Assessment of Meniere's disease from a radiological aspect - saccular otoconia as a cause of Meniere's disease?

CONCLUSION: Significant reduced visualization of the reuniting duct (ductus reuniens; RD), saccular duct (SD) and endolymphatic sinus (ES) in Meniere's disease (MD) compared with normal control ears on three-dimensional (3D) CT imaging suggests the blockage of endolymphatic flow there with radiodense substances, which may be explained by dislodged otoconia from the saccule. These structures could be involved in the pathogenesis of MD. OBJECTIVE: This study was designed to visualize and assess the RD, SD and ES in patients with MD using 3D CT. METHODS: Sixty-two patients with a definite diagnose of unilateral MD, based on criteria proposed by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), were compared with contralateral ears and normal controls (26 ears) using 3D CT. The RD, SD and ES were scrutinized for patency on 3D CT images. RESULTS: MD ears showed loss of continuity of the RD, SD and ES based on evaluation of 3D CT images, and differed significantly from normal healthy control ears (p < 0.01).

Non-invasive assessment of otolith formation during development of the Japanese red-bellied newt, Cynops pyrrhogaster.

Pre-mated adult female newts and embryos have been flown on the International Microgravity Laboratory-2 (IML-2) Space Shuttle flight in 1994 (Wiederhold et al., 1992b). With the specimens available from this flight, the calcification of otoliths, ulna, radius and backbone of the flown larvae and adult newts were analyzed. The experiments presented here studied the development of the otoliths on the ground. Otoliths of living newts, from embryo to adult, were observed in situ with the application of a new X-ray and bio-imaging analyzer system. For the establishment of this method, newts at different developmental stages were used. An imaging plate temporarily stores the X-ray energy pattern at the bio-imaging analyzer. A latent image on the imaging plate was transformed into a digital time series signal with an image reader. Acquired digital information was computed with the image processor. The processed information was recorded on film with an image recorder, in order to visualize it on an enlargement computed radiograph. To analyze development of the otoliths, photo-stimulated luminescence level was detected by an image analyzer, using transmitted X-ray photons. A single clump of otoconia could first be seen at stage 33. Stage-36 embryos first have distinguishable otoliths, with the utricle in front and saccule behind. Our results show that this X-ray method detects the otoliths equally as well as sectioning. In the newt, the mandibular/maxillary bone formed before the spine. It is suspected that for the newt embryo, living in water, feeding becomes necessary prior to support of the body.