SUBMILLIMETER-RESOLUTION MR OF THE ENDOLYMPHATIC SAC IN HEALTHY-SUBJECTS AND PATIENTS WITH MENIERE DISEASE

PURPOSE: To evaluate the utility of submillimeter-resolution MR imagin g for direct depiction of functional soft-tissue components of the int raosseous endolymphatic duct and sac in healthy subjects and in patien ts with Meniere disease. METHODS: Axial MR images were acquired of 14 patients with Meniere disease and 14 healthy volunteers at 1.5 T with a short-echo-time steady-state 3-D gradient-echo sequence. Seven volun teers and eight patients were also studied with a T1-weighted 3-D spoi led gradient-echo sequence. T1/T2 relaxation times were estimated from studies with multiple flip angles. RESULTS: Independent of the acquis ition method, intraosseous endolymphatic ducts and sacs were seen unam biguously in the ears of 20 of 21 healthy subjects but in only four of 12 asymptomatic and two of 10 symptomatic ears of patients with Menie re disease. Other labyrinthine structures were well depicted in all su bjects, Furthermore, shorter relaxation times were measured for the co ntents of the vestibular aqueduct than for other labyrinthine structur es. CONCLUSION: In our high-resolution study, the intraosseous portion s of the endolymphatic ducts and sacs were depicted in most of the hea lthy subjects. They were frequently not seen in either ear of patients with unilateral Meniere disease, presumably because of their small si ze.