Chest/Thoracic Spine

• The indications for thoracic imaging are to identify or exclude disease processes like osteoporosis, tuberculous osteomyelitis, scheuermann's disease, neoplasm, and metabolic disorders.
• Another indication for thoracic imaging is to identify or exclude anatomic abnormalities such as scoliosis, rib fractures, spine fractures, ligamentous injury, and dislocations.
• The routine radiographic views of the thoracic spine are anteroposterior and lateral.
• AP view of thoracic spine

  
• The pedicles on an AP view of the thoracic spine should be about 20 mm from each other. This allows us to determine the width of the vertebral foramen.
• T2 MRI Sagittal View

  
• The vertebral body should be consistently shaded throughout an axial CT. Areas of lucency are indicative of osteoporosis.
• CT coronal view of thoracic spine

  
• The anterior column of the spine holds the anterior ligament, the anterior two-thirds of the vertebral body, and the annulus fibrosis.
• The middle column of the spine holds the posterior third of the vertebral body and the posterior ligament.
• The posterior column of the spine holds the posterior ligament complex and vertebral arch structures.
• The spatial relationship of the three spinal columns should hold true whether the image is in flexion or extension.
• When interpreting a CT consider alignment, bone density, canal space, disc integrity, and soft tissue structures.
• When interpreting an MRI consider alignment, bone density, canal space, disc integrity, and soft tissue structure.
• CSF has high signal intensity on T2 MRI.
• Discs have intermediate signal intensity on T1 MRI.
• Discs have high signal intensity on T2 MRI.
• Sagittal view of MRI

  
• Scoliosis is named for the convex side of the curve.
• The most frequently seen curve is the right convex thoracic curve.
• The major curve in the right thoracic curve is from T4-6 to T11-L1.
• The right thoracolumbar curve extends from T4-6 to L2-4.
• A left lumbar curve extends from T11-12 to L5.
• A left lumbar, right thoracic curve is a double major curve. Both curves have equal prominence.
• Often, secondary or minor curves are seen above and below the major curve. These are compensatory and initially nonstructural curves that aid in balancing the spine and keeping to eyes oriented to the horizontal.
• Identify the curve

  A) Right thoracic

  
• Identify the curve

  A) right thoracolumbar

  
• Identify the curve

  A) left lumbar

  
• Identify the curve

  A) double major right thoracic left lumbar

  
• The basic radiographic assessment of scoliosis includes erect posteroanterior to assess deformity in the coronal plane and erect lateral to asses deformity in the sagittal plane.
• Flexible nonstructural curves will reverse or straighten upon side bend to the convexity.
• Rigid, nonstructural curves will not be altered during side bending.
• Kyphoscoliosis designates curves present in both the coronal and sagittal planes.
• Curve size of scoliosis may be measured with the pedicle method. This identifies how far the convex side pedicle has rotated toward midline.
• 0 on the pedicle method indicates no rotation.
• 1+ on the pedicle method indicates the pedicle has moved 1/3 towards the midline.
• 2+ on the pedicle method indicates the pedicle has moved 2/3 of the way.
• 3+ on the pedicle method indicates that the pedicle is at midline.
• 4+ on the pedicle method indicates that pedicle is beyond midline.
• The cobb method is the most common radiographic measurement of scoliosis.