Shoulder MRI

Wednesday, October 19, 2016

Shoulder MRI - Planning Procedure

Before performing shoulder MRI besure that the patient is comfortable and explained to patient what is the procedure will be. Due to excessively loud gradient noise associated with some sequencses, ear plugs must be always provided to the patient to prevent hearing impairment.

Shoulder MRI are done to evaluate these common indications:
  • Evaluation of shoulder pain.
  • Diagnosis of impingement syndrome.
  • Suspected rotator cuff tear.
  • Evaluation of recurrent dislocation (instability).
  • Frozen shoulder syndrome.

Equipment use in Shoulder MRI

Shoulder array/small surface coil pair or multi-array/small flexible coil.
Immobilization pads and straps.
Ear plugs.

Patient Position - Shoulder MRI

The patient lies supine with the arms resting comfortably by the side. Slide the patient across the table to bring the shoulder under examination as close as possible to the center of the bore. Relax the shoulder to remove any upward ‘hunching’. The arm to be examined is strapped to the patient, with the thumb up (neutral position) and padded so that the humerus is horizontal. Place the coil to cover the humeral head and the anatomy superior and medial to it. If a surface or flexible coil is used, care must be taken to ensure that the flat surface of the coil is parallel to the Z axis when it is placed over the humeral head (Figure 1.1). Centre the FOV on the middle of the glenohumeral joint. Patient and coil immobilization are essential for a good result. Instruct the patient not to move the hand during sequences. The patient is positioned so that the longitudinal alignment light and the horizontal alignment light pass through the shoulder joint.

Suggested Protocol - MRI of Shoulder

Axial/Coronal incoherent (spoiled) GRE/SE/FSE T1

Acts as a localizer if three-plane localization is unavailable and ensures that there is adequate signal return from the whole joint. Medium slices/gap are prescribed relative to the horizontal alignment light so that the supraspinatus muscle is included in the image.

Axial GRE T2* weighted image of the shoulder
showing normal appearances
Axial localizer: I 0 mm to S 25 mm

Axial SE/FSE T2 or coherent GRE T2*

Thin slices/gap are prescribed from the top of the acromioclavicular joint to below the inferior edge of the glenoid (Figure 13.3). The bicipital groove on the lateral aspect of the humerus to the distal supraspinatus muscle is included in the image. The axial projection displays joint cartilage and glenoid labrum, intra-osseous changes associated with Hills–Sachs deformity, and the condition of muscles and tendons of the rotator cuff.


Coronal/oblique T1 weighted FSE through the
shoulder.

Coronal/oblique SE/FSE T1

Thin slices/gap are prescribed from the infraspinatus posteriorly to the supraspinatus anteriorally and angled parallel to the supraspinatus muscle. This is best seen on a superior axial view, but coverage is easier to assess on an axial image through the lower third of the humeral head. The superior edge of the acromion to the inferior aspect of the subscapularis muscle (about 1 cm below the lower edge of the glenoid), and the deltoid muscle laterally, and the distal third of the supraspinatus muscle medially are included on the image.
Coronal/oblique FSE T2 weighted image



Coronal/oblique SE/FSE T2 +/− chemical/spectral presaturation

Slice prescription as for Coronal/oblique T1.
Fat suppressed T2 weighted images clearly display muscle tears, trabecular injury, joint fluid and tendon tears. If SE is used chemical/spectral presaturation may not be necessary.

Coronal/oblique FSE T2 weighted image with
chemical/spectral presaturation.

Additional Sequences - Shoulder MRI


Sagittal/oblique SE/FSE T1

As for Coronal/oblique T1, except slices are prescribed from medial to the glenoid cavity to the bicipital groove laterally. The area from the distal portion of the joint capsule to the superior border of the acromion is included in the image
Sagittal/oblique/Axial FSE PD/T2 +/− chemical/spectral presaturation
This sequence provides a combination of anatomical display, tendon assessment, display of joint cartilage and sensitivity to trabecular damage.




Shoulder MR Arthrography
The technique is usually injecting a very dilute solution of Gadolinium to the shoulder joints.

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