
From: Phosphomannomutase deficiency (PMM2-CDG): ataxia and cerebellar assessment
Midsagittal vermis relative diameter (MVRD). Legend: Midsagittal vermis relative diameter (MVRD) was calculated using a midsagittal section and measuring total posterior cranial fossa diameter (a linear segment from the posterior commissura to the occipital bone at the foramen magnum) and the largest axial diameter of the cerebellum parallel to the previous linear segment. The fraction (cerebellum diameter/total posterior cranial fossa diameter) is used to express the proportion of both values: \( MVRD=100\frac{a}{A} \). The image represents MVRD calculation of patient 5, with a MVRD result of 49 %