title: Fractal dimension analysis of malignant and benign endobronchial ultrasound nodes.
abstract: BACKGROUND
  Endobronchial ultrasonography (EBUS) has been applied as a routine procedure for the diagnostic of hiliar and mediastinal nodes. The authors assessed the relationship between the echographic appearance of mediastinal nodes, based on endobronchial ultrasound images, and the likelihood of malignancy.
  
  
  METHODS
  The images of twelve malignant and eleven benign nodes were evaluated. A previous processing method was applied to improve the quality of the images and to enhance the details. Texture and morphology parameters analyzed were: the image texture of the echographies and a fractal dimension that expressed the relationship between area and perimeter of the structures that appear in the image, and characterizes the convoluted inner structure of the hiliar and mediastinal nodes.
  
  
  RESULTS
  Processed images showed that relationship between log perimeter and log area of hilar nodes was lineal (i.e. perimeter vs. area follow a power law). Fractal dimension was lower in the malignant nodes compared with non-malignant nodes (1.47(0.09), 1.53(0.10) mean(SD), Mann-Whitney U test p < 0.05)).
  
  
  CONCLUSIONS
  Fractal dimension of ultrasonographic images of mediastinal nodes obtained through endobronchial ultrasound differ in malignant nodes from non-malignant. This parameter could differentiate malignat and non-malignat mediastinic and hiliar nodes.
authors.affiliation: Pulmonology Department, Hospital Universitari Germans Trias Pujol, Planta 8, Carretera del Canyet s/n, 08916, Badalona, Spain. jafiz@msn.com.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Fiz
authors.forename: Enrique
authors.initials: E
authors.lastname: Monte-Moreno
authors.forename: Felipe
authors.initials: F
authors.lastname: Andreo
authors.forename: Santiago José
authors.initials: SJ
authors.lastname: Auteri
authors.forename: José
authors.initials: J
authors.lastname: Sanz-Santos
authors.forename: Pere
authors.initials: P
authors.lastname: Serra
authors.forename: Gloria
authors.initials: G
authors.lastname: Bonet
authors.forename: Eva
authors.initials: E
authors.lastname: Castellà
authors.forename: Juan Ruiz
authors.initials: JR
authors.lastname: Manzano
mesh_terms: D001999:Bronchoscopy / Q000379:methods*; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging; D017709:Fractals; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008198:Lymph Nodes / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D055641:Mathematical Concepts; D064847:Multimodal Imaging; D014463:Ultrasonography