LOW RESOLUTION SUSCEPTIBILITY MAPPING IN THE ESTIMATION OF IRON CONTENT IN DEEP GREY MATTER OF BRAIN AT 3 TESLA

Abstract

Objective: The objective of this study is to determine the effect of low resolutionin the estimation of iron content in deep grey matter of brain usingquantitative susceptibility mapping.

Methodology: Six females with mean age 43.16, S.D= 20, age range (23-66) and 13 males with mean age 28.92 + 8.14 were scanned with 3D SWIsequence at 3 Tesla (Trio-Seimens, Erlangen, Germany). The caudate nucleus,red nucleus, globus pallidus, putamen, white matter, thalamus and substantianigra of brain were drawn manually based on their anatomical locationsin Signal Processing in Nuclear Magnetic Resonance (SPIN). Magnitude andphase images of high resolution (HR) (0.5x0.5x2 mm3) were processed in SPINusing collapsing parameter to generate the low resolution (LR) (1x1x2 mm3)susceptibility mapping. Data was analyzed using paired t-test.

Results: A strong linear correlation (R2=0.99, p ≤ 0.05) was found betweenthe susceptibilities of Deep Grey Matter (DGM) at low resolution versus highresolution which showed the consistency of susceptibility at both resolution.When the susceptibilities in ppb of DGM were correlated with iron content(mgFe/100g), a positive correlation was found with R-saqure (R2=0.67, p ≥0.05 at HR, R2=0.66, p ≥ 0.05 at LR). The slope of the above linear correlationwas consistent with the equivalent susceptibility trend at low and high resolution QSM.

Conclusion: Linear correlation between susceptibility and iron content at HRand LR has demonstrated that low resolution QSM holds the consistency ofsusceptibility and does not affect the estimation of iron content in deep greymatter of brain.