Institute of Neurology, UCL

MRreg Image Registration and Processing Package

1. General Description
MRreg is a complete software environment for the registration and analysis of brain MRI data. It was developed primarily for the automatic quantification of changes in serial MRI volume scans of the brain, in particular to quantify signal changes in low-grade brain lesions (see illustration below). However, MRreg is also useful for the following purposes (among others): The precision and accuracy of the registration in MRreg have been fully validated, with a registration accuracy for test objects of 0.02mm and a registration 'consistency' of 0.06mm in living subjects (please consult the 1998 papers in Medical Physics and Medical Image Analysis in the publications list below).

MRreg consists of the main following components:

MRreg offers most standard image display features, eg intensity windowing, zooming, etc, plus: MRreg is accompanied by an automatic brain extraction tool, called Exbrain.

*MRreg has facilities for saving and retrieving manually drawn traces, region growing seeds and threshold levels, and for the automatic calculation of areas and volumes.
2. Example
The following illustrates the quantification of signal changes in a lesion in a series of five volume scans.


The top left image is a slice from the baseline volume scan. The second column contains slices from from subsequent scans after registration. The third column contains slices from the difference volume, after intensity matching. The fourth column contains the segmented differerences, with red representing significant signal decrease and green, signal increase. The latter is obtained by automatic thresholding of the structured part of the difference image and comparison with an anatomical map of changes and artefacts in normal subjects (derived from serial scan pairs of 20 normal subjects).


3. Main Publications
(as of 29/01/99)

Lemieux L, Wieshmann UC, Moran NF, Fish DR, Shorvon SD, "The Detection and Significance of Subtle Changes in Mixed-signal Brain Lesions by Serial Scan Matching and Spatial Normalisation," Medical Image Analysis 2(3): 227-242 (1998). Web version (Oxford University Press)

Lemieux L and Barker GJ, "Measurement of Small Inter-scan Fluctuations in Voxel Dimensions in Magnetic Resonance Images Using Registration," Medical Physics 25(6): 1049-1054 (1998).

Moran NF, Lemieux L, Maudgil DD, Kitchen ND, Fish DR, Shorvon SD, "Analysis of temporal lobe resections in MR images," Epilepsia 40(8): 1077-1084 (1999).

Tebartz van Elst L, Woermann FG, Lemieux L, Trimble, MR, "Association between Left Amygdala Volume and Depression Score in Patients with Temporal Lobe Epilepsy - a MRI Volumetric Study," Biological Psychiatry, accepted for publication.

Tebartz van Elst L, Woermann FG, Lemieux L, Trimble, MR, "Affective aggression in patients with temporal lobe epilepsy - a quantitative magnetic resonance imaging study of the amygdala," Brain, accepted for publication.

Wieshmann UC, Woermann FG, Lemieux L, Free SL, Bartlett PA, Smith SJM, Duncan JS, Stevens JM and Shorvon SD, "The Development of Hippocampal Sclerosis: a Serial MRI Study over a 58 Month Period in a Patient After Status," Epilepsia 38: 1238-1241 (1997).

Lemieux L, "Segmentation and Estimation of Gaussian Noise and Structure in Difference Images of Co-registered MR Imaging Scan Pairs," Radiology, 205(P): 167 (1997).

Lemieux L, "Automatic Estimation of the Random Noise Level in Difference Images from Matched Brain Scans Based on the Segmentation of Structure," Proc. ISMRM 1998: 2082.

 4. Contact
Louis Lemieux, PhD
Lecturer in Physics
Epilepsy Research Group
Institute of Neurology, UCL
33 Queen Square,
London WC1N 3BG
United Kingdom

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This page was last modified on 29/01/99 by LL.