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Zinos A, Wagner JC, Beardsley SA, Chen WL, Conant L, Malloy M, Heffernan J, Quirk B, Prost R, Maheshwari M, Sugar J, Whelan HT. Spatial correspondence of cortical activity measured with whole head fNIRS and fMRI: Toward clinical use within subject. Neuroimage 2024; 290:120569. [PMID: 38461959 DOI: 10.1016/j.neuroimage.2024.120569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/15/2023] [Accepted: 03/07/2024] [Indexed: 03/12/2024] Open
Abstract
Functional near infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) both measure the hemodynamic response, and so both imaging modalities are expected to have a strong correspondence in regions of cortex adjacent to the scalp. To assess whether fNIRS can be used clinically in a manner similar to fMRI, 22 healthy adult participants underwent same-day fMRI and whole-head fNIRS testing while they performed separate motor (finger tapping) and visual (flashing checkerboard) tasks. Analyses were conducted within and across subjects for each imaging approach, and regions of significant task-related activity were compared on the cortical surface. The spatial correspondence between fNIRS and fMRI detection of task-related activity was good in terms of true positive rate, with fNIRS overlap of up to 68 % of the fMRI for analyses across subjects (group analysis) and an average overlap of up to 47.25 % for individual analyses within subject. At the group level, the positive predictive value of fNIRS was 51 % relative to fMRI. The positive predictive value for within subject analyses was lower (41.5 %), reflecting the presence of significant fNIRS activity in regions without significant fMRI activity. This could reflect task-correlated sources of physiologic noise and/or differences in the sensitivity of fNIRS and fMRI measures to changes in separate (vs. combined) measures of oxy and de-oxyhemoglobin. The results suggest whole-head fNIRS as a noninvasive imaging modality with promising clinical utility for the functional assessment of brain activity in superficial regions of cortex physically adjacent to the skull.
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Affiliation(s)
- Anthony Zinos
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Julie C Wagner
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Scott A Beardsley
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA; Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Wei-Liang Chen
- Center for Neuroscience Research, Children's National Medical Center, George Washington University, Washington DC, USA
| | - Lisa Conant
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Marsha Malloy
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Neurology, Children's Wisconsin, Milwaukee, WI, USA
| | - Joseph Heffernan
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brendan Quirk
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Robert Prost
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Mohit Maheshwari
- Department of Radiology, Children's Wisconsin, Milwaukee, WI, USA
| | - Jeffrey Sugar
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Harry T Whelan
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Neurology, Children's Wisconsin, Milwaukee, WI, USA
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Kokkinos V, Chatzisotiriou A, Seimenis I. Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging-Tractography in Resective Brain Surgery: Lesion Coverage Strategies and Patient Outcomes. Brain Sci 2023; 13:1574. [PMID: 38002534 PMCID: PMC10670090 DOI: 10.3390/brainsci13111574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/04/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
Diffusion tensor imaging (DTI)-tractography and functional magnetic resonance imaging (fMRI) have dynamically entered the presurgical evaluation context of brain surgery during the past decades, providing novel perspectives in surgical planning and lesion access approaches. However, their application in the presurgical setting requires significant time and effort and increased costs, thereby raising questions regarding efficiency and best use. In this work, we set out to evaluate DTI-tractography and combined fMRI/DTI-tractography during intra-operative neuronavigation in resective brain surgery using lesion-related preoperative neurological deficit (PND) outcomes as metrics. We retrospectively reviewed medical records of 252 consecutive patients admitted for brain surgery. Standard anatomical neuroimaging protocols were performed in 127 patients, 69 patients had additional DTI-tractography, and 56 had combined DTI-tractography/fMRI. fMRI procedures involved language, motor, somatic sensory, sensorimotor and visual mapping. DTI-tractography involved fiber tracking of the motor, sensory, language and visual pathways. At 1 month postoperatively, DTI-tractography patients were more likely to present either improvement or preservation of PNDs (p = 0.004 and p = 0.007, respectively). At 6 months, combined DTI-tractography/fMRI patients were more likely to experience complete PND resolution (p < 0.001). Low-grade lesion patients (N = 102) with combined DTI-tractography/fMRI were more likely to experience complete resolution of PNDs at 1 and 6 months (p = 0.001 and p < 0.001, respectively). High-grade lesion patients (N = 140) with combined DTI-tractography/fMRI were more likely to have PNDs resolved at 6 months (p = 0.005). Patients with motor symptoms (N = 80) were more likely to experience complete remission of PNDs at 6 months with DTI-tractography or combined DTI-tractography/fMRI (p = 0.008 and p = 0.004, respectively), without significant difference between the two imaging protocols (p = 1). Patients with sensory symptoms (N = 44) were more likely to experience complete PND remission at 6 months with combined DTI-tractography/fMRI (p = 0.004). The intraoperative neuroimaging modality did not have a significant effect in patients with preoperative seizures (N = 47). Lack of PND worsening was observed at 6 month follow-up in patients with combined DTI-tractography/fMRI. Our results strongly support the combined use of DTI-tractography and fMRI in patients undergoing resective brain surgery for improving their postoperative clinical profile.
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Affiliation(s)
- Vasileios Kokkinos
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02215, USA
| | | | - Ioannis Seimenis
- Department of Medicine, School of Health Sciences, Democritus University of Thrace, 387479 Alexandroupolis, Greece;
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3
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Molz B, Herbik A, Baseler HA, de Best P, Raz N, Gouws A, Ahmadi K, Lowndes R, McLean RJ, Gottlob I, Kohl S, Choritz L, Maguire J, Kanowski M, Käsmann-Kellner B, Wieland I, Banin E, Levin N, Morland AB, Hoffmann MB. Achromatopsia-Visual Cortex Stability and Plasticity in the Absence of Functional Cones. Invest Ophthalmol Vis Sci 2023; 64:23. [PMID: 37847226 PMCID: PMC10584018 DOI: 10.1167/iovs.64.13.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/07/2023] [Indexed: 10/18/2023] Open
Abstract
Purpose Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex is congenitally deprived of visual input, which prompts a fundamental question: is the cortical representation of the central visual field in patients with achromatopsia remapped to take up processing of paracentral inputs? Such remapping might interfere with gene therapeutic treatments aimed at restoring cone function. Methods We conducted a multicenter study to explore the nature and plasticity of vision in the absence of functional cones in a cohort of 17 individuals affected by autosomal recessive achromatopsia and confirmed biallelic disease-causing CNGA3 or CNGB3 mutations. Specifically, we tested the hypothesis of foveal remapping in human achromatopsia. For this purpose, we applied two independent functional magnetic resonance imaging (fMRI)-based mapping approaches, i.e. conventional phase-encoded eccentricity and population receptive field mapping, to separate data sets. Results Both fMRI approaches produced the same result in the group comparison of achromatopsia versus healthy controls: sizable remapping of the representation of the central visual field in the primary visual cortex was not apparent. Conclusions Remapping of the cortical representation of the central visual field is not a general feature in achromatopsia. It is concluded that plasticity of the human primary visual cortex is less pronounced than previously assumed. A pretherapeutic imaging workup is proposed to optimize interventions.
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Affiliation(s)
- Barbara Molz
- Department of Psychology, University of York, Heslington, York, United Kingdom
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
- Language & Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
| | - Anne Herbik
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Heidi A. Baseler
- Department of Psychology, University of York, Heslington, York, United Kingdom
- Hull York Medical School, University of York, Heslington, York, United Kingdom
- York Biomedical Research Institute, University of York, Heslington, York, United Kingdom
| | - Peter de Best
- fMRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Noa Raz
- fMRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Andre Gouws
- Department of Psychology, University of York, Heslington, York, United Kingdom
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Khazar Ahmadi
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Rebecca Lowndes
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Rebecca J. McLean
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, Tübingen, Germany
| | - Lars Choritz
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - John Maguire
- School of Optometry and Vision Sciences, University of Bradford, Bradford, United Kingdom
- Department of Neurophysiology, Children's Health Ireland (CHI) at Crumlin, Dublin, Ireland
| | - Martin Kanowski
- Department of Neurology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Barbara Käsmann-Kellner
- Department of Ophthalmology, Saarland University Hospital and Medical Faculty of the Saarland University Hospital, Homburg, Germany
| | - Ilse Wieland
- Department for Molecular Genetics, Institute for Human Genetics, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Eyal Banin
- Center for Retinal and Macular Degenerations, Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Netta Levin
- fMRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Antony B. Morland
- Department of Psychology, University of York, Heslington, York, United Kingdom
- York Biomedical Research Institute, University of York, Heslington, York, United Kingdom
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Michael B. Hoffmann
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
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4
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Agarwal S, Welker KM, Black DF, Little JT, DeLone DR, Messina SA, Passe TJ, Bettegowda C, Pillai JJ. Detection and Mitigation of Neurovascular Uncoupling in Brain Gliomas. Cancers (Basel) 2023; 15:4473. [PMID: 37760443 PMCID: PMC10527022 DOI: 10.3390/cancers15184473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/28/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) with blood oxygen level-dependent (BOLD) technique is useful for preoperative mapping of brain functional networks in tumor patients, providing reliable in vivo detection of eloquent cortex to help reduce the risk of postsurgical morbidity. BOLD task-based fMRI (tb-fMRI) is the most often used noninvasive method that can reliably map cortical networks, including those associated with sensorimotor, language, and visual functions. BOLD resting-state fMRI (rs-fMRI) is emerging as a promising ancillary tool for visualization of diverse functional networks. Although fMRI is a powerful tool that can be used as an adjunct for brain tumor surgery planning, it has some constraints that should be taken into consideration for proper clinical interpretation. BOLD fMRI interpretation may be limited by neurovascular uncoupling (NVU) induced by brain tumors. Cerebrovascular reactivity (CVR) mapping obtained using breath-hold methods is an effective method for evaluating NVU potential.
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Affiliation(s)
- Shruti Agarwal
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
| | - Kirk M. Welker
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
| | - David F. Black
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
| | - Jason T. Little
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
| | - David R. DeLone
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
| | - Steven A. Messina
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
| | - Theodore J. Passe
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
| | - Chetan Bettegowda
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
| | - Jay J. Pillai
- Division of Neuroradiology, Department of Radiology, Mayo Clinic Rochester & Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA; (K.M.W.); (D.F.B.); (J.T.L.); (D.R.D.); (S.A.M.); (T.J.P.)
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA;
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5
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Vachha BA, Middlebrooks EH. Brain Functional Imaging Anatomy. Neuroimaging Clin N Am 2022; 32:491-505. [PMID: 35843658 DOI: 10.1016/j.nic.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Human brain function is an increasingly complex framework that has important implications in clinical medicine. In this review, the anatomy of the most commonly assessed brain functions in clinical neuroradiology, including motor, language, and vision, is discussed. The anatomy and function of the primary and secondary sensorimotor areas are discussed with clinical case examples. Next, the dual stream of language processing is reviewed, as well as its implications in clinical medicine and surgical planning. Last, the authors discuss the striate and extrastriate visual cortex and review the dual stream model of visual processing.
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Affiliation(s)
- Behroze Adi Vachha
- Department of Radiology, Neuroradiology Section, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Brain Tumor Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
| | - Erik H Middlebrooks
- Department of Radiology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA; Department of Neurosurgery, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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6
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Prabhakaran GT, Al-Nosairy KO, Tempelmann C, Thieme H, Hoffmann MB. Mapping Visual Field Defects With fMRI - Impact of Approach and Experimental Conditions. Front Neurosci 2021; 15:745886. [PMID: 34566575 PMCID: PMC8455880 DOI: 10.3389/fnins.2021.745886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/19/2021] [Indexed: 11/13/2022] Open
Abstract
Current initiatives to restore vision emphasize the need for objective assessments of visual field (VF) defects as pursued with functional magnetic resonance imaging (fMRI) approaches. Here, we compared population receptive field (pRF) mapping-based VF reconstructions to an fMRI method that uses more robust visual stimulation (on-off block design) in combination with individualized anatomy-driven retinotopic atlas-information (atlas-based VF). We investigated participants with sizable peripheral VF-deficits due to advanced glaucoma (n = 4) or retinitis pigmentosa (RP; n = 2) and controls (n = 6) with simulated scotoma. We obtained (1) standard automated perimetry (SAP) data as reference VFs and 3T fMRI data for (2) pRF-mapping [8-direction bar stimulus, fixation color change task] and (3) block-design full-field stimulation [8-direction drifting contrast patterns during (a) passive viewing (PV) and (b) one-back-task (OBT; reporting successions of identical motion directions) to probe the impact of previously reported task-related unspecific visual cortex activations]. Correspondence measures between the SAP and fMRI-based VFs were accuracy, assisted by sensitivity and specificity. We found an accuracy of pRF-based VF from V1 in patients [median: 0.62] that was similar to previous reports and increased by adding V2 and V3 to the analysis [0.74]. In comparison to the pRF-based VF, equivalent accuracies were obtained for the atlas-based VF for both PV [0.67] and, unexpectedly, the OBT [0.59], where, however, unspecific cortical activations were reflected by a reduction in sensitivity [0.71 (PV) and 0.35 (OBT)]. In conclusion, in patients with peripheral VF-defects, we demonstrate that previous fMRI procedures to obtain VF-estimates might be enhanced by: (1) pooling V1-V3 to enhance accuracy; (2) reporting sensitivity and specificity measures to increase transparency of the VF-reconstruction metric; (3) applying atlas-based procedures, if pRF-based VFs are not available or difficult to obtain; and (4) giving, counter-intuitively, preference to PV. These findings are expected to provide guidance to overcome current limitations of translating fMRI-based methods to a clinical work-up.
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Affiliation(s)
| | | | - Claus Tempelmann
- Department of Neurology, Otto von Guericke University, Magdeburg, Germany
| | - Hagen Thieme
- Department of Ophthalmology, Otto von Guericke University, Magdeburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto von Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
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7
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Fesharaki NJ, Mathew AB, Mathis JR, Huddleston WE, Reuss JL, Pillai JJ, DeYoe EA. Effects of Thresholding on Voxel-Wise Correspondence of Breath-Hold and Resting-State Maps of Cerebrovascular Reactivity. Front Neurosci 2021; 15:654957. [PMID: 34504411 PMCID: PMC8421787 DOI: 10.3389/fnins.2021.654957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Functional magnetic resonance imaging for presurgical brain mapping enables neurosurgeons to identify viable tissue near a site of operable pathology which might be at risk of surgery-induced damage. However, focal brain pathology (e.g., tumors) may selectively disrupt neurovascular coupling while leaving the underlying neurons functionally intact. Such neurovascular uncoupling can result in false negatives on brain activation maps thereby compromising their use for surgical planning. One way to detect potential neurovascular uncoupling is to map cerebrovascular reactivity using either an active breath-hold challenge or a passive resting-state scan. The equivalence of these two methods has yet to be fully established, especially at a voxel level of resolution. To quantitatively compare breath-hold and resting-state maps of cerebrovascular reactivity, we first identified threshold settings that optimized coverage of gray matter while minimizing false responses in white matter. When so optimized, the resting-state metric had moderately better gray matter coverage and specificity. We then assessed the spatial correspondence between the two metrics within cortical gray matter, again, across a wide range of thresholds. Optimal spatial correspondence was strongly dependent on threshold settings which if improperly set tended to produce statistically biased maps. When optimized, the two CVR maps did have moderately good correspondence with each other (mean accuracy of 73.6%). Our results show that while the breath-hold and resting-state maps may appear qualitatively similar they are not quantitatively identical at a voxel level of resolution.
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Affiliation(s)
- Nooshin J Fesharaki
- College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States.,Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Amy B Mathew
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jedidiah R Mathis
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wendy E Huddleston
- College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - James L Reuss
- Prism Clinical Imaging, Inc., Milwaukee, WI, United States
| | - Jay J Pillai
- Neuroradiology Division, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Edgar A DeYoe
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
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8
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A low-cost telescope for enhanced stimulus visual field coverage in functional MRI. J Neurosci Methods 2020; 350:109023. [PMID: 33316315 DOI: 10.1016/j.jneumeth.2020.109023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/29/2020] [Accepted: 12/03/2020] [Indexed: 11/23/2022]
Abstract
BACKGROUND A common limitation of typical projection systems used for visual fMRI is the limited field of view that can be presented to the observer within the scanner. A wide field of view over which stimuli can be presented is critical when investigating peripheral visual function, in particular visual disorders or diseases that lead to the loss of peripheral vision. NEW METHOD We present a relatively low-cost Galilean telescopic device that can be used in most MRI scanners to double the effective visual field being presented. The system described is non-ferromagnetic, and compatible with most standard methods of visual presentation in MRI environments. The increase in area of visual cortex activation was quantified by comparing the extent of visual activity evoked by observing flickering checkerboards with and without the telescope in place. RESULTS In all three observers that reported image fusion from the telescope, the extent of cortical activation was greater with the telescope, while in the fourth observer there was no difference between the two methods due to a lack of fusion. CONCLUSION The telescope is a low cost, easy to implement solution in situations where changes to the existing equipment or setup are not feasible.
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9
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Abstract
Neurovascular uncoupling (NVU) is one of the most important confounds of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMR imaging) in the setting of focal brain lesions such as brain tumors. This article reviews the assessment of NVU related to focal brain lesions with emphasis on the use of cerebrovascular reactivity mapping measurement methods and resting state BOLD fMR imaging metrics in the detection of NVU, as well as the use of amplitude of low-frequency fluctuation metrics to mitigate the effects of NVU on clinical fMR imaging activation.
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Affiliation(s)
- Shruti Agarwal
- Division of Neuroradiology, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
| | - Haris I Sair
- Division of Neuroradiology, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA; The Malone Center for Engineering in Healthcare, The Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jay J Pillai
- Division of Neuroradiology, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA; Department of Neurosurgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287, USA.
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10
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Silva MA, See AP, Essayed WI, Golby AJ, Tie Y. Challenges and techniques for presurgical brain mapping with functional MRI. NEUROIMAGE-CLINICAL 2017; 17:794-803. [PMID: 29270359 PMCID: PMC5735325 DOI: 10.1016/j.nicl.2017.12.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/10/2017] [Accepted: 12/05/2017] [Indexed: 01/22/2023]
Abstract
Functional magnetic resonance imaging (fMRI) is increasingly used for preoperative counseling and planning, and intraoperative guidance for tumor resection in the eloquent cortex. Although there have been improvements in image resolution and artifact correction, there are still limitations of this modality. In this review, we discuss clinical fMRI's applications, limitations and potential solutions. These limitations depend on the following parameters: foundations of fMRI, physiologic effects of the disease, distinctions between clinical and research fMRI, and the design of the fMRI study. We also compare fMRI to other brain mapping modalities which should be considered as alternatives or adjuncts when appropriate, and discuss intraoperative use and validation of fMRI. These concepts direct the clinical application of fMRI in neurosurgical patients. fMRI is increasingly used for presurgical brain mapping for surgical planning. Understanding of the limitations of fMRI is critical for its clinical use. Clinical fMRI's challenges and potential solutions are discussed. Intraoperative use and validation of fMRI are discussed.
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Affiliation(s)
- Michael A Silva
- Harvard Medical School, Boston, MA, USA; Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA, USA
| | - Alfred P See
- Harvard Medical School, Boston, MA, USA; Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA, USA
| | - Walid I Essayed
- Harvard Medical School, Boston, MA, USA; Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA, USA
| | - Alexandra J Golby
- Harvard Medical School, Boston, MA, USA; Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA, USA; Department of Radiology, Brigham and Women's Hospital, Boston, MA, USA
| | - Yanmei Tie
- Harvard Medical School, Boston, MA, USA; Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA, USA.
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