Five patients with idiopathic sudden sensorineural hearing loss (ISSHL) were examined by a combination of high-resolution computed tomography and special magnetic resonance imaging techniques. By three-dimensional constructive interference in steady state magnetic resonance imaging excellent visualization of the membranous labyrinth was obtained. No fibrous or osseous obliteration of the intralabyrinthine fluid spaces was observed in all investigated temporal bones. The results provide further evidence for a viral pathogenesis of ISSHL.