2381
Sensorimotor-Related Area Abnormalities in Amyotrophic Lateral Sclerosis: An Intravoxel Incoherent Motion Magnetic Resonance Imaging Study1Fujian Medical University Union Hospital, Fuzhou, China, 2Radiology, Fujian Medical University Union Hospital, Fuzhou, China
Synopsis
We conducted the first assessment of the sensorimotor-related areas(SMA) alterations in ALS using IVIM MRI and atlas-based analysis, which may provide useful information for localization of specific cortex and white matter(WM) tract damage in ALS. In grey matter areas (GM), ALS patients showed a reduction in f in the bilateral preSMA and SMA, while in WM areas, ALS patients exhibited an increase in D in a WM tract projecting to the right ventral premotor cortex(PMv). Correlation analysis revealed that the average D in this right PMv tract was negatively correlated to ALS disease severity.
Introduction
Amyotrophic lateral sclerosis (ALS) pertains to a progressive neurodegenerative disease; however, its etiology remains unclear. Neuroimaging studies have revealed structural and functional impairment of brain in ALS. Intravoxel incoherent motion (IVIM) MRI enables the separation of the intravoxel signals into microcirculatory effects and thermal diffusion effects using a bi-exponential model1. IVIM MRI modeled the IVIM signals into the pseudo-diffusion coefficient (D*), diffusion coefficient (D), and perfusion fraction (f)2. Specifically, D* represents the incoherent movement of blood occurring within microvasculature compartments, thereby providing information on blood speed3; D describes the random microscopic motion of intra-cellular and intercellular water molecules4; f represents the volume of blood flowing into the capillary2, which is positively correlated to cerebral blood volume (CBV) that is derived from dynamic contrastenhanced and dynamic susceptibility contrast MRI5;6. By analyzing these IVIM signals, we can gain better understanding of water movement in tissues. In the past few years, IVIM MRI has been applied to brain development4, cerebral small vessel disease7, and Alzheimer’s disease8. To the best of our knowledge, no IVIM MRI study in ALS has been reported to date. Here, we conducted the first assessment of the sensorimotor-related areas alterations in ALS using IVIM MRI and atlas-based analysis, which may provide useful information for localization of specific cortex and WM tract damage in ALS.Purpose
To investigate the microperfusion and water molecule diffusion alterations in sensorimotor-related areas in amyotrophic lateral sclerosis (ALS) using intravoxel incoherent motion (IVIM) magnetic resonance imaging.Methods
IVIM data were obtained from 43 ALS patients and 31 controls. This study employed the revised ALS Functional Rating Scale (ALSFRS-R) in evaluating disease severity. IVIM-derived metrics were calculated, including diffusion coefficient (D), pseudodiffusion coefficient, and perfusion fraction. Conventional apparent diffusion coefficient was also computed. Atlas-based analysis was conducted to detect between-group difference in these metrics in sensorimotor-related gray/white matter areas. Spearman correlation analysis was employed to establish correlation between various metrics and ALSFRS-R.Results
ALS patients had perfusion fraction (£ 10-3) reduction in the left presupplementary motor area (60.72 § 16.15 vs. 71.15 § 12.98, p = 0.016), right presupplementary motor area (61.35 § 17.02 vs. 72.18 § 14.22, p = 0.016), left supplementary motor area (55.73 § 12.29 vs. 64.12 § 9.17, p = 0.015), and right supplementary motor area (56.53 § 11.93 vs. 63.67 § 10.03, p = 0.020). Patients showed D (£ 10-6 mm2 /s) increase in a white matter tract projecting to the right ventral premotor cortex (714.20 § 39.75 vs. 691.01 § 24.53, p = 0.034). A negative correlation between D of right ventral premotor cortex tract and ALSFRS-R score was observed (r = -0.316, p = 0.039).Conclusions
These findings suggest aberrant microperfusion and water molecule diffusion in the sensorimotor-related areas in ALS patients, which are associated with motor impairment in ALS.Acknowledgements
The National Natural Science Foundation of China (Grant No. 82071900, 81671271, and 81974199) and Fujian Province Joint Funds for the Innovation of Science and Technology (Grant No. 2019Y9067 and 2018Y9027) supported this study.References
1. Dixon WT. Separation of diffusion and perfusion in intravoxel incoherent motion MR imaging: a modest proposal with tremendous potential. Radiology 1988; 168(2):566–567.
2. Paschoal AM, Leoni RF, Dos Santos AC, et al. Intravoxel incoherent motion MRI in neurological and cerebrovascular diseases. Neuroimage Clin 2018; 20:705–714.
3. Bihan DL, Turner R. The capillary network: a link between ivim and classical perfusion. 1992; 27(1):171178.
4. Yuan X, Yue C, Yu M, et al. Fetal brain development at 25-39 weeks gestational age: a preliminary study using intravoxel incoherent motion diffusion-weighted imaging. J Magn Reson Imaging 2019; 50 (3):899–909.
5. Wirestam R, Borg M, Brockstedt S, et al. Perfusion-related parameters in intravoxel incoherent motion Mr imaging compared with Cbv and Cbf measured by dynamic susceptibility-contrast Mr technique. Acta Radiologica 2001; 42(2):123–128.
6. Bisdas S, Braun C, Skardelly M, et al. Correlative assessment of tumor microcirculation using contrast-enhanced perfusion MRI and intravoxel incoherent motion diffusion-weighted MRI: is there a link between them? NMR Biomed 2014; 27(10):1184–1191.
7. Zhang CE, Wong SM, Uiterwijk R, et al. Intravoxel incoherent motion imaging in small vessel disease: microstructural integrity and microvascular perfusion related to cognition. Stroke 2017; 48(3):658–663. 2.
8. Bergamino M, Nespodzany A, Baxter LC, et al. Preliminary Assessment Of Intravoxel Incoherent Motion Diffusion-Weighted MRI (IVIM-DWI) Metrics in Alzheimer's Disease. J Magn Reson Imaging 2020; 52(6):1811– 1826.
Figures
