Dynamic computed tomography in the evaluation of vascular lung lesions

Rapid sequence (dynamic) computed tomography (CT) following the bolus injection of contrast material into a peripheral vein allows a differentiation of vascular and nonvascular lung lesions. The use of time-density curves plotting the changing CT number over time also allows pulmonary arterial supply of lung lesions to be distinguished from systemic (aortic) supply. Of four patients suspected of having pulmonary arteriovenous fistula, two were shown to have nonvascular lesions and two were shown to have vascular malformations by using dynamic CT. In one patient, a pulmonary vein varix was confirmed by using CT. In two patients, systemic arterial supply to abnormal lung was correctly diagnosed with CT; this finding was also shown in both patients by using arteriography. In some cases dynamic CT obviates arteriography; in others, it helps direct further evaluation.