Is arterial spin labelling necessarily low perfusion for cavernous sinus venous malformation? A case of hyperperfusion cavernous sinus venous malformation.

Generally, due to the complexity of the skull base structures, it is difficult to differentiate cavernous vascular malformation and meningioma in the cavernous sinus area using conventional imaging studies. Cavernous sinus venous malformation are characterized by increased capillary masses without a direct arterial supply, typically leading to low perfusion. On the other hand, meningiomas receive arterial blood supply to the tumour and often exhibit high perfusion. So, arterial spin labelling (ASL) can be helpful in distinguishing between the 2 tumour types. However, in our specific case of a cavernous sinus venous malformation, the ASL imaging showed hyperperfusion. Further analysis revealed that this hyperperfusion on ASL can occur when cavernous sinus venous malformation is associated with arteriovenous fistula malformation.