mrimaster

MRI Shoulder Arthrogram : Protocol and Planning

Indications for MRI shoulder arthrogram

Contraindications

Patient preparation for MRI shoulder arthrogram

Arthrography

An arthrogram is an interventional procedure for the assessment of joint capsule pathologies. A radiologist will inject contrast medium into the joint space for the evaluation of joint abnormalities. Injections for mri shoulder arthrograms are normally done under x ray fluoroscopic guidance (some radiologists prefer to use ultrasound guidance)

Positioning for injection: Appropriate positioning of the shoulder is one of the most important parts of an arthrogram. Position the patient in supine with the arm externally rotated (palm of the hand up) to avoid the long head of the biceps tendon. Immobilize the arm using sandbags over the palm.

Marking for injection: Mark the skin over the upper medial quadrant of the humeral head, close to the articular joint line.

Injection: – Only a trained radiologist should perform the injection. Radiographers should only assist with the preparation. The following instructions are intended for a trained person who is authorized to perform joint injections.

Start by cleansing the designated site using betadine. Subsequently, administer local anesthesia to the skin and subcutaneous tissues using 1% lidocaine.

Typically, a 22 G 3½” needle is employed for all MR arthrogram injections.

Now position the needle tip directly onto the marked location and verify intra-articular needle placement under fluoroscopic guidance.

Proceed to inject 10 to 15cc of diluted Magnevist.

Positioning for MRI shoulder arthrogram

Recommended MRI Shoulder Arthrogram Protocols and Planning

MRI shoulder arthrogram localiser

A three-plane localizer must be taken at the beginning to localize and plan the sequences. Typically, localizers take less than 25 seconds and utilize T1 weighted low-resolution scans for this purpose. It is advisable to acquire additional localizers based on the initial localizer to obtain accurate coronal, axial, and sagittal views of the shoulder.

mri shoulder localizer planning image

T1 vibe 3d DIXON axial 0.8mm small FOV

Plan the axial 3D block on the coronal plane and angle the positioning block perpendicular to the glenohumeral joint. Check the positioning block in the other two planes. Use an appropriate angle in the sagittal plane, perpendicular to the humeral head. The slices should be sufficient to cover the entire shoulder joint from the top of the acromioclavicular joint to two slices below the inferior glenohumeral ligament (articular capsule). Adding saturation bands over the chest will help reduce ghosting artifacts caused by breathing. The phase direction should be anteroposterior to avoid wrap-around and ghosting artifacts from the chest.

MRI shoulder arthrogram planning of axial 3D scans

Parameters

TR

6-7

TE

2.39 4.77

SLICE

.8 MM

FLIP

12

PHASE

A>P

MATRIX

256X224

FOV

150-180

GAP

10%

NEX(AVRAGE)

2

T1 tse fat sat coronal 3mm SFOV

Plan the coronal slices on the axial plane and angle the positioning block parallel to the supraspinatus tendon. Do not exceed a 45° angle, as angling more than 45° will result in a change from the coronal plane to the sagittal plane. Verify the positioning block’s alignment in the other two planes. Use an appropriate angle in the sagittal plane, parallel to the humeral head. Ensure that the slices cover the entire shoulder joint, extending from the anterior portion of the coracoid process to two slices posterior to the humeral head. Additionally, consider adding an oblique saturation band over the chest to minimize ghosting artifacts caused by breathing.

planning and protocol of shoulder mri coronal scans

Parameters

TR

600-700

TE

15-20

FLIP

150

NEX

3

SLICE

3 MM

MATRIX

256X256

FOV

150

PHASE

A>P

OVERSAMPLE

100%

FAT SAT

SPAIR

T2 stir coronal 3mm SFOV

Plan the coronal slices on the axial plane and angle the positioning block parallel to the supraspinatus tendon. Do not exceed a 45° angle, as angling more than 45° will result in a change from the coronal plane to the sagittal plane. Verify the positioning block’s alignment in the other two planes. Use an appropriate angle in the sagittal plane, parallel to the humeral head. Ensure that the slices cover the entire shoulder joint, extending from the anterior portion of the coracoid process to two slices posterior to the humeral head. Additionally, consider adding an oblique saturation band over the chest to minimize ghosting artifacts caused by breathing.

Parameters

planning and protocol of shoulder mri coronal scans

TR

4000-5000

TE

110

FLIP

150

NEX

3

SLICE

3MM

MATRIX

256X256

FOV

150

PHASE

H>F

GAP

10%

TI

150

T1 tse fat sat sagittal 3mm SFOV

Plan the sagittal slices on the axial plane and angle the positioning block perpendicular to the supraspinatus tendon. Verify the positioning block in the other two planes. Ensure an appropriate angle is set in the coronal plane, parallel to the humerus. Include enough slices to cover the entire shoulder joint, from the deltoid muscle to the scapular notch. Additionally, consider adding an oblique saturation band over the chest to minimize ghosting artifacts caused by breathing.

Parameters

TR

600-700

TE

15-20

FLIP

150

NEX

3

SLICE

3 MM

MATRIX

256X256

FOV

150

PHASE

A>P

OVERSAMPLE

100%

FAT SAT

SPAIR