Abstract

3D Cephalometrics - Can We Go Any Further?

di Gurgurieva Victoria

Background/Objectives: Magnetic resonance imaging (MRI) moved into focus for craniomaxillofacial imaging not only because it is a comparable alternative for CT and CBCT, but also because it avoids ionising radiation. However, MRI is not yet established for cephalometric analysis, since MRI measurements are generally smaller than those obtained via CT and CBCT, which makes them not directly comparable. The aim of the current study is to present an original three-dimensional cephalometric analysis on MRI images based on a transformation of a classical structural analysis. Materials/Methods: A total of 52 MRI images of adult patients with completed skeletal growth were selected from radiological database obtained with conventional MRI system operating at high magnetic field strengths (1.5-3T). All images were standardised for pitch, yaw and roll. Linear measurements were directly performed. A topological individual reference frame was constructed on 19 landmarks and 12 reference lines. Soft tissue (nose, lips and chin) and hard tissue parameters (craniofacial baseline, cranial height, basilar slope, anterior and posterior harmony planes) were analysed. Intra- and interobserver variability were measured and ICC (intraclass correlation coefficient) and Bland-Altman analysis were applied. Results: The topological analysis showed significant study geometric accuracy and high in vivo reproducibility of 3D cephalometric measurements performed on MRI. In topological cephalometry, the different craniofacial structures of a subject are compared in order to provide a facial and mandibular topology. It does not refer to statistical averages, but to individual proportions. Conclusions/Implications: In this study, we demonstrated that accurate and precise 3D cephalometric analysis is feasible using non-ionizing, high-resolution MRI. For the purpose of cephalometric analysis, modern MRI techniques have the potential to overcome the radiation dose dilemma and provide adequate 3D information. Undisputedly, the major drawback of MRI is the high expense of the procedure and trained technicians. With the recent advent of portable low-field MRI (0.055-0.064 T) and procedure duration reduced from 30-45min. to 10-15 min., this soon may become clinical reality. MRI offers the unique possibility to repeat in vivo examinations for 3D cephalometry as often as required. Keywords: 3D imaging; MRI; Topological cephalometry; Cranial morphometry

Obiettivi di apprendimento

Dopo la tua relazione sarai in grado di recognise different modalities of head and cranium imaging and compare their advantages.
Dopo la tua relazione sarai in grado di choose imaging method, most suitable to the Orthodontic treatment objectives.
Dopo la tua relazione sarai in grado di evaluate cephalometric parameters in a non-ionising imaging method.