- MINC - N3
- An automated tool for correction of intensity nonuniformity in MRI data
- An artifact often seen in MRI is for the signal intensity to vary smoothly across an image. Variously referred to as RF inhomogeneity, shading artifact, or intensity on-uniformity, it is usually attributed to such factors as poor radio frequency (RF) field uniformity, eddy currents driven
by the switching of field gradients, and patient anatomy both inside and outside the field of view.
The perl script nu_correct implements a novel approach to correcting for intensity non-uniformity in MR data that achieves high performance without requiring supervision. By making relatively few assumptions about the data, the method can be applied at an early stage in an automated data analysis, before a tissue intensity or geometric model is available. Described as Non-parametric Non-uniform intensity Normalization (N3), the method is independent of pulse sequence and insensitive to pathological data that might otherwise violate model assumptions. To eliminate the dependence of the field estimate on anatomy, an iterative approach is employed to estimate both the multiplicative bias field and the distribution of the true tissue intensities. Preprocessing of MR data using N3 has been shown  to substantially improve the accuracy of anatomical analysis techniques such as tissue classification and cortical surface extraction.
- NIfTI-1 support
- John G. Sled
- source code
- How to get
- Current version
- Current version release date
- Open source
- see source code
- Available free of charge
- Technical publications
 J.G. Sled, A.P. Zijdenbos and A.C. Evans, "A non-parametric method for automatic correction of intensity non-uniformity in MRI data", in "IEEE Transactions on Medical Imaging", vol. 17, pp. 87--97, February 1998.
 J.G. Sled, "A Non-parametric Method for Automatic Correction of Intensity Non-uniformity in MRI Data", Master's Thesis, McGill University, Montreal, QC, May 1997 (available at http://www.bic.mni.mcgill.ca/~jgsled/thesis/)
 J.G. Sled, A.P. Zijdenbos and A.C. Evans, "A Comparison of Retrospective Intensity Non-uniformity Correction Methods for MRI", Information Processing in Medical Imaging, pp. 459-464, 1997
- Applications publications
- Other information
- FAQ for N3
- intensity nonuniformity, MRI artifact
- cygwin on Windows, HPUX, IRIX, Linux, MacOS, SunOS, UNIX
- IATR listing last updated
- 23 Sep 2005
There are no user reviews for this tool.