The diagnosis and management of acute facial nerve paralysis has been hampered difficulties in localizing the site and extent of the injury to the nerve. The evaluation of facial nerve palsy had been rapidly changed with new modalities of
radiologic
diagnosis: computed tomograghy(CT) and magnetic resonse imaging (MRI). CT. however, didn't allow direct visualization of the facial nerve and its pathologic conditions with a exception of facial nerve tumor.
Magnetic resonance imaging(MRI) enables the visualization of the facial nerve itself. As bone is washed out in the MRI technique and soft tissue becomes the imaged structure, the facial nerve as it traverses the temporal bone is directly
visualized.
With a paramagnetic enhancing agent, MRI reveals the pathologic conditions of the facial nerve, such as inflammation or edema. Especially, Gadolinium (Gd)-enhanced T1 weighted MR images have been shown to be useful for the evaluation of facial
nerve
pathology.
The authors studied a series of fourteen acute facial nerve paralysis patients with Gadolinium-enhanced MRI, Most cases(85%) demonstrated facial nerve enhancement, particularly in the labyrinthine and geniculate ganglion segments. The frequency
of
enhancement seemed to be lower in subjects with shorter interval from the onset of facial palsy to the MRI, as well as in subjects with lesser degrees of denervation by ENoG.
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