Such as Michel malformation, Mondini malformation, cochlear duct dilatation and otosclerosis. Some scholars have compared the diagnostic value of CT and MR in large vestibular catheter. Results MR can directly display the fluid in endolymphatic vessels and endolymphatic sac, and can better reflect their morphological changes. Some scholars believe that MR is valuable in the diagnosis of minimal lesions of membranous labyrinth.
In particular, enhanced magnetic resonance imaging of labyrinth is easy to find small tumors in labyrinth. In addition, it is of great significance for the diagnosis of labyrinthitis, hydrolabyrinthitis and Meniere's disease, but when labyrinthitis has not caused morphological changes, MR can not show the subtle changes of the inner ear like gross anatomy.
Imaging principle:
In recent years, due to the application of MR special software, especially the development of MR water imaging technology, the fine structure of membrane labyrinth can be displayed intuitively and stereoscopically. The imaging of membranous labyrinth and internal auditory canal is based on the principle of water imaging, that is, the weighted T2 effect of long TR and ultra-long TE is used to improve the signal intensity of cerebrospinal fluid and lymph in membranous labyrinth of internal auditory canal.
It becomes a very high signal, which is in sharp contrast with the surrounding low signal bone structure, highlighting the images of the internal auditory canal and the membranous labyrinth, thus achieving the effect of "contrast" between the internal auditory canal and the membranous labyrinth. However, MR hydrography can not satisfactorily display labyrinthine duct, nor can it distinguish between endolymphatic and exolymphatic, nor can it distinguish between elliptical bursa and balloon merged into high signal bursa.
Magnetic resonance labyrinthine imaging can provide reliable imaging anatomical basis for inner ear microsurgery, especially plays an important role in the selection of indications for cochlear surgery, including excluding surgical contraindications and possible normal variations, but it is not suitable for post-cochlear transplant reexamination. Some scholars have reported that MR can satisfactorily display the congenital abnormalities of the inner ear and understand the degree and location of the undeveloped and dysplasia of the inner ear.