title: A method for visualizing high-density porous polyethylene (medpor, porex) with computed tomographic scanning.
abstract: BACKGROUND
  Medpor (Porex Surgical, Inc, Newnan, GA) is composed of porous polyethylene and is commonly used in craniofacial reconstruction. When complications such as seroma or abscess formation arise, diagnostic modalities are limited because Medpor is radiolucent on conventional radiologic studies. This poses a problem in situations where imaging is necessary to distinguish the implant from surrounding tissues.
  
  
  OBJECTIVE
  To present a clinically useful method for imaging Medpor with conventional computed tomographic (CT) scanning.
  
  
  METHODS
  Eleven patients (12 total implants) who have undergone reconstructive surgery with Medpor were included in the study. A retrospective review of CT scans done between 1 and 16 months postoperatively was performed using 3 distinct CT window settings. Measurements of implant dimensions and Hounsfield units were recorded and qualitatively assessed.
  
  
  RESULTS
  Of the 3 distinct window settings studied, namely, "bone" (W1100/L450), "soft tissue"; (W500/L50), and "implant" (W800/L200), the implant window proved the most ideal, allowing the investigators to visualize and evaluate Medpor in all cases. Qualitative analysis revealed that Medpor implants were able to be distinguished from surrounding tissue in both the implant and soft tissue windows, with a density falling between that of fat and fluid. In 1 case, Medpor could not be visualized in the soft tissue window, although it could be visualized in the implant window. Quantitative analysis demonstrated a mean (SD) density of -38.7 (7.4) Hounsfield units.
  
  
  CONCLUSIONS
  Medpor may be optimally visualized on conventional CT scans using the implant window settings W800/L200, which can aid in imaging Medpor and diagnosing implant-related complications.
authors.affiliation: New York Presbyterian Hospital, Weill-Cornell Medical Center, New York, New York, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Vendemia
authors.forename: Jerry
authors.initials: J
authors.lastname: Chao
authors.forename: Jana
authors.initials: J
authors.lastname: Ivanidze
authors.forename: Pina
authors.initials: P
authors.lastname: Sanelli
authors.forename: Henry M
authors.initials: HM
authors.lastname: Spinelli
mesh_terms: D000328:Adult; D001672:Biocompatible Materials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019647:Oral Surgical Procedures; D011095:Polyethylenes; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; C084562:Medpor; D011095:Polyethylenes