The measures used from Mendez: Segment length at dorsal column entry
To bring the spinal level positioning in the PAM50 space, linear scaling between length of Mendez and the length of pixels between C2 and L5 in the PAM50 was done.
However, the spinal segments length doesn't vary linearly along the spinal cord. Using the length between C2-L5 won't necessarly be accurate for all levels to get the position in the PAM50 space.
New spinal segment positions vs before on PAM50
Here are the different positions of the center of each segment with the updated spinal levels vs before:
Level | Mendez (Slices in I-->S) | Old (Slices in I-->S) | Difference
-- | -- | -- | --
C2 | 954 | 945 | 9
C3 | 927 | 927 | 0
C4 | 899 | 891 | 8
C5 | 868 | 857 | 11
C6 | 839 | 826 | 13
C7 | 812 | 794 | 18
C8 | 787 | 757 | 30
T1 | 760 | 713 | 47
T2 | 729 | 668 | 61
T3 | 695 | 622 | 73
T4 | 655 | 572 | 83
T5 | 608 | 522 | 86
T6 | 558 | 471 | 87
T7 | 507 | 417 | 90
T8 | 454 | 365 | 89
T9 | 403 | 310 | 93
T10 | 351 | 251 | 100
T11 | 301 | 194 | 107
T12 | 259 | 169 | 90
L1 | 221 | |
L2 | 188 | |
L3 | 162 | |
L4 | 137 | |
L5 | 114 | |
### Examples
Here are some examples:
**Mendez --> yellow; Old --> blue**
#### Segment C3
The center position is the same. We see the rootlet in the axial view.
#### Segment C4
**Axial view at the center of the segment for the new and old spinal segment**
--> Not much difference of the appearance of the spinal rootlet
#### Segment C5
**Axial view at the center of the segment for the new and old spinal segment**
--> We can better see the spinal rootlet in the old spinal segment file
#### Segment T6
#### Segment T10
### Suggestion
We need a surrogate measure to get the position of each spinal segment that we can relate to the PAM50.
Measures that relate the vertebrae to the spinal rootlets could be relevant here since we can position it for each level in the PAM50.
- Intervertebral foramen to rostral rootlet
- Intervertebral foramen to caudal rootlet
This would require identifying the intervertebral foramen on the PAM50 template
Description
We are currently working to update the spinal levels files in the PAM50 (see #3 ).
Philips Lab created updated spinal levels files : Philips Lab spinal level files from the Mendez (2021).
The measures used from Mendez: Segment length at dorsal column entry
To bring the spinal level positioning in the PAM50 space, linear scaling between length of Mendez and the length of pixels between C2 and L5 in the PAM50 was done.
However, the spinal segments length doesn't vary linearly along the spinal cord. Using the length between C2-L5 won't necessarly be accurate for all levels to get the position in the PAM50 space.
New spinal segment positions vs before on PAM50
Here are the different positions of the center of each segment with the updated spinal levels vs before:
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Level | Mendez (Slices in I-->S) | Old (Slices in I-->S) | Difference -- | -- | -- | -- C2 | 954 | 945 | 9 C3 | 927 | 927 | 0 C4 | 899 | 891 | 8 C5 | 868 | 857 | 11 C6 | 839 | 826 | 13 C7 | 812 | 794 | 18 C8 | 787 | 757 | 30 T1 | 760 | 713 | 47 T2 | 729 | 668 | 61 T3 | 695 | 622 | 73 T4 | 655 | 572 | 83 T5 | 608 | 522 | 86 T6 | 558 | 471 | 87 T7 | 507 | 417 | 90 T8 | 454 | 365 | 89 T9 | 403 | 310 | 93 T10 | 351 | 251 | 100 T11 | 301 | 194 | 107 T12 | 259 | 169 | 90 L1 | 221 | | L2 | 188 | | L3 | 162 | | L4 | 137 | | L5 | 114 | | ### Examples Here are some examples: **Mendez --> yellow; Old --> blue** #### Segment C3   The center position is the same. We see the rootlet in the axial view. #### Segment C4  **Axial view at the center of the segment for the new and old spinal segment**   --> Not much difference of the appearance of the spinal rootlet #### Segment C5  **Axial view at the center of the segment for the new and old spinal segment**   --> We can better see the spinal rootlet in the old spinal segment file #### Segment T6  #### Segment T10  ### Suggestion We need a surrogate measure to get the position of each spinal segment that we can relate to the PAM50. Measures that relate the vertebrae to the spinal rootlets could be relevant here since we can position it for each level in the PAM50. - Intervertebral foramen to rostral rootlet  - Intervertebral foramen to caudal rootlet  This would require identifying the intervertebral foramen on the PAM50 template