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brachial_plexus [2026/04/27 16:39] – [Scan Coverage and Planning] scottbrachial_plexus [2026/04/27 16:51] (current) – [Tips and Tricks] scott
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 =====Positioning===== =====Positioning=====
  
-Positioning for the brachial plexus exam is especially important. To ensure the nerves and forelimbs can be well assessed, both limbs should be positioned as __symmetrical__ as possible, and pulled __rostrally__ and well secured. Proper limb positioning will ensure that the peripheral brachial plexus nerves can be imaged closest to isocenter, compared slice-to-slice, and without excessive slice coverage. +Positioning for the brachial plexus exam is especially important. To ensure the nerves and forelimbs can be well assessed, both limbs should be positioned as __symmetrical__ as possible, and pulled __rostrally__ and well secured. Proper limb positioning will ensure that the peripheral brachial plexus nerves can be imaged closest to isocenter, compared slice-to-slice, and without excessive slice coverage. Typically dorsal recumbency is preferred, and any compatible coils that can be positioned over the elbows or sternum will help with SNR.
-Typically dorsal recumbency is preferred, and any compatible coils that can be positioned over the elbows or sternum will help with SNR. +
- +
-=====Anatomy===== +
- +
-The brachial plexus exam can be more difficult than a standard brain or spine exam, as there is more complex anatomy, different positioning requirements, and different scanning challenges.  A good sense of the anatomy is crucial to proper coverage and slice orientation. +
- +
-The brachial plexuses are bundles of nerves that originate from about C4/5 to T2/3 and extends into the forelimbs on both sides. When there is an injury or lesion in the brachial plexus, a patient may present with muscle atrophy or forelimb lameness without an orthopedic cause. Below are MIPs of the brachial plexus nerves in 3 planes. Keep in mind that the nerves extend deeper into the forelimb than visualized on these sequences, so the required coverage will be larger. +
- +
-{{::nervestir_sag_mip.gif?}}  {{::nerve_stir_ax_mip.gif?}}  {{::nerve_stir_dor_mip.gif?}}+
  
 =====Scan Coverage and Planning===== =====Scan Coverage and Planning=====
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   * Square matrix; ie 256x256 select a slightly lower resolution to save time and keep it square    * Square matrix; ie 256x256 select a slightly lower resolution to save time and keep it square 
   * Utilize higher bandwidth   * Utilize higher bandwidth
-  * If applicable to your system, try PROPELLER/BLADE+  * If applicable to your system, try PROPELLER/BLADE; pretty good for motion and also reduces flow artifact
  
 To reduce the effect of flow artifact: To reduce the effect of flow artifact:
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   * Check for symmetry; denervation changes are more easily spotted as fluid like intensity in muscles   * Check for symmetry; denervation changes are more easily spotted as fluid like intensity in muscles
   * Good fat saturation; use Dixon techniques whenever possible. If no Dixon is available, be sure to manually shim the area of interest   * Good fat saturation; use Dixon techniques whenever possible. If no Dixon is available, be sure to manually shim the area of interest
 +
 +===Fat Saturation===
 +
 +Fat saturation can be tricky in the cervical/plexus area due the uneven anatomy, presence of microchips, and large FOV's required. 
 +
 +{{::poorfatsat.png?400|}}
 +
 +  * Use Dixon techniques for fat saturation (Dixon, FLEX, IDEAL)
 +  * SPAIR/SPECIAL techniques may be a bit more homogenous if available
 +  * Manually shim to the area around the thoracic inlet
 +  * Position and scan close the isocenter
 +  * Use the smallest appropriate FOV