MR imaging of ventriculomegaly--a qualitative and quantitative comparison of communicating hydrocephalus, central atrophy, and normal studies.

Both communicating hydrocephalus and central atrophy cause ventricular dilatation. However, patients with hydrocephalus may require treatment. The aim of this study was to assess qualitatively and quantitatively the efficacy of MR imaging in the differentiation of communicating hydrocephalus from central atrophy. The midsagittal T1-weighted MR images of 33 patients with communicating hydrocephalus, 31 patients with central atrophy, and 23 normal subjects were evaluated qualitatively and quantitatively. This included configuration of the aqueduct; area of the septum pellucidum, third ventricle, and fourth ventricle; and morphology of the corpus callosum. Distal dilatation of the aqueduct was detected in 33.3% of patients with communicating hydrocephalus and in none of those with central atrophy. The corpus callosum was elevated in patients with communicating hydrocephalus when compared with that in patients with central atrophy. In conclusion, an analysis of midsagittal T1-weighted images has identified useful qualitative and quantitative criteria in the differentiation of communicating hydrocephalus from central atrophy. The configuration of the aqueduct with funneling at the fourth ventricular end strongly suggests the presence of communicating hydrocephalus rather than central atrophy alone.