Wall enhancement of leaking polytetrafluoroethylene grafts: a new CT sign.

Perigraft seroma is a rare complication of synthetic vascular grafts. We describe a new sign observed in two children who underwent computed tomography of the chest for further evaluation of seromas complicating modified Blalock-Taussig procedures in which a polytetrafluoroethylene graft was used. In both patients contrast enhancement of the wall of the leaking graft was demonstrated on delayed imaging. One patient had bilateral grafts, and the enhancement was only demonstrated in the wall of the leaking graft. We discuss the possible mechanism of this finding and propose that this sign may be further evidence of abnormal graft permeability.