Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 1635

Publication Record

Connections

Intrinsic functional architecture of the non-human primate spinal cord derived from fMRI and electrophysiology.
Wu TL, Yang PF, Wang F, Shi Z, Mishra A, Wu R, Chen LM, Gore JC
(2019) Nat Commun 10: 1416
MeSH Terms: Action Potentials, Animals, Electrophysiological Phenomena, Haplorhini, Humans, Magnetic Resonance Imaging, Physical Stimulation, Reproducibility of Results, Rest, Spinal Cord, Spinal Cord Dorsal Horn, Touch
Show Abstract · Added July 11, 2019
Resting-state functional MRI (rsfMRI) has recently revealed correlated signals in the spinal cord horns of monkeys and humans. However, the interpretation of these rsfMRI correlations as indicators of functional connectivity in the spinal cord remains unclear. Here, we recorded stimulus-evoked and spontaneous spiking activity and local field potentials (LFPs) from monkey spinal cord in order to validate fMRI measures. We found that both BOLD and electrophysiological signals elicited by tactile stimulation co-localized to the ipsilateral dorsal horn. Temporal profiles of stimulus-evoked BOLD signals covaried with LFP and multiunit spiking in a similar way to those observed in the brain. Functional connectivity of dorsal horns exhibited a U-shaped profile along the dorsal-intermediate-ventral axis. Overall, these results suggest that there is an intrinsic functional architecture within the gray matter of a single spinal segment, and that rsfMRI signals at high field directly reflect this underlying spontaneous neuronal activity.
0 Communities
1 Members
0 Resources
MeSH Terms
Registration-based image enhancement improves multi-atlas segmentation of the thalamic nuclei and hippocampal subfields.
Bao S, Bermudez C, Huo Y, Parvathaneni P, Rodriguez W, Resnick SM, D'Haese PF, McHugo M, Heckers S, Dawant BM, Lyu I, Landman BA
(2019) Magn Reson Imaging 59: 143-152
MeSH Terms: Algorithms, Brain Mapping, Hippocampus, Humans, Image Enhancement, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Temporal Lobe, Thalamic Nuclei
Show Abstract · Added March 26, 2019
Magnetic resonance imaging (MRI) is an important tool for analysis of deep brain grey matter structures. However, analysis of these structures is limited due to low intensity contrast typically found in whole brain imaging protocols. Herein, we propose a big data registration-enhancement (BDRE) technique to augment the contrast of deep brain structures using an efficient large-scale non-rigid registration strategy. Direct validation is problematic given a lack of ground truth data. Rather, we validate the usefulness and impact of BDRE for multi-atlas (MA) segmentation on two sets of structures of clinical interest: the thalamic nuclei and hippocampal subfields. The experimental design compares algorithms using T1-weighted 3 T MRI for both structures (and additional 7 T MRI for the thalamic nuclei) with an algorithm using BDRE. As baseline comparisons, a recent denoising (DN) technique and a super-resolution (SR) method are used to preprocess the original 3 T MRI. The performance of each MA segmentation is evaluated by the Dice similarity coefficient (DSC). BDRE significantly improves mean segmentation accuracy over all methods tested for both thalamic nuclei (3 T imaging: 9.1%; 7 T imaging: 15.6%; DN: 6.9%; SR: 16.2%) and hippocampal subfields (3 T T1 only: 8.7%; DN: 8.4%; SR: 8.6%). We also present DSC performance for each thalamic nucleus and hippocampal subfield and show that BDRE can help MA segmentation for individual thalamic nuclei and hippocampal subfields. This work will enable large-scale analysis of clinically relevant deep brain structures from commonly acquired T1 images.
Copyright © 2019 Elsevier Inc. All rights reserved.
0 Communities
1 Members
0 Resources
9 MeSH Terms
Characterization of the hemodynamic response function in white matter tracts for event-related fMRI.
Li M, Newton AT, Anderson AW, Ding Z, Gore JC
(2019) Nat Commun 10: 1140
MeSH Terms: Adult, Cerebral Cortex, Cerebrovascular Circulation, Female, Gray Matter, Healthy Volunteers, Hemodynamics, Hemoglobins, Humans, Magnetic Resonance Imaging, Male, Nerve Net, Oxygen, Pattern Recognition, Visual, Stroop Test, White Matter
Show Abstract · Added March 26, 2019
Accurate estimates of the BOLD hemodynamic response function (HRF) are crucial for the interpretation and analysis of event-related functional MRI data. To date, however, there have been no comprehensive measurements of the HRF in white matter (WM) despite increasing evidence that BOLD signals in WM change after a stimulus. We performed an event-related cognitive task (Stroop color-word interference) to measure the HRF in selected human WM pathways. The task was chosen in order to produce robust, distributed centers of activity throughout the cortex. To measure the HRF in WM, fiber tracts were reconstructed between each pair of activated cortical areas. We observed clear task-specific HRFs with reduced magnitudes, delayed onsets and prolonged initial dips in WM tracts compared with activated grey matter, thus calling for significant changes to current standard models for accurately characterizing the HRFs in WM and for modifications of standard methods of analysis of functional imaging data.
0 Communities
1 Members
0 Resources
16 MeSH Terms
Biophysical model-based parameters to classify tumor recurrence from radiation-induced necrosis for brain metastases.
Narasimhan S, Johnson HB, Nickles TM, Miga MI, Rana N, Attia A, Weis JA
(2019) Med Phys 46: 2487-2496
MeSH Terms: Brain Neoplasms, Humans, Magnetic Resonance Imaging, Models, Biological, Necrosis, Patient-Specific Modeling, Radiation Injuries, Radiosurgery, Recurrence, Retrospective Studies
Show Abstract · Added April 2, 2019
PURPOSE - Stereotactic radiosurgery (SRS) is used for local control treatment of patients with intracranial metastases. As a result of SRS, some patients develop radiation-induced necrosis. Radiographically, radiation-induced necrosis can appear similar to tumor recurrence in magnetic resonance (MR) T -weighted contrast-enhanced imaging, T -weighted MR imaging, and Fluid-Attenuated Inversion Recovery (FLAIR) MR imaging. Radiographic ambiguities often necessitate invasive brain biopsies to determine lesion etiology or cause delayed subsequent therapy initiation. We use a biomechanically coupled tumor growth model to estimate patient-specific model parameters and model-derived measures to noninvasively classify etiology of enhancing lesions in this patient population.
METHODS - In this initial, preliminary retrospective study, we evaluated five patients with tumor recurrence and five with radiation-induced necrosis. Longitudinal patient-specific MR imaging data were used in conjunction with the model to parameterize tumor cell proliferation rate and tumor cell diffusion coefficient, and Dice correlation coefficients were used to quantify degree of correlation between model-estimated mechanical stress fields and edema visualized from MR imaging.
RESULTS - Results found four statistically relevant parameters which can differentiate tumor recurrence and radiation-induced necrosis.
CONCLUSIONS - This preliminary investigation suggests potential of this framework to noninvasively determine the etiology of enhancing lesions in patients who previously underwent SRS for intracranial metastases.
© 2019 American Association of Physicists in Medicine.
0 Communities
1 Members
0 Resources
10 MeSH Terms
Pancreas Volume Declines During the First Year After Diagnosis of Type 1 Diabetes and Exhibits Altered Diffusion at Disease Onset.
Virostko J, Williams J, Hilmes M, Bowman C, Wright JJ, Du L, Kang H, Russell WE, Powers AC, Moore DJ
(2019) Diabetes Care 42: 248-257
MeSH Terms: Adolescent, Adult, Atrophy, Autoantibodies, Case-Control Studies, Child, Child, Preschool, Cohort Studies, Diabetes Mellitus, Type 1, Female, Glucose Tolerance Test, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Organ Size, Pancreas, Time Factors, Young Adult
Show Abstract · Added December 18, 2018
OBJECTIVE - This study investigated the temporal dynamics of pancreas volume and microstructure in children and adolescents with recent-onset type 1 diabetes (T1D) and individuals without diabetes, including a subset expressing autoantibodies associated with the early stages of T1D.
RESEARCH DESIGN AND METHODS - MRI was performed in individuals with recent-onset stage 3 T1D ( = 51; median age 13 years) within 100 days after diagnosis (mean 67 days), 6 months, and 1 year postdiagnosis. Longitudinal MRI measurements were also made in similarly aged control participants ( = 57) and in autoantibody-positive individuals without diabetes ( = 20). The MRI protocol consisted of anatomical imaging to determine pancreas volume and quantitative MRI protocols interrogating tissue microstructure and composition.
RESULTS - Within 100 days of diabetes onset, individuals with T1D had a smaller pancreas (median volume 28.6 mL) than control participants (median volume 48.4 mL; < 0.001), including when normalized by individual weight ( < 0.001). Longitudinal measurements of pancreas volume increased in control participants over the year, consistent with adolescent growth, but pancreas volume declined over the first year after T1D diagnosis ( < 0.001). In multiple autoantibody-positive individuals, the pancreas volume was significantly larger than that of the T1D cohort ( = 0.017) but smaller than that of the control cohort ( = 0.04). Diffusion-weighted MRI showed that individuals with recent-onset T1D had a higher apparent diffusion coefficient ( = 0.012), suggesting a loss of cellular structural integrity, with heterogeneous pancreatic distribution.
CONCLUSIONS - These results indicate that pancreas volume is decreased in stages 1, 2, and 3 of T1D and decreases during the first year after diabetes onset and that this loss of pancreatic volume is accompanied by microstructural changes.
© 2018 by the American Diabetes Association.
1 Communities
3 Members
0 Resources
19 MeSH Terms
Linear Accelerator-Based Stereotactic Radiosurgery for Cranial Intraparenchymal Metastasis of a Malignant Peripheral Nerve Sheath Tumor: Case Report and Review of the Literature.
Fenlon JB, Khattab MH, Ferguson DC, Luo G, Keedy VL, Chambless LB, Kirschner AN
(2019) World Neurosurg 123: 123-127
MeSH Terms: Adult, Brain Neoplasms, Humans, Magnetic Resonance Imaging, Male, Nerve Sheath Neoplasms, Neurofibrosarcoma, Particle Accelerators, Positron-Emission Tomography, Radiosurgery
Show Abstract · Added April 2, 2019
BACKGROUND - Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive soft tissue sarcomas. MPNST intracranial metastasis is exceedingly rare with only 22 documented cases in the literature and, to our knowledge, only 1 case with intraparenchymal brain metastasis. Most have been managed surgically; however, 2 documented cases were treated with Gamma Knife radiosurgery. Excluding this case report, there are no other documented cases of linear accelerator-based stereotactic radiosurgery (SRS) to treat MPNST brain metastasis.
CASE DESCRIPTION - A 41-year-old man with MPNST of the lung initially underwent tumor resection. He developed multiple systemic metastases that were managed with directed radiation therapy. A parietal brain metastasis was treated with linear accelerator-based SRS. Following SRS therapy, the patient was treated with a tropomyosin receptor kinase inhibitor. Complete resolution of brain metastasis was seen on brain magnetic resonance imaging 5 months after treatment with SRS. At 11 months after SRS, there was no evidence of recurrence or progression of the intraparenchymal disease. The patient continued to have stable extracranial disease on his ninth cycle of systemic treatment.
CONCLUSIONS - This report provides important insights into efficacy of linear accelerator-based SRS to treat MPNST brain metastases.
Copyright © 2018 Elsevier Inc. All rights reserved.
0 Communities
1 Members
0 Resources
MeSH Terms
Challenges in diffusion MRI tractography - Lessons learned from international benchmark competitions.
Schilling KG, Daducci A, Maier-Hein K, Poupon C, Houde JC, Nath V, Anderson AW, Landman BA, Descoteaux M
(2019) Magn Reson Imaging 57: 194-209
MeSH Terms: Algorithms, Benchmarking, Brain, Diffusion Tensor Imaging, Humans, Internationality, Neuroimaging, Reproducibility of Results
Show Abstract · Added March 26, 2019
Diffusion MRI (dMRI) fiber tractography has become a pillar of the neuroimaging community due to its ability to noninvasively map the structural connectivity of the brain. Despite widespread use in clinical and research domains, these methods suffer from several potential drawbacks or limitations. Thus, validating the accuracy and reproducibility of techniques is critical for sound scientific conclusions and effective clinical outcomes. Towards this end, a number of international benchmark competitions, or "challenges", has been organized by the diffusion MRI community in order to investigate the reliability of the tractography process by providing a platform to compare algorithms and results in a fair manner, and evaluate common and emerging algorithms in an effort to advance the state of the field. In this paper, we summarize the lessons from a decade of challenges in tractography, and give perspective on the past, present, and future "challenges" that the field of diffusion tractography faces.
Copyright © 2018 Elsevier Inc. All rights reserved.
0 Communities
1 Members
0 Resources
8 MeSH Terms
Protein identification strategies in MALDI imaging mass spectrometry: a brief review.
Ryan DJ, Spraggins JM, Caprioli RM
(2019) Curr Opin Chem Biol 48: 64-72
MeSH Terms: Animals, Equipment Design, Humans, Molecular Imaging, Proteins, Specimen Handling, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Workflow
Show Abstract · Added March 26, 2019
Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is a powerful technology used to investigate the spatial distributions of thousands of molecules throughout a tissue section from a single experiment. As proteins represent an important group of functional molecules in tissue and cells, the imaging of proteins has been an important point of focus in the development of IMS technologies and methods. Protein identification is crucial for the biological contextualization of molecular imaging data. However, gas-phase fragmentation efficiency of MALDI generated proteins presents significant challenges, making protein identification directly from tissue difficult. This review highlights methods and technologies specifically related to protein identification that have been developed to overcome these challenges in MALDI IMS experiments.
Copyright © 2018 Elsevier Ltd. All rights reserved.
0 Communities
1 Members
0 Resources
8 MeSH Terms
Dual excitation wavelength system for combined fingerprint and high wavenumber Raman spectroscopy.
Masson LE, O'Brien CM, Pence IJ, Herington JL, Reese J, van Leeuwen TG, Mahadevan-Jansen A
(2018) Analyst 143: 6049-6060
MeSH Terms: Animals, Cervix Uteri, Collagen, Female, Gelatin, Mice, Phantoms, Imaging, Pregnancy, Spectrum Analysis, Raman, Water
Show Abstract · Added November 26, 2018
A fiber optic probe-based Raman spectroscopy system using a single laser module with two excitation wavelengths, at 680 and 785 nm, has been developed for measuring the fingerprint and high wavenumber regions using a single detector. This system is simpler and less expensive than previously reported configurations of combined fingerprint and high wavenumber Raman systems, and its probe-based implementation facilitates numerous in vivo applications. The high wavenumber region of the Raman spectrum ranges from 2800-3800 cm-1 and contains valuable information corresponding to the molecular vibrations of proteins, lipids, and water, which is complimentary to the biochemical signatures found in the fingerprint region (800-1800 cm-1), which probes DNA, lipids, and proteins. The efficacy of the system is demonstrated by tracking changes in water content in tissue-mimicking phantoms, where Voigtian decomposition of the high wavenumber water peak revealed a correlation between the water content and type of water-tissue interactions in the samples. This dual wavelength system was then used for in vivo assessment of cervical remodeling during mouse pregnancy, a physiologic process with known changes in tissue hydration. The system shows that Raman spectroscopy is sensitive to changes in collagen content in the fingerprint region and hydration state in the high wavenumber region, which was verified using an ex vivo comparison of wet and dry weight. Simultaneous fingerprint and high wavenumber Raman spectroscopy will allow precise in vivo quantification of tissue water content in the high wavenumber region, paired with the high biochemical specificity of the fingerprint region.
0 Communities
1 Members
0 Resources
10 MeSH Terms
Regionally specific volume deficits along the hippocampal long axis in early and chronic psychosis.
McHugo M, Talati P, Woodward ND, Armstrong K, Blackford JU, Heckers S
(2018) Neuroimage Clin 20: 1106-1114
MeSH Terms: Adult, Aged, Bipolar Disorder, Dentate Gyrus, Early Diagnosis, Female, Hippocampus, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Male, Middle Aged, Psychotic Disorders
Show Abstract · Added March 26, 2019
Previous studies in psychosis patients have shown hippocampal volume deficits across anterior and posterior regions or across subfields, but subfield specific changes in volume along the hippocampal long axis have not been examined. Here, we tested the hypothesis that volume changes exist across the hippocampus in chronic psychosis but only the anterior CA region is affected in early psychosis patients. We analyzed structural MRI data from 179 patients with a non-affective psychotic disorder (94 chronic psychosis; 85 early psychosis) and 167 heathy individuals demographically matched to the chronic and early psychosis samples respectively (82 matched to chronic patients; 85 matched to early patients). We measured hippocampal volumes using Freesurfer 6-derived automated segmentation of both anterior and posterior regions and the CA, dentate gyrus, and subiculum subfields. We found a hippocampal volume deficit in both anterior and posterior regions in chronic psychosis, but this deficit was limited to the anterior hippocampus in early psychosis patients. This volume change was more pronounced in the anterior CA subfield of early psychosis patients than in the dentate gyrus or subiculum. Our findings support existing models of psychosis implicating initial CA dysfunction with later progression to other hippocampal regions and suggest that the anterior hippocampus may be an important target for early interventions.
Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.
0 Communities
1 Members
0 Resources
MeSH Terms