Quantitative susceptibility mapping (QSM) as a means to measure brain iron? A post mortem validation study

By C. Langkammer, Ferdinand Schweser, N. Krebs, Andreas Deistung, W. Goessler, E. Scheurer, K. Sommer, Gernot Reishofer, K. Yen, F. Fazekas and 2 more. NeuroImage, 2012

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Quantitative susceptibility mapping (QSM) is a novel technique which allows determining the bulk magnetic susceptibility distribution of tissue in vivo from gradient echo magnetic resonance phase images. It is commonly assumed that paramagnetic iron is the predominant source of susceptibility variations in gray matter as many studies have reported a reasonable correlation of magnetic susceptibility with brain iron concentrations in vivo. Instead of performing direct comparisons, however, all these studies used the putative iron concentrations reported in the hallmark study by Hallgren and Sourander (1958) for their analysis. Consequently, the extent to which QSM can serve to reliably assess brain iron levels is not yet fully clear. To provide such information we investigated the relation between bulk tissue magnetic susceptibility and brain iron concentration in unfixed (in situ) post mortem brains of 13 subjects using MRI and inductively coupled plasma mass spectrometry. A strong linear correlation between chemically determined iron concentration and bulk magnetic susceptibility was found in gray matter structures (r = 0.84, p < 0.001), whereas the correlation coefficient was much lower in white matter (r = 0.27, p < 0.001). The slope of the overall linear correlation was consistent with theoretical considerations of the magnetism of ferritin supporting that most of the iron in the brain is bound to ferritin proteins. In conclusion, iron is the dominant source of magnetic susceptibility in deep gray matter and can be assessed with QSM. In white matter regions the estimation of iron concentrations by QSM is less accurate and more complex because the counteracting contribution from diamagnetic myelinated neuronal fibers confounds the interpretation.

Subfields: Insect Science, Radiology, Nuclear Medicine and Imaging

View Paper: https://www.semanticscholar.org/paper/f6340f7773c0628893679fff0bfdaabde5d58414

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In Radiology, Nuclear Medicine and Imaging

Citations in the corpus

Overview of quantitative susceptibility mapping (2017, neutral): “k → 2 0 B@ 1 CA δ otherwise 8>>>>< >>>>: [19]”
Myelin and iron concentration in the human brain: A quantitative study of MRI contrast (2014, background): “, 2009) and thence to quantitative susceptibility mapping (QSM), which is better able to visualize the iron distribution in brain tissue (Langkammer et al., 2012; Schäfer et al., 2012).”
Toward in vivo histology: A comparison of quantitative susceptibility mapping (QSM) with magnitude-, phase-, and R2⁎-imaging at ultra-high magnetic field strength (2013, positive): “Variations in magnetic susceptibility and R2⁎ in white matter may be explained by different contributions of iron (Langkammer et al., 2010, 2012a) and myelin (Hwang et al., 2010; Jellison et al., 2004; Laule et al., 2006, 2008).”
A method for estimating and removing streaking artifacts in quantitative susceptibility mapping (2014, neutral): “022 (ppm) (Langkammer et al., 2012).”