In this lecture, different confounds that can affect resting state and task fMRI in the setting of focal brain lesions will be discussed, including most importantly neurovascular uncoupling and susceptibility effects.
OUTLINE FOR LECTURE:
Susceptibility artifacts
Detection of susceptibility artifacts and their effect on fMRI (task and rs-fMRI)
Metallic implants vs ultra-high field effects in cases of structural brain lesions
Neurovascular decoupling (a.k.a., neurovascular uncoupling, or NVU)---pathophysiology, imaging detection and impact on clinical fMRI
Definition and pathophysiology
Imaging detection of NVU and its impact on clinical fMRI/rs-fMRI in the setting of focal brain lesions
CVR vs task-fMRI vs functional field mapping for NVU detection
Specific impact on particular rsfMRI metrics
Seed-based correlation analysis (SCA)
Independent component analysis (ICA)
Frequency domain metrics (ALFF, fALFF)
Regional Homogeneity metrics (ReHo)
Graph theory applications to rs-fMRI
REFERENCES:
Pillai JJ, Zacà D. Comparison of BOLD cerebrovascular reactivity mapping and DSC MR perfusion imaging for prediction of neurovascular uncoupling potential in brain tumors. Technol Cancer Res Treat 2012;11(4):361-74.
Pillai JJ, Mikulis DJ. Cerebrovascular Reactivity Mapping: An Evolving Standard for Clinical Functional Imaging. AJNR Am J Neuroradiol 2015;36(1):7-13.
Zacà D, Jovicich J, Nadar SR, et al. Cerebrovascular reactivity mapping in patients with low grade gliomas undergoing presurgical sensorimotor mapping with BOLD fMRI. J Magn Reson Imaging 2014;40(2):383-90.
Agarwal S, Sair HI, Yahyavi-Firouz-Abadi N, et al. Neurovascular uncoupling in resting state fMRI demonstrated in patients with primary brain gliomas. J Magn Reson Imaging 2016;43(3):620-626
Agarwal S, Sair HI, Airan R, et al. Demonstration of Brain Tumor-Induced Neurovascular Uncoupling in Resting-State fMRI at Ultrahigh Field. Brain Connect 2016;6(4):267-72.
Agarwal S, Sair H, Pillai JJ. The resting state fMRI regional homogeneity (ReHo) metrics KCC-ReHo & Cohe-ReHo are valid indicators of tumor-related neurovascular uncoupling. In Proceedings of the 25rd Annual Meeting of ISMRM, Honolulu, Hawaii, USA, 2017. Abstract 5327.
Agarwal S, Lu H, Pillai JJ. Value of frequency domain resting state fMRI metrics ALFF & fALFF in the assessment of brain tumor induced neurovascular uncoupling. In Proceedings of the 25rd Annual Meeting of ISMRM, Honolulu, Hawaii, USA, 2017. Abstract 5326.
Park JE, Kim HS, Kim SJ, et al. Alteration of long-distance functional connectivity and network topology in patients with supratentorial gliomas. Neuroradiology 2016;58(3):311-20.
Agarwal S, Sair HI, Pillai JJ. Limitations of rsfMRI in the setting of focal brain lesions. IN Neuroimaging Clinics of North America Nov. 2017 issue, entitled, “Functional Connectivity,” Pillai JJ (Ed.). in press.