Larynx MRI
Indications for Larynx mri scan
- Treatment planning for radiation therapy
- Evaluation of response to treatment
- Pre-operative evaluation of tumours
- Staging of larynx malignancy
- Vocal cord paralysis
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 Larynx 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
- Ask the patient to undress and change into a hospital gown
- 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
- If possible provide a chaperone for claustrophobic patients (e.g. relative or staff )
- 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 Larynx mri scan
- Head first supine
- Position the head in the head and neck coil and immobilise with cushions
- Give cushions under the legs for extra comfort
- Centre the laser beam localiser over the mid neck (1 inch below the chin in chin down position)
Recommended Larynx MRI Protocols, Parameters and Planning
Larynx mri localiser
A three-plane localizer must be taken at the beginning to localize and plan the sequences. Localizers are normally less than 25 seconds and are T2-weighted low-resolution scans.
T2 DIXON (T2 in-phase and T2 fat sat) coronal 2mm 160MM FOV
Plan the coronal slices on the sagittal plane and align the planning block parallel to the cervical spine. Verify the planning block in the other two planes. Ensure an appropriate angle in the axial plane, parallel to the transverse process of the cervical spine. The slices should adequately cover the larynx from the chin to the spinal cord. The field of view (FOV) must encompass the larynx from the upper lips to the T1 vertebra. Maintain a head-to-feet phase direction in the coronal scans with 100% oversampling to prevent wrap-around artifacts.
During sequence acquisition, it is crucial to instruct the patient not to swallow. In our imaging department, we allow 30 seconds after each scan for the patient to swallow saliva. This precaution helps minimize motion artifacts in the neck during image acquisition. Additionally, the use of saturation bands above and below the coronal block can effectively reduce arterial pulsation and swallowing artifacts.
Parameters
TR 5000-6000 | TE 90 | FLIP 151 | NEX 2 | SLICE 2 MM | MATRIX 224X224 | FOV 160-165 | PHASE H>F | GAP 10% | OS 100% |
T1 tse coronal coronal 2mm 160MM FOV
Plan the coronal slices on the sagittal plane and align the planning block parallel to the cervical spine. Verify the planning block in the other two planes. Ensure an appropriate angle in the axial plane, parallel to the transverse process of the cervical spine. The slices should adequately cover the larynx from the chin to the spinal cord. The field of view (FOV) must encompass the larynx from the upper lips to the T1 vertebra. Maintain a head-to-feet phase direction in the coronal scans with 100% oversampling to prevent wrap-around artifacts.
During sequence acquisition, it is crucial to instruct the patient not to swallow. In our imaging department, we allow 30 seconds after each scan for the patient to swallow saliva. This precaution helps minimize motion artifacts in the neck during image acquisition. Additionally, the use of saturation bands above and below the coronal block can effectively reduce arterial pulsation and swallowing artifacts.
Parameters
TR 500-700 | TE 15-25 | SLICE 2 MM | FLIP 140 | PHASE H>F | MATRIX 256X224 | FOV 160-165 | GAP 10% | NEX(AVRAGE) 2 |
T1 tse axial 2mm 160MM FOV
Plan the axial slices on the sagittal plane: angle the planning block perpendicular to the cervical spine. Check the positioning block in the other two planes. Ensure an appropriate angle in the coronal plane (perpendicular to the cervical spine). Slice coverage should extend from the upper lips down to the T1 vertebra. The phase direction in the axial scans must be from right to left with 100% oversampling. This reduces wrap-around, arterial pulsation, and swallowing artifacts.
It’s important to instruct the patient to avoid swallowing during sequence acquisition. The use of saturation bands on the top and bottom of the axial block can further reduce artifacts related to arterial pulsation and swallowing.
Parameters
TR 500-700 | TE 15-25 | SLICE 2 MM | FLIP 140 | PHASE R>L | MATRIX 256X224 | FOV 160-165 | GAP 10% | NEX(AVRAGE) 2 |
T2 DIXON (T2 in-phase and T2 fat sat) axial 2mm 160MM FOV
Plan the axial slices on the sagittal plane: angle the planning block perpendicular to the cervical spine. Check the positioning block in the other two planes. Ensure an appropriate angle in the coronal plane (perpendicular to the cervical spine). Slice coverage should extend from the upper lips down to the T1 vertebra. The phase direction in the axial scans must be from right to left with 100% oversampling. This reduces wrap-around, arterial pulsation, and swallowing artifacts.
It’s important to instruct the patient to avoid swallowing during sequence acquisition. The use of saturation bands on the top and bottom of the axial block can further reduce artifacts related to arterial pulsation and swallowing.
Parameters
TR 5000-6000 | TE 90 | FLIP 151 | NEX 2 | SLICE 2 MM | MATRIX 224X224 | FOV 160-165 | PHASE R>L | GAP 10% | OS 100% |
DWI epi2scan trace axial 3mm
Plan the axial slices on the sagittal plane: angle the planning block perpendicular to the cervical spine. Check the positioning block in the other two planes. Ensure an appropriate angle in the coronal plane (perpendicular to the cervical spine). Slice coverage should extend from the upper lips down to the T1 vertebra. The phase direction in the axial scans must be from right to left with 100% oversampling. This reduces wrap-around, arterial pulsation, and swallowing artifacts.
The use of saturation bands on the top and bottom of the axial block can further reduce artifacts related to arterial pulsation and swallowing.
Parameters
TR 5000-6000 | TE 110 | FLIP 130 | NEX 3 7 | SLICE 5 MM | MATRIX 192X192 | FOV 180-1900 | PHASE R>L | GAP 10% | B VALUE 0 800 |
T2 tse sagittal 2mm 160MM FOV
Plan the sagittal slices on the coronal plane: align the positioning block parallel to the cervical spine. Verify the positioning block in the other two planes. Ensure an appropriate angle in the axial plane (parallel to the spinous processes of the cervical spine). The slices should adequately cover the larynx from the right parotid gland to the left parotid gland. The field of view (FOV) should be wide enough to encompass the larynx from the upper lip to the T1 vertebra.Set the phase direction from head to feet with a 100% oversample.
It’s crucial to instruct the patient to refrain from swallowing during sequence acquisition. Utilizing saturation bands above and below the sagittal block can help reduce arterial pulsation artifacts.
Parameters
TR 4000-5000 | TE 110 | FLIP 130 | NEX 2 | SLICE 2 MM | MATRIX 256X256 | FOV 160-165 | PHASE H>F | GAP 10% | OVERSAMPLE 100% |
T1 VIBE DIXON\SPACE FAT SAT axial .9mm ISOTROPIC 160MM FOV
Plan the axial 3D block on the sagittal plane: angle the planning block perpendicular to the cervical spine. Check the positioning block in the other two planes. Ensure an appropriate angle in the coronal plane (perpendicular to the cervical spine). Slice coverage should extend from the upper lips down to the T1 vertebra. The phase direction in the axial scans must be from right to left with 100% oversampling. This reduces wrap-around, arterial pulsation, and swallowing artifacts.
The use of saturation bands on the top and bottom of the axial block can further reduce artifacts related to arterial pulsation and swallowing.
Parameters
TR 6-7 | TE 2.39 4.77 | SLICE .9 MM | FLIP 12 | PHASE R>L | MATRIX 224X208 | FOV 160-170 | GAP 10% | NEX(AVRAGE) 2 |