(1) The vascular component of the cerebral arteriovenous malformation exhibits a signal-free flow-void vascular shadow in a massed, reticular distribution. The blood supply arteries show low or no signal on T1 and T2-weighted images due to the flow-void phenomenon. The draining veins show low signal on T1-weighted images and high signal on T2-weighted images due to slow flow. Calcification of the vessel appears as a low or no signal dark area. The thrombus in arteriovenous malformation shows low signal interspersed with iso-signal or high signal interspersed with high signal within high signal and low signal in both T1 and T2-weighted images. (2) Hematoma formed by bleeding from arteriovenous malformation shows similar changes in T1 and T2-weighted images and other causes of hematoma. In the subacute stage, the hematoma is high signal on both T1 and T2-weighted images, and with time, the hematoma gradually changes to iso- or low-signal on T1-weighted images and remains high signal on T2-weighted images.