Arterio-venous Malformations

Cerebral vascular malformations can be classified by histopathology into 4 major types:

1. Arterio-venous malformations (AVMs)
2. Venous angiomas (developmental venous anomalies)
3. Capillary telangiectasias and
4. Cavernous malformations

Arterio-venous malformations (AVMs) are congenital vascular lesions due to dysregulated angiogenesis. They are most often solitary but rarely could be multiple, in which case an underlying syndrome (e.g. hereditary haemorrhagic telangiectasia, cerebrofacial arterio-venous metameric syndrome) is most likely to be present. Patients usually present at 20-40years of age. The most common presentation is headache with parenchymal haemorrhage (accounting for 50% of cases). Twenty five per cent of patients present with seizures and another 25% present with neurological deficits.

The set of CT scans shown here is from a middle-aged woman in her fifties, presenting with recurrent seizures. A non-contrast cranial CT scan performed upon admission (Figures 1 to 5) showed a suspicious looking tortuous structure over the left temporal and occipital lobe . A subsequent contrast cranial CT (Figures 6 to 8) showed an enhancing vascular lesion over the left temporal and occipital region . The feeding arteries, nidus (the core of the AVM which is a tightly packed tangle of abnormal arteries and veins without an intervening capillary bed) and drainage veins are all enhanced after contrast injection. The patient was subsequently started on anticonvulsants and referred to the Neurosurgeons for management.

Treatment options for AVMs include:

1. Endovascular embolization
2. Surgical resection and
3. Focal beam radiation, performed alone or in combination