Abstract

Introduction: Cephalometric analysis is a cornerstone of orthodontic diagnosis, yet much information is lost when 3-dimensional structures are assessed with 2-dimensional methods. CBCT offers 3-dimensional imaging but at the cost of higher levels of ionizing radiation. Magnetic resonance imaging provides 3-dimensional imaging without ionizing radiation and additionally imparts visualization of soft tissue structures. Prior to employing MR images for cephalometric analysis, reliability of landmark identification must be assessed. The purpose of this study was to evaluate intra- and interobserver reliability in 3-dimensional landmark identification using MR images.

Materials and Methods: Fifteen cranial MR images (3.0 T, MP-RAGE) from subjects between the ages of 22-30 years were obtained for the study. Three observers independently repeated 3 times the identification of 30 cephalometric landmarks using Dolphin software (version 10.5). Intraclass correlation and F-tests were calculated independently for each observer and for each identification session to estimate intra- and interobserver reliability.

Results: ICC was > 0.9 for more than 95% of intraobserver coordinates for two of the three observers, with the remaining observer at 66.7%. ICC was > 0.9 for more than 80% of interobserver coordinates for two of the three sessions with the remaining session at 71.1%. Only one observer showed ICC < 0.45 for intraobserver coordinates (4.4%). Interobserver coordinates with ICC < 0.9 could be attributed to one observer for all but two landmarks.

Conclusions: Excellent intra- and interobserver reliability of landmark identification can be achieved using MR images but observers must be carefully trained and calibrated. Landmarks require precise definitions in all 3 planes of space and should preferably not be located at sites where magnetic resonance imaging is inherently insensitive.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Dentistry

School

Graduate Studies

First Advisor

V. Leroy Leggitt

Second Advisor

Khaled Bahjri

Third Advisor

Joseph Caruso

Fourth Advisor

James Farrage

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2009

Date (Title Page)

9-2009

Language

English

Library of Congress/MESH Subject Headings

Orthodontics, Interceptive; Cephalometry -- methods; Cephalometry -- statistics and numerical data; Diagnostic Imaging -- method; . Cone-Beam Computed Tomography; Magnetic Resonance Imaging; Imaging, Three-Dimensional; Radiographic Image Enhancement; Image Interpretation, Computer-Assisted; Observer Variation; Comparative Study; Reproducibility of Results

Type

Thesis

Page Count

xi; 90

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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