Cerebral Ventriculomegaly in Myotonic Dystrophy Type 1: Normal Pressure Hydrocephalus-like Appearances on Magnetic Resonance Imaging

Abstract Background: Cerebral ventriculomegaly is an abnormal feature characteristic of myotonic dystrophy type 1 (DM1). This retrospective study investigated the morphologic changes accompanied by ventriculomegaly in DM1 on brain MRI.Methods: One hundred and twelve adult patients with DM1 and 50 sex- and age-matched controls were assessed. The imaging characteristics for evaluations included the z-Evans Index (ventriculomegaly), callosal angle (CA), enlarged perivascular spaces in the centrum semiovale (CS-EPVS), temporo-polar white matter lesion (WML) on 3D fluid-attenuated inversion recovery (FLAIR), disproportionately enlarged subarachnoid-space hydrocephalus (DESH), and pathological brain atrophy. The “z-Evans Index” was defined as the maximum z-axial length of the frontal horns to the maximum cranial z-axial length. To determine the imaging characteristics and genetic information (CTG repeat numbers) that were associated with the z-Evans Index, we used multivariate logistic regression analyses.Results: The z-Evans Index was significantly larger in the patients than in the controls (0.30±0.05 vs. 0.24 ± 0.02; p < 0.01). The multivariate logistic regression analyses showed that the z-Evans Index was independently associated with the patient age (p <0.05), CA (p < 0.01), Sylvian fissure dilation (p < 0.01), and pathological brain atrophy (p < 0.01) but not with CTG repeat numbers, CS-EPVS, or temporo-polar WML. Of the 34 patients older than 49 years, 7 (20.6%) were considered to have DESH.Conclusions: Our MRI study revealed a normal pressure hydrocephalus (NPH)-like appearance as a morphologic finding accompanied by ventriculomegaly in DM1 that tends to occur in elderly patients.