Usefulness of Diffusion Tensor Imaging in Unexplained Ipsilateral Hemiplegia

Ipsilateral hemiparesis is a rare and challenging sign in clinical neurological practice. Although the etiology of this manifestation is poorly understood, recent studies have attempted to probe the pathomechanism of this sign with advanced radiological techniques. Additional knowledge about the lesion and unraveling the pathomechanisms causing neurological impairments are important to predict the prognosis and clinical course and to aid in rehabilitation. Therefore, we present a case of a patient with a traumatic subdural hematoma on the left hemisphere and left spastic hemiparesis. Using diffusion tensor imaging (DTI), we concluded that the right corticospinal tract injury caused by compression of the cerebral peduncle accounted for the ipsilateral hemiparesis, also known as Kernohan's notch phenomenon. Thus, this case report highlights the usefulness of the newer radiological techniques, such as DTI, to identify the pathomechanisms of neurological presentations.