F. Shaikh

High-Dose, Single-Fraction Irradiation Rapidly Reduces Tumor Vasculature and Perfusion in a Xenograft Model of Neuroblastoma

PURPOSE To characterize the effects of high-dose radiation therapy (HDRT) on neuroblastoma tumor vasculature, including the endothelial cell (EC)-pericyte interaction as a potential target for combined treatment with antiangiogenic agents. METHODS AND MATERIALS The vascular effects of radiation therapy were examined in a xenograft model of high-risk neuroblastoma. In vivo 3-dimensional contrast-enhanced ultrasonography (3D-CEUS) imaging and immunohistochemistry (IHC) were performed. RESULTS HDRT significantly reduced tumor blood volume 6 hours after irradiation compared with the lower doses used in conventionally fractionated radiation. There was a 63% decrease in tumor blood volume after 12-Gy radiation compared with a 24% decrease after 2 Gy. Analysis of tumor vasculature by lectin angiography showed a significant loss of small vessel ends at 6 hours. IHC revealed a significant loss of ECs at 6 and 72 hours after HDRT, with an accompanying loss of immature and mature pericytes at 72 hours. CONCLUSIONS HDRT affects tumor vasculature in a manner not observed at lower doses. The main observation was an early reduction in tumor perfusion resulting from a reduction of small vessel ends with a corresponding loss of endothelial cells and pericytes.

Two-Stage Hybrid Repair of a Complex Symptomatic Celiac Aneurysm

We report the case of a novel 2-stage hybrid repair of a complex celiac artery aneurysm. The patient was a 42-year-old man with a proximal celiac artery aneurysm giving rise to distinct right and left hepatic arterial branches. Repair was performed using a staged approach. First, a bifurcated aortohepatic bypass was constructed to the common and left hepatic arteries. After recovering from surgery, he underwent percutaneous embolization of the aneurysm. Completion angiograms demonstrated flow into all celiac branches with successful thrombosis of the aneurysm. At 12-month follow-up, the patient had remained symptom-free with patent bypass grafts and complete aneurysm exclusion. We describe the treatment option we used, which involves repair of a complex celiac aneurysm using a 2-stage, open, endovascular approach.