Reliability of quantitative magnetic susceptibility imaging metrics for cerebral cortex and major subcortical structures

Among the evaluated ROI-QSM metrics, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>μ</mml:mi> <mml:mi>all</mml:mi></mml:msub> <mml:annotation>${{{{\mu}}}_{{\mathrm{all}}}}$</mml:annotation></mml:semantics> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>μ</mml:mi> <mml:mi>abs</mml:mi></mml:msub> <mml:annotation>${{{{\mu}}}_{{\mathrm{abs}}}}$</mml:annotation></mml:semantics> </mml:math> estimates were less reliable, whereas separating positive and negative values (using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>μ</mml:mi> <mml:mi>p</mml:mi></mml:msub> <mml:mo>,</mml:mo> <mml:mspace></mml:mspace> <mml:msub><mml:mi>μ</mml:mi> <mml:mi>n</mml:mi></mml:msub> <mml:mo>,</mml:mo> <mml:mspace></mml:mspace> <mml:msub><mml:mi>μ</mml:mi> <mml:mi>wp</mml:mi></mml:msub> <mml:mo>,</mml:mo> <mml:mspace></mml:mspace> <mml:msub><mml:mi>μ</mml:mi> <mml:mi>wn</mml:mi></mml:msub> </mml:mrow> <mml:annotation>${{{{\mu}}}_{\mathrm{p}}},\ {{{{\mu}}}_{\mathrm{n}}},\ {{{{\mu}}}_{{\mathrm{wp}}}},\ {{{{\mu}}}_{{\mathrm{wn}}}}$</mml:annotation></mml:semantics> </mml:math> ) improved the reproducibility within, and the comparability between, subjects, even when reducing the slice thickness. These preliminary findings may offer valuable insights toward standardizing ROI-QSM metrics across different patient cohorts and imaging settings in future clinical MRI studies.