Thanks a lot for your reply
I'm using ANALYZE format
fslhd output is:
sizeof_hdr 348
data_type
db_name
extents 0
session_error 0
regular a
hkey_un0
dim0 4
dim1 181
dim2 217
dim3 181
dim4 1
dim5 0
dim6 0
dim7 0
vox_units
cal_units
unused1 0
datatype 2
bitpix 8
pixdim0 2.000000
pixdim1 1.000000
pixdim2 1.000000
pixdim3 1.000000
pixdim4 0.000000
pixdim5 0.000000
pixdim6 0.000000
pixdim7 0.000000
vox_offset 0.0000
funused1 1.0000
funused2 0.0000
funused3 0.0000
cal_max 0.0000
cal_min 0.0000
compressed 0
verified 0
glmax 255
glmin 0
descrip
aux_file
orient 0
originator Z
origin1 90
origin2 126
origin3 72
generated
scannum
patient_id
exp_date
exp_time
hist_un0
views 0
vols_added 0
start_field 0
field_skip 0
omax 0
omin 0
smin 0
smin 0
file_type ANALYZE-7.5
file_code 0