title: Development of hepatic pseudotumors for image-guided interventional and surgical research in a large animal model.
abstract: OBJECTIVE
  Real-time image guidance and navigation have become increasingly important in an era of minimally invasive interventional and surgical procedures in the liver. To develop, test, and implement tools for real-time image guidance, the authors sought to create an in vivo tumor mimic with realistic imaging and treatment capabilities.
  
  
  METHODS
  Hepatic pseudotumors were created by injecting 1-2 mL of alginate (a hydrocolloid) directly into the liver parenchyma in eight live pigs and two dog cadavers. Tumors were imaged by B-mode ultrasound (US), US elasticity imaging, multi-detector row computed tomography (CT), CT fluoroscopy, and magnetic resonance (MR) imaging to assess imaging capabilities. Procedures performed with the alginate pseudotumors included radiofrequency (RF) ablation and robotic needle guidance.
  
  
  RESULTS
  Twenty-four hepatic pseudotumors were created, ranging in size from 10 mm to 28 mm at an average depth of 6 mm. Average time of preparation and insertion was 3 minutes. All tumors were palpable under the surface of the liver and were easily visible on B-mode US, US elasticity imaging, CT, and MR imaging. Tumors were successfully "treated" with RF ablation, and gross examination of the liver showed good encompassment of the tumor by the zone of thermal coagulation. In addition, the pseudotumors allowed for easy introduction of various types of needles, including RF ablation probes and experimental steerable needles.
  
  
  CONCLUSIONS
  Alginate pseudotumors can easily be imaged and allow for different procedures to be performed. This model can be used for various research purposes.
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
authors.forename: Mark G
authors.initials: MG
authors.lastname: van Vledder
authors.forename: Lia
authors.initials: L
authors.lastname: Assumpcao
authors.forename: Sanjay
authors.initials: S
authors.lastname: Munireddy
authors.forename: Kartik
authors.initials: K
authors.lastname: Sehgal
authors.forename: Emad M
authors.initials: EM
authors.lastname: Boctor
authors.forename: Michael A
authors.initials: MA
authors.lastname: Choti
mesh_terms: D000464:Alginates; D000818:Animals; D017115:Catheter Ablation; D004195:Disease Models, Animal; D004285:Dogs; D054459:Elasticity Imaging Techniques; D005260:Female; D020723:Glucuronic Acid; D006104:Granuloma, Plasma Cell / Q000139:chemically induced / Q000175:diagnosis / Q000601:surgery*; D006603:Hexuronic Acids; D008107:Liver Diseases / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D013552:Swine; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid