Fast spin-echo high-resolution MR imaging of the inner ear.

Abstract

Advances in MR imaging continue to improve our ability to evaluate temporal bone anatomy and disease. CT remains the procedure of choice for fine-detail imaging of bone structures such as ossicular anatomy, but it is not the ideal imaging technique for soft-tissue structures (e.g., the membranous labyrinth and neural structures). Conventional spin-echo MR techniques used to image these structures cannot yield excellent contrast and spatial resolution in clinically acceptable time frames. Conventional spin-echo T1-weighted images lack tissue contrast between fluid (e.g., CSF, endolymph, perilymph), neural tissue, otic capsule septa, and surrounding temporal bone. Conventional T2-weighted imaging of the inner ear is needed to reveal the natural contrast between fluid, neural structures, and bone; unfortunately, the use of conventional T2-weighted images is limited by time constraints when large-matrix, thin-section techniques with more than one excitation are used. Fast spin-echo imaging is a recently developed technique that can provide T2-weighted, thin-section (2-mm) high-resolution images with excellent contrast in a fraction of the time needed for conventional spin-echo techniques. This speed advantage allows us to obtain high-resolution images in clinically acceptable time frames. Images produced by this technique are a useful addition, in conjunction with routine T1- and T2-weighted spin-echo images, in the diagnosis of disorders of the inner ear.