Angiographic evaluation and management of acute gastrointestinal hemorrhage

Although most cases of acute nonvariceal gastrointestinal hemorrhage either spontaneously resolve or respond to medical management or endoscopic treatment,there are still a significant number of patients who require emergency angiography and transcatheter treatment.Evaluation with noninvasive imaging such as nuclear scintigraphy or computed tomography may localize the bleeding source and/or confirm active hemorrhage prior to angiography.Any angiographic evaluation should begin with selective catheterization of the artery supplying the most likely site of bleeding,as determined by the available clinical,endoscopic and imaging data.If a hemorrhage source is identified,superselective catheterization followed by transcatheter microcoil embolization is usually the most effective means of successfully controlling hemorrhage while minimizing potential complications.This is now wellrecognized as a viable and safe alternative to emergency surgery.In selected situations transcatheter intra-arterial infusion of vasopressin may also be useful in controlling acute gastrointestinal bleeding.One must be aware of the various side effects and potential complications associated with this treatment,however,and recognize the high re-bleeding rate.In this article we review the current role of angiography,transcatheter arterial embolization and infusion therapy in the evaluation and management of nonvariceal gastrointestinal hemorrhage.

Angiographic and volumetric effects of mammalian target of rapamycin inhibitors on angiomyolipomas in tuberous sclerosis

AIM: To investigate the angiographic and volumetric effects of mammalian target of rapamycin(m TOR) inhibitors on angiomyolipomas(AMLs) in a case series of patients with tuberous sclerosis complex.METHODS: All patients who underwent catheter angiography prior to and following m TOR inhibitor therapy(n = 3) were evaluated. All cross-sectional imaging studies were analyzed with three-dimensional volumetrics, and tumor volume curves for all three tissue compartments(soft tissue, vascular, and fat) were generated. Segmentation analysis tools were used to automatically create a region of interest(ROI) circumscribing the AML. On magnetic resonance images, the "fat only" map calculated from the in- and opposed-phase gradient recalled echo sequences was used to quantify fat volume within tumors. Tumor vascularity was measured by applying a thresholding toolwithin the ROI on post-contrast subtraction images. On computed tomography images, volume histogram analysis of Hounsfield unit was performed to quantify tumor tissue composition. The angiography procedures were also reviewed, and tumor vascularity based on pre-embolization angiography was characterized in a semi-quantitative manner. RESULTS: Patient 1 presented at the age of 15 with a 6.8 cm right lower pole AML and a 4.0 cm right upper pole AML. Embolization was performed of both tumors, and after a few years of size control, the tumors began to grow, and the patient was initiated on m TOR inhibitor therapy. There was an immediate reduction in the size of both lesions. The patient then underwent repeat embolization and discontinuation of m TOR inhibition, after which point there was a substantial regrowth in both tumors across all tissue compartments. Patient 2 presented at the age of 18 with a right renal AML. Following a brief period of tumor reduction after embolization, she was initiated on m TOR inhibitor therapy, with successful reduction in tumor size across all tissue compartments. As with patient 1, however, there was immediate rebound growth following discontinuation of inhibitor therapy, without sustained control despite repeat embolization. patient 3 presented at the age of 5 with a left renal AML and underwent two embolization procedures without lasting effect prior to starting m TOR inhibition. As with patients 1 and 2, following discontinuation of therapy, there was immediate rebound growth of the tumor. Repeat embolization, however, was notable for a substantial reduction in intratumoral aneurysms and vascularity.CONCLUSION: AML volume reduction as well as posttreatment rebound growth due to m TOR inhibitors involves all three tissue components of the tumor.