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Hounsfield Units (HU)

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https://www.readbyqxmd.com/read/28091837/peritoneal-fluid-of-low-ct-hounsfield-units-as-a-screening-criterion-for-traumatic-bowel-perforation
#1
Yon-Cheong Wong, Li-Jen Wang, Cheng-Hsien Wu, Huan-Wu Chen, Being-Chuan Lin, Yu-Pao Hsu
PURPOSE: To investigate whether peritoneal fluid of low CT Hounsfield units is an important screening criterion for traumatic bowel perforation. MATERIALS AND METHODS: We performed a retrospective study on two cohorts of blunt trauma patients who had peritoneal fluid. Intravenous and oral contrast was used for the first cohort (61 patients) as opposed to intravenous contrast only for the second cohort (60 patients). We compared the CT Hounsfield units of peritoneal fluid with bowel perforation...
January 13, 2017: Japanese Journal of Radiology
https://www.readbyqxmd.com/read/28089254/volumetric-analysis-of-carotid-plaque-components-and-cerebral-microbleeds-a-correlative-study
#2
Luca Saba, Roberto Sanfilippo, Michele di Martino, Michele Porcu, Roberto Montisci, Pierleone Lucatelli, Michele Anzidei, Marco Francone, Jasjit S Suri
PURPOSE: The purpose of this work was to explore the association between carotid plaque volume (total and the subcomponents) and cerebral microbleeds (CMBs). MATERIALS AND METHODS: Seventy-two consecutive (male 53; median age 64) patients were retrospectively analyzed. Carotid arteries were studied by using a 16-detector-row computed tomography scanner whereas brain was explored with a 1.5 Tesla system. CMBs were studied using a T2*-weighted gradient-recalled echo sequence...
January 11, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28072512/a-high-performance-hybrid-bismuth-carbon-nanotube-based-contrast-agent-for-x-ray-ct-imaging
#3
Mayra Hernández-Rivera, Ish Kumar, Stephen Y Cho, Benjamin Y Cheong, Merlyn X Pulikkathara, Sakineh E Moghaddam, Kenton Herbert Whitmire, Lon J Wilson
Carbon nanotubes (CNTs) have been used for a plethora of biomedical applications including their use as delivery vehi-cles for drugs, imaging agents, proteins, DNA, and other materials. Here we describe the synthesis and characterization of a new CNT-based contrast agent (CA) for X-ray computed tomography (CT) imaging. The CA is a hybrid material derived from ultra-short single-walled carbon nanotubes (20-80 nm long, US-tubes) and Bi(III) oxo-salicylate clusters with four Bi(III) ions per cluster (Bi4C). The element bismuth was chosen over iodine, which is the conventional element used for CT CAs in the clinic today, due to its high X-ray attenuation capability and its low toxicity, which make bismuth a more promising element for new CT CA design...
January 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28065375/accessory-spleen-versus-lymph-node-value-of-iodine-quantification-with-dual-energy-computed-tomography
#4
Sebastian Winklhofer, Wei-Ching Lin, Jack W Lambert, Benjamin M Yeh
OBJECTIVES: To evaluate whether iodine quantification with Dual-Energy Computed Tomography (DECT) improves the differentiation of accessory spleens (AS) from lymph nodes (LN) compared to CT number measurements. METHODS: Abdominal DECT images of 75 patients with either AS (n=35) or LN (n=48) (benign entity) were retrospectively evaluated. Hounsfield Units (HU) and iodine concentrations of AS, LN and the main spleen were measured. Receiver operating characteristics (ROC) were performed to calculate an optimal threshold for distinguishing AS from LN...
February 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28060856/hiv-infection-is-associated-with-increased-fatty-infiltration-of-the-thigh-muscle-with-aging-independent-of-fat-distribution
#5
Javzandulam Natsag, Kristine M Erlandson, Deborah E Sellmeyer, Sabina A Haberlen, Joseph Margolick, Lisa P Jacobson, Frank J Palella, Susan L Koletar, Jordan E Lake, Wendy S Post, Todd T Brown
BACKGROUND: Lower muscle density on computed tomography (CT) provides a measure of fatty infiltration of muscle, an aspect of muscle quality that has been associated with metabolic abnormalities, weakness, decreased mobility, and increased fracture risk in older adults. We assessed the cross-sectional relationship between HIV serostatus, age, thigh muscle attenuation, and thigh muscle cross-sectional area (CSA). METHODS: Mean CT-quantified Hounsfield units (HU) of the thigh muscle bundle and CSA were evaluated in 368 HIV-infected and 145 HIV-uninfected men enrolled in the Multicenter AIDS Cohort Study (MACS) Cardiovascular Substudy using multivariable linear regression...
2017: PloS One
https://www.readbyqxmd.com/read/28060414/standardizing-ct-lung-density-measure-across-scanner-manufacturers
#6
Huaiyu Heather Chen-Mayer, Matthew K Fuld, Bernice Hoppel, Philip F Judy, Jered P Sieren, Junfeng Guo, David A Lynch, Antonio Possolo, Sean B Fain
PURPOSE: Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number histograms, and are typically a quantity specifying either the percentage of voxels with CT numbers below a threshold, or a single CT number below which a fixed relative lung volume, nth percentile, falls...
January 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28050639/cerebral-bone-subtraction-ct-angiography-using-80%C3%A2-kvp-and-sinogram-affirmed-iterative-reconstruction-contrast-medium-and-radiation-dose-reduction-with-improvement-of-image-quality
#7
Yasunori Nagayama, Takeshi Nakaura, Akinori Tsuji, Joji Urata, Mitsuhiro Furusawa, Hideaki Yuki, Kenichiro Hirarta, Seitaro Oda, Masafumi Kidoh, Daisuke Utsunomiya, Yasuyuki Yamashita
INTRODUCTION: The purpose of this study was to evaluate the feasibility of a contrast medium (CM), radiation dose reduction protocol for cerebral bone-subtraction CT angiography (BSCTA) using 80-kVp and sinogram-affirmed iterative reconstruction (SAFIRE). METHODS: Seventy-five patients who had undergone BSCTA under the 120- (n = 37) or the 80-kVp protocol (n = 38) were included. CM was 370 mgI/kg for the 120-kVp and 296 mgI/kg for the 80-kVp protocol; the 120- and the 80-kVp images were reconstructed with filtered back-projection (FBP) and SAFIRE, respectively...
January 3, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28048911/su-g-iep1-06-estimating-relative-tissue-density-from-quantitative-mr-images-a-novel-perspective-for-mri-only-heterogeneity-corrected-dose-calculation
#8
A Soliman, M Hashemi, H Safigholi, E Tchistiakova, W Song
PURPOSE: To explore the feasibility of extracting the relative density from quantitative MRI measurements as well as estimate a correlation between the extracted measures and CT Hounsfield units. METHODS: MRI has the ability to separate water and fat signals, producing two separate images for each component. By performing appropriate corrections on the separated images, quantitative measurement of water and fat mass density can be estimated. This work aims to test this hypothesis on 1...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048729/su-f-t-219-verification-of-the-accuracy-of-a-relative-stopping-power-rsp-to-hounsfield-unit-hu-calibration-curve-produced-for-proton-treatment-planning-using-ebt3-gafchromic-film-dosimetry
#9
E Schnell, C Ferreira, S Ahmad, T De La Fuente Herman
PURPOSE: Accuracy of a RSP-HU calibration curve produced for proton treatment planning is tested by comparing the treatment planning system dose grid to physical doses delivered on film by a Mevion S250 double-scattering proton unit. METHODS: A single batch of EBT3 Gafchromic film was used for calibration and measurements. The film calibration curve was obtained using Mevion proton beam reference option 20 (15cm range, 10cm modulation). Paired films were positioned at the center of the spread out Bragg peak (SOBP) in solid water...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048674/su-f-t-215-an-investigation-of-multi-scanner-ct-hounsfield-unit-calibration-for-pencil-beam-scanning-proton-therapy-using-3d-gamma-analysis
#10
J Zhang, X Li, G Liu, Q Liu, J Liang, X Ding
PURPOSE: We compare and investigate the dosimetric impacts on pencil beam scanning (PBS) proton treatment plans generated with CT calibration curves from four different CT scanners and one averaged 'global' CT calibration curve. METHODS: The four CT scanners are located at three different hospital locations within the same health system. CT density calibration curves were collected from these scanners using the same CT calibration phantom and acquisition parameters...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048563/we-ab-207b-05-correlation-of-normal-lung-density-changes-with-dose-after-stereotactic-body-radiotherapy-sbrt-for-early-stage-lung-cancer
#11
Q Wu, S Devpura, K Feghali, C Liu, M Ajlouni, B Movsas, I Chetty
PURPOSE: To investigate correlation of normal lung CT density changes with dose accuracy and outcome after SBRT for patients with early stage lung cancer. METHODS: Dose distributions for patients originally planned and treated using a 1-D pencil beam-based (PB-1D) dose algorithm were retrospectively recomputed using algorithms: 3-D pencil beam (PB-3D), and model-based METHODS: AAA, Acuros XB (AXB), and Monte Carlo (MC). Prescription dose was 12 Gy × 4 fractions...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048559/we-ab-202-05-validation-of-lung-stress-maps-for-ct-ventilation-imaging
#12
G Cazoulat, J Kipritidis, S Siva, M Hofman, S Jolly, M Matuszak, J Balter, P Keall, K Brock
PURPOSE: To date, lung CT-ventilation imaging has been based on quantification of local breathing-induced changes in Hounsfield Units (HU) or volume. This work investigates the use of a stress map resulting from a biomechanical deformable image registration (DIR) algorithm as a metric of the ventilation function. METHOD: Eight lung cancer patients presenting different kinds of ventilation defects were retrospectively analyzed. Additionally, to the 4DCT acquired for radiotherapy planning, five of them had PET and three had SPECT imaging following inhalation of Ga-68 and Tc-99m, respectively...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048440/su-g-iep2-12-the-effect-of-iterative-reconstruction-and-ct-tube-voltage-on-hounsfield-unit-values-of-iodinated-contrast
#13
K Ogden, K Greene-Donnelly, D Vallabhaneni, E Scalzetti
PURPOSE: To investigate the effects of changing iterative reconstruction strength and tube voltage on Hounsfield Unit (HU) values of varying concentrations of Iodinated contrast medium in a phantom. METHOD: Iodinated contrast (Omnipaque 300, GE Healthcare, Princeton NJ) was diluted with distilled water to concentrations of 0.6, 0.9, 1.8, 3.6, 7.2, and 10.8 mg/mL of Iodine. The solutions were scanned in a patient equivalent water phantom on two MDCT scanners: VCT 64 slice (GE Medical Systems, Waukesha, WI) and an Aquilion One 320 slice scanner (Toshiba America Medical Systems, Tustin CA)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048216/su-f-j-220-micro-ct-based-quantification-of-mouse-brain-vasculature-the-effects-of-acquisition-technique-and-contrast-material
#14
C Tipton, M Lamba, Z Qi, K LaSance, C Tipton
PURPOSE: Cognitive impairment from radiation therapy to the brain may be linked to the loss of total blood volume in the brain. To account for brain injury, it is crucial to develop an understanding of blood volume loss as a result of radiation therapy. This study investigates µCT based quantification of mouse brain vasculature, focusing on the effect of acquisition technique and contrast material. METHODS: Four mice were scanned on a µCT scanner (Siemens Inveon)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048197/su-f-j-175-evaluation-of-metal-artifact-reduction-algorithms-in-computed-tomography-and-their-application-to-radiation-therapy-treatment-planning
#15
H Norris, D Rangaraj, S Kim
PURPOSE: High-Z (metal) implants in CT scans cause significant streak-like artifacts in the reconstructed dataset. This results in both inaccurate CT Hounsfield units for the tissue as well as obscuration of the target and organs at risk (OARs) for radiation therapy planning. Herein we analyze two metal artifact reduction algorithms: GE's Smart MAR and a Metal Deletion Technique (MDT) for geometric and Hounsfield Unit (HU) accuracy. METHODS: A CT-to-electron density phantom, with multiple inserts of various densities and a custom Cerrobend insert (Zeff=76...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048179/su-f-r-54-ct-texture-based-early-tumor-treatment-response-assessment-during-radiation-therapy-delivery-small-cell-versus-non-small-cell-lung-cancers
#16
J Paul, E Gore, X Li
PURPOSE: Tumor treatment response may potentially be assessed during radiation therapy (RT) by analyzing changes in CT-textures. We investigated the different early RT-responses between small cell (SCLC) and non-small cell lung cancer (NSCLC) as assessed by CT-texture. METHODS: Daily diagnostic-quality CT acquired during routine CT-guided RT using a CT-on-Rails for 13-NSCLC and 5-SCLC patients were analyzed. These patient had ages ranging from 45-78 and 38-63 years, respectively, for NSCLC and SCLC groups, and tumor-stages ranging from T2-T4, and were treated with either RT or chemotherapy and RT with 45-66Gy/ 20-34 fractions...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048151/su-f-r-43-recursive-k-means-filter-for-preserving-signals-of-interest
#17
A Chu, P Yan, R Shih, C Wuu
PURPOSE: To use recursive cluster analysis to filter noises and artifacts out of useful signals. The method was applied to CT or CBCT for preserving interested low Hounsfield Unit (HU) signals such as lung tissues while the HU of lung tissues is often overlapped with CT (or CBCT) artifacts. METHODS: Cluster analysis is to search for the similarity among data points, which could employ multi-dimensional techniques. For our purpose, we searched for a robust, fast, and automatic process for sorting interested low HU object in CT, Therefore, 1-D cluster analysis is suitable for the purpose...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048069/su-f-t-220-validation-of-hounsfield-unit-to-stopping-power-ratio-calibration-used-for-dose-calculation-in-proton-radiotherapy
#18
J Polf, H Chung, K Langen
PURPOSE: To validate the stoichiometric calibration of the Hounsfield Unit (HU) to Stopping Power Ratio (SPR) calibration used to commission a commercial treatment planning system (TPS) for proton radiotherapy dose calculation. METHODS AND MATERIALS: The water equivalent thickness (WET) of several individual pig tissues (lung, fat, muscle, liver, intestine, rib, femur), mixed tissue samples (muscle/rib, ice/femur, rib/air cavity/muscle), and an intact pig head were measured with a multi-layer ionization chamber (MLIC)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048046/su-f-j-74-high-z-geometric-integrity-and-beam-hardening-artifact-assessment-using-a-retrospective-metal-artifact-reduction-mar-reconstruction-algorithm
#19
K Woods, D DiCostanzo, N Gupta
PURPOSE: To test the efficacy of a retrospective metal artifact reduction (MAR) reconstruction algorithm for a commercial computed tomography (CT) scanner for radiation therapy purposes. METHODS: High Z geometric integrity and artifact reduction analysis was performed with three phantoms using General Electric's (GE) Discovery CT. The three phantoms included: a Computerized Imaging Reference Systems (CIRS) electron density phantom (Model 062) with a 6.5 mm diameter titanium rod insert, a custom spine phantom using Synthes Spine hardware submerged in water, and a dental phantom with various high Z fillings submerged in water...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047938/su-f-t-332-dose-impact-of-rectal-gas-on-prostate-vmat
#20
M Sasaki, H Ikushima, M Tominaga, T Kawashita, T Kamomae, R Bando, K Sakuragawa, M Oita
PURPOSE: The aim of this study to evaluate influence of rectal gas on dose distribution during prostate VMAT. METHODS: Our subjects were 10 patients who have received VMAT for prostate cancer at our hospital. In this study, we made four types of VMAT plan. The angles of rotation were as follows: clockwise from 181-179° and 179-181° (Full arc), clockwise from 200-160° and counter-clockwise from 160-200° (Partial arc1), clockwise from 220- 140° and counter-clockwise from 140-220° (Partial arc2), clockwise from 240-120° and counter-clockwise from 120-240° (Partial arc3)...
June 2016: Medical Physics
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