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dear freesurfer experts
comparing the results of longitudinal vs. crosssectional preprocessing for single time point participants I have noticed that there are some quite substantial differences (>5% for some sub cortical regions). I wonder whether this is normal, or whether I should suspect that I am using some wrong setting. the differences are there both when using freesurfer 5.3 and freesurfer 7.1.
I have always used the flag: -nuintensitycor-3T (our scanner is a 3 Tesla one)
I would say that I more often have smaller volumes in the longi preprocessing (80% of the cases), but I haven't checked this systematically.
This are the first 5 regions from the aseg.stats file:
FS5 CROSS # ColHeaders Index SegId NVoxels Volume_mm3 StructName normMean normStdDev normMin normMax normRange 1 4 4772 4772.4 Left-Lateral-Ventricle 45.4073 12.8146 24.0000 92.0000 68.0000 2 5 133 132.6 Left-Inf-Lat-Vent 51.9800 10.2799 28.0000 77.0000 49.0000 3 7 13488 13488.1 Left-Cerebellum-White-Matter 91.1006 5.2419 37.0000 106.0000 69.0000 4 8 57562 57561.8 Left-Cerebellum-Cortex 72.0094 8.7033 24.0000 96.0000 72.0000 5 10 8428 8428.3 Left-Thalamus-Proper 94.7674 7.1110 52.0000 111.0000 59.0000
FS5 LONGI
# ColHeaders Index SegId NVoxels Volume_mm3 StructName normMean normStdDev normMin normMax normRange 1 4 4542 4541.9 Left-Lateral-Ventricle 42.8623 13.5582 22.0000 94.0000 72.0000 2 5 131 130.5 Left-Inf-Lat-Vent 50.6667 11.1812 23.0000 81.0000 58.0000 3 7 13576 13576.1 Left-Cerebellum-White-Matter 86.1990 4.5161 40.0000 100.0000 60.0000 4 8 57615 57614.7 Left-Cerebellum-Cortex 68.7623 8.6206 17.0000 92.0000 75.0000 5 10 8658 8658.2 Left-Thalamus-Proper 91.2531 6.7374 52.0000 107.0000 55.0000
FS7 CROSS
# ColHeaders Index SegId NVoxels Volume_mm3 StructName normMean normStdDev normMin normMax normRange 1 4 4871 5297.0 Left-Lateral-Ventricle 43.9799 11.8868 24.0000 91.0000 67.0000 2 5 145 202.9 Left-Inf-Lat-Vent 53.7310 10.0009 28.0000 79.0000 51.0000 3 7 14703 15351.7 Left-Cerebellum-White-Matter 86.7391 5.5097 35.0000 100.0000 65.0000 4 8 57694 57174.0 Left-Cerebellum-Cortex 68.6875 9.0320 29.0000 95.0000 66.0000 5 10 8674 8354.1 Left-Thalamus 89.9416 8.1369 40.0000 107.0000 67.0000
FS7 longi
# ColHeaders Index SegId NVoxels Volume_mm3 StructName normMean normStdDev normMin normMax normRange 1 4 4898 5154.3 Left-Lateral-Ventricle 41.0488 12.0309 22.0000 79.0000 57.0000 2 5 165 214.4 Left-Inf-Lat-Vent 52.3939 11.2687 27.0000 84.0000 57.0000 3 7 14655 15364.2 Left-Cerebellum-White-Matter 83.1088 4.9509 39.0000 98.0000 59.0000 4 8 58759 58163.3 Left-Cerebellum-Cortex 65.8093 8.7269 25.0000 90.0000 65.0000 5 10 8757 8542.9 Left-Thalamus 85.7984 6.8821 47.0000 102.0000 55.0000
thanks for any hint, and of course please let me know in case I should provide more informations!
fabio bernardoni
Dr. Fabio Bernardoni wiss. Mitarbeiter
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