QSM vs dopamine transporter PET: χ+ Mapping Shows Stronger Longitudinal Associations with Nigral Degeneration than Conventional QSM in Parkinson's Disease.
Authors
Affiliations (2)
Affiliations (2)
- From the Department of Radiology (C.Z., M.S., Q.Z., C.S., A.G.R., P.S., Y.W.),Weill Cornell Medicine, Cornell University, NewYork, NewYork, USA; Department of Radiology (C. Z., C.H.), Affiliated hospital of Xuzhou Medical University, Xuzhou, Jiangsu, P.R. China; Department of Electrical and Computer Engineering (M.S., A.G.R.), Cornell University, Ithaca, New York, USA; Department of Neurology (A.S.), Weill Cornell Medicine, New York-Presbyterian Hospital, New York, New York, USA and Department of Neurology (A.S.), Hospital for Special Surgery, NewYork, NewYork, USA.
- From the Department of Radiology (C.Z., M.S., Q.Z., C.S., A.G.R., P.S., Y.W.),Weill Cornell Medicine, Cornell University, NewYork, NewYork, USA; Department of Radiology (C. Z., C.H.), Affiliated hospital of Xuzhou Medical University, Xuzhou, Jiangsu, P.R. China; Department of Electrical and Computer Engineering (M.S., A.G.R.), Cornell University, Ithaca, New York, USA; Department of Neurology (A.S.), Weill Cornell Medicine, New York-Presbyterian Hospital, New York, New York, USA and Department of Neurology (A.S.), Hospital for Special Surgery, NewYork, NewYork, USA. [email protected].
Abstract
Iron accumulation in the substantia nigra (SN) is a hallmark of Parkinson's disease (PD). Quantitative susceptibility mapping (QSM) including source separation can generate maps of total susceptibility χ, paramagnetic or positive susceptibility [Formula: see text] likely dominated by tissue iron, and diamagnetic or negative susceptibility [Formula: see text] reflecting myelin and other sources. To compare χ, [Formula: see text], and [Formula: see text] for tracking SN longitudinal changes in PD and for correlating with dopaminergic PET measures and cognitive decline. This longitudinal study included 32 patients with PD (mean age, 65.88 ± 8.47 years) who underwent 3T MRI with 3D multi-echo gradient-echo (mGRE) and dynamic <sup>11</sup>C-N-(3-iodoprop-2E-enyl)-2β-carbomethoxy-3β-(4-methylphenyl) nortropane (PE2I) PET between August 2018 and April 2024. χ, [Formula: see text], and [Formula: see text] maps were reconstructed from mGRE data using the MEDI algorithm with susceptibility source separation. Dopamine transporter binding potential (BP) images were estimated from dynamic PET using a deep learning based kinetic model. Paired t tests, linear regression, and Pearson correlation analyses with Bonferroni correction were performed, with <i>P</i> < .05 considered significant. Both χ and [Formula: see text] from QSM revealed significant longitudinal susceptibility increases in the rostral and caudal SN (Bonferroni-corrected <i>P</i> < .05), with [Formula: see text] showing larger effect sizes (<i>t</i> = 9.99 vs 2.65 for the caudal SN). The left putaminal BP from PET significantly decreased at follow-up (<i>P</i> < .05). The longitudinal increase in [Formula: see text] within the rostral SN strongly correlated with the reduction in putaminal BP (<i>r</i> = - 0.60, <i>P</i> = .005, Bonferroni-corrected), whereas χ showed no significant association. Higher baseline [Formula: see text] values in the rostral and caudal SN predicted greater longitudinal cognitive decline (<i>P</i> = .01-.02, Bonferroni-corrected). Subregional analyses confirmed significant [Formula: see text] increases predominantly in the rostral-anterior SN. No significant change or correlation was observed with [Formula: see text] mapping at the SN. Positive susceptibility [Formula: see text] mapping showed larger longitudinal effect sizes for SN changes and stronger associations with dopaminergic PET decline and cognitive deterioration than to total susceptibility χ. These findings support [Formula: see text] mapping as a biologically informative MRI measure for the longitudinal assessment of SN changes in PD.