Jiani Hu1, Yimin Shen1, Lara M Fahmy2,3, Satish Krishnamurthy4, Jie Li4, Li Zhang2, Yongsheng Chen5, E Mark Haacke6, Quan Jiang7,8. 1. Department of Radiology, Wayne State University, Detroit, MI, USA. 2. Department of Neurology, Henry Ford Health System, 2799 W Grand Blvd, Detroit, MI, 48202, USA. 3. Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, USA. 4. Department of Neurosurgery, Upstate Medical University, Syracuse, NY, USA. 5. Department of Neurology, Wayne State University, Detroit, MI, USA. 6. Department of Radiology, Wayne State University, Detroit, MI, USA. nmrimaging@aol.com. 7. Department of Neurology, Henry Ford Health System, 2799 W Grand Blvd, Detroit, MI, 48202, USA. qjiang1@hfhs.org. 8. Department of Neurology, Wayne State University, Detroit, MI, USA. qjiang1@hfhs.org.
Abstract
OBJECTIVES: The current understanding of cerebral waste clearance (CWC) involves cerebrospinal fluid (CSF) participation but lacks convincing evidence for the direct participation of the parenchymal vascular system. The objective of this study was to evaluate the role of the parenchymal vascular system in CSF tracer clearance in rats. METHODS: We used superparamagnetic iron oxide-enhanced susceptibility-weighted imaging (SPIO-SWI) and quantitative susceptibility mapping (QSM) methods to simultaneously study 7 T MRI signal changes in parenchymal veins, arteries, and their corresponding para-vascular spaces in 26 rats, following intra-cisterna magna (ICM) infusion of different CSF tracers (FeREX, Ferumoxytol, Fe-Dextran) to determine the amount of tracer in the artery and vein quantitatively. RESULTS: We observed that the parenchymal venous system participated in CSF tracer clearance following ICM infusion of different MRI tracers with different concentrations of iron. Parenchymal venous participation was more obvious when 75 μg iron was injected. In the parenchymal veins, the relative mean (± SE) value of the susceptibility increased by 13.5 (± 1.0)% at 15 min post-tracer infusion (p < 0.01), and 33.6 (± 6.7)% at 45 min post-tracer infusion (p = 0.01), compared to baseline. In contrast to the parenchymal veins, a negligible amount of CSF tracer entered the parenchymal arteries: 1.3 (± 2.6)% at 15 min post-tracer infusion (p = 0.6), and 12 (± 19)% at 45 min post-tracer infusion (p = 0.5), compared to baseline. CONCLUSIONS: MRI tracers can enter the parenchymal vascular system and more MRI tracers were observed in the cerebral venous than arterial vessels, suggesting the direct participation of parenchymal vascular system in CWC. KEY POINTS: • MRI results revealed that the parenchymal venous system directly participates in cerebrospinal fluid tracer clearance following ICM infusion of MRI tracer. • Different sizes of MRI tracers can enter the parenchymal venous system.
OBJECTIVES: The current understanding of cerebral waste clearance (CWC) involves cerebrospinal fluid (CSF) participation but lacks convincing evidence for the direct participation of the parenchymal vascular system. The objective of this study was to evaluate the role of the parenchymal vascular system in CSF tracer clearance in rats. METHODS: We used superparamagnetic iron oxide-enhanced susceptibility-weighted imaging (SPIO-SWI) and quantitative susceptibility mapping (QSM) methods to simultaneously study 7 T MRI signal changes in parenchymal veins, arteries, and their corresponding para-vascular spaces in 26 rats, following intra-cisterna magna (ICM) infusion of different CSF tracers (FeREX, Ferumoxytol, Fe-Dextran) to determine the amount of tracer in the artery and vein quantitatively. RESULTS: We observed that the parenchymal venous system participated in CSF tracer clearance following ICM infusion of different MRI tracers with different concentrations of iron. Parenchymal venous participation was more obvious when 75 μg iron was injected. In the parenchymal veins, the relative mean (± SE) value of the susceptibility increased by 13.5 (± 1.0)% at 15 min post-tracer infusion (p < 0.01), and 33.6 (± 6.7)% at 45 min post-tracer infusion (p = 0.01), compared to baseline. In contrast to the parenchymal veins, a negligible amount of CSF tracer entered the parenchymal arteries: 1.3 (± 2.6)% at 15 min post-tracer infusion (p = 0.6), and 12 (± 19)% at 45 min post-tracer infusion (p = 0.5), compared to baseline. CONCLUSIONS: MRI tracers can enter the parenchymal vascular system and more MRI tracers were observed in the cerebral venous than arterial vessels, suggesting the direct participation of parenchymal vascular system in CWC. KEY POINTS: • MRI results revealed that the parenchymal venous system directly participates in cerebrospinal fluid tracer clearance following ICM infusion of MRI tracer. • Different sizes of MRI tracers can enter the parenchymal venous system.
Authors: Satish Krishnamurthy; Jie Li; Yimin Shen; Thomas M Duncan; Kenneth A Jenrow; E Mark Haacke Journal: Brain Res Date: 2017-10-21 Impact factor: 3.252
Authors: Jeffrey J Iliff; Minghuan Wang; Yonghong Liao; Benjamin A Plogg; Weiguo Peng; Georg A Gundersen; Helene Benveniste; G Edward Vates; Rashid Deane; Steven A Goldman; Erlend A Nagelhus; Maiken Nedergaard Journal: Sci Transl Med Date: 2012-08-15 Impact factor: 17.956
Authors: Michal Arbel-Ornath; Eloise Hudry; Katharina Eikermann-Haerter; Steven Hou; Julia L Gregory; Lingzhi Zhao; Rebecca A Betensky; Matthew P Frosch; Steven M Greenberg; Brian J Bacskai Journal: Acta Neuropathol Date: 2013-07-02 Impact factor: 17.088