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). the internal auditory canal (IAC), or the inner ear. Check the positioning block in the other two planes. The cochlear nerve (also auditory or acoustic neuron) is one of two parts of the vestibulocochlear. 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. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be. 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) In addition, the features at pre- and postprocedural MRI will be discussed to help. In the posterior quadrants are the two vestibular nerves, while in the anterior quadrants are the other two - the mnemonic can be used to remember their position.Contraindications internal auditory meatus(iams) MRI scanĪny electrically, magnetically or mechanically activated implant (e.g. The purpose of this review is to provide an overview of the most useful MRI sequences for internal auditory canal and labyrinthine imaging, review the relevant anatomy, and discuss the expected appearances of the most commonly encountered pathologic enti-ties. In each quadrant, there is the passage of one nerve (see picture). Three components of the vestibulocochlear nerve (CN VIII)įour are the nerves and four are the quadrants of the IAC: anterosuperior, anteroinferior, posterosuperior, posteroinferior. A mnemonic to remember the relative position of nerves inside the internal auditory canal (IAC) is: Regardless of suspicion for peripheral or central etiology, for episodic or persistent vertigo, if imaging is indicated the best test is MRI Brain and internal.

Internal auditory canal mri