Differences in CSA

Hello guys!
I am running CSA analysis for different studies, but recently I came across with a potential issue; when I analyze some nii the majority of the CSA in the cervical spinal cord are in magnitude of 10s (ie C3 45) but with one study I am finding magnitudes of 100 (ie 900). Can someone give me some orientation of what is happening?

Hi @enriquegf,

Thank you for reaching out. Could you please clarify what you mean by “10s (ie C3 45)”? CSA are in mm^2, so I am not sure what you meant here.

I’m also confused by “magnitudes of 100 (ie 900)”. What is the unit here? And what does “ie 900” mean?

I am sorry for this barely legible explanation. I upload both screenshot from what I ve done.

Captura de Pantalla 2021-01-27 a la(s) 9.38.41 Captura de Pantalla 2021-01-27 a la(s) 9.38.51

I obtained results from one study in magnitude of hundreds, but in the same patient in a previous study it is in magnitude of tens.

It is probably caused by your NIfTI headers, which are corrupted (ie: the qform/sform does not reflect the actual physical dimensions). If you upload an example image and segmentation that yields those CSAs I can have a look.

ok! here is the .nii of this patient from which I obtained this results.
Thank very very much! I am just beginning to try SCT as a neurologist m20.nii.gz (2.4 MB)

hum, the header looks good-- could you please also upload the segmentation you used to compute the CSA?

Of course! here it is

m20_seg_labeled_discs.nii.gz (77.7 KB) m20_seg_labeled.nii.gz (84.3 KB) m20_seg.nii.gz (4.8 KB)

I’m not sure what you did, but results look OK on my end:

VertLevel MEAN(area)
8 44.05825885019590
7 48.594102619341700
6 53.87744611037150
5 63.68126638238550
4 57.07686534077420
3 57.532144223958000

CSV output: csa.csv (2.9 KB)

I used this command (SCT v5.1.0):

sct_process_segmentation -i m20_seg.nii.gz -vertfile m20_seg_labeled.nii.gz -vert 3:8 -perlevel 1

I will re-run it to try to look for what error I might have.

If you could write the exact syntax you typed it is helpful for us to debug. Usually we ask users to copy/paste the syntax and output from the Terminal.

Hi @enriquegf, just following up to see if you still have an issue, or if we can close this ticket?