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Tomography: a Journal for Imaging Research

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https://www.readbyqxmd.com/read/29675474/brain-tumor-characterization-using-multibiometric-evaluation-of-mri
#1
Faris Durmo, Jimmy Lätt, Anna Rydelius, Silke Engelholm, Sara Kinhult, Krister Askaner, Elisabet Englund, Johan Bengzon, Markus Nilsson, Isabella M Björkman-Burtscher, Thomas Chenevert, Linda Knutsson, Pia C Sundgren
The aim was to evaluate volume, diffusion, and perfusion metrics for better presurgical differentiation between high-grade gliomas (HGG), low-grade gliomas (LGG), and metastases (MET). For this retrospective study, 43 patients with histologically verified intracranial HGG (n = 18), LGG (n = 10), and MET (n = 15) were chosen. Preoperative magnetic resonance data included pre- and post-gadolinium contrast-enhanced T1-weighted fluid-attenuated inversion recover, cerebral blood flow (CBF), cerebral blood volume (CBV), fractional anisotropy, and apparent diffusion coefficient maps used for quantification of magnetic resonance biometrics by manual delineation of regions of interest...
March 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29682610/the-empirical-effect-of-gaussian-noise-in-undersampled-mri-reconstruction
#2
Patrick Virtue, Michael Lustig
In Fourier-based medical imaging, sampling below the Nyquist rate results in an underdetermined system, in which a linear reconstruction will exhibit artifacts. Another consequence is lower signal-to-noise ratio (SNR) because of fewer acquired measurements. Even if one could obtain information to perfectly disambiguate the underdetermined system, the reconstructed image could still have lower image quality than a corresponding fully sampled acquisition because of reduced measurement time. The coupled effects of low SNR and underdetermined system during reconstruction makes it difficult to isolate the impact of low SNR on image quality...
December 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29479563/imaging-lung-cancer-by-using-chemical-exchange-saturation-transfer-mri-with-retrospective-respiration-gating
#3
Kyle M Jones, Carol A Stuehm, Charles C Hsu, Phillip H Kuo, Mark D Pagel, Edward A Randtke
Performing chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) in lung tissue is difficult because of motion artifacts. We, therefore, developed a CEST MRI acquisition and analysis method that performs retrospective respiration gating. Our method used an acquisition scheme with a short 200-millisecond saturation pulse that can accommodate the timing of the breathing cycle, and with saturation applied at frequencies in 0.03-ppm intervals. The Fourier transform of each image was used to calculate the difference in phase angle between adjacent pixels in the longitudinal direction of the respiratory motion...
December 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29308434/high-frequency-4-dimensional-ultrasound-4dus-a-reliable-method-for-assessing-murine-cardiac-function
#4
Frederick W Damen, Alycia G Berman, Arvin H Soepriatna, Jessica M Ellis, Stephen D Buttars, Kristiina L Aasa, Craig J Goergen
In vivo imaging has provided a unique framework for studying pathological progression in various mouse models of cardiac disease. Although conventional short-axis motion-mode (SAX MM) ultrasound and cine magnetic resonance imaging (MRI) are two of the most prevalent strategies used for quantifying cardiac function, there are few notable limitations including imprecision, inaccuracy, and geometric assumptions with ultrasound, or large and costly systems with substantial infrastructure requirements with MRI. Here we present an automated 4-dimensional ultrasound (4DUS) technique that provides comparable information to cine MRI through spatiotemporally synced imaging of cardiac motion...
December 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29457137/correcting-nonpathological-variation-in-longitudinal-parametric-response-maps-of-ct-scans-in-copd-subjects-spiromics
#5
Antonio Fernández-Baldera, Charles R Hatt, Susan Murray, Eric A Hoffman, Ella A Kazerooni, Fernando J Martinez, MeiLan K Han, Craig J Galbán
Small airways disease (SAD) is one of the leading causes of airflow limitations in patients diagnosed with chronic obstructive pulmonary disease (COPD). Parametric response mapping (PRM) of computed tomography (CT) scans allows for the quantification of this previously invisible COPD component. Although PRM is being investigated as a diagnostic tool for COPD, variability in the longitudinal measurements of SAD by PRM has been reported. Here, we show a method for correcting longitudinal PRM data because of non-pathological variations in serial CT scans...
September 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29124128/vascular-deformation-mapping-vdm-of-thoracic-aortic-enlargement-in-aneurysmal-disease-and-dissection
#6
Nicholas S Burris, Benjamin A Hoff, Ella A Kazerooni, Brian D Ross
Thoracic aortic aneurysm is a common and lethal disease that requires regular imaging surveillance to determine timing of surgical repair and prevent major complications such as rupture. Current cross-sectional imaging surveillance techniques, largely based on computed tomography angiography, are focused on measurement of maximal aortic diameter, although this approach is limited to fixed anatomic positions and is prone to significant measurement error. Here we present preliminary results showing the feasibility of a novel technique for assessing change in aortic dimensions, termed vascular deformation mapping (VDM)...
September 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29657962/a-robust-method-for-estimating-b0-inhomogeneity-field-in-the-liver-by-mitigating-fat-signals-and-phase-wrapping
#7
Antonis Matakos, James M Balter, Yue Cao
We developed an optimized and robust method to estimate liver B0 field inhomogeneity for monitoring and correcting susceptibility-induced geometric distortion in magnetic resonance images for precision therapy. A triple-gradient-echo acquisition was optimized for the whole liver B0 field estimation within a single-exhale breath-hold scan on a 3 T scanner. To eliminate chemical-shift artifacts, fat signals were chosen in-phase between 2 echoes with an echo time difference (ΔTE) of 2.3 milliseconds. To avoid phase-wrapping, other 2 echoes provided a large field dynamic range (1/ΔTE) to cover the B0 field inhomogeneity...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28856247/quantitative-image-quality-comparison-of-reduced-and-standard-dose-dual-energy-multiphase-chest-abdomen-and-pelvis-ct
#8
Mario Buty, Ziyue Xu, Aaron Wu, Mingchen Gao, Chelyse Nelson, Georgios Z Papadakis, Uygar Teomete, Haydar Celik, Baris Turkbey, Peter Choyke, Daniel J Mollura, Ulas Bagci, Les R Folio
We present a new image quality assessment method for determining whether reducing radiation dose impairs the image quality of computed tomography (CT) in qualitative and quantitative clinical analyses tasks. In this Institutional Review Board-exempt study, we conducted a review of 50 patients (male, 22; female, 28) who underwent reduced-dose CT scanning on the first follow-up after standard-dose multiphase CT scanning. Scans were for surveillance of von Hippel-Lindau disease (N = 26) and renal cell carcinoma (N = 10)...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28825039/characterizing-the-influence-of-preload-dosing-on-percent-signal-recovery-psr-and-cerebral-blood-volume-cbv-measurements-in-a-patient-population-with-high-grade-glioma-using-dynamic-susceptibility-contrast-mri
#9
Laura C Bell, Leland S Hu, Ashley M Stokes, Samuel C McGee, Leslie C Baxter, C Chad Quarles
With DSC-MRI, contrast agent leakage effects in brain tumors can either be leveraged for percent signal recovery (PSR) measurements or be adequately resolved for accurate relative cerebral blood volume (rCBV) measurements. Leakage effects can be dimished by administration of a preload dose before imaging and/or specific postprocessing steps. This study compares the consistency of both PSR and rCBV measurements as a function of varying preload doses in a retrospective analysis of 14 subjects with high-grade gliomas...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28825038/dynamic-susceptibility-contrast-mri-at-7-t-tail-scaling-analysis-and-inferences-about-field-strength-dependence
#10
Linda Knutsson, Xiang Xu, Freddy Ståhlberg, Peter B Barker, Emelie Lind, Pia C Sundgren, Peter C M van Zijl, Ronnie Wirestam
Dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) following bolus injection of gadolinium contrast agent (CA) is widely used for the estimation of brain perfusion parameters such as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) for both clinical and research purposes. Although it is predicted that DSC-MRI will have superior performance at high magnetic field strengths, to the best of our knowledge, there are no reports of 7 T DSC-MRI in the literature...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28804779/language-mapping-using-t2-prepared-bold-functional-mri-in-the-presence-of-large-susceptibility-artifacts-initial-results-in-patients-with-brain-tumor-and-epilepsy
#11
Jun Hua, Xinyuan Miao, Shruti Agarwal, Chetan Bettegowda, Alfredo Quiñones-Hinojosa, John Laterra, Peter C M Van Zijl, James J Pekar, Jay J Pillai
At present, presurgical functional mapping is the most prevalent clinical application of functional magnetic resonance imaging (fMRI). Signal dropouts and distortions caused by susceptibility effects in the current standard echo planar imaging (EPI)-based fMRI images are well-known problems and pose a major hurdle for the application of fMRI in several brain regions, many of which are related to language mapping in presurgical planning. Such artifacts are particularly problematic in patients with previous surgical resection cavities, craniotomy hardware, hemorrhage, and vascular malformation...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28691102/dce-mri-texture-features-for-early-prediction-of-breast-cancer-therapy-response
#12
Guillaume Thibault, Alina Tudorica, Aneela Afzal, Stephen Y-C Chui, Arpana Naik, Megan L Troxell, Kathleen A Kemmer, Karen Y Oh, Nicole Roy, Neda Jafarian, Megan L Holtorf, Wei Huang, Xubo Song
This study investigates the effectiveness of hundreds of texture features extracted from voxel-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parametric maps for early prediction of breast cancer response to neoadjuvant chemotherapy (NAC). In total, 38 patients with breast cancer underwent DCE-MRI before (baseline) and after the first of the 6-8 NAC cycles. Quantitative pharmacokinetic (PK) parameters and semiquantitative metrics were estimated from DCE-MRI time-course data. The residual cancer burden (RCB) index value was computed based on pathological analysis of surgical specimens after NAC completion...
March 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28649664/quantitative-analysis-of-the-spatial-distribution-of-metastatic-brain-lesions
#13
Ted K Yanagihara, Albert Lee, Tony J C Wang
Brain metastases (BMs) are the most common intracranial malignancy and afflict ~10%-20% of patients with cancer. BMs tend to present at the boundaries of gray and white matter because of the distribution of small vessels. In addition, metastases may not be randomly distributed across gross anatomical regions of the brain, but this has not previously been quantified. We retrospectively analyzed a series of 28 patients with recurrent BMs with a total of 150 lesions. Each lesion was manually defined based on T1 gadolinium-enhanced imaging...
March 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28626797/intrathoracic-fat-measurements-using-multidetector-computed-tomography-mdct-feasibility-and-reproducibility
#14
Jadranka Stojanovska, El-Sayed H Ibrahim, Aamer R Chughtai, Elizabeth A Jackson, Barry H Gross, Jon A Jacobson, Alexander Tsodikov, Brian Daneshvar, Benjamin D Long, Thomas L Chenevert, Ella A Kazerooni
Intrathoracic fat volume, more specifically, epicardial fat volume, is an emerging imaging biomarker of adverse cardiovascular events. The purpose of this work is to show the feasibility and reproducibility of intrathoracic fat volume measurement applied to contrast-enhanced multidetector computed tomography images. A retrospective cohort study of 62 subjects free of cardiovascular disease (55% females, age = 49 ± 11 years) conducted from 2008 to 2011 formed the study group. Intrathoracic fat volume was defined as all fat voxels measuring -50 to -250 Hounsfield Unit within the intrathoracic cavity from the level of the pulmonary artery bifurcation to the heart apex...
March 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28584878/a-population-based-digital-reference-object-dro-for-optimizing-dynamic-susceptibility-contrast-dsc-mri-methods-for-clinical-trials
#15
Natenael B Semmineh, Ashley M Stokes, Laura C Bell, Jerrold L Boxerman, C Chad Quarles
The standardization and broad-scale integration of dynamic susceptibility contrast (DSC)-magnetic resonance imaging (MRI) have been confounded by a lack of consensus on DSC-MRI methodology for preventing potential relative cerebral blood volume inaccuracies, including the choice of acquisition protocols and postprocessing algorithms. Therefore, we developed a digital reference object (DRO), using physiological and kinetic parameters derived from in vivo data, unique voxel-wise 3-dimensional tissue structures, and a validated MRI signal computational approach, aimed at validating image acquisition and analysis methods for accurately measuring relative cerebral blood volume in glioblastomas...
March 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28553660/mri-guided-stereotactic-biopsy-of-murine-gbm-for-spatiotemporal-molecular-genomic-assessment
#16
Stefanie Galbán, Wajd N Al-Holou, Hanxiao Wang, Amanda R Welton, Kevin Heist, Xin Kathy Hu, Roeland Gw Verhaak, Yuan Zhu, Carlos Espinoza, Thomas L Chenevert, Ben A Hoff, Craig J Galbán, Brian D Ross
Brain tumor biopsies that are routinely performed in clinical settings significantly aid in diagnosis and staging. The aim of this study is to develop and evaluate a methodological image-guided approach that would allow for routine sampling of glioma tissue from orthotopic mouse brain tumor models. A magnetic resonance imaging-guided biopsy method is presented to allow for spatially precise stereotaxic sampling of a murine glioma coupled with genome-scale technology to provide unbiased characterization of intra- and intertumoral clonal heterogeneity...
March 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29527574/diffusion-tensor-imaging-for-assessment-of-response-to-neoadjuvant-chemotherapy-in-patients-with-breast-cancer
#17
Lisa J Wilmes, Wen Li, Hee Jung Shin, David C Newitt, Evelyn Proctor, Roy Harnish, Nola M Hylton
In this study, the prognostic significance of tumor metrics derived from diffusion tensor imaging (DTI) was evaluated in patients with locally advanced breast cancer undergoing neoadjuvant therapy. DTI and contrast-enhanced magnetic resonance imaging were acquired at 1.5 T in 34 patients before treatment and after 3 cycles of taxane-based therapy (early treatment). Tumor fractional anisotropy (FA), principal eigenvalues (λ1, λ2, and λ3), and apparent diffusion coefficient (ADC) were estimated for tumor regions of interest drawn on DTI data...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28798963/computational-challenges-and-collaborative-projects-in-the-nci-quantitative-imaging-network
#18
Keyvan Farahani, Jayashree Kalpathy-Cramer, Thomas L Chenevert, Daniel L Rubin, John J Sunderland, Robert J Nordstrom, John Buatti, Nola Hylton
The Quantitative Imaging Network (QIN) of the National Cancer Institute (NCI) conducts research in development and validation of imaging tools and methods for predicting and evaluating clinical response to cancer therapy. Members of the network are involved in examining various imaging and image assessment parameters through network-wide cooperative projects. To more effectively use the cooperative power of the network in conducting computational challenges in benchmarking of tools and methods and collaborative projects in analytical assessment of imaging technologies, the QIN Challenge Task Force has developed policies and procedures to enhance the value of these activities by developing guidelines and leveraging NCI resources to help their administration and manage dissemination of results...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28612050/a-rapid-segmentation-insensitive-digital-biopsy-method-for-radiomic-feature-extraction-method-and-pilot-study-using-ct-images-of-non-small-cell-lung-cancer
#19
Sebastian Echegaray, Viswam Nair, Michael Kadoch, Ann Leung, Daniel Rubin, Olivier Gevaert, Sandy Napel
Quantitative imaging approaches compute features within images' regions of interest. Segmentation is rarely completely automatic, requiring time-consuming editing by experts. We propose a new paradigm, called "digital biopsy," that allows for the collection of intensity- and texture-based features from these regions at least 1 order of magnitude faster than the current manual or semiautomated methods. A radiologist reviewed automated segmentations of lung nodules from 100 preoperative volume computed tomography scans of patients with non-small cell lung cancer, and manually adjusted the nodule boundaries in each section, to be used as a reference standard, requiring up to 45 minutes per nodule...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28480331/comparison-between-3-scan-trace-and-diagonal-body-diffusion-weighted-imaging-acquisitions-a-phantom-and-volunteer-study
#20
Stefanie J Hectors, Mathilde Wagner, Idoia Corcuera-Solano, Martin Kang, Alto Stemmer, Michael A Boss, Bachir Taouli
Diagonal diffusion-weighted imaging (dDWI) uses simultaneous maximized application of 3 orthogonal gradient systems as opposed to sequential acquisition in 3 directions in conventional 3-scan trace DWI (tDWI). Several theoretical advantages of dDWI vs. tDWI include reduced artifacts and increased sharpness. We compared apparent diffusion coefficient (ADC) quantification and image quality between monopolar dDWI and tDWI in a dedicated diffusion phantom (b = 0/500/900/2000 s/mm(2)) and in the abdomen (b = 50/400/800 s/mm(2)) and pelvis (b = 50/1000/1600 s/mm(2)) of 2 male volunteers at 1...
December 2016: Tomography: a Journal for Imaging Research
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