MRI Procedures for Chest and Shoulder

MRI of Chest and Shoulder Joint

• This presentation covers MRI procedures for chest and shoulder joint assessments.
• The presenter is Dr. Hayder Jasim Taher, a PhD in Medical Imaging.
• The presentation outlines patient preparation, safety precautions, contrast media (positive/negative relaxation agents and gadolinium).

Anatomical Overview (Chest)

• The chest (or thorax) is the region between the neck and abdomen, enclosed by the bony thoracic cage.
• The upper boundary (thoracic inlet) is formed by the first thoracic vertebra, the first ribs, and the superior margin of the manubrium.
• Inferiorly, the chest extends to the thoracic outlet, defined by the diaphragm, which spans between the inferior margin of the sternum and the upper lumbar vertebra.

Common Indications (Chest)

• Assessing mediastinal masses (e.g., lymphoma, congenital cysts).
• Evaluating neurogenic lesions (e.g., thoracic meningoceles, malignant nerve sheath tumors).
• Differentiating between lymph nodes and vascular anomalies.
• Assessing vascular anomalies of the chest (in conjunction with MRA), such as thoracic aortic aneurysms.

MRI Procedure (Chest)

• Patient Position: Supine (head first). Patients with claustrophobia may prefer a feet-first orientation.
• Coil Placement: Torso-array coil.
• Scout Slice Placement for Axial Slice: True axial alignment, superior to inferior (thoracic inlet to diaphragmatic crura), lateral to medial (chest wall), and posterior to anterior (thoracic spinous processes to sternum). This helps to illustrate mediastinum contents, great vessels, and the heart.
• Axial Localizer for Coronal Slice: True coronal alignment. This plane visualizes the costophrenic angles and lung apices.

MRI Techniques (Chest)

• T1WI (FSE): Provides detailed anatomical information of chest structures (heart, main vessels, mediastinum).
• T2WI (FSE): Visualizes tissue water content, helping to identify areas of inflammation and edema.
• Fat Suppression sequences: Differentiates fat-containing from non-fat tissues.
• DWI sequence: Assesses tissue cellularity. Helpful for lesions.
• Dynamic Study + Contrast (GAD-based): Evaluates tissue perfusion with slice thickness of 5 mm and characterizes lesions based on their vascularity (useful for vascular lesions and tumors).
• MRA: A vascular study using a 1-2mm slice thickness to show blood vessels (main arteries and veins) and detects vascular abnormalities.

Anatomical Overview (Shoulder Joint)

• The shoulder joint is a combination of articulation between the humeral head and glenoid fossa (scapula).
• The humeral head is bigger than the glenoid fossa, thereby providing a wide range of motion in the shoulder joint.
• A deeper glenoid fossa, created by additional structures, helps reduce the disparity in size between the two articular surfaces to minimize instability.

Indications (Shoulder Joint)

• Diagnosing and assessing impingement syndrome and instability.
• Diagnosing frozen shoulder syndrome.
• Evaluating rotator cuff injuries.
• Evaluating pectoralis tears.

MRI Procedure (Shoulder Joint)

• Patient Position: Supine with head first, offset as needed. The shoulder area should be as close to the magnet center as possible.
• Coil Placement: Multi-channel shoulder coil.
• Scout Slice Placement for Axial Slice: True axial alignment. Angulation in the supraspinatus muscle area may be necessary to correct for unusual positioning on the shoulder. Coverage from the acromioclavicular joint to the humeral neck.
• Scout Slice Placement for Sagittal Slice: Lateral to medial slice acquisition, image orientation should be parallel within the glenoid fossa. Image coverage should be thorough.
• Scout Slice Placement for Coronal Slice: Anterior-to-posterior slice acquisition. Slice alignment parallel to the glenoid fossa, as well as the supraspinatus muscle. Image coverage thorough.

MRI Sequences (Shoulder Joint)

• Different sequences (e.g., T1WI, T2WI, etc.) are utilized to provide various information on the structure and function of the tissues.