Internal carotid artery dissection causes hypoglossal nerve palsy: CT, MRI, and angiographic findings.

A case of unilateral XIIth nerve palsy due to the dissection of the internal carotid artery is reported. The clinical and radiological features are described. In this patient, cranial nerve palsy is probably the result of compression by an enlarging carotid artery due to mural hematoma. Diagnosis is discussed with emphasis on magnetic resonance imaging findings. Magnetic resonance imaging is also useful for follow-up of arterial lesions.