Angel is a 12 year old F/S miniature poodle dog with an acute onset of inability to stand, absent right menace reflex, right sided hemiparesis and extensor rigidity. Her laboratory evaluation was normal and echocardiography revealed mitral and tricuspid regurgitation due to valvular degeneration. MRI revealed an increased signal in the right cerebellar white matter with absent enhancement on T1 weighted images and no mass effect. This finding is classic for a right sided cerebellar infarct.

Magnetic resonance imaging is currently the most sensitive imaging modality available to identify intracranial vascular abnormalities. Abnormalities are visible within hours because of water content changes. An infarct is typically hypointense in T1 and hyperintense in T2 weighted images. Enhancement is variable over time. Gadolinium enhances infarcts because of vascular rupture but does not enhance ischemia or edema. Hemoglobin reacts as a paramagnetic molecule. In cases of hemorrhage, the intensity of the image is secondary to the form of hemoglobin present, its location (intra or extraerythrocytic), and the setting of the machine (variation in TR and TE values).