MR angiographic diagnosis of recanalization in a thrombosed pulmonary arteriovenous malformation.

Pulmonary arteriovenous malformation (PAVM) results from an anomalous communication between a pulmonary artery and vein and may lead to life-threatening hemoptysis. Pulmonary angiography is the standard diagnostic technique but may be falsely negative in the unusual instance of a thrombosed PAVM. We report a patient with a thrombosed PAVM in which the initial pulmonary angiogram incorrectly suggested pulmonary embolism. A subsequent magnetic resonance (MR) angiogram demonstrated recanalization of the PAVM, thus establishing the true nature of the lesion and leading to appropriate intervention.