mriprotocol - SHOULDER MRI PROTOCOL

AXIAL REFERENCE LINES

Axial Imaging Plane

Prescribe plane parallel to humeral shaft. Cover from AC joint through proximal humeral diaphysis.

Use coronal LOC and plane is straight horizontal (IF THE SHOULDER IS MARKEDLY ANGLED, YOU CAN ANGLE THE AXIAL IMAGES PERPENDICULAR TO THE GLENOHUMERAL JOINT)

- Cover from top of AC joint down and try to cover to the inferior portion of

the glenohumeral joint axillary pouch

- No Sat Band

CORONAL REFERENCE LINES

Coronal Imaging Plane Prescribe coronal plane off of axial images parallel to supraspinatus muscle

Use axial sequence to orient the plane along the

supraspinatus tendon

- If the supraspinatus tendon is not well seen, you can either use the teres

minor tendon or the glenohumeral joint

- Cover from anterior portion of coracoid process to 1 slice posterior to the

humeral head.

- Oblique Sat band over chest

SAGITAL REFERENCE LINES

Sagittal Imaging Plane Prescribe sagittal plane off axial images with line parallel to bony glenoid. Image from bony glenoid through deltoid muscle.

Perpendicular to Coronal sequence

- Angle approximately parallel to GH joint on the Cor T2 sequence (use

Glenoid articulating surface to angle)

Cover from 1 slice out of humeral head to as far medial as slices allow

- Oblique Sat band over chest

- Cover from 1 slice out of humeral head to as far medial as the slices go

(to approx. the medial portion of the coracoid process)

Imaging the shoulder is optimal with a dedicated shoulder coil and careful patient positioning in external rotation with the shoulder as close as reasonably possible to the center of the magnet. Axial proton density, coronal oblique T2 fat sat and proton density, and sagittal oblique T2 provide an assessment of the rotator cuff, biceps, deltoid, acromio-clavicular joint, the gleno-humeral joint and surrounding large structures. If a labral injure is suspected, the optional fat sat gradient echo sequence (series 6) may be helpful or it may be necessary to bring the patient back for an MR shoulder arthrogram with intra-articular injection of dilute gadolinium.

Routine shoulder protocols are the most variable, but most include

SHOULDER MRI SEQUENCES

COR LOCALIZER

AXIAL LOCALIZER

COR Oblique T1

COR Oblique T2 TSE SPIR

SAG T1 TSE SPIR

SAG T2 FAT SAT

AX PD TSE SPIR (3 mm slices)

OPTIONAL:

AXIAL STIR

SAG STIR

COR STIR

AXIAL T1 SE SPIR

SAG T1 SE SPIR

COR T1 SE SPIR

AX PD TSE SPIR (3 mm slices) Particularly useful for assessment of the long head of the biceps tendon and subscapularis tendon. Glenohumeral ligaments, glenoid labrum and acramioclavicular joint are also assessed.

Coronal Fat-Sat PD spin echo (SE) Supraspinatus tendons and acromioclavicular joint are assessed. Superior labrum is also visualized well on this sequence.

COR Oblique T2 TSE SPIR Particularly useful to determine if the signal abnormalities in the supraspinatus tendons and superior labrum is truly due to degeneration or tear, and also to see if there is any fluid in the subacromian and subdeltoid bursa (which would be due to bursitis or rotator cuff tear). Bone edema like abnormalities also easily appreciated.

SAG T1 SE SPIR T1 sequence is useful to assess the bone marrow. Bone marrow replacing conditions are best evaluated with this sequence. Supraspinatus tendon impingement is also easily appreciated.

Sagittal Fat-Sat PD spin echo (SE) Useful to confirm findings appreciated on coronal plane and also useful for further assessment of the biceps tendon and its superior labral attachment.

Shoulder MR Arthrogram

Pre Gad: COR T1

COR T2 SPIR

AX T2 SPIR

Post Gad: AX T1 SPIR

COR T1 SPIR

SAG T1 SPIR

For labral pathology 2 mm cuts through the glenohumeral joint

Patient preparation:

Positioning: supine with arm at side and palm facing up. It is useful to tuck the hand under the hip to help keep the shoulder motionless. It is important to shift the patient to one side of the magnet so the shoulder being imaged is closer to the center, “sweet spot” of the magnet. This is especially helpful for fat saturation. Place a vitamin E capsule at the site of any mass or symptoms. A wide strap over the shoulder cinched down tight to the table can help reduce shoulder motion during breathing.

POSITIONING

- Supine

- Try to have shoulder neutral (external rotation is fine)

- Try to limit superior or inferior positioning of shoulder when compared to

the chest (IF THE SHOULDER IS MARKEDLY ANGLED, YOU CAN ANGLE THE

AXIAL IMAGES PERPENDICULAR TO THE GLENOHUMERAL JOINT)

- Try to place shoulder as close to isocenter in the bore of the magnet

- Place a sponge at the elbow and one supporting the hand and strap the

arm in place

Coil:

shoulder coil

- Large 4 channel flex coil for larger patient (make certain that coverage

has enough signal for the AC joint)

- Body matrix coil for an extremely large patient

Landmark: mid-coil

CORONAL PD FSE

CORONAL T2 FAT SAT FSE

SAG PD FAT SUPPRESSED FSE

SAG PD FSE

AXIAL PD FAT SAT FSE

AXIAL GRADIENT

SHOULDER ARTHROGRAM

Coronal oblique rotator cuff imaging

Shoulder Coronal Proton density FSE

The coronal plane is oblique, paralleling the central tendon of the Supraspinatus muscle. Occasionally, magic angle artifact can cause an increase in signal in the distal Supraspinatus tendon, mimicking a tear or tendonosis

Shoulder Coronal T2 fat suppresssed FSE:

T2 fat suppressed sequencing is used for sensitive detection of abnormal fluid of the distal Supraspinatus tendon. In contrast to an inversion recovery sequence, potential magic angle artifact is eliminated due to the long TE of theT2 sequence.

Magic angle artifact can occur on short TE sequences and can result in tendons/ligaments having erroneous areas of high T2 signal. Normally, transverse magnetization decay is enhanced (and therefore T2 is shortened) in non-random structures such as the parallel fibers of tendons and ligaments. But when tendons/ligaments are oriented at 55 degrees to the magnetic field, magnetization decay is hindered, increasing T2 signal intensity. Longer TE sequences are required to allow for full decay of transverse magnetization/T2 signal.

Sagital rotator cuff imaging

Sagittal Proton density FSE:

The sequence evaluates the acromial arch, including acromial inferior cortex, acromioclavicular joint, and coraco-acromioligament.

Shoulder Sagittal Proton density, fat sat FSE:

This sequence is a 'second look' at the distal rotator cuff tendons. The plane can also be angled obliquely to be more perpendicular to the tendons at insertion.

Axial glenoid labrum imaging

Shoulder Axial GRE: and Axial Proton density, fat suppressed FSE and

The sequences allow for evaluation of the labrum and glenohumeral ligaments, as well as the glenohumeral cartilage.

Shoulder arthrogram

Coronal Oblique T1 fat saturated

Axial T1 fat saturated

Sagital oblique T1 fat saturation

ABER T1 (abduction external rotation)

Although T1 fat suppressed post arthrogram sequences have excellent SNR and spatial resolution, their real utility in the shoulder is distention of the joint. Distention allows evaluation of structures that are often too crowded to see adequately, such as the labrum, glenohumeral ligaments and biceps anchor. Partial, articular surface (undersurface) tears of the distal supraspinatus tendons are also particularly well seen. An ABER (abduction external rotation) T1 sequence permits optimal visualization of the anterior inferior labral ligamentous complex (IGHL as it attaches to labrum), which may better define a Bankart lesion.