Ependymal dot-dash sign

The ependymal dot-dash sign has been described as an early MRI imaging feature of multiple sclerosis before other more florid white matter changes (e.g. Dawson's fingers) become evident . It has also been suggested as a feature that can be used to distinguish multiple sclerosis from neuromyelitis optica (NMO) which less frequently demonstrate this sign .


The dot-dash sign represents early perivenular involvement of the ependyma of the lateral ventricles .

Radiographic features


The sign is best seen on sagittal FLAIR along the inferior surface of the corpus callosum and roof of the lateral ventricle bodies. It is seen as tiny (~1 mm) dots of high signal along the ependymal surface that may coalesce into short dashes . It presence has been reported as being very sensitive (>95%) and moderately specific (>70%) in younger individuals (<50 years of age) . In older patients, who have periventricular high T2 signal due to ischemic change, this sign is less sensitive and specific .