MRI features of basilar artery dolichoectasia with dissection. The patient's symptoms are due to the compression of the right side of the brainstem by the enlarged tortuous basilar artery resulting in pontine ischaemia, and the compression of the cervicomedullary junction by the posteriorly arched right vertebral artery. The enlarged basilar artery also extends upwards indenting the floor of the third ventricle, with a high tip/bifurcation. 

It is a rare type for intracranial arterial dissection. A more serious presentation for this condition is spontaneous subarachnoid haemorrhage ¹.