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Facial Nerve (3D Protocol) MRI

Indications for Facial nerve MRI scan

  • Assessment of inflammatory disorders affecting the facial nerve.
  • Identifying soft tissue abnormalities around the facial nerve.
  • Evaluation of neoplasms involving the facial nerve
  • Diagnosis and assessment of hemifacial spasm.

Contraindications

  • Any electrically, magnetically or mechanically activated implant (e.g. cardiac pacemaker, insulin pump biostimulator, neurostimulator, cochlear implant, and hearing aids)
  • Intracranial aneurysm clips (unless made of titanium)
  • Pregnancy (risk vs benefit ratio to be assessed)
  • Ferromagnetic surgical clips or staples
  • Metallic foreign body in the eye
  • Metal shrapnel or bullet

Patient preparation for Facial nerve MRI scan

  • A satisfactory written consent form must be taken from the patient before entering the scanner room
  • Ask the patient to remove all metal objects including keys, coins, wallet, cards with magnetic strips, jewellery, hearing aid and hairpins
  • If possible provide a chaperone for claustrophobic patients (e.g. relative or staff )
  • Contrast injection risk and benefits must be explained to the patient before the scan
  • Gadolinium should only be given to the patient if GFR is > 30
  • Offer earplugs or headphones, possibly with music for extra comfort
  • Explain the procedure to the patient
  • Instruct the patient to keep still
  • Note the weight of the patient

Positioning for Facial nerve MRI scan

  • Head first supine
  • Position the head in the head coil and immobilise with cushions
  • Give cushions under the legs for extra comfort
  • Centre the laser beam localizer over the glabella
mri brain planning and positioning

Recommended Facial Nerve MRI Protocols and Planning

Facial nerve MRI localiser

To plan the sequences, it is necessary to acquire a three-plane localizer, which typically consists of T1 weighted low-resolution scans lasting less than 25 seconds.

T2 3D SPACE or CISS axial .6mm

Plan the axial slices on the sagittal plane; angle the positioning block parallel to the hard palate. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane (perpendicular to the nasal septum). Slices must be sufficient to cover the face from the glabella down to the lower lips. If your scanner allows, consider using a small FOV 3D sequence to achieve the best results. We recommend performing these scans on a 3T scanner or a 1.5T scanner with a high-channel head coil for optimal image quality.

MRI facial nerve protocol and planning of axial scans

Parameters

TR

2000-2500

TE

250-300

SLICE

.6MM

FLIP

150

PHASE

R>L

MATRIX

256X256

FOV

160-180

GAP

10%

NEX(AVRAGE)

1.6

These isotropic 3D scans can be reconstructed into coronal and sagittal planes, enabling the visualization of the anatomy in three dimensions.

T1 3D SPACE axial .9mm

Plan the axial slices on the sagittal plane; angle the positioning block parallel to the hard palate. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane (perpendicular to the nasal septum). Slices must be sufficient to cover the face from the glabella down to the lower lips. If your scanner allows, consider using a small FOV 3D sequence to achieve the best results. We recommend performing these scans on a 3T scanner or a 1.5T scanner with a high-channel head coil for optimal image quality.

MRI facial nerve protocol and planning of axial scans

Parameters

TR

500-600

TE

18-20

SLICE

.9MM

FLIP

T1 vre

PHASE

R>L

MATRIX

256X256

FOV

170-190

GAP

10%

NEX(AVRAGE)

2

T2 STIR 3D SPACE axial .9 mm

Plan the axial slices on the sagittal plane; angle the positioning block parallel to the hard palate. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane (perpendicular to the nasal septum). Slices must be sufficient to cover the face from the glabella down to the lower lips. If your scanner allows, consider using a small FOV 3D sequence to achieve the best results. We recommend performing these scans on a 3T scanner or a 1.5T scanner with a high-channel head coil for optimal image quality.

MRI facial nerve protocol and planning of axial scans

Parameters

TR

3000-4000

TE

250-300

SLICE

.9MM

TI

160

PHASE

R>L

MATRIX

224X224

FOV

170-200

GAP

10%

NEX(AVRAGE)

2

For contrast enhanced scans

After administering the IV gadolinium DTPA injection, please continue with the following sequences. The document below grants access to the manufacturer's recommended dosage of gadolinium DTPA injection.
Access the manufacturers' recommended guidelines regarding dosage and contraindications for gadolinium DTPA injection by clicking here.

T1 VIBE DIXON axial .6mm SFOV ISO post contrast

Plan the axial 3D block on the sagittal plane; angle the positioning block parallel to the hard palate. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane (perpendicular to the nasal septum). Slices must be sufficient to cover the face from the glabella down to the lower lips. If your scanner allows, consider using a small FOV 3D sequence to achieve the best results. We recommend performing these scans on a 3T scanner or a 1.5T scanner with a high-channel head coil for optimal image quality.

MRI facial nerve protocol and planning of axial scans

Parameters

TR

7-8

TE

2.39 4.77

SLICE

.6 MM

FLIP

12-15

PHASE

R>L

MATRIX

192X192

FOV

170mm

GAP

10%

NEX(AVRAGE)

2

The post-contrast isotropic 3D scans can be reconstructed into coronal and sagittal planes, enabling the visualization of the anatomy in three dimensions.