Magnetic resonance imaging and proton magnetic resonance spectroscopy of megalencephaly and dilated Virchow-Robin spaces.

Megalencephaly with dilated Virchow-Robin spaces has been suggested to represent a new clinical entity. This report describes two males and a female who have been monitored from pregnancy. The patients manifest a relatively normal psychomotor development with some minor neurologic symptoms such as mild muscle hypotonia and clumsy motor performance. Biochemical and electrophysiologic tests were normal. In the white matter of the brain, a prominent dilatation of the Virchow-Robin spaces with some adjacent signal alterations could be demonstrated by magnetic resonance imaging. Magnetic resonance spectroscopy revealed normal metabolite concentrations in the cortical and deep gray matter and normal-appearing white matter. Affected white matter was characterized by mildly reduced to normal levels of myo-inositol and a decrease of all other metabolites including total N-acetyl moieties, choline-containing compounds, and total creatine. These data indicate that the dilatation of Virchow-Robin spaces reflects an underlying brain pathology causing neuroaxonal damage. Possible differential diagnoses are discussed.