Congenital internal auditory canal stenosis can be an important cause of sensorineural hearing loss, facial nerve palsy, and vestibular dysfunction. Two cases revealed bilateral internal auditory canal stenosis, and others were unilaterally involved cases. In all cases, the diameter of the internal auditory canal was less than 2 mm on high-resolution temporal bone computed tomography (CT) scan. Hearing loss including deafness was found in five cases, vestibular function loss in four cases, and profound functional loss of facial nerve in two cases. Chief presenting symptoms were hearing loss, facial nerve palsy, dizziness, and tinnitus. A retrospective analysis including clinical manifestation and radiological findings was made for seven patients who were diagnosed with congenital internal auditory canal stenosis from 1996 to 2002. 0.2 mL/kg in adults, children and infants.Congenital internal auditory canal stenosis is a rare cause of sensorineural hearing loss in children. The recommended dose of gadolinium DTPA injection is 0.1 mmol/kg, i.e. Use T1 SE axial and coronal after the administration of IV gadolinium DTPA injection(copy the planning outlined above). T1 pre contrast and post contrast scans are only required in case of tumor present in internal auditory canal. Slices must be sufficient to cover IAMS from the hippocampus up to the line of the C1 vertebral body.

An appropriate angle must be given in the sagittal plane (perpendicular to the brain stem). Plan the axial slices on the coronal plane angle the position block parallel to the line along right and left IAMS(as shown in the diagram).Check the positioning block in the other two planes. Slices must be sufficient to cover IAMS from the posterior border of sphenoid sinus up to the line of the fourth ventricle. An appropriate angle must be given in the sagittal plane (parallel to the brain stem). Plan the coronal slices on the axial plane angle the position block parallel to the line along right and left IAMS(as shown in the diagram).Check the positioning block in the other two planes. An appropriate angle must be given in coronal plane on a tilted head (perpendicular to the line of 3rd ventricle and brain stem). Check the positioning block in the other two planes. Slices must be sufficient to cover the whole brain from the vertex up to the line of the foramen magnum. Plan the axial slices on the sagittal plane angle the position block parallel to the anterior and posterior margin of the corpus callosum. Suggested protocols, parameters and planningĪ three plane localiser must be taken in the beginning to localise and plan the sequences. Give cushions under the legs for extra comfortĬentre the laser beam localizer over the glabella Position the head in the head coil and immobilise with cushions Offer earplugs or headphones, possibly with music for extra comfort Gadolinium should only be given to the patient if GFR is > 30 relative or staff )Ĭontrast injection risk and benefits must be explained to the patient before the scan If possible provide a chaperone for claustrophobic patients (e.g. Patient preparatio n i nternal auditory meatus(iams) MRI scanĪ satisfactory written consent form must be taken from the patient before entering the scanner roomĪsk the patient to remove all metal objects including keys, coins, wallet, cards with magnetic strips, jewellery, hearing aid and hairpins Pregnancy (risk vs benefit ratio to be assessed) Intracranial aneurysm clips (unless made of titanium) cardiac pacemaker, insulin pump biostimulator, neurostimulator, cochlear implant, and hearing aids) Contraindications internal auditory meatus(iams) MRI scanĪny electrically, magnetically or mechanically activated implant (e.g.

Auditory canal