How does angiodysplasia appear at angiography?
Angiodysplasia appears as a vascular tuft or tangle of vessels resulting from a local mass of irregular vessels, best visualized in the arterial phase. It demonstrates early and intensely filling veins because of direct communication of the artery to the veins without intervening capillaries. It typically shows persistent opacification beyond the normal venous phase (slowly emptying vein) likely from venous tortuosity (ectasia). At angiography, bleeding angiodysplasia shows extravasation of blood in which the blood is seen to actively pool near the vascular tuft. Angiodysplasias bleed only intermittently, however, and demonstrate extravasation of contrast in only approximately 10% of cases at angiography.