MRI of Chest and Shoulder Joint

MRI of Chest and Shoulder Joint

• MRI of chest and shoulder joint is presented by Dr. Hayder Jasim Taher, PhD of Medical Imaging.

Outline of Presentation

• Patient preparation and safety
• Precautions
• Contrast media:
  • Positive relaxation agents (T1 agents)
  • Negative relaxation agents (T2 agents)
  • Gadolinium

Anatomical Overview (Chest)

• The chest (thorax) is the region between the neck and abdomen, bounded by the bony thoracic cage.
• The upper boundary, the thoracic inlet, is formed by the first thoracic vertebra, first ribs, and the upper margin of the manubrium.
• The chest extends downwards to the thoracic outlet, marked by the diaphragm (between the inferior margin of the sternum and the upper lumbar vertebra).

Common Indications (Chest)

• Mediastinal mass (e.g., lymphoma, congenital cyst)
• Neurogenic lesions (e.g., thoracic meningoceles, malignant nerve sheath tumors)
• Differentiation between lymph nodes and vascular anomalies
• Assessment of vascular anomalies of the chest (e.g., thoracic aortic aneurysms) (using MRA)

MRI Procedure (Chest)

• Patient Position: Supine (head first), with feet-first orientation if claustrophobic.
• Coil setup: Torso-array coil.
• Scout slice placement (Axial):
  • Alignment: True axial
  • Coverage: From superior (thoracic inlet) to inferior (diaphragmatic crura), lateral (chest wall) to medial (spine), posterior (thoracic spinous processes) to anterior (sternum)
  • Information obtained: Showing contents of mediastinum, great vessels, and the heart.
• Scout slice placement (Coronal):
  • Alignment: True coronal
  • Coverage: Same as axial slice
  • Information obtained: Best plane for costophrenic angles and lung apices.

MRI Sequences (Chest)

• T1WI (FSE): Axial and coronal sections to provide detailed anatomical illustration of structures (heart, main vessels, mediastinum).
• T2WI (FSE): Axial and coronal sections to highlight tissue water content (inflammation, edema, abnormal tissue).
• Fat suppression sequences: To distinguish between fat-containing and non-fat tissues.
• DWI sequence: Assess tissue cellularity and identify chest lesions.
• Dyn-study + contrast (GAD-based): Evaluate tissue perfusion (vascular lesions, tumors).
• MRA: Visualize blood vessels for evaluation of vascular abnormalities (arteries and veins).

Anatomical Overview (Shoulder)

• The shoulder joint is formed by the articulation between the head of the humerus and the glenoid cavity (fossa) of the scapula.
• The large humeral head compared to the glenoid fossa leads to a wide range of movement but also instability.
• The glenoid fossa is deepened to reduce the disproportion of joint surfaces.

Indications for Shoulder MRI

• Diagnosis and evaluation of impingement syndrome and instability
• Frozen shoulder syndrome evaluation
• Rotator cuff injury
• Pectoralis tear

MRI Procedure (Shoulder)

• Patient Position: Supine (head first), offset left/right, bringing shoulder to magnet isocenter.
• Coil Setup: Multi-channel shoulder coil.
• Strap security: Ensure proper immobilization of the patient.
• Scout slice placement (Axial):
  • Alignment: Usually true axial (adjust angulation if humeral head position is abnormal).
  • Coverage: From acromioclavicular joint to surgical neck of humerus.
  • Acquisition: Superior to inferior
• Scout slice placement (Sagittal):
  • Alignment: Parallel to glenoid fossa.
  • Coverage: Entire deltoid muscle through the glenoid fossa.
  • Acquisition: Lateral to medial
• Scout slice placement (Coronal):
  • Alignment: Perpendicular to glenoid fossa, parallel to supraspinatus muscle.
  • Coverage: Subscapularis muscle through supraspinatus tendon.
  • Acquisition: Anterior to posterior

MRI Sequences (Shoulder)

• Different sequences (e.g., T1WI, T2WI, T2* GRE) with specific TR, TE, FA, ETL, and slice thickness are used to evaluate various aspects of the shoulder.