Hypodense artery sign in cerebral fat embolism

摘要

A female patient in her mid 70s underwent aortic valve replacement and single-vessel coronary artery bypass grafting, but after awakening from anaesthesia was found to have left-sided weakness. She had a history of severe aortic stenosis, hypertension, diabetes mellitus and hyperlipidaemia. On examination, there was right gaze deviation and a dense left hemiplegia. Non-contrasfed CT scan of head and cerebral angiography showed a 1.5 cm hypodense filling defect in the distal Ml segment of the right middle cerebral artery, measuring -80 Hounsfield units, consistent with fat density (figure 1A,B). There were also early ischaemic changes in the right middle cerebral artery territory.