title: The effect of region of interest variations on morphologic operations data and gray-level values extracted from digitized dental radiographs.
abstract: OBJECTIVE
  To determine the correlations among morphologic operations (MO) values and the correlations among gray-level values for regions of interest (ROIs) placed at various locations on digital images of alveolar bone for 45 patients.
  
  
  METHODS
  As part of a larger study, up to 7 vertical bite-wing radiographs were taken and digitized for each of 45 patients. Sets of 2 rectangular ROIs were placed on the digitized images of interdental alveolar bone at 4 locations for each patient. The ROIs (1 crestal and 1 apical) were placed between second premolars and first molars in all 4 dental quadrants. Gray-level values were measured, and MO analysis was performed on each ROI. Descriptive statistics were calculated and correlations determined.
  
  
  RESULTS
  Paired correlations (such as apical vs crestal, left vs right, maxillary apical vs mandibular apical) of MO values were weak (r = 0.01-0.21), but corresponding correlations for gray-level values were relatively strong (r = 0. 60-0.92).
  
  
  CONCLUSIONS
  MO values varied with ROI location considerably more than did gray-level values. Additionally, ROI size and shape apparently affected MO data. Accurate placement and documentation of ROIs appear to be critical considerations in analyses that use MOs.
authors.affiliation: Department of Oral Diagnosis and Patient Services, The Medical College of Georgia, School of Dentistry, Augusta 30912-1241, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Shrout
authors.forename: B A
authors.initials: BA
authors.lastname: Farley
authors.forename: S M
authors.initials: SM
authors.lastname: Patt
authors.forename: B J
authors.initials: BJ
authors.lastname: Potter
authors.forename: C F
authors.initials: CF
authors.lastname: Hildebolt
authors.forename: T K
authors.initials: TK
authors.lastname: Pilgram
authors.forename: N
authors.initials: N
authors.lastname: Yokoyama-Crothers
authors.forename: M
authors.initials: M
authors.lastname: Dotson
authors.forename: J
authors.initials: J
authors.lastname: Hauser
authors.forename: S
authors.initials: S
authors.lastname: Cohen
authors.forename: E
authors.initials: E
authors.lastname: Kardaris
authors.forename: P
authors.initials: P
authors.lastname: Hanes
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging* / Q000473:pathology*; D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D011856:Radiographic Image Enhancement; D016300:Radiography, Bitewing / Q000379:methods*; D019252:Radiography, Dental, Digital / Q000379:methods*; D018709:Statistics, Nonparametric