Size of brain AVMs is measured on the pre-treatment MRI in the 3 views which includes the AVM’s largest diameter.
Measure AVM size in 3 dimensions from pretreatment angiogram in lateral and anteroposterior projections (see Figure above) or from the MRI axial cuts. From these dimensions, a calculation can be made to estimate AVM volume in mL with the ABC/2 formula.
“Reporting Terminology For Brain Arteriovenous Malformation Clinical And Radiographic Features For Use In Clinical Trials”. Stroke 32.6 (2001): 1430-1442. Web.