Differences

This shows you the differences between two versions of the page.

--- brachial_plexus [2026/04/27 16:37] – [Tips and Tricks] scott
+++ brachial_plexus [2026/04/27 16:51] (current) – [Tips and Tricks] scott
@@ Line 3: / Line 3: @@
 =====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=====
+=====Scan Coverage and Planning=====
-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.
+==== A note on Localizers====
-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=====
+When planning out your localizer images, be sure to use a LARGE FOV so that the forelimbs are well demonstrated, positioning can be checked, and coil extents can be seen. Use a LOT of slices to cover all the anatomy; you want to be able to find the shoulder joints, elbows,  and sternum on all three planes.
 ====Sagittal Plane====
 For brachial plexus scout images, add more slices on all planes to cover sternum to spine dorsally, shoulder to shoulder sagittal, and C3 to T3 axially. On the axial and dorsal scout imaging, plan the slices parallel to the center of the spinal cord. On the sagittal scout image, center the FOV on C6/7.
@@ Line 48: / Line 42: @@
   * Square matrix; ie 256x256 select a slightly lower resolution to save time and keep it square
   * 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:
@@ Line 63: / Line 57: @@
   * 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
+===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