title: An anatomically validated brachial plexus contouring method for intensity modulated radiation therapy planning.
abstract: OBJECTIVE
  To develop contouring guidelines for the brachial plexus (BP) using anatomically validated cadaver datasets. Magnetic resonance imaging (MRI) and computed tomography (CT) were used to obtain detailed visualizations of the BP region, with the goal of achieving maximal inclusion of the actual BP in a small contoured volume while also accommodating for anatomic variations.
  
  
  METHODS
  CT and MRI were obtained for 8 cadavers positioned for intensity modulated radiation therapy. 3-dimensional reconstructions of soft tissue (from MRI) and bone (from CT) were combined to create 8 separate enhanced CT project files. Dissection of the corresponding cadavers anatomically validated the reconstructions created. Seven enhanced CT project files were then automatically fitted, separately in different regions, to obtain a single dataset of superimposed BP regions that incorporated anatomic variations. From this dataset, improved BP contouring guidelines were developed. These guidelines were then applied to the 7 original CT project files and also to 1 additional file, left out from the superimposing procedure. The percentage of BP inclusion was compared with the published guidelines.
  
  
  RESULTS
  The anatomic validation procedure showed a high level of conformity for the BP regions examined between the 3-dimensional reconstructions generated and the dissected counterparts. Accurate and detailed BP contouring guidelines were developed, which provided corresponding guidance for each level in a clinical dataset. An average margin of 4.7 mm around the anatomically validated BP contour is sufficient to accommodate for anatomic variations. Using the new guidelines, 100% inclusion of the BP was achieved, compared with a mean inclusion of 37.75% when published guidelines were applied.
  
  
  CONCLUSIONS
  Improved guidelines for BP delineation were developed using combined MRI and CT imaging with validation by anatomic dissection.
authors.affiliation: Department of Anatomy, Ghent University, Ghent, Belgium; Department of Radiotherapy, Ghent University, Ghent, Belgium. Electronic address: joris.vandevelde@ugent.be.
authors.forename: Joris
authors.initials: J
authors.lastname: Van de Velde
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Audenaert
authors.forename: Bruno
authors.initials: B
authors.lastname: Speleers
authors.forename: Tom
authors.initials: T
authors.lastname: Vercauteren
authors.forename: Thomas
authors.initials: T
authors.lastname: Mulliez
authors.forename: Pieter
authors.initials: P
authors.lastname: Vandemaele
authors.forename: Eric
authors.initials: E
authors.lastname: Achten
authors.forename: Ingrid
authors.initials: I
authors.lastname: Kerckaert
authors.forename: Katharina
authors.initials: K
authors.lastname: D'Herde
authors.forename: Wilfried
authors.initials: W
authors.lastname: De Neve
authors.forename: Tom
authors.initials: T
authors.lastname: Van Hoof
mesh_terms: D000368:Aged; D001917:Brachial Plexus / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D002102:Cadaver; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008488:Medical Illustration; D056888:Patient Positioning / Q000379:methods; D017410:Practice Guidelines as Topic / Q000592:standards*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods