Secondary degeneration of the substantia nigra and corticospinal tract after hemorrhagic middle cerebral artery infarction: Diffusion-weighted MR findings

Abstract

Middle cerebral artery (MCA) infarction involving the striatum can cause secondary degeneration of the substantia nigra and corticospinal tract. We present a patient with subacute hemorrhagic MCA infarction in whom diffusion-weighted MR images showed high signal intensity in the ipsilateral substantia nigra and corticospinal tract. A corresponding apparent diffusion coefficient map revealed a uniformly decreased signal in the same area. This represents secondary degeneration and should not be mistaken for other pathological conditions, such as a new infarction. © 2002 by Japanese Society for Magnetic Resonance in Medicine.