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library:thoracolumbar_spine [2025/03/10 17:17] – [Axial Plane] scottlibrary:thoracolumbar_spine [2025/06/18 02:54] (current) – scott
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-=====Thoracolumbar Spine MRI=====+======Thoracolumbar Spine MRI======
  
  
  
-====Scan Coverage and Planning====+=====Scan Coverage and Planning=====
  
 The thoracolumbar spine (TL Spine) is the more complex area of the CNS to scan clinically, as the coverage is much broader since both the full thoracic spine and lumbar spine are included. There are various protocol for scanning the TL spine that can vary quite a bit from clinician to clinician, so it is best to establish clinician preference ahead of time. The most important image to acquire accurately is the sagittal, since this is where pathology is initially identified, and the image from which axial sequences are planned. Poor quality sagittal images will hinder identifying pathology, which can greatly extend scan and anesthesia time. There are two primary paths for TL spine scanning in regards to sagittal imaging: Whole Spine or Separate. The thoracolumbar spine (TL Spine) is the more complex area of the CNS to scan clinically, as the coverage is much broader since both the full thoracic spine and lumbar spine are included. There are various protocol for scanning the TL spine that can vary quite a bit from clinician to clinician, so it is best to establish clinician preference ahead of time. The most important image to acquire accurately is the sagittal, since this is where pathology is initially identified, and the image from which axial sequences are planned. Poor quality sagittal images will hinder identifying pathology, which can greatly extend scan and anesthesia time. There are two primary paths for TL spine scanning in regards to sagittal imaging: Whole Spine or Separate.
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 ====Axial Plane==== ====Axial Plane====
  
-On a mid-sagittal image, plan axial slices perpendicular to the spinal cord. Unlike the cervical spine, the angle for the intervertebral disc and the spinal cord are very well aligned and can be considered equivalent. There are two variations of axial acquisitions, Single Stack or Multi Stack. This is largely up to clinician preference, but there are some good practices to consider. +On a mid-sagittal image, plan axial slices perpendicular to the spinal cord. Unlike the cervical spine, the angle for the intervertebral disc and the spinal cord are very well aligned and can be considered equivalent. There are two variations of axial acquisitions, **Single Stack or Multi Stack**. This is largely up to clinician preference, but there are some good practices to consider. 
  
-  * With disc disease, extrusions tend to be fairly localized, though in rare cases may extend cranially or caudally. Multi Stack is often appropriate and more time efficient for this, especially when assessing a large number of discs. It is good practice to use 3-7 slices, centered on the disc, for each disc. where pathology is suspected, it is also good practice to use enough axial slices to extend to the mid-body of the vertebrae above and below the suspected disc extrusion to catch any disc material not well visualized on a sagittal image. On the Multi Stack plan shown below, note the angle required at the LS junction; significant slice overlap will cause artifact, and in some cases may need to be consolidated into a Single Stack. +  * **Multi Stack**: With disc disease, extrusions tend to be fairly localized, though in rare cases may extend cranially or caudally. Multi Stack is often appropriate and more time efficient for this, especially when assessing a large number of discs. It is good practice to use 3-7 slices, centered on the disc, for each disc. where pathology is suspected, it is also good practice to use enough axial slices to extend to the mid-body of the vertebrae above and below the suspected disc extrusion to catch any disc material not well visualized on a sagittal image. On the Multi Stack plan shown below, note the angle required at the LS junction; significant slice overlap will cause artifact, and in some cases may need to be consolidated into a Single Stack. 
-  * With spinal cord pathology such as FCE or myelopathy, disc assessment is less important. Single Stack is most appropriate in this situation. It is good practice to acquire the axial stack from normal cord-to-normal cord if possible.+  * **Single Stack**: With spinal cord pathology such as FCE or myelopathy, disc assessment is less important. Single Stack is most appropriate in this situation. It is good practice to acquire the axial stack from normal cord-to-normal cord if possible.
  
 {{:library:lspineaxplansinglestack.png?600|}}  {{:library:lspineaxplanmultistack.png?600|}} {{:library:lspineaxplansinglestack.png?600|}}  {{:library:lspineaxplanmultistack.png?600|}}
 +
 +====Dorsal Plane====
 +
 +On a mid sagittal image, plan the slices parallel with the spinal cord. Slices should extend from the aorta dorsally up to the spinous process of the vertebrae. Where there is noted pathology, adjust the angle of the slices a bit for the best visualization.
 +
 +{{:library:lspinedorplan.png?600|}}  {{:library:lspinedornormal.png?600|}}
 +
 +====Tips and Tricks====
 +
 +===Optional Sequences==
 +
 +There is a wide scope of pulse sequences that will find utility in the thoracolumbar spine, depending on patient size, clinical question, and pathology. Some are used frequently even though they are not included in the Typical Protocol above, others are good to know about for specific clinical scenarios.
 +
 +==Myelography==
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 +
 +{{:library:3dmyeloprofile.png?600|}}  {{:library:2dhastemyeloprofile.png?600|}}
 +
 +==T2* Weighting==
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 +{{:library:mergespineprofile.png?600|}}
 +
 +==T2 Weighting==
 +
 +Most modern scanners will have an option for a Driven Equilibrium pulse sequence that incorporates and additional -90 degree pulse to 'flip back' the transverse magnetization along the Z axis. This has the effect of speeding up longitudinal recovery even for very long T1 tissues like CSF, meaning that it isn't necessary to have very long TR's. When performing a T2 weighted sequence with this modification, TR can be as low as 1500ms in some cases, while maintaining high signal from CSF. On a GE scanner this option is known as **Fast Recovery FSE (FR-FSE)** and can be found in most GE spine protocols. On a Siemens scanner, this is known as **Restore**, and may be a check box on the contrast tab, or may be found in Siemens spine protocols. These options can shorten scan time, especially when only a few slices are needed, as is the case with sagittal spine imaging.
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