Faculty Bibliography

PURPOSE/OBJECTIVE:To develop and characterize radiopaque embolization microspheres capable of in vivo detection with intraprocedural fluoroscopy and computed tomography (CT) imaging and to evaluate their spatial distribution inside target tissues during and after transcatheter embolization. MATERIALS AND METHODS/METHODS:Polyvinyl alcohol hydrogel microspheres were loaded with Lipiodol and examined for iodine content, stability of loading, and conspicuity with fluoroscopy and CT in vitro. Transcatheter embolization of swine liver and kidney was performed with the radiopaque microspheres and spatial distribution was evaluated with intraprocedural fluoroscopy and CT. Ex vivo evaluation was performed with light microscopy and micro-CT. RESULTS:In vitro analyses demonstrated that radiopaque microspheres could be loaded with sufficient iodine content to be detected with routine fluoroscopy and CT imaging and that such loading was relatively stable. Radiopaque microspheres were visible in vivo with fluoroscopy and CT during transcatheter embolization. CT imaging during embolization procedures demonstrated a dose-dependent relationship in the number and size of visualized embolized arteries. Imaging features of radiopaque microsphere distribution inside target tissues correlated well with ex vivo light microscopic and micro-CT evaluation of microsphere distribution. CONCLUSIONS:Radiopaque embolization microspheres are visualized during transcatheter embolization with routine intraprocedural fluoroscopy and CT. These radiopaque microspheres provided the three-dimensional spatial distribution of embolic material inside target organs during the procedure, and therefore can provide real-time intraprocedural feedback for the interventional radiologist. These microspheres may be useful for demonstrating the influence of material and technical variability in transcatheter embolization in addition to providing intraprocedural identification of tissue at risk of undertreatment.

OBJECTIVE:The perioperative outcomes of open surgical and endovascular repair of intact thoracic aortic aneurysms (TAAs) during the last 3 months of 2005 were compared using a national administrative database. METHODS:The Nationwide Inpatient Sample was used to identify patients undergoing open aneurysm repair (OAR) or endovascular TAA repair (TEVAR) from October 1 to December 31, 2005. Patient demographic data, length of stay, hospital charges, patient disposition, and mortality were examined. Where appropriate, univariate tests of association used the chi(2) test, and multiple logistic regression analysis was used to determine predictors of in-hospital mortality, complications, and discharge status. RESULTS:A total of 1030 patients underwent open TAA repair and 267 underwent TEVAR. There was no significant difference in mortality between OAR and TEVAR (adjusted odds ratio [OR], 1.2; 95% confidence interval [CI], 0.73-2.12), although OAR patients were more likely to have cardiac, respiratory, and hemorrhagic complications. Patients undergoing TEVAR were more likely to be discharged to home (adjusted OR, 6.37; 95% CI, 2.93-13.70) and had a decreased length of stay (5.7 days vs 9.9 days; P = .0015). The differences in hospital charges and costs were not significant. CONCLUSION/CONCLUSIONS:Although further study is warranted, this study of a national sample suggests that endovascular TAA repair is safe in the short-term, associated with fewer cardiac, respiratory, and hemorrhagic complications, and requires a shorter hospital stay.

This retrospective study investigates the potential of image analysis to quantify for the presence and extent of pulmonary hypertension secondary to sickle cell disease (SCD). A combination of fast marching and geodesic active contours level sets were employed to segment the pulmonary artery from smoothed CT-Angiography images from 16 SCD patients and 16 matching controls. An algorithm based on fast marching methods was used to compute the centerline of the segmented arteries to measure automatically the diameters of the pulmonary trunk and first branches of the pulmonary arteries. Results show that the pulmonary trunk and arterial branches are significantly larger in diameter in SCD patients as compared to controls (p-values of 0.002 for trunk and 0.0003 for branches). For validation, the results were compared with manually measured values and did not demonstrate significant difference (mean p-values 0.71). CT with image processing shows great potential as a surrogate indicator of pulmonary hemodynamics or response to therapy, which could be an important tool for drug discovery and noninvasive clinical surveillance.