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791 results on '"Johnson, Timothy D"'

204. A spatial Bayesian latent factor model for image‐on‐image regression.

Author

Guo, Cui, Kang, Jian, and Johnson, Timothy D.

Subjects
REGRESSION analysis, IMAGE analysis
Abstract

Image‐on‐image regression analysis, using images to predict images, is a challenging task, due to (1) the high dimensionality and (2) the complex spatial dependence structures in image predictors and image outcomes. In this work, we propose a novel image‐on‐image regression model, by extending a spatial Bayesian latent factor model to image data, where low‐dimensional latent factors are adopted to make connections between high‐dimensional image outcomes and image predictors. We assign Gaussian process priors to the spatially varying regression coefficients in the model, which can well capture the complex spatial dependence among image outcomes as well as that among the image predictors. We perform simulation studies to evaluate the out‐of‐sample prediction performance of our method compared with linear regression and voxel‐wise regression methods for different scenarios. The proposed method achieves better prediction accuracy by effectively accounting for the spatial dependence and efficiently reduces image dimensions with latent factors. We apply the proposed method to analysis of multimodal image data in the Human Connectome Project where we predict task‐related contrast maps using subcortical volumetric seed maps. [ABSTRACT FROM AUTHOR]

Published
2022
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206. Multicenter evaluation of parametric response mapping as an indicator of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation

Author

Cheng, Guang‐Shing, Selwa, Katherine E., Hatt, Charles, Ram, Sundaresh, Fortuna, Aleksa B., Guerriero, Margaret, Himelhoch, Ben, McAree, Daniel, Hoffman, Timothy C., Brisson, Joseph, Nazareno, Ryan, Bloye, Kiernan, Johnson, Timothy D., Remberger, Mats, Mattsson, Jonas, Vummidi, Dharshan, Kazerooni, Ella E., Lama, Vibha N., Galban, Stefanie, Boeckh, Michael, Yanik, Gregory A., Galban, Craig J., Cheng, Guang‐Shing, Selwa, Katherine E., Hatt, Charles, Ram, Sundaresh, Fortuna, Aleksa B., Guerriero, Margaret, Himelhoch, Ben, McAree, Daniel, Hoffman, Timothy C., Brisson, Joseph, Nazareno, Ryan, Bloye, Kiernan, Johnson, Timothy D., Remberger, Mats, Mattsson, Jonas, Vummidi, Dharshan, Kazerooni, Ella E., Lama, Vibha N., Galban, Stefanie, Boeckh, Michael, Yanik, Gregory A., and Galban, Craig J.

Abstract

Parametric response mapping (PRM) is a novel computed tomography (CT) technology that has shown potential for assessment of bronchiolitis obliterans syndrome (BOS) after hematopoietic stem cell transplantation (HCT). The primary aim of this study was to evaluate whether variations in image acquisition under real-world conditions affect the PRM measurements of clinically diagnosed BOS. CT scans were obtained retrospectively from 72 HCT recipients with BOS and graft-versus-host disease from Fred Hutchinson Cancer Research Center, Karolinska Institute, and the University of Michigan. Whole lung volumetric scans were performed at inspiration and expiration using site-specific acquisition and reconstruction protocols. PRM and pulmonary function measurements were assessed. Patients with moderately severe BOS at diagnosis (median forced expiratory volume at 1 second [FEV1] 53.5% predicted) had similar characteristics between sites. Variations in site-specific CT acquisition protocols had a negligible effect on the PRM-derived small airways disease (SAD), that is, BOS measurements. PRM-derived SAD was found to correlate with FEV1% predicted and FEV1/ forced vital capacity (R = −0.236, P = .046; and R = −0.689, P < .0001, respectively), which suggests that elevated levels in the PRM measurements are primarily affected by BOS airflow obstruction and not CT scan acquisition parameters. Based on these results, PRM may be applied broadly for post-HCT diagnosis and monitoring of BOS.

Published
2020
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208. A comprehensive assessment of 68Ga-PSMA-11 PET in biochemically recurrent prostate cancer: Results from a prospective multi-center study in 2005 patients.

Author

Abghari-Gerst, Monica, Armstrong, Wesley R., Nguyen, Kathleen, Calais, Jeremie, Czernin, Johannes, Lin, David, Jariwala, Namasvi, Rodnick, Melissa, Hope, Thomas A., Hearn, Jason, Montgomery, Jeffrey S., Alva, Ajjai, Reichert, Zachery R., Spratt, Daniel E., Johnson, Timothy D., Scott, Peter J. H., and Piert, Morand

Published
2021
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211. A comprehensive assessment of 68Ga-PSMA-11 PET in biochemically recurrent prostate cancer: Results from a prospective multi-center study in 2005 patients.

Author

Abghari-Gerst, Monica, Armstrong, Wesley R., Nguyen, Kathleen, Calais, Jeremie, Czernin, Johannes, Lin, David, Jariwala, Namasvi, Rodnick, Melissa, Hope, Thomas A., Hearn, Jason, Montgomery, Jeffrey S., Alva, Ajjai, Reichert, Zachery R., Spratt, Daniel E., Johnson, Timothy D., Scott, Peter J. H., and Piert, Morand

Published
2021
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226. Rheumatic heart disease in Timor‐Leste school students: an echocardiography‐based prevalence study

Author

Davis, Kimberly, primary, Remenyi, Bo, additional, Draper, Anthony DK, additional, Dos Santos, Januario, additional, Bayley, Noel, additional, Paratz, Elizabeth, additional, Reeves, Benjamin, additional, Appelbe, Alan, additional, Cochrane, Andrew, additional, Johnson, Timothy D, additional, Korte, Laura M, additional, Do Rosario, Ivonia M, additional, Da Silva Almeida, Inez T, additional, Roberts, Kathryn V, additional, Carapetis, Jonathan R, additional, and Francis, Joshua R, additional

Published
2018
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227. Multicenter Evaluation of Parametric Response Mapping (PRM) as an Indicator of Bronchiolitis Obliterans Syndrome after Hematopoietic Stem Cell Transplantation (HCT)

Author

Selwa, Katherine, primary, Galban, Craig J., additional, Cheng, Guang-Shing, additional, Mattsson, Jonas, additional, Remberger, Mats, additional, Himelhoch, Ben, additional, McCaree, Daniel, additional, Guerriero, Margaret, additional, Hoffman, Timothy, additional, Brisson, Joseph, additional, Nazareno, Ryan, additional, Bloye, Kiernan, additional, Johnson, Timothy D., additional, Kazerooni, Ella A., additional, and Yanik, Gregory A., additional

Published
2018
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232. Bayesian Spatial Point Process Modeling of Neuroimaging Data

Author

Johnson, Timothy D.

Abstract

Talk given during the "Where’s Your Signal? Explicit Spatial Models to Improve Interpretability and Sensitivity of Neuroimaging Results" workshop at the 2012 Organization for Human Brain Mapping (OHBM) conference in in Beijing, 10-14 June.

Published
2017
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241. Sherman's March to the Sea

Author

Johnson, Timothy D.

Subjects
Sherman's March to the Sea (Book) -- Book reviews, Books -- Book reviews, Humanities, Social sciences
Published
2007

244. CT-Based Local Distribution Metric Improves Characterization of COPD

Author

Hoff, Benjamin A., primary, Pompe, Esther, additional, Galbán, Stefanie, additional, Postma, Dirkje S., additional, Lammers, Jan-Willem J., additional, ten Hacken, Nick H. T., additional, Koenderman, Leo, additional, Johnson, Timothy D., additional, Verleden, Stijn E., additional, de Jong, Pim A., additional, Mohamed Hoesein, Firdaus A. A., additional, van den Berge, Maarten, additional, Ross, Brian D., additional, and Galbán, Craig J., additional

Published
2017
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248. Integrated Multimodal Imaging of Dynamic Bone-Tumor Alterations Associated with Metastatic Prostate Cancer

Author

Brisset, Jean-Christophe, Hoff, Benjamin A., Chenevert, Thomas L., Jacobson, Jon A., Boes, Jennifer L., Galban, Stefanie, Rehemtulla, Alnawaz, Johnson, Timothy D., Pienta, Kenneth J., Galban, Craig J., Meyer, Charles R., Schakel, Timothy, Nicolay, Klaas, Alva, Ajjai S., Hussain, Maha, Ross, Brian D., and Schakel, Tim

Subjects
Male, Oncology, BIOMARKER, Pathology, Osteolysis, Bone density, Bone disease, FUNCTIONAL DIFFUSION MAP, lcsh:Medicine, PROGRESSION, Docetaxel, SDG 3 – Goede gezondheid en welzijn, Multimodal Imaging, 030218 nuclear medicine & medical imaging, Mice, Prostate cancer, 0302 clinical medicine, Bone Density, Prostate, PARAMETRIC RESPONSE MAP, lcsh:Science, Non-U.S. Gov't, Multidisciplinary, Diphosphonates, Research Support, Non-U.S. Gov't, Bone metastasis, Clinical Trial, Tumor Burden, 3. Good health, THERAPY RESPONSE, Treatment Outcome, medicine.anatomical_structure, 030220 oncology & carcinogenesis, ANDROGEN INDEPENDENCE, Taxoids, Research Article, medicine.medical_specialty, GLIOBLASTOMA, Antineoplastic Agents, Bone Neoplasms, Research Support, N.I.H, 03 medical and health sciences, Breast cancer, SDG 3 - Good Health and Well-being, Research Support, N.I.H., Extramural, DW-MRI, Osteoclast, Internal medicine, medicine, Journal Article, Animals, Humans, BREAST-CANCER, Osteoblasts, business.industry, lcsh:R, Prostatic Neoplasms, Extramural, WEIGHTED MRI, medicine.disease, Disease Models, Animal, Diffusion Magnetic Resonance Imaging, lcsh:Q, business
Abstract

Bone metastasis occurs for men with advanced prostate cancer which promotes osseous growth and destruction driven by alterations in osteoblast and osteoclast homeostasis. Patients can experience pain, spontaneous fractures and morbidity eroding overall quality of life. The complex and dynamic cellular interactions within the bone microenvironment limit current treatment options thus prostate to bone metastases remains incurable. This study uses voxel-based analysis of diffusion-weighted MRI and CT scans to simultaneously evaluate temporal changes in normal bone homeostasis along with prostate bone metatastsis to deliver an improved understanding of the spatiotemporal local microenvironment. Dynamic tumor-stromal interactions were assessed during treatment in mouse models along with a pilot prospective clinical trial with metastatic hormone sensitive and castration resistant prostate cancer patients with bone metastases. Longitudinal changes in tumor and bone imaging metrics during delivery of therapy were quantified. Studies revealed that voxel-based parametric response maps (PRM) of DW-MRI and CT scans could be used to quantify and spatially visualize dynamic changes during prostate tumor growth and in response to treatment thereby distinguishing patients with stable disease from those with progressive disease (p

Published
2015

249. A mixed-effects, spatially varying coefficients model with application to multi-resolution functional magnetic resonance imaging data.

Author

Liu, Zhuqing, Bartsch, Andreas J., Berrocal, Veronica J., and Johnson, Timothy D.

Subjects
SPATIAL ability, FUNCTIONAL magnetic resonance imaging, SIGNAL-to-noise ratio, BAYESIAN analysis, SIMULATION methods & models
Abstract

Spatial resolution plays an important role in functional magnetic resonance imaging studies as the signal-to-noise ratio increases linearly with voxel volume. In scientific studies, where functional magnetic resonance imaging is widely used, the standard spatial resolution typically used is relatively low which ensures a relatively high signal-to-noise ratio. However, for pre-surgical functional magnetic resonance imaging analysis, where spatial accuracy is paramount, high-resolution functional magnetic resonance imaging may play an important role with its greater spatial resolution. High spatial resolution comes at the cost of a smaller signal-to-noise ratio. This begs the question as to whether we can leverage the higher signal-to-noise ratio of a standard functional magnetic resonance imaging study with the greater spatial accuracy of a high-resolution functional magnetic resonance imaging study in a pre-operative patient. To answer this question, we propose to regress the statistic image from a high resolution scan onto the statistic image obtained from a standard resolution scan using a mixed-effects model with spatially varying coefficients. We evaluate our model via simulation studies and we compare its performance with a recently proposed model that operates at a single spatial resolution. We apply and compare the two models on data from a patient awaiting tumor resection. Both simulation study results and the real data analysis demonstrate that our newly proposed model indeed leverages the larger signal-to-noise ratio of the standard spatial resolution scan while maintaining the advantages of the high spatial resolution scan. [ABSTRACT FROM AUTHOR]

Published
2019
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250. CT-Based Local Distribution Metric Improves Characterization of COPD

Author

Hoff, Benjamin A, Pompe, Esther, Galbán, Stefanie, Postma, Dirkje S, Lammers, Jan-Willem J, Ten Hacken, Nick H T, Koenderman, Leo, Johnson, Timothy D, Verleden, Stijn E, de Jong, Pim A, Mohamed Hoesein, Firdaus, van den Berge, Maarten, Ross, Brian D, Galbán, Craig J, Hoff, Benjamin A, Pompe, Esther, Galbán, Stefanie, Postma, Dirkje S, Lammers, Jan-Willem J, Ten Hacken, Nick H T, Koenderman, Leo, Johnson, Timothy D, Verleden, Stijn E, de Jong, Pim A, Mohamed Hoesein, Firdaus, van den Berge, Maarten, Ross, Brian D, and Galbán, Craig J

Published
2017

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