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MR susceptometry: an external-phantom method for measuring bulk susceptibility from field-echo phase reconstruction maps.

R W Holt·P J Diaz·J L Duerk·E M Bellon
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Abstract

A novel method for estimating the susceptibility of an object by using the magnetic resonance (MR) imaging field distortions in an external-reference water bath next to the object is described. The field measurement was obtained with a phase reconstruction from a gradient-echo acquisition. A field model of an arbitrary object in a static magnetic field was discretely calculated from geometry determined from the magnitude reconstruction. Least-squares estimation yields the susceptibility of the object. Required (and proven) assumptions include validity of superposition, object homogeneity, negligible higher-order field terms, field-model accuracy, geometric-model accuracy, and correlation of gradient-echo phase to field distortion. MR susceptometry estimation of phantoms yielded susceptibility estimates that correlated well with known values (r > .9975). This MR susceptometry method is a first step toward quantitation of iron levels through MR imaging phase information in patients with iron overload.

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AlgorithmsArtifactsChloridesFerric CompoundsFourier AnalysisImage EnhancementImage Processing, Computer-AssistedIronLatexLinear ModelsMagnetic Resonance ImagingMagneticsModels, StructuralModels, TheoreticalReproducibility of ResultsSensitivity and SpecificityWaterJournal ArticleResearch Support, Non-U.S. Gov't

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R W Holt, P J Diaz, J L Duerk, E M Bellon. MR susceptometry: an external-phantom method for measuring bulk susceptibility from field-echo phase reconstruction maps.. https://doi.org/10.1002/jmri.1880040612

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