Study Of High-Resolution Magnetic Resonance Imaging Of Inner Ear And Its Clinic Application

Objective: To probe into the application value of high-resolution magnetic resonance imaging technology (HRMRI) in diagnose of abnormal membrane labyrinth of inner ear and cochleovestibular nerve,to offer the objective imaging basis for clinic non-invasive evaluation of inner ear.Methods:1. We performed two-dimensional spin echo TI weighted image(2D SE TiWI)axial scanning to 51 normal adults, 12 clinically suspected congenital sensorineural hearing loss (SNHL) children and 71 clinically suspected patients of inner ear; we performed high-resolution three-dimensional turbo spin echo T2 weighted image (3D TSE T2WI) scanning of temporal bone and then performed bilateral oblique plane sagittal scanning with 3D TSE T2WI or balanced - tubor field echo(B-TFE). Of 134 patients, enhanced TiWI scanning was performed in 32 patients.2. We performed mutiplanar reformation (MPR) and maximum intensityprojection (MIP) with collected 3D data and observed the normal structure and lesion of membrane labyrinth from all directions.3. We observed cochleovestibular nerve and facial nerve size hi three parts of normal adults' IAC (entrance to IAC; medial portion of IAC; lateral portion of IAC), the distance from cochleovestibular nerve branch to the lateral portion of IAC and lesion of inner ear.4. All cases were evaluated by two senior doctors in double-blind method; as to the results of HRMRI examination, we applied SPLM statistic software to statistic treatment to calculate the average and standard deviation.Result:1. Subtle anatomical structure of cochleovestibular nerve, facial nerve and inner ear membrane labyrinth could be clearly shown in 268 ears of 134 cases.2. Of 51 cases, the diameter of facial nerve, superior vestibular nerve, inferior vestibular nerve and cochlear nerve of 102 adults' ears in IAC was 1.20±0.12mm, 1.09±0.10mm,1.00±0.13mm and 1.25±0.10mm respectively in the lateral portion of IAC. 1.20±0.12mm , 1.09±0.10mm, 1.00±0.13m and 1.31±0.16mm respectively in the medial portion of IAC. The diameter of facial nerve and cochleovestibular nerve was 1.20±0.12mm and 1.61 ±0.22 mm respectively in the entrance to IAC. The distance from cochleovestibular nerve branch to the lateral portion of IAC was 6.03 ± 1.71mm,while the distance from vestibular nerve branch to the lateral portion of LAC was 1.83 ± 0.52mm. Comparing the relative size of the four nerves in the lateral portion of IAC, we found that of 102 ears in 51 cases, cochlear nerve of 94 ears (92.2%) was larger than either the superior or inferior vestibular nerve, and cochlear nerve of 64 ears (64.7%) was similar to or larger than facial nerve.3. Of 12 clinically suspected congenital SNHL children, four suffered labyrinthmalformation in 7 ears, of whom one suffered type Michel in one ear and three type Mondini in 6 ears and four suffered large vestibular aqueduct in 8 ears. 8 patients suffered deficiency of cochleovestibular nerve to different degree in 15 ears.4. Of 71 clinically suspected patients of inner ear, one suffered semicircular canals lesion in one ear, 6 acquired SNHL with atrophy of cochlear nerve in 8 ears, 16 acoustic schwannoma in 16 ears and atrophy close to cochlear nerve in 10 ears.Conclusion:1. The size of the facial nerve and cochleovestibular nerve in IAC has individual difference.2. By HRMRI can the elaborate anatomical structure of inner ear nerve be shown and can slight lesion be found. And oblique plane sagittal HRMRI plays peculiar imaging role in finding cochlear nerve and vestibular nerve lesion.3. By inner ear HRMRI, the subtle anatomical structure of membrane labyrinth and the lesion of inner ear can be shown. This offers bases for objective, non-invasive imaging diagnose, which can not be replaced by other imaging approaches.