Identification of an anteriorly displaced meniscus in vitro by means of three-dimensional image reconstructions

Computerized three-dimensional magnetic resonance imaging reconstructions of temporomandibular joints for both a model and patients with temporomandibular pain dysfunction

The aim of this study was to assess computerized three-dimensional reconstruction of magnetic resonance images generated of a temporomandibular joint model and the temporomandibular joints of five patients with varying degrees of temporomandibular joint pain and dysfunction. The three-dimensional image reconstruction of an artificial temporomandibular joint model, consisting of a human dried skull and synthetic disk, was used to test the accuracy and reproducibility of the three-dimensional technique. It was found that computerized three-dimensional reconstruction improved the display format of magnetic resonance imaging by enabling multiple two-dimensional images in shades of grey to be viewed as one three-dimensional image with anatomic structures colored as desired. Further, by rotating this image, the anatomic relationships of the temporomandibular joint could be seen from any viewpoint. Volume measurements showed accuracy and reproducibility by independent operators. Computerized three-dimensional reconstruction was applied to the magnetic resonance images obtained from patients. They were used to assess magnetic resonance imaging technique and its applications for interpreting the clinical findings. Disk position, as revealed by the three-dimensional images, was found to correspond with the clinical assessment, except in two instances when the original, right-sided, magnetic resonance imaging was unclear. Three-dimensional reconstruction was simple to apply, required no patient involvement, and made multiple magnetic resonance images easier to interpret.

Positional changes of the mandibular condyle assessed by three-dimensional computed tomography

This investigation was designed to test the validity and reliability of three-dimensional computed tomography (3-D CT) for quantification of positional changes of the condyle in a laboratory model. The model consisted of a mounted dried human skull and a mandibular condyle attached to a micromanipulator. Controlled changes in condylar position were made and the condyle/fossa was imaged. Positional changes were measured by triangulation methods based on specific 3-D CT landmarks. The data were analyzed using descriptive statistics, analyses of variance to evaluate the sources of variability, and linear contrasts to evaluate the differences between observed and expected values. The results indicated that selection of appropriate anatomic landmarks for assessment of movement influences technique accuracy. The data also indicate that 3-D CT is most accurate in detecting inferior condylar movements. Lateral and posterior movements were assessed with less accuracy than the inferior positional changes. The clinical significance of these differences has yet to be determined.

Three-dimensional visualization of the temporomandibular joint: a computerized multisectional autopsy study of disc position and configuration

To demonstrate disc position and disc configuration of the temporomandibular joint, three-dimensional multisectional computer reconstructions were made of 20 autopsy specimens (11 female, 9 male; mean age, 40.4 years). The presence of a distinct occlusion was the only criterion for selection. Normal disc position was found in 13 joints, partial anterior disc position was found in 5 joints, and complete anterior disc position was seen in 2 joints. Fifteen joints had biconcave disc configuration and 5 joints had deformed discs. Considering the high incidence of disc position deviating from the normal superior position, it is suggested that in some cases a so-called abnormal disc position can be regarded as within the limits of anatomic and physiological variability.

Three-dimensional computed tomography for maxillofacial surgery: report of cases

Methods of three-dimensional analysis of axial computed tomographic images have recently been described. Mostly, reports have concentrated on applications relative to congenital deformities. In this report, one method of three- dimensional reformatting is reviewed. Images formed by this method have solid surface appearance and can be color enhanced and manipulated to isolate anatomic structures of interest. The program allows mathematical quantitation of tissue densities, volumes, and distances. Furthermore, models and implants can be easily made using the programs CAD-CAM ability. These images and models can be generated from data obtained on the most common CT units without any modifications. This report emphasizes maxillofacial applications other than those previously reported in the surgical and radiological literature.