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.
- Liver, iron content, 761.121412
- Liver, MR, 761.121412
- Susceptibility studies
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging