A maximum entropy method for MEG source imaging

Conference · Tue Dec 31 00:00:00 EST 1996

OSTI ID:513282

Khosla, D ^[1]; Singh, M ^[2]

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1. Univ. of Southern California, Los Angeles, CA (United States)
2. House Ear Institute, Los Angeles, CA (United States)

The estimation of three-dimensional dipole current sources on the cortical surface from the measured magnetoencephalogram (MEG) is a highly under determined inverse problem as there are many {open_quotes}feasible{close_quotes} images which are consistent with the MEG data. Previous approaches to this problem have concentrated on the use of weighted minimum norm inverse methods. While these methods ensure a unique solution, they often produce overly smoothed solutions and exhibit severe sensitivity to noise. In this paper we explore the maximum entropy approach to obtain better solutions to the problem. This estimation technique selects that image from the possible set of feasible images which has the maximum entropy permitted by the information available to us. In order to account for the presence of noise in the data, we have also incorporated a noise rejection or likelihood term into our maximum entropy method. This makes our approach mirror a Bayesian maximum a posteriori (MAP) formulation. Additional information from other functional techniques like functional magnetic resonance imaging (fMRI) can be incorporated in the proposed method in the form of a prior bias function to improve solutions. We demonstrate the method with experimental phantom data from a clinical 122 channel MEG system.

• OSTI ID: 513282
• Report Number(s): CONF-961123-; CNN: Grant NIA-NIH P50AG05142; Grant NIH NS-53213; TRN: 97:003193-0357
• Resource Relation: Conference: Institute of Electrical and Electronic Engineers (IEEE) nuclear science symposium and medical imaging conference, Anaheim, CA (United States), 2-9 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 IEEE nuclear science symposium - conference record. Volumes 1, 2 and 3; Del Guerra, A. [ed.]; PB: 2138 p.
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
55 BIOLOGY AND MEDICINE
BASIC STUDIES
99 MATHEMATICS
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
ELECTROENCEPHALOGRAPHY
IMAGE PROCESSING
ENTROPY
MAGNETIC FIELDS
PHANTOMS
DIPOLE MOMENTS
CALCULATION METHODS
NUCLEAR MAGNETIC RESONANCE