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Tomography: a Journal for Imaging Research

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https://www.readbyqxmd.com/read/30320214/calibration-software-for-quantitative-pet-ct-imaging-using-pocket-phantoms
#1
Dženan Zukić, Darrin W Byrd, Paul E Kinahan, Andinet Enquobahrie
Multicenter clinical trials that use positron emission tomography (PET) imaging frequently rely on stable bias in imaging biomarkers to assess drug effectiveness. Many well-documented factors cause variability in PET intensity values. Two of the largest scanner-dependent errors are scanner calibration and reconstructed image resolution variations. For clinical trials, an increase in measurement error significantly increases the number of patient scans needed. We aim to provide a robust quality assurance system using portable PET/computed tomography "pocket" phantoms and automated image analysis algorithms with the goal of reducing PET measurement variability...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30320213/feasibility-of-deep-learning-based-pet-mr-attenuation-correction-in-the-pelvis-using-only-diagnostic-mr-images
#2
Tyler J Bradshaw, Gengyan Zhao, Hyungseok Jang, Fang Liu, Alan B McMillan
This study evaluated the feasibility of using only diagnostically relevant magnetic resonance (MR) images together with deep learning for positron emission tomography (PET)/MR attenuation correction (deepMRAC) in the pelvis. Such an approach could eliminate dedicated MRAC sequences that have limited diagnostic utility but can substantially lengthen acquisition times for multibed position scans. We used axial T2 and T1 LAVA Flex magnetic resonance imaging images that were acquired for diagnostic purposes as inputs to a 3D deep convolutional neural network...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30320212/improving-b-0-correction-for-ph-weighted-amine-proton-chemical-exchange-saturation-transfer-cest-imaging-by-use-of-k-means-clustering-and-lorentzian-estimation
#3
Jingwen Yao, Dan Ruan, Catalina Raymond, Linda M Liau, Noriko Salamon, Whitney B Pope, Phioanh L Nghiemphu, Albert Lai, Timothy F Cloughesy, Benjamin M Ellingson
Amine chemical exchange saturation transfer (CEST) echoplanar imaging (EPI) provides unique pH and amino acid MRI contrast, enabling sensitive detection of altered microenvironment properties in various diseases. However, CEST contrast is sensitive to static magnetic field (B0 ) inhomogeneities. Here we propose 2 new B0 correction algorithms for use in correcting pH-weighted amine CEST EPI based on k-means clustering and Lorentzian fitting of CEST data: the iterative downsampling estimation using Lorentzian fitting and the 2-stage Lorentzian estimation with 4D polynomial fitting...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30320211/development-of-a-symmetric-echo-planar-spectroscopy-imaging-framework-for-hyperpolarized-13-c-imaging-in-a-clinical-pet-mr-scanner
#4
Abubakr Eldirdiri, Stefan Posse, Lars G Hanson, Rie B Hansen, Pernille Holst, Christina Schøier, Annemarie T Kristensen, Helle Hjorth Johannesen, Andreas Kjaer, Adam E Hansen, Jan Henrik Ardenkjaer-Larsen
Here, we developed a symmetric echo-planar spectroscopic imaging (EPSI) sequence for hyperpolarized 13 C imaging on a clinical hybrid positron emission tomography/magnetic resonance imaging system. The pulse sequence uses parallel reconstruction pipelines to separately reconstruct data from odd-and-even gradient echoes to reduce artifacts from gradient imbalances. The ramp-sampled data in the spatiotemporal frequency space are regridded to compensate for the chemical-shift displacements. Unaliasing of nonoverlapping peaks outside of the sampled spectral width was performed to double the effective spectral width...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30320210/renal-energy-metabolism-following-acute-dichloroacetate-and-2-4-dinitrophenol-administration-assessing-the-cumulative-action-with-hyperpolarized-1-13-c-pyruvate-mri
#5
Lotte Bonde Bertelsen, Per Mose Nielsen, Haiyun Qi, Christian Østergaard Mariager, Jakob Lindhardt, Christoffer Laustsen
Numerous patient groups receive >1 medication and as such represent a potential point of improvement in today's healthcare setup, as the combined or cumulative effects are difficult to monitor in an individual patient. Here we show the ability to monitor the pharmacological effect of 2 classes of medications sequentially, namely, 2,4-dinitrophenol, a mitochondrial uncoupler, and dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, both targeting the oxygen-dependent energy metabolism. We show that although the 2 drugs target 2 different metabolic pathways connected ultimately to oxygen metabolism, we could distinguish the 2 in vivo by using hyperpolarized [1-13 C]pyruvate magnetic resonance imaging...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30320209/meningeal-lymphatic-vessel-flow-runs-countercurrent-to-venous-flow-in-the-superior-sagittal-sinus-of-the-human-brain
#6
Phillip H Kuo, Carol Stuehm, Scott Squire, Kevin Johnson
The recent report of the existence of meningeal lymphatic vessels (MLVs) in human and nonhuman primates used both histology and magnetic resonance imaging (MRI). Many questions about the physiology and function of these lymphatic vessels remain unanswered. Through the combination of appropriately positioned saturation bands and time-of-flight angiography sequences, MRI can resolve direction of flow within vessels without the use of exogenous contrast agent. Six healthy volunteers underwent high-resolution MRI of the MLVs running alongside the superior sagittal sinus to determine the direction of the lymphatic flow...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30320208/virtual-reality-tool-simulates-mri-experience
#7
Richard K J Brown, Sean Petty, Stephanie O'Malley, Jadranka Stojanovska, Matthew S Davenport, Ella A Kazerooni, Daniel Fessahazion
Magnetic resonance imaging (MRI) is an extremely useful tool for the detection and characterization of numerous pathologic processes. Although patients can benefit from the use of MRI, claustrophobia is a major issue in some cases. This fear alone can lead to cancellation of the scanning procedure in some cases and the need for conscious sedation in others. Patient anxiety during the scan can also lead to increased motion-related artifacts on the images with associated degradation of the diagnostic quality of the study...
September 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30206548/manganese-enhanced-magnetic-resonance-imaging-for-detection-and-characterization-of-colorectal-cancers
#8
Liang Wen, Xinan Shi, Liping He, Dan Han
Here, we investigated the diagnostic performance of manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) in colorectal cancer (CRC). The ability of CRC cell lines SW620 and SW480 to uptake Mn was evaluated and compared with a normal colon cell using MEMRI. Subcutaneous xenografts in nude mice underwent MRI examination at tumor sizes of 5, 10, and 15 mm. Contrast enhancement was compared between gadolinium (Gd)- and Mn-enhanced MRI. SW620 and SW480 cell lines took up more Mn2+ than normal cells, resulting in 4...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30206547/what-s-old-is-new-again-the-sacroiliac-joint-as-a-cause-of-lateralizing-low-back-pain
#9
Jennifer Saunders, Mel Cusi, Hans Van der Wall
It has not been easy to identify mechanical failure of the sacroiliac joint (SIJ) with traditional imaging. The integrated model of function (Lee and Vleeming, 1998) suggests that under normal circumstances, form and force closure combined contribute to sacral nutation and "locking" the SIJ for optimal load transfer. This model is supported by clinical evidence and scintigraphic findings that contribute to successful therapy in 80% of cases. Single-photon emission computed tomography and x-ray computed tomography (SPECT-CT), a hybrid device, was used in a study of 1200 patients (64% female and 36% male patients with an average age of 42 years; range, 15-78 years) with a clinical diagnosis of SIJ incompetence (pelvic girdle pain syndrome)...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30206546/dual-energy-ct-derived-iodine-content-and-spectral-attenuation-analysis-of-metastatic-versus-nonmetastatic-lymph-nodes-in-squamous-cell-carcinoma-of-the-oropharynx
#10
Alexandra M Foust, Rukya M Ali, Xuan V Nguyen, Amit Agrawal, Luciano M Prevedello, Eric C Bourekas, Daniel J Boulter
The presence of a single nodal metastasis has significant prognostic and treatment implications for patients with head and neck cancer. This study aims to investigate whether dual-energy computed tomography (DECT)-derived iodine content and spectral attenuation curve analysis can improve detection of nodal metastasis in oropharyngeal carcinoma. Eight patients with newly diagnosed oropharyngeal squamous cell carcinoma and pathologically proven nodal metastatic disease (n = 13 metastatic nodes; n = 16 nonmetastatic nodes) who underwent contrast-enhanced DECT of the neck were retrospectively evaluated...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30206545/characterization-of-an-orthotopic-rat-model-of-glioblastoma-using-multiparametric-magnetic-resonance-imaging-and-bioluminescence-imaging
#11
Trung N T Le, Heeseung Lim, Amanda M Hamilton, Katie M Parkins, Yuanxin Chen, Timothy J Scholl, John A Ronald
Glioblastoma multiforme (GBM) is the most common primary brain tumor, with most patients dying within 15-18 months of diagnosis despite aggressive therapy. Preclinical GBM models are valuable for exploring GBM progression and for evaluating new therapeutics or imaging approaches. The rat C6 glioma model shares similarities with human GBM, and application of noninvasive imaging enables better study of disease progression. Here, multiparametric magnetic resonance imaging (mpMRI) and bioluminescence imaging (BLI) were applied to characterize longitudinal development of orthotopic luciferase-expressing C6 tumors...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30206544/longitudinal-measurements-of-intra-and-extracellular-ph-gradient-in-a-rat-model-of-glioma
#12
Heeseung Lim, Mohammed Albatany, Francisco Martínez-Santiesteban, Robert Bartha, Timothy J Scholl
This study presents the first longitudinal measurement of the intracellular/extracellular pH gradient in a rat glioma model using noninvasive magnetic resonance imaging. The acid-base balance in the brain is tightly controlled by endogenous buffers. Tumors often express a positive pH gradient (pHi - pHe ) compared with normal tissue that expresses a negative gradient. Alkaline pHi in tumor cells increases activity of several enzymes that drive cellular proliferation. In contrast, acidic pHe is established because of increased lactic acid production and subsequent active transport of protons out of the cell...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30206543/complex-vascular-ring-diagnosed-on-cardiovascular-mr-in-a-3-day-old-infant
#13
Jeremy R Burt, Michael Valente, Ali Agha, Kimberly Beavers, Joseph Limback, Michael Fiorino, Rebecca Vicenti, Fiona Tissavirasingham, Khurram Butt, Andrew R Crofton
Prenatal ultrasonography in the early third trimester showed an unusual branching pattern of the right aortic arch. Echocardiography performed 4 h after birth showed the right aortic arch with mirror-image branching, patent ductus arteriosus, and patent foramen ovale. Because the location of the ductus arteriosus was unclear on echocardiography, cardiovascular magnetic resonance imaging was performed 3 days after birth. Advanced techniques including contrast-enhanced time-resolved magnetic resonance angiography and 3D time-of-flight magnetic resonance angiography allowed accurate diagnosis of a vascular ring comprising ascending and descending aorta, right aortic arch with mirror-image branching, and diverticulum of Kommerell giving rise to a left ligamentum arteriosum...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29984313/enhanced-bone-metastases-in-skeletally-immature-mice
#14
Henry R Haley, Nathan Shen, Tonela Qyli, Johanna M Buschhaus, Matthew Pirone, Kathryn E Luker, Gary D Luker
Bone constitutes the most common site of breast cancer metastases either at time of presentation or recurrent disease years after seemingly successful therapy. Bone metastases cause substantial morbidity, including life-threatening spinal cord compression and hypercalcemia. Given the high prevalence of patients with breast cancer, health-care costs of bone metastases (>$20,000 per episode) impose a tremendous economic burden on society. To investigate mechanisms of bone metastasis, we developed femoral artery injection of cancer cells as a physiologically relevant model of bone metastasis...
June 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30042984/feature-tracking-cardiac-mri-reveals-abnormalities-in-ventricular-function-in-patients-with-bicuspid-aortic-valve-and-preserved-ejection-fraction
#15
Nicholas S Burris, Ana Paula S Lima, Michael D Hope, Karen G Ordovas
S ubclinical systolic and diastolic left ventricular (LV) dysfunction has been reported in previous echocardiographic studies on congenital bicuspid aortic valve (BAV). Patients with BAV commonly undergo evaluation with magnetic resonance imaging, and feature-tracking cardiovascular magnetic resonance (CMR-FT) is an emerging technique that assesses myocardial strain using standard cine sequences. This study investigated differences in myocardial strain between patients with BAV with preserved ejection fraction (EF) and controls using CMR-FT...
March 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30042983/assessing-mucosal-inflammation-in-a-dss-induced-colitis-mouse-model-by-mr-colonography
#16
Inbal E Biton, Noa Stettner, Ori Brener, Ayelet Erez, Alon Harmelin, Joel R Garbow
Inflammatory bowel disease (IBD) is characterized by a chronic flaring inflammation of the gastrointestinal tract. To determine disease activity, the inflammatory state of the colon should be assessed. Endoscopy in patients with IBD aids visualization of mucosal inflammation. However, because the mucosa is fragile, there is a significant risk of perforation. In addition, the technique is based on grading of the entire colon, which is highly operator-dependent. An improved, noninvasive, objective magnetic resonance imaging (MRI) technique will effectively assess pathologies in the small intestinal mucosa, more specifically, along the colon, and the bowel wall and surrounding structures...
March 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/30042982/granulomatous-lymphangitis-masquerading-as-relapsed-hodgkin-disease-on-fdg-pet-ct
#17
Mansour Mustafa, Dhruv Patel, Lily Shen, Anita Shetty, Robert Mansberg
A 38-year-old woman with Hodgkin lymphoma was referred for staging fludeoxyglucose (18 F) positron emission tomography/computed tomography (FDG PET/CT) that showed widespread intensely FDG-avid disease in multiple nodal stations above the diaphragm and spleen and extranodal involvement in the lungs and vertebral bodies. She underwent chemotherapy and radiotherapy. Progress FDG PET/CT 5 months later showed significant metabolic and anatomic response. Repeat FDG PET/CT 1 month later was highly suspicious of recurrent disseminated FDG-avid lymphoma in multiple nodal stations above and below the diaphragm, spleen, multiple bones, and lungs...
March 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29984312/simultaneous-estimation-of-bias-and-resolution-in-pet-images-with-a-long-lived-pocket-phantom-system
#18
Paul E Kinahan, Darrin W Byrd, Brian Helba, Kristen A Wangerin, Xiaoxiao Liu, Joshua R Levy, Keith C Allberg, Karthik Krishnan, Ricardo S Avila
A challenge in multicenter trials that use quantitative positron emission tomography (PET) imaging is the often unknown variability in PET image values, typically measured as standardized uptake values, introduced by intersite differences in global and resolution-dependent biases. We present a method for the simultaneous monitoring of scanner calibration and reconstructed image resolution on a per-scan basis using a PET/computed tomography (CT) "pocket" phantom. We use simulation and phantom studies to optimize the design and construction of the PET/CT pocket phantom (120 × 30 × 30 mm)...
March 2018: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/29675474/brain-tumor-characterization-using-multibiometric-evaluation-of-mri
#19
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/30042981/experimental-mri-monitoring-of-renal-blood-volume-fraction-variations-en-route-to-renal-magnetic-resonance-oximetry
#20
Andreas Pohlmann, Kathleen Cantow, Till Huelnhagen, Dirk Grosenick, Joāo Dos Santos Periquito, Laura Boehmert, Thomas Gladytz, Sonia Waiczies, Bert Flemming, Erdmann Seeliger, Thoralf Niendorf
Diagnosis of early-stage acute kidney injury (AKI) will benefit from a timely identification of local tissue hypoxia. Renal tissue hypoxia is an early feature in AKI pathophysiology, and renal oxygenation is increasingly being assessed through T2 *-weighted magnetic resonance imaging (MRI). However, changes in renal blood volume fraction (BVf) confound renal T2 *. The aim of this study was to assess the feasibility of intravascular contrast-enhanced MRI for monitoring renal BVf during physiological interventions that are concomitant with variations in BVf and to explore the possibility of correcting renal T2 * for BVf variations...
December 2017: Tomography: a Journal for Imaging Research
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