Suppression of Vascular Artifacts in Functional Magnetic Resonance Images Using MR Angiograms

This paper describes a method for processing functional magnetic resonance images that suppresses signal changes originating from macroscopic veins visible in acquired magnetic resonance angiograms. Finger tapping experiments were performed on a 1.5-T scanner and the response was evaluated with voxel-by-voxel cross-correlation of the time course with a sinusoid at the paradigm frequency. After applying a vascular mask to suppress signal changes under macroscopic vessels, the vascular and nonvascular subpopulations of the data were compared. By visual inspection, the method was found to remove extracortical activation while preserving activation in the parenchyma. The observed higher signal amplitudes and temporal phase lags of the vascular population agree with theoretical models and previous studies. A significant portion of negatively correlated voxels occurs adjacent to through-plane vessels. Finally, comparing the centers of mass of the activated area before and after vascular suppression showed significant shifts in some subjects.

[1]  J. Cohen,et al.  Spiral K‐space MR imaging of cortical activation , 1995, Journal of magnetic resonance imaging : JMRI.

[2]  D. Weinberger,et al.  Functional Mapping of Human Sensorimotor Cortex with 3D BOLD fMRI Correlates Highly with H215O PET rCBF , 1996, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[3]  H. Yonas,et al.  Use of acetazolamide-challenge xenon CT in the assessment of cerebral blood flow dynamics in patients with arteriovenous malformations. , 1990, AJNR. American journal of neuroradiology.

[4]  Jean A. Tkach,et al.  2D and 3D high resolution gradient echo functional imaging of the brain: Venous contributions to signal in motor cortex studies , 1994, NMR in biomedicine.

[5]  J. R. Baker,et al.  The intravascular contribution to fmri signal change: monte carlo modeling and diffusion‐weighted studies in vivo , 1995, Magnetic resonance in medicine.

[6]  Jonathan D. Cohen,et al.  Improved Assessment of Significant Activation in Functional Magnetic Resonance Imaging (fMRI): Use of a Cluster‐Size Threshold , 1995, Magnetic resonance in medicine.

[7]  R. S. Hinks,et al.  Spin‐echo and gradient‐echo epi of human brain activation using bold contrast: A comparative study at 1.5 T , 1994, NMR in biomedicine.

[8]  D. Weinberger,et al.  Three-dimensional functional magnetic resonance imaging of human brain on a clinical 1.5-T scanner. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[9]  J P Donoghue,et al.  Motor Areas of the Cerebral Cortex , 1994, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[10]  Adrian T. Lee,et al.  Discrimination of Large Venous Vessels in Time‐Course Spiral Blood‐Oxygen‐Level‐Dependent Magnetic‐Resonance Functional Neuroimaging , 1995, Magnetic resonance in medicine.

[11]  H. Alkadhi,et al.  Localization of the motor hand area to a knob on the precentral gyrus. A new landmark. , 1997, Brain : a journal of neurology.

[12]  G H Glover,et al.  Decomposition of inflow and blood oxygen level‐dependent (BOLD) effects with dual‐echo spiral gradient‐recalled echo (GRE) fMRI , 1996, Magnetic resonance in medicine.

[13]  J. Binder,et al.  Functional magnetic resonance imaging of complex human movements , 1993, Neurology.

[14]  D. Tank,et al.  4 Tesla gradient recalled echo characteristics of photic stimulation‐induced signal changes in the human primary visual cortex , 1993 .

[15]  J H Duyn,et al.  Inflow versus deoxyhemoglobin effects in bold functional MRI using gradient echoes at 1.5 T , 1994, NMR in biomedicine.

[16]  A. Kleinschmidt,et al.  Brain or veinoxygenation or flow? On signal physiology in functional MRI of human brain activation , 1994, NMR in biomedicine.

[17]  E C Wong,et al.  Processing strategies for time‐course data sets in functional mri of the human brain , 1993, Magnetic resonance in medicine.

[18]  J. Pauly,et al.  A homogeneity correction method for magnetic resonance imaging with time-varying gradients. , 1991, IEEE transactions on medical imaging.

[19]  H. Duvernoy,et al.  Cortical blood vessels of the human brain , 1981, Brain Research Bulletin.

[20]  M Requardt,et al.  Functional cooperativity of human cortical motor areas during self-paced simple finger movements. A high-resolution MRI study. , 1994, Brain : a journal of neurology.

[21]  E. Haacke,et al.  Identification of vascular structures as a major source of signal contrast in high resolution 2D and 3D functional activation imaging of the motor cortex at l.5T preliminary results , 1993, Magnetic resonance in medicine.

[22]  A L Benabid,et al.  Functional MRI of the human brain: predominance of signals from extracerebral veins. , 1994, Neuroreport.

[23]  B. Biswal,et al.  Negative pixels in functional maps of sensorimotor tasks , 1996, NeuroImage.

[24]  Ravi S. Menon,et al.  Functional brain mapping by blood oxygenation level-dependent contrast magnetic resonance imaging. A comparison of signal characteristics with a biophysical model. , 1993, Biophysical journal.

[25]  J. Mazziotta,et al.  MRI‐PET Registration with Automated Algorithm , 1993, Journal of computer assisted tomography.

[26]  J. Haxby,et al.  A difference in fMRI time courses between areas of increased and decreased neural activity , 1996, NeuroImage.