Letter from the Guest Editor

Article Outline

• Copyright

I was contacted after the 2004 RSNA meeting by Dr. Joel Swartz who invited me to be guest editor of this issue of the Seminars in Ultrasound, CT And MRI. Because there have been many valuable contributions to the literature by a number of internationally recognized experts on the imaging manifestations of temporo-mandibular joint (TMJ) dysfunction, I had great difficulty deciding whom I should ask to participate. I had to choose from anatomists, dentists, surgeons and radiologists, all of whom have presented relevant manuscripts or innovative reports in the last several years. Fortunately, I believe I was able to recruit an exceptional group of qualified authors.

Over the last several decades, a number of imaging techniques have been developed and refined to expand the role of the radiologist in the evaluation of diseases affecting TMJ. Prior to MRI, arthrography was widely accepted as preferred imaging technique for evaluating TMJ internal derangement because it provided high diagnostic accuracy in the evaluation of the position and diagnosis of perforation of the disk. In the 1980’s, CT was developed which allowed the depiction of osseous abnormalities, but was limited in the evaluation of soft tissue anatomy. Eventually, arthrography and CT were surpassed by MRI. The latter grew in popularity because it is noninvasive, does not use ionizing radiation and allows excellent multiplanar visualization of all TMJ structures, including soft-tissues. In a relatively short period of time, normal and abnormal MRI disk morphology was established and displacement was relatively easily diagnosed. As such, MRI was regarded as the imaging technique of choice to depict TMJ disorders. In the 1990’s, Gadolinium enhancement improved identification of TMJ anatomic details due to diffusion of the contrast agent across the synovium, a so-called “arthrographic effect.” Contrast-enhanced MRI is also useful in the evaluation of inflammatory disorders such rheumatoid arthritis. Ultrasound examination of TMJ was also developed in this timeframe. Ultrasound is highly specific not only for demonstrating soft tissue alterations but also for the visualization of many bone abnormalities. Moreover, it is noninvasive, inexpensive and much less time consuming.

Most recently, there have been substantial improvements in MRI and ultrasound hardware and software that allow better visualization of smaller caliber TMJ landmarks such as the retrodiskal layers, lateral pterygoid muscle attachments, and joint fluid. These advances have allowed radiologists to detect early signs of TMJ disorders, thus avoiding the evolution to advanced, irreversible stages of TMJ dysfunction.

I would like to thank all the authors for their valuable contributions. Obviously, this issue could not have been possible without their diligence and attention to detail. Finally, I would like to thank Dr. Swartz for giving us this opportunity to publish our findings. I hope that readers find this issue useful.