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Influence of noise correlation in multiple‐coil statistical models with sum of squares reconstruction
Author(s) -
AjaFernández Santiago,
TristánVega Antonio
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23020
Subject(s) - noise (video) , electromagnetic coil , variance (accounting) , mathematics , explained sum of squares , statistics , least squares function approximation , correlation , signal (programming language) , nuclear magnetic resonance , physics , computer science , artificial intelligence , geometry , accounting , quantum mechanics , estimator , business , image (mathematics) , programming language
Abstract Noise in the composite magnitude signal from multiple‐coil systems is usually assumed to follow a noncentral χ distribution when sum of squares is used to combine images sensed at different coils. However, this is true only if the variance of noise is the same for all coils, and no correlation exists between them. We show how correlations may be obviated from this model if effective values are considered. This implies a reduced effective number of coils and an increased effective variance of noise. In addition, the effective variance of noise becomes signal‐dependent. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.