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نمایش مقاله

Title:

Quantitative Assessment of Cerebral Oxygen Extraction and Oxygen Metabolism in Multiple Sclerosis Using Phase-Based MRI Susceptometry

Subject:

Clinical Applications of Brain Mappin

Presenter Author:
Name:	Asieh Fatemidokht

Author:
Name 1:	Asieh Fatemidokht - Corresponding - Presenter
Affiliation 1:	Department of Radiology, Faculty of Allied Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran

Name 2:	Keyvan Hassanzadeh
Affiliation 2:	Mojtaba Asadi Non-Profit Institute, Rafsanjan, Iran

Name 3:	Mohammad Ali Oghabian
Affiliation 3:	Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran

Name 4:	Mohammad Hossein Harirchian
Affiliation 4:	Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran

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Abstract

Original Research

introduction :

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disorder associated with complex alterations in cerebral tissue and vascular function. Assessment of cerebral oxygen metabolism may provide complementary quantitative information regarding these alterations. Phase-based MRI susceptometry enables noninvasive estimation of venous oxygen extraction fraction (OEF) from susceptibility-weighted imaging (SWI) and can therefore be used to investigate cerebral oxygen extraction in vivo. The present study evaluated OEF and cerebral metabolic rate of oxygen (CMRO₂) in patients with MS using susceptibility-based MRI analysis. The aim of this study was to quantitatively assess cerebral venous OEF in patients with MS and healthy participants and to evaluate differences in CMRO₂ across major cerebral venous structures.

Methods:

Fourteen patients with MS and healthy participants underwent MRI according to the study imaging protocol. Susceptibility-weighted imaging was analyzed using a phase-based susceptibility oximetry approach. OEF was estimated from phase differences between selected cerebral veins and the surrounding tissue. Five major cerebral venous structures were evaluated: the superior sagittal sinus (SSS), straight sinus (SS), vein of Galen, right internal cerebral vein (ICVR), and left internal cerebral vein (ICVL). The selected vessels included veins with different orientations relative to the main magnetic field. Cerebral blood-flow (CBF) measurements obtained from perfusion imaging were subsequently combined with OEF measurements to estimate CMRO₂. OEF and CMRO₂ values were evaluated between patients with MS and healthy participants for each venous territory.

Results:

The analysis demonstrated significant between-group differences in OEF in three of the five evaluated venous structures. Significant differences were observed in the SSS (p=0.0063), SS (p=0.013), and vein of Galen (p=0.020). In contrast, no statistically significant differences were observed in the ICVL (p=0.97) or ICVR (p=0.71). Thus, the OEF findings demonstrated a venous-territory-dependent pattern rather than a uniform alteration across all evaluated cerebral veins. CMRO₂ demonstrated statistically significant differences between patients with MS and healthy participants in all five evaluated venous territories. Significant differences were observed in the SS (p=0.0006), vein of Galen (p=0.00089), ICVL (p=0.003), ICVR (p=0.0037), and SSS (p=0.0086). The statistical findings for CMRO₂ were therefore consistent across all evaluated venous structures, in contrast to the more variable pattern observed for OEF.

Conclusion:

Phase-based MRI susceptometry allowed quantitative assessment of cerebral venous oxygen extraction in patients with MS. Significant OEF differences were identified in the SSS, SS, and vein of Galen, while the internal cerebral veins did not show statistically significant differences. In addition, CMRO₂ demonstrated significant differences across all five evaluated venous territories. These findings support the potential value of combining susceptibility-based OEF measurements with perfusion-derived CBF for quantitative assessment of cerebral oxygen metabolism in MS. Further studies with larger samples and comprehensive clinical data may help clarify the relationship between these imaging-derived metabolic parameters and clinical characteristics of MS.

Keywords:

Multiple sclerosis; oxygen extraction fraction; MRI susceptometry; susceptibility-weighted imaging; cerebral oxygen metabolism; cerebral blood flow