Preoperative embolization of paragangliomas and angiofibromas. Measurement of intratumoral arteriovenous shunts.

Objective: To determine if technetium Tc 99m-labeled macroaggregated albumin selective angioscintigraphy enables estimation of microparticle-arteriovenous shunt in branchial paragangliomas and nasopharyngeal angiofibromas.

Design: Technetium Tc 99m-labeled macroaggregated albumin particles with calibrated diameters between 25 and 50 microns were administered during selective catheterization of the feeding arteries in 4 branchial paragangliomas (glomus tumors) and 4 nasopharyngeal angiofibromas. Preliminary measures of the activity of the tumor region and of the lungs were obtained in the angiography suite using a hand-held detector. Without changing the position of the microcatheter, definitive embolization was performed. After endovascular treatment, scintigraphy was performed and the pulmonary shunt index was calculated with the use of a gamma camera and a dedicated computer program.

Results: The pulmonary shunt index varied between 0% and 36% for branchial paragangliomas (glomus tumors) and between 82% and 95% for angiofibromas.

Conclusions: Our results provide new evidence that the incidence of microparticle-arteriovenous shunt in nasopharyngeal angiofibromas is much higher than in paragangliomas.