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Tomography: a Journal for Imaging Research

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https://www.readbyqxmd.com/read/28090589/spiral-perfusion-imaging-with-consecutive-echoes-spice%C3%A2-for-the-simultaneous-mapping-of-dsc-and-dce-mri-parameters-in-brain-tumor-patients-theory-and-initial-feasibility
#1
Eric S Paulson, Douglas E Prah, Kathleen M Schmainda
Dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) are the perfusion imaging techniques most frequently used to probe the angiogenic character of brain neoplasms. With these methods, T1- and T2/T2*-weighted imaging sequences are used to image the distribution of gadolinium (Gd)-based contrast agents. However, it is well known that Gd exhibits combined T1, T2, and T2* shortening effects in tissue, and therefore, the results of both DCE- and DSC-MRI can be confounded by these opposing effects...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28090588/quantitative-magnetization-transfer-imaging-of-the-breast-at-3-0-t-reproducibility-in-healthy-volunteers
#2
Lori R Arlinghaus, Richard D Dortch, Jennifer G Whisenant, Hakmook Kang, Richard G Abramson, Thomas E Yankeelov
Quantitative magnetization transfer magnetic resonance imaging provides a means for indirectly detecting changes in the macromolecular content of tissue noninvasively. A potential application is the diagnosis and assessment of treatment response in breast cancer; however, before quantitative magnetization transfer imaging can be reliably used in such settings, the technique's reproducibility in healthy breast tissue must be established. Thus, this study aims to establish the reproducibility of the measurement of the macromolecular-to-free water proton pool size ratio (PSR) in healthy fibroglandular (FG) breast tissue...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28083563/the-quantitative-imaging-network-in-precision-medicine
#3
Robert J Nordstrom
Precision medicine is a healthcare model that seeks to incorporate a wealth of patient information to identify and classify disease progression and to provide tailored therapeutic solutions for individual patients. Interventions are based on knowledge of molecular and mechanistic causes, pathogenesis and pathology of disease. Individual characteristics of the patients are then used to select appropriate healthcare options. Imaging is playing an increasingly important role in identifying relevant characteristics that help to stratify patients for different interventions...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066810/dynamic-susceptibility-contrast-mri-quantification-software-tool-development-and-evaluation
#4
Panagiotis Korfiatis, Timothy L Kline, Zachary S Kelm, Rickey E Carter, Leland S Hu, Bradley J Erickson
Relative cerebral blood volume (rCBV) is a magnetic resonance imaging biomarker that is used to differentiate progression from pseudoprogression in patients with glioblastoma multiforme, the most common primary brain tumor. However, calculated rCBV depends considerably on the software used. Automating all steps required for rCBV calculation is important, as user interaction can lead to increased variability and possible inaccuracies in clinical decision-making. Here, we present an automated tool for computing rCBV from dynamic susceptibility contrast-magnetic resonance imaging that includes leakage correction...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066809/deep-feature-transfer-learning-in-combination-with-traditional-features-predicts-survival-among-patients-with-lung-adenocarcinoma
#5
Rahul Paul, Samuel H Hawkins, Yoganand Balagurunathan, Matthew B Schabath, Robert J Gillies, Lawrence O Hall, Dmitry B Goldgof
Lung cancer is the most common cause of cancer-related deaths in the USA. It can be detected and diagnosed using computed tomography images. For an automated classifier, identifying predictive features from medical images is a key concern. Deep feature extraction using pretrained convolutional neural networks (CNNs) has recently been successfully applied in some image domains. Here, we applied a pretrained CNN to extract deep features from 40 computed tomography images, with contrast, of non-small cell adenocarcinoma lung cancer, and combined deep features with traditional image features and trained classifiers to predict short- and long-term survivors...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066808/effect-of-mr-imaging-contrast-thresholds-on-prediction-of-neoadjuvant-chemotherapy-response-in-breast-cancer-subtypes-a-subgroup-analysis-of-the-acrin-6657-i-spy-1-trial
#6
Wen Li, Vignesh Arasu, David C Newitt, Ella F Jones, Lisa Wilmes, Jessica Gibbs, John Kornak, Bonnie N Joe, Laura J Esserman, Nola M Hylton
Functional tumor volume (FTV) measurements by dynamic contrast-enhanced magnetic resonance imaging can predict treatment outcomes for women receiving neoadjuvant chemotherapy for breast cancer. Here, we explore whether the contrast thresholds used to define FTV could be adjusted by breast cancer subtype to improve predictive performance. Absolute FTV and percent change in FTV (ΔFTV) at sequential time-points during treatment were calculated and investigated as predictors of pathologic complete response at surgery...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066807/evaluation-of-cross-calibrated-68-ge-68-ga-phantoms-for-assessing-pet-ct-measurement-bias-in-oncology-imaging-for-single-and-multicenter-trials
#7
Darrin W Byrd, Robert K Doot, Keith C Allberg, Lawrence R MacDonald, Wendy A McDougald, Brian F Elston, Hannah M Linden, Paul E Kinahan
Quantitative PET imaging is an important tool for clinical trials evaluating the response of cancers to investigational therapies. The standardized uptake value, used as a quantitative imaging biomarker, is dependent on multiple parameters that may contribute bias and variability. The use of long-lived, sealed PET calibration phantoms offers the advantages of known radioactivity activity concentration and simpler use than aqueous phantoms. We evaluated scanner and dose calibrator sources from two batches of commercially available kits, together at a single site and distributed across a local multicenter PET imaging network...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066806/automated-segmentation-of-hyperintense-regions-in-flair-mri-using-deep-learning
#8
Panagiotis Korfiatis, Timothy L Kline, Bradley J Erickson
We present a deep convolutional neural network application based on autoencoders aimed at segmentation of increased signal regions in fluid-attenuated inversion recovery magnetic resonance imaging images. The convolutional autoencoders were trained on the publicly available Brain Tumor Image Segmentation Benchmark (BRATS) data set, and the accuracy was evaluated on a data set where 3 expert segmentations were available. The simultaneous truth and performance level estimation (STAPLE) algorithm was used to provide the ground truth for comparison, and Dice coefficient, Jaccard coefficient, true positive fraction, and false negative fraction were calculated...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066805/evaluation-of-soft-tissue-sarcoma-response-to-preoperative-chemoradiotherapy-using-dynamic-contrast-enhanced-magnetic-resonance-imaging
#9
Wei Huang, Brooke R Beckett, Alina Tudorica, Janelle M Meyer, Aneela Afzal, Yiyi Chen, Atiya Mansoor, James B Hayden, Yee-Cheen Doung, Arthur Y Hung, Megan L Holtorf, Torrie J Aston, Christopher W Ryan
This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28044146/bloch-siegert-b1-mapping-improves-accuracy-and-precision-of-longitudinal-relaxation-measurements-in-the-breast-at-3-t
#10
Jennifer G Whisenant, Richard D Dortch, William Grissom, Hakmook Kang, Lori R Arlinghaus, Thomas E Yankeelov
Variable flip angle (VFA) sequences are a popular method of calculating T1 values, which are required in a quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). B1 inhomogeneities are substantial in the breast at 3 T, and these errors negatively impact the accuracy of the VFA approach, thus leading to large errors in the DCE-MRI parameters that could limit clinical adoption of the technique. This study evaluated the ability of Bloch-Siegert B1 mapping to improve the accuracy and precision of VFA-derived T1 measurements in the breast...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27795998/a-classification-system-for-the-spread-of-polymethyl-methacrylate-in-vertebral-bodies-treated-with-vertebral-augmentation
#11
Joseph Frankl, Michael P Sakata, Gagandeep Choudhary, Seung Hur, Andrew Peterson, Charles T Hennemeyer
In this study, we develop a classification system for describing polymethyl methacrylate (PMMA) spread in vertebral bodies after kyphoplasty or vertebroplasty for vertebral compression fractures (VCFs) and for assessing whether PMMA spread varies between operators, VCF etiology, or vertebral level. Intraoperative fluoroscopic images of 198 vertebral levels were reviewed in 137 patients (women, 84; men, 53; mean age, 75.8 ± 12.5; and those with a diagnosis of osteoporosis, 63%) treated with kyphoplasty between January 01, 2015 and May 31, 2015 at a single center to create a 5-class descriptive system...
September 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27774518/magnetic-resonance-imaging-based-radiomic-profiles-predict-patient-prognosis-in-newly-diagnosed-glioblastoma-before-therapy
#12
Sean D McGarry, Sarah L Hurrell, Amy L Kaczmarowski, Elizabeth J Cochran, Jennifer Connelly, Scott D Rand, Kathleen M Schmainda, Peter S LaViolette
Magnetic resonance imaging (MRI) is used to diagnose and monitor brain tumors. Extracting additional information from medical imaging and relating it to a clinical variable of interest is broadly defined as radiomics. Here, multiparametric MRI radiomic profiles (RPs) of de novo glioblastoma (GBM) brain tumors is related with patient prognosis. Clinical imaging from 81 patients with GBM before surgery was analyzed. Four MRI contrasts were aligned, masked by margins defined by gadolinium contrast enhancement and T2/fluid attenuated inversion recovery hyperintensity, and contoured based on image intensity...
September 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27752544/hypoxia-imaging-with-pet-correlates-with-antitumor-activity-of-the-hypoxia-activated-prodrug-evofosfamide-th-302-in-rodent-glioma-models
#13
Ashley M Stokes, Charles P Hart, C Chad Quarles
High-grade gliomas are often characterized by hypoxia, which is associated with both poor long-term prognosis and therapy resistance. The adverse role hypoxia plays in treatment resistance and disease progression has led to the development of hypoxia imaging methods and hypoxia-targeted treatments. Here, we determined the tumor hypoxia and vascular perfusion characteristics of 2 rat orthotopic glioma models using 18-fluoromisonidozole positron emission tomography. In addition, we determined tumor response to the hypoxia-activated prodrug evofosfamide (TH-302) in these rat glioma models...
September 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27738656/combination-of-an-integrin-targeting-nir-tracer-and-an-ultrasensitive-spectroscopic-device-for-intraoperative-detection-of-head-and-neck-tumor-margins-and-metastatic-lymph-nodes
#14
Younghyoun Yoon, Aaron M Mohs, Michael C Mancini, Shuming Nie, Hyunsuk Shim
Despite major advances in targeted drug therapy and radiation therapy, surgery remains the most effective treatment for most solid tumors. The single most important predictor of patient survival is a complete surgical resection of the primary tumor, draining lymph nodes, and metastatic lesions. Presently, however, 20%-30% of patients with head and neck cancer who undergo surgery still leave the operating room without complete resection because of missed lesions. Thus, major opportunities exist to develop advanced imaging tracers and intraoperative instrumentation that would allow surgeons to visualize microscopic tumors during surgery...
September 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28018967/fast-pad%C3%A3-transform-accelerated-csi-for-hyperpolarized-mrs
#15
Esben Szocska Søvsø Hansen, Sun Kim, Jack J Miller, Marcus Geferath, Glen Morrell, Christoffer Laustsen
The fast Padé transform (FPT) is a method of spectral analysis that can be used to reconstruct nuclear magnetic resonance spectra from truncated free induction decay signals with superior robustness and spectral resolution compared with conventional Fourier analysis. The aim of this study is to show the utility of FPT in reducing of the scan time required for hyperpolarized (13)C chemical shift imaging (CSI) without sacrificing the ability to resolve a full spectrum. Simulations, phantom, and in vivo hyperpolarized [1-(13)C] pyruvate CSI data were processed with FPT and compared with conventional analysis methods...
June 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27570835/imaging-renal-urea-handling-in-rats-at-millimeter-resolution-using-hyperpolarized-magnetic-resonance-relaxometry
#16
Galen D Reed, Cornelius von Morze, Alan S Verkman, Bertram L Koelsch, Myriam M Chaumeil, Michael Lustig, Sabrina M Ronen, Robert A Bok, Jeff M Sands, Peder E Z Larson, Zhen J Wang, Jan Henrik Ardenkjær Larsen, John Kurhanewicz, Daniel B Vigneron
In vivo spin spin relaxation time (T2) heterogeneity of hyperpolarized [(13)C,(15)N2]urea in the rat kidney was investigated. Selective quenching of the vascular hyperpolarized (13)C signal with a macromolecular relaxation agent revealed that a long-T2 component of the [(13)C,(15)N2]urea signal originated from the renal extravascular space, thus allowing the vascular and renal filtrate contrast agent pools of the [(13)C,(15)N2]urea to be distinguished via multi-exponential analysis. The T2 response to induced diuresis and antidiuresis was performed with two imaging agents: hyperpolarized [(13)C,(15)N2]urea and a control agent hyperpolarized bis-1,1-(hydroxymethyl)-1-(13)C-cyclopropane-(2)H8...
June 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27547821/improved-localisation-for-2-hydroxyglutarate-detection-at-3t-using-long-te-semi-laser
#17
Adam Berrington, Natalie L Voets, Puneet Plaha, Sarah J Larkin, James Mccullagh, Richard Stacey, Muhammed Yildirim, Christopher J Schofield, Peter Jezzard, Tom Cadoux-Hudson, Olaf Ansorge, Uzay E Emir
2-hydroxyglutarate (2-HG) has emerged as a biomarker of tumour cell IDH mutations that may enable the differential diagnosis of glioma patients. At 3 Tesla, detection of 2-HG with magnetic resonance spectroscopy is challenging because of metabolite signal overlap and a spectral pattern modulated by slice selection and chemical shift displacement. Using density matrix simulations and phantom experiments, an optimised semi-LASER scheme (TE = 110 ms) improves localisation of the 2-HG spin system considerably compared to an existing PRESS sequence...
June 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27489883/a-systematic-pipeline-for-the-objective-comparison-of-whole-brain-spectroscopic-mri-with-histology-in-biopsy-specimens-from-grade-iii-glioma
#18
J Scott Cordova, Saumya S Gurbani, Jeffrey J Olson, Zhongxing Liang, Lee A D Cooper, Hui-Kuo G Shu, Eduard Schreibmann, Stewart G Neill, Constantinos G Hadjipanayis, Chad A Holder, Hyunsuk Shim
The diagnosis, prognosis, and management of patients with gliomas are largely dictated by the pathological analysis of tissue biopsied from a selected region within the lesion. However, due to the heterogeneous and infiltrative nature of gliomas, identifying the optimal region for biopsy with conventional magnetic resonance imaging (MRI) can be quite difficult. This is especially true for low grade gliomas, which often are non-enhancing tumors. To improve the management of patients with these tumors, the field of neuro-oncology requires an imaging modality that can specifically identify a tumor's most anaplastic/aggressive region(s) for biopsy targeting...
June 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27478872/co-registration-of-bioluminescence-tomography-computed-tomography-and-magnetic-resonance-imaging-for-multimodal-in-vivo-stem-cell-tracking
#19
Moussa Chehade, Amit K Srivastava, Jeff W M Bulte
We present a practical approach for co-registration of bioluminescence tomography (BLT), computed tomography (CT), and magnetic resonance (MR) images. To this end, we developed a customized animal shuttle composed of non-fluorescent, MR-compatible Delrin plastic that fits a commercially available MR surface coil. Mouse embryonic stem cells (mESCs) were transfected with the luciferase gene and labeled with superparamagnetic iron oxide (SPIO) nanoparticles. Cells were stereotaxically implanted in mouse brain and imaged weekly for 4 weeks with BLI (IVIS Spectrum CT scanner) and MRI (11...
June 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/27478871/imaging-sensitivity-of-quiescent-cancer-cells-to-metabolic-perturbations-in-bone-marrow-spheroids
#20
Stephen P Cavnar, Annie Xiao, Anne E Gibbons, Andrew D Rickelmann, Taylor Neely, Kathryn E Luker, Shuichi Takayama, Gary D Luker
Malignant cells from breast cancer and other common cancers such as prostate and melanoma may persist in bone marrow as quiescent, non-dividing cells that remain viable for years or even decades before resuming proliferation to cause recurrent disease. This phenomenon, referred to clinically as tumor dormancy, poses tremendous challenges to curing patients with breast cancer. Quiescent tumor cells resist chemotherapy drugs that predominantly target proliferating cells, limiting success of neo-adjuvant and adjuvant therapies...
June 2016: Tomography: a Journal for Imaging Research
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