title: Arteriovenous shunt measurement during endovascular therapy for cerebrospinal lesions.
abstract: OBJECTIVE
  To determine (a) whether superselective angioscintigraphy with technetium-99m macroaggregated albumin (99mTc-MAA) can be used for the evaluation of arteriovenous shunting in tumors and vascular malformations of the head and spine and (b) whether the amount of microparticles shunted is related to diagnosis, lesion size, or angiographic pattern.
  
  
  METHODS
  Particles of 99mTc-MAA with a calibrated diameter of 25 to 50 microm were delivered intraarterially in feeders of head and spine tumors and vascular malformations in 38 patients. The first estimation of the proportion of particles reaching the lungs was made on-line in the angiography suite using a hand-held lead-shielded detector. Evaluation of the intralesional shunt (pulmonary shunt index, or PSI) was derived from quantitative gamma camera recordings of tumoral and pulmonary activity after the embolization procedure was complete.
  
  
  RESULTS
  The PSI value ranged from 48% to 100% for vascular malformations and vascular tumors (n = 11), 82% to 95% for juvenile angiofibromas (n = 4), 63% to 70% for high-grade gliomas (n = 2), 0% to 50% for renal cell carcinoma metastases (n = 4), 0% to 86% for meningiomas (n = 11), and 0% to 36% for paragangliomas (n = 6). Angiographically, the presence of visible arteriovenous channels was predictive of a high PSI. In contrast, the presence of early venous drainage was associated with a wide PSI range.
  
  
  CONCLUSIONS
  Superselective 99mTc-MAA angioscintigraphy of tumors and vascular malformations of the head and spine is a valuable method for quantifying an intralesional arteriovenous shunt before embolization.
authors.affiliation: Department of Neuroradiology, University of Bern, Inselspital Bern, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Mariani
authors.forename: A R
authors.initials: AR
authors.lastname: Haldemann
authors.forename: G
authors.initials: G
authors.lastname: Schroth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging* / Q000628:therapy; D001165:Arteriovenous Malformations / Q000000981:diagnostic imaging* / Q000628:therapy; D001921:Brain / Q000098:blood supply*; D001932:Brain Neoplasms / Q000098:blood supply* / Q000556:secondary / Q000628:therapy; D002648:Child; D004621:Embolization, Therapeutic / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012039:Regional Blood Flow / Q000502:physiology; D012680:Sensitivity and Specificity; D013120:Spinal Cord Neoplasms / Q000098:blood supply* / Q000556:secondary / Q000628:therapy; D013668:Technetium Tc 99m Aggregated Albumin; D016896:Treatment Outcome
chemical_list: D013668:Technetium Tc 99m Aggregated Albumin