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

Division of Psychological & Social Medicine and Developmental Neurosciences
http://www.transdenlab.de/; http://www.uniklinikum-dresden.de/psm
+49 (0351) 458-5245
Universitätsklinikum Carl Gustav Carus
an der Technischen Universität Dresden
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http://www.uniklinikum-dresden.de
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