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Sample records for comparative imaging study

  1. Scatterometry or imaging overlay: a comparative study

    Science.gov (United States)

    Hsu, Simon C. C.; Pai, Yuan Chi; Chen, Charlie; Yu, Chun Chi; Hsing, Henry; Wu, Hsing-Chien; Kuo, Kelly T. L.; Amir, Nuriel

    2015-03-01

    Most fabrication facilities today use imaging overlay measurement methods, as it has been the industry's reliable workhorse for decades. In the last few years, third-generation Scatterometry Overlay (SCOL™) or Diffraction Based Overlay (DBO-1) technology was developed, along another DBO technology (DBO-2). This development led to the question of where the DBO technology should be implemented for overlay measurements. Scatterometry has been adopted for high volume production in only few cases, always with imaging as a backup, but scatterometry overlay is considered by many as the technology of the future. In this paper we compare imaging overlay and DBO technologies by means of measurements and simulations. We outline issues and sensitivities for both technologies, providing guidelines for the best implementation of each. For several of the presented cases, data from two different DBO technologies are compared as well, the first with Pupil data access (DBO-1) and the other without pupil data access (DBO-2). Key indicators of overlay measurement quality include: layer coverage, accuracy, TMU, process robustness and robustness to process changes. Measurement data from real cases across the industry are compared and the conclusions are also backed by simulations. Accuracy is benchmarked with reference OVL, and self-consistency, showing good results for Imaging and DBO-1 technology. Process sensitivity and metrology robustness are mostly simulated with MTD (Metrology Target Designer) comparing the same process variations for both technologies. The experimental data presented in this study was done on ten advanced node layers and three production node layers, for all phases of the IC fabrication process (FEOL, MEOL and BEOL). The metrology tool used for most of the study is KLA-Tencor's Archer 500LCM system (scatterometry-based and imaging-based measurement technologies on the same tool) another type of tool is used for DBO-2 measurements. Finally, we conclude that

  2. Comparative study of image restoration techniques in forensic image processing

    Science.gov (United States)

    Bijhold, Jurrien; Kuijper, Arjan; Westhuis, Jaap-Harm

    1997-02-01

    In this work we investigated the forensic applicability of some state-of-the-art image restoration techniques for digitized video-images and photographs: classical Wiener filtering, constrained maximum entropy, and some variants of constrained minimum total variation. Basic concepts and experimental results are discussed. Because all methods appeared to produce different results, a discussion is given of which method is the most suitable, depending on the image objects that are questioned, prior knowledge and type of blur and noise. Constrained minimum total variation methods produced the best results for test images with simulated noise and blur. In cases where images are the most substantial part of the evidence, constrained maximum entropy might be more suitable, because its theoretical basis predicts a restoration result that shows the most likely pixel values, given all the prior knowledge used during restoration.

  3. Comparative imaging study on monkeys with hemi-parkinsonism

    International Nuclear Information System (INIS)

    Wang Wei; Yu Xiaoping; Mao Jun; Liu Sheng; Wang Xiaoyi; Peng Guangchun; Wang Ruiwen

    2003-01-01

    Objective: To study the imaging appearance of experimental Parkinson's disease (PD) and to evaluate the different medical imaging exams on PD. Methods: CT, MRI, SPECT (dopamine transporter imaging and regional cerebral blood flow imaging, DAT imaging and rCBF imaging), and PET (glucose metabolism imaging) were performed on 8 monkeys before and after the infusion of MPTP into unilateral internal carotid artery to develop hemi-Parkinsonism models. Results: Hemi-Parkinsonism models were successfully induced on all 8 monkeys. On DAT imaging, the uptake values of the lesioned striatums decreased obviously after the MPTP treatment and were lower than that of the contralateral ones. The glucose metabolic rates of the lesioned striatums and thalamus in PD models were lower, compared to that of the healthy monkeys and that of the contralateral sides of themselves. Neither DAT nor glucose metabolism abnormalities was found on both the contralateral sides of the healthy and PD monkeys. On MRI images before MPTP treatment, only 4 of 8 PD models showed hypointense in bilateral globus pallidus. No abnormal MRI findings occurred in the first 2 months after injection of MPTP. At tile third month, hypointense appeared in globus pallidus of three monkeys. Enlarged hyposignal region in globus pallidus were found in three models. Of the above 6 monkeys, two appeared hypointense in putamina. Substantia nigra demonstrated no abnormalities before and after MPTP treatment. All rCBF and CT images were normal. Conclusion: The decreased density of DAT and decreased glucose metabolism on experimental PD can be showed early by DAT imaging and glucose metabolism imaging, MRI can show abnormal signal in the basal ganglia of PD but it is later than DAT and glucose metabolism imaging. CT and rCBF find no abnormality on PD

  4. New Image Qualities in Education: A Comparative Study

    Science.gov (United States)

    Çankaya, Ibrahim

    2018-01-01

    The aim of this study is to compare Turkish and European Union Countries Educations in terms of the new image qualities such as data like access to online education, digital access, foreign languages learnt per pupil, research & development investments, human resources employed in science and technology, the study opportunities offered to…

  5. Image based 3D city modeling : Comparative study

    Directory of Open Access Journals (Sweden)

    S. P. Singh

    2014-06-01

    Full Text Available 3D city model is a digital representation of the Earth’s surface and it’s related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing rapidly for various engineering and non-engineering applications. Generally four main image based approaches were used for virtual 3D city models generation. In first approach, researchers were used Sketch based modeling, second method is Procedural grammar based modeling, third approach is Close range photogrammetry based modeling and fourth approach is mainly based on Computer Vision techniques. SketchUp, CityEngine, Photomodeler and Agisoft Photoscan are the main softwares to represent these approaches respectively. These softwares have different approaches & methods suitable for image based 3D city modeling. Literature study shows that till date, there is no complete such type of comparative study available to create complete 3D city model by using images. This paper gives a comparative assessment of these four image based 3D modeling approaches. This comparative study is mainly based on data acquisition methods, data processing techniques and output 3D model products. For this research work, study area is the campus of civil engineering department, Indian Institute of Technology, Roorkee (India. This 3D campus acts as a prototype for city. This study also explains various governing parameters, factors and work experiences. This research work also gives a brief introduction, strengths and weakness of these four image based techniques. Some personal comment is also given as what can do or what can’t do from these softwares. At the last, this study shows; it concluded that, each and every software has some advantages and limitations. Choice of software depends on user requirements of 3D project. For normal visualization project, SketchUp software is a good option. For 3D documentation record, Photomodeler gives good

  6. A comparative study of image low level feature extraction algorithms

    Directory of Open Access Journals (Sweden)

    M.M. El-gayar

    2013-07-01

    Full Text Available Feature extraction and matching is at the base of many computer vision problems, such as object recognition or structure from motion. Current methods for assessing the performance of popular image matching algorithms are presented and rely on costly descriptors for detection and matching. Specifically, the method assesses the type of images under which each of the algorithms reviewed herein perform to its maximum or highest efficiency. The efficiency is measured in terms of the number of matches founds by the algorithm and the number of type I and type II errors encountered when the algorithm is tested against a specific pair of images. Current comparative studies asses the performance of the algorithms based on the results obtained in different criteria such as speed, sensitivity, occlusion, and others. This study addresses the limitations of the existing comparative tools and delivers a generalized criterion to determine beforehand the level of efficiency expected from a matching algorithm given the type of images evaluated. The algorithms and the respective images used within this work are divided into two groups: feature-based and texture-based. And from this broad classification only three of the most widely used algorithms are assessed: color histogram, FAST (Features from Accelerated Segment Test, SIFT (Scale Invariant Feature Transform, PCA-SIFT (Principal Component Analysis-SIFT, F-SIFT (fast-SIFT and SURF (speeded up robust features. The performance of the Fast-SIFT (F-SIFT feature detection methods are compared for scale changes, rotation, blur, illumination changes and affine transformations. All the experiments use repeatability measurement and the number of correct matches for the evaluation measurements. SIFT presents its stability in most situations although its slow. F-SIFT is the fastest one with good performance as the same as SURF, SIFT, PCA-SIFT show its advantages in rotation and illumination changes.

  7. a Comparative Case Study of Reflection Seismic Imaging Method

    Science.gov (United States)

    Alamooti, M.; Aydin, A.

    2017-12-01

    Seismic imaging is the most common means of gathering information about subsurface structural features. The accuracy of seismic images may be highly variable depending on the complexity of the subsurface and on how seismic data is processed. One of the crucial steps in this process, especially in layered sequences with complicated structure, is the time and/or depth migration of seismic data.The primary purpose of the migration is to increase the spatial resolution of seismic images by repositioning the recorded seismic signal back to its original point of reflection in time/space, which enhances information about complex structure. In this study, our objective is to process a seismic data set (courtesy of the University of South Carolina) to generate an image on which the Magruder fault near Allendale SC can be clearly distinguished and its attitude can be accurately depicted. The data was gathered by common mid-point method with 60 geophones equally spaced along an about 550 m long traverse over a nearly flat ground. The results obtained from the application of different migration algorithms (including finite-difference and Kirchhoff) are compared in time and depth domains to investigate the efficiency of each algorithm in reducing the processing time and improving the accuracy of seismic images in reflecting the correct position of the Magruder fault.

  8. Comparative study of low-energy neutral atom imaging techniques

    International Nuclear Information System (INIS)

    Funsten, H.O.; McComas, D.J.; Scime, E.E.

    1994-01-01

    Low-energy neutral atom (LENA) imaging promise to be a revolutionary tool for global imaging of space plasmas. The technical challenges of LENA detection include separating them from the intense ambient UV without losing information about their incident trajectories, quantifying their trajectories, and obtaining high-sensitivity measurements. Two techniques that have been proposed for this purpose are based on fundamentally different atomic interaction mechanisms between LENAs and a solid; LENA transmission through an ultra thin foil and LENA reflection from a solid surface. Both of these methods provide LENA ionization (for subsequent removal from the UV by electrostatic deflection) and secondary electron emission (for time-of-flight start pulse generation and/or coincidence). They present a comparative study of the transmission and reflection techniques based on differences in atomic interactions with solids and surfaces. Transmission methods are shown to be superior for secondary electron emission rather than reflection methods. Furthermore, transmission methods are shown to be a sufficient for LENA imaging at LENA energies of approximately 1 keV to greater than 30 keV. A hybrid instrument using reflection from a low work function surface for LENA ionization and transmission for secondary electron emission is optimal for imaging of LENAs with energies less than approximately 1 keV

  9. Comparative study of ultrasound imaging, computed tomography and magnetic resonance imaging in gynecology

    International Nuclear Information System (INIS)

    Ishii, Kenji; Kobayashi, Hisaaki; Hoshihara, Takayuki; Kobayashi, Mitsunao; Suda, Yoshio; Takenaka, Eiichi; Sasa, Hidenori.

    1989-01-01

    We studied 18 patients who were operated at the National Defense Medical College Hospital and confirmed by pathological diagnosis. We compared ultrasound imaging, computed tomography (CT) and magnetic resonance imaging (MRI) of the patients. MRI was useful to diagnose enlargement of the uterine cavity and a small amount of ascites and to understand orientation of the pelvic organs. Ultrasound imaging is the most useful examination to diagnose gynecological diseases. But when it is difficult to diagnose by ultrasound imaging alone, we should employ either CT or MRI, or preferably both. (author)

  10. Elastic models: a comparative study applied to retinal images.

    Science.gov (United States)

    Karali, E; Lambropoulou, S; Koutsouris, D

    2011-01-01

    In this work various methods of parametric elastic models are compared, namely the classical snake, the gradient vector field snake (GVF snake) and the topology-adaptive snake (t-snake), as well as the method of self-affine mapping system as an alternative to elastic models. We also give a brief overview of the methods used. The self-affine mapping system is implemented using an adapting scheme and minimum distance as optimization criterion, which is more suitable for weak edges detection. All methods are applied to glaucomatic retinal images with the purpose of segmenting the optical disk. The methods are compared in terms of segmentation accuracy and speed, as these are derived from cross-correlation coefficients between real and algorithm extracted contours and segmentation time, respectively. As a result, the method of self-affine mapping system presents adequate segmentation time and segmentation accuracy, and significant independence from initialization.

  11. Collagenous sprue cross-sectional imaging: a comparative blinded study.

    Science.gov (United States)

    Al-Bawardy, Badr; Sheedy, Shannon P; Herberts, Michelle B; Murray, Joseph A; Rubio-Tapia, Alberto; Rajan, Elizabeth; Bruining, David H; Hansel, Stephanie L; Barlow, John M; Fletcher, Joel G; Fidler, Jeff L

    2017-02-01

    Collagenous sprue (CS) is a rare enteropathy characterized by villous atrophy and a thickened subepithelial collagen band. The aim of this study is to describe the cross-sectional imaging findings of CS. A case-control, retrospective study with cases of all CS patients from January 2000 to 2015 was performed. Inclusion criteria were (1) Histopathologic diagnosis and (2) Imaging with computed tomography abdomen/pelvis (CT A/P), CT enterography (CTE), or magnetic resonance enterography within 6 months of small bowel (SB) biopsy. Control subjects were irritable bowel syndrome (IBS) patients who underwent CTE. Imaging studies were examined by two GI radiologists, blinded to patient data. 108 patients (54 CS; 54 IBS) were included. Mean age was 56.7 ± 16.5 years, and 68% were female (72% in CS group vs. 63% in IBS group; p = 0.3). CS patients were significantly older (67 ± 12 vs. 47 ± 15 year; p reversal (46% vs. 6%; p < 0.001), SB dilation (28% vs. 0%; p < 0.001), SB conformational change (28% vs. 6%; p = 0.002), SB wall thickening (13% vs. 2%; p = 0.03), and ulcerative jejunoileitis (4% vs. 0%; p = 0.01). Radiologists suspected malabsorption in 72% in the CS group and 2% in the IBS group (p < 0.001). Imaging findings suggestive of mucosal malabsorption are commonly demonstrated in CS.

  12. A comparative study on medical image segmentation methods

    Directory of Open Access Journals (Sweden)

    Praylin Selva Blessy SELVARAJ ASSLEY

    2014-03-01

    Full Text Available Image segmentation plays an important role in medical images. It has been a relevant research area in computer vision and image analysis. Many segmentation algorithms have been proposed for medical images. This paper makes a review on segmentation methods for medical images. In this survey, segmentation methods are divided into five categories: region based, boundary based, model based, hybrid based and atlas based. The five different categories with their principle ideas, advantages and disadvantages in segmenting different medical images are discussed.

  13. Maxillary sinusitis - a comparative study of different imaging diagnosis methods

    International Nuclear Information System (INIS)

    Hueb, Marcelo Miguel; Borges, Fabiano de Almeida; Pulcinelli, Emilte; Souza, Wandir Ferreira; Borges, Luiz Marcondes

    1999-01-01

    We conducted prospective study comparing different methods (plain X-rays, computed tomography and ultrasonography mode-A) for the initial diagnosis of maxillary sinusitis. Twenty patients (40 maxillary sinuses) with a clinical history suggestive of sinusitis included in this study. The results were classified as abnormal or normal, using computed tomography as gold standard. The sensitivity for ultrasonography and plain X-rays was 84.6% and 69.2%, respectively. The specificity of both methods was 92.6%. This study suggests that ultrasonography can be used as a good follow-up method for patients with maxillary. sinusitis. (author)

  14. Comparative study between rib imaging of DR dual energy subtraction technology and chest imaging

    International Nuclear Information System (INIS)

    Yu Jianming; Lei Ziqiao; Kong Xiangchuang

    2006-01-01

    Objective: To investigate the application value of DR dual energy subtraction technology in rib lesions. Methods: 200 patients were performed with chest DR dual energy subtraction, comparing the rib imaging between DR of thorax and chest imaging using ROC analysis. Results: Among the total of 200 patients, there are 50 cases of rib calcification, 7 cases of rib destruction, 22 cases of rib fracture. The calcification, destruction and fracture were displayed respectively by ribs below diaphragm and rib markings. The analytic parameter of rib imaging of DR dual energy subtraction Az is 0.9367, while that of rib imaging of chest Az is 0.6830. Conclusion: DR dual energy subtraction technology is superior to chest imaging in the displaying of rib lesion and ribs below diaphragm. (authors)

  15. Comparative cardiac imaging

    International Nuclear Information System (INIS)

    Brundage, B.H.

    1990-01-01

    This book is designed to compare all major cardiac imaging techniques. All major imaging techniques - including conventional angiography, digital angiography, echocardiography and Doppler imaging, conventional radioisotope techniques, computed tomography, and magnetic resonance imaging - are covered in this text as they apply to the major cardiovascular disorders. There is brief coverage of positron emission tomography and an extensive presentation of ultrafast computed tomography

  16. Image quality and stability of image-guided radiotherapy (IGRT) devices: A comparative study

    International Nuclear Information System (INIS)

    Stock, Markus; Pasler, Marlies; Birkfellner, Wolfgang; Homolka, Peter; Poetter, Richard; Georg, Dietmar

    2009-01-01

    Introduction: Our aim was to implement standards for quality assurance of IGRT devices used in our department and to compare their performances with that of a CT simulator. Materials and methods: We investigated image quality parameters for three devices over a period of 16 months. A multislice CT was used as a benchmark and results related to noise, spatial resolution, low contrast visibility (LCV) and uniformity were compared with a cone beam CT (CBCT) at a linac and simulator. Results: All devices performed well in terms of LCV and, in fact, exceeded vendor specifications. MTF was comparable between CT and linac CBCT. Integral nonuniformity was, on average, 0.002 for the CT and 0.006 for the linac CBCT. Uniformity, LCV and MTF varied depending on the protocols used for the linac CBCT. Contrast-to-noise ratio was an average of 51% higher for the CT than for the linac and simulator CBCT. No significant time trend was observed and tolerance limits were implemented. Discussion: Reasonable differences in image quality between CT and CBCT were observed. Further research and development are necessary to increase image quality of commercially available CBCT devices in order for them to serve the needs for adaptive and/or online planning.

  17. Image quality and stability of image-guided radiotherapy (IGRT) devices: A comparative study.

    Science.gov (United States)

    Stock, Markus; Pasler, Marlies; Birkfellner, Wolfgang; Homolka, Peter; Poetter, Richard; Georg, Dietmar

    2009-10-01

    Our aim was to implement standards for quality assurance of IGRT devices used in our department and to compare their performances with that of a CT simulator. We investigated image quality parameters for three devices over a period of 16months. A multislice CT was used as a benchmark and results related to noise, spatial resolution, low contrast visibility (LCV) and uniformity were compared with a cone beam CT (CBCT) at a linac and simulator. All devices performed well in terms of LCV and, in fact, exceeded vendor specifications. MTF was comparable between CT and linac CBCT. Integral nonuniformity was, on average, 0.002 for the CT and 0.006 for the linac CBCT. Uniformity, LCV and MTF varied depending on the protocols used for the linac CBCT. Contrast-to-noise ratio was an average of 51% higher for the CT than for the linac and simulator CBCT. No significant time trend was observed and tolerance limits were implemented. Reasonable differences in image quality between CT and CBCT were observed. Further research and development are necessary to increase image quality of commercially available CBCT devices in order for them to serve the needs for adaptive and/or online planning.

  18. Overlapping montage: a comparative study of mainstream film and moving-image installations

    OpenAIRE

    Ryan, Orla G.

    2005-01-01

    This dissertation develops a discussion on the need for a comparative approach to the study of film and moving- image installations. It addresses the lack of critical attention given to moving-image installations within film studies generally and academic teaching programmes in particular. The development of a comparative approach requires researching a number of interlinking and independent fields of study such as film studies, art history/criticism, photography, literary theory, critical th...

  19. What Images Reveal: a Comparative Study of Science Images between Australian and Taiwanese Junior High School Textbooks

    Science.gov (United States)

    Ge, Yun-Ping; Unsworth, Len; Wang, Kuo-Hua; Chang, Huey-Por

    2017-07-01

    From a social semiotic perspective, image designs in science textbooks are inevitably influenced by the sociocultural context in which the books are produced. The learning environments of Australia and Taiwan vary greatly. Drawing on social semiotics and cognitive science, this study compares classificational images in Australian and Taiwanese junior high school science textbooks. Classificational images are important kinds of images, which can represent taxonomic relations among objects as reported by Kress and van Leeuwen (Reading images: the grammar of visual design, 2006). An analysis of the images from sample chapters in Australian and Taiwanese high school science textbooks showed that the majority of the Taiwanese images are covert taxonomies, which represent hierarchical relations implicitly. In contrast, Australian classificational images included diversified designs, but particularly types with a tree structure which depicted overt taxonomies, explicitly representing hierarchical super-ordinate and subordinate relations. Many of the Taiwanese images are reminiscent of the specimen images in eighteenth century science texts representing "what truly is", while more Australian images emphasize structural objectivity. Moreover, Australian images support cognitive functions which facilitate reading comprehension. The relationships between image designs and learning environments are discussed and implications for textbook research and design are addressed.

  20. COMPARATIVE STUDY OF EDGE BASED LSB MATCHING STEGANOGRAPHY FOR COLOR IMAGES

    Directory of Open Access Journals (Sweden)

    A.J. Umbarkar

    2016-02-01

    Full Text Available Steganography is a very pivotal technique mainly used for covert transfer of information over a covert communication channel. This paper proposes a significant comparative study of the spatial LSB domain technique that focuses on sharper edges of the color as well as gray scale images for the purpose of data hiding and hides secret message first in sharper edge regions and then in smooth regions of the image. Message embedding depends on content of the image and message size. The experimental results illustrate that, for low embedding rate the method hides the message in sharp edges of cover image to get better stego image visualization quality. For high embedding rate, smooth regions and edges of the cover image are used for the purpose of data hiding. In this steganography method, color image and textured kind of image preserves better visual quality of stego image. The novelty of the comparative study is that, it helps to analyze the efficiency and performance of the method as it gives better results because it directly works on color images instead of converting to gray scale image.

  1. Comparative study of digital laser film and analog paper image recordings

    International Nuclear Information System (INIS)

    Lee, K.R.; Cox, G.G.; Templeton, A.W.; Preston, D.F.; Anderson, W.H.; Hensley, K.S.; Dwyer, S.J.

    1987-01-01

    The increase in the use of various imaging modalities demands higher quality and more efficacious analog image recordings. Laser electronic recordings with digital array prints of 4,000 x 5,000 x 12 bits obtained using laser-sensitive film or paper are being evaluated. Dry silver paper recordings are being improved and evaluated. High-resolution paper dot printers are being studied to determine their gray-scale capabilities. The authors evaluated the image quality, costs, clinical utilization, and acceptability of CT scans, MR images, digital subtraction angiograms, digital radiographs, and radionuclide scans recorded by seven different printers (three laser, three silver paper, and one dot) and compared the same features in conventional film recording. This exhibit outlines the technical developments and instrumentation of digital laser film and analog paper recorders and presents the results of the study

  2. Comparative study on the performance of textural image features for active contour segmentation.

    Science.gov (United States)

    Moraru, Luminita; Moldovanu, Simona

    2012-07-01

    We present a computerized method for the semi-automatic detection of contours in ultrasound images. The novelty of our study is the introduction of a fast and efficient image function relating to parametric active contour models. This new function is a combination of the gray-level information and first-order statistical features, called standard deviation parameters. In a comprehensive study, the developed algorithm and the efficiency of segmentation were first tested for synthetic images. Tests were also performed on breast and liver ultrasound images. The proposed method was compared with the watershed approach to show its efficiency. The performance of the segmentation was estimated using the area error rate. Using the standard deviation textural feature and a 5×5 kernel, our curve evolution was able to produce results close to the minimal area error rate (namely 8.88% for breast images and 10.82% for liver images). The image resolution was evaluated using the contrast-to-gradient method. The experiments showed promising segmentation results.

  3. Comparative study of protoporphyrin IX fluorescence image enhancement methods to improve an optical imaging system for oral cancer detection

    Science.gov (United States)

    Jiang, Ching-Fen; Wang, Chih-Yu; Chiang, Chun-Ping

    2011-07-01

    Optoelectronics techniques to induce protoporphyrin IX fluorescence with topically applied 5-aminolevulinic acid on the oral mucosa have been developed to noninvasively detect oral cancer. Fluorescence imaging enables wide-area screening for oral premalignancy, but the lack of an adequate fluorescence enhancement method restricts the clinical imaging application of these techniques. This study aimed to develop a reliable fluorescence enhancement method to improve PpIX fluorescence imaging systems for oral cancer detection. Three contrast features, red-green-blue reflectance difference, R/B ratio, and R/G ratio, were developed first based on the optical properties of the fluorescence images. A comparative study was then carried out with one negative control and four biopsy confirmed clinical cases to validate the optimal image processing method for the detection of the distribution of malignancy. The results showed the superiority of the R/G ratio in terms of yielding a better contrast between normal and neoplastic tissue, and this method was less prone to errors in detection. Quantitative comparison with the clinical diagnoses in the four neoplastic cases showed that the regions of premalignancy obtained using the proposed method accorded with the expert's determination, suggesting the potential clinical application of this method for the detection of oral cancer.

  4. A comparative study of metal artifacts from common metal orthodontic brackets in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kajan, Zahra Dalili; Alizadeh, Ahmad; Hemmaty, Yasmin Babael; Roushan, Zahra Atrkar; Khademi, Jalil

    2015-01-01

    This study was performed to compare the metal artifacts from common metal orthodontic brackets in magnetic resonance imaging. A dry mandible with 12 intact premolars was prepared, and was scanned ten times with various types of brackets: American, 3M, Dentaurum, and Masel orthodontic brackets were used, together with either stainless steel (SS) or nickel titanium (NiTi) wires. Subsequently, three different sequences of coronal and axial images were obtained: spin-echo T1-weighted images, fast spin-echo T2-weighted images, and fluid-attenuated inversion recovery images. In each sequence, the two sequential axial and coronal images with the largest signal-void area were selected. The largest diameters of the signal voids in the direction of the X-, Y-, and Z-axes were then measured twice. Finally, the mean linear values associated with different orthodontic brackets were analyzed using one-way analysis of variation, and the results were compared using the independent t-test to assess whether the use of SS or NiTi wires had a significant effect on the images. Statistically significant differences were only observed along the Z-axis among the four different brands of orthodontic brackets with SS wires. A statistically significant difference was observed along all axes among the brackets with NiTi wires. A statistically significant difference was found only along the Z-axis between nickel-free and nickel-containing brackets. With respect to all axes, the 3M bracket was associated with smaller signal-void areas. Overall, the 3M and Dentaurum brackets with NiTi wires induced smaller artifacts along all axes than those with SS wires

  5. A comparative study of metal artifacts from common metal orthodontic brackets in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kajan, Zahra Dalili; Alizadeh, Ahmad; Hemmaty, Yasmin Babael; Roushan, Zahra Atrkar; Khademi, Jalil [Guilan University of Medical Sciences, Rasht (Iran, Islamic Republic of)

    2015-09-15

    This study was performed to compare the metal artifacts from common metal orthodontic brackets in magnetic resonance imaging. A dry mandible with 12 intact premolars was prepared, and was scanned ten times with various types of brackets: American, 3M, Dentaurum, and Masel orthodontic brackets were used, together with either stainless steel (SS) or nickel titanium (NiTi) wires. Subsequently, three different sequences of coronal and axial images were obtained: spin-echo T1-weighted images, fast spin-echo T2-weighted images, and fluid-attenuated inversion recovery images. In each sequence, the two sequential axial and coronal images with the largest signal-void area were selected. The largest diameters of the signal voids in the direction of the X-, Y-, and Z-axes were then measured twice. Finally, the mean linear values associated with different orthodontic brackets were analyzed using one-way analysis of variation, and the results were compared using the independent t-test to assess whether the use of SS or NiTi wires had a significant effect on the images. Statistically significant differences were only observed along the Z-axis among the four different brands of orthodontic brackets with SS wires. A statistically significant difference was observed along all axes among the brackets with NiTi wires. A statistically significant difference was found only along the Z-axis between nickel-free and nickel-containing brackets. With respect to all axes, the 3M bracket was associated with smaller signal-void areas. Overall, the 3M and Dentaurum brackets with NiTi wires induced smaller artifacts along all axes than those with SS wires.

  6. A comparative study of metal artifacts from common metal orthodontic brackets in magnetic resonance imaging.

    Science.gov (United States)

    Dalili Kajan, Zahra; Khademi, Jalil; Alizadeh, Ahmad; Babaei Hemmaty, Yasamin; Atrkar Roushan, Zahra

    2015-09-01

    This study was performed to compare the metal artifacts from common metal orthodontic brackets in magnetic resonance imaging. A dry mandible with 12 intact premolars was prepared, and was scanned ten times with various types of brackets: American, 3M, Dentaurum, and Masel orthodontic brackets were used, together with either stainless steel (SS) or nickel titanium (NiTi) wires. Subsequently, three different sequences of coronal and axial images were obtained: spin-echo T1 -weighted images, fast spin-echo T2 -weighted images, and fluid-attenuated inversion recovery images. In each sequence, the two sequential axial and coronal images with the largest signal-void area were selected. The largest diameters of the signal voids in the direction of the X-, Y-, and Z-axes were then measured twice. Finally, the mean linear values associated with different orthodontic brackets were analyzed using one-way analysis of variation, and the results were compared using the independent t-test to assess whether the use of SS or NiTi wires had a significant effect on the images. Statistically significant differences were only observed along the Z-axis among the four different brands of orthodontic brackets with SS wires. A statistically significant difference was observed along all axes among the brackets with NiTi wires. A statistically significant difference was found only along the Z-axis between nickel-free and nickel-containing brackets. With respect to all axes, the 3M bracket was associated with smaller signal-void areas. Overall, the 3M and Dentaurum brackets with NiTi wires induced smaller artifacts along all axes than those with SS wires.

  7. A comparative study of 99Tcm-tetrofosmin and 99Tcm-MIBI myocardial imaging

    International Nuclear Information System (INIS)

    Zhao Kui; Chen Peng; Zhang Furong; Shen Wenhua

    2001-01-01

    normal coronary artery were included in the study. Conclusions: Myocardial perfusion imaging with 99 Tc m -tetrofosmin or 99 Tc m -MIBI gives diagnostic information comparable to each other in patients undergoing one-day exercise/rest protocol for assessment of coronary artery disease. One-day exercise/rest myocardial perfusion with 99 Tc m -tetrofosmin is clinically feasible in detecting coronary artery disease

  8. Comparative study of quantitative phase imaging techniques for refractometry of optical fibers

    Science.gov (United States)

    de Dorlodot, Bertrand; Bélanger, Erik; Bérubé, Jean-Philippe; Vallée, Réal; Marquet, Pierre

    2018-02-01

    The refractive index difference profile of optical fibers is the key design parameter because it determines, among other properties, the insertion losses and propagating modes. Therefore, an accurate refractive index profiling method is of paramount importance to their development and optimization. Quantitative phase imaging (QPI) is one of the available tools to retrieve structural characteristics of optical fibers, including the refractive index difference profile. Having the advantage of being non-destructive, several different QPI methods have been developed over the last decades. Here, we present a comparative study of three different available QPI techniques, namely the transport-of-intensity equation, quadriwave lateral shearing interferometry and digital holographic microscopy. To assess the accuracy and precision of those QPI techniques, quantitative phase images of the core of a well-characterized optical fiber have been retrieved for each of them and a robust image processing procedure has been applied in order to retrieve their refractive index difference profiles. As a result, even if the raw images for all the three QPI methods were suffering from different shortcomings, our robust automated image-processing pipeline successfully corrected these. After this treatment, all three QPI techniques yielded accurate, reliable and mutually consistent refractive index difference profiles in agreement with the accuracy and precision of the refracted near-field benchmark measurement.

  9. Evaluating and comparing imaging techniques: a review and classification of study designs

    International Nuclear Information System (INIS)

    Freedman, L.S.

    1987-01-01

    The design of studies to evaluate and compare imaging techniques are reviewed. Thirteen principles for the design of studies of diagnostic accuracy are given. Because of the 'independence principle' these studies are not able directly to evaluate the contribution of a technique to clinical management. For the latter, the 'clinical value' study design is recommended. A classification of study designs is proposed in parallel with the standard classification of clinical trials. Studies of diagnostic accuracy are analogous to Phase II, whereas studies evaluating the contribution to clinical management correspond to the Phase III category. Currently the majority of published studies employ the Phase II design. More emphasis on Phase III studies is required. (author)

  10. [The alcoholic's self-image: a comparative study between men and women].

    Science.gov (United States)

    Aubry, C; Gay, M-C; Romo, L; Joffre, S

    2004-01-01

    Self-image is a central problem in alcoholism. Most theories about the relationships between the self-image of alcoholics and their behaviour have been derived from -clinical observations rather than empirical research. Most observations have pointed out that alcoholics are prone to underevaluation of themselves and that low self-image is the basis of much of the problem drinker's behaviour. All the research on self-image has concluded that alcoholics have a lower self-image than non-alcoholics. Some empirical research has been conducted on the self-image of alcoholics; it has, however, been carried out only a few times, restricted to small samples, and concerned with a limited number of aspects of self-image. Moreover, most of these studies are not recent, and it seems that this area of research is not well covered. Even though the hypothesis of a bad self-image in alcoholics was validated by various older studies, the representation of alcoholism has since changed. Because of this evolution, the ways in which the disease has been viewed have changed. One can question to what extent changes in society can influence the self-image of alcoholics. This question seems all the more pertinent for alcoholic women, given the evolution of the female condition since the Seventies. The objectives of this study are to evaluate the self-image of alcoholics and non-alcoholics, and to compare the self-image of male and female alcoholics. Our hypotheses are that: 1) the self-image of an alcoholic is more negative than that of a non-alcoholic, and that: 2) female alcoholics have a more negative self-image than male alcoholics. Two groups of 30 subjects each were made up: a group of alcoholics recruited in an alcohol-dependency unit and a group of non-alcoholics recruited in a public place. The comparison of socio-demographic data between the alcoholic group and the control group does not show a significant difference except for age and level of schooling. The average age of the

  11. Comparative study on developmental stages of the clavicle by postmortem MRI and CT imaging

    DEFF Research Database (Denmark)

    Larsen, Sara Tangmose; Lynnerup, Niels; Jensen, K.E.

    2013-01-01

    Objectives: The developmental stages of the clavicles are important for forensic age estimation purposes in adolescents. This study compares the 4-stage system to evaluate the ossification of the medial end of the clavicle as visualized by magnetic resonance imaging (MRI) and computed tomography...... (CT). As several forensic institutes routinely perform CT scans, the large amount of available data may serve as reference sample for MRI in specific cases. Material and methods: This prospective study included an MRI and CT scan of 47 autopsy cases performed prior to medico-legal autopsy (age range...

  12. A comparative study on methods of improving SCR for ship detection in SAR image

    Science.gov (United States)

    Lang, Haitao; Shi, Hongji; Tao, Yunhong; Ma, Li

    2017-10-01

    Knowledge about ship positions plays a critical role in a wide range of maritime applications. To improve the performance of ship detector in SAR image, an effective strategy is improving the signal-to-clutter ratio (SCR) before conducting detection. In this paper, we present a comparative study on methods of improving SCR, including power-law scaling (PLS), max-mean and max-median filter (MMF1 and MMF2), method of wavelet transform (TWT), traditional SPAN detector, reflection symmetric metric (RSM), scattering mechanism metric (SMM). The ability of SCR improvement to SAR image and ship detection performance associated with cell- averaging CFAR (CA-CFAR) of different methods are evaluated on two real SAR data.

  13. A comparative study of deep learning models for medical image classification

    Science.gov (United States)

    Dutta, Suvajit; Manideep, B. C. S.; Rai, Shalva; Vijayarajan, V.

    2017-11-01

    Deep Learning(DL) techniques are conquering over the prevailing traditional approaches of neural network, when it comes to the huge amount of dataset, applications requiring complex functions demanding increase accuracy with lower time complexities. Neurosciences has already exploited DL techniques, thus portrayed itself as an inspirational source for researchers exploring the domain of Machine learning. DL enthusiasts cover the areas of vision, speech recognition, motion planning and NLP as well, moving back and forth among fields. This concerns with building models that can successfully solve variety of tasks requiring intelligence and distributed representation. The accessibility to faster CPUs, introduction of GPUs-performing complex vector and matrix computations, supported agile connectivity to network. Enhanced software infrastructures for distributed computing worked in strengthening the thought that made researchers suffice DL methodologies. The paper emphases on the following DL procedures to traditional approaches which are performed manually for classifying medical images. The medical images are used for the study Diabetic Retinopathy(DR) and computed tomography (CT) emphysema data. Both DR and CT data diagnosis is difficult task for normal image classification methods. The initial work was carried out with basic image processing along with K-means clustering for identification of image severity levels. After determining image severity levels ANN has been applied on the data to get the basic classification result, then it is compared with the result of DNNs (Deep Neural Networks), which performed efficiently because of its multiple hidden layer features basically which increases accuracy factors, but the problem of vanishing gradient in DNNs made to consider Convolution Neural Networks (CNNs) as well for better results. The CNNs are found to be providing better outcomes when compared to other learning models aimed at classification of images. CNNs are

  14. A comparative study of 2 computer-assisted methods of quantifying brightfield microscopy images.

    Science.gov (United States)

    Tse, George H; Marson, Lorna P

    2013-10-01

    Immunohistochemistry continues to be a powerful tool for the detection of antigens. There are several commercially available software packages that allow image analysis; however, these can be complex, require relatively high level of computer skills, and can be expensive. We compared 2 commonly available software packages, Adobe Photoshop CS6 and ImageJ, in their ability to quantify percentage positive area after picrosirius red (PSR) staining and 3,3'-diaminobenzidine (DAB) staining. On analysis of DAB-stained B cells in the mouse spleen, with a biotinylated primary rat anti-mouse-B220 antibody, there was no significant difference on converting images from brightfield microscopy to binary images to measure black and white pixels using ImageJ compared with measuring a range of brown pixels with Photoshop (Student t test, P=0.243, correlation r=0.985). When analyzing mouse kidney allografts stained with PSR, Photoshop achieved a greater interquartile range while maintaining a lower 10th percentile value compared with analysis with ImageJ. A lower 10% percentile reflects that Photoshop analysis is better at analyzing tissues with low levels of positive pixels; particularly relevant for control tissues or negative controls, whereas after ImageJ analysis the same images would result in spuriously high levels of positivity. Furthermore comparing the 2 methods by Bland-Altman plot revealed that these 2 methodologies did not agree when measuring images with a higher percentage of positive staining and correlation was poor (r=0.804). We conclude that for computer-assisted analysis of images of DAB-stained tissue there is no difference between using Photoshop or ImageJ. However, for analysis of color images where differentiation into a binary pattern is not easy, such as with PSR, Photoshop is superior at identifying higher levels of positivity while maintaining differentiation of low levels of positive staining.

  15. Simultaneous storage of medical images in the spatial and frequency domain: A comparative study

    Directory of Open Access Journals (Sweden)

    Acharya U Rajendra

    2004-06-01

    Full Text Available Abstract Background Digital watermarking is a technique of hiding specific identification data for copyright authentication. This technique is adapted here for interleaving patient information with medical images, to reduce storage and transmission overheads. Methods The patient information is encrypted before interleaving with images to ensure greater security. The bio-signals are compressed and subsequently interleaved with the image. This interleaving is carried out in the spatial domain and Frequency domain. The performance of interleaving in the spatial, Discrete Fourier Transform (DFT, Discrete Cosine Transform (DCT and Discrete Wavelet Transform (DWT coefficients is studied. Differential pulse code modulation (DPCM is employed for data compression as well as encryption and results are tabulated for a specific example. Results It can be seen from results, the process does not affect the picture quality. This is attributed to the fact that the change in LSB of a pixel changes its brightness by 1 part in 256. Spatial and DFT domain interleaving gave very less %NRMSE as compared to DCT and DWT domain. Conclusion The Results show that spatial domain the interleaving, the %NRMSE was less than 0.25% for 8-bit encoded pixel intensity. Among the frequency domain interleaving methods, DFT was found to be very efficient.

  16. A comparative study of MR imaging scores and MR perfusion imaging in pre-operative grading of intracranial gliomas

    International Nuclear Information System (INIS)

    Wu Honglin; Chen Junkun; Zhang Zongjun; Lu Guangming; Chen Ziqian; Wang Wei; Ji Xueman; Tang Xiaojun; Li Lin

    2005-01-01

    Objective: To compare the accuracy of MR imaging scores with MR perfusion imaging in pre-operative grading of intracranial gliomas. Methods: Thirty patients with intracranial gliomas (8 low-grade and 22 high-grade, according to WHO criteria) were examined with MR perfusion imaging pre-operatively. The lesions were evaluated by using an MR imaging score based on nine criteria. rCBV of the lesions were calculated by comparing the CBV of the lesion and that of contralateral normal white matter. The scores and ratios in high-grade and low-grade tumours were compared. Results: The MR imaging score of low grade (grades I and II) gliomas (0.67±0.29) were significantly lower than that of grades III (1.32 ± 0.47) (t=-3.48, P=0.003) and IV (1.56 ± 0.20) (t=-7.36, P=0.000) gliomas. There was no statistical difference when MR imaging scores of grades III and IV gliomas (t=-1.39, P=0.182) were compared. The maximum rCBV ratio of low grade (grades I and II) gliomas (2.38 ± 0.66 ) were significantly lower than that of grades III (5.81 ± 3.20) (t=-3.57, P=0.003) and IV (6.99 ± 2.47) (t=-5.09, P=0.001). There was no statistical difference when rCBV ratios of grades III and IV (t =-0.93, P=0.365) gliomas were compared. The accuracy of MR imaging scores in the noninvasive grading of untreated gliomas was all most the same as that of MR perfusion imaging (90.00% vs 89.29%). Conclusion: The MR imaging scores and MR perfusion imaging are two very useful tools in the evaluation of the histopathologic grade of cerebral gliomas. The overall accuracy in the noninvasive grading of gliomas may be imp roved if MR imaging scores and MR perfusion imaging are combined. (authors)

  17. Comparative in vivo mucoadhesion studies of thiomer formulations using magnetic resonance imaging and fluorescence detection.

    Science.gov (United States)

    Albrecht, K; Greindl, M; Kremser, C; Wolf, C; Debbage, P; Bernkop-Schnürch, A

    2006-09-28

    The aim of this study was to compare different oral delivery systems based on the thiolated polymer polycarbophil-cysteine (PCP-Cys) and to provide evidence for the validity of the hypothesis that unhydrated polymers provide better mucoadhesion in vivo. To achieve dry polymer application, a new, experimental dosage form named Eutex (made of Eudragit L100-55 and latex) capsule has been developed. Magnetic resonance imaging was used to localize the point of release of the thiolated polymer from the application forms via the positive magnetic resonance signal from a gadolinium complex (Gd-DTPA). In vivo mucoadhesion was determined by ascertaining the residence time of the fluorescence-tagged thiomer on intestinal mucosa after 3 h. Results showed that in comparison to conventional application forms the Eutex capsules led to 1.9-fold higher mucoadhesive properties of PCP-Cys when compared to application with a conventional enteric-coated capsule, and to 1.4-fold higher mucoadhesion when compared to administration with an enteric-coated tablet of the thiomer. The findings of this study should contribute to the understanding of mucoadhesion and mucoadhesion influencing parameters in vivo and should therefore be of considerable interest for the development of future mucoadhesive oral drug delivery dosage forms.

  18. Comparative study of image registration techniques for bladder video-endoscopy

    Science.gov (United States)

    Ben Hamadou, Achraf; Soussen, Charles; Blondel, Walter; Daul, Christian; Wolf, Didier

    2009-07-01

    Bladder cancer is widely spread in the world. Many adequate diagnosis techniques exist. Video-endoscopy remains the standard clinical procedure for visual exploration of the bladder internal surface. However, video-endoscopy presents the limit that the imaged area for each image is about nearly 1 cm2. And, lesions are, typically, spread over several images. The aim of this contribution is to assess the performance of two mosaicing algorithms leading to the construction of panoramic maps (one unique image) of bladder walls. The quantitative comparison study is performed on a set of real endoscopic exam data and on simulated data relative to bladder phantom.

  19. A comparative study of three-dimensional reconstructive images of temporomandibular joint using computed tomogram

    International Nuclear Information System (INIS)

    Lim, Suk Young; Koh, Kwang Joon

    1993-01-01

    The purpose of this study was to clarify the spatial relationship of temporomandibular joint and to an aid in the diagnosis of temporomandibular disorder. For this study, three-dimensional images of normal temporomandibular joint were reconstructed by computer image analysis system and three-dimensional reconstructive program integrated in computed tomography. The obtained results were as follows : 1. Two-dimensional computed tomograms had the better resolution than three dimensional computed tomograms in the evaluation of bone structure and the disk of TMJ. 2. Direct sagittal computed tomograms and coronal computed tomograms had the better resolution in the evaluation of the disk of TMJ. 3. The positional relationship of the disk could be visualized, but the configuration of the disk could not be clearly visualized on three-dimensional reconstructive CT images. 4. Three-dimensional reconstructive CT images had the smoother margin than three-dimensional images reconstructed by computer image analysis system, but the images of the latter had the better perspective. 5. Three-dimensional reconstructive images had the better spatial relationship of the TMJ articulation, and the joint space were more clearly visualized on dissection images.

  20. Somatostatin receptor scintigraphy and magnetic resonance imaging in recurrent medullary thyroid carcinoma: A comparative study

    International Nuclear Information System (INIS)

    Doerr, U.; Wuerstlin, S.; Frank-Raue, K.; Raue, F.; Hehrmann, R.; Iser, G.; Scholz, M.; Guhl, L.; Buhr, H.J.; Bihl, H.

    1993-01-01

    In a prospective study, 18 patients with recurrent medullary thyroid carcinoma (MTC) underwent magnetic resonance imaging (MRI) of the neck and mediastinum and somatostatin receptor scintigraphy (SRS) with 111 In-labeled pentetreotide. In nine patients with macroscopic MTC, 17 corresponding lesions were found on MRI and SRS; in addition, 13 suspicious lesions were seen on SRS only. Histological confirmation was available for 19 metastatic lesions, showing MRI to be true positive in 13 metastases, SRS in 18. In minimal residual disease (n=10), MRI and SRS were compared with the histological findings in three patients and with selective venous catheterization (SVC) in seven patients. Corresponding findings on MRI and SVC were seen in one of seven, whereas SRS and SVC showed concordant localization of tumor recurrence in five of seven. Histological examination demonstrated MTC tissue in one of three cases; MRI and SRS were false positive in one of three cases, while in the others the interpretation remained uncertain. In conclusion, SRS is a promising imaging modality for localization of MTC recurrence. MRI provides better spatial resolution and thus facilitates the planning of surgery for macroscopic metastases. In minimal residual disease, SRS turned out to be superior in detecting occult MTC recurrence, confirming SVC findings. (orig.)

  1. An experimental comparative study of radiography, ultrasonography and CT imaging in the IV catheter fragment

    International Nuclear Information System (INIS)

    Kweon, Dae Cheol

    2016-01-01

    The objective of this study was to detect the fragments generated during IV (intravenous) catheter injection of contrast medium and drug administration in a clinical setting and removal was performed by experimentally producing a phantom, and to compare the radiography, ultrasonography, and multi-detector computed tomography (MDCT) imaging and radiation dose. A 1 cm fragment of an 18 gage Teflon® IV catheter with saline was inserted into the IV control line. Radiography, CT, and ultrasonography were performed and radiography and CT dose were calculated. CT and ultrasonography showed an IV catheter fragment clinically and radiography showed no visible difference in the ability to provide a useful image of an IV catheter fragment modality (p >.05). Radiography of effective dose (0.2139 mSv·Gy-1·cm-2) form DAP DAP (0.93 μGy·m2 ), and dose length product (DLP) (201 mGy·cm) to effective dose was calculated as 0.483 mSv. IV catheter fragment were detected of radiography, ultrasonography and CT. These results can be obtained by menas of an excellent IV catheter fragment of detection capability CT. However, CT is followed by radiation exposure. IV catheter fragment confirming the position and information recommend an ultrasonography

  2. Comparative study of image quality and radiation dose between prospective and retrospective ECG gating technique in coronary artery imaging with 64-slice spiral CT

    International Nuclear Information System (INIS)

    Liu Jianxin; Liu Jian; Dou Yanbin; Wang Jichen; Sun Hongyue

    2009-01-01

    Objective: To compare the image quality and radiation dose between prospective ECG-trigering and retrospective ECG gating technique in coronary artery imaging. Methods: 33 patients suspected coronary artery disease were included in this study and divided into experimental group (prospective ECG-triggering coronary artery imaging, heart rate 0.05). The mean DLP of experimental group (234.4 mGy · cm) was DLP of control group (974.4 mGy · cm) 24.1%. The mean effective dose of prospective ECG gating coronary artery imaging was 3.2 mSv. Effective dose reduced 76.47 %. Conclusions: Prospective ECG gating coronary artery imaging can obtain the similar image quality compared with prospective ECG gating coronary artery imaging but the effective dose reduced 76.47 %. Prospective ECG gating coronary artery imaging has clinical value to peoples who are able to not accept high radiation dose and with low heart rate. (authors)

  3. Comparative study of 201Tl reinjection mycoardial imaging and late imaging after reinjection for detecting myocardial viability

    International Nuclear Information System (INIS)

    Lin Jinghui; Chai Xiaofeng; Zhu Mei

    1997-01-01

    PURPOSE: To compare 201 Tl reinjection imaging with late imaging in detecting myocardial viability. METHODS: 62 patients with myocardial infarction underwent 201 Tl exercise, 3∼5 hours redistribution, 16∼35 minutes and 12∼19 hours post 201 Tl reinjection mycoardial tomography imaging. After imaging, percutaneous transluminal coronary angioplasty (PTCA) were performed in 15 patients, and then exercise-redistribution myocardial imaging were repeated. RESULTS: 62 patients had 126 segments of irreversible defects on stress-redistribution imaging, 48 segments showed radioactive filling at 16∼35 minutes post-reinjection. The detecting rate of myocardial viability was 38.1% (48/126). 51 segments presented redistribution on 12∼19 hours late imaging, the detecting rate of myocardial viability was 40.5% (51/126). There were no significant difference in the detecting rate between them (x 2 0.16, P>0.05). But in combination of both methods, there were 62 segments refilling, thereby detecting rate was enhanced to 49.2% (62/126). In 15 patients who had PTCA, out of 17 segments were discovered to be viable before PTCA. After PTCA 12 segments had an improved perfusion of 201 Tl, the positive predictive accuracy was 70.6%. Out of 11 segments were discovered to be infarcted, 9 segments had non-improved 201 Tl perfusion after PTCA, the negative predictive accuracy was 81.8%. CONCLUSION: There were no significant difference in the detecting rate of myocardial viability between 2 '0 1 Tl reinjection and late imaging. In combination of both methods the detecting rate can be enhanced

  4. Assessing Leg length Discrepancy Using a Biplane Low Dose Imaging System. A Comparative Diagnostic Study

    DEFF Research Database (Denmark)

    Jensen, Janni; Mussmann, Bo Redder; Torfing, Trine

    study was to evaluate the diagnostic accuracy of leg length (LL) measurements performed on low dose pre-view images acquired using a new bi-planar imaging system. The administered radiation dose from the pre-view image is approximately 20,17μGycm2 vs. 2670μGycm2 when acquiring the diagnostic image.......84) for the tibial measurements and the mean difference for total LLD was 0.01cm (p=0.92) and 0.03cm (p=0.73). All ICC calculations were >.99 indicating excellent inter- and intra-rater reliability. Conclusion. The results strongly imply that LL measurements performed on pre-view images acquired with a new bi...

  5. Comparative study of the macroscopic finding, conventional tomographic imaging, and computed tomographic imaging in locating the mandibular canal

    International Nuclear Information System (INIS)

    Choi, Hang Moon; You, Dong Soo

    1995-01-01

    The purpose of this study was comparison of conventional tomography with reformatted computed tomography for dental implant in locating the mandibular canal. Five dogs were used and after conventional tomographs and fitted computed tomographs were taken, four dentist traced all films. Mandibles were sectioned with 2 mm slice thickness and the sections were then radiographed (contact radiography). Each radiograpic image was traced and linear measurements were made from mandibular canal to alveolar crest, buccal cortex, lingual cortex, and inferior border. The following results were obtained; 1. Reformatted computed tomographs were exacter than conventional tomography by alveolar crest to canal length of -0.6 mm difference between real values and radiographs 2. The average measurements of buccal cortex to mandibular canal width and lingual cortex to mandibular canal width of conventional tomographs were exacter than reformatted computed tomographs, but standard deviations were higher than reformatted computed tomographs. 3. Standard deviations of reformatted computed tomographs were lower than conventional tomographs at all comparing sites 4. At reformatted computed tomography 62.5% of the measurements performed were within ±1 mm of the true value, and at conventional tomography 24.1% were. 5. Mandibular canal invisibility was 0.8% at reformatted computed tomography and 9.2% at conventional tomography. Reformatted computed tomography has been shown to be more useful radiographic technique for assessment of the mandibular canal than conventional tomography.

  6. SU-E-J-248: Comparative Study of Two Image Registration for Image-Guided Radiation Therapy in Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Shang, K; Wang, J; Liu, D; Li, R; Cao, Y; Chi, Z [The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, CN, Shijiazhuang, Hebei (China)

    2014-06-01

    Purpose: Image-guided radiation therapy (IGRT) is one of the major treatment of esophageal cancer. Gray value registration and bone registration are two kinds of image registration, the purpose of this work is to compare which one is more suitable for esophageal cancer patients. Methods: Twenty three esophageal patients were treated by Elekta Synergy, CBCT images were acquired and automatically registered to planning kilovoltage CT scans according to gray value or bone registration. The setup errors were measured in the X, Y and Z axis, respectively. Two kinds of setup errors were analysed by matching T test statistical method. Results: Four hundred and five groups of CBCT images were available and the systematic and random setup errors (cm) in X, Y, Z directions were 0.35, 0.63, 0.29 and 0.31, 0.53, 0.21 with gray value registration, while 0.37, 0.64, 0.26 and 0.32, 0.55, 0.20 with bone registration, respectively. Compared with bone registration and gray value registration, the setup errors in X and Z axis have significant differences. In Y axis, both measurement comparison results of T value is 0.256 (P value > 0.05); In X axis, the T value is 5.287(P value < 0.05); In Z axis, the T value is −5.138 (P value < 0.05). Conclusion: Gray value registration is recommended in image-guided radiotherapy for esophageal cancer and the other thoracic tumors. Manual registration could be applied when it is necessary. Bone registration is more suitable for the head tumor and pelvic tumor department where composed of redundant interconnected and immobile bone tissue.

  7. A comparative study of automatic image segmentation algorithms for target tracking in MR-IGRT.

    Science.gov (United States)

    Feng, Yuan; Kawrakow, Iwan; Olsen, Jeff; Parikh, Parag J; Noel, Camille; Wooten, Omar; Du, Dongsu; Mutic, Sasa; Hu, Yanle

    2016-03-01

    On-board magnetic resonance (MR) image guidance during radiation therapy offers the potential for more accurate treatment delivery. To utilize the real-time image information, a crucial prerequisite is the ability to successfully segment and track regions of interest (ROI). The purpose of this work is to evaluate the performance of different segmentation algorithms using motion images (4 frames per second) acquired using a MR image-guided radiotherapy (MR-IGRT) system. Manual contours of the kidney, bladder, duodenum, and a liver tumor by an experienced radiation oncologist were used as the ground truth for performance evaluation. Besides the manual segmentation, images were automatically segmented using thresholding, fuzzy k-means (FKM), k-harmonic means (KHM), and reaction-diffusion level set evolution (RD-LSE) algorithms, as well as the tissue tracking algorithm provided by the ViewRay treatment planning and delivery system (VR-TPDS). The performance of the five algorithms was evaluated quantitatively by comparing with the manual segmentation using the Dice coefficient and target registration error (TRE) measured as the distance between the centroid of the manual ROI and the centroid of the automatically segmented ROI. All methods were able to successfully segment the bladder and the kidney, but only FKM, KHM, and VR-TPDS were able to segment the liver tumor and the duodenum. The performance of the thresholding, FKM, KHM, and RD-LSE algorithms degraded as the local image contrast decreased, whereas the performance of the VP-TPDS method was nearly independent of local image contrast due to the reference registration algorithm. For segmenting high-contrast images (i.e., kidney), the thresholding method provided the best speed (<1 ms) with a satisfying accuracy (Dice=0.95). When the image contrast was low, the VR-TPDS method had the best automatic contour. Results suggest an image quality determination procedure before segmentation and a combination of different

  8. A Comparative Study on Diagnostic Accuracy of Colour Coded Digital Images, Direct Digital Images and Conventional Radiographs for Periapical Lesions – An In Vitro Study

    Science.gov (United States)

    Mubeen; K.R., Vijayalakshmi; Bhuyan, Sanat Kumar; Panigrahi, Rajat G; Priyadarshini, Smita R; Misra, Satyaranjan; Singh, Chandravir

    2014-01-01

    Objectives: The identification and radiographic interpretation of periapical bone lesions is important for accurate diagnosis and treatment. The present study was undertaken to study the feasibility and diagnostic accuracy of colour coded digital radiographs in terms of presence and size of lesion and to compare the diagnostic accuracy of colour coded digital images with direct digital images and conventional radiographs for assessing periapical lesions. Materials and Methods: Sixty human dry cadaver hemimandibles were obtained and periapical lesions were created in first and second premolar teeth at the junction of cancellous and cortical bone using a micromotor handpiece and carbide burs of sizes 2, 4 and 6. After each successive use of round burs, a conventional, RVG and colour coded image was taken for each specimen. All the images were evaluated by three observers. The diagnostic accuracy for each bur and image mode was calculated statistically. Results: Our results showed good interobserver (kappa > 0.61) agreement for the different radiographic techniques and for the different bur sizes. Conventional Radiography outperformed Digital Radiography in diagnosing periapical lesions made with Size two bur. Both were equally diagnostic for lesions made with larger bur sizes. Colour coding method was least accurate among all the techniques. Conclusion: Conventional radiography traditionally forms the backbone in the diagnosis, treatment planning and follow-up of periapical lesions. Direct digital imaging is an efficient technique, in diagnostic sense. Colour coding of digital radiography was feasible but less accurate however, this imaging technique, like any other, needs to be studied continuously with the emphasis on safety of patients and diagnostic quality of images. PMID:25584318

  9. An observer study comparing spot imaging regions selected by radiologists and a computer for an automated stereo spot mammography technique

    International Nuclear Information System (INIS)

    Goodsitt, Mitchell M.; Chan, Heang-Ping; Lydick, Justin T.; Gandra, Chaitanya R.; Chen, Nelson G.; Helvie, Mark A.; Bailey, Janet E.; Roubidoux, Marilyn A.; Paramagul, Chintana; Blane, Caroline E.; Sahiner, Berkman; Petrick, Nicholas A.

    2004-01-01

    We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full-field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD) program, and acquisition of a stereo pair of images with automated collimation to the suspicious region. The latter stereo spot image is obtained within seconds of the original full-field mammogram, without releasing the compression paddle. The spot image is viewed on a stereo video display. A critical element of this technique is the automated detection of suspicious regions for spot imaging. We performed an observer study to compare the suspicious regions selected by radiologists with those selected by a CAD program developed at the University of Michigan. True regions of interest (TROIs) were separately determined by one of the radiologists who reviewed the original mammograms, biopsy images, and histology results. We compared the radiologist and computer-selected regions of interest (ROIs) to the TROIs. Both the radiologists and the computer were allowed to select up to 3 regions in each of 200 images (mixture of 100 CC and 100 MLO views). We computed overlap indices (the overlap index is defined as the ratio of the area of intersection to the area of interest) to quantify the agreement between the selected regions in each image. The averages of the largest overlap indices per image for the 5 radiologist-to-computer comparisons were directly related to the average number of regions per image traced by the radiologists (about 50% for 1 region/image, 84% for 2 regions/image and 96% for 3 regions/image). The average of the overlap indices with all of the TROIs was 73% for CAD and 76.8%+/-10.0% for the radiologists. This study indicates that the CAD determined ROIs could potentially be useful for a screening technique that includes stereo spot

  10. Magnetic resonance imaging of the kidneys: A comparative study with anatomical sections

    International Nuclear Information System (INIS)

    Zilch, H.G.; Posel, P.; Muenchen Univ.

    1986-01-01

    Specimens of human kidneys (n=24) were investigated using magnetic resonance imaging (MRI), and compared with the corresponding cross-sections that had been prepared later from the same kidneys. The tomographs reveal detailed informations of renal fine structure. In particular, parenchyma and sinus can be easily differentiated from vasculature. It is possible to visualize vessel arborisation, including the arcuate vessels of the renal cortex. The clinical significance of renal MR tomographs is discussed. (orig.) [de

  11. A comparative study of automatic image segmentation algorithms for target tracking in MR‐IGRT

    Science.gov (United States)

    Feng, Yuan; Kawrakow, Iwan; Olsen, Jeff; Parikh, Parag J.; Noel, Camille; Wooten, Omar; Du, Dongsu; Mutic, Sasa

    2016-01-01

    On‐board magnetic resonance (MR) image guidance during radiation therapy offers the potential for more accurate treatment delivery. To utilize the real‐time image information, a crucial prerequisite is the ability to successfully segment and track regions of interest (ROI). The purpose of this work is to evaluate the performance of different segmentation algorithms using motion images (4 frames per second) acquired using a MR image‐guided radiotherapy (MR‐IGRT) system. Manual contours of the kidney, bladder, duodenum, and a liver tumor by an experienced radiation oncologist were used as the ground truth for performance evaluation. Besides the manual segmentation, images were automatically segmented using thresholding, fuzzy k‐means (FKM), k‐harmonic means (KHM), and reaction‐diffusion level set evolution (RD‐LSE) algorithms, as well as the tissue tracking algorithm provided by the ViewRay treatment planning and delivery system (VR‐TPDS). The performance of the five algorithms was evaluated quantitatively by comparing with the manual segmentation using the Dice coefficient and target registration error (TRE) measured as the distance between the centroid of the manual ROI and the centroid of the automatically segmented ROI. All methods were able to successfully segment the bladder and the kidney, but only FKM, KHM, and VR‐TPDS were able to segment the liver tumor and the duodenum. The performance of the thresholding, FKM, KHM, and RD‐LSE algorithms degraded as the local image contrast decreased, whereas the performance of the VP‐TPDS method was nearly independent of local image contrast due to the reference registration algorithm. For segmenting high‐contrast images (i.e., kidney), the thresholding method provided the best speed (<1 ms) with a satisfying accuracy (Dice=0.95). When the image contrast was low, the VR‐TPDS method had the best automatic contour. Results suggest an image quality determination procedure before segmentation and

  12. Magnetic resonance imaging and ultrasonography in diagnosing arthritis of the hand joints: a comparative study

    International Nuclear Information System (INIS)

    Ciechomska, A.; Bachta, A.; Tlustochowicz, W.; Serafin-Krol, M.; Jakubowski, W.; Andrysiak, R.; Krolicki, L.

    2005-01-01

    Assessment of joint inflammation in clinical practice is based on physical examination. Imaging modalities which allow soft tissues to be visualized may be helpful in making the assessment impartial and to evaluate the severity of inflammation. The aim of the study was to compare magnetic resonance imaging (MRI) and ultrasonography (USG) findings in visualizing joint inflammation of the hand. The study comprised 113 patients with chronic arthritis, of whom 88 patients had rheumatoid arthritis (RA) and 25 arthritis of etiology unconnected with RA. MRI of the hand was performed in 98 patients and USG of the hand in 86 patients. Sixty-four patients underwent both USG and MRI. In the USG examinations a linear, high-frequency transducer of 5-9 MHz and a Color Doppler option (CD-USG) were used. MRI was performed with a 1.5 T unit in the SE sequences T1, T1 with fat saturation, and before and after Gd-DTPA injection. Assessed joints included the wrist joints, etacarpophalangeal joints, and proximal and distal interphalangeal joints (1921 joints in total). Tenosynovitis of the flexors and extensors was also evaluated. MRI showed inflammation in 277 joints (16.6%) of 66 patients. The mean number of inflamed joints found using MRI was 2.8 ± 2.9. US visualized synovitis in a larger number of joints (350, 23.9%) in 63 patients. The mean number of inflamed joints found by USG was 4.1 ± 4.0. Increased blood flow on CD-USG was seen in 202 joints (13.8%) of 72 patients. The difference between RA and non-RA patients as visible on MRI and USG were statistically significant. There were correlations in showing joint inflammation between MRI and USG (τ = 0.64; p < 0.00001) and between CD-USG and MRI (τ = 0.44; p < 0.00001) and concordance in showing flexor tendon sheath inflammation. MRI and USG both show inflammation of the joints. The concordance between the methods in showing joint inflammation depends upon analyzing the features of inflammation. Availability and the

  13. Evaluation of gastric carcinoma with CT three-dimensional imaging compared with conventional barium study

    International Nuclear Information System (INIS)

    Ju Shenghong; Chen Feng; Zheng Kai'er; Sun Jun

    2002-01-01

    Objective: To assess the role of three-dimensional (3D) CT imaging including CT virtual gastroscopy (CTVG), surface-shaded display (SSD), and Raysum Display in the evaluation of gastric carcinoma compared with upper gastrointestinal series (UGI). Methods: In 43 histologically proved gastric carcinoma patients (37 advanced gastric carcinomas and 6 early gastric carcinomas), the results of CTVG and 3D CT imaging were compared to that of UGI. Two observers blindly evaluated images with all four techniques in terms of image quality, artifacts, diagnostic confidence, and Borrmann classification. Sensitivities of lesion detection and classification based on Borrmann classification of CTVG and 3D CT were determined by comparing them to surgical and histological findings. Results: The lesion detection sensitivity of CTVG, SSD, Raysum, and UGI by two observers were 98%, 67%, 60% and 84%, and 98%, 70%, 70% and 88%, respectively. The Borrmann's classification sensitivity by two observers were 76%, 49%, 38% and 49%, and 78%, 51%, 35% and 43%, respectively. Overall image quality of CTVG, SSD, and Raysum was considered similar to that of UGI by both observers (P>0.05). There was no statistical significant difference for advanced lesion (with diagnostic confidence of 3 or above) in detection sensitivity between CTVG and UGI (χ 2 = 0.50 and 0.25, P>0.05), but the lesion detection sensitivity of SSD and Raysum display were lower than that of UGI (χ 2 4.17, 7.11 and 5.14, 4.17, P 2 = 4.90 and 4.92, P 2 = 2.25, P > 0.05). Excess fluid remained in the stomach and patient respiratory movement during breath holds were the reasons causing severe artifacts (6.1%) that influenced the diagnostic evaluation. Conclusion: The performance of CTVG was equivalent to UGI in the Borrmann's classification. CTVG has potential in the detection of early gastric carcinoma. The value of SSD and Raysum display was limited in the evaluation of gastric carcinoma when used alone clinically

  14. In vivo comparative study of hydroxyapatite labeled with different radioisotopes: evaluation of the scintigraphic images

    Energy Technology Data Exchange (ETDEWEB)

    Couto, Renata Martinussi; Barboza, Marycel Figols de; Souza, Adriano Aparecido de; Muramoto, Emiko; Mengatti, Jair; Araujo, Elaine Bortoleti de, E-mail: rmcouto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia

    2008-07-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disorder of joints that is characterized by the inflammation and proliferation of synovial tissues. Approximately 3% of the adult population in the world is affected by this disease which causes pain, joint immobility and disability. Adyo synovectomy (RSV) is a radiotherapeutic modality where a b--emitting radionuclide is administered locally by intra-articular injection on the form of a colloid or radiolabeled particulate. RSV is a well-accepted therapeutic procedure in inflammatory joint diseases and has been successfully employed for more than 50 years as a viable alternative to surgical and chemical synovectomy in the treatment of RA and other inflammatory arthropathies. There are several radionuclides available for this purpose such as {sup 177}Lu, {sup 90}Y, {sup 153}Sm, {sup 165}Dy, and {sup 166}Ho. Hydroxyapatite (HA) is one of the preferred particulates for this application because it is the major chemical constituent of skeletal bone and it is converted into Ca and PO4 ions in the body. In addition HA is completely eliminated over a period of six weeks. The aim of this work is to compare the in vivo stability of hydroxyapatite labeled with {sup 177}Lu, {sup 90}Y and {sup 153}Sm in order to determine the influence of the radionuclide on biological pattern. In biological studies, 100mL of labeled HAs suspended in normal saline were injected into normal knee joints of Wistar rats and the retention of the activity into the synovium was determined. Labeled particles were also injected by intravenous and intramuscular administration, to verify the biodistribution in the case of an eventual leakage of the products from the joint. Sequential scintigraphic images were acquired from 1 hour to 7 days p.i. after anesthetizing the animals with ketamine. Hydroxyapatite was radiolabeled by all radionuclides with high yield. {sup 177}Lu-HA, {sup 90}Y-HA and {sup 153}Sm-HA were retained in the joint for 7 days, showing

  15. In vivo comparative study of hydroxyapatite labeled with different radioisotopes: evaluation of the scintigraphic images

    International Nuclear Information System (INIS)

    Couto, Renata Martinussi; Barboza, Marycel Figols de; Souza, Adriano Aparecido de; Muramoto, Emiko; Mengatti, Jair; Araujo, Elaine Bortoleti de

    2008-01-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disorder of joints that is characterized by the inflammation and proliferation of synovial tissues. Approximately 3% of the adult population in the world is affected by this disease which causes pain, joint immobility and disability. Adyo synovectomy (RSV) is a radiotherapeutic modality where a b--emitting radionuclide is administered locally by intra-articular injection on the form of a colloid or radiolabeled particulate. RSV is a well-accepted therapeutic procedure in inflammatory joint diseases and has been successfully employed for more than 50 years as a viable alternative to surgical and chemical synovectomy in the treatment of RA and other inflammatory arthropathies. There are several radionuclides available for this purpose such as 177 Lu, 90 Y, 153 Sm, 165 Dy, and 166 Ho. Hydroxyapatite (HA) is one of the preferred particulates for this application because it is the major chemical constituent of skeletal bone and it is converted into Ca and PO4 ions in the body. In addition HA is completely eliminated over a period of six weeks. The aim of this work is to compare the in vivo stability of hydroxyapatite labeled with 177 Lu, 90 Y and 153 Sm in order to determine the influence of the radionuclide on biological pattern. In biological studies, 100mL of labeled HAs suspended in normal saline were injected into normal knee joints of Wistar rats and the retention of the activity into the synovium was determined. Labeled particles were also injected by intravenous and intramuscular administration, to verify the biodistribution in the case of an eventual leakage of the products from the joint. Sequential scintigraphic images were acquired from 1 hour to 7 days p.i. after anesthetizing the animals with ketamine. Hydroxyapatite was radiolabeled by all radionuclides with high yield. 177 Lu-HA, 90 Y-HA and 153 Sm-HA were retained in the joint for 7 days, showing stability and usefulness as tools in the RSV treatment

  16. Comparative study of clinicopathological states and imaging diagnosis in patients with fatty liver

    International Nuclear Information System (INIS)

    Ariga, Hisayuki; Arakawa, Yasuyuki; Miyamoto, Masatoshi

    1985-01-01

    The authors clarified the characteristics of the clinicopathological states of 74 patients with the fatty liver classified by the etiology, simultaneously evaluating clinically the usefulness of imaging diagnosis with ultrasound and CT by the comparison of pathohistological findings(the rate of fat occupation in the liver). It was confirmed that, although the outcome of ultrasonic diagnosis was inferior to that of CT in the diagnostic capacity, the so-called bright liver finding was obtained, provided that the accumulation of fat in the liver was over Grade III (40 - 60 %), and that clinical diagnosis for fatty liver was possible. With CT, on the other hand, there was negative correlation between the degree of fat accumulation in the liver vs. the liver CT level and the CT ratio of the liver/spleen. Particularly, the CT ratio of the liver/spleen in this disease was 0.80 ± 0.18, indicating a significantly lower level as compared with 1.13 ± 0.13 in the control (p < 0.001). It is therefore suggested that, in patients in whom accumulation of fat in the liver is comparatively a lower level of Grade II (20 - 40 %), diagnosis for fatty liver by CT may be possible at a considerably high probability. Since these imaging diagnostic methods have been highly evaluated as non-invasive and convenient screening means of the fatty liver, it is important to establish the diagnostic criteria for graphic quantification of the fatty liver. (author)

  17. Dual-energy compared to single-energy CT in pediatric imaging: a phantom study for DECT clinical guidance

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaowei; Servaes, Sabah; Darge, Kassa [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, The Perelman School of Medicine, Philadelphia, PA (United States); McCullough, William P. [University of Virginia Health System, Department of Radiology and Medical Imaging, Charlottesville, VA (United States); Mecca, Patricia [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2016-11-15

    Dual-energy CT technology is available on scanners from several vendors and offers significant advantages over classic single-energy CT technology in multiple clinical applications. Many studies have detailed dual-energy CT applications in adults and several have evaluated the relative radiation dose performance of dual-energy CT in adult imaging. However, little has been published on dual-energy CT imaging in the pediatric population, and the relative dose performance of dual-energy CT imaging in the pediatric population is not well described. When evaluating dual-energy CT technology for implementation into a routine clinical pediatric imaging practice, the radiation dose implications must be considered, and when comparing relative CT dose performance, image quality must also be evaluated. Therefore the purpose of this study is to develop dual-energy CT scan protocols based on our optimized single-energy scan protocols and compare the dose. We scanned the head, chest and abdomen regions of pediatric-size anthropomorphic phantoms with contrast inserts, using our optimized single-energy clinical imaging protocols on a Siemens Flash {sup registered} CT scanner. We then scanned the phantoms in dual-energy mode using matching image-quality reference settings. The effective CT dose index volume (CTDI{sub vol}) of the scans was used as a surrogate for relative dose in comparing the single- and dual-energy scans. Additionally, we evaluated image quality using visual assessment and contrast-to-noise ratio. Dual-energy CT scans of the head and abdomen were dose-neutral for all three phantoms. Dual-energy CT scans of the chest showed a relative dose increase over the single-energy scan for 1- and 5-year-old child-based age-equivalent phantoms, ranging 11-20%. Quantitative analysis of image quality showed no statistically significant difference in image quality between the single-energy and dual-energy scans. There was no clinically significant difference in image quality by

  18. Dual-energy compared to single-energy CT in pediatric imaging: a phantom study for DECT clinical guidance

    International Nuclear Information System (INIS)

    Zhu, Xiaowei; Servaes, Sabah; Darge, Kassa; McCullough, William P.; Mecca, Patricia

    2016-01-01

    Dual-energy CT technology is available on scanners from several vendors and offers significant advantages over classic single-energy CT technology in multiple clinical applications. Many studies have detailed dual-energy CT applications in adults and several have evaluated the relative radiation dose performance of dual-energy CT in adult imaging. However, little has been published on dual-energy CT imaging in the pediatric population, and the relative dose performance of dual-energy CT imaging in the pediatric population is not well described. When evaluating dual-energy CT technology for implementation into a routine clinical pediatric imaging practice, the radiation dose implications must be considered, and when comparing relative CT dose performance, image quality must also be evaluated. Therefore the purpose of this study is to develop dual-energy CT scan protocols based on our optimized single-energy scan protocols and compare the dose. We scanned the head, chest and abdomen regions of pediatric-size anthropomorphic phantoms with contrast inserts, using our optimized single-energy clinical imaging protocols on a Siemens Flash "r"e"g"i"s"t"e"r"e"d CT scanner. We then scanned the phantoms in dual-energy mode using matching image-quality reference settings. The effective CT dose index volume (CTDI_v_o_l) of the scans was used as a surrogate for relative dose in comparing the single- and dual-energy scans. Additionally, we evaluated image quality using visual assessment and contrast-to-noise ratio. Dual-energy CT scans of the head and abdomen were dose-neutral for all three phantoms. Dual-energy CT scans of the chest showed a relative dose increase over the single-energy scan for 1- and 5-year-old child-based age-equivalent phantoms, ranging 11-20%. Quantitative analysis of image quality showed no statistically significant difference in image quality between the single-energy and dual-energy scans. There was no clinically significant difference in image quality

  19. Blind deblurring of spiral CT images - comparative studies on edge-to-noise ratios

    International Nuclear Information System (INIS)

    Jiang Ming; Wan Ge; Skinner, Margaret W.; Rubinstein, Jay T.; Vannier, Michael W.

    2002-01-01

    A recently developed blind deblurring algorithm based on the edge-to-noise ratio has been applied to improve the quality of spiral CT images. Since the discrepancy measure used to quantify the edge and noise effects is not symmetric, there are several ways to formulate the edge-to-noise ratio. This article is to investigate the performance of those ratios with phantom and patient data. In the phantom study, it is shown that all the ratios share similar properties, validating the blind deblurring algorithm. The image fidelity improvement varies from 29% to 33% for different ratios, according to the root mean square error (RMSE) criterion; the optimal iteration number determined for each ratio varies from 25 to 35. Those ratios that are associated with most satisfactory performance are singled out for the image fidelity improvement of about 33% in the numerical simulation. After automatic blind deblurring with the selected ratios, the spatial resolution of CT is substantially refined in all the cases tested

  20. A comparative study between magnetic resonance imaging and histological findings of bone and soft tissue tumors

    International Nuclear Information System (INIS)

    Itoh, Koichi

    1995-01-01

    Diagnostic methodology for bone and soft tissue tumors has made great strides recently through the development of magnetic resonance imaging (MRI). Here we report a comparative assessment of the histological findings of bone and soft tissue tumors with MRI from 212 cases. The accuracy of a qualitative diagnosis was observed in a solitary bone cyst, enchondroma, giant cell tumor, chondrosarcoma, lipoma, hemangioma, neurinoma, and in a synovial cyst. However, the qualitative diagnosis of a malignant tumor was difficult because of the variety of the intratumoral histological changes. An enhanced-image using Gd-DTPA was useful for differentiation of the viable region in the internal area of a tumor, discrimination of the reactive zone of an edema or assessing vascularity, and for discrimination between a cyst and a solid tumor. Based on comparison with findings from the excised specimen, it was found that histological changes such as calcification, fibrosis, hemorrhaging and necrosis, and the presence or absence of a tumor capsule had been reflected accurately on MR images. However, infiltration of the tumor into the bone cortex and into the articular cartilage were found frequently to be false-positive on MRI. Although problems remained to be solved regarding the evaluation of the presence or absence of tumor infiltration into adjacent tissue, the depiction of periosteal reaction, and regarding differentiation from inflammatory disease, MRI was a very useful information source for operative planning because it could evaluate the relationship between the tumor and adjacent blood vessels or nerves, the effect of preoperative therapy, and effectively discriminate between benign and malignant tumors. (author)

  1. A Comparative Study of Improved Artificial Bee Colony Algorithms Applied to Multilevel Image Thresholding

    Directory of Open Access Journals (Sweden)

    Kanjana Charansiriphaisan

    2013-01-01

    Full Text Available Multilevel thresholding is a highly useful tool for the application of image segmentation. Otsu’s method, a common exhaustive search for finding optimal thresholds, involves a high computational cost. There has been a lot of recent research into various meta-heuristic searches in the area of optimization research. This paper analyses and discusses using a family of artificial bee colony algorithms, namely, the standard ABC, ABC/best/1, ABC/best/2, IABC/best/1, IABC/rand/1, and CABC, and some particle swarm optimization-based algorithms for searching multilevel thresholding. The strategy for an onlooker bee to select an employee bee was modified to serve our purposes. The metric measures, which are used to compare the algorithms, are the maximum number of function calls, successful rate, and successful performance. The ranking was performed by Friedman ranks. The experimental results showed that IABC/best/1 outperformed the other techniques when all of them were applied to multilevel image thresholding. Furthermore, the experiments confirmed that IABC/best/1 is a simple, general, and high performance algorithm.

  2. A Comparative Study of Landsat TM and SPOT HRG Images for Vegetation Classification in the Brazilian Amazon

    Science.gov (United States)

    Lu, Dengsheng; Batistella, Mateus; de Miranda, Evaristo E.; Moran, Emilio

    2009-01-01

    Complex forest structure and abundant tree species in the moist tropical regions often cause difficulties in classifying vegetation classes with remotely sensed data. This paper explores improvement in vegetation classification accuracies through a comparative study of different image combinations based on the integration of Landsat Thematic Mapper (TM) and SPOT High Resolution Geometric (HRG) instrument data, as well as the combination of spectral signatures and textures. A maximum likelihood classifier was used to classify the different image combinations into thematic maps. This research indicated that data fusion based on HRG multispectral and panchromatic data slightly improved vegetation classification accuracies: a 3.1 to 4.6 percent increase in the kappa coefficient compared with the classification results based on original HRG or TM multispectral images. A combination of HRG spectral signatures and two textural images improved the kappa coefficient by 6.3 percent compared with pure HRG multispectral images. The textural images based on entropy or second-moment texture measures with a window size of 9 pixels × 9 pixels played an important role in improving vegetation classification accuracy. Overall, optical remote-sensing data are still insufficient for accurate vegetation classifications in the Amazon basin. PMID:19789716

  3. A Comparative Study of Landsat TM and SPOT HRG Images for Vegetation Classification in the Brazilian Amazon.

    Science.gov (United States)

    Lu, Dengsheng; Batistella, Mateus; de Miranda, Evaristo E; Moran, Emilio

    2008-01-01

    Complex forest structure and abundant tree species in the moist tropical regions often cause difficulties in classifying vegetation classes with remotely sensed data. This paper explores improvement in vegetation classification accuracies through a comparative study of different image combinations based on the integration of Landsat Thematic Mapper (TM) and SPOT High Resolution Geometric (HRG) instrument data, as well as the combination of spectral signatures and textures. A maximum likelihood classifier was used to classify the different image combinations into thematic maps. This research indicated that data fusion based on HRG multispectral and panchromatic data slightly improved vegetation classification accuracies: a 3.1 to 4.6 percent increase in the kappa coefficient compared with the classification results based on original HRG or TM multispectral images. A combination of HRG spectral signatures and two textural images improved the kappa coefficient by 6.3 percent compared with pure HRG multispectral images. The textural images based on entropy or second-moment texture measures with a window size of 9 pixels × 9 pixels played an important role in improving vegetation classification accuracy. Overall, optical remote-sensing data are still insufficient for accurate vegetation classifications in the Amazon basin.

  4. Comparative Analysis and Modification of Imaging Techniques in the Parametric Studies of Control Systems

    Directory of Open Access Journals (Sweden)

    I. K. Romanova

    2017-01-01

    Full Text Available Bauman Moscow State Technical University, MoscowКалининградский государственный технический университет, КалининградThe article considers practical application aspects of various imaging techniques for parametric analysis of control systems. It is interpreted as a multivariate analysis aimed at studying the influence of external and internal parameters of the system on the quality of its functioning determined by direct and indirect quality criteria. The ultimate goal is to identify regions in the parameter space to provide an appropriate quality of the system. It is noted that visualization is a very important task-supporting aid for a designer to make decision. Stressed that the problem of parametric studies, in most cases, intersects with the major problem of inconsistency of separate partial criteria, i.e., the problem of multi-criteria optimization (MCO. Therefore, the aim of the article was to solve a joint task of visualization and multi-criteria optimization.The article considers traditional types of visualization in deterministic tasks (a 3-D graphics, plotting contour lines, gradient fields, Andrews curves, parallel coordinates, as well as methods used in statistics (graph matrices, etc.. Testing these methods as applied to the practical task of studying a double-circuit stabilization system allowed formulation of requirements for imaging techniques with multiple criteria.Provides a new perspective on using the traditional means to significantly enhance information capacity of imaging. A generic method of visualization is represented as a three-phase study agreed with the task of finding the compromise solutions. The first phase of the research involved identifying the monotony and contra-monotony domains. The second phase was aimed at identifying a region of compromise, or a weak Pareto optimum. The third phase involved the search for a consistent optimum (strong Pareto

  5. Diagnosis of alveolar and root fractures: an in vitro study comparing CBCT imaging with periapical radiographs

    Directory of Open Access Journals (Sweden)

    Solange KOBAYASHI-VELASCO

    Full Text Available Abstract Objective To compare periapical radiograph (PR and cone-beam computed tomography (CBCT in the diagnosis of alveolar and root fractures. Material and Methods Sixty incisor teeth (20 higid and 40 with root fracture from dogs were inserted in 60 anterior alveolar sockets (40 higid and 20 with alveolar fracture of 15 macerated canine maxillae. Each fractured socket had a root fractured tooth inserted in it. Afterwards, each maxilla was submitted to PR in two different vertical angulation incidences, and to CBCT imaging with a small field of view (FOV and high-definition protocol. Images were randomized and posteriorly analyzed by two oral and maxillofacial radiologists two times, with a two-week interval between observations. Results Sensitivity and specificity values were good for root fractures for PR and CBCT. For alveolar fractures, sensitivity ranged from 0.10 to 0.90 for PR and from 0.50 to 0.65 for CBCT. Specificity for alveolar fractures showed lower results than for root fractures for PR and CBCT. Areas under the ROC curve showed good results for both PR and CBCT for root fractures. However, results were fair for both PR and CBCT for alveolar fractures. When submitted to repeated measures ANOVA tests, there was a statistically significant difference between PR and CBCT for root fractures. Root fracture intraobserver agreement ranged from 0.90 to 0.93, and alveolar fracture intraobserver agreement ranged from 0.30 to 0.57. Interobserver agreement results were substantial for root fractures and poor/fair for alveolar fractures (0.11 for PR and 0.30 for CBCT. Conclusion Periapical radiograph with two different vertical angulations may be considered an accurate method to detect root fractures. However, PR showed poorer results than CBCT for the diagnosis of alveolar fractures. When no fractures are diagnosed in PR and the patient describes pain symptoms, the subsequent exam of choice is CBCT.

  6. MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

    International Nuclear Information System (INIS)

    Gaudino, Chiara; Csernus, Reka; Pham, Mirko; Bendszus, Martin; Rohde, Stefan; Cosgarea, Raluca; Kim, Ti-Sun; Heiland, Sabine; Beomonte Zobel, Bruno

    2011-01-01

    The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT). Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles. Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques. This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting. (orig.)

  7. MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

    Energy Technology Data Exchange (ETDEWEB)

    Gaudino, Chiara; Csernus, Reka; Pham, Mirko; Bendszus, Martin; Rohde, Stefan [University Hospital Heidelberg, Department of Neuroradiology, Heidelberg (Germany); Cosgarea, Raluca; Kim, Ti-Sun [University Hospital Heidelberg, Department of Periodontology, Heidelberg (Germany); Heiland, Sabine [University Hospital Heidelberg, Section of Experimental Radiology, Heidelberg (Germany); Beomonte Zobel, Bruno [University Campus Bio-Medico of Rome, Department of Radiology, Interdisciplinary Center for Biomedical Research, Rome (Italy)

    2011-12-15

    The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT). Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles. Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques. This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting. (orig.)

  8. Prospective comparative study of spiral computer tomography and magnetic resonance imaging for detection of hepatocellular carcinoma

    NARCIS (Netherlands)

    Stoker, J.; Romijn, M. G.; de Man, R. A.; Brouwer, J. T.; Weverling, G. J.; van Muiswinkel, J. M.; Zondervan, P. E.; Laméris, J. S.; Ijzermans, J. N. M.

    2002-01-01

    Background: Hepatocellular carcinoma (HCC) is often detected at a relatively late stage when tumour size prohibits curative surgery. Screening to detect HCC at an early stage is performed for patients at risk. Aim: The aim of this study was to compare prospectively the diagnostic accuracy and

  9. Should processed or raw image data be used in mammographic image quality analyses? A comparative study of three full-field digital mammography systems

    International Nuclear Information System (INIS)

    Borg, Mark; Badr, Ishmail; Royle, Gary

    2015-01-01

    The purpose of this study is to compare a number of measured image quality parameters using processed and unprocessed or raw images in two full-field direct digital units and one computed radiography mammography system. This study shows that the difference between raw and processed image data is system specific. The results have shown that there are no significant differences between raw and processed data in the mean threshold contrast values using the contrast-detail mammography phantom in all the systems investigated; however, these results cannot be generalised to all available systems. Notable differences were noted in contrast-to-noise ratios and in other tests including: response function, modulation transfer function, noise equivalent quanta, normalised noise power spectra and detective quantum efficiency as specified in IEC 62220-1-2. Consequently, the authors strongly recommend the use of raw data for all image quality analyses in digital mammography. (authors)

  10. Comparative study of image contrast in scanning electron microscope and helium ion microscope.

    Science.gov (United States)

    O'Connell, R; Chen, Y; Zhang, H; Zhou, Y; Fox, D; Maguire, P; Wang, J J; Rodenburg, C

    2017-12-01

    Images of Ga + -implanted amorphous silicon layers in a 110 n-type silicon substrate have been collected by a range of detectors in a scanning electron microscope and a helium ion microscope. The effects of the implantation dose and imaging parameters (beam energy, dwell time, etc.) on the image contrast were investigated. We demonstrate a similar relationship for both the helium ion microscope Everhart-Thornley and scanning electron microscope Inlens detectors between the contrast of the images and the Ga + density and imaging parameters. These results also show that dynamic charging effects have a significant impact on the quantification of the helium ion microscope and scanning electron microscope contrast. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  11. FLAIR imaging for multiple sclerosis: a comparative MR study at 1.5 and 3.0 Tesla

    International Nuclear Information System (INIS)

    Bachmann, Rainald; Reilmann, Ralf; Schwindt, Wolfram; Kugel, Harald; Heindel, Walter; Kraemer, Stefan

    2006-01-01

    The purpose of this study was (1) to identify the optimal TE for FLAIR-imaging at 3.0 T assessing three different echo times qualitatively and quantitatively and (2) to evaluate the diagnostic efficacy of high-field 3.0-T FLAIR imaging in comparison to conventional 1.5-T MRI in patients with multiple sclerosis (MS). Twenty-two patients with clinically definite MS underwent axial FLAIR imaging at 1.5 and 3.0 T. In 15 of these patients further FLAIR images with a TE of 100, 120 and 140 ms were acquired at 3.0 T. Imaging protocols were modified for 3.0 T using the increased SNR to acquire more and thinner slices while maintaining a comparable scan time. FLAIR images of either different TEs or different field strengths were ranked for each patient qualitatively by two observers. Signal intensity measurements were obtained in the gray and white matter, CSF and representative white matter lesions (WML). At 3.0 T, a TE of 100 and 120 ms proved superior in all qualitative categories when compared to 140 ms. In the quantitative assessment CNR of WML was highest for 120 ms (CNR: 19.8), intermediate for 100 ms (17.2) and lowest for 140 ms (15.3) (P<0.003). For lesion conspicuity and overall image quality, 3.0 T was judged superior to 1.5 T, whereas no difference was found for gray-white differentiation and image noise. With regard to artifacts, 3.0 T was inferior to 1.5 T. The CNR for WML was slightly lower at 3.0 T, but the difference was not significant (22.6 vs. 28.0, P=ns). (orig.)

  12. Comparative study of different approaches for multivariate image analysis in HPTLC fingerprinting of natural products such as plant resin.

    Science.gov (United States)

    Ristivojević, Petar; Trifković, Jelena; Vovk, Irena; Milojković-Opsenica, Dušanka

    2017-01-01

    Considering the introduction of phytochemical fingerprint analysis, as a method of screening the complex natural products for the presence of most bioactive compounds, use of chemometric classification methods, application of powerful scanning and image capturing and processing devices and algorithms, advancement in development of novel stationary phases as well as various separation modalities, high-performance thin-layer chromatography (HPTLC) fingerprinting is becoming attractive and fruitful field of separation science. Multivariate image analysis is crucial in the light of proper data acquisition. In a current study, different image processing procedures were studied and compared in detail on the example of HPTLC chromatograms of plant resins. In that sense, obtained variables such as gray intensities of pixels along the solvent front, peak area and mean values of peak were used as input data and compared to obtained best classification models. Important steps in image analysis, baseline removal, denoising, target peak alignment and normalization were pointed out. Numerical data set based on mean value of selected bands and intensities of pixels along the solvent front proved to be the most convenient for planar-chromatographic profiling, although required at least the basic knowledge on image processing methodology, and could be proposed for further investigation in HPLTC fingerprinting. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. A comparative study of 99Tcm (V)-DMSA imaging with histopathological examination in ovarian neoplasms

    International Nuclear Information System (INIS)

    Zhao Xinming; Wang Jianfang; Xu Fang; Yin Jie; Wei Lanxiu; Sun Li

    1999-01-01

    Objective: To assess the clinical value of 99 Tc m (V)-Dmsa imaging in detecting the ovarian and the pelvic cavity neoplasms. Methods: 99 Tc m (V)-DMSA imaging was performed on 24 patients with diagnosed ovarian neoplasms which were pathologically confirmed after operation. Results: 14 of the 15 patients with malignant ovarian tumors had positive 99 Tc m (V)-DMSA scintigraphy. However, 7 of 9 cases with benign ovarian tumors had negative 99 Tc m (V)-DMSA scintigraphy. The sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate, and accuracy of 99 Tc m (V)-DMSA imaging for detecting malignant ovarian tumors were 93.33%, 77.78%, 87.50%, 87.50%, 14.29%, 6.67% and 87.50%, respectively. Conclusions: 99 Tc m (V)-DMSA imaging is of important value in detecting malignant and benign ovarian and pelvic tumors

  14. Comparative study between fundus autofluorescence and red reflectance imaging of choroidal nevi using ultra-wide-field scanning laser ophthalmoscopy.

    Science.gov (United States)

    Zapata, Miguel Angel; Leila, Mahmoud; Teixidor, Teresa; Garcia-Arumi, Jose

    2015-06-01

    To explore the utility of fundus autofluorescence (FAF) and red reflectance (RR) imaging using ultra-wide-field scanning laser ophthalmoscope in choroidal nevi. Retrospective observational case study reviewing clinical data, color, FAF, and RR images of patients with choroidal nevi and comparing the findings. The ultra-wide-field scanning laser ophthalmoscope uses green laser 532 nm and red laser 633 nm that enabled FAF and RR imaging, respectively in separate channels. Superimposition of both images yielded a composite color image. The study included 46 eyes of 45 patients. Nevi were unilateral in 44 patients (98%). Forty-one nevi (89.1%) were located temporally between the macula and the equator. All nevi (100%) were deeply pigmented. The most frequent surface changes were lipofuscin pigments, zones of retinal pigment epithelium atrophy, and retinal pigment epithelium pigment clumps in 31 (67.3%), 18 (39.1%), and 8 eyes (17.3%), respectively. Color photographs were superior to FAF in detecting nevus boundaries and surface changes. Red reflectance correlated strongly with color images, although the nevus boundaries and surface changes were better delineated in RR mode. Red reflectance was superior to FAF in delineating the boundaries and surface changes of the nevus; clear visibility (3+) for RR versus no or poor visibility (0/1+) for FAF. Nevertheless, the areas of retinal pigment epithelium atrophy were better delineated in FAF mode; clear visibility (3+) for FAF versus poor visibility (1+) for FAF. Red reflectance imaging is more sensitive than conventional photography for follow-up of choroidal nevi. Fundus autofluorescence should be considered only as a complementary tool to RR imaging.

  15. Comparative study of adenosine and exercise 201Tl myocardial perfusion tomographic imaging for detection of coronary heart disease

    International Nuclear Information System (INIS)

    Wang Xiong

    1997-01-01

    To compare diagnostic accuracy of adenosine and exercise 201 Tl myocardial perfusion tomographic imaging for detection of coronary heart disease (CHD) in patients with a normal rest ECG and no history of myocardial infarction, 81 patients with CHD and 10 normal control subjects underwent adenosine myocardial perfusion imaging, exercise nuclide myocardial perfusion imaging was performed in 117 patients with CHD and 16 normal control subjects, two groups also had coronary arteriography. Both exercise and adenosine testing parameters were analysed. It is shown: 1) The sensitivity and specificity for detection of CHD were 79% vs 80% for adenosine group and 81% vs 81% for exercise myocardial perfusion imaging group respectively. There was no significant difference in comparison with two matched groups (χ 2 = 1.13, χ 2 = 0.18, χ 2 = 0.12, P>0.05). 2) Side effects induced by adenosine accounted for 89% of patients, all symptoms were mild and disappeared quickly after the termination of the study except in 2 cases withdrawal of infusion needed because of severe angina pectoris. Adenosine myocardial perfusion imaging is a safe and sensitive method for detection of CHD. The diagnostic value of adenosine test is similar to that of exercise myocardial perfusion imaging and particularly useful in evaluating patients unable to perform exercise test or achieve adequate level of exercise

  16. Wavelet-Based Visible and Infrared Image Fusion: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Angel D. Sappa

    2016-06-01

    Full Text Available This paper evaluates different wavelet-based cross-spectral image fusion strategies adopted to merge visible and infrared images. The objective is to find the best setup independently of the evaluation metric used to measure the performance. Quantitative performance results are obtained with state of the art approaches together with adaptations proposed in the current work. The options evaluated in the current work result from the combination of different setups in the wavelet image decomposition stage together with different fusion strategies for the final merging stage that generates the resulting representation. Most of the approaches evaluate results according to the application for which they are intended for. Sometimes a human observer is selected to judge the quality of the obtained results. In the current work, quantitative values are considered in order to find correlations between setups and performance of obtained results; these correlations can be used to define a criteria for selecting the best fusion strategy for a given pair of cross-spectral images. The whole procedure is evaluated with a large set of correctly registered visible and infrared image pairs, including both Near InfraRed (NIR and Long Wave InfraRed (LWIR.

  17. Comparative imaging study in ultrasound, MRI, CT, and DSA using a multimodality renal artery phantom

    Energy Technology Data Exchange (ETDEWEB)

    King, Deirdre M.; Fagan, Andrew J.; Moran, Carmel M.; Browne, Jacinta E. [Medical Ultrasound Physics and Technology Group, School of Physics, Dublin Institute of Technology, Dublin 8 (Ireland); Centre for Advanced Medical Imaging (CAMI), St James' s Hospital, Dublin 8 (Ireland); Department of Medical Physics, University of Edinburgh, Edinburgh EH16 4TJ (United Kingdom); Medical Ultrasound Physics and Technology Group, School of Physics, Dublin Institute of Technology, Dublin 8 (Ireland)

    2011-02-15

    Purpose: A range of anatomically realistic multimodality renal artery phantoms consisting of vessels with varying degrees of stenosis was developed and evaluated using four imaging techniques currently used to detect renal artery stenosis (RAS). The spatial resolution required to visualize vascular geometry and the velocity detection performance required to adequately characterize blood flow in patients suffering from RAS are currently ill-defined, with the result that no one imaging modality has emerged as a gold standard technique for screening for this disease. Methods: The phantoms, which contained a range of stenosis values (0%, 30%, 50%, 70%, and 85%), were designed for use with ultrasound, magnetic resonance imaging, x-ray computed tomography, and x-ray digital subtraction angiography. The construction materials used were optimized with respect to their ultrasonic speed of sound and attenuation coefficient, MR relaxometry (T{sub 1},T{sub 2}) properties, and Hounsfield number/x-ray attenuation coefficient, with a design capable of tolerating high-pressure pulsatile flow. Fiducial targets, incorporated into the phantoms to allow for registration of images among modalities, were chosen to minimize geometric distortions. Results: High quality distortion-free images of the phantoms with good contrast between vessel lumen, fiducial markers, and background tissue to visualize all stenoses were obtained with each modality. Quantitative assessments of the grade of stenosis revealed significant discrepancies between modalities, with each underestimating the stenosis severity for the higher-stenosed phantoms (70% and 85%) by up to 14%, with the greatest discrepancy attributable to DSA. Conclusions: The design and construction of a range of anatomically realistic renal artery phantoms containing varying degrees of stenosis is described. Images obtained using the main four diagnostic techniques used to detect RAS were free from artifacts and exhibited adequate contrast

  18. Comparative imaging study in ultrasound, MRI, CT, and DSA using a multimodality renal artery phantom

    International Nuclear Information System (INIS)

    King, Deirdre M.; Fagan, Andrew J.; Moran, Carmel M.; Browne, Jacinta E.

    2011-01-01

    Purpose: A range of anatomically realistic multimodality renal artery phantoms consisting of vessels with varying degrees of stenosis was developed and evaluated using four imaging techniques currently used to detect renal artery stenosis (RAS). The spatial resolution required to visualize vascular geometry and the velocity detection performance required to adequately characterize blood flow in patients suffering from RAS are currently ill-defined, with the result that no one imaging modality has emerged as a gold standard technique for screening for this disease. Methods: The phantoms, which contained a range of stenosis values (0%, 30%, 50%, 70%, and 85%), were designed for use with ultrasound, magnetic resonance imaging, x-ray computed tomography, and x-ray digital subtraction angiography. The construction materials used were optimized with respect to their ultrasonic speed of sound and attenuation coefficient, MR relaxometry (T 1 ,T 2 ) properties, and Hounsfield number/x-ray attenuation coefficient, with a design capable of tolerating high-pressure pulsatile flow. Fiducial targets, incorporated into the phantoms to allow for registration of images among modalities, were chosen to minimize geometric distortions. Results: High quality distortion-free images of the phantoms with good contrast between vessel lumen, fiducial markers, and background tissue to visualize all stenoses were obtained with each modality. Quantitative assessments of the grade of stenosis revealed significant discrepancies between modalities, with each underestimating the stenosis severity for the higher-stenosed phantoms (70% and 85%) by up to 14%, with the greatest discrepancy attributable to DSA. Conclusions: The design and construction of a range of anatomically realistic renal artery phantoms containing varying degrees of stenosis is described. Images obtained using the main four diagnostic techniques used to detect RAS were free from artifacts and exhibited adequate contrast to allow

  19. Functional magnetic resonance imaging study comparing rhythmic finger tapping in children and adults.

    Science.gov (United States)

    De Guio, François; Jacobson, Sandra W; Molteno, Christopher D; Jacobson, Joseph L; Meintjes, Ernesta M

    2012-02-01

    This study compared brain activation during unpaced rhythmic finger tapping in 12-year-old children with that of adults. Subjects pressed a button at a pace initially indicated by a metronome (12 consecutive tones), and then continued for 16 seconds of unpaced tapping to provide an assessment of their ability to maintain a steady rhythm. These analyses focused on the superior vermis of the cerebellum, which is known to play a key role in timing. Twelve adults and 12 children performed this rhythmic finger tapping task in a 3 T scanner. Whole-brain analyses were performed in Brain Voyager, with a random-effects analysis of variance using a general linear model. A dedicated cerebellar atlas was used to localize cerebellar activations. As in adults, unpaced rhythmic finger tapping in children demonstrated activations in the primary motor cortex, premotor cortex, and cerebellum. However, overall activation was different, in that adults demonstrated much more deactivation in response to the task, particularly in the occipital and frontal cortices. The other main differences involved the additional recruitment of motor and premotor areas in children compared with adults, and increased activity in the vermal region of the cerebellum. These findings suggest that the timing component of the unpaced rhythmic finger tapping task is less efficient and automatic in children, who need to recruit the superior vermis more intensively to maintain the rhythm, although they performed somewhat more poorly than adults. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Comparative study of deep learning methods for one-shot image classification (abstract)

    NARCIS (Netherlands)

    van den Bogaert, J.; Mohseni, H.; Khodier, M.; Stoyanov, Y.; Mocanu, D.C.; Menkovski, V.

    2017-01-01

    Training deep learning models for images classification requires large amount of labeled data to overcome the challenges of overfitting and underfitting. Usually, in many practical applications, these labeled data are not available. In an attempt to solve this problem, the one-shot learning paradigm

  1. Spatial Pyramids and Two-layer Stacking SVM classifiers for Image Categorization: A Comparative Study

    NARCIS (Netherlands)

    Abdullah, Azizi; Veltkamp, Remco C.; Wiering, Marco

    2009-01-01

    Recent research in image recognition has shown that combining multiple descriptors is a very useful way to improve classification performance. Furthermore, the use of spatial pyramids that compute descriptors at multiple spatial resolution levels generally increases the discriminative power of the

  2. Vascular channels in metacarpophalangeal joints : a comparative histologic and high-resolution imaging study

    NARCIS (Netherlands)

    Scharmga, A.; Keller, K.K.; Peters, M.; van Tubergen, A.; van den Bergh, J.P.W.; van Rietbergen, B.; Weijers, R.; Loeffen, D.; Hauge, E.M.; Geusens, P.P.M.M.

    2017-01-01

    We evaluated whether cortical interruptions classified as vascular channel (VC) on high-resolution peripheral quantitative computed tomography (HR-pQCT) could be confirmed by histology. We subsequently evaluated the image characteristics of histologically identified VCs on matched single and

  3. GPR Imaging for Deeply Buried Objects: A Comparative Study Based on FDTD Models and Field Experiments

    Science.gov (United States)

    Tilley, roger; Dowla, Farid; Nekoogar, Faranak; Sadjadpour, Hamid

    2012-01-01

    Conventional use of Ground Penetrating Radar (GPR) is hampered by variations in background environmental conditions, such as water content in soil, resulting in poor repeatability of results over long periods of time when the radar pulse characteristics are kept the same. Target objects types might include voids, tunnels, unexploded ordinance, etc. The long-term objective of this work is to develop methods that would extend the use of GPR under various environmental and soil conditions provided an optimal set of radar parameters (such as frequency, bandwidth, and sensor configuration) are adaptively employed based on the ground conditions. Towards that objective, developing Finite Difference Time Domain (FDTD) GPR models, verified by experimental results, would allow us to develop analytical and experimental techniques to control radar parameters to obtain consistent GPR images with changing ground conditions. Reported here is an attempt at developing 20 and 3D FDTD models of buried targets verified by two different radar systems capable of operating over different soil conditions. Experimental radar data employed were from a custom designed high-frequency (200 MHz) multi-static sensor platform capable of producing 3-D images, and longer wavelength (25 MHz) COTS radar (Pulse EKKO 100) capable of producing 2-D images. Our results indicate different types of radar can produce consistent images.

  4. Comparative studies of imaging procedures: What is the contribution of CT?

    International Nuclear Information System (INIS)

    Witte, G.; Buecheler, E.

    1990-01-01

    Within the field of diagnostic imaging, CT and MR are competing procedures, each of which has particular advantages in specific diagnostic situations. Knowledge of these advantages is helpful in deciding upon a diagnostic procedure. We evaluate the indications for CT according to area of examination. (orig.) [de

  5. Comparative study of fat-suppression techniques for hip arthroplasty MR imaging.

    Science.gov (United States)

    Molière, Sébastien; Dillenseger, Jean-Philippe; Ehlinger, Matthieu; Kremer, Stéphane; Bierry, Guillaume

    2017-09-01

    The goal of this study was to evaluate different fat-suppressed fluid-sensitive sequences in association with different metal artifacts reduction techniques (MARS) to determine which combination allows better fat suppression around metallic hip implants. An experimental study using an MRI fat-water phantom quantitatively evaluated contrast shift induced by metallic hip implant for different fat-suppression techniques and MARS. Then a clinical study with patients addressed to MRI unit for painful hip prosthesis compared these techniques in terms of fat suppression quality and diagnosis confidence. Among sequences without MARS, both T2 Dixon and short tau inversion recuperation (STIR) had significantly lower contrast shift (p < 0.05), Dixon offering the best fat suppression. Adding MARS (view-angle tilting or slice-encoding for metal artifact correction (SEMAC)) to STIR gave better results than Dixon alone, and also better than SPAIR and fat saturation with MARS (p < 0.05). There were no statistically significant differences between STIR with view-angle tilting and STIR with SEMAC in terms of fat suppression quality. STIR sequence is the preferred fluid-sensitive MR sequence in patients with metal implant. In combination with MARS (view-angle tilting or SEMAC), STIR appears to be the best option for high-quality fat suppression.

  6. Comparative study of fat-suppression techniques for hip arthroplasty MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Moliere, Sebastien [University Hospital of Strasbourg, Imaging Department, Strasbourg (France); Dillenseger, Jean-Philippe; Kremer, Stephane; Bierry, Guillaume [University Hospital of Strasbourg, Imaging Department, Strasbourg (France); ICube UMR 7357, University of Strasbourg, Strasbourg (France); Ehlinger, Matthieu [ICube UMR 7357, University of Strasbourg, Strasbourg (France); University Hospital of Strasbourg, Orthopaedic Department, Strasbourg (France)

    2017-09-15

    The goal of this study was to evaluate different fat-suppressed fluid-sensitive sequences in association with different metal artifacts reduction techniques (MARS) to determine which combination allows better fat suppression around metallic hip implants. An experimental study using an MRI fat-water phantom quantitatively evaluated contrast shift induced by metallic hip implant for different fat-suppression techniques and MARS. Then a clinical study with patients addressed to MRI unit for painful hip prosthesis compared these techniques in terms of fat suppression quality and diagnosis confidence. Among sequences without MARS, both T2 Dixon and short tau inversion recuperation (STIR) had significantly lower contrast shift (p < 0.05), Dixon offering the best fat suppression. Adding MARS (view-angle tilting or slice-encoding for metal artifact correction (SEMAC)) to STIR gave better results than Dixon alone, and also better than SPAIR and fat saturation with MARS (p < 0.05). There were no statistically significant differences between STIR with view-angle tilting and STIR with SEMAC in terms of fat suppression quality. STIR sequence is the preferred fluid-sensitive MR sequence in patients with metal implant. In combination with MARS (view-angle tilting or SEMAC), STIR appears to be the best option for high-quality fat suppression. (orig.)

  7. Comparative study of fat-suppression techniques for hip arthroplasty MR imaging

    International Nuclear Information System (INIS)

    Moliere, Sebastien; Dillenseger, Jean-Philippe; Kremer, Stephane; Bierry, Guillaume; Ehlinger, Matthieu

    2017-01-01

    The goal of this study was to evaluate different fat-suppressed fluid-sensitive sequences in association with different metal artifacts reduction techniques (MARS) to determine which combination allows better fat suppression around metallic hip implants. An experimental study using an MRI fat-water phantom quantitatively evaluated contrast shift induced by metallic hip implant for different fat-suppression techniques and MARS. Then a clinical study with patients addressed to MRI unit for painful hip prosthesis compared these techniques in terms of fat suppression quality and diagnosis confidence. Among sequences without MARS, both T2 Dixon and short tau inversion recuperation (STIR) had significantly lower contrast shift (p < 0.05), Dixon offering the best fat suppression. Adding MARS (view-angle tilting or slice-encoding for metal artifact correction (SEMAC)) to STIR gave better results than Dixon alone, and also better than SPAIR and fat saturation with MARS (p < 0.05). There were no statistically significant differences between STIR with view-angle tilting and STIR with SEMAC in terms of fat suppression quality. STIR sequence is the preferred fluid-sensitive MR sequence in patients with metal implant. In combination with MARS (view-angle tilting or SEMAC), STIR appears to be the best option for high-quality fat suppression. (orig.)

  8. Accuracy of reading liquid based cytology slides using the ThinPrep Imager compared with conventional cytology: prospective study

    Science.gov (United States)

    d'Assuncao, Jefferson; Irwig, Les; Macaskill, Petra; Chan, Siew F; Richards, Adele; Farnsworth, Annabelle

    2007-01-01

    Objective To compare the accuracy of liquid based cytology using the computerised ThinPrep Imager with that of manually read conventional cytology. Design Prospective study. Setting Pathology laboratory in Sydney, Australia. Participants 55 164 split sample pairs (liquid based sample collected after conventional sample from one collection) from consecutive samples of women choosing both types of cytology and whose specimens were examined between August 2004 and June 2005. Main outcome measures Primary outcome was accuracy of slides for detecting squamous lesions. Secondary outcomes were rate of unsatisfactory slides, distribution of squamous cytological classifications, and accuracy of detecting glandular lesions. Results Fewer unsatisfactory slides were found for imager read cytology than for conventional cytology (1.8% v 3.1%; Pcytology (7.4% v 6.0% overall and 2.8% v 2.2% for cervical intraepithelial neoplasia of grade 1 or higher). Among 550 patients in whom imager read cytology was cervical intraepithelial neoplasia grade 1 or higher and conventional cytology was less severe than grade 1, 133 of 380 biopsy samples taken were high grade histology. Among 294 patients in whom imager read cytology was less severe than cervical intraepithelial neoplasia grade 1 and conventional cytology was grade 1 or higher, 62 of 210 biopsy samples taken were high grade histology. Imager read cytology therefore detected 71 more cases of high grade histology than did conventional cytology, resulting from 170 more biopsies. Similar results were found when one pathologist reread the slides, masked to cytology results. Conclusion The ThinPrep Imager detects 1.29 more cases of histological high grade squamous disease per 1000 women screened than conventional cytology, with cervical intraepithelial neoplasia grade 1 as the threshold for referral to colposcopy. More imager read slides than conventional slides were satisfactory for examination and more contained low grade cytological

  9. A comparative study of postmortem MR imaging and pathological examination of human brain specimens

    International Nuclear Information System (INIS)

    Shiga, Tohru

    1998-01-01

    This study was designed to assess the value of MRI of the postmortem brain specimens by comparing MRI findings with neuropathological findings. Postmortem MRI was performed in 17 consecutive formalin-fixed whole brains comprising 3 with primary CNS neoplasm, 1 with metastatic brain tumor, 6 with cerebral vascular disease (CVD), 1 with degenerative disease, 1 with spongy state in thalamus, and 5 with no abnormality. Postmortem T2WI detected all neuropathological abnormalities but sparsely distributed tumor cells without edema. In one case of CNS neoplasm, the tumor lesions with little necrosis or edema showed isointensity to brain tissue, while others with large amounts of necrosis and edema showed high signal intensity on T2WI. In the cases of CVD, the major signal changes on T2WI were due to edema, necrosis, and damage of the organization as observed on neuropathological studies. There was one case in which both MRI and neuropathological examination showed an abnormality, which was pathologically unexplainable. In two cases, findings of postmortem MRI were more apparent than those of macroscopic examination. Postmortem MRI appeared different from premortem MRI in one of the rest three cases whereas the postmortem MRI correlated well with neuropathological findings. Progression of the disease immediately before death may have caused this difference. In conclusion, the correlations between MRI and neuropathological findings facilitate understanding the mechanisms responsible for MRI abnormalities. An increase in free water in edema, necrosis, and damage in brain tissue can explain an increased signal intensity on T2WI. Postmortem MRI may contribute to the effective pathological examination by pointing out subtle abnormalities before brain cutting. (author)

  10. Comparative study of imaging at 3.0 T versus 1.5 T of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Scott [University of California, San Francisco, Department of Radiology, San Francisco, CA (United States); University of Miami Miller School of Medicine, Miami, FL (United States); Steinbach, Lynne; Zhao, Jian; Link, Thomas M. [University of California, Department of Radiology, San Francisco, CA (United States); Stehling, Christoph [University of California, Department of Radiology, San Francisco, CA (United States); University of Muenster, Department of Radiology, Muenster (Germany); Ma, C.B. [University of California San Francisco, Department of Orthopedic Surgery, San Francisco, CA (United States)

    2009-08-15

    The objectives of the study were to compare MR imaging at 1.5 and 3.0 T in the same patients concerning image quality and visualization of cartilage pathology and to assess diagnostic performance using arthroscopy as a standard of reference. Twenty-six patients were identified retrospectively as having comparative 1.5 and 3.0 T MR studies of the knee within an average of 102 days. Standard protocols included T1-weighted and fat-saturated intermediate-weighted fast spin-echo sequences in three planes; sequence parameters had been adjusted to account for differences in relaxation at 3.0 T. Arthroscopy was performed in 19 patients. Four radiologists reviewed each study independently, scored image quality, and analyzed pathological findings. Sensitivities, specificities, and accuracies in diagnosing cartilage lesions were calculated in the 19 patients with arthroscopy, and differences between 1.5 and 3.0 T exams were compared using paired Student's t tests with a significance threshold of p<0.05. Each radiologist scored the 3.0 T studies higher than those obtained at 1.5 T in visualizing anatomical structures and abnormalities (p<0.05). Using arthroscopy as a standard of reference, diagnosis of cartilage abnormalities was improved at 3.0 T with higher sensitivity (75.7% versus 70.6%), accuracy (88.2% versus 86.4%), and correct grading of cartilage lesions (51.3% versus 42.9%). Diagnostic confidence scores were higher at 3.0 than 1.5 T (p<0.05) and signal-to-noise ratio at 3.0 T was approximately twofold higher than at 1.5 T. MRI at 3.0 T improved visualization of anatomical structures and improved diagnostic confidence compared to 1.5 T. This resulted in significantly better sensitivity and grading of cartilage lesions at the knee. (orig.)

  11. Comparative study of imaging at 3.0 T versus 1.5 T of the knee

    International Nuclear Information System (INIS)

    Wong, Scott; Steinbach, Lynne; Zhao, Jian; Link, Thomas M.; Stehling, Christoph; Ma, C.B.

    2009-01-01

    The objectives of the study were to compare MR imaging at 1.5 and 3.0 T in the same patients concerning image quality and visualization of cartilage pathology and to assess diagnostic performance using arthroscopy as a standard of reference. Twenty-six patients were identified retrospectively as having comparative 1.5 and 3.0 T MR studies of the knee within an average of 102 days. Standard protocols included T1-weighted and fat-saturated intermediate-weighted fast spin-echo sequences in three planes; sequence parameters had been adjusted to account for differences in relaxation at 3.0 T. Arthroscopy was performed in 19 patients. Four radiologists reviewed each study independently, scored image quality, and analyzed pathological findings. Sensitivities, specificities, and accuracies in diagnosing cartilage lesions were calculated in the 19 patients with arthroscopy, and differences between 1.5 and 3.0 T exams were compared using paired Student's t tests with a significance threshold of p<0.05. Each radiologist scored the 3.0 T studies higher than those obtained at 1.5 T in visualizing anatomical structures and abnormalities (p<0.05). Using arthroscopy as a standard of reference, diagnosis of cartilage abnormalities was improved at 3.0 T with higher sensitivity (75.7% versus 70.6%), accuracy (88.2% versus 86.4%), and correct grading of cartilage lesions (51.3% versus 42.9%). Diagnostic confidence scores were higher at 3.0 than 1.5 T (p<0.05) and signal-to-noise ratio at 3.0 T was approximately twofold higher than at 1.5 T. MRI at 3.0 T improved visualization of anatomical structures and improved diagnostic confidence compared to 1.5 T. This resulted in significantly better sensitivity and grading of cartilage lesions at the knee. (orig.)

  12. Comparative study between the Spin-echo and 3-D fast imaging techniques in the Knee evaluation with magnetic resonance

    International Nuclear Information System (INIS)

    Oleaga Zufiria, L.; Ibanez Zubiarrain, A.; Grande Icaran, J.; Vela Martin, A.C.; Cintora Leon, E.; Grau Garcia, M.; Grande Icaran, D.

    1993-01-01

    We have carried out a retrospective analysis of the results of magnetic resonance (MR) studies in 20 patients, comparing two different sequences. We compared a 2-D spin-echo (SE2D) sequence with a 3-D fast imaging with steady-state precession (FISP3D) sequence in the attempt to compare the reliability of each in the detection of knee injuries. Arthroscopy was employed as a control technique. Our study revealed no statistically significant difference between the two sequences, although the overall sensitivity for the detection of meniscal lesions was slightly greater with the FISP3D sequence; however, the reliability in the detection of ruptures of the posterior cruciate ligament is less with this sequence than with the SE2D sequence. Both sequences showed very low sensitivity in the detection of hyaline cartilage injuries. (Author) 14 refs

  13. A comparative study between the imaging system and the optical tracking system in proton therapy at CNAO

    CERN Document Server

    Desplanques, Maxime; Fontana, Giulia; Pella, Andrea; Riboldi, Marco; Fattori, Giovanni; Donno, Andrea; Baroni, Guido; Orecchia, Roberto

    2013-01-01

    The synergy between in-room imaging and optical tracking, in co-operation with highly accurate robotic patient handling represents a concept for patient-set-up which has been implemented at CNAO (Centro Nazionale di Adroterapia Oncologica). In-room imaging is based on a double oblique X-ray projection system; optical tracking consists of the detection of the position of spherical markers placed directly on the patient’s skin or on the immobilization devices. These markers are used as external fiducials during patient positioning and dose delivery. This study reports the results of a comparative analysis between in-room imaging and optical tracking data for patient positioning within the framework of high-precision particle therapy. Differences between the optical tracking system (OTS) and the imaging system (IS) were on average within the expected localization accuracy. On the first 633 fractions for head and neck (H&N) set-up procedures, the corrections applied by the IS, after patient positioning usin...

  14. A computer simulation study comparing lesion detection accuracy with digital mammography, breast tomosynthesis, and cone-beam CT breast imaging

    International Nuclear Information System (INIS)

    Gong Xing; Glick, Stephen J.; Liu, Bob; Vedula, Aruna A.; Thacker, Samta

    2006-01-01

    Although conventional mammography is currently the best modality to detect early breast cancer, it is limited in that the recorded image represents the superposition of a three-dimensional (3D) object onto a 2D plane. Recently, two promising approaches for 3D volumetric breast imaging have been proposed, breast tomosynthesis (BT) and CT breast imaging (CTBI). To investigate possible improvements in lesion detection accuracy with either breast tomosynthesis or CT breast imaging as compared to digital mammography (DM), a computer simulation study was conducted using simulated lesions embedded into a structured 3D breast model. The computer simulation realistically modeled x-ray transport through a breast model, as well as the signal and noise propagation through a CsI based flat-panel imager. Polyenergetic x-ray spectra of Mo/Mo 28 kVp for digital mammography, Mo/Rh 28 kVp for BT, and W/Ce 50 kVp for CTBI were modeled. For the CTBI simulation, the intensity of the x-ray spectra for each projection view was determined so as to provide a total average glandular dose of 4 mGy, which is approximately equivalent to that given in conventional two-view screening mammography. The same total dose was modeled for both the DM and BT simulations. Irregular lesions were simulated by using a stochastic growth algorithm providing lesions with an effective diameter of 5 mm. Breast tissue was simulated by generating an ensemble of backgrounds with a power law spectrum, with the composition of 50% fibroglandular and 50% adipose tissue. To evaluate lesion detection accuracy, a receiver operating characteristic (ROC) study was performed with five observers reading an ensemble of images for each case. The average area under the ROC curves (A z ) was 0.76 for DM, 0.93 for BT, and 0.94 for CTBI. Results indicated that for the same dose, a 5 mm lesion embedded in a structured breast phantom was detected by the two volumetric breast imaging systems, BT and CTBI, with statistically

  15. Studies on diagnostic value of CT images for hypopharyngeal cancer by comparing with sliced specimens

    International Nuclear Information System (INIS)

    Fujimura, Akiko

    1988-01-01

    The findings of preoperative CT were compared with extirpated specimens in 11 patients to evaluate the value of CT in diagnosing the extent of hypopharyngeal cancer. CT was capable of detecting tumor extent to the submucosal fibrofatty tissue, except for the case of tumor extent to the laryngeal ventricle that contains many mucous glands and is usually depicted as a dense shadow. When the margin of ossified cortex of the thyroid cartilage was irregular and surrounded by tumor shadow, or when the margin of the cricoid cartilage was irregular and accompanied by increased medullary concentration, the invasion of the tumor into these cartilages was histopathologically demonstrated. Tumor extension next to these ossified cartilages did not indicate histopathological invasion of the tumor whenever their margins were smooth and regular. The intrinsic laryngeal muscle and the inferior pharyngeal constrictor muscle were identified on CT. Tumor extent to these muscles was well correlated to histologically demonstrated tumor invasion. When vocal cord fixation was present, CT showed tumor extent either to the paralaryngeal space only or to the paralaryngeal space and thyroarytenoid muscle or posterior cricoarytenoid muscle. Extraluminal spread through the thyrohyoid membrane was depicted on CT as a distinctive shadow in the visceral space that surrounds the hypopharyngeal cavity. Computed tomography overestimated tumor invation into the submucosal layer, muscles, or laryngeal cartilages. (Namekawa, K.)

  16. Ultrasonography assessment of heel entheses in patients with spondyloarthritis: a comparative study with magnetic resonance imaging and conventional radiography.

    Science.gov (United States)

    Aguila Maldonado, Rodrigo; Ruta, Santiago; Valuntas, María Laura; García, Mercedes

    2017-08-01

    The aim of the present study was to determine the agreement between ultrasonography (US), magnetic resonance imaging (MRI), and conventional radiography (CR) in the detection of findings indicative of enthesopathy in spondyloarthritis (SpA) patients. A cross-sectional study was performed in 40 SpA patients. Heel entheses (Achilles tendon and plantar fascia) were bilaterally examined by US, MRI, and CR. The three imaging modalities were carried out by three independent operators blinded to the other imaging modality data. Soft tissue abnormalities indicative of enthesopathy as thickening, structural changes, and bursitis were assessed by both US and MRI, and cortical bone abnormalities indicative of enthesopathy as erosions and enthesophytes were assessed by the three imaging modalities. The unweighted kappa values between US and MRI were 0.80, 0.66, 0.69, 0.70, and 0.70 for thickening, structural changes, bursitis, enthesophytes, and bone erosions, respectively. With respect to the detection of enthesophytes, the unweighted kappa values between CR and both US and MRI were 0.78 and 0.76, respectively. At last, for the recognition of bone erosions, the unweighted kappa values between CR and both US and MRI were 0.38 and 0.45, respectively. Using MRI as standard reference method, US was more sensitive with respect to CR revealing bone erosions. The present study provides evidence about the high overall agreement between US and MRI for all abnormal comparable findings at entheseal level and between US, MRI, and CR for the detection of enthesophytes in SpA patients.

  17. Muscle lesion comparing of imaging procedures (sonography and MRT) -experimental and clinical study

    International Nuclear Information System (INIS)

    Mellerowicz, H.; Lubasch, A.; Dulce, M.; Wagner, S.; Paul, B.

    1993-01-01

    Muscle injuries in sports are more common now. Diagnosis and follow up of muscle injuries is nowadays achieved by sonography and MRT. In order to assess the two imagine procedures, a direct test for comparison of sonography and MRT was performed in an experimental study: A standardised disconnection of m. triceps surae in rats was either sutured and glued or not treated. Clinical studies were performed in 26 patients suffering from muscle trauma. Sonography was proved to be a reliable procedure especially in follow up control until full weight bearing and should be used first. Negative or doubtfull findings require further investigation by MRT. Especially contrast medium (Gd-DTPA) assisted examinations enables a long term follow up and may even show small (muscle strain) and deep lying injuries. (orig.) [de

  18. Comparative study of MR imaging and X-ray in Med-anemia

    International Nuclear Information System (INIS)

    Huang Zhongkui; Long Liling; Song Yingru

    2002-01-01

    Objective: To evaluate the diagnostic value of MRI and X-ray and to analyze MRI and X-ray characteristics in Med-anemia. Methods: MRI was performed in thoracic spine, lumbar spine, sacral spine, pelvis, and superior femurs in 15 patients with pathologically proved Med-anemia with T 1 WI and T 2 WI. Seven of them were examined on X-ray. Twenty volunteers were examined on MR as control group. The authors analyzed the manifestations of MRI in the Med-anemia, including abnormality of signal intensity of bone marrow, T 1 value, vertebral alteration of size and shaped, spinal cord compression due to epidural extramedullary haematopoiesis, and compared with the findings of bone on X-ray. Results: In the control group, bone marrow showed an inhomogeneous iso-signal intensity with band-shaped, triangular or motley high signal intensity in the middle or back part of the vertebra, neck of the femur on T 1 WI and a homogeneous iso-signal intensity on T 2 WI in the vertebra, pelvis, and superior femur. All cases with Med-anemia had low homogenous signal intensity in the bone marrow of the vertebra, pelvis and superior femur on T 1 WI but had no alterations on T 2 WI. The spinal cord was constricted resulting from protruding crushed vertebra with bullet-like shape in 4 cases. The soft tissue masses, confirmed as extramedullary haematopoiesis by operation, were demonstrated in 4 cases. Among 7 cases with X-ray examinations, 2 cases showed normal on X-ray but abnormal bone marrow on MRI, another 5 cases demonstrated bone alteration including osteoporosis, widening of striations, enlargement of ribs and vertebras. T 1 value showed (897.4 +- 75.43) ms in the Med- anemia group and (401.5 +- 28.1) ms in the control group with significant statistical difference (P 1 WI; (2) MRI is useful in demonstrating the space occupying lesion due to vertebral deformity, enlargement of ribs and extramedullary haematopoiesis

  19. Pathologic contrast enhancement of cerebral lesions: A comparative study using stereotactic CT, stereotactic MR imaging, and stereotactic biopsy

    International Nuclear Information System (INIS)

    Earnest, F. IV; Kelly, P.J.; Scheithauer, B.; Kall, B.; Cascino, T.L.; Ehman, R.L.; Forbes, G.

    1986-01-01

    The author compared the pattern and degree of Gd-DTPA dimeglumine contrast enhancement demonstrated on stereotactic MR images with that seen on stereotactic CT images obtained after conventional iodinated contrast agent enhancement and with histopathologic findings on sequential stereotactic brain biopsies. Stereotactic biopsies of the areas that enhanced on CT or MR imaging revealed tumor tissue with neovascularity. Tumor tissue with no or mild neovascularity did not enhance with contrast agent administration. Isolated tumor cells were frequently found beyond the margins of some primary brain neoplasms defined by contrast agent-enhanced MR imaging and CT. The histopathologic findings associated with pathologic contrast agent enhancement are presented

  20. MR imaging in recurrent pain after back surgery. A comparative study using standard and high doses of gadolinium contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Aakeson, P. [Univ. Hospital, Lund (Sweden). Dept. of Radiology; Annertz, M. [Univ. Hospital, Lund (Sweden). Dept. of Radiology; Kristoffersen, D.T. [Nycomed Imaging AS, Oslo (Norway); Jonsson, E. [Nycomed AB, Stockholm (Sweden); Holtaas, S. [Univ. Hospital, Lund (Sweden). Dept. of Radiology

    1996-11-01

    Purpose: To compare the diagnostic results following injection of (a) a high dose (0.3 mmol/kg b.w.) of gadodiamide injection and (b) the standard dose (0.1 mmol/kg b.w.) of Gd-DTPA, in patients with recurrent symptoms after surgery for lumbar disc herniation. Material and Methods: Twenty patients with recurrent or sustained symptoms after surgery for lumbar disc herniations were examined. MR imaging (0.3 T) was first performed before and after Gd-DTPA at 0.1 mmol/kg b.w., and then within one month (17 patients) or within 3 months (3 patients) before and after gadodiamide injection at 0.3 mmol/kg b.w. The examinations were first evaluated by 2 neuroradiologists blinded to dose but not to patient as the images were presented in pairs. Six months later the same investigators evaluated the examinations again, this time blinded to both dose and patient. Results: At the evaluation in pairs (with the investigators blinded to dose only) the high-dose examinations were considered the most informative (p=0.05). However, at the later evaluation (with the investigators blinded both to dose and patient) no significant difference between high and standard dose was found regarding diagnosis or diagnostic certainty. Conclusion: In this study the high-dose contrast enhancement of MR imaging at 0.3 T did not increase the diagnostic information for differentiating between scar and recurrent hernia. The high-dose images were considered more informative when evaluated in pairs, but gave no additional or different information when evaluated separately. The study also indicated that comparisons in pairs should be interpreted with caution. (orig.).

  1. MR imaging in recurrent pain after back surgery. A comparative study using standard and high doses of gadolinium contrast agents

    International Nuclear Information System (INIS)

    Aakeson, P.; Jonsson, E.; Holtaas, S.

    1996-01-01

    Purpose: To compare the diagnostic results following injection of (a) a high dose (0.3 mmol/kg b.w.) of gadodiamide injection and (b) the standard dose (0.1 mmol/kg b.w.) of Gd-DTPA, in patients with recurrent symptoms after surgery for lumbar disc herniation. Material and Methods: Twenty patients with recurrent or sustained symptoms after surgery for lumbar disc herniations were examined. MR imaging (0.3 T) was first performed before and after Gd-DTPA at 0.1 mmol/kg b.w., and then within one month (17 patients) or within 3 months (3 patients) before and after gadodiamide injection at 0.3 mmol/kg b.w. The examinations were first evaluated by 2 neuroradiologists blinded to dose but not to patient as the images were presented in pairs. Six months later the same investigators evaluated the examinations again, this time blinded to both dose and patient. Results: At the evaluation in pairs (with the investigators blinded to dose only) the high-dose examinations were considered the most informative (p=0.05). However, at the later evaluation (with the investigators blinded both to dose and patient) no significant difference between high and standard dose was found regarding diagnosis or diagnostic certainty. Conclusion: In this study the high-dose contrast enhancement of MR imaging at 0.3 T did not increase the diagnostic information for differentiating between scar and recurrent hernia. The high-dose images were considered more informative when evaluated in pairs, but gave no additional or different information when evaluated separately. The study also indicated that comparisons in pairs should be interpreted with caution. (orig.)

  2. A systematic review of studies comparing body image concerns among female college athletes and non-athletes, 1997-2012.

    Science.gov (United States)

    Varnes, Julia R; Stellefson, Michael L; Janelle, Christopher M; Dorman, Steven M; Dodd, Virginia; Miller, M David

    2013-09-01

    Research prior to 2001 indicated that athletes experienced better body image than non-athletes, with no differences among sport types. Since then, female athletes have become increasingly sexually objectified in the media, and the sociocultural beauty ideal has shifted to emphasize appearing both athletic and thin. Part I of this paper explores the literature describing these changes. Part II presents a systematic and comprehensive literature review of 10 recent studies comparing body image concerns (BIC) among collegiate female athletes and non-athletes to identify the current status of BIC in female athletes. Findings indicate that involvement in collegiate athletics provides some protection from BIC; however, this protection appears attenuated for athletes in more feminine sports (e.g., gymnastics), and higher level athletes (Division I). Researchers should examine how sociocultural pressures unrelated to competition predict female athletes' BIC using measures that focus on objectification, positive body image, body functionality, and thin- and athletic-ideal internalization. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. The cervical spinal cord in neuromyelitis optica patients: A comparative study with multiple sclerosis using diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pessôa, Fernanda Miraldi Clemente, E-mail: fernandamiraldi@hotmail.com [Federal University of Rio de Janeiro, Medical Student, Rua Rodolpho Paulo Rocco, 255, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ (Brazil); Lopes, Fernanda Cristina Rueda, E-mail: frueda81@hotmail.com [Department of Radiology, Federal University of Rio de Janeiro, Avenida das Américas, 4666 sl 325, Barra da Tijuca, Rio de Janeiro, RJ (Brazil); Costa, João Victor Altamiro, E-mail: victoraltamiro@gmail.com [Department of Radiology, Federal University of Rio de Janeiro, Rua Rodolpho Paulo Rocco, 255, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ (Brazil); Leon, Soniza Vieira Alves, E-mail: sonizavleon@globo.com [Department of Neurology, Federal University of Rio de Janeiro, Rua Rodolpho Paulo Rocco, 255, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ (Brazil); Domingues, Romeu Côrtes, E-mail: romeu@CDPi.com.br [CDPI – Clínica de Diagnóstico Por Imagem, Avenida das Américas, 4666 sl 325, Barra da Tijuca, Rio de Janeiro, RJ (Brazil); Gasparetto, Emerson Leandro, E-mail: egasparetto@gmail.com [Department of Radiology, Federal University of Rio de Janeiro, Avenida das Américas, 4666 sl 325, Barra da Tijuca, Rio de Janeiro, RJ (Brazil); CDPI – Clínica de Diagnóstico Por Imagem, Avenida das Américas, 4666 sl 325, Barra da Tijuca, Rio de Janeiro, RJ (Brazil)

    2012-10-15

    Introduction: This study aims to evaluate “in vivo” the integrity of the normal-appearing spinal cord in patients with neuromyelitis optica (NMO), using diffusion tensor MR imaging, comparing to controls and patients with multiple sclerosis (MS). Materials and methods: We studied 8 patients with NMO and 17 without any neurologic disorder. Also, 32 MS patients were selected. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were calculated within regions of interest at C2 and C7 levels in the four columns of the spinal cord. Results: At C2, the FA value was decreased in NMO patients compared to MS and controls in the anterior column. Also in this column, RD value showed increase in NMO compared to MS and to controls. The FA value of the posterior column was decreased in NMO in comparison to controls. At C7, AD value was higher in NMO than in MS in the right column. At the same column, MD values were increased in NMO compared to MS and to controls. Conclusions: There is extensive NASC damage in NMO patients, including peripheral areas of the cervical spinal cord, affecting the white matter, mainly caused by demyelination. This suggests a new spinal cord lesion pattern in NMO in comparison to MS.

  4. The cervical spinal cord in neuromyelitis optica patients: A comparative study with multiple sclerosis using diffusion tensor imaging

    International Nuclear Information System (INIS)

    Pessôa, Fernanda Miraldi Clemente; Lopes, Fernanda Cristina Rueda; Costa, João Victor Altamiro; Leon, Soniza Vieira Alves; Domingues, Romeu Côrtes; Gasparetto, Emerson Leandro

    2012-01-01

    Introduction: This study aims to evaluate “in vivo” the integrity of the normal-appearing spinal cord in patients with neuromyelitis optica (NMO), using diffusion tensor MR imaging, comparing to controls and patients with multiple sclerosis (MS). Materials and methods: We studied 8 patients with NMO and 17 without any neurologic disorder. Also, 32 MS patients were selected. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were calculated within regions of interest at C2 and C7 levels in the four columns of the spinal cord. Results: At C2, the FA value was decreased in NMO patients compared to MS and controls in the anterior column. Also in this column, RD value showed increase in NMO compared to MS and to controls. The FA value of the posterior column was decreased in NMO in comparison to controls. At C7, AD value was higher in NMO than in MS in the right column. At the same column, MD values were increased in NMO compared to MS and to controls. Conclusions: There is extensive NASC damage in NMO patients, including peripheral areas of the cervical spinal cord, affecting the white matter, mainly caused by demyelination. This suggests a new spinal cord lesion pattern in NMO in comparison to MS

  5. Coronary artery size and origin imaging in children: a comparative study of MRI and trans-thoracic echocardiography

    International Nuclear Information System (INIS)

    Hussain, Tarique; Mathur, Sujeev; Peel, Sarah A.; Valverde, Israel; Bilska, Karolina; Henningsson, Markus; Botnar, Rene M.; Simpson, John; Greil, Gerald F.

    2015-01-01

    The purpose of this study was to see how coronary magnetic resonance angiography (CMRA) compared to echocardiography for the detection of coronary artery origins and to compare CMRA measurements for coronary dimensions in children with published echocardiographic reference values. Enrolled patients underwent dual cardiac phase CMRA and echocardiography under the same anesthetic. Echocardiographic measurements of the right coronary artery (RCA), left anterior descending (LAD) and left main (LM) were made. CMRA dimensions were assessed manually at the same points as the echocardiographic measurements. The number of proximal LAD branches imaged was also recorded in order to give an estimate of distal coronary tree visualization. Fifty patients (24 boys, mean age 4.0 years (range 18 days to 18 years)) underwent dual-phase CMRA. Coronary origins were identified in 47/50 cases for CMRA (remaining 3 were infants aged 3, 9 and 11 months). In comparison, origins were identified in 41/50 cases for echo (remaining were all older children). CMRA performed better than echocardiography in terms of distal visualization of the coronary tree (median 1 LAD branch vs. median 0; p = 0.001). Bland-Altman plots show poor agreement between echocardiography and CMRA for coronary measurements. CMRA measurements did vary according to cardiac phase (systolic mean 1.90, s.d. 0.05 mm vs. diastolic mean 1.84, s.d. 0.05 mm; p = 0.002). Dual-phase CMRA has an excellent (94 %) success rate for the detection of coronary origins in children. Newborn infants remain challenging and echocardiography remains the accepted imaging modality for this age group. Echocardiographic reference ranges are not applicable to CMRA measurements as agreement was poor between modalities. Future coronary reference values, using any imaging modality, should quote the phase in which it was measured

  6. Computed tomography compared to magnetic resonance imaging in occult or suspect hip fractures. A retrospective study in 44 patients

    Energy Technology Data Exchange (ETDEWEB)

    Collin, David; Goethlin, Jan H. [Sahlgrenska University Hospital, Department of Radiology, Moelndal (Sweden); Geijer, Mats [Lund University, Department of Medical Imaging and Physiology, Skaane University Hospital, Lund (Sweden)

    2016-11-15

    Computed tomography (CT) for evaluation of occult and suspect hip fractures has been proposed as a good second-line investigation. The diagnostic precision compared to magnetic resonance imaging (MRI) is unclear. To compare the diagnostic performance of CT and MRI in a retrospective study on patients with suspect and occult hip fractures. Forty-four elderly consecutive patients with low-energy trauma to the hip were identified where negative or suspect CT was followed by MRI. Primary reporting and review by two observers as well as the diagnostic performance of the two modalities were compared. Surgical treatment and clinical course were used as outcomes. Compared to the primary reports, the CT reviewers found fewer normal and no suspect cases. MRI changed the primary diagnoses in 27 cases, and in 14 and 15 cases, respectively, at review. There was no disagreement on MRI diagnoses. In our patient population, MRI was deemed a more reliable modality for hip fracture diagnosis in comparison to CT. For clinical decision making, MRI seems to have a higher accuracy than CT. A negative CT finding cannot completely rule out a hip fracture in patients where clinical findings of hip fracture persevere. (orig.)

  7. Product-country images as stereotypes: A comparative study of Danish food products in Germany and Turkey

    DEFF Research Database (Denmark)

    Askegaard, Søren; Ger, Güliz

    Executive summary 1. Stereotype research as known from social psychology and political research has only to a limited extent found its way into the field of product-country images. However, recent studies of country-of-origin or country images have taken up stereotypes and related concepts...... such as schemas and cognitive structures. 2. In this study, we examine product-country images in terms of stereotypes. In order to explore stereotypes of country and product meaning, we conducted research on the meanings pertaining to Denmark and Danish food products in two selected cultures: Germany and Turkey...... with Turkish food culture. 5. Other studies show that Danish exporters tend to have a more positive idea of Danish products' and Denmark's image on export markets than our results can confirm. Thus, there seems to be a clash between the way Danish exporters think others see us and the actual image on export...

  8. Multimodal imaging in the elastase-induced aneurysm model in rabbits: a comparative study using serial DSA, MRA and CTA

    International Nuclear Information System (INIS)

    Doerfler, A.; Becker, W.; Wanke, I.; Goericke, S.; Oezkan, N.; Forsting, M.

    2004-01-01

    Background and Purpose: The elastase-induced aneurysm model in rabbits has proved to be suitable for testing new endovascular occlusion devices. The purpose of this study was to evaluate different imaging modalities for the depiction of anatomy and size of elastase-induced aneurysms and for serial follow-up imaging. Materials and Methods: Elastase-induced aneurysms were created in eight Chinchilla bastard rabbits by endoluminal incubation of porcine elastase. Serial imaging was performed using intravenous DSA (IVDSA), contrast-enhanced MRA (CEMRA), and time-of-flight MRA (TOF) 14 days, 4 weeks and 3 months after aneurysm creation. Intraarterial DSA (IADSA) and CT angiography (CTA) were performed after 3 months. Aneurysm size and geometry (height H, width W, neck width N) were compared. Results: On IVDSA after two weeks mean aneurysm height was 6.2 mm (range 2.8-11.0 mm), mean aneurysm neck width was 2.7 mm (range 2.0-4.2 mm) and mean aneurysm neck width was 2.7 mm (range 2.0-4.2 mm). We did not observed any statistically significant change in aneurysm dimensions during follow-up at 4 weeks (CEMRA: H: 5.4, W: 2.4, N: 2.4; TOF: H: 5.7, W: 2.4, N: 2.7) and 3 months (CEMRA: H: 5.8, W: 2.6, N: 2.6; TOF: H: 6.9, W: 2.8, N: 3.0). Aneurysm dimensions could be best seen on IADSA (H: 6.2, W: 3.0, N: 2.7) with good correlation to CTA (r=0.94; H: 6.1, W: 2.8, N: 2.6), CE-MRA (r=0.92), and TOF (r=0.97). TOF was superior to CEMRA in delineating the aneurysm wall. Conclusions: Serial imaging using MRA, CTA or intravenous and intraarterial angiography is feasible in the elastase-induced aneurysm model. Contrast-enhanced MRA, TOF-MRA and CTA showed good correlation to IADSA and are all suitable for non-invasive pretherapeutic measurement of aneurysm size. (orig.) [de

  9. Comparative study of fast T 2-weighted images using respiratory triggered, breath-hold, fat suppression and phased array multi coil for liver evaluation by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Abbehusen, Cristiane L.; D'Ippolito, Giuseppe; Palacio, Glaucia A.S.; Szejnfeld, Jacob

    2003-01-01

    The objective of this study was to compare both qualitatively and quantitatively six T 2-weighted turbo spin-echo sequences varying the respiratory compensation technique, associating or not fat tissue suppression and using different types of coils. We performed a prospective study of 71 consecutive patients that were submitted to MRI of the liver using a 1.5 T magnet. The six following pulse sequences were used: fat-suppressed respiratory triggered with conventional body coil; breath-hold fat-suppressed with conventional body coil; non-suppressed respiratory triggered with conventional body coil; breath-hold non fat-suppressed with conventional body coil; fat-suppressed respiratory triggered with phased-array multi coil; breath-hold fat-suppressed with phased-array multi coil. Images were analyzed quantitatively by measuring the signal-to-noise ratios and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and the presence of artifacts. Results: the qualitative analysis showed that the mean values obtained with the six sequences were 7.8, 4.6, 7.9, 5.2, 6.7 and 4.6 respectively. The respiratory-triggered sequences were better than the breath-hold sequences in both qualitative and quantitative analysis (p < 0.001). No significant differences in the values of signal-to-noise ratios and in overall image quality were found between the sequences with and without fat suppression (p . 0.05). The sequences using the body coil were similar in terms of image quality (p . 0.05) and better regarding signal-to-noise ratios than those obtained with the phased=array multi coil (p ,0.001). Our qualitative and quantitative results suggest that the best MRI sequences for the valuation of the liver are the sequences with respiratory triggering using a conventional body coil, with or without fat suppression. (author)

  10. Cerebral Anatomy of the Spider Monkey Ateles Geoffroyi Studied Using Magnetic Resonance Imaging. First Report: a Comparative Study with the Human Brain Homo Sapiens

    OpenAIRE

    Chico-Ponce de León, Fernando; Platas-Neri, Diana; Muñoz-Delgado, Jairo; Santillán-Doherty, Ana María; Arenas-Rosas, Rita; Trejo, David; Conde, Rubén; Ojeda-Flores, Rafael; Campos-Romo, Aurelio; Castro-Sierra, Eduardo; Cervantes, Juan José; Braun, Marc

    2009-01-01

    The objective of the present qualitative study was to analyze the morphological aspects of the inner cerebral anatomy of two species of primates, using magnetic resonance images (MRI): spider monkey (A. geoffroyi) and human (H. sapiens), on the basis of a comparative study of the cerebral structures of the two species, focusing upon the brain of the spider monkey and, primarily, its limbic system. In spite of being an endemic Western hemisphere species, a fact which is by its own right intere...

  11. Diagnostic accuracy of an artificial neural network compared with statistical quantitation of myocardial perfusion images. A Japanese multicenter study

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kenichi; Matsuo, Shinro [Kanazawa University Hospital, Kanazawa (Japan); Kudo, Takashi [Nagasaki University Hospital, Nagasaki (Japan); Nakata, Tomoaki [Hakodate Goryoukaku Hospital, Hakodate (Japan); Kiso, Keisuke [National Cerebral and Cardiovascular Center, Suita (Japan); Kasai, Tokuo [Tokyo Medical University Hachioji Medical Center, Hachioji (Japan); Taniguchi, Yasuyo [Hyogo Brain and Heart Center, Himeji (Japan); Momose, Mitsuru [Tokyo Women' s Medical University, Tokyo (Japan); Nakagawa, Masayasu [Akita City Hospital, Akita (Japan); Sarai, Masayoshi [Fujita Health University Hospital, Toyoake (Japan); Hida, Satoshi [Tokyo Medical University Hospital, Tokyo (Japan); Tanaka, Hirokazu [Tokyo Medical University Ibaraki Medical Center, Ibaraki (Japan); Yokoyama, Kunihiko [Public Central Hospital of Matto Ishikawa, Hakusan (Japan); Okuda, Koichi [Kanazawa Medical University, Kahoku (Japan); Edenbrandt, Lars [University of Gothenburg, Gothenburg (Sweden)

    2017-12-15

    Artificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable. The ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest {sup 99m}Tc-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis. The ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were >0.80. The ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease. (orig.)

  12. Diagnostic accuracy of an artificial neural network compared with statistical quantitation of myocardial perfusion images. A Japanese multicenter study

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Matsuo, Shinro; Kudo, Takashi; Nakata, Tomoaki; Kiso, Keisuke; Kasai, Tokuo; Taniguchi, Yasuyo; Momose, Mitsuru; Nakagawa, Masayasu; Sarai, Masayoshi; Hida, Satoshi; Tanaka, Hirokazu; Yokoyama, Kunihiko; Okuda, Koichi; Edenbrandt, Lars

    2017-01-01

    Artificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable. The ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest 99m Tc-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis. The ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were >0.80. The ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease. (orig.)

  13. Atomic imaging by x-ray-fluorescence holography and electron-emission holography: A comparative theoretical study

    International Nuclear Information System (INIS)

    Len, P.M.; Thevuthasan, S.; Fadley, C.S.; Kaduwela, A.P.; Van Hove, M.A.

    1994-01-01

    We consider from a theoretical viewpoint the direct imaging of atoms at and near the surfaces of solids by both x-ray-fluorescence holography (XFH) and electron-emission holography (EEH). The more ideal nature of x-ray scattering makes XFH images superior to those in single-energy EEH. The overlap of real and twin features for pairs of atoms at ±a can cause their XFH or EEH atomic images to cancel for certain combinations of wave vector and |a|. The relative merits of XFH and EEH for structure studies are considered

  14. A comparative study of surface- and volume-based techniques for the automatic registration between CT and SPECT brain images

    International Nuclear Information System (INIS)

    Kagadis, George C.; Delibasis, Konstantinos K.; Matsopoulos, George K.; Mouravliansky, Nikolaos A.; Asvestas, Pantelis A.; Nikiforidis, George C.

    2002-01-01

    Image registration of multimodality images is an essential task in numerous applications in three-dimensional medical image processing. Medical diagnosis can benefit from the complementary information in different modality images. Surface-based registration techniques, while still widely used, were succeeded by volume-based registration algorithms that appear to be theoretically advantageous in terms of reliability and accuracy. Several applications of such algorithms for the registration of CT-MRI, CT-PET, MRI-PET, and SPECT-MRI images have emerged in the literature, using local optimization techniques for the matching of images. Our purpose in this work is the development of automatic techniques for the registration of real CT and SPECT images, based on either surface- or volume-based algorithms. Optimization is achieved using genetic algorithms that are known for their robustness. The two techniques are compared against a well-established method, the Iterative Closest Point--ICP. The correlation coefficient was employed as an independent measure of spatial match, to produce unbiased results. The repeated measures ANOVA indicates the significant impact of the choice of registration method on the magnitude of the correlation (F=4.968, p=0.0396). The volume-based method achieves an average correlation coefficient value of 0.454 with a standard deviation of 0.0395, as opposed to an average of 0.380 with a standard deviation of 0.0603 achieved by the surface-based method and an average of 0.396 with a standard deviation equal to 0.0353 achieved by ICP. The volume-based technique performs significantly better compared to both ICP (p<0.05, Neuman Keuls test) and the surface-based technique (p<0.05, Neuman-Keuls test). Surface-based registration and ICP do not differ significantly in performance

  15. A comparative study for image quality and radiation dose of a cone beam computed tomography scanner and a multislice computed tomography scanner for paranasal sinus imaging.

    Science.gov (United States)

    De Cock, Jens; Zanca, Federica; Canning, John; Pauwels, Ruben; Hermans, Robert

    2015-07-01

    To evaluate image quality and radiation dose of a state of the art cone beam computed tomography (CBCT) system and a multislice computed tomography (MSCT) system in patients with sinonasal poliposis. In this retrospective study two radiologists evaluated 57 patients with sinonasal poliposis who underwent a CBCT or MSCT sinus examination, along with a control group of 90 patients with normal radiological findings. Tissue doses were measured using a phantom model with thermoluminescent dosimeters (TLD). Overall image quality in CBCT was scored significantly higher than in MSCT in patients with normal radiologic findings (p-value: 0.00001). In patients with sinonasal poliposis, MSCT scored significantly higher than CBCT (p-value: 0.00001). The average effective dose for MSCT was 42% higher compared to CBCT (108 μSv vs 63 μSv). CBCT and MSCT are both suited for the evaluation of sinonasal poliposis. In patients with sinonasal poliposis, clinically important structures of the paranasal sinuses can be better delineated with MSCT, whereas in patients without sinonasal poliposis, CBCT turns out to define the important structures of the sinonasal region better. However, given the lower radiation dose, CBCT can be considered for the evaluation of the sinonasal structures in patients with sinonasal poliposis. • CBCT and MSCT are both suited for evaluation of sinonasal poliposis. • Effective dose for MSCT was 42% higher compared to CBCT. • In patients with sinonasal poliposis, clinically important anatomical structures are better delineated with MSCT. • In patients with normal radiological findings, clinically important anatomical structures are better delineated with CBCT.

  16. Perfusion MRI of brain tumours: a comparative study of pseudo-continuous arterial spin labelling and dynamic susceptibility contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jaernum, Hanna; Steffensen, Elena G.; Simonsen, Carsten Wiberg; Jensen, Finn Taagehoej [Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark); Knutsson, Linda [Lund University, Department of Medical Radiation Physics, Lund (Sweden); Fruend, Ernst-Torben [Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark); GE Healthcare - Applied Science Lab Europe, Aalborg (Denmark); Lundbye-Christensen, Soeren [Aalborg Hospital/Aarhus University Hospital, Department of Cardiology, Center for Cardiovascular Research, Aalborg (Denmark); Shankaranarayanan, Ajit [Global Applied Science Lab, GE Healthcare, Menlo Park, CA (United States); Alsop, David C. [Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA (United States); Larsson, Elna-Marie [Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark); Uppsala University Hospital, Department of Radiology, Uppsala (Sweden)

    2010-04-15

    The purpose of this study was to compare the non-invasive 3D pseudo-continuous arterial spin labelling (PC ASL) technique with the clinically established dynamic susceptibility contrast perfusion magnetic resonance imaging (DSC-MRI) for evaluation of brain tumours. A prospective study of 28 patients with contrast-enhancing brain tumours was performed at 3 T using DSC-MRI and PC ASL with whole-brain coverage. The visual qualitative evaluation of signal enhancement in tumour was scored from 0 to 3 (0 = no signal enhancement compared with white matter, 3 = pronounced signal enhancement with equal or higher signal intensity than in grey matter/basal ganglia). The extent of susceptibility artefacts in the tumour was scored from 0 to 2 (0 = no susceptibility artefacts and 2 = extensive susceptibility artefacts (maximum diameter > 2 cm)). A quantitative analysis was performed with normalised tumour blood flow values (ASL nTBF, DSC nTBF): mean value for region of interest (ROI) in an area with maximum signal enhancement/the mean value for ROIs in cerebellum. There was no difference in total visual score for signal enhancement between PC ASL and DSC relative cerebral blood flow (p = 0.12). ASL had a lower susceptibility-artefact score than DSC-MRI (p = 0.03). There was good correlation between DSC nTBF and ASL nTBF values with a correlation coefficient of 0.82. PC ASL is an alternative to DSC-MRI for the evaluation of perfusion in brain tumours. The method has fewer susceptibility artefacts than DSC-MRI and can be used in patients with renal failure because no contrast injection is needed. (orig.)

  17. A comparative study on PET and SPECT image formation systems for a proper scanner choice in a considered PET center

    International Nuclear Information System (INIS)

    Santos, G.R. dos; Oliveira, A. de; Oliveira, C.L. de

    2001-01-01

    Full text: In the last twenty years, the conjunction of technology and research had provided exceptional conditions for improvements on the quality of life, specially on nuclear medicine. In this area, the developed technology is being applied, making available better diagnoses and therapy to a variety of diseases. Since then the short-lived radionuclides were available only in the large physics research centers. The increasing clinical applications have led to the rapid rise in the number of compact cyclotrons throughout the world. All medical cyclotrons currently are suitable for sustaining programs for PET research and clinical application. To date, up to 122 medical cyclotrons have been established worldwide, and Brazil is about to install a new dedicated cyclotron (RDS111 from CTI), to its first PET Center, in Rio de Janeiro. Also the number of scanners worldwide has increased, mainly those based on the positrons emission and annihilation. The better result gotten in the final contrast of the object imposes a comparative study and analysis of the image formation process, either in a system based on a Single Photon Emission Computerized Tomography (SPECT), as well as on Positron Emission Tomography (PET.) This comparative study should at least follow same increasing rates of the new devices with technological advances. That kind of study can be helpful on the decision of what type of scan should be the proper one, to a PET Center, on a specific region. Obviously, many other parameters are involved in that decision, and this discussion and analyses are the main subject of the present work. The objective is to make available a realistic comparative scenario. Many of the new devices have been introduced making progresses. As an example, in the new PET scanners, the reduction of examination time, and the remarkable improvement on the diagnoses based on images. As a consequence, we have a broadening on application, better performance, and making possible the

  18. Study of Six Energy-Window Settings for Scatter Correction in Quantitative 111In Imaging: Comparative analysis Using SIMIND

    International Nuclear Information System (INIS)

    Gomez Facenda, A.; Castillo Lopez, J. P.; Torres Aroche, L. A.; Coca Perez, M. A.

    2013-01-01

    Activity quantification in nuclear medicine imaging is highly desirable, particularly for dosimetry and biodistribution studies of radiopharmaceuticals. Quantitative 111 In imaging is increasingly important with the current interest in therapy using 90 Y-radiolabeled compounds. Photons scattered in the patient are one of the major problems in quantification, which leads to degradation of image quality. The aim of this work was to assess the configuration of energy windows and the best weight factor for the scatter correction in 111 In images. All images were obtained using the Monte Carlo simulation code, Simind, configured to emulate the gamma camera Nucline SPIRIT DH-V. Simulations were validated by a positive agreement between experimental and simulated line-spread functions (LSF) of 99 mTc. It was examined the sensitivity, the scatter-to-total ratio, the contrast and the spatial resolution for scatter-compensated images obtained from six different multi-windows scatter corrections. Taking into consideration the results, the best energy-window setting was two 20% windows centered at 171 and 245keV, together with a 10% scatter window located between the photo peaks at 209keV. (Author)

  19. Initial phantom study comparing image quality in computed tomography using adaptive statistical iterative reconstruction and new adaptive statistical iterative reconstruction v.

    Science.gov (United States)

    Lim, Kyungjae; Kwon, Heejin; Cho, Jinhan; Oh, Jongyoung; Yoon, Seongkuk; Kang, Myungjin; Ha, Dongho; Lee, Jinhwa; Kang, Eunju

    2015-01-01

    The purpose of this study was to assess the image quality of a novel advanced iterative reconstruction (IR) method called as "adaptive statistical IR V" (ASIR-V) by comparing the image noise, contrast-to-noise ratio (CNR), and spatial resolution from those of filtered back projection (FBP) and adaptive statistical IR (ASIR) on computed tomography (CT) phantom image. We performed CT scans at 5 different tube currents (50, 70, 100, 150, and 200 mA) using 3 types of CT phantoms. Scanned images were subsequently reconstructed in 7 different scan settings, such as FBP, and 3 levels of ASIR and ASIR-V (30%, 50%, and 70%). The image noise was measured in the first study using body phantom. The CNR was measured in the second study using contrast phantom and the spatial resolutions were measured in the third study using a high-resolution phantom. We compared the image noise, CNR, and spatial resolution among the 7 reconstructed image scan settings to determine whether noise reduction, high CNR, and high spatial resolution could be achieved at ASIR-V. At quantitative analysis of the first and second studies, it showed that the images reconstructed using ASIR-V had reduced image noise and improved CNR compared with those of FBP and ASIR (P ASIR-V had significantly improved spatial resolution than those of FBP and ASIR (P ASIR-V provides a significant reduction in image noise and a significant improvement in CNR as well as spatial resolution. Therefore, this technique has the potential to reduce the radiation dose further without compromising image quality.

  20. Comparative study between the radiopacity levels of high viscosity and of flowable composite resins, using digital imaging.

    Science.gov (United States)

    Arita, Emiko S; Silveira, Gilson P; Cortes, Arthur R; Brucoli, Henrique C

    2012-01-01

    The development of countless types and trends of high viscosite and flowable composite resins, with different physical and chemical properties applicable to their broad use in dental clinics calls for further studies regarding their radiopacity level. The aim of this study was to evaluate the radiopacity levels of high viscosity and the flowable composite resins, using digital imaging. 96 composite resin discs 5 mm in diameter and 3 mm thick were radiographed and analyzed. The image acquisition system used was the Digora® Phosphor Storage System and the images were analyzed with the Digora software for Windows. The exposure conditions were: 70 kVp, 8 mA, and 0.2 s. The focal distance was 40 cm. The image densities were obtained with the pixel values of the materials in the digital image. Most of the high viscosity composite resins presented higher radiopacity levels than the flowable composite resins, with statistically significant differences between the trends and groups analyzed (P composite resins, Tetric®Ceram presented the highest radiopacity levels and Glacier® presented the lowest. Among the flowable composite resins, Tetric®Flow presented the highest radiopacity levels and Wave® presented the lowest.

  1. Computed tomography versus intravenous urography in diagnosis of acute flank pain from urolithiasis: a randomized study comparing imaging costs and radiation dose

    International Nuclear Information System (INIS)

    Thomson, J.M.Z.; Maling, T.M.J.; Glocer, J.; Mark, S.; Abbott, C.

    2001-01-01

    The equivalent sensitivity of non-contrast computed tomography (NCCT) and intravenous urography (IVU) in the diagnosis of suspected ureteric colic has been established. Approximately 50% of patients with suspected ureteric colic do not have a nephro-urological cause for pain. Because many such patients require further imaging studies, NCCT may obviate the need for these studies and, in so doing, be more cost effective and involve less overall radiation exposure. The present study compares the total imaging cost and radiation dose of NCCT versus IVU in the diagnosis of acute flank pain. Two hundred and twenty-four patients (157 men; mean age 45 years; age range 19-79 years) with suspected renal colic were randomized either to NCCT or IVU. The number of additional diagnostic imaging studies, cost (IVU A$ 136; CTU A$ 173), radiation exposure and imaging times were compared. Of 119(53%) patients with renal obstruction, 105 had no nephro-urological causes of pain. For 21 (20%) of these patients an alternative diagnosis was made at the initial imaging, 10 of which were significant. Of 118 IVU patients, 28 (24%) required 32 additional imaging tests to reach a diagnosis, whereas seven of 106 (6%) NCCT patients required seven additional imaging studies. The average total diagnostic imaging cost for the NCCT group was A$181.94 and A$175.46 for the IVU group (P< 0.43). Mean radiation dose to diagnosis was 5.00 mSv (NCCT) versus 3.50 mSv (IVU) (P < 0.001). Mean imaging time was 30 min (NCCT) versus 75 min (IVU) (P < 0.001). Diagnostic imaging costs were remarkably similar. Although NCCT involves a higher radiation dose than IVU, its advantages of faster diagnosis, the avoidance of additional diagnostic imaging tests and its ability to diagnose other causes makes it the study of choice for acute flank pain at Christchurch Hospital. Copyright (2001) Blackwell Science Pty Ltd

  2. Prostate cancer: a comparative study of {sup 11}C-choline PET and MR imaging combined with proton MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Takako; Lee, Jin; Takahashi, Nobukazu; Oka, Takashi; Shizukuishi, Kazuya; Inoue, Tomio [Yokohama City University School of Medicine, Department of Radiology, Yokohama (Japan); Uemura, Hiroji; Kubota, Yoshinobu [Yokohama City University School of Medicine, Department of Urology, Kanagawa (Japan); Sasaki, Takeshi [Yokohama City University School of Medicine, Department of Pathology, Kanagawa (Japan); Endou, Hisashi [Yokohama City University School of Medicine, Department of Pharmacy, Kanagawa (Japan)

    2005-07-01

    Prostate cancer is difficult to visualise in its early stages using current imaging technology. The present study aimed to clarify the utility of {sup 11}C-choline PET for localising and evaluating cancer lesions in patients with prostate cancer by conducting a prospective comparison with magnetic resonance (MR) imaging combined with proton MR spectroscopy. PET and MR imaging combined with proton MR spectroscopy were performed in 20 patients with prostate cancer. Correlations among the metabolite ratio of choline + creatine to citrate (Cho+Cr/Ci) on MR spectroscopy, serum PSA and maximum standardised uptake value (SUV{sub max}) of {sup 11}C-choline were assessed. The location of the primary lesion was assessed by the site of SUV{sub max} and the laterality of the highest Cho+Cr/Ci ratio and confirmed by examination of surgical pathology specimens (n=16). PET exhibited a diagnostic sensitivity of 100% (20/20) for primary lesions, while the sensitivities of MR imaging and MR spectroscopy were 60% (12/20) and 65% (13/20), respectively. Weak linear correlations were observed between SUV{sub max} and serum PSA (r=0.52, p<0.05), and between SUV{sub max} and Cho+Cr/Ci ratio (r=0.49, p<0.05). Regarding the localisation of main primary lesions, PET results agreed with pathological findings in 13 patients (81%) ({kappa}=0.59), while MR spectroscopy results were in accordance with pathological findings in eight patients (50%) ({kappa}=0.11). This preliminary study suggests that {sup 11}C-choline PET may provide more accurate information regarding the localisation of main primary prostate cancer lesions than MR imaging/MR spectroscopy. A further clinical study of {sup 11}C-choline PET in a large number of patients suspected of prostate cancer will be necessary to determine the clinical utility of {sup 11}C-choline PET in patients who clinically require biopsy. (orig.)

  3. Experiences that Count: A Comparative Study of the ICTY and SCSL in Shaping the Image of Justice

    Directory of Open Access Journals (Sweden)

    Kristin Xueqin Wu

    2013-01-01

    Full Text Available The legitimacy of international criminal trials is not automatic: it is conditional upon endorsement by local communities. If the very communities involved do not 'feel' a sense of justice, these trials would not only contribute little to the post-conflict peace process, but also create a backlash against these international courts and tribunals, tarnishing the image of international criminal justice. Despite its critical importance, this image management process is still at the stage of trial and error. The first outreach programme, established by the International Criminal Tribunal for the former Yugoslavia (ICTY, has been fighting a losing battle against the Tribunal's poor image in the former Yugoslavia region. In contrast, the Special Court for Sierra Leone (SCSL has been highly praised for promoting a holistic experience of 'just'. What causes these differences, and what could be learnt from them? After comparing the various undertakings by these two ad-hoc tribunals - in terms of outreach strategies, press strategies and resource management - this paper draws three lessons for the permanent International Criminal Court (ICC: gaining acceptance, smoothing communication and boosting judicial efficiency.

  4. ROC analysis for evaluating the detectability of image unsharpness due to the patient's movement. Phantom study comparing preview and diagnostic LCDs

    International Nuclear Information System (INIS)

    Tanaka, Rie; Shiraishi, Junji; Takamori, Miho; Watari, Chihiro

    2011-01-01

    The purpose of this study was to evaluate the detectability of image unsharpness due to a patient's movement, a receiver operating characteristic (ROC) analysis was conducted to compare the diagnostic and preview liquid-crystal displays (LCDs). Phantom images that simulated a patient's movement were obtained by using a moving metronome and acrylic plates with a computed radiography (CR) system. A total of 104 images were classified into five groups according to the degrees of image unsharpness determined based on the metronome velocity and exposure time. In an ROC observer study (n=6), a 2-megapixel diagnostic monochrome LCD (2M-LCD) and a 1.3-megapixel general color LCD for preview (1.3M-LCD) were compared in terms of the detection of image unsharpness due to the movement. A statistical test was performed using the multi-reader multi-case (MRMC) method. In the results, the average areas under the ROC curve values for the detection of image unsharpness using the 2M-LCD and 1.3M-LCD were 0.952 and 0.850, respectively. The detection of image unsharpness using the 2M-LCD was significantly better than that using the 1.3M-LCD (p<0.05). In addition, some images with slight unsharpness were identified correctly only using the 2M-LCD. The results suggest that the low-resolution LCD (id est (i.e.), the 1.3M-LCD for preview) had a limitation in identifying image unsharpness due to the patient's movement. Slight unsharpness could be missed in primary image checks performed on a preview monitor equipped with an imaging system. Therefore, the high-resolution LCD (i.e., a 2M-LCD) is necessary when using radiography for diagnostics. (author)

  5. Are digital images good enough? A comparative study of conventional film-screen vs digital radiographs on printed images of total hip replacement

    International Nuclear Information System (INIS)

    Eklund, K.; Jonsson, K.; Lindblom, G.; Lundin, B.; Sanfridsson, J.; Sloth, M.; Sivberg, B.

    2004-01-01

    The aim of this study was to evaluate the inter- and intra-observer variability and to find differences in diagnostic safety between digital and analog technique in diagnostic zones around hip prostheses. In 80 patients who had had a total hip replacement (THR) for more than 2 years, a conventional image and a digital image were taken. Gruen's model of seven distinct regions of interest was used for evaluations. Five experienced radiologists observed the seven regions and noted in a protocol the following distances: stem-cement; cement-bone; and stem-bone. All images were printed on hard copies and were read twice. Weighted kappa, κ w , analyses were used. The two most frequently loosening regions, stem-cement region 1 and cement-bone region 7, were closely analyzed. In region 1 the five observers had an agreement of 86.75-97.92% between analog and digital images in stem-cement, which is a varied κ w 0.29-0.71. For cement-bone region 7 an agreement of 87.21-90.45% was found, which is a varied κ w of 0.48-0.58. All the kappa values differ significantly from nil. The result shows that digital technique is as good as analog radiographs for diagnosing possible loosening of hip prostheses. (orig.)

  6. Are digital images good enough? A comparative study of conventional film-screen vs digital radiographs on printed images of total hip replacement

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, K.; Jonsson, K.; Lindblom, G.; Lundin, B.; Sanfridsson, J.; Sloth, M. [Department of Radiology, Center for Medical Imaging and Physiology, Lund University Hospital, 22185, Lund (Sweden); Sivberg, B. [Department of Nursing, Faculty of Medicine, Lund University, P.O. Box 157, 22100, Lund (Sweden)

    2004-05-01

    The aim of this study was to evaluate the inter- and intra-observer variability and to find differences in diagnostic safety between digital and analog technique in diagnostic zones around hip prostheses. In 80 patients who had had a total hip replacement (THR) for more than 2 years, a conventional image and a digital image were taken. Gruen's model of seven distinct regions of interest was used for evaluations. Five experienced radiologists observed the seven regions and noted in a protocol the following distances: stem-cement; cement-bone; and stem-bone. All images were printed on hard copies and were read twice. Weighted kappa, {kappa}{sub w}, analyses were used. The two most frequently loosening regions, stem-cement region 1 and cement-bone region 7, were closely analyzed. In region 1 the five observers had an agreement of 86.75-97.92% between analog and digital images in stem-cement, which is a varied {kappa}{sub w} 0.29-0.71. For cement-bone region 7 an agreement of 87.21-90.45% was found, which is a varied {kappa}{sub w} of 0.48-0.58. All the kappa values differ significantly from nil. The result shows that digital technique is as good as analog radiographs for diagnosing possible loosening of hip prostheses. (orig.)

  7. A comparative study of the value of four imaging methods for the diagnosis of rheumatoid arthritis of the shoulder joint

    International Nuclear Information System (INIS)

    Tsvetkova, S.; Semova, R.; Matalova, A.

    2008-01-01

    The shoulder joint becomes involved later than the peripheral joints of the lower and upper limb in rheumatoid arthritis. The aim of the current study is to determine the value of plain radiography (PR), ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) in detecting bone erosions and soft tissue changes of the shoulder joint in patients with rheumatoid arthritis. 27 patients - 21 women and 6 men, mean age 59 years (range 39 - 78) with confirmed rheumatoid arthritis and a painful shoulder are included in the study. The mean duration of the disease is 10 years and the mean duration of the shoulder symptoms is 4 years. In every patient all the imaging modalities were performed within 30 days. PR shows depicted changes in 20 patients (74%), US - in 25 patients (93%), CT - in 23 patients (85%) and MRI - in 26 patients (96%). US and MRI are more sensitive than CT in depicting small erosions of the humeral head and soft tissue changes. MRI and CT are the best methods for the diagnosis of subchondral and intraosseous bone lesions. The traditionally used PR is less sensitive than the other methods, especially in the evaluation of the soft tissues and the small erosions. (authors)

  8. Comparative analysis of MR imaging, Ictal SPECT and EEG in temporal lobe epilepsy: a prospective IAEA multi-center study

    Energy Technology Data Exchange (ETDEWEB)

    Zaknun, John J. [University Hospital of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Vienna (Austria); IAEA, Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, P.O. Box 100, Wien (Austria); Bal, Chandrasekhar [All India Institute of Medical Sciences, Department of Nuclear Medicine, New Delhi (India); Maes, Alex [Katholieke Universiteit Leuven, Leuven (Belgium); AZ Groeninge, Department of Nuclear Medicine, Kortrijk (Belgium); Tepmongkol, Supatporn [Chulalongkorn University, Nuclear Medicine Division, Department of Radiology, Bangkok (Thailand); Vazquez, Silvia [Instituto de Investigaciones Neurologicas, FLENI, Department of Radiology, Buenos Aires (Argentina); Dupont, Patrick [Katholieke Universiteit Leuven, Leuven (Belgium); Dondi, Maurizio [Ospedale Maggiore, Department of Nuclear Medicine, Bologna (Italy); International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Vienna (Austria)

    2008-01-15

    MR imaging, ictal single-photon emission CT (SPECT) and ictal EEG play important roles in the presurgical localization of epileptic foci. This multi-center study was established to investigate whether the complementary role of perfusion SPECT, MRI and EEG for presurgical localization of temporal lobe epilepsy could be confirmed in a prospective setting involving centers from India, Thailand, Italy and Argentina. We studied 74 patients who underwent interictal and ictal EEG, interictal and ictal SPECT and MRI before surgery of the temporal lobe. In all but three patients, histology was reported. The clinical outcome was assessed using Engel's classification. Sensitivity values of all imaging modalities were calculated, and the add-on value of SPECT was assessed. Outcome (Engel's classification) in 74 patients was class I, 89%; class II, 7%; class III, 3%; and IV, 1%. Regarding the localization of seizure origin, sensitivity was 84% for ictal SPECT, 70% for ictal EEG, 86% for MRI, 55% for interictal SPECT and 40% for interictal EEG. Add-on value of ictal SPECT was shown by its ability to correctly localize 17/22 (77%) of the seizure foci missed by ictal EEG and 8/10 (80%) of the seizure foci not detected by MRI. This prospective multi-center trial, involving centers from different parts of the world, confirms that ictal perfusion SPECT is an effective diagnostic modality for correctly identifying seizure origin in temporal lobe epilepsy, providing complementary information to ictal EEG and MRI. (orig.)

  9. Comparative analysis of MR imaging, Ictal SPECT and EEG in temporal lobe epilepsy: a prospective IAEA multi-center study

    International Nuclear Information System (INIS)

    Zaknun, John J.; Bal, Chandrasekhar; Maes, Alex; Tepmongkol, Supatporn; Vazquez, Silvia; Dupont, Patrick; Dondi, Maurizio

    2008-01-01

    MR imaging, ictal single-photon emission CT (SPECT) and ictal EEG play important roles in the presurgical localization of epileptic foci. This multi-center study was established to investigate whether the complementary role of perfusion SPECT, MRI and EEG for presurgical localization of temporal lobe epilepsy could be confirmed in a prospective setting involving centers from India, Thailand, Italy and Argentina. We studied 74 patients who underwent interictal and ictal EEG, interictal and ictal SPECT and MRI before surgery of the temporal lobe. In all but three patients, histology was reported. The clinical outcome was assessed using Engel's classification. Sensitivity values of all imaging modalities were calculated, and the add-on value of SPECT was assessed. Outcome (Engel's classification) in 74 patients was class I, 89%; class II, 7%; class III, 3%; and IV, 1%. Regarding the localization of seizure origin, sensitivity was 84% for ictal SPECT, 70% for ictal EEG, 86% for MRI, 55% for interictal SPECT and 40% for interictal EEG. Add-on value of ictal SPECT was shown by its ability to correctly localize 17/22 (77%) of the seizure foci missed by ictal EEG and 8/10 (80%) of the seizure foci not detected by MRI. This prospective multi-center trial, involving centers from different parts of the world, confirms that ictal perfusion SPECT is an effective diagnostic modality for correctly identifying seizure origin in temporal lobe epilepsy, providing complementary information to ictal EEG and MRI. (orig.)

  10. Assessment of in vivo MR imaging compared to physical sections in vitro-A quantitative study of brain volumes using stereology

    DEFF Research Database (Denmark)

    Jelsing, Jacob; Rostrup, Egill; Markenroth, Karin

    2005-01-01

    The object of the present study was to compare stereological estimates of brain volumes obtained in vivo by magnetic resonance imaging (MRI) to corresponding volumes from physical sections in vitro. Brains of ten domestic pigs were imaged using a 3-T scanner. The volumes of different brain....... However, although intraobserver difference of MRI estimates was acceptable, the interobserver difference was not. A statistical highly significant difference of 11-41% was observed between observers for volume estimates of all compartments considered. The study demonstrates that quantitative MRI...

  11. Histological, magnetic resonance imaging, and discographic findings on cervical disc degeneration in cadaver spines. A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yuichiro [Juntendo Univ., Tokyo (Japan). School of Medicine

    1995-11-01

    A total of 210 cervical intervertebral discs were taken at autopsy from 36 cadavers, and underwent both magnetic resonance imaging (MRI) and discography to compare their diagnostic efficacies for investigating degenerative changes in the cervical spine. The age of the subjects had ranged from 43 to 92 years with an average of 68.1 years. Following the autopsy, MRI and discography were performed on the excised cervical spinal column, and the specimen was then prepared for histological examination. The findings were compared with those of the lumbar spine that had previously been reported by Yasuma et al. on 1238 lumbar discs from 197 cadavers ranging in age from 11 to 92 years. The results were as follows: Low intensity in the T2-weighted MRI was well correlated with histological degeneration in the cervical disc. The rate of appearance of the posterior protrusion of the cervical disc on the MRI was in accordance with the degree of histological disc degeneration, but it did not always correspond with histological posterior protrusion. There was a remarkably high incidence for false-positive posterior protrusion on the MRI, which should be kept in mind on reading the MRI. In the comparison of the MRI with the discography, a certain positive correlation was found as for disc degeneration, but not in complete accordance. There was a considerable difference in the patterns of degeneration and in posterior protrusion of the discs between the cervical spine and the lumbar spine. The posterior protrusion in the cervical disc was more likely related to horizontal fissure and hyalinization of the posterior annulus, while posterior protrusion in the lumbar disc was often related to reversed orientation of the bundles and myxomatous degeneration of the posterior annulus. This difference was attributed to the difference in the mechanical properties of the cervical and lumbar spines. (author).

  12. Histological, magnetic resonance imaging, and discographic findings on cervical disc degeneration in cadaver spines. A comparative study

    International Nuclear Information System (INIS)

    Maruyama, Yuichiro

    1995-01-01

    A total of 210 cervical intervertebral discs were taken at autopsy from 36 cadavers, and underwent both magnetic resonance imaging (MRI) and discography to compare their diagnostic efficacies for investigating degenerative changes in the cervical spine. The age of the subjects had ranged from 43 to 92 years with an average of 68.1 years. Following the autopsy, MRI and discography were performed on the excised cervical spinal column, and the specimen was then prepared for histological examination. The findings were compared with those of the lumbar spine that had previously been reported by Yasuma et al. on 1238 lumbar discs from 197 cadavers ranging in age from 11 to 92 years. The results were as follows: Low intensity in the T2-weighted MRI was well correlated with histological degeneration in the cervical disc. The rate of appearance of the posterior protrusion of the cervical disc on the MRI was in accordance with the degree of histological disc degeneration, but it did not always correspond with histological posterior protrusion. There was a remarkably high incidence for false-positive posterior protrusion on the MRI, which should be kept in mind on reading the MRI. In the comparison of the MRI with the discography, a certain positive correlation was found as for disc degeneration, but not in complete accordance. There was a considerable difference in the patterns of degeneration and in posterior protrusion of the discs between the cervical spine and the lumbar spine. The posterior protrusion in the cervical disc was more likely related to horizontal fissure and hyalinization of the posterior annulus, while posterior protrusion in the lumbar disc was often related to reversed orientation of the bundles and myxomatous degeneration of the posterior annulus. This difference was attributed to the difference in the mechanical properties of the cervical and lumbar spines. (author)

  13. Body-image and obesity in adolescence: a comparative study of social-demographic, psychological, and behavioral aspects.

    Science.gov (United States)

    de Sousa, Pedro Miguel Lopes

    2008-11-01

    In current society, body and beauty's cult emerge as one of the main factors of adolescence. That leads adolescents to be dissatisfied with their own appearance, to psychological maladjustment, and nutritional disorders. This quantitative, exploratory, and cross-sectional research evaluates how adolescents perceive their weight and the prevalence of obesity in a sample of adolescents from the district of Viseu (Portugal). It also attempted to compare the relation of body-image and obesity with sociodemographic (school, sex, age, socioeconomic status, family functioning), psychological (self-concept, depression, school success) and behavioral aspects (physical inactivity). After data analyses, it was verified that the prevalence of obesity was 8.8% but 12.7% considered themselves obese. These adolescents had higher physical inactivity, poorer family functioning, a lower self-concept, and a higher depression index. The really obese adolescents were older and had poorer academic results. Obesity was higher in boys, but girls perceived themselves more as being obese. In conclusion, it is essential to evaluate weight perception in addition to body mass index (BMI), because the main problem could be related not only to being obese, but also to the perception of having a higher than ideal weight.

  14. Comparative study of image quality between axial T2-weighted BLADE and turbo spin-echo MRI of the upper abdomen on 3.0 T.

    Science.gov (United States)

    Zhang, Lin; Tian, ChunMei; Wang, PeiYuan; Chen, Liang; Mao, XiJin; Wang, ShanShan; Wang, Xu; Dong, JingMin; Wang, Bin

    2015-09-01

    To compare image quality of turbo spin-echo (TSE) with BLADE [which is also named periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER)] on magnetic resonance imaging (MRI) for upper abdomen. This study involved the retrospective evaluation of 103 patients (63 males, 40 females; age range 19-76 years; median age 53.8 years) who underwent 3.0 T MRI with both conventional TSE T2-weighted imaging (T2WI) and BLADE TSE T2WI. Two radiologists assessed respiratory motion, gastrointestinal peristalsis, and vascular pulsation artifacts, as well as the sharpness of the liver and pancreas edges. Scores for all magnetic resonance (MR) images were recorded. Wilcoxon's rank test was used to compare hierarchical data. Cohen's kappa coefficient was adopted to analyze interobserver consistency. Compared to TSE T2WI, BLADE TSE T2WI reduced all of the examined motion artifacts and increased the sharpness of the liver and pancreas edges (all P image quality.

  15. Prospective study of ultrasound with perflutrene contrast compared to magnetic resonance imaging in the diagnosis of hepatic hemangiomas

    Directory of Open Access Journals (Sweden)

    Joel Schmillevitch

    2011-06-01

    Full Text Available CONTEXT:The incidence of hepatic hemangiomas ranges from 0.4% to 20% in the general population. Conventional ultrasound is usually the first diagnostic method to identify these hemangiomas, typically as an incidental finding. Ultrasonography with second generation contrast materials is being used in various areas of hepatology, yielding similar results to those obtained with computerized tomography and magnetic resonance imaging in the diagnosis of hepatic hemangiomas. OBJECTIVE: To evaluate the agreement between ultrasound with perflutrene contrast and magnetic resonance imaging in the diagnosis of hepatic hemangiomas. METHODS: A total of 37 patients were prospectively examined between January 2006 and August 2008. A total of 57 hepatic nodules were documented in this group as incidental findings on routine ultrasound exams. The 37 patients were administered perflutrene contrast without adverse reactions, and were all submitted to magnetic resonance exams. RESULTS: Conventional ultrasound identified 15 patients with nodules typical of hemangiomas and 22 patients with other nodules. In 35 patients, the contrast characteristics were consistent with hepatic hemangiomas. CONCLUSION: Agreement between the data obtained from ultrasound with contrast and magnetic resonance was 94.5%. In discordant cases, the magnetic resonance diagnosis prevailed. In the case which presented indeterminate findings on contrast ultrasonography, magnetic resonance was repeated after 3 months, confirming the diagnosis of a hepatic hemangioma. A biopsy was performed on the suspected malignant nodule which also confirmed the presence of a hepatic hemangioma. Ultrasonography with contrast has the advantages of being more accessible to the public at large and lower cost than magnetic resonance. The results of our study highlight the need for a new protocol in hepatic nodules incidentally identified on conventional ultrasonography. In the case of typical hemangiomas

  16. Post mortem magnetic resonance imaging in the fetus, infant and child: A comparative study with conventional autopsy (MaRIAS Protocol

    Directory of Open Access Journals (Sweden)

    Thayyil Sudhin

    2011-12-01

    Full Text Available Abstract Background Minimally invasive autopsy by post mortem magnetic resonance (MR imaging has been suggested as an alternative for conventional autopsy in view of the declining consented autopsy rates. However, large prospective studies rigorously evaluating the accuracy of such an approach are lacking. We intend to compare the accuracy of a minimally invasive autopsy approach using post mortem MR imaging with that of conventional autopsy in fetuses, newborns and children for detection of the major pathological abnormalities and/or determination of the cause of death. Methods/Design We recruited 400 consecutive fetuses, newborns and children referred for conventional autopsy to one of the two participating hospitals over a three-year period. We acquired whole body post mortem MR imaging using a 1.5 T MR scanner (Avanto, Siemens Medical Solutions, Enlargen, Germany prior to autopsy. The total scan time varied between 90 to 120 minutes. Each MR image was reported by a team of four specialist radiologists (paediatric neuroradiology, paediatric cardiology, paediatric chest & abdominal imaging and musculoskeletal imaging, blinded to the autopsy data. Conventional autopsy was performed according to the guidelines set down by the Royal College of Pathologists (UK by experienced paediatric or perinatal pathologists, blinded to the MR data. The MR and autopsy data were recorded using predefined categorical variables by an independent person. Discussion Using conventional post mortem as the gold standard comparator, the MR images will be assessed for accuracy of the anatomical morphology, associated lesions, clinical usefulness of information and determination of the cause of death. The sensitivities, specificities and predictive values of post mortem MR alone and MR imaging along with other minimally invasive post mortem investigations will be presented for the final diagnosis, broad diagnostic categories and for specific diagnosis of each system

  17. Comparative Studies for What?

    Directory of Open Access Journals (Sweden)

    Pedro Guedes de Carvalho

    2017-12-01

    Education Society (BCES & the International Society for Comparative Physical Education and Sport (ISCPES - will jointly organize an International Conference on Sport Governance around the World. Sports and Physical Education are facing complex problems worldwide, which need to be solved. For health reasons, a vast number of organizations are popularizing the belief that physical education and sports are ‘a must’ in order to promote human activity and movement. However, several studies show that modern lifestyles are the main cause for people's inactivity and sedentary lifestyles. Extensive funded programs used to promote healthy lifestyles; sports media advertising several athletes, turning them into global heroes, influencers in a new emerging industry around sports organizations. Therefore, there is a rise in the number of unethical cases and corruption that influence the image of physical education and sports roles. We, the people emotional and physically involved with sports and physical activity must be aware of this, studying, discussing and comparing global facts and events around the world. This Conference aims to offer an incentive to colleagues from all continents to participate and present their latest results on four specific topics: 1. Sport Governance Systems; 2. Ethics and Corruption in Physical Education and Sports Policies; 3. Physical Education and Sport Development; 4. Training Physical Educators and Coaches. Please consider your selves invited to attend. Details in http://bcesconvention.com/

  18. Assessment of left atrial volume and function: a comparative study between echocardiography, magnetic resonance imaging and multi slice computed tomography.

    Science.gov (United States)

    Kühl, J Tobias; Lønborg, Jacob; Fuchs, Andreas; Andersen, Mads J; Vejlstrup, Niels; Kelbæk, Henning; Engstrøm, Thomas; Møller, Jacob E; Kofoed, Klaus F

    2012-06-01

    Measurement of left atrial (LA) maximal volume (LA(max)) using two-dimensional transthoracic echocardiography (TTE) provides prognostic information in several cardiac diseases. However, the relationship between LA(max) and LA function is poorly understood and TTE is less well suited for measuring dynamic LA volume changes. Conversely, cardiac magnetic resonance imaging (CMR) and multi-slice computed tomography (MSCT) appears more appropriate for such measures. We sought to determine the relationship between LA size assessed with TTE and LA size and function assessed with CMR and MSCT. Fifty-four patients were examined 3 months post myocardial infarction with echocardiography, CMR and MSCT. Left atrial volumes and LA reservoir function were assessed by TTE. LA time-volume curves were determined and LA reservoir function (cyclic change and fractional change), passive emptying function (reservoir volume) and pump function (left atrial ejection fraction-LAEF) were derived using CMR and MSCT. Left atrial fractional change and left atrial ejection fraction (LAEF) determined with CMR and MSCT were unrelated to LA(max) enlargement by echocardiography (P = NS). There was an overall good agreement between CMR and MSCT, with a small to moderate bias in LA(max) (4.9 ± 10.4 ml), CC (3.1 ± 9.1 ml) and reservoir volume (3.4 ± 9.1 ml). TTE underestimates LA(max) with up to 32% compared with CMR and MSCT (P fractional change and LAEF is not significantly related to LA(max) measured by TTE. TTE systematically underestimated LA volumes, whereas there are good agreements between MSCT and CMR for volumetric and functional properties.

  19. Comparative study of diffusion weighted imaging and dynamic contrast enhanced MRI for the detection of small breast cancers

    International Nuclear Information System (INIS)

    Tang Jianhua; Yan Fuhua; Zhou Meiling; Ye Fang; Xu Pengju

    2008-01-01

    Objective: To compare the sensitivity of diffusion weighted imaging (DWI) with dynamic contrast enhanced (DCE) MRI for the detection of small breast cancers and to evaluate the clinical value of DWI. Methods: Forty-eight patients with benign (n=25) and malignant (n=45) small breast lesions (≤2 cm) proved by pathology underwent DWI and DCE MRI. The DCE MRI was performed using FLASH sequence and the time-signal intensity curve was drawn. The DWI was performed using GRAPPA- EPI sequence with different b values (800, 1000 s/mm 2 ) and the ADC values of lesions were measured. The sensitivity and specificity of DWI for the detection of small breast cancers were compared with DCE MRI. Results: Forty of 45 small breast cancers and 19 of 25 small benign breast lesions were correctly diagnosed using DCE MRI. The sensitivity and positive predictive value of TIC were 88.9% (40/45) and 87.0% (40/46). With b values of 800 s/mm 2 and 1000 s/mm 2 , the average ADC values of small breast cancers were (1.153±0.192) x 10 -3 and (1.079±0.186) x 10 -3 mm 2 /s, while those of benign ones were (1.473±0.252) x 10 -3 and (1.419 ± 0.255) x 10 -3 mm 2 /s, respectively. There was no significant difference for the ADC values with different b values in the same group (P>0.05), while there was a significant difference between the malignant and the benign lesions (P 2 . Both the sensitivity and positive predictive value of diagnosis were 86.7% (39/45). The abilities of DWI and DCE MRI for the diagnosis of small breast cancers were the same. The sensitivity (93.3%) and positive predictive value (91.3%) were improved with the combination of DCE MRI and DWI. Conclusion: DWI has a high sensitivity for the detection of small breast cancers, the ADC value can provide valuable information in the differential diagnosis. (authors)

  20. A comparative study of mandibular movements with their MR images in patients with internal derangement of the TMJ

    International Nuclear Information System (INIS)

    Miyamoto, Satoshi; Ogawa, Takumi; Hosoda, Yutaka

    1993-01-01

    Thirty one patients with internal derangement of the TMJ and 12 subjects with normal TMJ were selected and their MR imaging and border movements of the mandible were recorded. In addition, the relationship between them were examined. In this study, the disk position and configuration in MR findings were classified as follows. Disk position: superior, anterior and anterolateral (medial and lateral were omitted), grade of anterior disk displacement (with and without reduction): slight, moderate and severe, disk configuration: biconcave, enlargement of posterior band, even thickness and biconvex. Border movements of the mandible were influenced not only by unilateral or bilateral interior derangement but also by with or without reduction of the disk. Border movements in patients with anterolateral disk displacement were more severely restricted than those with anterior disk displacement. Border movements were remarkably limited in patients with slight disk displacement, especially in unilateral cases with reduction of the disk. Border movements in patients with even thickness and biconvex types of disk configuration were a little restricted and rather similar to those of normal subjects. There was significant correlation between border movements and disk position and configuration. It means that measurement of the mandibular movements is very significant to diagnose the condition of internal derangements of the TMJ. (author)

  1. A comparative study of volumetric breast density estimation in digital mammography and magnetic resonance imaging: results from a high-risk population

    Science.gov (United States)

    Kontos, Despina; Xing, Ye; Bakic, Predrag R.; Conant, Emily F.; Maidment, Andrew D. A.

    2010-03-01

    We performed a study to compare methods for volumetric breast density estimation in digital mammography (DM) and magnetic resonance imaging (MRI) for a high-risk population of women. DM and MRI images of the unaffected breast from 32 women with recently detected abnormalities and/or previously diagnosed breast cancer (age range 31-78 yrs, mean 50.3 yrs) were retrospectively analyzed. DM images were analyzed using QuantraTM (Hologic Inc). The MRI images were analyzed using a fuzzy-C-means segmentation algorithm on the T1 map. Both methods were compared to Cumulus (Univ. Toronto). Volumetric breast density estimates from DM and MRI are highly correlated (r=0.90, pwomen with very low-density breasts (peffects in MRI and differences in the computational aspects of the image analysis methods in MRI and DM. The good correlation between the volumetric and the area-based measures, shown to correlate with breast cancer risk, suggests that both DM and MRI volumetric breast density measures can aid in breast cancer risk assessment. Further work is underway to fully-investigate the association between volumetric breast density measures and breast cancer risk.

  2. Comparative study of pulsed-continuous arterial spin labeling and dynamic susceptibility contrast imaging by histogram analysis in evaluation of glial tumors.

    Science.gov (United States)

    Arisawa, Atsuko; Watanabe, Yoshiyuki; Tanaka, Hisashi; Takahashi, Hiroto; Matsuo, Chisato; Fujiwara, Takuya; Fujiwara, Masahiro; Fujimoto, Yasunori; Tomiyama, Noriyuki

    2018-06-01

    Arterial spin labeling (ASL) is a non-invasive perfusion technique that may be an alternative to dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) for assessment of brain tumors. To our knowledge, there have been no reports on histogram analysis of ASL. The purpose of this study was to determine whether ASL is comparable with DSC-MRI in terms of differentiating high-grade and low-grade gliomas by evaluating the histogram analysis of cerebral blood flow (CBF) in the entire tumor. Thirty-four patients with pathologically proven glioma underwent ASL and DSC-MRI. High-signal areas on contrast-enhanced T 1 -weighted images or high-intensity areas on fluid-attenuated inversion recovery images were designated as the volumes of interest (VOIs). ASL-CBF, DSC-CBF, and DSC-cerebral blood volume maps were constructed and co-registered to the VOI. Perfusion histogram analyses of the whole VOI and statistical analyses were performed to compare the ASL and DSC images. There was no significant difference in the mean values for any of the histogram metrics in both of the low-grade gliomas (n = 15) and the high-grade gliomas (n = 19). Strong correlations were seen in the 75th percentile, mean, median, and standard deviation values between the ASL and DSC images. The area under the curve values tended to be greater for the DSC images than for the ASL images. DSC-MRI is superior to ASL for distinguishing high-grade from low-grade glioma. ASL could be an alternative evaluation method when DSC-MRI cannot be used, e.g., in patients with renal failure, those in whom repeated examination is required, and in children.

  3. Analyze image quality and comparative study between conventional and computed radiography applied to the inspection of alloys

    International Nuclear Information System (INIS)

    Machado, Alessandra S.; Oliveira, Davi F.; Silva, Aline S.S.; Nascimento, Joseilson R.; Lopes, Ricardo T.

    2011-01-01

    Piping system design takes into account relevant factors such as: internal coating, dimensioning, vibration system, adequate supports and principally, piping material. Cost is a decisive factor in the phase of material selection. The non-destructive testing method most commonly employed in industry to analyze the structure of an object is radiographic testing. Computed radiography (CR) is a quicker and much more efficient alternative to conventional radiography but, although CR presents numerous advantages, testing procedures are still largely based on trial and error, due to the lack of a consecrated methodology to choose parameters as it exists for conventional radiography. Notwithstanding, this paper presents a study that uses the technique of computed radiography to analyze metal alloys. These metal alloys are used as internal pipe coating aiming to protect against corrosion and cracks. This study seeks to evaluate parameters such as basic spatial resolution, Normalized Signal-to-Noise Ratio (SNRN), contrast, intensity and also to compare conventional radiography with CR. (author)

  4. Astrocytic tumour grading: a comparative study of three-dimensional pseudocontinuous arterial spin labelling, dynamic susceptibility contrast-enhanced perfusion-weighted imaging, and diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Xiao, Hua-Feng; Chen, Zhi-Ye; Wang, Yu-Lin; Wang, Yan; Ma, Lin; Lou, Xin; Gui, Qiu-Ping; Shi, Kai-Ning; Zhou, Zhen-Yu; Zheng, Dan-Dan

    2015-01-01

    We hypothesized that three-dimensional pseudocontinuous arterial spin labelling (pCASL) may have similar efficacy in astrocytic tumour grading as dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI), and the grading accuracy may be further improved when combined with apparent diffusion coefficient (ADC) values. Forty-three patients with astrocytic tumours were studied using diffusion weighted imaging (DWI), pCASL, and DSC-PWI. Histograms of ADC and normalized tumour cerebral blood flow values (nCBF on pCASL and nrCBF on DSC-PWI) were measured and analyzed. The mean 10 % ADC value was the DWI parameter that provided the best differentiation between low-grade astrocytoma (LGA) and high-grade astrocytoma (HGA). The nCBF and nrCBF (1.810 ± 0.979 and 2.070 ± 1.048) in LGA were significantly lower than those (4.505 ± 2.270 and 5.922 ± 2.630) in HGA. For differentiation between LGA and HGA, the cutoff values of 0.764 x 10 -3 mm 2 /s for mean 10 % ADC, 2.374 for nCBF, and 3.464 for nrCBF provided the optimal accuracy (74.4 %, 86.1 %, and 88.6 %, respectively). Combining the ADC values with nCBF or nrCBF could further improve the grading accuracy to 97.7 % or 95.3 %, respectively. pCASL is an alternative to DSC-PWI for astrocytic tumour grading. The combination of DWI and contrast-free pCASL offers a valuable choice in patients with risk factors. (orig.)

  5. Astrocytic tumour grading: a comparative study of three-dimensional pseudocontinuous arterial spin labelling, dynamic susceptibility contrast-enhanced perfusion-weighted imaging, and diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hua-Feng [302 Hospital of Chinese People' s Liberation Army, Department of Radiology, Beijing (China); Chen, Zhi-Ye; Wang, Yu-Lin; Wang, Yan; Ma, Lin [People' s Liberation Army General Hospital, Department of Radiology, Beijing (China); Lou, Xin [People' s Liberation Army General Hospital, Department of Radiology, Beijing (China); University of California, Department of Neurology, Los Angeles, CA (United States); Gui, Qiu-Ping [People' s Liberation Army General Hospital, Department of Pathology, Beijing (China); Shi, Kai-Ning; Zhou, Zhen-Yu; Zheng, Dan-Dan [General Electric Healthcare (China) Co., Ltd., Beijing; Wang, Danny J.J. [University of California, Department of Neurology, Los Angeles, CA (United States)

    2015-12-15

    We hypothesized that three-dimensional pseudocontinuous arterial spin labelling (pCASL) may have similar efficacy in astrocytic tumour grading as dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI), and the grading accuracy may be further improved when combined with apparent diffusion coefficient (ADC) values. Forty-three patients with astrocytic tumours were studied using diffusion weighted imaging (DWI), pCASL, and DSC-PWI. Histograms of ADC and normalized tumour cerebral blood flow values (nCBF on pCASL and nrCBF on DSC-PWI) were measured and analyzed. The mean 10 % ADC value was the DWI parameter that provided the best differentiation between low-grade astrocytoma (LGA) and high-grade astrocytoma (HGA). The nCBF and nrCBF (1.810 ± 0.979 and 2.070 ± 1.048) in LGA were significantly lower than those (4.505 ± 2.270 and 5.922 ± 2.630) in HGA. For differentiation between LGA and HGA, the cutoff values of 0.764 x 10{sup -3} mm{sup 2}/s for mean 10 % ADC, 2.374 for nCBF, and 3.464 for nrCBF provided the optimal accuracy (74.4 %, 86.1 %, and 88.6 %, respectively). Combining the ADC values with nCBF or nrCBF could further improve the grading accuracy to 97.7 % or 95.3 %, respectively. pCASL is an alternative to DSC-PWI for astrocytic tumour grading. The combination of DWI and contrast-free pCASL offers a valuable choice in patients with risk factors. (orig.)

  6. Diagnostic assessment of painless microhematuria: prospective study comparing image quality, assessibility and diagnostic certainty of multidetector-row CT and intravenous pyelography within a single examination

    International Nuclear Information System (INIS)

    Boehm, T.; John, H.; Ruedi, C.; Marincek, B.; Wildermuth, S.; Michael, M.

    2005-01-01

    Purpose: The purpose of this study is to prospectively compare intravenous pyelography (IVP) and combined unenhanced and excretory phase multidetector-row CT (MDCT) with respect to image quality, diagnostic certainty and diagnostic concordance with the final clinical diagnosis in patients with painless microhematuria. Materials and Methods: Unenhanced MDCT, IVP and excretory phase MDCT were performed in 59 consecutive patients (21 women, 38 men, mean age 56±19 years, range 23-83 years) with painless microhematuria of unknown origin during a single examination with a single contrast media application (100 ml, non-ionic iodinate contrast media). Images were assessed by two experienced urogenital radiologists in consensus for image quality, diagnostic certainty of stone detection, obstruction, parenchymal lesions and morphological distinctive features. Imaging diagnoses of MDCT and IVP were compared with the final clinical diagnoses. In case of failure to detect an relevant pathology, the final clinical diagnosis was established after a mean follow-up period of 18±6 months (10 months to 2 years). Costs and radiation exposure of IVP and MDCT were compared. Results: MDCT scan performed better than IVP in terms of image quality for all regarded variables. Image quality of MDCT was rated in all parameters as very good or good; the image quality of IVP differed in a wide range. MDCT and IVP reached a sensitivity of 100% and 50% for stone detection (n=14, p=0.008), respectively. Two bladder stones were not detected by IVU but correctly seen with MDCT. MDCT and IVP were unsatisfactory for detecting transitional cell carcinomas (n=4, 2 of 4 detected with MDCT, 0 of 4 detected with IVU). One false positive transitional cell carcinoma was detected with IVP, none with MDCT. Additional relevant pathological changes (one teratoma, one abdominal aortic aneurysma and one abscess) were detected using MDCT but missed with IVP. In 38 of 59 patients (64%) imaging and clinical follow

  7. A comparative study of 99Tcm-MIBI exercise myocardial perfusion imaging and the coronary arteriography in the diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    Huang Xiaohong; Yan Aiping; Li Yuren; Hou Zhenwen; Jiang Ningyi; Lu Xianping

    2003-01-01

    Objective: A comparative evaluation of 99 Tc m -MIBI exercise myocardial perfusion imaging (MPI) and coronary arteriography (CAG) in diagnosis of coronary artery disease. Methods: MPI and CAG were performed on 92 patients with clinical equivocal diagnosis of coronary artery disease. The results were comparatively studied. Results: The sensitivity and specificity of MPI were 83.9% and 69.1%. Both modalities matched in 78.3% cases. Conclusion: MPI offers useful information for the diagnosis of coronary artery disease. And patients with a normal MPI don't need a further coronary angiography

  8. A comparative study of 99mTc-HL91 and 99mTc-MIBI imaging in experimental tumor and inflammatory models

    International Nuclear Information System (INIS)

    Cao, W.; Zhang, X.Y.; An, R.

    2002-01-01

    Aim: 99m Tc-HL91 is a newly developed hypoxic imaging agent for ischemic myocardium and tumor imaging. 99m Tc-MIBI is one of imaging agent for mammary tumor imaging. The aim of this experiment is to evaluate the diagnostic value of 99m Tc-HL91 in detection of solid tumor in experimental tumor and inflammatory models, via comparative study with 99m Tc-MIBI. Material and Methods: HL91 kits was provided by China Nine Star Co. Three kinds of bearing solid neoplasm mice groups (bearing Ehrlich carcinoma mice, bearing H 22 carcinoma mice and bearing human ovarian COC 1 neoplasm nude mice) and two inflammatory model groups (chemical and bacterial inflammation) underwent static whole body planar images at 1 and 4 hours post injection of 99m Tc-HL91. Two kinds of bearing neoplasm mice groups (bearing Ehrlich carcinoma mice, bearing H 22 carcinoma mice) and two inflammatory model groups (chemical and bacterial inflammation) underwent static planar images post injection of 99m Tc-MIBI, at early phase (10∼20 minutes) and delayed phase (2 hrs). All of mice were sacrificed at 4 hrs. The tumors, or inflammatory lesions, blood and contralateral muscles were removed, weighed and the radioactivity was measured. Regions of interesting (ROIs) were drawn around tumor, inflammatory lesions and contralateral muscles in planar images, and the radioactivity ratios of target (tumor or inflammatory lesions)-to-blood (T/B), target-to-non target (contralateral muscles) i. e. T/NT was calculated. Results: Neoplasm can be clearly visible in planar images at 1hr and 4 hrs post injection of 99m Tc-HL91 in all tumor models. At same time inflammatory lesions cannot be seen clearly. Neoplasm can be seen in delayed phase in 99m Tc-MIBI groups, but not easy to distinguish them from inflammation. Conclusion: Compared with 99m Tc-MIBI imaging, 99m Tc-HL91 has much more diagnostic value in detection of solid neoplasm, and can distinguish neoplasm from inflammation

  9. Transportal femoral drilling creates more horizontal ACL graft orientation compared to transtibial drilling: A 3D CT imaging study.

    Science.gov (United States)

    Clockaerts, S; Van Haver, A; Verhaegen, J; Vuylsteke, K; Leenders, T; Lagae, K C; Verdonk, P

    2016-06-01

    The principle of anatomic anterior cruciate ligament (ACL) reconstruction is to create a femoral and tibial tunnel that resembles the insertion of the native ACL. Anatomic reconstruction leads to a more horizontal graft orientation that provides more rotational stability. The aim of this study is to investigate the best method to achieve anatomical reconstruction of femoral insertion of the ACL and thus, a more horizontal orientation of the ACL. We compared tunnel position and orientation between transportal femoral drilling technique and transtibial technique. Thirty-two patients were included. Post-operative CT scans were obtained and femur, tibia and ACL tunnels were reconstructed. The position and orientation of tibial and femoral tunnels were quantified using the quadrant method, and femoral tunnel length, ellipticity and posterior wall breakage were assessed. We also investigated clinical outcome. Analyses show that transportal drilled femoral tunnels were situated significantly lower than transtibial drilled tunnels (p<0.0001), resulting in a significantly more horizontal oriented ACL in the transportal group in coronal (p<0.0001) and sagittal plane (p=0.01). No differences were observed in depth of femoral tunnel position (p=0.44). Femoral tunnel length was shorter in the transportal group (p=0.01) with a more ellipsoidal femoral aperture (p=0.01). There were no differences between both groups in tibial position. There were no differences in clinical outcome measure between the transportal and transtibial groups. This study indicates that transportal drilling of the femoral tunnel leads to a more horizontal graft orientation of the ACL, without differences in clinical outcome. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Comparing imaging procedures: techniques and examples. Gastroenterology

    International Nuclear Information System (INIS)

    Malmud, L.S.

    1982-01-01

    The distinct advantages of nuclear medicine procedures, in comparison to radiography, contrast studies, computerized tomography and ultrasound, are emphasized. Scintigraphic methods offer quantitative data regarding function which competing imaging modalities are unable to provide, and make them the studies of choice in the evaluation of gastrointestinal physiology and functional abnormalities

  11. Comparative study on 3 imaging techniques and serum marker CA15-3 in diagnosis of breast cancer

    International Nuclear Information System (INIS)

    Zahng Shiqin; Hu Xin; Li Hong'e; Yan Huaixin

    2009-01-01

    Objective: To investigate the clinical value of detecting breast cancer with 3 imaging techniques(Ultrasound, Full-field digital mammography, Magnetic resonance imagery) and serum marker CA15-3. Methods: Sixty-six pathologically proven patients with breast cancer were examined with Ultrasound before operation, 58 cases were examined with Full-field digital mammography, 30 cases were examined by Magnetic resonance imagery, the serum marker CA15-3 was detected with CLIA in 58 cases. Results: The accurate rates of US, MO and MRI for diagnosis of breast cancer were respectively significantly higher than that of CA15-3(P 0.05) (the accuracy of US was 86.4%, the accuracy of MO was 93.2%, the accuracy of MRI was 96.7%). Conclusion: Ultrasonography,due to its reasonably good accuracy with very low cost, might be selected as the first choice of non-invasive diagnosis of breast cancer. (authors)

  12. Imaging anatomy of dorsal pancreatic artery in patients with diabetes: a comparative study between CTA and DSA

    International Nuclear Information System (INIS)

    Lin Yuning; Li Hui; Yang Xizhang; Chen Ziqian; Tan Jianming; Zhong Qun; Yang Li; Wu Zhixian; Li Huimin; Huang Yisheng

    2011-01-01

    Objective: To investigate the clinical value of 64-section CT angiography (CTA) in detecting the origin of dorsal pancreatic artery (DPA). Methods: Ninety-seven consecutive patients with diabetes received transcatheter infusion of autologous bone marrow-derived stem cell transplantation into DPA. Abdominal CTA was performed in 42 patients before angiography. Celiac trunk, splenic, common hepatic and superior mesenteric arteries were reconstructed in order to locate the origin and traveling course of DPA. A routine angiography of both celiac and superior mesenteric arteries was performed for the demonstration of DPA. Further angiography of splenic and gastroduodenal arteries was carried out if necessary. Taking DSA images as the reference standard, the sensitivity, specificity and accuracy of CTA for DPA detection were calculated. Results: DPA was the main supply artery of pancreas in 85.7% patients (36/42). CTA demonstrated the origin of DPA in 35 cases, although one of which was confirmed to be misjudged (false positive). In seven cases CTA could not demonstrate DPA, and DSA proved that 2 of them was misjudged (false negative). The sensitivity,specificity and accuracy of CTA for DPA detection were 94.4%, 83.3% and 92.9%, respectively. Conclusion: 64-section CTA can accurately detect the origin of main supply artery of pancreas, which is of great value in guiding the interventional procedure for pancreatic diseases. (authors)

  13. Comparative study of rabbit VX2 hepatic implantation tumor and normal liver tissue on magnetic resonance perfusion weighted imaging

    International Nuclear Information System (INIS)

    Jiao Zimei; Wang Xizhen; Wang Bin; Liu Feng; Li Haiqing; Sun Yequan; Dong Peng

    2012-01-01

    Objective: To investigate the value of magnetic resonance (MR) perfusion weighted imaging (PWI) in evaluating the blood perfusion of tumor by analyzing the features and indexes of PWI on rabbit VX2 hepatic implantation tumor and normal liver tissue. Methods: Twenty-four New Zealand White rabbits with VX2 carcinoma were established under direct surgical vision embedding tumor tissue. MR examination was performed at 21 days after the tumor implantation. The signal intensity -time curve of hepatic tumor and normal liver tissue were obtained. Mean time to enhance (MTE), negative enhancement integral (NEI), time to minimum (TM), maximum slope of decrease (MSD) and maximum slope of increase (MSI) were measured. Results: MTE, NEI, TM, MSD, and MSI of the normal liver tissue were 208.341±2.226 ms, 78.334±8.152, 24.059±1.927 ms, 38.221±2.443, and 15.389±2.526, respectively. MTE, NEI, TM, MSD, and MSI of the tumor tissue were 175.437±4.182 ms, 123.203±19.455, 17.061±1.834 ms, 125.740±4.842, and 67.832±2.882, respectively. The MTE and TM of tumor were shorter than those of normal hepatic tissue (P<0.05). NEI, MSD, and MSI of tumor were higher than those of normal hepatic tissue (P<0.05). Conclusion: PWI can distinguish the normal liver tissue from the tumor tissue, which is helpful in evaluating blood perfusion of different hepatic tissues. (authors)

  14. A comparative study of colour and perfusion between two different post surgical scars. Do the laser Doppler imager and the colorimeter measure the same features of a scar?

    Science.gov (United States)

    Mermans, J F; Peeters, W J; Dikmans, R; Serroyen, J; van der Hulst, R R J W; Van den Kerckhove, E

    2013-05-01

    The purpose of this study was to investigate the influence of different located post surgical scars on both perfusion and redness. The pattern of change and correlation between perfusion and redness of post surgical scars is also examined. In this study, we measured redness and perfusion of the abdominal and breast scar of 24 women undergoing breast reconstruction with Deep Inferior Epigastric Perforator Free Flap surgery with the Minolta Chromameter CR-400/410 and the Moor Instruments laser Doppler imager 12IR, respectively, at different intervals post-operatively. The laser Doppler imager gives significantly higher values for the abdominal compared with the breast scar. There was no consistent correlation found between perfusion and redness at the different test moments for both locations. The scores of both parameters were significantly associated after 9 months follow-up for both locations. Scars closed with higher mechanical force show higher perfusion and prolonged activity; and more redness is associated with more perfusion for both post surgical scars. Nevertheless, there was no consistent correlation found between these parameters making the laser Doppler imager and the Colorimeter still non-replaceable instruments. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  15. The Institutional Logic of Images of the Poor and Welfare Recipients. A Comparative Study of British, Swedish and Danish Newspapers

    DEFF Research Database (Denmark)

    Larsen, Christian Albrekt; Dejgaard, Thomas Engel

    2013-01-01

    The article investigates how the poor and welfare recipients are depicted in British, Danish and Swedish newspapers. The study was inspired by American media studies that have documented a negative stereotypic way of portraying the poor and welfare recipients; especially in the case...... they are African-Americans. The article argues that there is an institutional welfare-regime logic behind the way the poor and welfare recipients are depicted in the mass media. It is not only a matter of race. This argument is substantiated by showing that the poor and welfare recipients are a) also depicted...

  16. Usefulness of breast-specific gamma imaging as an adjunct modality in breast cancer patients with dense breast. A comparative study with MRI

    International Nuclear Information System (INIS)

    Kim, Bom Sahn

    2012-01-01

    The aim of this study was to evaluate the adjunctive benefits of breast-specific gamma imaging (BSGI) versus magnetic resonance imaging (MRI) in breast cancer patients with dense breasts. This study included a total of 66 patients (44.1±8.2 years) with dense breasts (breast density >50%) and already biopsy-confirmed breast cancer. All of the patients underwent BSGI and MRI as part of an adjunct modality before the initial therapy. Of 66 patients, the 97 undetermined breast lesions were newly detected and correlated with the biopsy results. Twenty-six of the 97 breast lesions proved to be malignant tumors (invasive ductal cancer, n=16; ductal carcinoma in situ, n=6; mixed or other malignancies, n=4); the remaining 71 lesions were diagnosed as benign tumors. The sensitivity and specificity of BSGI were 88.8% (confidence interval (CI), 69.8-97.6%) and 90.1% (CI, 80.7-95.9%), respectively, while the sensitivity and specificity of MRI were 92.3% (CI, 74.9-99.1%) and 39.4% (CI, 28.0-51.7%), respectively (p<0.0001). MRI detected 43 false-positive breast lesions, 37 (86.0%) of which were correctly diagnosed as benign lesions using BSGI. In 12 malignant lesions <1 cm, the sensitivities of BSGI and MR imaging were 83.3% (CI, 51.6-97.9%) and 91.7% (CI, 61.5-99.8%), respectively. BSGI showed an equivocal sensitivity and a high specificity compared to MRI in the diagnosis of breast lesions. In addition, BSGI had a good sensitivity in discriminating breast cancers ≤1 cm. The results of this study suggest that BSGI could play a crucial role as an adjunctive imaging modality which can be used to evaluate breast cancer patients with dense breasts. (author)

  17. Predictors of Images towards the "Other": A Comparative Study between Jordanian and Greek Pre-Service Teachers

    Science.gov (United States)

    Kostoulas-Makrakis, Nelly; Al-Said, Khaleel; Makrakis, Vassilios; Kalogiannakis, Pella; de Baz, Theodora

    2010-01-01

    The present study examined the perceptions of Jordanian and Greek pre-service teachers (N = 489) towards the "Other" as well as towards tolerance and intolerance. Frequencies, "t"-tests and one-way analysis of variance, as well as multiple regression analyses, were performed for the data analysis. The results show that although…

  18. Operations dashboard: comparative study

    Science.gov (United States)

    Ramly, Noor Nashriq; Ismail, Ahmad Zuhairi; Aziz, Mohd Haris; Ahmad, Nurul Haszeli

    2011-10-01

    In this present days and age, there are increasing needs for companies to monitor application and infrastructure health. Apart from having proactive measures to secure their application and infrastructure, many see monitoring dashboards as crucial investment in disaster preparedness. As companies struggle to find the best solution to cater for their needs and interest for monitoring their application and infrastructure's health, this paper summarizes the studies made on several known off-the-shelf operations dashboard and in-house developed dashboard. A few criteria of good dashboard are collected from previous studies carried out by several researchers and rank them according to importance and business needs. The finalized criteria that will be discussed in later sections are data visualization, performance indicator, dashboard personalization, audit capability and alert/ notification. Comparative studies between several popular dashboards were then carried out to determine whether they met these criteria that we derived from the first exercise. The findings hopefully can be used to educate and provide an overview of selecting the best IT application and infrastructure operations dashboard that suit business needs, thus become the main contribution of this paper.

  19. Dual-energy CT in the assessment of mediastinal lymph nodes: Comparative study of virtual non-contrast and true non-contrast images

    International Nuclear Information System (INIS)

    Yoo, Seon Young; Kim, Yoo Kyung; Cho, Hyun Hae; Choi, Mi Joo; Shim, Sung Shine; Lee, Jeong Kyong; Baek, Seung Yon

    2013-01-01

    To evaluate the reliability of virtual non-contrast (VNC) images reconstructed from contrast-enhanced, dual-energy scans compared with true non-contrast (TNC) images in the assessment of high CT attenuation or calcification of mediastinal lymph nodes. A total of 112 mediastinal nodes from 45 patients who underwent non-contrast and dual-energy contrast-enhanced scans were analyzed. Node attenuation in TNC and VNC images was compared both objectively, using computed tomography (CT) attenuation, and subjectively, via visual scoring (0, attenuation ≤ the aorta; 1, > the aorta; 2, calcification). The relationship among attenuation difference between TNC and VNC images, CT attenuation in TNC images, and net contrast enhancement (NCE) was analyzed. CT attenuation in TNC and VNC images showed moderate agreement (intraclass correlation coefficient, 0.612). The mean absolute difference was 7.8 ± 7.6 Hounsfield unit (HU) (range, 0-36 HU), and the absolute difference was equal to or less than 10 HU in 65.2% of cases (73/112). Visual scores in TNC and VNC images showed fair agreement (κ value, 0.335). Five of 16 nodes (31.3%) which showed score 1 (n = 15) or 2 (n = 1) in TNC images demonstrated score 1 in VNC images. The TNC-VNC attenuation difference showed a moderate positive correlation with CT attenuation in TNC images (partial correlation coefficient [PCC] adjusted by NCE: 0.455) and a weak negative correlation with NCE (PCC adjusted by CT attenuation in TNC: -0.245). VNC images may be useful in the evaluation of mediastinal lymph nodes by providing additional information of high CT attenuation of nodes, although it is underestimated compared with TNC images.

  20. Dual-energy CT in the assessment of mediastinal lymph nodes: Comparative study of virtual non-contrast and true non-contrast images

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Seon Young; Kim, Yoo Kyung; Cho, Hyun Hae; Choi, Mi Joo; Shim, Sung Shine; Lee, Jeong Kyong; Baek, Seung Yon [School of Medicine, Ewha Womans University, Seou (Korea, Republic of)

    2013-06-15

    To evaluate the reliability of virtual non-contrast (VNC) images reconstructed from contrast-enhanced, dual-energy scans compared with true non-contrast (TNC) images in the assessment of high CT attenuation or calcification of mediastinal lymph nodes. A total of 112 mediastinal nodes from 45 patients who underwent non-contrast and dual-energy contrast-enhanced scans were analyzed. Node attenuation in TNC and VNC images was compared both objectively, using computed tomography (CT) attenuation, and subjectively, via visual scoring (0, attenuation ≤ the aorta; 1, > the aorta; 2, calcification). The relationship among attenuation difference between TNC and VNC images, CT attenuation in TNC images, and net contrast enhancement (NCE) was analyzed. CT attenuation in TNC and VNC images showed moderate agreement (intraclass correlation coefficient, 0.612). The mean absolute difference was 7.8 ± 7.6 Hounsfield unit (HU) (range, 0-36 HU), and the absolute difference was equal to or less than 10 HU in 65.2% of cases (73/112). Visual scores in TNC and VNC images showed fair agreement (κ value, 0.335). Five of 16 nodes (31.3%) which showed score 1 (n = 15) or 2 (n = 1) in TNC images demonstrated score 1 in VNC images. The TNC-VNC attenuation difference showed a moderate positive correlation with CT attenuation in TNC images (partial correlation coefficient [PCC] adjusted by NCE: 0.455) and a weak negative correlation with NCE (PCC adjusted by CT attenuation in TNC: -0.245). VNC images may be useful in the evaluation of mediastinal lymph nodes by providing additional information of high CT attenuation of nodes, although it is underestimated compared with TNC images.

  1. Dual-energy CT in the assessment of mediastinal lymph nodes: comparative study of virtual non-contrast and true non-contrast images.

    Science.gov (United States)

    Yoo, Seon Young; Kim, Yookyung; Cho, Hyun Hae; Choi, Mi Joo; Shim, Sung Shine; Lee, Jeong Kyong; Baek, Seung Yon

    2013-01-01

    To evaluate the reliability of virtual non-contrast (VNC) images reconstructed from contrast-enhanced, dual-energy scans compared with true non-contrast (TNC) images in the assessment of high CT attenuation or calcification of mediastinal lymph nodes. A total of 112 mediastinal nodes from 45 patients who underwent non-contrast and dual-energy contrast-enhanced scans were analyzed. Node attenuation in TNC and VNC images was compared both objectively, using computed tomography (CT) attenuation, and subjectively, via visual scoring (0, attenuation ≤ the aorta; 1, > the aorta; 2, calcification). The relationship among attenuation difference between TNC and VNC images, CT attenuation in TNC images, and net contrast enhancement (NCE) was analyzed. CT attenuation in TNC and VNC images showed moderate agreement (intraclass correlation coefficient, 0.612). The mean absolute difference was 7.8 ± 7.6 Hounsfield unit (HU) (range, 0-36 HU), and the absolute difference was equal to or less than 10 HU in 65.2% of cases (73/112). Visual scores in TNC and VNC images showed fair agreement (κ value, 0.335). Five of 16 nodes (31.3%) which showed score 1 (n = 15) or 2 (n = 1) in TNC images demonstrated score 1 in VNC images. The TNC-VNC attenuation difference showed a moderate positive correlation with CT attenuation in TNC images (partial correlation coefficient [PCC] adjusted by NCE: 0.455) and a weak negative correlation with NCE (PCC adjusted by CT attenuation in TNC: -0.245). VNC images may be useful in the evaluation of mediastinal lymph nodes by providing additional information of high CT attenuation of nodes, although it is underestimated compared with TNC images.

  2. Comparative study of gated myocardial perfusion imaging using 99Tcm-tetrofosmin and 99Tcm-sestamibi

    International Nuclear Information System (INIS)

    Wang Ruihua; Ruan Qiao; Sun Ke; Han Xingmin; Sun Bingqi; Xie Xinli; Cheng Bing; Chen Yanlin; Liu Baoping

    2013-01-01

    Objective: To compare the results of 99 Tc m -tetrofosmin (TF) and 99 Tc m -MIBI G-MPI in evaluating left ventricular myocardial perfusion and other functional parameters. Methods: TF and MIBI were both labeled by 99 Tc m and the radiochemical purities were tested. During December 2011 to May 2012, 112 patients who had examinations of CAG and echocardiograph in one week after G-MPI were divided into 99 Tc m -TF group (47 patients) and 99 Tc m -MIBI group (65 patients) by simple random sampling. Patients who suffered from severe arrhythmia, clinically suspicious of myocarditis or cardiomyopathy were excluded. The research was approved by the ethics committee, and all patients signed informed consents. One-day 99 Tc m -TF G-MPI and two-day 99 Tc m -MIBI G-MPI were performed. The left ventricular functional parameters were acquired automatically by Cedars quantitative gated SPECT (QGS) software, including LVEF, EDV, ESV, peak filling rate (PFR), peak ejection rate (PER) and phase standard difference (SD). The data were analyzed using χ 2 test, two-sample t test, paired t test and linear correlation analysis by SPSS 17.0. Results: The radiochemical purities of 99 Tc m -TF and 99 Tc m -MIBI were (97.5±0.4) % and (99.1±0.2) % respectively. The coincidence rates of 99 Tc m -TF and 99 Tc m -MIBI G-MPI with CAG were 88.9% (40/45) and 90.5% (57/63), respectively. There was no significant difference between G-MPI results of the two agents (χ 2 =0.389, P>0.05). There was also no significant difference between left ventricular functional parameters of the two agents (LVEF:(62.60±13.56)% vs (60.52±7.08)%, t=0.940; EDV: (103.3±17.29) ml vs (98.52±19.37) ml, t=1.348; ESV: (41.73±12.69) ml vs (46.05±10.81) ml, t=0.851; PER: (2.73±0.67)EDV/s vs (2.61±1.04) EDV/s, t=0.725; PFR: (2.13±0.80) EDV/s vs (2.07±1.09) EDV/s, t=0.339; phase SD: (5.58±4.16)° vs (5.97±4.64)°, t=0.450; all P>0.05). There was no significant difference between left ventricular functional

  3. A comparative study on generating simulated Landsat NDVI images using data fusion and regression method-the case of the Korean Peninsula.

    Science.gov (United States)

    Lee, Mi Hee; Lee, Soo Bong; Eo, Yang Dam; Kim, Sun Woong; Woo, Jung-Hun; Han, Soo Hee

    2017-07-01

    Landsat optical images have enough spatial and spectral resolution to analyze vegetation growth characteristics. But, the clouds and water vapor degrade the image quality quite often, which limits the availability of usable images for the time series vegetation vitality measurement. To overcome this shortcoming, simulated images are used as an alternative. In this study, weighted average method, spatial and temporal adaptive reflectance fusion model (STARFM) method, and multilinear regression analysis method have been tested to produce simulated Landsat normalized difference vegetation index (NDVI) images of the Korean Peninsula. The test results showed that the weighted average method produced the images most similar to the actual images, provided that the images were available within 1 month before and after the target date. The STARFM method gives good results when the input image date is close to the target date. Careful regional and seasonal consideration is required in selecting input images. During summer season, due to clouds, it is very difficult to get the images close enough to the target date. Multilinear regression analysis gives meaningful results even when the input image date is not so close to the target date. Average R 2 values for weighted average method, STARFM, and multilinear regression analysis were 0.741, 0.70, and 0.61, respectively.

  4. Comparative study of LDR (Manchester system) and HDR image-guided conformal brachytherapy of cervical cancer: patterns of failure, late complications, and survival.

    Science.gov (United States)

    Narayan, Kailash; van Dyk, Sylvia; Bernshaw, David; Rajasooriyar, Chrishanthi; Kondalsamy-Chennakesavan, Srinivas

    2009-08-01

    To compare patterns of failure, late toxicities, and survival in locally advanced cervical cancer patients treated by either low-dose-rate (LDR) or conformal high-dose-rate (HDRc) brachytherapy as a part of curative radiotherapy. A retrospective comparative study of 217 advanced cervix cancer patients was conducted; 90 of these patients received LDR and 127 received HDRc brachytherapy. All patients were staged using International Federation of Gynecology and Obstetrics (FIGO) rules, had pretreatment magnetic resonance imaging (MRI), and were treated with concurrent cisplatin chemoradiotherapy. Both groups matched for FIGO stage, MRI tumor volume, and uterine invasion status. Local and pelvic failures were similar 12-13% and 14% both in both groups. Abdominal and systemic failures in LDR group were 21% and 24%, whereas corresponding failures in HDRc group were 20% and 24%. Sixty-eight percent (87/127) of patients treated by HDRc remained asymptomatic, whereas 42% (38/90) of patients were asymptomatic from the bowel and bladder symptoms after treatment with LDR. The 5-year OS rate was 60% (SE = 4%). The 5-year failure-free survival rate was 55% (SE = 3%). There was no significant difference between the groups. Image-guided HDRc planning led to a large decrease in late radiation effects in patients treated by HDRc. Patterns of failure and survival were similar in patients treated either by LDR or HDRc.

  5. Comparative Study of LDR (Manchester System) and HDR Image-guided Conformal Brachytherapy of Cervical Cancer: Patterns of Failure, Late Complications, and Survival

    International Nuclear Information System (INIS)

    Narayan, Kailash; Dyk, Sylvia van; Bernshaw, David; Rajasooriyar, Chrishanthi; Kondalsamy-Chennakesavan, Srinivas

    2009-01-01

    Purpose: To compare patterns of failure, late toxicities, and survival in locally advanced cervical cancer patients treated by either low-dose-rate (LDR) or conformal high-dose-rate (HDRc) brachytherapy as a part of curative radiotherapy. Materials and Methods: A retrospective comparative study of 217 advanced cervix cancer patients was conducted; 90 of these patients received LDR and 127 received HDRc brachytherapy. All patients were staged using International Federation of Gynecology and Obstetrics (FIGO) rules, had pretreatment magnetic resonance imaging (MRI), and were treated with concurrent cisplatin chemoradiotherapy. Both groups matched for FIGO stage, MRI tumor volume, and uterine invasion status. Results: Local and pelvic failures were similar 12-13% and 14% both in both groups. Abdominal and systemic failures in LDR group were 21% and 24%, whereas corresponding failures in HDRc group were 20% and 24%. Sixty-eight percent (87/127) of patients treated by HDRc remained asymptomatic, whereas 42% (38/90) of patients were asymptomatic from the bowel and bladder symptoms after treatment with LDR. The 5-year OS rate was 60% (SE = 4%). The 5-year failure-free survival rate was 55% (SE = 3%). There was no significant difference between the groups. Conclusions: Image-guided HDRc planning led to a large decrease in late radiation effects in patients treated by HDRc. Patterns of failure and survival were similar in patients treated either by LDR or HDRc.

  6. Evaluation of focus laterality in temporal lobe epilepsy: a quantitative study comparing double inversion-recovery MR imaging at 3T with FDG-PET.

    Science.gov (United States)

    Morimoto, Emiko; Okada, Tomohisa; Kanagaki, Mitsunori; Yamamoto, Akira; Fushimi, Yasutaka; Matsumoto, Riki; Takaya, Shigetoshi; Ikeda, Akio; Kunieda, Takeharu; Kikuchi, Takayuki; Paul, Dominik; Miyamoto, Susumu; Takahashi, Ryosuke; Togashi, Kaori

    2013-12-01

    To quantitatively compare the diagnostic capability of double inversion-recovery (DIR) with F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for detection of seizure focus laterality in temporal lobe epilepsy (TLE). This study was approved by the institutional review board, and written informed consent was obtained. Fifteen patients with TLE and 38 healthy volunteers were enrolled. All magnetic resonance (MR) images were acquired using a 3T-MRI system. Voxel-based analysis (VBA) was conducted for FDG-PET images and white matter segments of DIR images (DIR-WM) focused on the whole temporal lobe (TL) and the anterior part of the temporal lobe (ATL). Distribution of hypometabolic areas on FDG-PET and increased signal intensity areas on DIR-WM were evaluated, and their laterality was compared with clinically determined seizure focus laterality. Correct diagnostic rates of laterality were evaluated, and agreement between DIR-WM and FDG-PET was assessed using κ statistics. Increased signal intensity areas on DIR-WM were located at the vicinity of the hypometabolic areas on FDG-PET, especially in the ATL. Correct diagnostic rates of seizure focus laterality for DIR-WM (0.80 and 0.67 for the TL and the ATL, respectively) were slightly higher than those for FDG-PET (0.67 and 0.60 for the TL and the ATL, respectively). Agreement of laterality between DIR-WM and FDG-PET was substantial for the TL and almost perfect for the ATL (κ = 0.67 and 0.86, respectively). High agreement in localization between DIR-WM and FDG-PET and nearly equivalent detectability of them show us an additional role of MRI in TLE. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

  7. Neovascularization in Vertebral Artery Atheroma-A Dynamic Contrast-Enhanced Magnetic Resonance Imaging-Based Comparative Study in Patients with Symptomatic and Asymptomatic Carotid Artery Disease.

    Science.gov (United States)

    Usman, Ammara; Yuan, Jianmin; Patterson, Andrew J; Graves, Martin J; Varty, Kevin; Sadat, Umar; Gillard, Jonathan H

    2018-05-24

    Atherosclerosis is a systemic inflammatory disease intertwined with neovascularization. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) enables the assessment of plaque neovascularization. This study aimed to explore the systemic nature of atherosclerosis by assessing difference in severity of neovascularization as quantified by DCE-MRI of vertebral arteries (VAs) between patients with symptomatic and asymptomatic carotid artery disease. Ten consecutive patients with asymptomatic VA stenosis and concomitant symptomatic carotid artery disease (group 1) and 10 consecutive patients with asymptomatic VA stenosis and concomitant asymptomatic carotid artery disease (group 2) underwent 3-dimensional DCE-MRI of their cervical segment of VAs. A previously validated pharmacokinetic modeling approach was used for DCE-MRI analysis. K trans was calculated in the adventitia and plaque as a measure of neovessel permeability. Both patient groups were comparable for demographics and comorbidities. Mean luminal stenosis was comparable for both groups (54.4% versus 52.27%, P = .32). Group 1 had higher adventitial K trans and plaque K trans (.08 ± .01 min -1 , .07 ± .01 min -1 ) compared with Group 2 (.06 ± .01 min -1 , .06 ± .01 min -1 ) (P = .004 and .03, respectively). Good correlation was present among the two image analysts (intraclass correlation coefficient = .78). Vertebral Artery atheroma of patients with symptomatic carotid artery disease had increased neovessel permeability compared with the patients with asymptomatic carotid artery disease. These findings are consistent with the hypothesis that atherosclerosis is a systemic inflammatory disease. The VA atherosclerosis is likely to have increased severity of neovascularization if another arterial territory is symptomatic in the same patient cohort. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  8. Comparative waste forms study

    International Nuclear Information System (INIS)

    Wald, J.W.; Lokken, R.O.; Shade, J.W.; Rusin, J.M.

    1980-12-01

    A number of alternative process and waste form options exist for the immobilization of nuclear wastes. Although data exists on the characterization of these alternative waste forms, a straightforward comparison of product properties is difficult, due to the lack of standardized testing procedures. The characterization study described in this report involved the application of the same volatility, mechanical strength and leach tests to ten alternative waste forms, to assess product durability. Bulk property, phase analysis and microstructural examination of the simulated products, whose waste loading varied from 5% to 100% was also conducted. The specific waste forms investigated were as follows: Cold Pressed and Sintered PW-9 Calcine; Hot Pressed PW-9 Calcine; Hot Isostatic Pressed PW-9 Calcine; Cold Pressed and Sintered SPC-5B Supercalcine; Hot Isostatic pressed SPC-5B Supercalcine; Sintered PW-9 and 50% Glass Frit; Glass 76-68; Celsian Glass Ceramic; Type II Portland Cement and 10% PW-9 Calcine; and Type II Portland Cement and 10% SPC-5B Supercalcine. Bulk property data were used to calculate and compare the relative quantities of waste form volume produced at a spent fuel processing rate of 5 metric ton uranium/day. This quantity ranged from 3173 L/day (5280 Kg/day) for 10% SPC-5B supercalcine in cement to 83 L/day (294 Kg/day) for 100% calcine. Mechanical strength, volatility, and leach resistance tests provide data related to waste form durability. Glass, glass-ceramic and supercalcine ranked high in waste form durability where as the 100% PW-9 calcine ranked low. All other materials ranked between these two groupings

  9. Comparative study and implementation of images re processing methods for the tomography by positrons emission: interest of taking into account a priori information; Etude comparative et implementation de methodes de reconstruction d`images pour la tomographie par emission de positons: interet de la prise en compte d`informations a priori

    Energy Technology Data Exchange (ETDEWEB)

    Bouchet, F.

    1996-09-25

    The tomography by positron emission has for aim to explore an organ by injection of a radiotracer and bidimensional representation with processing techniques. The most used in routine is the filtered retro projection that gives smoothed images. this work realizes a comparative study of new techniques. The methods of preservations of contours are studied here, the idea is to use NMR imaging as a priori information. Two techniques of images construction are viewed more particularly: the resolution by pseudo inverse and the Bayesian method. (N.C.).

  10. Flexible image evaluation: iPad versus secondary-class monitors for review of MR spinal emergency cases, a comparative study.

    Science.gov (United States)

    McNulty, Jonathan P; Ryan, John T; Evanoff, Michael G; Rainford, Louise A

    2012-08-01

    Studies have highlighted the potential of handheld viewing devices for rapid diagnosis and increased smartphone usage among physicians and radiologists is known as is the clinical applicability of hand-held devices for computed tomography (CT) spinal injury cases. Magnetic resonance (MR), however, is the accepted gold standard for spinal imaging, providing visualization of both ligament and spinal cord pathology. This study investigated the diagnostic accuracy of the iPad, the most probable alternative display device outside the radiology environment and financially viable alternative, when reviewing emergency spinal MR images, in comparison with secondary-class LCD devices in the case of the interpretation of CT and MR imaging examinations. In total 31 MR cases including both positives (n = 13) containing one of four possible presentations: spinal cord compression, cauda equine syndrome, spinal cord hemorrhage, or spinal cord edema and controls (n = 18) were reviewed. Ziltron iPad software facilitated the display of cases and the receiver operating characteristic (ROC) analysis. Thirteen American Board of Radiology board-certified radiologists reviewed all cases on both displays. Standardized viewing conditions were maintained. Dorfman-Berbaum-Metz multireader-multicase (DBM MRMC) analysis was performed including random readers/random cases, fixed readers/random cases and random readers/fixed cases. No differences of statistical significance (P ≤ .05) could be found in terms of area under the curve, sensitivity and specificity between the iPad and secondary-class display. The iPad performed with equal diagnostic accuracy when compared with the secondary-class LCD device after DBM MRMC analysis, demonstrating the iPad as an option to aid initial review of MR spinal emergency cases. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

  11. High-definition resolution three-dimensional imaging systems in laparoscopic radical prostatectomy: randomized comparative study with high-definition resolution two-dimensional systems.

    Science.gov (United States)

    Kinoshita, Hidefumi; Nakagawa, Ken; Usui, Yukio; Iwamura, Masatsugu; Ito, Akihiro; Miyajima, Akira; Hoshi, Akio; Arai, Yoichi; Baba, Shiro; Matsuda, Tadashi

    2015-08-01

    Three-dimensional (3D) imaging systems have been introduced worldwide for surgical instrumentation. A difficulty of laparoscopic surgery involves converting two-dimensional (2D) images into 3D images and depth perception rearrangement. 3D imaging may remove the need for depth perception rearrangement and therefore have clinical benefits. We conducted a multicenter, open-label, randomized trial to compare the surgical outcome of 3D-high-definition (HD) resolution and 2D-HD imaging in laparoscopic radical prostatectomy (LRP), in order to determine whether an LRP under HD resolution 3D imaging is superior to that under HD resolution 2D imaging in perioperative outcome, feasibility, and fatigue. One-hundred twenty-two patients were randomly assigned to a 2D or 3D group. The primary outcome was time to perform vesicourethral anastomosis (VUA), which is technically demanding and may include a number of technical difficulties considered in laparoscopic surgeries. VUA time was not significantly shorter in the 3D group (26.7 min, mean) compared with the 2D group (30.1 min, mean) (p = 0.11, Student's t test). However, experienced surgeons and 3D-HD imaging were independent predictors for shorter VUA times (p = 0.000, p = 0.014, multivariate logistic regression analysis). Total pneumoperitoneum time was not different. No conversion case from 3D to 2D or LRP to open RP was observed. Fatigue was evaluated by a simulation sickness questionnaire and critical flicker frequency. Results were not different between the two groups. Subjective feasibility and satisfaction scores were significantly higher in the 3D group. Using a 3D imaging system in LRP may have only limited advantages in decreasing operation times over 2D imaging systems. However, the 3D system increased surgical feasibility and decreased surgeons' effort levels without inducing significant fatigue.

  12. Contrast enhancement and morphological findings of hematopoietic regions of bone marrow on MR imaging. Comparative study with spondylitis and vertebral tumors

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Yasuo; Hayashi, Hiromitsu; Matsuura, Maki; Watari, Jun; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan)

    1995-06-01

    The enhanced MR findings of hematopoietic regions in aplastic anemia were compared with those of spondylitis, metastatic vertebral tumors and hematologic neoplasms. The enhanced MR images showed hematopoietic regions to homogeneously enhance and occupy the margin of vertebral bodies, while spondylitis and metastatic tumors appeared as round, inhomogeneously enhancing lesions. MR images of leukemia and myelodysplastic syndrome showed homogeneous enhancement at the margins of vertebrae that was difficult to differentiate from hematopoietic regions. Enhanced MR images were useful in detecting the hematopoietic areas in marrow and differentiating them from spondylitis and metastatic tumors, although further experience is needed to distinguish between tumorous hyperplastic regions and benign hematopoietic regions in marrow. (author).

  13. Patient-specific 3D models created by 3D imaging system or bi-planar imaging coupled with Moiré-Fringe projections: a comparative study of accuracy and reliability on spinal curvatures and vertebral rotation data.

    Science.gov (United States)

    Hocquelet, Arnaud; Cornelis, François; Jirot, Anna; Castaings, Laurent; de Sèze, Mathieu; Hauger, Olivier

    2016-10-01

    The aim of this study is to compare the accuracy and reliability of spinal curvatures and vertebral rotation data based on patient-specific 3D models created by 3D imaging system or by bi-planar imaging coupled with Moiré-Fringe projections. Sixty-two consecutive patients from a single institution were prospectively included. For each patient, frontal and sagittal calibrated low-dose bi-planar X-rays were performed and coupled simultaneously with an optical Moiré back surface-based technology. The 3D reconstructions of spine and pelvis were performed independently by one radiologist and one technician in radiology using two different semi-automatic methods using 3D radio-imaging system (method 1) or bi-planar imaging coupled with Moiré projections (method 2). Both methods were compared using Bland-Altman analysis, and reliability using intraclass correlation coefficient (ICC). ICC showed good to very good agreement. Between the two techniques, the maximum 95 % prediction limits was -4.9° degrees for the measurements of spinal coronal curves and less than 5° for other parameters. Inter-rater reliability was excellent for all parameters across both methods, except for axial rotation with method 2 for which ICC was fair. Method 1 was faster for reconstruction time than method 2 for both readers (13.4 vs. 20.7 min and 10.6 vs. 13.9 min; p = 0.0001). While a lower accuracy was observed for the evaluation of the axial rotation, bi-planar imaging coupled with Moiré-Fringe projections may be an accurate and reliable tool to perform 3D reconstructions of the spine and pelvis.

  14. Minimally invasive, imaging guided virtual autopsy compared to conventional autopsy in foetal, newborn and infant cases: study protocol for the paediatric virtual autopsy trial

    Science.gov (United States)

    2014-01-01

    Background In light of declining autopsy rates around the world, post-mortem MR imaging is a promising alternative to conventional autopsy in the investigation of infant death. A major drawback of this non-invasive autopsy approach is the fact that histopathological and microbiological examination of the tissue is not possible. The objective of this prospective study is to compare the performance of minimally invasive, virtual autopsy, including CT-guided biopsy, with conventional autopsy procedures in a paediatric population. Methods/Design Foetuses, newborns and infants that are referred for autopsy at three different institutions associated with the University of Zurich will be eligible for recruitment. All bodies will be examined with a commercial CT and a 3 Tesla MRI scanner, masked to the results of conventional autopsy. After cross-sectional imaging, CT-guided tissue sampling will be performed by a multifunctional robotic system (Virtobot) allowing for automated post-mortem biopsies. Virtual autopsy results will be classified with regards to the likely final diagnosis and major pathological findings and compared to the results of conventional autopsy, which remains the diagnostic gold standard. Discussion There is an urgent need for the development of alternative post-mortem examination methods, not only as a counselling tool for families and as a quality control measure for clinical diagnosis and treatment but also as an instrument to advance medical knowledge and clinical practice. This interdisciplinary study will determine whether virtual autopsy will narrow the gap in information between non-invasive and traditional autopsy procedures. Trial Registration ClinicalTrials.gov: NCT01888380 PMID:24438163

  15. Diagnosis of right-sided varicocele: A retrospective comparative study between clinical examination, Doppler findings, US imaging and vascular anatomy at phlebography

    International Nuclear Information System (INIS)

    Cariati, Maurizio; Pieri, Stefano; Agresti, Paolo; Cariati, Massimiliano; Candito, Davide Fabio; Damiani, Giovanni; Marzano, Domenico

    2012-01-01

    Historically varicocele is diagnosed almost exclusively on the left side. The introduction of new imaging techniques has allowed the identification and characterization of right varicocele. This study aims to compare the diagnostic accuracy of various imaging techniques to data obtained using phlebography in the diagnosis of right varicocele. Patients treated for isolated right varicocele between 1992 and 2010 were retrospectively identified. Data from clinical examination, Doppler-USS, Color-Doppler-USS and Retrograde Phlebography were collected for each patient. 133 out of 4305 patients (3.1%) presented with an isolated right varicocele. 34 of these patients (25.6%) presented with palpable right varicocele. Doppler-USS identified various degrees of type I right venous reflux in 90 patients (67.7%). Phlebography showed venous reflux in all the patients (133), although with variability in terms of internal spermatic vein anatomy. Right varicocele is characterized by predictable anatomic features. Identification and characterization of these features is useful in guiding percutaneous treatment, allowing to optimize radiological display and reducing failure rate

  16. Diagnosis of right-sided varicocele: A retrospective comparative study between clinical examination, Doppler findings, US imaging and vascular anatomy at phlebography

    Energy Technology Data Exchange (ETDEWEB)

    Cariati, Maurizio, E-mail: davide.candito@libero.it [U.O.C. Radiologia, A.O. San Carlo Borromeo, via Pio II 3, 20153 Milan (Italy); Pieri, Stefano, E-mail: stefano.pieri@scamilloforlanini.rm.it [U.O.C. Diagnostica per Immagini Cardioscienze, A.O. San Camillo - Forlanini, Piazza Carlo Forlanini 1, 00151 Rome (Italy); Agresti, Paolo, E-mail: paolo.agresti@scamilloforlanini.rm.it [U.O.C. Diagnostica per Immagini Cardioscienze, A.O. San Camillo - Forlanini, Piazza Carlo Forlanini 1, 00151 Rome (Italy); Cariati, Massimiliano, E-mail: massimiliano.cariati@kcl.ac.uk [Department of Academic Oncology, King' s College London, 3rd Floor Bermondsey Wing, Guy' s Hospital, Great Maze Pond, London SE1 9RT (United Kingdom); Candito, Davide Fabio, E-mail: davide.candito@yahoo.it [Scuola di Specializzazione in Radiodiagnostica, Facoltà di Medicina e Chirurgia, Università degli studi di Milano, via Festa del Perdono 7, 20122 Milan (Italy); Damiani, Giovanni, E-mail: damiani_giovanni@libero.it [Scuola di Specializzazione in Radiodiagnostica, Facoltà di Medicina e Chirurgia, Università degli studi di Milano, via Festa del Perdono 7, 20122 Milan (Italy); Marzano, Domenico, E-mail: domenico.marzano@scamilloforlanini.rm.it [U.O.C. Urologia, A.O. San Camillo - Forlanini, Piazza Carlo Forlanini 1, 00151 Rome (Italy)

    2012-09-15

    Historically varicocele is diagnosed almost exclusively on the left side. The introduction of new imaging techniques has allowed the identification and characterization of right varicocele. This study aims to compare the diagnostic accuracy of various imaging techniques to data obtained using phlebography in the diagnosis of right varicocele. Patients treated for isolated right varicocele between 1992 and 2010 were retrospectively identified. Data from clinical examination, Doppler-USS, Color-Doppler-USS and Retrograde Phlebography were collected for each patient. 133 out of 4305 patients (3.1%) presented with an isolated right varicocele. 34 of these patients (25.6%) presented with palpable right varicocele. Doppler-USS identified various degrees of type I right venous reflux in 90 patients (67.7%). Phlebography showed venous reflux in all the patients (133), although with variability in terms of internal spermatic vein anatomy. Right varicocele is characterized by predictable anatomic features. Identification and characterization of these features is useful in guiding percutaneous treatment, allowing to optimize radiological display and reducing failure rate.

  17. The effects of breathing motion on DCE-MRI images: Phantom studies simulating respiratory motion to compare CAIPARINHA-VIBE, radial VIBE, and conventional VIBE

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Kyung; Seo, Nieun; Kim, Bohyun; Huh, Jimi; Kim, Jeong Kon; Lee, Seung Soo; KIm, Kyung Won [Dept. of Radiology, and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, In Seong [Siemens Healthcare Korea, Seoul (Korea, Republic of); Nickel, Dominik [MR Application Predevelopment, Siemens Healthcare, Erlangen (Germany)

    2017-04-15

    To compare the breathing effects on dynamic contrast-enhanced (DCE)-MRI between controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA)-volumetric interpolated breath-hold examination (VIBE), radial VIBE with k-space-weighted image contrast view-sharing (radial-VIBE), and conventional VIBE (c-VIBE) sequences using a dedicated phantom experiment. We developed a moving platform to simulate breathing motion. We conducted dynamic scanning on a 3T machine (MAGNETOM Skyra, Siemens Healthcare) using CAIPIRINHA-VIBE, radial-VIBE, and c-VIBE for six minutes per sequence. We acquired MRI images of the phantom in both static and moving modes, and we also obtained motion-corrected images for the motion mode. We compared the signal stability and signal-to-noise ratio (SNR) of each sequence according to motion state and used the coefficients of variation (CoV) to determine the degree of signal stability. With motion, CAIPIRINHA-VIBE showed the best image quality, and the motion correction aligned the images very well. The CoV (%) of CAIPIRINHA-VIBE in the moving mode (18.65) decreased significantly after the motion correction (2.56) (p < 0.001). In contrast, c-VIBE showed severe breathing motion artifacts that did not improve after motion correction. For radial-VIBE, the position of the phantom in the images did not change during motion, but streak artifacts significantly degraded image quality, also after motion correction. In addition, SNR increased in both CAIPIRINHA-VIBE (from 3.37 to 9.41, p < 0.001) and radial-VIBE (from 4.3 to 4.96, p < 0.001) after motion correction. CAIPIRINHA-VIBE performed best for free-breathing DCE-MRI after motion correction, with excellent image quality.

  18. Performance of cone-beam computed tomography and multidetector computed tomography in diagnostic imaging of the midface: A comparative study on Phantom and cadaver head scans

    Energy Technology Data Exchange (ETDEWEB)

    Veldhoen, Simon [University Medical Center Hamburg, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); University Hospital Wuerzburg, Department of Diagnostic and Interventional Radiology, Wuerzburg (Germany); Schoellchen, Maximilian; Hanken, H.; Precht, C.; Heiland, M. [University Medical Center Hamburg, Department of Oral- and Maxillofacial Surgery, Hamburg (Germany); Henes, F.O.; Adam, G.; Regier, M. [University Medical Center Hamburg, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Schoen, G. [University Medical Center Hamburg, Department of Medical Biometry and Epidemiology, Hamburg (Germany); Nagel, H.D. [Science and Technology for Radiology, Buchholz (Germany); Schumacher, U. [University Medical Center Hamburg, Institute of Anatomy, Hamburg (Germany)

    2017-02-15

    To compare multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) regarding radiation, resolution, image noise, and image quality. CBCT and 256-MDCT were compared based on three scan protocols: Standard-dose (∼24 mGy), reduced-dose (∼9 mGy), and low-dose (∼4 mGy). MDCT images were acquired in standard- and high-resolution mode (HR-MDCT) and reconstructed using filtered back projection (FBP) and iterative reconstruction (IR). Spatial resolution in linepairs (lp) and objective image noise (OIN) were assessed using dedicated phantoms. Image quality was assessed in scans of 25 cadaver heads using a Likert scale. OIN was markedly higher in FBP-MDCT when compared to CBCT. IR lowered the OIN to comparable values in standard-mode MDCT only. CBCT provided a resolution of 13 lp/cm at standard-dose and 11 lp/cm at reduced-dose vs. 11 lp/cm and 10 lp/cm in HR-MDCT. Resolution of 10 lp/cm was observed for both devices using low-dose settings. Quality scores of MDCT and CBCT did not differ at standard-dose (CBCT, 3.4; MDCT, 3.3-3.5; p > 0.05). Using reduced- and low-dose protocols, CBCT was superior (reduced-dose, 3.2 vs. 2.8; low dose, 3.0 vs. 2.3; p < 0.001). Using the low-dose protocol, the assessed CBCT provided better objective and subjective image quality and equality in resolution. Similar image quality, but better resolution using CBCT was observed at higher exposure settings. (orig.)

  19. Helical-Tip Needle for Transthoracic Percutaneous Image-Guided Biopsy of Lung Tumors: Results of a Pilot Prospective Comparative Study with a Standard Tru-Cut Needle

    Energy Technology Data Exchange (ETDEWEB)

    Veltri, Andrea, E-mail: andrea.veltri@unito.it; Busso, Marco; Sardo, Diego; Angelino, Valeria; Priola, Adriano M. [University of Torino, Department of Radiology, San Luigi Gonzaga Hospital (Italy); Novello, Silvia [University of Torino, Department of Oncology, San Luigi Gonzaga Hospital (Italy); Barba, Matteo [University of Torino, Department of Radiology, San Luigi Gonzaga Hospital (Italy); Gatti, Gaia; Righi, Luisella [University of Torino, Department of Pathology, San Luigi Gonzaga Hospital (Italy)

    2017-06-15

    PurposeTo prospectively evaluate feasibility and diagnostic performance of the 14-gauge helical-tip (Spirotome™, Cook{sup ®} Medical, Bloomington, USA) needle in transthoracic needle biopsy (TTNB) of lung lesions, compared to a conventional 18-gauge Tru-Cut needle.Materials and MethodsStudy was institutional review board approved, with informed consent obtained. Data from synchronous Spirotome and Tru-Cut image-guided TTNB of 20 consecutive patients with malignant peripheral lung tumors larger than 3 cm were enrolled for pathologic characterization and mutational analysis. Samples obtained with Spirotome and Tru-Cut needle were compared for fragmentation, length, weight, morphologic and immunohistochemistry typifying, tumor cellularity (TC) and DNA concentration.ResultsThe technical success rate for TTNB with Spirotome was 100%, and no major complications occurred. Less fragmentation (mean 2 vs. 3 fragments, P = .418), greater weight (mean 13 vs. 8.5 mg, P = .027) and lower length (mean 10.2 vs. 12.6 mm, P = .174) were observed with Spirotome compared to Tru-Cut needle. Accuracy of Spirotome and Tru-Cut needle in defining cancer histotype was similar (90%). Absolute and relative TC (mean 42 vs. 38, 124 vs. 108/10HPF), and DNA concentration (mean 49.6 vs. 39.0 ng/μl) were higher with Spirotome compared to Tru-Cut needle, with no statistical significance (P = .787 and P = .140, respectively).Conclusions Percutaneous 14-gauge Spirotome TTNB of selected lesions is feasible and accurate. It provides adequate samples for diagnosis, comparable to 18-gauge Tru-Cut needle, with a higher amount of tumor tissue (weight, TC, DNA concentration) even in shorter samples.

  20. Mobile OS Comparative Study

    OpenAIRE

    Joseph, Jyothy; K, Shinto Kurian

    2013-01-01

    In the fast growing mobile revolutionary era, many operating systems are playing vital role in present market. This study is intending to identify the apt and secure mobile based on mobile operating systems capability and user requirements.

  1. Optimal pulse sequence for ferumoxides-enhanced MR imaging used in the detection of hepatocellular carcinoma: a comparative study using seven pulse sequences

    International Nuclear Information System (INIS)

    Kim, Seung Hoon; Choi, Dongil; Lim, Jae Hoon; Lee, Won Jae; Jang, Hyun Jung; Lim, Kyo Keun; Lee, Soon Jin; Cho, Jae Min; Kim, Seung Kwon; Kim, Gab Chul

    2002-01-01

    To identify the optimal pulse sequence for ferumoxides-enhanced magnetic resonance (MR) imaging in the detection of hepatocelluar carcinomas (HCCs). Sixteen patients with 25 HCCs underwent MR imaging following intravenous infusion of ferumoxides. All MR studies were performed on a 1.5-T MR system, using a phased-array coil. Ferumoxides (Feridex IV) at a dose of 15 μmol/Kg was slowly infused intravenously, and axial images of seven sequences were obtained 30 minutes after the end of infusion. The MR protocol included fast spin-echo (FSE) with two echo times (TR3333-8571/TE18 and 90-117), singleshot FSE (SSFSE) with two echo times (TR∞/TE39 and 98), T2-weighted gradient-recalled acquisition in the steady state (GRASS) (TR216/TE20), T2-weighted fast multiplanar GRASS (FMPGR) (TR130/TE8.4-9.5), and T2-weighted fast multiplanar spoiled GRASS (FMPSPGR) (TR130/TE8.4-9.5). Contrast-to-noise ratios (CNRs) of HCCs determined during the imaging sequences formed the basis of quantitative analysis, and images were qualitatively assessed in terms of lesion conspicuity and image artifacts. The diagnostic accuracy of all sequences was assessed using receiver operating characteristic (ROC) analysis. Quantitative analysis revealed that the CNRs of T2-weighted FMPGR and T2-weighted FMPSPGR were significantly higher than those of the other sequences, while qualitative analysis showed that image artifacts were prominent at T2-weighted GRASS imaging. Lesion conspicuity was statistically significantly less clear at SSFSE imaging. In term of lesion detection, T-weighted FMPGR, T2- weighted FMPSPGR, and proton density FSE imaging were statistically superior to the others. T2-weighted FMPGR, T2- weighted FMPSPGR, and proton density FSE appear to be the optimal pulse sequences for ferumoxidesenhanced MR imaging in the detection of HCCs

  2. Comparative Packaging Study

    Science.gov (United States)

    Perchonok, Michele H.; Oziomek, Thomas V.

    2009-01-01

    Future long duration manned space flights beyond low earth orbit will require the food system to remain safe, acceptable and nutritious. Development of high barrier food packaging will enable this requirement by preventing the ingress and egress of gases and moisture. New high barrier food packaging materials have been identified through a trade study. Practical application of this packaging material within a shelf life test will allow for better determination of whether this material will allow the food system to meet given requirements after the package has undergone processing. The reason to conduct shelf life testing, using a variety of packaging materials, stems from the need to preserve food used for mission durations of several years. Chemical reactions that take place during longer durations may decrease food quality to a point where crew physical or psychological well-being is compromised. This can result in a reduction or loss of mission success. The rate of chemical reactions, including oxidative rancidity and staling, can be controlled by limiting the reactants, reducing the amount of energy available to drive the reaction, and minimizing the amount of water available. Water not only acts as a media for microbial growth, but also as a reactant and means by which two reactants may come into contact with each other. The objective of this study is to evaluate three packaging materials for potential use in long duration space exploration missions.

  3. A comparative study for spatial resolution and subjective image characteristics of a multi-slice CT and a cone-beam CT for dental use

    International Nuclear Information System (INIS)

    Watanabe, Hiroshi; Honda, Eiichi; Tetsumura, Akemi; Kurabayashi, Tohru

    2011-01-01

    Purpose: Multi-slice CT (MSCT) and cone-beam CT (CBCT) are widely used in dental practice. This study compared the spatial resolution of these CT systems to elucidate which CT modalities should be selected for various clinical cases. Materials and methods: As MSCT and CBCT apparatuses, Somatom Sensation 64 and 3D Accuitomo instruments, respectively, were used. As an objective evaluation of spatial resolution of these CT systems, modulation transfer function (MTF) analysis was performed employing an over-sampling method. The results of MTF analysis were confirmed with a line-pair test using CATPHAN. As a subjective evaluation, a microstructure visualization ability study was performed using a Jcl:SD rat and a head CT phantom. Results: MTF analysis showed that for the in-plane direction, the z-axis ultrahigh resolution mode (zUHR) of the Sensation 64 and 3D Accuitomo instruments had higher spatial resolutions than the conventional mode (64x) of the Sensation 64, but for the longitudinal direction, the 3D Accuitomo had clearly higher spatial resolution than either mode of the Sensation 64. A line-pair test study and microstructure visualization ability studies confirmed the results for MTF analysis. However, images of the rat and the CT phantom revealed that the 3D Accuitomo demonstrated the failure to visualize the soft tissues along with aliasing and beam-hardening artifacts, which were not observed in the Sensation 64. Conclusions: This study successfully applied spatial resolution analysis using MSCT and CBCT systems in a comparative manner. These findings could help in deciding which CT modality should be selected for various clinical cases.

  4. Comparative Study of 2D and 3D Optical Imaging Systems: Laparoendoscopic Single-Site Surgery in an Ex Vivo Model.

    Science.gov (United States)

    Vilaça, Jaime; Pinto, José Pedro; Fernandes, Sandra; Costa, Patrício; Pinto, Jorge Correia; Leão, Pedro

    2017-12-01

    Usually laparoscopy is performed by means of a 2-dimensional (2D) image system and multiport approach. To overcome the lack of depth perception, new 3-dimensional (3D) systems are arising with the added advantage of providing stereoscopic vision. To further reduce surgery-related trauma, there are new minimally invasive surgical techniques being developed, such as LESS (laparoendoscopic single-site) surgery. The aim of this study was to compare 2D and 3D laparoscopic systems in LESS surgical procedures. All participants were selected from different levels of experience in laparoscopic surgery-10 novices, 7 intermediates, and 10 experts were included. None of the participants had had previous experience in LESS surgery. Participants were chosen randomly to begin their experience with either the 2D or 3D laparoscopic system. The exercise consisted of performing an ex vivo pork cholecystectomy through a SILS port with the assistance of a fixed distance laparoscope. Errors, time, and participants' preference were recorded. Statistical analysis of time and errors between groups was conducted with a Student's t test (using independent samples) and the Mann-Whitney test. In all 3 groups, the average time with the 2D system was significantly reduced after having used the 3D system ( P 3D system. This study suggests that the 3D system may improve the learning curve and that learning from the 3D system is transferable to the 2D environment. Additionally, the majority of participants prefer 3D equipment.

  5. Comparative study between 99Tcm-MDP renal dynamic imaging and measurement of serum cystatin C in evaluation of glomerular function

    International Nuclear Information System (INIS)

    Ji Zeqiang; Miao Weibing

    2010-01-01

    Objective: To compare the difference between 99 Tcm-diethylenetriaminepentaacetic acid ( 99 Tc m -DTPA) renal dynamic imaging and measurement of serum cystatin C in evaluation of glomerular filtration rate (GFR). Methods: One hundred patients were selected at random, 38 cases with hypertension, 35 with nephrosis, 10 with arteriosclerosis obliterans, 9 with diabetes and 8 with other diseases. Evaluation of patients' GFR was made separately by 99 Tc m -DTPA renal dynamic imaging and measurement of serum cystatin C. Results: No significant difference of GFR was found between the two methods (t=1.591, P>0.05 ), and linear correlation was showed as well (r=0.809, P 99 Tc m -DTPA renal dynamic imaging could reveal the individual renal function and provide a more comprehensive evaluation of renal function while the measurement of serum cystatin C was simple and convenient, timesaving, economic, and more suit-able for screening patients' renal function clinically. (authors)

  6. Comparative studies of '18F-FDG PET/CT brain imaging and EEG in preoperative localization of temporal lobe epileptic focus

    International Nuclear Information System (INIS)

    Chen Ziqian; Zhao Chunlei; Liu Yao; Ni Ping; Zhong Qun; Bai Wei; Peng Dexin

    2012-01-01

    Objective: To compare the value of 18 F-FDG PET/CT brain imaging and EEG in preoperative localization of the epileptic focus at the temporal lobe. Methods: A total of 152 patients (108 males, 44 females, age ranged from 3 to 59 years old) with past history of temporal lobe epilepsy were included.All patients underwent 18 F-FDG PET/CT brain imaging and long-range or video EEG, and 29 patients underwent intracranial electrode EEG due to the failure to localize the disease focus by non-invasive methods.Histopathologic findings after operative treatment were considered the gold standard for disease localization. All patients were followed up for at least six months after the operation. The accuracy of the 18 F-FDG PET/CT brain imaging and long-range or video EEG examination were compared using χ 2 test. Results: The accuracy of locating the epileptic focus was 80.92% (123/152) for 18 F-FDG PET/CT brain imaging and 43.42% (66/152) for long-range or video EEG (χ 2 =22.72, P<0.01). The accuracy of locating the epileptic focus for the 29 cases with intracranial electrode EEG was 100%. Conclusions: Interictal 18 F-FDG PET/CT brain imaging is a sensitive and effective method to locate the temporal lobe epileptic focus and is better than long-range or video EEG. The combination of 18 F-FDG PET/CT brain imaging and intracranial electrode EEG examination can further improve the accuracy of locating the epileptic focus. (authors)

  7. Selection of TI for Suppression Fat Tissue of SPAIR and Comparative Study of SPAIR and STIR of Brain Fast SE T2 Weighted Imaging

    International Nuclear Information System (INIS)

    Lee, Hoo Min; Kim, Ham Gyum; Kong, Seok Kyo

    2009-01-01

    The purpose of this research is to seek SPAIR's reversal time (TI) which satisfies two conditions ; maintaining the suppression ability of fat tissue and simultaneously minimizing the inhomogeneity of fat tissue in T2 high-speed spin echo 3.0T magnetic resonance image (MRI) of the brain, and to compare SPAIR with STIR which is fat-suppression technique. The reversal times (TI) of SPAIR protocol are set to 1/2, 1/3, 1/6 and 1/12 of SPAIR TR (420 msec), namely 210 msec (8 people), 140 msec (26 people), 70 msec (26 people) and 35 msec (18 people) and STIR TI is set with 250 msec (26 people). With these parameter sets, we acquired the axis direction 104 images of the brain. In ROI (50 mm 2 ) of output image, signal intensities of the fatty tissue, the muscular tissue, and the background were measured and the CNRs of fatty tissue and the muscular tissue were calculated. The inhomogeneity of the fatty tissue is SD/mean, where SD is the standard deviation and 'mean' is a average fatty tissue signal. Consequently, SPAIR TI is determined on either 1/3 or 1/6 of TR (420 ms) ; 140 ms or 70 ms. Because the difference of statistics in fat-suppression ability and inhomogeneity of fatty tissue is very small (p < 0.001), Selecting 140 ms seems to be better choice for the image quality. Meanwhile, Comparing SPAIR (TI : 140 ms) with STIR, the fat-suppression is not able to be considered statistically (p < 0.252), but the image quality is able to be considered statistically (p < 0.01). In conclusion, SPAIR is better than STIR in the image quality.

  8. Statistical methods of evaluating and comparing imaging techniques

    International Nuclear Information System (INIS)

    Freedman, L.S.

    1987-01-01

    Over the past 20 years several new methods of generating images of internal organs and the anatomy of the body have been developed and used to enhance the accuracy of diagnosis and treatment. These include ultrasonic scanning, radioisotope scanning, computerised X-ray tomography (CT) and magnetic resonance imaging (MRI). The new techniques have made a considerable impact on radiological practice in hospital departments, not least on the investigational process for patients suspected or known to have malignant disease. As a consequence of the increased range of imaging techniques now available, there has developed a need to evaluate and compare their usefulness. Over the past 10 years formal studies of the application of imaging technology have been conducted and many reports have appeared in the literature. These studies cover a range of clinical situations. Likewise, the methodologies employed for evaluating and comparing the techniques in question have differed widely. While not attempting an exhaustive review of the clinical studies which have been reported, this paper aims to examine the statistical designs and analyses which have been used. First a brief review of the different types of study is given. Examples of each type are then chosen to illustrate statistical issues related to their design and analysis. In the final sections it is argued that a form of classification for these different types of study might be helpful in clarifying relationships between them and bringing a perspective to the field. A classification based upon a limited analogy with clinical trials is suggested

  9. Visual rating method and tensor-based morphometry in the diagnosis of mild cognitive impairment and Alzheimer's disease: a comparative magnetic resonance imaging study.

    Science.gov (United States)

    Tuokkola, Terhi; Koikkalainen, Juha; Parkkola, Riitta; Karrasch, Mira; Lötjönen, Jyrki; Rinne, Juha O

    2016-03-01

    Atrophy of the medial temporal lobe (MTL) is the main structural magnetic resonance imaging (MRI) finding in the brain of patients with Alzheimer's disease (AD). However, evaluating the degree of atrophy is still demanding. The visual rating method (VRM) was compared with multi-template tensor-based morphometry (TBM), in terms of its efficacy in diagnosing of mild cognitive impairment (MCI) and AD. Forty-seven patients with MCI, 80 patients with AD and 84 controls were studied. TBM seems to be more sensitive than VRM at the early stage of dementia in the areas of MTL and ventricles. The methods were equally good in distinguishing controls and the MCI group from the AD group. At the frontal areas TBM was better than VRM in all comparisons. A user-friendly VRM is still useful for the clinical evaluation of MCI patients, but multi-template TBM is more sensitive for diagnosing the early stages of dementia. However, TBM is currently too demanding to use for daily clinical work. © The Foundation Acta Radiologica 2015.

  10. Meningiomas: A Comparative Study of 68Ga-DOTATOC, 68Ga-DOTANOC and 68Ga-DOTATATE for Molecular Imaging in Mice

    Science.gov (United States)

    Soto-Montenegro, María Luisa; Peña-Zalbidea, Santiago; Mateos-Pérez, Jose María; Oteo, Marta; Romero, Eduardo; Morcillo, Miguel Ángel; Desco, Manuel

    2014-01-01

    Purpose The goal of this study was to compare the tumor uptake kinetics and diagnostic value of three 68Ga-DOTA-labeled somatostatin analogues (68Ga-DOTATOC, 68Ga-DOTANOC, and 68Ga-DOTATATE) using PET/CT in a murine model with subcutaneous meningioma xenografts. Methods The experiment was performed with 16 male NUDE NU/NU mice bearing xenografts of a human meningioma cell line (CH-157MN). 68Ga-DOTATOC, 68Ga-DOTANOC, and 68Ga-DOTATATE were produced in a FASTLab automated platform. Imaging was performed on an Argus small-animal PET/CT scanner. The SUVmax of the liver and muscle, and the tumor-to-liver (T/L) and tumor-to-muscle (T/M) SUV ratios were computed. Kinetic analysis was performed using Logan graphical analysis for a two-tissue reversible compartmental model, and the volume of distribution (Vt) was determined. Results Hepatic SUVmax and Vt were significantly higher with 68Ga-DOTANOC than with 68Ga-DOTATOC and 68Ga-DOTATATE. No significant differences between tracers were found for SUVmax in tumor or muscle. No differences were found in the T/L SUV ratio between 68Ga-DOTATATE and 68Ga-DOTATOC, both of which had a higher fraction than 68Ga-DOTANOC. The T/M SUV ratio was significantly higher with 68Ga-DOTATATE than with 68Ga-DOTATOC and 68Ga-DOTANOC. The Vt for tumor was higher with 68Ga-DOTATATE than with 68Ga-DOTANOC and relatively similar to that of 68Ga-DOTATOC. Conclusions This study demonstrates, for the first time, the ability of the three radiolabeled somatostatin analogues tested to image a human meningioma cell line. Although Vt was relatively similar with 68Ga-DOTATATE and 68Ga-DOTATOC, uptake was higher with 68Ga-DOTATATE in the tumor than with 68Ga-DOTANOC and 68Ga-DOTATOC, suggesting a higher diagnostic value of 68Ga-DOTATATE for detecting meningiomas. PMID:25369268

  11. Meningiomas: a comparative study of 68Ga-DOTATOC, 68Ga-DOTANOC and 68Ga-DOTATATE for molecular imaging in mice.

    Directory of Open Access Journals (Sweden)

    María Luisa Soto-Montenegro

    Full Text Available The goal of this study was to compare the tumor uptake kinetics and diagnostic value of three (68Ga-DOTA-labeled somatostatin analogues ((68Ga-DOTATOC, (68Ga-DOTANOC, and (68Ga-DOTATATE using PET/CT in a murine model with subcutaneous meningioma xenografts.The experiment was performed with 16 male NUDE NU/NU mice bearing xenografts of a human meningioma cell line (CH-157MN. (68Ga-DOTATOC, (68Ga-DOTANOC, and (68Ga-DOTATATE were produced in a FASTLab automated platform. Imaging was performed on an Argus small-animal PET/CT scanner. The SUVmax of the liver and muscle, and the tumor-to-liver (T/L and tumor-to-muscle (T/M SUV ratios were computed. Kinetic analysis was performed using Logan graphical analysis for a two-tissue reversible compartmental model, and the volume of distribution (Vt was determined.Hepatic SUVmax and Vt were significantly higher with (68Ga-DOTANOC than with (68Ga-DOTATOC and (68Ga-DOTATATE. No significant differences between tracers were found for SUVmax in tumor or muscle. No differences were found in the T/L SUV ratio between (68Ga-DOTATATE and (68Ga-DOTATOC, both of which had a higher fraction than (68Ga-DOTANOC. The T/M SUV ratio was significantly higher with (68Ga-DOTATATE than with (68Ga-DOTATOC and (68Ga-DOTANOC. The Vt for tumor was higher with (68Ga-DOTATATE than with (68Ga-DOTANOC and relatively similar to that of (68Ga-DOTATOC.This study demonstrates, for the first time, the ability of the three radiolabeled somatostatin analogues tested to image a human meningioma cell line. Although Vt was relatively similar with (68Ga-DOTATATE and (68Ga-DOTATOC, uptake was higher with (68Ga-DOTATATE in the tumor than with (68Ga-DOTANOC and (68Ga-DOTATOC, suggesting a higher diagnostic value of (68Ga-DOTATATE for detecting meningiomas.

  12. Diffusion-weighted and T2-weighted MR imaging for colorectal liver metastases detection in a rat model at 7 T: a comparative study using histological examination as reference

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Mathilde; Ronot, Maxime; Vilgrain, Valerie; Beers, Bernard E. van [University Paris Diderot, Sorbonne Paris Cite, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique- Hopitaux de Paris, Laboratory of Physiological and Molecular Imaging of the Abdomen (IPMA) and Department of Radiology, Clichy Cedex (France); Maggiori, Leon; Panis, Yves [University Paris Diderot, Sorbonne Paris Cite, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique-Hopitaux de Paris, Department of Colorectal Surgery, Clichy (France); Paradis, Valerie [University Paris Diderot, Sorbonne Paris Cite, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique-Hopitaux de Paris, Department of Pathology, Clichy (France)

    2013-08-15

    To compare diffusion-weighted (DW) and T2-weighted MR imaging in detecting colorectal liver metastases in a rat model, using histological examination as a reference method. Eighteen rats had four liver injections of colon cancer cells. MR examinations at 7 T included FSE-T2-weighted imaging and SE-DW MR imaging (b = 0, 20 and 150 s/mm{sup 2}) and were analysed by two independent readers. Histological examination was performed on 0.4-mm slices. McNemar's test was used to compare the sensitivities and the Wilcoxon matched pairs test to compare the average number of false-positives per rat. One hundred and sixty-six liver metastases were identified on histological examination. The sensitivity in detecting liver metastases was significantly higher on DW MR than on T2-weighted images (99/166 (60 %) (reader 1) and 92/166 (55 %) (reader 2) versus 77/166 (46 %), P {<=} 0.001), without an increase in false-positives per rat (P = 0.773/P = 0.850). After stratification according to metastasis diameter, DW MR imaging had a significantly higher sensitivity than T2-weighted imaging only for metastases with a diameter (0.6-1.2 mm) similar to that of the spatial resolution of MR imaging in the current study. This MR study with histological correlations shows the higher sensitivity of DW relative to T2-weighted imaging at 7 T for detecting liver metastases, especially small ones. (orig.)

  13. Comparison of a GPS needle-tracking system, multiplanar imaging and 2D imaging for real-time ultrasound-guided epidural anaesthesia: A randomized, comparative, observer-blinded study on phantoms.

    Science.gov (United States)

    Menacé, Cécilia; Choquet, Olivier; Abbal, Bertrand; Bringuier, Sophie; Capdevila, Xavier

    2017-04-01

    The real-time ultrasound-guided paramedian sagittal oblique approach for neuraxial blockade is technically demanding. Innovative technologies have been developed to improve nerve identification and the accuracy of needle placement. The aim of this study was to evaluate three types of ultrasound scans during ultrasound-guided epidural lumbar punctures in a spine phantom. Eleven sets of 20 ultrasound-guided epidural punctures were performed with 2D, GPS, and multiplanar ultrasound machines (660 punctures) on a spine phantom using an in-plane approach. For all punctures, execution time, number of attempts, bone contacts, and needle redirections were noted by an independent physician. Operator comfort and visibility of the needle (tip and shaft) were measured using a numerical scale. The use of GPS significantly decreased the number of punctures, needle repositionings, and bone contacts. Comfort of the physician was also significantly improved with the GPS system compared with the 2D and multiplanar systems. With the multiplanar system, the procedure was not facilitated and execution time was longer compared with 2D imaging after Bonferroni correction but interaction between the type of ultrasound system and mean execution time was not significant in a linear mixed model. There were no significant differences regarding needle tip and shaft visibility between the systems. Multiplanar and GPS needle-tracking systems do not reduce execution time compared with 2D imaging using a real-time ultrasound-guided paramedian sagittal oblique approach in spine phantoms. The GPS needle-tracking system can improve performance in terms of operator comfort, the number of attempts, needle redirections and bone contacts. Copyright © 2016 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

  14. Encoding and recall of finger sequences in experienced pianists compared with musically naïve controls: a combined behavioral and functional imaging study.

    Science.gov (United States)

    Pau, S; Jahn, G; Sakreida, K; Domin, M; Lotze, M

    2013-01-01

    Long-term intensive sensorimotor training alters functional representation of the motor and sensory system and might even result in structural changes. However, there is not much knowledge about how previous training impacts learning transfer and functional representation. We tested 14 amateur pianists and 15 musically naïve participants in a short-term finger sequence training procedure, differing considerably from piano playing and measured associated functional representation with functional magnetic resonance imaging. The conditions consisted of encoding a finger sequence indicated by hand symbols ("sequence encoding") and subsequently replaying the sequence from memory, both with and without auditory feedback ("sequence retrieval"). Piano players activated motor areas and the mirror neuron system more strongly than musically naïve participants during encoding. When retrieving the sequence, musically naïve participants showed higher activation in similar brain areas. Thus, retrieval activations of naïve participants were comparable to encoding activations of piano players, who during retrieval performed the sequences more accurately despite lower motor activations. Interestingly, both groups showed primary auditory activation even during sequence retrieval without auditory feedback, supporting previous reports about coactivation of the auditory cortex after learned association with motor performance. When playing with auditory feedback, only pianists lateralized to the left auditory cortex. During encoding activation in left primary somatosensory cortex in the height of the finger representations had a predictive value for increased motor performance later on (error rates). Contrarily, decreased performance was associated with increased visual cortex activation during encoding. Our study extends previous reports about training transfer of motor knowledge resulting in superior training effects in musicians. Performance increase went along with activity in

  15. Comparative analysis of different methods for image enhancement

    Institute of Scientific and Technical Information of China (English)

    吴笑峰; 胡仕刚; 赵瑾; 李志明; 李劲; 唐志军; 席在芳

    2014-01-01

    Image enhancement technology plays a very important role to improve image quality in image processing. By enhancing some information and restraining other information selectively, it can improve image visual effect. The objective of this work is to implement the image enhancement to gray scale images using different techniques. After the fundamental methods of image enhancement processing are demonstrated, image enhancement algorithms based on space and frequency domains are systematically investigated and compared. The advantage and defect of the above-mentioned algorithms are analyzed. The algorithms of wavelet based image enhancement are also deduced and generalized. Wavelet transform modulus maxima (WTMM) is a method for detecting the fractal dimension of a signal, it is well used for image enhancement. The image techniques are compared by using the mean (μ), standard deviation (s), mean square error (MSE) and PSNR (peak signal to noise ratio). A group of experimental results demonstrate that the image enhancement algorithm based on wavelet transform is effective for image de-noising and enhancement. Wavelet transform modulus maxima method is one of the best methods for image enhancement.

  16. Comparative Study of Fluorodeoxyglucose Positron Emission Tomography and Magnetic Resonance Imaging for the Detection of Spinal Bone Marrow Infiltration in Untreated Patients with Multiple Myeloma

    International Nuclear Information System (INIS)

    Hur, J.; Yoon, C.S.; Hoon Ryu, Y.; Yun, M.J.; Suh, J.S.

    2008-01-01

    Background: The presence and extent of osteolytic bone lesions in untreated patients with multiple myeloma are important factors in the staging of the disease, and the extent of bone lesions in multiple myeloma cases significantly influences decisions regarding therapy. Recently, fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) have been used to detect bone marrow involvement in patients with multiple myeloma. Purpose: To compare the efficacy of FDG-PET and MRI for the detection of bone marrow infiltration into the spine in untreated patients with multiple myeloma. Material and Methods: Twenty-two patients with multiple myeloma underwent both FDG-PET and spine MRI. The examined spinal regions by MRI included 21 thoracic and lumbar spines, one lumbar spine, and 12 cervical spines. The following imaging sequences were performed: T1-weighted spin-echo MRI with and without fat suppression, and T2-weighted spin-echo MRI in the sagittal plane. In the patients with bone marrow abnormalities, an additional contrast-enhanced T1-weighted spin-echo MR image and a fat-suppressed T1-weighted spin-echo MR image were obtained. Patients were divided into three groups on the basis of the criteria defined by Durie and Salmon: stage I (n=9), stage II (n=3), and stage III (n=10). The number and location of lesions detected in both FGD-PET and MRI were recorded, and the lesions were compared using the McNemar test. Bone marrow biopsy results, the patient's clinical examinations, and other imaging findings (MRI, FDG-PET, etc.) were used as references. Results: In stages I and II (37 lesions in 12 patients), FDG-PET and MRI detected lesions in 78% (29 of 37 lesions) and 86% (32 of 37 lesions), respectively. However, the difference between the abilities of FDG-PET and MRI to detect lesions was not statistically significant (P=0.317). In stage III (101 lesions in 10 patients), FDG-PET and MRI detected lesions in 80% (81 of 101 lesions) and 92

  17. Comparative Study of Fluorodeoxyglucose Positron Emission Tomography and Magnetic Resonance Imaging for the Detection of Spinal Bone Marrow Infiltration in Untreated Patients with Multiple Myeloma

    Energy Technology Data Exchange (ETDEWEB)

    Hur, J.; Yoon, C.S.; Hoon Ryu, Y.; Yun, M.J.; Suh, J.S. (Dept. of Diagnostic Radiology and Research Inst. of Radiological Science, and Dept. of Nuclear Medicine, Yonsei Univ. College of Medicine, Seoul (KR))

    2008-05-15

    Background: The presence and extent of osteolytic bone lesions in untreated patients with multiple myeloma are important factors in the staging of the disease, and the extent of bone lesions in multiple myeloma cases significantly influences decisions regarding therapy. Recently, fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) have been used to detect bone marrow involvement in patients with multiple myeloma. Purpose: To compare the efficacy of FDG-PET and MRI for the detection of bone marrow infiltration into the spine in untreated patients with multiple myeloma. Material and Methods: Twenty-two patients with multiple myeloma underwent both FDG-PET and spine MRI. The examined spinal regions by MRI included 21 thoracic and lumbar spines, one lumbar spine, and 12 cervical spines. The following imaging sequences were performed: T1-weighted spin-echo MRI with and without fat suppression, and T2-weighted spin-echo MRI in the sagittal plane. In the patients with bone marrow abnormalities, an additional contrast-enhanced T1-weighted spin-echo MR image and a fat-suppressed T1-weighted spin-echo MR image were obtained. Patients were divided into three groups on the basis of the criteria defined by Durie and Salmon: stage I (n=9), stage II (n=3), and stage III (n=10). The number and location of lesions detected in both FGD-PET and MRI were recorded, and the lesions were compared using the McNemar test. Bone marrow biopsy results, the patient's clinical examinations, and other imaging findings (MRI, FDG-PET, etc.) were used as references. Results: In stages I and II (37 lesions in 12 patients), FDG-PET and MRI detected lesions in 78% (29 of 37 lesions) and 86% (32 of 37 lesions), respectively. However, the difference between the abilities of FDG-PET and MRI to detect lesions was not statistically significant (P=0.317). In stage III (101 lesions in 10 patients), FDG-PET and MRI detected lesions in 80% (81 of 101 lesions) and

  18. Comparative study of reconstruction filters for cranio examinations of the Philips system and its influence on the quality of the tomographic image

    International Nuclear Information System (INIS)

    Silveira, V.C.; Kodlulovich, S.; Delduck, R.S.; Oliveira, L.C.G.

    2011-01-01

    The aim of this study was to evaluate different reconstruction algorithm (kernels) applied for head examinations. The research was carried out using 40-slice MDCT (Philips, Brilliance 40 CT scanner) and an ACR Phantoms to evaluate the image quality. The doses were estimated applying the coefficients obtained by IMPACT .The study showed that independently of the filter used the values of CT number have no change. The low contrast showed that the choice of correct filter might result a decrease of 9% of doses values. For special resolution, the sharp filter showed a better response for low m As. The noise value of image to certain filters smooth has no changed, even by reducing the m As values. (author)

  19. Comparative study of 99Tcm-ciprofloxacin scintigraphy, 18F-FDG PET and diffusion weighted imaging for detecting secondary infection associated with severe acute pancreatitis

    International Nuclear Information System (INIS)

    Wang Jianhua; Sun Gaofeng; Zhang Jian; Shao Chengwei; Pan Guixia; Peng Ye; Mao Juanli; Zheng Jianming; Zuo Changjing

    2013-01-01

    Objective: To compare the diagnostic values of 99 Tc m -ciprofloxacin SPECT, 18 F-FDG PET and MR diffusion weighted imaging (DWI) for detecting secondary infection associated with severe acute pancreatitis (SAP) in swine. Methods: Swine models were constructed and grouped, including control group (normal swine, n=6), non-infected SAP group (inoculated with inactivation Escherichia coli, n=6)and infected SAP group (inoculated with Escherichia coli, n=16). At 7 d after inoculation,a series of 99 Tc m ciprofloxacin SPECT, 18 F-FDG PET and MR DWI scans were performed. The imaging findings were visually evaluated and semi-quantitative analyzed. Lesion-background radioactive counts ratio (L/B), SUV max and the apparent diffusion coefficient (ADC) were calculated. The image results were compared with histopathological and bacteriological results, and the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were calculated. Bonferroni test, the least significant difference t test and χ 2 test were used for statistical data analysis. Results: (1) The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 99 Tc m -ciprofloxacin SPECT via visual analysis were 93.8% (15/16), 5/6, 90.9% (20/22), 93.8%(15/16) and 5/6, whereas 81.2% (13/16), 2/6, 68.2% (15/22), 76.5%(13/17) and 2/5 for 18 F-FDG PET, and 15.4% (2/13), 5/6, 36.8%(7/19), 2/3 and 31.3% (5/16) for MRI DWI respectively. Both 99 Tc m -ciprofloxacin SPECT and 18 F-FDG PET had higher sensitivities (both P>0.05), but the specificity of 18 F-FDG PET was lower. (2) 99 Tc m -ciprofloxacin imaging showed the changes of L/B for the infected SAP swine were significantly different from those of the non-infected and normal swine (F=95.66, P<0.001). 18 F-FDG PET early-phase images showed SUV max was not significantly different between infected SAP (2.61±1.07) and non-infected SAP (1.87±0.76) groups (P>0.05), but the SUV max of infected SAP group was

  20. Recent lung imaging studies

    International Nuclear Information System (INIS)

    Taplin, G.V.; Chopra, S.K.

    1976-01-01

    Radionuclide lung imaging procedures have been available for 11 years but only the perfusion examination has been used extensively and mainly for the diagnosis of pulmonary embolism (P.E.). Its ability to reveal localized ischemia makes it a valuable test of regional lung function as well as a useful diagnostic aid in P.E. Although it had been recognized for several years that chronic obstructive pulmonary disease (COPD) can cause lung perfusion defects which may simulate pulmonary embolism, relatively little use has been made of either the radioxenon or the radioaerosol inhalation lung imaging procedures until the last few years as a means of distinguishing P.E. from COPD. In this review emphasis is placed on our recent experience with both of these inhalation procedures in comparison with pulmonary function tests and roentgenography for the early detection of COPD in population studies. Equal emphasis is given to simultaneous aerosol ventilation-perfusion (V/P) imaging for a functional diagnosis of P.E. Two new developments in regional lung diffusion imaging, performed after the inhalation of radioactive gases and/or rapidly absorbed radioaerosols are described. The experimental basis for their potential clinical application in pulmonary embolism detection is presented

  1. Prospective study comparing three-dimensional computed tomography and magnetic resonance imaging for evaluating the renal vascular anatomy in potential living renal donors.

    Science.gov (United States)

    Bhatti, Aftab A; Chugtai, Aamir; Haslam, Philip; Talbot, David; Rix, David A; Soomro, Naeem A

    2005-11-01

    To prospectively compare the accuracy of multislice spiral computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) in evaluating the renal vascular anatomy in potential living renal donors. Thirty-one donors underwent multislice spiral CTA and gadolinium-enhanced MRA. In addition to axial images, multiplanar reconstruction and maximum intensity projections were used to display the renal vascular anatomy. Twenty-four donors had a left laparoscopic donor nephrectomy (LDN), whereas seven had right open donor nephrectomy (ODN); LDN was only considered if the renal vascular anatomy was favourable on the left. CTA and MRA images were analysed by two radiologists independently. The radiological and surgical findings were correlated after the surgery. CTA showed 33 arteries and 32 veins (100% sensitivity) whereas MRA showed 32 arteries and 31 veins (97% sensitivity). CTA detected all five accessory renal arteries whereas MRA only detected one. CTA also identified all three accessory renal veins whereas MRA identified two. CTA had a sensitivity of 97% and 47% for left lumbar and left gonadal veins, whereas MRA had a sensitivity of 74% and 46%, respectively. Multislice spiral CTA with three-dimensional reconstruction was more accurate than MRA for both renal arterial and venous anatomy.

  2. Comparative analysis of Medicare spending for medical imaging: sustained dramatic slowdown compared with other services.

    Science.gov (United States)

    Lee, David W; Duszak, Richard; Hughes, Danny R

    2013-12-01

    The purpose of this study was to assess trends in Medicare spending growth for medical imaging relative to other services and the Deficit Reduction Act (DRA). We calculated per-beneficiary Part B Medicare medical imaging expenditures for three-digit Berenson-Eggers Type of Service (BETOS) categories using Physician Supplier Procedure Summary Master Files for 32 million beneficiaries from 2000 to 2011. We adjusted BETOS categories to address changes in coding and payment policy and excluded categories with 2011 aggregate spending less than $500 million. We computed and ranked compound annual growth rates over three periods: pre-DRA (2000-2005), DRA transition period (2005-2007), and post-DRA (2007-2011). Forty-four modified BETOS categories fulfilled the inclusion criteria. Between 2000 and 2006, Medicare outlays for nonimaging services grew by 6.8% versus 12.0% for imaging services. In the ensuing 5 years, annual growth in spending for nonimaging continued at 3.6% versus a decline of 3.5% for imaging. Spending growth for all services during the pre-DRA, DRA, and post-DRA periods were 7.8%, 3.8%, and 2.9 compared with 15.0%, -3.4%, and -2.2% for advanced imaging services. Advanced imaging was among the fastest growing categories of Medicare services in the early 2000s but was in the bottom 2% of spending categories in 2011. Between 2007 and 2011, the fastest growing service categories were evaluation and management services with other specialists (29.1%), nursing home visits (11.2%), anesthesia (9.1%), and other ambulatory procedures (9.0%). Slowing volume growth and massive Medicare payment cuts have left medical imaging near the bottom of all service categories contributing to growth in Medicare spending.

  3. Low-field MR imaging of the spine. A comparative study of a traditional and a new, completely balanced gradient-echo sequence

    International Nuclear Information System (INIS)

    Drejer, J.; Thomsen, H.S.; Tanttu, J.

    1995-01-01

    49 patients underwent 53 examinations with both a traditional T1-weighted gradient-echo (PS) sequence and a new completely balanced steady-state 3-D (CBASS3D) sequence; 20 examinations included the cervical spine, 8 the thoracic spine and 25 the lumbar spine. All 106 examinations were reviewed twice regarding visibility of selected structures in the spinal region and diagnostic usefulness. The CBASS3D sequence delineated the medulla, nerve roots, CSF, the intervertebral discs and the posterior longitudinal ligament significantly better than the PS sequence. Disc hernia was also better visualised (p<0.01). There were significantly more artefacts on images obtained with the CBASS3D sequence, but they were usually outside the region of interest and occurred less frequently over time due to increased experience of the staff. Both reviewers found the diagnostic usefulness of CBASS3D to be superior compared to that of PS and excellent for diagnostic purposes. (orig./MG)

  4. Low-field MR imaging of the spine. A comparative study of a traditional and a new, completely balanced gradient-echo sequence

    Energy Technology Data Exchange (ETDEWEB)

    Drejer, J. [Dept. of Diagnostic Radiology, Herlev Hospital, Univ. Copenhagen (Denmark); Thomsen, H.S. [Dept. of Diagnostic Radiology, Herlev Hospital, Univ. Copenhagen (Denmark); Tanttu, J. [Picker Nordstar, Helsinki (Finland)

    1995-09-01

    49 patients underwent 53 examinations with both a traditional T1-weighted gradient-echo (PS) sequence and a new completely balanced steady-state 3-D (CBASS3D) sequence; 20 examinations included the cervical spine, 8 the thoracic spine and 25 the lumbar spine. All 106 examinations were reviewed twice regarding visibility of selected structures in the spinal region and diagnostic usefulness. The CBASS3D sequence delineated the medulla, nerve roots, CSF, the intervertebral discs and the posterior longitudinal ligament significantly better than the PS sequence. Disc hernia was also better visualised (p<0.01). There were significantly more artefacts on images obtained with the CBASS3D sequence, but they were usually outside the region of interest and occurred less frequently over time due to increased experience of the staff. Both reviewers found the diagnostic usefulness of CBASS3D to be superior compared to that of PS and excellent for diagnostic purposes. (orig./MG).

  5. Comparing hardcopy and softcopy results in the study of the impact of workflow on perceived reproduction quality of fine art images

    Science.gov (United States)

    Farnand, Susan; Jiang, Jun; Frey, Franziska

    2011-01-01

    A project, supported by the Andrew W. Mellon Foundation, is currently underway to evaluate current practices in fine art image reproduction, determine the image quality generally achievable, and establish a suggested framework for art image interchange. To determine the image quality currently being achieved, experimentation has been conducted in which a set of objective targets and pieces of artwork in various media were imaged by participating museums and other cultural heritage institutions. Prints and images for display made from the delivered image files at the Rochester Institute of Technology were used as stimuli in psychometric testing in which observers were asked to evaluate the prints as reproductions of the original artwork and as stand alone images. The results indicated that there were limited differences between assessments made using displayed images relative to printed reproductions. Further, the differences between rankings made with and without the original artwork present were much smaller than expected.

  6. Signal intensity change on unenhanced T1-weighted images in dentate nucleus and globus pallidus after multiple administrations of gadoxetate disodium: an intraindividual comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Giorgio; Minotti, Marta; De Piano, Francesca [Universita degli Studi di Milano, Postgraduation School in Radiodiagnostics, Milan (Italy); Preda, Lorenzo [Universita degli Studi di Pavia, Department of Clinical-Surgical Diagnostic and Pediatric Sciences, Pavia (Italy); National Center of Oncological Hadrontherapy (CNAO Foundation), Division of Radiology, Pavia (Italy); Cocorocchio, Emilia; Ferrucci, Pier Francesco [European Institute of Oncology, Melanoma and Sarcoma Medical Oncology Division, Milan (Italy); Raimondi, Sara [European Institute of Oncology, Division of Epidemiology and Biostatistics, Milan (Italy); Giannitto, Caterina; Petralia, Giuseppe [European Institute of Oncology, Division of Radiology, Milan (Italy); Bellomi, Massimo [European Institute of Oncology, Division of Radiology, Milan (Italy); Universita degli Studi di Milano, Oncology and Haematology/Oncology Department, Milan (Italy)

    2017-10-15

    To investigate whether there is an increased signal intensity (SI) of dentate nucleus (DN) and globus pallidus (GP) on unenhanced T1-weighted magnetic resonance imaging (MRI), in patients who had undergone multiple administrations of gadoxetate disodium. We retrospectively included stage III melanoma patients, who had been previously enrolled in a trial of adjuvant therapy and who had undergone whole-body contrast-enhanced MRIs with gadoxetate disodium every three months for their follow-up. The SI ratios of DN-to-pons and GP-to-thalamus on unenhanced T1-weighted images were calculated. The difference in SI ratios between the first and the last MRI examinations was assessed and a linear mixed model was performed to detect how SI ratios varied with the number of administrations. Eighteen patients were included in our study. The number of gadoxetate disodium administrations ranged from 2 to 18. Paired t-test did not show any significant difference in DN-to-pons (p=0.21) and GP-to-thalamus (p=0.09) SI ratios by the end of the study. DN-to-pons SI ratio and GP-to-thalamus SI ratio did not significantly increase with increasing the number of administrations (p=0.14 and p=0.06, respectively). Multiple administrations of gadoxetate disodium are not associated with increased SI in DN and GP in the brain. (orig.)

  7. Postoperative satisfaction and the patient's body image, life satisfaction, and self-esteem: a retrospective study comparing adolescent girls and boys after cosmetic surgery.

    Science.gov (United States)

    Kamburoğlu, Haldun O; Ozgür, Figen

    2007-01-01

    Cosmetic surgery procedures are more complex for adolescents than for adults because there are more factors affecting patient satisfaction, especially psychological factors. This study was designed to find answers to four main questions: (1) whether postoperative satisfaction rates differ statistically between males and females, (2) whether postoperative satisfaction correlates significantly with the self-esteem, body image, life satisfaction trilogy, (3) what the postoperative patient satisfaction and cosmetic procedure rates are among adolescents by years, and (4) whether a statistically significant relationship exists between postoperative satisfaction and a willingness of adolescents to undergo another cosmetic surgery. The study enrolled 86 of 165 patients who underwent surgery between January 2001 and June 2005. A simple poll consisting of 12 simple questions was used to collect data. No statistically significant difference was found in postoperative satisfaction rates between males and females. The findings show that postoperative satisfaction is significantly related to self-esteem, body image, and life satisfaction. The patient satisfaction rate was 93.83%, and there was no increase in adolescent cosmetic surgery rates over the years. Adolescents are good candidates for cosmetic surgery, but patients must be evaluated carefully. Any suspicion about a patient's psychological status must result in a psychiatric consultation.

  8. Comparative occupational radiation exposure between fixed and mobile imaging systems.

    Science.gov (United States)

    Kendrick, Daniel E; Miller, Claire P; Moorehead, Pamela A; Kim, Ann H; Baele, Henry R; Wong, Virginia L; Jordan, David W; Kashyap, Vikram S

    2016-01-01

    Endovascular intervention exposes surgical staff to scattered radiation, which varies according to procedure and imaging equipment. The purpose of this study was to determine differences in occupational exposure between procedures performed with fixed imaging (FI) in an endovascular suite compared with conventional mobile imaging (MI) in a standard operating room. A series of 116 endovascular cases were performed over a 4-month interval in a dedicated endovascular suite with FI and conventional operating room with MI. All cases were performed at a single institution and radiation dose was recorded using real-time dosimetry badges from Unfors RaySafe (Hopkinton, Mass). A dosimeter was mounted in each room to establish a radiation baseline. Staff dose was recorded using individual badges worn on the torso lead. Total mean air kerma (Kar; mGy, patient dose) and mean case dose (mSv, scattered radiation) were compared between rooms and across all staff positions for cases of varying complexity. Statistical analyses for all continuous variables were performed using t test and analysis of variance where appropriate. A total of 43 cases with MI and 73 cases with FI were performed by four vascular surgeons. Total mean Kar, and case dose were significantly higher with FI compared with MI. (mean ± standard error of the mean, 523 ± 49 mGy vs 98 ± 19 mGy; P < .00001; 0.77 ± 0.03 mSv vs 0.16 ± 0.08 mSv, P < .00001). Exposure for the primary surgeon and assistant was significantly higher with FI compared with MI. Mean exposure for all cases using either imaging modality, was significantly higher for the primary surgeon and assistant than for support staff (ie, nurse, radiology technologist) beyond 6 feet from the X-ray source, indicated according to one-way analysis of variance (MI: P < .00001; FI: P < .00001). Support staff exposure was negligible and did not differ between FI and MI. Room dose stratified according to case complexity (Kar) showed statistically significantly

  9. Comparative study of ultrasonography, computed tomography, magnetic resonance imaging, and magnetic resonance spectroscopy for the diagnosis for fatty liver in a rat model

    International Nuclear Information System (INIS)

    Noh, Hoon; Song, Xiao Li; Heo, Suk Hee; Kim, Jin Woong; Jeong, Yong Yeon; Kang, Heoung Keun; Shin, Sang Soo; Ahn, Kyu Youn

    2017-01-01

    To compare the accuracy of ultrasonography (US), single-energy CT (SECT), dual-energy CT (DECT), MR imaging (MRI), and MR spectroscopy (MRS) for detecting fatty liver in a rat model. Fatty liver was induced by 60% high-fat diet for 1, 2, 3, 4, or 5 weeks (3 rats per group, a total of 15 rats). The control group comprised of five rats fed 10% high-fat diet. US, SECT, DECT, MRI, and MRS of the liver were performed weekly. Histologic steatosis grade and intrahepatocelluar triglyceride level were determined histologically for the livers of sacrificed rats. Pearson correlation test was used to assess the correlation between examinations and standard reference levels. Receiver operating characteristic curves were constructed. Area under the curve (AUC), sensitivity, and specificity were calculated. US, SECT, DECT, MRI, and MRS were significantly correlated with histologic steatosis grade. The diagnostic performance of AUC, sensitivity, and specificity were 0.893, 80%, and 80% for US, 0.960, 80%, and 80% for SECT, 0.947, 100%, and 60% for DECT, 0.933, 93.3%, and 100% for MRI, and 0.960, 93.3%, and 100% for MRS. MRS showed the strongest correlation with histologic steatosis grade with the highest sensitivity and specificity for diagnosis of fatty liver compared to other modalities

  10. Comparative study of ultrasonography, computed tomography, magnetic resonance imaging, and magnetic resonance spectroscopy for the diagnosis for fatty liver in a rat model

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hoon; Song, Xiao Li; Heo, Suk Hee; Kim, Jin Woong; Jeong, Yong Yeon; Kang, Heoung Keun [Dept. of Radiology, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Shin, Sang Soo [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Ahn, Kyu Youn [Dept. of Anatomy, Chonnam National University Medical School, Gwangju (Korea, Republic of)

    2017-01-15

    To compare the accuracy of ultrasonography (US), single-energy CT (SECT), dual-energy CT (DECT), MR imaging (MRI), and MR spectroscopy (MRS) for detecting fatty liver in a rat model. Fatty liver was induced by 60% high-fat diet for 1, 2, 3, 4, or 5 weeks (3 rats per group, a total of 15 rats). The control group comprised of five rats fed 10% high-fat diet. US, SECT, DECT, MRI, and MRS of the liver were performed weekly. Histologic steatosis grade and intrahepatocelluar triglyceride level were determined histologically for the livers of sacrificed rats. Pearson correlation test was used to assess the correlation between examinations and standard reference levels. Receiver operating characteristic curves were constructed. Area under the curve (AUC), sensitivity, and specificity were calculated. US, SECT, DECT, MRI, and MRS were significantly correlated with histologic steatosis grade. The diagnostic performance of AUC, sensitivity, and specificity were 0.893, 80%, and 80% for US, 0.960, 80%, and 80% for SECT, 0.947, 100%, and 60% for DECT, 0.933, 93.3%, and 100% for MRI, and 0.960, 93.3%, and 100% for MRS. MRS showed the strongest correlation with histologic steatosis grade with the highest sensitivity and specificity for diagnosis of fatty liver compared to other modalities.

  11. Evaluation of vocal fold vibration with an assessment form for high-speed digital imaging: comparative study between healthy young and elderly subjects.

    Science.gov (United States)

    Yamauchi, Akihito; Imagawa, Hiroshi; Yokonishi, Hisayuki; Nito, Takaharu; Yamasoba, Tatsuya; Goto, Takao; Takano, Shingo; Sakakibara, Ken-Ichi; Tayama, Niro

    2012-11-01

    We conducted a prospective study with a subjective assessment form for high-speed digital imaging (HSDI) to elucidate the features of vocal fold vibrations in vocally healthy subjects and to clarify gender- and age-related differences. Healthy adult volunteers participated in this study. They were divided into young (aged 35 and younger) and elderly (aged 65 and older) groups, and the scores of an assessment form for HSDI characteristics elaborated at our institution were statistically analyzed. Twenty-six young subjects (males: 9, females: 17; mean age: 27 years) and 20 elderly subjects (males: 8, females: 12; mean age: 72 years) were assigned to our study. Posterior gap and posterior-to-anterior longitudinal phase difference were characteristic to young females, whereas in young males, mucosal wave, anterior-to-posterior longitudinal phase difference, and supraglottic hyperactivity were frequent. In elderly males, axis shift, asymmetry, supraglottic hyperactivity, increased mucosal wave, lateral phase difference, and anterior-to-posterior longitudinal phase difference were frequent; and in elderly females, high incidence of lateral phase difference, atrophic change, anterior gap, and asymmetry were observed. The results show that the behaviors of vocal fold vibrations were diverse even in healthy subjects with no vocal complaints or history of laryngeal diseases, and hence, the diversity of vocal fold vibrations in normal subjects must be taken into account in evaluating vocal fold vibrations. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  12. Liver fibrosis detection and staging: a comparative study of T1ρ MR imaging and 2D real-time shear-wave elastography.

    Science.gov (United States)

    Li, Ruo-Kun; Ren, Xin-Pin; Yan, Fu-Hua; Qiang, Jin-Wei; Lin, Hui-Min; Tao Wang; Zhao, Hong-Fei; Chen, Wei-Bo

    2017-12-02

    To compare the results of T1ρ MR imaging and 2D real-time shear-wave elastography (SWE) for liver fibrosis detection and staging. Twenty-nine rabbit models of CCl 4 -induced liver fibrosis were established and six untreated rabbits served as controls. T1ρ MR imaging and 2D real-time SWE examination were performed at 2, 4, 6, 8, 10, and 12 weeks. T1ρ values and liver stiffness (LS) values were measured. Fibrosis was staged according to the METAVIR scoring system. Correlation test was performed among T1ρ values, LS values, and fibrosis stage. Receiver operating characteristic (ROC) analysis was performed for assessing diagnostic performance of T1ρ and SWE in detection of no fibrosis (F0), substantial fibrosis (≥ F2), severe fibrosis (≥ F3), and cirrhosis (F4). There was moderate positive correlation between fibrosis stage and T1ρ values (r = 0.566; 95% CI 0.291-0.754; P < 0.0001), and LS value (r = 0.726; 95% CI 0.521-0.851; P = 0.003). T1ρ values showed moderate positive correlations with LS values [r = 0.693; 95% confidence interval (CI) 0.472-0.832; P < 0.0001]. Areas Under ROC (AUROCs) were 0.861 (95% CI 0.705-0.953) for SWE and 0.856 (95% CI 0.698-0.950) for T1ρ (P = 0.940), 0.906 (95% CI 0.762-0.978) for SWE and 0.849 (95% CI 0.691-0.946) for T1ρ (P = 0.414), 0.870 (95% CI 0.716-0.958) for SWE and 0.799 (95% CI 0.632-0.913) for T1ρ (P = 0.422), and 0.846 (95% CI 0.687-0.944) for SWE and 0.692 (95% CI 0.517-0.835) for T1ρ (P = 0.137), when diagnosing liver fibrosis with ≥ F1, ≥ F2, ≥ F3, and F4, respectively. There was moderate positive correlation between inflammatory activity and T1ρ values (r = 0.520; 95% CI 0.158-0.807; P = 0.013). T1ρ imaging has potential for liver fibrosis detection and staging with good diagnostic capability similar to that of ultrasonography elastography.

  13. Correlation between the tissue Doppler, strain rate, strain imaging during the dobutamine infusion and coronary fractional flow reserve during catheterization: a comparative study.

    Science.gov (United States)

    Dagdelen, Sinan; Yuce, Murat; Emiroglu, Yunus; Ergelen, Mehmet; Pala, Selcuk; Tanalp, Ali Cevat; Izgi, Akin; Kirma, Cevat

    2005-06-22

    Coronary fractional flow reserve (FFR) as an invasive, and dobutamine stress echocardiography (DSE) as a noninvasive technique were used to detect critical coronary stenosis. This study was undertaken to assess correlation between these two techniques by using tissue Doppler, strain rate (SR), and strain imaging (S). In 17 patients (aged 54.9+/-12.6, 4 F), a total of 22 vessels were studied. On dobutamine stress echocardiography, baseline and peak systolic (Sm), early (Em) and late (Am) diastolic myocardial velocities, SR and S were recorded from parasternal view (mid-posterior segment) for radial and apical view (mid-septum) for longitudinal deformation. Then coronary FFR was performed by using intracoronary adenosine infusion, and the value of system were analyzed for longitudinal SR and S values, it had a mild correlation with SR (r = 0.47, p = 0.044) and a good correlation with S (r = 0.66, p = 0.002). The quantification of regional myocardial deformation by using DSE rather than the motion would be more appropriate in detecting the ischemic dysfunctional segment supplied by the critical coronary stenosis. Strain measurement during the dobutamine infusion may provide an information on the FFR results of the culprit vessel.

  14. Head CT: Image quality improvement of posterior fossa and radiation dose reduction with ASiR - comparative studies of CT head examinations

    International Nuclear Information System (INIS)

    Guzinski, Maciej; Waszczuk, Lukasz; Sasiadek, Marek J.

    2016-01-01

    To evaluate head CT protocol developed to improve visibility of the brainstem and cerebellum, lower bone-related artefacts in the posterior fossa and maintain patient radioprotection. A paired comparison of head CT performed without Adaptive Statistical Iterative Reconstruction (ASiR) and a clinically indicated follow-up with 40 % ASiR was acquired in one group of 55 patients. Patients were scanned in the axial mode with different scanner settings for the brain and the posterior fossa. Objective image quality analysis was performed with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality analysis was based on brain structure visibility and evaluation of the artefacts. We achieved 19 % reduction of total DLP and significantly better image quality of posterior fossa structures. SNR for white and grey matter in the cerebellum were 34 % to 36 % higher, respectively, CNR was improved by 142 % and subjective analyses were better for images with ASiR. When imaging parameters are set independently for the brain and the posterior fossa imaging, ASiR has a great potential to improve CT performance: image quality of the brainstem and cerebellum is improved, and radiation dose for the brain as well as total radiation dose are reduced. (orig.)

  15. Head CT: Image quality improvement of posterior fossa and radiation dose reduction with ASiR - comparative studies of CT head examinations

    Energy Technology Data Exchange (ETDEWEB)

    Guzinski, Maciej; Waszczuk, Lukasz; Sasiadek, Marek J. [Wroclaw Medical University, Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw (Poland)

    2016-10-15

    To evaluate head CT protocol developed to improve visibility of the brainstem and cerebellum, lower bone-related artefacts in the posterior fossa and maintain patient radioprotection. A paired comparison of head CT performed without Adaptive Statistical Iterative Reconstruction (ASiR) and a clinically indicated follow-up with 40 % ASiR was acquired in one group of 55 patients. Patients were scanned in the axial mode with different scanner settings for the brain and the posterior fossa. Objective image quality analysis was performed with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality analysis was based on brain structure visibility and evaluation of the artefacts. We achieved 19 % reduction of total DLP and significantly better image quality of posterior fossa structures. SNR for white and grey matter in the cerebellum were 34 % to 36 % higher, respectively, CNR was improved by 142 % and subjective analyses were better for images with ASiR. When imaging parameters are set independently for the brain and the posterior fossa imaging, ASiR has a great potential to improve CT performance: image quality of the brainstem and cerebellum is improved, and radiation dose for the brain as well as total radiation dose are reduced. (orig.)

  16. Head CT: Image quality improvement of posterior fossa and radiation dose reduction with ASiR - comparative studies of CT head examinations.

    Science.gov (United States)

    Guziński, Maciej; Waszczuk, Łukasz; Sąsiadek, Marek J

    2016-10-01

    To evaluate head CT protocol developed to improve visibility of the brainstem and cerebellum, lower bone-related artefacts in the posterior fossa and maintain patient radioprotection. A paired comparison of head CT performed without Adaptive Statistical Iterative Reconstruction (ASiR) and a clinically indicated follow-up with 40 % ASiR was acquired in one group of 55 patients. Patients were scanned in the axial mode with different scanner settings for the brain and the posterior fossa. Objective image quality analysis was performed with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality analysis was based on brain structure visibility and evaluation of the artefacts. We achieved 19 % reduction of total DLP and significantly better image quality of posterior fossa structures. SNR for white and grey matter in the cerebellum were 34 % to 36 % higher, respectively, CNR was improved by 142 % and subjective analyses were better for images with ASiR. When imaging parameters are set independently for the brain and the posterior fossa imaging, ASiR has a great potential to improve CT performance: image quality of the brainstem and cerebellum is improved, and radiation dose for the brain as well as total radiation dose are reduced. •With ASiR it is possible to lower radiation dose or improve image quality •Sequentional imaging allows setting scan parameters for brain and posterior-fossa independently •We improved visibility of brainstem structures and decreased radiation dose •Total radiation dose (DLP) was decreased by 19.

  17. Comparing Generative Adversarial Network Techniques for Image Creation and Modification

    NARCIS (Netherlands)

    Pieters, Mathijs; Wiering, Marco

    2018-01-01

    Generative adversarial networks (GANs) have demonstrated to be successful at generating realistic real-world images. In this paper we compare various GAN techniques, both supervised and unsupervised. The effects on training stability of different objective functions are compared. We add an encoder

  18. Imaging the Moho beneath Sedimentary Basins: A Comparative Study of Virtual Deep Seismic Sounding (VDSS) and P Wave Receiver Functions (PRF)

    Science.gov (United States)

    Liu, T.; Klemperer, S. L.; Yu, C.; Ning, J.

    2017-12-01

    In the past decades, P wave receiver functions (PRF) have been routinely used to image the Moho, although it is well known that PRFs are susceptible to contamination from sedimentary multiples. Recently, Virtual Deep Seismic Sounding (VDSS) emerged as a novel method to image the Moho. However, despite successful applications of VDSS on multiple datasets from different areas, how sedimentary basins affect the waveforms of post-critical SsPmp, the Moho reflection phase used in VDSS, is not widely understood. Here, motivated by a dataset collected in the Ordos plateau, which shows distinct effects of sedimentary basins on SsPmp and Pms waveforms, we use synthetic seismograms to study the effects of sedimentary basins on SsPmp and Pms, the phases used in VDSS and PRF respectively. The results show that when the sedimentary thickness is on the same order of magnitude as the dominant wavelength of the incident S wave, SsPmp amplitude decreases significantly with S velocity of the sedimentary layer, whereas increasing sedimentary thickness has little effect in SsPmp amplitude. Our explanation is that the low S velocity layer at the virtual source reduces the incident angle of S wave at the free surface, thus decreases the S-to-P reflection coefficient at the virtual source. In addition, transmission loss associated with the bottom of sedimentary basins also contributes to reducing SsPmp amplitude. This explains not only our observations from the Ordos plateau, but also observations from other areas where post-critical SsPmp is expected to be observable, but instead is too weak to be identified. As for Pms, we observe that increasing sedimentary thickness and decreasing sedimentary velocities both can cause interference between sedimentary multiples and Pms, rendering the Moho depths inferred from Pms arrival times unreliable. The reason is that although Pms amplitude does not vary with sedimentary thickness or velocities, as sedimentary velocities decrease and thickness

  19. Comparative study using Monte Carlo methods of the radiation detection efficiency of LSO, LuAP, GSO and YAP scintillators for use in positron emission imaging (PET)

    International Nuclear Information System (INIS)

    Nikolopoulos, Dimitrios; Kandarakis, Ioannis; Tsantilas, Xenophon; Valais, Ioannis; Cavouras, Dionisios; Louizi, Anna

    2006-01-01

    The radiation detection efficiency of four scintillators employed, or designed to be employed, in positron emission imaging (PET) was evaluated as a function of the crystal thickness by applying Monte Carlo Methods. The scintillators studied were the LuSiO 5 (LSO), LuAlO 3 (LuAP), Gd 2 SiO 5 (GSO) and the YAlO 3 (YAP). Crystal thicknesses ranged from 0 to 50 mm. The study was performed via a previously generated photon transport Monte Carlo code. All photon track and energy histories were recorded and the energy transferred or absorbed in the scintillator medium was calculated together with the energy redistributed and retransported as secondary characteristic fluorescence radiation. Various parameters were calculated e.g. the fraction of the incident photon energy absorbed, transmitted or redistributed as fluorescence radiation, the scatter to primary ratio, the photon and energy distribution within each scintillator block etc. As being most significant, the fraction of the incident photon energy absorbed was found to increase with increasing crystal thickness tending to form a plateau above the 30 mm thickness. For LSO, LuAP, GSO and YAP scintillators, respectively, this fraction had the value of 44.8, 36.9 and 45.7% at the 10 mm thickness and 96.4, 93.2 and 96.9% at the 50 mm thickness. Within the plateau area approximately (57-59)% (59-63)% (52-63)% and (58-61)% of this fraction was due to scattered and reabsorbed radiation for the LSO, GSO, YAP and LuAP scintillators, respectively. In all cases, a negligible fraction (<0.1%) of the absorbed energy was found to escape the crystal as fluorescence radiation

  20. Sonography compared with MR imaging in the evaluation of card tethering following myelomeningocele repair

    International Nuclear Information System (INIS)

    Newman, B.; Bowen, A.; Albright, L.

    1989-01-01

    This paper reports on MR imaging and videotaped US spine examinations to evaluate cord tethering were retrospectively compared in 12 children with prior myelomeningocele repair and correlated with clinical and surgical findings. Although US did not delineate normal or abnormal anatomy as well as MR imaging, both types of studies confirmed the presence of tethering in 10 patients. One child with a normal US examination and abnormal MR images had tethering confirmed surgically. A second child had a US study suggestive of tethering with equivocal MR images. Postoperative studies in eight patients correlated less well; US suggested persistent tethering in five patients and MR imaging indicated tethering in two

  1. Gallium and imaging studies

    International Nuclear Information System (INIS)

    Vogel, H.C.

    1982-01-01

    The indications for the use of 67 Gallium imaging studies of the lungs are discussed. In spite of localization of 67 Ga in a large variety of neoplastic and inflammatory tissues, there is only limited application of the lung study in the differential diagnosis of pulmonary diseases. The chest radiograph will continue to be the principal tool for evaluation of pulmonary diseases. The 67 Ga-citrate scan serves as a study complementary to the chest radiograph, as it indicates the localization, extent and degree of activity of lung disease with greater accuracy than radiography. Gallium-67 scanning may be used in the evaluation of patients with lymphoreticular neoplasms, especially Hodgkin-disease and malignant lymphoma both during initial staging and in evaluation of the response to therapy. The 67 Ga-citrate scan is useful in the pre-operative evaluation of patients with lung cancer. Hilar and mediastinal lymphadenopathy are accurately revealed. The lung study is non-invasive and complementary to mediastinoscopy by showing from which glands a biopsy might be taken. Unsuspected extrathoracic secondaries may be shown up, as well as pulmonary metastases from malignancies elsewhere, although the metastases must be at least 1,5 cm in size. The 67 Ga lung scan is valuable in the evaluation of pulmonary infiltrates of suspicious infective etiology, the differentiation between pulmonary infection and pneumonia in selected cases, follow-up of sarcoid patients on corticosteroid therapy, evaluation of inflammatory activity of idiopathic pulmonary fibrosis and the early detection of neo-plastic or inflammatory diseases before the chest radiograph reveals abnormality, e.g. in diffuse carcinomatosis or Pneumocystis carinii-infection. The sensitivity of tumors to radiation or chemotherapy may be shown

  2. Comparative evaluation of image quality in computed radiology systems using imaging plates with different usage time

    International Nuclear Information System (INIS)

    Lazzaro, M.V.; Luz, R.M. da; Capaverde, A.S.; Silva, A.M. Marques da

    2015-01-01

    Computed Radiology (CR) systems use imaging plates (IPs) for latent image acquisition. Taking into account the quality control (QC) of these systems, imaging plates usage time is undetermined. Different recommendations and publications on the subject suggest tests to evaluate these systems. The objective of this study is to compare the image quality of IPs of a CR system, in a mammography service, considering the usage time and consistency of assessments. 8 IPs were used divided into two groups: the first group included 4 IPs with 3 years of use (Group A); the second group consisted of 4 new IPs with no previous exposure (Group B). The tests used to assess the IP's quality were: Uniformity, Differential Signal to Noise Ratio (SDNR), Ghost Effect and Figure of Merit (FOM). Statistical results show that the proposed tests are shown efficient in assessing the conditions of image quality obtained in CR systems in mammography and can be used as determining factors for the replacement of IP's. Moreover, comparing the two sets of IP, results led to the replacement of all the set of IP’s with 3 years of use. This work demonstrates the importance of an efficient quality control, not only with regard to the quality of IP's used, but in the acquisition system as a whole. From this work, these tests will be conducted on an annual basis, already targeting as future work, monitoring the wear of IP's Group B and the creation of a baseline for analysis and future replacements. (author)

  3. [Comparative studies of face recognition].

    Science.gov (United States)

    Kawai, Nobuyuki

    2012-07-01

    Every human being is proficient in face recognition. However, the reason for and the manner in which humans have attained such an ability remain unknown. These questions can be best answered-through comparative studies of face recognition in non-human animals. Studies in both primates and non-primates show that not only primates, but also non-primates possess the ability to extract information from their conspecifics and from human experimenters. Neural specialization for face recognition is shared with mammals in distant taxa, suggesting that face recognition evolved earlier than the emergence of mammals. A recent study indicated that a social insect, the golden paper wasp, can distinguish their conspecific faces, whereas a closely related species, which has a less complex social lifestyle with just one queen ruling a nest of underlings, did not show strong face recognition for their conspecifics. Social complexity and the need to differentiate between one another likely led humans to evolve their face recognition abilities.

  4. Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging: multicenter study comparing MR and dual-phase spiral CT

    NARCIS (Netherlands)

    M. Oudkerk (Matthijs); C.G. Torres; B. Song; M. Konig; J. Grimm; J. Fernandez-Cuadrado; B. op de Beeck; M. Marquardt; P. van Dijk (Pieter); J.C. de Groot (Jan Cees)

    2002-01-01

    textabstractPURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were

  5. Gadolinium- and manganite-based contrast agents with fluorescent probes for both magnetic resonance and fluorescence imaging of pancreatic islets: a comparative study

    Czech Academy of Sciences Publication Activity Database

    Berková, Z.; Jirák, D.; Zacharovová, K.; Lukeš, I.; Kotková, Z.; Kotek, J.; Kačenka, M.; Kaman, Ondřej; Řehoř, I.; Hájek, M.; Saudek, F.

    2013-01-01

    Roč. 8, č. 4 (2013), s. 614-621 ISSN 1860-7179 Institutional support: RVO:68378271 Keywords : contrast agents * gadolinium * magnetic resonance imaging * manganite * pancreatic islet s Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.046, year: 2013

  6. Detection of myocardial ischemia by automated, motion-corrected, color-encoded perfusion maps compared with visual analysis of adenosine stress cardiovascular magnetic resonance imaging at 3 T: a pilot study.

    Science.gov (United States)

    Doesch, Christina; Papavassiliu, Theano; Michaely, Henrik J; Attenberger, Ulrike I; Glielmi, Christopher; Süselbeck, Tim; Fink, Christian; Borggrefe, Martin; Schoenberg, Stefan O

    2013-09-01

    The purpose of this study was to compare automated, motion-corrected, color-encoded (AMC) perfusion maps with qualitative visual analysis of adenosine stress cardiovascular magnetic resonance imaging for detection of flow-limiting stenoses. Myocardial perfusion measurements applying the standard adenosine stress imaging protocol and a saturation-recovery temporal generalized autocalibrating partially parallel acquisition (t-GRAPPA) turbo fast low angle shot (Turbo FLASH) magnetic resonance imaging sequence were performed in 25 patients using a 3.0-T MAGNETOM Skyra (Siemens Healthcare Sector, Erlangen, Germany). Perfusion studies were analyzed using AMC perfusion maps and qualitative visual analysis. Angiographically detected coronary artery (CA) stenoses greater than 75% or 50% or more with a myocardial perfusion reserve index less than 1.5 were considered as hemodynamically relevant. Diagnostic performance and time requirement for both methods were compared. Interobserver and intraobserver reliability were also assessed. A total of 29 CA stenoses were included in the analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detection of ischemia on a per-patient basis were comparable using the AMC perfusion maps compared to visual analysis. On a per-CA territory basis, the attribution of an ischemia to the respective vessel was facilitated using the AMC perfusion maps. Interobserver and intraobserver reliability were better for the AMC perfusion maps (concordance correlation coefficient, 0.94 and 0.93, respectively) compared to visual analysis (concordance correlation coefficient, 0.73 and 0.79, respectively). In addition, in comparison to visual analysis, the AMC perfusion maps were able to significantly reduce analysis time from 7.7 (3.1) to 3.2 (1.9) minutes (P < 0.0001). The AMC perfusion maps yielded a diagnostic performance on a per-patient and on a per-CA territory basis comparable with the visual analysis

  7. Image registration in gastric emptying studies

    International Nuclear Information System (INIS)

    Shuter, B.; Cooper, R.G.

    1998-01-01

    Full text: We have previously shown that image registration, based upon a two-dimensional cross-correlation (CC) of logarithmic Laplacian images (LLI), corrected motion in biliary studies in up to 90% of cases with minimal artifact. We have now applied the same technique to gastric emptying studies (GES). GES were acquired on an LFOV gamma camera over a two-hour period as 20-26 pairs of anterior-posterior frames (30 second duration and 64 x 64 matrix) for both solid and liquid components. All images were manually registered so that the solid contents of the stomach lay within an operator-drawn ROI. The anterior images of the solid component for 30 randomly selected patients were subjected to further image registration using CC of LLI, CC of raw images (Rl) (a common approach to image registration) and CC of Laplacian images (Ll). All images were aligned to the third image of the study, on which an ROI was drawn to outline the stomach. The number of images in which stomach counts appeared outside this ROI were tallied, in the original and all re-registered studies. Maximum displacements in X/Y position between images of studies registered by the LLI and Rl methods were also computed to directly compare positional accuracy. Stomachs partially exceeded the limits of the ROI in 27, 9, 53 and 54 frames (total of 710) in the original, LLI, Rl and Ll studies respectively. There were 4, 1, 6 and 7 studies with misregistered stomachs on more than 2 frames. Frames in seven Rl studies differed from the LLI studies in ) X/Y position by 3 pixels or more. Cross-correlation using LLI was the only method which improved upon the original manual registration. The Rl and Ll methods increased the number of misregistered frames. We conclude that in gastric emptying studies, as in biliary studies, object tracking by CC of LLI is the method of choice for image registration

  8. MRI with intraoral orthodontic appliance-a comparative in vitro and in vivo study of image artefacts at 1.5 T.

    Science.gov (United States)

    Zachriat, C; Asbach, P; Blankenstein, K I; Peroz, I; Blankenstein, F H

    2015-01-01

    We investigated artefacts caused from orthodontic appliances at 1.5-T MRI of the head and neck region and whether the image quality can be improved utilizing the artefact-minimizing sequence WARP. In vitro tests were performed by phantom measurements of different orthodontic devices applying different types of MR sequences [echoplanar imaging (EPI), turbo spin echo (TSE) and TSE-WARP, gradient echo (GRE)]. Two independent readers determined after calibration the level of artefacts. Subsequently, the interobserver agreement was calculated. The measurement of artefacts was based on the American Society for Testing Materials Standard F 2119-07. For in vivo imaging, one test person was scanned with an inserted multibracket appliance. The level of artefacts for 27 target regions was evaluated. In vitro: ceramic brackets and ferromagnetic steel brackets produced artefact radii up to 1.12 and 7.40 cm, respectively. WARP reduced these artefacts by an average of 32.7%. The Bland-Altman-Plot indicated that maximum measurement differences of 3 mm have to be expected with two calibrated observers. In vivo: the EPI sequence for brain imaging was not analysable. The TSE sequence of the brain did not demonstrate artefacts except for the nasal cavity. Conversely, the TSE sequence of the cervical spine revealed severe artefacts in the midface region. The GRE sequence appeared to be more susceptible to artefacts than did the TSE sequence. In vitro measurements allow an estimation of the in vivo artefact size. Orthodontic appliances may often remain intraorally when performing MRI. WARP showed a more significant effect in vitro than in vivo.

  9. MRI with intraoral orthodontic appliance—a comparative in vitro and in vivo study of image artefacts at 1.5 T

    Science.gov (United States)

    Zachriat, C; Asbach, P; Blankenstein, K I; Peroz, I

    2015-01-01

    Objectives: We investigated artefacts caused from orthodontic appliances at 1.5-T MRI of the head and neck region and whether the image quality can be improved utilizing the artefact-minimizing sequence WARP. Methods: In vitro tests were performed by phantom measurements of different orthodontic devices applying different types of MR sequences [echoplanar imaging (EPI), turbo spin echo (TSE) and TSE-WARP, gradient echo (GRE)]. Two independent readers determined after calibration the level of artefacts. Subsequently, the interobserver agreement was calculated. The measurement of artefacts was based on the American Society for Testing Materials Standard F 2119-07. For in vivo imaging, one test person was scanned with an inserted multibracket appliance. The level of artefacts for 27 target regions was evaluated. Results: In vitro: ceramic brackets and ferromagnetic steel brackets produced artefact radii up to 1.12 and 7.40 cm, respectively. WARP reduced these artefacts by an average of 32.7%. The Bland–Altman-Plot indicated that maximum measurement differences of 3 mm have to be expected with two calibrated observers. In vivo: the EPI sequence for brain imaging was not analysable. The TSE sequence of the brain did not demonstrate artefacts except for the nasal cavity. Conversely, the TSE sequence of the cervical spine revealed severe artefacts in the midface region. The GRE sequence appeared to be more susceptible to artefacts than did the TSE sequence. Conclusions: In vitro measurements allow an estimation of the in vivo artefact size. Orthodontic appliances may often remain intraorally when performing MRI. WARP showed a more significant effect in vitro than in vivo. PMID:25734243

  10. Image Transmission Studies

    Science.gov (United States)

    Blaine, G. James; Hill, Rexford L.; Rueter, Allen P.; Senol, Evren; Studt, James W.

    1988-06-01

    Radiological PACS image sizes and desired retrieval response times demand high-bandwidth communication networks. Local area network technology at speeds higher that 10 Megabits/second (IEEE 802.3) have not achieved standardization nor production volume. Our current PACS experiments are based on a three-level subnet approach using 10 Mb/s Ethernet channels. An Ethernet channel is shown to support image transfers at an average throughput of 3 Mb/s. Preliminary measurements and simulation results suggest that traffic from as many as two-to-three archives can be supported on the same channel.

  11. Image transmission studies

    International Nuclear Information System (INIS)

    Blaine, G.J.; Hill, R.L.; Rueter, A.P.; Senol, E.; Studt, J.W.

    1988-01-01

    This paper discusses radiological PACS image sizes and desired retrieval response time that demand high-bandwidth communication networks. Local area network technology at speeds higher that 10 Megabits/second (IEEE 802.3) have not achieved standardization nor production volume. The authors describe current PACS experiments based on a three-level subnet approach using 10 Mb/s Ethernet channels. An Ethernet channel is shown to support image transfers at an average throughput of 3 Mb/s. Preliminary measurements and simulation results suggest that traffic from as many as two-to-three archives can be supported on the same channel

  12. Automated image registration for FDOPA PET studies

    International Nuclear Information System (INIS)

    Kang-Ping Lin; Sung-Cheng Huang, Dan-Chu Yu; Melega, W.; Barrio, J.R.; Phelps, M.E.

    1996-01-01

    In this study, various image registration methods are investigated for their suitability for registration of L-6-[18F]-fluoro-DOPA (FDOPA) PET images. Five different optimization criteria including sum of absolute difference (SAD), mean square difference (MSD), cross-correlation coefficient (CC), standard deviation of pixel ratio (SDPR), and stochastic sign change (SSC) were implemented and Powell's algorithm was used to optimize the criteria. The optimization criteria were calculated either unidirectionally (i.e. only evaluating the criteria for comparing the resliced image 1 with the original image 2) or bidirectionally (i.e. averaging the criteria for comparing the resliced image 1 with the original image 2 and those for the sliced image 2 with the original image 1). Monkey FDOPA images taken at various known orientations were used to evaluate the accuracy of different methods. A set of human FDOPA dynamic images was used to investigate the ability of the methods for correcting subject movement. It was found that a large improvement in performance resulted when bidirectional rather than unidirectional criteria were used. Overall, the SAD, MSD and SDPR methods were found to be comparable in performance and were suitable for registering FDOPA images. The MSD method gave more adequate results for frame-to-frame image registration for correcting subject movement during a dynamic FDOPA study. The utility of the registration method is further demonstrated by registering FDOPA images in monkeys before and after amphetamine injection to reveal more clearly the changes in spatial distribution of FDOPA due to the drug intervention. (author)

  13. Comparative evaluation of RetCam vs. gonioscopy images in congenital glaucoma

    OpenAIRE

    Azad, Raj V; Chandra, Parijat; Chandra, Anuradha; Gupta, Aparna; Gupta, Viney; Sihota, Ramanjit

    2014-01-01

    Purpose: To compare clarity, exposure and quality of anterior chamber angle visualization in congenital glaucoma patients, using RetCam and indirect gonioscopy images. Design: Cross-sectional study Participants. Congenital glaucoma patients over age of 5 years. Materials and Methods: A prospective consecutive pilot study was done in congenital glaucoma patients who were older than 5 years. Methods used are indirect gonioscopy and RetCam imaging. Clarity of the image, extent of angle visible a...

  14. Comparative effects of Facebook and conventional media on body image dissatisfaction

    OpenAIRE

    Cohen, Rachel; Blaszczynski, Alex

    2015-01-01

    Background Appearance comparison has consistently been shown to engender body image dissatisfaction. To date, most studies have demonstrated this relationship between appearance comparison and body image dissatisfaction in the context of conventional media images depicting the thin-ideal. Social comparison theory posits that people are more likely to compare themselves to similar others. Since social media forums such as Facebook involve one?s peers, the current study aimed to determine wheth...

  15. Sex work: a comparative study.

    Science.gov (United States)

    McCarthy, Bill; Benoit, Cecilia; Jansson, Mikael

    2014-10-01

    Explanations of adult involvement in sex work typically adopt one of two approaches. One perspective highlights a variety of negative experiences in childhood and adolescence, including physical and sexual abuse, family instability, poverty, associations with "pimps" and other exploiters, homelessness, and drug use. An alternative account recognizes that some of these factors may be involved, but underscores the contribution of more immediate circumstances, such as current economic needs, human capital, and employment opportunities. Prior research offers a limited assessment of these contrasting claims: most studies have focused exclusively on people working in the sex industry and they have not assessed the independent effects of life course variables central to these two perspectives. We add to this literature with an analysis that drew on insights from life course and life-span development theories and considered the contributions of factors from childhood, adolescence, and adulthood. Our comparative approach examined predictors of employment in sex work relative to two other low-income service or care work occupations: food and beverage serving and barbering and hairstyling. Using data from a study of almost 600 workers from two cities, one in Canada and the other in the United States, we found that both immediate circumstances and negative experiences from early life are related to current sex work involvement: childhood poverty, abuse, and family instability were independently associated with adult sex work, as were limited education and employment experience, adult drug use, and marital status.

  16. Comparative imaging and biodistribution studies with an anti-CEA monoclonal antibody and its F(ab)2 and Fab fragments in mice with colon carcinoma xenografts

    International Nuclear Information System (INIS)

    Andrew, S.M.; Pimm, M.V.; Baldwin, R.W.; Perkins, A.C.

    1986-01-01

    An IgG1 mouse monoclonal antibody directed against CEA has been digested with papain to yield F(ab) 2 and Fab fragments. Following radioiodination, intact antibody and fragments showed specific binding to cells of a CEA-producing tumour, although the immune reactivities of the fragments were lower than that of intact antibody. Gamma scintigraphy of nude mice bearing CEA producing human tumour xenografts and injected with 131 I-labelled fragments showed earlier and superior imaging of tumours than did 131 I-intact antibody, and this was most marked with the Fab fragment. Sequential dissection analyses showed that this was due to earlier and higher tumour-to-blood ratios with fragments than with intact antibody, but in absolute terms the degree of localization of both fragment types was significantly lower than that of intact antibody. (orig.)

  17. Imaging hydrated microbial extracellular polymers: Comparative analysis by electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dohnalkova, A.C.; Marshall, M. J.; Arey, B. W.; Williams, K. H.; Buck, E. C.; Fredrickson, J. K.

    2011-01-01

    Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

  18. Comparative imaging features of brucellar and tuberculous spondylitis

    International Nuclear Information System (INIS)

    Sharif, H.S.; Aldeyan, O.; Clark, D.C.; Madkour, M.M.

    1987-01-01

    Images obtained with various modalities in 17 patients with Brucella spondylitis and 12 patients with tuberculous spondylitis were analyzed in order to identify distinguishing features. All patients underwent radiography, 21 underwent bone scintigraphy, and all underwent high-resolution CT and/or MR imaging. Characteristic findings in Brucella spondylitis included a predilection for the lumbar spine, bone destruction limited to the end-plates and associated with sclerosis, and disk space collapse (16 of 19) with disk vacuum phenomenon in eight and localized soft-tissue edema. MR imaging showed diffuse increased signal in vertebrae, disks, and adjacent soft tissues on long repetition time/long echo time studies (four patients). Tuberculosis spondylitis was characterized by a midthoracic predilection, diffuse vertebral destruction with gibbus deformity, severe disk collapse, and extensive paraspinal abscesses. MR imaging findings (three patients) were similar to but more severe than findings in Brucella spondylitis

  19. Neuromyelitis optica: a diffusional kurtosis imaging study.

    Science.gov (United States)

    Doring, T M; Lopes, F C R; Kubo, T T A; Tukamoto, G; Kimura, M C; Strecker, R M; Domingues, R C; Gasparetto, E L

    2014-12-01

    Conventional MR imaging typically yields normal images of the brain or indicates lesions in areas of high aquaporin expression in patients with neuromyelitis optica. Diffusional kurtosis imaging was applied in patients with neuromyelitis optica to determine whether this technique could detect alterations in diffusion and diffusional kurtosis parameters in normal-appearing white matter and to explore the relationship between diffusional kurtosis imaging and DTI parameters. Thirteen patients with neuromyelitis optica and 13 healthy controls underwent MR imaging of the brain with conventional and diffusional kurtosis imaging sequences. Tract-based spatial statistics and region-of-interest-based analyses were conducted to identify differences between patients with neuromyelitis optica and controls through conventional DTI and diffusional kurtosis imaging parameters. The parameters were correlated to determine the potential relationship between them. Compared with healthy controls, several diffusional kurtosis imaging and DTI parameters were altered in various fiber tracts of patients with neuromyelitis optica (P optica. We found a negative correlation between diffusional kurtosis imaging (radial kurtosis, axial kurtosis, mean kurtosis) and the corresponding DTI parameters (radial diffusivity, axial diffusivity, mean diffusivity). Positive correlations were found for radial kurtosis and mean kurtosis with fractional anisotropy. This study demonstrated differences in conventional diffusion and diffusional kurtosis parameters, especially radial kurtosis, in the normal-appearing white matter of patients with neuromyelitis optica compared with healthy controls. Larger studies of patients with neuromyelitis optica should be performed to assess the potential clinical impact of these findings. © 2014 by American Journal of Neuroradiology.

  20. A comparative study of planar, SPECT, x-ray CT and angiographic imaging in the detectability of space occupying lesion (SOL) of liver

    International Nuclear Information System (INIS)

    Manabe, Takao; Oda, Junro; Kamino, Toshio

    1986-01-01

    Planar, SPECT, X-CT, and angiography were compared in 47 patients with suspected SOL in the liver. SPECT had greater sensitivity and specificity in detecting SOLs than planar. Especially the detection of SOL less than 3 cm was improved, and the smallest SOL detected by SPECT was 1.0 cm in diameter. SPECT appears reliable procedure for screening SOLs in the liver. Compared with X-CT, SPECT had nearly equal sensitivity in detecting SOLs more than 3 cm, and X-CT had higher sensitivity in detecting SOLs less than 3 cm. But in some cases, for example isodensity SOL, SPECT could detect the SOL which was missed by X-CT. (author)

  1. Comparative study Beamnrc VS Pinnacle

    International Nuclear Information System (INIS)

    Moreno Reyes, J. C.; Macias Jaen, J.; Jimenez Ortega, E.

    2013-01-01

    Has been developed in JAVA a software application called JJGAMMA, capable of manipulating the environment BEAMNRC and Pinnacle output formats 3 , comfortable, fast and accurately. As particular application you can use to compare dose distributions (plans for treatments, checking fields for modeling and clinical accelerators Commissioner) using, as objective criteria, function or Gamma index. (Author)

  2. Paracetamol suppositories: a comparative study.

    Science.gov (United States)

    Cullen, S; Kenny, D; Ward, O C; Sabra, K

    1989-01-01

    Paracetamol suppositories in two different bases were given to children who had fever after operations. Plasma concentrations and the effect on temperature were compared. There was a significant correlation between peak plasma concentrations and maximum drop in temperature. A lipophilic base produced better results than a hydrophilic base. PMID:2817936

  3. Paracetamol suppositories: a comparative study.

    OpenAIRE

    Cullen, S; Kenny, D; Ward, O C; Sabra, K

    1989-01-01

    Paracetamol suppositories in two different bases were given to children who had fever after operations. Plasma concentrations and the effect on temperature were compared. There was a significant correlation between peak plasma concentrations and maximum drop in temperature. A lipophilic base produced better results than a hydrophilic base.

  4. Are Compassionate and Self-Image Goals Comparable across Cultures?

    Directory of Open Access Journals (Sweden)

    Kuncewicz Dariusz

    2015-12-01

    Full Text Available This study tested whether compassionate goals to support others and self-image goals to maintain and defend desired self-images: 1 are equivalent constructs across three cultures (U.S., Japan, Poland; 2 overlap with interdependent self-construal; and 3 predict relationships and growth measures similarly in each country. We re-analyzed data from American (n = 130 and Japanese (n = 203 students, reported in Niiya et al. (2013, along with new data from Poland (n = 246. Single and multiple group confirmatory analyses showed that the two-factor structure holds across the three cultures. Interdependence correlated with compassionate and self-image goals only in Japan. In all three samples, compassionate goals correlated with non-zero-sum belief, feeling close, growth-seeking, self-compassion, and learning from failures, whereas self-image goals correlated with defensive responses to conflicts and validation-seeking. Our results suggest that compassionate and self-image goals may serve similar functions in relationships and growth across cultures.

  5. Differentiation of medial or lateral temporal lobe epilepsy by F-18-fluorodeoxyglucose positron emission tomography: comparative study with magnetic resonance imaging in 113 surgically and pathologically proven patients

    International Nuclear Information System (INIS)

    Lee, Dong Soo; Lee, Sang Kun; Chang, Ki Hyun; Chung, Chun Kee; Choi, Ki Young; Chung, June Key; Lee, Myung Chul

    1999-01-01

    As mesial temporal lobe epilepsy (TLE) shows hypometabolism of medial and lateral temporal lobe, we investigated whether symmetric uptake of F-18-FDG in medial temporal lobes can differentiate mesial from lateral TLE. In 113 patients (83 mesial TLE, 30 lateral TLE) who underwent anterior temporal lobectomy and/or corticectomy with good surgical outcome, we performed F-18-FDG PET and compared F-18-FDG uptake of medial and lateral temporal lobes. All the patients with mesial TLE had hippocampal sclerosis except one congenital abnormal hippocampus. Patients with lateral TLE revealed cerebromalacia, microdysgenesis, arteriovenous malformation, old contusion, and cortical dysplasia. Sensitivity of F-18-FDG PET and MR for mesial TLE was 84% (70/83) and 73% (62/83), respectively. Sensitivity of F-18-FDG PET and MR for lateral TLE was 90% (27/30) and 66% (20/30), respectively. Twelve patients were normal on F-18-FDG PET. 101 patients had hypometabolism of lateral temporal lobe. Among 88 patients who showed hypometabolism of medial temporal lobe as well as lateral temporal lobe, 70 were mesial TLE patients and 18 were lateral TLE on pathologic examination. Positive predictive value of medial temporal hypometabolism for mesial TLE was 80%. Among 13 patients who showed hypometabolism of only lateral temporal lobe, 4 were mesial TLE and 9 were lateral TLE. Positive predictive value of hypometabolism of lateral temporal lobe for the diagnosis of lateral TLE was 69% (9/ 13). Normal MR findings stood against medial TLE, whose negative predictive value was 66%. Lateral temporal lobe epilepsy should be suspected when there is decreased F-18-FDG uptake in lateral temporal lobe with normal uptake in medial temporal lobe

  6. Impact of 4D-(18)FDG-PET/CT imaging on target volume delineation in SBRT patients with central versus peripheral lung tumors. Multi-reader comparative study.

    Science.gov (United States)

    Chirindel, Alin; Adebahr, Sonja; Schuster, Daniel; Schimek-Jasch, Tanja; Schanne, Daniel H; Nemer, Ursula; Mix, Michael; Meyer, Philipp; Grosu, Anca-Ligia; Brunner, Thomas; Nestle, Ursula

    2015-06-01

    Evaluation of the effect of co-registered 4D-(18)FDG-PET/CT for SBRT target delineation in patients with central versus peripheral lung tumors. Analysis of internal target volume (ITV) delineation of central and peripheral lung lesions in 21 SBRT-patients. Manual delineation was performed by 4 observers in 2 contouring phases: on respiratory gated 4DCT with diagnostic 3DPET available aside (CT-ITV) and on co-registered 4DPET/CT (PET/CT-ITV). Comparative analysis of volumes and inter-reader agreement. 11 cases of peripheral and 10 central lesions were evaluated. In peripheral lesions, average CT-ITV was 6.2 cm(3) and PET/CT-ITV 8.6 cm(3), resembling a mean change in hypothetical radius of 2 mm. For both CT-ITVs and PET/CT-ITVs inter reader agreement was good and unchanged (0.733 and 0.716; p=0.58). All PET/CT-ITVs stayed within the PTVs derived from CT-ITVs. In central lesions, average CT-ITVs were 42.1 cm(3), PET/CT-ITVs 44.2 cm(3), without significant overall volume changes. Inter-reader agreement improved significantly (0.665 and 0.750; p1 ml in average for all observers. The addition of co-registered 4DPET data to 4DCT based target volume delineation for SBRT of centrally located lung tumors increases the inter-observer agreement and may help to avoid geographic misses. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Benchmarked Library Websites Comparative Study

    KAUST Repository

    Ramli, Rindra M.; Tyhurst, Janis

    2015-01-01

    This presentation provides an analysis of services provided by the benchmarked library websites. The exploratory study includes comparison of these websites against a list of criterion and presents a list of services that are most commonly deployed by the selected websites. In addition to that, the investigators proposed a list of services that could be provided via the KAUST library website.

  8. Comparative effects of Facebook and conventional media on body image dissatisfaction.

    Science.gov (United States)

    Cohen, Rachel; Blaszczynski, Alex

    2015-01-01

    Appearance comparison has consistently been shown to engender body image dissatisfaction. To date, most studies have demonstrated this relationship between appearance comparison and body image dissatisfaction in the context of conventional media images depicting the thin-ideal. Social comparison theory posits that people are more likely to compare themselves to similar others. Since social media forums such as Facebook involve one's peers, the current study aimed to determine whether the relationship between appearance comparison and body image dissatisfaction would be stronger for those exposed to social media images, compared to conventional media images. A sample of 193 female first year university students were randomly allocated to view a series of either Facebook or conventional media thin-ideal images. Participants completed questionnaires assessing pre- and post- image exposure measures of thin-ideal internalisation, appearance comparison, self-esteem, Facebook use and eating disorder risk. Type of exposure was not found to moderate the relationship between appearance comparison and changes in body image dissatisfaction. When analysed according to exposure type, appearance comparison only significantly predicted body image dissatisfaction change for those exposed to Facebook, but not conventional media. Facebook use was found to predict higher baseline body image dissatisfaction and was associated with higher eating disorder risk. The findings suggest the importance of extending the body image dissatisfaction literature by taking into account emerging social media formats. It is recommended that interventions for body image dissatisfaction and eating disorders consider appearance comparison processes elicited by thin-ideal content on social media forums, such as Facebook, in addition to conventional media.

  9. Imaging study on acupuncture points

    Science.gov (United States)

    Yan, X. H.; Zhang, X. Y.; Liu, C. L.; Dang, R. S.; Ando, M.; Sugiyama, H.; Chen, H. S.; Ding, G. H.

    2009-09-01

    The topographic structures of acupuncture points were investigated by using the synchrotron radiation based Dark Field Image (DFI) method. Four following acupuncture points were studied: Sanyinjiao, Neiguan, Zusanli and Tianshu. We have found that at acupuncture point regions there exists the accumulation of micro-vessels. The images taken in the surrounding tissue out of the acupuncture points do not show such kind of structure. It is the first time to reveal directly the specific structure of acupuncture points by X-ray imaging.

  10. Imaging study on acupuncture points

    International Nuclear Information System (INIS)

    Yan, X H; Zhang, X Y; Liu, C L; Dang, R S; Ando, M; Sugiyama, H; Chen, H S; Ding, G H

    2009-01-01

    The topographic structures of acupuncture points were investigated by using the synchrotron radiation based Dark Field Image (DFI) method. Four following acupuncture points were studied: Sanyinjiao, Neiguan, Zusanli and Tianshu. We have found that at acupuncture point regions there exists the accumulation of micro-vessels. The images taken in the surrounding tissue out of the acupuncture points do not show such kind of structure. It is the first time to reveal directly the specific structure of acupuncture points by X-ray imaging.

  11. Quantitative measurement of hepatic fibrosis with gadoxetic acid-enhanced magnetic resonance imaging in patients with chronic hepatitis B infection: A comparative study on aspartate aminotransferase to platelet ratio index and fibrosis-4 index

    International Nuclear Information System (INIS)

    Lee, Guy Mok; Kim, Youe Ree; Cho, Eun Young; Lee, Young Hwan; Yoon, Kwon Ha; Ryu, Jong Hyun; Kim, Tae Hoon

    2017-01-01

    To quantitatively measure hepatic fibrosis on gadoxetic acid-enhanced magnetic resonance (MR) in chronic hepatitis B (CHB) patients and identify the correlations with aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) values. This study on gadoxetic acid-enhanced 3T MR imaging included 81 patients with CHB infection. To quantitatively measure hepatic fibrosis, MR images were analyzed with an aim to identify inhomogeneous signal intensities calculated from a coefficient of variation (CV) map in the liver parenchyma. We also carried out a comparative analysis between APRI and FIB-4 based on metaregression results. The diagnostic performance of the CV map was evaluated using a receiver-operating characteristic (ROC) curve. In the MR images, the mean CV values in control, groups I, II, and III based on APRI were 4.08 ± 0.92, 4.24 ± 0.80, 5.64 ± 1.11, and 5.73 ± 1.28, respectively (p < 0.001). In CHB patients grouped by FIB-4, the mean CV values of groups A, B, and C were 4.22 ± 0.95, 5.40 ± 1.19, and 5.71 ± 1.17, respectively (p < 0.001). The mean CV values correlated well with APRI (r = 0.392, p < 0.001) and FIB-4 (r = 0.294, p < 0.001). In significant fibrosis group, ROC curve analysis yielded an area under the curve of 0.875 using APRI and 0.831 using FIB-4 in HB, respectively. Gadoxetic acid-enhanced MR imaging for calculating a CV map showed moderate correlation with APRI and FIB-4 values and could be employed to quantitatively measure hepatic fibrosis in patients with CHB

  12. Quantitative measurement of hepatic fibrosis with gadoxetic acid-enhanced magnetic resonance imaging in patients with chronic hepatitis B infection: A comparative study on aspartate aminotransferase to platelet ratio index and fibrosis-4 index

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Guy Mok; Kim, Youe Ree; Cho, Eun Young; Lee, Young Hwan; Yoon, Kwon Ha [Wonkwang University School of Medicine, Iksan (Korea, Republic of); Ryu, Jong Hyun; Kim, Tae Hoon [Imaging Science Research Center, Wonkwang University, Iksan (Korea, Republic of)

    2017-06-15

    To quantitatively measure hepatic fibrosis on gadoxetic acid-enhanced magnetic resonance (MR) in chronic hepatitis B (CHB) patients and identify the correlations with aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) values. This study on gadoxetic acid-enhanced 3T MR imaging included 81 patients with CHB infection. To quantitatively measure hepatic fibrosis, MR images were analyzed with an aim to identify inhomogeneous signal intensities calculated from a coefficient of variation (CV) map in the liver parenchyma. We also carried out a comparative analysis between APRI and FIB-4 based on metaregression results. The diagnostic performance of the CV map was evaluated using a receiver-operating characteristic (ROC) curve. In the MR images, the mean CV values in control, groups I, II, and III based on APRI were 4.08 ± 0.92, 4.24 ± 0.80, 5.64 ± 1.11, and 5.73 ± 1.28, respectively (p < 0.001). In CHB patients grouped by FIB-4, the mean CV values of groups A, B, and C were 4.22 ± 0.95, 5.40 ± 1.19, and 5.71 ± 1.17, respectively (p < 0.001). The mean CV values correlated well with APRI (r = 0.392, p < 0.001) and FIB-4 (r = 0.294, p < 0.001). In significant fibrosis group, ROC curve analysis yielded an area under the curve of 0.875 using APRI and 0.831 using FIB-4 in HB, respectively. Gadoxetic acid-enhanced MR imaging for calculating a CV map showed moderate correlation with APRI and FIB-4 values and could be employed to quantitatively measure hepatic fibrosis in patients with CHB.

  13. COMPARATIVE STUDY ON CORPORATE GOVERNANCE

    Directory of Open Access Journals (Sweden)

    Gavrea Corina

    2011-12-01

    Full Text Available Corporate governance is a key element of today’s economic reality being more and more present in many countries around the world. This paper has two main objectives. The first one is to offer more insight into the concept of corporate governance by a thorough literature review and by presenting and analyzing a framework of corporate governance. The second objective of this paper is to investigate the corporate governance situation in three developing economies (Romania, Bulgaria and Hungary. The World Bank and the European Bank for Reconstruction and Development published a series of reports on corporate governance. The present study uses data from these reports in order to illustrate how these developing economies are dealing with corporate governance. Based on ROSC Reports a corporate governance score was calculated. As this score shows, there is room for improvement for all three developing economies. This study is important because it shows the differences in corporate governance among developing economies and the need to study these nations at the individual country level. Corporate governance has many benefits for developing economies. It helps developing economies to register sustainable growth rates, to increases investors’ confidence in the national economy, and to increase the ability of capital markets to mobilize savings.

  14. Positron imaging studies

    International Nuclear Information System (INIS)

    Budinger, T.F.; Ganz, E.; Moyer, B.R.; Yano, Y.; Mathis, C.A.; Friedland, R.P.

    1982-01-01

    Several methods for the noninvasive evaluation of the metabolism and blood perfusion of brain and heart are reviewed. Heart muscle perfusion can be followed by measuring the accumulation of rubidium-82 simultaneously with the measurement of the arterial input. Deoxyglucose labelled with fluorine-18 was used to study the role of insulin in deoxyglucose accumulation

  15. Comparative study of Butterfly valves

    International Nuclear Information System (INIS)

    Galmes Belmonte, F.B.

    1998-01-01

    This work tries to justify the hydrodynamic butterfly valves performance, using the EPRI tests, results carried out in laboratory and in situ. This justification will be possible if: - The valves to study are similar - Their performance is calculated using EPRI's methodology Looking for this objective, the elements of the present work are: 1. Brief EPRI butterfly valve description it wild provide the factors which are necessary to define the butterfly valves similarity. 2. EPRI tests description and range of validation against test data definition. 3. Description of the spanish butterfly analyzed valves, and comparison with the EPRI performance results, to prove that this valves are similar to the EPRI test valves. In this way, it will not be necessary to carry out particular dynamic tests on the spanish valves to describe their hydrodynamic performance. (Author)

  16. Comparing planar image quality of rotating slat and parallel hole collimation: influence of system modeling

    International Nuclear Information System (INIS)

    Holen, Roel van; Vandenberghe, Stefaan; Staelens, Steven; Lemahieu, Ignace

    2008-01-01

    The main remaining challenge for a gamma camera is to overcome the existing trade-off between collimator spatial resolution and system sensitivity. This problem, strongly limiting the performance of parallel hole collimated gamma cameras, can be overcome by applying new collimator designs such as rotating slat (RS) collimators which have a much higher photon collection efficiency. The drawback of a RS collimated gamma camera is that, even for obtaining planar images, image reconstruction is needed, resulting in noise accumulation. However, nowadays iterative reconstruction techniques with accurate system modeling can provide better image quality. Because the impact of this modeling on image quality differs from one system to another, an objective assessment of the image quality obtained with a RS collimator is needed in comparison to classical projection images obtained using a parallel hole (PH) collimator. In this paper, a comparative study of image quality, achieved with system modeling, is presented. RS data are reconstructed to planar images using maximum likelihood expectation maximization (MLEM) with an accurate Monte Carlo derived system matrix while PH projections are deconvolved using a Monte Carlo derived point-spread function. Contrast-to-noise characteristics are used to show image quality for cold and hot spots of varying size. Influence of the object size and contrast is investigated using the optimal contrast-to-noise ratio (CNR o ). For a typical phantom setup, results show that cold spot imaging is slightly better for a PH collimator. For hot spot imaging, the CNR o of the RS images is found to increase with increasing lesion diameter and lesion contrast while it decreases when background dimensions become larger. Only for very large background dimensions in combination with low contrast lesions, the use of a PH collimator could be beneficial for hot spot imaging. In all other cases, the RS collimator scores better. Finally, the simulation of a

  17. Magnetic resonance imaging of the cranial nerves in the posterior fossa: a comparative study of t2-weighted spin-echo sequences at 1.5 and 3.0 tesla.

    Science.gov (United States)

    Fischbach, F; Müller, M; Bruhn, H

    2008-04-01

    High-field magnetic resonance imaging (MRI) at 3.0 Tesla (T) is rapidly gaining clinical acceptance. Whether doubling of the field strength of 1.5T and the subsequent increase in signal-to-noise ratio (SNR) leads to a significant improvement of image quality is not automatically given. To evaluate the depiction of fine anatomic detail in the posterior fossa, focusing on brain nerves, on T2-weighted imaging, and to define the potential advantage of imaging at 3.0T versus 1.5T. In total, 10 brainstem nerve pairs of 12 volunteers were identified on T2-weighted MR images of 2- and 5-mm section thickness acquired at 1.5T and 3.0T. The MR images were compared for each subject at both field strengths by three independent readers who rated image quality according to depiction of anatomic detail and contrast by using a rating scale. In general, MR images at 3.0T were considered more conspicuous and less noisy than images at 1.5T. The SNR value measured was almost doubled. With respect to structural identification and contrast according to the rating scale, observer scores were significantly improved both for standard imaging with 5-mm sections and high-resolution imaging with 2-mm sections at 3.0T. Direct comparison revealed a significant increase for evaluated image quality criteria and the number of nerves detected. The comparison revealed a clear advantage in favor of T2-weighted MRI at 3.0T vs. 1.5T in depicting the roots and course of brain nerves in the posterior fossa.

  18. Comparative evaluation of RetCam vs. gonioscopy images in congenital glaucoma

    Directory of Open Access Journals (Sweden)

    Raj V Azad

    2014-01-01

    Full Text Available Purpose: To compare clarity, exposure and quality of anterior chamber angle visualization in congenital glaucoma patients, using RetCam and indirect gonioscopy images. Design: Cross-sectional study Participants. Congenital glaucoma patients over age of 5 years. Materials and Methods: A prospective consecutive pilot study was done in congenital glaucoma patients who were older than 5 years. Methods used are indirect gonioscopy and RetCam imaging. Clarity of the image, extent of angle visible and details of angle structures seen were graded for both methods, on digitally recorded images, in each eye, by two masked observers. Outcome Measures: Image clarity, interobserver agreement. Results: 40 eyes of 25 congenital glaucoma patients were studied. RetCam image had excellent clarity in 77.5% of patients versus 47.5% by gonioscopy. The extent of angle seen was similar by both methods. Agreement between RetCam and gonioscopy images regarding details of angle structures was 72.50% by observer 1 and 65.00% by observer 2. Conclusions: There was good agreement between RetCam and indirect gonioscopy images in detecting angle structures of congenital glaucoma patients. However, RetCam provided greater clarity, with better quality, and higher magnification images. RetCam can be a useful alternative to gonioscopy in infants and small children without the need for general anesthesia.

  19. Comparative evaluation of RetCam vs. gonioscopy images in congenital glaucoma.

    Science.gov (United States)

    Azad, Raj V; Chandra, Parijat; Chandra, Anuradha; Gupta, Aparna; Gupta, Viney; Sihota, Ramanjit

    2014-02-01

    To compare clarity, exposure and quality of anterior chamber angle visualization in congenital glaucoma patients, using RetCam and indirect gonioscopy images. Cross-sectional study Participants. Congenital glaucoma patients over age of 5 years. A prospective consecutive pilot study was done in congenital glaucoma patients who were older than 5 years. Methods used are indirect gonioscopy and RetCam imaging. Clarity of the image, extent of angle visible and details of angle structures seen were graded for both methods, on digitally recorded images, in each eye, by two masked observers. Image clarity, interobserver agreement. 40 eyes of 25 congenital glaucoma patients were studied. RetCam image had excellent clarity in 77.5% of patients versus 47.5% by gonioscopy. The extent of angle seen was similar by both methods. Agreement between RetCam and gonioscopy images regarding details of angle structures was 72.50% by observer 1 and 65.00% by observer 2. There was good agreement between RetCam and indirect gonioscopy images in detecting angle structures of congenital glaucoma patients. However, RetCam provided greater clarity, with better quality, and higher magnification images. RetCam can be a useful alternative to gonioscopy in infants and small children without the need for general anesthesia.

  20. MRI quality control: six imagers studied using eleven unified image quality parameters

    International Nuclear Information System (INIS)

    Ihalainen, T.; Sipilae, O.; Savolainen, S.

    2004-01-01

    Quality control of the magnetic resonance imagers of different vendors in the clinical environment is non-harmonised, and comparing the performance is difficult. The purpose of this study was to develop and apply a harmonised long-term quality control protocol for the six imagers in our organisation in order to assure that they fulfil the same basic image quality requirements. The same Eurospin phantom set and identical imaging parameters were used with each imager. Values of 11 comparable parameters describing the image quality were measured. Automatic image analysis software was developed to objectively analyse the images. The results proved that the imagers were operating at a performance level adequate for clinical imaging. Some deficiencies were detected in image uniformity and geometry. The automated analysis of the Eurospin phantom images was successful. The measurements were successfully repeated after 2 weeks on one imager and after half a year on all imagers. As an objective way of examining the image quality, this kind of comparable and objective quality control of different imagers is considered as an essential step towards harmonisation of the clinical MRI studies through a large hospital organisation. (orig.)

  1. Comparative analysis of imaging configurations and objectives for Fourier microscopy.

    Science.gov (United States)

    Kurvits, Jonathan A; Jiang, Mingming; Zia, Rashid

    2015-11-01

    Fourier microscopy is becoming an increasingly important tool for the analysis of optical nanostructures and quantum emitters. However, achieving quantitative Fourier space measurements requires a thorough understanding of the impact of aberrations introduced by optical microscopes that have been optimized for conventional real-space imaging. Here we present a detailed framework for analyzing the performance of microscope objectives for several common Fourier imaging configurations. To this end, we model objectives from Nikon, Olympus, and Zeiss using parameters that were inferred from patent literature and confirmed, where possible, by physical disassembly. We then examine the aberrations most relevant to Fourier microscopy, including the alignment tolerances of apodization factors for different objective classes, the effect of magnification on the modulation transfer function, and vignetting-induced reductions of the effective numerical aperture for wide-field measurements. Based on this analysis, we identify an optimal objective class and imaging configuration for Fourier microscopy. In addition, the Zemax files for the objectives and setups used in this analysis have been made publicly available as a resource for future studies.

  2. Design-related bias in estimates of accuracy when comparing imaging tests: examples from breast imaging research

    International Nuclear Information System (INIS)

    Houssami, Nehmat; Ciatto, Stefano

    2010-01-01

    This work highlights concepts on the potential for design-related factors to bias estimates of test accuracy in comparative imaging research. We chose two design factors, selection of eligible subjects and the reference standard, to examine the effect of design limitations on estimates of accuracy. Estimates of sensitivity in a study of the comparative accuracy of mammography and ultrasound differed according to how subjects were selected. Comparison of a new imaging test with an existing test should distinguish whether the new test is to be used as a replacement for, or as an adjunct to, the conventional test, to guide the method for subject selection. Quality of the reference standard, examined in a meta-analysis of preoperative breast MRI, varied across studies and was associated with estimates of incremental accuracy. Potential solutions to deal with the reference standard are outlined where an ideal reference standard may not be available in all subjects. These examples of breast imaging research demonstrate that design-related bias, when comparing a new imaging test with a conventional imaging test, may bias accuracy in a direction that favours the new test by overestimating the accuracy of the new test or by underestimating that of the conventional test. (orig.)

  3. Imaging characteristics of hepatocellular adenoma compared with pathologic findings

    International Nuclear Information System (INIS)

    Zhao Jing; Zhao Xinming; Ouyang Han; Huang Wenting; Zhou Chunwu

    2012-01-01

    Objective: To retrospectively compare CT and MR features of hepatocellular adenoma with pathologic findings. Methods: Twelve patients with histopathologically proved hepatocellular adenoma were classified on the basis of pathologic and genotype phenotype findings into four groups: steatotic type, cytological abnormality type, telangiectatic adenoma with inflammatory infiltrates type and atypical adenoma type. The CT and MR features of each type were reviewed retrospectively compared with the pathological results. Results: In this retrospective study, 12 patients were examined with CT (8 patients) and MR (8 patients). Among 12 patients, 4 patients showed a steatotic type. One patient showed hypo-density on the non-enhanced CT and 3 patients demonstrated hypo-density on all phases of the post-contrast scans. Two lesions showed iso-intense signal on the in-phase T 1 WI with signal dropout on the out-of-phase T 1 WI, and hypo-intense signal on the T 2 WI with fat suppression sequences. One lesion demonstrated moderate hypointense signal on all phases of the post-contrast MRI scans. Two patients with the telangiectatic adenoma inflammatory infiltrates type were found. One patient showed hypo-density on the non-enhanced CT scans and hyper-density on all phases of the post-contrast CT scans. One patient demonstrated iso-intense signal and the other hypo-intense signal on the T 1 WI, and both displayed moderate hyper-intense signal on the T 2 WI with fat suppression sequences and hyper-intense signal with gradual enhancement on all phases of post-contrast MR scans. There were 3 patients with a cytological abnormality type. One patient appeared hypo-density and 1 patient showed uniform iso-density on non-enhanced CT scans. All patients who had undergone contrast-enhanced CT scans were found to have hyper-density on the hepatic arterial-dominant phase and became slightly lower on the portal venous phase. On the delay phase the density reduced further. One mass showed iso

  4. Post-contrast T1-weighted sequences in pediatric abdominal imaging: comparative analysis of three different sequences and imaging approach

    Energy Technology Data Exchange (ETDEWEB)

    Roque, Andreia; Ramalho, Miguel; AlObaidy, Mamdoh; Heredia, Vasco; Burke, Lauren M.; De Campos, Rafael O.P.; Semelka, Richard C. [University of North Carolina at Chapel Hill, Department of Radiology, Chapel Hill, NC (United States)

    2014-10-15

    Post-contrast T1-weighted imaging is an essential component of a comprehensive pediatric abdominopelvic MR examination. However, consistent good image quality is challenging, as respiratory motion in sedated children can substantially degrade the image quality. To compare the image quality of three different post-contrast T1-weighted imaging techniques - standard three-dimensional gradient-echo (3-D-GRE), magnetization-prepared gradient-recall echo (MP-GRE) and 3-D-GRE with radial data sampling (radial 3-D-GRE) - acquired in pediatric patients younger than 5 years of age. Sixty consecutive exams performed in 51 patients (23 females, 28 males; mean age 2.5 ± 1.4 years) constituted the final study population. Thirty-nine scans were performed at 3 T and 21 scans were performed at 1.5 T. Two different reviewers independently and blindly qualitatively evaluated all sequences to determine image quality and extent of artifacts. MP-GRE and radial 3-D-GRE sequences had the least respiratory motion (P < 0.0001). Standard 3-D-GRE sequences displayed the lowest average score ratings in hepatic and pancreatic edge definition, hepatic vessel clarity and overall image quality. Radial 3-D-GRE sequences showed the highest scores ratings in overall image quality. Our preliminary results support the preference of fat-suppressed radial 3-D-GRE as the best post-contrast T1-weighted imaging approach for patients under the age of 5 years, when dynamic imaging is not essential. (orig.)

  5. Detection rates in pediatric diagnostic imaging: a picture archive and communication system compared with a web-based imaging system

    International Nuclear Information System (INIS)

    McDonald, L.; Cramer, B.; Barrett, B.

    2006-01-01

    This prospective study assesses whether there are differences in accuracy of interpretation of diagnostic images among users of a picture archive and communication system (PACS) diagnostic workstation, compared with a less costly Web-based imaging system on a personal computer (PC) with a high resolution monitor. One hundred consecutive pediatric chest or abdomen and skeletal X-rays were selected from hospital inpatient and outpatient studies over a 5-month interval. They were classified as normal (n = 32), obviously abnormal (n = 33), or having subtle abnormal findings (n = 35) by 2 senior radiologists who reached a consensus for each individual case. Subsequently, 5 raters with varying degrees of experience independently viewed and interpreted the cases as normal or abnormal. Raters viewed each image 1 month apart on a PACS and on the Web-based PC imaging system. There was no relation between accuracy of detection and the system used to evaluate X-ray images (P = 0.92). The total percentage of incorrect interpretations on the Web-based PC imaging system was 23.2%, compared with 23.6% on the PACS (P = 0.92). For all raters combined, the overall difference in proportion assessed incorrectly on the PACS, compared with the PC system, was not significant at 0.4% (95%CI, -3.5% to 4.3%). The high-resolution Web-based imaging system via PC is an adequate alternative to a PACS clinical workstation. Accordingly, the provision of a more extensive network of workstations throughout the hospital setting could have potentially significant cost savings. (author)

  6. Image and surgery-related costs comparing cone beam CT and panoramic imaging before removal of impacted mandibular third molars

    DEFF Research Database (Denmark)

    Petersen, Lars Bo; Olsen, Kim Rose; Christensen, Jennifer Heather

    2014-01-01

    resource utilization. Differences in resources used for surgical and post-surgical management were calculated for each patient. Results: Converted to monetary units, the total costs for panoramic imaging equalized (sic)49.29 and for CBCT examination (sic)184.44. Modifying effects on this outcome......Objectives: The aim of this prospective clinical study was to derive the absolute and relative costs of cone beam CT (CBCT) and panoramic imaging before removal of an impacted mandibular third molar. Furthermore, the study aimed to analyse the influence of different cost-setting scenarios...... on the outcome of the absolute and relative costs and the incremental costs related to surgery. Methods: A randomized clinical trial compared complications following surgical removal of a mandibular third molar, where the pre-operative diagnostic method had been panoramic imaging or CBCT. The resources implied...

  7. A functional magnetic resonance imaging study

    Indian Academy of Sciences (India)

    MADU

    systems and ultra fast imaging techniques, such as echo planar imaging (EPI ) ... is used to understand brain organization, assessing of neurological status, and ..... J C 1998 Functional MRI studies of motor recovery after stroke;. NeuroImage 7 ...

  8. Impact of model-based iterative reconstruction on low-contrast lesion detection and image quality in abdominal CT: a 12-reader-based comparative phantom study with filtered back projection at different tube voltages

    Energy Technology Data Exchange (ETDEWEB)

    Euler, Andre; Stieltjes, Bram; Eichenberger, Reto; Reisinger, Clemens; Hirschmann, Anna; Zaehringer, Caroline; Kircher, Achim; Streif, Matthias; Bucher, Sabine; Buergler, David; D' Errico, Luigia; Kopp, Sebastien; Wilhelm, Markus [University Hospital Basel, Clinic of Radiology and Nuclear Medicine, Basel (Switzerland); Szucs-Farkas, Zsolt [Hospital Centre of Biel, Institute of Radiology, Biel (Switzerland); Schindera, Sebastian T. [University Hospital Basel, Clinic of Radiology and Nuclear Medicine, Basel (Switzerland); Cantonal Hospital Aarau, Institute of Radiology, Aarau (Switzerland)

    2017-12-15

    To evaluate the impact of model-based iterative reconstruction (MBIR) on image quality and low-contrast lesion detection compared with filtered back projection (FBP) in abdominal computed tomography (CT) of simulated medium and large patients at different tube voltages. A phantom with 45 hypoattenuating lesions was placed in two water containers and scanned at 70, 80, 100, and 120 kVp. The 120-kVp protocol served as reference, and the volume CT dose index (CTDI{sub vol}) was kept constant for all protocols. The datasets were reconstructed with MBIR and FBP. Image noise and contrast-to-noise-ratio (CNR) were assessed. Low-contrast lesion detectability was evaluated by 12 radiologists. MBIR decreased the image noise by 24% and 27%, and increased the CNR by 30% and 29% for the medium and large phantoms, respectively. Lower tube voltages increased the CNR by 58%, 46%, and 16% at 70, 80, and 100 kVp, respectively, compared with 120 kVp in the medium phantom and by 9%, 18% and 12% in the large phantom. No significant difference in lesion detection rate was observed (medium: 79-82%; large: 57-65%; P > 0.37). Although MBIR improved quantitative image quality compared with FBP, it did not result in increased low-contrast lesion detection in abdominal CT at different tube voltages in simulated medium and large patients. (orig.)

  9. Physics studies in Europe; a comparative study

    NARCIS (Netherlands)

    Steenstrup, S; dalle Rose, LFD; Jones, WG; Tugulea, L; van Steenwijk, FJ

    What are the differences and similarities between physics studies at different universities across Europe (here the definition of Europe is broad)? How much does a student have to work to obtain a degree in physics? Questions like those prompted EUPEN (European Physics Education Network) to make a

  10. Comparative study between computed radiography and conventional radiography

    International Nuclear Information System (INIS)

    Noorhazleena Azaman; Khairul Anuar Mohd Salleh; Sapizah Rahim; Shaharudin Sayuti; Arshad Yassin; Abdul Razak Hamzah

    2010-01-01

    In Industrial Radiography, there are many criteria that need to be considered based on established standards to accept or reject the radiographic film. For conventional radiography, we need to consider the optical density by using the densitometer when viewing the film on the viewer. But in the computed radiography (CR) we need to evaluate and performed the analysis from the quality of the digital image through grey value. There are many factors that affected the digital image quality. One of the factors which are affected to the digital image quality in the image processing is grey value that related to the contrast resolution. In this work, we performed grey value study measurement on digital radiography systems and compared it with exposed films in conventional radiography. The test sample is a steel step wedge. We found out the contrast resolution is higher in Computed Radiography compared with Conventional Radiography. (author)

  11. Comparative study of fixation density maps

    NARCIS (Netherlands)

    Engelke, U.; Liu, H.; Wang, Junle; Callet, Le P.; Heynderickx, I.E.J.; Zepernick, H.-J.; Maeder, A.

    2013-01-01

    Fixation density maps (FDM) created from eye tracking experiments are widely used in image processing applications. The FDM are assumed to be reliable ground truths of human visual attention and as such, one expects a high similarity between FDM created in different laboratories. So far, no studies

  12. Perinatal mortality: clinical value of postmortem magnetic resonance imaging compared with autopsy in routine obstetric practice

    NARCIS (Netherlands)

    Alderliesten, Marianne E.; Peringa, Jan; van der Hulst, Victor P. M.; Blaauwgeers, Hans L. G.; van Lith, Jan M. M.

    2003-01-01

    Objective To compare postmortem magnetic resonance imaging (MRI) with autopsy in perinatal deaths. To determine the acceptance and feasibility of postmortem perinatal MRI. Design Cohort study. Setting Large teaching hospital. Population Fetuses and neonates from 16 weeks gestational age until 28

  13. Comparing neutron and X-ray images from NIF implosions

    Directory of Open Access Journals (Sweden)

    Wilson D.C.

    2013-11-01

    Full Text Available Directly laser driven and X-radiation driven DT filled capsules differ in the relationship between neutron and X-ray images. Shot N110217, a directly driven DT-filled glass micro-balloon provided the first neutron images at the National Ignition Facility. As seen in implosions on the Omega laser, the neutron image can be enclosed inside time integrated X-ray images. HYDRA simulations show the X-ray image is dominated by emission from the hot glass shell while the neutron image arises from the DT fuel it encloses. In the absence of mix or jetting, X-ray images of a cryogenically layered THD fuel capsule should be dominated by emission from the hydrogen rather than the cooler plastic shell that is separated from the hot core by cold DT fuel. This cool, dense DT, invisible in X-ray emission, shows itself by scattering hot core neutrons. Germanium X-ray emission spectra and Ross pair filtered X-ray energy resolved images suggest that germanium doped plastic emits in the torus shaped hot spot, probably reducing the neutron yield.

  14. Effect of contrast material on image noise and radiation dose in adult chest computed tomography using automatic exposure control: A comparative study between 16-, 64- and 128-slice CT

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Jijo, E-mail: jijopaul1980@gmail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Goethe University, Department of Biophysics, Max von Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Schell, Boris, E-mail: boris.schell@googlemail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Kerl, J. Matthias, E-mail: matthias.kerl@gmai.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Maentele, Werner, E-mail: maentele@biophysik.uni-frankfurt.de [Goethe University, Department of Biophysics, Max von Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.de [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Bauer, Ralf W., E-mail: ralfwbauer@aol.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

    2011-08-15

    Purpose: To determine the difference in radiation dose between non-enhanced (NECT) and contrast-enhanced (CECT) chest CT examinations contributed by contrast material with different scanner generations with automatic exposure control (AEC). Methods and materials: Each 42 adult patients received a NECT and CECT of the chest in one session on a 16-, 64- or 128-slice CT scanner with the same scan protocol settings. However, AEC technology (Care Dose 4D, Siemens) underwent upgrades in each of the three scanner generations. DLP, CTDIvol and image noise were compared. Results: Although absolute differences in image noise were very small and ranged between 10 and 13 HU for NECT and CECT in median, the differences in image noise and dose (DLP: 16-slice:+2.8%; 64-slice:+3.9%; 128-slice:+5.6%) between NECT and CECT were statistically significant in all groups. Image noise and dose parameters were significantly lower in the most recent 128-slice CT generation for both NECT and CECT (DLP: 16-slice:+35.5-39.2%; 64-slice:+6.8-8.5%). Conclusion: The presence of contrast material lead to an increase in dose for chest examinations in three CT generations with AEC. Although image noise values were significantly higher for CECT, the absolute differences were in a range of 3 HU. This can be regarded as negligible, thus indicating that AEC is able to fulfill its purpose of maintaining image quality. However, technological developments lead to a significant reduction of dose and image noise with the latest CT generation.

  15. Measuring hepatic functional reserve using T1 mapping of Gd-EOB-DTPA enhanced 3T MR imaging: A preliminary study comparing with 99mTc GSA scintigraphy and signal intensity based parameters.

    Science.gov (United States)

    Nakagawa, Masataka; Namimoto, Tomohiro; Shimizu, Kie; Morita, Kosuke; Sakamoto, Fumi; Oda, Seitaro; Nakaura, Takeshi; Utsunomiya, Daisuke; Shiraishi, Shinya; Yamashita, Yasuyuki

    2017-07-01

    To determine the utility of liver T1-mapping on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance (MR) imaging for the measurement of liver functional reserve compared with the signal intensity (SI) based parameters, technetium-99m-galactosyl serum albumin ( 99m Tc-GSA) scintigraphy and indocyanine green (ICG) clearance. This retrospective study included 111 patients (Child-Pugh-A 90; -B 21) performed with both Gd-EOB-DTPA enhanced liver MR imaging and 99m Tc-GSA (76 patients with ICG). Receiver operating characteristic (ROC) curve analysis was performed to compare diagnostic performances of T1-relaxation-time parameters [pre-(T1pre) and post-contrast (T1hb) Gd-EOB-DTPA], SI based parameters [relative enhancement (RE), liver-to-muscle-ratio (LMR), liver-to-spleen-ratio (LSR)] and 99m Tc-GSA scintigraphy blood clearance index (HH15)] for Child-Pugh classification. Pearson's correlation was used for comparisons among T1-relaxation-time parameters, SI-based parameters, HH15 and ICG. A significant difference was obtained for Child-Pugh classification with T1hb, ΔT1, all SI based parameters and HH15. T1hb had the highest AUC followed by RE, LMR, LSR, ΔT1, HH15 and T1pre. The correlation coefficients with HH15 were T1pre 0.22, T1hb 0.53, ΔT1 -0.38 of T1 relaxation parameters; RE -0.44, LMR -0.45, LSR -0.43 of SI-based parameters. T1hb was highest for correlation with HH15. The correlation coefficients with ICG were T1pre 0.29, T1hb 0.64, ΔT1 -0.42 of T1 relaxation parameters; RE -0.50, LMR -0.61, LSR -0.58 of SI-based parameters; 0.64 of HH15. Both T1hb and HH15 were highest for correlation with ICG. T1 relaxation time at post-contrast of Gd-EOB-DTPA (T1hb) was strongly correlated with ICG clearance and moderately correlated HH15 with 99m Tc-GSA. T1hb has the potential to provide robust parameter of liver functional reserve. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Randomized, interventional, prospective, comparative study to ...

    African Journals Online (AJOL)

    Randomized, interventional, prospective, comparative study to evaluate the antihypertensive efficacy and tolerability of ramipril versus telmisartan in stage 1 hypertensive patients with diabetes mellitus.

  17. Tc-99m Methoxy Isobutyl Isonitrile (MIBI) scintimammography for detection of loco-regional recurrence of breast cancer: A comparative study of scintimammography, X-ray mammography and breast ultrasound imaging

    International Nuclear Information System (INIS)

    Usmani, S.; Niaz, K.; Ahmed, N.; Niyaz, K.; Khan, H.A.; Javed, A.; Mohannadi, S.A.; Huda, F.A.

    2007-01-01

    Breast cancer is the most common cancer among women and the second leading cause of death in women after lung cancer. Local recurrence rate is about 1-2% per year. It is important to find a sensitive and accurate diagnostic method for early detection of recurrent tumor for planning subsequent management. The principal aim of the present study was to assess the utility of Tc-99m MIBI scintimammography in the detection of loco-regional recurrence of breast cancer in comparison with the conventionally used methods like x-ray mammography and ultrasonography. A total number of 42 patients (Age: mean= 45.55 yrs; median = 43.5; range, 22-77 yrs) suspected to have loco-regional recurrence of breast cancer on the basis of clinical examination and/or conventional imaging procedures were included in this study. All patients were subjected to planar scintimammography (SMM), SPECT imaging of the breast, x-ray mammography and Ultrasound scanning. The results were correlated with the final diagnosis arrived at by fine needle aspiration cytology (FNAC), core biopsy or definite wide local excision. Sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV) and accuracy (ACC) of scintimammography in the diagnosis of recurrent disease were found to be 82.75, 92.3, 96.0, 70.58 and 85.71% respectively; compared to 45.83, 66.6, 78.57, 31.57, 51.51 for x-ray mammography and 65.51, 69.23, 82.6, 47.36, 66.66 for Ultrasonography. Scintimammography results were correlated with x-ray mammography and ultrasonography by applying Pearson correlation. No significant correlation was found between SMM and XMM (r=0.27) or SMM and US (r=0.23). Based on the results of this study it is concluded that SMM has better diagnostic accuracy than mammography and ultrasonography in the detection of loco-regional recurrence of breast cancer. (author)

  18. Discrimination of benign and malignant lymph nodes at 7.0T compared to 1.5T magnetic resonance imaging using ultrasmall particles of iron oxide: a feasibility preclinical study.

    Science.gov (United States)

    Kinner, Sonja; Maderwald, Stefan; Albert, Juliane; Parohl, Nina; Corot, Claire; Robert, Philippe; Baba, Hideo A; Barkhausen, Jörg

    2013-12-01

    To investigate the feasibility and performance of 7T magnetic resonance imaging compared to 1.5T imaging to discriminate benign (normal and inflammatory changed) from tumor-bearing lymph nodes in rabbits using ultrasmall particles of iron oxide (USPIO)-based contrast agents. Six New Zealand White rabbits were inoculated with either complete Freund's adjuvant cell suspension (n = 3) to induce reactively enlarged lymph nodes or with VX2 tumor cells to produce metastatic lymph nodes (n = 3). Image acquisition was performed before and 24 hours after bolus injection of an USPIO contrast agent at 1.5T and afterward at 7T using T1-weighted and T2*-weighted sequences. Sensitivities, specificities, and negative and positive predictive values for the detection of lymph node metastases were calculated for both field strengths with histopathology serving as reference standard. Sizes of lymph nodes with no, inflammatory, and malignant changes were compared using a Mann-Whitney U-test. All 24 lymph nodes were detected at 1.5T as well as at 7T. At 1.5T, sensitivity amounted to 0.67, while specificity reached a value of 1. At the higher field strength (7T), imaging was able to reach sensitivity and specificity values of 1. No statistical differences were detected concerning lymph node sizes. Magnetic resonance lymphography with USPIO contrast agents allows for differentiation of normal and reactively enlarged lymph nodes compared to metastatic nodes. First experiments at 7T show promising results compared to 1.5T, which have to be evaluated in further trials. Copyright © 2013. Published by Elsevier Inc.

  19. Low molecular weight dextran provides similar optical coherence tomography coronary imaging compared to radiographic contrast media.

    Science.gov (United States)

    Frick, Kyle; Michael, Tesfaldet T; Alomar, Mohammed; Mohammed, Atif; Rangan, Bavana V; Abdullah, Shuaib; Grodin, Jerrold; Hastings, Jeffrey L; Banerjee, Subhash; Brilakis, Emmanouil S

    2014-11-01

    Optical coherence tomography (OCT) coronary imaging requires displacement of red blood cells from the vessel lumen. This is usually accomplished using radiographic contrast. Low molecular weight dextran has low cost and is safe in low volumes. In the present study, we compared dextran with contrast for coronary OCT imaging. Fifty-one vessels in 26 patients were sequentially imaged using manual injection of radiographic contrast (iodixanol) and dextran. OCT images were analyzed at 1 mm intervals to determine the image clarity (defined as a visible lumen border > 270°) and to measure the lumen area and lumen diameter. To correct for the refractive index of dextran, the dextran area measurements were multiplied by 1.117 and the dextran length measurements were multiplied by 1.057. A total of 3,418 cross-sections (1,709 with contrast and 1,709 with dextran) were analyzed. There were no complications related to OCT imaging or to contrast or dextran administration. Clear image segments were observed in 97.0% vs. 96.7% of the cross-sections obtained with contrast and dextran, respectively (P = 0.45). The mean lumen areas were also similar: 6.69 ± 1.95 mm(2) with iodixanol vs. 7.06 ± 2.06 mm(2) with dextran (correlation coefficient 0.984). The image quality and measurements during OCT image acquisition are similar for dextran and contrast. Dextran could be used instead of contrast for OCT imaging, especially in patients in whom contrast load minimization is desired. © 2013 Wiley Periodicals, Inc.

  20. A comparative study of the sensitivity of diffusion-related parameters obtained from diffusion tensor imaging, diffusional kurtosis imaging, q-space analysis and bi-exponential modelling in the early disease course (24 h) of hyperacute (6 h) ischemic stroke patients.

    Science.gov (United States)

    Duchêne, Gaëtan; Peeters, Frank; Peeters, André; Duprez, Thierry

    2017-08-01

    To compare the sensitivity and early temporal changes of diffusion parameters obtained from diffusion tensor imaging (DTI), diffusional kurtosis imaging (DKI), q-space analysis (QSA) and bi-exponential modelling in hyperacute stroke patients. A single investigational acquisition allowing the four diffusion analyses was performed on seven hyperacute stroke patients with a 3T system. The percentage change between ipsi- and contralateral regions were compared at admission and 24 h later. Two out of the seven patients were imaged every 6 h during this period. Kurtoses from both DKI and QSA were the most sensitive of the tested diffusion parameters in the few hours following ischemia. An early increase-maximum-decrease pattern of evolution was highlighted during the 24-h period for all parameters proportional to diffusion coefficients. A similar pattern was observed for both kurtoses in only one of two patients. Our comparison was performed using identical diffusion encoding timings and on patients in the same stage of their condition. Although preliminary, our findings confirm those of previous studies that showed enhanced sensitivity of kurtosis. A fine time mapping of diffusion metrics in hyperacute stroke patients was presented which advocates for further investigations on larger animal or human cohorts.

  1. Comparing the difference of measured GFR of ectopic pelvic kidney between anterior and posterior imaging processing in renal dynamic imaging

    International Nuclear Information System (INIS)

    Li Baojun; Zhao Deshan

    2014-01-01

    Objective: To compare and analyze the difference of measured glomerular filtration rate (GFR) of ectopic pelvic kidney between anterior and posterior imaging processing in renal dynamic imaging. Methods: There were 10 patients collected retrospectively, with ectopic kidneys in pelvic cavity confirmed by ultrasound, CT, renal dynamic imaging and other imaging modalities. All images of ectopic kidneys in renal dynamic imaging were processed by anterior and posterior methods respectively. The ectopic kidney was only processed in anterior imaging, ectopic kidney and contralateral normal kidney were processed in posterior imaging. Total GFR equalled the sum of GFR of normal kidney in posterior imaging and GFR of ectopic kidney in anterior imaging, was compared with total GFR of two kidneys in posterior imaging and GFR in two-sample method. All correlation analysis were completed between GFRs from three methods and all patients were followed up. Statistically paired t-test and bivariate correlation analysis test were used. Results: The mean GFR of ectopic kidney in anterior imaging equal to (27.48±12.24) ml/(min · 1.73 m 2 ). It was more than GFR [(10.71 ±4.74) ml/ (min · 1.73 m 2 )] in posterior imaging above 46% (t=5.481, P<0.01). There was no significant difference (t=-2.238, P>0.05), but better correlation (r=0.704, P<0.05) between total GFR in anterior imaging and GFR in two-sample method. There was significant difference (t=4.629, P<0.01)and worse correlation (r=0.576, P>0.05) between total GFR in posterior imaging and GFR in two-sample method. Conclusion: Comparing with GFR in posterior imaging, GFR in anterior imaging can more truly reflect function condition of ectopic pelvic kidney in renal dynamic imaging. (authors)

  2. Post-mortem imaging compared with autopsy in trauma victims--A systematic review.

    Science.gov (United States)

    Jalalzadeh, Hamid; Giannakopoulos, Georgios F; Berger, Ferco H; Fronczek, Judith; van de Goot, Frank R W; Reijnders, Udo J; Zuidema, Wietse P

    2015-12-01

    Post-mortem imaging or virtual autopsy is a rapidly advancing field of post-mortem investigations of trauma victims. In this review we evaluate the feasibility of complementation or replacement of conventional autopsy by post-mortem imaging in trauma victims. A systematic review was performed in compliance with the PRISMA guidelines. MEDLINE, Embase and Cochrane databases were systematically searched for studies published between January 2008 and January 2014, in which post-mortem imaging was compared to conventional autopsy in trauma victims. Studies were included when two or more trauma victims were investigated. Twenty-six studies were included, with a total number of 563 trauma victims. Post-mortem computer tomography (PMCT) was performed in 22 studies, post-mortem magnetic resonance imaging (PMMRI) in five studies and conventional radiography in two studies. PMCT and PMMRI both demonstrate moderate to high-grade injuries and cause of death accurately. PMCT is more sensitive than conventional autopsy or PMMRI in detecting skeletal injuries. For detecting minor organ and soft tissue injuries, autopsy remains superior to imaging. Aortic injuries are missed frequently by PMCT and PMMRI and form their main limitation. PMCT should be considered as an essential supplement to conventional autopsy in trauma victims since it detects many additional injuries. Despite some major limitations, PMCT could be used as an alternative for conventional autopsy in situations where conventional autopsy is rejected or unavailable. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. MRI compatibility of robot actuation techniques--a comparative study.

    Science.gov (United States)

    Fischer, Gregory S; Krieger, Axel; Iordachita, Iulian; Csoma, Csaba; Whitcomb, Louis L; Gabor, Fichtinger

    2008-01-01

    This paper reports an experimental evaluation of the following three different MRI-compatible actuators: a Shinsei ultrasonic motor a Nanomotion ultrasonic motor and a pneumatic cylinder actuator. We report the results of a study comparing the effect of these actuators on the signal to noise ratio (SNR) of MRJ images under a variety of experimental conditions. Evaluation was performed with the controller inside and outside the scanner room and with both 1.5T and 3T MRI scanners. Pneumatic cylinders function with no loss of SNR with controller both inside and outside of the scanner room. The Nanomotion motor performs with moderate loss of SNR when moving during imaging. The Shinsei is unsuitable for motion during imaging. All may be used when motion is appropriately interleaved with imaging cycles.

  4. MRI Compatibility of Robot Actuation Techniques – A Comparative Study

    Science.gov (United States)

    Fischer, Gregory S.; Krieger, Axel; Iordachita, Iulian; Csoma, Csaba; Whitcomb, Louis L.; Fichtinger, Gabor

    2010-01-01

    This paper reports an experimental evaluation of the following three different MRI-compatible actuators: a Shinsei ultrasonic motor, a Nanomotion ultrasonic motor and a pneumatic cylinder actuator. We report the results of a study comparing the effect of these actuators on the signal to noise ratio (SNR) of MRI images under a variety of experimental conditions. Evaluation was performed with the controller inside and outside the scanner room and with both 1.5T and 3T MRI scanners. Pneumatic cylinders function with no loss of SNR with controller both inside and outside of the scanner room. The Nanomotion motor performs with moderate loss of SNR when moving during imaging. The Shinsei is unsuitable for motion during imaging. All may be used when motion is appropriately interleaved with imaging cycles. PMID:18982643

  5. NMR imaging studies of coal

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Z.R.; Zhang, P.Z.; Ding, G.L.; Li, L.Y.; Ye, C.H. [University of Science and Technology, Beijing (China). Dept. of Chemistry

    1996-06-01

    The permeation transportation and swelling behavior of solvents into coal are investigated by NMR imaging using pyridine-d{sub 5} and acetone-d{sub 6}. Images of coal swollen with deuterated solvents illuminate proton distributions of mobile phases within the coal macromolecular networks. More information about the chemical and physical structure of coal can be obtained using NMR imaging techniques.

  6. Endometrial cancer: preoperative staging using three-dimensional T2-weighted turbo spin-echo and diffusion-weighted MR imaging at 3.0 T: a prospective comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Hori, Masatoshi; Kim, Tonsok; Onishi, Hiromitsu; Nakamoto, Atsushi; Tomiyama, Noriyuki [Osaka University Graduate School of Medicine, Department of Radiology, Suita, Osaka (Japan); Imaoka, Izumi; Kagawa, Yuki; Murakami, Takamichi [Kinki University School of Medicine, Department of Radiology, Osaka (Japan); Ueguchi, Takashi; Tatsumi, Mitsuaki [Osaka University Hospital, Department of Radiology, Osaka (Japan); Enomoto, Takayuki [Osaka University Graduate School of Medicine, Department of Obstetrics and Gynecology, Osaka (Japan); Niigata University School of Medicine, Department of Obstetrics and Gynecology, Niigata (Japan); Kimura, Tadashi [Osaka University Graduate School of Medicine, Department of Obstetrics and Gynecology, Osaka (Japan)

    2013-08-15

    To prospectively assess the efficacy of 3-T magnetic resonance (MR) imaging using the three-dimensional turbo spin-echo T2-weighted and diffusion-weighted technique (3D-TSE/DW) compared with that of conventional imaging using the two-dimensional turbo spin-echo T2-weighted and dynamic contrast-enhanced technique (2D-TSE/DCE) for the preoperative staging of endometrial cancer, with pathological analysis as the reference standard. Seventy-one women with endometrial cancer underwent MR imaging using 3D-TSE/DW (b = 1,000 s/mm{sup 2}) and 2D-TSE/DCE. Two radiologists independently assessed the two imaging sets. Accuracy, sensitivity, and specificity for staging were analysed with the McNemar test; the areas under the receiver operating characteristic curve (Az) were compared with a univariate z-score test. The results for assessing deep myometrial invasion, accuracy, sensitivity, specificity and Az, respectively, were as follows: 3D-TSE/DW - observer 1, 87 %, 95 %, 85 % and 0.96; observer 2, 92 %, 84 %, 94 % and 0.95; 2D-TSE/DCE - observer 1, 80 %, 79 %, 81 % and 0.89; observer 2, 86 %, 84 %, 87 % and 0.86. Most of the values were higher with 3D-TSE/DW without significant differences (P > 0.12). For assessing cervical stromal invasion, there were no significant differences in those values for both observers (P > 0.6). Accuracy of 3D-TSE/DW was at least equivalent to that of the conventional technique for the preoperative assessment of endometrial cancer. (orig.)

  7. Comparing personal image collections with PICTuReVis

    NARCIS (Netherlands)

    van der Corput, P.N.A.; van Wijk, J.J.

    2017-01-01

    Digital image collections contain a wealth of information, which for instance can be used to trace illegal activities and investigate criminal networks. We present a method that enables analysts to reveal relations among people, based on the patterns in their collections. Similar temporal and

  8. How does c-view image quality compare with conventional 2D FFDM?

    Science.gov (United States)

    Nelson, Jeffrey S; Wells, Jered R; Baker, Jay A; Samei, Ehsan

    2016-05-01

    The FDA approved the use of digital breast tomosynthesis (DBT) in 2011 as an adjunct to 2D full field digital mammography (FFDM) with the constraint that all DBT acquisitions must be paired with a 2D image to assure adequate interpretative information is provided. Recently manufacturers have developed methods to provide a synthesized 2D image generated from the DBT data with the hope of sparing patients the radiation exposure from the FFDM acquisition. While this much needed alternative effectively reduces the total radiation burden, differences in image quality must also be considered. The goal of this study was to compare the intrinsic image quality of synthesized 2D c-view and 2D FFDM images in terms of resolution, contrast, and noise. Two phantoms were utilized in this study: the American College of Radiology mammography accreditation phantom (ACR phantom) and a novel 3D printed anthropomorphic breast phantom. Both phantoms were imaged using a Hologic Selenia Dimensions 3D system. Analysis of the ACR phantom includes both visual inspection and objective automated analysis using in-house software. Analysis of the 3D anthropomorphic phantom includes visual assessment of resolution and Fourier analysis of the noise. Using ACR-defined scoring criteria for the ACR phantom, the FFDM images scored statistically higher than c-view according to both the average observer and automated scores. In addition, between 50% and 70% of c-view images failed to meet the nominal minimum ACR accreditation requirements-primarily due to fiber breaks. Software analysis demonstrated that c-view provided enhanced visualization of medium and large microcalcification objects; however, the benefits diminished for smaller high contrast objects and all low contrast objects. Visual analysis of the anthropomorphic phantom showed a measureable loss of resolution in the c-view image (11 lp/mm FFDM, 5 lp/mm c-view) and loss in detection of small microcalcification objects. Spectral analysis of the

  9. How does C-VIEW image quality compare with conventional 2D FFDM?

    International Nuclear Information System (INIS)

    Nelson, Jeffrey S.; Wells, Jered R.; Baker, Jay A.; Samei, Ehsan

    2016-01-01

    Purpose: The FDA approved the use of digital breast tomosynthesis (DBT) in 2011 as an adjunct to 2D full field digital mammography (FFDM) with the constraint that all DBT acquisitions must be paired with a 2D image to assure adequate interpretative information is provided. Recently manufacturers have developed methods to provide a synthesized 2D image generated from the DBT data with the hope of sparing patients the radiation exposure from the FFDM acquisition. While this much needed alternative effectively reduces the total radiation burden, differences in image quality must also be considered. The goal of this study was to compare the intrinsic image quality of synthesized 2D C-VIEW and 2D FFDM images in terms of resolution, contrast, and noise. Methods: Two phantoms were utilized in this study: the American College of Radiology mammography accreditation phantom (ACR phantom) and a novel 3D printed anthropomorphic breast phantom. Both phantoms were imaged using a Hologic Selenia Dimensions 3D system. Analysis of the ACR phantom includes both visual inspection and objective automated analysis using in-house software. Analysis of the 3D anthropomorphic phantom includes visual assessment of resolution and Fourier analysis of the noise. Results: Using ACR-defined scoring criteria for the ACR phantom, the FFDM images scored statistically higher than C-VIEW according to both the average observer and automated scores. In addition, between 50% and 70% of C-VIEW images failed to meet the nominal minimum ACR accreditation requirements—primarily due to fiber breaks. Software analysis demonstrated that C-VIEW provided enhanced visualization of medium and large microcalcification objects; however, the benefits diminished for smaller high contrast objects and all low contrast objects. Visual analysis of the anthropomorphic phantom showed a measureable loss of resolution in the C-VIEW image (11 lp/mm FFDM, 5 lp/mm C-VIEW) and loss in detection of small microcalcification

  10. How does C-VIEW image quality compare with conventional 2D FFDM?

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Jeffrey S., E-mail: nelson.jeffrey@duke.edu; Wells, Jered R. [Department of Radiology, Clinical Imaging Physics Group, Duke University Medical Center, Durham, North Carolina 27705 (United States); Baker, Jay A. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Samei, Ehsan [Department of Radiology, Clinical Imaging Physics Group, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Departments of Biomedical Engineering and Electrical and Computer Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina 27705 (United States)

    2016-05-15

    Purpose: The FDA approved the use of digital breast tomosynthesis (DBT) in 2011 as an adjunct to 2D full field digital mammography (FFDM) with the constraint that all DBT acquisitions must be paired with a 2D image to assure adequate interpretative information is provided. Recently manufacturers have developed methods to provide a synthesized 2D image generated from the DBT data with the hope of sparing patients the radiation exposure from the FFDM acquisition. While this much needed alternative effectively reduces the total radiation burden, differences in image quality must also be considered. The goal of this study was to compare the intrinsic image quality of synthesized 2D C-VIEW and 2D FFDM images in terms of resolution, contrast, and noise. Methods: Two phantoms were utilized in this study: the American College of Radiology mammography accreditation phantom (ACR phantom) and a novel 3D printed anthropomorphic breast phantom. Both phantoms were imaged using a Hologic Selenia Dimensions 3D system. Analysis of the ACR phantom includes both visual inspection and objective automated analysis using in-house software. Analysis of the 3D anthropomorphic phantom includes visual assessment of resolution and Fourier analysis of the noise. Results: Using ACR-defined scoring criteria for the ACR phantom, the FFDM images scored statistically higher than C-VIEW according to both the average observer and automated scores. In addition, between 50% and 70% of C-VIEW images failed to meet the nominal minimum ACR accreditation requirements—primarily due to fiber breaks. Software analysis demonstrated that C-VIEW provided enhanced visualization of medium and large microcalcification objects; however, the benefits diminished for smaller high contrast objects and all low contrast objects. Visual analysis of the anthropomorphic phantom showed a measureable loss of resolution in the C-VIEW image (11 lp/mm FFDM, 5 lp/mm C-VIEW) and loss in detection of small microcalcification

  11. Comparative evaluation of the porta hepatis/hepatoduodenal ligament with CT and MR imaging

    International Nuclear Information System (INIS)

    Silverman, P.M.; Feuerstein, I.M.; Zeman, R.K.; Jaffe, M.H.; Garra, B.S.

    1988-01-01

    CT and MR imaging were compared in a retrospective evaluation of 16 patients with abnormalities, predominantly neoplasms, of the porta hepatis/hepatoduodenal ligament. Masses on CT were of decreased density compared with that of liver and were seen in contrast to surrounding periportal fat. On MR images, T1-weighted images demonstrated findings similar to those of CT. T2-weighted images clearly depicted intrahepatic lesions but less distinctly depicted lesions surrounded by fat. Short inversion recovery (STIR) images better demonstrated tumor relative to fat. CT was better than all MR imaging sequences in one of 16 cases, whereas at least one MR imaging sequence was better than CT in six of 16. In nine cases, CT was equivalent to the best MR imaging sequence. In five of six cases where MR imaging was better than CT, STIR sequences were most favorable. In conclusion, MR imaging provided a valuable technique for assessing abnormalities of the porta hepatis/hepatoduodenal ligament

  12. COMPARATIVE STUDY ON SPECIFIC AND EARLY DETECTION ...

    African Journals Online (AJOL)

    The objective of this study was to compare the sensitivity and specificity of smear and culture methods with rapid serological EIA myco kits manufactured by Omega diagnostics, for the early detection of Mycobacterium tuberculosis (MTB) complex. Sera from various categories of smear and culture results were compared ...

  13. A comparative study of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and 99mTc-MDP whole-body bone scanning for imaging osteolytic bone metastases

    International Nuclear Information System (INIS)

    Zhang, Lin; Chen, Lihua; Xie, Qiao; Zhang, Yongke; Cheng, Lin; Li, Haitao; Wang, Jian

    2015-01-01

    The objective of this study was to evaluate the feasibility and diagnostic value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) and 99m Tc-methylenediphosphonate (MDP) whole-body bone scanning (BS) for the detection of osteolytic bone metastases. Thirty-four patients with pathologically confirmed malignancies and suspected osteolytic bone metastases underwent 18 F-FDG PET/CT and 99m Tc-MDP whole-body BS within 30 days. The sensitivity, specificity, and accuracy with respect to the diagnosis of osteolytic bone metastases and bone lesions were compared between the two imaging methods. The sensitivity, specificity, and accuracy of 18 F-FDG PET/CT for the diagnosis of osteolytic bone metastases were 94.3% (95% confidence interval [CI], 91.6–96.2%), 83.3% (95% CI, 43.6–96.9%), and 94.2% (95% CI, 91.5–96.1%), respectively. It was found that 99m Tc-MDP whole-body BS could discriminate between patients with 50.2% (95% CI, 45.4–55.1%) sensitivity, 50.0% (95% CI, 18.8–81.2%) specificity, and 50.2% (95% CI, 45.5–55.1%) accuracy. 18 F-FDG PET/CT achieved higher sensitivity, specificity, and accuracy in detecting osteolytic bone metastases than 99mTc-MDP whole-body BS (p<0.001). F-FDG PET/CT has a higher diagnostic value than 99m Tc-MDP whole-body BS in the detection of osteolytic bone metastases, especially in the vertebra

  14. Perfusion magnetic resonance imaging provides additional information as compared to anatomical imaging for decision-making in vestibular schwannoma

    International Nuclear Information System (INIS)

    Kleijwegt, M.C.; Mey, A.G.L. van der; Wiggers-deBruine, F.T.; Malessy, M.J.A; Osch, M.J.P. van

    2016-01-01

    •DSC/ASL-MRI can be acquired in growing VS with sufficient image quality.•In most patients DSC and ASL techniques provide similar qualitative scores.•These techniques can be of importance in future decision-making. DSC/ASL-MRI can be acquired in growing VS with sufficient image quality. In most patients DSC and ASL techniques provide similar qualitative scores. These techniques can be of importance in future decision-making. The added value of perfusion MRI for decision-making in vestibular schwannoma (VS) patients is unknown. MRI offers two perfusion methods: the first employing contrast agent (dynamic susceptibility contrast (DSC)-MRI) that provides information on cerebral blood volume (CBV) and cerebral blood flow (CBF), the second by magnetic labeling of blood (arterial spin labeling (ASL)-MRI), providing CBF-images. The goal of the current study is to investigate whether DSC and ASL perfusion MRI provides complimentary information to current anatomical imaging in treatment selection process of VS. Nine patients with growing VS with extrameatal diameter >9 mm were included (>2 mm/year and 20% volume expansion/year) and one patient with 23 mm extrameatal VS without growth. DSC and ASL perfusion MRI were obtained on 3 T MRI. Perfusion in VS was scored as hyperintense, hypointense or isointense compared to the contralateral region. Seven patients showed hyperintense signal on DSC and ASL sequences. Three patients showed iso- or hypointense signal on at least one perfusion map (1 patient hypointense on both DSC-MRI and ASL; 1 patient isointense on DSC-CBF; 1 patient isointense on ASL). All patients showed enhancement on post-contrast T1 anatomical scan. Perfusion MR provides additional information compared to anatomical imaging for decision-making in VS

  15. Visual grading of 2D and 3D functional MRI compared with image-based descriptive measures

    Energy Technology Data Exchange (ETDEWEB)

    Ragnehed, Mattias [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences, Division of Radiological Sciences/Radiology, Faculty of Health Sciences, Linkoeping (Sweden); Leinhard, Olof Dahlqvist; Pihlsgaard, Johan; Lundberg, Peter [Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Linkoeping University, Division of Radiological Sciences, Radiation Physics, IMH, Linkoeping (Sweden); Wirell, Staffan [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University Hospital, Department of Radiology, Linkoeping (Sweden); Soekjer, Hannibal; Faegerstam, Patrik [Linkoeping University Hospital, Department of Radiology, Linkoeping (Sweden); Jiang, Bo [Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Smedby, Oerjan; Engstroem, Maria [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden)

    2010-03-15

    A prerequisite for successful clinical use of functional magnetic resonance imaging (fMRI) is the selection of an appropriate imaging sequence. The aim of this study was to compare 2D and 3D fMRI sequences using different image quality assessment methods. Descriptive image measures, such as activation volume and temporal signal-to-noise ratio (TSNR), were compared with results from visual grading characteristics (VGC) analysis of the fMRI results. Significant differences in activation volume and TSNR were not directly reflected by differences in VGC scores. The results suggest that better performance on descriptive image measures is not always an indicator of improved diagnostic quality of the fMRI results. In addition to descriptive image measures, it is important to include measures of diagnostic quality when comparing different fMRI data acquisition methods. (orig.)

  16. Feedforward Object-Vision Models Only Tolerate Small Image Variations Compared to Human

    Directory of Open Access Journals (Sweden)

    Masoud eGhodrati

    2014-07-01

    Full Text Available Invariant object recognition is a remarkable ability of primates' visual system that its underlying mechanism has constantly been under intense investigations. Computational modelling is a valuable tool toward understanding the processes involved in invariant object recognition. Although recent computational models have shown outstanding performances on challenging image databases, they fail to perform well when images with more complex variations of the same object are applied to them. Studies have shown that making sparse representation of objects by extracting more informative visual features through a feedforward sweep can lead to higher recognition performances. Here, however, we show that when the complexity of image variations is high, even this approach results in poor performance compared to humans. To assess the performance of models and humans in invariant object recognition tasks, we built a parametrically controlled image database consisting of several object categories varied in different dimensions and levels, rendered from 3D planes. Comparing the performance of several object recognition models with human observers shows that only in low-level image variations the models perform similar to humans in categorization tasks. Furthermore, the results of our behavioral experiments demonstrate that, even under difficult experimental conditions (i.e. briefly presented masked stimuli with complex image variations, human observers performed outstandingly well, suggesting that the models are still far from resembling humans in invariant object recognition. Taken together, we suggest that learning sparse informative visual features, although desirable, is not a complete solution for future progresses in object-vision modelling. We show that this approach is not of significant help in solving the computational crux of object recognition (that is invariant object recognition when the identity-preserving image variations become more complex.

  17. Comparing an FPGA to a Cell for an Image Processing Application

    Science.gov (United States)

    Rakvic, Ryan N.; Ngo, Hau; Broussard, Randy P.; Ives, Robert W.

    2010-12-01

    Modern advancements in configurable hardware, most notably Field-Programmable Gate Arrays (FPGAs), have provided an exciting opportunity to discover the parallel nature of modern image processing algorithms. On the other hand, PlayStation3 (PS3) game consoles contain a multicore heterogeneous processor known as the Cell, which is designed to perform complex image processing algorithms at a high performance. In this research project, our aim is to study the differences in performance of a modern image processing algorithm on these two hardware platforms. In particular, Iris Recognition Systems have recently become an attractive identification method because of their extremely high accuracy. Iris matching, a repeatedly executed portion of a modern iris recognition algorithm, is parallelized on an FPGA system and a Cell processor. We demonstrate a 2.5 times speedup of the parallelized algorithm on the FPGA system when compared to a Cell processor-based version.

  18. Comparing an FPGA to a Cell for an Image Processing Application

    Directory of Open Access Journals (Sweden)

    Robert W. Ives

    2010-01-01

    Full Text Available Modern advancements in configurable hardware, most notably Field-Programmable Gate Arrays (FPGAs, have provided an exciting opportunity to discover the parallel nature of modern image processing algorithms. On the other hand, PlayStation3 (PS3 game consoles contain a multicore heterogeneous processor known as the Cell, which is designed to perform complex image processing algorithms at a high performance. In this research project, our aim is to study the differences in performance of a modern image processing algorithm on these two hardware platforms. In particular, Iris Recognition Systems have recently become an attractive identification method because of their extremely high accuracy. Iris matching, a repeatedly executed portion of a modern iris recognition algorithm, is parallelized on an FPGA system and a Cell processor. We demonstrate a 2.5 times speedup of the parallelized algorithm on the FPGA system when compared to a Cell processor-based version.

  19. Clinical findings versus imaging studies in the diagnosis of infantile ...

    African Journals Online (AJOL)

    Background: Infantile hypertrophic pyloric stenosis is the most common surgical cause of vomiting in early infancy and can be diagnosed clinically or by imaging studies. Objectives: The aim of this study was to assess the accuracy of clinical examination compared with ultrasound and upper gastrointestinal contrast imaging ...

  20. Effects of the change in cutoff values for human epidermal growth factor receptor 2 status by immunohistochemistry and fluorescence in situ hybridization: a study comparing conventional brightfield microscopy, image analysis-assisted microscopy, and interobserver variation.

    Science.gov (United States)

    Atkinson, Roscoe; Mollerup, Jens; Laenkholm, Anne-Vibeke; Verardo, Mark; Hawes, Debra; Commins, Deborah; Engvad, Birte; Correa, Adrian; Ehlers, Charlotte Cort; Nielsen, Kirsten Vang

    2011-08-01

    New guidelines for HER2 testing have been introduced. To evaluate the difference in HER2 assessment after introduction of new cutoff levels for both immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) and to compare interobserver agreement and time to score between image analysis and conventional microscopy. Samples from 150 patients with breast cancer were scored by 7 pathologists using conventional microscopy, with a cutoff of both 10% and 30% IHC-stained cells, and using automated microscopy with image analysis. The IHC results were compared individually and to HER2 status as determined by FISH, using both the approved cutoff of 2.0 and the recently introduced cutoff of 2.2. High concordance was found in IHC scoring among the 7 pathologists. The 30% cutoff led to slightly fewer positive IHC observations. Introduction of a FISH equivocal zone affected 4% of the FISH scores. If cutoff for FISH is kept at 2.0, no difference in patient selection is found between the 10% and the 30% IHC cutoff. Among the 150 breast cancer samples, the new 30% IHC and 2.2 FISH cutoff levels resulted in one case without a firm diagnosis because both IHC and FISH were equivocal. Automated microscopy and image analysis-assisted IHC led to significantly better interobserver agreement among the 7 pathologists, with an increase in mean scoring time of only about 30 seconds per slide. The change in cutoff levels led to a higher concordance between IHC and FISH, but fewer samples were classified as HER2 positive.

  1. Mathematics education and comparative historical studies

    Directory of Open Access Journals (Sweden)

    Wagner RODRIGUES VALENTE

    2013-11-01

    Full Text Available This paper has as its aims: to characterize the area of research «history of mathematics education» and to defend the idea that mathematics education has constituted a privileged research theme within the field of comparative historical studies. To achieve these aims, the text includes references to a review of the literature concerning comparative studies, the analysis of two fundamental moments focused on attempts to internationalize the mathematics curriculum, both of which occurred during the 20th century, and, to end, a case study emanating from an international cooperation between researchers in Brazil and Portugal.

  2. Comparative study of bioethanol production from sugarcane ...

    African Journals Online (AJOL)

    The study was designed to compare the bioethanol production from Zymomonas mobilis and Saccharomyces cerevisiae using molasses as production medium. The focus was on the retention time at lab scale. Bioethanol and petroleum blend can be used in existing gasoline engines. Present study showed a more ...

  3. Supplementary data: Comparative studies on sequence ...

    Indian Academy of Sciences (India)

    Unknown

    Page 1. Supplementary data: Comparative studies on sequence characteristics around translation initiation codon in four eukaryotes. Qingpo Liu and Qingzhong Xue. J. Genet. 84, 317–322. Table 1. Spearman's rank correlation coefficients of 39 base positions around the AUG codon in the four eukaryotic species studied.

  4. TREE STEM RECONSTRUCTION USING VERTICAL FISHEYE IMAGES: A PRELIMINARY STUDY

    Directory of Open Access Journals (Sweden)

    A. Berveglieri

    2016-06-01

    Full Text Available A preliminary study was conducted to assess a tree stem reconstruction technique with panoramic images taken with fisheye lenses. The concept is similar to the Structure from Motion (SfM technique, but the acquisition and data preparation rely on fisheye cameras to generate a vertical image sequence with height variations of the camera station. Each vertical image is rectified to four vertical planes, producing horizontal lateral views. The stems in the lateral view are rectified to the same scale in the image sequence to facilitate image matching. Using bundle adjustment, the stems are reconstructed, enabling later measurement and extraction of several attributes. The 3D reconstruction was performed with the proposed technique and compared with SfM. The preliminary results showed that the stems were correctly reconstructed by using the lateral virtual images generated from the vertical fisheye images and with the advantage of using fewer images and taken from one single station.

  5. Three-dimensional volume rendering of the ankle based on magnetic resonance images enables the generation of images comparable to real anatomy.

    Science.gov (United States)

    Anastasi, Giuseppe; Cutroneo, Giuseppina; Bruschetta, Daniele; Trimarchi, Fabio; Ielitro, Giuseppe; Cammaroto, Simona; Duca, Antonio; Bramanti, Placido; Favaloro, Angelo; Vaccarino, Gianluigi; Milardi, Demetrio

    2009-11-01

    We have applied high-quality medical imaging techniques to study the structure of the human ankle. Direct volume rendering, using specific algorithms, transforms conventional two-dimensional (2D) magnetic resonance image (MRI) series into 3D volume datasets. This tool allows high-definition visualization of single or multiple structures for diagnostic, research, and teaching purposes. No other image reformatting technique so accurately highlights each anatomic relationship and preserves soft tissue definition. Here, we used this method to study the structure of the human ankle to analyze tendon-bone-muscle relationships. We compared ankle MRI and computerized tomography (CT) images from 17 healthy volunteers, aged 18-30 years (mean 23 years). An additional subject had a partial rupture of the Achilles tendon. The MRI images demonstrated superiority in overall quality of detail compared to the CT images. The MRI series accurately rendered soft tissue and bone in simultaneous image acquisition, whereas CT required several window-reformatting algorithms, with loss of image data quality. We obtained high-quality digital images of the human ankle that were sufficiently accurate for surgical and clinical intervention planning, as well as for teaching human anatomy. Our approach demonstrates that complex anatomical structures such as the ankle, which is rich in articular facets and ligaments, can be easily studied non-invasively using MRI data.

  6. Comparative Studies: historical, epistemological and methodological notes

    Directory of Open Access Journals (Sweden)

    Juan Ignacio Piovani

    2017-09-01

    Full Text Available In this article some historical, epistemological and methodological issues related to comparative studies in the social sciences are addressed, with specific reference to the field of education. The starting point is a discussion of the meaning of comparison, its logical structure and its presence in science and in everyday life. It follows the presentation and critical appraisal of the perspectives regarding comparison as a scientific method. It is argued that, even rejecting this restrictive meaning of comparison as a method, there is some consensus on the specificity of comparative studies within the social sciences. And in relation to them, the article address in more detail those studies that can be defined as trans-contextual (cross-national and cross-cultural, with emphasis on the main methodological and technical challenges they face. The socio-historical comparative perspective, which has gained importance in recent years in the field of education, is also discussed.

  7. A Comparative Study on Error Analysis

    DEFF Research Database (Denmark)

    Wu, Xiaoli; Zhang, Chun

    2015-01-01

    Title: A Comparative Study on Error Analysis Subtitle: - Belgian (L1) and Danish (L1) learners’ use of Chinese (L2) comparative sentences in written production Xiaoli Wu, Chun Zhang Abstract: Making errors is an inevitable and necessary part of learning. The collection, classification and analysis...... the occurrence of errors either in linguistic or pedagogical terms. The purpose of the current study is to demonstrate the theoretical and practical relevance of error analysis approach in CFL by investigating two cases - (1) Belgian (L1) learners’ use of Chinese (L2) comparative sentences in written production...... of errors in the written and spoken production of L2 learners has a long tradition in L2 pedagogy. Yet, in teaching and learning Chinese as a foreign language (CFL), only handful studies have been made either to define the ‘error’ in a pedagogically insightful way or to empirically investigate...

  8. Comparative study of fast T 2-weighted images using respiratory triggered, breath-hold, fat suppression and phased array multi coil for liver evaluation by magnetic resonance imaging; Estudo comparativo das sequencias rapidas ponderadas em T2, utilizando-se sincronizacao respiratoria, apneia, supressao de gordura, bobina de corpo e bobina de sinergia para a avaliacao do figado pela ressonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Abbehusen, Cristiane L.; D' Ippolito, Giuseppe; Palacio, Glaucia A.S.; Szejnfeld, Jacob [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina (EPM). Dept. de Diagnostico por Imagem]. E-mail: cabbehusen@hotmail.com

    2003-10-01

    The objective of this study was to compare both qualitatively and quantitatively six T 2-weighted turbo spin-echo sequences varying the respiratory compensation technique, associating or not fat tissue suppression and using different types of coils. We performed a prospective study of 71 consecutive patients that were submitted to MRI of the liver using a 1.5 T magnet. The six following pulse sequences were used: fat-suppressed respiratory triggered with conventional body coil; breath-hold fat-suppressed with conventional body coil; non-suppressed respiratory triggered with conventional body coil; breath-hold non fat-suppressed with conventional body coil; fat-suppressed respiratory triggered with phased-array multi coil; breath-hold fat-suppressed with phased-array multi coil. Images were analyzed quantitatively by measuring the signal-to-noise ratios and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and the presence of artifacts. Results: the qualitative analysis showed that the mean values obtained with the six sequences were 7.8, 4.6, 7.9, 5.2, 6.7 and 4.6 respectively. The respiratory-triggered sequences were better than the breath-hold sequences in both qualitative and quantitative analysis (p < 0.001). No significant differences in the values of signal-to-noise ratios and in overall image quality were found between the sequences with and without fat suppression (p . 0.05). The sequences using the body coil were similar in terms of image quality (p . 0.05) and better regarding signal-to-noise ratios than those obtained with the phased=array multi coil (p ,0.001). Our qualitative and quantitative results suggest that the best MRI sequences for the valuation of the liver are the sequences with respiratory triggering using a conventional body coil, with or without fat suppression. (author)

  9. Recognition of Faces in Unconstrained Environments: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Javier Ruiz-del-Solar

    2009-01-01

    Full Text Available The aim of this work is to carry out a comparative study of face recognition methods that are suitable to work in unconstrained environments. The analyzed methods are selected by considering their performance in former comparative studies, in addition to be real-time, to require just one image per person, and to be fully online. In the study two local-matching methods, histograms of LBP features and Gabor Jet descriptors, one holistic method, generalized PCA, and two image-matching methods, SIFT-based and ERCF-based, are analyzed. The methods are compared using the FERET, LFW, UCHFaceHRI, and FRGC databases, which allows evaluating them in real-world conditions that include variations in scale, pose, lighting, focus, resolution, facial expression, accessories, makeup, occlusions, background and photographic quality. Main conclusions of this study are: there is a large dependence of the methods on the amount of face and background information that is included in the face's images, and the performance of all methods decreases largely with outdoor-illumination. The analyzed methods are robust to inaccurate alignment, face occlusions, and variations in expressions, to a large degree. LBP-based methods are an excellent election if we need real-time operation as well as high recognition rates.

  10. Bone scintigraphy in post-SARS patients and compared with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Wang Qian; Huang Lili; Qin Shuling

    2004-01-01

    Objective: To study the characteristics of bone scintigraphy in post-SARS patients and evaluate the usefulness of bone scintigraphy in the prediction of avascular osteonecrosis (AVN) comparing with the MR imaging.. Methods: Our study included 66 patients who were diagnosed as SARS based on the diagnostic criteria issued by the Ministry of Health of China (MHC), including 46 women and 20 men. Their ages ranged from 19 to 63 years (mean, 31.6±0.1 years). All of the patients were treated with methyprednisonlone, rabavirin, broad spectrum antimicrobials and supportive therapy. Dosage of methyprednisonlone was 80∼800 mg/d for 4-72 days. Of them, varied seat of joint pain occurred in 47 patients 3 to 18 weeks after the onset of SARS. Since multiple joints were involved in many patients, bone scintigraphy was performed for screening AVN. The other 19 patients without of evident joint pain were also examined as their demand. Informed consents were obtained in all of the examined patients. No previously joint pain or trauma history was found in this group of patients. Of the 66 patients, planer X-ray was performed in 34 of the symptomatic patients previous to the scintigraphy, but it was negative in all. MR examination was performed in 54 patients before or after the scintigraphy, and the interval between two the tests was average of 8 days (range, 0 to 30 days). In addition, 27 consecutive cases aged lower than 45 years (mean, 40.4±0.8 years) with breast cancer who underwent bone scintigraphy for screening metastastic disease and had negative results were also involved as a control group. Whole body skeletal scintigraphy was performed 3 hours after intravenous administration of technetium-99m methylene-diphosphonate 740 MBq. Increased uptake lesion seen in the limb joints was defined as positive, but 'hot patella' sign was considered to be non diagnostic value. When a lesion was found in the whole body imaging, corresponding regional image was further taken. Two

  11. An exploratory study of the relationship between store image, trust ...

    African Journals Online (AJOL)

    2011-08-26

    Aug 26, 2011 ... results, this study shows that compared to corporate-owned stores, ..... 'Exploring store image, customer satisfaction and customer ... strategy: Dimensions, antecedents, and performance outcomes', Journal of Marketing,.

  12. Automated image-matching technique for comparative diagnosis of the liver on CT examination

    International Nuclear Information System (INIS)

    Okumura, Eiichiro; Sanada, Shigeru; Suzuki, Masayuki; Tsushima, Yoshito; Matsui, Osamu

    2005-01-01

    When interpreting enhanced computer tomography (CT) images of the upper abdomen, radiologists visually select a set of images of the same anatomical positions from two or more CT image series (i.e., non-enhanced and contrast-enhanced CT images at arterial and delayed phase) to depict and to characterize any abnormalities. The same process is also necessary to create subtraction images by computer. We have developed an automated image selection system using a template-matching technique that allows the recognition of image sets at the same anatomical position from two CT image series. Using the template-matching technique, we compared several anatomical structures in each CT image at the same anatomical position. As the position of the liver may shift according to respiratory movement, not only the shape of the liver but also the gallbladder and other prominent structures included in the CT images were compared to allow appropriate selection of a set of CT images. This novel technique was applied in 11 upper abdominal CT examinations. In CT images with a slice thickness of 7.0 or 7.5 mm, the percentage of image sets selected correctly by the automated procedure was 86.6±15.3% per case. In CT images with a slice thickness of 1.25 mm, the percentages of correct selection of image sets by the automated procedure were 79.4±12.4% (non-enhanced and arterial-phase CT images) and 86.4±10.1% (arterial- and delayed-phase CT images). This automated method is useful for assisting in interpreting CT images and in creating digital subtraction images. (author)

  13. MRI Compatibility of Robot Actuation Techniques – A Comparative Study

    OpenAIRE

    Fischer, Gregory S.; Krieger, Axel; Iordachita, Iulian; Csoma, Csaba; Whitcomb, Louis L.; Fichtinger, Gabor

    2008-01-01

    This paper reports an experimental evaluation of the following three different MRI-compatible actuators: a Shinsei ultrasonic motor, a Nanomotion ultrasonic motor and a pneumatic cylinder actuator. We report the results of a study comparing the effect of these actuators on the signal to noise ratio (SNR) of MRI images under a variety of experimental conditions. Evaluation was performed with the controller inside and outside the scanner room and with both 1.5T and 3T MRI scanners. Pneumatic cy...

  14. A comparative study of map use

    DEFF Research Database (Denmark)

    Bouvin, Niels Olof; Brodersen, Ann Christina; Bødker, Susanne

    2006-01-01

    We present a study comparing the handling of three kinds of maps, each on a physical device: a paper map, a tablet-PC based map, and a cellular phone based one. Six groups of users were asked to locate eight landmarks, looking out a window, and using a particular map. We have begun analyzing video...

  15. A comparative study of microbiological and physicochemical ...

    African Journals Online (AJOL)

    A comparative study of microbiological and physicochemical characteristics of water distributed from two water treatment plants in Rwanda. ... Thus, as recommendation to WASAC authority, there is a need for improvement in the water management strategy for better water quality especially along the distribution network.

  16. Comparative study of quantum anharmonic potentials

    International Nuclear Information System (INIS)

    Amore, Paolo; Aranda, Alfredo; De Pace, Arturo; Lopez, Jorge A.

    2004-01-01

    We perform a study of various anharmonic potentials using a recently developed method. We calculate both the wave functions and the energy eigenvalues for the ground and first excited states of the quartic, sextic and octic potentials with high precision, comparing the results with other techniques available in the literature

  17. Comparative study of potato cultivation through micropropagation ...

    African Journals Online (AJOL)

    sonu

    Comparative study of potato cultivation through micropropagation and conventional farming methods .... and Murate potash were used as fertilizer source of nitrogen, phosphorus and potassium, respectively (Table 1) ..... through Tissue culture- Application and Feasibility. U.S.D.A.,. Beltsville. Agric. Res. Sci. Educ. Admin.

  18. Evaluation of D-isomers of 4-borono-2-18F-fluoro-phenylalanine and O-11C-methyl-tyrosine as brain tumor imaging agents: a comparative PET study with their L-isomers in rat brain glioma.

    Science.gov (United States)

    Kanazawa, Masakatsu; Nishiyama, Shingo; Hashimoto, Fumio; Kakiuchi, Takeharu; Tsukada, Hideo

    2018-06-13

    The potential of the D-isomerization of 4-borono-2- 18 F-fluoro-phenylalanine ( 18 F-FBPA) to improve its target tumor to non-target normal brain tissue ratio (TBR) was evaluated in rat brain glioma and compared with those of L- and D- 11 C-methyl-tyrosine ( 11 C-CMT). The L- or D-isomer of 18 F-FBPA was injected into rats through the tail vein, and their whole body kinetics and distributions were assessed using the tissue dissection method up to 90 min after the injection. The kinetics of L- and D- 18 F-FBPA or L- and D- 11 C-CMT in the C-6 glioma-inoculated rat brain were measured for 90 or 60 min, respectively, using high-resolution animal PET, and their TBRs were assessed. Tissue dissection analyses showed that D- 18 F-FBPA uptake was significantly lower than that of L- 18 F-FBPA in the brain and abdominal organs, except for the kidney and bladder, reflecting the faster elimination rate of D- 18 F-FBPA than L- 18 F-FBPA from the blood to the urinary tract. PET imaging using 18 F-FBPA revealed that although the brain uptake of D- 18 F-FBPA was significantly lower than that of L- 18 F-FBPA, the TBR of the D-isomer improved to 6.93 from 1.45 for the L-isomer. Similar results were obtained with PET imaging using 11 C-CMT with a smaller improvement in TBR to 1.75 for D- 11 C-CMT from 1.33 for L- 11 C-CMT. The present results indicate that D- 18 F-FBPA is a better brain tumor imaging agent with higher TBR than its original L-isomer and previously reported tyrosine-based PET imaging agents. This improved TBR of D- 18 F-FBPA without any pre-treatments, such as tentative blood-brain barrier disruption using hyperosmotic agents or sonication, suggests that the D-isomerization of BPA results in the more selective accumulation of 10 B in tumor cells that is more effective and less toxic than conventional L-BPA.

  19. AMERICAN EDUCATION SYSTEM: A COMPARATIVE STUDY

    OpenAIRE

    BAS, Gökhan

    2016-01-01

    The purpose of this study was to introduce the Education System of the United States of America (USA) and to compare it with the Turkish Education System. The Education System of the United States of America was held from different factors (e.g., education structure, curriculum and instruction, principal selection, educational supervision, special education ,teacher education, finance for education, international examinations, vs.) and these factors were explained under headlines in the study...

  20. A comparative study of various advanced fusions

    International Nuclear Information System (INIS)

    Momota, H.; Tomita, Y.; Nomura, Y.

    1983-01-01

    For the purpose of comparing the merits and demerits of various advanced fuel cycles, parametric studies of operation conditions are examined. The effects of nuclear elastic collisions and synchrotron radiation are taken into account. It is found that the high-#betta# Catalyzed DD fuel cycle with the transmutation of fusion-produced tritium into helium-3 is most feasible from the point of view of neutron production and tritium handling. The D-D fuel cycles seem to be less attractive compared to the Catalyzed DD. The p- 11 B and p- 6 Li fusion plasmas hardly attain the plasma Q value relevant to reactors. (author)

  1. Microwave Imaging of Human Forearms: Pilot Study and Image Enhancement

    Directory of Open Access Journals (Sweden)

    Colin Gilmore

    2013-01-01

    Full Text Available We present a pilot study using a microwave tomography system in which we image the forearms of 5 adult male and female volunteers between the ages of 30 and 48. Microwave scattering data were collected at 0.8 to 1.2 GHz with 24 transmitting and receiving antennas located in a matching fluid of deionized water and table salt. Inversion of the microwave data was performed with a balanced version of the multiplicative-regularized contrast source inversion algorithm formulated using the finite-element method (FEM-CSI. T1-weighted MRI images of each volunteer’s forearm were also collected in the same plane as the microwave scattering experiment. Initial “blind” imaging results from the utilized inversion algorithm show that the image quality is dependent on the thickness of the arm’s peripheral adipose tissue layer; thicker layers of adipose tissue lead to poorer overall image quality. Due to the exible nature of the FEM-CSI algorithm used, prior information can be readily incorporated into the microwave imaging inversion process. We show that by introducing prior information into the FEM-CSI algorithm the internal anatomical features of all the arms are resolved, significantly improving the images. The prior information was estimated manually from the blind inversions using an ad hoc procedure.

  2. A comparative study of Averrhoabilimbi extraction method

    Science.gov (United States)

    Zulhaimi, H. I.; Rosli, I. R.; Kasim, K. F.; Akmal, H. Muhammad; Nuradibah, M. A.; Sam, S. T.

    2017-09-01

    In recent year, bioactive compound in plant has become a limelight in the food and pharmaceutical market, leading to research interest to implement effective technologies for extracting bioactive substance. Therefore, this study is focusing on extraction of Averrhoabilimbi by different extraction technique namely, maceration and ultrasound-assisted extraction. Fewplant partsof Averrhoabilimbiweretaken as extraction samples which are fruits, leaves and twig. Different solvents such as methanol, ethanol and distilled water were utilized in the process. Fruit extractsresult in highest extraction yield compared to other plant parts. Ethanol and distilled water have significant role compared to methanol in all parts and both extraction technique. The result also shows that ultrasound-assisted extraction gave comparable result with maceration. Besides, the shorter period on extraction process gives useful in term of implementation to industries.

  3. Environmental Comparative Risk Assessment: A Case Study

    International Nuclear Information System (INIS)

    Ali, M.M.

    2007-01-01

    Health and environmental impacts associated with energy production and industrial activities as well as food production and agricultural activities have had great concern in the last decades. Early activities emerged in late 80s of the last century through an Inter- Agency project (lAEA, UNDY, WHO, ... ) on the comparative risk assessment from energy systems and industrial complexes. A work-shop on Risk Assessment and Management in large industrial areas was held in Alexandria Egypt on 20-33 Det 1993, sponsored by IAEA. Several conferences, experts work groups and workshops were held there of Recent trends in determining risks are: 1. Use of probabilistic risk assessment approach to identify hazardous activities and accident scenario. 2. development of data base on failure probabilities and appropriate physical models. 3. Development of related directives and regulations and criteria Comparative risk assessment case study as a tool for comparing risk is emphasized Criteria of exposure to human and ecological risks are addressed

  4. Comparing the Zeiss Callisto Eye and the Alcon Verion Image Guided System Toric Lens Alignment Technologies.

    Science.gov (United States)

    Hura, Arjan S; Osher, Robert H

    2017-07-01

    To compare the alignment meridian generated by the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA) and the Alcon Verion Image Guided System (Alcon Laboratories, Inc., Fort Worth, TX). In this retrospective comparative evaluation of technology, intraoperative images were captured at different steps in the same surgery, allowing the comparison of the guidance lines generated by the Verion system to the parallel guidance lines generated by the Callisto Eye system. Measurements of each hemi-meridian were quantified using Adobe Photoshop 2015 CC software (Adobe Systems, San Jose, CA). The numbers of degrees separating these alignment meridians were calculated, entered into a database, and analyzed. The authors found that of 98 captured images of 16 eyes, the two technologies were identical in 0 eyes (θ 1 = θ 2 = 0), similar by 3° in 52 (53%) captured images (θ 1 ≠ θ 2 ≠ 0), and different by at least 3° in 46 (47%) captured images (θ 1 ≠ θ 2 ≠ 0). The target meridians were superimposed, the target lines were minimally separated, and the target lines were dissimilar. It was noted that some intraoperative variation occurred from measurement to measurement. Within the small group of 16 cases of routine toric lens implantation in this study, the absolute average number of degrees of misalignment between the Verion and Callisto Eye systems was 3.355 for θ 1 and 3.838 for θ 2 . On average, the intraoperative variation termed "drift" was noted to be 3.963° for θ 1 , and 4.557° for θ 2 . The authors found that small deviations were frequent when comparing two sophisticated technologies. Although deviations greater than 3° occurred in less than 47% of captured images from 16 eyes, smaller but significant variations of less than 3° occurred in 53% of captured images from 16 eyes. It was rare to identify a large deviation. However, the authors identified "drift" in the same eye when measurements were taken at different times. The results indicate that the two

  5. Comparative study of the banana pulp browning process of 'Giant Dwarf' and FHIA-23 during fruit ripening based on image analysis and the polyphenol oxidase and peroxidase biochemical properties.

    Science.gov (United States)

    Escalante-Minakata, Pilar; Ibarra-Junquera, Vrani; Ornelas-Paz, José de Jesús; García-Ibáñez, Victoria; Virgen-Ortíz, José J; González-Potes, Apolinar; Pérez-Martínez, Jaime D; Orozco-Santos, Mario

    2018-01-01

    This work presents a novel method to associate the polyphenol oxidase (PPO) and the peroxidase (POD) activities with the ripening-mediated color changes in banana peel and pulp by computational image analysis. The method was used to follow up the de-greening of peel and browning of homogenized pulp from 'Giant Dwarf' (GD: Musa AAA, subgroup Cavendish) and FHIA-23 (tetraploid hybrid, AAAA) banana cultivars. In both cultivars, the color changes of peel during the ripening process clearly showed four stages, which were used to group the fruit into ripening stages. The PPO and POD were extracted from pulp of fruit at these ripening stages, precipitated, and partially purified by gel filtration chromatography. Moreover, the pulp browning was digitally monitored after homogenization for a span time of up to 120 min. The browning level was higher for GD than FHIA-23 tissues. This fact correlated with an 11.7-fold higher PPO activity in the GD cultivar, as compared with that of FHIA-23. POD activity was 8.1 times higher for GD as compared that that of FHIA-23.

  6. Comparative Study of Bancruptcy Prediction Models

    Directory of Open Access Journals (Sweden)

    Isye Arieshanti

    2013-09-01

    Full Text Available Early indication of bancruptcy is important for a company. If companies aware of  potency of their bancruptcy, they can take a preventive action to anticipate the bancruptcy. In order to detect the potency of a bancruptcy, a company can utilize a a model of bancruptcy prediction. The prediction model can be built using a machine learning methods. However, the choice of machine learning methods should be performed carefully. Because the suitability of a model depends on the problem specifically. Therefore, in this paper we perform a comparative study of several machine leaning methods for bancruptcy prediction. According to the comparative study, the performance of several models that based on machine learning methods (k-NN, fuzzy k-NN, SVM, Bagging Nearest Neighbour SVM, Multilayer Perceptron(MLP, Hybrid of MLP + Multiple Linear Regression, it can be showed that fuzzy k-NN method achieve the best performance with accuracy 77.5%

  7. Robust canonical correlations: A comparative study

    OpenAIRE

    Branco, JA; Croux, Christophe; Filzmoser, P; Oliveira, MR

    2005-01-01

    Several approaches for robust canonical correlation analysis will be presented and discussed. A first method is based on the definition of canonical correlation analysis as looking for linear combinations of two sets of variables having maximal (robust) correlation. A second method is based on alternating robust regressions. These methods axe discussed in detail and compared with the more traditional approach to robust canonical correlation via covariance matrix estimates. A simulation study ...

  8. Comparative Study on Water Impact Problem

    OpenAIRE

    Yang, Liang; Yang, Hao; Yan, Shiqiang; Ma, Qingwei; Bihnam, Maria

    2016-01-01

    This paper presents a comparative numerical study for the water impact problems due to dropping of triangular wedges or ship sections. In the numerical investigation, both the dynamic mesh technique and immersed boundary method adopting fixed Cartesian grids have been adopted in order to conform to the motion of the structure. For the former, a multiple-phase solver with the volume of fluid for identifying the free surface is implemented. In the simulation using this method, both the compress...

  9. Adding attenuation corrected images in myocardial perfusion imaging reduces the need for a rest study

    International Nuclear Information System (INIS)

    Trägårdh, Elin; Valind, Sven; Edenbrandt, Lars

    2013-01-01

    The American Society of Nuclear Cardiology and the Society of Nuclear Medicine conclude that incorporation of attenuation corrected (AC) images in myocardial perfusion scintigraphy (MPS) will improve diagnostic accuracy. The aim was to investigate the value of adding AC stress-only images for the decision whether a rest study is necessary or not. 1,261 patients admitted to 99m Tc MPS were studied. The stress studies were interpreted by two physicians who judged each study as “no rest study necessary” or “rest study necessary”, by evaluating NC stress-only and NC + AC stress-only images. When there was disagreement between the two physicians, a third physician evaluated the studies. Thus, agreement between 2 out of 3 physicians was evaluated. The physicians assessed 214 more NC + AC images than NC images as “no rest study necessary” (17% of the study population). The number of no-rest-study-required was significantly higher for NC + AC studies compared to NC studies (859 vs 645 cases (p < 0.0001). In the final report according to clinical routine, ischemia or infarction was reported in 23 patients, assessed as “no rest study necessary” (22 NC + AC cases; 8 NC cases), (no statistically significant difference). In 11 of these, the final report stated “suspected/possible ischemia or infarction in a small area”. Adding AC stress-only images to NC stress-only images reduce the number of unnecessary rest studies substantially

  10. Linear pneumatic motors – a comparative study

    Directory of Open Access Journals (Sweden)

    Deaconescu Tudor

    2017-01-01

    Full Text Available The paper presents a comparative study of the performance of single-acting cylinders, diaphragm cylinders and pneumatic muscles, and offers users information that allows the selection of an optimum technical solution. Such a study was necessary, in view of the numerous papers on pneumatic muscle applications found in literature, that assert the superiority of pneumatic muscles over other pneumatic linear motors in relation to quantities like dimensions, mass, developed force or energy-to-mass ratios, however without offering concrete data.

  11. A comparative study of two shovel designs.

    Science.gov (United States)

    Degani, A; Asfour, S S; Waly, S M; Koshy, J G

    1993-10-01

    In the present study a modified shovel design with two perpendicular shafts is presented. This modified, two-shaft shovel was compared with a regular shovel. The modified shovel was evaluated and tested in a controlled laboratory environment using surface electromyography recorded from the lumbar paraspinal muscles. The new shovel design was also tested in a field study using ratings of perceived exertion. The results indicate that there was a significant reduction in EMG values of the lumbar paraspinal muscles and a consistent reduction in perceived exertion ratings while the modified shovel was being used for removing dirt in digging trenches up to 90 cm in depth.

  12. [Nonprocess autism in children: comparative etiopathogenetic study].

    Science.gov (United States)

    Kagan, V E

    1979-01-01

    Etiopathogenesis of the childhood autism syndrome of a non-process nature is discussed on the basis of a comparative study of 156 children aged from 3 to 16 years. In the etiological complex there is a prevalence of early exogenous-organic noxious factors, which is reflected in disturbances of mental divelopment, maturation of the system of hemispheric pair work. The data of follow-up studies and treatment confirm a conclusion about a residual-organic basis in the syndrome of childhood autism.

  13. Pocahontas: Comparing the Disney Image with Historical Evidence

    Science.gov (United States)

    Golden, Margaret

    2006-01-01

    Fourth grade students "know about" Pocahontas, but is this knowledge based on historical fact, or on information from the media, specifically the Disney movies "Pocahontas" and "Pocahontas II"? To address this question within the context of the New York State Social Studies curriculum and the New York State English…

  14. PET imaging of α{sub 7} nicotinic acetylcholine receptors: a comparative study of [{sup 18}F]ASEM and [{sup 18}F]DBT-10 in nonhuman primates, and further evaluation of [{sup 18}F]ASEM in humans

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Ansel T.; Li, Songye; Zheng, Ming-Qiang; Lin, Shu-fei; Nabulsi, Nabeel; Holden, Daniel; Pracitto, Richard; Labaree, David; Ropchan, Jim; Esterlis, Irina; Cosgrove, Kelly P.; Carson, Richard E.; Huang, Yiyun [Yale University, PET Center, New Haven, CT (United States); Scheunemann, Matthias; Teodoro, Rodrigo; Deuther-Conrad, Winnie; Brust, Peter [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig (Germany)

    2017-06-15

    The α{sub 7} nicotinic acetylcholine receptor (nAChR) is implicated in many neuropsychiatric disorders, making it an important target for positron emission tomography (PET) imaging. The first aim of this work was to compare two α{sub 7} nAChRs PET radioligands, [{sup 18}F]ASEM 3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6-([{sup 18}F]fluorodibenzo[b,d]thiophene 5,5-dioxide) and [{sup 18}F]DBT-10 7-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-2-([{sup 18}F]fluorodibenzo[b,d]thiophene 5,5-dioxide), in nonhuman primates. The second aim was to assess further the quantification and test-retest variability of [{sup 18}F]ASEM in humans. PET scans with high specific activity [{sup 18}F]ASEM or [{sup 18}F]DBT-10 were acquired in three rhesus monkeys (one male, two female), and the kinetic properties of these radiotracers were compared. Additional [{sup 18}F]ASEM PET scans with blocking doses of nicotine, varenicline, and cold ASEM were acquired separately in two animals. Next, six human subjects (five male, one female) were imaged with [{sup 18}F]ASEM PET for 180 min, and arterial sampling was used to measure the parent input function. Different modeling approaches were compared to identify the optimal analysis method and scan duration for quantification of [{sup 18}F]ASEM distribution volume (V{sub T}). In addition, retest scans were acquired in four subjects (three male, one female), and the test-retest variability of V{sub T} was assessed. In the rhesus monkey brain [{sup 18}F]ASEM and [{sup 18}F]DBT-10 exhibited highly similar kinetic profiles. Dose-dependent blockade of [{sup 18}F]ASEM binding was observed, while administration of either nicotine or varenicline did not change [{sup 18}F]ASEM V{sub T}. [{sup 18}F]ASEM was selected for further validation because it has been used in humans. Accurate quantification of [{sup 18}F]ASEM V{sub T} in humans was achieved using multilinear analysis with at least 90 min of data acquisition, resulting in V{sub T} values ranging from 19.6 ± 2

  15. Detection ability of FDG-PET/CT comparing with other imaging modalities in multiple myeloma patients

    International Nuclear Information System (INIS)

    Chae, Min Jeong; Lee, Tae Hyun; Pai, Moon Sun; Cheon, Gi Jeong; Choi, Chang Woon; Lim, Sang Moo

    2007-01-01

    Multiple myeloma (MM) is characterized by bone marrow infiltration with malignant plasma cells. It is important to detect involving bone for diagnosis and management of MM. The aim of this study was to evaluate the diagnostic ability and limitation of 18F-FDG-PET/CT (PET/CT) comparing other imaging modalities (separated PET and CT, whole body plain X-ray (XR), bone scintigraphy (BS), and MRI) in MM. Twenty PET/CT scans were performed in 16 patients (M: F=6: 10, median age=59 y). PET/CT findings were compared with available other images (n of CT=21, XR=21, BS=8, and MRI=5). Concordance with more than 2 image modalities, laboratory data, symptom, and biopsies were used for diagnosis of detected lesions. PET/CT revealed 256 of total 287 sites (sensitivity, 89.2%; accuracy, 84.8%). The sensitivity and accuracy of separating PET, CT, and XR were 86.3%, 70.4%; 47.4%, 50.3%; and 72.8%, 72.4%, respectively. Available BS identified 67 of 202 sites (sensitivity, 33.2%; accuracy, 44.0%). MRI detected 20 of 24 sites (sensitivity, 83.3%; accuracy, 36.3%). False positive rate (FP) of PET, XR, and MRI was as high as 87.8%, 95.1%, and 100%. PET for rib lesion identified 9 of 10 patients (90.0%) but for skull lesion only 4 of 7 patients (57.2%) with underestimation. 5 patients in MRI showed diffuse marrow signal change but only 3 had marrow involvement. But PET/CT showed higher accuracy than MRI. PET/CT was the most useful tool for detecting involving bone of MM comparing with other imaging modalities. Moreover, PET/CT is expected to overcome the limitations for the small osteolytic bone lesions with diffuse FDG uptake on PET

  16. Comparative studies of brain activation with MEG and functional MRI

    International Nuclear Information System (INIS)

    George, J.S.; Aine, C.J.; Sanders, J.A.; Lewine, J.D.; Caprihan, A.

    1993-01-01

    The past two years have witnessed the emergence of MRI as a functional imaging methodology. Initial demonstrations involved the injection of a paramagnetic contrast agent and required ultrafast echo planar imaging capability to adequately resolve the passage of the injected bolus. By measuring the local reduction in image intensity due to magnetic susceptibility, it was possible to calculate blood volume, which changes as a function of neural activation. Later developments have exploited endogenous contrast mechanisms to monitor changes in blood volume or in venous blood oxygen content. Recently, we and others have demonstrated that it is possible to make such measurements in a clinical imager, suggesting that the large installed base of such machines might be utilized for functional imaging. Although it is likely that functional MRI (fMRI) will subsume some of the clinical and basic neuroscience applications now touted for MEG, it is also clear that these techniques offer different largely complementary, capabilities. At the very least, it is useful to compare and cross-validate the activation maps produced by these techniques. Such studies will be valuable as a check on results of neuromagnetic distributed current reconstructions and will allow better characterization of the relationship between neurophysiological activation and associated hemodynamic changes. A more exciting prospect is the development of analyses that combine information from the two modalities to produce a better description of underlying neural activity than is possible with either technique in isolation. In this paper we describe some results from initial comparative studies and outline several techniques that can be used to treat MEG and fMRI data within a unified computational framework

  17. A Comparative Study in Communication Texts & Theories

    Directory of Open Access Journals (Sweden)

    Mahdi Mohsenian Rad

    2011-04-01

    Full Text Available The present article is to study the characteristics and general nature of audience and is described it as "Audience phantasm" in developing countries. It firstly notes that there will be consequences such as audience distancing themselves from local and official media if policy makers and media officials' imaginations of audiences become far from related bare facts have happened in the era of global media and the nature of audiences. Knowing and analyzing the image of audiences presented in new communication theories. Accordingly, as the abovementioned authorities’ viewpoint of audiences exposed to media messages keeps distance from the true nature of media activities, media‐message receivers and their current position in the booming market of media, as termed by Mohsenyan Rad as “Message Bazaar”, there will possibly be disastrous social, cultural, political, and even economic consequences with regard to media uses.Then the history and definitions of “audience”, "uses & gratifications theory" and the concept of "Audience Phantasm" is described. After that, based on those and the increased options as well as the right of selecting of today-audience in the situation of message bazaar, as a result the characteristics of them are explained.

  18. Comparative Study of Daylighting Calculation Methods

    Directory of Open Access Journals (Sweden)

    Mandala Ariani

    2018-01-01

    Full Text Available The aim of this study is to assess five daylighting calculation method commonly used in architectural study. The methods used include hand calculation methods (SNI/DPMB method and BRE Daylighting Protractors, scale models studied in an artificial sky simulator and computer programs using Dialux and Velux lighting software. The test room is conditioned by the uniform sky conditions, simple room geometry with variations of the room reflectance (black, grey, and white color. The analyses compared the result (including daylight factor, illumination, and coefficient of uniformity value and examines the similarity and contrast the result different. The color variations trial is used to analyses the internally reflection factor contribution to the result.

  19. Imaging studies of crystalline arthritides

    Directory of Open Access Journals (Sweden)

    G. Garlaschi

    2012-01-01

    Full Text Available Gout, calcium pyrophosphate dihydrate (CPPD deposition disease, and calcium hydroxyapatite deposition disease (HADD are the three most common crystal-induced arthropathies. Multimodality imaging may help in their diagnosis, and is useful for a precise and comprehensive assessment and grading of the related osteoarticular damage. Plain film radiography, due to its low cost and wide availability, is the first imaging technique to be used in crystal deposition diseases, providing well-known and specific findings for CPPD deposition disease and HADD, while it may undergrade the early osteoarticular lesions in gouty patients. Ultrasonography (US is a radiation-free approach that accurately depicts crystal deposits in cartilage, peri- and intra-articular soft tissues, but it does not give a panoramic view of the affected joints. Cross-sectional imaging techniques can examine crystal deposits in the spine and axial joints. CT has the potential to distinguish monosodium urate (MSU crystals from calcium containing crystals, due to their different attenuation values. MRI may demonstrate synovitis, erosions and bone marrow edema in gouty patients and it may differentiate tophi from other soft tissue nodules due to its high contrast resolution and power of tissue characterization.

  20. Risk indices in comparative risk assessment studies

    International Nuclear Information System (INIS)

    Hubert, P.

    1984-01-01

    More than a decade ago the development of comparative risk assessment studies aroused overwhelming interest. There was no doubt that data on the health and safety aspects of energy systems would greatly benefit, or even end, the debate on nuclear energy. Although such attempts are still strongly supported, the rose-coloured expectations of the early days have faded. The high uncertainties, and the contradictory aspect, of the first results might explain this evolution. The loose connection between the range of computed risk indices and the questions on which the debate was focused is another reason for this decline in interest. Important research work is being carried out aiming at reducing the different kinds of uncertainties. Rather than the uncertainties, the paper considers the meaning of available risk indices and proposes more significant indices with respect to the goals of risk assessment. First, the indices which are of frequent use in comparative studies are listed. The stress is put on a French comparative study from which most examples are drawn. Secondly, the increase in magnitude of the indices and the decrease in the attributability of the risk to a given system is shown to be a consequence of the trend towards more comprehensive analyses. Thirdly, the ambiguity of such indices as the collective occupational risk is underlined, and a possible solution is suggested. Whenever risk assessments are related to pragmatic decision making problems it is possible to find satisfactory risk indices. The development of cost-effectiveness analyses and the proposals for quantitative safety goals clearly demonstrate this point. In the field of comparison of social impacts some proposals are made, but there remain some gaps still to be filled. (author)

  1. EFQPSK Versus CERN: A Comparative Study

    Science.gov (United States)

    Borah, Deva K.; Horan, Stephen

    2001-01-01

    This report presents a comparative study on Enhanced Feher's Quadrature Phase Shift Keying (EFQPSK) and Constrained Envelope Root Nyquist (CERN) techniques. These two techniques have been developed in recent times to provide high spectral and power efficiencies under nonlinear amplifier environment. The purpose of this study is to gain insights into these techniques and to help system planners and designers with an appropriate set of guidelines for using these techniques. The comparative study presented in this report relies on effective simulation models and procedures. Therefore, a significant part of this report is devoted to understanding the mathematical and simulation models of the techniques and their set-up procedures. In particular, mathematical models of EFQPSK and CERN, effects of the sampling rate in discrete time signal representation, and modeling of nonlinear amplifiers and predistorters have been considered in detail. The results of this study show that both EFQPSK and CERN signals provide spectrally efficient communications compared to filtered conventional linear modulation techniques when a nonlinear power amplifier is used. However, there are important differences. The spectral efficiency of CERN signals, with a small amount of input backoff, is significantly better than that of EFQPSK signals if the nonlinear amplifier is an ideal clipper. However, to achieve such spectral efficiencies with a practical nonlinear amplifier, CERN processing requires a predistorter which effectively translates the amplifier's characteristics close to those of an ideal clipper. Thus, the spectral performance of CERN signals strongly depends on the predistorter. EFQPSK signals, on the other hand, do not need such predistorters since their spectra are almost unaffected by the nonlinear amplifier, Ibis report discusses several receiver structures for EFQPSK signals. It is observed that optimal receiver structures can be realized for both coded and uncoded EFQPSK

  2. CURRICULAR OFFER INFLUENCING STUDENTS’ SATISFACTION: COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Oana DUMITRASCU

    2014-11-01

    Full Text Available The main objective of the study is the determination of students’ satisfaction regarding curricular activities. The study has been accomplished using the qualitative and quantitative research, using the bibliographic study, various secondary sources and different primary sources. The study is developed with a marketing research and accomplished using the survey method. 699 students from four universities have been questioned. Due to a comparative study the University of Applied Sciences Worms, University of Applied Sciences Wiesbaden Rüsselsheim, University of Applied Sciences Frankfurt am Main and Nürtingen-Geislingen University have been analysed and their similarities and differences have been identified. The collected data, based on the established sample, is evaluated through univariate and bivariate analysis. In accordance with the evaluated sample, specific gaps from each region are identified regarding the curricular offer of the analysed universities. As a result to the conducted study, recommendations for the University of Applied Sciences Worms regarding the student’s satisfaction concerning the curricular offer are presented.

  3. New tools for comparing microscopy images: quantitative analysis of cell types in Bacillus subtilis.

    Science.gov (United States)

    van Gestel, Jordi; Vlamakis, Hera; Kolter, Roberto

    2015-02-15

    Fluorescence microscopy is a method commonly used to examine individual differences between bacterial cells, yet many studies still lack a quantitative analysis of fluorescence microscopy data. Here we introduce some simple tools that microbiologists can use to analyze and compare their microscopy images. We show how image data can be converted to distribution data. These data can be subjected to a cluster analysis that makes it possible to objectively compare microscopy images. The distribution data can further be analyzed using distribution fitting. We illustrate our methods by scrutinizing two independently acquired data sets, each containing microscopy images of a doubly labeled Bacillus subtilis strain. For the first data set, we examined the expression of srfA and tapA, two genes which are expressed in surfactin-producing and matrix-producing cells, respectively. For the second data set, we examined the expression of eps and tapA; these genes are expressed in matrix-producing cells. We show that srfA is expressed by all cells in the population, a finding which contrasts with a previously reported bimodal distribution of srfA expression. In addition, we show that eps and tapA do not always have the same expression profiles, despite being expressed in the same cell type: both operons are expressed in cell chains, while single cells mainly express eps. These findings exemplify that the quantification and comparison of microscopy data can yield insights that otherwise would go unnoticed. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. Significant improvement in synovitis, osteitis, and bone erosion following golimumab and methotrexate combination therapy as compared with methotrexate alone: A magnetic resonance imaging study of 318 methotrexate-naive rheumatoid arthritis patients

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Emery, Paul; Conaghan, Philip G

    2011-01-01

    To evaluate the effects of golimumab on inflammation/structural damage detected by magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA).......To evaluate the effects of golimumab on inflammation/structural damage detected by magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA)....

  5. A comparative study of teenage pregnancy.

    Science.gov (United States)

    Mahavarkar, S H; Madhu, C K; Mule, V D

    2008-08-01

    Teenage pregnancy is a global problem and is considered a high-risk group, in spite of conflicting evidence. Our objective was to compare obstetric outcomes of pregnancy in teenagers and older women. This was a retrospective study of case records of pregnancies from August 2000 to July 2001. Girls aged pregnancy outcomes in older women (19-35 years) in the same hospital. The study took place in the Government General Hospital, Sangli, India, a teaching hospital in rural India, with an annual delivery rate of over 3,500. A total of 386 teenage pregnancies were compared with pregnancies in 3,326 older women. Socioeconomic data, age, number of pregnancies, antenatal care and complications, mode of delivery, and neonatal outcomes were considered. The incidence of teenage pregnancy in the study was 10%. A significant proportion of teenage pregnant mothers were in their first pregnancies. The teenage mothers were nearly three times more at risk of developing anaemia (OR = 2.83, 95% CI = 2.2-3.7, p Teenage mothers were twice as likely to develop hypertensive problems in pregnancy (OR = 2.2, 95% CI = 1.5-3.2, p teenage pregnancies are still a common occurrence in rural India in spite of various legislations and government programmes and teenage pregnancy is a risk factor for poor obstetric outcome in rural India. Cultural practices, poor socioeconomic conditions, low literacy rate and lack of awareness of the risks are some of the main contributory factors. Early booking, good care during pregnancy and delivery and proper utilisation of contraceptive services can prevent the incidence and complications in this high-risk group.

  6. Reflex sympathetic dystrophy syndrome: MR imaging study

    International Nuclear Information System (INIS)

    Masciocchi, C.; Fascetti, E.; Bonanni, G.; Calvisi, V.; Buoni, C.; Passariello, R.

    1987-01-01

    Reflex sympathetic dystrophy syndrome (RSDS) is characterized by pain, swelling, and limitation of motion. The etiology and pathophysiology mechanism have not yet been identified. We considered eight patients with clinical signs of RSDS, in five cases located at the knee joint and in three cases in the hip. In all cases conventional radiography and radionuclide bone scanning were performed before MR imaging. Conventional radiography was negative in three cases while scintigraphy demonstrated the lesion in all patients. MR imaging showed an area of low intensity signal on T1-weighted scans and an increased signal intensity on T2-weighted images. This area is located at the bone marrow and its regular and homogeneous. This specific finding on MR images is due to reflect edema by hyperemia of the bone marrow. The MR imaging diagnosis was confirmed on clinical and radiological follow-up. MR imaging can have a role in the differential diagnosis when other studies are nondiagnostic or nonspecific for RSDS

  7. SP-ECT imaging and its physical study

    International Nuclear Information System (INIS)

    Kinoshita, Fujimi

    1983-01-01

    Recently, more than a hundred hospitals are provided with SPECT system for clinical examination in Japan. However, a standardization of measuring method and performance test of the systems is ont yet made. We have been studying some basic problems of SPECT system with special phantoms originaly designed by ourselves. We got a conclusion that a standardized phantom is necessary for comparing performances between SPECT systems. In clinical experiences with 3,332 cases, we think that SPECT image combined with conventional image presents much more informations for accurate diagnosis, especially in brain, bone and tumor imagings. Synthesized image of SPECT and XCT, double tracer image and transmission image are useful to visualize the body contour and the clinical diagnosis. (author)

  8. A comparative study of bike lane injuries.

    Science.gov (United States)

    Wee, Jung Hee; Park, Jeong Ho; Park, Kyu Nam; Choi, Seung Pill

    2012-02-01

    Because of the increased number of bicycle riders and governmental promotions, a recent increase in the construction of bicycle lanes has occurred. We aimed to characterize injuries specific to bicycle lane accidents by comparing them with injuries that occurred on regular roadways. On the basis of our findings, we provide suggestions on proper preventive strategies. We performed a retrospective study on 408 cases obtained between January 1, 2009, and December 31, 2010. Of these cases, 387 met the criterion that the location of the injury could be confirmed by telephone or via review of the patient's chart. Data regarding age, gender, Injury Severity Score, time of the accident, location of the accident, and other characteristics were collected. Data were analyzed using SPSS 12.0K. Of the 387 cases, 204 (52.7%) patients were injured in bicycle lanes and 183 (47.3%) were injured on regular roadways. Comparing cases of bicycle lane injuries and non-bicycle lane injuries, there were no differences in age, day of the week, season, or the time at which the accident occurred. Bicycle helmets were used more frequently in bicycle lane injuries (33.2% vs. 13.7%; p cases, falls (42.6%) and collisions with other vehicles (39.3%) were the most common causes of injury. Although the severity of injuries was slightly lower in bicycle lane cases, it was not significantly lower than non-bicycle lane cases. Although people are increasingly using bicycle lanes for safety, this study shows that they are not definitively safer. Therefore, improvements in the policies related to implementing bicycle lane safety are needed, for example, by enforcing the use of protective gear or preventing the use of bicycle lanes by pedestrians. More safety education programs are also needed. III.

  9. Laproscopic versus open appendectomy: A comparative study

    International Nuclear Information System (INIS)

    Shirazi, B.; Naureen Ali, N.; Shamim, M.S.

    2010-01-01

    Objective: To compare the results of open with laparoscopic appendectomy in terms of postoperative pain, rate of wound infection and hospital stay. Methods: This quasi-experimental study was conducted in Department of Surgery, Ziauddin University Hospital, Karachi, over a period of six months. Patients undergoing surgery for acute appendicitis were randomly assigned into one of the two groups (A or B) after obtaining written and informed consent. In Group-A patients underwent open appendectomy and in Group B laparoscopic appendectomy was performed. Post operatively pain chart and wound infection was recorded and, at the time of discharge, number of days in hospital was calculated. Result: Sixty patients (38 male, 22 female), with clinical diagnosis of acute appendicitis based on Alvarado score of six and above, were included in the study. They were randomized into 2 groups of A and B with 30 patients in each group. Group-A comprised open appendectomy procedure and Group-B comprised laparoscopic appendectomy. Mean comparison of postoperative pain by visual analogue scale, was significantly low in Group B, compared with Group A, on day 0, 1 and 2. Number of days in Hospital was 4.1 +- 0.8 days in Group A and 1.5 +- 0.06 days in Group B. None of the patients in Group B, while 8 (26.67%) patients in-Group A, developed postoperative wound infection at 1 week follow up. Conclusion: Laparoscopic appendectomy is safe and effective. Wound infection and postoperative pain is significantly lower after this mode of surgery. (author)

  10. Sedation with nitrous oxide compared with no sedation during catheterization for urologic imaging in children

    International Nuclear Information System (INIS)

    Zier, Judith L.; Kvam, Kathryn A.; Kurachek, Stephen C.; Finkelstein, Marsha

    2007-01-01

    Various strategies to mitigate children's distress during voiding cystourethrography (VCUG) have been described. Sedation with nitrous oxide is comparable to that with oral midazolam for VCUG, but a side-by-side comparison of nitrous oxide sedation and routine care is lacking. The effects of sedation/analgesia using 70% nitrous oxide and routine care for VCUG and radionuclide cystography (RNC) were compared. A sample of 204 children 4-18 years of age scheduled for VCUG or RNC with sedation or routine care were enrolled in this prospective study. Nitrous oxide/oxygen (70%/30%) was administered during urethral catheterization to children in the sedated group. The outcomes recorded included observed distress using the Brief Behavioral Distress Score, self-reported pain, and time in department. The study included 204 patients (99 nonsedated, 105 sedated) with a median age of 6.3 years (range 4.0-15.2 years). Distress and pain scores were greater in nonsedated than in sedated patients (P < 0.001). Time in department was longer in the sedated group (90 min vs. 30 min); however, time from entry to catheterization in a non-imaging area accounted for most of the difference. There was no difference in radiologic imaging time. Sedation with nitrous oxide is effective in reducing distress and pain during catheterization for VCUG or RNC in children. (orig.)

  11. Comparative X-ray investigation of lateral and anterior-posterior ankle-joint images - comparison with pathological and anatomical findings concerning lateral ankle-joint lesions and their clinical importance, studied in a special type of holding device

    International Nuclear Information System (INIS)

    John, F.

    1982-01-01

    The study reports on a possibility to interpret the relation of the different bone structures of the upper ankle-joint to one another in the X-ray picture without using contrast media. Modern funtional diagnostic methods increasingly make use of X-ray pictures taken in fixed position. It seems useful to standardize such X-ray images of the ankle-joint in order to make them reproducible. The author developed a device that would suit these purposes. A diagnosis required the reproduction of the accidental mechanism. The clinical symptoms do not permit to clearly state the extent of the lesion of the ligaments. The results of the post-operative follow-up examinations confirm the urgent necessity of the standardized diagnostic method presented and the success of the therapy applied. The presented X-ray method permits safe diagnosis of ruptures of the ligaments. Location of a certain rupture is not possible with the fixed-position X-ray screening. For a clear assessment of lesions of the ligaments at the lateral ankle-joint, X-ray pictures must be taken both in the anterior-posterior path of rays and in the lateral one. A normal result in the lateral path of rays does not exclude a pathologic result in the anterior-posterior path of rays, and vice versa. (orig./MG) [de

  12. Comparative studies of groundwater vulnerability assessment

    Science.gov (United States)

    Maria, Rizka

    2018-02-01

    Pollution of groundwater is a primary issue because aquifers are susceptible to contamination from land use and anthropogenic impacts. Groundwater susceptibility is intrinsic and specific. Intrinsic vulnerability refers to an aquifer that is susceptible to pollution and to the geological and hydrogeological features. Vulnerability assessment is an essential step in assessing groundwater contamination. This approach provides a visual analysis for helping planners and decision makers to achieve the sustainable management of water resources. Comparative studies are applying different methodologies to result in the basic evaluation of the groundwater vulnerability. Based on the comparison of methods, there are several advantages and disadvantages. SI can be overlaid on DRASTIC and Pesticide DRASTIC to extract the divergence in sensitivity. DRASTIC identifies low susceptibility and underestimates the pollution risk while Pesticide DRASTIC and SI represents better risk and is recommended for the future. SINTACS method generates very high vulnerability zones with surface waters and aquifer interactions. GOD method could be adequate for vulnerability mapping in karstified carbonate aquifers at small-moderate scales, and EPIK method can be used for large scale. GOD method is suitable for designing large area such as land management while DRASTIC has good accuracy and more real use in geoenvironmental detailed studies.

  13. Magnetic resonance imaging findings compared with histological findings of the labrum in hip osteoarthritis

    International Nuclear Information System (INIS)

    Kanezaki, Shiho; Nakamura, Shigeru; Matsushita, Takashi; Yamamoto, Asako; Osawa, Marie

    2015-01-01

    Patients with disorders such as acetabular dysplasia or femoroacetabular impingement are at risk of developing hip osteoartbritis. Assessment of the cartilage and labrum in the hip joint based on magnetic resonance imaging (MRI) has been challenging because of the low signal-to-noise ratio (SNR) due to its deep location, ball and socket structure, and small volume of those structures compared with the whole joint size. To achieve better imaging assessment, direct MR. arthrography (d-MRA) and other techniques such as T2* mapping, T2 mapping, Tlrho, and delayed gadolinium-enhanced MRI (dGEMRIC) have been developed along with the increasing use of high-field MRI. In patients with no apparent osteoarthritic changes such as joint space narrowing or osteophyte and subchondral cyst formation on radiographs, these techniques can detect early cartilage or labral damage. A recently developed semiquantitative MRI-based scoring system for hip osteoarthritis includes evaluation of the labrum, and its application as a potential therapeutic monitoring tool is anticipated. The labrum shows pathological changes such as macroscopic hypertrophy and histological degeneration in hip osteoartbritis, but the pathological background is not well understood when evaluated by MRI. Kubo et al. compared radial MRI findings with histological changes of the labrum in ll hips with osteoarthritis using 1.5-T MRJ and found that fibrous separation and mucoid deposition occurred in the labrum with a ''diffuse high signal'' or ''obscure'' pattern. However, to the best of our knowledge, no studies have demonstrated a correlation between MRI fmdings and histological evidence of the severity of degeneration of the labrum. We hypothesized that radially reconstructed images of the acetabular labrum acquired by 3-T MRI can depict degenerative changes of the labrum. In this study, we sought to determine the correlation between MRI and histological findings of the

  14. Magnetic resonance imaging findings compared with histological findings of the labrum in hip osteoarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Kanezaki, Shiho; Nakamura, Shigeru; Matsushita, Takashi [Teikyo University School of Medicine, Department of Orthopaedic Surgery, Itabashi-ku, Tokyo (Japan); Yamamoto, Asako; Osawa, Marie [Teikyo University School of Medicine, Department of Radiology, Itabashi-ku, Tokyo (Japan)

    2015-06-01

    Patients with disorders such as acetabular dysplasia or femoroacetabular impingement are at risk of developing hip osteoartbritis. Assessment of the cartilage and labrum in the hip joint based on magnetic resonance imaging (MRI) has been challenging because of the low signal-to-noise ratio (SNR) due to its deep location, ball and socket structure, and small volume of those structures compared with the whole joint size. To achieve better imaging assessment, direct MR. arthrography (d-MRA) and other techniques such as T2* mapping, T2 mapping, Tlrho, and delayed gadolinium-enhanced MRI (dGEMRIC) have been developed along with the increasing use of high-field MRI. In patients with no apparent osteoarthritic changes such as joint space narrowing or osteophyte and subchondral cyst formation on radiographs, these techniques can detect early cartilage or labral damage. A recently developed semiquantitative MRI-based scoring system for hip osteoarthritis includes evaluation of the labrum, and its application as a potential therapeutic monitoring tool is anticipated. The labrum shows pathological changes such as macroscopic hypertrophy and histological degeneration in hip osteoartbritis, but the pathological background is not well understood when evaluated by MRI. Kubo et al. compared radial MRI findings with histological changes of the labrum in ll hips with osteoarthritis using 1.5-T MRJ and found that fibrous separation and mucoid deposition occurred in the labrum with a ''diffuse high signal'' or ''obscure'' pattern. However, to the best of our knowledge, no studies have demonstrated a correlation between MRI fmdings and histological evidence of the severity of degeneration of the labrum. We hypothesized that radially reconstructed images of the acetabular labrum acquired by 3-T MRI can depict degenerative changes of the labrum. In this study, we sought to determine the correlation between MRI and histological findings of the

  15. Large-field image intensifiers versus conventional chest radiography: ROC study with simulated interstitial disease

    International Nuclear Information System (INIS)

    Winter, L.H.L.; Chakraborty, D.P.; Waes, P.F.G.M.

    1988-01-01

    Two image intensifier tubes have recently been introduced whose large imaging area makes them suitable for chest imaging (Phillips Pulmodiagnost TLX slit II and Siemens TX 57 large entrance field II). Both modalities present a 10 x 10-cm hard copy image to the radiologist. A receiver operating characteristic (ROC) curve study with simulated interstitial disease was performed to compare the image quality of these image intensifiers with conventional chest images. The relative ranking in terms of decreasing ROC areas was Siemens, conventional, and Philips. Compared with conventional imaging, none of the differences in ROC curve area were statistically significant at the 5% level

  16. Image quality characteristics of a novel colour scanning digital ophthalmoscope (SDO) compared with fundus photography.

    Science.gov (United States)

    Strauss, Rupert W; Krieglstein, Tina R; Priglinger, Siegfried G; Reis, Werner; Ulbig, Michael W; Kampik, Anselm; Neubauer, Aljoscha S

    2007-11-01

    To establish a set of quality parameters for grading image quality and apply those to evaluate the fundus image quality obtained by a new scanning digital ophthalmoscope (SDO) compared with standard slide photography. On visual analogue scales a total of eight image characteristics were defined: overall quality, contrast, colour brilliance, focus (sharpness), resolution and details, noise, artefacts and validity of clinical assessment. Grading was repeated after 4 months to assess repeatability. Fundus images of 23 patients imaged digitally by SDO and by Zeiss 450FF fundus camera using Kodak film were graded side-by-side by three graders. Lens opacity was quantified with the Interzeag Lens Opacity Meter 701. For all of the eight scales of image quality, good repeatability within the graders (mean Kendall's W 0.69) was obtained after 4 months. Inter-grader agreement ranged between 0.31 and 0.66. Despite the SDO's limited nominal image resolution of 720 x 576 pixels, the Zeiss FF 450 camera performed better in only two of the subscales - noise (p = 0.001) and artefacts (p = 0.01). Lens opacities significantly influenced only the two subscales 'resolution' and 'details', which deteriorated with increasing media opacities for both imaging systems. Distinct scales to grade image characteristics of different origin were developed and validated. Overall SDO digital imaging was found to provide fundus pictures of a similarly high level of quality as expert photography on slides.

  17. Hip imaging of avascular necrosis at 7 Tesla compared with 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Theysohn, J.M.; Kraff, O.; Theysohn, N.; Orzada, S.; Lauenstein, T.C. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Institute for Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Landgraeber, S. [University Hospital Essen, Department of Orthopedic Surgery, Essen (Germany); Ladd, M.E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); German Cancer Research Center, Department of Medical Physics in Radiology, Heidelberg (Germany)

    2014-05-15

    To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities. Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data. 7-T imaging of the femoral joints, as well as 3-T imaging, achieved ''good'' to ''very good'' quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS > 2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9-4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1-2.9); to a lesser extent also GRE sequences (7 T: 2.9-3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2-2.6) and cartilage defects (2.5-3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5). 7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight

  18. Hip imaging of avascular necrosis at 7 Tesla compared with 3 Tesla

    International Nuclear Information System (INIS)

    Theysohn, J.M.; Kraff, O.; Theysohn, N.; Orzada, S.; Lauenstein, T.C.; Landgraeber, S.; Ladd, M.E.

    2014-01-01

    To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities. Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data. 7-T imaging of the femoral joints, as well as 3-T imaging, achieved ''good'' to ''very good'' quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS > 2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9-4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1-2.9); to a lesser extent also GRE sequences (7 T: 2.9-3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2-2.6) and cartilage defects (2.5-3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5). 7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight advantages in contrast detail (cartilage defects

  19. SU-E-J-89: Comparative Analysis of MIM and Velocity’s Image Deformation Algorithm Using Simulated KV-CBCT Images for Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Cline, K; Narayanasamy, G; Obediat, M; Stanley, D; Stathakis, S; Kirby, N [University of Texas Health Science Center at San Antonio, Cancer Therapy and Research Center, San Antonio, TX (United States); Kim, H [University of California San Francisco, San Francisco, CA (United States)

    2015-06-15

    Purpose: Deformable image registration (DIR) is used routinely in the clinic without a formalized quality assurance (QA) process. Using simulated deformations to digitally deform images in a known way and comparing to DIR algorithm predictions is a powerful technique for DIR QA. This technique must also simulate realistic image noise and artifacts, especially between modalities. This study developed an algorithm to create simulated daily kV cone-beam computed-tomography (CBCT) images from CT images for DIR QA between these modalities. Methods: A Catphan and physical head-and-neck phantom, with known deformations, were used. CT and kV-CBCT images of the Catphan were utilized to characterize the changes in Hounsfield units, noise, and image cupping that occur between these imaging modalities. The algorithm then imprinted these changes onto a CT image of the deformed head-and-neck phantom, thereby creating a simulated-CBCT image. CT and kV-CBCT images of the undeformed and deformed head-and-neck phantom were also acquired. The Velocity and MIM DIR algorithms were applied between the undeformed CT image and each of the deformed CT, CBCT, and simulated-CBCT images to obtain predicted deformations. The error between the known and predicted deformations was used as a metric to evaluate the quality of the simulated-CBCT image. Ideally, the simulated-CBCT image registration would produce the same accuracy as the deformed CBCT image registration. Results: For Velocity, the mean error was 1.4 mm for the CT-CT registration, 1.7 mm for the CT-CBCT registration, and 1.4 mm for the CT-simulated-CBCT registration. These same numbers were 1.5, 4.5, and 5.9 mm, respectively, for MIM. Conclusion: All cases produced similar accuracy for Velocity. MIM produced similar values of accuracy for CT-CT registration, but was not as accurate for CT-CBCT registrations. The MIM simulated-CBCT registration followed this same trend, but overestimated MIM DIR errors relative to the CT

  20. SU-E-J-89: Comparative Analysis of MIM and Velocity’s Image Deformation Algorithm Using Simulated KV-CBCT Images for Quality Assurance

    International Nuclear Information System (INIS)

    Cline, K; Narayanasamy, G; Obediat, M; Stanley, D; Stathakis, S; Kirby, N; Kim, H

    2015-01-01

    Purpose: Deformable image registration (DIR) is used routinely in the clinic without a formalized quality assurance (QA) process. Using simulated deformations to digitally deform images in a known way and comparing to DIR algorithm predictions is a powerful technique for DIR QA. This technique must also simulate realistic image noise and artifacts, especially between modalities. This study developed an algorithm to create simulated daily kV cone-beam computed-tomography (CBCT) images from CT images for DIR QA between these modalities. Methods: A Catphan and physical head-and-neck phantom, with known deformations, were used. CT and kV-CBCT images of the Catphan were utilized to characterize the changes in Hounsfield units, noise, and image cupping that occur between these imaging modalities. The algorithm then imprinted these changes onto a CT image of the deformed head-and-neck phantom, thereby creating a simulated-CBCT image. CT and kV-CBCT images of the undeformed and deformed head-and-neck phantom were also acquired. The Velocity and MIM DIR algorithms were applied between the undeformed CT image and each of the deformed CT, CBCT, and simulated-CBCT images to obtain predicted deformations. The error between the known and predicted deformations was used as a metric to evaluate the quality of the simulated-CBCT image. Ideally, the simulated-CBCT image registration would produce the same accuracy as the deformed CBCT image registration. Results: For Velocity, the mean error was 1.4 mm for the CT-CT registration, 1.7 mm for the CT-CBCT registration, and 1.4 mm for the CT-simulated-CBCT registration. These same numbers were 1.5, 4.5, and 5.9 mm, respectively, for MIM. Conclusion: All cases produced similar accuracy for Velocity. MIM produced similar values of accuracy for CT-CT registration, but was not as accurate for CT-CBCT registrations. The MIM simulated-CBCT registration followed this same trend, but overestimated MIM DIR errors relative to the CT

  1. Comparing Individual Tree Segmentation Based on High Resolution Multispectral Image and Lidar Data

    Science.gov (United States)

    Xiao, P.; Kelly, M.; Guo, Q.

    2014-12-01

    This study compares the use of high-resolution multispectral WorldView images and high density Lidar data for individual tree segmentation. The application focuses on coniferous and deciduous forests in the Sierra Nevada Mountains. The tree objects are obtained in two ways: a hybrid region-merging segmentation method with multispectral images, and a top-down and bottom-up region-growing method with Lidar data. The hybrid region-merging method is used to segment individual tree from multispectral images. It integrates the advantages of global-oriented and local-oriented region-merging strategies into a unified framework. The globally most-similar pair of regions is used to determine the starting point of a growing region. The merging iterations are constrained within the local vicinity, thus the segmentation is accelerated and can reflect the local context. The top-down region-growing method is adopted in coniferous forest to delineate individual tree from Lidar data. It exploits the spacing between the tops of trees to identify and group points into a single tree based on simple rules of proximity and likely tree shape. The bottom-up region-growing method based on the intensity and 3D structure of Lidar data is applied in deciduous forest. It segments tree trunks based on the intensity and topological relationships of the points, and then allocate other points to exact tree crowns according to distance. The accuracies for each method are evaluated with field survey data in several test sites, covering dense and sparse canopy. Three types of segmentation results are produced: true positive represents a correctly segmented individual tree, false negative represents a tree that is not detected and assigned to a nearby tree, and false positive represents that a point or pixel cluster is segmented as a tree that does not in fact exist. They respectively represent correct-, under-, and over-segmentation. Three types of index are compared for segmenting individual tree

  2. Automated Diabetic Retinopathy Image Assessment Software: Diagnostic Accuracy and Cost-Effectiveness Compared with Human Graders.

    Science.gov (United States)

    Tufail, Adnan; Rudisill, Caroline; Egan, Catherine; Kapetanakis, Venediktos V; Salas-Vega, Sebastian; Owen, Christopher G; Lee, Aaron; Louw, Vern; Anderson, John; Liew, Gerald; Bolter, Louis; Srinivas, Sowmya; Nittala, Muneeswar; Sadda, SriniVas; Taylor, Paul; Rudnicka, Alicja R

    2017-03-01

    With the increasing prevalence of diabetes, annual screening for diabetic retinopathy (DR) by expert human grading of retinal images is challenging. Automated DR image assessment systems (ARIAS) may provide clinically effective and cost-effective detection of retinopathy. We aimed to determine whether ARIAS can be safely introduced into DR screening pathways to replace human graders. Observational measurement comparison study of human graders following a national screening program for DR versus ARIAS. Retinal images from 20 258 consecutive patients attending routine annual diabetic eye screening between June 1, 2012, and November 4, 2013. Retinal images were manually graded following a standard national protocol for DR screening and were processed by 3 ARIAS: iGradingM, Retmarker, and EyeArt. Discrepancies between manual grades and ARIAS results were sent to a reading center for arbitration. Screening performance (sensitivity, false-positive rate) and diagnostic accuracy (95% confidence intervals of screening-performance measures) were determined. Economic analysis estimated the cost per appropriate screening outcome. Sensitivity point estimates (95% confidence intervals) of the ARIAS were as follows: EyeArt 94.7% (94.2%-95.2%) for any retinopathy, 93.8% (92.9%-94.6%) for referable retinopathy (human graded as either ungradable, maculopathy, preproliferative, or proliferative), 99.6% (97.0%-99.9%) for proliferative retinopathy; Retmarker 73.0% (72.0 %-74.0%) for any retinopathy, 85.0% (83.6%-86.2%) for referable retinopathy, 97.9% (94.9%-99.1%) for proliferative retinopathy. iGradingM classified all images as either having disease or being ungradable. EyeArt and Retmarker saved costs compared with manual grading both as a replacement for initial human grading and as a filter prior to primary human grading, although the latter approach was less cost-effective. Retmarker and EyeArt systems achieved acceptable sensitivity for referable retinopathy when compared

  3. Comparative economic analysis: Anaerobic digester case study

    International Nuclear Information System (INIS)

    Lusk, P.D.

    1991-01-01

    An economic guide is developed to assess the value of anaerobic digesters used on dairy farms. Two varieties of anaerobic digesters, a conventional mixed-tank mesophilic and an innovative earthen psychrophilic, are comparatively evaluated using a cost-effectiveness index. The two case study examples are also evaluated using three other investment merit statistics: simple payback period, net present value, and internal rate of return. Life-cycle savings are estimated for both varieties, with sensitivities considered for investment risk. The conclusion is that an earthen psychrophilic digester can have a significant economic advantage over a mixed-tank mesophilic digester because of lower capital cost and reduced operation and maintenance expenses. Because of this economic advantage, additional projects are being conducted in North Carolina to increase the rate of biogas utilization. The initial step includes using biogas for milk cooling at the dairy farm where the existing psychrophilic digester is located. Further, a new project is being initiated for electricity production with thermal reclaim at a swine operation

  4. Comparative studies of stellarator and tokamak transport

    Energy Technology Data Exchange (ETDEWEB)

    Stroth, U; Burhenn, R; Geiger, J; Giannone, L.; Hartfuss, H J; Kuehner, G; Ledl, L; Simmet, E E; Walter, H [Max-Planck-Inst. fuer Plasmaphysik, IPP-Euratom Association, Garching (Germany); ECRH Team; W7-AS Team

    1997-09-01

    Transport properties in the W7-AS stellarator and in tokamaks are compared. The parameter dependences and the absolute values of the energy confinement time are similar. Indications are found that the density dependence, which is usually observed in stellarator confinement, can vanish above a critical density. The density dependence in stellarators seems to be similar to that in the linear ohmic confinement regime, which, in small tokamaks, extends to high density values, too. Because of the similarity in the gross confinement properties, transport in stellarators and tokamaks should not be dominated by the parameters which are very different in the two concepts, i.e. magnetic shear, major rational values of the rotational transform and plasma current. A difference in confinement is that there exists evidence for pinches in the particle and, possibly, energy transport channels in tokamaks whereas in stellarators no pinches have been observed, so far. In order to study the effect of plasma current and toroidal electric fields, stellarator discharges were carried out with an increasing amount of plasma current. From these experiments, no clear evidence of a connection of pinches with these parameters is found. The transient response in W7-AS plasmas can be described in terms of a non-local model. As in tokamaks, also cold pulse experiments in W7-AS indicate the importance of non-local transport. (author). 8 refs, 5 figs.

  5. COMPARATIVE STUDY ON ACCOUNTING AND FISCAL AMORTIZATION

    Directory of Open Access Journals (Sweden)

    MARIANA GURAU

    2012-05-01

    Full Text Available Placed in the international trend, Romanian accounting had experienced various changes, especially as regards of progress on disconnection between accounting and fiscality. In the present, fiscal rules should not have any role in accounting decisions, because accounting rules are applied to produce accounting information that is useful in making decisions and to provide a "true and fair view" upon financial reality of the entity. However, the barrier in the habit of accounting to thinking for fiscal point of view all economic transactions remains insurmountable, yet. Starting from this perspective on disconnection between accounting and fiscality would mean that amortization recorded in the accounting, as a result of management policy, to be different from fiscality amortization, to calculate income tax. Although formally accepted, disconnect between accounting and fiscality continues to meet many difficulties. In this sense, it is usual in practice to use the same method of amortization for accounting purposes and for fiscal purposes to prevent complications of double track amortization and prevent wandering in the rules in this field. Accounting rule is deliberately eluded in favor of the fiscal rules. This is the reason we proposed to make in this paper a comparative study between norms and rules on accounting and fiscal amortization, paper in which we intend to show the benefits of applying accounting and fiscal rules separately.

  6. Comparative study on Charpy specimen reconstitution techniques

    International Nuclear Information System (INIS)

    Bourdiliau, B.; Decroix, G.-M.; Averty, X.; Wident, P.; Bienvenu, Y.

    2011-01-01

    Highlights: → Welding processes are used to reconstitute previously tested Charpy specimens. → Stud welding is preferred for a quick installation, almost immediately operational. → Friction welding produces better quality welds, but requires a development effort. - Abstract: Reconstitution techniques are often used to allow material from previously fractured Charpy-V specimens to be reused for additional experiments. This paper presents a comparative experimental study of various reconstitution techniques and evaluates the feasibility of these methods for future use in shielded cells. The following techniques were investigated: arc stud welding, 6.0 kW CO 2 continuous wave laser welding, 4.5 kW YAG continuous wave laser welding and friction welding. Subsize Charpy specimens were reconstituted using a 400 W YAG pulsed wave laser. The best result was obtained with arc stud welding; the resilience of the reconstituted specimens and the load-displacement curves agreed well with the reference specimens, and the temperature elevation caused by the welding process was limited to the vicinity of the weld. Good results were also obtained with friction welding; this process led to the best quality welds. Laser welding seems to have affected the central part of the specimens, thus leading to different resilience values and load-displacement curves.

  7. A Comparative Study of Human Saposins

    Directory of Open Access Journals (Sweden)

    María Garrido-Arandia

    2018-02-01

    Full Text Available Saposins are small proteins implicated in trafficking and loading of lipids onto Cluster of Differentiation 1 (CD1 receptor proteins that in turn present lipid antigens to T cells and a variety of T-cell receptors, thus playing a crucial role in innate and adaptive immune responses in humans. Despite their low sequence identity, the four types of human saposins share a similar folding pattern consisting of four helices linked by three conserved disulfide bridges. However, their lipid-binding abilities as well as their activities in extracting, transporting and loading onto CD1 molecules a variety of sphingo- and phospholipids in biological membranes display two striking characteristics: a strong pH-dependence and a structural change between a compact, closed conformation and an open conformation. In this work, we present a comparative computational study of structural, electrostatic, and dynamic features of human saposins based upon their available experimental structures. By means of structural alignments, surface analyses, calculation of pH-dependent protonation states, Poisson-Boltzmann electrostatic potentials, and molecular dynamics simulations at three pH values representative of biological media where saposins fulfill their function, our results shed light into their intrinsic features. The similarities and differences in this class of proteins depend on tiny variations of local structural details that allow saposins to be key players in triggering responses in the human immune system.

  8. Assays for mammalian tyrosinase: a comparative study

    International Nuclear Information System (INIS)

    Jara, J.R.; Solano, F.; Lozano, J.A.

    1988-01-01

    This work describes a comparative study of the tyrosinase activity determined using three methods which are the most extensively employed; two radiometric assays using L-tyrosine as substrate (tyrosine hydroxylase and melanin formation activities) and one spectrophotometric assay using L-dopa (dopa oxidase activity). The three methods were simultaneously employed to measure the activities of the soluble, melanosomal, and microsomal tyrosinase isozymes from Harding-Passey mouse melanoma through their purification processes. The aim of this study was to find any correlation among the tyrosinase activities measured by the three different assays and to determine whether that correlation varied with the isozyme and its degree of purification. The results show that mammalian tyrosinase has a greater turnover number for L-dopa than for L-tyrosine. Thus, enzyme activity, expressed as mumol of substrate transformed per min, is higher in assays using L-dopa as substrate than those using L-tyrosine. Moreover, the percentage of hydroxylated L-tyrosine that is converted into melanin is low and is affected by several factors, apparently decreasing the tyrosinase activity measured by the melanin formation assay. Bearing these considerations in mind, average interassay factors are proposed. Their values are 10 to transform melanin formation into tyrosine hydroxylase activity, 100 to transform tyrosine hydroxylase into dopa oxidase activity, and 1,000 to transform melanin formation into dopa oxidase activity. Variations in these values due to the presence in the tyrosinase preparations of either inhibitors or regulatory factors in melanogenesis independent of tyrosinase are also discussed

  9. Stereoscopic Visualization of Diffusion Tensor Imaging Data: A Comparative Survey of Visualization Techniques

    International Nuclear Information System (INIS)

    Raslan, O.; Debnam, J.M.; Ketonen, L.; Kumar, A.J.; Schellingerhout, D.; Wang, J.

    2013-01-01

    Diffusion tensor imaging (DTI) data has traditionally been displayed as a gray scale functional anisotropy map (GSFM) or color coded orientation map (CCOM). These methods use black and white or color with intensity values to map the complex multidimensional DTI data to a two-dimensional image. Alternative visualization techniques, such as V m ax maps utilize enhanced graphical representation of the principal eigenvector by means of a headless arrow on regular non stereoscopic (VM) or stereoscopic display (VMS). A survey of clinical utility of patients with intracranial neoplasms was carried out by 8 neuro radiologists using traditional and nontraditional methods of DTI display. Pairwise comparison studies of 5 intracranial neoplasms were performed with a structured questionnaire comparing GSFM, CCOM, VM, and VMS. Six of 8 neuro radiologists favored V m ax maps over traditional methods of display (GSFM and CCOM). When comparing the stereoscopic (VMS) and the non-stereoscopic (VM) modes, 4 favored VMS, 2 favored VM, and 2 had no preference. In conclusion, processing and visualizing DTI data stereoscopically is technically feasible. An initial survey of users indicated that V m ax based display methodology with or without stereoscopic visualization seems to be preferred over traditional methods to display DTI data.

  10. Comparing orbiter and rover image-based mapping of an ancient sedimentary environment, Aeolis Palus, Gale crater, Mars

    Science.gov (United States)

    Stack, Kathryn M.; Edwards, Christopher; Grotzinger, J. P.; Gupta, S.; Sumner, D.; Edgar, Lauren; Fraeman, A.; Jacob, S.; LeDeit, L.; Lewis, K.W.; Rice, M.S.; Rubin, D.; Calef, F.; Edgett, K.; Williams, R.M.E.; Williford, K.H.

    2016-01-01

    This study provides the first systematic comparison of orbital facies maps with detailed ground-based geology observations from the Mars Science Laboratory (MSL) Curiosity rover to examine the validity of geologic interpretations derived from orbital image data. Orbital facies maps were constructed for the Darwin, Cooperstown, and Kimberley waypoints visited by the Curiosity rover using High Resolution Imaging Science Experiment (HiRISE) images. These maps, which represent the most detailed orbital analysis of these areas to date, were compared with rover image-based geologic maps and stratigraphic columns derived from Curiosity’s Mast Camera (Mastcam) and Mars Hand Lens Imager (MAHLI). Results show that bedrock outcrops can generally be distinguished from unconsolidated surficial deposits in high-resolution orbital images and that orbital facies mapping can be used to recognize geologic contacts between well-exposed bedrock units. However, process-based interpretations derived from orbital image mapping are difficult to infer without known regional context or observable paleogeomorphic indicators, and layer-cake models of stratigraphy derived from orbital maps oversimplify depositional relationships as revealed from a rover perspective. This study also shows that fine-scale orbital image-based mapping of current and future Mars landing sites is essential for optimizing the efficiency and science return of rover surface operations.

  11. Image processing of angiograms: A pilot study

    Science.gov (United States)

    Larsen, L. E.; Evans, R. A.; Roehm, J. O., Jr.

    1974-01-01

    The technology transfer application this report describes is the result of a pilot study of image-processing methods applied to the image enhancement, coding, and analysis of arteriograms. Angiography is a subspecialty of radiology that employs the introduction of media with high X-ray absorption into arteries in order to study vessel pathology as well as to infer disease of the organs supplied by the vessel in question.

  12. Study on Processing Method of Image Shadow

    Directory of Open Access Journals (Sweden)

    Wang Bo

    2014-07-01

    Full Text Available In order to effectively remove disturbance of shadow and enhance robustness of information processing of computer visual image, this paper makes study on inspection and removal of image shadow. It makes study the continual removal algorithm of shadow based on integration, the illumination surface and texture, it respectively introduces their work principles and realization method, it can effectively carrying processing for shadow by test.

  13. Comparative methods for PET image segmentation in pharyngolaryngeal squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland); University of Groningen, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands); Abdoli, Mehrsima [University of Groningen, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands); Fuentes, Carolina Llina [Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva (Switzerland); Naqa, Issam M.El [McGill University, Department of Medical Physics, Montreal (Canada)

    2012-05-15

    Several methods have been proposed for the segmentation of {sup 18}F-FDG uptake in PET. In this study, we assessed the performance of four categories of {sup 18}F-FDG PET image segmentation techniques in pharyngolaryngeal squamous cell carcinoma using clinical studies where the surgical specimen served as the benchmark. Nine PET image segmentation techniques were compared including: five thresholding methods; the level set technique (active contour); the stochastic expectation-maximization approach; fuzzy clustering-based segmentation (FCM); and a variant of FCM, the spatial wavelet-based algorithm (FCM-SW) which incorporates spatial information during the segmentation process, thus allowing the handling of uptake in heterogeneous lesions. These algorithms were evaluated using clinical studies in which the segmentation results were compared to the 3-D biological tumour volume (BTV) defined by histology in PET images of seven patients with T3-T4 laryngeal squamous cell carcinoma who underwent a total laryngectomy. The macroscopic tumour specimens were collected ''en bloc'', frozen and cut into 1.7- to 2-mm thick slices, then digitized for use as reference. The clinical results suggested that four of the thresholding methods and expectation-maximization overestimated the average tumour volume, while a contrast-oriented thresholding method, the level set technique and the FCM-SW algorithm underestimated it, with the FCM-SW algorithm providing relatively the highest accuracy in terms of volume determination (-5.9 {+-} 11.9%) and overlap index. The mean overlap index varied between 0.27 and 0.54 for the different image segmentation techniques. The FCM-SW segmentation technique showed the best compromise in terms of 3-D overlap index and statistical analysis results with values of 0.54 (0.26-0.72) for the overlap index. The BTVs delineated using the FCM-SW segmentation technique were seemingly the most accurate and approximated closely the 3-D BTVs

  14. Chronic pelvic pain: how does noninvasive imaging compare with diagnostic laparoscopy?

    Science.gov (United States)

    Tirlapur, Seema A; Daniels, Jane P; Khan, Khalid S

    2015-12-01

    Chronic pelvic pain (CPP) has an annual prevalence of 38/1000 in the UK, with coexisting pathologies often present. Diagnostic laparoscopy has long been the gold standard diagnostic test, but with up to 40% showing no abnormality, we explore the value of noninvasive imaging, such as pelvic ultrasound and MRI. A literature review from inception until January 2015 of the following databases: PubMed, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica database, and System for Information on Grey Literature in Europe were performed to identify published studies assessing the usefulness of ultrasound, MRI, and laparoscopy in the diagnosis of CPP. Three studies (194 women) addressed their comparative performance in patients with endometriosis, showing the sensitivity of ultrasound ranged between 58 and 88.5%; MRI was 56-91.5% and in the one study using histology as its reference standard, the sensitivity of laparoscopy was 85.7%. Noninvasive imaging has the additional benefit of being well tolerated, safer, and cheaper than surgery. CPP, by nature of its multifactorial causation, can be difficult to manage and often requires a multidisciplinary team. Ultrasound and MRI may provide information about the presence or lack of abnormality, which would allow general practitioners or office gynaecologists to initiate treatment and think about surgery as a second-line investigative tool.

  15. Comparative silicone breast implant evaluation using mammography, sonography, and magnetic resonance imaging: experience with 59 implants.

    Science.gov (United States)

    Ahn, C Y; DeBruhl, N D; Gorczyca, D P; Shaw, W W; Bassett, L W

    1994-10-01

    With the current controversy regarding the safety of silicone implants, the detection and evaluation of implant rupture are causing concern for both plastic surgeons and patients. Our study obtained comparative value analysis of mammography, sonography, and magnetic resonance imaging (MRI) in the detection of silicone implant rupture. Twenty-nine symptomatic patients (total of 59 silicone implants) were entered into the study. Intraoperative findings revealed 21 ruptured implants (36 percent). During physical examination, a positive "squeeze test" was highly suggestive of implant rupture. Mammograms were obtained of 51 implants (sensitivity 11 percent, specificity 89 percent). Sonography was performed on 57 implants (sensitivity 70 percent, specificity 92 percent). MRI was performed on 55 implants (sensitivity 81 percent, specificity 92 percent). Sonographically, implant rupture is demonstrated by the "stepladder sign." Double-lumen implants may appear as false-positive results for rupture on sonography. On MRI, the "linguine sign" represents disrupted fragments of a ruptured implant. The most reliable imaging modality for implant rupture detection is MRI, followed by sonogram. Mammogram is the least reliable. Our study supports the clinical indication and diagnostic value of sonogram and MRI in the evaluation of symptomatic breast implant patients.

  16. Fundus autofluorescence and colour fundus imaging compared during telemedicine screening in patients with diabetes.

    Science.gov (United States)

    Kolomeyer, Anton M; Baumrind, Benjamin R; Szirth, Bernard C; Shahid, Khadija; Khouri, Albert S

    2013-06-01

    We investigated the use of fundus autofluorescence (FAF) imaging in screening the eyes of patients with diabetes. Images were obtained from 50 patients with type 2 diabetes undergoing telemedicine screening with colour fundus imaging. The colour and FAF images were obtained with a 15.1 megapixel non-mydriatic retinal camera. Colour and FAF images were compared for pathology seen in nonproliferative and proliferative diabetic retinopathy (NPDR and PDR, respectively). A qualitative assessment was made of the ease of detecting early retinopathy changes and the extent of existing retinopathy. The mean age of the patients was 47 years, most were male (82%) and most were African American (68%). Their mean visual acuity was 20/45 and their mean intraocular pressure was 14.3 mm Hg. Thirty-eight eyes (76%) did not show any diabetic retinopathy changes on colour or FAF imaging. Seven patients (14%) met the criteria for NPDR and five (10%) for severe NPDR or PDR. The most common findings were microaneurysms, hard exudates and intra-retinal haemorrhages (IRH) (n = 6 for each). IRH, microaneurysms and chorioretinal scars were more easily visible on FAF images. Hard exudates, pre-retinal haemorrhage and fibrosis, macular oedema and Hollenhorst plaque were easier to identify on colour photographs. The value of FAF imaging as a complementary technique to colour fundus imaging in detecting diabetic retinopathy during ocular screening warrants further investigation.

  17. Comparative assessments of the effects of alcohol exposure on fetal brain development using optical coherence tomography and ultrasound imaging

    Science.gov (United States)

    Sudheendran, Narendran; Bake, Shameena; Miranda, Rajesh C.; Larin, Kirill V.

    2013-02-01

    The developing fetal brain is vulnerable to a variety of environmental agents including maternal ethanol consumption. Preclinical studies on the development and amelioration of fetal teratology would be significantly facilitated by the application of high resolution imaging technologies like optical coherence tomography (OCT) and high-frequency ultrasound (US). This study investigates the ability of these imaging technologies to measure the effects of maternal ethanol exposure on brain development, ex vivo, in fetal mice. Pregnant mice at gestational day 12.5 were administered ethanol (3 g/Kg b.wt.) or water by intragastric gavage, twice daily for three consecutive days. On gestational day 14.5, fetuses were collected and imaged. Three-dimensional images of the mice fetus brains were obtained by OCT and high-resolution US, and the volumes of the left and right ventricles of the brain were measured. Ethanol-exposed fetuses exhibited a statistically significant, 2-fold increase in average left and right ventricular volumes compared with the ventricular volume of control fetuses, with OCT-derived measures of 0.38 and 0.18 mm3, respectively, whereas the boundaries of the fetal mouse lateral ventricles were not clearly definable with US imaging. Our results indicate that OCT is a useful technology for assessing ventriculomegaly accompanying alcohol-induced developmental delay. This study clearly demonstrated advantages of using OCT for quantitative assessment of embryonic development compared with US imaging.

  18. FAIR imaging of the liver. A preliminary study

    International Nuclear Information System (INIS)

    Kiryu, Shigeru; Machida, Toru; Noda, Masanobu

    1998-01-01

    Flow-sensitive alternating inversion recovery (FAIR) technique has recently been introduced for perfusion or functional MR studies of the brain. In the imaging of liver neoplasms, the evaluation of tumor vascularity is important for diagnosis, and therefore the FAIR technique may potentially complement liver MR imaging. The purpose of this study was to evaluate the usefulness of a FAIR sequence in MR imaging of the liver and to compare it with arterial-phase images of dynamic MR imaging. One volunteer and six patients with focal hepatic lesions (one with hepatocellular carcinoma (HCC), three with metastasis, and two with cavernous hemangioma) underwent FAIR. Short TI (600 ms) and long TI (1200 ms) images were obtained during breath-hold. In normal volunteers, the vessels generated remarkably bright signal in both short and long TI. Signal intensity of liver parenchyma was low in short TI, and became stronger in long TI. Two HCC (in one patient) (100%), one hemangioma (50%), and three metastases (100%) were well delineated as bright lesions. One HCC produced peripheral high intensity in short-TI FAIR image, and this finding was consistent with the result of dynamic MR study. Another HCC, which showed no clear enhancement in the arterial-phase dynamic MRI, was visualized only in long-TI FAIR. One hemangioma, which was clearly seen in FAIR image, showed rapid and strong enhancement on dynamic MRI. It is concluded that FAIR is a promising technique for evaluation of vascularity of hepatic tumors without using contrast materials. (author)

  19. Study of CT image texture using deep learning techniques

    Science.gov (United States)

    Dutta, Sandeep; Fan, Jiahua; Chevalier, David

    2018-03-01

    For CT imaging, reduction of radiation dose while improving or maintaining image quality (IQ) is currently a very active research and development topic. Iterative Reconstruction (IR) approaches have been suggested to be able to offer better IQ to dose ratio compared to the conventional Filtered Back Projection (FBP) reconstruction. However, it has been widely reported that often CT image texture from IR is different compared to that from FBP. Researchers have proposed different figure of metrics to quantitate the texture from different reconstruction methods. But there is still a lack of practical and robust method in the field for texture description. This work applied deep learning method for CT image texture study. Multiple dose scans of a 20cm diameter cylindrical water phantom was performed on Revolution CT scanner (GE Healthcare, Waukesha) and the images were reconstructed with FBP and four different IR reconstruction settings. The training images generated were randomly allotted (80:20) to a training and validation set. An independent test set of 256-512 images/class were collected with the same scan and reconstruction settings. Multiple deep learning (DL) networks with Convolution, RELU activation, max-pooling, fully-connected, global average pooling and softmax activation layers were investigated. Impact of different image patch size for training was investigated. Original pixel data as well as normalized image data were evaluated. DL models were reliably able to classify CT image texture with accuracy up to 99%. Results show that the deep learning techniques suggest that CT IR techniques may help lower the radiation dose compared to FBP.

  20. Comparing the brand image of two market leading pram brands - Bugaboo and Emmaljunga

    OpenAIRE

    Huttula, Tia; Nurminen, Peppi-Sisko

    2017-01-01

    Brand image is one of the most significant factors affecting the success of brands. Information channels have a large impact on brand images, but there is many other aspects on branding. Bugaboo and Emmaljunga are pram brands with different brand image. Emmaljunga is and old and traditional brand, whereas Bugaboo is a new and trendy brand. The case company Lastentarvike is selling Emmaljunga and helps with this research. The main objectives of the thesis project are to study how pra...

  1. A Study of Identification Performance of Facial Regions from CCTV Images

    NARCIS (Netherlands)

    Ali, Tauseef; Tome, Pedro; Fierrez, Julian; Vera-Rodriguez, Ruben; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.; Garain, Utpal; Shafait, Faisal

    This paper focuses on automatic face identification for forensic applications. Forensic examiners compare different parts of the face image obtained from a closed-circuit television (CCTV) image with a database of mug shots or good quality image(s) taken from the suspect. In this work we study and

  2. A study of identification performance of facial regions from CCTV images

    NARCIS (Netherlands)

    Ali, Tauseef; Tom, P.; Fierrez, J.; Vera-Rodriguez, R.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2012-01-01

    This paper focuses on automatic face identification for forensic applications. Forensic examiners compare different parts of the face image obtained from a closed-circuit television (CCTV) image with a database of mug shots or good quality image(s) taken from the suspect. In this work we study and

  3. Comparative performance evaluation of transform coding in image pre-processing

    Science.gov (United States)

    Menon, Vignesh V.; NB, Harikrishnan; Narayanan, Gayathri; CK, Niveditha

    2017-07-01

    We are in the midst of a communication transmute which drives the development as largely as dissemination of pioneering communication systems with ever-increasing fidelity and resolution. Distinguishable researches have been appreciative in image processing techniques crazed by a growing thirst for faster and easier encoding, storage and transmission of visual information. In this paper, the researchers intend to throw light on many techniques which could be worn at the transmitter-end in order to ease the transmission and reconstruction of the images. The researchers investigate the performance of different image transform coding schemes used in pre-processing, their comparison, and effectiveness, the necessary and sufficient conditions, properties and complexity in implementation. Whimsical by prior advancements in image processing techniques, the researchers compare various contemporary image pre-processing frameworks- Compressed Sensing, Singular Value Decomposition, Integer Wavelet Transform on performance. The paper exposes the potential of Integer Wavelet transform to be an efficient pre-processing scheme.

  4. Display of nuclear medicine imaging studies

    International Nuclear Information System (INIS)

    Singh, B.; Kataria, S.K.; Samuel, A.M.

    2002-08-01

    Nuclear medicine imaging studies involve evaluation of a large amount of image data. Digital signal processing techniques have introduced processing algorithms that increase the information content of the display. Nuclear medicine imaging studies require interactive selection of suitable form of display and pre-display processing. Static imaging study requires pre-display processing to detect focal defects. Point operations (histogram modification) along with zoom and capability to display more than one image in one screen is essential. This album mode of display is also applicable to dynamic, MUGA and SPECT data. Isometric display or 3-D graph of the image data is helpful in some cases e.g. point spread function, flood field data. Cine display is used on a sequence of images e.g. dynamic, MUGA and SPECT imaging studies -to assess the spatial movement of tracer with time. Following methods are used at the investigator's discretion for inspection of the 3-D object. 1) Display of orthogonal projections, 2) Display of album of user selected coronal/ sagital/ transverse orthogonal slices, 3) Display of three orthogonal slices through user selected point, 4) Display of a set of orthogonal slices generated in the user-selected volume, 5) Generation and display of 3-D shaded surface. 6) Generation of volume data and display along with the 3-D shaded surface, 7) Side by side display orthogonal slices of two 3-D objects. Displaying a set of two-dimensional slices of a 3-D reconstructed object through shows all the defects but lacks the 3-D perspective. Display of shaded surface lacks the ability to show the embedded defects. Volume display -combining the 3-D surface and gray level volume data is perhaps the best form of display. This report describes these forms of display along with the theory. (author)

  5. Comparative electron microscopy and image analysis of oxy- and deoxy-hemocyanin from the spiny lobster Panulirus interruptus

    NARCIS (Netherlands)

    Haas, Felix de; Breemen, Jan F.L. van; Boekema, Egbert J.; Keegstra, Wilko; Bruggen, Ernst F.J. van

    1993-01-01

    Structural differences between oxy-hemocyanin and deoxy-hemocyanin from the spiny lobster P. interruptus were studied by electron microscopy and image analysis of negatively stained preparations. Projections of the hexameric P. interruptus hemocyanin from electron microscopy were compared with

  6. Comparative Analysis between LDR and HDR Images for Automatic Fruit Recognition and Counting

    Directory of Open Access Journals (Sweden)

    Tatiana M. Pinho

    2017-01-01

    Full Text Available Precision agriculture is gaining an increasing interest in the current farming paradigm. This new production concept relies on the use of information technology (IT to provide a control and supervising structure that can lead to better management policies. In this framework, imaging techniques that provide visual information over the farming area play an important role in production status monitoring. As such, accurate representation of the gathered production images is a major concern, especially if those images are used in detection and classification tasks. Real scenes, observed in natural environment, present high dynamic ranges that cannot be represented by the common LDR (Low Dynamic Range devices. However, this issue can be handled by High Dynamic Range (HDR images since they have the ability to store luminance information similarly to the human visual system. In order to prove their advantage in image processing, a comparative analysis between LDR and HDR images, for fruits detection and counting, was carried out. The obtained results show that the use of HDR images improves the detection performance to more than 30% when compared to LDR.

  7. Comparative Studies on Some Physicochemical Properties of ...

    African Journals Online (AJOL)

    Industrial and nutritional processes have increased the demands for oil and this in turn has led to the search for oils from different types of seeds. It is in this vein that baobab seed oil was extracted, analyzed and some of it physicochemical properties compared with those of vegetable, peanut and palm oils. The percentage ...

  8. A comparative study of fingerprint thinning algorithms

    CSIR Research Space (South Africa)

    Khanyile, NP

    2011-08-01

    Full Text Available are compared in terms of the quality of the skeletons they produce (i.e. connectivity and spurious branches) as well as the time complexity associated with each algorithm. Results show that faster algorithms have difficulty preserving connectivity. Zhang...

  9. Counseling in Costa Rica: A Comparative Study

    Science.gov (United States)

    Collier, Crystal

    2013-01-01

    With one of the world's most comprehensive universal healthcare systems, medical tourism in Costa Rica has increased significantly over the past few decades. American tourists save up to 80% of comparative costs for procedures, from heart surgery to root canal treatment. Although many Costa Rican healthcare professionals receive training in North…

  10. Calcaneal fracture classification: a comparative study

    NARCIS (Netherlands)

    Schepers, Tim; van Lieshout, Esther M. M.; Ginai, Abida Z.; Mulder, Paul G. H.; Heetveld, Martin J.; Patka, Peter

    2009-01-01

    Comparing different types of calcaneal fractures, associated treatment options, and outcome data is currently hampered by the lack of consensus regarding fracture classification. A systematic search for articles dealing with calcaneal fracture was performed, and the prevalence of use of each

  11. The Teaching of Anthropology: A Comparative Study.

    Science.gov (United States)

    Lombard, Jacques

    1984-01-01

    College-level anthropology teaching in various countries, including Belgium, France, Germany, the Netherlands, Portugal, South Africa, the United Kingdom, and Yugoslavia, is compared. Terminology is examined and historical background is provided. Also discussed are educational crises, the organization of teaching, and teaching methods. (RM)

  12. Abdominal MRI at 3.0 T: LAVA-Flex compared with conventional fat suppression T1-weighted images.

    Science.gov (United States)

    Li, Xing Hui; Zhu, Jiang; Zhang, Xiao Ming; Ji, Yi Fan; Chen, Tian Wu; Huang, Xiao Hua; Yang, Lin; Zeng, Nan Lin

    2014-07-01

    To study liver imaging with volume acceleration-flexible (LAVA-Flex) for abdominal magnetic resonance imaging (MRI) at 3.0 T and compare the image quality of abdominal organs between LAVA-Flex and fast spoiled gradient-recalled (FSPGR) T1-weighted imaging. Our Institutional Review Board approval was obtained in this retrospective study. Sixty-nine subjects had both FSPGR and LAVA-Flex sequences. Two radiologists independently scored the acquisitions for image quality, fat suppression quality, and artifacts and the values obtained were compared with the Wilcoxon signed rank test. According to the signal intensity (SI) measurements, the uniformity of fat suppression, the contrast between muscle and fat and normal liver and liver lesions were compared by the paired t-test. The liver and spleen SI on the fat-only phase were analyzed in the fatty liver patients. Compared with FSPGR imaging, LAVA-Flex images had better and more homogenous fat suppression and lower susceptibility artifact (qualitative scores: 4.70 vs. 4.00, 4.86% vs. 7.14%, 4.60 and 4.10, respectively). The contrast between muscle and fat and between the liver and pathologic lesions was significantly improved on the LAVA-Flex sequence. The contrast value of the fatty liver and spleen was higher than that of the liver and spleen. The LAVA-Flex sequence offers superior and more homogenous fat suppression of the abdomen than does the FSPGR sequence. The fat-only phase can be a simple and effective method of assessing fatty liver. © 2013 Wiley Periodicals, Inc.

  13. HVS scheme for DICOM image compression: Design and comparative performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakar, B. [Biomedical and Engineering Division, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu (India)]. E-mail: prabhakarb@iitm.ac.in; Reddy, M. Ramasubba [Biomedical and Engineering Division, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu (India)

    2007-07-15

    Advanced digital imaging technology in medical domain demands efficient and effective DICOM image compression for progressive image transmission and picture archival. Here a compression system, which incorporates sensitivities of HVS coded with SPIHT quantization, is discussed. The weighting factors derived from luminance CSF are used to transform the wavelet subband coefficients to reflect characteristics of HVS in best possible manner. Mannos et al. and Daly HVS models have been used and results are compared. To evaluate the performance, Eskicioglu chart metric is considered. Experiment is done on both Monochrome and Color Dicom images of MRI, CT, OT, and CR, natural and benchmark images. Reconstructed image through our technique showed improvement in visual quality and Eskicioglu chart metric at same compression ratios. Also the Daly HVS model based compression shows better performance perceptually and quantitatively when compared to Mannos et el. model. Further 'bior4.4' wavelet filter provides better results than 'db9' filter for this compression system. Results give strong evidence that under common boundary conditions; our technique achieves competitive visual quality, compression ratio and coding/decoding time, when compared with jpeg2000 (kakadu)

  14. Magnetic resonance imaging compared with trimodal evoked potentials in possible multiple sclerosis

    International Nuclear Information System (INIS)

    Roullet, E.; Leger-Ravet, M.B.; Amarenco, P.; Marteau, R.; Lavallard-Rousseau, M.-C.; Dupuch, K.; Iba-Zizen, M.T.; Tamraz, J.; Cabanis, E.A.

    1988-01-01

    Magnetic Resonance Imaging (MRI) of the brain and Evoked Potentials (EP) can both demonstrate the presence of clinically unsuspected demyelinating lesions and have proven to be sensitive (but not specific) in the diagnosis of multiple sclerosis (MS). MRI and EP are positive in 90 to 100% of patients with a definite diagnosis of MS. However, few studies have been conducted in patients with a lesser diagnostic certainty. In possible or suspected MS they gave conflicting results, possibly because of technical discrepancies and different clinical inclusion criteria. Since a number of putative new treatments can be evaluated in patients who have a definite diagnosis of MS, but nevertheless a short duration of disease and a low disability, it was decided to compare the sensitivity of MRI and EP as diagnostic tools in possible MS patients. MRI is shown to be more sensitive, shows more multiple lesions and gives a clearer appreciation of their size and exact location than EP. 10 refs.; 3 tabs

  15. Comparing Four Touch-Based Interaction Techniques for an Image-Based Audience Response System

    NARCIS (Netherlands)

    Jorritsma, Wiard; Prins, Jonatan T.; van Ooijen, Peter M. A.

    2015-01-01

    This study aimed to determine the most appropriate touch-based interaction technique for I2Vote, an image-based audience response system for radiology education in which users need to accurately mark a target on a medical image. Four plausible techniques were identified: land-on, take-off,

  16. Hans Strahl's pioneering studies in comparative placentation

    DEFF Research Database (Denmark)

    Carter, Anthony Michael; Mess, A

    2010-01-01

    Hans Strahl, a contemporary of Duval and Hubrecht, made many important contributions to comparative placentation. Despite this he is not well known and some of his original observations tend to be attributed to later authors. Strahl published a classification of placental types based on their shape...... of the most important findings made by Strahl including work on placentation in carnivores and higher primates that remains unsurpassed....

  17. Comparative study of some new EPR dosimeters

    International Nuclear Information System (INIS)

    Alzimami, K.S.; Maghraby, Ahmed M.; Bradley, D.A.

    2014-01-01

    Investigations have been made of four new radiation dosimetry EPR candidates from the same family of materials: sulfamic acid, sulfanillic acid, homotaurine, and taurine. Mass energy attenuation coefficients, mass stopping power values and the time dependence of the radiation induced radicals are compared. Also investigated are the microwave saturation behavior and the effect of applied modulation amplitude on both peak-to-peak line width (W PP ) and peak-to-peak signal height (H PP ). The dosimeters are characterized by simple spectra and stable radiation-induced radicals over reasonable durations, especially in taurine dosimeters. Sulfamic acid dosimeters possessed the highest sensitivity followed by taurine and homotaurine and sulfanillic. - Highlights: ► Several EPR dosimeters were suggested based on SO 3 − radical. ► Taurine, homotaurine, sulfanilic, and sulfamic acid all possess simple EPR spectra. ► Dosimeters were compared to each other in terms of the dosimetric point of view. ► Energy dependence curves of the selected dosimeters were compared to eachother

  18. Magnetic Resonance Imaging of Japanese monkey brains compared with X-ray photography and histology

    International Nuclear Information System (INIS)

    Kaji, Shinji; Matsuda, Keiji; Kawano, Kenji; Komatsu, Hidehiko; Yamane, Shigeru; Yoshizawa, Takashi; Nose, Tadao.

    1991-01-01

    The localization of a small target area in the brain is usually estimated by using stereotaxic atlases, assisted by X-ray photography or electrophysiological mapping, and determined finally by histological reconstruction. Magnetic Resonance Imaging (MRI) can visualize, noninvasively cross sections in any plane of three dimensional structures of the brain. We compared images of MRI, X-ray, and histology from a monkey brain. A Japanese monkey (Macaca fuscata, male, 11 kg) was anesthetised, fixed in a newly developed magnetic-free stereotaxic apparatus, and mounted in the MRI scanner unit (BRUKER, BIOSPEC 24/40, 2.4 Tesla). Some para-saggital (5 mm thick) and para-frontal (2.5 mm thick, every 5 mm distance) images were obtained. The outline of the bone on the MRI image was compared with that on the X-ray photograph taken by an X-ray instrument (Toshiba, TR-80A). The two images fitted very well. The animal was sacrificed, the brain was sliced in 100 μm and stained with Cresyl violet. The histological preparations were shrunk some 10 % during the process, which was revealed by comparison of MRI, X-ray, and histological images. In conclusion, MRI images are reliable enough to determine a small target in deep structures of the brain, and their superimposed images on X-rays will assist in identifying the location of electrode or needle tips. We constructed a data base of these MRI and histological images on a Macintosh computer, and they can be easily accessed by a mouse operation. (author)

  19. Feasibility study of CT perfusion imaging for prostate carcinoma

    International Nuclear Information System (INIS)

    Cullu, Nesat; Kantarci, Mecit; Ogul, Hayri; Pirimoglu, Berhan; Karaca, Leyla; Kizrak, Yesim; Adanur, Senol; Koc, Erdem; Polat, Ozkan; Okur, Aylin

    2014-01-01

    The aim of this feasibility study was to obtain initial data with which to assess the efficiency of perfusion CT imaging (CTpI) and to compare this with magnetic resonance imaging (MRI) in the diagnosis of prostate carcinoma. This prospective study involved 25 patients with prostate carcinoma undergoing MRI and CTpI. All analyses were performed on T2-weighted images (T2WI), apparent diffusion coefficient (ADC) maps, diffusion-weighted images (DWI) and CTp images. We compared the performance of T2WI combined with DWI and CTp alone. The study was approved by the local ethics committee, and written informed consent was obtained from all patients. Tumours were present in 87 areas according to the histopathological results. The diagnostic performance of the T2WI+DWI+CTpI combination was significantly better than that of T2WI alone for prostate carcinoma (P < 0.001). The diagnostic value of CTpI was similar to that of T2WI+DWI in combination. There were statistically significant differences in the blood flow and permeability surface values between prostate carcinoma and background prostate on CTp images. CTp may be a valuable tool for detecting prostate carcinoma and may be preferred in cases where MRI is contraindicated. If this technique is combined with T2WI and DWI, its diagnostic value is enhanced. (orig.)

  20. The image evaluation of iterative motion correction reconstruction algorithm PROPELLER T2-weighted imaging compared with MultiVane T2-weighted imaging

    Science.gov (United States)

    Lee, Suk-Jun; Yu, Seung-Man

    2017-08-01

    The purpose of this study was to evaluate the usefulness and clinical applications of MultiVaneXD which was applying iterative motion correction reconstruction algorithm T2-weighted images compared with MultiVane images taken with a 3T MRI. A total of 20 patients with suspected pathologies of the liver and pancreatic-biliary system based on clinical and laboratory findings underwent upper abdominal MRI, acquired using the MultiVane and MultiVaneXD techniques. Two reviewers analyzed the MultiVane and MultiVaneXD T2-weighted images qualitatively and quantitatively. Each reviewer evaluated vessel conspicuity by observing motion artifacts and the sharpness of the portal vein, hepatic vein, and upper organs. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated by one reviewer for quantitative analysis. The interclass correlation coefficient was evaluated to measure inter-observer reliability. There were significant differences between MultiVane and MultiVaneXD in motion artifact evaluation. Furthermore, MultiVane was given a better score than MultiVaneXD in abdominal organ sharpness and vessel conspicuity, but the difference was insignificant. The reliability coefficient values were over 0.8 in every evaluation. MultiVaneXD (2.12) showed a higher value than did MultiVane (1.98), but the difference was insignificant ( p = 0.135). MultiVaneXD is a motion correction method that is more advanced than MultiVane, and it produced an increased SNR, resulting in a greater ability to detect focal abdominal lesions.

  1. Comparative transport studies of ''1212'' superconductors

    International Nuclear Information System (INIS)

    Gapud, Albert; Wu, Judy; Yan, Shaolin; Xie, Yi-Yuan; Kang, Byeongwon; Siegal, Michael P.; Overmyer, Donald L.

    2000-01-01

    HgBa 2 CaCu 2 O 6+δ (Hg-1212) thin films were fabricated by exchanging the TI cations in TlBa 2 CaCu 2 O 7-δ (Tl-1212) thin films with Hg cations, causing a 30-K increase in Tc. To determine how this exchange effects such a Tc increase, the irreversibility lines, temperature dependence of critical current density, and temperature dependence of Hall angle of Hg-1212 and T1-1212 thin films were measured and then compared. The results strongly suggest that the Tc shift is caused by a doubling of charge carrier density

  2. Three-dimensional velocity map imaging: Setup and resolution improvement compared to three-dimensional ion imaging

    International Nuclear Information System (INIS)

    Kauczok, S.; Goedecke, N.; Veckenstedt, M.; Maul, C.; Gericke, K.-H.; Chichinin, A. I.

    2009-01-01

    For many years the three-dimensional (3D) ion imaging technique has not benefited from the introduction of ion optics into the field of imaging in molecular dynamics. Thus, a lower resolution of kinetic energy as in comparable techniques making use of inhomogeneous electric fields was inevitable. This was basically due to the fact that a homogeneous electric field was needed in order to obtain the velocity component in the direction of the time of flight spectrometer axis. In our approach we superimpose an Einzel lens field with the homogeneous field. We use a simulation based technique to account for the distortion of the ion cloud caused by the inhomogeneous field. In order to demonstrate the gain in kinetic energy resolution compared to conventional 3D Ion Imaging, we use the spatial distribution of H + ions emerging from the photodissociation of HCl following the two photon excitation to the V 1 Σ + state. So far a figure of merit of approximately four has been achieved, which means in absolute numbers Δv/v=0.022 compared to 0.086 at v≅17 000 m/s. However, this is not a theoretical limit of the technique, but due to our rather short TOF spectrometer (15 cm). The photodissociation of HBr near 243 nm has been used to recognize and eliminate systematic deviations between the simulation and the experimentally observed distribution. The technique has also proven to be essential for the precise measurement of translationally cold distributions.

  3. Advertisement Analysis: A Comparative Critical Study

    Science.gov (United States)

    Abdelaal, Noureldin Mohamed; Sase, Amal Saleh

    2014-01-01

    This study aimed at analyzing two advertisements, and investigating how advertisers use discourse and semiotics to make people and customers buy into their ideas, beliefs, or simply their products. The two advertisements analyzed are beauty products which have been selected from internet magazines. The methodology adopted in this study is…

  4. Comparative studies on different molecular methods for ...

    African Journals Online (AJOL)

    The present study aims to evaluate two molecular methods for epidemiological typing of multi drug resistant Klebsiella pneumoniae isolated from Mansoura Hospitals. In this study, a total of 300 clinical isolates were collected from different patients distributed among Mansoura Hospitals, Dakahlia governorate, Egypt.

  5. A Comparative Comment on the Case Studies

    DEFF Research Database (Denmark)

    Kjeldsen, Christian Christrup; Ley, Thomas; Jensen, Niels Rosendal

    2012-01-01

    Denne konklusion sammenfatter hovedtrækkene af de gennemførte case studies i WorkAble-projektet. Vigtige pointer er, at unge på tværs af de forskellige case studies har vanskeligt ved at blive hørt og taget alvorligt. I stedet spises de af med "realistisk vejledning" eller dårlige uddannelses- og...

  6. Comparative study of environmental impact assessment methods ...

    African Journals Online (AJOL)

    This study aims to introduce and systematically investigate the environmental issues during important decision-making stages. Meanwhile, impacts of development on the environmental components will be also analyzed. This research studies various methods of predicting the environmental changes and determining the ...

  7. Comparative diagnostic study of staging in renal cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Masaharu; Mori, Masaki; Ito, Sachiko and others

    1986-04-01

    A comparative diagnostic study was carried out on 56 patients with pathologically proven renal cell carcinoma which had been staged by CT, US, angiography (AG) and lymphography (LG) between June, 1980, and May, 1985. The confirmation of the tumor extent was established by surgery and microscopic examination in all patients except three, in whom the extent of the tumor was determined at autopsy. CT and AG were performed in all cases. It was also studied how far various factors such as histologic architecture, cell type, grade, growth mode, tumor necrosis and bleeding were related with prognosis, and how to evaluate them in imaging modality. Concerning the T factor, there was no difference in diagnostic ability between images, and since prognosis of T4 was inferior to those of T2 and T3, diagnosis of T4 was seen to require particular attention. Drawing ability of N and V factors was poor in US. In LG, evaluation of regional lymph nodes was difficult, so this seems to be an unnecessary examination because CT can provide sufficient evaluation. By imaging modality, diagnosis of architecture and cell type was difficult. By AG, avascular to hypovascular tumors were of solid type, and there were many spindle or pleomorphic cell types and combination of tubular-granular types, while the papillary type was few. By macroscopic growth mode, the infiltrating type was poor in prognosis, and the presence or absence of halo was evaluated by CT and AG. Prognosis was favorable in cases having no necrosis in the tumor or accompanied by hemorrhage. For the purpose of diagnosis, CT was found to be sufficient, and it was concluded that AG may be used only for the purpose of renal arterial embolization as a preoperative treatment of low-stage cases subjected to nephrectomy. US is sufficient only if satisfying the role of screening. (J.P.N.).

  8. Towards a five-minute comprehensive cardiac MR examination using highly accelerated parallel imaging with a 32-element coil array: feasibility and initial comparative evaluation.

    Science.gov (United States)

    Xu, Jian; Kim, Daniel; Otazo, Ricardo; Srichai, Monvadi B; Lim, Ruth P; Axel, Leon; Mcgorty, Kelly Anne; Niendorf, Thoralf; Sodickson, Daniel K

    2013-07-01

    To evaluate the feasibility and perform initial comparative evaluations of a 5-minute comprehensive whole-heart magnetic resonance imaging (MRI) protocol with four image acquisition types: perfusion (PERF), function (CINE), coronary artery imaging (CAI), and late gadolinium enhancement (LGE). This study protocol was Health Insurance Portability and Accountability Act (HIPAA)-compliant and Institutional Review Board-approved. A 5-minute comprehensive whole-heart MRI examination protocol (Accelerated) using 6-8-fold-accelerated volumetric parallel imaging was incorporated into and compared with a standard 2D clinical routine protocol (Standard). Following informed consent, 20 patients were imaged with both protocols. Datasets were reviewed for image quality using a 5-point Likert scale (0 = non-diagnostic, 4 = excellent) in blinded fashion by two readers. Good image quality with full whole-heart coverage was achieved using the accelerated protocol, particularly for CAI, although significant degradations in quality, as compared with traditional lengthy examinations, were observed for the other image types. Mean total scan time was significantly lower for the Accelerated as compared to Standard protocols (28.99 ± 4.59 min vs. 1.82 ± 0.05 min, P simplified scan prescription and high spatial and temporal resolution enabled by highly parallel imaging technology. The study also highlights technical hurdles that remain to be addressed. Although image quality remained diagnostic for most scan types, the reduced image quality of PERF, CINE, and LGE scans in the Accelerated protocol remain a concern. Copyright © 2012 Wiley Periodicals, Inc.

  9. Evaluation of computed tomography post-processing images in postoperative assessment of Lisfranc injuries compared with plain radiographs.

    Science.gov (United States)

    Li, Haobo; Chen, Yanxi; Qiang, Minfei; Zhang, Kun; Jiang, Yuchen; Zhang, Yijie; Jia, Xiaoyang

    2017-06-14

    The objective of this study is to evaluate the value of computed tomography (CT) post-processing images in postoperative assessment of Lisfranc injuries compared with plain radiographs. A total of 79 cases with closed Lisfranc injuries that were treated with conventional open reduction and internal fixation from January 2010 to June 2016 were analyzed. Postoperative assessment was performed by two independent orthopedic surgeons with both plain radiographs and CT post-processing images. Inter- and intra-observer agreement were analyzed by kappa statistics while the differences between the two postoperative imaging assessments were assessed using the χ 2 test (McNemar's test). Significance was assumed when p processing images was much higher than that of plain radiographs. Non-anatomic reduction was more easily identified in patients with injuries of Myerson classifications A, B1, B2, and C1 using CT post-processing images with overall groups (p processing images with overall groups (p processing images can be more reliable than plain radiographs in the postoperative assessment of reduction and implant placement for Lisfranc injuries.

  10. Nonlinear analysis of RED - a comparative study

    International Nuclear Information System (INIS)

    Jiang Kai; Wang Xiaofan; Xi Yugeng

    2004-01-01

    Random Early Detection (RED) is an active queue management (AQM) mechanism for routers on the Internet. In this paper, performance of RED and Adaptive RED are compared from the viewpoint of nonlinear dynamics. In particular, we reveal the relationship between the performance of the network and its nonlinear dynamical behavior. We measure the maximal Lyapunov exponent and Hurst parameter of the average queue length of RED and Adaptive RED, as well as the throughput and packet loss rate of the aggregate traffic on the bottleneck link. Our simulation scenarios include FTP flows and Web flows, one-way and two-way traffic. In most situations, Adaptive RED has smaller maximal Lyapunov exponents, lower Hurst parameters, higher throughput and lower packet loss rate than that of RED. This confirms that Adaptive RED has better performance than RED

  11. Comparative study of void fraction models

    International Nuclear Information System (INIS)

    Borges, R.C.; Freitas, R.L.

    1985-01-01

    Some models for the calculation of void fraction in water in sub-cooled boiling and saturated vertical upward flow with forced convection have been selected and compared with experimental results in the pressure range of 1 to 150 bar. In order to know the void fraction axial distribution it is necessary to determine the net generation of vapour and the fluid temperature distribution in the slightly sub-cooled boiling region. It was verified that the net generation of vapour was well represented by the Saha-Zuber model. The selected models for the void fraction calculation present adequate results but with a tendency to super-estimate the experimental results, in particular the homogeneous models. The drift flux model is recommended, followed by the Armand and Smith models. (F.E.) [pt

  12. Nonlinear analysis of RED - a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Kai; Wang Xiaofan E-mail: xfwang@sjtu.edu.cn; Xi Yugeng

    2004-09-01

    Random Early Detection (RED) is an active queue management (AQM) mechanism for routers on the Internet. In this paper, performance of RED and Adaptive RED are compared from the viewpoint of nonlinear dynamics. In particular, we reveal the relationship between the performance of the network and its nonlinear dynamical behavior. We measure the maximal Lyapunov exponent and Hurst parameter of the average queue length of RED and Adaptive RED, as well as the throughput and packet loss rate of the aggregate traffic on the bottleneck link. Our simulation scenarios include FTP flows and Web flows, one-way and two-way traffic. In most situations, Adaptive RED has smaller maximal Lyapunov exponents, lower Hurst parameters, higher throughput and lower packet loss rate than that of RED. This confirms that Adaptive RED has better performance than RED.

  13. Interatrial septum pacing decreases atrial dyssynchrony on strain rate imaging compared with right atrial appendage pacing.

    Science.gov (United States)

    Yasuoka, Yoshinori; Abe, Haruhiko; Umekawa, Seiko; Katsuki, Keiko; Tanaka, Norio; Araki, Ryo; Imanaka, Takahiro; Matsutera, Ryo; Morisawa, Daisuke; Kitada, Hirokazu; Hattori, Susumu; Noda, Yoshiki; Adachi, Hidenori; Sasaki, Tatsuya; Miyatake, Kunio

    2011-03-01

    Interatrial septum pacing (IAS-P) decreases atrial conduction delay compared with right atrial appendage pacing (RAA-P). We evaluate the atrial contraction with strain rate of tissue Doppler imaging (TDI) during sinus activation or with IAS-P or RAA-P. Fifty-two patients with permanent pacemaker for sinus node disease were enrolled in the study. Twenty-three subjects were with IAS-P and 29 with RAA-P. The time from end-diastole to peak end-diastolic strain rate was measured and corrected with RR interval on electrocardiogram. It was defined as the time from end-diastole to peak end-diastolic strain rate (TSRc), and the balance between maximum and minimum TSRc at three sites (ΔTSRc) was compared during sinus activation and with pacing rhythm in each group. There were no significant differences observed in general characteristics and standard echocardiographic parameters except the duration of pacing P wave between the two groups. The duration was significantly shorter in the IAS-P group compared with the RAA-P group (95 ± 34 vs 138 ± 41; P = 0.001). TSRc was significantly different between sinus activation and pacing rhythm (36.3 ± 35.7 vs 61.6 ± 36.3; P = 0.003) in the RAA-P group, whereas no significant differences were observed in the IAS-P group (25.4 ± 12.1 vs 27.7 ± 14.7; NS). During the follow-up (mean 2.4 ± 0.7 years), the incidence of paroxysmal atrial fibrillation (AF) conversion to permanent AF was not significantly different between the two groups. IAS-P decreased the contraction delay on atrial TDI compared to RAA-P; however, it did not contribute to the reduction of AF incidence in the present study. ©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.

  14. War And Reconstruction: Four Comparative Case Studies

    African Journals Online (AJOL)

    The four case studies are taken from four different continents, four different wars under .... and revolutionary changes in the structures and power relations in society and ..... general public accept nowadays that although states' rights were the ...

  15. Phytochemical screening and study of comparative antibacterial ...

    African Journals Online (AJOL)

    SARAH

    2013-06-30

    Jun 30, 2013 ... Objectives: In this study, methanol, ethanol and aqueous extracts of ... of resistance in bacteria previously susceptible to ... increase in antibiotic resistance in hospitals and ..... extraction process (Masoko et al., 2008). Use of ...

  16. COMPARATIVE STUDY OF HONEY COLLECTED FROM ...

    African Journals Online (AJOL)

    lanez

    2014-06-30

    Jun 30, 2014 ... content, electrical conductivity, total dissolved solids, color intensity ... used in this study on the basis of date of harvest, geographical origin. ... The determination of physical and chemical parameters such as content of water, ...

  17. Comparing the Scoring of Human Decomposition from Digital Images to Scoring Using On-site Observations.

    Science.gov (United States)

    Dabbs, Gretchen R; Bytheway, Joan A; Connor, Melissa

    2017-09-01

    When in forensic casework or empirical research in-person assessment of human decomposition is not possible, the sensible substitution is color photographic images. To date, no research has confirmed the utility of color photographic images as a proxy for in situ observation of the level of decomposition. Sixteen observers scored photographs of 13 human cadavers in varying decomposition stages (PMI 2-186 days) using the Total Body Score system (total n = 929 observations). The on-site TBS was compared with recorded observations from digital color images using a paired samples t-test. The average difference between on-site and photographic observations was -0.20 (t = -1.679, df = 928, p = 0.094). Individually, only two observers, both students with human decomposition based on digital images can be substituted for assessments based on observation of the corpse in situ, when necessary. © 2017 American Academy of Forensic Sciences.

  18. Functional brain response to food images in successful adolescent weight losers compared with normal-weight and overweight controls.

    Science.gov (United States)

    Jensen, Chad D; Kirwan, C Brock

    2015-03-01

    Research conducted with adults suggests that successful weight losers demonstrate greater activation in brain regions associated with executive control in response to viewing high-energy foods. No previous studies have examined these associations in adolescents. Functional neuroimaging was used to assess brain response to food images among groups of overweight (OW), normal-weight (NW), and successful weight-losing (SWL) adolescents. Eleven SWL, 12 NW, and 11 OW participants underwent functional magnetic resonance imaging while viewing images of high- and low-energy foods. When viewing high-energy food images, SWLs demonstrated greater activation in the dorsolateral prefrontal cortex (DLPFC) compared with OW and NW controls. Compared with NW and SWL groups, OW individuals demonstrated greater activation in the ventral striatum and anterior cingulate in response to food images. Adolescent SWLs demonstrated greater neural activation in the DLPFC compared with OW/NW controls when viewing high-energy food stimuli, which may indicate enhanced executive control. OW individuals' brain responses to food stimuli may indicate greater reward incentive processes than either SWL or NW groups. © 2015 The Obesity Society.

  19. Comparative study between the Spin-echo and 3-D fast imaging techniques in the Knee evaluation with magnetic resonance. Estudio comparativo entre las tecnicas de Spin-Eco ecogradiente 3D, en la evaluacion de la rodilla con resonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Oleaga Zufiria, L.; Ibaez Zubiarrain, A.; Grande Icaran, J.; Vela Martin, A.C.; Cintora Leon, E.; Grau Garcia, M.; Grande Icaran, D. (Hospital Civil de Bilbao. Servicio de Radiodiagnostico. Bilbao (Spain))

    1993-01-01

    We have carried out a retrospective analysis of the results of magnetic resonance (MR) studies in 20 patients, comparing two different sequences. We compared a 2-D spin-echo (SE2D) sequence with a 3-D fast imaging with steady-state precession (FISP3D) sequence in the attempt to compare the reliability of each in the detection of knee injuries. Arthroscopy was employed as a control technique. Our study revealed no statistically significant difference between the two sequences, although the overall sensitivity for the detection of meniscal lesions was slightly greater with the FISP3D sequence; however, the reliability in the detection of ruptures of the posterior cruciate ligament is less with this sequence than with the SE2D sequence. Both sequences showed very low sensitivity in the detection of hyaline cartilage injuries. (Author) 14 refs.

  20. Comparative study of connectivity in telemedicine.

    Science.gov (United States)

    Singh, Indra Pratap; Kapoor, Lily; Daman, Repu; Mishra, Saroj Kanta

    2008-10-01

    Communication links are the lifelines for telemedicine practice. Various terrestrial and satellite media can be used; however, each has its own plus and minus side. The current study was designed to evaluate three types of telecommunication media used for telemedical videoconference at the Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow Telemedicine program over a period of 20 months. The evaluation was based on analysis of technical parameters recorded in a prescribed proforma designed for the study purpose and maintained prospectively after completion of each event. Only technical issues were addressed. At the end of the study period, analysis of data revealed that leased line-based terrestrial Internet Protocol (IP) was better than Sky IP. Integrated Services Digital Network media were found technically less acceptable for telemedical videoconference.

  1. Child Labor in Africa: A Comparative Study

    DEFF Research Database (Denmark)

    Canagarajah, Sudharshan; Nielsen, Helena Skyt

    2001-01-01

    This paper analyzes the determinants of child labor in Africa as inferred from recent empirical studies. The empirical analysis is based upon five country studies undertaken in three different African countries, namely Côte d'Ivoire, Ghana, and Zambia. Some support is found for the popular belief...... of poverty as a determinant of child labor, however other determinants are of similar importance. Among school costs, transportation costs have the greatest effect on child labor and school attendance, whereas the hypothesis of imperfect capital markets and that of household composition generally find some...

  2. Child Labor in Africa: A Comparative Study

    DEFF Research Database (Denmark)

    Nielsen, Helena Skyt; Canagarajah, Sudharshan

    1999-01-01

    This paper analyzes the determinants of child labor in Africa as inferred from recent empirical studies. The empirical analysis is based upon five country studies undertaken in three different African countries, namely Côte d'Ivoire, Ghana, and Zambia. Some support is found for the popular belief...... of poverty as a determinant of child labor, however other determinants are of similar importance. Among school costs, transportation costs have the greatest effect on child labor and school attendance, whereas the hypothesis of imperfect capital markets and that of household composition generally find some...

  3. Potential for observing and discriminating impact craters and comparable volcanic landforms on Magellan radar images

    International Nuclear Information System (INIS)

    Ford, J.P.

    1989-01-01

    Observations of small terrestrial craters by Seasat synthetic aperture radar (SAR) at high resolution (approx. 25 m) and of comparatively large Venusian craters by Venera 15/16 images at low resolution (1000 to 2000 m) and shorter wavelength show similarities in the radar responses to crater morphology. At low incidence angles, the responses are dominated by large scale slope effects on the order of meters; consequently it is difficult to locate the precise position of crater rims on the images. Abrupt contrasts in radar response to changing slope (hence incidence angle) across a crater produce sharp tonal boundaries normal to the illumination. Crater morphology that is radially symmetrical appears on images to have bilateral symmetry parallel to the illumination vector. Craters are compressed in the distal sector and drawn out in the proximal sector. At higher incidence angles obtained with the viewing geometry of SIR-A, crater morphology appears less compressed on the images. At any radar incidence angle, the distortion of a crater outline is minimal across the medial sector, in a direction normal to the illumination. Radar bright halos surround some craters imaged by SIR-A and Venera 15 and 16. The brightness probably denotes the radar response to small scale surface roughness of the surrounding ejecta blankets. Similarities in the radar responses of small terrestrial impact craters and volcanic craters of comparable dimensions emphasize the difficulties in discriminating an impact origin from a volcanic origin in the images. Similar difficulties will probably apply in discriminating the origin of small Venusian craters, if they exist. Because of orbital considerations, the nominal incidence angel of Magellan radar at the center of the imaging swath will vary from about 45 deg at 10 deg N latitude to about 16 deg at the north pole and at 70 deg S latitude. Impact craters and comparable volcanic landforms will show bilateral symmetry

  4. Comparative Anticonvulsant Study of Epoxycarvone Stereoisomers

    Directory of Open Access Journals (Sweden)

    Paula Regina Rodrigues Salgado

    2015-10-01

    Full Text Available Stereoisomers of the monoterpene epoxycarvone (EC, namely (+-cis-EC, (−-cis-EC, (+-trans-EC, and (−-trans-EC, were comparatively evaluated for anticonvulsant activity in specific methodologies. In the pentylenetetrazole (PTZ-induced anticonvulsant test, all of the stereoisomers (at 300 mg/kg increased the latency to seizure onset, and afforded 100% protection against the death of the animals. In the maximal electroshock-induced seizures (MES test, prevention of tonic seizures was also verified for all of the isomers tested. However, the isomeric forms (+ and (−-trans-EC showed 25% and 12.5% inhibition of convulsions, respectively. In the pilocarpine-induced seizures test, all stereoisomers demonstrated an anticonvulsant profile, yet the stereoisomers (+ and (−-trans-EC (at 300 mg/kg showed a more pronounced effect. A strychnine-induced anticonvulsant test was performed, and none of the stereoisomers significantly increased the latency to onset of convulsions; the stereoisomers probably do not act in this pathway. However, the stereoisomers (+-cis-EC and (+-trans-EC greatly increased the latency to death of the animals, thus presenting some protection. The four EC stereoisomers show promise for anticonvulsant activity, an effect emphasized in the isomers (+-cis-EC, (+-trans-EC, and (−-trans-EC for certain parameters of the tested methodologies. These results serve as support for further research and development of antiepileptic drugs from monoterpenes.

  5. Comparative study on software development methodologies

    Directory of Open Access Journals (Sweden)

    Mihai Liviu DESPA

    2014-12-01

    Full Text Available This paper focuses on the current state of knowledge in the field of software development methodologies. It aims to set the stage for the formalization of a software development methodology dedicated to innovation orientated IT projects. The paper starts by depicting specific characteristics in software development project management. Managing software development projects involves techniques and skills that are proprietary to the IT industry. Also the software development project manager handles challenges and risks that are predominantly encountered in business and research areas that involve state of the art technology. Conventional software development stages are defined and briefly described. Development stages are the building blocks of any software development methodology so it is important to properly research this aspect. Current software development methodologies are presented. Development stages are defined for every showcased methodology. For each methodology a graphic representation is illustrated in order to better individualize its structure. Software development methodologies are compared by highlighting strengths and weaknesses from the stakeholder's point of view. Conclusions are formulated and a research direction aimed at formalizing a software development methodology dedicated to innovation orientated IT projects is enunciated.

  6. Toucan and hornbill beaks: a comparative study.

    Science.gov (United States)

    Seki, Yasuaki; Bodde, Sara G; Meyers, Marc A

    2010-02-01

    The structure and mechanical behavior of Toco Toucan (Ramphastos toco) and Wreathed Hornbill (Rhyticeros undulatus) beaks were compared. The beak of both species is a sandwich-structured composite, having an exterior, or rhamphotheca, consisting of multiple layers of keratin scales and a core composed of a fibrous network of bony closed-cell foam. The rhamphotheca is an arrangement of approximately 50microm diameter, overlapping, keratin tiles. The hornbill rhamphotheca exhibits a surface morphology on the ridged casque that is distinguishable from that observed on the bill proper. Intermediate filaments in the keratin matrix were observed by transmission electron microscopy. The Young's modulus measurements of toucan rhamphotheca indicate isotropy in longitudinal and transverse directions, whereas those of hornbill rhamphotheca may suggest anisotropy. The compressive response of beak foam is governed by brittle crushing behavior. The crushing strength of hornbill foam is six times higher than that of toucan foam. Micro- and nanoindentation hardness values were measured for rhamphotheca and foam trabeculae of toucan and hornbill specimens. The sandwich design of beaks was analyzed using the Karam-Gibson and Dawson-Gibson models. The presence of a cellular core increases the bending resistance (Brazier moment) by a factor of 3-6 while decreasing the compressive strength by only 50%.

  7. Comparative study of two treatment planning systems

    International Nuclear Information System (INIS)

    Ramos Caballero, L. J.; Quinones Rodriguez, L. A.; Lupiani Castellanos, J.

    2013-01-01

    In this study of the comparison of the clinical dosimetry between planners can deduce that the differences are in the majority of the cases below 3%, and only in cases where the field size is small, we found significant discrepancies, although justifiable. On the one hand it is different calculation algorithm and implementation on the other, the modeling of the accelerator. (Author)

  8. COMPARATIVE STUDY OF CONSERVATIVE RESECTION AND ...

    African Journals Online (AJOL)

    1999-05-05

    May 5, 1999 ... Depmment of Surgery, University Teaching Hospital, PMB 2076. Jos, Nigeria ... Design: A retrospective study of patients with thyroid cancers that were managed during an ... This logical basis for either cure or palliation of a .... palliative purposes. A mixed ... Pulmonary metastasis are usually of the classical.

  9. Metacognition and Group Differences: A Comparative Study

    Science.gov (United States)

    Al-Hilawani, Yasser A.

    2014-01-01

    In this study, metacognition refers to performing visual analysis and discrimination of real life events and situations in naïve psychology, naïve physics, and naïve biology domains. It is used, along with measuring reaction time, to examine differences in the ability of four groups of students to select appropriate pictures that correspond with…

  10. Children's Friendship Development: A Comparative Study

    Science.gov (United States)

    Yu, SeonYeong; Ostrosky, Michaelene M.; Fowler, Susan A.

    2011-01-01

    Establishing friendships is an important developmental goal of early childhood, but little research has addressed ways in which parents support the friendship development of their young children with disabilities. The purpose of this survey study was to explore the support strategies that parents use to facilitate their children's friendships.…

  11. Earthquake correlations and networks: A comparative study

    Science.gov (United States)

    Krishna Mohan, T. R.; Revathi, P. G.

    2011-04-01

    We quantify the correlation between earthquakes and use the same to extract causally connected earthquake pairs. Our correlation metric is a variation on the one introduced by Baiesi and Paczuski [M. Baiesi and M. Paczuski, Phys. Rev. E EULEEJ1539-375510.1103/PhysRevE.69.06610669, 066106 (2004)]. A network of earthquakes is then constructed from the time-ordered catalog and with links between the more correlated ones. A list of recurrences to each of the earthquakes is identified employing correlation thresholds to demarcate the most meaningful ones in each cluster. Data pertaining to three different seismic regions (viz., California, Japan, and the Himalayas) are comparatively analyzed using such a network model. The distribution of recurrence lengths and recurrence times are two of the key features analyzed to draw conclusions about the universal aspects of such a network model. We find that the unimodal feature of recurrence length distribution, which helps to associate typical rupture lengths with different magnitude earthquakes, is robust across the different seismic regions. The out-degree of the networks shows a hub structure rooted on the large magnitude earthquakes. In-degree distribution is seen to be dependent on the density of events in the neighborhood. Power laws, with two regimes having different exponents, are obtained with recurrence time distribution. The first regime confirms the Omori law for aftershocks while the second regime, with a faster falloff for the larger recurrence times, establishes that pure spatial recurrences also follow a power-law distribution. The crossover to the second power-law regime can be taken to be signaling the end of the aftershock regime in an objective fashion.

  12. Earthquake correlations and networks: A comparative study

    International Nuclear Information System (INIS)

    Krishna Mohan, T. R.; Revathi, P. G.

    2011-01-01

    We quantify the correlation between earthquakes and use the same to extract causally connected earthquake pairs. Our correlation metric is a variation on the one introduced by Baiesi and Paczuski [M. Baiesi and M. Paczuski, Phys. Rev. E 69, 066106 (2004)]. A network of earthquakes is then constructed from the time-ordered catalog and with links between the more correlated ones. A list of recurrences to each of the earthquakes is identified employing correlation thresholds to demarcate the most meaningful ones in each cluster. Data pertaining to three different seismic regions (viz., California, Japan, and the Himalayas) are comparatively analyzed using such a network model. The distribution of recurrence lengths and recurrence times are two of the key features analyzed to draw conclusions about the universal aspects of such a network model. We find that the unimodal feature of recurrence length distribution, which helps to associate typical rupture lengths with different magnitude earthquakes, is robust across the different seismic regions. The out-degree of the networks shows a hub structure rooted on the large magnitude earthquakes. In-degree distribution is seen to be dependent on the density of events in the neighborhood. Power laws, with two regimes having different exponents, are obtained with recurrence time distribution. The first regime confirms the Omori law for aftershocks while the second regime, with a faster falloff for the larger recurrence times, establishes that pure spatial recurrences also follow a power-law distribution. The crossover to the second power-law regime can be taken to be signaling the end of the aftershock regime in an objective fashion.

  13. Conjunctivitis in the newborn- A comparative study

    Directory of Open Access Journals (Sweden)

    Meenakshi Wadhwani

    2011-01-01

    Full Text Available Background: Conjunctivitis of the newborn is defined as hyperemia and eye discharge in the neonates and is a common infection occurring in the neonates in the first month of life. In the United States, the incidence of neonatal conjunctivitis ranges from 1-2%, in India, the prevalence is 0.5-33% and varies in the world from 0.9-21% depending on the socioeconomic status. Aim: To study the organisms causing conjunctivitis of the newborn and to correlate the etiology with the mode of delivery. Design: Single center, prospective, observational study. Materials and Methods: A total of 300 mothers and their newborns, born over a period of one year, were included in the study. Of these 200 newborns were delivered through vaginal route (Group A and 100 (Group B delivered by lower segment caesarean section (LSCS. At the time of labour, high vaginal swabs were taken from the mothers. Two conjunctival swabs each from both eyes of the newborn were collected at birth and transported to Microbiology department in a candle jar immediately. Results: Eight babies in Group A, developed conjunctivitis at birth. None of the babies in Group B developed conjunctivitis, this difference was statistically highly significant (P<0.000. The organisms found in the conjunctiva of the newborns in Group A were Coagulase negative Staphylococcus, α hemolytic Streptococcus, Escherichia coli and Pseudomonas spps. However, the commonest organism leading to conjunctivitis in the newborn in this study was Coagulase negative Staphylococcus. It was observed that the mothers of 5 out of 8 babies (60% developing conjunctivitis gave history of midwife interference and premature rupture of membranes so the presence of risk factors contribute to the occurrence of conjunctivitis in the newborn. Conclusions: It is inferred that the mode of delivery and the presence of risk factors is responsible for conjunctivitis in the newborn.

  14. Comparative study of radon in Sudan

    International Nuclear Information System (INIS)

    Gharbi, Shaza Ismail Mohammed

    2014-07-01

    This study was conducted primarily to contribute radon data for radon map in Sudan and identify regions with elevated radon levels and improve data collection and analysis for the future radon levels evaluation. This study partially covered three states of Sudan ( Red Sea - Khartoum - South Khordofan). Previous work done has been considered in this study which focused and investigated the levels of radon concentration in ( indoor radon gas and water) by using gamma spectrometry equipped with ( HPGe detector) or (Na1 (T1) detector). The results obtained are within the acceptable levels and dose not poses any risk from radiation protection point of view. Red Sea state ( port-sudan): (124.39±6.21) Bq/m 3 . Khartoum state ( Suba): (151.52) Bq/m 3 . (Omdurman): ( 127±23) Bq/m 3 . Radon in water: (59) Bq/L. South Kordofan State: (102.8) Bq/m 3 . In water (Kadugli): (3 1 39)) Bq/L.(Author)

  15. A comparative study of various decalcification techniques

    Directory of Open Access Journals (Sweden)

    Prathibha Prasad

    2013-01-01

    Full Text Available Background : Study of fibrilar, cellular and sub cellular structures of mineralized tissues is only possible after the removal of the calcium apatite of these tissues by the process of demineralization. Aims: The present study aims to evaluate six commonly used demineralizing agents to identify the best decalcifying agent. Materials and Methods: The present study included six different decalcifying solutions: 10% formal nitric acid, 8% formal nitric acid, 10% formic acid, 8% formic acid, Perenyi′s fluid and Ethylene Di-Amine Tetra Acetic Acid. eight samples of posterior mandible of rat were decalcified in each of the decalcifying solutions and subjected to chemical end-point test. Ehrlich′s Hematoxylin stain was used. Statistical Analysis Used: One way ANOVA was used for multiple group comparisons and Chi-square test was used for analyzing categorical data. P value of 0.05/less was set for statistical significance. Results: Samples treated with EDTA showed the best overall histological impression and the tissue integrity were well preserved. Formal nitric of both the percentages 10 and 8% gave fairly good cellular detail and were rapid in their action. Conclusion: The final impression led to the proposition that EDTA was indeed the best decalcifying agent available. However, with time constraint, the use of formal nitric acid is advocated.

  16. Agoraphobia and Panic Disorder: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Ayse Kart

    2016-01-01

    Full Text Available Aim: In this study we aim to get more information about agoraphobia (AG which is an independent diagnosis in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5 and to evaluate overlaps or differences between agoraphobia and panic disorder (PD upon sociodemographic features and comorbidity with considering relation of these two disorders. Material and Method: Sociodemographic Data Form was given and Structural Clinical Interview for DSM Axis I Disorders (SCID-I was applied to 33 patients diagnosed as AG and 34 patients diagnosed as PD with AG (PDA.Results: AG group consisted of 21 females (63.1%, 12 males (36%, totally 33 patients and PDA group consisted of 23 females (67.6%, 11 males (32.4%, totally 34 patients. Mean age of onset was 32.4±10.2 in PDA group and 31.1±12.1 in AG group. According to sociodemographic features, violence in family and smoking rates were significantly higher in PDA group than AG group. Major Depressive Disorder (MDD as a comorbidity was higher in PDA group. Discussion: In this study, we tried to identify the overlaps and differences of PDA and AG. For a better recognition of AG, further studies are needed.

  17. Comparative anatomy of rabbit and human achilles tendons with magnetic resonance and ultrasound imaging.

    Science.gov (United States)

    Doherty, Geoffrey P; Koike, Yoichi; Uhthoff, Hans K; Lecompte, Martin; Trudel, Guy

    2006-02-01

    We sought to describe the comparative anatomy of the Achilles tendon in rabbits and humans by using macroscopic observation, magnetic resonance imaging, and ultrasonography. The calcaneus-Achilles tendon-gastrocnemius-soleus complexes from 18 New Zealand white rabbits underwent ultrasound (US) and magnetic resonance (MR) imaging and gross anatomic sectioning; these results were compared with those from a cadaveric gastrocnemius-soleus-Achilles tendon-calcaneus specimen from a 68-y-old human male. The medial and lateral gastrocnemius muscle tendons merged 5.2 +/- 0.6 mm proximal to the calcaneal insertion macroscopically, at 93% of their course, different from the gastrocnemius human tendons, which merged at 23% of their overall course. The rabbit flexor digitorum superficialis tendon, corresponding to the flexor digitorum longus tendon in human and comparable in size with the gastrocnemius tendons, was located medial and anterior to the medial gastrocnemius tendon proximally and rotated dorsally and laterally to run posterior to the Achilles tendon-calcaneus insertion. In humans, the flexor digitorum longus tendon tracks posteriorly to the medial malleolus. The soleus muscle and tendon are negligible in the rabbit; these particular comparative anatomic features in the rabbit were confirmed on the MR images. Therefore the rabbit Achilles tendon shows distinctive gross anatomical and MR imaging features that must be considered when using the rabbit as a research model, especially for mechanical testing, or when generalizing results from rabbits to humans.

  18. A Study on the Improvement of Digital Periapical Images using Image Interpolation Methods

    International Nuclear Information System (INIS)

    Song, Nam Kyu; Koh, Kwang Joon

    1998-01-01

    Image resampling is of particular interest in digital radiology. When resampling an image to a new set of coordinate, there appears blocking artifacts and image changes. To enhance image quality, interpolation algorithms have been used. Resampling is used to increase the number of points in an image to improve its appearance for display. The process of interpolation is fitting a continuous function to the discrete points in the digital image. The purpose of this study was to determine the effects of the seven interpolation functions when image resampling in digital periapical images. The images were obtained by Digora, CDR and scanning of Ektaspeed plus periapical radiograms on the dry skull and human subject. The subjects were exposed to intraoral X-ray machine at 60 kVp and 70 kVp with exposure time varying between 0.01 and 0.50 second. To determine which interpolation method would provide the better image, seven functions were compared ; (1) nearest neighbor (2) linear (3) non-linear (4) facet model (5) cubic convolution (6) cubic spline (7) gray segment expansion. And resampled images were compared in terms of SNR (Signal to Noise Ratio) and MTF (Modulation Transfer Function) coefficient value. The obtained results were as follows ; 1. The highest SNR value (75.96 dB) was obtained with cubic convolution method and the lowest SNR value (72.44 dB) was obtained with facet model method among seven interpolation methods. 2. There were significant differences of SNR values among CDR, Digora and film scan (P 0.05). 4. There were significant differences of MTF coefficient values between linear interpolation method and the other six interpolation methods (P<0.05). 5. The speed of computation time was the fastest with nearest neighbor method and the slowest with non-linear method. 6. The better image was obtained with cubic convolution, cubic spline and gray segment method in ROC analysis. 7. The better sharpness of edge was obtained with gray segment expansion method

  19. Uterine leiomyoma: comparative study with MRI and histopathology

    International Nuclear Information System (INIS)

    Zhang Rong; Liang Biling; Fu Jiaping; Li Yong; Shen Jun

    2003-01-01

    Objective: To compare MRI findings of uterine leiomyomas with histologic subtypes, and to evaluate the value of enhanced MRI in differentiating leiomyoma subtypes. Methods: Forty-two cases of uterine leiomyomas with MRI and pathology were analyzed between 1998 and 2002. 101 uterine leiomyomas were analyzed. 34 cases were examined with Philips T5-II super-conducting magnetic resonance system (0.5T) using surface coil and 8 cases with Philips Intera 1.5 T super-conducting magnetic resonance system using body phase array coil. Plain scan were acquired with SE T 1 -weighted imaging and TSE T 2 -weighted imaging. Conventional contrast imaging was obtained with SE T 1 -weighted imaging after iv injection of Gd-DTPA (0.1mmol/kg). MR features were observed and compared with that of the pathological types. Results: Almost all the leiomyomas showed slight hypointensity or isointensity on T 1 -weighted images. Most ordinary (97%) leiomyomas displayed hypointensity on T 2 -weighted images. Most cellular (75%) and degenerated (55%) leiomyomas manifested as hyperintensity on T 2 -weighted images. The signal intensity was not statistically different between cellular leiomyomas and degenerated leiomyomas (χ 2 =4.192, P>0.05). However, there was a statistically significant difference in the signal intensity on T 2 -weighted images between ordinary leiomyomas and cellular or degenerated leiomyomas (χ 2 =81.564, P<0.05). The signal homogeneity was statistically different in leiomyomas among different pathological types. Three patterns of enhancement occurred in ordinary leiomyomas, but mostly showed homogeneously enhanced. Most cellular leiomyomas showed homogenous enhancement, the degenerated leiomyomas mostly displayed peripheral and mild enhancement. Conclusion: The signal intensity on MR imaging was different in leiomyomas with different pathological subtype. The Gd-DTPA enhanced scans was not indispensable for the diagnosis and detection of leiomyomas, but it can help to

  20. Comparative value of diagnostic imaging techniques in a cat with exophthalmos

    International Nuclear Information System (INIS)

    Ramsey, D.T.; Gerding, P.A. Jr.; Losonsky, J.M.; Kuriashkin, I.V.; Clarkson, R.D.

    1994-01-01

    A mass that appeared to originate from the frontal bone and extended into retrobulbar tissues of the light orbit was imaged in a cat using ultrasound, skull radiographs, computed tomography, and magnetic resonance imaging. The cat was presented with ventrolateral strabismus, exophthalmos, and elevated nictitans membrane of the tight eye. The mass was not delineated entirely after orbital echography and survey radiography of the skull was performed. Cytologic examination of fine-needle aspirate of the mass was suggestive of a neoplastic disease. Results of computed tomography indicated lysis of the calvarium but did not delineate borders of the mass in the calvarium. Magnetic resonance imaging was then used to confirm borders of the neoplasm. Magnetic resonance imaging was the only imaging technique that delineated the entire border of the neoplasm, including in the calvarium, when compared to postmortem evaluation. Results of orbital echography, skull radiographs, or computed tomography, when used as the only diagnostic imaging modality, must be interpreted with caution when evaluating borders of retrobulbar neoplasia prior to surgical planning

  1. Comparative Accuracy of Facial Models Fabricated Using Traditional and 3D Imaging Techniques.

    Science.gov (United States)

    Lincoln, Ketu P; Sun, Albert Y T; Prihoda, Thomas J; Sutton, Alan J

    2016-04-01

    The purpose of this investigation was to compare the accuracy of facial models fabricated using facial moulage impression methods to the three-dimensional printed (3DP) fabrication methods using soft tissue images obtained from cone beam computed tomography (CBCT) and 3D stereophotogrammetry (3D-SPG) scans. A reference phantom model was fabricated using a 3D-SPG image of a human control form with ten fiducial markers placed on common anthropometric landmarks. This image was converted into the investigation control phantom model (CPM) using 3DP methods. The CPM was attached to a camera tripod for ease of image capture. Three CBCT and three 3D-SPG images of the CPM were captured. The DICOM and STL files from the three 3dMD and three CBCT were imported to the 3DP, and six testing models were made. Reversible hydrocolloid and dental stone were used to make three facial moulages of the CPM, and the impressions/casts were poured in type IV gypsum dental stone. A coordinate measuring machine (CMM) was used to measure the distances between each of the ten fiducial markers. Each measurement was made using one point as a static reference to the other nine points. The same measuring procedures were accomplished on all specimens. All measurements were compared between specimens and the control. The data were analyzed using ANOVA and Tukey pairwise comparison of the raters, methods, and fiducial markers. The ANOVA multiple comparisons showed significant difference among the three methods (p 3D-SPG showed statistical difference in comparison to the models fabricated using the traditional method of facial moulage and 3DP models fabricated from CBCT imaging. 3DP models fabricated using 3D-SPG were less accurate than the CPM and models fabricated using facial moulage and CBCT imaging techniques. © 2015 by the American College of Prosthodontists.

  2. Brain imaging studies of sleep disorder

    International Nuclear Information System (INIS)

    Nakamura, Masaki; Inoue, Yuichi

    2014-01-01

    Brain imaging studies of narcolepsy (NA)/cataplexy (CA), a typical sleep disorder, are summarized together with techniques of functional and structural imaging means. single photon emission CT (SPECT) is based on the distribution of tracers labeled by single photon emitters like 99m Tc and 123 I for seeing the blood flow and receptors. PET using positron emitters like 15 O and 18 F for blood flow and for glucose metabolism, respectively, is of higher resolution and more quantitative than SPECT. Functional MRI (fMRI) depicts the cerebral activity through signal difference by blood oxygenation level dependence (BOLD) effect, and MR spectroscopy (MRS) depicts and quantifies biomaterials through the difference of their nuclear chemical shifts in the magnetic field. Morphologic imaging studies involve the measurement of the volume of the region of interest by comparison with the reference region such as the whole brain volume. Voxel-based morphometry (VBM) has changed to its more advanced surface-based analysis (SBA) of T1-enhanced image. Diffusion tensor imaging (DTI) is based on the tissue water diffusion. Functional SPECT/PET studies have suggested the decrease of blood flow and metabolic activity in the hypothalamus (HT) and other related regions at the conscious resting state, and locally increased blood flow in cingulate gyrus (CG) and amygdaloid complex (AC) at affective CA/PA seizure. fMRI has suggested the hypoactivity of HT and hyperactivity of AC at the seizure. VBM-based studies have not given the consistent results, but DTI studies have suggested an important participation of AC at the seizure. (T.T.)

  3. Study of TCP densification via image analysis

    International Nuclear Information System (INIS)

    Silva, R.C.; Alencastro, F.S.; Oliveira, R.N.; Soares, G.A.

    2011-01-01

    Among ceramic materials that mimic human bone, β-type tri-calcium phosphate (β-TCP) has shown appropriate chemical stability and superior resorption rate when compared to hydroxyapatite. In order to increase its mechanical strength, the material is sintered, under controlled time and temperature conditions, to obtain densification without phase change. In the present work, tablets were produced via uniaxial compression and then sintered at 1150°C for 2h. The analysis via XRD and FTIR showed that the sintered tablets were composed only by β-TCP. The SEM images were used for quantification of grain size and volume fraction of pores, via digital image analysis. The tablets showed small pore fraction (between 0,67% and 6,38%) and homogeneous grain size distribution (∼2μm). Therefore, the analysis method seems viable to quantify porosity and grain size. (author)

  4. Experimental study of bubbly flow using image processing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yucheng, E-mail: ycfu@vt.edu; Liu, Yang, E-mail: liu130@vt.edu

    2016-12-15

    This paper presents an experimental study of bubbly flows at relatively high void fractions using an advanced image processing method. Bubble overlapping is a common problem in such flows and the past studies often treat the overlapping bubbles as a whole, which introduces considerable measurement uncertainties. In this study, a hybrid method combining intersection point detection and watershed segmentation is used to separate the overlapping bubbles. In order to reconstruct bubbles from separated segments, a systematic procedure is developed which can preserve more features captured in the raw image compared to the simple ellipse fitting method. The distributions of void fraction, interfacial area concentration, number density and velocity are obtained from the extracted bubble information. High-speed images of air-water bubbly flows are acquired and processed for eight test runs conducted in a 30 mm × 10 mm rectangular channel. The developed image processing scheme can effectively separate overlapping bubbles and the results compare well with the measurements by the gas flow meter and double-sensor conductivity probe. The development of flows in transverse and mainstream directions are analyzed and compared with the prediction made by the one-dimensional interfacial area transport equation (IATE) and the bubble number density transport equation.

  5. Comparative methods for quantifying thyroid volume using planar imaging and SPECT

    International Nuclear Information System (INIS)

    Zaidi, H.

    1996-01-01

    Thyroid volume determination using planar imaging is a procedure often performed in routine nuclear medicine, but is hampered by several physical difficulties, in particular by structures which overlie or underlie the organ of interest. SPECT enables improved accuracy over planar imaging in the determination of the volume since it is derived from the 3-D data rather than from a 2-D projection with a certain geometric assumption regarding the thyroid configuration. By using the phantoms of known volume, it was possible to estimate the accuracy of 3 different methods of determining thyroid volume from planar imaging used in clinical routine. The experimental results demonstrate that compared with conventional scintigraphy, thyroid phantom volumes were most accurately determined with SPECT when attenuation and scatter corrections are performed which allows accurate radiation dosimetry in humans without the need for assumptions on organ size or concentrations. Poster 181. (author)

  6. [Comparation on Haversian system between human and animal bones by imaging analysis].

    Science.gov (United States)

    Lu, Hui-Ling; Zheng, Jing; Yao, Ya-Nan; Chen, Sen; Wang, Hui-Pin; Chen, Li-Xian; Guo, Jing-Yuan

    2006-04-01

    To explore the differences in Haversian system between human and animal bones through imaging analysis and morphology description. Thirty-five slices grinding from human being as well as dog, pig, cow and sheep bones were observed to compare their structure, then were analysed with the researchful microscope. Plexiform bone or oeston band was not found in human bones; There were significant differences in the shape, size, location, density of Haversian system, between human and animal bones. The amount of Haversian lamella and diameter of central canal in human were the biggest; Significant differences in the central canal diameter and total area percentage between human and animal bones were shown by imaging analysis. (1) Plexiform bone and osteon band could be the exclusive index in human bone; (2) There were significant differences in the structure of Haversian system between human and animal bones; (3) The percentage of central canals total area was valuable in species identification through imaging analysis.

  7. Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance.

    Science.gov (United States)

    Sveistrup, Joen; af Rosenschöld, Per Munck; Deasy, Joseph O; Oh, Jung Hun; Pommer, Tobias; Petersen, Peter Meidahl; Engelholm, Svend Aage

    2014-02-04

    Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1-2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5-7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction.

  8. Educational effect of a lecture on differential imaging features comparing ameloblastomas and keratocystic odontogenic tumors of the mandible presented to dental students

    International Nuclear Information System (INIS)

    Morita, Mitsuko; Ariji, Yoshiko; Kise, Yoshitaka; Goto, Masakazu; Izumi, Masahiro; Naitoh, Munetaka; Ariji, Eiichiro; Katsumata, Akitoshi

    2011-01-01

    The objective of this study was to clarify the educational effect of a lecture on differential imaging features comparing ameloblastomas and keratocystic odontogenic tumors of the mandibles presented to dental students. Panoramic and CT images of 10 ameloblastomas and 10 keratocystic odontogenic tumors were randomly presented 114 dental students. Test scores, correct answer ratios, identification index, and understanding of the imaging features contributing to a correct diagnosis were serially evaluated before and after the lecture on the differential imaging features comparing the two types of tumors. The mean and standard deviation of the scoring ratios of dental students diagnosing these lesions on panoramic and CT images were 48.8±10.8% and 52.5±12.9%, respectively. After the lecture on the differential imaging features comparing the two tumors, the scoring ratios improved significantly. After the lecture, both the numbers of patients whose images were correctly diagnosed and the identification indices increased. The lecture also increased the number of imaging features recognized as contributing to the correct diagnosis. A lecture on the differential imaging features comparing ameloblastomas and keratocystic odontogenic tumors of the mandibles contributed to the improvement of imaging diagnosis skills among dental students. (author)

  9. Comparative diagnostic imaging of a partial patellar ligament tear in a dog

    Directory of Open Access Journals (Sweden)

    Mario Ricciardi

    2018-05-01

    Full Text Available Traumatic lesions of the patellar ligament (PL are rare in dogs. The resulting injury can be a complete or partial laceration, depending on the quantity of torn collagen fibres. Information obtained from imaging evaluation is of great value to the clinical approach towards PL injuries, because subsequent treatment options are affected by the distinction between complete or partial tears. Imaging diagnosis of PL damage in veterinary practice commonly relies on radiographic examination through the recognition of indirect signs, such as “patella alta”, bone fragments at the level of the patellar or tibial insertion, and soft tissue opacity at the cranial aspect of the joint. Although ultrasound (US and magnetic resonance imaging (MRI have been described as useful diagnostic tools for the assessment of PL tears in human patients, specific comparative data regarding the evaluation of PL rupture in dogs using different imaging modalities is lacking in the veterinary literature. This paper describes the radiographic, ultrasonographic, CT and MRI imaging findings of a partial PL tear in a dog and discusses the utility of these techniques in diagnosing this condition. CT provided more detailed information than X-ray examination in the assessment of the osteoligamentous junction, the exclusion of microfracture and distal PL avulsion, but did not add information regarding PL integrity. MRI and US provided the most useful information regarding intra-ligamentous damage and as such their combined use may be considered for the assessment of PL injuries after clinical examination and survey radiographs.

  10. Ultrasonography of symptomatic rotator cuff tears compared with MR imaging and surgery

    International Nuclear Information System (INIS)

    Fotiadou, Anastasia N.; Vlychou, Marianna; Papadopoulos, Periklis; Karataglis, Dimitrios S.; Palladas, Panagiotis; Fezoulidis, Ioannis V.

    2008-01-01

    Purpose: To compare the accuracy of ultrasonography and magnetic resonance imaging