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Hello,

I had the problem already with FS 7.2.0, but since it also occurs in FS 8.1.0, which I currently have installed on UBUNTU 20.24, an answer would be helpful. I am fully aware that FS and Synthseg do not provide exactly the same results when calculating the volumes for the same T1 scan with FS and Synthseg. E.g when I calculate a T1 3D 1mm ISO scan and a FLAIR 3D 2mm ISO scan of the same person both with Synthseg, I also fully understand that the results will not be exactly the same here either. However, what I do not understand is that the results for sub-volumes sometimes deviate by a factor of 1000? I have attached a small table below: row 1 Synthseg T1 scan, row 2 Synthseg FLAIR scan, row 3 FS T1 scan same subject. E.g. for "left lateral ventricle," the Synthseg FLAIR and FS results are about the same, but the Synthseg T1 does not match by a factor of 1000. For "left inferior lateral ventricle," the Synthseg FLAIR result is too large. Where do these deviations come from? Is it a unit problem??? I do not understand what is behind it. These deviations occur in all individuals in this manner.

Thank you for your help, Jürgen

subject

total intracranial

left cerebral white matter

left cerebral cortex

left lateral ventricle

left inferior lateral ventricle

left cerebellum white matter

left cerebellum cortex

left thalamus

left caudate

left putamen

left pallidum

3rd ventricle

4th ventricle

brain-stem

left hippocampus

left amygdala

csf

left accumbens area

Syn= 02_t1_5_13

1581149.5

234530.16

279514.53

28584312

515.05

15703237

62220.02

5994828

3766241

4605884

1485176

1864659

2365228

23305277

3743831

1692543

258776.8

679.45

Syn= 02_flair_5_13

1540067.8

237580.17

278995.16

26533.9

462551

14112386

64456.68

6460912

3999.81

4585682

1717103

1535.82

1356496

26397467

3787048

1596163

211639.08

720396

fs= 02_t1.5.3

1558777.000000

212518.500000

248086.368363

30058.0

1061.2

16326.6

57684.7

5877.0

3879.4

4342.9

1751.2

2113.8

2982.3

20526.8

4015.2

1763.8

374287.9

539.0

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