Ararat Chakhoyan

Assistant Professor of Research Physiology & Neuroscience

Assistant Director, MRI/PET Research Unit

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Overview

Dr. Chakhoyan is the Assistant Professor of Research in the department of Physiology and Neuroscience at the Zilkha Neurogenetic Institute in the Keck School of Medicine at USC. He is involved in different ongoing research projects in the Zlokovic lab. His day-to-day activity includes research design, implementation of innovative methods for human and mouse brain MRI/PET image acquisition, post-processing, analyze and result interpretation. His current research direction and scope of work in Project 1 within the Program Project “Vascular Contribution to Dementia and Genetic Risk Factors for Alzheimer’s Disease (NIH/NIA:1P01AG052350-05)” and the associated sister grant “Vascular Contribution to Dementia and Amyloid and Tau Lesions in APOE4 Carriers (Alzheimer’s Association 008369-00001) led by Drs Zlokovic and Toga is to measure the poorly understood interplay between blood-brain barrier permeability (quantified by MRI), amyloid and tau accumulation (quantified by PET), vascular (small vessel disease, hypertension, diabetes, smoking) and genetic risk factors (Apolipoprotein E4) that is a major risk factor for Alzheimer’s disease. A key technical challenge is the implementation of early MRI/PET biomarkers that can predict disease progression, which helps us to identify potential targets for intervention and improve risk prediction.

Publications

  • Magnetic resonance imaging of white matter response to diesel exhaust particles Res Sq. 2023 Jul 18. . View in PubMed
  • Magnetic resonance imaging of hypoxia in acute stroke compared with fluorine-18 fluoromisonidazole-positron emission tomography: A cross-validation study? NMR Biomed. 2023 03; 36(3):e4858.. View in PubMed
  • Editorial for “MRI-Based Investigation of Association Between Cerebrovascular Structural Alteration and White Matter Hyperintensity Induced by High Blood Pressure” J Magn Reson Imaging. 2021 11; 54(5):1527-1528. . View in PubMed
  • Simultaneous Mapping of Vasculature, Hypoxia, and Proliferation Using Dynamic Susceptibility Contrast MRI, 18F-FMISO PET, and 18F-FLT PET in Relation to Contrast Enhancement in Newly Diagnosed Glioblastoma J Nucl Med. 2021 10; 62(10):1349-1356. . View in PubMed
  • APOE4 leads to blood-brain barrier dysfunction predicting cognitive decline Nature. 2020 05; 581(7806):71-76. . View in PubMed
  • Multiparametric MR-PET Imaging Predicts Pharmacokinetics and Clinical Response to GDC-0084 in Patients with Recurrent High-Grade Glioma Clin Cancer Res. 2020 07 01; 26(13):3135-3144. . View in PubMed
  • pH-weighted amine chemical exchange saturation transfer echoplanar imaging (CEST-EPI) as a potential early biomarker for bevacizumab failure in recurrent glioblastoma J Neurooncol. 2019 May; 142(3):587-595. . View in PubMed
  • Probabilistic independent component analysis of dynamic susceptibility contrast perfusion MRI in metastatic brain tumors Cancer Imaging. 2019 Mar 18; 19(1):14. . View in PubMed
  • Association between Tumor Acidity and Hypervascularity in Human Gliomas Using pH-Weighted Amine Chemical Exchange Saturation Transfer Echo-Planar Imaging and Dynamic Susceptibility Contrast Perfusion MRI at 3T AJNR Am J Neuroradiol. 2019 06; 40(6):979-986. . View in PubMed
  • Validation of vessel size imaging (VSI) in high-grade human gliomas using magnetic resonance imaging, image-guided biopsies, and quantitative immunohistochemistry Sci Rep. 2019 02 26; 9(1):2846. . View in PubMed
  • pH-weighted molecular MRI in human traumatic brain injury (TBI) using amine proton chemical exchange saturation transfer echoplanar imaging (CEST EPI) Neuroimage Clin. 2019; 22:101736. . View in PubMed
  • Metabolic characterization of human IDH mutant and wild type gliomas using simultaneous pH- and oxygen-sensitive molecular MRI Neuro Oncol. 2019 09 06; 21(9):1184-1196. . View in PubMed
  • 18F-FDOPA PET and MRI characteristics correlate with degree of malignancy and predict survival in treatment-naïve gliomas: a cross-sectional study J Neurooncol. 2018 Sep; 139(2):399-409. . View in PubMed
  • Mono-exponential, diffusion kurtosis and stretched exponential diffusion MR imaging response to chemoradiation in newly diagnosed glioblastoma J Neurooncol. 2018 Sep; 139(3):651-659. . View in PubMed
  • Simultaneous pH-sensitive and oxygen-sensitive MRI of human gliomas at 3 T using multi-echo amine proton chemical exchange saturation transfer spin-and-gradient echo echo-planar imaging (CEST-SAGE-EPI) Magn Reson Med. 2018 11; 80(5):1962-1978. . View in PubMed
  • Improved Spatiotemporal Resolution of Dynamic Susceptibility Contrast Perfusion MRI in Brain Tumors Using Simultaneous Multi-Slice Echo-Planar Imaging AJNR Am J Neuroradiol. 2018 01; 39(1):43-45. . View in PubMed
  • Post-chemoradiation volumetric response predicts survival in newly diagnosed glioblastoma treated with radiation, temozolomide, and bevacizumab or placebo Neuro Oncol. 2018 10 09; 20(11):1525-1535. . View in PubMed
  • Volumetric response quantified using T1 subtraction predicts long-term survival benefit from cabozantinib monotherapy in recurrent glioblastoma Neuro Oncol. 2018 09 03; 20(10):1411-1418. . View in PubMed
  • Diffusion MRI Phenotypes Predict Overall Survival Benefit from Anti-VEGF Monotherapy in Recurrent Glioblastoma: Converging Evidence from Phase II Trials Clin Cancer Res. 2017 Oct 01; 23(19):5745-5756. . View in PubMed
  • Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain J Cereb Blood Flow Metab. 2017 Jul; 37(7):2584-2597. . View in PubMed
  • Carbogen-induced increases in tumor oxygenation depend on the vascular status of the tumor: A multiparametric MRI study in two rat glioblastoma models J Cereb Blood Flow Metab. 2017 Jun; 37(6):2270-2282. . View in PubMed
  • FMISO-PET-derived brain oxygen tension maps: application to glioblastoma and less aggressive gliomas Sci Rep. 2017 08 31; 7(1):10210. . View in PubMed
  • Imaging Modalities to Assess Oxygen Status in Glioblastoma Front Med (Lausanne). 2015; 2:57. . View in PubMed