Michelle Miller-Thomas - Academia.edu (original) (raw)
Papers by Michelle Miller-Thomas
PloS one, 2018
Functional magnetic resonance imaging (fMRI) is an important tool for pre-surgical evaluation of ... more Functional magnetic resonance imaging (fMRI) is an important tool for pre-surgical evaluation of eloquent cortex. Classic task-based paradigms require patient participation and individual imaging sequence acquisitions for each functional domain that is being assessed. Resting state fMRI (rs-fMRI), however, enables functional localization without patient participation and can evaluate numerous functional domains with a single imaging session. To date, post-processing of this resting state data has been resource intensive, which limits its widespread application for routine clinical use. Through a novel automated algorithm and advanced imaging IT structure, we report the clinical application and the large-scale integration of rs-fMRI into routine neurosurgical practice. One hundred and ninety one consecutive patients underwent a 3T rs-fMRI, 83 of whom also underwent both motor and language task-based fMRI. Data were processed using a novel, automated, multi-layer perceptron algorithm ...
American Journal of Neuroradiology, 2009
The Journal of Nuclear Medicine, 2012
American Journal of Roentgenology
OBJECTIVE. The purpose of this article is to summarize the role of molecular imaging of the brain... more OBJECTIVE. The purpose of this article is to summarize the role of molecular imaging of the brain by use of SPECT, FDG PET, and non-FDG PET radiotracers in epilepsy. CONCLUSION. Quantitative image analysis with PET and SPECT has increased the diagnostic utility of these modalities in localizing epileptogenic onset zones. A multi-modal platform approach integrating the functional imaging of PET and SPECT with the morphologic information from MRI in presurgical evaluation of epilepsy can greatly improve outcomes.
PLOS ONE
Background Use of functional MRI (fMRI) in pre-surgical planning is a non-invasive method for pre... more Background Use of functional MRI (fMRI) in pre-surgical planning is a non-invasive method for pre-operative functional mapping for patients with brain tumors, especially tumors located near eloquent cortex. Currently, this practice predominantly involves task-based fMRI (T-fMRI). Resting state fMRI (RS-fMRI) offers an alternative with several methodological advantages. Here, we compare group-level analyses of RS-fMRI vs. T-fMRI as methods for language localization. Purpose To contrast RS-fMRI vs. T-fMRI as techniques for localization of language function. Methods We analyzed data obtained in 35 patients who had both T-fMRI and RS-fMRI scans during the course of pre-surgical evaluation. The RS-fMRI data were analyzed using a previously trained resting-state network classifier. The T-fMRI data were analyzed using conventional techniques. Group-level results obtained by both methods were evaluated in terms of two outcome measures: (1) inter-subject variability of response magnitude and (2) sensitivity/ specificity analysis of response topography, taking as ground truth previously reported maps of the language system based on intraoperative cortical mapping as well as meta-analytic maps of language task fMRI responses. Results Both fMRI methods localized major components of the language system (areas of Broca and Wernicke) although not with equal inter-subject consistency. Word-stem completion T-fMRI strongly activated Broca's area but also several task-general areas not specific to language. RS-fMRI provided a more specific representation of the language system.
Neuro-Oncology Practice
Background MRI alone has limited accuracy for delineating tumor margins and poorly predicts the a... more Background MRI alone has limited accuracy for delineating tumor margins and poorly predicts the aggressiveness of gliomas, especially when tumors do not enhance. This study evaluated simultaneous 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (FDOPA)-PET/MRI to define tumor volumes compared to MRI alone more accurately, assessed its role in patient management, and correlated PET findings with histopathology. Methods Ten patients with known or suspected gliomas underwent standard of care surgical resection and/or stereotactic biopsy. FDOPA-PET/MRI was performed prior to surgery, allowing for precise co-registration of PET, MR, and biopsies. The biopsy sites were modeled as 5-mm spheres, and the local FDOPA uptake at each site was determined. Correlations were performed between measures of tumor histopathology, and static and dynamic PET values: standardized uptake values (SUVs), tumor to brain ratios, metabolic tumor volumes, and tracer kinetics at volumes of interest (VOIs) and biopsy ...
Current Problems in Diagnostic Radiology
PLOS ONE
Objectives Primary brain tumors are composed of tumor cells, neural/glial tissues, edema, and vas... more Objectives Primary brain tumors are composed of tumor cells, neural/glial tissues, edema, and vasculature tissue. Conventional MRI has a limited ability to evaluate heterogeneous tumor pathologies. We developed a novel diffusion MRI-based method-Heterogeneity Diffusion Imaging (HDI)-to simultaneously detect and characterize multiple tumor pathologies and capillary blood perfusion using a single diffusion MRI scan. Methods Seven adult patients with primary brain tumors underwent standard-of-care MRI protocols and HDI protocol before planned surgical resection and/or stereotactic biopsy. Twelve tumor sampling sites were identified using a neuronavigational system and recorded for imaging data quantification. Metrics from both protocols were compared between World Health Organization (WHO) II and III tumor groups. Cerebral blood volume (CBV) derived from dynamic susceptibility contrast (DSC) perfusion imaging was also compared with the HDI-derived perfusion fraction. Results The conventional apparent diffusion coefficient did not identify differences between WHO II and III tumor groups. HDI-derived slow hindered diffusion fraction was significantly elevated in the WHO III group as compared with the WHO II group. There was a non-significantly PLOS ONE |
Glioma Imaging
Current strategies for treatment and management of gliomas incorporate molecular markers to indiv... more Current strategies for treatment and management of gliomas incorporate molecular markers to individualize patient care. Physiologic imaging identifies treatment-associated alterations in tissue properties including cellular viability, vascular function, and molecular response. Imaging biomarkers provide a noninvasive approach for early treatment response assessment and are an important tool to individualize patient management. Gliomas are heterogeneous tumors. Parametric response mapping (PRM) is a novel voxel-wise imaging analysis method which directly addresses the issue of tumor heterogeneity. PRM image analysis improves the predictive accuracy of imaging biomarkers in clinical applications including treatment response assessment. A multi-parametric imaging biomarker derived from MR perfusion and diffusion-weighted imaging (DWI) using a PRM analysis method provides early identification of high-grade glioma chemoradiation resistance. Further validation of PRM-derived imaging biomarkers is required prior to routine clinical application as an early treatment response marker.
Blood
Background: By combining the metabolic information of PET with the high soft tissue contrast of M... more Background: By combining the metabolic information of PET with the high soft tissue contrast of MRI, PET/MRI, most often performed with the glucose analogue [18F]fluorodeoxyglucose (FDG), has emerged as a powerful hybrid imaging modality for various oncologic conditions. Multiple myeloma (MM) is an attractive target for FDG-PET/MRI, as both MRI and FDG-PET/CT, when performed separately, have important limitations. For example, diffuse tracer uptake by normal marrow can obscure focal myeloma lesions on FDG-PET, especially in patients receiving marrow-stimulating agents (Hanrahan et al.,RadioGraphics, 2010), while the correlative CT images are less sensitive than MRI for subtle marrow infiltration (Baur-Melnyk et al., AJR, 2008). However, such abnormal marrow signal on MRI can persist despite clinical evidence of disease remission, while the resolution of FDG uptake by focal myeloma lesions closely correlates with clinical metrics of treatment response (Walker et al., Blood, 2004). Th...
Clinical Neurology and Neurosurgery
Neuroimaging Clinics of North America
Clinical Neurology and Neurosurgery
Computed tomographic angiography (CTA) is increasingly utilized to evaluate for traumatic cerebro... more Computed tomographic angiography (CTA) is increasingly utilized to evaluate for traumatic cerebrovascular injury (TCVI). The purpose of this study was to determine the yield, management effect, and risk of stroke or poor outcome of a positive CTA in a large cohort of trauma patients. A retrospective analysis was performed on 1290 consecutive trauma patients that underwent head and/or neck CTA at our level I trauma center from 2006 to 2015. Clinical variables assessed include mechanism of injury, neurological status, CTA findings, subsequent imaging results, patient management, and clinical outcomes. Among 1290 patients who underwent CTA, 200 (15.5%) were positive for TCVI, higher in blunt than penetrating trauma patients. In a generalized linear model, factors that increased likelihood of positive CTA included multiple cervical fractures, fractures with foraminal involvement, gunshot injury, Glasgow Coma Scale ≤ 13, and focal neurological deficit. Excluding cases with these factors lowered the positive rate to 4.3%. Of the 200 CTA-positives, 99 were treated for TCVI and 9 (4.5%) developed a subsequent stroke as compared to 5 (0.5%) in CTA-negative patients (odds ratio 10.2, Fisher exact test, p < 0.001). Risk of death or nursing facility discharge location was also higher in CTA-positive patients, correcting for age and presenting GCS (p < 0.01). CTA had a modest yield in identifying TCVI in this cohort. When positive, CTA influenced management and predicted an increased risk of subsequent stroke and poor outcome.
Neuroimaging clinics of North America, 2017
This article compares resting-state functional magnetic resonance (fMR) imaging with task fMR ima... more This article compares resting-state functional magnetic resonance (fMR) imaging with task fMR imaging for presurgical functional mapping of the sensorimotor (SM) region. Before tumor resection, 38 patients were scanned using both methods. The SM area was anatomically defined using 2 different software tools. Overlap of anatomic regions of interest with task activation maps and resting-state networks was measured in the SM region. A paired t-test showed higher overlap between resting-state maps and anatomic references compared with task activation when using a maximal overlap criterion. Resting state-derived maps are more comprehensive than those derived from task fMR imaging.
Magnetic Resonance Imaging Clinics of North America
PET/MR imaging benefits neurologic clinical care and research by providing spatially and temporal... more PET/MR imaging benefits neurologic clinical care and research by providing spatially and temporally matched anatomic MR imaging, advanced MR physiologic imaging, and metabolic PET imaging. MR imaging sequences and PET tracers can be modified to target physiology specific to a neurologic disease process, with applications in neurooncology, epilepsy, dementia, cerebrovascular disease, and psychiatric and neurologic research. Simultaneous PET/MR imaging provides efficient acquisition of multiple temporally matched datasets, and opportunities for motion correction and improved anatomic assignment of PET data. Current challenges include optimizing MR imaging-based attenuation correction and necessity for dual expertise in PET and MR imaging.
PloS one, 2018
Functional magnetic resonance imaging (fMRI) is an important tool for pre-surgical evaluation of ... more Functional magnetic resonance imaging (fMRI) is an important tool for pre-surgical evaluation of eloquent cortex. Classic task-based paradigms require patient participation and individual imaging sequence acquisitions for each functional domain that is being assessed. Resting state fMRI (rs-fMRI), however, enables functional localization without patient participation and can evaluate numerous functional domains with a single imaging session. To date, post-processing of this resting state data has been resource intensive, which limits its widespread application for routine clinical use. Through a novel automated algorithm and advanced imaging IT structure, we report the clinical application and the large-scale integration of rs-fMRI into routine neurosurgical practice. One hundred and ninety one consecutive patients underwent a 3T rs-fMRI, 83 of whom also underwent both motor and language task-based fMRI. Data were processed using a novel, automated, multi-layer perceptron algorithm ...
American Journal of Neuroradiology, 2009
The Journal of Nuclear Medicine, 2012
American Journal of Roentgenology
OBJECTIVE. The purpose of this article is to summarize the role of molecular imaging of the brain... more OBJECTIVE. The purpose of this article is to summarize the role of molecular imaging of the brain by use of SPECT, FDG PET, and non-FDG PET radiotracers in epilepsy. CONCLUSION. Quantitative image analysis with PET and SPECT has increased the diagnostic utility of these modalities in localizing epileptogenic onset zones. A multi-modal platform approach integrating the functional imaging of PET and SPECT with the morphologic information from MRI in presurgical evaluation of epilepsy can greatly improve outcomes.
PLOS ONE
Background Use of functional MRI (fMRI) in pre-surgical planning is a non-invasive method for pre... more Background Use of functional MRI (fMRI) in pre-surgical planning is a non-invasive method for pre-operative functional mapping for patients with brain tumors, especially tumors located near eloquent cortex. Currently, this practice predominantly involves task-based fMRI (T-fMRI). Resting state fMRI (RS-fMRI) offers an alternative with several methodological advantages. Here, we compare group-level analyses of RS-fMRI vs. T-fMRI as methods for language localization. Purpose To contrast RS-fMRI vs. T-fMRI as techniques for localization of language function. Methods We analyzed data obtained in 35 patients who had both T-fMRI and RS-fMRI scans during the course of pre-surgical evaluation. The RS-fMRI data were analyzed using a previously trained resting-state network classifier. The T-fMRI data were analyzed using conventional techniques. Group-level results obtained by both methods were evaluated in terms of two outcome measures: (1) inter-subject variability of response magnitude and (2) sensitivity/ specificity analysis of response topography, taking as ground truth previously reported maps of the language system based on intraoperative cortical mapping as well as meta-analytic maps of language task fMRI responses. Results Both fMRI methods localized major components of the language system (areas of Broca and Wernicke) although not with equal inter-subject consistency. Word-stem completion T-fMRI strongly activated Broca's area but also several task-general areas not specific to language. RS-fMRI provided a more specific representation of the language system.
Neuro-Oncology Practice
Background MRI alone has limited accuracy for delineating tumor margins and poorly predicts the a... more Background MRI alone has limited accuracy for delineating tumor margins and poorly predicts the aggressiveness of gliomas, especially when tumors do not enhance. This study evaluated simultaneous 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (FDOPA)-PET/MRI to define tumor volumes compared to MRI alone more accurately, assessed its role in patient management, and correlated PET findings with histopathology. Methods Ten patients with known or suspected gliomas underwent standard of care surgical resection and/or stereotactic biopsy. FDOPA-PET/MRI was performed prior to surgery, allowing for precise co-registration of PET, MR, and biopsies. The biopsy sites were modeled as 5-mm spheres, and the local FDOPA uptake at each site was determined. Correlations were performed between measures of tumor histopathology, and static and dynamic PET values: standardized uptake values (SUVs), tumor to brain ratios, metabolic tumor volumes, and tracer kinetics at volumes of interest (VOIs) and biopsy ...
Current Problems in Diagnostic Radiology
PLOS ONE
Objectives Primary brain tumors are composed of tumor cells, neural/glial tissues, edema, and vas... more Objectives Primary brain tumors are composed of tumor cells, neural/glial tissues, edema, and vasculature tissue. Conventional MRI has a limited ability to evaluate heterogeneous tumor pathologies. We developed a novel diffusion MRI-based method-Heterogeneity Diffusion Imaging (HDI)-to simultaneously detect and characterize multiple tumor pathologies and capillary blood perfusion using a single diffusion MRI scan. Methods Seven adult patients with primary brain tumors underwent standard-of-care MRI protocols and HDI protocol before planned surgical resection and/or stereotactic biopsy. Twelve tumor sampling sites were identified using a neuronavigational system and recorded for imaging data quantification. Metrics from both protocols were compared between World Health Organization (WHO) II and III tumor groups. Cerebral blood volume (CBV) derived from dynamic susceptibility contrast (DSC) perfusion imaging was also compared with the HDI-derived perfusion fraction. Results The conventional apparent diffusion coefficient did not identify differences between WHO II and III tumor groups. HDI-derived slow hindered diffusion fraction was significantly elevated in the WHO III group as compared with the WHO II group. There was a non-significantly PLOS ONE |
Glioma Imaging
Current strategies for treatment and management of gliomas incorporate molecular markers to indiv... more Current strategies for treatment and management of gliomas incorporate molecular markers to individualize patient care. Physiologic imaging identifies treatment-associated alterations in tissue properties including cellular viability, vascular function, and molecular response. Imaging biomarkers provide a noninvasive approach for early treatment response assessment and are an important tool to individualize patient management. Gliomas are heterogeneous tumors. Parametric response mapping (PRM) is a novel voxel-wise imaging analysis method which directly addresses the issue of tumor heterogeneity. PRM image analysis improves the predictive accuracy of imaging biomarkers in clinical applications including treatment response assessment. A multi-parametric imaging biomarker derived from MR perfusion and diffusion-weighted imaging (DWI) using a PRM analysis method provides early identification of high-grade glioma chemoradiation resistance. Further validation of PRM-derived imaging biomarkers is required prior to routine clinical application as an early treatment response marker.
Blood
Background: By combining the metabolic information of PET with the high soft tissue contrast of M... more Background: By combining the metabolic information of PET with the high soft tissue contrast of MRI, PET/MRI, most often performed with the glucose analogue [18F]fluorodeoxyglucose (FDG), has emerged as a powerful hybrid imaging modality for various oncologic conditions. Multiple myeloma (MM) is an attractive target for FDG-PET/MRI, as both MRI and FDG-PET/CT, when performed separately, have important limitations. For example, diffuse tracer uptake by normal marrow can obscure focal myeloma lesions on FDG-PET, especially in patients receiving marrow-stimulating agents (Hanrahan et al.,RadioGraphics, 2010), while the correlative CT images are less sensitive than MRI for subtle marrow infiltration (Baur-Melnyk et al., AJR, 2008). However, such abnormal marrow signal on MRI can persist despite clinical evidence of disease remission, while the resolution of FDG uptake by focal myeloma lesions closely correlates with clinical metrics of treatment response (Walker et al., Blood, 2004). Th...
Clinical Neurology and Neurosurgery
Neuroimaging Clinics of North America
Clinical Neurology and Neurosurgery
Computed tomographic angiography (CTA) is increasingly utilized to evaluate for traumatic cerebro... more Computed tomographic angiography (CTA) is increasingly utilized to evaluate for traumatic cerebrovascular injury (TCVI). The purpose of this study was to determine the yield, management effect, and risk of stroke or poor outcome of a positive CTA in a large cohort of trauma patients. A retrospective analysis was performed on 1290 consecutive trauma patients that underwent head and/or neck CTA at our level I trauma center from 2006 to 2015. Clinical variables assessed include mechanism of injury, neurological status, CTA findings, subsequent imaging results, patient management, and clinical outcomes. Among 1290 patients who underwent CTA, 200 (15.5%) were positive for TCVI, higher in blunt than penetrating trauma patients. In a generalized linear model, factors that increased likelihood of positive CTA included multiple cervical fractures, fractures with foraminal involvement, gunshot injury, Glasgow Coma Scale ≤ 13, and focal neurological deficit. Excluding cases with these factors lowered the positive rate to 4.3%. Of the 200 CTA-positives, 99 were treated for TCVI and 9 (4.5%) developed a subsequent stroke as compared to 5 (0.5%) in CTA-negative patients (odds ratio 10.2, Fisher exact test, p < 0.001). Risk of death or nursing facility discharge location was also higher in CTA-positive patients, correcting for age and presenting GCS (p < 0.01). CTA had a modest yield in identifying TCVI in this cohort. When positive, CTA influenced management and predicted an increased risk of subsequent stroke and poor outcome.
Neuroimaging clinics of North America, 2017
This article compares resting-state functional magnetic resonance (fMR) imaging with task fMR ima... more This article compares resting-state functional magnetic resonance (fMR) imaging with task fMR imaging for presurgical functional mapping of the sensorimotor (SM) region. Before tumor resection, 38 patients were scanned using both methods. The SM area was anatomically defined using 2 different software tools. Overlap of anatomic regions of interest with task activation maps and resting-state networks was measured in the SM region. A paired t-test showed higher overlap between resting-state maps and anatomic references compared with task activation when using a maximal overlap criterion. Resting state-derived maps are more comprehensive than those derived from task fMR imaging.
Magnetic Resonance Imaging Clinics of North America
PET/MR imaging benefits neurologic clinical care and research by providing spatially and temporal... more PET/MR imaging benefits neurologic clinical care and research by providing spatially and temporally matched anatomic MR imaging, advanced MR physiologic imaging, and metabolic PET imaging. MR imaging sequences and PET tracers can be modified to target physiology specific to a neurologic disease process, with applications in neurooncology, epilepsy, dementia, cerebrovascular disease, and psychiatric and neurologic research. Simultaneous PET/MR imaging provides efficient acquisition of multiple temporally matched datasets, and opportunities for motion correction and improved anatomic assignment of PET data. Current challenges include optimizing MR imaging-based attenuation correction and necessity for dual expertise in PET and MR imaging.