Common and rare arterial collateral pathways are reviewed by 3D volume-rendered CT images. Visceral and lower extremity arterial embryology is reviewed.

Twenty-two patients with malignant biliary obstruction and 21 patients with suspected obstruction of biliary-enteric anastomoses were evaluated over a 12-month period with magnetic resonance (MR) cholangiography and cross-sectional MR imaging. In patients with malignant obstruction, MR cholangiography helped accurately determine the status of the biliary ductal system by identifying the exact location and extent of the obstruction and the severity of duct dilatation. In so doing, MR cholangiography helped determine whether percutaneous transhepatic cholangiography with antegrade stent placement or retrograde cholangiography with stent placement constituted the more suitable treatment. Cross-sectional MR imaging was necessary to identify the organ of tumor origin, define the tumor margins, and determine the stage of disease. This information helped evaluate the appropriateness of curative surgical therapy versus palliative drainage procedures. In patients with biliary-enteric anastomoses, MR cholangiography clearly depicted the site of the anastomosis and demonstrated the status of the intrahepatic ducts, thereby helping determine which patients would benefit from undergoing antegrade duct cannulation with a drainage procedure or perhaps balloon dilation. In some of these patients, MR cholangiography was sufficient to help plan therapeutic intervention. MR cholangiography also demonstrates the presence and size of biliary stones and associated findings such as intraductal tumor growth. In addition, MR cholangiography may obviate retrograde cholangiography, which can be technically difficult to perform.

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Despite the promising results from the placement of covered or uncovered self-expandable metallic stent (SEMS) as a nonsurgical therapeutic option for the malignant gastric outlet obstruction (GOO), the long patency of the stent is still limited because of stent-induced tissue hyperplasia. Here, a local heat treatment using a nanofunctionalized SEMS is proposed for suppressing stent-induced tissue hyperplasia during GOO treatment. Highly efficient photothermal gold nanoparticle (GNP) transducer-coated SEMSs (GNP-SEMSs) were prepared for local heat treatment in rat gastric outlet. The in vivo heating temperature in rat gastric outlet model was evaluated and compared with in vitro heating temperature. Three groups of our developed 45 rat gastric outlet models were used: group A, noncoated SEMS only; group B, GNP-SEMS plus local heating; and group C, GNP-SEMS only to investigate in vivo efficacy of GNP-SEMS mediated local heating. Ten rats per group were sacrificed for 4 weeks, and five rats per group were sacrificed immediately after local heat treatment. The in vivo heating temperature was found to be 10.8% lower than the in vitro heating temperatures. GNP-SEMSs were successfully placed through a percutaneous approach into the rat gastric outlet (n = 45). The therapeutic effects of GNP-SEMS were assessed by histologic examination including hematoxylin-eosin, Masson trichrome, immunohistochemistry (TUNEL and CD31), and immunofluorescence (Ki67), and the results showed significant prevention of tissue hyperplasia following stent placement without adjacent gastrointestinal tissue damage. GNP-SEMS-mediated local heating could be an alternative therapeutic option for the suppression of tissue hyperplasia following stent placement in benign and malignant GOOs.