MRI Clavicle
Indications for MRI Clavicle
- Infections of the bone, joint or soft tissue e.g. osteomyelitis, osteochondritis, myositis
- Intra-articular fractures or stress fractures involving the acromioclavicular (AC) joint
- Tumours and tumorous lesions of the clavicle
- Clavicular tuberculosis
- Multiple myeloma
- Ligament tear
- Metastatic disease
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 MRI Clavicle
- A satisfactory written consent form must be taken from the patient before entering the scanner room
- Ask the patient to remove all metal object including keys, coins, wallet, any cards with magnetic strips, jewellery, hearing aid and hairpins
- 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 down the weight of the patient
Positioning for MRI Clavicle
- Position patient in the supine position with head pointing towards the magnet (head first supine)
- Position the patient over the spine coil in the anatomical position. Place the body coil over the upper arm from shoulder to elbow, adjust the body coil so that it is positioned more towards the affected side.
- Securely tighten the body coil using straps to prevent respiratory artefacts
- The patient may be given a pillow and cushions under their legs for extra comfort
- Centre the laser beam localiser over the sternoclavicular joint
- Register the patient on the scanner as 'head first supine'
Recommended MRI clavicle Protocols, Parameters, and Planning
localiser 1
A three-plane localizer must be taken at the beginning to localize and plan the sequences. Localizers are usually less than 25 seconds in duration. T1-weighted low-resolution scans are used for this purpose.
clavicle MRI planning localiser
Plan the coronal and sagittal localizers on the axial localizer. For the coronal localizer, angle the positioning block parallel to the clavicle, and for the sagittal localizer, angle the positioning block perpendicular to the clavicle. For an additional axial localizer, position the third block over the clavicle on the sagittal plane.
T2 stir axial 3mm SFOV
Plan the axial slices on the coronal plane and angle the positioning block parallel to the clavicle. Check the positioning block in the other two planes. Use an appropriate angle in the sagittal plane, angling it perpendicular to the sternum. Ensure the slices cover the entire clavicle, extending at least 1 inch above the acromioclavicular joint and 1 inch below the humeral head. Apply saturation bands over the chest to minimize ghosting artifacts caused by breathing. For the phase direction, choose right to left or anteroposterior, with adequate oversampling to prevent wrap-around and ghosting artifacts from the chest. Whenever possible, utilize radial K space (BLADE) sequences to reduce motion artifacts.
Parameters
TR 4000-4500 | TE 110 | FLIP 130 | NEX 3 | SLICE 3 MM | MATRIX 256X256 | FOV 200-230 | PHASE A>P | GAP 10% | TI 150 |
T1 tse axial 3mm SFOV
Plan the axial slices on the coronal plane and angle the positioning block parallel to the clavicle. Check the positioning block in the other two planes. Use an appropriate angle in the sagittal plane, angling it perpendicular to the sternum. Ensure the slices cover the entire clavicle, extending at least 1 inch above the acromioclavicular joint and 1 inch below the humeral head. Apply saturation bands over the chest to minimize ghosting artifacts caused by breathing. For the phase direction, choose right to left or anteroposterior, with adequate oversampling to prevent wrap-around and ghosting artifacts from the chest. Whenever possible, utilize radial K space (BLADE) sequences to reduce motion artifacts.
Parameters
TR 400-600 | TE 15-25 | SLICE 3 MM | FLIP 130 | PHASE A>P | MATRIX 256X256 | FOV 200-230 | GAP 10% | NEX(AVRAGE) 2 |
T1 tse coronal 3mm SFOV
Plan the coronal slices on the axial plane and angle the positioning block parallel to the clavicle. Please note that angling the block beyond 45° will cause the coronal image to flip into the sagittal plane. Verify the positioning block in the other two planes. Apply an appropriate angle in the sagittal plane, keeping it parallel to the sternum. Ensure that the slices cover the clavicle, extending at least 1 cm anterior to the acromioclavicular joint and up to the aortic arch. To minimize breathing-related ghosting artifacts, include an oblique saturation band over the chest. The phase direction should be right to left, with adequate oversampling to prevent wrap-around and ghosting artifacts from the chest. Whenever possible, utilize radial K space (BLADE) sequences to reduce motion artifacts.
Parameters
TR 400-600 | TE 15-25 | SLICE 3 MM | FLIP 130 | PHASE R>L | MATRIX 256X256 | FOV 200-230 | GAP 10% | NEX(AVRAGE) 2 |
T2 stir coronal 3mm SFOV
Plan the coronal slices on the axial plane and angle the positioning block parallel to the clavicle. Please note that angling the block beyond 45° will cause the coronal image to flip into the sagittal plane. Verify the positioning block in the other two planes. Apply an appropriate angle in the sagittal plane, keeping it parallel to the sternum. Ensure that the slices cover the clavicle, extending at least 1 cm anterior to the acromioclavicular joint and up to the aortic arch. To minimize breathing-related ghosting artifacts, include an oblique saturation band over the chest. The phase direction should be right to left, with adequate oversampling to prevent wrap-around and ghosting artifacts from the chest. Whenever possible, utilize radial K space (BLADE) sequences to reduce motion artifacts.
Parameters
TR 3000-4000 | TE 110 | FLIP 130 | NEX 3 | SLICE 3 MM | MATRIX 256X256 | FOV 200-230 | PHASE R>L | GAP 10% | TI 130 |
T2 stir sagittal 3mm SFOV
Plan the sagittal slices on the axial plane, and angle the positioning block perpendicular to the clavicle. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane, perpendicular to the clavicle. The slices should cover the entire clavicle, extending at least 1 cm past the acromioclavicular joint laterally and 1 cm past the sternoclavicular joint medially. To minimize breathing-related ghosting artifacts, consider adding an oblique saturation band over the chest. For phase direction, use either anteroposterior or head-to-feet, incorporating sufficient oversampling to avoid wrap-around and ghosting artifacts. Whenever possible, utilize radial K space (BLADE) sequences to reduce motion artifacts.
Parameters
TR 4000-5000 | TE 110 | FLIP 130 | NEX 3 | SLICE 3 MM | MATRIX 256X192 | FOV 170-200 | PHASE A>P | GAP 10% | TI 130 |