MNI Automated Linear Registration Package


DESCRIPTION
-----------

In both diagnostic and research applications, the interpretation of
magnetic resonance (MR) images of the human brain is facilitated when
different data sets can be compared by visual inspection of equivalent
anatomical planes.  Quantitative analysis with pre-defined atlas
templates often requires the initial alignment of atlas and image
planes.  Unfortunately, the axial planes acquired during separate
scanning sessions are often different in their relative position and
orientation, and these slices are not coplanar with those in the
atlas.
 
A completely automatic method has been developed, based on
multi-scale, three dimensional (3D) cross-correlation, to register a
given volumetric data set to an average MRI brain (n > 300) aligned
with the Talairach stereotaxic coordinate system.  Once the data set
is resampled by the transformation recovered by the algorithm, atlas
slices can be directly super-imposed on the corresponding slices of
the resampled volume (see below).  The use of such a standardized
space also allows the direct comparison, voxel-to-voxel, of two or
more data sets brought into stereotaxic space.

A Perl script (mritotal) implements the multi-resolution fitting
strategy that has been used to map more than 500 brains into
stereotaxic space at the Montreal Neurological Institute.  At the
heart of this procedure is minctracc, the program that automatically
finds the best linear transformation to map one volumetric data set
(stored in MINC format, see below) on to another.  The program uses
optimization over a user selectable number of parameters to identify
the best (according to a user-selected objective function)
transformation mapping voxel values of the first data set into the
second.

A paper describing the automatic linear stereotaxic registration
procedure has appeared in:

   D.  L.  Collins, P.  Neelin, T.  M.  Peters and A.  C.  Evans,
   Automatic 3D Inter-Subject Registration of MR Volumetric Data 
	in Standardized Talairach Space,
   Journal of Computer Assisted Tomography, 18(2) p192-205, 1994

The nonlinear registration procedure is described in:

   DL Collins, CJ Holmes, TM Peters and AC Evans,
   Automatic 3D model-based neuro-anatomical segmentation
   Human Brain Mapping, 3(3) p 190-208, 1995


INSTALLING MNI_AUTOREG
----------------------

The install directions for this package are contained in the files
INSTALL.quick and INSTALL.  What follows here are instructions for 
installing *prerequisite* software.

You can obtain a copy of the latest version of the MNI_AutoReg
software from:

   http://packages.bic.mni.mcgill.ca/tgz

Look for a file named mni_autoreg-x.yy.tar.gz (where x.yy is the release
number).
 
MNI_AutoReg requires that both the MINC and netCDF packages be built and
installed first.  The MINC file format is a highly flexible medical
image file format built on top of the netCDF generalized data format.
You should be able to get them both from 

   http://packages.bic.mni.mcgill.ca/tgz

If you prefer, you can get netCDF from its home site, the Unidata Program
Centre at the University Corporation for Atmospheric Research:

   ftp://unidata.ucar.edu/pub/netcdf

You will also need a recent version of Perl 5; Perl 5.002 or later is
required.

You can always find the latest version of Perl at at any mirror of the
Comprehensive Perl Archive Network (CPAN)

   http://www.perl.com/


In addition to Perl itself, you will need the Getopt::Tabular module.
This is also available at

   http://www.cpan.org/

The model used for stereotaxic registration is based on the 305 brain
average MRI volume created at the Montreal Neurological Institute.
Because of its size, this model is *not* included with the MNI_AutoReg
package.  But, it too is available from

   http://pacakges.bic.mni.mcgill.ca/tgz/mni_autoreg_model-x.y.tar.gz

The version of mni_autoreg_model is NOT tied to the version of
mni_autoreg.  Choose the highest numbered version.


USING MNI_AUTOREG
-----------------

The primary scripts for registration are:

   mritotal:      the script that calls mincblur and minctracc to achieve
                  stereotaxic registration

   mritoself:     intra-subject registration


Other scripts or programs installed are:

   autocrop:      for extracting and manipulating bounds of a MINC file

   make_model:    generate appropriate blurred and subsampled images
                  required for `mritotal'

   make_phantom:  generate ellipsoid or rectangular phantom images

   mincbbox:      extract bounding box of image

   mincblur:      a program for volumetric convolution with a Gaussian 
                  blurring kernel

   mincchamfer:   compute a Chamfer distance transform of an image

   minctracc:     a program to estimate the transformation required 
                  for registration

   xfmtool:       perform miscellaneous operations on transform (.xfm) files


Some of these ship with manual pages, and all respond to `-help'.  For further
information, use the source, Luke!  We'd be extremely please to receive
documentation updates for any of the above!


PORTABILITY
-----------

We have gone to great lengths to ensure that MNI AutoReg compiles and
runs correctly on a variety of Unix and Unix-like systems.  However,
we only have ready access to Linux, IRIX, and SunOS systems;
successful use of the package on other systems is not necessarily
assured.  (For that matter, its successful use anywhere is not assured
-- you get what you pay for!  See the COPYING file.)

That said, if you have trouble building and/or testing the package,
we'd like to hear about it.  But just telling us "it didn't build" or
"a test failed" is not enough -- ideally, you would provide us with a
detailed breakdown of your system configuration (architecture,
operating system and OS version, compiler and compiler version, C
library -- including header files -- and its version), and a
comprehensive explanation of what went wrong and how we can fix it
without interfering with portability to any *other* system.  We don't
expect that every bug report will have this amount of information, but
keep in mind that that's the ideal to strive for.

Please do not complain of portability problems unless you have first
made sure that your C compiler and library (including header files!)
are ANSI compliant.


CONFIGURATION AND PROTOCOL FILES
--------------------------------

Mritotal requires two external files to run.  These are the
configuration file (mritotal.cfg) and protocol file (default is
mritotal.default.cfg, but you can specify others using the -protocol
option).  If you follow all the above instructions, then these files
will be correctly customized and installed for your site.  If things
go wrong, though, you should know the following:

   * The directory where the configuration and protocol file(s) are
     installed defaults to /usr/local/etc/mni_autoreg.  If you change this
     (ie. move the files after installing them) *without* rerunning "configure"
     and "make", then mritotal will not be able to find them.
     That's because "make" modifies mritotal so that it points
     to the directory for config files.
 
   * The location of the model files is specified in the configuration
     file.  You should check that the directory where you installed
     the model files (which is specified in the Makefile for the
     mni_autoreg_model package) is the same as the directory 
     given in mritotal.cfg (using the -modeldir option).  For
     instance, if mni_autoreg_model/Makefile has the line:

        MODELDIR    = /data/avgbrain1/brain/images/model

     then mni_autoreg's perl/mritotal.cfg should have the line:

        -modeldir /data/avgbrain1/brain/images/model

   * If you find it necessary to make a new protocol for your site's
     data (for instance, if your MRI data consistently covers
     considerably more than the brain, but the heuristic used by the
     default protocol doesn't work -- see the mritotal man page for
     more information), then you should copy and change the default
     protocol file.  For instance, you might want to call the protocol
     "mysite" -- in that case, copy mritotal.default.cfg to
     mritotal.mysite.cfg, and be *sure* to edit mritotal.cfg so that
     it uses the new protocol by default.  That is, make sure it has
     "-protocol mysite" instead of "-protocol default".

     That said, please notify Louis Collins <[email protected]> if
     the heuristics used by the default protocol don't work for your
     data.

Good luck!  Please let us know if anything goes wrong with the
installation or testing:

Louis Collins                       Steve Robbins
<[email protected]>           <[email protected]>
tel:(514)-398-1726,1996 

McConnell Brain Imaging Center   
NeuroImaging Laboratory		 
Montreal Neurological Institute  
3801 University St.
Montreal, Quebec.  H3A 2B4	  

Fax:(514)-398-8948