Parameters for Diffusion Weighted Magnetic Resonance Imaging for Temporomandibular Joint

Abstract

The purpose of this study was to determine optimum diffusion parameters for diffusion weighted imaging (DWI) techniques, including echo planer imaging (EPI), single-shot fast spin echo (SSFSE), and steady-state free precession (SSFP) in Magnetic Resonance Imaging (MRI) of the Temporomandibular Joint (TMJ). A polyethylene tube with distilled water was individually positioned at the external acoustic meatus foramen in each of three volunteers with normal healthy TMJs. Images were obtained using three types of DWI at differing diffusion parameters, b-factors, and diffusion moment. Signal intensity and imaging ability for various anatomical structures, including the distilled water, were evaluated from each image. The details of the anatomical structures of the TMJ were unidentifiable in the images produced with EPI and SSFSE, but were identifiable on the SSFP images. A diffusion moment value from 100mT/m*msec to 150 mT/m*msec for SSFP, in particular, restrained the signal intensity of the water, thereby protecting the comparably high image quality of the TMJ structure. In conclusion, only SSFP is capable of allowing interpretation of emerging pathologic conditions in the TMJ region, when used with a diffusion moment set at between from approximately 100mT/m*msec to 150 mT/m*msec.

A Potential Reference Point for Assessment of Condylar Bone Marrow of the Temporomandibular Joint On Proton Density Weighted Images

“…Quantitative evaluation of MR signal intensity, however, is still debated because of the difficulties of signal measurement. Otonari, et al 31 positioned a polyethylene tube containing distilled water at the external auditory foramen to determine the optimal sequence for diffusion- …”