Hereditary hemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber syndrome, is a rare disorder that is closely linked to the development of pulmonary arteriovenous malformations (PAVM). Diagnosis can be based on clinical signs such as upper respiratory tract changes or recurrent hemorrhagic events. Nevertheless, pulmonary involvement, a prognostic factor, may remain undetected. In the three HTT cases with PAVM we report, the following diagnostic information was obtained non-invasively: shunt fraction measurements (breathing 100% oxygen), echocardiographic contrast studies, and three-dimensional helical computed tomographs. Arteriography demonstrated a single PAVM in one case and the patient underwent successful coil embolization, with clinical and functional improvement.