Abstract
Objectives and Methods The Artery of Percheron (AOP) is an uncommon anatomical variant whereby the paramedian arteries supplying both thalami arise from a single common trunk from either posterior cerebral artery P1 segment. We describe the case of a 75 year old female who was diagnosed with an AOP stroke after presenting with the triad of altered level of consciousness, memory deficits and vertical gaze palsies.
Results A CT brain and angiogram showed a right P1 segment occlusion. The CT perfusion scan showed a focal area of mildly increased time to peak within the left PCA territory without corresponding cerebral blood flow or volume abnormality. Subsequent MRI revealed DWI hyperintensity with corresponding ADC hypointensity in the bilateral anteromedial thalamus with corresponding T2 FLAIR hyperintensity consistent with an AOP stroke.
Conclusion Knowledge of AOP stroke is important as it is a differential for patients presenting with an abrupt reduction in their level of consciousness. The syndrome is a diagnostic challenge and overlooking it can lead to delays in the provision of hyperacute therapies. CT perfusion is a low spatial resolution study with poor sensitivity for strokes of the deep grey nuclei as these tend to be small. AOP stroke is a mimicker of rostral brainstem stroke (a.k.a ‘top of the basilar syndrome’). Therefore if basilar artery patency is observed in a patient despite suggestive symptoms, AOP stroke should be considered. Thalamic perforating branches are rarely visualised on CT angiography because of their narrow diameter therefore an AOP stroke must be inferred.
