Mean Apparent Propagator MRI Is Better Than Conventional Diffusion Tensor Imaging for the Evaluation of Parkinson’s Disease: A Prospective Pilot Study

Abstract

Background and Purpose: Mean apparent propagator (MAP) MRI is a novel diffusion imaging method to map tissue microstructure. The purpose of this study was to evaluate the diagnostic value of the MAP MRI in Parkinson's disease (PD) in comparison with conventional diffusion tensor imaging (DTI). Methods: 23 PD patients and 22 age-and gender-matched healthy controls were included. MAP MRI and DTI were performed on a 3T MR scanner with a 20-channel head coil. The MAP metrics including mean square displacement (MSD), return to the origin probability (RTOP), return to the axis probability (RTAP), and return to the plane probability (RTPP), and DTI metrics including fractional anisotropy (FA), and mean diffusivity (MD), were measured in subcortical gray matter and compared between the two groups. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic performance of all the metrics. The association between the diffusion metrics and disease severity was assessed by Pearson correlation analysis. Results: For MAP MRI, the mean values of MSD in the bilateral caudate, pallidum, putamen, thalamus and substantia nigra (SN) were higher in PD patients than in healthy controls (p FDR ≤ 0.001); the mean values of the zero displacement probabilities (RTOP, RTAP, and RTPP) in the bilateral caudate, pallidum, putamen and thalamus were lower in PD patients (p FDR < 0.001). For DTI, only FA in the bilateral SN was significantly higher in PD patients than those in the controls (p FDR < 0.001). ROC analysis showed that the areas under the curves of MAP MRI metrics (MSD, RTOP, RTAP, and RTPP) in the bilateral caudate, pallidum, putamen and thalamus (range, 0.85-0.94) were greater than those of FA and MD of DTI (range, 0.55-0.69) in discriminating between PD patients and September 2020 | Volume 12 | Article 563595 Le et al. MAP MRI in PD healthy controls. RTAP in the ipsilateral pallidum (r = −0.56, p FDR = 0.027), RTOP in the bilateral and contralateral putamen (r = −0.58, p FDR = 0.019; r = −0.57, p FDR = 0.024) were negatively correlated with UPDRS III motor scores. Conclusion: MAP MRI outperformed the conventional DTI in the diagnosis of PD and evaluation of the disease severity.

White matter microstructural impairments in amyotrophic lateral sclerosis: A mean apparent propagator MRI study

“…Participants were scanned on a Siemens Prisma 3.0 T scanner with 64-channel head coil. Diffusion images were acquired with a spin-echo echo-planar imaging sequence, using a full q -space Cartesian grid sampling scheme, which has been applied in previous MAP-MRI studies ( Jiang et al, 2021 , Le et al, 2020 , Mao et al, 2020 ). For each participant, 100 diffusion-weighted images were acquired at following b -values (direction number): 0 (2), 350 (6), 600 (12), 1000 (8), 1400 (6), 1650 (24), 2000 (24), 2700 (12), and 3000 (6) s/mm 2 .…”

Age and sex effects on advanced white matter microstructure measures in 15,628 older adults: A UK biobank study

“…NODDI is a multi-compartment model that separately models restricted, hindered, and free water diffusion, which are thought to correspond to intra-cellular, extra-cellular, and isotropic water components, respectively (Zhang et al, 2012); NODDI may thus provide microstructure metrics more closely linked to specific aspects of the cellular environment than single-shell models (Zhang et al, 2012), although some recent work suggests the assumptions underlying NODDI's specificity may not always be met (Jelescu & Budde, 2017;Jelescu et al, 2020). MAP-MRI is a diffusion propagator-based multi-shell model that estimates the diffusion patterns of water molecules without a priori assumptions about the underlying tissue, which may allow for the detection of more subtle microstructure alterations (Fick et al, 2016;Le et al, 2020;Ning et al, 2015;Ozarslan et al, 2013).…”

Age and Sex Effects on Advanced White Matter Microstructure Measures in 15,628 Older Adults: A UK Biobank Study

“…NODDI is a multi-compartment model that separately models restricted, hindered, and free water diffusion, which are thought to correspond to intra-cellular, extra-cellular, and isotropic water components, respectively (Zhang, Schneider, Wheeler-Kingshott, & Alexander, 2012); NODDI may thus provide microstructure metrics more closely linked to specific aspects of the cellular environment than single-shell models (Zhang et al, 2012), although some recent work suggests the assumptions underlying NODDI’s specificity may not always be met (Jelescu & Budde, 2017; Jelescu, Palombo, Bagnato, & Schilling, 2020). MAPMRI is a diffusion propagatorbased multi-shell model that estimates the diffusion patterns of water molecules without a priori assumptions about the underlying tissue, which may allow for the detection of more subtle microstructure alterations (Fick, Wassermann, Caruyer, & Deriche, 2016; Le et al, 2020; Ning et al, 2015; Ozarslan et al, 2013).…”