AN AUTOMATIC CHANGE DETECTION METHOD IN DIFFUSIONWEIGHTED IMAGES: APPLICATION TO MULTIPLE SCLEROSIS. BOISGONTIER Hervéa,b, NOBLET Vincenta, HEITZ Fabricea, RUMBACH Lucienb,c, CATTIN Françoised and ARMSPACH JeanPaulb
Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection, LSIIT, UMR CNRSULP 7005, Bd Sébastien Brant, BP 10413, F67412 Illkirch Cedex, France. b Laboratoire d'Imagerie de Neurosciences Cognitives, LINCIPB, Faculté de médecine, UMR CNRSULP 7191, 4 Rue Kirschleger, F67085 Strasbourg Cedex, France c Service de Neurologie, d Service de Radiologie, CHU Minjoz, F25030 Besançon Cedex, France
[email protected]strasbg.fr a
Abstract Magnetic Resonance Imaging (MRI) plays an important role in Multiple Sclerosis (MS) diagnosis and for monitoring the evolution of the disease over time [1]. The advent of new quantitative MRI techniques and the constant improvement in spatial resolution yield an increasing amount of 3D image data, whose interpretation is a tedious and errorprone task. The automatic analysis of subtle changes between MRI scans is an important tool for assessing disease evolution over time. Methods have already been proposed to detect changes in serial conventional MRI [2]. However, few works address change detection in diffusionweighted imaging, which is a promising technique for monitoring neurodegenerative diseases. We propose an automatic method for change detection between scalar images diffusionweighted, with application to the followup of multiple sclerosis lesion evolution. The method relies on the generalized likelihood ratio test [3], while accounting for the nonstationarity of noise that corrupts these images. Validation has been conducted by simulating lesion appearances in real data. The results show that accounting for the nonstationarity of noise allows to significantly reduce the number of false detections. Further work will also consider change detection directly on tensor images. Such automatic methods for change detection in diffusionweighted imaging may provide an objective way for characterizing the evolution of MS lesions, in particular for those located in the normalappearing white matter, and a useful tool for studying MS consequences on anatomical and functional brain connectivity.
References [1] Y. Ge, “Multiple sclerosis: The role of MR imaging”, American Journal of Neuroradiology, vol. 27, no. 6, pp. 1165–1176, JuneJuly 2006. [2] M. Bosc, F. Heitz, J.P. Armspach, I. Namer, D. Gounot, and L. Rumbach. “Automatic change detection in multimodal serial MRI: application to multiple sclerosis lesion evolution.” NeuroImage, 20(2):643656, July 2003. [3] S. M. Kay, Fundamentals of statistical signal processing: detection theory, PrenticeHall, Inc., Upper Saddle River, NJ, USA, 1998.