| Objective: Inner ear disease is the common reason to result in deafness. However, because of the inner ear being located in deep parspetrosa ossis temporalis and its structure being tiny and complicated, the clinician of otology could not intuitively find where the inner ear pathological changes were, which enormously affected the diagnosis and treatment to diseases. With the development of many kinds of imaging technique of MRI and special software, MRI can intuitively and three-dimensionally display the refined structures of the membranous labyrinth. The principle of this technique is that using the heavily T2-Weighted technique, the tissues with fluid display sky-high signal, but the signals of the tissues without fluid obviously decrease with the echo time prolonging. The labyrinthus membranaceus of the inner ear is full of endolympha fluid. There is perilympha between the labyrinthus membranaceus and bony labyrinth. In addition, the inner acoustic meatus is full of cerebrospinal fluid. So using the heavily T2-Weighted technique, we could clearly display the structure of the labyrinthus membranaceus and inner acoustic meatus which were full of fluid, thereby achieving the effect of inner ear visualization. We took the MRI examinations on patients who suffered from SHL with vertigo, subjective tinnitus, tiny acoustic neuroma and large aqueduct of vestibule syndrome. Through MRI examination, we observed the morphology changes of every part of membranous labyrinth and measured the major structures of inner ears. Then, we wanted to explore the diagnostic criteria and raise the diagnostic rate of the inner ear diseases and would offer information for clinical treatment in the future. Methods: The MRI examinations were performed on 30 patients suffered from sudden hearing loss with vertigo (15 men and 15 women), 30 patients suffered from subjective tinnitus (15 men and 15 women), 30 adult volunteers who were healthy and had no ear diseases (15 men and 15 women), 3 patients suffered from acoustic neuroma (3 women), 1 patient suffered from large aqueduct of vestibule syndrome (1 men). The patients came from our out-patient clinic or hospital room from 2003 to 2005, and fulfilled the criteria of sudden hearing loss with vertigo,subjective tinnitus,acoustic neuroma and large aqueduct of vestibule syndrome. Except registering general state of health and undergoing common examination,otology examination and audiology examination, all the subjects lay on the examination bed with their ears symmetrical under the quiet environment. Then all the original images were transferred to an online workstation and underwent image postprocessing. We observed and measured the structures of the inner ear utilizing the ALATOVIEW software which wasinstalled on the workstation. Results 1 Morphology describe of MRI 1.1 All the structures of inner ears and inner acoustic meatus of the control subjects could be visualized clearly. 1.2 The MRI positive rate of the patients who suffered from SHL with vertigo was 53.3%. The image of nine patients who lightly suffered from SHL with vertigo displayed that the initial segment of some single semicircular canals expanded, the other single semicircular canals expanded topically. The thickness of semicircular canals were inequable. The edge of semicircular canals were coarse , not smooth and glossy. The sacculus and utriculus vestibule expanded in different degree. The cochlear canal displayed that the thickness were asymmetrical, especially the basal turn displayed more obviously. The image of seven patients who severely suffered from SHL with vertigo displayed that two or three semicircular canals expanded like nodosity or cystic form, even displayed like rosary. The image of the sacculus and utriculus vestibuli obviously enlarged. The edges of basal turn of cochlear canal were not smooth and glossy, displayed that the thicknesses of basal turn of cochlear canal were unevenness like a bunch of pearls. Among them, the MRI of the most severe patient displayed that the image of posterior semicircular canal on the trouble side discontinue from different axial views and angles. There were almost no structure changes of the inner ear on MRI for all patients afterfollow-up 5-7 months. 1.3 The MRI positive rate of the patients who suffered from tinnitus is only 20.0%. There were only six patients whose MRI had slight imaging changes among thirty patients who suffered from the tinnitus. 1.4 The MRI positive rate of the patients who suffered from SHL with vertigo is 53.3%. The MRI positive rate of the patients who suffered from tinnitus is only 20.0%. The Chi-square test result is that:χ2=5.813, p=0.016. There was a significant difference between the MRI positive rate of SHL with vertigo group and tinnitus group. 1.5 The MRI of the patients who suffered from acoustic neuroma displayed that the inner acoustic meatus on the trouble side expanded, there was a filling defect look like glaebule shape in the inner acoustic meatus ncurolymph and the acoustic nerve could be seen clearly. 1.6 The MRI of the patients who suffered from large aqueduct of vestibule syndrome displayed that there was a extradural high-signal intumescence which was displayed like sliver shape and the edge of its was smooth and neat between the sigmoid sinus of the posterior cranial fossa and inner acoustic meatus. 2 The index data of MRI 2.1 SHL with vertigo group: male lymph volume (0.259±0.018)mm3, female lymph volume (0.253±0.015)mm3, male vestibule vertical diameter(3.329±0.263)mm, female vestibulevertical diameter(3.122 ±0.186)mm, anterior semicircular canal caliber (1.025±0.213)mm, posterior semicircular canal caliber(1.277 ±0.182)mm, horizontal semicircular canal caliber(1.225 ±0.183)mm, basis cochleae caliber(1.394 ±0.127)mm, There was a significant difference between the male-female lymph volume of SHL with vertigo group and that of normal control group (p<0.05). There was no significant difference of the rest indexes between the SHL with vertigo group and normal control group (p>0.05). 2.2 The recheck group of SHL with vertigo: male lymph volume(0.258±0.019)mm3, female lymph volume(0.252±0.015)mm3, male vestibule vertical diameter(3.330±0.262)mm, female vestibule vertical diameter(3.120±0.185)mm, anterior semicircular canal caliber(1.025 ±0.213)mm, posterior semicircular canal caliber(1.276 ±0.182)mm, horizontal semicircular canal caliber(1.225±0.183)mm, basis cochleae caliber(1.394±0.126)mm, There was no significant difference of the above-mentioned indexes between the recheck group of SHL with vertigo and the SHL with vertigo group (p>0.05). 2.3 Tinnitus group: male lymph volume(0.253±0.019)mm3, female lymph volume(0.230 ±0.013)mm3, male vestibule vertical diameter(3.234±0.274)mm, female vestibule vertical diameter(3.135 ±0.168)mm, anterior semicircular canal caliber(1.044 ±0.119)mm, posterior semicircular canal caliber(1.197 ±0.157)mm, horizontal semicircular canal caliber(1.208 ±0.136)mm, basis cochleae caliber(1.386 ±0.102)mm. There was no significant difference of the above-mentioned indexes between the tinnitus group and normal control group (p>0.05). 2.4 Acoustic neuroma group: The maximum section of tumor in acoustic meatus of the three acoustic neuroma patients were (9.100×4.240)mm, (9.700×5.100)mm, (12.200×14.100)mm. 2.5 Large aqueduct of vestibule syndrome: The maximum width of the midposition of endolymphatic sac in the temporal bone of the large aqueduct of vestibule syndrome patient was 2.470 mm. This was bigger than the diagnosis standard of the large aqueduct of vestibule syndrome(1.5mm). 3 There was a positive correlation between the lymph volume of the male patients who suffered from SHL with vertigo(0.259±0.018) mm3and the pure tone average(63.60±25.16)dB, (r=0.526, p=0.0022);There was a positive correlation between the lymph volume of the female patients who suffered from SHL with vertigo(0.253 ±0.015)mm3 and the pure tone average(66.67±26.05)dB, (r=0.714, p<0.0001). Conclusion: The results demonstrated: 1. MRI can intuitively and three-dimensionally display the refined structures of the membranous labyrinth. It can not be replaced by other methods. 2. Membranous labyrinth of the inner ears showed irreversible morphology structure changes on MRI in the patients who suffered from SHL with vertigo. There was a significant difference between the lymph volume of SHL with vertigo group and that of normal control group. There was a...
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