Analyze 7.5 image format

A variant (subset) of Analyze 7.5 image format is supported in TPC. Most of the image processing and analysis programs are able to read and write this format.

Image pixel data is stored in .img file, and header contents in .hdr file. Note that ECAT 6.3 images also have the extension *.img, and NIfTI dual file format image files consist of both *.img and *.hdr files.

Analyze files do not contain time information (PET frames). Therefore, corresponding SIF data should always be kept with dynamic Analyze images.

Converting image file formats

Program ImageConverter (contact Timo Laitinen) is available for converting image data between Analyze 7.5 and other formats. ImageConverter can optionally create SIF. In TPC, ImageConverter can be started from P:\bin\windows\ImageConverter.exe, elsewhere it can be downloaded from here.

Command-line tools

Additionally, ECAT 6.3 images and ECAT 7 image volumes can be converted to Analyze 7.5 images using program ecat2ana, and Analyze 7.5 images can be converted to ECAT 6.3 images or ECAT 7 image volumes using ana2ecat. Ecat2ana can create SIF if option -sif is used.

Analyze 7.5 images can be converted from big endian byte order (Intel PC) to big endian byte order (SUN Sparc, Motorola, PowerPC) and vice versa using anabyteo. Byte order can be set already during conversion with command line options.

Programs ecat2ana and ana2ecat, and all other programs that can read and write Analyze 7.5 images, may flip the image in x,y,z-directions by default. Alternatively, flipping may not be done in z-direction (planes). The default setting for command-line tools can be seen with program anafldef. This default behaviour of reversing or keeping the order of planes can be changed by defining an environment variable ANALYZE_FLIP with values Y or N. Note that creating or changing environment variables only has effect on shell or command prompt window that is started after the change. Image flipping during file conversions can be defined explicitly, not depending on the default behaviour, by using command line option -FLIP=Y or -FLIP=N.

Editing Analyze 7.5 image headers



References:

Robb RA, Hanson DP, Karwoski RA, Larson AG, Workman EL, Stacy MC. Analyze: a comprehensive, operator-interactive software package for multidimensional medical image display and analysis. Comput Med Imaging Graph. 1989; 13(6): 433–454.



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Created at: 2013-05-07
Updated at: 2017-04-11
Written by: Vesa Oikonen