Thoracic Spine MR Imaging Scan

Thursday, September 29, 2016

Thoracic Spine - Planning and Positioning

When performing MR imaging of the thoracic spine radiologic technologist on duty must be aware that patients with cord trauma may be severely disabled and in great pain. The examination should obviously be undertaken as speedily as possible under these circumstances. Due to excessively loud gradient noise associated with some sequences, ear plugs must always be worn to the patient to avoid hearing impairment.

Thoracic MR imaging is done to study these common indications:

  • Thoracic disc disease
  • Thoracic cord compression
  • Visualization of a MS plaque in the thoracic cord
  • Thoracic cord tumour
  • To visualize the inferior extend of cervical spine

Equipment use – Thoracic MR imaging

  • Posterior spinal coil or multi-coil array spinal coil.
  • Pe gating leads if required
  • Ear plugs

Patient Positioning – Thoracic MR imaging

In the examination couch the patient is supine with spinal coil extending from the top of the shoulders to the lower costal margin to ensure total coverage of the thoracic spine and conus. The longitudinal alignment light lies in the midline of the patient, and the horizontal alignment light passes through the center of the coil, which correspond approximately to the level of the fourth thoracic vertebra. Pe gating leads are attached if required.

Suggested Protocol – Thoracic Spine MR Scan

Sagittal / Coronal SE / FSE T1 or coherent T2

This is the localizer if three-plane localization is unavailable. The coronal or sagittal planes may be used.

Coronal Localizer

It is a medium size slices approximately 40 mm posterior and 30 mm anterior and are prescribe relative to the vertical alignment light, from the posterior aspect of the spinous processes to the anterior border of the vertebral bodies. The area from the seventh cervical vertebra to conus is included in the image.

Sagittal Localizer:

This are medium slices and are prescribed on either side of the longitudinal alignment light, from the left to the right lateral border of the vertebral bodies. This include from 7th cervical spine C7 to the conus is included on the image.

thoracic spine
Sagittal FSE T1 weighted midline slice through
the thoracic spine.

Sagital T1 – SE / FSE

A thin slices and prescribes on both side of the longitudinal alignment light, from the left to the right lateral borders of the vertebral bodies – unless the paravertebral areas are needed. This include the C7 to the conus.

Sagittal SE / FSE T2 or coherent GRE T2

Slice and planning is like as for sagittal T1.

thoracic spine mri
Sagittal FSE T2 weighted midline slice through
the thoracic cord.

Axial or Oblique SE / FSE T1 or coherent gradient echo T2

The slices are angled so that they are parallel to the disc space or becomes perpendicular to the lesion under examination. If vertebral disc is under examination, three or four slices per level is usually done. For larger lesions such as tumor or syrinx, thicker slices are scan to the lesions and a small area above and below are necessary.

thoracic spine
Sagittal FSE T2 weighted midline slice through
the thoracic spine showing slice prescription boundaries and
orientation for axial imaging of the conus.

Additional Sequences

Sagittal / Axial / Oblique SE / FSE T1 +/- contrast
This is usually done for evaluation of the conus and other cord lesions.

thoracic spine
Axial/oblique FSE T2 weighted images through the
thoracic cord.

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