title: Effect of JPEG2000 compression on landmark identification of lateral cephalometric digital radiographs.
abstract: BACKGROUND
  As digital imaging improves and digital cephalometric radiography becomes more prevalent, the need for digital storage space and transmission speed will increase. Compression of the image files is 1 method to overcome transmission overload. However, compression could compromise image quality. The purpose of this study was to determine the range of compression ratios, by using the JPEG2000 standard, within which the identification of landmarks on cephalometric radiographs is not compromised.
  
  
  METHODS
  Ten lateral cephalometric digital images were used. Six raters identified 19 landmarks under controlled viewing conditions. The images included the original uncompressed TIFF image and the JPEG2000 format at 3:1, 12:1, 50:1, and 110:1 compression ratios. The images were randomized and displayed with image processing software. The x and y coordinates of each landmark were recorded.
  
  
  RESULTS
  All compression ratios performed equally well compared with the original images with the exception of A-point and nasion at 110:1 and gonion at 3:1 compression ratios. All landmark identifications were precise with the exception of the maxillary incisal apex and edge at the 12:1 and 50:1 compression ratios, respectively.
  
  
  CONCLUSIONS
  JPEG2000 is a reliable file format that can be implemented in orthodontic practice.
authors.affiliation: Assistant Professor, Department of Care Planning and Restorative Sciences, University of Mississippi College of Dentistry, Schools of Dentistry, University of Mississippi Medical Center, Jackson, Mississippi, and University of Texas Health Science Center at San Antonio, San Antonio, Tex. Electronic address: ahmadoz@yahoo.com.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Abdelkarim
authors.affiliation: Professor, Oral and Maxillofacial Radiology Division, Department of Dental Diagnostic Science, UTHSCSA, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Tex.
authors.forename: Pirkka
authors.initials: P
authors.lastname: Nummikoski
authors.affiliation: Assistant professor, Department of Orthodontics, UTHSCSA, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Tex.
authors.forename: Peter
authors.initials: P
authors.lastname: Gakunga
authors.affiliation: Professor, Departments of Psychiatry and Orthodontics, UTHSCSA, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Tex.
authors.forename: John P
authors.initials: JP
authors.lastname: Hatch
authors.affiliation: Professor, Oral and Maxillofacial Radiology Division, Department of Dental Diagnostic Science, UTHSCSA, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Tex.
authors.forename: S Brent
authors.initials: SB
authors.lastname: Dove
mesh_terms: D002508:Cephalometry; D044962:Data Compression / Q000592:standards*; D006801:Humans; D019252:Radiography, Dental, Digital; D011873:Radiology Information Systems / Q000592:standards; D012984:Software