Abstract
Objectives and Methods Intracranial arterial dolichoectasia is a dilative vasculopathy associated with an increased risk of stroke. There is limited haemodynamic assessment of dolichoectasia using cerebral perfusion imaging. We describe a 64-year-old male who presented with clinical features consistent with right middle cerebral artery (MCA) stroke but multimodal CT demonstrated a large volume of persistent hypoperfusion within the posterior circulation in the setting of severe vertebrobasilar dolichoectasia.
Results A CT angiogram showed right internal carotid artery occlusion (type I) and severe vertebrobasilar dolichoectasia based on Smoker criteria. CT perfusion demonstrated 113 ml of time-to-maximum (Tmax) >6 second delay in the posterior fossa with a 5 ml of ischaemic core in the right hemisphere. CT perfusion parameter maps showed a normal mean transit time (MTT). Thrombolysis was administered based on clinical suspicion of a right MCA stroke, which was confirmed on 24-hour MRI. MR perfusion revealed persistent 94 ml of Tmax >6 second delay involving the posterior fossa without MTT changes.
Conclusion Intracranial arterial dolichoectasia of the posterior circulation can result in asymptomatic persistent hypoperfusion, and isolated prolongation of Tmax without MTT changes can be demonstrated on perfusion imaging. This case illustrates that perfusion abnormalities of asymptomatic dolichoectasia can mimic acute ischaemic stroke and careful examination of perfusion parameter maps is essential to ensure accurate interpretation of cerebral perfusion imaging. The clinical significance of such perfusion abnormalities is uncertain.
