Dicom diff - a diff-like tool for comparing DICOM files
Author: Jiří Keller, M.D., Ph.D.
This SW is a result of the research funded by the project Nr. LO1611 with a financial support from the MEYS under the NPU I program.
For more detailed manual, please refer to readme.txt file.
DICOM is a well established medical image communication and storage format. From the user's perspective, each DICOM file consists of a header and medical data (typically image such as CT or MRI, but can be anything from spectroscopic curve to endoscopic screenshots or photos from your vacation). In reality, there is no difference between header and data in DICOM standard, as it contains only key-value pairs (image data is just another "value"). In DICOM world, the "keys" are called tags and they are referenced by (Group,Element) pair as there is makes handling more than 2000 items in the DICOM 3 standard easier. Each Group and Element is a hexadecimal two bytes number. The whole list is listed in part PS3.6 of the DICOM standard (caled Data Dictionary) - see (http://dicom.nema.org/medical/dicom/current/output/html/part06.html). Standard tags have even Group numbers, odd Group numbers are reserved for so called "private" tags, which are typically vendor-specific and may contain a lot of interesting information, unfortunately in most of the cases undocumen- ted. In Standard DICOM Dictionary, tags such as patient name (0010,0010), sex (0010,0040), age, weight, medical device which produced image and many others are defined. And, by the way, your image is stored in PixelData tag which is (7fe0,0010).
Dicomdiff (or didiff) is tool inspired by GNU diff, which compares two files line by line. Our tool compares DICOM tags between two DICOM files or a DICOM file and ASCII dump (see readme.txt for details).
There are three basic output modes:
- basic diff-like output (values from each files on separate lines)
- "first file value" and "the corresponding value" with tag and one value per line
- CSV output with tag and both values on one line
CSV (comma separated values) format can be very handy as it can be easily processed using any Office package or an automatic script (eg. awk).