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Sample records for mri grading method

  1. MRI grading method for active and chronic spinal changes in spondyloarthritis

    International Nuclear Information System (INIS)

    Madsen, K.B.; Jurik, A.G.

    2010-01-01

    Aim: To describe a magnetic resonance imaging (MRI) grading method for both active and chronic spondyloarthritis (SpA) changes in the spine, to test its validity, and compare chronic MRI scores with findings obtained by radiography. Material and methods: A total of 91 patients (41 males; 50 females) with back pain fulfilling the European Spondylarthropathy Study Group (ESSG) criteria for SpA were examined using MRI and radiography of the spine. The mean age was 36.7 years (range 16-51 years) and symptom duration was between 3 and 27 years. The MRI images were assessed for signs of disease activity (bone marrow oedema at the vertebral plates and costo-vertebral joints) and chronic structural changes [syndesmophytes/vertebral fusion, erosion, and fatty marrow deposition (FMD)]. The interobserver agreement was analysed based on 37 examinations. Radiographs were assessed for the presence of shiny corners, vertebral squaring, syndesmophytes/fusion, and erosion. Results: The interobserver agreement for the assessed MRI abnormalities was acceptable, with kappa values between 0.62 and 0.77. A total of 56 patients had SpA-related spinal abnormalities as depicted using MRI. The total chronic MRI score was not significantly related to the radiographic score, mainly because syndesmophytes were difficult to detect by MRI and FMD was only visualized by MRI. However, FMD was significantly related to the total radiographic score and vertebral squaring. Conclusion: The described MRI grading method was reliable for assessing both disease activity and chronic changes. MRI is promising for estimating chronic changes, but cervical radiography may still be needed. FMD seems to be an important sign of chronicity.

  2. MRI grading method for active and chronic spinal changes in spondyloarthritis

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    Madsen, K.B. [Department of Radiology, Aarhus University Hospital, Aarhus Sygehus (Denmark); Jurik, A.G., E-mail: anne.jurik@aarhus.rm.d [Department of Radiology, Aarhus University Hospital, Aarhus Sygehus (Denmark)

    2010-01-15

    Aim: To describe a magnetic resonance imaging (MRI) grading method for both active and chronic spondyloarthritis (SpA) changes in the spine, to test its validity, and compare chronic MRI scores with findings obtained by radiography. Material and methods: A total of 91 patients (41 males; 50 females) with back pain fulfilling the European Spondylarthropathy Study Group (ESSG) criteria for SpA were examined using MRI and radiography of the spine. The mean age was 36.7 years (range 16-51 years) and symptom duration was between 3 and 27 years. The MRI images were assessed for signs of disease activity (bone marrow oedema at the vertebral plates and costo-vertebral joints) and chronic structural changes [syndesmophytes/vertebral fusion, erosion, and fatty marrow deposition (FMD)]. The interobserver agreement was analysed based on 37 examinations. Radiographs were assessed for the presence of shiny corners, vertebral squaring, syndesmophytes/fusion, and erosion. Results: The interobserver agreement for the assessed MRI abnormalities was acceptable, with kappa values between 0.62 and 0.77. A total of 56 patients had SpA-related spinal abnormalities as depicted using MRI. The total chronic MRI score was not significantly related to the radiographic score, mainly because syndesmophytes were difficult to detect by MRI and FMD was only visualized by MRI. However, FMD was significantly related to the total radiographic score and vertebral squaring. Conclusion: The described MRI grading method was reliable for assessing both disease activity and chronic changes. MRI is promising for estimating chronic changes, but cervical radiography may still be needed. FMD seems to be an important sign of chronicity.

  3. An update on risk factors for cartilage loss in knee osteoarthritis assessed using MRI-based semiquantitative grading methods

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    Alizai, Hamza [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Aspetar Orthopaedic and Sports Medicine Hospital, Doha (Qatar); University of Texas Health Science Center at San Antonio, Department of Radiology, San Antonio, TX (United States); Roemer, Frank W. [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Aspetar Orthopaedic and Sports Medicine Hospital, Doha (Qatar); University of Erlangen-Nuremberg, Department of Radiology, Erlangen (Germany); Hayashi, Daichi [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Aspetar Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Yale University School of Medicine, Department of Radiology, Bridgeport Hospital, Bridgeport, CT (United States); Crema, Michel D. [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Aspetar Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Hospital do Coracao and Teleimagem, Department of Radiology, Sao Paulo (Brazil); Felson, David T. [Boston University School of Medicine, Clinical Epidemiology Research and Training Unit, Boston, MA (United States); Guermazi, Ali [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Aspetar Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Boston Medical Center, Boston, MA (United States)

    2014-11-07

    Arthroscopy-based semiquantitative scoring systems such as Outerbridge and Noyes' scores were the first to be developed for the purpose of grading cartilage defects. As magnetic resonance imaging (MRI) became available faor evaluation of the osteoarthritic knee joint, these systems were adapted for use with MRI. Later on, grading methods such as the Whole Organ Magnetic Resonance Score, the Boston-Leeds Osteoarthritis Knee Score and the MRI Osteoarthritis Knee Score were designed specifically for performing whole-organ assessment of the knee joint structures, including cartilage. Cartilage grades on MRI obtained with these scoring systems represent optimal outcome measures for longitudinal studies, and are designed to enhance understanding of the knee osteoarthritis disease process. The purpose of this narrative review is to describe cartilage assessment in knee osteoarthritis using currently available MRI-based semiquantitative whole-organ scoring systems, and to provide an update on the risk factors for cartilage loss in knee osteoarthritis as assessed with these scoring systems. (orig.)

  4. An update on risk factors for cartilage loss in knee osteoarthritis assessed using MRI-based semiquantitative grading methods

    International Nuclear Information System (INIS)

    Alizai, Hamza; Roemer, Frank W.; Hayashi, Daichi; Crema, Michel D.; Felson, David T.; Guermazi, Ali

    2015-01-01

    Arthroscopy-based semiquantitative scoring systems such as Outerbridge and Noyes' scores were the first to be developed for the purpose of grading cartilage defects. As magnetic resonance imaging (MRI) became available faor evaluation of the osteoarthritic knee joint, these systems were adapted for use with MRI. Later on, grading methods such as the Whole Organ Magnetic Resonance Score, the Boston-Leeds Osteoarthritis Knee Score and the MRI Osteoarthritis Knee Score were designed specifically for performing whole-organ assessment of the knee joint structures, including cartilage. Cartilage grades on MRI obtained with these scoring systems represent optimal outcome measures for longitudinal studies, and are designed to enhance understanding of the knee osteoarthritis disease process. The purpose of this narrative review is to describe cartilage assessment in knee osteoarthritis using currently available MRI-based semiquantitative whole-organ scoring systems, and to provide an update on the risk factors for cartilage loss in knee osteoarthritis as assessed with these scoring systems. (orig.)

  5. A new MRI grading system for chondromalacia patellae.

    Science.gov (United States)

    Özgen, Ali; Taşdelen, Neslihan; Fırat, Zeynep

    2017-04-01

    Background Chondromalacia patellae is a very common disorder. Although magnetic resonance imaging (MRI) is widely used to investigate patellar cartilage lesions, there is no descriptive MRI-based grading system for chondromalacia patellae. Purpose To propose a new MRI grading system for chondromalacia patellae with corresponding high resolution images which might be useful in precisely reporting and comparing knee examinations in routine daily practice and used in predicting natural course and clinical outcome of the patellar cartilage lesions. Material and Methods High resolution fat-saturated proton density (FS PD) images in the axial plane with corresponding T2 mapping images were reviewed. A detailed MRI grading system covering the deficiencies of the existing gradings has been set and presented on these images. Two experienced observers blinded to clinical data examined 44 knee MR images and evaluated patellar cartilage changes according to the proposed grading system. Inter- and intra-rater validity testing using kappa statistics were calculated. Results A descriptive and detailed grading system with corresponding FS PD and T2 mapping images has been presented. Inter-rater agreement was 0.80 (95% confidence interval [CI], 0.71-0.89). Intra-rater agreements were 0.83 (95% CI, 0.74-0.91) for observer A and 0.79 (95% CI, 0.70-0.88) for observer B (k-values). Conclusion We present a new MRI grading system for chondromalacia patellae with corresponding images and good inter- and intra-rater agreement which might be useful in reporting and comparing knee MRI examinations in daily practice and may also have the potential for using more precisely predicting prognosis and clinical outcome of the patients.

  6. Grading sacroiliitis with emphasis on MRI imaging; Grading der Sakroiliitis mit Betonung der MRT-Bildgebung

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    Jurik, A.G.; Egund, N. [The Department of Radiology R, Aarhus Kommunehospital (Denmark)

    2004-03-01

    Cross-sectional imaging techniques play a decisive role in identification, localization, and characterization of alterations in the sacroiliac joint during the early stage of seronegative spondylarthropathy (SpA). Although several studies showed that the diagnostic capabilities of MRI and CT are superior to those of conventional radiography, they have not yet become established and accepted as methods for evaluating the grade of ankylosing spondylitis (AS) in contrast to conventional radiography. The lack of acceptance for MRI and/or CT methods for evaluating and grading changes in the sacroiliac joint makes it difficult to include the results of these procedures in classifying the grade of SpA. Moreover, grading the changes in the sacroiliac joint in SpA with a method more sensitive than conventional radiography will be of prime importance in assessing treatment, e.g., the efficacy of new biological therapeutic agents directed against the tumor necrosis factor-alpha (TNF-{alpha}). An overview of the available grading methods is provided and MRI and CT techniques are presented. (orig.) [German] Schnittbildverfahren spielen bei der Identifizierung, Lokalisation und Charakterisierung von Veraenderungen des Sakroiliakalgelenks (SIG) im Fruehstadium der seronegativen Spondylarthropathie (SpA) eine entscheidende Rolle. Obwohl mehrere Studien zeigten, dass der diagnostische Wert der MRT und CT jenem der konventionellen Radiographie ueberlegen ist, hat sich das Schnittbildverfahren als Mittel zur Evaluierung des Grades der ankylosierenden Spondylitis (AS) im Gegensatz zur konventionellen Radiographie noch nicht etabliert und durchgesetzt. Dieses Fehlen eines akzeptierten MRT- und/oder CT-Verfahrens zur Evaluierung und zum Grading der Veraenderungen am SIG macht es schwierig, die Ergebnisse dieser Verfahren bei der Einstufung des Grades der AS-Veraenderungen und Erarbeitung von Diagnosekriterien fuer andere Formen der SpA einzubeziehen. Ausserdem wird das Grading der SIG

  7. Novel Diffusion-Weighted MRI for High-Grade Prostate Cancer Detection

    Science.gov (United States)

    2017-10-01

    technical difficulty with comparison of radical prostatectomy histology with imaging, we have also introduced a method to evaluate the accuracy of our...MatLab code for co-registration of digital radical prostatectomy histology to T2 weighted MRI images of alpha and DDC maps to T2 weighted MRI was...HPA 479 ( Evaluation of Clinical Interventions), with a grade of A. He completed BHIS 509 (Informatics for the Clinical Investigator) with a grade

  8. MRI differentiation of low-grade from high-grade appendicular chondrosarcoma

    International Nuclear Information System (INIS)

    Douis, Hassan; Singh, Leanne; Saifuddin, Asif

    2014-01-01

    To identify magnetic resonance imaging (MRI) features which differentiate low-grade chondral lesions (atypical cartilaginous tumours/grade 1 chondrosarcoma) from high-grade chondrosarcomas (grade 2, grade 3 and dedifferentiated chondrosarcoma) of the major long bones. We identified all patients treated for central atypical cartilaginous tumours and central chondrosarcoma of major long bones (humerus, femur, tibia) over a 13-year period. The MRI studies were assessed for the following features: bone marrow oedema, soft tissue oedema, bone expansion, cortical thickening, cortical destruction, active periostitis, soft tissue mass and tumour length. The MRI-features were compared with the histopathological tumour grading using univariate, multivariate logistic regression and receiver operating characteristic curve (ROC) analyses. One hundred and seventy-nine tumours were included in this retrospective study. There were 28 atypical cartilaginous tumours, 79 grade 1 chondrosarcomas, 36 grade 2 chondrosarcomas, 13 grade 3 chondrosarcomas and 23 dedifferentiated chondrosarcomas. Multivariate analysis demonstrated that bone expansion (P = 0.001), active periostitis (P = 0.001), soft tissue mass (P < 0.001) and tumour length (P < 0.001) were statistically significant differentiating factors between low-grade and high-grade chondral lesions with an area under the ROC curve of 0.956. On MRI, bone expansion, active periostitis, soft tissue mass and tumour length can reliably differentiate high-grade chondrosarcomas from low-grade chondral lesions of the major long bones. (orig.)

  9. MRI differentiation of low-grade from high-grade appendicular chondrosarcoma

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    Douis, Hassan; Singh, Leanne; Saifuddin, Asif [The Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom)

    2014-01-15

    To identify magnetic resonance imaging (MRI) features which differentiate low-grade chondral lesions (atypical cartilaginous tumours/grade 1 chondrosarcoma) from high-grade chondrosarcomas (grade 2, grade 3 and dedifferentiated chondrosarcoma) of the major long bones. We identified all patients treated for central atypical cartilaginous tumours and central chondrosarcoma of major long bones (humerus, femur, tibia) over a 13-year period. The MRI studies were assessed for the following features: bone marrow oedema, soft tissue oedema, bone expansion, cortical thickening, cortical destruction, active periostitis, soft tissue mass and tumour length. The MRI-features were compared with the histopathological tumour grading using univariate, multivariate logistic regression and receiver operating characteristic curve (ROC) analyses. One hundred and seventy-nine tumours were included in this retrospective study. There were 28 atypical cartilaginous tumours, 79 grade 1 chondrosarcomas, 36 grade 2 chondrosarcomas, 13 grade 3 chondrosarcomas and 23 dedifferentiated chondrosarcomas. Multivariate analysis demonstrated that bone expansion (P = 0.001), active periostitis (P = 0.001), soft tissue mass (P < 0.001) and tumour length (P < 0.001) were statistically significant differentiating factors between low-grade and high-grade chondral lesions with an area under the ROC curve of 0.956. On MRI, bone expansion, active periostitis, soft tissue mass and tumour length can reliably differentiate high-grade chondrosarcomas from low-grade chondral lesions of the major long bones. (orig.)

  10. Grading of cerebral gilomas: correlation with perfusion MRI, spectroscopic MRI and histopathology

    International Nuclear Information System (INIS)

    Law, M.; Cha, S.; Knopp, E.A.; Johnson, G.; Litt, A.W.

    2002-01-01

    Full text: The aim of this study was to determine the correlation between perfusion MRI (pMRI), spectroscopic MRI (sMRI) and histopathologic grading of primary glial neoplasms. Echo-planar pMRI has already been shown to be a robust physiological tool in preoperatively predicting tumor grade and guiding stereotactic biopsy (1). Thirty-four patients with a primary glial neoplasm underwent conventional MR imaging, T2*-weighted echo planar pMRI and sMRI. Four rCBV measurements were obtained from the colour maps of each lesion to determine the maximum rCBV. Spectroscopic MRI utilizing 2D chemical shift imaging at a TE of 135 provided multi-voxel spectroscopic data in sixteen of these patients. The maximum Cho/NAA, Cho/Cr, and minimum NAA/Cr ratios were obtained as well as documenting the presence of lactate and lipids. This was compared with the histopathological grading (including staining with H and E, GFAP, vimentin and MIB1, proliferative index) obtained from volumetric resection or stereotactic biopsy. The maximum rCBV in high grade tumors (n=26) ranged from 1.34 to 5.15, with a mean of 3.00 ± 1.21 (SD), and in the low grade tumors (n=8) ranged from 1.47 to 2.49, with a mean of 1.81 ± 1.21 (SD).This difference was statistically significant (p<0.001; Student t test). Maximum values for Cho/NAA, Cho/Cr and minimum NAA/Cr values were 3.24 ± 3.26, 2.49 ± 1.17 and 1.02 ± 0.34, respectively in the high grade (n = 11), and 1.3 ± 0.39, 1.58 ± 0.45 and 0.89 ± 0.37 respectively in the low-grade tumors (n = 5). A statistically significant difference was found for the Cho/Cr ratio (p<0.05) between the high grade and low grade groups. Relative CBV measurements and spectroscopic metabolic ratios are complementary and correlate with histopathology (2,3). These tools provide powerful physiological and metabolic information for preoperative prediction of tumor grade and will guide pre and post operative planning and management. Copyright (2002) Blackwell Science Pty Ltd

  11. Visual MRI grading system to evaluate atrophy of the supeaspinatus muscle

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    Lim, Hyun Kyoung; Hong, Sung Hwan; Yoo, Hye Jin; Choi, Ja Young; Kim, Sae Hoon; Choi, Jung Ah; Kang, Heung Sik [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-08-15

    To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI). Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear. The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026). The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.

  12. Visual MRI grading system to evaluate atrophy of the supeaspinatus muscle

    International Nuclear Information System (INIS)

    Lim, Hyun Kyoung; Hong, Sung Hwan; Yoo, Hye Jin; Choi, Ja Young; Kim, Sae Hoon; Choi, Jung Ah; Kang, Heung Sik

    2014-01-01

    To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI). Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear. The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026). The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.

  13. Pharmacokinetic MRI of the prostate. Parameters for differentiating low-grade and high-grade prostate cancer

    International Nuclear Information System (INIS)

    Franiel, T.; Taupitz, M.; Asbach, P.; Beyersdorff, D.; Luedemann, L.; Rost, J.

    2009-01-01

    Purpose: to investigate whether pharmacokinetic MRI parameters ''perfusion, blood volume, mean transit time (MTT), interstitial volume, permeability, extraction coefficient, delay, and dispersion'' allow the differentiation of low-grade (Gleason score ≤ 6) and high-grade (Gleason score ≥ 7) prostate cancer. Materials and method: forty-two patients with prostate cancer verified by biopsy (PSA 2.7 to 31.4ng/ml) and scheduled for prostatectomy underwent MRI at 1.5 Tesla using the dynamic contrast-enhanced inversion-prepared dual-contrast gradient echo sequence (temporal resolution, 1.65 s) and a combined endorectal body phased array coil. Parametric maps were computed using a sequential 3-compartment model and the corresponding post-processing algorithms. A total of 41 areas of prostate cancer (15 low-grade, 26 high-grade cancers) in 32 patients were able to be correlated with the prostatectomy specimens and were included in the analysis. Results: low-grade prostate cancers had a higher mean blood volume (1.76% vs. 1.64%, p = 0.039), longer MTT (6.39 s vs. 3.25 s, p -1 vs. 3.86 min -1 , p = 0.011) than high-grade cancers. No statistically significant difference was found for perfusion (p = 0.069), interstitial volume (p = 0.849), extraction coefficient (p = 0.615), delay (p = 0.489), and dispersion (p = 0.306). (orig.)

  14. Intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injuries

    International Nuclear Information System (INIS)

    Wangensteen, Arnlaug; Tol, Johannes L.; Roemer, Frank W.; Bahr, Roald; Dijkstra, H. Paul; Crema, Michel D.; Farooq, Abdulaziz; Guermazi, Ali

    2017-01-01

    Highlights: • Three different MRI grading and classification systems for acute hamstring injuries are overall reliable. • Reliability for the subcategories within these MRI grading and classification systems remains, however, unclear. - Abstract: Objective: To assess and compare the intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injury. Methods: Male athletes (n = 40) with clinical diagnosis of acute hamstring injury and MRI ≤5 days were selected from a prospective cohort. Two radiologists independently evaluated the MRIs using standardised scoring form including the modified Peetrons grading system, the Chan acute muscle strain injury classification and the British Athletics Muscle Injury Classification. Intra-and interrater reliability was assessed with linear weighted kappa (κ) or unweighted Cohen's κ and percentage agreement was calculated. Results: We observed ‘substantial’ to ‘almost perfect’ intra- (κ range 0.65–1.00) and interrater reliability (κ range 0.77–1.00) with percentage agreement 83–100% and 88–100%, respectively, for severity gradings, overall anatomical sites and overall classifications for the three MRI systems. We observed substantial variability (κ range −0.05 to 1.00) for subcategories within the Chan classification and the British Athletics Muscle Injury Classification, however, the prevalence of positive scorings was low for some subcategories. Conclusions: The modified Peetrons grading system, overall Chan classification and overall British Athletics Muscle Injury Classification demonstrated ‘substantial' to ‘almost perfect' intra- and interrater reliability when scored by experienced radiologists. The intra- and interrater reliability for the anatomical subcategories within the classifications remains unclear.

  15. Intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injuries

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    Wangensteen, Arnlaug, E-mail: arnlaug.wangensteen@nih.no [Aspetar, Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo (Norway); Tol, Johannes L., E-mail: johannes.tol@aspetar.com [Aspetar, Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Amsterdam Center for Evidence Sports Medicine, Academic Medical Center (Netherlands); The Sports Physician Group, OLVG, Amsterdam (Netherlands); Roemer, Frank W. [Quantitative Imaging Center, Department of Radiology, Boston University School of Medicine, Boston, MA (United States); Department of Radiology, University of Erlangen-Nuremberg, Erlangen (Germany); Bahr, Roald [Aspetar, Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo (Norway); Dijkstra, H. Paul [Aspetar, Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Crema, Michel D. [Quantitative Imaging Center, Department of Radiology, Boston University School of Medicine, Boston, MA (United States); Department of Radiology, Saint-Antoine Hospital, University Paris VI, Paris (France); Farooq, Abdulaziz [Aspetar, Orthopaedic and Sports Medicine Hospital, Doha (Qatar); Guermazi, Ali [Quantitative Imaging Center, Department of Radiology, Boston University School of Medicine, Boston, MA (United States)

    2017-04-15

    Highlights: • Three different MRI grading and classification systems for acute hamstring injuries are overall reliable. • Reliability for the subcategories within these MRI grading and classification systems remains, however, unclear. - Abstract: Objective: To assess and compare the intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injury. Methods: Male athletes (n = 40) with clinical diagnosis of acute hamstring injury and MRI ≤5 days were selected from a prospective cohort. Two radiologists independently evaluated the MRIs using standardised scoring form including the modified Peetrons grading system, the Chan acute muscle strain injury classification and the British Athletics Muscle Injury Classification. Intra-and interrater reliability was assessed with linear weighted kappa (κ) or unweighted Cohen's κ and percentage agreement was calculated. Results: We observed ‘substantial’ to ‘almost perfect’ intra- (κ range 0.65–1.00) and interrater reliability (κ range 0.77–1.00) with percentage agreement 83–100% and 88–100%, respectively, for severity gradings, overall anatomical sites and overall classifications for the three MRI systems. We observed substantial variability (κ range −0.05 to 1.00) for subcategories within the Chan classification and the British Athletics Muscle Injury Classification, however, the prevalence of positive scorings was low for some subcategories. Conclusions: The modified Peetrons grading system, overall Chan classification and overall British Athletics Muscle Injury Classification demonstrated ‘substantial' to ‘almost perfect' intra- and interrater reliability when scored by experienced radiologists. The intra- and interrater reliability for the anatomical subcategories within the classifications remains unclear.

  16. Liver iron estimation in β-thalassaemia: Comparison of MRI biochemical assay and histological grading

    International Nuclear Information System (INIS)

    Chan, Y.L.; Li, C.K.; Lam, C.W.K.; Yu, S.C.H.; Chik, K.W.; To, K.F.; Yeung, D.K.W.; Howard, R.; Yuen, P.M.P.

    2001-01-01

    AIMS: The aims of the study were to compare the efficacy of magnetic resonance imaging (MRI), biochemical assay and histological grading in estimating liver iron content, and to evaluate the value of liver to muscle signal intensity ratio (L/M ratio) on spin-echo T1-weighted images in this role. MATERIALS AND METHODS: Thirty-nine homozygous β -thalassaemics had their L/M ratio measured on MRI, followed by ultrasound-guided liver biopsies with histological grading of iron storage and biochemical quantification of liver iron concentration (LIC-b) using atomic absorption spectrophotometry. RESULTS: A significant difference in L/M ratios between the four grades of iron storage on histology was observed (P 15 mg/g. A L/M ratio of > 0.8 predicts a histological iron storage grading of 0 or 1 with a 100% sensitivity and 74% specificity. CONCLUSION: L/M ratio on MRI is of value as a non-invasive alternative to repeated liver biopsies for estimating liver iron content at clinically important thresholds. Chan, Y.L. et al. (2001)

  17. Gliomas: Application of Cumulative Histogram Analysis of Normalized Cerebral Blood Volume on 3 T MRI to Tumor Grading

    Science.gov (United States)

    Kim, Hyungjin; Choi, Seung Hong; Kim, Ji-Hoon; Ryoo, Inseon; Kim, Soo Chin; Yeom, Jeong A.; Shin, Hwaseon; Jung, Seung Chai; Lee, A. Leum; Yun, Tae Jin; Park, Chul-Kee; Sohn, Chul-Ho; Park, Sung-Hye

    2013-01-01

    Background Glioma grading assumes significant importance in that low- and high-grade gliomas display different prognoses and are treated with dissimilar therapeutic strategies. The objective of our study was to retrospectively assess the usefulness of a cumulative normalized cerebral blood volume (nCBV) histogram for glioma grading based on 3 T MRI. Methods From February 2010 to April 2012, 63 patients with astrocytic tumors underwent 3 T MRI with dynamic susceptibility contrast perfusion-weighted imaging. Regions of interest containing the entire tumor volume were drawn on every section of the co-registered relative CBV (rCBV) maps and T2-weighted images. The percentile values from the cumulative nCBV histograms and the other histogram parameters were correlated with tumor grades. Cochran’s Q test and the McNemar test were used to compare the diagnostic accuracies of the histogram parameters after the receiver operating characteristic curve analysis. Using the parameter offering the highest diagnostic accuracy, a validation process was performed with an independent test set of nine patients. Results The 99th percentile of the cumulative nCBV histogram (nCBV C99), mean and peak height differed significantly between low- and high-grade gliomas (P = histogram analysis of nCBV using 3 T MRI can be a useful method for preoperative glioma grading. The nCBV C99 value is helpful in distinguishing high- from low-grade gliomas and grade IV from III gliomas. PMID:23704910

  18. What are the differentiating clinical and MRI-features of enchondromas from low-grade chondrosarcomas?

    Energy Technology Data Exchange (ETDEWEB)

    Douis, Hassan [Royal Orthopaedic Hospital, Department of Radiology, Birmingham (United Kingdom); University Hospital Birmingham, Department of Radiology, Birmingham (United Kingdom); Parry, M. [Royal Orthopaedic Hospital, Department of Orthopaedic Oncology, Birmingham (United Kingdom); Vaiyapuri, S. [Royal Orthopaedic Hospital, Department of Musculoskeletal Pathology, Birmingham (United Kingdom); Davies, A.M. [Royal Orthopaedic Hospital, Department of Radiology, Birmingham (United Kingdom)

    2018-01-15

    To evaluate the role of clinical assessment, conventional and dynamic contrast-enhanced MRI in differentiating enchondromas from chondrosarcomas of long bone. The following clinical and MRI findings were assessed: age, gender, pain, pain attributable to lesion, tumour location, tumour length, presence, depth of endosteal scalloping, bone marrow oedema, soft tissue oedema, cortical destruction, periosteal reaction, bone expansion, macroscopic fat, calcification, soft tissue mass, haemorrhage, dynamic contrast-enhanced MRI. Clinical and MRI findings were compared with histopathological grading. Sixty patients with central chondroid tumours were included (27 enchondromas, 10 cartilaginous lesions of unknown malignant potential, 15 grade 1 chondrosarcomas, 8 high-grade chondrosarcomas). Pain attributed to lesion, tumour length, endosteal scalloping > 2/3, cortical destruction, bone expansion and soft tissue mass were differentiating features between enchondromas and grade 1 chondrosarcomas. Dynamic contrast-enhanced MRI could not differentiate enchondromas from grade 1 chondrosarcomas. Previously reported imaging signs of chondrosarcomas are useful in the diagnosis of grade 1 lesions but have lower sensitivity than in higher grade lesions. Deep endosteal scalloping is the most sensitive imaging sign of grade 1 chondrosarcomas. Pain due to the lesion is an important clinical sign of grade 1 chondrosarcomas. Dynamic contrast-enhanced MRI is not useful in differentiating enchondromas from grade 1 chondrosarcomas. (orig.)

  19. 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.)

  20. A practical MRI grading system for osteoarthritis of the knee: Association with Kellgren–Lawrence radiographic scores

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hee-Jin, E-mail: parkhiji@gmail.com [Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, #108 Pyung-dong, Jongno-gu, Seoul 110-746 (Korea, Republic of); Department of Radiology, Kangwon National University School of Medicine, Baengnyeong-ro 156, Chuncheon-Si, Gangwon-Do Kangwon National University Hospital 200-722 (Korea, Republic of); Kim, Sam Soo, E-mail: samskim@kangwon.ac.kr [Department of Radiology, Kangwon National University School of Medicine, Baengnyeong-ro 156, Chuncheon-Si, Gangwon-Do Kangwon National University Hospital 200-722 (Korea, Republic of); Lee, So-Yeon, E-mail: parkhiji@kwandong.ac.kr [Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, #108 Pyung-dong, Jongno-gu, Seoul 110-746 (Korea, Republic of); Park, Noh-Hyuck, E-mail: nhpark904@kwandong.ac.kr [Department of Radiology, Myongji Hospital, Kwandong University, College of Medicine, 697-24 Hwajung-dong, Dukyang-ku, Koyang, Kyunggi 412-270 (Korea, Republic of); Park, Ji-Yeon, E-mail: zzzz3@hanmail.net [Department of Radiology, Myongji Hospital, Kwandong University, College of Medicine, 697-24 Hwajung-dong, Dukyang-ku, Koyang, Kyunggi 412-270 (Korea, Republic of); Choi, Yoon-Jung, E-mail: yoonchoi99@gmail.com [Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, #108 Pyung-dong, Jongno-gu, Seoul 110-746 (Korea, Republic of); Jeon, Hyun-Jun, E-mail: ostrich-13@hanmail.net [Department of Occupational Medicine, Dongsan Medical Center, Keimyung University School of Medicine, 194 Dongsan-Dong, Jung-ku, Taegu (Korea, Republic of)

    2013-01-15

    Purpose: To propose a reproducible and constant MR grading system for osteoarthritis of the knee joint that provides high interobserver and intraoberver agreement and that does not require complicated calculation procedures. Materials and methods: This retrospective study sample included 44 men and 65 women who underwent both MRI and plain radiography of the knee at our institution. All patients were older than 50 years of age (mean 57.7) and had clinically suspected osteoarthritis of the knee. The standard of 4 grades on the MR grade scale was based mainly on cartilage injury and additional findings. Kellgren–Lawrence grades were assessed for the same patient group. The relationship between the results was determined. Statistical analyses were performed including kappa statistics, categorical regression analysis and nonparametric correlation analysis. Results: The interobserver and intraoberver agreements between the two readers in the grading of osteoarthritis were found to be almost perfect. Interobserver and intraobserver agreements were slightly lower for the MR grading system than for the Kellgren–Lawrence grading scale. The correlation between the MR grade and Kellgren–Lawrence grade was very high and did not differ with patient age. The MR grades were highly correlated with the Kellgren–Lawrence grades and showed excellent interobserver and intraobserver agreements. Conclusion: This new MR grading system for osteoarthritis of the knee joint is reproducible and may be helpful for the grading of osteoarthritis of the knee without requiring reference to plain radiography.

  1. A practical MRI grading system for osteoarthritis of the knee: Association with Kellgren–Lawrence radiographic scores

    International Nuclear Information System (INIS)

    Park, Hee-Jin; Kim, Sam Soo; Lee, So-Yeon; Park, Noh-Hyuck; Park, Ji-Yeon; Choi, Yoon-Jung; Jeon, Hyun-Jun

    2013-01-01

    Purpose: To propose a reproducible and constant MR grading system for osteoarthritis of the knee joint that provides high interobserver and intraoberver agreement and that does not require complicated calculation procedures. Materials and methods: This retrospective study sample included 44 men and 65 women who underwent both MRI and plain radiography of the knee at our institution. All patients were older than 50 years of age (mean 57.7) and had clinically suspected osteoarthritis of the knee. The standard of 4 grades on the MR grade scale was based mainly on cartilage injury and additional findings. Kellgren–Lawrence grades were assessed for the same patient group. The relationship between the results was determined. Statistical analyses were performed including kappa statistics, categorical regression analysis and nonparametric correlation analysis. Results: The interobserver and intraoberver agreements between the two readers in the grading of osteoarthritis were found to be almost perfect. Interobserver and intraobserver agreements were slightly lower for the MR grading system than for the Kellgren–Lawrence grading scale. The correlation between the MR grade and Kellgren–Lawrence grade was very high and did not differ with patient age. The MR grades were highly correlated with the Kellgren–Lawrence grades and showed excellent interobserver and intraobserver agreements. Conclusion: This new MR grading system for osteoarthritis of the knee joint is reproducible and may be helpful for the grading of osteoarthritis of the knee without requiring reference to plain radiography

  2. Differentiation between grade 3 and grade 4 articular cartilage defects of the knee: Fat-suppressed proton density-weighted versus fat-suppressed three-dimensional gradient-echo MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Yeon; Jee, Won-Hee; Kim, Sun Ki (Dept. of Radiology, Seoul St Mary' s Hospital, Catholic Univ. of Korea, Seoul (Korea)), e-mail: whjee@catholic.ac.kr; Koh, In-Jun (Dept. of Joint Reconstruction Center, Seoul National Univ. Bundang Hospital, Seoul (Korea)); Kim, Jung-Man (Dept. of Orthopedic Surgery, Seoul St Mary' s Hospital, Catholic Univ. of Korea, Seoul (Korea))

    2010-05-15

    Background: Fat-suppressed (FS) proton density (PD)-weighted magnetic resonance imaging (MRI) and FS three-dimensional (3D) gradient-echo imaging such as spoiled gradient-recalled (SPGR) sequence have been established as accurate methods for detecting articular cartilage defects. Purpose: To retrospectively compare the diagnostic efficacy between FS PD-weighted and FS 3D gradient-echo MRI for differentiating between grade 3 and grade 4 cartilage defects of the knee with arthroscopy as the standard of reference. Material and Methods: Twenty-one patients who had grade 3 or 4 cartilage defects in medial femoral condyle at arthroscopy and knee MRI were included in this study: grade 3, >50% cartilage defects; grade 4, full thickness cartilage defects exposed to the bone. Sagittal FS PD-weighted MR images and FS 3D gradient-echo images with 1.5 T MR images were independently graded for the cartilage abnormalities of medial femoral condyle by two musculoskeletal radiologists. Statistical analysis was performed by Fisher's exact test. Inter-observer agreement in grading of cartilage was assessed using ? coefficients. Results: Arthroscopy revealed grade 3 defects in 17 patients and grade 4 defects in 4 patients in medial femoral condyles. For FS 3D gradient-echo images grade 3 defects were graded as grade 3 (n=15) and grade 4 (n=2), and all grade 4 defects (n=4) were correctly graded. However, for FS PD-weighted MR images all grade 3 defects were misinterpreted as grade 1 (n=1) and grade 4 (n=16), whereas all grade 4 defects (n=4) were correctly graded. FS 3D gradient-echo MRI could differentiate grade 3 from grade 4 defects (P=0.003), whereas FS PD-weighted imaging could not (P=1.0). Inter-observer agreement was substantial (?=0.70) for grading of cartilage using FS PD-weighted imaging, whereas it was moderate (?=0.46) using FS 3D gradient-echo imaging. Conclusion: FS 3D gradient-echo MRI is more helpful for differentiating between grade 3 and grade 4 cartilage

  3. MRI Brain Tumor Segmentation Methods- A Review

    OpenAIRE

    Gursangeet, Kaur; Jyoti, Rani

    2016-01-01

    Medical image processing and its segmentation is an active and interesting area for researchers. It has reached at the tremendous place in diagnosing tumors after the discovery of CT and MRI. MRI is an useful tool to detect the brain tumor and segmentation is performed to carry out the useful portion from an image. The purpose of this paper is to provide an overview of different image segmentation methods like watershed algorithm, morphological operations, neutrosophic sets, thresholding, K-...

  4. Optimizing a machine learning based glioma grading system using multi-parametric MRI histogram and texture features.

    Science.gov (United States)

    Zhang, Xin; Yan, Lin-Feng; Hu, Yu-Chuan; Li, Gang; Yang, Yang; Han, Yu; Sun, Ying-Zhi; Liu, Zhi-Cheng; Tian, Qiang; Han, Zi-Yang; Liu, Le-De; Hu, Bin-Quan; Qiu, Zi-Yu; Wang, Wen; Cui, Guang-Bin

    2017-07-18

    Current machine learning techniques provide the opportunity to develop noninvasive and automated glioma grading tools, by utilizing quantitative parameters derived from multi-modal magnetic resonance imaging (MRI) data. However, the efficacies of different machine learning methods in glioma grading have not been investigated.A comprehensive comparison of varied machine learning methods in differentiating low-grade gliomas (LGGs) and high-grade gliomas (HGGs) as well as WHO grade II, III and IV gliomas based on multi-parametric MRI images was proposed in the current study. The parametric histogram and image texture attributes of 120 glioma patients were extracted from the perfusion, diffusion and permeability parametric maps of preoperative MRI. Then, 25 commonly used machine learning classifiers combined with 8 independent attribute selection methods were applied and evaluated using leave-one-out cross validation (LOOCV) strategy. Besides, the influences of parameter selection on the classifying performances were investigated. We found that support vector machine (SVM) exhibited superior performance to other classifiers. By combining all tumor attributes with synthetic minority over-sampling technique (SMOTE), the highest classifying accuracy of 0.945 or 0.961 for LGG and HGG or grade II, III and IV gliomas was achieved. Application of Recursive Feature Elimination (RFE) attribute selection strategy further improved the classifying accuracies. Besides, the performances of LibSVM, SMO, IBk classifiers were influenced by some key parameters such as kernel type, c, gama, K, etc. SVM is a promising tool in developing automated preoperative glioma grading system, especially when being combined with RFE strategy. Model parameters should be considered in glioma grading model optimization.

  5. Diagnostic Values of DCE-MRI and DSC-MRI for Differentiation Between High-grade and Low-grade Gliomas: A Comprehensive Meta-analysis.

    Science.gov (United States)

    Liang, Jianye; Liu, Dexiang; Gao, Peng; Zhang, Dong; Chen, Hanwei; Shi, Changzheng; Luo, Liangping

    2018-03-01

    This study aimed to collect the studies on the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and dynamic susceptibility contrast MRI (DSC-MRI) in differentiating the grades of gliomas, and evaluate the diagnostic performances of relevant quantitative parameters in glioma grading. We systematically searched studies on the diagnosis of gliomas with DCE-MRI or DSC-MRI in Medline, PubMed, China National Knowledge Infrastructure database, Cochrane Library, and Embase published between January 2005 and December 2016. Standardized mean differences and 95% confidence intervals were calculated for volume transfer coefficient (K trans ), volume fraction of extravascular extracellular space (V e ), rate constant of backflux (K ep ), relative cerebral blood volume (rCBV), and relative cerebral blood flow (rCBF) using Review Manager 5.2 software. Sensitivity, specificity, area under the curve (AUC), and Begg test were calculated by Stata 12.0. Twenty-two studies with available outcome data were included in the analysis. The standardized mean difference of K trans values between high-grade glioma and low-grade glioma were 1.18 (0.91, 1.45); V e values were 1.43 (1.06, 1.80); K ep values were 0.65 (-0.05, 1.36); rCBV values were 1.44 (1.08, 1.81); and rCBF values were 1.17 (0.68, 1.67), respectively. The results were all significant statistically (P values (P = .07), and high-grade glioma had higher K trans , V e , rCBV, and rCBF values than low-grade glioma. AUC values of K trans , V e , rCBV, and rCBF were 0.90, 0.88, 0.93, and 0.73, respectively; rCBV had the largest AUC among the four parameters (P < .05). Both DCE-MRI and DSC-MRI are reliable techniques in differentiating the grades of gliomas, and rCBV was found to be the most sensitive one. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  6. [18F]-fluoro-l-thymidine PET and advanced MRI for preoperative grading of gliomas

    Directory of Open Access Journals (Sweden)

    S. Collet

    2015-01-01

    Conclusion: Whereas advanced MRI parameters give indications for the grading of gliomas, the addition of [18F]-FLT-PET could be of interest for the accurate preoperative classification of diffuse gliomas, particularly for identification of doubtful grade III and IV gliomas.

  7. Emerging role of functional brain MRI in low-grade glioma surgery

    DEFF Research Database (Denmark)

    Friismose, Ancuta; Traise, Peter; Markovic, Ljubo

    Learning objectives 1. To describe the use of functional MRI (fMRI) in cranial surgery planning for patients with low-grade gliomas (LGG). 2. To show the increasing importance of fMRI in the clinical setting. Background LGG include brain tumors classified by the World Health Organization as grade I...... be used to map eloquent cortex areas, thus minimizing postoperative deficits and improving surgical performance. Findings and procedure details Patients diagnosed with low-grade gliomas located in eloquent brain areas undergo fMRI prior to surgery. The exams are performed on a 3T MR system (Achieva TX....... Language comprehension and visual tasks can be added to visualize Wernicke’s area or the visual cortex. Diffusion tensor imaging (DTI) is used to map nerve tract course relative to the tumour. Conclusion FMRI has proven its clinical utility in locating eloquent brain areas with relation to tumor site...

  8. Quantitative rotating frame relaxometry methods in MRI.

    Science.gov (United States)

    Gilani, Irtiza Ali; Sepponen, Raimo

    2016-06-01

    Macromolecular degeneration and biochemical changes in tissue can be quantified using rotating frame relaxometry in MRI. It has been shown in several studies that the rotating frame longitudinal relaxation rate constant (R1ρ ) and the rotating frame transverse relaxation rate constant (R2ρ ) are sensitive biomarkers of phenomena at the cellular level. In this comprehensive review, existing MRI methods for probing the biophysical mechanisms that affect the rotating frame relaxation rates of the tissue (i.e. R1ρ and R2ρ ) are presented. Long acquisition times and high radiofrequency (RF) energy deposition into tissue during the process of spin-locking in rotating frame relaxometry are the major barriers to the establishment of these relaxation contrasts at high magnetic fields. Therefore, clinical applications of R1ρ and R2ρ MRI using on- or off-resonance RF excitation methods remain challenging. Accordingly, this review describes the theoretical and experimental approaches to the design of hard RF pulse cluster- and adiabatic RF pulse-based excitation schemes for accurate and precise measurements of R1ρ and R2ρ . The merits and drawbacks of different MRI acquisition strategies for quantitative relaxation rate measurement in the rotating frame regime are reviewed. In addition, this review summarizes current clinical applications of rotating frame MRI sequences. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Impact of MRI on high grade Ductal Carcinoma Insitu (HG DCIS) management, are we using the full scope of MRI?

    Science.gov (United States)

    Hajaj, Mohamad; Karim, Ahmed; Pascaline, Sana; Noor, Lubna; Patel, Shivali; Dakka, Mahmoud

    2017-10-01

    Preoperative assessment of pure Ductal Carcinoma Insitu (DCIS) is essential in the surgical planning. The role of Magnetic resonance imaging (MRI) has long been debated. The impact of MRI on the management of High Grade (HG) DCIS was assessed, whether it accurately captures the true size of this entity in comparison to conventional imaging, and, if MRI use would reduce the number of re-excision surgery. Ninety-one consecutive patients with HG DCIS, who were identified from a prospectively collected data at Kettering General Hospital between April 2011 and December 2015. All patients had preoperative MRI scan in addition to the standard breast imaging. This was compared to a control group of consecutive patients (n=52) which was obtained from a period just before 2011. Impact on surgical planning and number of surgeries for each patient was compared. The size of HG DCIS estimated by MRI was compared to the final histological size. Secondary outcomes included change of initial surgical plan and detection of occult contralateral breast cancer. MRI group had 91 patients with median age of 63. Seventy percent of which presented through the screening program. The overall sensitivity of MRI to detect HG DCIS was 77% (70/91) with a false negative rate FNR of 23% (21/91). Therefore, 70 patients only were included in the data analysis. The control group included 52 screening patients with comparable baseline characteristics. Re-excision (or completion mastectomy) rates were higher in the control group 26% compared to 8% in the MRI group (P-value 0.012). MRI use correctly converted the initial plan of breast conservation to mastectomy in 9 patients (13%). Five patients had additional ipsilateral malignant features (7%).Occult contra lateral disease, was diagnosed in 2 patients (3%). This study suggests that MRI could be an important tool in reducing the re-excision rates in the surgical management of HG DCIS. Although still controversial, selective MRI imaging can be useful

  10. Diagnostic accuracy of automatic normalization of CBV in glioma grading using T1- weighted DCE-MRI.

    Science.gov (United States)

    Sahoo, Prativa; Gupta, Rakesh K; Gupta, Pradeep K; Awasthi, Ashish; Pandey, Chandra M; Gupta, Mudit; Patir, Rana; Vaishya, Sandeep; Ahlawat, Sunita; Saha, Indrajit

    2017-12-01

    Aim of this retrospective study was to compare diagnostic accuracy of proposed automatic normalization method to quantify the relative cerebral blood volume (rCBV) with existing contra-lateral region of interest (ROI) based CBV normalization method for glioma grading using T1-weighted dynamic contrast enhanced MRI (DCE-MRI). Sixty patients with histologically confirmed gliomas were included in this study retrospectively. CBV maps were generated using T1-weighted DCE-MRI and are normalized by contralateral ROI based method (rCBV_contra), unaffected white matter (rCBV_WM) and unaffected gray matter (rCBV_GM), the latter two of these were generated automatically. An expert radiologist with >10years of experience in DCE-MRI and a non-expert with one year experience were used independently to measure rCBVs. Cutoff values for glioma grading were decided from ROC analysis. Agreement of histology with rCBV_WM, rCBV_GM and rCBV_contra respectively was studied using Kappa statistics and intra-class correlation coefficient (ICC). The diagnostic accuracy of glioma grading using the measured rCBV_contra by expert radiologist was found to be high (sensitivity=1.00, specificity=0.96, pnormalization method showed same percentage of agreement for both expert and non-expert user. rCBV_WM showed an agreement of 88.33% (kappa=0.76,pnormalization of CBV using the proposed method could provide better diagnostic accuracy compared to the manual contralateral based approach. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Automatic MRI Quantifying Methods in Behavioral-Variant Frontotemporal Dementia Diagnosis

    DEFF Research Database (Denmark)

    Cajanus, Antti; Hall, Anette; Koikkalainen, Juha

    2018-01-01

    genetic status in the differentiation sensitivity. Methods: The MRI scans of 50 patients with bvFTD (17 C9ORF72 expansion carriers) were analyzed using 6 quantification methods as follows: voxel-based morphometry (VBM), tensor-based morphometry, volumetry (VOL), manifold learning, grading, and white...

  12. Detection and grading of dAVF: prospects and limitations of 3T MRI.

    Science.gov (United States)

    Bink, Andrea; Berkefeld, Joachim; Wagner, Marlies; You, Se-Jong; Ackermann, Hanns; Lorenz, Matthias W; Senft, Christian; du Mesnil de Rochemont, Richard

    2012-02-01

    DSA is currently the criterion standard for the assessment of dural arteriovenous fistulas (dAVF). Recently, evolving MRA techniques have emerged as a non-invasive alternative. The aim of this study is to assess the value of 3 T MRI in detecting and describing dAVF and to determine whether MRI can replace DSA as diagnostic procedure. A total of 19 patients with dAVF and 19 without dAVF underwent the same MRI protocol, including 3D time-of-flight MRA and time-resolved contrast-enhanced MRA. The images were evaluated retrospectively by three independent readers with different levels of experience blinded to clinical information. The readers assessed the presence, the site, the venous drainage and the feeders of dAVF. Sensitivity, specificity, accuracy, intertechnique and interobserver agreements were calculated. DAVF can be detected with high sensitivity, specificity and accuracy by experienced and also by less experienced readers. However, MRI has limitations when used for grading and evaluation of the angioarchitecture of the dAVF. Different experience, the limited resolution of MRI and its inability to selectively display arteries were the reasons for these limitations. With MRI dAVF can be detected reliably. Nevertheless, at present MRI can not fully replace DSA, especially for treatment planning.

  13. MRI features can predict EGFR expression in lower grade gliomas. A voxel-based radiomic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yiming; Liu, Xing; Qian, Zenghui; Fan, Xing; Li, Shaowu; Jiang, Tao [Capital Medical University, Beijing Neurosurgical Institute, Beijing (China); Xu, Kaibin [Chinese Academy of Sciences, Institute of Automation, Beijing (China); Wang, Kai [Beijing Tiantan Hospital, Department of Neuroradiology, Beijing (China); Wang, Yinyan [Beijing Tiantan Hospital, Department of Neuroradiology, Beijing (China); Beijing Tiantan Hospital, Capital Medical University, Department of Neurosurgery, Beijing (China)

    2018-01-15

    To identify the magnetic resonance imaging (MRI) features associated with epidermal growth factor (EGFR) expression level in lower grade gliomas using radiomic analysis. 270 lower grade glioma patients with known EGFR expression status were randomly assigned into training (n=200) and validation (n=70) sets, and were subjected to feature extraction. Using a logistic regression model, a signature of MRI features was identified to be predictive of the EGFR expression level in lower grade gliomas in the training set, and the accuracy of prediction was assessed in the validation set. A signature of 41 MRI features achieved accuracies of 82.5% (area under the curve [AUC] = 0.90) in the training set and 90.0% (AUC = 0.95) in the validation set. This radiomic signature consisted of 25 first-order statistics or related wavelet features (including range, standard deviation, uniformity, variance), one shape and size-based feature (spherical disproportion), and 15 textural features or related wavelet features (including sum variance, sum entropy, run percentage). A radiomic signature allowing for the prediction of the EGFR expression level in patients with lower grade glioma was identified, suggesting that using tumour-derived radiological features for predicting genomic information is feasible. (orig.)

  14. Intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injuries.

    Science.gov (United States)

    Wangensteen, Arnlaug; Tol, Johannes L; Roemer, Frank W; Bahr, Roald; Dijkstra, H Paul; Crema, Michel D; Farooq, Abdulaziz; Guermazi, Ali

    2017-04-01

    To assess and compare the intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injury. Male athletes (n=40) with clinical diagnosis of acute hamstring injury and MRI ≤5days were selected from a prospective cohort. Two radiologists independently evaluated the MRIs using standardised scoring form including the modified Peetrons grading system, the Chan acute muscle strain injury classification and the British Athletics Muscle Injury Classification. Intra-and interrater reliability was assessed with linear weighted kappa (κ) or unweighted Cohen's κ and percentage agreement was calculated. We observed 'substantial' to 'almost perfect' intra- (κ range 0.65-1.00) and interrater reliability (κ range 0.77-1.00) with percentage agreement 83-100% and 88-100%, respectively, for severity gradings, overall anatomical sites and overall classifications for the three MRI systems. We observed substantial variability (κ range -0.05 to 1.00) for subcategories within the Chan classification and the British Athletics Muscle Injury Classification, however, the prevalence of positive scorings was low for some subcategories. The modified Peetrons grading system, overall Chan classification and overall British Athletics Muscle Injury Classification demonstrated 'substantial' to 'almost perfect' intra- and interrater reliability when scored by experienced radiologists. The intra- and interrater reliability for the anatomical subcategories within the classifications remains unclear. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Grading of Crohn's disease activity using CT, MRI, US and scintigraphy: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Puylaert, C.A.J.; Tielbeek, J.A.W.; Bipat, S.; Stoker, J. [University of Amsterdam, Academic Medical Center, Department of Radiology, Amsterdam (Netherlands)

    2015-11-15

    To assess the grading of Crohn's disease activity using CT, MRI, US and scintigraphy. MEDLINE, EMBASE and Cochrane databases were searched (January 1983-March 2014) for studies evaluating CT, MRI, US and scintigraphy in grading Crohn's disease activity compared to endoscopy, biopsies or intraoperative findings. Two independent reviewers assessed the data. Three-by-three tables (none, mild, frank disease) were constructed for all studies, and estimates of accurate, over- and under-grading were calculated/summarized by fixed or random effects models. Our search yielded 9356 articles, 19 of which were included. Per-patient data showed accurate grading values for CT, MRI, US and scintigraphy of 86 % (95 % CI: 75-93 %), 84 % (95 % CI: 67-93 %), 44 % (95 % CI: 28-61 %) and 40 % (95 % CI: 16-70 %), respectively. In the per-patient analysis, CT and MRI showed similar accurate grading estimates (P = 0.8). Per-segment data showed accurate grading values for CT and scintigraphy of 87 % (95 % CI: 77-93 %) and 86 % (95 % CI: 80-91 %), respectively. MRI and US showed grading accuracies of 67-82 % and 56-75 %, respectively. CT and MRI showed comparable high accurate grading estimates in the per-patient analysis. Results for US and scintigraphy were inconsistent, and limited data were available. (orig.)

  16. Dynamic Contrast-Enhanced Perfusion MRI of High Grade Brain Gliomas Obtained with Arterial or Venous Waveform Input Function.

    Science.gov (United States)

    Filice, Silvano; Crisi, Girolamo

    2016-01-01

    The aim of this study was to evaluate the differences in dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) perfusion estimates of high-grade brain gliomas (HGG) due to the use of an input function (IF) obtained respectively from arterial (AIF) and venous (VIF) approaches by two different commercially available software applications. This prospective study includes 20 patients with pathologically confirmed diagnosis of high-grade gliomas. The data source was processed by using two DCE dedicated commercial packages, both based on the extended Toft model, but the first customized to obtain input function from arterial measurement and the second from sagittal sinus sampling. The quantitative parametric perfusion maps estimated from the two software packages were compared by means of a region of interest (ROI) analysis. The resulting input functions from venous and arterial data were also compared. No significant difference has been found between the perfusion parameters obtained with the two different software packages (P-value < .05). The comparison of the VIFs and AIFs obtained by the two packages showed no statistical differences. Direct comparison of DCE-MRI measurements with IF generated by means of arterial or venous waveform led to no statistical difference in quantitative metrics for evaluating HGG. However, additional research involving DCE-MRI acquisition protocols and post-processing would be beneficial to further substantiate the effectiveness of venous approach as the IF method compared with arterial-based IF measurement. Copyright © 2015 by the American Society of Neuroimaging.

  17. Diffusion-weighted MRI of epithelial ovarian cancers: Correlation of apparent diffusion coefficient values with histologic grade and surgical stage

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Ji-Won, E-mail: fromentin@naver.com [Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701 (Korea, Republic of); Rha, Sung Eun, E-mail: serha@catholic.ac.kr [Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701 (Korea, Republic of); Oh, Soon Nam, E-mail: hiohsn@catholic.ac.kr [Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701 (Korea, Republic of); Park, Michael Yong, E-mail: digirave@kmle.com [Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701 (Korea, Republic of); Byun, Jae Young, E-mail: jybyun@catholic.ac.kr [Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701 (Korea, Republic of); Lee, Ahwon, E-mail: klee@catholic.ac.kr [Department of Hospital Pathology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701 (Korea, Republic of)

    2015-04-15

    Highlights: •The solid component of all invasive epithelial cancers showed high b{sub 1000} signal intensity. •ADCs can predict the histologic grade of epithelial ovarian cancer. •ADCs correlate negatively to the surgical stage of epithelial ovarian cancer. •ADCs may be useful imaging biomarkers to assess epithelial ovarian cancer. -- Abstract: Objective: The purpose of this article is to correlate the apparent diffusion coefficient (ADC) values of epithelial ovarian cancers with histologic grade and surgical stage. Materials and methods: We enrolled 43 patients with pathologically proven epithelial ovarian cancers for this retrospective study. All patients underwent preoperative pelvic magnetic resonance imaging (MRI) including diffusion-weighted images with b value of 0 and 1000 s/mm{sup 2} at 3.0-T unit. The mean ADC values of the solid portion of the tumor were measured and compared among different histologic grades and surgical stages. Results: The mean ADC values of epithelial ovarian cancers differed significantly between grade 1 (well-differentiated) and grade 2 (moderately-differentiated) (P = 0.013) as well as between grade 1 and grade 3 (poorly-differentiated) (P = 0.01); however, no statistically significant difference existed between grade 2 and grade 3 (P = 0.737). The receiver-operating characteristic analysis indicated that a cutoff ADC value of less than or equal to 1.09 × 10{sup −3} mm{sup 2}/s was associated with 94.4% sensitivity and 85.7% specificity in distinguishing grade 1 and grade 2/3 cancer. The difference in mean ADC values was statistically significant for early stage (FIGO stage I) and advanced stage (FIGO stage II-IV) cancer (P = 0.011). The interobserver agreement for the mean ADC values of epithelial ovarian cancers was excellent. Conclusion: The mean ADC values of the solid portion of epithelial ovarian cancers negatively correlated to histologic grade and surgical stage. The mean ADC values may be useful imaging

  18. A Novel Marker Based Method to Teeth Alignment in MRI

    Science.gov (United States)

    Luukinen, Jean-Marc; Aalto, Daniel; Malinen, Jarmo; Niikuni, Naoko; Saunavaara, Jani; Jääsaari, Päivi; Ojalammi, Antti; Parkkola, Riitta; Soukka, Tero; Happonen, Risto-Pekka

    2018-04-01

    Magnetic resonance imaging (MRI) can precisely capture the anatomy of the vocal tract. However, the crowns of teeth are not visible in standard MRI scans. In this study, a marker-based teeth alignment method is presented and evaluated. Ten patients undergoing orthognathic surgery were enrolled. Supraglottal airways were imaged preoperatively using structural MRI. MRI visible markers were developed, and they were attached to maxillary teeth and corresponding locations on the dental casts. Repeated measurements of intermarker distances in MRI and in a replica model was compared using linear regression analysis. Dental cast MRI and corresponding caliper measurements did not differ significantly. In contrast, the marker locations in vivo differed somewhat from the dental cast measurements likely due to marker placement inaccuracies. The markers were clearly visible in MRI and allowed for dental models to be aligned to head and neck MRI scans.

  19. Population based ranking of frameless CT-MRI registration methods

    Energy Technology Data Exchange (ETDEWEB)

    Opposits, Gabor; Kis, Sandor A.; Tron, Lajos; Emri, Miklos [Debrecen Univ. (Hungary). Dept. of Nuclear Medicine; Berenyi, Ervin [Debrecen Univ. (Hungary). Dept. of Biomedical Laboratory and Imaging Science; Takacs, Endre [Rotating Gamma Ltd., Debrecen (Hungary); Dobai, Jozsef G.; Bognar, Laszlo [Debrecen Univ., Medical Center (Hungary). Dept. of Neurosurgery; Szuecs, Bernadett [ScanoMed Ltd., Debrecen (Hungary)

    2015-07-01

    Clinical practice often requires simultaneous information obtained by two different imaging modalities. Registration algorithms are commonly used for this purpose. Automated procedures are very helpful in cases when the same kind of registration has to be performed on images of a high number of subjects. Radiotherapists would prefer to use the best automated method to assist therapy planning, however there are not accepted procedures for ranking the different registration algorithms. We were interested in developing a method to measure the population level performance of CT-MRI registration algorithms by a parameter of values in the [0,1] interval. Pairs of CT and MRI images were collected from 1051 subjects. Results of an automated registration were corrected manually until a radiologist and a neurosurgeon expert both accepted the result as good. This way 1051 registered MRI images were produced by the same pair of experts to be used as gold standards for the evaluation of the performance of other registration algorithms. Pearson correlation coefficient, mutual information, normalized mutual information, Kullback-Leibler divergence, L{sub 1} norm and square L{sub 2} norm (dis)similarity measures were tested for sensitivity to indicate the extent of (dis)similarity of a pair of individual mismatched images. The square Hellinger distance proved suitable to grade the performance of registration algorithms at population level providing the developers with a valuable tool to rank algorithms. The developed procedure provides an objective method to find the registration algorithm performing the best on the population level out of newly constructed or available preselected ones.

  20. Training readers to improve their accuracy in grading Crohn's disease activity on MRI

    International Nuclear Information System (INIS)

    Tielbeek, Jeroen A.W.; Bipat, Shandra; Boellaard, Thierry N.; Nio, C.Y.; Stoker, Jaap

    2014-01-01

    To prospectively evaluate if training with direct feedback improves grading accuracy of inexperienced readers for Crohn's disease activity on magnetic resonance imaging (MRI). Thirty-one inexperienced readers assessed 25 cases as a baseline set. Subsequently, all readers received training and assessed 100 cases with direct feedback per case, randomly assigned to four sets of 25 cases. The cases in set 4 were identical to the baseline set. Grading accuracy, understaging, overstaging, mean reading times and confidence scores (scale 0-10) were compared between baseline and set 4, and between the four consecutive sets with feedback. Proportions of grading accuracy, understaging and overstaging per set were compared using logistic regression analyses. Mean reading times and confidence scores were compared by t-tests. Grading accuracy increased from 66 % (95 % CI, 56-74 %) at baseline to 75 % (95 % CI, 66-81 %) in set 4 (P = 0.003). Understaging decreased from 15 % (95 % CI, 9-23 %) to 7 % (95 % CI, 3-14 %) (P < 0.001). Overstaging did not change significantly (20 % vs 19 %). Mean reading time decreased from 6 min 37 s to 4 min 35 s (P < 0.001). Mean confidence increased from 6.90 to 7.65 (P < 0.001). During training, overall grading accuracy, understaging, mean reading times and confidence scores improved gradually. Inexperienced readers need training with at least 100 cases to achieve the literature reported grading accuracy of 75 %. (orig.)

  1. Longitudinal DSC-MRI for Distinguishing Tumor Recurrence From Pseudoprogression in Patients With a High-grade Glioma.

    Science.gov (United States)

    Boxerman, Jerrold L; Ellingson, Benjamin M; Jeyapalan, Suriya; Elinzano, Heinrich; Harris, Robert J; Rogg, Jeffrey M; Pope, Whitney B; Safran, Howard

    2017-06-01

    For patients with high-grade glioma on clinical trials it is important to accurately assess time of disease progression. However, differentiation between pseudoprogression (PsP) and progressive disease (PD) is unreliable with standard magnetic resonance imaging (MRI) techniques. Dynamic susceptibility contrast perfusion MRI (DSC-MRI) can measure relative cerebral blood volume (rCBV) and may help distinguish PsP from PD. A subset of patients with high-grade glioma on a phase II clinical trial with temozolomide, paclitaxel poliglumex, and concurrent radiation were assessed. Nine patients (3 grade III, 6 grade IV), with a total of 19 enhancing lesions demonstrating progressive enhancement (≥25% increase from nadir) on postchemoradiation conventional contrast-enhanced MRI, had serial DSC-MRI. Mean leakage-corrected rCBV within enhancing lesions was computed for all postchemoradiation time points. Of the 19 progressively enhancing lesions, 10 were classified as PsP and 9 as PD by biopsy/surgery or serial enhancement patterns during interval follow-up MRI. Mean rCBV at initial progressive enhancement did not differ significantly between PsP and PD (2.35 vs. 2.17; P=0.67). However, change in rCBV at first subsequent follow-up (-0.84 vs. 0.84; P=0.001) and the overall linear trend in rCBV after initial progressive enhancement (negative vs. positive slope; P=0.04) differed significantly between PsP and PD. Longitudinal trends in rCBV may be more useful than absolute rCBV in distinguishing PsP from PD in chemoradiation-treated high-grade gliomas with DSC-MRI. Further studies of DSC-MRI in high-grade glioma as a potential technique for distinguishing PsP from PD are indicated.

  2. Volume Equalization Method for Land Grading Design: Uniform ...

    African Journals Online (AJOL)

    muğla üniversitesi

    2011-05-23

    May 23, 2011 ... *Corresponding author. E-mail: ... Land grading has been in practice for a long time, but land-grading ... method was based on least-squares theory and he showed its ... Srinisava (1996) developed a nonlinear optimization.

  3. Analysis and visualization methods for interpretation of diffusion MRI data

    NARCIS (Netherlands)

    Vos, S.B.

    2013-01-01

    Diffusion MRI is an imaging technique that is very sensitive to microstructural changes in tissue. Diffusion tensor MRI, the most commonly used method, can estimate the magnitude and anisotropy of diffusion. These tensor-based diffusion parameters have been shown to change in many neuropathological

  4. Perfusion MRI derived indices of microvascular shunting and flow control correlate with tumor grade and outcome in patients with cerebral glioma

    DEFF Research Database (Denmark)

    Tietze, Anna; Mouridsen, Kim; Lassen-Ramshad, Yasmin

    2015-01-01

    Objectives: Deficient microvascular blood flow control is thought to cause tumor hypoxia and increase resistance to therapy. In glioma patients, we tested whether perfusion-weighted MRI (PWI) based indices of microvascular flow control provide more information on tumor grade and patient outcome...... than does the established PWI angiogenesis marker, cerebral blood volume (CBV). Material and Methods: Seventy-two glioma patients (sixty high-grade, twelve low-grade gliomas) were included. Capillary transit time heterogeneity (CTH) and COV, its ratio to blood mean transit time, provide indices...... of microvascular flow control and the extent to which oxygen can be extracted by tumor tissue. The ability of these parameters and CBV to differentiate tumor grade were assessed by receiver operating characteristic curves and logistic regression. Their ability to predict time to progression and overall survival...

  5. Semiautomatic segmentation and follow-up of multicomponent low-grade tumors in longitudinal brain MRI studies

    International Nuclear Information System (INIS)

    Weizman, Lior; Sira, Liat Ben; Joskowicz, Leo; Rubin, Daniel L.; Yeom, Kristen W.; Constantini, Shlomi; Shofty, Ben; Bashat, Dafna Ben

    2014-01-01

    Purpose: Tracking the progression of low grade tumors (LGTs) is a challenging task, due to their slow growth rate and associated complex internal tumor components, such as heterogeneous enhancement, hemorrhage, and cysts. In this paper, the authors show a semiautomatic method to reliably track the volume of LGTs and the evolution of their internal components in longitudinal MRI scans. Methods: The authors' method utilizes a spatiotemporal evolution modeling of the tumor and its internal components. Tumor components gray level parameters are estimated from the follow-up scan itself, obviating temporal normalization of gray levels. The tumor delineation procedure effectively incorporates internal classification of the baseline scan in the time-series as prior data to segment and classify a series of follow-up scans. The authors applied their method to 40 MRI scans of ten patients, acquired at two different institutions. Two types of LGTs were included: Optic pathway gliomas and thalamic astrocytomas. For each scan, a “gold standard” was obtained manually by experienced radiologists. The method is evaluated versus the gold standard with three measures: gross total volume error, total surface distance, and reliability of tracking tumor components evolution. Results: Compared to the gold standard the authors' method exhibits a mean Dice similarity volumetric measure of 86.58% and a mean surface distance error of 0.25 mm. In terms of its reliability in tracking the evolution of the internal components, the method exhibits strong positive correlation with the gold standard. Conclusions: The authors' method provides accurate and repeatable delineation of the tumor and its internal components, which is essential for therapy assessment of LGTs. Reliable tracking of internal tumor components over time is novel and potentially will be useful to streamline and improve follow-up of brain tumors, with indolent growth and behavior

  6. Detecting Alzheimer’s disease by morphological MRI using hippocampal grading and cortical thickness

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Coupé, Pierrick; Fonov, Vladimir

    2014-01-01

    effort has been dedicated to separate AD related modifications from normal ag-ing for the purpose of early detection and prediction. Several groups have re-ported promising results using automatic methods; however, it is very difficult to compare these methods due to varying cohorts and different...... validation frameworks. To address this issue, the public challenge on Computer-Aided Di-agnosis of Dementia based on structural MRI data (CADDementia) was pro-posed. The challenge calls for accurate classification of 354 MRI scans collect-ed among AD patients, subjects with mild cognitive impairment...... and cognitively normal control. The true diagnosis is hidden from the participating groups, thus making the validation truly objective. This paper describes our proposed meth-od to automatically classify the challenge data along with a validation on 30 scans with known diagnosis also provided for the challenge....

  7. Accuracy of high-field intraoperative MRI in the detectability of residual tumor in glioma grade IV resections

    Energy Technology Data Exchange (ETDEWEB)

    Hesselmann, Volker; Mager, Ann-Kathrin [Asklepios-Klinik Nord, Hamburg (Germany). Radiology/Neurologie; Goetz, Claudia; Kremer, Paul [Asklepios-Klinik Nord, Hamburg (Germany). Dept. of Neurosurgery; Detsch, Oliver [Asklepios-Klinik Nord, Hamburg (Germany). Dept. of Anaesthesiology and Intensive Care Medicine; Theisgen, Hannah-Katharina [Universitaetsklinikum Schleswig-Holstein, Kiel (Germany). Dept. of Neurosurgery; Friese, Michael; Gottschalk, Joachim [Asklepios-Klinik Nord, Hamburg (Germany). Dept. of Pathology and Neuropathology; Schwindt, Wolfram [Univ. Hospital Muenster (Germany). Dept. of Clinical Radiology

    2017-06-15

    To assess the sensitivity/specificity of tumor detection by T1 contrast enhancement in intraoperative MRI (ioMRI) in comparison to histopathological assessment as the gold standard in patients receiving surgical resection of grade IV glioblastoma. 68 patients with a primary or a recurrent glioblastoma scheduled for surgery including fluorescence guidance and neuronavigation were included (mean age: 59 years, 26 female, 42 male patients). The ioMRI after the first resection included transverse FLAIR, DWI, T2-FFE and T1 - 3 d FFE ± GD-DPTA. The second resection was performed whenever residual contrast-enhancing tissue was detected on ioMRI. Resected tissue samples were histopathologically evaluated (gold standard). Additionally, we evaluated the early postoperative MRI scan acquired within 48 h post-OP for remaining enhancing tissue and compared them with the ioMRI scan. In 43 patients ioMRI indicated residual tumorous tissue, which could be confirmed in the histological specimens of the second resection. In 16 (4 with recurrent, 12 with primary glioblastoma) cases, ioMRI revealed truly negative results without residual tumor and follow-up MRI confirmed complete resection. In 7 cases (3 with recurrent, 4 with primary glioblastoma) ioMRI revealed a suspicious result without tumorous tissue in the histopathological workup. In 2 (1 for each group) patients, residual tumorous tissue was detected in spite of negative ioMRI. IoMRI had a sensitivity of 95 % (94 % recurrent and 96 % for primary glioblastoma) and a specificity of 69.5 % (57 % and 75 %, respectively). The positive predictive value was 86 % (84 % for recurrent and 87 % for primary glioblastoma), and the negative predictive value was 88 % (80 % and 92 %, respectively). ioMRI is effective for detecting remaining tumorous tissue after glioma resection. However, scars and leakage of contrast agent can be misleading and limit specificity. Intraoperative MRI (ioMRI) presents with a high sensitivity for residual

  8. Accuracy of high-field intraoperative MRI in the detectability of residual tumor in glioma grade IV resections

    International Nuclear Information System (INIS)

    Hesselmann, Volker; Mager, Ann-Kathrin; Goetz, Claudia; Kremer, Paul; Detsch, Oliver; Theisgen, Hannah-Katharina; Friese, Michael; Gottschalk, Joachim; Schwindt, Wolfram

    2017-01-01

    To assess the sensitivity/specificity of tumor detection by T1 contrast enhancement in intraoperative MRI (ioMRI) in comparison to histopathological assessment as the gold standard in patients receiving surgical resection of grade IV glioblastoma. 68 patients with a primary or a recurrent glioblastoma scheduled for surgery including fluorescence guidance and neuronavigation were included (mean age: 59 years, 26 female, 42 male patients). The ioMRI after the first resection included transverse FLAIR, DWI, T2-FFE and T1 - 3 d FFE ± GD-DPTA. The second resection was performed whenever residual contrast-enhancing tissue was detected on ioMRI. Resected tissue samples were histopathologically evaluated (gold standard). Additionally, we evaluated the early postoperative MRI scan acquired within 48 h post-OP for remaining enhancing tissue and compared them with the ioMRI scan. In 43 patients ioMRI indicated residual tumorous tissue, which could be confirmed in the histological specimens of the second resection. In 16 (4 with recurrent, 12 with primary glioblastoma) cases, ioMRI revealed truly negative results without residual tumor and follow-up MRI confirmed complete resection. In 7 cases (3 with recurrent, 4 with primary glioblastoma) ioMRI revealed a suspicious result without tumorous tissue in the histopathological workup. In 2 (1 for each group) patients, residual tumorous tissue was detected in spite of negative ioMRI. IoMRI had a sensitivity of 95 % (94 % recurrent and 96 % for primary glioblastoma) and a specificity of 69.5 % (57 % and 75 %, respectively). The positive predictive value was 86 % (84 % for recurrent and 87 % for primary glioblastoma), and the negative predictive value was 88 % (80 % and 92 %, respectively). ioMRI is effective for detecting remaining tumorous tissue after glioma resection. However, scars and leakage of contrast agent can be misleading and limit specificity. Intraoperative MRI (ioMRI) presents with a high sensitivity for residual

  9. Advanced soft computing diagnosis method for tumour grading.

    Science.gov (United States)

    Papageorgiou, E I; Spyridonos, P P; Stylios, C D; Ravazoula, P; Groumpos, P P; Nikiforidis, G N

    2006-01-01

    To develop an advanced diagnostic method for urinary bladder tumour grading. A novel soft computing modelling methodology based on the augmentation of fuzzy cognitive maps (FCMs) with the unsupervised active Hebbian learning (AHL) algorithm is applied. One hundred and twenty-eight cases of urinary bladder cancer were retrieved from the archives of the Department of Histopathology, University Hospital of Patras, Greece. All tumours had been characterized according to the classical World Health Organization (WHO) grading system. To design the FCM model for tumour grading, three experts histopathologists defined the main histopathological features (concepts) and their impact on grade characterization. The resulted FCM model consisted of nine concepts. Eight concepts represented the main histopathological features for tumour grading. The ninth concept represented the tumour grade. To increase the classification ability of the FCM model, the AHL algorithm was applied to adjust the weights of the FCM. The proposed FCM grading model achieved a classification accuracy of 72.5%, 74.42% and 95.55% for tumours of grades I, II and III, respectively. An advanced computerized method to support tumour grade diagnosis decision was proposed and developed. The novelty of the method is based on employing the soft computing method of FCMs to represent specialized knowledge on histopathology and on augmenting FCMs ability using an unsupervised learning algorithm, the AHL. The proposed method performs with reasonably high accuracy compared to other existing methods and at the same time meets the physicians' requirements for transparency and explicability.

  10. Science Teaching Methods Preferred by Grade 9 Students in Finland

    Science.gov (United States)

    Juuti, Kalle; Lavonen, Jari; Uitto, Anna; Byman, Reijo; Meisalo, Veijo

    2010-01-01

    Students find science relevant to society, but they do not find school science interesting. This survey study analyzes Finnish grade 9 students' actual experiences with science teaching methods and their preferences for how they would like to study science. The survey data were collected from 3,626 grade 9 students (1,772 girls and 1,832 boys)…

  11. Statistical Analysis Methods for the fMRI Data

    Directory of Open Access Journals (Sweden)

    Huseyin Boyaci

    2011-08-01

    Full Text Available Functional magnetic resonance imaging (fMRI is a safe and non-invasive way to assess brain functions by using signal changes associated with brain activity. The technique has become a ubiquitous tool in basic, clinical and cognitive neuroscience. This method can measure little metabolism changes that occur in active part of the brain. We process the fMRI data to be able to find the parts of brain that are involve in a mechanism, or to determine the changes that occur in brain activities due to a brain lesion. In this study we will have an overview over the methods that are used for the analysis of fMRI data.

  12. Prostate cancer diagnosis: Efficacy of a simple electromagnetic MRI-TRUS fusion method to target biopsies

    International Nuclear Information System (INIS)

    Jelidi, Amina; Ohana, Mickael; Labani, Aïssam; Alemann, Guillaume; Lang, Herve; Roy, Catherine

    2017-01-01

    Highlights: • A very simple electromagnetic device for fusion with MRI examination during TRUS guided biopsies increases the detection of clinically significant prostate cancer. • This device has advantages: a short time for the fusion registration, no additional cumbersome material and no intense training to be fluent with. • Low or intermediate suspicious area for prostate carcinoma on mpMRI can be due to benign histological abnormalities or high grade prostatic intraepithelial neoplasia. - Abstract: Objective: To assess that transrectal ultrasound guidance (TRUS) targeted biopsies (TB) aimed with an easy to use electronic real-time fusion registration device have a higher rate of prostate cancer (PC) detection than standard biopsies (SB). Material and methods: This prospective study included 130 patients referred for TRUS biopsies after suspicious MRI. They underwent 16-core SB and 2 to 3 cores in each MRI suspicious area, using a fusion software. We noted SB and TB positivity for PC and Gleason score (GS). We used the McNemar test to compare SB and TB, with a statistical significance p < 0.05. Results: Among 130 patients, 68.5% had PC. Additional time due to the fusion registration was 3.3 min. One hundred fifteen patients (88.4%) had pathological findings on the histological analysis (prostate cancer n = 89, others n = 26). TB diagnosed PC in 75 patients with negative SB. Positivity rate for PC was significantly higher for TB than SB (p = 0.03). Among highly suspicious MRI lesions, detection rate of histological abnormalities using SB and TB was 96% with 79.7% of PC. Most PC that TB diagnosed alone were clinically significant (86.3%). Conclusion: TRUS biopsies performed with a simple MRI and US electronic fusion is an unrestrainedly method to increase PC diagnosis.

  13. Typing of MRI in medial meniscus degeneration in relation to radiological grade in medial compartmental osteoarthritis of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Nobuhito; Koshino, Tomihisa; Saito, Tomoyuki; Sakai, Naotaka; Takagi, Toshitaka; Takeuchi, Ryohei [Yokohama City Univ. (Japan). School of Medicine

    1998-10-01

    The advancement of degeneration of 50 medial menisci in patients with medial compartmental osteoarthritic knees (OA) were evaluated with magnetic resonance imaging (MRI). The average age of the patients was 66.6 years (range, 39 to 86). According to a radiographical grading system, 6 knees were classified as Grade 1, 24 as Grade 2, 16 as Grade 3, and 4 as Grade 4. The extent and the location of a high intensity region in MRI were observed in 3 parts of the meniscus, namely, the anterior, middle and posterior part. In Grade 1, no high intensity region was observed in 3 knees, and a high intensity region was observed only in the posterior part in 2 knees. A high intensity region was observed from the medial to the posterior part in 13 knees, and only in the posterior part in 10 knees of Grade 2; from the medial to the posterior part in 12 knees, and only in the posterior part in 3 knees of Grade 3, and from the anterior to the posterior part in 2 knees of Grade 4. The shape of the high intensity region in the medial meniscus was classified into 5 types, as follows: Type 1, there was no high intensity region; Type 2, the high intensity region was observed to be restricted within the meniscus; Type 3, the high intensity region resembled a horizontal tear; Type 4, the high intensity region was observed as all of the medial joint space without a marginal area; Type 5, the high intensity region was observed as all of the medial joint space. In Grade 1, 3 knees were classified as Type 1, and 2 knees as Type 2; in Grade 2, 7 knees as Type 2, and 13 knees as Type 3, and 4 knees into Type 4; in Grade 3, 6 knees as Type 3, and 7 knees as Type 4; and in Grade 4, 2 knees as Type 4, and 2 knees as Type 5. These findings might suggest that the degeneration of medial meniscus in the medial type of OA was accelerated by mechanical stress due to varus deformity. (author)

  14. Typing of MRI in medial meniscus degeneration in relation to radiological grade in medial compartmental osteoarthritis of the knee

    International Nuclear Information System (INIS)

    Nagata, Nobuhito; Koshino, Tomihisa; Saito, Tomoyuki; Sakai, Naotaka; Takagi, Toshitaka; Takeuchi, Ryohei

    1998-01-01

    The advancement of degeneration of 50 medial menisci in patients with medial compartmental osteoarthritic knees (OA) were evaluated with magnetic resonance imaging (MRI). The average age of the patients was 66.6 years (range, 39 to 86). According to a radiographical grading system, 6 knees were classified as Grade 1, 24 as Grade 2, 16 as Grade 3, and 4 as Grade 4. The extent and the location of a high intensity region in MRI were observed in 3 parts of the meniscus, namely, the anterior, middle and posterior part. In Grade 1, no high intensity region was observed in 3 knees, and a high intensity region was observed only in the posterior part in 2 knees. A high intensity region was observed from the medial to the posterior part in 13 knees, and only in the posterior part in 10 knees of Grade 2; from the medial to the posterior part in 12 knees, and only in the posterior part in 3 knees of Grade 3, and from the anterior to the posterior part in 2 knees of Grade 4. The shape of the high intensity region in the medial meniscus was classified into 5 types, as follows: Type 1, there was no high intensity region; Type 2, the high intensity region was observed to be restricted within the meniscus; Type 3, the high intensity region resembled a horizontal tear; Type 4, the high intensity region was observed as all of the medial joint space without a marginal area; Type 5, the high intensity region was observed as all of the medial joint space. In Grade 1, 3 knees were classified as Type 1, and 2 knees as Type 2; in Grade 2, 7 knees as Type 2, and 13 knees as Type 3, and 4 knees into Type 4; in Grade 3, 6 knees as Type 3, and 7 knees as Type 4; and in Grade 4, 2 knees as Type 4, and 2 knees as Type 5. These findings might suggest that the degeneration of medial meniscus in the medial type of OA was accelerated by mechanical stress due to varus deformity. (author)

  15. Facing Contrast-Enhancing Gliomas: Perfusion MRI in Grade III and Grade IV Gliomas according to Tumor Area

    Directory of Open Access Journals (Sweden)

    Anna Luisa Di Stefano

    2014-01-01

    Full Text Available Tumoral neoangiogenesis characterizes high grade gliomas. Relative Cerebral Blood Volume (rCBV, calculated with Dynamic Susceptibility Contrast (DSC Perfusion-Weighted Imaging (PWI, allows for the estimation of vascular density over the tumor bed. The aim of the study was to characterize putative tumoral neoangiogenesis via the study of maximal rCBV with a Region of Interest (ROI approach in three tumor areas—the contrast-enhancing area, the nonenhancing tumor, and the high perfusion area on CBV map—in patients affected by contrast-enhancing glioma (grades III and IV. Twenty-one patients were included: 15 were affected by grade IV and 6 by grade III glioma. Maximal rCBV values for each patient were averaged according to glioma grade. Although rCBV from contrast-enhancement and from nonenhancing tumor areas was higher in grade IV glioma than in grade III (5.58 and 2.68; 3.01 and 2.2, resp., the differences were not significant. Instead, rCBV recorded in the high perfusion area on CBV map, independently of tumor compartment, was significantly higher in grade IV glioma than in grade III (7.51 versus 3.78, P=0.036. In conclusion, neoangiogenesis encompasses different tumor compartments and CBV maps appear capable of best characterizing the degree of neovascularization. Facing contrast-enhancing brain tumors, areas of high perfusion on CBV maps should be considered as the reference areas to be targeted for glioma grading.

  16. Mathematical methods for diffusion MRI processing

    International Nuclear Information System (INIS)

    Lenglet, C.; Lenglet, C.; Sapiro, G.; Campbell, J.S.W.; Pike, G.B.; Campbell, J.S.W.; Siddiqi, K.; Descoteaux, M.; Haro, G.; Wassermann, D.; Deriche, R.; Wassermann, D.; Anwander, A.; Thompson, P.M.

    2009-01-01

    In this article, we review recent mathematical models and computational methods for the processing of diffusion Magnetic Resonance Images, including state-of-the-art reconstruction of diffusion models, cerebral white matter connectivity analysis, and segmentation techniques. We focus on Diffusion Tensor Images (DTI) and Q-Ball Images (QBI). (authors)

  17. Separation of type and grade in cervical tumours using non-mono-exponential models of diffusion-weighted MRI

    International Nuclear Information System (INIS)

    Winfield, Jessica M.; Collins, David J.; Morgan, Veronica A.; DeSouza, Nandita M.; Orton, Matthew R.; Ind, Thomas E.J.; Attygalle, Ayoma; Hazell, Steve

    2017-01-01

    Assessment of empirical diffusion-weighted MRI (DW-MRI) models in cervical tumours to investigate whether fitted parameters distinguish between types and grades of tumours. Forty-two patients (24 squamous cell carcinomas, 14 well/moderately differentiated, 10 poorly differentiated; 15 adenocarcinomas, 13 well/moderately differentiated, two poorly differentiated; three rare types) were imaged at 3 T using nine b-values (0 to 800 s mm -2 ). Mono-exponential, stretched exponential, kurtosis, statistical, and bi-exponential models were fitted. Model preference was assessed using Bayesian Information Criterion analysis. Differences in fitted parameters between tumour types/grades and correlation between fitted parameters were assessed using two-way analysis of variance and Pearson's linear correlation coefficient, respectively. Non-mono-exponential models were preferred by 83 % of tumours with bi-exponential and stretched exponential models preferred by the largest numbers of tumours. Apparent diffusion coefficient (ADC) and diffusion coefficients from non-mono-exponential models were significantly lower in poorly differentiated tumours than well/moderately differentiated tumours. α (stretched exponential), K (kurtosis), f and D* (bi-exponential) were significantly different between tumour types. Strong correlation was observed between ADC and diffusion coefficients from other models. Non-mono-exponential models were preferred to the mono-exponential model in DW-MRI data from cervical tumours. Parameters of non-mono-exponential models showed significant differences between types and grades of tumours. (orig.)

  18. Separation of type and grade in cervical tumours using non-mono-exponential models of diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Winfield, Jessica M.; Collins, David J.; Morgan, Veronica A.; DeSouza, Nandita M. [The Royal Marsden NHS Foundation Trust, MRI Unit, Sutton, Surrey (United Kingdom); The Institute of Cancer Research, Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, London (United Kingdom); Orton, Matthew R. [The Institute of Cancer Research, Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, London (United Kingdom); Ind, Thomas E.J. [The Royal Marsden NHS Foundation Trust, Gynaecology Unit, London (United Kingdom); Attygalle, Ayoma; Hazell, Steve [The Royal Marsden NHS Foundation Trust, Department of Histopathology, London (United Kingdom)

    2017-02-15

    Assessment of empirical diffusion-weighted MRI (DW-MRI) models in cervical tumours to investigate whether fitted parameters distinguish between types and grades of tumours. Forty-two patients (24 squamous cell carcinomas, 14 well/moderately differentiated, 10 poorly differentiated; 15 adenocarcinomas, 13 well/moderately differentiated, two poorly differentiated; three rare types) were imaged at 3 T using nine b-values (0 to 800 s mm{sup -2}). Mono-exponential, stretched exponential, kurtosis, statistical, and bi-exponential models were fitted. Model preference was assessed using Bayesian Information Criterion analysis. Differences in fitted parameters between tumour types/grades and correlation between fitted parameters were assessed using two-way analysis of variance and Pearson's linear correlation coefficient, respectively. Non-mono-exponential models were preferred by 83 % of tumours with bi-exponential and stretched exponential models preferred by the largest numbers of tumours. Apparent diffusion coefficient (ADC) and diffusion coefficients from non-mono-exponential models were significantly lower in poorly differentiated tumours than well/moderately differentiated tumours. α (stretched exponential), K (kurtosis), f and D* (bi-exponential) were significantly different between tumour types. Strong correlation was observed between ADC and diffusion coefficients from other models. Non-mono-exponential models were preferred to the mono-exponential model in DW-MRI data from cervical tumours. Parameters of non-mono-exponential models showed significant differences between types and grades of tumours. (orig.)

  19. Automatic MRI Quantifying Methods in Behavioral-Variant Frontotemporal Dementia Diagnosis

    Directory of Open Access Journals (Sweden)

    Antti Cajanus

    2018-02-01

    Full Text Available Aims: We assessed the value of automated MRI quantification methods in the differential diagnosis of behavioral-variant frontotemporal dementia (bvFTD from Alzheimer disease (AD, Lewy body dementia (LBD, and subjective memory complaints (SMC. We also examined the role of the C9ORF72-related genetic status in the differentiation sensitivity. Methods: The MRI scans of 50 patients with bvFTD (17 C9ORF72 expansion carriers were analyzed using 6 quantification methods as follows: voxel-based morphometry (VBM, tensor-based morphometry, volumetry (VOL, manifold learning, grading, and white-matter hyperintensities. Each patient was then individually compared to an independent reference group in order to attain diagnostic suggestions. Results: Only VBM and VOL showed utility in correctly identifying bvFTD from our set of data. The overall classification sensitivity of bvFTD with VOL + VBM achieved a total sensitivity of 60%. Using VOL + VBM, 32% were misclassified as having LBD. There was a trend of higher values for classification sensitivity of the C9ORF72 expansion carriers than noncarriers. Conclusion: VOL, VBM, and their combination are effective in differential diagnostics between bvFTD and AD or SMC. However, MRI atrophy profiles for bvFTD and LBD are too similar for a reliable differentiation with the quantification methods tested in this study.

  20. Segmentation of solid subregion of high grade gliomas in MRI images based on active contour model (ACM)

    Science.gov (United States)

    Seow, P.; Win, M. T.; Wong, J. H. D.; Abdullah, N. A.; Ramli, N.

    2016-03-01

    Gliomas are tumours arising from the interstitial tissue of the brain which are heterogeneous, infiltrative and possess ill-defined borders. Tumour subregions (e.g. solid enhancing part, edema and necrosis) are often used for tumour characterisation. Tumour demarcation into substructures facilitates glioma staging and provides essential information. Manual segmentation had several drawbacks that include laborious, time consuming, subjected to intra and inter-rater variability and hindered by diversity in the appearance of tumour tissues. In this work, active contour model (ACM) was used to segment the solid enhancing subregion of the tumour. 2D brain image acquisition data using 3T MRI fast spoiled gradient echo sequence in post gadolinium of four histologically proven high-grade glioma patients were obtained. Preprocessing of the images which includes subtraction and skull stripping were performed and then followed by ACM segmentation. The results of the automatic segmentation method were compared against the manual delineation of the tumour by a trainee radiologist. Both results were further validated by an experienced neuroradiologist and a brief quantitative evaluations (pixel area and difference ratio) were performed. Preliminary results of the clinical data showed the potential of ACM model in the application of fast and large scale tumour segmentation in medical imaging.

  1. Segmentation of solid subregion of high grade gliomas in MRI images based on active contour model (ACM)

    International Nuclear Information System (INIS)

    Seow, P; Win, M T; Wong, J H D; Ramli, N; Abdullah, N A

    2016-01-01

    Gliomas are tumours arising from the interstitial tissue of the brain which are heterogeneous, infiltrative and possess ill-defined borders. Tumour subregions (e.g. solid enhancing part, edema and necrosis) are often used for tumour characterisation. Tumour demarcation into substructures facilitates glioma staging and provides essential information. Manual segmentation had several drawbacks that include laborious, time consuming, subjected to intra and inter-rater variability and hindered by diversity in the appearance of tumour tissues. In this work, active contour model (ACM) was used to segment the solid enhancing subregion of the tumour. 2D brain image acquisition data using 3T MRI fast spoiled gradient echo sequence in post gadolinium of four histologically proven high-grade glioma patients were obtained. Preprocessing of the images which includes subtraction and skull stripping were performed and then followed by ACM segmentation. The results of the automatic segmentation method were compared against the manual delineation of the tumour by a trainee radiologist. Both results were further validated by an experienced neuroradiologist and a brief quantitative evaluations (pixel area and difference ratio) were performed. Preliminary results of the clinical data showed the potential of ACM model in the application of fast and large scale tumour segmentation in medical imaging. (paper)

  2. A five-colour colour-coded mapping method for DCE-MRI analysis of head and neck tumours

    International Nuclear Information System (INIS)

    Yuan, J.; Chow, S.K.K.; Yeung, D.K.W.; King, A.D.

    2012-01-01

    Aim: To devise a method to convert the time–intensity curves (TICs) of head and neck dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data into a pixel-by-pixel colour-coded map for identifying normal tissues and tumours. Materials and methods: Twenty-three patients with head and neck squamous cell carcinoma (HNSCC) underwent DCE-MRI. TIC patterns of primary tumours, metastatic nodes, and normal tissues were assessed and a program was devised to convert the patterns into a classified colour-coded map. The enhancement patterns of tumours and normal tissue structures were evaluated and categorized into nine grades (0–8) based on the predominance of coloured pixels on maps. Results: Five identified TIC patterns were converted into a colour-coded map consisting of red (maximum enhancement), brown (continuous slow rise-up), yellow (rapid wash-in and wash-out), green (rapid wash-in and plateau), and blue (rapid wash-in and rise-up). The colour-coded map distinguished all 21 primary tumours and 15 metastatic nodes from normal structures. Primary tumours and metastatic nodes were colour coded as predominantly yellow (grades 1–2) in 17/21 and 6/15, green (grades 3–5) in 3/21 and 5/15, and blue (grades 6–7) in 1/21 and 4/15, respectively. Vessels were coded red in 46/46 (grade 0) and muscles were coded brown in 23/23 (grade 8). Salivary glands, thyroid glands, and palatine tonsils were coded into predominantly yellow (grade 1) in 46/46 and 10/10 and 18/22, respectively. Conclusion: DCE-MRI derived five-colour-coded mapping provides an objective easy-to-interpret method to assess the dynamic enhancement pattern of head and neck cancers.

  3. Development and Validation of MRI Sacroiliac Joint Scoring Methods for the Semiaxial Scan Plane Corresponding to the Berlin and SPARCC MRI Scoring Methods, and of a New Global MRI Sacroiliac Joint Method

    DEFF Research Database (Denmark)

    Hededal, Pernille; Østergaard, Mikkel; Sørensen, Inge Juul

    2018-01-01

    OBJECTIVE: To develop semiaxial magnetic resonance imaging (MRI) scoring methods for assessment of sacroiliac joint (SIJ) bone marrow edema (BME) in patients with axial spondyloarthritis, and to compare the reliability with equivalent semicoronal scoring methods. METHODS: Two semiaxial SIJ MRI sc...

  4. Measurement of normal corpus callosum with MRI in Korean adults and morphological change of corpus callosum by grade of hydrocephalus

    International Nuclear Information System (INIS)

    Song, Dong Hoon; Chang, Seung Kuk; Kim, Jong Deok; Eun, Tchoong Kie; Park, Dong Woo

    1995-01-01

    To measure the size of normal corpus callosum in each portion using objective and reproducible method with MRI and evaluation of morphological change of corpus callosum by grade of hydrocephalus. Midsagittal T1-weighted MR imaging of the corpus callosum was investigated in 41 volunteers of normal Korean adults and 19 patients with hydrocephalus. Corpus callosum was measured for the anteroposterior length(A), height(B), and the thickness of genu(C), body(D), splenium(E), and the narrowest portion of body(F). And the analysis of morphology and signal intensity of the corpus callosum were also evaluated. Hydrocephalus was graded as mild, moderate, and severe, and comparison of thickness with normal corpus callosum in each portion was done. The mean length and height were 72.3 mm, 28.6 mm in male, and 70.7 mm, 28.9 mm in female. And the mean dimension for C, D, E and F were 13.1 mm, 8 mm, 13.2 mm, 5.2 mm in male, and 12.8 mm, 7.5 mm, 12.3 mm, 5 mm in female. The morphology of normal corpus callosum was 'hook' shaped on midline sagittal T1-weighted image. Narrowing at posterior third portion of body were present on 30 cases(73.2%) and even in thickness of the body in 11 cases(26.8%). The signal intensity of the corpus callosum on midsagittal T1-weighted spin echo image of normal cases was homogeneous hyperintense as compared with cerebral gray matter. In hydrocephalus, A and B were increased and other portions were decreased in thickness. Genu and the narrowest portion of body showed significant difference of thickness according to the grade of hydrocephalus. The mean dimension of all portion of corpus callosum were larger in male than female except for callosal height but not significant statistically with the exception of splenium. Hydrocephalus lead to morphological change of the corpus callosum. Among the portion of corpus callosum, genu and the narrowest portion of the body were thought to be the most sensitive indicators of degree in hydrocephalus

  5. Textural features of dynamic contrast-enhanced MRI derived model-free and model-based parameter maps in glioma grading.

    Science.gov (United States)

    Xie, Tian; Chen, Xiao; Fang, Jingqin; Kang, Houyi; Xue, Wei; Tong, Haipeng; Cao, Peng; Wang, Sumei; Yang, Yizeng; Zhang, Weiguo

    2018-04-01

    Presurgical glioma grading by dynamic contrast-enhanced MRI (DCE-MRI) has unresolved issues. The aim of this study was to investigate the ability of textural features derived from pharmacokinetic model-based or model-free parameter maps of DCE-MRI in discriminating between different grades of gliomas, and their correlation with pathological index. Retrospective. Forty-two adults with brain gliomas. 3.0T, including conventional anatomic sequences and DCE-MRI sequences (variable flip angle T1-weighted imaging and three-dimensional gradient echo volumetric imaging). Regions of interest on the cross-sectional images with maximal tumor lesion. Five commonly used textural features, including Energy, Entropy, Inertia, Correlation, and Inverse Difference Moment (IDM), were generated. All textural features of model-free parameters (initial area under curve [IAUC], maximal signal intensity [Max SI], maximal up-slope [Max Slope]) could effectively differentiate between grade II (n = 15), grade III (n = 13), and grade IV (n = 14) gliomas (P textural features, Entropy and IDM, of four DCE-MRI parameters, including Max SI, Max Slope (model-free parameters), vp (Extended Tofts), and vp (Patlak) could differentiate grade III and IV gliomas (P textural features of any DCE-MRI parameter maps could discriminate between subtypes of grade II and III gliomas (P features revealed relatively lower inter-observer agreement. No significant correlation was found between microvascular density and textural features, compared with a moderate correlation found between cellular proliferation index and those features. Textural features of DCE-MRI parameter maps displayed a good ability in glioma grading. 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1099-1111. © 2017 International Society for Magnetic Resonance in Medicine.

  6. Method of dry distillation of low-grade fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hellsing, G H; Wengstrom, R O.A.

    1920-05-20

    A method of dry distillation of low-grade fuels is characterized by having the process take place in a furnace that is charged alternately by partly cooled, red-hot, and fresh raw materials. The patent has one more claim.

  7. MRI

    DEFF Research Database (Denmark)

    Schroeter, Aileen; Rudin, Markus; Gianolio, Eliana

    2017-01-01

    This chapter discusses principles of nuclear magnetic resonance (NMR) and MRI followed by a survey on the major classes of MRI contrast agents (CA), their modes of action, and some of the most significative applications. The two more established classes of MRI-CA are represented by paramagnetic...... been attained that markedly increase the number and typology of systems with CEST properties. Currently much attention is also devoted to hyperpolarized molecules that display a sensitivity enhancement sufficient for their direct exploitation for the formation of the MR image. A real breakthrough...

  8. MRI

    Science.gov (United States)

    ... the room. Pins, hairpins, metal zippers, and similar metallic items can distort the images. Removable dental work ... an MRI can cause heart pacemakers and other implants not to work as well. The magnets can ...

  9. Reorganization of Language Areas in Patient with a Frontal Lobe Low Grade Glioma – fMRI Case Study

    International Nuclear Information System (INIS)

    Kośla, Katarzyna; Bryszewski, Bartosz; Jaskólski, Dariusz; Błasiak-Kołacińska, Nina; Stefańczyk, Ludomir; Majos, Agata

    2015-01-01

    Functional magnetic resonance (fMRI) studies results in case of an adult patient with low grade glioma (LGG) in dominant hemisphere suggest brain plasticity process with acquisition of language functions by the non-dominant hemisphere speech regions. A 36-years old right-handed woman was admitted to the Department of Neurosurgery for surgical treatment of brain tumor. An MRI examination revealed a pathological mass in the left frontal lobe, in close topographical relationship to the Broca’s area. A left fronto-parietal craniotomy was performed, with an intraoperative awake language mapping procedure. A total resection of the pathological mass was achieved. The tumor was examined histologically as LGG. In the follow-up MRI exam 32 months after the operation a tumor recurrence was suggested. The fMRI exams performed preoperative and 3, 32 and 41 months after the operation showed changes in language regions activation patterns, with a progressive right-sided activation of Broca’s and Wernicke’s areas. Pre- and postoperative cognitive evaluation by a neuropsychologist did not detect any language impairment. We present a running process of reorganization of language areas in a patient after brain tumor resection, from strong left-sided to symmetrical lateralization. 1. FMRI results in comparison with the psychological status of the patient proved contribution of functional reorganization to the preservation of language performance. 2. A slow growing LGG as well as the recurrence of the tumor near the left Broca’s area might be the factors leading to reorganization of language-related areas by recruiting the right hemisphe

  10. Prognostic value of preoperative dynamic contrast-enhanced MRI perfusion parameters for high-grade glioma patients

    Energy Technology Data Exchange (ETDEWEB)

    Ulyte, Agne [Vilnius University, Faculty of Medicine, Vilnius (Lithuania); Katsaros, Vasileios K. [General Anticancer and Oncological Hospital ' ' St. Savvas' ' , Department of Advanced Imaging Modalities - CT and MRI, Athens (Greece); University of Athens, Department of Neurosurgery, Evangelismos Hospital, Athens (Greece); Liouta, Evangelia; Stranjalis, Georgios [University of Athens, Department of Neurosurgery, Evangelismos Hospital, Athens (Greece); Boskos, Christos [University of Athens, Department of Neurosurgery, Evangelismos Hospital, Athens (Greece); General Anticancer and Oncological Hospital ' ' St. Savvas' ' , Department of Radiation Oncology, Athens (Greece); Papanikolaou, Nickolas [Champalimaud Foundation, Department of Radiology, Centre for the Unknown, Lisbon (Portugal); Usinskiene, Jurgita [National Cancer Institute, Vilnius (Lithuania); Affidea Lietuva, Vilnius (Lithuania); Bisdas, Sotirios [University College London Hospitals, Department of Neuroradiology, The National Hospital for Neurology and Neurosurgery, London (United Kingdom)

    2016-12-15

    The prognostic value of the dynamic contrast-enhanced (DCE) MRI perfusion and its histogram analysis-derived metrics is not well established for high-grade glioma (HGG) patients. The aim of this prospective study was to investigate DCE perfusion transfer coefficient (K{sup trans}), vascular plasma volume fraction (v{sub p}), extracellular volume fraction (v{sub e}), reverse transfer constant (k{sub ep}), and initial area under gadolinium concentration time curve (IAUGC) as predictors of progression-free (PFS) and overall survival (OS) in HGG patients. Sixty-nine patients with suspected anaplastic astrocytoma or glioblastoma underwent preoperative DCE-MRI scans. DCE perfusion whole tumor region histogram parameters, clinical details, and PFS and OS data were obtained. Univariate, multivariate, and Kaplan-Meier survival analyses were conducted. Receiver operating characteristic (ROC) curve analysis was employed to identify perfusion parameters with the best differentiation performance. On univariate analysis, v{sub e} and skewness of v{sub p} had significant negative impacts, while k{sub ep} had significant positive impact on OS (P < 0.05). v{sub e} was also a negative predictor of PFS (P < 0.05). Patients with lower v{sub e} and IAUGC had longer median PFS and OS on Kaplan-Meier analysis (P < 0.05). K{sup trans} and v{sub e} could also differentiate grade III from IV gliomas (area under the curve 0.819 and 0.791, respectively). High v{sub e} is a consistent predictor of worse PFS and OS in HGG glioma patients. v{sub p} skewness and k{sub ep} are also predictive for OS. K{sup trans} and v{sub e} demonstrated the best diagnostic performance for differentiating grade III from IV gliomas. (orig.)

  11. [Fusion of MRI, fMRI and intraoperative MRI data. Methods and clinical significance exemplified by neurosurgical interventions].

    Science.gov (United States)

    Moche, M; Busse, H; Dannenberg, C; Schulz, T; Schmitgen, A; Trantakis, C; Winkler, D; Schmidt, F; Kahn, T

    2001-11-01

    The aim of this work was to realize and clinically evaluate an image fusion platform for the integration of preoperative MRI and fMRI data into the intraoperative images of an interventional MRI system with a focus on neurosurgical procedures. A vertically open 0.5 T MRI scanner was equipped with a dedicated navigation system enabling the registration of additional imaging modalities (MRI, fMRI, CT) with the intraoperatively acquired data sets. These merged image data served as the basis for interventional planning and multimodal navigation. So far, the system has been used in 70 neurosurgical interventions (13 of which involved image data fusion--requiring 15 minutes extra time). The augmented navigation system is characterized by a higher frame rate and a higher image quality as compared to the system-integrated navigation based on continuously acquired (near) real time images. Patient movement and tissue shifts can be immediately detected by monitoring the morphological differences between both navigation scenes. The multimodal image fusion allowed a refined navigation planning especially for the resection of deeply seated brain lesions or pathologies close to eloquent areas. Augmented intraoperative orientation and instrument guidance improve the safety and accuracy of neurosurgical interventions.

  12. [MRI methods for pulmonary ventilation and perfusion imaging].

    Science.gov (United States)

    Sommer, G; Bauman, G

    2016-02-01

    Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O2-enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies.

  13. MRI methods for pulmonary ventilation and perfusion imaging

    International Nuclear Information System (INIS)

    Sommer, G.; Bauman, G.

    2016-01-01

    Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O 2 -enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies. (orig.) [de

  14. IDH mutant and 1p/19q co-deleted oligodendrogliomas: tumor grade stratification using diffusion-, susceptibility-, and perfusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yu; Xing, Zhen; She, Dejun; Yang, Xiefeng; Zheng, Yingyan; Xiao, Zebin; Cao, Dairong [First Affiliated Hospital of Fujian Medical University, Department of Radiology, Fuzhou, Fujian (China); Wang, Xingfu [First Affiliated Hospital of Fujian Medical University, Department of Pathology, Fuzhou (China)

    2017-06-15

    Currently, isocitrate dehydrogenase (IDH) mutation and 1p/19q co-deletion are proven diagnostic biomarkers for both grade II and III oligodendrogliomas (ODs). Non-invasive diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI), and dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) are widely used to provide physiological information (cellularity, hemorrhage, calcifications, and angiogenesis) of neoplastic histology and tumor grade. However, it is unclear whether DWI, SWI, and DSC-PWI are able to stratify grades of IDH-mutant and 1p/19q co-deleted ODs. We retrospectively reviewed the conventional MRI (cMRI), DWI, SWI, and DSC-PWI obtained on 33 patients with IDH-mutated and 1p/19q co-deleted ODs. Features of cMRI, normalized ADC (nADC), intratumoral susceptibility signals (ITSSs), normalized maxim CBV (nCBV), and normalized maximum CBF (nCBF) were compared between low-grade ODs (LGOs) and high-grade ODs (HGOs). Receiver operating characteristic curve and logistic regression were applied to determine diagnostic performances. HGOs tended to present with prominent edema and enhancement. nADC, ITSSs, nCBV, and nCBF were significantly different between groups (all P < 0.05). The combination of SWI and DSC-PWI for grading resulted in sensitivity and specificity of 100.00 and 93.33%, respectively. IDH-mutant and 1p/19q co-deleted ODs can be stratified by grades using cMRI and advanced magnetic resonance imaging techniques including DWI, SWI, and DSC-PWI. Combined ITSSs with nCBV appear to be a promising option for grading molecularly defined ODs in clinical practice. (orig.)

  15. Determination of vanadium in high grade carbons by radioanalytical methods

    International Nuclear Information System (INIS)

    Jinno, K.; Sato, M.; Amemiya, S.; Katoh, T.

    1980-01-01

    The present work deals with the determination of vanadium in high grade carbons by three radioanalytical methods, viz. thermal neutron activation analysis with an accelerator, thermal neutron activation analysis with a reactor and proton induced X-ray emission analysis with an accelerator. It is shown that thermal neutron activation with an accelerator is more convenient for the rapid and non-destructive analysis of ppm-level vanadium in bulk carbons than thermal neutron activation analysis with a reactor. Proton-induced X-ray emission is less useful for the analysis of bulk samples. (author)

  16. Diagnostic value of MRI-based 3D texture analysis for tissue characterisation and discrimination of low-grade chondrosarcoma from enchondroma. A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Lisson, Catharina S.; Lisson, Christoph G.; Flosdorf, Kerstin; Meier, Reinhard; Beer, Meinrad; Schmidt, Stefan A. [University Hospital of Ulm, Department of Diagnostic and Interventional Radiology, Ulm (Germany); Mayer-Steinacker, Regine [University Hospital of Ulm, Department of Internal Medicine III, Ulm (Germany); Schultheiss, Markus; Baer, Alexandra von [University Hospital of Ulm, Department of Trauma Surgery, Ulm (Germany); Barth, Thomas F.E. [University of Ulm, Institute of Pathology, Ulm (Germany); Beer, Ambros J. [University Hospital of Ulm, Department of Nuclear Medicine, Ulm (Germany); Baumhauer, Matthias [Mint Medical, Dossenheim (Germany)

    2018-02-15

    To explore the diagnostic value of MRI-based 3D texture analysis to identify texture features that can be used for discrimination of low-grade chondrosarcoma from enchondroma. Eleven patients with low-grade chondrosarcoma and 11 patients with enchondroma were retrospectively evaluated. Texture analysis was performed using mint Lesion: Kurtosis, entropy, skewness, mean of positive pixels (MPP) and uniformity of positive pixel distribution (UPP) were obtained in four MRI sequences and correlated with histopathology. The Mann-Whitney U-test and receiver operating characteristic (ROC) analysis were performed to identify most discriminative texture features. Sensitivity, specificity, accuracy and optimal cut-off values were calculated. Significant differences were found in four of 20 texture parameters with regard to the different MRI sequences (p<0.01). The area under the ROC curve values to discriminate chondrosarcoma from enchondroma were 0.876 and 0.826 for kurtosis and skewness in contrast-enhanced T1 (ceT1w), respectively; in non-contrast T1, values were 0.851 and 0.822 for entropy and UPP, respectively. The highest discriminatory power had kurtosis in ceT1w with a cut-off ≥3.15 to identify low-grade chondrosarcoma (82 % sensitivity, 91 % specificity, accuracy 86 %). MRI-based 3D texture analysis might be able to discriminate low-grade chondrosarcoma from enchondroma by a variety of texture parameters. (orig.)

  17. Method and apparatus for producing food grade carbon dioxide

    International Nuclear Information System (INIS)

    Nobles, J.E.; Swenson, L.K.

    1984-01-01

    A method is disclosed of producing food grade carbon dioxide from an impure carbon dioxide source stream containing contaminants which may include light and heavy hydrocarbons (at least C 1 to C 3 ) and light sulfur compounds such as hydrogen sulfide and carbonyl sulfide as well as heavier sulfur constituents in the nature of mercaptans (RSH) and/or organic mono and disulfides (RSR and RSSR). Nitrogen, water and/or oxygen may also be present in varying amounts in the impure feed stream. The feed gas is first rectified with liquid carbon dioxide condensed from a part of the feed stream to remove heavy hydrocarbons and heavy sulfur compounds, then passed through an absorber to effect removal of the light sulfur compounds, next subjected to an oxidizing atmosphere capable of converting all of the C 2 hydrocarbons and optionally a part of the methane to carbon oxides and water, chilled to condense the water in the remaining gas stream without formation of hydrates, liquefied for ease of handling and storage and finally stripped to remove residual contaminants such as methane, carbon monoxide and nitrogen to produce the final food grade carbon dioxide product

  18. Development of fracture toughness test method for nuclear grade graphite

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C. H.; Lee, J. S.; Cho, H. C.; Kim, D. J.; Lee, D. J. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2006-02-15

    Because of its high strength and stability at very high temperature, as well as very low thermal neutron absorption cross-section, graphite has been widely used as a structural material in Gas Cooled Reactors (GCR). Recently, many countries are developing the Very High Temperature gas cooled Reactor (VHTR) because of the potentials of hydrogen production, as well as its safety and viable economics. In VHTR, helium gas serves as the primary coolant. Graphite will be used as a reflector, moderator and core structural materials. The life time of graphite is determined from dimensional changes due to neutron irradiation, which closely relates to the changes of crystal structure. The changes of both lattice parameter and crystallite size can be easily measured by X-ray diffraction method. However, due to high cost and long time of neutron irradiation test, ion irradiation test is being performed instead in KAERI. Therefore, it is essential to develop the technique for measurement of ion irradiation damage of nuclear graphite. Fracture toughness of nuclear grade graphite is one of the key properties in the design and development of VHTR. It is important not only to evaluate the various properties of candidate graphite but also to assess the integrity of nuclear grade graphite during operation. Although fracture toughness tests on graphite have been performed in many laboratories, there have been wide variations in values of the calculated fracture toughness, due to the differences in the geometry of specimens and test conditions. Hence, standard test method for nuclear graphite is required to obtain the reliable fracture toughness values. Crack growth behavior of nuclear grade graphite shows rising R-curve which means the increase in crack growth resistance as the crack length increases. Crack bridging and microcracking have been proposed to be the dominant mechanisms of rising R-curve behavior. In this paper, the technique to measure the changes of crystallite size and

  19. Survey VS audit by using method 2 to dedicate commercial grade services

    International Nuclear Information System (INIS)

    Martinez ayucar, F. J.

    2014-01-01

    Since the start of the commercial grade dedications, both 10CFR21 and EPRI documents, plus the dedication of commercial grade components, and the stage of commercial grade dedication of the services contemplated. And recently the NRC through various communications and answers trafficking among other issues the commercial grade dedication service. The NRC has detected repeatedly incorrect application of the survey as a method of commercial grade dedication and instead has done an audit of the program elements of commercial quality. (Author)

  20. A Pilot Comparative Study of Quantitative Ultrasound, Conventional Ultrasound, and MRI for Predicting Histology-Determined Steatosis Grade in Adult Nonalcoholic Fatty Liver Disease.

    Science.gov (United States)

    Paige, Jeremy S; Bernstein, Gregory S; Heba, Elhamy; Costa, Eduardo A C; Fereirra, Marilia; Wolfson, Tanya; Gamst, Anthony C; Valasek, Mark A; Lin, Grace Y; Han, Aiguo; Erdman, John W; O'Brien, William D; Andre, Michael P; Loomba, Rohit; Sirlin, Claude B

    2017-05-01

    The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD). In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014. Subjects underwent QUS, CUS, and MRI examinations within 100 days of clinical-care liver biopsy. QUS parameters (attenuation coefficient and backscatter coefficient) were estimated using a reference phantom technique by two analysts independently. Three-point ordinal CUS scores intended to predict steatosis grade (1, 2, or 3) were generated independently by two radiologists on the basis of QUS features. PDFF was estimated using an advanced chemical shift-based MRI technique. Using histologic examination as the reference standard, ROC analysis was performed. Optimal attenuation coefficient, backscatter coefficient, and PDFF cutoff thresholds were identified, and the accuracy of attenuation coefficient, backscatter coefficient, PDFF, and CUS to predict steatosis grade was determined. Interobserver agreement for attenuation coefficient, backscatter coefficient, and CUS was analyzed. CUS had 51.7% grading accuracy. The raw and cross-validated steatosis grading accuracies were 61.7% and 55.0%, respectively, for attenuation coefficient, 68.3% and 68.3% for backscatter coefficient, and 76.7% and 71.3% for MRI-estimated PDFF. Interobserver agreements were 53.3% for CUS (κ = 0.61), 90.0% for attenuation coefficient (κ = 0.87), and 71.7% for backscatter coefficient (κ = 0.82) (p hepatic steatosis grade in patients with NAFLD.

  1. Differential quadrature method of nonlinear bending of functionally graded beam

    Science.gov (United States)

    Gangnian, Xu; Liansheng, Ma; Wang, Youzhi; Quan, Yuan; Weijie, You

    2018-02-01

    Using the third-order shear deflection beam theory (TBT), nonlinear bending of functionally graded (FG) beams composed with various amounts of ceramic and metal is analyzed utilizing the differential quadrature method (DQM). The properties of beam material are supposed to accord with the power law index along to thickness. First, according to the principle of stationary potential energy, the partial differential control formulae of the FG beams subjected to a distributed lateral force are derived. To obtain numerical results of the nonlinear bending, non-dimensional boundary conditions and control formulae are dispersed by applying the DQM. To verify the present solution, several examples are analyzed for nonlinear bending of homogeneous beams with various edges. A minute parametric research is in progress about the effect of the law index, transverse shear deformation, distributed lateral force and boundary conditions.

  2. Numerical modeling of isothermal compositional grading by convex splitting methods

    KAUST Repository

    Li, Yiteng

    2017-04-09

    In this paper, an isothermal compositional grading process is simulated based on convex splitting methods with the Peng-Robinson equation of state. We first present a new form of gravity/chemical equilibrium condition by minimizing the total energy which consists of Helmholtz free energy and gravitational potential energy, and incorporating Lagrange multipliers for mass conservation. The time-independent equilibrium equations are transformed into a system of transient equations as our solution strategy. It is proved our time-marching scheme is unconditionally energy stable by the semi-implicit convex splitting method in which the convex part of Helmholtz free energy and its derivative are treated implicitly and the concave parts are treated explicitly. With relaxation factor controlling Newton iteration, our method is able to converge to a solution with satisfactory accuracy if a good initial estimate of mole compositions is provided. More importantly, it helps us automatically split the unstable single phase into two phases, determine the existence of gas-oil contact (GOC) and locate its position if GOC does exist. A number of numerical examples are presented to show the performance of our method.

  3. Correlation of diffusion and perfusion MRI with Ki-67 in high-grade meningiomas.

    Science.gov (United States)

    Ginat, Daniel T; Mangla, Rajiv; Yeaney, Gabrielle; Wang, Henry Z

    2010-12-01

    Atypical and anaplastic meningiomas have a greater likelihood of recurrence than benign meningiomas. The risk for recurrence is often estimated using the Ki-67 labeling index. The purpose of this study was to determine the correlation between Ki-67 and regional cerebral blood volume (rCBV) and between Ki-67 and apparent diffusion coefficient (ADC) in atypical and anaplastic meningiomas. A retrospective review of the advanced imaging and immunohistochemical characteristics of atypical and anaplastic meningiomas was performed. The relative minimum ADC, relative maximum rCBV, and specimen Ki-67 index were measured. Pearson's correlation was used to compare these parameters. There were 23 cases with available ADC maps and 20 cases with available rCBV maps. The average Ki-67 among the cases with ADC maps and rCBV maps was 17.6% (range, 5-38%) and 16.7% (range, 3-38%), respectively. The mean minimum ADC ratio was 0.91 (SD, 0.26) and the mean maximum rCBV ratio was 22.5 (SD, 7.9). There was a significant positive correlation between maximum rCBV and Ki-67 (Pearson's correlation, 0.69; p = 0.00038). However, there was no significant correlation between minimum ADC and Ki-67 (Pearson's correlation, -0.051; p = 0.70). Maximum rCBV correlated significantly with Ki-67 in high-grade meningiomas.

  4. A comparison of exogenous and endogenous CEST MRI methods for evaluating in vivo pH.

    Science.gov (United States)

    Lindeman, Leila R; Randtke, Edward A; High, Rachel A; Jones, Kyle M; Howison, Christine M; Pagel, Mark D

    2018-05-01

    Extracellular pH (pHe) is an important biomarker for cancer cell metabolism. Acido-chemical exchange saturation transfer (CEST) MRI uses the contrast agent iopamidol to create spatial maps of pHe. Measurements of amide proton transfer exchange rates (k ex ) from endogenous CEST MRI were compared to pHe measurements by exogenous acido-CEST MRI to determine whether endogenous k ex could be used as a proxy for pHe measurements. Spatial maps of pHe and k ex were obtained using exogenous acidoCEST MRI and an endogenous CEST MRI analyzed with the omega plot method, respectively, to evaluate mouse kidney, a flank tumor model, and a spontaneous lung tumor model. The pHe and k ex results were evaluated using pixelwise comparisons. The k ex values obtained from endogenous CEST measurements did not correlate with the pHe results from exogenous CEST measurements. The k ex measurements were limited to fewer pixels and had a limited dynamic range relative to pHe measurements. Measurements of k ex with endogenous CEST MRI cannot substitute for pHe measurements with acidoCEST MRI. Whereas endogenous CEST MRI may still have good utility for evaluating some specific pathologies, exogenous acido-CEST MRI is more appropriate when evaluating pathologies based on pHe values. Magn Reson Med 79:2766-2772, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  5. MRI to determine the chronological age of Ghanaian footballers

    African Journals Online (AJOL)

    of fusion of the distal radius on magentic resonance imaging (MRI) and comparing it with the Fédération Internationale de Football. Association (FIFA) MRI grading. Methods. MRI scans of the left wrists of 86 players aspiring to play for the national U17 football team were recruited for the study during a. 'justify your inclusion ...

  6. EEG-Informed fMRI: A Review of Data Analysis Methods

    Science.gov (United States)

    Abreu, Rodolfo; Leal, Alberto; Figueiredo, Patrícia

    2018-01-01

    The simultaneous acquisition of electroencephalography (EEG) with functional magnetic resonance imaging (fMRI) is a very promising non-invasive technique for the study of human brain function. Despite continuous improvements, it remains a challenging technique, and a standard methodology for data analysis is yet to be established. Here we review the methodologies that are currently available to address the challenges at each step of the data analysis pipeline. We start by surveying methods for pre-processing both EEG and fMRI data. On the EEG side, we focus on the correction for several MR-induced artifacts, particularly the gradient and pulse artifacts, as well as other sources of EEG artifacts. On the fMRI side, we consider image artifacts induced by the presence of EEG hardware inside the MR scanner, and the contamination of the fMRI signal by physiological noise of non-neuronal origin, including a review of several approaches to model and remove it. We then provide an overview of the approaches specifically employed for the integration of EEG and fMRI when using EEG to predict the blood oxygenation level dependent (BOLD) fMRI signal, the so-called EEG-informed fMRI integration strategy, the most commonly used strategy in EEG-fMRI research. Finally, we systematically review methods used for the extraction of EEG features reflecting neuronal phenomena of interest. PMID:29467634

  7. EEG-Informed fMRI: A Review of Data Analysis Methods

    Directory of Open Access Journals (Sweden)

    Rodolfo Abreu

    2018-02-01

    Full Text Available The simultaneous acquisition of electroencephalography (EEG with functional magnetic resonance imaging (fMRI is a very promising non-invasive technique for the study of human brain function. Despite continuous improvements, it remains a challenging technique, and a standard methodology for data analysis is yet to be established. Here we review the methodologies that are currently available to address the challenges at each step of the data analysis pipeline. We start by surveying methods for pre-processing both EEG and fMRI data. On the EEG side, we focus on the correction for several MR-induced artifacts, particularly the gradient and pulse artifacts, as well as other sources of EEG artifacts. On the fMRI side, we consider image artifacts induced by the presence of EEG hardware inside the MR scanner, and the contamination of the fMRI signal by physiological noise of non-neuronal origin, including a review of several approaches to model and remove it. We then provide an overview of the approaches specifically employed for the integration of EEG and fMRI when using EEG to predict the blood oxygenation level dependent (BOLD fMRI signal, the so-called EEG-informed fMRI integration strategy, the most commonly used strategy in EEG-fMRI research. Finally, we systematically review methods used for the extraction of EEG features reflecting neuronal phenomena of interest.

  8. An Introduction to Normalization and Calibration Methods in Functional MRI

    Science.gov (United States)

    Liu, Thomas T.; Glover, Gary H.; Mueller, Bryon A.; Greve, Douglas N.; Brown, Gregory G.

    2013-01-01

    In functional magnetic resonance imaging (fMRI), the blood oxygenation level dependent (BOLD) signal is often interpreted as a measure of neural activity. However, because the BOLD signal reflects the complex interplay of neural, vascular, and metabolic processes, such an interpretation is not always valid. There is growing evidence that changes…

  9. An iterative reconstruction method of complex images using expectation maximization for radial parallel MRI

    International Nuclear Information System (INIS)

    Choi, Joonsung; Kim, Dongchan; Oh, Changhyun; Han, Yeji; Park, HyunWook

    2013-01-01

    In MRI (magnetic resonance imaging), signal sampling along a radial k-space trajectory is preferred in certain applications due to its distinct advantages such as robustness to motion, and the radial sampling can be beneficial for reconstruction algorithms such as parallel MRI (pMRI) due to the incoherency. For radial MRI, the image is usually reconstructed from projection data using analytic methods such as filtered back-projection or Fourier reconstruction after gridding. However, the quality of the reconstructed image from these analytic methods can be degraded when the number of acquired projection views is insufficient. In this paper, we propose a novel reconstruction method based on the expectation maximization (EM) method, where the EM algorithm is remodeled for MRI so that complex images can be reconstructed. Then, to optimize the proposed method for radial pMRI, a reconstruction method that uses coil sensitivity information of multichannel RF coils is formulated. Experiment results from synthetic and in vivo data show that the proposed method introduces better reconstructed images than the analytic methods, even from highly subsampled data, and provides monotonic convergence properties compared to the conjugate gradient based reconstruction method. (paper)

  10. Integration of BOLD-fMRI and DTI into radiation treatment planning for high-grade gliomas located near the primary motor cortexes and corticospinal tracts

    International Nuclear Information System (INIS)

    Wang, Minglei; Ma, Hui; Wang, Xiaodong; Guo, Yanhong; Xia, Xinshe; Xia, Hechun; Guo, Yulin; Huang, Xueying; He, Hong; Jia, Xiaoxiong; Xie, Yan

    2015-01-01

    The main objective of this study was to evaluate the efficacy of integrating the blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) and diffusion tensor imaging (DTI) data into radiation treatment planning for high-grade gliomas located near the primary motor cortexes (PMCs) and corticospinal tracts (CSTs). A total of 20 patients with high-grade gliomas adjacent to PMCs and CSTs between 2012 and 2014 were recruited. The bilateral PMCs and CSTs were located in the normal regions without any overlapping with target volume of the lesions. BOLD-fMRI, DTI and conventional MRI were performed on patients (Karnofsky performance score ≥ 70) before radical radiotherapy treatment. Four different imaging studies were conducted in each patient: a planning computed tomography (CT), an anatomical MRI, a DTI and a BOLD-fMRI. For each case, three treatment plans (3DCRT, IMRT and IMRT-PMC&CST) were developed by 3 different physicists using the Pinnacle planning system. Our study has shown that there was no significant difference between the 3DCRT and IMRT plans in terms of dose homogeneity, but IMRT displayed better planning target volume (PTV) dose conformity. In addition, we have found that the Dmax and Dmean to the ipsilateral and contralateral PMC and CST regions were considerably decreased in IMRT-PMC&CST group (p < 0.001). In conclusion, integration of BOLD-fMRI and DTI into radiation treatment planning is feasible and beneficial. With the assistance of the above-described techniques, the bilateral PMCs and CSTs adjacent to the target volume could be clearly marked as OARs and spared during treatment

  11. Interobserver agreement of radiologists assessing the response of rectal cancers to preoperative chemoradiation using the MRI tumour regression grading (mrTRG)

    International Nuclear Information System (INIS)

    Siddiqui, M.R.S.; Gormly, K.L.; Bhoday, J.; Balyansikova, S.; Battersby, N.J.; Chand, M.; Rao, S.; Tekkis, P.; Abulafi, A.M.; Brown, G.

    2016-01-01

    Aim: To investigate whether the magnetic resonance imaging (MRI) tumour regression grading (mrTRG) scale can be taught effectively resulting in a clinically reasonable interobserver agreement (>0.4; moderate to near perfect agreement). Materials and methods: This study examines the interobserver agreement of mrTRG, between 35 radiologists and a central reviewer. Two workshops were organised for radiologists to assess regression of rectal cancers on MRI staging scans. A range of mrTRGs on 12 patient scans were used for assessment. Results: Kappa agreement ranged from 0.14–0.82 with a median value of 0.57 (95% CI: 0.37–0.77) indicating good overall agreement. Eight (26%) radiologists had very good/near perfect agreement (κ>0.8). Six (19%) radiologists had good agreement (0.8≥κ>0.6) and a further 12 (39%) had moderate agreement (0.6≥κ>0.4). Five (16%) radiologists had a fair agreement (0.4≥κ>0.2) and two had poor agreement (0.2>κ). There was a tendency towards good agreement (skewness: 0.92). In 65.9% and 90% of cases the radiologists were able to correctly highlight good and poor responders, respectively. Conclusions: The assessment of the response of rectal cancers to chemoradiation therapy may be performed effectively using mrTRG. Radiologists can be taught the mrTRG scale. Even with minimal training, good agreement with the central reviewer along with effective differentiation between good and intermediate/poor responders can be achieved. Focus should be on facilitating the identification of good responders. It is predicted that with more intensive interactive case-based learning a κ>0.8 is likely to be achieved. Testing and retesting is recommended. - Highlights: • Inter-observer agreement of radiologists was assessed using MRI rectal tumour regression scale. • Kappa agreement had a median value of 0.57 (95% CI: 0.37–0.77) indicating an overall good agreement. • In 65.9% and 90% of cases the radiologists were able to correctly highlight

  12. [Mechanical Shimming Method and Implementation for Permanent Magnet of MRI System].

    Science.gov (United States)

    Xue, Tingqiang; Chen, Jinjun

    2015-03-01

    A mechanical shimming method and device for permanent magnet of MRI system has been developed to meet its stringent homogeneity requirement without time-consuming passive shimming on site, installation and adjustment efficiency has been increased.

  13. Histological grade of differentiation of hepatocellular carcinoma: comparison of the efficacy of diffusion-weighted MRI with T2-weighted imaging and angiography-assisted CT

    International Nuclear Information System (INIS)

    Saito, Kazuhiro; Nishio, Ryota; Saguchi, Toru; Akata, Soichi; Tokuuye, Koichi; Moriyasu, Fuminori; Sugimoto, Katsutoshi

    2012-01-01

    The purpose of this study is to determine the usefulness of diffusion-weighted imaging (DWI) for evaluating the histological grade of differentiation of hepatocellular carcinoma (HCC) compared with T2-weighted imaging (T2WI) and tumour haemodynamics. We retrospectively evaluated 32 patients with 42 pathologically confirmed HCC nodules. These patients underwent MRI, CT during arterial portography and CT hepatic arteriography. We evaluated the relationship between the histological grade of differentiation and the apparent diffusion coefficient (ADC) values, conspicuity of tumour on DWI, DWI and T2WI contrast-to-noise (C/N) ratios and tumour haemodynamics. There was no correlation between the histological grade of differentiation and the ADC values. The DWI C/N ratio was significantly different among all histological grades, but the T2WI C/N ratio was not. Tumour conspicuity on DWI correlated well with the histological grade of differentiation, but tumour haemodynamics only partially correlated with the histological grade of differentiation. DWI was useful for evaluating the histological grade of differentiation of HCC.

  14. Principal Feature Analysis: A Multivariate Feature Selection Method for fMRI Data

    Directory of Open Access Journals (Sweden)

    Lijun Wang

    2013-01-01

    Full Text Available Brain decoding with functional magnetic resonance imaging (fMRI requires analysis of complex, multivariate data. Multivoxel pattern analysis (MVPA has been widely used in recent years. MVPA treats the activation of multiple voxels from fMRI data as a pattern and decodes brain states using pattern classification methods. Feature selection is a critical procedure of MVPA because it decides which features will be included in the classification analysis of fMRI data, thereby improving the performance of the classifier. Features can be selected by limiting the analysis to specific anatomical regions or by computing univariate (voxel-wise or multivariate statistics. However, these methods either discard some informative features or select features with redundant information. This paper introduces the principal feature analysis as a novel multivariate feature selection method for fMRI data processing. This multivariate approach aims to remove features with redundant information, thereby selecting fewer features, while retaining the most information.

  15. S-MRI score: A simple method for assessing bone marrow involvement in Gaucher disease

    International Nuclear Information System (INIS)

    Roca, M.; Mota, J.; Alfonso, P.; Pocovi, M.; Giraldo, P.

    2007-01-01

    Semi quantitative MRI is a very useful procedure for evaluating the bone marrow burden (BMB) in Gaucher disease (GD). Score systems have been applied to obtain a parameter for evaluating the severity of bone disease. Our purpose was to test a simple, reproducible and accurate score to evaluate bone marrow involvement in GD patients. MRI was performed in spine, pelvis and femora at diagnosis in 54 adult GD1 patients, 61.1% of whom were female. Three MRI patterns and punctuation in each location were defined: normal, 0; non-homogeneous infiltration subtypes reticular, 1; mottled, 2; diffuse, 3; and homogeneous infiltration, 4. This score was called Spanish-MRI (S-MRI). Two independent observers applied the S-MRI and bone marrow burden score and compared the differences using the non-parametric Mann-Whitney test. Correlation rank test was calculated. In 46 patients (85.2%), bone involvement was observed. Thirty-nine (72.3%) had their spine affected, 35 (64.8%) pelvis and 33 (61.2%) femora. Fourteen patients had bone infarcts, 14 avascular necrosis, 2 vertebral fractures and 2 bone crises. Correlation analysis between S-MRI and BMB was (r 2 = .675; p = .0001). No evidence of correlation was observed between CT activity and S-MRI nor between CT activity and BMB. We have found a relationship between genotype and bone infiltration according to S-MRI site and complications. S-MRI is a simple method that provides useful information to evaluate bone infiltration and detect silent complications. Our results correlated with the BMB score but offer higher sensitivity, specificity and accuracy for classifying the extent of bone disease

  16. S-MRI score: A simple method for assessing bone marrow involvement in Gaucher disease

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M. [Radiology (Magnetic Resonance) Instituto Aragones de Ciencias de la Salud (I-CS), Zaragoza (Spain); Mota, J. [Diagnostic Imaging Department, Medimagen, Barcelona (Spain); Alfonso, P. [Radiology (Magnetic Resonance) Instituto Aragones de Ciencias de la Salud (I-CS), Zaragoza (Spain); Pocovi, M. [Biochemistry and Cellular and Molecular Biology Department, Zaragoza University (Spain); Giraldo, P. [Haematology Department, Miguel Servet University Hospital, 50009 Zaragoza (Spain)]. E-mail: pgiraldo@salud.aragon.es

    2007-04-15

    Semi quantitative MRI is a very useful procedure for evaluating the bone marrow burden (BMB) in Gaucher disease (GD). Score systems have been applied to obtain a parameter for evaluating the severity of bone disease. Our purpose was to test a simple, reproducible and accurate score to evaluate bone marrow involvement in GD patients. MRI was performed in spine, pelvis and femora at diagnosis in 54 adult GD1 patients, 61.1% of whom were female. Three MRI patterns and punctuation in each location were defined: normal, 0; non-homogeneous infiltration subtypes reticular, 1; mottled, 2; diffuse, 3; and homogeneous infiltration, 4. This score was called Spanish-MRI (S-MRI). Two independent observers applied the S-MRI and bone marrow burden score and compared the differences using the non-parametric Mann-Whitney test. Correlation rank test was calculated. In 46 patients (85.2%), bone involvement was observed. Thirty-nine (72.3%) had their spine affected, 35 (64.8%) pelvis and 33 (61.2%) femora. Fourteen patients had bone infarcts, 14 avascular necrosis, 2 vertebral fractures and 2 bone crises. Correlation analysis between S-MRI and BMB was (r {sup 2} = .675; p = .0001). No evidence of correlation was observed between CT activity and S-MRI nor between CT activity and BMB. We have found a relationship between genotype and bone infiltration according to S-MRI site and complications. S-MRI is a simple method that provides useful information to evaluate bone infiltration and detect silent complications. Our results correlated with the BMB score but offer higher sensitivity, specificity and accuracy for classifying the extent of bone disease.

  17. A simple method for assigning genomic grade to individual breast tumours

    International Nuclear Information System (INIS)

    Wennmalm, Kristian; Bergh, Jonas

    2011-01-01

    The prognostic value of grading in breast cancer can be increased with microarray technology, but proposed strategies are disadvantaged by the use of specific training data or parallel microscopic grading. Here, we investigate the performance of a method that uses no information outside the breast profile of interest. In 251 profiled tumours we optimised a method that achieves grading by comparing rank means for genes predictive of high and low grade biology; a simpler method that allows for truly independent estimation of accuracy. Validation was carried out in 594 patients derived from several independent data sets. We found that accuracy was good: for low grade (G1) tumors 83- 94%, for high grade (G3) tumors 74- 100%. In keeping with aim of improved grading, two groups of intermediate grade (G2) cancers with significantly different outcome could be discriminated. This validates the concept of microarray-based grading in breast cancer, and provides a more practical method to achieve it. A simple R script for grading is available in an additional file. Clinical implementation could achieve better estimation of recurrence risk for 40 to 50% of breast cancer patients

  18. A simple method for assigning genomic grade to individual breast tumours

    Directory of Open Access Journals (Sweden)

    Bergh Jonas

    2011-07-01

    Full Text Available Abstract Background The prognostic value of grading in breast cancer can be increased with microarray technology, but proposed strategies are disadvantaged by the use of specific training data or parallel microscopic grading. Here, we investigate the performance of a method that uses no information outside the breast profile of interest. Results In 251 profiled tumours we optimised a method that achieves grading by comparing rank means for genes predictive of high and low grade biology; a simpler method that allows for truly independent estimation of accuracy. Validation was carried out in 594 patients derived from several independent data sets. We found that accuracy was good: for low grade (G1 tumors 83- 94%, for high grade (G3 tumors 74- 100%. In keeping with aim of improved grading, two groups of intermediate grade (G2 cancers with significantly different outcome could be discriminated. Conclusion This validates the concept of microarray-based grading in breast cancer, and provides a more practical method to achieve it. A simple R script for grading is available in an additional file. Clinical implementation could achieve better estimation of recurrence risk for 40 to 50% of breast cancer patients.

  19. Fabrication of Al/Diamond Particles Functionally Graded Materials by Centrifugal Sintered-Casting Method

    International Nuclear Information System (INIS)

    Watanabe, Yoshimi; Shibuya, Masafumi; Sato, Hisashi

    2013-01-01

    The continuous graded structure of functionally graded materials (FGMs) can be created under a centrifugal force. Centrifugal sintered-casting (CSC) method, proposed by the authors, is one of the fabrication methods of FGM under centrifugal force. This method is a combination of the centrifugal sintering method and centrifugal casting method. In this study, Al/diamond particle FGM was fabricated by the proposed method.

  20. MRI-derived Restriction Spectrum Imaging Cellularity Index is Associated with High Grade Prostate Cancer on Radical Prostatectomy Specimens

    Directory of Open Access Journals (Sweden)

    Michael Andre Liss

    2015-02-01

    Full Text Available Objectives: We evaluate a novel magnetic resonance imaging (MRI technique to improve detection of aggressive prostate cancer. Methods: We performed a retrospective analysis of presurgical prostate MRI scans using an advanced diffusion weighted imaging technique called Restriction Spectrum Imaging (RSI, which can be presented as a normalized z-score statistic (RSI z-score. Scans were acquired prior to radical prostatectomy. Prostatectomy specimens were processed using whole mount sectioning and regions of interest (ROIs were drawn around individual prostate cancer (PCa tumors. Corresponding ROIs were drawn on the MRI imaging and paired with ROIs in regions with no pathology. RSI z-score and conventional apparent diffusion coefficient (ADC values were recorded for each ROI. Paired t-test, ANOVA and logistic regression analyses were performed.Results: We evaluated 28 patients with 64 regions of interest (28 benign and 36 PCa. The mean difference in RSI z-score (PCa ROI – Benign ROI was 2.17 (SE = 0.11; p <0.001 and in ADC was 551 mm2/sec (SE = 80 mm2/sec; paired t-test, p <0.001. The differences in the means among all groups (benign, primary Gleason 3 and primary Gleason 4 was significant for both RSI z-score (F3,64 = 97.7, p <0.001 and ADC (F3,64 = 13.9, p <0.001. A t-test was performed on only PCa tumor ROIs (n=36 to determine prostate cancer aggressiveness (Gleason 3 vs. Gleason 4 revealing that RSI z-score was still significant (p = 0.03, whereas, ADC values were no longer significant (p = 0.08. In multivariable analysis adjusting for age and race, RSI z-score was associated with PCa aggressiveness (OR 10.3, 95%CI: 1.4-78.0, p=0.02 while ADC trended to significance (p=0.07. Conclusions: The RSI derived normalized cellularity index (RSI z-score is associated with aggressive prostate cancer as determined by pathologic Gleason scores. Further utilization of RSI techniques may serve to enhance standardized reporting systems.

  1. Comparison of early and late MRI in neonatal hypoxic-ischemic encephalopathy using three assessment methods

    International Nuclear Information System (INIS)

    Charon, Valerie; Proisy, Maia; Bruneau, Bertrand; Treguier, Catherine; Rozel, Celine; Ferre, Jean-Christophe; Beuchee, Alain; Chauvel, Jennifer

    2015-01-01

    There is no consensus on the optimum timing of MRI in neonates with hypoxic-ischemic encephalopathy treated with hypothermia. Reliable early imaging assessment might help managing treatment. To assess non-random differences between early and late MRI that might influence intensive-care decisions. This single-center retrospective study included all asphyxiated term neonates eligible for hypothermia treatment November 2009-July 2012. MRI scans were systematically performed at day 4 (early MRI) and day 11 of life as part of routine protocol. Two experienced pediatric radiologists reviewed both scans according to three assessment methods: a pattern classification, a scoring system and a simplified classification. Agreement between early and late imaging findings was assessed using Cohen's kappa coefficients. Thirty-three neonates were included. Interobserver agreement was excellent. Early MRI detected all severe injuries. Agreement between early and late MRI was excellent for the simplified classification (κ = 0.82), good for the pattern classification (κ = 0.64), and good to excellent for 3 scores out of 4 in the scoring system (κ = 0.70-0.89). Early MRI may provide valuable information about brain injury to help parents and neonatologists in intensive-care decisions at the end of hypothermia treatment. (orig.)

  2. Comparison of early and late MRI in neonatal hypoxic-ischemic encephalopathy using three assessment methods

    Energy Technology Data Exchange (ETDEWEB)

    Charon, Valerie; Proisy, Maia; Bruneau, Bertrand; Treguier, Catherine; Rozel, Celine [University Hospital, Department of Imaging, Hopital Sud, Rennes, Cedex 2 (France); Ferre, Jean-Christophe [University Hospital, Department of Neuroradiology, Hopital Pontchaillou, Rennes (France); Beuchee, Alain [University Hospital, Department of Neonatology, Hopital Sud, Rennes (France); Chauvel, Jennifer [Saint Brieuc Hospital, Department of Neonatology, Saint-Brieuc (France)

    2015-12-15

    There is no consensus on the optimum timing of MRI in neonates with hypoxic-ischemic encephalopathy treated with hypothermia. Reliable early imaging assessment might help managing treatment. To assess non-random differences between early and late MRI that might influence intensive-care decisions. This single-center retrospective study included all asphyxiated term neonates eligible for hypothermia treatment November 2009-July 2012. MRI scans were systematically performed at day 4 (early MRI) and day 11 of life as part of routine protocol. Two experienced pediatric radiologists reviewed both scans according to three assessment methods: a pattern classification, a scoring system and a simplified classification. Agreement between early and late imaging findings was assessed using Cohen's kappa coefficients. Thirty-three neonates were included. Interobserver agreement was excellent. Early MRI detected all severe injuries. Agreement between early and late MRI was excellent for the simplified classification (κ = 0.82), good for the pattern classification (κ = 0.64), and good to excellent for 3 scores out of 4 in the scoring system (κ = 0.70-0.89). Early MRI may provide valuable information about brain injury to help parents and neonatologists in intensive-care decisions at the end of hypothermia treatment. (orig.)

  3. The effectiveness and cost-effectiveness of intraoperative imaging in high-grade glioma resection; a comparative review of intraoperative ALA, fluorescein, ultrasound and MRI.

    Science.gov (United States)

    Eljamel, M Sam; Mahboob, Syed Osama

    2016-12-01

    Surgical resection of high-grade gliomas (HGG) is standard therapy because it imparts significant progression free (PFS) and overall survival (OS). However, HGG-tumor margins are indistinguishable from normal brain during surgery. Hence intraoperative technology such as fluorescence (ALA, fluorescein) and intraoperative ultrasound (IoUS) and MRI (IoMRI) has been deployed. This study compares the effectiveness and cost-effectiveness of these technologies. Critical literature review and meta-analyses, using MEDLINE/PubMed service. The list of references in each article was double-checked for any missing references. We included all studies that reported the use of ALA, fluorescein (FLCN), IoUS or IoMRI to guide HGG-surgery. The meta-analyses were conducted according to statistical heterogeneity between studies. If there was no heterogeneity, fixed effects model was used; otherwise, a random effects model was used. Statistical heterogeneity was explored by χ 2 and inconsistency (I 2 ) statistics. To assess cost-effectiveness, we calculated the incremental cost per quality-adjusted life-year (QALY). Gross total resection (GTR) after ALA, FLCN, IoUS and IoMRI was 69.1%, 84.4%, 73.4% and 70% respectively. The differences were not statistically significant. All four techniques led to significant prolongation of PFS and tended to prolong OS. However none of these technologies led to significant prolongation of OS compared to controls. The cost/QALY was $16,218, $3181, $6049 and $32,954 for ALA, FLCN, IoUS and IoMRI respectively. ALA, FLCN, IoUS and IoMRI significantly improve GTR and PFS of HGG. Their incremental cost was below the threshold for cost-effectiveness of HGG-therapy, denoting that each intraoperative technology was cost-effective on its own. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. PRIM: An Efficient Preconditioning Iterative Reweighted Least Squares Method for Parallel Brain MRI Reconstruction.

    Science.gov (United States)

    Xu, Zheng; Wang, Sheng; Li, Yeqing; Zhu, Feiyun; Huang, Junzhou

    2018-02-08

    The most recent history of parallel Magnetic Resonance Imaging (pMRI) has in large part been devoted to finding ways to reduce acquisition time. While joint total variation (JTV) regularized model has been demonstrated as a powerful tool in increasing sampling speed for pMRI, however, the major bottleneck is the inefficiency of the optimization method. While all present state-of-the-art optimizations for the JTV model could only reach a sublinear convergence rate, in this paper, we squeeze the performance by proposing a linear-convergent optimization method for the JTV model. The proposed method is based on the Iterative Reweighted Least Squares algorithm. Due to the complexity of the tangled JTV objective, we design a novel preconditioner to further accelerate the proposed method. Extensive experiments demonstrate the superior performance of the proposed algorithm for pMRI regarding both accuracy and efficiency compared with state-of-the-art methods.

  5. Graphical programming interface: A development environment for MRI methods.

    Science.gov (United States)

    Zwart, Nicholas R; Pipe, James G

    2015-11-01

    To introduce a multiplatform, Python language-based, development environment called graphical programming interface for prototyping MRI techniques. The interface allows developers to interact with their scientific algorithm prototypes visually in an event-driven environment making tasks such as parameterization, algorithm testing, data manipulation, and visualization an integrated part of the work-flow. Algorithm developers extend the built-in functionality through simple code interfaces designed to facilitate rapid implementation. This article shows several examples of algorithms developed in graphical programming interface including the non-Cartesian MR reconstruction algorithms for PROPELLER and spiral as well as spin simulation and trajectory visualization of a FLORET example. The graphical programming interface framework is shown to be a versatile prototyping environment for developing numeric algorithms used in the latest MR techniques. © 2014 Wiley Periodicals, Inc.

  6. Grading system to categorize breast MRI using BI-RADS 5th edition: a statistical study of non-mass enhancement descriptors in terms of probability of malignancy.

    Science.gov (United States)

    Asada, Tatsunori; Yamada, Takayuki; Kanemaki, Yoshihide; Fujiwara, Keishi; Okamoto, Satoko; Nakajima, Yasuo

    2018-03-01

    To analyze the association of breast non-mass enhancement descriptors in the BI-RADS 5th edition with malignancy, and to establish a grading system and categorization of descriptors. This study was approved by our institutional review board. A total of 213 patients were enrolled. Breast MRI was performed with a 1.5-T MRI scanner using a 16-channel breast radiofrequency coil. Two radiologists determined internal enhancement and distribution of non-mass enhancement by consensus. Corresponding pathologic diagnoses were obtained by either biopsy or surgery. The probability of malignancy by descriptor was analyzed using Fisher's exact test and multivariate logistic regression analysis. The probability of malignancy by category was analyzed using Fisher's exact and multi-group comparison tests. One hundred seventy-eight lesions were malignant. Multivariate model analysis showed that internal enhancement (homogeneous vs others, p probability of malignancy (p < 0.0001). The three-grade criteria and categorization by sum-up grades of descriptors appear valid for non-mass enhancement.

  7. Synthesis of multiwalled carbon nanotube from different grades of carbon black using arc discharge method

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Neha, E-mail: n4neha31@gmail.com [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Sharma, N. N. [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Director, School of Automobile, Mechanical & Mechatronics, Manipal University,Jaipur,India (India)

    2016-04-13

    This paper describes the synthesis of nanotube from different grades (Tread * A(non-ASTM), N134,N121,N660 and N330)of carbon black using DC arc discharge method at 40A current for 60sec. Carbon black samples of different grades were procured from industry (Aditya Birla Science and Technology Limited, India). Scanning Electron Micrographs (SEM) of the deposited carbon nanostructures suggests that MWCNTs are formed at 40A and for a minimal exposure time of 60sec.The result formed indicates the N330 grade of carbon black gets converted to MWCNTs (Multiwall Carbon nanotube) as compared to other grades.

  8. The registration accuracy analysis of different CT-MRI imaging fusion method in brain tumor

    International Nuclear Information System (INIS)

    Lu Jie; Yin Yong; Shao Qian; Zhang Zicheng; Chen Jinhu; Chen Zhaoqiu

    2010-01-01

    Objective: To find an effective CT-MRI image fusion protocol in brain tumor by analyzing the registration accuracy of different methods. Methods: The simulation CT scan and MRI T 1 WI imaging of 10 brain tumor patients obtained with same position were registered by Tris-Axes landmark ,Tris-Axes landmark + manual adjustment, mutual information and mutual information + manual adjustment method. The clinical tumor volume (CTV) were contoured on both CT and MRI images respectively. The accuracy of image fusion was assessed by the mean distance of five bone markers (d 1-5 ), central position of CTV (d CTV ) the percentage of CTV overlap (P CT-MRI ) between CT and MRI images. The difference between different methods was analyzed by Freedman M non-parameter test. Results: The difference of the means d1-5 between the Tris-Axes landmark,Tris-Axes landmark plus manual adjustment,mutual information and mutual information plus manual adjustment methods were 0.28 cm ±0.12 cm, 0.15 cm ±0.02 cm, 0.25 cm± 0.19 cm, 0.10 cm ± 0.06 cm, (M = 14.41, P = 0.002). the means d CTV were 0.59 cm ± 0.28 cm, 0.60 cm± 0.32 cm, 0.58 cm ± 0.39 cm, 0.42 cm± 0.30 cm (M = 9.72, P = 0.021), the means P CT-MRI were 0.69% ±0.18%, 0.68% ±0.16%, 0.66% ±0.17%, 0.74% ±0.14% (M =14.82, P=0.002), respectively. Conclusions: Mutual information plus manual adjustment registration method was the preferable fusion method for brain tumor patients. (authors)

  9. Cardiac MRI in patients with complex CHD following primary or secondary implantation of MRI-conditional pacemaker system.

    Science.gov (United States)

    Al-Wakeel, Nadya; O h-Ici, Darach; Schmitt, Katharina R; Messroghli, Daniel R; Riesenkampff, Eugénie; Berger, Felix; Kuehne, Titus; Peters, Bjoern

    2016-02-01

    In patients with CHD, cardiac MRI is often indicated for functional and anatomical assessment. With the recent introduction of MRI-conditional pacemaker systems, cardiac MRI has become accessible for patients with pacemakers. The present clinical study aims to evaluate safety, susceptibility artefacts, and image reading of cardiac MRI in patients with CHD and MRI-conditional pacemaker systems. Material and methods CHD patients with MRI-conditional pacemaker systems and a clinical need for cardiac MRI were examined with a 1.5-T MRI system. Lead function was tested before and after MRI. Artefacts and image readings were evaluated using a four-point grading scale. A total of nine patients with CHD (mean age 34.0 years, range 19.5-53.6 years) received a total of 11 cardiac MRI examinations. Owing to clinical indications, seven patients had previously been converted from conventional to MRI-conditional pacemaker systems. All MRI examinations were completed without adverse effects. Device testing immediately after MRI and at follow-up showed no alteration of pacemaker device and lead function. Clinical questions could be addressed and answered in all patients. Cardiac MRI can be performed safely with high certainty of diagnosis in CHD patients with MRI-conditional pacemaker systems. In case of clinically indicated lead and box changing, CHD patients with non-MRI-conditional pacemaker systems should be considered for complete conversion to MRI-conditional systems.

  10. MRI-Based Computed Tomography Metal Artifact Correction Method for Improving Proton Range Calculation Accuracy

    International Nuclear Information System (INIS)

    Park, Peter C.; Schreibmann, Eduard; Roper, Justin; Elder, Eric; Crocker, Ian; Fox, Tim; Zhu, X. Ronald; Dong, Lei; Dhabaan, Anees

    2015-01-01

    Purpose: Computed tomography (CT) artifacts can severely degrade dose calculation accuracy in proton therapy. Prompted by the recently increased popularity of magnetic resonance imaging (MRI) in the radiation therapy clinic, we developed an MRI-based CT artifact correction method for improving the accuracy of proton range calculations. Methods and Materials: The proposed method replaces corrupted CT data by mapping CT Hounsfield units (HU number) from a nearby artifact-free slice, using a coregistered MRI. MRI and CT volumetric images were registered with use of 3-dimensional (3D) deformable image registration (DIR). The registration was fine-tuned on a slice-by-slice basis by using 2D DIR. Based on the intensity of paired MRI pixel values and HU from an artifact-free slice, we performed a comprehensive analysis to predict the correct HU for the corrupted region. For a proof-of-concept validation, metal artifacts were simulated on a reference data set. Proton range was calculated using reference, artifactual, and corrected images to quantify the reduction in proton range error. The correction method was applied to 4 unique clinical cases. Results: The correction method resulted in substantial artifact reduction, both quantitatively and qualitatively. On respective simulated brain and head and neck CT images, the mean error was reduced from 495 and 370 HU to 108 and 92 HU after correction. Correspondingly, the absolute mean proton range errors of 2.4 cm and 1.7 cm were reduced to less than 2 mm in both cases. Conclusions: Our MRI-based CT artifact correction method can improve CT image quality and proton range calculation accuracy for patients with severe CT artifacts

  11. Grading and outcome prediction of pediatric diffuse astrocytic tumors with diffusion and arterial spin labeling perfusion MRI in comparison with 18F-DOPA PET

    Energy Technology Data Exchange (ETDEWEB)

    Morana, Giovanni; Tortora, Domenico; Severino, Mariasavina; Rossi, Andrea [Istituto Giannina Gaslini, Neuroradiology Unit, Genoa (Italy); Piccardo, Arnoldo; Cabria, Manlio [Ente Ospedaliero Ospedali Galliera, Nuclear Medicine Unit, Genoa (Italy); Puntoni, Matteo [Ente Ospedaliero Ospedali Galliera, Clinical Trial Unit, Scientific Directorate, Genoa (Italy); Nozza, Paolo [Istituto Giannina Gaslini, Pathology Unit, Genoa (Italy); Ravegnani, Marcello; Consales, Alessandro; Mascelli, Samantha; Raso, Alessandro [Istituto Giannina Gaslini, Neurosurgery Unit, Genoa (Italy); Verrico, Antonio; Milanaccio, Claudia [Istituto Giannina Gaslini, Neuro-oncology Unit, Genoa (Italy)

    2017-11-15

    The aim of this study was to investigate MRI-derived diffusion weighted imaging (DWI) and arterial spin labeling (ASL) perfusion imaging in comparison with {sup 18}F-dihydroxyphenylalanine (DOPA) PET with respect to diagnostic performance in tumor grading and outcome prediction in pediatric patients with diffuse astrocytic tumors (DAT). We retrospectively analyzed 26 children with histologically proven treatment naive low and high grade DAT who underwent ASL and DWI performed within 2 weeks of {sup 18}F-DOPA PET. Relative ASL-derived cerebral blood flow max (rCBF max) and DWI-derived minimum apparent diffusion coefficient (rADC min) were compared with {sup 18}F-DOPA uptake tumor/normal tissue (T/N) and tumor/striatum (T/S) ratios, and correlated with World Health Organization (WHO) tumor grade and progression-free survival (PFS). Statistics included Pearson's chi-square and Mann-Whitney U tests, Spearman's rank correlation, receiver operating characteristic (ROC) analysis, discriminant function analysis (DFA), Kaplan-Meier survival curve, and Cox analysis. A significant correlation was demonstrated between rCBF max, rADC min, and {sup 18}F-DOPA PET data (p < 0.001). Significant differences in terms of rCBF max, rADC min, and {sup 18}F-DOPA uptake were found between low- and high-grade DAT (p ≤ 0.001). ROC analysis and DFA demonstrated that T/S and T/N values were the best parameters for predicting tumor progression (AUC 0.93, p < 0.001). On univariate analysis, all diagnostic tools correlated with PFS (p ≤ 0.001); however, on multivariate analysis, only {sup 18}F-DOPA uptake remained significantly associated with outcome (p ≤ 0.03), while a trend emerged for rCBF max (p = 0.09) and rADC min (p = 0.08). The combination of MRI and PET data increased the predictive power for prognosticating tumor progression (AUC 0.97, p < 0.001). DWI, ASL and {sup 18}F-DOPA PET provide useful complementary information for pediatric DAT grading. {sup 18}F-DOPA uptake

  12. Evidence for Policy Making: Clinical Appropriateness Study of Lumbar Spine MRI Prescriptions Using RAND Appropriateness Method

    Directory of Open Access Journals (Sweden)

    Hossein Yousefi Manesh

    2013-01-01

    Full Text Available MRI is a new and expensive diagnostic technology, which has been used increasingly all over the world. Low back pain is a worldwide prevalent disorder and MRI technique is one of the several ways to diagnose it. This paper aims to identify the appropriateness of lumbar spine MRI prescriptions in Shiraz teaching hospitals using standardized RAND Appropriateness Method (RAM criteria. Methods This study consisted of two phases. The first phase involved a qualitative enquiry and the second phase had a quantitative cross-sectional nature. In the first phase RAM was used for developing lumbar spine MRI indications and scenarios. In the second phase, the finalized scenarios were compared with the history and physical examination of 300 patients with low back pain. The rate of appropriateness of lumbar spine MRI prescription was then calculated. Results Of 300 cases of lumbar spine MRI prescriptions, approximately 167 (56% were considered inappropriate, 72 (24% were uncertain, and 61 (20% were deemed to be appropriate. The economic burden of inappropriate prescriptions was calculated at 88,009,000 Rials. In addition, the types of expertise and physical examination were considered as related factors to appropriateness of prescriptions. Conclusion In conclusion, a large proportion of lumbar spine MRI prescriptions, which result in financial burden on the insurance companies and the patients alike is unnecessary. This study suggests that policy makers consider this evidence while decision-making. Our findings highlight the imperative role of Health Technology Assessment (HTA and Clinical Practice Guidelines (CPGs. As a result, developing local clinical guidelines may create the commitment needed in physicians in prescribing appropriate prescriptions within the health sector. The study further recommends that appropriate scenarios should be considered as a criterion for payment and reimbursement.

  13. Preparation of high purification and food grade phosphoric acid from technical grade phosphoric acid by liquid-liquid detraction method

    International Nuclear Information System (INIS)

    Alimoradi, M.; Borji, F.; Kishani, A.

    2002-01-01

    Pay attention to increasing consumption of high purification and food grade phosphoric acid in various industries and food industries and on in on hand and lack of preparation between production and distribution of this products its purification is so vital. In this article of liquid-liquid extraction method with normal hexane-mixture of ammonia and acetone-diisopropyl alcohol and normal butanol solvents and these determination of distribution coefficient each one with ph-me try titration we can evaluate effectiveness and sufficiency each one. Because of proper coefficient distribution and its local production of normal butanol solvent and low price is the best solvent. To phosphoric acid modifying coefficient distribution for extraction of phosphoric acid we can add a little value sulfuric acid to the mixture and to remove flouride impurity we add a little Na 2 O. After extraction stage extracted phosphoric acid in the normal strips by evaluating with distilled water and then by passing the carbon active bed and following passes of cationic resine column and concentrated with vacuum distillation. Conclusion of this article is produce of phosphoric acid 85% w/w and food grade from impure phosphoric acid 52% w/w with technical grade

  14. Automated Processing of Dynamic Contrast-Enhanced MRI: Correlation of Advanced Pharmacokinetic Metrics with Tumor Grade in Pediatric Brain Tumors.

    Science.gov (United States)

    Vajapeyam, S; Stamoulis, C; Ricci, K; Kieran, M; Poussaint, T Young

    2017-01-01

    Pharmacokinetic parameters from dynamic contrast-enhanced MR imaging have proved useful for differentiating brain tumor grades in adults. In this study, we retrospectively reviewed dynamic contrast-enhanced perfusion data from children with newly diagnosed brain tumors and analyzed the pharmacokinetic parameters correlating with tumor grade. Dynamic contrast-enhanced MR imaging data from 38 patients were analyzed by using commercially available software. Subjects were categorized into 2 groups based on pathologic analyses consisting of low-grade (World Health Organization I and II) and high-grade (World Health Organization III and IV) tumors. Pharmacokinetic parameters were compared between the 2 groups by using linear regression models. For parameters that were statistically distinct between the 2 groups, sensitivity and specificity were also estimated. Eighteen tumors were classified as low-grade, and 20, as high-grade. Transfer constant from the blood plasma into the extracellular extravascular space (K trans ), rate constant from extracellular extravascular space back into blood plasma (K ep ), and extracellular extravascular volume fraction (V e ) were all significantly correlated with tumor grade; high-grade tumors showed higher K trans , higher K ep , and lower V e . Although all 3 parameters had high specificity (range, 82%-100%), K ep had the highest specificity for both grades. Optimal sensitivity was achieved for V e , with a combined sensitivity of 76% (compared with 71% for K trans and K ep ). Pharmacokinetic parameters derived from dynamic contrast-enhanced MR imaging can effectively discriminate low- and high-grade pediatric brain tumors. © 2017 by American Journal of Neuroradiology.

  15. A SVM-based quantitative fMRI method for resting-state functional network detection.

    Science.gov (United States)

    Song, Xiaomu; Chen, Nan-kuei

    2014-09-01

    Resting-state functional magnetic resonance imaging (fMRI) aims to measure baseline neuronal connectivity independent of specific functional tasks and to capture changes in the connectivity due to neurological diseases. Most existing network detection methods rely on a fixed threshold to identify functionally connected voxels under the resting state. Due to fMRI non-stationarity, the threshold cannot adapt to variation of data characteristics across sessions and subjects, and generates unreliable mapping results. In this study, a new method is presented for resting-state fMRI data analysis. Specifically, the resting-state network mapping is formulated as an outlier detection process that is implemented using one-class support vector machine (SVM). The results are refined by using a spatial-feature domain prototype selection method and two-class SVM reclassification. The final decision on each voxel is made by comparing its probabilities of functionally connected and unconnected instead of a threshold. Multiple features for resting-state analysis were extracted and examined using an SVM-based feature selection method, and the most representative features were identified. The proposed method was evaluated using synthetic and experimental fMRI data. A comparison study was also performed with independent component analysis (ICA) and correlation analysis. The experimental results show that the proposed method can provide comparable or better network detection performance than ICA and correlation analysis. The method is potentially applicable to various resting-state quantitative fMRI studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Developing Criteria for Lumbar Spine Magnetic Resonance Imaging (MRI) Using RAND Appropriateness Method (RAM)

    International Nuclear Information System (INIS)

    Keshtkaran, Ali; Bagheri, Mohammad Hadi; Ostovar, Rahim; Salari, Hedayat; Farokhi, Majid Reza; Esfandiari, Atefeh; Yousefimanesh, Hossein

    2012-01-01

    Studies show that a large proportion of healthcare offered may be inappropriate or unnecessary. Magnetic resonance imaging (MRI) is a new and expensive diagnostic technology which has been increasingly used all over the world. Moreover, this trend has been more rapidly increasing in Iran. Low back pain is a common disorder all over the world and MRI technique is one of the several ways to assess its cause. The present study aims to develop scenarios for lumbar spine MRI. In the present study, the RAND Appropriateness Method (RAM) was used in order to reach consensus regarding developing scenarios for lumbar spine MRI. We generated scenarios from valid clinical guidelines as well as the experts’ opinion. The panel members included nine specialists from various medical specialties that had scored scenarios in two rounds, the first of which was without interaction, while the second one was with interaction. We extracted 97 scenarios for the lumbar spine MRI in the scenario extracting phase of the study and the panel members added 18 scenarios. After implementation of two rounds, the scenarios were categorized into three ranges. Sixty seven (58%) of the scenarios were considered as appropriate, 45 (39%) as uncertain, and three (2.6%) as inappropriate. RAM is useful for identifying stakeholder views in settings with limited resources. Since RAM has precise instructions for consensus developing, a large number of scenarios were considered as uncertain. Therefore, more research has to be conducted on the issue

  17. Regularization of DT-MRI Using 3D Median Filtering Methods

    Directory of Open Access Journals (Sweden)

    Soondong Kwon

    2014-01-01

    Full Text Available DT-MRI (diffusion tensor magnetic resonance imaging tractography is a method to determine the architecture of axonal fibers in the central nervous system by computing the direction of the principal eigenvectors obtained from tensor matrix, which is different from the conventional isotropic MRI. Tractography based on DT-MRI is known to need many computations and is highly sensitive to noise. Hence, adequate regularization methods, such as image processing techniques, are in demand. Among many regularization methods we are interested in the median filtering method. In this paper, we extended two-dimensional median filters already developed to three-dimensional median filters. We compared four median filtering methods which are two-dimensional simple median method (SM2D, two-dimensional successive Fermat method (SF2D, three-dimensional simple median method (SM3D, and three-dimensional successive Fermat method (SF3D. Three kinds of synthetic data with different altitude angles from axial slices and one kind of human data from MR scanner are considered for numerical implementation by the four filtering methods.

  18. Sparse PCA, a new method for unsupervised analyses of fMRI data

    DEFF Research Database (Denmark)

    Sjöstrand, Karl; Lund, Torben E.; Madsen, Kristoffer Hougaard

    2006-01-01

    favorable circumstances, one of more of these signals describe activation patterns, while others model noise and other nuisance factors. This work introduces a competing method for fMRI analysis known as sparse principal component analysis (SPCA). We argue that SPCA is less committed than ICA and show...... that similar results, with better suppression of noise, are obtained....

  19. Application of stereological methods to estimate post-mortem brain surface area using 3T MRI

    DEFF Research Database (Denmark)

    Furlong, Carolyn; García-Fiñana, Marta; Puddephat, Michael

    2013-01-01

    The Cavalieri and Vertical Sections methods of design based stereology were applied in combination with 3 tesla (i.e. 3T) Magnetic Resonance Imaging (MRI) to estimate cortical and subcortical volume, area of the pial surface, area of the grey-white matter boundary, and thickness of the cerebral...

  20. Automated lesion detection on MRI scans using combined unsupervised and supervised methods

    International Nuclear Information System (INIS)

    Guo, Dazhou; Fridriksson, Julius; Fillmore, Paul; Rorden, Christopher; Yu, Hongkai; Zheng, Kang; Wang, Song

    2015-01-01

    Accurate and precise detection of brain lesions on MR images (MRI) is paramount for accurately relating lesion location to impaired behavior. In this paper, we present a novel method to automatically detect brain lesions from a T1-weighted 3D MRI. The proposed method combines the advantages of both unsupervised and supervised methods. First, unsupervised methods perform a unified segmentation normalization to warp images from the native space into a standard space and to generate probability maps for different tissue types, e.g., gray matter, white matter and fluid. This allows us to construct an initial lesion probability map by comparing the normalized MRI to healthy control subjects. Then, we perform non-rigid and reversible atlas-based registration to refine the probability maps of gray matter, white matter, external CSF, ventricle, and lesions. These probability maps are combined with the normalized MRI to construct three types of features, with which we use supervised methods to train three support vector machine (SVM) classifiers for a combined classifier. Finally, the combined classifier is used to accomplish lesion detection. We tested this method using T1-weighted MRIs from 60 in-house stroke patients. Using leave-one-out cross validation, the proposed method can achieve an average Dice coefficient of 73.1 % when compared to lesion maps hand-delineated by trained neurologists. Furthermore, we tested the proposed method on the T1-weighted MRIs in the MICCAI BRATS 2012 dataset. The proposed method can achieve an average Dice coefficient of 66.5 % in comparison to the expert annotated tumor maps provided in MICCAI BRATS 2012 dataset. In addition, on these two test datasets, the proposed method shows competitive performance to three state-of-the-art methods, including Stamatakis et al., Seghier et al., and Sanjuan et al. In this paper, we introduced a novel automated procedure for lesion detection from T1-weighted MRIs by combining both an unsupervised and a

  1. Evaluation of left ventricular volume by MRI using modified Simpson's rule method

    International Nuclear Information System (INIS)

    Okamura, Masahiro; Kondo, Takeshi; Anno, Naoko

    1990-01-01

    The conventional contrast left ventriculogrpahy (LVG) has been the gold standard for estimating left ventricular volume (LVV), but it is an invasive technique, and volume overload must be caused by contrast medium. the true left ventricular (LV) long axis may not be obtained by LVG in routine right anterior oblique (RAO) projection. MRI, on the other hand, is noninvasive, does not require contrast medium, and permits to obtain the true LV long axis sections. Thus, MRI seems the ideal technique for estimating LVV. To estimate LVV, we have developed the on-line programs for calculating LVV by single-plane (SMS) or biplane modified Simpson's rule method (BMS), and have applied these programs to the water in the bottle with the elliptic short axis plane, normal volunteer and patients with various heart diseases. In the water phantom, the water volume calculated by the BMS was more accurate than the SMS. In nine normal volunteers, multiple LV short axis sections in each end-systole and end-diastole were obtained by ECG-gated spin echo MRI, LVV as standard was calculated by true Simpson's rule method (TS) on these images. Then both vertical and horizontal LV long axis sections were also obtained by ECG-gated field echo (FE) rephasing cine MRI, LVV was calculated by the BMS or SMS on these images. The BMS or SMS significantly correlated (r=0.974, r=0.927, 0.947) with TS for estimating LVV, respectively. In 20 patients with various heart diseases, both vertical and horizontal LV long axis sections were obtained by FE cine MRI. LVV (r=0.907 and r=0.901) and EF (r=0.822 and r=0.938) calculated by the SMS on the vertical or horizontal LV long axis sections significantly correlated with the conventional RAO-LVG, respectively. In conclusion, the MRI using our on-line programs would be clinically useful for estimating LVV and EF. (author)

  2. Altered effective connectivity network of the basal ganglia in low-grade hepatic encephalopathy: a resting-state fMRI study with Granger causality analysis.

    Directory of Open Access Journals (Sweden)

    Rongfeng Qi

    Full Text Available BACKGROUND: The basal ganglia often show abnormal metabolism and intracranial hemodynamics in cirrhotic patients with hepatic encephalopathy (HE. Little is known about how the basal ganglia affect other brain system and is affected by other brain regions in HE. The purpose of this study was to investigate whether the effective connectivity network associated with the basal ganglia is disturbed in HE patients by using resting-state functional magnetic resonance imaging (rs-fMRI. METHODOLOGY/PRINCIPAL FINDINGS: Thirty five low-grade HE patients and thirty five age- and gender- matched healthy controls participated in the rs-fMRI scans. The effective connectivity networks associated with the globus pallidus, the primarily affected region within basal ganglia in HE, were characterized by using the Granger causality analysis and compared between HE patients and healthy controls. Pearson correlation analysis was performed between the abnormal effective connectivity and venous blood ammonia levels and neuropsychological performances of all HE patients. Compared with the healthy controls, patients with low-grade HE demonstrated mutually decreased influence between the globus pallidus and the anterior cingulate cortex (ACC, cuneus, bi-directionally increased influence between the globus pallidus and the precuneus, and either decreased or increased influence from and to the globus pallidus in many other frontal, temporal, parietal gyri, and cerebellum. Pearson correlation analyses revealed that the blood ammonia levels in HE patients negatively correlated with effective connectivity from the globus pallidus to ACC, and positively correlated with that from the globus pallidus to precuneus; and the number connectivity test scores in patients negatively correlated with the effective connectivity from the globus pallidus to ACC, and from superior frontal gyrus to globus pallidus. CONCLUSIONS/SIGNIFICANCE: Low-grade HE patients had disrupted effective

  3. An optimizing design method for a compact iron shielded superconducting magnet for use in MRI

    International Nuclear Information System (INIS)

    Tang Xin; Zu Donglin; Wang Tao; Han Baohui

    2010-01-01

    A method is developed for designing a special iron shielded superconducting magnet for MRI in this paper. The shield is designed as an integral part of the cryostat and high permeability and high saturated magnetization iron material is adopted. This scheme will result in a compact iron shielded magnet. In the presented design, the finite element (FE) method is adopted to calculate the magnetic field produced by superconducting coils and nonlinear iron material. The FE method is incorporated into the simulated annealing method which is employed for corresponding optimization. Therefore, geometrical configurations of both coils and iron shield can be optimized together. This method can deal with discrete design variables which are defined to describe the cable arrangements of coil cross sections. A detailed algorithm of the present design is described and an example for designing a 1.5 T clinical iron shielded magnet for MRI is shown.

  4. Grading of Chinese Cantonese Sausage Using Hyperspectral Imaging Combined with Chemometric Methods

    Science.gov (United States)

    Gong, Aiping; Zhu, Susu; He, Yong; Zhang, Chu

    2017-01-01

    Fast and accurate grading of Chinese Cantonese sausage is an important concern for customers, organizations, and the industry. Hyperspectral imaging in the spectral range of 874–1734 nm, combined with chemometric methods, was applied to grade Chinese Cantonese sausage. Three grades of intact and sliced Cantonese sausages were studied, including the top, first, and second grades. Support vector machine (SVM) and random forests (RF) techniques were used to build two different models. Second derivative spectra and RF were applied to select optimal wavelengths. The optimal wavelengths were the same for intact and sliced sausages when selected from second derivative spectra, while the optimal wavelengths for intact and sliced sausages selected using RF were quite similar. The SVM and RF models, using full spectra and the optimal wavelengths, obtained acceptable results for intact and sliced sausages. Both models for intact sausages performed better than those for sliced sausages, with a classification accuracy of the calibration and prediction set of over 90%. The overall results indicated that hyperspectral imaging combined with chemometric methods could be used to grade Chinese Cantonese sausages, with intact sausages being better suited for grading. This study will help to develop fast and accurate online grading of Cantonese sausages, as well as other sausages. PMID:28757578

  5. A Total Variation-Based Reconstruction Method for Dynamic MRI

    Directory of Open Access Journals (Sweden)

    Germana Landi

    2008-01-01

    Full Text Available In recent years, total variation (TV regularization has become a popular and powerful tool for image restoration and enhancement. In this work, we apply TV minimization to improve the quality of dynamic magnetic resonance images. Dynamic magnetic resonance imaging is an increasingly popular clinical technique used to monitor spatio-temporal changes in tissue structure. Fast data acquisition is necessary in order to capture the dynamic process. Most commonly, the requirement of high temporal resolution is fulfilled by sacrificing spatial resolution. Therefore, the numerical methods have to address the issue of images reconstruction from limited Fourier data. One of the most successful techniques for dynamic imaging applications is the reduced-encoded imaging by generalized-series reconstruction method of Liang and Lauterbur. However, even if this method utilizes a priori data for optimal image reconstruction, the produced dynamic images are degraded by truncation artifacts, most notably Gibbs ringing, due to the spatial low resolution of the data. We use a TV regularization strategy in order to reduce these truncation artifacts in the dynamic images. The resulting TV minimization problem is solved by the fixed point iteration method of Vogel and Oman. The results of test problems with simulated and real data are presented to illustrate the effectiveness of the proposed approach in reducing the truncation artifacts of the reconstructed images.

  6. Finite element method for radiation heat transfer in multi-dimensional graded index medium

    International Nuclear Information System (INIS)

    Liu, L.H.; Zhang, L.; Tan, H.P.

    2006-01-01

    In graded index medium, ray goes along a curved path determined by Fermat principle, and curved ray-tracing is very difficult and complex. To avoid the complicated and time-consuming computation of curved ray trajectories, a finite element method based on discrete ordinate equation is developed to solve the radiative transfer problem in a multi-dimensional semitransparent graded index medium. Two particular test problems of radiative transfer are taken as examples to verify this finite element method. The predicted dimensionless net radiative heat fluxes are determined by the proposed method and compared with the results obtained by finite volume method. The results show that the finite element method presented in this paper has a good accuracy in solving the multi-dimensional radiative transfer problem in semitransparent graded index medium

  7. Comparison between MRI-based attenuation correction methods for brain PET in dementia patients

    International Nuclear Information System (INIS)

    Cabello, Jorge; Lukas, Mathias; Pyka, Thomas; Nekolla, Stephan G.; Ziegler, Sibylle I.; Rota Kops, Elena; Shah, N. Jon; Ribeiro, Andre; Yakushev, Igor

    2016-01-01

    The combination of Positron Emission Tomography (PET) with magnetic resonance imaging (MRI) in hybrid PET/MRI scanners offers a number of advantages in investigating brain structure and function. A critical step of PET data reconstruction is attenuation correction (AC). Accounting for bone in attenuation maps (μ-map) was shown to be important in brain PET studies. While there are a number of MRI-based AC methods, no systematic comparison between them has been performed so far. The aim of this work was to study the different performance obtained by some of the recent methods presented in the literature. To perform such a comparison, we focused on [ 18 F]-Fluorodeoxyglucose-PET/MRI neurodegenerative dementing disorders, which are known to exhibit reduced levels of glucose metabolism in certain brain regions. Four novel methods were used to calculate μ-maps from MRI data of 15 patients with Alzheimer's dementia (AD). The methods cover two atlas-based methods, a segmentation method, and a hybrid template/segmentation method. Additionally, the Dixon-based and a UTE-based method, offered by a vendor, were included in the comparison. Performance was assessed at three levels: tissue identification accuracy in the μ-map, quantitative accuracy of reconstructed PET data in specific brain regions, and precision in diagnostic images at identifying hypometabolic areas. Quantitative regional errors of -20-10 % were obtained using the vendor's AC methods, whereas the novel methods produced errors in a margin of ±5 %. The obtained precision at identifying areas with abnormally low levels of glucose uptake, potentially regions affected by AD, were 62.9 and 79.5 % for the two vendor AC methods, the former ignoring bone and the latter including bone information. The precision increased to 87.5-93.3 % in average for the four new methods, exhibiting similar performances. We confirm that the AC methods based on the Dixon and UTE sequences provided by the vendor are inferior

  8. Comparison between MRI-based attenuation correction methods for brain PET in dementia patients

    Energy Technology Data Exchange (ETDEWEB)

    Cabello, Jorge; Lukas, Mathias; Pyka, Thomas; Nekolla, Stephan G.; Ziegler, Sibylle I. [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Rota Kops, Elena; Shah, N. Jon [Forschungszentrum Juelich GmbH, Institute of Neuroscience and Medicine 4, Medical Imaging Physics, Juelich (Germany); Ribeiro, Andre [Forschungszentrum Juelich GmbH, Institute of Neuroscience and Medicine 4, Medical Imaging Physics, Juelich (Germany); Institute of Biophysics and Biomedical Engineering, Lisbon (Portugal); Yakushev, Igor [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Institute TUM Neuroimaging Center (TUM-NIC), Munich (Germany)

    2016-11-15

    The combination of Positron Emission Tomography (PET) with magnetic resonance imaging (MRI) in hybrid PET/MRI scanners offers a number of advantages in investigating brain structure and function. A critical step of PET data reconstruction is attenuation correction (AC). Accounting for bone in attenuation maps (μ-map) was shown to be important in brain PET studies. While there are a number of MRI-based AC methods, no systematic comparison between them has been performed so far. The aim of this work was to study the different performance obtained by some of the recent methods presented in the literature. To perform such a comparison, we focused on [{sup 18}F]-Fluorodeoxyglucose-PET/MRI neurodegenerative dementing disorders, which are known to exhibit reduced levels of glucose metabolism in certain brain regions. Four novel methods were used to calculate μ-maps from MRI data of 15 patients with Alzheimer's dementia (AD). The methods cover two atlas-based methods, a segmentation method, and a hybrid template/segmentation method. Additionally, the Dixon-based and a UTE-based method, offered by a vendor, were included in the comparison. Performance was assessed at three levels: tissue identification accuracy in the μ-map, quantitative accuracy of reconstructed PET data in specific brain regions, and precision in diagnostic images at identifying hypometabolic areas. Quantitative regional errors of -20-10 % were obtained using the vendor's AC methods, whereas the novel methods produced errors in a margin of ±5 %. The obtained precision at identifying areas with abnormally low levels of glucose uptake, potentially regions affected by AD, were 62.9 and 79.5 % for the two vendor AC methods, the former ignoring bone and the latter including bone information. The precision increased to 87.5-93.3 % in average for the four new methods, exhibiting similar performances. We confirm that the AC methods based on the Dixon and UTE sequences provided by the vendor are

  9. Application of cine MRI-tagging method to aortic dessection

    International Nuclear Information System (INIS)

    Yoshioka, Kunihiro; Takahashi, Tsuneo; Kamata, Hiroyuki; Kikuchi, Kenichi; Yamaguchi, Kojiro.

    1992-01-01

    For the evaluation of aortic dissection, ECG-gated SE or cine MR imaging has been usually performed. However, detection of slow flow in the false lumen and differentiation between mural thrombus and slow flow are sometimes difficult. Because paradoxical enhancement due to slow blood flow simulates thrombus. We performed cine MR imaging with persaturation tagging, which clearly showed differentiation between thrombus and paradoxical enhancement. We concluded that cine MR imaging with tagging method was useful to evaluate the slow flow and thrombus in the false lumen. (author)

  10. Screening of various low-grade biomass materials for low temperature gasification: Method development and application

    DEFF Research Database (Denmark)

    Thomsen, Tobias Pape; Ravenni, Giulia; Holm, Jens Kai

    2015-01-01

    references. The technical assessment is supplemented by an evaluation of practical application and overall energy balance. Applying the developed method to 4 references and 18 unproven low-grade potential fuels, indicated that one of these unproven candidates was most likely unsuited for Pyroneer...... method and the subsequent use of the method to identify promising e but currently unproven, low-grade biomass resources for conversion in Pyroneer systems. The technical assessment is conducted by comparing the results from a series of physical-mechanical and thermochemical experiments to a set of proven...

  11. Absolute cosine-based SVM-RFE feature selection method for prostate histopathological grading.

    Science.gov (United States)

    Sahran, Shahnorbanun; Albashish, Dheeb; Abdullah, Azizi; Shukor, Nordashima Abd; Hayati Md Pauzi, Suria

    2018-04-18

    Feature selection (FS) methods are widely used in grading and diagnosing prostate histopathological images. In this context, FS is based on the texture features obtained from the lumen, nuclei, cytoplasm and stroma, all of which are important tissue components. However, it is difficult to represent the high-dimensional textures of these tissue components. To solve this problem, we propose a new FS method that enables the selection of features with minimal redundancy in the tissue components. We categorise tissue images based on the texture of individual tissue components via the construction of a single classifier and also construct an ensemble learning model by merging the values obtained by each classifier. Another issue that arises is overfitting due to the high-dimensional texture of individual tissue components. We propose a new FS method, SVM-RFE(AC), that integrates a Support Vector Machine-Recursive Feature Elimination (SVM-RFE) embedded procedure with an absolute cosine (AC) filter method to prevent redundancy in the selected features of the SV-RFE and an unoptimised classifier in the AC. We conducted experiments on H&E histopathological prostate and colon cancer images with respect to three prostate classifications, namely benign vs. grade 3, benign vs. grade 4 and grade 3 vs. grade 4. The colon benchmark dataset requires a distinction between grades 1 and 2, which are the most difficult cases to distinguish in the colon domain. The results obtained by both the single and ensemble classification models (which uses the product rule as its merging method) confirm that the proposed SVM-RFE(AC) is superior to the other SVM and SVM-RFE-based methods. We developed an FS method based on SVM-RFE and AC and successfully showed that its use enabled the identification of the most crucial texture feature of each tissue component. Thus, it makes possible the distinction between multiple Gleason grades (e.g. grade 3 vs. grade 4) and its performance is far superior to

  12. An optimized target-field method for MRI transverse biplanar gradient coil design

    International Nuclear Information System (INIS)

    Zhang, Rui; Xu, Jing; Huang, Kefu; Zhang, Jue; Fang, Jing; Fu, Youyi; Li, Yangjing

    2011-01-01

    Gradient coils are essential components of magnetic resonance imaging (MRI) systems. In this paper, we present an optimized target-field method for designing a transverse biplanar gradient coil with high linearity, low inductance and small resistance, which can well satisfy the requirements of permanent-magnet MRI systems. In this new method, the current density is expressed by trigonometric basis functions with unknown coefficients in polar coordinates. Following the standard procedures, we construct an objective function with respect to the total square errors of the magnetic field at all target-field points with the penalty items associated with the stored magnetic energy and the dissipated power. By adjusting the two penalty factors and minimizing the objective function, the appropriate coefficients of the current density are determined. Applying the stream function method to the current density, the specific winding patterns on the planes can be obtained. A novel biplanar gradient coil has been designed using this method to operate in a permanent-magnet MRI system. In order to verify the validity of the proposed approach, the gradient magnetic field generated by the resulted current density has been calculated via the Biot–Savart law. The results have demonstrated the effectiveness and advantage of this proposed method

  13. Optimization of DSC MRI Echo Times for CBV Measurements Using Error Analysis in a Pilot Study of High-Grade Gliomas.

    Science.gov (United States)

    Bell, L C; Does, M D; Stokes, A M; Baxter, L C; Schmainda, K M; Dueck, A C; Quarles, C C

    2017-09-01

    The optimal TE must be calculated to minimize the variance in CBV measurements made with DSC MR imaging. Simulations can be used to determine the influence of the TE on CBV, but they may not adequately recapitulate the in vivo heterogeneity of precontrast T2*, contrast agent kinetics, and the biophysical basis of contrast agent-induced T2* changes. The purpose of this study was to combine quantitative multiecho DSC MRI T2* time curves with error analysis in order to compute the optimal TE for a traditional single-echo acquisition. Eleven subjects with high-grade gliomas were scanned at 3T with a dual-echo DSC MR imaging sequence to quantify contrast agent-induced T2* changes in this retrospective study. Optimized TEs were calculated with propagation of error analysis for high-grade glial tumors, normal-appearing white matter, and arterial input function estimation. The optimal TE is a weighted average of the T2* values that occur as a contrast agent bolus transverses a voxel. The mean optimal TEs were 30.0 ± 7.4 ms for high-grade glial tumors, 36.3 ± 4.6 ms for normal-appearing white matter, and 11.8 ± 1.4 ms for arterial input function estimation (repeated-measures ANOVA, P optimal TE values for high-grade gliomas, and mean values of all 3 ROIs were statistically significant. The optimal TE for the arterial input function estimation is much shorter; this finding implies that quantitative DSC MR imaging acquisitions would benefit from multiecho acquisitions. In the case of a single-echo acquisition, the optimal TE prescribed should be 30-35 ms (without a preload) and 20-30 ms (with a standard full-dose preload). © 2017 by American Journal of Neuroradiology.

  14. Problem-Based Learning Method: Secondary Education 10th Grade Chemistry Course Mixtures Topic

    Science.gov (United States)

    Üce, Musa; Ates, Ismail

    2016-01-01

    In this research; aim was determining student achievement by comparing problem-based learning method with teacher-centered traditional method of teaching 10th grade chemistry lesson mixtures topic. Pretest-posttest control group research design is implemented. Research sample includes; two classes of (total of 48 students) an Anatolian High School…

  15. Nuclear fuel technology - Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

    International Nuclear Information System (INIS)

    2003-01-01

    This International Standard specifies a precise and accurate gravimetric method for determining the mass fraction of uranium in uranyl nitrate solutions of nuclear grade quality containing more than 100 g/kg of uranium. Non-volatile impurities influence the accuracy of the method

  16. A Mixed-Methods Study Investigating the Relationship between Media Multitasking Orientation and Grade Point Average

    Science.gov (United States)

    Lee, Jennifer

    2012-01-01

    The intent of this study was to examine the relationship between media multitasking orientation and grade point average. The study utilized a mixed-methods approach to investigate the research questions. In the quantitative section of the study, the primary method of statistical analyses was multiple regression. The independent variables for the…

  17. Differentiation of grade II/III and grade IV glioma by combining ''T1 contrast-enhanced brain perfusion imaging'' and susceptibility-weighted quantitative imaging

    International Nuclear Information System (INIS)

    Saini, Jitender; Gupta, Pradeep Kumar; Gupta, Rakesh Kumar; Sahoo, Prativa; Singh, Anup; Patir, Rana; Ahlawat, Suneeta; Beniwal, Manish; Thennarasu, K.; Santosh, Vani

    2018-01-01

    MRI is a useful method for discriminating low- and high-grade glioma using perfusion MRI and susceptibility-weighted imaging (SWI). The purpose of this study is to evaluate the usefulness of T1-perfusion MRI and SWI in discriminating among grade II, III, and IV gliomas. T1-perfusion MRI was used to measure relative cerebral blood volume (rCBV) in 129 patients with glioma (70 grade IV, 33 grade III, and 26 grade II tumors). SWI was also used to measure the intratumoral susceptibility signal intensity (ITSS) scores for each tumor in these patients. rCBV and ITSS values were compared to seek differences between grade II vs. grade III, grade III vs. grade IV, and grade III+II vs. grade IV tumors. Significant differences in rCBV values of the three grades of the tumors were noted and pairwise comparisons showed significantly higher rCBV values in grade IV tumors as compared to grade III tumors, and similarly increased rCBV was seen in the grade III tumors as compared to grade II tumors (p < 0.001). Grade IV gliomas showed significantly higher ITSS scores on SWI as compared to grade III tumors (p < 0.001) whereas insignificant difference was seen on comparing ITSS scores of grade III with grade II tumors. Combining the rCBV and ITSS resulted in significant improvement in the discrimination of grade III from grade IV tumors. The combination of rCBV values derived from T1-perfusion MRI and SWI derived ITSS scores improves the diagnostic accuracy for discrimination of grade III from grade IV gliomas. (orig.)

  18. Differentiation of grade II/III and grade IV glioma by combining ''T1 contrast-enhanced brain perfusion imaging'' and susceptibility-weighted quantitative imaging

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Jitender [National Institute of Mental Health and Neurosciences, Neuroimaging and Interventional Radiology, Bangalore (India); Gupta, Pradeep Kumar; Gupta, Rakesh Kumar [Fortis Memorial Research Institute, Department of Radiology and Imaging, Gurugram (India); Sahoo, Prativa [Philips Health System, Philips India Limited, Bangalore (India); Beckman Research Institute, Mathematical Oncology, Duarte, CA (United States); Singh, Anup [Indian Institute of Technology Delhi, Center for Biomedical Engineering, Delhi (India); Patir, Rana [Fortis Memorial Research Institute, Department of Neurosurgery, Gurugram (India); Ahlawat, Suneeta [Fortis Memorial Research Institute, SRL Diagnostics, Gurugram (India); Beniwal, Manish [National Institute of Mental Health and Neurosciences, Department of Neurosurgery, Bangalore (India); Thennarasu, K. [National Institute of Mental Health and Neurosciences, Department of Biostatistics, Bangalore (India); Santosh, Vani [National Institute of Mental Health and Neurosciences, Department of Neuropathology, Bangalore (India)

    2018-01-15

    MRI is a useful method for discriminating low- and high-grade glioma using perfusion MRI and susceptibility-weighted imaging (SWI). The purpose of this study is to evaluate the usefulness of T1-perfusion MRI and SWI in discriminating among grade II, III, and IV gliomas. T1-perfusion MRI was used to measure relative cerebral blood volume (rCBV) in 129 patients with glioma (70 grade IV, 33 grade III, and 26 grade II tumors). SWI was also used to measure the intratumoral susceptibility signal intensity (ITSS) scores for each tumor in these patients. rCBV and ITSS values were compared to seek differences between grade II vs. grade III, grade III vs. grade IV, and grade III+II vs. grade IV tumors. Significant differences in rCBV values of the three grades of the tumors were noted and pairwise comparisons showed significantly higher rCBV values in grade IV tumors as compared to grade III tumors, and similarly increased rCBV was seen in the grade III tumors as compared to grade II tumors (p < 0.001). Grade IV gliomas showed significantly higher ITSS scores on SWI as compared to grade III tumors (p < 0.001) whereas insignificant difference was seen on comparing ITSS scores of grade III with grade II tumors. Combining the rCBV and ITSS resulted in significant improvement in the discrimination of grade III from grade IV tumors. The combination of rCBV values derived from T1-perfusion MRI and SWI derived ITSS scores improves the diagnostic accuracy for discrimination of grade III from grade IV gliomas. (orig.)

  19. Bone marrow MRI in patients with myelodysplastic syndromes

    International Nuclear Information System (INIS)

    Chen Zhao; Guo You; Wang Renfa; Zou Mingli; Liu Wenli; Xia Liming; Wang Chengyuan

    2004-01-01

    Objective: To observe the MR imaging of bone marrow in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), and to reveal the rule of bone marrow infiltration and the role of MRI in diagnosing and predicting the prognosis of myelodysplastic syndromes. Methods: Thirty patients received MRI after the diagnosis based on clinic and FAB subtype study, including 16 with MDS and 14 with AML. MR image was obtained by T 1 -weighted spin echo and shot time inversion recovery in pelvis and femur. The examining results of morphology and blood routine were collected at the same time. 30 age-matched volunteers were selected as controls. Results: The MRI appearance was classified into their patterns based on scope of focus. MRI patterns from grade 1 to grade 3 was observed in patients with MDS. All patients with AML distributed in grade 2 to grade 3. The distribution of patterns had no significant difference between MDS and AML (P>0.05). The marrow ratio had significant difference among MDS, AML, and controls (P<0.05). The MRI grade was consistent with the clinic diagnostic indexes. Conclusion: MRI can provide a better understanding of the difference between MDS and AML. MRI can estimate the extent of disease in the marrow as a whole. MRI of bone marrow can provide imaging basis in diagnosis and predicting the prognosis for patients with MDS

  20. Fat saturation in dynamic breast MRI at 3 Tesla: is the Dixon technique superior to spectral fat saturation? A visual grading characteristics study

    Energy Technology Data Exchange (ETDEWEB)

    Clauser, P. [University of Udine, Azienda Ospedaliero-Universitaria ' ' S.Maria della Misericordia' ' , Institute of Diagnostic Radiology, Udine (Italy); Medical University of Vienna, Department of Biomedical Imaging and Image-guided interventions, Division of Molecular and Gender Imaging, Vienna (Austria); Pinker, K.; Helbich, T.H.; Kapetas, P.; Bernathova, M.; Baltzer, P.A.T. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided interventions, Division of Molecular and Gender Imaging, Vienna (Austria)

    2014-09-15

    To intra-individually compare the diagnostic image quality of Dixon and spectral fat suppression at 3 T. Fifty consecutive patients (mean age 55.1 years) undergoing 3 T breast MRI were recruited for this prospective study. The image protocol included pre-contrast and delayed post-contrast spectral and Dixon fat-suppressed T1w series. Two independent blinded readers compared spectral and Dixon fat-suppressed series by evaluating six ordinal (1 worst to 5 best) image quality criteria (image quality, delineation of anatomical structures, fat suppression in the breast and axilla, lesion delineation and internal enhancement). Breast density and size were assessed. Data analysis included Spearman's rank correlation coefficient and visual grading characteristics (VGC) analysis. Four examinations were excluded; 48 examinations in 46 patients were evaluated. In VGC analysis, the Dixon technique was superior regarding image quality criteria analysed (P < 0.01). Smaller breast size and lower breast density were significantly (P < 0.01) correlated with impaired spectral fat suppression quality. No such correlation was identified for the Dixon technique, which showed reconstruction-based water-fat mixups leading to insufficient image quality in 20.8 %. The Dixon technique outperformed spectral fat suppression in all evaluated criteria (P < 0.01). Non-diagnostic examinations can be avoided by fat and water image reconstruction. The superior image quality of the Dixon technique can improve breast MRI interpretation. (orig.)

  1. Automatic segmentation of MRI head images by 3-D region growing method which utilizes edge information

    International Nuclear Information System (INIS)

    Jiang, Hao; Suzuki, Hidetomo; Toriwaki, Jun-ichiro

    1991-01-01

    This paper presents a 3-D segmentation method that automatically extracts soft tissue from multi-sliced MRI head images. MRI produces a sequence of two-dimensional (2-D) images which contains three-dimensional (3-D) information of organs. To utilize such information we need effective algorithms to treat 3-D digital images and to extract organs and tissues of interest. We developed a method to extract the brain from MRI images which uses a region growing procedure and integrates information of uniformity of gray levels and information of the presence of edge segments in the local area around the pixel of interest. First we generate a kernel region which is a part of brain tissue by simple thresholding. Then we grow the region by means of a region growing algorithm under the control of 3-D edge existence to obtain the region of the brain. Our method is rather simple because it uses basic 3-D image processing techniques like spatial difference. It is robust for variation of gray levels inside a tissue since it also refers to the edge information in the process of region growing. Therefore, the method is flexible enough to be applicable to the segmentation of other images including soft tissues which have complicated shapes and fluctuation in gray levels. (author)

  2. Multiparametric MRI of the prostate. Method for early detection of prostate cancer?

    International Nuclear Information System (INIS)

    Schlemmer, Heinz-Peter

    2010-01-01

    Current approaches for the early detection of prostate cancer are controversially discussed because the disease is characterized by a high incidence rate with a relatively low morbidity rate, availability of only limited prognostic markers, and continued therapy-related morbidity. Conventional morphological MRI does not play a role in early detection since small tumor foci cannot be delineated. However, if there is clinical suspicion for prostate cancer, multiparametric MRI is currently the most accurate method for detecting and characterizing suspicious lesions in the prostate. The potential to identify the so-called 'index lesion', i.e., the tumor area that is most aggressive and determines treatment, is particularly important. This information can increase the accuracy of prostate biopsy and serve as a biomarker for follow-up during active surveillance. The method may considerably contribute to the urgently required separation of clinically significant from clinically insignificant prostate cancers. (orig.)

  3. Signal to noise comparison of metabolic imaging methods on a clinical 3T MRI

    DEFF Research Database (Denmark)

    Müller, C. A.; Hansen, Rie Beck; Skinner, J. G.

    MRI with hyperpolarized tracers has enabled new diagnostic applications, e.g. metabolic imaging in cancer research. However, the acquisition of the transient, hyperpolarized signal with spatial and frequency resolution requires dedicated imaging methods. Here, we compare three promising candidate...... for 2D MR spectroscopic imaging (MRSI): (i) multi-echo balanced steady-state free precession (me-bSSFP), 1,2 (ii) echo planar spectroscopic imaging (EPSI) sequence and (iii) phase-encoded, pulseacquisition chemical-shift imaging (CSI)...

  4. Mixing studies at low grade vacuum pan using the radiotracer method

    International Nuclear Information System (INIS)

    Griffith, J.M

    1999-01-01

    In this paper, some preliminary results achieved in the evaluation of the homogenization time at a vacuum pan for massecuite b and seed preparation , using two approaches of the radiotracer method, are presented. Practically no difference between the o n line , using small size detector and the sampling methods, in mixing studies performed at the high-grade massecuite was detected. Results achieved during the trials performed at the vacuum station show that the mechanical agitation in comparison with normal agitation improves the performance of mixing in high-grade massecuite b and in seed preparation at the vacuum pan

  5. Mixing studies at low grade vacuum pan using the radiotracer method

    International Nuclear Information System (INIS)

    Griffith, J.M

    1999-01-01

    In this paper, some preliminary results achieved in the evaluation of the homogenization time at a Vacuum Pan for massecuite B and seed preparation , using two approaches of the radiotracer method, are presented. Practically no difference between the Ion Line , using small size detector and the sampling methods, in mixing studies performed at the high-grade massecuite was detected. Results achieved during the trials performed at the vacuum station show that the mechanical agitation in comparison with normal agitation improves the performance of mixing in high-grade massecuite b and in seed preparation at the vacuum pan

  6. Supervised methods for detection and segmentation of tissues in clinical lumbar MRI.

    Science.gov (United States)

    Ghosh, Subarna; Chaudhary, Vipin

    2014-10-01

    Lower back pain (LBP) is widely prevalent all over the world and more than 80% of the people suffer from LBP at some point of their lives. Moreover, a shortage of radiologists is the most pressing cause for the need of CAD (computer-aided diagnosis) systems. Automatic localization and labeling of intervertebral discs from lumbar MRI is the first step towards computer-aided diagnosis of lower back ailments. Subsequently, for diagnosis and characterization (quantification and localization) of abnormalities like disc herniation and stenosis, a completely automatic segmentation of intervertebral discs and the dural sac is extremely important. Contribution of this paper towards clinical CAD systems is two-fold. First, we propose a method to automatically detect all visible intervertebral discs in clinical sagittal MRI using heuristics and machine learning techniques. We provide a novel end-to-end framework that outputs a tight bounding box for each disc, instead of simply marking the centroid of discs, as has been the trend in the recent past. Second, we propose a method to simultaneously segment all the tissues (vertebrae, intervertebral disc, dural sac and background) in a lumbar sagittal MRI, using an auto-context approach instead of any explicit shape features or models. Past work tackles the lumbar segmentation problem on a tissue/organ basis, and which tend to perform poorly in clinical scans due to high variability in appearance. We, on the other hand, train a series of robust classifiers (random forests) using image features and sparsely sampled context features, which implicitly represent the shape and configuration of the image. Both these methods have been tested on a huge clinical dataset comprising of 212 cases and show very promising results for both disc detection (98% disc localization accuracy and 2.08mm mean deviation) and sagittal MRI segmentation (dice similarity indices of 0.87 and 0.84 for the dural sac and the inter-vertebral disc, respectively

  7. Corticospinal MRI tractography in space-occupying brain lesions by diffusion tensor and kurtosis imaging methods

    Energy Technology Data Exchange (ETDEWEB)

    Leote, Joao [epartment of Neurosurgery, Hospital Garcia de Orta, Almada (Portugal); Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon, Lisboa (Portugal); Nunes, Rita; Cerqueira, Luis; Ferreira, Hugo Alexandre [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon, Lisboa (Portugal)

    2015-05-18

    Recently, DKI-based tractography has been developed, showing improved crossing-fiber resolution in comparison to deterministic DTI-based tractography in healthy subjects. In this work, DTI and DKI-based tractography methods were compared regarding the assessment of the corticospinal tract in patients presenting space-occupying brain lesions near cortical motor areas. Nine patients (4 males) aged 23 to 62 years old, with space-occupying brain lesions (e.g. tumors) were studied for pre-surgical planning using a 1.5T MRI scanner and a 12-channel head coil. In 5 patients diffusion data was acquired along 64 directions and in 4 patients along 32 directions both with b-values 0, 1000 and 2000 s/mm2. Corticospinal tracts were estimated using deterministic DTI and DKI methods and also using probabilistic DTI. The superior cerebellar peduncles and the motor cortical areas, ipsilateral and contralateral to the lesions, were used as seed regions-of-interest for fiber tracking. Tracts courses and volumes were documented and compared between methods. Results showed that it was possible to estimate fiber tracts using deterministic DTI and DKI methods in 8/9 patients, and using the probabilistic DTI method in all patients. Overall, it was observed that DKI-based tractography showed more voluminous fiber tracts than when using deterministic DTI. The DKI method also showed curvilinear fibers mainly above lesions margins, which were not visible with deterministic DTI in 5 patients. Similar tracts were observed when using probabilistic DTI in 3 of those patients. Results suggest that the DKI method contribute with additional information about the corticospinal tract course in comparison with the DTI method, especially with subcortical lesions and near lesions’ margins. Therefore, this study suggests that DKI-based tractography could be useful in MRI and hybrid PET-MRI pre-surgical planning protocols for improved corticospinal tract evaluation.

  8. New hallmark of hepatocellular carcinoma, early hepatocellular carcinoma and high-grade dysplastic nodules on Gd-EOB-DTPA MRI in patients with cirrhosis: a new diagnostic algorithm.

    Science.gov (United States)

    Renzulli, Matteo; Biselli, Maurizio; Brocchi, Stefano; Granito, Alessandro; Vasuri, Francesco; Tovoli, Francesco; Sessagesimi, Elisa; Piscaglia, Fabio; D'Errico, Antonietta; Bolondi, Luigi; Golfieri, Rita

    2018-02-03

    Many improvements have been made in diagnosing hepatocellular carcinoma (HCC), but the radiological hallmarks of HCC have remained the same for many years. We prospectively evaluated the imaging criteria of HCC, early HCC and high-grade dysplastic nodules (HGDNs) in patients under surveillance for chronic liver disease, using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) MRI and diffusion-weighted imaging. Our study population included 420 nodules >1 cm in 228 patients. The MRI findings of each nodule were collected in all sequences/phases. The diagnosis of HCC was made according to the American Association for the Study of Liver Diseases (AASLD) criteria; all atypical nodules were diagnosed using histology. A classification and regression tree was developed using three MRI findings which were independently significant correlated variables for early HCC/HCC, and the best sequence of their application in a new diagnostic algorithm (hepatobiliary hypointensity, arterial hyperintensity and diffusion restriction) was suggested. This algorithm demonstrated, both in the entire study population and for nodules ≤2 cm, higher sensitivity (96% [95% CI 93.5% to 97.6%] and 96.6% [95% CI 93.9% to 98.5%], P<0.001, respectively) and slightly lower specificity (91.8% [95% CI 88.6% to 94.1%], P=0.063, and 92.7% [95% CI 88.9% to 95.4%], P=0.125, respectively) than those of the AASLD criteria. Our new diagnostic algorithm also showed a very high sensitivity (94.7%; 95% CI 92% to 96.6%) and specificity (99.3%; 95% CI 97.7% to 99.8%) in classifying HGDN. Our new diagnostic algorithm demonstrated significantly higher sensitivity and comparable specificity than those of the AASLD imaging criteria for HCC in patients with cirrhosis evaluated using Gd-EOB-DTPA MRI, even for lesions ≤2 cm. Moreover, this diagnostic algorithm allowed evaluating other lesions which could arise in a cirrhotic liver, such as early HCC and HGDN. © Article author

  9. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  10. MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain

    International Nuclear Information System (INIS)

    Eide, Per Kristian; Ringstad, Geir

    2015-01-01

    Recently, the “glymphatic system” of the brain has been discovered in rodents, which is a paravascular, transparenchymal route for clearance of excess brain metabolites and distribution of compounds in the cerebrospinal fluid. It has already been demonstrated that intrathecally administered gadolinium (Gd) contrast medium distributes along this route in rats, but so far not in humans. A 27-year-old woman underwent magnetic resonance imaging (MRI) with intrathecal administration of gadobutrol, which distributed throughout her entire brain after 1 and 4.5 h. MRI with intrathecal Gd may become a tool to study glymphatic function in the human brain

  11. MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain.

    Science.gov (United States)

    Eide, Per Kristian; Ringstad, Geir

    2015-11-01

    Recently, the "glymphatic system" of the brain has been discovered in rodents, which is a paravascular, transparenchymal route for clearance of excess brain metabolites and distribution of compounds in the cerebrospinal fluid. It has already been demonstrated that intrathecally administered gadolinium (Gd) contrast medium distributes along this route in rats, but so far not in humans. A 27-year-old woman underwent magnetic resonance imaging (MRI) with intrathecal administration of gadobutrol, which distributed throughout her entire brain after 1 and 4.5 h. MRI with intrathecal Gd may become a tool to study glymphatic function in the human brain.

  12. MRI of the Chest

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

  13. Application of ADC measurement in characterization of renal cell carcinomas with different pathological types and grades by 3.0 T diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaoduo, E-mail: yxd98@yahoo.com.cn [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Lin, Meng, E-mail: linmeng77xp@yahoo.com.cn [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Ouyang, Han, E-mail: hbybj@sohu.com [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhou, Chunwu, E-mail: cjr.zhouchunwu@163.vip.com [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhang, Hongtu, E-mail: zhanghongtu1010@yahoo.com.cn [Department of Pathology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China)

    2012-11-15

    Purpose: To test the feasibility of apparent diffusion coefficient (ADC) value obtained with 3.0 T diffusion-weighted imaging (DWI) in the characterization of renal cell carcinomas (RCC) with different pathological subtypes and grades. Materials and methods: A total of 137 patients who were diagnosed with RCC and underwent DWI were included in this study. The diagnosis was confirmed by pathological examination of surgical specimens. Images of DWI were obtained with b values of 0 and 800 s/mm{sup 2}. The ADC values in the solid area of tumors and in the corresponding regions of contralateral normal renal parenchyma were measured and analyzed statistically. Results: The mean ADC value was significantly lower in RCC (1.381 {+-} 0.444 Multiplication-Sign 10{sup -3} mm{sup 2}/s) than in normal renal parenchyma (2.232 {+-} 0.221 Multiplication-Sign 10{sup -3} mm{sup 2}/s) (P < 0.001). The ADC value was also statistically different between clear cell RCC (CCRCC) and non-CCRCC, and between different grades of CCRCC except grade I vs II and grade III vs IV. Conclusion: ADC measurement on 3.0 T DWI provides useful information in diagnostic work-up of RCC in terms of differentiation of RCC and normal renal parenchyma, and characterization of RCC with different pathological subtypes and grades.

  14. Hybrid finite volume/ finite element method for radiative heat transfer in graded index media

    Science.gov (United States)

    Zhang, L.; Zhao, J. M.; Liu, L. H.; Wang, S. Y.

    2012-09-01

    The rays propagate along curved path determined by the Fermat principle in the graded index medium. The radiative transfer equation in graded index medium (GRTE) contains two specific redistribution terms (with partial derivatives to the angular coordinates) accounting for the effect of the curved ray path. In this paper, the hybrid finite volume with finite element method (hybrid FVM/FEM) (P.J. Coelho, J. Quant. Spectrosc. Radiat. Transf., vol. 93, pp. 89-101, 2005) is extended to solve the radiative heat transfer in two-dimensional absorbing-emitting-scattering graded index media, in which the spatial discretization is carried out using a FVM, while the angular discretization is by a FEM. The FEM angular discretization is demonstrated to be preferable in dealing with the redistribution terms in the GRTE. Two stiff matrix assembly schemes of the angular FEM discretization, namely, the traditional assembly approach and a new spherical assembly approach (assembly on the unit sphere of the solid angular space), are discussed. The spherical assembly scheme is demonstrated to give better results than the traditional assembly approach. The predicted heat flux distributions and temperature distributions in radiative equilibrium are determined by the proposed method and compared with the results available in other references. The proposed hybrid FVM/FEM method can predict the radiative heat transfer in absorbing-emitting-scattering graded index medium with good accuracy.

  15. Hybrid finite volume/ finite element method for radiative heat transfer in graded index media

    International Nuclear Information System (INIS)

    Zhang, L.; Zhao, J.M.; Liu, L.H.; Wang, S.Y.

    2012-01-01

    The rays propagate along curved path determined by the Fermat principle in the graded index medium. The radiative transfer equation in graded index medium (GRTE) contains two specific redistribution terms (with partial derivatives to the angular coordinates) accounting for the effect of the curved ray path. In this paper, the hybrid finite volume with finite element method (hybrid FVM/FEM) (P.J. Coelho, J. Quant. Spectrosc. Radiat. Transf., vol. 93, pp. 89-101, 2005) is extended to solve the radiative heat transfer in two-dimensional absorbing-emitting-scattering graded index media, in which the spatial discretization is carried out using a FVM, while the angular discretization is by a FEM. The FEM angular discretization is demonstrated to be preferable in dealing with the redistribution terms in the GRTE. Two stiff matrix assembly schemes of the angular FEM discretization, namely, the traditional assembly approach and a new spherical assembly approach (assembly on the unit sphere of the solid angular space), are discussed. The spherical assembly scheme is demonstrated to give better results than the traditional assembly approach. The predicted heat flux distributions and temperature distributions in radiative equilibrium are determined by the proposed method and compared with the results available in other references. The proposed hybrid FVM/FEM method can predict the radiative heat transfer in absorbing-emitting-scattering graded index medium with good accuracy.

  16. 3D MRI of the colon: methods and first results of 5 patients

    International Nuclear Information System (INIS)

    Luboldt, W.; Bauerfeind, P.; Pelkonen, P.; Steiner, P.; Krestin, G.P.; Debatin, J.F.

    1997-01-01

    Purpose: 'Exoscopic' and endoscopic identification of colorectal pathologies via MRI. Methods: 5 patients (36-88 years), two normal and three with different colorectal pathologies (diverticular disease, polyps and carcinoma of the colon), were examined by MRI after colonoscopy. Subsequent to filling of the colon with a gadolinium-water mixture under MRI-monitoring, 3D-data sets of the colon were acquired in prone and supine positions over a 28 sec breathold interval. Subsequently multiplanar T 1 -weighted 2D-sequences were acquired before and following i.v. administration of Gd-DTPA (0.1 mmol/kg BW). All imaging was performed in the coronal orientation. The 3D-data were interactively analysed based on various displays: Maximum intensity projection (MIP), surface shadowed display (SSD), multiplanar reconstruction (MPR), virtual colonoscopy (VC). Results: All of the colorectal pathologies could be interactively diagnosed by MPR. On MIP images some pathologies were missed. VC presented the morphology of colon haustra as well as of all endoluminally growing lesions in a manner similar to endoscopy. The colon masses showed uptake of contrast media and could thus be differentiated from air or faeces. (orig./AJ) [de

  17. An innovative jet boring mining method available for the high grade uranium ore underground deposits

    International Nuclear Information System (INIS)

    Narcy, J.L.

    1996-01-01

    An innovative mining method, based on the capability of a high pressure water jet to desaggregate rock, has been conceived and tested with success at the highest grade uranium ore deposit in the world, the Cigar Lake deposit in Saskatchewan, Canada. 113 tonnes of ore at 13% U were mined out by a new jet-boring mining method operated on a semi-industrial basis, in 1992 during the test mining program of Cigar Lake Project. (author). 9 figs

  18. Hybrid ICA-Seed-Based Methods for fMRI Functional Connectivity Assessment: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    Robert E. Kelly

    2010-01-01

    Full Text Available Brain functional connectivity (FC is often assessed from fMRI data using seed-based methods, such as those of detecting temporal correlation between a predefined region (seed and all other regions in the brain; or using multivariate methods, such as independent component analysis (ICA. ICA is a useful data-driven tool, but reproducibility issues complicate group inferences based on FC maps derived with ICA. These reproducibility issues can be circumvented with hybrid methods that use information from ICA-derived spatial maps as seeds to produce seed-based FC maps. We report results from five experiments to demonstrate the potential advantages of hybrid ICA-seed-based FC methods, comparing results from regressing fMRI data against task-related a priori time courses, with “back-reconstruction” from a group ICA, and with five hybrid ICA-seed-based FC methods: ROI-based with (1 single-voxel, (2 few-voxel, and (3 many-voxel seed; and dual-regression-based with (4 single ICA map and (5 multiple ICA map seed.

  19. Hepatobiliary phase images using gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced MRI as an imaging surrogate for the albumin–bilirubin grading system

    Energy Technology Data Exchange (ETDEWEB)

    Takatsu, Yasuo, E-mail: pcblue2@yahoo.co.jp [Department of Radiology, Osaka Red Cross Hospital, 5-30 Fudegasaki, Tennouji-ku, Osaka, 543-8555 (Japan); Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 (Japan); Kobayashi, Satoshi, E-mail: satoshik@staff.kanazawa-u.ac.jp [Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 (Japan); Miyati, Tosiaki, E-mail: ramiyati@mhs.mp.kanazawa-u.ac.jp [Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 (Japan); Shiozaki, Toshiki, E-mail: shiozaki.toshiki@gmail.com [Department of Radiology, Osaka Red Cross Hospital, 5-30 Fudegasaki, Tennouji-ku, Osaka, 543-8555 (Japan)

    2016-12-15

    Objectives: To clarify the correlation between hepatobiliary phase (HBP) images using gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) and albumin–bilirubin (ALBI) grading system. Materials and methods: We evaluated 220 consecutive patients who underwent liver magnetic resonance imaging with Gd-EOB-DTPA. Quantitative liver–spleen contrast ratio (Q-LSC) was calculated in HBP images approximately 20 min after Gd-EOB-DTPA administration. To evaluate the degree of association between Q-LSC and ALBI grade, the Child–Pugh (C-P) score was used for comparison. Correlation coefficients were calculated, and median Q-LSC values were compared with the C-P scores and ALBI grades. The Steel–Dwass multiple comparison test was used for statistical analysis. Results: The correlation coefficient between Q-LSC and C-P score was −0.35, P < 0.0001, and the ALBI grade was −0.61, P < 0.0001. Q-LSC of overall median, C-P A, B, and C were 1.94, 1.91, 1.96, and 1.33, respectively. The differences between C-P A and C-P B, C-P B and C-P C, and C-P A and C-P C were P = 0.999, 0.126, and 0.149, respectively. Q-LSC of the overall median, ALBI grade 1, 2, and 3 were 1.94, 2.12, 1.69, and 1.30, respectively. The differences between ALBI grades 1 and 2, 2 and 3, and 1 and 3 were P < 0.0001, P = 0.0466, and P = 0.0035, respectively. Q-LSC was better correlated and discriminated by ALBI grade than C-P score. Conclusion: A strong correlation was observed between Q-LSC of an HBP image with Gd-EOB-DTPA and ALBI grade; HBP imaging could be a surrogate for the ALBI grade.

  20. Efficient method to design RF pulses for parallel excitation MRI using gridding and conjugate gradient.

    Science.gov (United States)

    Feng, Shuo; Ji, Jim

    2014-04-01

    Parallel excitation (pTx) techniques with multiple transmit channels have been widely used in high field MRI imaging to shorten the RF pulse duration and/or reduce the specific absorption rate (SAR). However, the efficiency of pulse design still needs substantial improvement for practical real-time applications. In this paper, we present a detailed description of a fast pulse design method with Fourier domain gridding and a conjugate gradient method. Simulation results of the proposed method show that the proposed method can design pTx pulses at an efficiency 10 times higher than that of the conventional conjugate-gradient based method, without reducing the accuracy of the desirable excitation patterns.

  1. A brain MRI bias field correction method created in the Gaussian multi-scale space

    Science.gov (United States)

    Chen, Mingsheng; Qin, Mingxin

    2017-07-01

    A pre-processing step is needed to correct for the bias field signal before submitting corrupted MR images to such image-processing algorithms. This study presents a new bias field correction method. The method creates a Gaussian multi-scale space by the convolution of the inhomogeneous MR image with a two-dimensional Gaussian function. In the multi-Gaussian space, the method retrieves the image details from the differentiation of the original image and convolution image. Then, it obtains an image whose inhomogeneity is eliminated by the weighted sum of image details in each layer in the space. Next, the bias field-corrected MR image is retrieved after the Υ correction, which enhances the contrast and brightness of the inhomogeneity-eliminated MR image. We have tested the approach on T1 MRI and T2 MRI with varying bias field levels and have achieved satisfactory results. Comparison experiments with popular software have demonstrated superior performance of the proposed method in terms of quantitative indices, especially an improvement in subsequent image segmentation.

  2. Using multivariate machine learning methods and structural MRI to classify childhood onset schizophrenia and healthy controls

    Directory of Open Access Journals (Sweden)

    Deanna eGreenstein

    2012-06-01

    Full Text Available Introduction: Multivariate machine learning methods can be used to classify groups of schizophrenia patients and controls using structural magnetic resonance imaging (MRI. However, machine learning methods to date have not been extended beyond classification and contemporaneously applied in a meaningful way to clinical measures. We hypothesized that brain measures would classify groups, and that increased likelihood of being classified as a patient using regional brain measures would be positively related to illness severity, developmental delays and genetic risk. Methods: Using 74 anatomic brain MRI sub regions and Random Forest, we classified 98 COS patients and 99 age, sex, and ethnicity-matched healthy controls. We also used Random Forest to determine the likelihood of being classified as a schizophrenia patient based on MRI measures. We then explored relationships between brain-based probability of illness and symptoms, premorbid development, and presence of copy number variation associated with schizophrenia. Results: Brain regions jointly classified COS and control groups with 73.7% accuracy. Greater brain-based probability of illness was associated with worse functioning (p= 0.0004 and fewer developmental delays (p=0.02. Presence of copy number variation (CNV was associated with lower probability of being classified as schizophrenia (p=0.001. The regions that were most important in classifying groups included left temporal lobes, bilateral dorsolateral prefrontal regions, and left medial parietal lobes. Conclusions: Schizophrenia and control groups can be well classified using Random Forest and anatomic brain measures, and brain-based probability of illness has a positive relationship with illness severity and a negative relationship with developmental delays/problems and CNV-based risk.

  3. A Hybrid Machine Learning Method for Fusing fMRI and Genetic Data: Combining both Improves Classification of Schizophrenia

    Directory of Open Access Journals (Sweden)

    Honghui Yang

    2010-10-01

    Full Text Available We demonstrate a hybrid machine learning method to classify schizophrenia patients and healthy controls, using functional magnetic resonance imaging (fMRI and single nucleotide polymorphism (SNP data. The method consists of four stages: (1 SNPs with the most discriminating information between the healthy controls and schizophrenia patients are selected to construct a support vector machine ensemble (SNP-SVME. (2 Voxels in the fMRI map contributing to classification are selected to build another SVME (Voxel-SVME. (3 Components of fMRI activation obtained with independent component analysis (ICA are used to construct a single SVM classifier (ICA-SVMC. (4 The above three models are combined into a single module using a majority voting approach to make a final decision (Combined SNP-fMRI. The method was evaluated by a fully-validated leave-one-out method using 40 subjects (20 patients and 20 controls. The classification accuracy was: 0.74 for SNP-SVME, 0.82 for Voxel-SVME, 0.83 for ICA-SVMC, and 0.87 for Combined SNP-fMRI. Experimental results show that better classification accuracy was achieved by combining genetic and fMRI data than using either alone, indicating that genetic and brain function representing different, but partially complementary aspects, of schizophrenia etiopathology. This study suggests an effective way to reassess biological classification of individuals with schizophrenia, which is also potentially useful for identifying diagnostically important markers for the disorder.

  4. TU-AB-BRA-09: A Novel Method of Generating Ultrafast Volumetric Cine MRI (VC-MRI) Using Prior 4D-MRI and On-Board Phase-Skipped Encoding Acquisition for Radiotherapy Target Localization

    International Nuclear Information System (INIS)

    Wang, C; Yin, F; Harris, W; Cai, J; Chang, Z; Ren, L

    2016-01-01

    Purpose: To develop a technique generating ultrafast on-board VC-MRI using prior 4D-MRI and on-board phase-skipped encoding k-space acquisition for real-time 3D target tracking of liver and lung radiotherapy. Methods: The end-of-expiration (EOE) volume in 4D-MRI acquired during the simulation was selected as the prior volume. 3 major respiratory deformation patterns were extracted through the principal component analysis of the deformation field maps (DFMs) generated between EOE and all other phases. The on-board VC-MRI at each instant was considered as a deformation of the prior volume, and the deformation was modeled as a linear combination of the extracted 3 major deformation patterns. To solve the weighting coefficients of the 3 major patterns, a 2D slice was extracted from VC-MRI volume to match with the 2D on-board sampling data, which was generated by 8-fold phase skipped-encoding k-space acquisition (i.e., sample 1 phase-encoding line out of every 8 lines) to achieve an ultrafast 16–24 volumes/s frame rate. The method was evaluated using XCAT digital phantom to simulate lung cancer patients. The 3D volume of end-ofinhalation (EOI) phase at the treatment day was used as ground-truth onboard VC-MRI with simulated changes in 1) breathing amplitude and 2) breathing amplitude/phase change from the simulation day. A liver cancer patient case was evaluated for in-vivo feasibility demonstration. Results: The comparison between ground truth and estimated on-board VC-MRI shows good agreements. In XCAT study with changed breathing amplitude, the volume-percent-difference(VPD) between ground-truth and estimated tumor volumes at EOI was 6.28% and the Center-of-Mass-Shift(COMS) was 0.82mm; with changed breathing amplitude and phase, the VPD was 8.50% and the COMS was 0.54mm. The study of liver patient case also demonstrated a promising in vivo feasibility of the proposed method Conclusion: Preliminary results suggest the feasibility to estimate ultrafast VC-MRI for on

  5. TU-AB-BRA-09: A Novel Method of Generating Ultrafast Volumetric Cine MRI (VC-MRI) Using Prior 4D-MRI and On-Board Phase-Skipped Encoding Acquisition for Radiotherapy Target Localization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C; Yin, F; Harris, W; Cai, J; Chang, Z; Ren, L [Duke University Medical Center, Durham, NC (United States)

    2016-06-15

    Purpose: To develop a technique generating ultrafast on-board VC-MRI using prior 4D-MRI and on-board phase-skipped encoding k-space acquisition for real-time 3D target tracking of liver and lung radiotherapy. Methods: The end-of-expiration (EOE) volume in 4D-MRI acquired during the simulation was selected as the prior volume. 3 major respiratory deformation patterns were extracted through the principal component analysis of the deformation field maps (DFMs) generated between EOE and all other phases. The on-board VC-MRI at each instant was considered as a deformation of the prior volume, and the deformation was modeled as a linear combination of the extracted 3 major deformation patterns. To solve the weighting coefficients of the 3 major patterns, a 2D slice was extracted from VC-MRI volume to match with the 2D on-board sampling data, which was generated by 8-fold phase skipped-encoding k-space acquisition (i.e., sample 1 phase-encoding line out of every 8 lines) to achieve an ultrafast 16–24 volumes/s frame rate. The method was evaluated using XCAT digital phantom to simulate lung cancer patients. The 3D volume of end-ofinhalation (EOI) phase at the treatment day was used as ground-truth onboard VC-MRI with simulated changes in 1) breathing amplitude and 2) breathing amplitude/phase change from the simulation day. A liver cancer patient case was evaluated for in-vivo feasibility demonstration. Results: The comparison between ground truth and estimated on-board VC-MRI shows good agreements. In XCAT study with changed breathing amplitude, the volume-percent-difference(VPD) between ground-truth and estimated tumor volumes at EOI was 6.28% and the Center-of-Mass-Shift(COMS) was 0.82mm; with changed breathing amplitude and phase, the VPD was 8.50% and the COMS was 0.54mm. The study of liver patient case also demonstrated a promising in vivo feasibility of the proposed method Conclusion: Preliminary results suggest the feasibility to estimate ultrafast VC-MRI for on

  6. Flip-flop method: A new T1-weighted flow-MRI for plants studies.

    Science.gov (United States)

    Buy, Simon; Le Floch, Simon; Tang, Ning; Sidiboulenouar, Rahima; Zanca, Michel; Canadas, Patrick; Nativel, Eric; Cardoso, Maida; Alibert, Eric; Dupont, Guillaume; Ambard, Dominique; Maurel, Christophe; Verdeil, Jean-Luc; Bertin, Nadia; Goze-Bac, Christophe; Coillot, Christophe

    2018-01-01

    The climate warming implies an increase of stress of plants (drought and torrential rainfall). The understanding of plant behavior, in this context, takes a major importance and sap flow measurement in plants remains a key issue for plant understanding. Magnetic Resonance Imaging (MRI) which is well known to be a powerful tool to access water quantity can be used to measure moving water. We describe a novel flow-MRI method which takes advantage of inflow slice sensitivity. The method involves the slice selectivity in the context of multi slice spin echo sequence. Two sequences such as a given slice is consecutively inflow and outflow sensitive are performed, offering the possiblility to perform slow flow sensitive imaging in a quite straigthforward way. The method potential is demonstrated by imaging both a slow flow measurement on a test bench (as low as 10 μm.s-1) and the Poiseuille's profile of xylemian sap flow velocity in the xylematic tissues of a tomato plant stem.

  7. Utility of the 3D GRE method in the female pelvic area with 3T MRI

    International Nuclear Information System (INIS)

    Matsushita, Hiroki; Terada, Masaki; Oosugi, Masanori; Inoue, Kazuyasu; Anma, Takeshi

    2008-01-01

    A high signal-to-noise ratio (SNR) can be obtained in three-Tesla (3T) MRI, and it is possible to use it to shorten imaging time and improve spatial resolution. However, reports of its disadvantages have been increasing. We attempted to describe a high-resolution evaluation image that made the best use of a decrease in specific absorption rate (SAR) and high SNR by using the LAVA (liver acquisition with volume acceleration) method, a kind of three-dimensional GRE (3D gradient echo) method that did not show the above-mentioned disadvantage in obtaining a shadow inspection of the female pelvic area with 3T MRI. A 0.8 mm isovoxel image of excellent SNR could be obtained within about one and one-half minutes by using the LAVA method as a result of the examination. Moreover, a SAR that was problematic with the 3T MR device was able to be decreased, and was useful. (author)

  8. An accurate segmentation method for volumetry of brain tumor in 3D MRI

    Science.gov (United States)

    Wang, Jiahui; Li, Qiang; Hirai, Toshinori; Katsuragawa, Shigehiko; Li, Feng; Doi, Kunio

    2008-03-01

    Accurate volumetry of brain tumors in magnetic resonance imaging (MRI) is important for evaluating the interval changes in tumor volumes during and after treatment, and also for planning of radiation therapy. In this study, an automated volumetry method for brain tumors in MRI was developed by use of a new three-dimensional (3-D) image segmentation technique. First, the central location of a tumor was identified by a radiologist, and then a volume of interest (VOI) was determined automatically. To substantially simplify tumor segmentation, we transformed the 3-D image of the tumor into a two-dimensional (2-D) image by use of a "spiral-scanning" technique, in which a radial line originating from the center of the tumor scanned the 3-D image spirally from the "north pole" to the "south pole". The voxels scanned by the radial line provided a transformed 2-D image. We employed dynamic programming to delineate an "optimal" outline of the tumor in the transformed 2-D image. We then transformed the optimal outline back into 3-D image space to determine the volume of the tumor. The volumetry method was trained and evaluated by use of 16 cases with 35 brain tumors. The agreement between tumor volumes provided by computer and a radiologist was employed as a performance metric. Our method provided relatively accurate results with a mean agreement value of 88%.

  9. Comparative analysis of methods for extracting vessel network on breast MRI images

    Science.gov (United States)

    Gaizer, Bence T.; Vassiou, Katerina G.; Lavdas, Eleftherios; Arvanitis, Dimitrios L.; Fezoulidis, Ioannis V.; Glotsos, Dimitris T.

    2017-11-01

    Digital processing of MRI images aims to provide an automatized diagnostic evaluation of regular health screenings. Cancerous lesions are proven to cause an alteration in the vessel structure of the diseased organ. Currently there are several methods used for extraction of the vessel network in order to quantify its properties. In this work MRI images (Signa HDx 3.0T, GE Healthcare, courtesy of University Hospital of Larissa) of 30 female breasts were subjected to three different vessel extraction algorithms to determine the location of their vascular network. The first method is an experiment to build a graph over known points of the vessel network; the second algorithm aims to determine the direction and diameter of vessels at these points; the third approach is a seed growing algorithm, spreading selection to neighbors of the known vessel pixels. The possibilities shown by the different methods were analyzed, and quantitative measurements were performed. The data provided by these measurements showed no clear correlation with the presence or malignancy of tumors, based on the radiological diagnosis of skilled physicians.

  10. Brain tumor segmentation in MRI by using the fuzzy connectedness method

    Science.gov (United States)

    Liu, Jian-Guo; Udupa, Jayaram K.; Hackney, David; Moonis, Gul

    2001-07-01

    The aim of this paper is the precise and accurate quantification of brain tumor via MRI. This is very useful in evaluating disease progression, response to therapy, and the need for changes in treatment plans. We use multiple MRI protocols including FLAIR, T1, and T1 with Gd enhancement to gather information about different aspects of the tumor and its vicinity- edema, active regions, and scar left over due to surgical intervention. We have adapted the fuzzy connectedness framework to segment tumor and to measure its volume. The method requires only limited user interaction in routine clinical MRI. The first step in the process is to apply an intensity normalization method to the images so that the same body region has the same tissue meaning independent of the scanner and patient. Subsequently, a fuzzy connectedness algorithm is utilized to segment the different aspects of the tumor. The system has been tested, for its precision, accuracy, and efficiency, utilizing 40 patient studies. The percent coefficient of variation (% CV) in volume due to operator subjectivity in specifying seeds for fuzzy connectedness segmentation is less than 1%. The mean operator and computer time taken per study is 3 minutes. The package is designed to run under operator supervision. Delineation has been found to agree with the operators' visual inspection most of the time except in some cases when the tumor is close to the boundary of the brain. In the latter case, the scalp is included in the delineation and an operator has to exclude this manually. The methodology is rapid, robust, consistent, yielding highly reproducible measurements, and is likely to become part of the routine evaluation of brain tumor patients in our health system.

  11. New method for calculating the coupling coefficient in graded index optical fibers

    Science.gov (United States)

    Savović, Svetislav; Djordjevich, Alexandar

    2018-05-01

    A simple method is proposed for determining the mode coupling coefficient D in graded index multimode optical fibers. It only requires observation of the output modal power distribution P(m, z) for one fiber length z as the Gaussian launching modal power distribution changes, with the Gaussian input light distribution centered along the graded index optical fiber axis (θ0 = 0) without radial offset (r0 = 0). A similar method we previously proposed for calculating the coupling coefficient D in a step-index multimode optical fibers where the output angular power distributions P(θ, z) for one fiber length z with the Gaussian input light distribution launched centrally along the step-index optical fiber axis (θ0 = 0) is needed to be known.

  12. A Method for Manufacturing Oncological Phantoms for the Quantification of 18F-FDG PET and DW-MRI Studies

    Directory of Open Access Journals (Sweden)

    Francesca Gallivanone

    2017-01-01

    Full Text Available The aim of this work was to develop a method to manufacture oncological phantoms for quantitation purposes in 18F-FDG PET and DW-MRI studies. Radioactive and diffusion materials were prepared using a mixture of agarose and sucrose radioactive gels. T2 relaxation and diffusion properties of gels at different sucrose concentrations were evaluated. Realistic oncological lesions were created using 3D-printed plastic molds filled with the gel mixture. Once solidified, gels were extracted from molds and immersed in a low-radioactivity gel simulating normal background tissue. A breast cancer phantom was manufactured using the proposed method as an exploratory feasibility study, including several realistic oncological configurations in terms of both radioactivity and diffusion. The phantom was acquired in PET with 18F-FDG, immediately after solidification, and in DW-MRI the following day. Functional volumes characterizing the simulated BC lesions were segmented from PET and DW-MRI images. Measured radioactive uptake and ADC values were compared with gold standards. Phantom preparation was straightforward, and the time schedule was compatible with both PET and MRI measurements. Lesions appeared on 18F-FDG PET and DW-MRI images as expected, without visible artifacts. Lesion functional parameters revealed the phantom’s potential for validating quantification methods, in particular for new generation hybrid PET-MRI systems.

  13. Determination of the Local Thermal Conductivity of Functionally Graded Materials by a Laser Flash Method

    DEFF Research Database (Denmark)

    Zajas, Jan Jakub; Heiselberg, Per

    2013-01-01

    Determination of thermal conductivity of construction materials is essential to estimate their insulation capabilities. In most cases, homogenous materials are used and well developed methods exist for measurements of their thermal conductivity. The task becomes more challenging when dealing...... by scanning them point by point and determining the thermal conductivity as a function of the spatial dimensions. The method proves to be repeatable and of reasonable accuracy and can be used to determine the local thermal properties on a scale of millimeters. In this study, the method was successfully...... applied to create a map of thermal conductivity of a functionally graded material sample....

  14. A general method for selection of riboflavin-overproducing food grade micro-organisms

    OpenAIRE

    Burgess, Catherine M; Smid, Eddy J; Rutten, Ger; van Sinderen, Douwe

    2006-01-01

    Abstract Background This study describes a strategy to select and isolate spontaneous riboflavin-overproducing strains of Lactobacillus (Lb.) plantarum, Leuconostoc (Lc.) mesenteroides and Propionibacterium (P.) freudenreichii. Results The toxic riboflavin analogue roseoflavin was used to isolate natural riboflavin-overproducing variants of the food grade micro-organisms Lb. plantarum, Lc. mesenteroides and P. freudenreichii strains. The method was successfully employed for strains of all thr...

  15. MRI of the alar and transverse ligaments in whiplash-associated disorders (WAD) grades 1-2: high-signal changes by age, gender, event and time since trauma

    Energy Technology Data Exchange (ETDEWEB)

    Vetti, Nils; Kraakenes, Jostein; Roervik, Jarle; Espeland, Ansgar [Haukeland University Hospital, Department of Radiology, Bergen (Norway); University of Bergen, Section for Radiology, Department of Surgical Sciences, Bergen (Norway); Eide, Geir Egil [Haukeland University Hospital, Centre for Clinical Research, Bergen (Norway); University of Bergen, Department of Public Health and Primary Health Care, Bergen (Norway); Gilhus, Nils Erik [Haukeland University Hospital, Department of Neurology, Bergen (Norway); University of Bergen, Section for Neurology, Department of Clinical Medicine, Bergen (Norway)

    2009-04-15

    This study describes the prevalence of high-signal changes at magnetic resonance imaging (MRI) of the alar and transverse ligaments in whiplash-associated disorders (WAD) grades 1-2 in relation to age, gender, spinal degeneration, type of trauma event and time since trauma. In 1,266 consecutive WAD1-2 patients (779 women, 487 men; mean age 42 years) referred from clinicians, high-signal changes in the alar and transverse ligaments at high-resolution proton-weighted MRI were prospectively graded 0-3 based on a previously reported, reliable grading system. Type of event according to The International Statistical Classification of Diseases and Related Health Problems and time of trauma were obtained from referral letters. MRI showed grades 2-3 alar ligament changes in 449 (35.5%; 95% confidence interval (CI), 32.8 to 38.1%) and grades 2-3 transverse ligament changes in 311 (24.6%; 95% CI, 22.2% to 26.9%) of the 1,266 patients. Grades 2-3 changes were more common in men than women, odds ratio 1.9 (95% CI, 1.5 to 2.5) for alar and 1.5 (95% CI, 1.1 to 2.0) for transverse ligament changes. High-signal changes were not related to age, spinal degeneration, type of trauma event or time since trauma (median 5 years). Unilateral changes were more often left- than right-sided. High-signal changes of the alar and transverse ligaments are common in WAD1-2 and unlikely to represent age-dependent degeneration. Their male and left-side preponderance cannot be explained by variation in ligament stretching or image artefacts. Further studies are needed to clarify whether such changes are caused by trauma. (orig.)

  16. MRI of the alar and transverse ligaments in whiplash-associated disorders (WAD) grades 1-2: high-signal changes by age, gender, event and time since trauma

    International Nuclear Information System (INIS)

    Vetti, Nils; Kraakenes, Jostein; Roervik, Jarle; Espeland, Ansgar; Eide, Geir Egil; Gilhus, Nils Erik

    2009-01-01

    This study describes the prevalence of high-signal changes at magnetic resonance imaging (MRI) of the alar and transverse ligaments in whiplash-associated disorders (WAD) grades 1-2 in relation to age, gender, spinal degeneration, type of trauma event and time since trauma. In 1,266 consecutive WAD1-2 patients (779 women, 487 men; mean age 42 years) referred from clinicians, high-signal changes in the alar and transverse ligaments at high-resolution proton-weighted MRI were prospectively graded 0-3 based on a previously reported, reliable grading system. Type of event according to The International Statistical Classification of Diseases and Related Health Problems and time of trauma were obtained from referral letters. MRI showed grades 2-3 alar ligament changes in 449 (35.5%; 95% confidence interval (CI), 32.8 to 38.1%) and grades 2-3 transverse ligament changes in 311 (24.6%; 95% CI, 22.2% to 26.9%) of the 1,266 patients. Grades 2-3 changes were more common in men than women, odds ratio 1.9 (95% CI, 1.5 to 2.5) for alar and 1.5 (95% CI, 1.1 to 2.0) for transverse ligament changes. High-signal changes were not related to age, spinal degeneration, type of trauma event or time since trauma (median 5 years). Unilateral changes were more often left- than right-sided. High-signal changes of the alar and transverse ligaments are common in WAD1-2 and unlikely to represent age-dependent degeneration. Their male and left-side preponderance cannot be explained by variation in ligament stretching or image artefacts. Further studies are needed to clarify whether such changes are caused by trauma. (orig.)

  17. A novel method to assess pial collateralization from stroke perfusion MRI: subdividing Tmax into anatomical compartments

    International Nuclear Information System (INIS)

    Potreck, Arne; Seker, Fatih; Hoffmann, Angelika; Pfaff, Johannes; Bendszus, Martin; Heiland, Sabine; Pham, Mirko; Nagel, Simon

    2017-01-01

    To develop and validate a quantitative and observer-independent method to evaluate pial collateral circulation by DSC-perfusion MRI and test whether this novel method delivers diagnostic information which is redundant to or independent from conventional penumbra imaging by the mismatch approach. We retrospectively identified 47 patients with M1 occlusion who underwent MR diffusion/perfusion imaging and mechanical thrombectomy at our facility. By automated registration and segmentation, T max delays were attributed specifically to the pial, cortical and parenchymal compartments. The resulting pial volumes at delay were defined as the pial T max map-assessed collateral score (TMACS) and correlated with gold standard digital subtraction angiography (DSA). Mismatch ratio was assessed by conventional penumbra defining MRI criteria. Strong correlation was found between TMACS and angiographically assessed collateral score (Pearson ρ = -0.74, p < 0.001). In multiple logistic regression, both good collaterals according to TMACS [OR 4.3 (1.1-19, p = 0.04)] and mismatch ratio ≥ 3.5 [OR 12.3 (1.88-249, p = 0.03)] were independent predictors of favourable clinical outcome. Perfusion delay in the pial compartment, as evaluated by TMACS, closely reflects the extent of pial collaterals in gold-standard DSA. TMACS and mismatch ratio were found to be complementary predictors of a favourable clinical outcome, each adding independent predictive information. (orig.)

  18. Statistical clustering of parametric maps from dynamic contrast enhanced MRI and an associated decision tree model for non-invasive tumour grading of T1b solid clear cell renal cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Yin; Yuan, Qing; Zhang, Yue; Fulkerson, Michael [UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); Madhuranthakam, Ananth J. [UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); UT Southwestern Medical Center, Advanced Imaging Research Center, Dallas, TX (United States); Margulis, Vitaly; Cadeddu, Jeffrey A. [UT Southwestern Medical Center, Department of Urology, Dallas, TX (United States); UT Southwestern Medical Center, Kidney Cancer Program, Simmons Comprehensive Cancer Center, Dallas, TX (United States); Brugarolas, James [UT Southwestern Medical Center, Kidney Cancer Program, Simmons Comprehensive Cancer Center, Dallas, TX (United States); UT Southwestern Medical Center, Department of Internal Medicine, Dallas, TX (United States); Kapur, Payal [UT Southwestern Medical Center, Department of Urology, Dallas, TX (United States); UT Southwestern Medical Center, Kidney Cancer Program, Simmons Comprehensive Cancer Center, Dallas, TX (United States); UT Southwestern Medical Center, Department of Pathology, Dallas, Texas (United States); Pedrosa, Ivan [UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); UT Southwestern Medical Center, Advanced Imaging Research Center, Dallas, TX (United States); UT Southwestern Medical Center, Kidney Cancer Program, Simmons Comprehensive Cancer Center, Dallas, TX (United States)

    2018-01-15

    To apply a statistical clustering algorithm to combine information from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) into a single tumour map to distinguish high-grade from low-grade T1b clear cell renal cell carcinoma (ccRCC). This prospective, Institutional Review Board -approved, Health Insurance Portability and Accountability Act -compliant study included 18 patients with solid T1b ccRCC who underwent pre-surgical DCE MRI. After statistical clustering of the parametric maps of the transfer constant between the intravascular and extravascular space (K{sup trans}), rate constant (K{sub ep}) and initial area under the concentration curve (iAUC) with a fuzzy c-means (FCM) algorithm, each tumour was segmented into three regions (low/medium/high active areas). Percentages of each region and tumour size were compared to tumour grade at histopathology. A decision-tree model was constructed to select the best parameter(s) to predict high-grade ccRCC. Seven high-grade and 11 low-grade T1b ccRCCs were included. High-grade histology was associated with higher percent high active areas (p = 0.0154) and this was the only feature selected by the decision tree model, which had a diagnostic performance of 78% accuracy, 86% sensitivity, 73% specificity, 67% positive predictive value and 89% negative predictive value. The FCM integrates multiple DCE-derived parameter maps and identifies tumour regions with unique pharmacokinetic characteristics. Using this approach, a decision tree model using criteria beyond size to predict tumour grade in T1b ccRCCs is proposed. (orig.)

  19. Statistical clustering of parametric maps from dynamic contrast enhanced MRI and an associated decision tree model for non-invasive tumour grading of T1b solid clear cell renal cell carcinoma

    International Nuclear Information System (INIS)

    Xi, Yin; Yuan, Qing; Zhang, Yue; Fulkerson, Michael; Madhuranthakam, Ananth J.; Margulis, Vitaly; Cadeddu, Jeffrey A.; Brugarolas, James; Kapur, Payal; Pedrosa, Ivan

    2018-01-01

    To apply a statistical clustering algorithm to combine information from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) into a single tumour map to distinguish high-grade from low-grade T1b clear cell renal cell carcinoma (ccRCC). This prospective, Institutional Review Board -approved, Health Insurance Portability and Accountability Act -compliant study included 18 patients with solid T1b ccRCC who underwent pre-surgical DCE MRI. After statistical clustering of the parametric maps of the transfer constant between the intravascular and extravascular space (K trans ), rate constant (K ep ) and initial area under the concentration curve (iAUC) with a fuzzy c-means (FCM) algorithm, each tumour was segmented into three regions (low/medium/high active areas). Percentages of each region and tumour size were compared to tumour grade at histopathology. A decision-tree model was constructed to select the best parameter(s) to predict high-grade ccRCC. Seven high-grade and 11 low-grade T1b ccRCCs were included. High-grade histology was associated with higher percent high active areas (p = 0.0154) and this was the only feature selected by the decision tree model, which had a diagnostic performance of 78% accuracy, 86% sensitivity, 73% specificity, 67% positive predictive value and 89% negative predictive value. The FCM integrates multiple DCE-derived parameter maps and identifies tumour regions with unique pharmacokinetic characteristics. Using this approach, a decision tree model using criteria beyond size to predict tumour grade in T1b ccRCCs is proposed. (orig.)

  20. Assessing metacognition of grade 2 and grade 4 students using an adaptation of multi-method interview approach during mathematics problem-solving

    Science.gov (United States)

    Kuzle, A.

    2018-06-01

    The important role that metacognition plays as a predictor for student mathematical learning and for mathematical problem-solving, has been extensively documented. But only recently has attention turned to primary grades, and more research is needed at this level. The goals of this paper are threefold: (1) to present metacognitive framework during mathematics problem-solving, (2) to describe their multi-method interview approach developed to study student mathematical metacognition, and (3) to empirically evaluate the utility of their model and the adaptation of their approach in the context of grade 2 and grade 4 mathematics problem-solving. The results are discussed not only with regard to further development of the adapted multi-method interview approach, but also with regard to their theoretical and practical implications.

  1. Comparison of 18F-FET PET and perfusion-weighted MRI for glioma grading. A hybrid PET/MR study

    International Nuclear Information System (INIS)

    Verger, Antoine; Filss, Christian P.; Lohmann, Philipp; Stoffels, Gabriele; Rota Kops, Elena; Sabel, Michael; Wittsack, Hans J.; Galldiks, Norbert; Fink, Gereon R.; Shah, Nadim J.; Langen, Karl-Josef

    2017-01-01

    Both perfusion-weighted MR imaging (PWI) and O-(2- 18 F-fluoroethyl)-L-tyrosine PET ( 18 F-FET) provide grading information in cerebral gliomas. The aim of this study was to compare the diagnostic value of 18 F-FET PET and PWI for tumor grading in a series of patients with newly diagnosed, untreated gliomas using an integrated PET/MR scanner. Seventy-two patients with untreated gliomas [22 low-grade gliomas (LGG), and 50 high-grade gliomas (HGG)] were investigated with 18 F-FET PET and PWI using a hybrid PET/MR scanner. After visual inspection of PET and PWI maps (rCBV, rCBF, MTT), volumes of interest (VOIs) with a diameter of 16 mm were centered upon the maximum of abnormality in the tumor area in each modality and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios (TBR mean , TBR max ) were calculated. In addition, Time-to-Peak (TTP) and slopes of time-activity curves were calculated for 18 F-FET PET. Diagnostic accuracies of 18 F-FET PET and PWI for differentiating low-grade glioma (LGG) from high-grade glioma (HGG) were evaluated by receiver operating characteristic analyses (area under the curve; AUC). The diagnostic accuracy of 18 F-FET PET and PWI to discriminate LGG from HGG was similar with highest AUC values for TBR mean and TBR max of 18 F-FET PET uptake (0.80, 0.83) and for TBR mean and TBR max of rCBV (0.80, 0.81). In case of increased signal in the tumor area with both methods (n = 32), local hot-spots were incongruent in 25 patients (78%) with a mean distance of 10.6 ± 9.5 mm. Dynamic FET PET and combination of different parameters did not further improve diagnostic accuracy. Both 18 F-FET PET and PWI discriminate LGG from HGG with similar diagnostic performance. Regional abnormalities in the tumor area are usually not congruent indicating that tumor grading by 18 F-FET PET and PWI is based on different pathophysiological phenomena. (orig.)

  2. Comparison of {sup 18}F-FET PET and perfusion-weighted MRI for glioma grading. A hybrid PET/MR study

    Energy Technology Data Exchange (ETDEWEB)

    Verger, Antoine [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); Lorraine University, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Nancy (France); Lorraine University, IADI, INSERM, UMR 947, Nancy (France); Filss, Christian P. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Lohmann, Philipp; Stoffels, Gabriele; Rota Kops, Elena [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); Sabel, Michael [University of Duesseldorf, Department of Neurosurgery, Duesseldorf (Germany); Wittsack, Hans J. [University Duesseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Galldiks, Norbert; Fink, Gereon R. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); University of Cologne, Department of Neurology, Cologne (Germany); University of Cologne and Bonn, Center of Integrated Oncology (CIO), Bonn (Germany); Shah, Nadim J. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Neurology, Aachen (Germany); Juelich-Aachen Research Alliance (JARA), Section JARA-Brain, Juelich (Germany); Langen, Karl-Josef [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Juelich-Aachen Research Alliance (JARA), Section JARA-Brain, Juelich (Germany)

    2017-12-15

    Both perfusion-weighted MR imaging (PWI) and O-(2-{sup 18}F-fluoroethyl)-L-tyrosine PET ({sup 18}F-FET) provide grading information in cerebral gliomas. The aim of this study was to compare the diagnostic value of {sup 18}F-FET PET and PWI for tumor grading in a series of patients with newly diagnosed, untreated gliomas using an integrated PET/MR scanner. Seventy-two patients with untreated gliomas [22 low-grade gliomas (LGG), and 50 high-grade gliomas (HGG)] were investigated with {sup 18}F-FET PET and PWI using a hybrid PET/MR scanner. After visual inspection of PET and PWI maps (rCBV, rCBF, MTT), volumes of interest (VOIs) with a diameter of 16 mm were centered upon the maximum of abnormality in the tumor area in each modality and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios (TBR{sub mean}, TBR{sub max}) were calculated. In addition, Time-to-Peak (TTP) and slopes of time-activity curves were calculated for {sup 18}F-FET PET. Diagnostic accuracies of {sup 18}F-FET PET and PWI for differentiating low-grade glioma (LGG) from high-grade glioma (HGG) were evaluated by receiver operating characteristic analyses (area under the curve; AUC). The diagnostic accuracy of {sup 18}F-FET PET and PWI to discriminate LGG from HGG was similar with highest AUC values for TBR{sub mean} and TBR{sub max} of {sup 18}F-FET PET uptake (0.80, 0.83) and for TBR{sub mean} and TBR{sub max} of rCBV (0.80, 0.81). In case of increased signal in the tumor area with both methods (n = 32), local hot-spots were incongruent in 25 patients (78%) with a mean distance of 10.6 ± 9.5 mm. Dynamic FET PET and combination of different parameters did not further improve diagnostic accuracy. Both {sup 18}F-FET PET and PWI discriminate LGG from HGG with similar diagnostic performance. Regional abnormalities in the tumor area are usually not congruent indicating that tumor grading by {sup 18}F-FET PET and PWI is based on different pathophysiological phenomena. (orig.)

  3. A novel integrative method for analyzing eye and hand behaviour during reaching and grasping in an MRI environment.

    Science.gov (United States)

    Lawrence, Jane M; Abhari, Kamyar; Prime, Steven L; Meek, Benjamin P; Desanghere, Loni; Baugh, Lee A; Marotta, Jonathan J

    2011-06-01

    The development of noninvasive neuroimaging techniques, such as fMRI, has rapidly advanced our understanding of the neural systems underlying the integration of visual and motor information. However, the fMRI experimental design is restricted by several environmental elements, such as the presence of the magnetic field and the restricted view of the participant, making it difficult to monitor and measure behaviour. The present article describes a novel, specialized software package developed in our laboratory called Biometric Integration Recording and Analysis (BIRA). BIRA integrates video with kinematic data derived from the hand and eye, acquired using MRI-compatible equipment. The present article demonstrates the acquisition and analysis of eye and hand data using BIRA in a mock (0 Tesla) scanner. A method for collecting and integrating gaze and kinematic data in fMRI studies on visuomotor behaviour has several advantages: Specifically, it will allow for more sophisticated, behaviourally driven analyses and eliminate potential confounds of gaze or kinematic data.

  4. MRI definition of target volumes using fuzzy logic method for three-dimensional conformal radiation therapy

    International Nuclear Information System (INIS)

    Caudrelier, Jean-Michel; Vial, Stephane; Gibon, David; Kulik, Carine; Fournier, Charles; Castelain, Bernard; Coche-Dequeant, Bernard; Rousseau, Jean

    2003-01-01

    Purpose: Three-dimensional (3D) volume determination is one of the most important problems in conformal radiation therapy. Techniques of volume determination from tomographic medical imaging are usually based on two-dimensional (2D) contour definition with the result dependent on the segmentation method used, as well as on the user's manual procedure. The goal of this work is to describe and evaluate a new method that reduces the inaccuracies generally observed in the 2D contour definition and 3D volume reconstruction process. Methods and Materials: This new method has been developed by integrating the fuzziness in the 3D volume definition. It first defines semiautomatically a minimal 2D contour on each slice that definitely contains the volume and a maximal 2D contour that definitely does not contain the volume. The fuzziness region in between is processed using possibility functions in possibility theory. A volume of voxels, including the membership degree to the target volume, is then created on each slice axis, taking into account the slice position and slice profile. A resulting fuzzy volume is obtained after data fusion between multiorientation slices. Different studies have been designed to evaluate and compare this new method of target volume reconstruction and a classical reconstruction method. First, target definition accuracy and robustness were studied on phantom targets. Second, intra- and interobserver variations were studied on radiosurgery clinical cases. Results: The absolute volume errors are less than or equal to 1.5% for phantom volumes calculated by the fuzzy logic method, whereas the values obtained with the classical method are much larger than the actual volumes (absolute volume errors up to 72%). With increasing MRI slice thickness (1 mm to 8 mm), the phantom volumes calculated by the classical method are increasing exponentially with a maximum absolute error up to 300%. In contrast, the absolute volume errors are less than 12% for phantom

  5. Direct Patlak Reconstruction From Dynamic PET Data Using the Kernel Method With MRI Information Based on Structural Similarity.

    Science.gov (United States)

    Gong, Kuang; Cheng-Liao, Jinxiu; Wang, Guobao; Chen, Kevin T; Catana, Ciprian; Qi, Jinyi

    2018-04-01

    Positron emission tomography (PET) is a functional imaging modality widely used in oncology, cardiology, and neuroscience. It is highly sensitive, but suffers from relatively poor spatial resolution, as compared with anatomical imaging modalities, such as magnetic resonance imaging (MRI). With the recent development of combined PET/MR systems, we can improve the PET image quality by incorporating MR information into image reconstruction. Previously, kernel learning has been successfully embedded into static and dynamic PET image reconstruction using either PET temporal or MRI information. Here, we combine both PET temporal and MRI information adaptively to improve the quality of direct Patlak reconstruction. We examined different approaches to combine the PET and MRI information in kernel learning to address the issue of potential mismatches between MRI and PET signals. Computer simulations and hybrid real-patient data acquired on a simultaneous PET/MR scanner were used to evaluate the proposed methods. Results show that the method that combines PET temporal information and MRI spatial information adaptively based on the structure similarity index has the best performance in terms of noise reduction and resolution improvement.

  6. A new integrated dual time-point amyloid PET/MRI data analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Cecchin, Diego; Zucchetta, Pietro; Turco, Paolo; Bui, Franco [University Hospital of Padua, Nuclear Medicine Unit, Department of Medicine - DIMED, Padua (Italy); Barthel, Henryk; Tiepolt, Solveig; Sabri, Osama [Leipzig University, Department of Nuclear Medicine, Leipzig (Germany); Poggiali, Davide; Cagnin, Annachiara; Gallo, Paolo [University Hospital of Padua, Neurology, Department of Neurosciences (DNS), Padua (Italy); Frigo, Anna Chiara [University Hospital of Padua, Biostatistics, Epidemiology and Public Health Unit, Department of Cardiac, Thoracic and Vascular Sciences, Padua (Italy)

    2017-11-15

    In the initial evaluation of patients with suspected dementia and Alzheimer's disease, there is no consensus on how to perform semiquantification of amyloid in such a way that it: (1) facilitates visual qualitative interpretation, (2) takes the kinetic behaviour of the tracer into consideration particularly with regard to at least partially correcting for blood flow dependence, (3) analyses the amyloid load based on accurate parcellation of cortical and subcortical areas, (4) includes partial volume effect correction (PVEC), (5) includes MRI-derived topographical indexes, (6) enables application to PET/MRI images and PET/CT images with separately acquired MR images, and (7) allows automation. A method with all of these characteristics was retrospectively tested in 86 subjects who underwent amyloid ({sup 18}F-florbetaben) PET/MRI in a clinical setting (using images acquired 90-110 min after injection, 53 were classified visually as amyloid-negative and 33 as amyloid-positive). Early images after tracer administration were acquired between 0 and 10 min after injection, and later images were acquired between 90 and 110 min after injection. PVEC of the PET data was carried out using the geometric transfer matrix method. Parametric images and some regional output parameters, including two innovative ''dual time-point'' indexes, were obtained. Subjects classified visually as amyloid-positive showed a sparse tracer uptake in the primary sensory, motor and visual areas in accordance with the isocortical stage of the topographic distribution of the amyloid plaque (Braak stages V/VI). In patients classified visually as amyloid-negative, the method revealed detectable levels of tracer uptake in the basal portions of the frontal and temporal lobes, areas that are known to be sites of early deposition of amyloid plaques that probably represented early accumulation (Braak stage A) that is typical of normal ageing. There was a strong correlation between

  7. A new integrated dual time-point amyloid PET/MRI data analysis method

    International Nuclear Information System (INIS)

    Cecchin, Diego; Zucchetta, Pietro; Turco, Paolo; Bui, Franco; Barthel, Henryk; Tiepolt, Solveig; Sabri, Osama; Poggiali, Davide; Cagnin, Annachiara; Gallo, Paolo; Frigo, Anna Chiara

    2017-01-01

    In the initial evaluation of patients with suspected dementia and Alzheimer's disease, there is no consensus on how to perform semiquantification of amyloid in such a way that it: (1) facilitates visual qualitative interpretation, (2) takes the kinetic behaviour of the tracer into consideration particularly with regard to at least partially correcting for blood flow dependence, (3) analyses the amyloid load based on accurate parcellation of cortical and subcortical areas, (4) includes partial volume effect correction (PVEC), (5) includes MRI-derived topographical indexes, (6) enables application to PET/MRI images and PET/CT images with separately acquired MR images, and (7) allows automation. A method with all of these characteristics was retrospectively tested in 86 subjects who underwent amyloid ( 18 F-florbetaben) PET/MRI in a clinical setting (using images acquired 90-110 min after injection, 53 were classified visually as amyloid-negative and 33 as amyloid-positive). Early images after tracer administration were acquired between 0 and 10 min after injection, and later images were acquired between 90 and 110 min after injection. PVEC of the PET data was carried out using the geometric transfer matrix method. Parametric images and some regional output parameters, including two innovative ''dual time-point'' indexes, were obtained. Subjects classified visually as amyloid-positive showed a sparse tracer uptake in the primary sensory, motor and visual areas in accordance with the isocortical stage of the topographic distribution of the amyloid plaque (Braak stages V/VI). In patients classified visually as amyloid-negative, the method revealed detectable levels of tracer uptake in the basal portions of the frontal and temporal lobes, areas that are known to be sites of early deposition of amyloid plaques that probably represented early accumulation (Braak stage A) that is typical of normal ageing. There was a strong correlation between age

  8. Synthesis of nano grade hollow silica sphere via a soft template method.

    Science.gov (United States)

    Tsai, Ming-Shyong; Li, Miao Ju; Yen, Fu-Hsu

    2008-06-01

    The nano grade hollow silica sphere (HSS) was synthesized by a novel soft template method. We found that the precipitate of aluminate had a porous structure that could be the soft template for HSS. After mixing the colloidal silica with the aluminate precipitate, the bubble trapped in this porous structure could form the nano grade HSS. The aluminate precipitate was removed by adjusting the pH of the slurry to approximately 1. The outside diameter, the specific surface, and the mean pore size diameter of the forming HSS were 60-90 nm, 571 m2/g, and 3 nm, respectively. The formed HSS was collected by modifying the surface with Si(OCH3)3CHCH2 (VTMO) and then filtrating the precipitated gel in the n-butanol and ethanol solvent system.

  9. Elastic Stress Analysis of Rotating Functionally Graded Annular Disk of Variable Thickness Using Finite Difference Method

    Directory of Open Access Journals (Sweden)

    Mohammad Hadi Jalali

    2018-01-01

    Full Text Available Elastic stress analysis of rotating variable thickness annular disk made of functionally graded material (FGM is presented. Elasticity modulus, density, and thickness of the disk are assumed to vary radially according to a power-law function. Radial stress, circumferential stress, and radial deformation of the rotating FG annular disk of variable thickness with clamped-clamped (C-C, clamped-free (C-F, and free-free (F-F boundary conditions are obtained using the numerical finite difference method, and the effects of the graded index, thickness variation, and rotating speed on the stresses and deformation are evaluated. It is shown that using FG material could decrease the value of radial stress and increase the radial displacement in a rotating thin disk. It is also demonstrated that increasing the rotating speed can strongly increase the stress in the FG annular disk.

  10. Preparation of Al/Si functionally graded materials using ultrasonic separation method

    Directory of Open Access Journals (Sweden)

    Zhang Zhongtao

    2008-08-01

    Full Text Available Functionally graded materials (FGM have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare Al/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a large quantity of primary Si gradually to the eutectic, and fi nally to the hypoeutectic with numerous primary Al dendrites. The distribution of primary Si and microhardness of the FGM sample also presented graded characteristics, resulting that the wear resistance of the FGM sample decreased from top to bottom. Preliminary discussion was made on the mechanism of the formation of Al/Si FGM.

  11. Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

    International Nuclear Information System (INIS)

    1990-01-01

    This international Standard specifies a precise and accurate gravimetric method for determining the uranium content in uranyl nitrate product solutions of nuclear grade quality at concentrations above 100 g/l of uranium. Non-volatile impurities influence the accuracy of the method. Uranyl nitrate is converted into uranium octoxide (U 3 O 8 ) by ignition in air to constant mass at 900 deg. C ± 10 deg. C. Calculation of the uranium content in the sample using a gravimetric conversion factor which depends on the isotopic composition of the uranium. The isotopic composition is determined by mass spectrometry

  12. Study on creep behavior of Grade 91 heat-resistant steel using theta projection method

    Science.gov (United States)

    Ren, Facai; Tang, Xiaoying

    2017-10-01

    Creep behavior of Grade 91 heat-resistant steel used for steam cooler was characterized using the theta projection method. Creep tests were conducted at the temperature of 923K under the stress ranging from 100-150MPa. Based on the creep curve results, four theta parameters were established using a nonlinear least square fitting method. Four theta parameters showed a good linearity as a function of stress. The predicted curves coincided well with the experimental data and creep curves were also modeled to the low stress level of 60MPa.

  13. Research for correction pre-operative MRI images of brain during operation using particle method simulation

    International Nuclear Information System (INIS)

    Shino, Ryosaku; Koshizuka, Seiichi; Sakai, Mikio; Ito, Hirotaka; Iseki, Hiroshi; Muragaki, Yoshihiro

    2010-01-01

    In the neurosurgical procedures, surgeon formulates a surgery plan based on pre-operative images such as MRI. However, the brain is transformed by removal of the affected area. In this paper, we propose a method for reconstructing pre-operative images involving the deformation with physical simulation. First, the domain of brain is identified in pre-operative images. Second, we create particles for physical simulation. Then, we carry out the linear elastic simulation taking into account the gravity. Finally, we reconstruct pre-operative images with deformation according to movement of the particles. We show the effectiveness of this method by reconstructing the pre-operative image actually taken before surgery. (author)

  14. A method for independent component graph analysis of resting-state fMRI

    DEFF Research Database (Denmark)

    de Paula, Demetrius Ribeiro; Ziegler, Erik; Abeyasinghe, Pubuditha M.

    2017-01-01

    Introduction Independent component analysis (ICA) has been extensively used for reducing task-free BOLD fMRI recordings into spatial maps and their associated time-courses. The spatially identified independent components can be considered as intrinsic connectivity networks (ICNs) of non-contiguou......Introduction Independent component analysis (ICA) has been extensively used for reducing task-free BOLD fMRI recordings into spatial maps and their associated time-courses. The spatially identified independent components can be considered as intrinsic connectivity networks (ICNs) of non......-contiguous regions. To date, the spatial patterns of the networks have been analyzed with techniques developed for volumetric data. Objective Here, we detail a graph building technique that allows these ICNs to be analyzed with graph theory. Methods First, ICA was performed at the single-subject level in 15 healthy...... parcellated regions. Third, between-node functional connectivity was established by building edge weights for each networks. Group-level graph analysis was finally performed for each network and compared to the classical network. Results Network graph comparison between the classically constructed network...

  15. Coupled DQ-FE methods for two dimensional transient heat transfer analysis of functionally graded material

    Energy Technology Data Exchange (ETDEWEB)

    Golbahar Haghighi, M.R.; Eghtesad, M. [Department of Mechanical Engineering, School of Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Malekzadeh, P. [Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Boushehr 75169-13798 (Iran, Islamic Republic of)], E-mail: malekzadeh@pgu.ac.ir

    2008-05-15

    In this paper, a mixed finite element (FE) and differential quadrature (DQ) method as a simple, accurate and computationally efficient numerical tool for two dimensional transient heat transfer analysis of functionally graded materials (FGMs) is developed. The method benefits from the high accuracy, fast convergence behavior and low computational efforts of the DQ in conjunction with the advantages of the FE method in general geometry, loading and systematic boundary treatment. Also, the boundary conditions at the top and bottom surfaces of the domain can be implemented more precisely and in strong form. The temporal derivatives are discretized using an incremental DQ method (IDQM), whose numerical stability is not sensitive to time step size. The effects of non-uniform convective-radiative conditions on the boundaries are investigated. The accuracy of the proposed method is demonstrated by comparing its results with those available in the literature. It is shown that using few grid points, highly accurate results can be obtained.

  16. Mixed-Method Research on Learning Vocabulary through Technology Reveals Vocabulary Growth in Second-Grade Students

    Science.gov (United States)

    Huang, SuHua

    2015-01-01

    A mixed-method embedded research design was employed to investigate the effectiveness of the integration of technology for second-grade students' vocabulary development and learning. Two second-grade classes with a total of 40 students (21 boys and 19 girls) were randomly selected to participate in this study for the course of a semester. One…

  17. FY1995 report on the novel methods for magnetic resonance imaging; 1995 nendo senshin MRI gazoka shuho no kiso kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The purpose of this project is to develop new 2-dimensional ultrafast MRI (Magnetic Resonance Imaging) methods for the Image Guided Cancer Therapy (IGT) and the non-invasive clinical diagnosis. We have developed two MRI methods. They can reconstruct a two dimensional image by only a RF excitation and slow changing of gradient fields. This paper describes theoretically how to apply the RF wave and the gradient in x, y and z direction, respectively. Echo signals are acquired under multi-frequency resonance. The frequency bandwidth of the RF wave adjusts the field of view (FOV) of the imaging plane. Biological effects of the applied RF wave was evaluated by the brain microdialysis. In animal experiments, these was not significant change of neurotransmitters subject to the RF wave. From these theoretical and experimental results, these MRI methods are applicable to IGT and the clinical diagnosis for the cancer and other diseases. (NEDO)

  18. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning

    International Nuclear Information System (INIS)

    Farace, Paolo; Antolini, Renzo; Pontalti, Rolando; Cristoforetti, Luca; Scarpa, Marina

    1997-01-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning. (author)

  19. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Farace, Paolo; Antolini, Renzo [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy); Pontalti, Rolando; Cristoforetti, Luca [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Scarpa, Marina [Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy)

    1997-11-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning. (author)

  20. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning.

    Science.gov (United States)

    Farace, P; Pontalti, R; Cristoforetti, L; Antolini, R; Scarpa, M

    1997-11-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning.

  1. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Farace, Paolo; Antolini, Renzo [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy); Pontalti, Rolando; Cristoforetti, Luca [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Scarpa, Marina [Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy)

    1997-11-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning. (author)

  2. Heart MRI

    Science.gov (United States)

    Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

  3. Grading of mitral regurgitation in mitral valve prolapse using the average pixel intensity method.

    Science.gov (United States)

    Kamoen, Victor; El Haddad, Milad; De Buyzere, Marc; De Backer, Tine; Timmermans, Frank

    2018-05-01

    We recently reported the feasibility of the average pixel intensity (API) method for grading mitral regurgitation (MR) in a heterogeneous MR population. Since mitral valve prolapse (MVP) is an important cause of primary MR, we more specifically investigated the feasibility of the API method and the MR flow dynamics in patients with MVP. Transthoracic echocardiography was performed by a single operator in consecutive MVP patients (n=112). MR was assessed using the API method, color Doppler, vena contracta width (VCW), effective regurgitant orifice area (PISA-EROA) and regurgitant volume (PISA-RV). The API method was feasible in 89% of all MVP patients (68%, 71% for VCW and PISA method, respectively ;pMVP with non-holosystolic MR were 0.989 and 0.995. For the overall MVP-MR population, API had significant correlations with direct and indirect measures of MR severity. Based on ROC curves, an API cutoff value of 125 au was suggested to identify severe MR in MVP and a MR duration/systolic time ratioMVP-MR) identifies patients with non-severe MR (APIMVP had severe MR (API>125). Finally, API analysis of the proto-, mid- and telesystolic phases of MR in MVP showed different kinetics in non-holosystolic compared to holosystolic MVP. The API method is a feasible and reproducible method for grading MVP-MR. As the API method takes into account the temporal MR flow changes during the entire systolic cycle, it may be of added value in clinical practice. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Modification of backgammon shape cathode and graded charge division readout method for a novel triple charge division centroid finding method

    International Nuclear Information System (INIS)

    Javanmardi, F.; Matoba, M.; Sakae, T.

    1996-01-01

    Triple Charge Division (TCD) centroid finding method that uses modified pattern of Backgammon Shape Cathode (MBSC) is introduced for medium range length position sensitive detectors with optimum numbers of cathode segments. MBSC pattern has three separated areas and uses saw tooth like insulator gaps for separating the areas. Side areas of the MBSC pattern are severed by a central common area. Size of the central area is twice of the size of both sides. Whereas central area is the widest area among three, both sides' areas have the main role in position sensing. With the same resolution and linearity, active region of original Backgammon pattern increases twice by using MBSC pattern, and with the same length, linearity of TCD centroid finding is much better than Backgammon charge division readout method. Linearity prediction of TCD centroid finding and experimental results conducted us to find an optimum truncation of the apices of MBCS pattern in the central area. The TCD centroid finding has an especial readout method since charges must be collected from two segments in both sides and from three segments in the central area of MBSC pattern. The so called Graded Charge Division (GCD) is the especial readout method for TCD. The GCD readout is a combination of the charge division readout and sequence grading of serial segments. Position sensing with TCD centroid finding and GCD readout were done by two sizes MBSC patterns (200mm and 80mm) and Spatial resolution about 1% of the detector length is achieved

  5. A fuzzy inventory model with acceptable shortage using graded mean integration value method

    Science.gov (United States)

    Saranya, R.; Varadarajan, R.

    2018-04-01

    In many inventory models uncertainty is due to fuzziness and fuzziness is the closed possible approach to reality. In this paper, we proposed a fuzzy inventory model with acceptable shortage which is completely backlogged. We fuzzily the carrying cost, backorder cost and ordering cost using Triangular and Trapezoidal fuzzy numbers to obtain the fuzzy total cost. The purpose of our study is to defuzzify the total profit function by Graded Mean Integration Value Method. Further a numerical example is also given to demonstrate the developed crisp and fuzzy models.

  6. Development of a non-destructive method to identify different grades of stainless steel

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman

    2003-01-01

    One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive X-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyse a very wide concentration range, fast analysis with no sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels. Comparison of the results for certified reference standards obtained from this analysis and that of its certified value shows very small differences between them. (Author)

  7. Development of a non-destructive method to identify different grades of stainless steel

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman

    2004-01-01

    One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive x-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyze a very wide concentration range, fast analysis with no tedious sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels. Comparison of the results obtained from this analysis with certified reference standards show very small differences between them. (Author)

  8. Estimation of intermediate-grade uranium resources II. Proposed method for estimating intermediate-grade uranium resources in roll-front deposits. Final report

    International Nuclear Information System (INIS)

    Lambie, F.W.; Yee, S.N.

    1981-09-01

    The purpose of this and a previous project was to examine the feasibility of estimating intermediate grade uranium (0.01 to 0.05% U 3 O 8 ) on the basis of existing, sparsely drilled holes. All data are from the Powder River Basin in Wyoming. DOE makes preliminary estimates of endowment by calculating an Average Area of Influence (AAI) based on densely drilled areas, multiplying that by the thickness of the mineralization and then dividing by a tonnage factor. The resulting tonnage of ore is then multiplied by the average grade of the interval to obtain the estimate of U 3 O 8 tonnage. Total endowment is the sum of these values over all mineralized intervals in all wells in the area. In regions where wells are densely drilled and approximately regularly spaced this technique approaches the classical polygonal estimation technique used to estimate ore reserves and should be fairly reliable. The method is conservative because: (1) in sparsely drilled regions a large fraction of the area is not considered to contribute to endowment; (2) there is a bias created by the different distributions of point grades and mining block grades. A conservative approach may be justified for purposes of ore reserve estimation, where large investments may hinge on local forecasts. But for estimates of endowment over areas as large as 1 0 by 2 0 quadrangles, or the nation as a whole, errors in local predictions are not critical as long as they tend to cancel and a less conservative estimation approach may be justified.One candidate, developed for this study and described is called the contoured thickness technique. A comparison of estimates based on the contoured thickness approach with DOE calculations for five areas of Wyoming roll-fronts in the Powder River Basin is presented. The sensitivity of the technique to well density is examined and the question of predicting intermediate grade endowment from data on higher grades is discussed

  9. A tale of two methods: combining near-infrared spectroscopy with MRI for studies of brain oxygenation and metabolism.

    Science.gov (United States)

    Dunn, Jeff F; Nathoo, Nabeela; Yang, Runze

    2014-01-01

    Combining magnetic resonance imaging (MRI) with near-infrared spectroscopy (NIRS) leads to excellent synergies which can improve the interpretation of either method and can provide novel data with respect to measuring brain oxygenation and metabolism. MRI has good spatial resolution, can detect a range of physiological parameters and is sensitive to changes in deoxyhemoglobin content. NIRS has lower spatial resolution, but can detect, and with specific technologies, quantify, deoxyhemoglobin, oxyhemoglobin, total hemoglobin and cytochrome oxidase. This paper reviews the application of both methods, as a multimodal technology, for assessing changes in brain oxygenation that may occur with changes in functional activation state or metabolic rate. Examples of hypoxia and ischemia are shown. Data support the concept of reduced metabolic rate resulting from hypoxia/ischemia and that metabolic rate in brain is not close to oxygen limitation during normoxia. We show that multimodal MRI and NIRS can provide novel information for studies of brain metabolism.

  10. MRI of the Chest

    Medline Plus

    Full Text Available ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ... might be obscured by bone with other imaging methods. The contrast material used in MRI exams is ...

  11. Optimizing methods for linking cinematic features to fMRI data.

    Science.gov (United States)

    Kauttonen, Janne; Hlushchuk, Yevhen; Tikka, Pia

    2015-04-15

    One of the challenges of naturalistic neurosciences using movie-viewing experiments is how to interpret observed brain activations in relation to the multiplicity of time-locked stimulus features. As previous studies have shown less inter-subject synchronization across viewers of random video footage than story-driven films, new methods need to be developed for analysis of less story-driven contents. To optimize the linkage between our fMRI data collected during viewing of a deliberately non-narrative silent film 'At Land' by Maya Deren (1944) and its annotated content, we combined the method of elastic-net regularization with the model-driven linear regression and the well-established data-driven independent component analysis (ICA) and inter-subject correlation (ISC) methods. In the linear regression analysis, both IC and region-of-interest (ROI) time-series were fitted with time-series of a total of 36 binary-valued and one real-valued tactile annotation of film features. The elastic-net regularization and cross-validation were applied in the ordinary least-squares linear regression in order to avoid over-fitting due to the multicollinearity of regressors, the results were compared against both the partial least-squares (PLS) regression and the un-regularized full-model regression. Non-parametric permutation testing scheme was applied to evaluate the statistical significance of regression. We found statistically significant correlation between the annotation model and 9 ICs out of 40 ICs. Regression analysis was also repeated for a large set of cubic ROIs covering the grey matter. Both IC- and ROI-based regression analyses revealed activations in parietal and occipital regions, with additional smaller clusters in the frontal lobe. Furthermore, we found elastic-net based regression more sensitive than PLS and un-regularized regression since it detected a larger number of significant ICs and ROIs. Along with the ISC ranking methods, our regression analysis proved

  12. MRI in acute phase of whiplash injury

    Energy Technology Data Exchange (ETDEWEB)

    Fagerlund, M. [Dept. of Diagnostic Radiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Bjoernebrink, J. [Dept. of Diagnostic Radiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Pettersson, K. [Dept. of Orthopaedic Surgery, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Hildingsson, C. [Dept. of Orthopaedic Surgery, Univ. Hospital of Northern Sweden, Umeaa (Sweden)

    1995-11-01

    A prospective MRI study of 39 whiplash patients was performed and the results were compared with the clinical findings within 15 days after trauma. The MRI parameters included disc bulging either with impingement on the anterior epidural space or with medullary compression, foraminal stenosis, dorsal ligament thickening, osteophyte extension and intramedullary or paravertebral soft tissue injury. All changes were graded visually on a four-point scale (no, some, moderate or extensive changes). After the MRI evaluation was made the clinical findings were analysed by two orthopaedic surgeons using a specially designed protocol. With MRI 29 patients (74 %) showed no or only slight changes, and were thus regarded as normal variations. Of these, 10 of 29 patients (34 %) had as the only symptom pain in the head or in the neck, 19 of 29 patients (66 %) showed neurological changes, either paresthesias, sensory deficits or weakness of upper extremities. In 10 (26 %) patients with moderate or extensive MRI changes, 3 of 10 (33 %) had only head or neck pain, or both, and 7 of 10 (66 %) had neurological changes. Use of MRI in whiplash injury is helpful, but it is not the first-choice radiological examination method. Despite neurological changes, the frequency of true traumatic lesions is low. There is no clear correlation between the patients` subjective symptoms or clinical signs and the findings with MRI. However, MRI can be used to find patients with disk herniation that can be treated surgically. (orig.)

  13. MRI in acute phase of whiplash injury

    International Nuclear Information System (INIS)

    Fagerlund, M.; Bjoernebrink, J.; Pettersson, K.; Hildingsson, C.

    1995-01-01

    A prospective MRI study of 39 whiplash patients was performed and the results were compared with the clinical findings within 15 days after trauma. The MRI parameters included disc bulging either with impingement on the anterior epidural space or with medullary compression, foraminal stenosis, dorsal ligament thickening, osteophyte extension and intramedullary or paravertebral soft tissue injury. All changes were graded visually on a four-point scale (no, some, moderate or extensive changes). After the MRI evaluation was made the clinical findings were analysed by two orthopaedic surgeons using a specially designed protocol. With MRI 29 patients (74 %) showed no or only slight changes, and were thus regarded as normal variations. Of these, 10 of 29 patients (34 %) had as the only symptom pain in the head or in the neck, 19 of 29 patients (66 %) showed neurological changes, either paresthesias, sensory deficits or weakness of upper extremities. In 10 (26 %) patients with moderate or extensive MRI changes, 3 of 10 (33 %) had only head or neck pain, or both, and 7 of 10 (66 %) had neurological changes. Use of MRI in whiplash injury is helpful, but it is not the first-choice radiological examination method. Despite neurological changes, the frequency of true traumatic lesions is low. There is no clear correlation between the patients' subjective symptoms or clinical signs and the findings with MRI. However, MRI can be used to find patients with disk herniation that can be treated surgically. (orig.)

  14. Quantifying diffusion MRI tractography of the corticospinal tract in brain tumors with deterministic and probabilistic methods.

    Science.gov (United States)

    Bucci, Monica; Mandelli, Maria Luisa; Berman, Jeffrey I; Amirbekian, Bagrat; Nguyen, Christopher; Berger, Mitchel S; Henry, Roland G

    2013-01-01

    sensitivity (79%) as determined from cortical IES compared to deterministic q-ball (50%), probabilistic DTI (36%), and deterministic DTI (10%). The sensitivity using the q-ball algorithm (65%) was significantly higher than using DTI (23%) (p probabilistic algorithms (58%) were more sensitive than deterministic approaches (30%) (p = 0.003). Probabilistic q-ball fiber tracks had the smallest offset to the subcortical stimulation sites. The offsets between diffusion fiber tracks and subcortical IES sites were increased significantly for those cases where the diffusion fiber tracks were visibly thinner than expected. There was perfect concordance between the subcortical IES function (e.g. hand stimulation) and the cortical connection of the nearest diffusion fiber track (e.g. upper extremity cortex). This study highlights the tremendous utility of intraoperative stimulation sites to provide a gold standard from which to evaluate diffusion MRI fiber tracking methods and has provided an object standard for evaluation of different diffusion models and approaches to fiber tracking. The probabilistic q-ball fiber tractography was significantly better than DTI methods in terms of sensitivity and accuracy of the course through the white matter. The commonly used DTI fiber tracking approach was shown to have very poor sensitivity (as low as 10% for deterministic DTI fiber tracking) for delineation of the lateral aspects of the corticospinal tract in our study. Effects of the tumor/edema resulted in significantly larger offsets between the subcortical IES and the preoperative fiber tracks. The provided data show that probabilistic HARDI tractography is the most objective and reproducible analysis but given the small sample and number of stimulation points a generalization about our results should be given with caution. Indeed our results inform the capabilities of preoperative diffusion fiber tracking and indicate that such data should be used carefully when making pre-surgical and

  15. Comparison of in vivo vs. frozen vs. Thiel cadaver specimens in visualisation of anatomical structures of the ankle on proton density Magnetic Resonance Imaging (MRI) through a visual grading analysis (VGA) study

    International Nuclear Information System (INIS)

    Zarb, F.; McNulty, J.; Gatt, A.; Formosa, C.; Chockalingam, N.; Evanoff, M.G.; Rainford, L.

    2017-01-01

    Purpose: The use of cadavers for medical education purposes and for radiology research methodologies which involve subjective image quality evaluation of anatomical criteria is well documented. The aim of this study was to quantify the impact of cadaver tissue preservation in producing MR images that are representative of living tissue by comparing the visualisation of anatomical structures of the ankle obtained from live and cadaver (fresh frozen and Thiel embalmed) specimens through a visual grading analysis (VGA) study. Methods: A VGA study was conducted on an image data set consisting of 4 coronal proton density weighted (PDw) sequences obtained from ankles of a live patient and those of a cadaveric specimen, of which the right ankle was frozen and the left Thiel embalmed. Results: Comparison of the image quality scores obtained from: the live patient vs. the Thiel specimen indicate a significant difference (p ≤ 0.05) between the scores in favour of the Thiel specimen; between the live patient vs. the frozen specimen indicate a significant difference (p ≤ 0.05) in favour of the frozen specimen and between the frozen vs. the Thiel specimen indicate a significant difference (p ≤ 0.05) in favour of the Thiel specimen. Conclusions: The advantages of the use of cadavers (frozen or Thiel embalmed) has been shown to also apply for use with proton density (PD) MR imaging. The preservation of cadavers especially using Thiel is a suitable alternative for MRI optimisation and protocol development purposes. - Highlights: • Thiel preservation: a better alternative compared to frozen methods for MR image analysis. • VGA demonstrated an efficient research study design for the investigation of embalming methods. • Thiel embalmed cadavers: an acceptable alternative from patients for MR imaging optimisation. • Additional MR sequences and increased sample sizes are recommended for further investigation.

  16. High-grade MRI bone oedema is common within the surgical field in rheumatoid arthritis patients undergoing joint replacement and is associated with osteitis in subchondral bone

    DEFF Research Database (Denmark)

    McQueen, F M; Gao, A; Ostergaard, M

    2007-01-01

    OBJECTIVES: MRI bone oedema has been observed in early and advanced RA and may represent a cellular infiltrate (osteitis) in subchondral bone. We studied MRI scans from RA patients undergoing surgery, seeking to identify regions of bone oedema and examine its histopathological equivalent in resec...

  17. A semi-automatic method for developing an anthropomorphic numerical model of dielectric anatomy by MRI

    International Nuclear Information System (INIS)

    Mazzurana, M; Sandrini, L; Vaccari, A; Malacarne, C; Cristoforetti, L; Pontalti, R

    2003-01-01

    Complex permittivity values have a dominant role in the overall consideration of interaction between radiofrequency electromagnetic fields and living matter, and in related applications such as electromagnetic dosimetry. There are still some concerns about the accuracy of published data and about their variability due to the heterogeneous nature of biological tissues. The aim of this study is to provide an alternative semi-automatic method by which numerical dielectric human models for dosimetric studies can be obtained. Magnetic resonance imaging (MRI) tomography was used to acquire images. A new technique was employed to correct nonuniformities in the images and frequency-dependent transfer functions to correlate image intensity with complex permittivity were used. The proposed method provides frequency-dependent models in which permittivity and conductivity vary with continuity-even in the same tissue-reflecting the intrinsic realistic spatial dispersion of such parameters. The human model is tested with an FDTD (finite difference time domain) algorithm at different frequencies; the results of layer-averaged and whole-body-averaged SAR (specific absorption rate) are compared with published work, and reasonable agreement has been found. Due to the short time needed to obtain a whole body model, this semi-automatic method may be suitable for efficient study of various conditions that can determine large differences in the SAR distribution, such as body shape, posture, fat-to-muscle ratio, height and weight

  18. Materials and methods for higher performance screen-printed flexible MRI receive coils.

    Science.gov (United States)

    Corea, Joseph R; Lechene, P Balthazar; Lustig, Michael; Arias, Ana C

    2017-08-01

    To develop methods for characterizing materials used in screen-printed MRI coils and improve signal-to-noise ratio (SNR) with new lower-loss materials. An experimental apparatus was created to characterize dielectric properties of plastic substrates used in receive coils. Coils were fabricated by screen printing conductive ink onto several plastic substrates. Unloaded and sample loaded quality factor (Q Unloaded /Q Loaded ) measurements and scans on a 3T scanner were used to characterize coil performance. An experimental method was developed to describe the relationship between a coil's Q Unloaded and the SNR it provides in images of a phantom. In addition, 3T scans of a phantom and the head of a volunteer were obtained with a proof-of-concept printed eight-channel array, and the results were compared with a commercial 12-channel array. Printed coils with optimized substrates exhibited up to 97% of the image SNR when compared with a traditional coil on a loading phantom. Q Unloaded and the SNR of coils were successfully correlated. The printed array resulted in images comparable to the quality given by the commercial array. Using the proposed methods and materials, the SNR of printed coils approached that of commercial coils while using a new fabrication technique that provided more flexibility and close contact with the patient's body. Magn Reson Med 78:775-783, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  19. A primal–dual hybrid gradient method for nonlinear operators with applications to MRI

    KAUST Repository

    Valkonen, Tuomo

    2014-05-01

    We study the solution of minimax problems min xmax yG(x) + K(x), y - F*(y) in finite-dimensional Hilbert spaces. The functionals G and F* we assume to be convex, but the operator K we allow to be nonlinear. We formulate a natural extension of the modified primal-dual hybrid gradient method, originally for linear K, due to Chambolle and Pock. We prove the local convergence of the method, provided various technical conditions are satisfied. These include in particular the Aubin property of the inverse of a monotone operator at the solution. Of particular interest to us is the case arising from Tikhonov type regularization of inverse problems with nonlinear forward operators. Mainly we are interested in total variation and second-order total generalized variation priors. For such problems, we show that our general local convergence result holds when the noise level of the data f is low, and the regularization parameter α is correspondingly small. We verify the numerical performance of the method by applying it to problems from magnetic resonance imaging (MRI) in chemical engineering and medicine. The specific applications are in diffusion tensor imaging and MR velocity imaging. These numerical studies show very promising performance. © 2014 IOP Publishing Ltd.

  20. Breast MRI, digital mammography and breast tomosynthesis: comparison of three methods for early detection of breast cancer.

    Science.gov (United States)

    Roganovic, Dragana; Djilas, Dragana; Vujnovic, Sasa; Pavic, Dag; Stojanov, Dragan

    2015-11-16

    Breast cancer is the most common malignancy in women and early detection is important for its successful treatment. The aim of this study was to investigate the sensitivity and specificity of three methods for early detection of breast cancer: breast magnetic resonance imaging (MRI), digital mammography, and breast tomosynthesis in comparison to histopathology, as well as to investigate the intraindividual variability between these modalities. We included 57 breast lesions, each detected by three diagnostic modalities: digital mammography, breast MRI, and breast tomosynthesis, and subsequently confirmed by histopathology. Breast Imaging-Reporting and Data System (BI-RADS) was used for characterizing the lesions. One experienced radiologist interpreted all three diagnostic modalities. Twenty-nine of the breast lesions were malignant while 28 were benign. The sensitivity for digital mammography, breast MRI, and breast tomosynthesis, was 72.4%, 93.1%, and 100%, respectively; while the specificity was 46.4%, 60.7%, and 75%, respectively. Receiver operating characteristics (ROC) curve analysis showed an overall diagnostic advantage of breast tomosynthesis over both breast MRI and digital mammography. The difference in performance between breast tomosynthesis and digital mammography was significant (p tomosynthesis and breast MRI was not significant (p=0.20).

  1. Breast MRI, digital mammography and breast tomosynthesis: comparison of three methods for early detection of breast cancer

    Directory of Open Access Journals (Sweden)

    Dragana Roganovic

    2015-11-01

    Full Text Available Breast cancer is the most common malignancy in women and early detection is important for its successful treatment. The aim of this study was to investigate the sensitivity and specificity of three methods for early detection of breast cancer: breast magnetic resonance imaging (MRI, digital mammography, and breast tomosynthesis in comparison to histopathology, as well as to investigate the intraindividual variability between these modalities.  We included 57 breast lesions, each detected by three diagnostic modalities: digital mammography, breast MRI, and breast tomosynthesis, and subsequently confirmed by histopathology. Breast Imaging-Reporting and Data System (BI-RADS was used for characterizing the lesions. One experienced radiologist interpreted all three diagnostic modalities. Twenty-nine of the breast lesions were malignant while 28 were benign. The sensitivity for digital mammography, breast MRI, and breast tomosynthesis, was 72.4%, 93.1%, and 100%, respectively; while the specificity was 46.4%, 60.7%, and 75%, respectively. Receiver operating characteristics (ROC curve analysis showed an overall diagnostic advantage of breast tomosynthesis over both breast MRI and digital mammography. The difference in performance between breast tomosynthesis and digital mammography was significant (p < 0.001, while the difference between breast tomosynthesis and breast MRI was not significant (p = 0.20. 

  2. Analysis of macro and micro residual stresses in functionally graded materials by diffraction methods

    CERN Document Server

    Dantz, D; Reimers, W

    1999-01-01

    The residual stress state in microwave sintered metal-ceramic functionally graded materials (FGM) consisting of 8Y-ZrO/sub 2//Ni and 8Y-ZrO/sub 2//NiCr8020, respectively, was analysed by non- destructive diffraction methods. In $9 order to get knowledge of the complete residual stress state in the near surface region as well as in the interior of the material, complementary methods were applied. Whereas the surface was characterised by X-ray techniques using $9 conventional sources, the stresses within the bulk of the material were investigated by means of high energy synchrotron radiation. The stress state was found to obey the differences in the coefficients of thermal expansion $9 (micro-stresses) on the one hand and the inhomogeneous cooling conditions (macrostresses) on the other hand. (7 refs).

  3. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

  4. Love waves in functionally graded piezoelectric materials by stiffness matrix method.

    Science.gov (United States)

    Ben Salah, Issam; Wali, Yassine; Ben Ghozlen, Mohamed Hédi

    2011-04-01

    A numerical matrix method relative to the propagation of ultrasonic guided waves in functionally graded piezoelectric heterostructure is given in order to make a comparative study with the respective performances of analytical methods proposed in literature. The preliminary obtained results show a good agreement, however numerical approach has the advantage of conceptual simplicity and flexibility brought about by the stiffness matrix method. The propagation behaviour of Love waves in a functionally graded piezoelectric material (FGPM) is investigated in this article. It involves a thin FGPM layer bonded perfectly to an elastic substrate. The inhomogeneous FGPM heterostructure has been stratified along the depth direction, hence each state can be considered as homogeneous and the ordinary differential equation method is applied. The obtained solutions are used to study the effect of an exponential gradient applied to physical properties. Such numerical approach allows applying different gradient variation for mechanical and electrical properties. For this case, the obtained results reveal opposite effects. The dispersive curves and phase velocities of the Love wave propagation in the layered piezoelectric film are obtained for electrical open and short cases on the free surface, respectively. The effect of gradient coefficients on coupled electromechanical factor, on the stress fields, the electrical potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the well known heterostructure PZT-5H/SiO(2), the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Love wave propagation behaviour. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Arthroscopy vs. MRI for a detailed assessment of cartilage disease in osteoarthritis: diagnostic value of MRI in clinical practice

    Directory of Open Access Journals (Sweden)

    Haage Patrick

    2010-04-01

    Full Text Available Abstract Background In patients with osteoarthritis, a detailed assessment of degenerative cartilage disease is important to recommend adequate treatment. Using a representative sample of patients, this study investigated whether MRI is reliable for a detailed cartilage assessment in patients with osteoarthritis of the knee. Methods In a cross sectional-study as a part of a retrospective case-control study, 36 patients (mean age 53.1 years with clinically relevant osteoarthritis received standardized MRI (sag. T1-TSE, cor. STIR-TSE, trans. fat-suppressed PD-TSE, sag. fat-suppressed PD-TSE, Siemens Magnetom Avanto syngo MR B 15 on a 1.5 Tesla unit. Within a maximum of three months later, arthroscopic grading of the articular surfaces was performed. MRI grading by two blinded observers was compared to arthroscopic findings. Diagnostic values as well as intra- and inter-observer values were assessed. Results Inter-observer agreement between readers 1 and 2 was good (kappa = 0.65 within all compartments. Intra-observer agreement comparing MRI grading to arthroscopic grading showed moderate to good values for readers 1 and 2 (kappa = 0.50 and 0.62, respectively, the poorest being within the patellofemoral joint (kappa = 0.32 and 0.52. Sensitivities were relatively low at all grades, particularly for grade 3 cartilage lesions. A tendency to underestimate cartilage disorders on MR images was not noticed. Conclusions According to our results, the use of MRI for precise grading of the cartilage in osteoarthritis is limited. Even if the practical benefit of MRI in pretreatment diagnostics is unequivocal, a diagnostic arthroscopy is of outstanding value when a grading of the cartilage is crucial for a definitive decision regarding therapeutic options in patients with osteoarthritis.

  6. An analytical method for free vibration analysis of functionally graded beams with edge cracks

    Science.gov (United States)

    Wei, Dong; Liu, Yinghua; Xiang, Zhihai

    2012-03-01

    In this paper, an analytical method is proposed for solving the free vibration of cracked functionally graded material (FGM) beams with axial loading, rotary inertia and shear deformation. The governing differential equations of motion for an FGM beam are established and the corresponding solutions are found first. The discontinuity of rotation caused by the cracks is simulated by means of the rotational spring model. Based on the transfer matrix method, then the recurrence formula is developed to get the eigenvalue equations of free vibration of FGM beams. The main advantage of the proposed method is that the eigenvalue equation for vibrating beams with an arbitrary number of cracks can be conveniently determined from a third-order determinant. Due to the decrease in the determinant order as compared with previous methods, the developed method is simpler and more convenient to analytically solve the free vibration problem of cracked FGM beams. Moreover, free vibration analyses of the Euler-Bernoulli and Timoshenko beams with any number of cracks can be conducted using the unified procedure based on the developed method. These advantages of the proposed procedure would be more remarkable as the increase of the number of cracks. A comprehensive analysis is conducted to investigate the influences of the location and total number of cracks, material properties, axial load, inertia and end supports on the natural frequencies and vibration mode shapes of FGM beams. The present work may be useful for the design and control of damaged structures.

  7. A numerical test method of California bearing ratio on graded crushed rocks using particle flow modeling

    Directory of Open Access Journals (Sweden)

    Yingjun Jiang

    2015-04-01

    Full Text Available In order to better understand the mechanical properties of graded crushed rocks (GCRs and to optimize the relevant design, a numerical test method based on the particle flow modeling technique PFC2D is developed for the California bearing ratio (CBR test on GCRs. The effects of different testing conditions and micro-mechanical parameters used in the model on the CBR numerical results have been systematically studied. The reliability of the numerical technique is verified. The numerical results suggest that the influences of the loading rate and Poisson's ratio on the CBR numerical test results are not significant. As such, a loading rate of 1.0–3.0 mm/min, a piston diameter of 5 cm, a specimen height of 15 cm and a specimen diameter of 15 cm are adopted for the CBR numerical test. The numerical results reveal that the CBR values increase with the friction coefficient at the contact and shear modulus of the rocks, while the influence of Poisson's ratio on the CBR values is insignificant. The close agreement between the CBR numerical results and experimental results suggests that the numerical simulation of the CBR values is promising to help assess the mechanical properties of GCRs and to optimize the grading design. Besides, the numerical study can provide useful insights on the mesoscopic mechanism.

  8. Comparative study of SVM methods combined with voxel selection for object category classification on fMRI data.

    Science.gov (United States)

    Song, Sutao; Zhan, Zhichao; Long, Zhiying; Zhang, Jiacai; Yao, Li

    2011-02-16

    Support vector machine (SVM) has been widely used as accurate and reliable method to decipher brain patterns from functional MRI (fMRI) data. Previous studies have not found a clear benefit for non-linear (polynomial kernel) SVM versus linear one. Here, a more effective non-linear SVM using radial basis function (RBF) kernel is compared with linear SVM. Different from traditional studies which focused either merely on the evaluation of different types of SVM or the voxel selection methods, we aimed to investigate the overall performance of linear and RBF SVM for fMRI classification together with voxel selection schemes on classification accuracy and time-consuming. Six different voxel selection methods were employed to decide which voxels of fMRI data would be included in SVM classifiers with linear and RBF kernels in classifying 4-category objects. Then the overall performances of voxel selection and classification methods were compared. Results showed that: (1) Voxel selection had an important impact on the classification accuracy of the classifiers: in a relative low dimensional feature space, RBF SVM outperformed linear SVM significantly; in a relative high dimensional space, linear SVM performed better than its counterpart; (2) Considering the classification accuracy and time-consuming holistically, linear SVM with relative more voxels as features and RBF SVM with small set of voxels (after PCA) could achieve the better accuracy and cost shorter time. The present work provides the first empirical result of linear and RBF SVM in classification of fMRI data, combined with voxel selection methods. Based on the findings, if only classification accuracy was concerned, RBF SVM with appropriate small voxels and linear SVM with relative more voxels were two suggested solutions; if users concerned more about the computational time, RBF SVM with relative small set of voxels when part of the principal components were kept as features was a better choice.

  9. A wavelet method for modeling and despiking motion artifacts from resting-state fMRI time series

    Science.gov (United States)

    Patel, Ameera X.; Kundu, Prantik; Rubinov, Mikail; Jones, P. Simon; Vértes, Petra E.; Ersche, Karen D.; Suckling, John; Bullmore, Edward T.

    2014-01-01

    The impact of in-scanner head movement on functional magnetic resonance imaging (fMRI) signals has long been established as undesirable. These effects have been traditionally corrected by methods such as linear regression of head movement parameters. However, a number of recent independent studies have demonstrated that these techniques are insufficient to remove motion confounds, and that even small movements can spuriously bias estimates of functional connectivity. Here we propose a new data-driven, spatially-adaptive, wavelet-based method for identifying, modeling, and removing non-stationary events in fMRI time series, caused by head movement, without the need for data scrubbing. This method involves the addition of just one extra step, the Wavelet Despike, in standard pre-processing pipelines. With this method, we demonstrate robust removal of a range of different motion artifacts and motion-related biases including distance-dependent connectivity artifacts, at a group and single-subject level, using a range of previously published and new diagnostic measures. The Wavelet Despike is able to accommodate the substantial spatial and temporal heterogeneity of motion artifacts and can consequently remove a range of high and low frequency artifacts from fMRI time series, that may be linearly or non-linearly related to physical movements. Our methods are demonstrated by the analysis of three cohorts of resting-state fMRI data, including two high-motion datasets: a previously published dataset on children (N = 22) and a new dataset on adults with stimulant drug dependence (N = 40). We conclude that there is a real risk of motion-related bias in connectivity analysis of fMRI data, but that this risk is generally manageable, by effective time series denoising strategies designed to attenuate synchronized signal transients induced by abrupt head movements. The Wavelet Despiking software described in this article is freely available for download at www

  10. A wavelet method for modeling and despiking motion artifacts from resting-state fMRI time series.

    Science.gov (United States)

    Patel, Ameera X; Kundu, Prantik; Rubinov, Mikail; Jones, P Simon; Vértes, Petra E; Ersche, Karen D; Suckling, John; Bullmore, Edward T

    2014-07-15

    The impact of in-scanner head movement on functional magnetic resonance imaging (fMRI) signals has long been established as undesirable. These effects have been traditionally corrected by methods such as linear regression of head movement parameters. However, a number of recent independent studies have demonstrated that these techniques are insufficient to remove motion confounds, and that even small movements can spuriously bias estimates of functional connectivity. Here we propose a new data-driven, spatially-adaptive, wavelet-based method for identifying, modeling, and removing non-stationary events in fMRI time series, caused by head movement, without the need for data scrubbing. This method involves the addition of just one extra step, the Wavelet Despike, in standard pre-processing pipelines. With this method, we demonstrate robust removal of a range of different motion artifacts and motion-related biases including distance-dependent connectivity artifacts, at a group and single-subject level, using a range of previously published and new diagnostic measures. The Wavelet Despike is able to accommodate the substantial spatial and temporal heterogeneity of motion artifacts and can consequently remove a range of high and low frequency artifacts from fMRI time series, that may be linearly or non-linearly related to physical movements. Our methods are demonstrated by the analysis of three cohorts of resting-state fMRI data, including two high-motion datasets: a previously published dataset on children (N=22) and a new dataset on adults with stimulant drug dependence (N=40). We conclude that there is a real risk of motion-related bias in connectivity analysis of fMRI data, but that this risk is generally manageable, by effective time series denoising strategies designed to attenuate synchronized signal transients induced by abrupt head movements. The Wavelet Despiking software described in this article is freely available for download at www

  11. A novel anisotropic fast marching method and its application to blood flow computation in phase-contrast MRI.

    Science.gov (United States)

    Schwenke, M; Hennemuth, A; Fischer, B; Friman, O

    2012-01-01

    Phase-contrast MRI (PC MRI) can be used to assess blood flow dynamics noninvasively inside the human body. The acquired images can be reconstructed into flow vector fields. Traditionally, streamlines can be computed based on the vector fields to visualize flow patterns and particle trajectories. The traditional methods may give a false impression of precision, as they do not consider the measurement uncertainty in the PC MRI images. In our prior work, we incorporated the uncertainty of the measurement into the computation of particle trajectories. As a major part of the contribution, a novel numerical scheme for solving the anisotropic Fast Marching problem is presented. A computing time comparison to state-of-the-art methods is conducted on artificial tensor fields. A visual comparison of healthy to pathological blood flow patterns is given. The comparison shows that the novel anisotropic Fast Marching solver outperforms previous schemes in terms of computing time. The visual comparison of flow patterns directly visualizes large deviations of pathological flow from healthy flow. The novel anisotropic Fast Marching solver efficiently resolves even strongly anisotropic path costs. The visualization method enables the user to assess the uncertainty of particle trajectories derived from PC MRI images.

  12. A method to determine the necessity for global signal regression in resting-state fMRI studies.

    Science.gov (United States)

    Chen, Gang; Chen, Guangyu; Xie, Chunming; Ward, B Douglas; Li, Wenjun; Antuono, Piero; Li, Shi-Jiang

    2012-12-01

    In resting-state functional MRI studies, the global signal (operationally defined as the global average of resting-state functional MRI time courses) is often considered a nuisance effect and commonly removed in preprocessing. This global signal regression method can introduce artifacts, such as false anticorrelated resting-state networks in functional connectivity analyses. Therefore, the efficacy of this technique as a correction tool remains questionable. In this article, we establish that the accuracy of the estimated global signal is determined by the level of global noise (i.e., non-neural noise that has a global effect on the resting-state functional MRI signal). When the global noise level is low, the global signal resembles the resting-state functional MRI time courses of the largest cluster, but not those of the global noise. Using real data, we demonstrate that the global signal is strongly correlated with the default mode network components and has biological significance. These results call into question whether or not global signal regression should be applied. We introduce a method to quantify global noise levels. We show that a criteria for global signal regression can be found based on the method. By using the criteria, one can determine whether to include or exclude the global signal regression in minimizing errors in functional connectivity measures. Copyright © 2012 Wiley Periodicals, Inc.

  13. Assessment of myocardial perfusion with MRI using a modified dual bolus method

    International Nuclear Information System (INIS)

    Husso, M; Sipola, P; Manninen, H; Vainio, P; Kuittinen, T; Hartikainen, J; Saarakkala, S; Töyräs, J; Kuikka, J

    2014-01-01

    Quantification of regional myocardial blood flow (rMBF) with first-pass magnetic resonance imaging (FP-MRI) requires two contrast agent injections (dual bolus technique), inducing error in the determined rMBF if the injections differ. We hypothesize that using input and residue curves of the same injection would be more reliable. We aim to introduce and evaluate a novel method to correct the high concentration arterial input function (AIF) for determination of rMBF. Sixteen patients with non-Hodgkin's lymphoma were examined before and after chemotherapy. The input function was solved by correcting initial high concentration AIF using the ratio of low and high contrast AIF areas, normalized by corresponding heart rates (modified dual bolus method). For comparison, the scaled low contrast AIF was used as an input function (dual bolus method). Unidirectional transfer coefficient K trans  was calculated using both methods. K trans -values determined with the dual bolus (0.81 ± 0.32 ml g −1  min −1 ) and modified dual bolus (0.77 ± 0.42 ml g −1  min −1 ) methods were in agreement (p = 0.21). Mean K trans -values increased from 0.76 ± 0.43 to 0.89 ± 0.55 ml g −1  min −1  after chemotherapy (p = 0.17). The modified dual bolus technique agrees with the dual bolus technique (R2 = 0.899) when the low and high contrast injections are similar. However, when this is not the case, the modified dual bolus technique may be more reliable. (paper)

  14. Preparation of High-Grade Powders from Tomato Paste Using a Vacuum Foam Drying Method.

    Science.gov (United States)

    Sramek, Martin; Schweiggert, Ralf Martin; van Kampen, Andreas; Carle, Reinhold; Kohlus, Reinhard

    2015-08-01

    We present a rapid and gentle drying method for the production of high-grade tomato powders from double concentrated tomato paste, comparing results with powders obtained by foam mat air drying and freeze dried powders. The principle of this method consists of drying tomato paste in foamed state at low temperatures in vacuum. The formulations were dried at temperatures of 50, 60, and 70 °C and vacuum of 200 mbar. Foam stability was affected by low serum viscosity and the presence of solid particles in tomato paste. Consequently, serum viscosity was increased by maltodextrin addition, yielding optimum stability at tomato paste:maltodextrin ratio of 2.4:1 (w/w) in dry matter. Material foamability was improved by addition of 0.5% (w/w, fresh weight) egg white. Because of solid particles in tomato paste, foam air filling had to be limited to critical air volume fraction of Φ = 0.7. The paste was first pre-foamed to Φ = 0.2 and subsequently expanded in vacuo. After drying to a moisture content of 5.6% to 7.5% wet base (w.b.), the materials obtained were in glassy state. Qualities of the resulting powders were compared with those produced by freeze and air drying. Total color changes were the least after vacuum drying, whereas air drying resulted in noticeable color changes. Vacuum foam drying at 50 °C led to insignificant carotenoid losses, being equivalent to the time-consuming freeze drying method. In contrast, air drying caused lycopene and β-carotene losses of 18% to 33% and 14% to 19% respectively. Thus, vacuum foam drying enables production of high-grade tomato powders being qualitatively similar to powders obtained by freeze drying. © 2015 Institute of Food Technologists®

  15. Analysis of Dynamic Fracture Parameters in Functionally Graded Material Plates with Cracks by Graded Finite Element Method and Virtual Crack Closure Technique

    Directory of Open Access Journals (Sweden)

    Li Ming Zhou

    2016-01-01

    Full Text Available Based on the finite element software ABAQUS and graded element method, we developed a dummy node fracture element, wrote the user subroutines UMAT and UEL, and solved the energy release rate component of functionally graded material (FGM plates with cracks. An interface element tailored for the virtual crack closure technique (VCCT was applied. Fixed cracks and moving cracks under dynamic loads were simulated. The results were compared to other VCCT-based analyses. With the implementation of a crack speed function within the element, it can be easily expanded to the cases of varying crack velocities, without convergence difficulty for all cases. Neither singular element nor collapsed element was required. Therefore, due to its simplicity, the VCCT interface element is a potential tool for engineers to conduct dynamic fracture analysis in conjunction with commercial finite element analysis codes.

  16. A multi-atlas based method for automated anatomical Macaca fascicularis brain MRI segmentation and PET kinetic extraction.

    Science.gov (United States)

    Ballanger, Bénédicte; Tremblay, Léon; Sgambato-Faure, Véronique; Beaudoin-Gobert, Maude; Lavenne, Franck; Le Bars, Didier; Costes, Nicolas

    2013-08-15

    MRI templates and digital atlases are needed for automated and reproducible quantitative analysis of non-human primate PET studies. Segmenting brain images via multiple atlases outperforms single-atlas labelling in humans. We present a set of atlases manually delineated on brain MRI scans of the monkey Macaca fascicularis. We use this multi-atlas dataset to evaluate two automated methods in terms of accuracy, robustness and reliability in segmenting brain structures on MRI and extracting regional PET measures. Twelve individual Macaca fascicularis high-resolution 3DT1 MR images were acquired. Four individual atlases were created by manually drawing 42 anatomical structures, including cortical and sub-cortical structures, white matter regions, and ventricles. To create the MRI template, we first chose one MRI to define a reference space, and then performed a two-step iterative procedure: affine registration of individual MRIs to the reference MRI, followed by averaging of the twelve resampled MRIs. Automated segmentation in native space was obtained in two ways: 1) Maximum probability atlases were created by decision fusion of two to four individual atlases in the reference space, and transformation back into the individual native space (MAXPROB)(.) 2) One to four individual atlases were registered directly to the individual native space, and combined by decision fusion (PROPAG). Accuracy was evaluated by computing the Dice similarity index and the volume difference. The robustness and reproducibility of PET regional measurements obtained via automated segmentation was evaluated on four co-registered MRI/PET datasets, which included test-retest data. Dice indices were always over 0.7 and reached maximal values of 0.9 for PROPAG with all four individual atlases. There was no significant mean volume bias. The standard deviation of the bias decreased significantly when increasing the number of individual atlases. MAXPROB performed better when increasing the number of

  17. Evaluation of MRI acquisition workflow with lean six sigma method: case study of liver and knee examinations.

    Science.gov (United States)

    Roth, Christopher J; Boll, Daniel T; Wall, Lisa K; Merkle, Elmar M

    2010-08-01

    The purpose of this investigation was to assess workflow for medical imaging studies, specifically comparing liver and knee MRI examinations by use of the Lean Six Sigma methodologic framework. The hypothesis tested was that the Lean Six Sigma framework can be used to quantify MRI workflow and to identify sources of inefficiency to target for sequence and protocol improvement. Audio-video interleave streams representing individual acquisitions were obtained with graphic user interface screen capture software in the examinations of 10 outpatients undergoing MRI of the liver and 10 outpatients undergoing MRI of the knee. With Lean Six Sigma methods, the audio-video streams were dissected into value-added time (true image data acquisition periods), business value-added time (time spent that provides no direct patient benefit but is requisite in the current system), and non-value-added time (scanner inactivity while awaiting manual input). For overall MRI table time, value-added time was 43.5% (range, 39.7-48.3%) of the time for liver examinations and 89.9% (range, 87.4-93.6%) for knee examinations. Business value-added time was 16.3% of the table time for the liver and 4.3% of the table time for the knee examinations. Non-value-added time was 40.2% of the overall table time for the liver and 5.8% for the knee examinations. Liver MRI examinations consume statistically significantly more non-value-added and business value-added times than do knee examinations, primarily because of respiratory command management and contrast administration. Workflow analyses and accepted inefficiency reduction frameworks can be applied with use of a graphic user interface screen capture program.

  18. Method of purifying metallurgical grade silicon employing reduced pressure atmospheric control

    Science.gov (United States)

    Ingle, W. M.; Thompson, S. W.; Chaney, R. E. (Inventor)

    1979-01-01

    A method in which a quartz tube is charged with chunks of metallurgical grade silicon and/or a mixture of such chunks and high purity quartz sand, and impurities from a class including aluminum, boron, as well as certain transition metals including nickel, iron, and manganese is described. The tube is then evacuated and heated to a temperature within a range of 800 C to 1400 C. A stream of gas comprising a reactant, such as silicon tetrafluoride, is continuously delivered at low pressures through the charge for causing a metathetical reaction of impurities of the silicon and the reactant to occur for forming a volatile halide and leaving a residue of silicon of an improved purity. The reactant which included carbon monoxide gas and impurities such as iron and nickel react to form volatile carbonyls.

  19. Transverse vibration of pipe conveying fluid made of functionally graded materials using a symplectic method

    International Nuclear Information System (INIS)

    Wang, Zhong-Min; Liu, Yan-Zhuang

    2016-01-01

    Highlights: • We investigate the transverse vibration of FGM pipe conveying fluid. • The FGM pipe conveying fluid can be classified into two cases. • The variations between the frequency and the power law exponent are obtained. • “Case 1” is relatively more reasonable than “case 2”. - Abstract: Problems related to the transverse vibration of pipe conveying fluid made of functionally graded material (FGM) are addressed. Based on inside and outside surface material compositions of the pipe, FGM pipe conveying fluid can be classified into two cases. It is hypothesized that the physical parameters of the material along the direction of the pipe wall thickness change in the simple power law. A differential equation of motion expressed in non-dimensional quantities is derived by using Hamilton's principle for systems of changing mass. Using the assuming modal method, the pipe deflection function is expanded into a series, in which each term is expressed to admissible function multiplied by generalized coordinate. Then, the differential equation of motion is discretized into the two order differential equations expressed in the generalized coordinates. Based on symplectic elastic theory and the introduction of dual system and dual variable, Hamilton's dual equations are derived, and the original problem is reduced to eigenvalue and eigenvector problem in the symplectic space. Finally, a symplectic method is employed to analyze the vibration and stability of FGM pipe conveying fluid. For a clamped–clamped FGM pipe conveying fluid in “case 1” and “case 2”, the dimensionless critical flow velocity for first-mode divergence and the critical coupled-mode flutter flow velocity are obtained, and the variations between the real part and imaginary part of dimensionless complex frequency and fluid velocity, mass ratio and the power law exponent (or graded index, volume fraction) for FGM pipe conveying fluid are analyzed.

  20. Transverse vibration of pipe conveying fluid made of functionally graded materials using a symplectic method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhong-Min, E-mail: wangzhongm@xaut.edu.cn; Liu, Yan-Zhuang

    2016-03-15

    Highlights: • We investigate the transverse vibration of FGM pipe conveying fluid. • The FGM pipe conveying fluid can be classified into two cases. • The variations between the frequency and the power law exponent are obtained. • “Case 1” is relatively more reasonable than “case 2”. - Abstract: Problems related to the transverse vibration of pipe conveying fluid made of functionally graded material (FGM) are addressed. Based on inside and outside surface material compositions of the pipe, FGM pipe conveying fluid can be classified into two cases. It is hypothesized that the physical parameters of the material along the direction of the pipe wall thickness change in the simple power law. A differential equation of motion expressed in non-dimensional quantities is derived by using Hamilton's principle for systems of changing mass. Using the assuming modal method, the pipe deflection function is expanded into a series, in which each term is expressed to admissible function multiplied by generalized coordinate. Then, the differential equation of motion is discretized into the two order differential equations expressed in the generalized coordinates. Based on symplectic elastic theory and the introduction of dual system and dual variable, Hamilton's dual equations are derived, and the original problem is reduced to eigenvalue and eigenvector problem in the symplectic space. Finally, a symplectic method is employed to analyze the vibration and stability of FGM pipe conveying fluid. For a clamped–clamped FGM pipe conveying fluid in “case 1” and “case 2”, the dimensionless critical flow velocity for first-mode divergence and the critical coupled-mode flutter flow velocity are obtained, and the variations between the real part and imaginary part of dimensionless complex frequency and fluid velocity, mass ratio and the power law exponent (or graded index, volume fraction) for FGM pipe conveying fluid are analyzed.

  1. Fast CSF MRI for brain segmentation; Cross-validation by comparison with 3D T1-based brain segmentation methods

    DEFF Research Database (Denmark)

    van der Kleij, Lisa A.; de Bresser, Jeroen; Hendrikse, Jeroen

    2018-01-01

    ObjectiveIn previous work we have developed a fast sequence that focusses on cerebrospinal fluid (CSF) based on the long T-2 of CSF. By processing the data obtained with this CSF MRI sequence, brain parenchymal volume (BPV) and intracranial volume (ICV) can be automatically obtained. The aim...... of this study was to assess the precision of the BPV and ICV measurements of the CSF MRI sequence and to validate the CSF MRI sequence by comparison with 3D T-1-based brain segmentation methods.Materials and methodsTen healthy volunteers (2 females; median age 28 years) were scanned (3T MRI) twice......cc) and CSF HR (5 +/- 5/4 +/- 2cc) were comparable to FSL HR (9 +/- 11/19 +/- 23cc), FSL LR (7 +/- 4,6 +/- 5cc),FreeSurfer HR (5 +/- 3/14 +/- 8cc), FreeSurfer LR (9 +/- 8,12 +/- 10cc), and SPM HR (5 +/- 3/4 +/- 7cc), and SPM LR (5 +/- 4,5 +/- 3cc). The correlation between the measured volumes...

  2. A multi-atlas based method for automated anatomical rat brain MRI segmentation and extraction of PET activity.

    Science.gov (United States)

    Lancelot, Sophie; Roche, Roxane; Slimen, Afifa; Bouillot, Caroline; Levigoureux, Elise; Langlois, Jean-Baptiste; Zimmer, Luc; Costes, Nicolas

    2014-01-01

    Preclinical in vivo imaging requires precise and reproducible delineation of brain structures. Manual segmentation is time consuming and operator dependent. Automated segmentation as usually performed via single atlas registration fails to account for anatomo-physiological variability. We present, evaluate, and make available a multi-atlas approach for automatically segmenting rat brain MRI and extracting PET activies. High-resolution 7T 2DT2 MR images of 12 Sprague-Dawley rat brains were manually segmented into 27-VOI label volumes using detailed protocols. Automated methods were developed with 7/12 atlas datasets, i.e. the MRIs and their associated label volumes. MRIs were registered to a common space, where an MRI template and a maximum probability atlas were created. Three automated methods were tested: 1/registering individual MRIs to the template, and using a single atlas (SA), 2/using the maximum probability atlas (MP), and 3/registering the MRIs from the multi-atlas dataset to an individual MRI, propagating the label volumes and fusing them in individual MRI space (propagation & fusion, PF). Evaluation was performed on the five remaining rats which additionally underwent [18F]FDG PET. Automated and manual segmentations were compared for morphometric performance (assessed by comparing volume bias and Dice overlap index) and functional performance (evaluated by comparing extracted PET measures). Only the SA method showed volume bias. Dice indices were significantly different between methods (PF>MP>SA). PET regional measures were more accurate with multi-atlas methods than with SA method. Multi-atlas methods outperform SA for automated anatomical brain segmentation and PET measure's extraction. They perform comparably to manual segmentation for FDG-PET quantification. Multi-atlas methods are suitable for rapid reproducible VOI analyses.

  3. Comparison of methods for detecting nondeterministic BOLD fluctuation in fMRI.

    Science.gov (United States)

    Kiviniemi, Vesa; Kantola, Juha-Heikki; Jauhiainen, Jukka; Tervonen, Osmo

    2004-02-01

    Functional MR imaging (fMRI) has been used in detecting neuronal activation and intrinsic blood flow fluctuations in the brain cortex. This article is aimed for comparing the methods for analyzing the nondeterministic flow fluctuations. Fast Fourier Transformation (FFT), cross correlation (CC), spatial principal component analysis (sPCA), and independent component analysis (sICA) were compared. 15 subjects were imaged at 1.5 T. Three quantitative measures were compared: (1) The number of subjects with identifiable fluctuation, (2) the volume, and (3) mean correlation coefficient (MCC) of the detected voxels. The focusing on cortical structures and the overall usability were qualitatively assessed. sICA was spatially most accurate but time consuming, robust, and detected voxels with high temporal synchrony. The CC and FFT were fast suiting primary screening. The CC detected highest temporal synchrony but the subjective detection for reference vector produced excess variance of the detected volumes. The FFT and sPCA were not spatially accurate and did not detect adequate temporal synchrony of the voxels.

  4. Imaging transplanted stem cells in real time using an MRI dual-contrast method

    Science.gov (United States)

    Ngen, Ethel J.; Wang, Lee; Kato, Yoshinori; Krishnamachary, Balaji; Zhu, Wenlian; Gandhi, Nishant; Smith, Barbara; Armour, Michael; Wong, John; Gabrielson, Kathleen; Artemov, Dmitri

    2015-01-01

    Stem cell therapies are currently being investigated for the repair of brain injuries. Although exogenous stem cell labelling with superparamagnetic iron oxide nanoparticles (SPIONs) prior to transplantation provides a means to noninvasively monitor stem cell transplantation by magnetic resonance imaging (MRI), monitoring cell death is still a challenge. Here, we investigate the feasibility of using an MRI dual-contrast technique to detect cell delivery, cell migration and cell death after stem cell transplantation. Human mesenchymal stem cells were dual labelled with SPIONs and gadolinium-based chelates (GdDTPA). The viability, proliferation rate, and differentiation potential of the labelled cells were then evaluated. The feasibility of this MRI technique to distinguish between live and dead cells was next evaluated using MRI phantoms, and in vivo using both immune-competent and immune-deficient mice, following the induction of brain injury in the mice. All results were validated with bioluminescence imaging. In live cells, a negative (T2/T2*) MRI contrast predominates, and is used to track cell delivery and cell migration. Upon cell death, a diffused positive (T1) MRI contrast is generated in the vicinity of the dead cells, and serves as an imaging marker for cell death. Ultimately, this technique could be used to manage stem cell therapies. PMID:26330231

  5. Predicting response before initiation of neoadjuvant chemotherapy in breast cancer using new methods for the analysis of dynamic contrast enhanced MRI (DCE MRI) data

    Science.gov (United States)

    DeGrandchamp, Joseph B.; Whisenant, Jennifer G.; Arlinghaus, Lori R.; Abramson, V. G.; Yankeelov, Thomas E.; Cárdenas-Rodríguez, Julio

    2016-03-01

    The pharmacokinetic parameters derived from dynamic contrast enhanced (DCE) MRI have shown promise as biomarkers for tumor response to therapy. However, standard methods of analyzing DCE MRI data (Tofts model) require high temporal resolution, high signal-to-noise ratio (SNR), and the Arterial Input Function (AIF). Such models produce reliable biomarkers of response only when a therapy has a large effect on the parameters. We recently reported a method that solves the limitations, the Linear Reference Region Model (LRRM). Similar to other reference region models, the LRRM needs no AIF. Additionally, the LRRM is more accurate and precise than standard methods at low SNR and slow temporal resolution, suggesting LRRM-derived biomarkers could be better predictors. Here, the LRRM, Non-linear Reference Region Model (NRRM), Linear Tofts model (LTM), and Non-linear Tofts Model (NLTM) were used to estimate the RKtrans between muscle and tumor (or the Ktrans for Tofts) and the tumor kep,TOI for 39 breast cancer patients who received neoadjuvant chemotherapy (NAC). These parameters and the receptor statuses of each patient were used to construct cross-validated predictive models to classify patients as complete pathological responders (pCR) or non-complete pathological responders (non-pCR) to NAC. Model performance was evaluated using area under the ROC curve (AUC). The AUC for receptor status alone was 0.62, while the best performance using predictors from the LRRM, NRRM, LTM, and NLTM were AUCs of 0.79, 0.55, 0.60, and 0.59 respectively. This suggests that the LRRM can be used to predict response to NAC in breast cancer.

  6. Fast CSF MRI for brain segmentation; Cross-validation by comparison with 3D T1-based brain segmentation methods.

    Science.gov (United States)

    van der Kleij, Lisa A; de Bresser, Jeroen; Hendrikse, Jeroen; Siero, Jeroen C W; Petersen, Esben T; De Vis, Jill B

    2018-01-01

    In previous work we have developed a fast sequence that focusses on cerebrospinal fluid (CSF) based on the long T2 of CSF. By processing the data obtained with this CSF MRI sequence, brain parenchymal volume (BPV) and intracranial volume (ICV) can be automatically obtained. The aim of this study was to assess the precision of the BPV and ICV measurements of the CSF MRI sequence and to validate the CSF MRI sequence by comparison with 3D T1-based brain segmentation methods. Ten healthy volunteers (2 females; median age 28 years) were scanned (3T MRI) twice with repositioning in between. The scan protocol consisted of a low resolution (LR) CSF sequence (0:57min), a high resolution (HR) CSF sequence (3:21min) and a 3D T1-weighted sequence (6:47min). Data of the HR 3D-T1-weighted images were downsampled to obtain LR T1-weighted images (reconstructed imaging time: 1:59 min). Data of the CSF MRI sequences was automatically segmented using in-house software. The 3D T1-weighted images were segmented using FSL (5.0), SPM12 and FreeSurfer (5.3.0). The mean absolute differences for BPV and ICV between the first and second scan for CSF LR (BPV/ICV: 12±9/7±4cc) and CSF HR (5±5/4±2cc) were comparable to FSL HR (9±11/19±23cc), FSL LR (7±4, 6±5cc), FreeSurfer HR (5±3/14±8cc), FreeSurfer LR (9±8, 12±10cc), and SPM HR (5±3/4±7cc), and SPM LR (5±4, 5±3cc). The correlation between the measured volumes of the CSF sequences and that measured by FSL, FreeSurfer and SPM HR and LR was very good (all Pearson's correlation coefficients >0.83, R2 .67-.97). The results from the downsampled data and the high-resolution data were similar. Both CSF MRI sequences have a precision comparable to, and a very good correlation with established 3D T1-based automated segmentations methods for the segmentation of BPV and ICV. However, the short imaging time of the fast CSF MRI sequence is superior to the 3D T1 sequence on which segmentation with established methods is performed.

  7. A general method for selection of riboflavin-overproducing food grade micro-organisms

    Directory of Open Access Journals (Sweden)

    Rutten Ger

    2006-07-01

    Full Text Available Abstract Background This study describes a strategy to select and isolate spontaneous riboflavin-overproducing strains of Lactobacillus (Lb. plantarum, Leuconostoc (Lc. mesenteroides and Propionibacterium (P. freudenreichii. Results The toxic riboflavin analogue roseoflavin was used to isolate natural riboflavin-overproducing variants of the food grade micro-organisms Lb. plantarum, Lc. mesenteroides and P. freudenreichii strains. The method was successfully employed for strains of all three species. The mutation(s responsible for the observed overproduction of riboflavin were identified for isolates of two species. Conclusion Selection for spontaneous roseoflavin-resistant mutants was found to be a reliable method to obtain natural riboflavin-overproducing strains of a number of species commonly used in the food industry. This study presents a convenient method for deriving riboflavin-overproducing strains of bacterial starter cultures, which are currently used in the food industry, by a non-recombinant methodology. Use of such starter strains can be exploited to increase the vitamin content in certain food products.

  8. Study of Application for Excursion Observation Method in Primary School 2nd Grade Social Studies

    Directory of Open Access Journals (Sweden)

    Ahmet Ali GAZEL

    2014-04-01

    Full Text Available This study aims to investigate how field trips are conducted at 2nd grade of primary schools as a part of social studies course. Data for this research is compiled from 143 permanent Social Studies teachers working throughout 2011–2012 Education Year in the primary schools of central Kütahya and its districts. Data is compiled by using descriptive search model. In the research, after taking expert opinions, a measuring tool developed by the researcher is used. Data obtained from the research were transferred to computer, and analyses were made. In the analysis of the data, frequency and percentage values have been used to determine the distribution. Also a single factor variance analysis and t-test for independent samples have been used to determine the significance of difference between the variables. As a result of the research, it has been realized that insufficient importance is given to field trip method in Social Studies lessons. Most of the teachers using this method apply it in spring months. Teachers usually make use of field trips independent from unit/topic to increase the students’ motivation, and they generally use verbal expression in the class after tours. The biggest difficulty teachers encounter while using tour-observation method is the students’ undisciplined behavior.

  9. Interventional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Junta; Dohi, Michiko; Yoshihiro, Akiko; Mogami, Takuji; Kuwada, Tomoko; Nakata, Norio [Jikei Univ., Chiba (Japan). Kashiwa Hospital

    2000-06-01

    Open type MR system and fast sequence is now available and MRI becomes a new modality for interventional Radiology, including biopsy, drainage operation, and monitoring for minimally invasive therapy. Experimental studies of temperature monitoring were performed under hot and cold status. Signal changes of porcine disc and meat under microwave and laser ablation were observed as low signal area by signal intensity method. Using proton chemical shift method, signal change by laser ablation was displaced color imaging and correlated with thermometric temperature measurement. The very T2 relaxation time of ice affords excellent contrast between ice and surrounding gelatin tissue allowing acute depiction of the extent of the iceball under MRI. (author)

  10. Graph cut-based method for segmenting the left ventricle from MRI or echocardiographic images.

    Science.gov (United States)

    Bernier, Michael; Jodoin, Pierre-Marc; Humbert, Olivier; Lalande, Alain

    2017-06-01

    In this paper, we present a fast and interactive graph cut method for 3D segmentation of the endocardial wall of the left ventricle (LV) adapted to work on two of the most widely used modalities: magnetic resonance imaging (MRI) and echocardiography. Our method accounts for the fundamentally different nature of both modalities: 3D echocardiographic images have a low contrast, a poor signal-to-noise ratio and frequent signal drop, while MR images are more detailed but also cluttered and contain highly anisotropic voxels. The main characteristic of our method is to work in a 3D Bezier coordinate system instead of the original Euclidean space. This comes with several advantages, including an implicit shape prior and a result guarantied not to have any holes in it. The proposed method is made of 4 steps. First, a 3D sampling of the LV cavity is made based on a Bezier coordinate system. This allows to warp the input 3D image to a Bezier space in which a plane corresponds to an anatomically plausible 3D Euclidean bullet shape. Second, a 3D graph is built and an energy term (which is based on the image gradient and a 3D probability map) is assigned to each edge of the graph, some of which being given an infinite energy to ensure the resulting 3D structure passes through key anatomical points. Third, a max-flow min-cut procedure is executed on the energy graph to delineate the endocardial surface. And fourth, the resulting surface is projected back to the Euclidean space where a post-processing convex hull algorithm is applied on every short axis slice to remove local concavities. Results obtained on two datasets reveal that our method takes between 2 and 5s to segment a 3D volume, it has better results overall than most state-of-the-art methods on the CETUS echocardiographic dataset and is statistically as good as a human operator on MR images. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A new operational method of functional neurosurgery combining micro-recording and MRI stereotaxy for the treatment of Parkinson's disease

    International Nuclear Information System (INIS)

    Nishimura, Hiroyuki; Hirai, Tatsuo.

    1993-01-01

    We have developed a new operational method for stereotactic functional neurosurgery using MRI stereotaxy combined with microelectrode recording. MRI stereotaxy shows us the individual variations of thalamic configurations. The tentative target points were determined using the MRI stereotaxy assisted software system which revised the distortion of MRI images. Consequently, the accuracy and safety of the microelectrode recording were increased. This, in turn, increased the accuracy and stereotactic thalamotomy while producing encouraging operational outcomes. The effectiveness of stereotactic thalamotomy for Parkinson's disease was confirmed by these excellent operative results. The symptoms improved and the dosage of medications, including L-DOPA, decreased. Furthermore, our results indicate that the distributing area of deep sensory neurons in the thalamus extended more posteriorly and upward than previously expected. Therefore, the functional and anatomical similarity between the human and monkey thalamus was reaffirmed. In this report, based on the above data, we reevaluated the neural mechanism of tremor and the role of stereotactic functional neurosurgery for Parkinson's disease. (author)

  12. A new operational method of functional neurosurgery combining micro-recording and MRI stereotaxy for the treatment of Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Hiroyuki [Kochi Medical School, Nankoku (Japan); Hirai, Tatsuo

    1993-02-01

    We have developed a new operational method for stereotactic functional neurosurgery using MRI stereotaxy combined with microelectrode recording. MRI stereotaxy shows us the individual variations of thalamic configurations. The tentative target points were determined using the MRI stereotaxy assisted software system which revised the distortion of MRI images. Consequently, the accuracy and safety of the microelectrode recording were increased. This, in turn, increased the accuracy and stereotactic thalamotomy while producing encouraging operational outcomes. The effectiveness of stereotactic thalamotomy for Parkinson's disease was confirmed by these excellent operative results. The symptoms improved and the dosage of medications, including L-DOPA, decreased. Furthermore, our results indicate that the distributing area of deep sensory neurons in the thalamus extended more posteriorly and upward than previously expected. Therefore, the functional and anatomical similarity between the human and monkey thalamus was reaffirmed. In this report, based on the above data, we reevaluated the neural mechanism of tremor and the role of stereotactic functional neurosurgery for Parkinson's disease. (author).

  13. Novel methods and applications of NMR and MRI. Low-power RF excitation and hyperpolarized Xenon-129

    International Nuclear Information System (INIS)

    Amor, Nadia

    2012-01-01

    Since their discovery in the middle of the last century, Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) have become an important and very versatile tool in industry, medicine, and basic research. The aim of this work is to explore possible improvements and new applications of NMR methods. First, a recently introduced excitation NMR pulse sequence, termed Frank sequence excitation, which allows for significant reduction of rf-excitation power, is systematically analyzed and compared to conventional NMR in detail. Furthermore, its feasibility for MRI is investigated and advantages as well as drawbacks in comparison to standard MRI are discussed. The second part focuses on new biomedical applications of hyperpolarized (HP) 129 Xe which not only offers a signal enhancement of several orders of magnitude but also provides new contrast mechanisms. A setup for continuous dissolution of HP 129 Xe gas into blood and other fluids is optimized and analyzed quantitatively by NMR and MRI. On the basis of these results, blood-dissolved HP 129 Xe is used to investigate blood-gas dynamics, as well as the rheological behavior of blood.

  14. Novel methods and applications of NMR and MRI. Low-power RF excitation and hyperpolarized Xenon-129

    Energy Technology Data Exchange (ETDEWEB)

    Amor, Nadia

    2012-07-01

    Since their discovery in the middle of the last century, Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) have become an important and very versatile tool in industry, medicine, and basic research. The aim of this work is to explore possible improvements and new applications of NMR methods. First, a recently introduced excitation NMR pulse sequence, termed Frank sequence excitation, which allows for significant reduction of rf-excitation power, is systematically analyzed and compared to conventional NMR in detail. Furthermore, its feasibility for MRI is investigated and advantages as well as drawbacks in comparison to standard MRI are discussed. The second part focuses on new biomedical applications of hyperpolarized (HP) {sup 129}Xe which not only offers a signal enhancement of several orders of magnitude but also provides new contrast mechanisms. A setup for continuous dissolution of HP {sup 129}Xe gas into blood and other fluids is optimized and analyzed quantitatively by NMR and MRI. On the basis of these results, blood-dissolved HP {sup 129}Xe is used to investigate blood-gas dynamics, as well as the rheological behavior of blood.

  15. The Effect of Using Cooperative Learning Method on Tenth Grade Students' Learning Achievement and Attitude towards Biology

    Science.gov (United States)

    Rabgay, Tshewang

    2018-01-01

    The study investigated the effect of using cooperative learning method on tenth grade students' learning achievement in biology and their attitude towards the subject in a Higher Secondary School in Bhutan. The study used a mixed method approach. The quantitative component included an experimental design where cooperative learning was the…

  16. Aspects That Arise in the Transition from the Montessori Method to a Traditional Method: A Fourth Grade Mathematics View

    Science.gov (United States)

    Hurdle, Zachariah B.

    2017-01-01

    The purpose of the dissertation is to investigate three particular aspects that may affect the transition between a third grade Montessori system and a fourth grade non-Montessori system, specifically within the context of teaching and learning mathematics. These aspects are 1) the change in pacing and structure of the classroom, 2) the removal of…

  17. MRI: A method to detect minor brain damage following coronary bypass surgery

    Energy Technology Data Exchange (ETDEWEB)

    Vik, A.; Brubakk, A.O. (Trondheim Univ. (Norway). Dept. of Biomedical Engineering); Rinck, P.A. (Trondheim Univ. (Norway). MR Center); Sande, E.; Levang, O.W. (Trondheim Univ. Hospital (Norway). Dept. of Surgery); Sellevold, O. (Trondheim Univ. Hospital (Norway). Dept. of Anaesthesiology)

    1991-10-01

    In order to assess the occurrence of minor focal brain lesions after coronary bypass surgery, magnetic resonance imaging (MRI) was used. Nine male patients (age 42-63) with angina pectoris were investigated at 0.5 Tesla. The investigation was performed one to seven weeks prior to the operation and one month after the operation. Before surgery, the images demonstrated more than five high intensity spots in the white matter of the brain in all but two patients. No additional spots were found after operation. This pilot study indicates that it might be difficult to use MRI to detect minor parenchymal lesions after cardiopulmonary bypass surgery. (orig.).

  18. Initial evaluation of a practical PET respiratory motion correction method in clinical simultaneous PET/MRI

    International Nuclear Information System (INIS)

    Manber, Richard; Thielemans, Kris; Hutton, Brian; Barnes, Anna; Ourselin, Sebastien; Arridge, Simon; O’Meara, Celia; Atkinson, David

    2014-01-01

    Respiratory motion during PET acquisitions can cause image artefacts, with sharpness and tracer quantification adversely affected due to count ‘smearing’. Motion correction by registration of PET gates becomes increasingly difficult with shorter scan times and less counts. The advent of simultaneous PET/MRI scanners allows the use of high spatial resolution MRI to capture motion states during respiration [1, 2]. In this work, we use a respiratory signal derived from the PET list-mode data [3, ], with no requirement for an external device or MR sequence modifications.

  19. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 μg/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 μg. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

  20. Image fusion of MRI and fMRI with intraoperative MRI data: methods and clinical relevance for neurosurgical interventions; Fusion von MRT-, fMRT- und intraoperativen MRT-Daten. Methode und klinische Bedeutung am Beispiel neurochirurgischer Interventionen

    Energy Technology Data Exchange (ETDEWEB)

    Moche, M.; Busse, H.; Dannenberg, C.; Schulz, T.; Schmidt, F.; Kahn, T. [Universitaetsklinikum Leipzig (Germany). Klinik und Poliklinik fuer Diagnostische Radiologie; Schmitgen, A. [GMD Forschungszentrum Informationstechnik GmbH-FIT, Sankt Augustin (Germany); Trantakis, C.; Winkler, D. [Klinik und Poliklinik fuer Neurochirurgie, Universitaetsklinikum Leipzig (Germany)

    2001-11-01

    The aim of this work was to realize and clinically evaluate an image fusion platform for the integration of preoperative MRI and fMRI data into the intraoperative images of an interventional MRI system with a focus on neurosurgical procedures. A vertically open 0.5 T MRI scanner was equipped with a dedicated navigation system enabling the registration of additional imaging modalities (MRI, fMRI, CT) with the intraoperatively acquired data sets. These merged image data served as the basis for interventional planning and multimodal navigation. So far, the system has been used in 70 neurosurgical interventions (13 of which involved image data fusion - requiring 15 minutes extra time). The augmented navigation system is characterized by a higher frame rate and a higher image quality as compared to the system-integrated navigation based on continuously acquired (near) real time images. Patient movement and tissue shifts can be immediately detected by monitoring the morphological differences between both navigation scenes. The multimodal image fusion allowed a refined navigation planning especially for the resection of deeply seated brain lesions or pathologies close to eloquent areas. Augmented intraoperative orientation and instrument guidance improve the safety and accuracy of neurosurgical interventions. (orig.) [German] Ziel dieser Arbeit waren die Realisierung und klinische Bewertung einer Bildfusion praeoperativer MRT- und fMRT-Bilder mit intraoperativen Datensaetzen eines interventionellen MRT-Systems am Beispiel neurochirurgischer Eingriffe. Ein vertikal offenes 0,5-T-MRT-System wurde mit einem erweiterten Navigationssystem ausgestattet, welches eine Integration zusaetzlicher Bildinformationen (Hochfeld-MRT, fMRT, CT) in die intraoperativ akquirierten Datensaetze erlaubt. Diese fusionierten Bilddaten wurden zur Interventionsplanung und multimodalen Navigation verwendet. Bisher wurde das System bei insgesamt 70 neurochirurgischen Eingriffen eingesetzt, davon 13

  1. Teaching Dental Students to Understand the Temporomandibular Joint Using MRI: Comparison of Conventional and Digital Learning Methods.

    Science.gov (United States)

    Arús, Nádia A; da Silva, Átila M; Duarte, Rogério; da Silveira, Priscila F; Vizzotto, Mariana B; da Silveira, Heraldo L D; da Silveira, Heloisa E D

    2017-06-01

    The aims of this study were to evaluate and compare the performance of dental students in interpreting the temporomandibular joint (TMJ) with magnetic resonance imaging (MRI) scans using two learning methods (conventional and digital interactive learning) and to examine the usability of the digital learning object (DLO). The DLO consisted of tutorials about MRI and anatomic and functional aspects of the TMJ. In 2014, dental students in their final year of study who were enrolled in the elective "MRI Interpretation of the TMJ" course comprised the study sample. After exclusions for nonattendance and other reasons, 29 of the initial 37 students participated in the study, for a participation rate of 78%. The participants were divided into two groups: a digital interactive learning group (n=14) and a conventional learning group (n=15). Both methods were assessed by an objective test applied before and after training and classes. Aspects such as support and training requirements, complexity, and consistency of the DLO were also evaluated using the System Usability Scale (SUS). A significant between-group difference in the posttest results was found, with the conventional learning group scoring better than the DLO group, indicated by mean scores of 9.20 and 8.11, respectively, out of 10. However, when the pretest and posttest results were compared, both groups showed significantly improved performance. The SUS score was 89, which represented a high acceptance of the DLO by the users. The students who used the conventional method of learning showed superior performance in interpreting the TMJ using MRI compared to the group that used digital interactive learning.

  2. Free vibration of functionally graded beams and frameworks using the dynamic stiffness method

    Science.gov (United States)

    Banerjee, J. R.; Ananthapuvirajah, A.

    2018-05-01

    The free vibration analysis of functionally graded beams (FGBs) and frameworks containing FGBs is carried out by applying the dynamic stiffness method and deriving the elements of the dynamic stiffness matrix in explicit algebraic form. The usually adopted rule that the material properties of the FGB vary continuously through the thickness according to a power law forms the fundamental basis of the governing differential equations of motion in free vibration. The differential equations are solved in closed analytical form when the free vibratory motion is harmonic. The dynamic stiffness matrix is then formulated by relating the amplitudes of forces to those of the displacements at the two ends of the beam. Next, the explicit algebraic expressions for the dynamic stiffness elements are derived with the help of symbolic computation. Finally the Wittrick-Williams algorithm is applied as solution technique to solve the free vibration problems of FGBs with uniform cross-section, stepped FGBs and frameworks consisting of FGBs. Some numerical results are validated against published results, but in the absence of published results for frameworks containing FGBs, consistency checks on the reliability of results are performed. The paper closes with discussion of results and conclusions.

  3. A Novel Method to Generate and Expand Clinical-Grade, Genetically Modified, Tumor-Infiltrating Lymphocytes

    Directory of Open Access Journals (Sweden)

    Marie-Andrée Forget

    2017-08-01

    Full Text Available Following the clinical success achieved with the first generation of adoptive cell therapy (ACT utilizing in vitro expanded tumor-infiltrating lymphocytes (TILs, the second and third generations of TIL ACT are evolving toward the use of genetically modified TIL. TIL therapy generally involves the transfer of a high number of TIL, ranging from 109 to 1011 cells. One of the technical difficulties in genetically modifying TIL, using a retroviral vector, is the ability to achieve large expansion of transduced TIL, while keeping the technique suitable to a Good Manufacturing Practices (GMP environment. Consequently, we developed and optimized a novel method for the efficient production of large numbers of GMP-grade, gene-modified TIL for the treatment of patients with ACT. The chemokine receptor CXCR2 was used as the gene of interest for methodology development. The optimized procedure is currently used in the production of gene-modified TIL for two clinical trials for the treatment of metastatic melanoma at MD Anderson Cancer Center.

  4. A prospective randomized comparison between two MRI studies of the small bowel in Crohn's disease, the oral contrast method and MR enteroclysis

    International Nuclear Information System (INIS)

    Negaard, Anne; Paulsen, Vemund; Lygren, Idar; Sandvik, Leiv; Berstad, Audun E.; Borthne, Arne; Try, Kirsti; Storaas, Tryggve; Klow, Nils-Einar

    2007-01-01

    The aim was to compare bowel distension and diagnostic properties of magnetic resonance imaging of the small bowel with oral contrast (MRI per OS) with magnetic resonance enteroclysis (MRE). Forty patients with suspected Crohn's disease (CD) were examined with both MRI methods. MRI per OS was performed with a 6% mannitol solution and MRE with nasojejunal intubation and a polyethylenglycol solution. MRI protocol consisted of balanced fast field echo (B-FFE), T2 and T1 sequences with and without gadolinium. Two experienced radiologists individually evaluated bowel distension and pathological findings including wall thickness (BWT), contrast enhancement (BWE), ulcer (BWU), stenosis (BWS) and edema (EDM). The diameter of the small bowel was smaller with MRI per OS than with MRE (difference jejunum: 0.55 cm, p < 0.001; ileum: 0.35 cm, p < 0.001, terminal ileum: 0.09 cm, p = 0.08). However, CD was diagnosed with high diagnostic accuracy (sensitivity, specificity, positive and negative predictive values: MRI per OS 88%, 89%, 89%, 89%; MRE 88%, 84%, 82%, 89%) and inter-observer agreement (MRI per OS k = 0.95; MRE k = 1). In conclusion, bowel distension was inferior in MRI per OS compared to MRE. However, both methods diagnosed CD with a high diagnostic accuracy and reproducibility. (orig.)

  5. A non-invasive method of quantifying pancreatic volume in mice using micro-MRI.

    Directory of Open Access Journals (Sweden)

    Jose L Paredes

    Full Text Available In experimental models of pancreatic growth and recovery, changes in pancreatic size are assessed by euthanizing a large cohort of animals at varying time points and measuring organ mass. However, to ascertain this information in clinical practice, patients with pancreatic disorders routinely undergo non-invasive cross-sectional imaging of the pancreas using magnetic resonance imaging (MRI or computed tomography (CT. The aim of the current study was to develop a thin-sliced, optimized sequence protocol using a high field MRI to accurately calculate pancreatic volumes in the most common experimental animal, the mouse. Using a 7 Telsa Bruker micro-MRI system, we performed abdominal imaging in whole-fixed mice in three standard planes: axial, sagittal, and coronal. The contour of the pancreas was traced using Vitrea software and then transformed into a 3-dimensional (3D reconstruction, from which volumetric measurements were calculated. Images were optimized using heart perfusion-fixation, T1 sequence analysis, and 0.2 to 0.4 mm thick slices. As proof of principle, increases in pancreatic volume among mice of different ages correlated tightly with increasing body weight. In summary, this is the first study to measure pancreatic volumes in mice, using a high field 7 Tesla micro-MRI and a thin-sliced, optimized sequence protocol. We anticipate that micro-MRI will improve the ability to non-invasively quantify changes in pancreatic size and will dramatically reduce the number of animals required to serially assess pancreatic growth and recovery.

  6. Quantitative chemical shift-encoded MRI is an accurate method to quantify hepatic steatosis.

    Science.gov (United States)

    Kühn, Jens-Peter; Hernando, Diego; Mensel, Birger; Krüger, Paul C; Ittermann, Till; Mayerle, Julia; Hosten, Norbert; Reeder, Scott B

    2014-06-01

    To compare the accuracy of liver fat quantification using a three-echo chemical shift-encoded magnetic resonance imaging (MRI) technique without and with correction for confounders with spectroscopy (MRS) as the reference standard. Fifty patients (23 women, mean age 56.6 ± 13.2 years) with fatty liver disease were enrolled. Patients underwent T2-corrected single-voxel MRS and a three-echo chemical shift-encoded gradient echo (GRE) sequence at 3.0T. MRI fat fraction (FF) was calculated without and with T2* and T1 correction and multispectral modeling of fat and compared with MRS-FF using linear regression. The spectroscopic range of liver fat was 0.11%-38.7%. Excellent correlation between MRS-FF and MRI-FF was observed when using T2* correction (R(2)  = 0.96). With use of T2* correction alone, the slope was significantly different from 1 (1.16 ± 0.03, P fat were addressed, the results showed equivalence between fat quantification using MRI and MRS (slope: 1.02 ± 0.03, P = 0.528; intercept: 0.26% ± 0.46%, P = 0.572). Complex three-echo chemical shift-encoded MRI is equivalent to MRS for quantifying liver fat, but only with correction for T2* decay and T1 recovery and use of spectral modeling of fat. This is necessary because T2* decay, T1 recovery, and multispectral complexity of fat are processes which may otherwise bias the measurements. Copyright © 2013 Wiley Periodicals, Inc.

  7. Reflecting on an impact evaluation of the Grade R programme: Method, results and policy responses

    Directory of Open Access Journals (Sweden)

    Marie-Louise Samuels

    2015-08-01

    Full Text Available This paper describes the expansion since 2001 of a public pre-school programme in South Africa known as ‘Grade R’, summarises the findings from an impact evaluation of the introduction of Grade R, discusses the policy recommendations flowing from the evaluation and reflects on the process of implementing the recommendations. The Grade R programme has expanded dramatically, to the point where participation is nearly universal. Although a substantial literature points to large potential benefits from pre-school educational opportunities, the impact evaluation reported on in this article demonstrated that the Grade R programme, as implemented until 2011, had a limited impact on later educational outcomes. Improving the quality of Grade R, especially in schools serving low socio-economic status communities, thus emerges as a key policy imperative. Recommended responses include professionalising Grade R teachers, providing practical in-service support, increasing access to appropriate storybooks, empowering teachers to assess the development of their learners, and improving financial record-keeping of Grade R expenditure by provincial education departments. The impact evaluation was initiated by the Department of Planning, Monitoring and Evaluation (DPME and the Department of Basic Education (DBE, and was conducted by independent researchers. The move towards increased evaluation of key government programmes is important for shifting the focus of programme managers and policymakers towards programme outcomes rather than only programme inputs. Yet the process is not without its challenges: following a clear process to ensure the implementation of the lessons learned from such an evaluation is not necessarily straightforward.

  8. SU-D-207A-06: Pediatric Abdominal Organ Motion Quantified Via a Novel 4D MRI Method

    Energy Technology Data Exchange (ETDEWEB)

    Uh, J; Krasin, MJ; Lucas, JT; Tinkle, C; Merchant, TE; Hua, C [St. Jude Children’s Research Hospital, Memphis, TN (United States)

    2016-06-15

    Purpose: To develop a 4D MRI method for assessing respiration-induced abdominal organ motion in children receiving radiation therapy. Methods: A 4D MRI using internal image-based respiratory surrogate has been developed and implemented on a clinical scanner (1.5T Siemens Avanto). Ten patients (younger group: N=6, 2–5 years, anesthetized; older group: N=4, 11–15 years) with neuroblastoma, Wilm’s tumor rhabdomyosarcoma, or desmoplastic small round cell tumor received free breathing 4D MRI scans for treatment planning. Coronal image slices of the entire abdomen were retrospectively constructed in 10 respiratory phases. A B-spline deformable registration (Metz et al. 2011) was performed on 4D datasets to automatically derive motion trajectories of selected anatomical landmarks, including the dome and the center of the liver, and the superior edges of kidneys and spleen. The extents of the motion in three dimensions (anteroposterior, AP; mediolateral, ML; superoinferior, SI) and the correlations between organ motion trajectories were quantified. Results: The 4D MRI scans were successfully performed in <20 minutes for all patients without the use of any external device. Organ motion extents were larger in adolescents (kidneys: 3–13 mm SI, liver and spleen: 6–18 mm SI) than in younger children (kidneys:<3mm in all directions; liver and spleen: 1–8 mm SI, 1–5 mm ML and AP). The magnitude of respiratory motion in some adolescents may warrant special motion management. Motion trajectories were not synchronized across selected anatomical landmarks, particularly in the ML and AP directions, indicating inter- and intra-organ variations of the respiratory-induced motion. Conclusion: The developed 4D MRI acquisition and motion analysis methods provide a non-ionizing, non-invasive approach to automatically measure the organ motion trajectory in the pediatric abdomen. It is useful for defining ITV and PRV, monitoring changes in target motion patterns during the

  9. Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers by differential quadrature method

    Energy Technology Data Exchange (ETDEWEB)

    Alashti, R. Akbari, E-mail: raalashti@nit.ac.ir [Mechanical Engineering Department, Babol University of Technology, P.O. Box 484, Shariati Avenue, Babol (Iran, Islamic Republic of); Khorsand, M. [Mechanical Engineering Department, Babol University of Technology, P.O. Box 484, Shariati Avenue, Babol (Iran, Islamic Republic of)

    2011-05-15

    Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers under the effect of asymmetric thermo-electro-mechanical loads is carried out. Numerical results of displacement, stress and thermal fields are obtained using two versions of the differential quadrature methods, namely polynomial and Fourier quadrature methods. Material properties of the shell are assumed to be graded in the radial direction according to a power law but the Poisson's ratio is assumed to be constant. Shells are considered to be under the effect of the pressure loading in the form of cosine and ring pressure loads, electric potentials and temperature fields. Numerical results for various boundary conditions are obtained and the effects of the thickness of piezoelectric layers, grading index of material properties and the ratio of the thickness to the radius of the shell on these results is presented. - Highlights: > A numerical study of an FGM cylindrical shell with piezoelectric layers is made. > Governing equations are solved by two versions of differential quadrature methods. > The effect of layers thickness, grading index and geometrical ratios is presented.

  10. Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers by differential quadrature method

    International Nuclear Information System (INIS)

    Alashti, R. Akbari; Khorsand, M.

    2011-01-01

    Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers under the effect of asymmetric thermo-electro-mechanical loads is carried out. Numerical results of displacement, stress and thermal fields are obtained using two versions of the differential quadrature methods, namely polynomial and Fourier quadrature methods. Material properties of the shell are assumed to be graded in the radial direction according to a power law but the Poisson's ratio is assumed to be constant. Shells are considered to be under the effect of the pressure loading in the form of cosine and ring pressure loads, electric potentials and temperature fields. Numerical results for various boundary conditions are obtained and the effects of the thickness of piezoelectric layers, grading index of material properties and the ratio of the thickness to the radius of the shell on these results is presented. - Highlights: → A numerical study of an FGM cylindrical shell with piezoelectric layers is made. → Governing equations are solved by two versions of differential quadrature methods. → The effect of layers thickness, grading index and geometrical ratios is presented.

  11. High-grade and low-grade gliomas: differentiation by using perfusion MR imaging

    International Nuclear Information System (INIS)

    Hakyemez, B.; Erdogan, C.; Ercan, I.; Ergin, N.; Uysal, S.; Atahan, S.

    2005-01-01

    AIM: Relative cerebral blood volume (rCBV) is a commonly used perfusion magnetic resonance imaging (MRI) technique for the evaluation of tumour grade. Relative cerebral blood flow (rCBF) has been less studied. The goal of our study was to determine the usefulness of these parameters in evaluating the histopathological grade of the cerebral gliomas. METHODS: This study involved 33 patients (22 high-grade and 11 low-grade glioma cases). MRI was performed for all tumours by using a first-passage gadopentetate dimeglumine T2*-weighted gradient-echo single-shot echo-planar sequence followed by conventional MRI. The rCBV and rCBF were calculated by deconvolution of an arterial input function. The rCBV and rCBF ratios of the lesions were obtained by dividing the values obtained from the normal white matter of the contralateral hemisphere. For statistical analysis Mann-Whitney testing was carried out. A p value of less than 0.05 indicated a statistically significant difference. Receiver operating characteristic curve (ROC) analysis was performed to assess the relationship between the rCBV and rCBF ratios and grade of gliomas. Their cut-off value permitting discrimination was calculated. The correlation between rCBV and CBF ratios and glioma grade was assessed using Pearson correlation analysis. RESULTS: In high-grade gliomas, rCBV and rCBF ratios were measured as 6.50±4.29 and 3.32±1.87 (mean±SD), respectively. In low-grade gliomas, rCBV and rCBF ratios were 1.69±0.51 and 1.16±0.38, respectively. The rCBV and rCBF ratios for high-grade gliomas were statistically different from those of low-grade gliomas (p 0.05). The cut-off value was taken as 1.98 in the rCBV ratio and 1.25 in the rCBF ratio. There was a strong correlation between the rCBV and CBF ratios (Pearson correlation = 0.830, p<0.05). CONCLUSION: Perfusion MRI is useful in the preoperative assessment of the histopathologicalal grade of gliomas; the rCBF ratio in addition to the rCBV ratio can be incorporated

  12. Non-invasive tryptophan fluorescence measurements as a novel method of grading cataract

    DEFF Research Database (Denmark)

    Erichsen, Jesper Høiberg; Mensah, Aurore; Kessel, Line

    2017-01-01

    . All cataracts were age-related. Lens material from 16 eyes of 14 patients was included in the study. Cataracts were preoperatively graded in categories 1, 2 and 3. No lenses were category 4. For nuclear cataracts mean values of F-factor were 52.9 (SD 12.2), 61.7 (SD 5.3) and 75.7 (SD 8.9......) for categories 1, 2 and 3 respectively. Linear regression on F-factor as a function of preoperative grading category showed increasing values of F-factor with increasing preoperative grading category, R2 = 0.515. Our experiment showed that preoperative optical grading of cataracts by Scheimpflug imaging may......Development of non-invasive treatments for cataract calls for a sensitive diagnostic assay. We conducted a study to test whether the ratio of folded tryptophan to non-tryptophan fluorescence emission (F-factor) may be used for grading cataracts in human lenses. The F-factor was measured...

  13. Degenerative joint disease on MRI and physical activity: a clinical study of the knee joint in 320 patients

    International Nuclear Information System (INIS)

    Bachmann, G.F.; Rauber, K.; Damian, M.S.; Rau, W.S.; Basad, E.

    1999-01-01

    We examined 320 patients with MRI and arthroscopy after an acute trauma to evaluate MRI in diagnosis of degenerative joint disease of the knee in relation to sports activity and clinical data. Lesions of cartilage and menisci on MRI were registered by two radiologists in consensus without knowledge of arthroscopy. Arthroscopy demonstrated grade-1 to grade-4 lesions of cartilage on 729 of 1920 joint surfaces of 320 knees, and MRI diagnosed 14 % of grade-1, 32 % of grade-2, 94 % of grade-3, and 100 % of grade-4 lesions. Arthroscopy explored 1280 meniscal areas and showed degenerations in 10 %, tears in 11.4 %, and complex lesions in 9.2 %. Magnetic resonance imaging was in agreement with arthroscopy in 81 % showing more degenerations but less tears of menisci than arthroscopy. Using a global system for grading the total damage of the knee joint into none, mild, moderate, or severe changes, agreement between arthroscopy and MRI was found in 82 %. Magnetic resonance imaging and arthroscopy showed coherently that degree of degenerative joint changes was significantly correlated to patient age or previous knee trauma. Patients over 40 years had moderate to severe changes on MRI in 45 % and patients under 30 years in only 22 %. Knee joints with a history of trauma without complete structural or functional reconstitution showed marked changes on MRI in 57 %, whereas stable joints without such alterations had degenerative changes in only 26 %. There was no correlation of degenerative disease to gender, weight, type, frequency, and intensity of sports activity. Therefore, MRI is an effective non-invasive imaging method for exact localization and quantification of chronic joint changes of cartilage and menisci that recommends MRI for monitoring in sports medicine. (orig.) (orig.)

  14. Multi-method analysis of MRI images in early diagnostics of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Robin Wolz

    Full Text Available The role of structural brain magnetic resonance imaging (MRI is becoming more and more emphasized in the early diagnostics of Alzheimer's disease (AD. This study aimed to assess the improvement in classification accuracy that can be achieved by combining features from different structural MRI analysis techniques. Automatically estimated MR features used are hippocampal volume, tensor-based morphometry, cortical thickness and a novel technique based on manifold learning. Baseline MRIs acquired from all 834 subjects (231 healthy controls (HC, 238 stable mild cognitive impairment (S-MCI, 167 MCI to AD progressors (P-MCI, 198 AD from the Alzheimer's Disease Neuroimaging Initiative (ADNI database were used for evaluation. We compared the classification accuracy achieved with linear discriminant analysis (LDA and support vector machines (SVM. The best results achieved with individual features are 90% sensitivity and 84% specificity (HC/AD classification, 64%/66% (S-MCI/P-MCI and 82%/76% (HC/P-MCI with the LDA classifier. The combination of all features improved these results to 93% sensitivity and 85% specificity (HC/AD, 67%/69% (S-MCI/P-MCI and 86%/82% (HC/P-MCI. Compared with previously published results in the ADNI database using individual MR-based features, the presented results show that a comprehensive analysis of MRI images combining multiple features improves classification accuracy and predictive power in detecting early AD. The most stable and reliable classification was achieved when combining all available features.

  15. A new bias field correction method combining N3 and FCM for improved segmentation of breast density on MRI.

    Science.gov (United States)

    Lin, Muqing; Chan, Siwa; Chen, Jeon-Hor; Chang, Daniel; Nie, Ke; Chen, Shih-Ting; Lin, Cheng-Ju; Shih, Tzu-Ching; Nalcioglu, Orhan; Su, Min-Ying

    2011-01-01

    Quantitative breast density is known as a strong risk factor associated with the development of breast cancer. Measurement of breast density based on three-dimensional breast MRI may provide very useful information. One important step for quantitative analysis of breast density on MRI is the correction of field inhomogeneity to allow an accurate segmentation of the fibroglandular tissue (dense tissue). A new bias field correction method by combining the nonparametric nonuniformity normalization (N3) algorithm and fuzzy-C-means (FCM)-based inhomogeneity correction algorithm is developed in this work. The analysis is performed on non-fat-sat T1-weighted images acquired using a 1.5 T MRI scanner. A total of 60 breasts from 30 healthy volunteers was analyzed. N3 is known as a robust correction method, but it cannot correct a strong bias field on a large area. FCM-based algorithm can correct the bias field on a large area, but it may change the tissue contrast and affect the segmentation quality. The proposed algorithm applies N3 first, followed by FCM, and then the generated bias field is smoothed using Gaussian kernal and B-spline surface fitting to minimize the problem of mistakenly changed tissue contrast. The segmentation results based on the N3+FCM corrected images were compared to the N3 and FCM alone corrected images and another method, coherent local intensity clustering (CLIC), corrected images. The segmentation quality based on different correction methods were evaluated by a radiologist and ranked. The authors demonstrated that the iterative N3+FCM correction method brightens the signal intensity of fatty tissues and that separates the histogram peaks between the fibroglandular and fatty tissues to allow an accurate segmentation between them. In the first reading session, the radiologist found (N3+FCM > N3 > FCM) ranking in 17 breasts, (N3+FCM > N3 = FCM) ranking in 7 breasts, (N3+FCM = N3 > FCM) in 32 breasts, (N3+FCM = N3 = FCM) in 2 breasts, and (N3 > N3

  16. Evaluation of FSE and FSPGR MRI imaging methods for planning cranial stereotactic irradiation of a metastatic brain tumor

    International Nuclear Information System (INIS)

    Terada, Masaki; Tanoi, Chiharu

    2003-01-01

    Cranial stereotactic irradiation (STI) of a metastatic brain tumor (BT) was planned by fusing CT images with MRI images using the landmark method of the X-Knife System. The MRI images revealed the BT, the critical optic nerve and brain stem of structures and the eyeball and blood vessels that are landmarks. It was important to improve visibility of the BT with sufficient contrast. Therefore, comparison examinations were performed using the two dimensions fast spin echo (2DFSE), the two dimensions fast spoiled gradient echo (2DFSPGR), and the three dimensions fast spoiled gradient echo (3DFSPGR) methods of T1-weighted imaging with Gd-DTPA contrast. Critical structures and the internal structures of the landmark method were suitable for planning STI when the results of three or more points were combined in visual evaluations. However, the 2DFSE method could showed three or more points. The BT also be visually evaluated using three or less points by the FSPGR method, but had reduced visibility. From detailed contents, the fall of visual evaluation by the small thin and solid BT of the diameter of a BT was characteristic. In the whole signal noise ratio (SNR), the 3DFSPGR method is excellent in images analysis, and the 2DFSE method was excellent in contrast noise ratio (CNR) of a BT. The cystic BT accompanied by dropsy was images with clear and good depiction in all scan parameter. However, the FSPGR method was the boundary not clear in the small solid BT, the FSE method was able to recognize the maximum of the diameter of BT most, and depiction was good. Artifacts of blood flow and motion of the FSE method is a fault. However, the FSE method had the highest useful depiction ability of all BT in the STI plan. (author)

  17. Titrimetric determination of uranium in low-grade ores by the ferrous ion-phosphoric acid reduction method

    International Nuclear Information System (INIS)

    Hitchen, A.; Zechanowitsch, G.

    1980-01-01

    The modification and extension of the U.S.A.E.C. ferrous ion-phosphoric acid reduction method for the determination of uranium in high-grade or relatively pure material to a method for the determination of uranium with a high accuracy and precision, in ores containing 0.004 to 7% U is described. It is simple, rapid and requires no prior separations from elements that, in other methods, frequently interfere. For sample materials having very high concentrations of interfering elements, a prior concentration step using extraction with tri-n-octylphosphine oxide is described, but it is shown that, for most low-grade ores, this step is unnecessary. (author)

  18. Application of a Simplified Method for Estimating Perfusion Derived from Diffusion-Weighted MR Imaging in Glioma Grading.

    Science.gov (United States)

    Cao, Mengqiu; Suo, Shiteng; Han, Xu; Jin, Ke; Sun, Yawen; Wang, Yao; Ding, Weina; Qu, Jianxun; Zhang, Xiaohua; Zhou, Yan

    2017-01-01

    Purpose : To evaluate the feasibility of a simplified method based on diffusion-weighted imaging (DWI) acquired with three b -values to measure tissue perfusion linked to microcirculation, to validate it against from perfusion-related parameters derived from intravoxel incoherent motion (IVIM) and dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging, and to investigate its utility to differentiate low- from high-grade gliomas. Materials and Methods : The prospective study was approved by the local institutional review board and written informed consent was obtained from all patients. From May 2016 and May 2017, 50 patients confirmed with glioma were assessed with multi- b -value DWI and DCE MR imaging at 3.0 T. Besides conventional apparent diffusion coefficient (ADC 0,1000 ) map, perfusion-related parametric maps for IVIM-derived perfusion fraction ( f ) and pseudodiffusion coefficient (D*), DCE MR imaging-derived pharmacokinetic metrics, including K trans , v e and v p , as well as a metric named simplified perfusion fraction (SPF), were generated. Correlation between perfusion-related parameters was analyzed by using the Spearman rank correlation. All imaging parameters were compared between the low-grade ( n = 19) and high-grade ( n = 31) groups by using the Mann-Whitney U test. The diagnostic performance for tumor grading was evaluated with receiver operating characteristic (ROC) analysis. Results : SPF showed strong correlation with IVIM-derived f and D* ( ρ = 0.732 and 0.716, respectively; both P simplified method to measure tissue perfusion based on DWI by using three b -values may be helpful to differentiate low- from high-grade gliomas. SPF may serve as a valuable alternative to measure tumor perfusion in gliomas in a noninvasive, convenient and efficient way.

  19. Colposcopic triage methods for detecting cervical intraepithelial neoplasia grade 3 after cytopathological diagnosis of low-grade squamous intraepithelial lesion: a systematic review on diagnostic tests

    Directory of Open Access Journals (Sweden)

    Flávia de Miranda Corrêa

    Full Text Available CONTEXT AND OBJECTIVE: The age-stratified performance of the oncogenic HPV-DNA (human papillomavirus deoxyribonucleic acid test for triage of low-grade squamous intraepithelial lesions (LSIL requires investigation. The objective of this study was to evaluate and compare the age-stratified performance (cutoff point: 35 years of oncogenic HPV-DNA testing and repeated cytological tests, for detecting cervical intraepithelial neoplasia grade 3 (CIN3, in order to triage for LSIL. DESIGN AND SETTING: Systematic review. Studies were identified in nine electronic databases and in the reference lists of the articles retrieved. METHODS: The eligibility criteria consisted of initial cytological findings of LSIL; subsequent oncogenic HPV-DNA testing and repeated cytological tests; and CIN3 detection. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS guidelines were used for quality assessment. Qualitative information synthesis was performed. RESULTS: Out of 7,776 studies, 284 were identified as pertinent and three fulfilled the eligibility criteria. The CIN3 prevalence ranged from 6% to 12%. The HPV-DNA positivity rate ranged from 64% to 83%; sensitivity for CIN3 detection ranged from 95.2% to 100%; and specificity was available in two studies (27% and 52%. The sensitivity of repeated cytological tests, in relation to the threshold for atypical squamous cells of undetermined significance (ASCUS, was available in two studies (33% and 90.8%; and specificity was available in one study (53%. CONCLUSIONS: Currently, there is no scientific evidence available that would prove that colposcopic triage using oncogenic HPV-DNA testing to detect CIN3 performs better than repeated cytological tests, among women with LSIL aged 35 years and over.

  20. MRI findings of the knee in rheumatoid arthritis

    International Nuclear Information System (INIS)

    Kanno, Hiromasa; Yuasa, Shoichi; Choukan, Toshinori; Oonuma, Shinichi; Matsunaga, Toshiki

    1996-01-01

    The studies were done to know in what extent MRI can image the pannus invasion and cysts in the subcartilagious tissues which are not revealed by the scout roentgenogram and how the synovial membrane can be enhanced by gadolinium-DTPA (Gd-DTPA). Twenty five knees in rheumatoid arthritis of 21 patients, mean age of 57.8 years, were subjected to the studies. Thirteen knees were in Larsen grade 0, 3 in grade I, 4 in grade II, 2 in grade III and 3 in grade IV, whose osteolytic degree were small. MRI system was 0.5 Tesla superconducting Toshiba MRT50A. Imaging was performed by the field echo method with 4 mm-thick slice of T1, T2 weighted images of sagittal and frontal sections, and 5 min after intravenous injection of Gd-DTPA, of T1 weighted images of frontal and sagittal sections. Subcartilagious cysts not detectable on the scout roentgenogram were found in 13 knees (52%) on the MRI image. MRI after Gd-DTPA gave the enhanced images of surroundings of joint capsule in 15 cases, of dotted or reticular synovial membrane in 2 and of joint capsule surroundings with dotted membrane in 2. One case showed no enhancement. MRI was thus found useful for detection of cysts and pannus in the early knee rheumatoid arthritis with insignificant osteolysis. MRI after Gd-DTPA enhanced the surroundings of joint capsule in most cases, and in some cases, the synovial membrane in a dotted or reticular manner, which was considered to show the dilated blood vessels or necrotic coagulations of synovial villi. (H.O.)

  1. MRI findings of the knee in rheumatoid arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, Hiromasa; Yuasa, Shoichi; Choukan, Toshinori; Oonuma, Shinichi; Matsunaga, Toshiki [Jusendo General Hospital, Koriyama, Fukushima (Japan)

    1996-03-01

    The studies were done to know in what extent MRI can image the pannus invasion and cysts in the subcartilagious tissues which are not revealed by the scout roentgenogram and how the synovial membrane can be enhanced by gadolinium-DTPA (Gd-DTPA). Twenty five knees in rheumatoid arthritis of 21 patients, mean age of 57.8 years, were subjected to the studies. Thirteen knees were in Larsen grade 0, 3 in grade I, 4 in grade II, 2 in grade III and 3 in grade IV, whose osteolytic degree were small. MRI system was 0.5 Tesla superconducting Toshiba MRT50A. Imaging was performed by the field echo method with 4 mm-thick slice of T1, T2 weighted images of sagittal and frontal sections, and 5 min after intravenous injection of Gd-DTPA, of T1 weighted images of frontal and sagittal sections. Subcartilagious cysts not detectable on the scout roentgenogram were found in 13 knees (52%) on the MRI image. MRI after Gd-DTPA gave the enhanced images of surroundings of joint capsule in 15 cases, of dotted or reticular synovial membrane in 2 and of joint capsule surroundings with dotted membrane in 2. One case showed no enhancement. MRI was thus found useful for detection of cysts and pannus in the early knee rheumatoid arthritis with insignificant osteolysis. MRI after Gd-DTPA enhanced the surroundings of joint capsule in most cases, and in some cases, the synovial membrane in a dotted or reticular manner, which was considered to show the dilated blood vessels or necrotic coagulations of synovial villi. (H.O.)

  2. A case report of pseudoprogression followed by complete remission after proton-beam irradiation for a low-grade glioma in a teenager: the value of dynamic contrast-enhanced MRI

    International Nuclear Information System (INIS)

    Meyzer, Candice; Dhermain, Frédéric; Ducreux, Denis; Habrand, Jean-Louis; Varlet, Pascale; Sainte-Rose, Christian; Dufour, Christelle; Grill, Jacques

    2010-01-01

    A fourteen years-old boy was treated post-operatively with proton therapy for a recurrent low-grade oligodendroglioma located in the tectal region. Six months after the end of irradiation (RT), a new enhancing lesion appeared within the radiation fields. To differentiate disease progression from radiation-induced changes, dynamic susceptibility contrast-enhanced (DSCE) MRI was used with a T2* sequence to study perfusion and permeability characteristics simultaneously. Typically, the lesion showed hypoperfusion and hyperpermeability compared to the controlateral normal brain. Without additional treatment but a short course of steroids, the image disappeared over a six months period allowing us to conclude for a pseudo-progression. The patient is alive in complete remission more than 2 years post-RT

  3. Evaluation by discrete element method (DEM) of gap-graded packing potentialities for green concrete design

    NARCIS (Netherlands)

    Stroeven, P.; Le, L.B.N.

    2013-01-01

    Partial replacement of Portland cement by pozzolanic mineral admixtures exerts direct positive effects on CO2 emissions. The green character is reinforced by making use of incinerated vegetable waste, such as rice husk ash (RHA). Gap-grading leads to improved particle packing density with RHA as the

  4. Software V and V methods for a safety - grade programmable logic controller

    International Nuclear Information System (INIS)

    Jang Yeol Kim; Young Jun Lee; Kyung Ho Cha; Se Woo Cheon; Jang Soo Lee; Kee Choon Kwon

    2006-01-01

    This paper addresses the Verification and Validation(V and V) process and the methodology for an embedded real time software of a safety-grade Programmable Logic Controller(PLC). This safety- grade PLC is being developed as one of the Korean Nuclear Instrumentation and Control System (KNICS) projects. KNICS projects are developing a Reactor Protection System(RPS) and an Engineered Safety Feature-Component Control System(ESF-CCS) as well as a safety-grade PLC. The safety-grade PLC will be a major component that encomposes the RPS systems and the ESF-CCS systems as nuclear instruments and control equipment. This paper describes the V and V guidelines and procedures, V and V environment, V and V process and methodology, and the V and V tools in the KNICS projects. Specifically, it describes the real-time operating system V and V experience which corresponds to the requirement analysis phase, design phase and the implementation and testing phase of the software development life cycle. Main activities of the V and V for the PLC system software are a technical evaluation, licensing suitability evaluation, inspection and traceability analysis, formal verification, software safety analysis, and a software configuration management. The proposed V and V methodology satisfies the Standard Review Plan(SRP)/Branch Technical Position(BTP)-14 criteria for the safety software in nuclear power plants. The proposed V and V methodology is going to be used to verify the upcoming software life cycle in the KNICS projects. (author)

  5. An Investigation of Fraction Models in Early Elementary Grades: A Mixed-Methods Approach

    Science.gov (United States)

    Wilkerson, Trena L.; Cooper, Susan; Gupta, Dittika; Montgomery, Mark; Mechell, Sara; Arterbury, Kristin; Moore, Sherrie; Baker, Betty Ruth; Sharp, Pat T.

    2015-01-01

    This study examines the effect varying models have on student understanding of fractions. The study addressed the question of what students know and understand about fractional concepts through the use of discrete and continuous models. A sample of 54 students in kindergarten and 3rd grade were given an interview pretest, participated in…

  6. Relaxation parameter estimation and comparison of NLS and LLS methods for DCE MRI in the cervix

    DEFF Research Database (Denmark)

    Mariager, Christian; Kallehauge, Jesper; Tanderup, Kari

    Dynamic Contrast Enhanced (DCE) MRI is a promising tool for tumor treatment planning. However, prior knowledge of the T1 value within each tumor voxel is needed to utilize this technique. Therefore, a T1 relaxation measurement is performed before the DCE experiment to establish a baseline, before...... any injection of contrast agent. This T1 relaxation measurement is often performed using a variable flip angle spoiled gradient recalled echo (SPGR) sequence. T1 can then be estimated using either a linear least squares (LLS) or a non-linear least squares (NLS) fitting algorithm....

  7. An improved cylindrical FDTD method and its application to field-tissue interaction study in MRI.

    Science.gov (United States)

    Chi, Jieru; Liu, Feng; Xia, Ling; Shao, Tingting; Mason, David G; Crozier, Stuart

    2010-01-01

    This paper presents a three dimensional finite-difference time-domain (FDTD) scheme in cylindrical coordinates with an improved algorithm for accommodating the numerical singularity associated with the polar axis. The regularization of this singularity problem is entirely based on Ampere's law. The proposed algorithm has been detailed and verified against a problem with a known solution obtained from a commercial electromagnetic simulation package. The numerical scheme is also illustrated by modeling high-frequency RF field-human body interactions in MRI. The results demonstrate the accuracy and capability of the proposed algorithm.

  8. Credible knowledge: A pilot evaluation of a modified GRADE method using parent-implemented interventions for children with autism

    Directory of Open Access Journals (Sweden)

    Perry Adrienne

    2011-03-01

    Full Text Available Abstract Background Decision-making in child and youth mental health (CYMH care requires recommendations that are developed through an efficient and effective method and are based on credible knowledge. Credible knowledge is informed by two sources: scientific evidence, and practice-based evidence, that reflects the "real world" experience of service providers. Current approaches to developing these recommendations in relation to CYMH will typically include evidence from one source or the other but do not have an objective method to combine the two. To this end, a modified version of the Grading Recommendations Assessment, Development and Evaluation (GRADE approach was pilot-tested, a novel method for the CYMH field. Methods GRADE has an explicit methodology that relies on input from scientific evidence as well as a panel of experts. The panel established the quality of evidence and derived detailed recommendations regarding the organization and delivery of mental health care for children and youth or their caregivers. In this study a modified GRADE method was used to provide precise recommendations based on a specific CYMH question (i.e. What is the current credible knowledge concerning the effects of parent-implemented, early intervention with their autistic children?. Results Overall, it appeared that early, parent-implemented interventions for autism result in positive effects that outweigh any undesirable effects. However, as opposed to overall recommendations, the heterogeneity of the evidence required that recommendations be specific to particular interventions, based on the questions of whether the benefits of a particular intervention outweighs its harms. Conclusions This pilot project provided evidence that a modified GRADE method may be an effective and practical approach to making recommendations in CYMH, based on credible knowledge. Key strengths of the process included separating the assessments of the quality of the evidence and

  9. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Free Acid by Titration in an Oxalate Solution 8 to 15 Free Acid by Iodate Precipitation-Potentiometric Titration Test Method 16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33 Thorium by Thorin Spectrophotometric Test Method 34 to 42 Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50 Impurities by ICP-AES Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58 Fluoride by Distillation-Spectrophotometric Test Method 59 to 66 Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74 Isotopic Composition by Mass Spectrom...

  10. Boundary element method for normal non-adhesive and adhesive contacts of power-law graded elastic materials

    Science.gov (United States)

    Li, Qiang; Popov, Valentin L.

    2018-03-01

    Recently proposed formulation of the boundary element method for adhesive contacts has been generalized for contacts of power-law graded materials with and without adhesion. Proceeding from the fundamental solution for single force acting on the surface of an elastic half space, first the influence matrix is obtained for a rectangular grid. The inverse problem for the calculation of required stress in the contact area from a known surface displacement is solved using the conjugate-gradient technique. For the transformation between the stresses and displacements, the Fast Fourier Transformation is used. For the adhesive contact of graded material, the detachment criterion based on the energy balance is proposed. The method is validated by comparison with known exact analytical solutions as well as by proving the independence of the mesh size and the grid orientation.

  11. Optimal MRI methods for direct stereotactic targeting of the subthalamic nucleus and globus pallidus

    International Nuclear Information System (INIS)

    O'Gorman, Ruth L.; Shmueli, Karin; Ashkan, Keyoumars; Selway, Richard P.; Samuel, Michael; Lythgoe, David J.; Shahidiani, Asal; Wastling, Stephen J.; Footman, Michelle; Jarosz, Jozef

    2011-01-01

    Reliable identification of the subthalamic nucleus (STN) and globus pallidus interna (GPi) is critical for deep brain stimulation (DBS) of these structures. The purpose of this study was to compare the visibility of the STN and GPi with various MRI techniques and to assess the suitability of each technique for direct stereotactic targeting. MR images were acquired from nine volunteers with T2- and proton density-weighted (PD-W) fast spin echo, susceptibility-weighted imaging (SWI), phase-sensitive inversion recovery and quantitative T1, T2 and T2 * mapping sequences. Contrast-to-noise ratios (CNR) for the STN and GPi were calculated for all sequences. Targeting errors on SWI were evaluated on magnetic susceptibility maps. The sequences demonstrating the best conspicuity of DBS target structures (SWI and T2*) were then applied to ten patients with movement disorders, and the CNRs for these techniques were assessed. SWI offers the highest CNR for the STN, but standard PD-W images provide the best CNR for the pallidum. Susceptibility maps indicated that the GPi margins may be shifted slightly on SWI, although no shifts were seen for the STN. SWI may improve the visibility of the STN on pre-operative MRI, potentially improving the accuracy of direct stereotactic targeting. (orig.)

  12. MRI-Guided Focused Ultrasound as a New Method of Drug Delivery

    Directory of Open Access Journals (Sweden)

    M. Thanou

    2013-01-01

    Full Text Available Ultrasound-mediated drug delivery under the guidance of an imaging modality can improve drug disposition and achieve site-specific drug delivery. The term focal drug delivery has been introduced to describe the focal targeting of drugs in tissues with the help of imaging and focused ultrasound. Focal drug delivery aims to improve the therapeutic profile of drugs by improving their specificity and their permeation in defined areas. Focused-ultrasound- (FUS- mediated drug delivery has been applied with various molecules to improve their local distribution in tissues. FUS is applied with the aid of microbubbles to enhance the permeability of bioactive molecules across BBB and improve drug distribution in the brain. Recently, FUS has been utilised in combination with MRI-labelled liposomes that respond to temperature increase. This strategy aims to “activate” nanoparticles to release their cargo locally when triggered by hyperthermia induced by FUS. MRI-guided FUS drug delivery provides the opportunity to improve drug bioavailability locally and therefore improve the therapeutic profiles of drugs. This drug delivery strategy can be directly translated to clinic as MRg FUS is a promising clinically therapeutic approach. However, more basic research is required to understand the physiological mechanism of FUS-enhanced drug delivery.

  13. A new method to grade glass eels according to their appetite

    Directory of Open Access Journals (Sweden)

    ANGELIDIS Panagiotis

    2007-10-01

    Full Text Available To optimize fish growth grading is strongly recommended. In our experiment the glass eels (450,000, mean individual body weight 0.31+0.22g sd start feeding for 15 and then they were selected according to their appetite. After selection all the fish of the 10 tanks were fed at liberty and they were weighed on the 10th and 30thday after the grade day. No differences were seen in the fish weight of the eels of the two groups on the 10th day (P>0.01 but the selected fish doubled their weight on the 30th day (selected fish 0.71+0.22g sd, unselected 0.39+0.20g sd, P<0.01.

  14. Method for making graded I-III-VI.sub.2 semiconductors and solar cell obtained thereby

    Science.gov (United States)

    Devaney, Walter E.

    1987-08-04

    Improved cell photovoltaic conversion efficiencies are obtained by the simultaneous elemental reactive evaporation process of Mickelsen and Chen for making semiconductors by closer control of the evaporation rates and substrate temperature during formation of the near contact, bulk, and near junction regions of a graded I-III-VI.sub.2, thin film, semiconductor, such as CuInSe.sub.2 /(Zn,Cd)S or another I-III-VI.sub.2 /II-VI heterojunction.

  15. Evaluation by discrete element method (DEM) of gap-graded packing potentialities for green concrete design

    OpenAIRE

    Stroeven, P.; Le, L.B.N.

    2013-01-01

    Partial replacement of Portland cement by pozzolanic mineral admixtures exerts direct positive effects on CO2 emissions. The green character is reinforced by making use of incinerated vegetable waste, such as rice husk ash (RHA). Gap-grading leads to improved particle packing density with RHA as the fine component, so that high strength concrete can be produced. Characteristics of the capillary pores developed in the hydrating binder have impact on the transport-based durability properties. Y...

  16. In the assessment of supratentorial glioma grade: The combined role of multivoxel proton MR spectroscopy and diffusion tensor imaging

    International Nuclear Information System (INIS)

    Zou, Q.-G.; Xu, H.-B.; Liu, F.; Guo, W.; Kong, X.-C.; Wu, Y.

    2011-01-01

    Aim: To detect a difference in the parameters derived from proton magnetic resonance spectroscopy ( 1 H-MRS) and diffusion tensor imaging (DTI) between low-grade and high-grade gliomas, and to evaluate whether the combination of these two techniques can improve the diagnostic accuracy of conventional magnetic resonance imaging (MRI) in supratentorial glioma grading. Materials and methods: Thirty patients with histologically proved supratentorial brain gliomas (12 low grade, 18 high grade) were prospectively evaluated with contrast material-enhanced MRI, DTI, and multivoxel 1 H-MRS (135 ms echo time). The tumour grades determined using the three methods were then compared with those obtained at histopathology. Receiver operating characteristic (ROC) analyses were performed to determine the optimum thresholds for glioma grading. Independent sample t-test, Spearman's rank correlation, and the Fisher's exact test were also carried out for statistical analysis. p -6 mm 2 /s for the calculated ADC value, corresponding to the maximum Youden index from the ROC curve of the above-selected parameters, the resultant sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Kappa values were all higher and the fraction of misclassified tumour was lower when compared with conventional MRI. However, only NAA/Cho and ADC calculation contributed to the significant difference (p < 0.01) in the assessment of glioma grade compared to conventional MRI alone, and the grading results of statistical tests comparing those two parameters were highly consistent (kappa value = 0.798). Conclusion: Thresholds for NAA/Cho and calculated ADC values, corresponding to maximum Youden index from ROC curve analyses, helped to improve the accuracy of supratentorial glioma grading when compared with conventional MRI alone. In addition, a combination of NAA/Cho and ADC calculation were more useful together than each alone in a clinical setting to evaluate

  17. Metallic artifact in MRI after removal of orthopedic implants

    International Nuclear Information System (INIS)

    Bagheri, Mohammad Hadi; Hosseini, Mehrdad Mohammad; Emami, Mohammad Jafar; Foroughi, Amin Aiboulhassani

    2012-01-01

    Objective: The aim of the present study was to evaluate the metallic artifacts in MRI of the orthopedic patients after removal of metallic implants. Subjects and methods: From March to August 2009, 40 orthopedic patients operated for removal of orthopedic metallic implants were studied by post-operative MRI from the site of removal of implants. A grading scale of 0–3 was assigned for artifact in MR images whereby 0 was considered no artifact; and I–III were considered mild, moderate, and severe metallic artifacts, respectively. These grading records were correlated with other variables including the type, size, number, and composition of metallic devices; and the site and duration of orthopedic devices stay in the body. Results: Metallic susceptibly artifacts were detected in MRI of 18 of 40 cases (45%). Screws and pins in removed hardware were the most important factors for causing artifacts in MRI. The artifacts were found more frequently in the patients who had more screws and pins in the removed implants. Gender, age, site of implantation of the device, length of the hardware, composition of the metallic implants (stainless steel versus titanium), and duration of implantation of the hardware exerted no effect in producing metallic artifacts after removal of implants. Short TE sequences of MRI (such as T1 weighted) showed fewer artifacts. Conclusion: Susceptibility of metallic artifacts is a frequent phenomenon in MRI of patients upon removal of metallic orthopedic implants.

  18. A novel method to assess pial collateralization from stroke perfusion MRI: subdividing T{sub max} into anatomical compartments

    Energy Technology Data Exchange (ETDEWEB)

    Potreck, Arne; Seker, Fatih; Hoffmann, Angelika; Pfaff, Johannes; Bendszus, Martin; Heiland, Sabine; Pham, Mirko [Heidelberg University Hospital, Department of Neuroradiology, Heidelberg (Germany); Nagel, Simon [Heidelberg University Hospital, Department of Neurology, Heidelberg (Germany)

    2017-02-15

    To develop and validate a quantitative and observer-independent method to evaluate pial collateral circulation by DSC-perfusion MRI and test whether this novel method delivers diagnostic information which is redundant to or independent from conventional penumbra imaging by the mismatch approach. We retrospectively identified 47 patients with M1 occlusion who underwent MR diffusion/perfusion imaging and mechanical thrombectomy at our facility. By automated registration and segmentation, T{sub max} delays were attributed specifically to the pial, cortical and parenchymal compartments. The resulting pial volumes at delay were defined as the pial T{sub max} map-assessed collateral score (TMACS) and correlated with gold standard digital subtraction angiography (DSA). Mismatch ratio was assessed by conventional penumbra defining MRI criteria. Strong correlation was found between TMACS and angiographically assessed collateral score (Pearson ρ = -0.74, p < 0.001). In multiple logistic regression, both good collaterals according to TMACS [OR 4.3 (1.1-19, p = 0.04)] and mismatch ratio ≥ 3.5 [OR 12.3 (1.88-249, p = 0.03)] were independent predictors of favourable clinical outcome. Perfusion delay in the pial compartment, as evaluated by TMACS, closely reflects the extent of pial collaterals in gold-standard DSA. TMACS and mismatch ratio were found to be complementary predictors of a favourable clinical outcome, each adding independent predictive information. (orig.)

  19. Quantitative evaluation of polymer concentration profile during swelling of hydrophilic matrix tablets using 1H NMR and MRI methods.

    Science.gov (United States)

    Baumgartner, Sasa; Lahajnar, Gojmir; Sepe, Ana; Kristl, Julijana

    2005-02-01

    Many pharmaceutical tablets are based on hydrophilic polymers, which, after exposure to water, form a gel layer around the tablet that limits the dissolution and diffusion of the drug and provides a mechanism for controlled drug release. Our aim was to determine the thickness of the swollen gel layer of matrix tablets and to develop a method for calculating the polymer concentration profile across the gel layer. MR imaging has been used to investigate the in situ swelling behaviour of cellulose ether matrix tablets and NMR spectroscopy experiments were performed on homogeneous hydrogels with known polymer concentration. The MRI results show that the thickest gel layer was observed for hydroxyethylcellulose tablets, followed by definitely thinner but almost equal gel layer for hydroxypropylcellulose and hydroxypropylmethylcellulose of both molecular weights. The water proton NMR relaxation parameters were combined with the MRI data to obtain a quantitative description of the swelling process on the basis of the concentrations and mobilities of water and polymer as functions of time and distance. The different concentration profiles observed after the same swelling time are the consequence of the different polymer characteristics. The procedure developed here could be used as a general method for calculating polymer concentration profiles on other similar polymeric systems.

  20. Application of a Simplified Method for Estimating Perfusion Derived from Diffusion-Weighted MR Imaging in Glioma Grading

    Directory of Open Access Journals (Sweden)

    Mengqiu Cao

    2018-01-01

    Full Text Available Purpose: To evaluate the feasibility of a simplified method based on diffusion-weighted imaging (DWI acquired with three b-values to measure tissue perfusion linked to microcirculation, to validate it against from perfusion-related parameters derived from intravoxel incoherent motion (IVIM and dynamic contrast-enhanced (DCE magnetic resonance (MR imaging, and to investigate its utility to differentiate low- from high-grade gliomas.Materials and Methods: The prospective study was approved by the local institutional review board and written informed consent was obtained from all patients. From May 2016 and May 2017, 50 patients confirmed with glioma were assessed with multi-b-value DWI and DCE MR imaging at 3.0 T. Besides conventional apparent diffusion coefficient (ADC0,1000 map, perfusion-related parametric maps for IVIM-derived perfusion fraction (f and pseudodiffusion coefficient (D*, DCE MR imaging-derived pharmacokinetic metrics, including Ktrans, ve and vp, as well as a metric named simplified perfusion fraction (SPF, were generated. Correlation between perfusion-related parameters was analyzed by using the Spearman rank correlation. All imaging parameters were compared between the low-grade (n = 19 and high-grade (n = 31 groups by using the Mann-Whitney U test. The diagnostic performance for tumor grading was evaluated with receiver operating characteristic (ROC analysis.Results: SPF showed strong correlation with IVIM-derived f and D* (ρ = 0.732 and 0.716, respectively; both P < 0.001. Compared with f, SPF was more correlated with DCE MR imaging-derived Ktrans (ρ = 0.607; P < 0.001 and vp (ρ = 0.397; P = 0.004. Among all parameters, SPF achieved the highest accuracy for differentiating low- from high-grade gliomas, with an area under the ROC curve value of 0.942, which was significantly higher than that of ADC0,1000 (P = 0.004. By using SPF as a discriminative index, the diagnostic sensitivity and specificity were 87.1% and 94

  1. Comparison between modified Dixon MRI techniques, MR spectroscopic relaxometry, and different histologic quantification methods in the assessment of hepatic steatosis

    Energy Technology Data Exchange (ETDEWEB)

    Kukuk, Guido M.; Block, Wolfgang; Willinek, Winfried A.; Schild, Hans H.; Traeber, Frank [University of Bonn, Department of Radiology, Bonn (Germany); Hittatiya, Kanishka; Fischer, Hans-Peter [University of Bonn, Department of Pathology, Bonn (Germany); Sprinkart, Alois M. [University of Bonn, Department of Radiology, Bonn (Germany); Ruhr-University, Institute of Medical Engineering, Bochum (Germany); Eggers, Holger [Philips Research Europe, Hamburg (Germany); Gieseke, Juergen [University of Bonn, Department of Radiology, Bonn (Germany); Philips Healthcare, Best (Netherlands); Moeller, Philipp; Spengler, Ulrich; Trebicka, Jonel [University of Bonn, Department of Internal Medicine I, Bonn (Germany)

    2015-10-15

    To compare systematically quantitative MRI, MR spectroscopy (MRS), and different histological methods for liver fat quantification in order to identify possible incongruities. Fifty-nine consecutive patients with liver disorders were examined on a 3 T MRI system. Quantitative MRI was performed using a dual- and a six-echo variant of the modified Dixon (mDixon) sequence, calculating proton density fat fraction (PDFF) maps, in addition to single-voxel MRS. Histological fat quantification included estimation of the percentage of hepatocytes containing fat vesicles as well as semi-automatic quantification (qHisto) using tissue quantification software. In 33 of 59 patients, the hepatic fat fraction was >5 % as determined by MRS (maximum 45 %, mean 17 %). Dual-echo mDixon yielded systematically lower PDFF values than six-echo mDixon (mean difference 1.0 %; P < 0.001). Six-echo mDixon correlated excellently with MRS, qHisto, and the estimated percentage of hepatocytes containing fat vesicles (R = 0.984, 0.967, 0.941, respectively, all P < 0.001). Mean values obtained by the estimated percentage of hepatocytes containing fat were higher by a factor of 2.5 in comparison to qHisto. Six-echo mDixon and MRS showed the best agreement with values obtained by qHisto. Six-echo mDixon, MRS, and qHisto provide the most robust and congruent results and are therefore most appropriate for reliable quantification of liver fat. (orig.)

  2. A new MRI method for the quantitative evaluation of extraocular muscle size in thyroid ophthalmopathy

    International Nuclear Information System (INIS)

    Aydin, K.; Gueven, K.; Sencer, S.; Minareci, O.; Cikim, A.; Guel, N.

    2003-01-01

    In cross section, extraocular muscles are more or less elliptical, with short and long diameters. We studied the ratio (R) of short to long diameter and investigated its use in quantitative assessment of the extraocular muscles in patients with Graves's disease. We measured the diameters on T1-weighted axial and coronal MRI and computed R for each extraocular muscle in 80 patients without and 40 with Graves's disease. We compared the measurements and R of the right and left orbits, and of men and women. The short diameter of all extraocular muscles apart from the superior oblique showed significant differences between men and women, and that of the inferior rectus varied significantly with age. R, however, was unrelated to sex or age. All patients with Graves's disease and an increased short diameter also had an increased R, but 6% of the muscles showed an increase in R, even though their short diameter was within the normal range. (orig.)

  3. Usefulness of 3D-VIBE method in breast dynamic MRI. Imaging parameters and contrasting effects

    International Nuclear Information System (INIS)

    Uchikoshi, Masato; Ueda, Takashi; Nishiki, Shigeo; Satou, Kouichi; Wada, Akihiko; Imaoka, Izumi; Matsuo, Michimasa

    2003-01-01

    MR imaging (MRI) has been reported to be a useful modality to characterize breast tumors and to evaluate disease extent. Contrast-enhanced dynamic MRI, in particular, allows breast lesions to be characterized with high sensitivity and specificity. Our study was designed to develop three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) techniques for the evaluation of breast tumors. First, agarose/Gd-DTPA phantoms with various concentrations of Gd-DTPA were imaged using 3D-VIBE and turbo spin echo (TSE). Second, one of the phantoms was imaged with 3D-VIBE using different flip angles. Finally, water excitation (WE) and a chemical shift-selective (CHESS) pulse were applied to the images. Each image was analyzed for signal intensity, signal-to-noise ratio (1.25*Ms/Mb) (SNR), and contrast ratio [(Ms1-Ms2)/{(Ms1+Ms2)/2}]. The results showed that 3D-VIBE provided better contrast ratios with a linear fit than TSE, although 3D-VIBE showed a lower SNR. To reach the best contrast ratio, the optimized flip angle was found to be 30 deg for contrast-enhanced dynamic study. Both WE and CHESS pulses were reliable for obtaining fat- suppressed images. In conclusion, the 3D-VIBE technique can image the entire breast area with high resolution and provide better contrast than TSE. Our phantom study suggests that optimized 3D-VIBE may be useful for the assessment of breast tumors. (author)

  4. Bernstein method for the MHD flow and heat transfer of a second grade fluid in a channel with porous wall

    Directory of Open Access Journals (Sweden)

    A. Sami Bataineh

    2016-09-01

    Full Text Available In this paper, we present an approximate solution method for the problem of magnetohydrodynamic (MHD flow and heat transfer of a second grade fluid in a channel with a porous wall. The method is based on the Bernstein polynomials with their operational matrices and collocation method. Under some regularity conditions, upper bounds of the absolute errors are given. We apply the residual correction procedure which may estimate the absolute error to the problem. We may estimate the absolute error by using a procedure depends on the sequence of the approximate solutions. For some certain cases, we apply the method to the problem in the numerical examples. Moreover, we test the impact of changing the flow parameters numerically. The results are consistent with the results of Runge-Kutta fourth order method and homotopy analysis method.

  5. Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

  6. Comparative evaluation of the powder and compression properties of various grades and brands of microcrystalline cellulose by multivariate methods.

    Science.gov (United States)

    Haware, Rahul V; Bauer-Brandl, Annette; Tho, Ingunn

    2010-01-01

    The present work challenges a newly developed approach to tablet formulation development by using chemically identical materials (grades and brands of microcrystalline cellulose). Tablet properties with respect to process and formulation parameters (e.g. compression speed, added lubricant and Emcompress fractions) were evaluated by 2(3)-factorial designs. Tablets of constant true volume were prepared on a compaction simulator at constant pressure (approx. 100 MPa). The highly repeatable and accurate force-displacement data obtained was evaluated by simple 'in-die' Heckel method and work descriptors. Relationships and interactions between formulation, process and tablet parameters were identified and quantified by multivariate analysis techniques; principal component analysis (PCA) and partial least square regressions (PLS). The method proved to be able to distinguish between different grades of MCC and even between two different brands of the same grade (Avicel PH 101 and Vivapur 101). One example of interaction was studied in more detail by mixed level design: The interaction effect of lubricant and Emcompress on elastic recovery of Avicel PH 102 was demonstrated to be complex and non-linear using the development tool under investigation.

  7. Needs and preferences among patients with high-grade glioma and their caregivers - A longitudinal mixed methods study

    DEFF Research Database (Denmark)

    Piil, K; Jakobsen, J; Christensen, K B

    2018-01-01

    Previous reports on the patient perspective of daily life during a 1-year high-grade glioma (HGG) trajectory from the time of diagnosis are sparse. The aim of this longitudinal mixed methods study is to identify the specific needs and preferences for rehabilitation and supportive care and how...... it links with physical activity, psychological measures and health quality longitudinally over the first year after diagnosis among patients with HGG and their caregivers by integrating qualitative and quantitative findings. Using a longitudinal mixed methods design, patients with malignant glioma (n = 30...

  8. The continuous reaction times method for diagnosing, grading, and monitoring minimal/covert hepatic encephalopathy

    DEFF Research Database (Denmark)

    Lauridsen, Mette Enok Munk; Thiele, Maja; Kimer, N

    2013-01-01

    Abstract Existing tests for minimal/covert hepatic encephalopathy (m/cHE) are time- and expertise consuming and primarily useable for research purposes. An easy-to-use, fast and reliable diagnostic and grading tool is needed. We here report on the background, experience, and ongoing research......-10) percentile) as a parameter of reaction time variability. The index is a measure of alertness stability and is used to assess attention and cognition deficits. The CRTindex identifies half of patients in a Danish cohort with chronic liver disease, as having m/cHE, a normal value safely precludes HE, it has...

  9. Dating of zircon from high-grade rocks: Which is the most reliable method?

    Directory of Open Access Journals (Sweden)

    Alfred Kröner

    2014-07-01

    Full Text Available Magmatic zircon in high-grade metamorphic rocks is often characterized by complex textures as revealed by cathodoluminenscence (CL that result from multiple episodes of recrystallization, overgrowth, Pb-loss and modifications through fluid-induced disturbances of the crystal structure and the original U-Th-Pb isotopic systematics. Many of these features can be recognized in 2-dimensional CL images, and isotopic analysis of such domains using a high resolution ion-microprobe with only shallow penetration of the zircon surface may be able to reconstruct much of the magmatic and complex post-magmatic history of such grains. In particular it is generally possible to find original magmatic domains yielding concordant ages. In contrast, destructive techniques such as LA-ICP-MS consume a large volume, leave a deep crater in the target grain, and often sample heterogeneous domains that are not visible and thus often yield discordant results which are difficult to interpret. We provide examples of complex magmatic zircon from a southern Indian granulite terrane where SHRIMP II and LA-ICP-MS analyses are compared. The SHRIMP data are shown to be more precise and reliable, and we caution against the use of LA-ICP-MS in deciphering the chronology of complex zircons from high-grade terranes.

  10. MRI EVALUATION OF TRIGEMINAL NEURALGIA

    Directory of Open Access Journals (Sweden)

    Sama Surya Sravani

    2017-04-01

    Full Text Available BACKGROUND Neuralgia is the set of symptoms associated with nerve dysfunction. The most common of these symptoms is pain, which can occur intermittently in one area of the body or can radiate along the length of a damaged nerve. The most common type of neuralgia is trigeminal neuralgia. This study focuses on the effectiveness of MRI in visualising the entire course of trigeminal nerve and to diagnose the exact location, aetiology responsible for trigeminal neuralgia and possible pretreatment evaluation. MATERIALS AND METHODS Clinical records and imaging studies of 30 patients between the ages of 18-60 years who presented to the Department of Radiodiagnosis, KIMS, for brain magnetic resonance imaging with (Philips 1.5T machine during June 2015 to December 2016 were analysed retrospectively. RESULTS  The entire course of trigeminal nerve is evaluated in these patients.  There are different causes of trigeminal neuralgia, but in our study, most frequent cause is mechanical irritation of nerve is due to neurovascular contact (24 cases. The other causes identified are cerebellopontine angle lesions, brainstem tumours, demyelinating disease involving brainstem.  The cisternal portion of the nerve is the most common site of involvement. CONCLUSION Trigeminal nerve is the largest cranial nerve. MRI is unique as it produces images of entire course of the nerve. Of the many causes of trigeminal neuralgia, neurovascular conflict is the most common cause. The exact location and degree of neurovascular compression is graded on MRI.

  11. Investigation & Comparison in Some Aspects of Phonological Awareness Skill (in both Whole Word & Phonetic Methods in First Grade Female Students

    Directory of Open Access Journals (Sweden)

    Ali Dehghan-Ahmadabad

    2005-04-01

    Full Text Available Objective: Phonological Awareness (PA is a extra linguistic skill and defined as individual awareness of constituent’s sounds of the word . This skill is a prerequisites of learning to Read. Many researchers suggested reciprocal relation between PA and Reading. This research determined level of PA-fundamental ability of reading-in normal first grade femal students of Isfahan & shahinshar to compare two current method of Reading that are used in educational system of Iran. Materials & Methods: The method used in this research is cross-sectional, descriptive-analytic and was done by 106 first grade female students who were normal and selected randomly in Isfahan & shahinshar cities. 51 students had teached by phonetic method and rest of them had teached by whole word method. The selection way of children was: this children had not any articulation, vision, reading, learning and cranial nerve disorders and this children investigated by Phonological Awareness test. scores of children by test calculated and this scores analyzed by t-test in Spss software. Results: The mean score of phonological awareness in phonetic method was 51.98 and in whole word method was 57.46. There was a significant differences between them in their scores (P=0.047. In addition,within subtests of phonological awareness task,mean score of first phoneme omission in whole word method was 4.84 and in phonetic method was 3.33. There was a significant difference between them in their scores (P=0.001. In the rest of subtests was no significant difference between them. Conclusion: Based on this study, a significant correlation could be found in Phonological Awareness between both group and in other hand, there was a significant correlation between scores of first phoneme omission in both groups (Whole word and Phonetic method.Based on importance of phonological awareness as a predictor of reading, we suggest more research in this outline must be done.

  12. Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

    Energy Technology Data Exchange (ETDEWEB)

    Muhle, C. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Brossmann, J. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Melchert, U.H. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Schroeder, C. [Radiologische Abt., Universitaets-Kinderklinik, Christian-Albrechts-Universitaet, Kiel (Germany); Boer, R. de [Philips Medical Systems, Best (Netherlands); Spielmann, R.P. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Heller, M. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany)

    1995-12-31

    To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

  13. Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

    International Nuclear Information System (INIS)

    Muhle, C.; Brossmann, J.; Melchert, U.H.; Schroeder, C.; Boer, R. de; Spielmann, R.P.; Heller, M.

    1995-01-01

    To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

  14. Comparison between PET template-based method and MRI-based method for cortical quantification of florbetapir (AV-45) uptake in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Aubert, L.; Nemmi, F.; Peran, P. [Inserm, Imagerie Cerebrale et Handicaps neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Centre Hospitalier Universitaire de Toulouse, Universite de Toulouse, UPS, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Toulouse (France); Barbeau, E.J. [Universite de Toulouse, UPS, Centre de Recherche Cerveau et Cognition, France, CNRS, CerCo, Toulouse (France); Service de Neurologie, Pole Neurosciences, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Payoux, P. [Inserm, Imagerie Cerebrale et Handicaps neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Centre Hospitalier Universitaire de Toulouse, Universite de Toulouse, UPS, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Toulouse (France); Service de Medecine Nucleaire, Pole Imagerie, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Chollet, F.; Pariente, J. [Inserm, Imagerie Cerebrale et Handicaps neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Centre Hospitalier Universitaire de Toulouse, Universite de Toulouse, UPS, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Toulouse (France); Service de Neurologie, Pole Neurosciences, Centre Hospitalier Universitaire de Toulouse, Toulouse (France)

    2014-05-15

    Florbetapir (AV-45) has been shown to be a reliable tool for assessing in vivo amyloid load in patients with Alzheimer's disease from the early stages. However, nonspecific white matter binding has been reported in healthy subjects as well as in patients with Alzheimer's disease. To avoid this issue, cortical quantification might increase the reliability of AV-45 PET analyses. In this study, we compared two quantification methods for AV-45 binding, a classical method relying on PET template registration (route 1), and a MRI-based method (route 2) for cortical quantification. We recruited 22 patients at the prodromal stage of Alzheimer's disease and 17 matched controls. AV-45 binding was assessed using both methods, and target-to-cerebellum mean global standard uptake values (SUVr) were obtained for each of them, together with SUVr in specific regions of interest. Quantification using the two routes was compared between the clinical groups (intragroup comparison), and between groups for each route (intergroup comparison). Discriminant analysis was performed. In the intragroup comparison, differences in uptake values were observed between route 1 and route 2 in both groups. In the intergroup comparison, AV-45 uptake was higher in patients than controls in all regions of interest using both methods, but the effect size of this difference was larger using route 2. In the discriminant analysis, route 2 showed a higher specificity (94.1 % versus 70.6 %), despite a lower sensitivity (77.3 % versus 86.4 %), and D-prime values were higher for route 2. These findings suggest that, although both quantification methods enabled patients at early stages of Alzheimer's disease to be well discriminated from controls, PET template-based quantification seems adequate for clinical use, while the MRI-based cortical quantification method led to greater intergroup differences and may be more suitable for use in current clinical research. (orig.)

  15. MRI in head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jin Kyo [Shin Wha Hospital, Seoul (Korea, Republic of)

    1986-02-15

    In the diagnosis of head injury, Magnetic Resonance Imaging (MRI), like CT, is an effective method of distinguishing between intracerebral and extracerebral lesions. In our experience of MRI, early hematomas are almost isointense by Saturation Recovery (SR) method, so these must be performed with Spin Echo (SE) method for better visualization of hematomas. Isodense subdural hematomas, which is a diagnostic dilemma on CT images, are clearly seen on MRI. Delayed hematomas or residual parenchymal lesions are better demonstrated on MRI than on CT. Direct cornal, sagittal images and multiplanar facility of MRI provides excellent visualization of the the location and shape of extracerebral collection of hematoma. For the screening of head traumas, SE method is a technique of choice because of its excellent sensitivity within limited time.

  16. MRI in head trauma

    International Nuclear Information System (INIS)

    Hong, Jin Kyo

    1986-01-01

    In the diagnosis of head injury, Magnetic Resonance Imaging (MRI), like CT, is an effective method of distinguishing between intracerebral and extracerebral lesions. In our experience of MRI, early hematomas are almost isointense by Saturation Recovery (SR) method, so these must be performed with Spin Echo (SE) method for better visualization of hematomas. Isodense subdural hematomas, which is a diagnostic dilemma on CT images, are clearly seen on MRI. Delayed hematomas or residual parenchymal lesions are better demonstrated on MRI than on CT. Direct cornal, sagittal images and multiplanar facility of MRI provides excellent visualization of the the location and shape of extracerebral collection of hematoma. For the screening of head traumas, SE method is a technique of choice because of its excellent sensitivity within limited time.

  17. Multilevel Thresholding Method Based on Electromagnetism for Accurate Brain MRI Segmentation to Detect White Matter, Gray Matter, and CSF

    Directory of Open Access Journals (Sweden)

    G. Sandhya

    2017-01-01

    Full Text Available This work explains an advanced and accurate brain MRI segmentation method. MR brain image segmentation is to know the anatomical structure, to identify the abnormalities, and to detect various tissues which help in treatment planning prior to radiation therapy. This proposed technique is a Multilevel Thresholding (MT method based on the phenomenon of Electromagnetism and it segments the image into three tissues such as White Matter (WM, Gray Matter (GM, and CSF. The approach incorporates skull stripping and filtering using anisotropic diffusion filter in the preprocessing stage. This thresholding method uses the force of attraction-repulsion between the charged particles to increase the population. It is the combination of Electromagnetism-Like optimization algorithm with the Otsu and Kapur objective functions. The results obtained by using the proposed method are compared with the ground-truth images and have given best values for the measures sensitivity, specificity, and segmentation accuracy. The results using 10 MR brain images proved that the proposed method has accurately segmented the three brain tissues compared to the existing segmentation methods such as K-means, fuzzy C-means, OTSU MT, Particle Swarm Optimization (PSO, Bacterial Foraging Algorithm (BFA, Genetic Algorithm (GA, and Fuzzy Local Gaussian Mixture Model (FLGMM.

  18. TH-C-BRD-06: A Novel MRI Based CT Artifact Correction Method for Improving Proton Range Calculation in the Presence of Severe CT Artifacts

    International Nuclear Information System (INIS)

    Park, P; Schreibmann, E; Fox, T; Roper, J; Elder, E; Tejani, M; Crocker, I; Curran, W; Dhabaan, A

    2014-01-01

    Purpose: Severe CT artifacts can impair our ability to accurately calculate proton range thereby resulting in a clinically unacceptable treatment plan. In this work, we investigated a novel CT artifact correction method based on a coregistered MRI and investigated its ability to estimate CT HU and proton range in the presence of severe CT artifacts. Methods: The proposed method corrects corrupted CT data using a coregistered MRI to guide the mapping of CT values from a nearby artifact-free region. First patient MRI and CT images were registered using 3D deformable image registration software based on B-spline and mutual information. The CT slice with severe artifacts was selected as well as a nearby slice free of artifacts (e.g. 1cm away from the artifact). The two sets of paired MRI and CT images at different slice locations were further registered by applying 2D deformable image registration. Based on the artifact free paired MRI and CT images, a comprehensive geospatial analysis was performed to predict the correct CT HU of the CT image with severe artifact. For a proof of concept, a known artifact was introduced that changed the ground truth CT HU value up to 30% and up to 5cm error in proton range. The ability of the proposed method to recover the ground truth was quantified using a selected head and neck case. Results: A significant improvement in image quality was observed visually. Our proof of concept study showed that 90% of area that had 30% errors in CT HU was corrected to 3% of its ground truth value. Furthermore, the maximum proton range error up to 5cm was reduced to 4mm error. Conclusion: MRI based CT artifact correction method can improve CT image quality and proton range calculation for patients with severe CT artifacts

  19. A simple method of measuring tibial tubercle to trochlear groove distance on MRI: description of a novel and reliable technique.

    Science.gov (United States)

    Camp, Christopher L; Heidenreich, Mark J; Dahm, Diane L; Bond, Jeffrey R; Collins, Mark S; Krych, Aaron J

    2016-03-01

    Tibial tubercle-trochlear groove (TT-TG) distance is a variable that helps guide surgical decision-making in patients with patellar instability. The purpose of this study was to compare the accuracy and reliability of an MRI TT-TG measuring technique using a simple external alignment method to a previously validated gold standard technique that requires advanced software read by radiologists. TT-TG was calculated by MRI on 59 knees with a clinical diagnosis of patellar instability in a blinded and randomized fashion by two musculoskeletal radiologists using advanced software and by two orthopaedists using the study technique which utilizes measurements taken on a simple electronic imaging platform. Interrater reliability between the two radiologists and the two orthopaedists and intermethods reliability between the two techniques were calculated using interclass correlation coefficients (ICC) and concordance correlation coefficients (CCC). ICC and CCC values greater than 0.75 were considered to represent excellent agreement. The mean TT-TG distance was 14.7 mm (Standard Deviation (SD) 4.87 mm) and 15.4 mm (SD 5.41) as measured by the radiologists and orthopaedists, respectively. Excellent interobserver agreement was noted between the radiologists (ICC 0.941; CCC 0.941), the orthopaedists (ICC 0.978; CCC 0.976), and the two techniques (ICC 0.941; CCC 0.933). The simple TT-TG distance measurement technique analysed in this study resulted in excellent agreement and reliability as compared to the gold standard technique. This method can predictably be performed by orthopaedic surgeons without advanced radiologic software. II.

  20. Cine MRI of dissecting aneurysm

    International Nuclear Information System (INIS)

    Takaki, Hajime

    1991-01-01

    Cine MRI was performed in 25 cases of aortic dissection and comparative study among cine MRI, spin-echo static MRI, contrast-enhanced CT and intravenous digital subtraction angiography (IVDSA) was made. Cine MRI accurately detected aortic dissection. It was most accurate among various diagnostic methods in demonstration of entry site of dissection. Take-off of renal artery and its relation to true and false channels was also accurately demonstrated by cine MRI. The above results suggest that cine MRI can be an important diagnostic modality with almost equal diagnostic quality to those of conventional angiography. However, further technical improvement to shorten the imaging time seems necessary to replace angiography. (author)

  1. A simple method for detecting tumor in T2-weighted MRI brain images. An image-based analysis

    International Nuclear Information System (INIS)

    Lau, Phooi-Yee; Ozawa, Shinji

    2006-01-01

    The objective of this paper is to present a decision support system which uses a computer-based procedure to detect tumor blocks or lesions in digitized medical images. The authors developed a simple method with a low computation effort to detect tumors on T2-weighted Magnetic Resonance Imaging (MRI) brain images, focusing on the connection between the spatial pixel value and tumor properties from four different perspectives: cases having minuscule differences between two images using a fixed block-based method, tumor shape and size using the edge and binary images, tumor properties based on texture values using spatial pixel intensity distribution controlled by a global discriminate value, and the occurrence of content-specific tumor pixel for threshold images. Measurements of the following medical datasets were performed: different time interval images, and different brain disease images on single and multiple slice images. Experimental results have revealed that our proposed technique incurred an overall error smaller than those in other proposed methods. In particular, the proposed method allowed decrements of false alarm and missed alarm errors, which demonstrate the effectiveness of our proposed technique. In this paper, we also present a prototype system, known as PCB, to evaluate the performance of the proposed methods by actual experiments, comparing the detection accuracy and system performance. (author)

  2. Accurate Learning with Few Atlases (ALFA): an algorithm for MRI neonatal brain extraction and comparison with 11 publicly available methods.

    Science.gov (United States)

    Serag, Ahmed; Blesa, Manuel; Moore, Emma J; Pataky, Rozalia; Sparrow, Sarah A; Wilkinson, A G; Macnaught, Gillian; Semple, Scott I; Boardman, James P

    2016-03-24

    Accurate whole-brain segmentation, or brain extraction, of magnetic resonance imaging (MRI) is a critical first step in most neuroimage analysis pipelines. The majority of brain extraction algorithms have been developed and evaluated for adult data and their validity for neonatal brain extraction, which presents age-specific challenges for this task, has not been established. We developed a novel method for brain extraction of multi-modal neonatal brain MR images, named ALFA (Accurate Learning with Few Atlases). The method uses a new sparsity-based atlas selection strategy that requires a very limited number of atlases 'uniformly' distributed in the low-dimensional data space, combined with a machine learning based label fusion technique. The performance of the method for brain extraction from multi-modal data of 50 newborns is evaluated and compared with results obtained using eleven publicly available brain extraction methods. ALFA outperformed the eleven compared methods providing robust and accurate brain extraction results across different modalities. As ALFA can learn from partially labelled datasets, it can be used to segment large-scale datasets efficiently. ALFA could also be applied to other imaging modalities and other stages across the life course.

  3. Patient-adapted reconstruction and acquisition dynamic imaging method (PARADIGM) for MRI

    International Nuclear Information System (INIS)

    Aggarwal, Nitin; Bresler, Yoram

    2008-01-01

    Dynamic magnetic resonance imaging (MRI) is a challenging problem because the MR data acquisition is often not fast enough to meet the combined spatial and temporal Nyquist sampling rate requirements. Current approaches to this problem include hardware-based acceleration of the acquisition, and model-based image reconstruction techniques. In this paper we propose an alternative approach, called PARADIGM, which adapts both the acquisition and reconstruction to the spatio-temporal characteristics of the imaged object. The approach is based on time-sequential sampling theory, addressing the problem of acquiring a spatio-temporal signal under the constraint that only a limited amount of data can be acquired at a time instant. PARADIGM identifies a model class for the particular imaged object using a scout MR scan or auxiliary data. This object-adapted model is then used to optimize MR data acquisition, such that the imaging constraints are met, acquisition speed requirements are minimized, essentially perfect reconstruction of any object in the model class is guaranteed, and the inverse problem of reconstructing the dynamic object has a condition number of one. We describe spatio-temporal object models for various dynamic imaging applications including cardiac imaging. We present the theory underlying PARADIGM and analyze its performance theoretically and numerically. We also propose a practical MR imaging scheme for 2D dynamic cardiac imaging based on the theory. For this application, PARADIGM is predicted to provide a 10–25 × acceleration compared to the optimal non-adaptive scheme. Finally we present generalized optimality criteria and extend the scheme to dynamic imaging with three spatial dimensions

  4. Orientation of Al3Ti platelets in Al-Al3Ti functionally graded material manufactured by centrifugal method

    International Nuclear Information System (INIS)

    Watanabe, Y.; Fukui, Y.

    1997-01-01

    Al-Al 3 Ti functionally graded materials (FGMs) were manufactured by the centrifugal method with a commercial ingot of Al-5 mass% Ti master alloy. The alloy was melted at a liquid/solid coexisting temperature, at which Al 3 Ti remains as a solid, and then it was cast into a thick-walled ring. It was found that the Al-Al 3 Ti functionally graded material can be successfully fabricated by the centrifugal method. It was also found that the volume fraction of the Al 3 Ti can be increased by repetition of the centrifugal method. Since the shape of Al 3 Ti particles in a commercial alloy ingot is that of a platelet, the Al 3 Ti particles are arranged with their platelet planes nearly perpendicular to the radial direction. The orientation effects become stronger when the G number becomes larger. Although the final centrifugal casting was conducted under a very large centrifugal force for the specimen cast three times, the orientation effects were weaker than those in the specimen cast one time. From these observations, it is concluded that the origin of orientation of Al 3 Ti platelets can be attributed to the angular velocity gradient of the melt along the radial direction produced by the difference in the viscosity. (orig.)

  5. MRI in sarcoglycanopathies

    DEFF Research Database (Denmark)

    Tasca, Giorgio; Monforte, Mauro; Díaz-Manera, Jordi

    2018-01-01

    OBJECTIVES: To characterise the pattern and spectrum of involvement on muscle MRI in a large cohort of patients with sarcoglycanopathies, which are limb-girdle muscular dystrophies (LGMD2C-2F) caused by mutations in one of the four genes coding for muscle sarcoglycans. METHODS: Lower limb MRI sca...

  6. MRI of the Chest

    Medline Plus

    Full Text Available ... structure of an organ and how it is working. MRI enables the discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used in MRI exams is less likely to produce an allergic reaction than the ...

  7. International lessons in new methods for grading and integrating cost effectiveness evidence into clinical practice guidelines.

    Science.gov (United States)

    Antioch, Kathryn M; Drummond, Michael F; Niessen, Louis W; Vondeling, Hindrik

    2017-01-01

    Economic evidence is influential in health technology assessment world-wide. Clinical Practice Guidelines (CPG) can enable economists to include economic information on health care provision. Application of economic evidence in CPGs, and its integration into clinical practice and national decision making is hampered by objections from professions, paucity of economic evidence or lack of policy commitment. The use of state-of-art economic methodologies will improve this. Economic evidence can be graded by 'checklists' to establish the best evidence for decision making given methodological rigor. New economic evaluation checklists, Multi-Criteria Decision Analyses (MCDA) and other decision criteria enable health economists to impact on decision making world-wide. We analyse the methodologies for integrating economic evidence into CPG agencies globally, including the Agency of Health Research and Quality (AHRQ) in the USA, National Health and Medical Research Council (NHMRC) and Australian political reforms. The Guidelines and Economists Network International (GENI) Board members from Australia, UK, Canada and Denmark presented the findings at the conference of the International Health Economists Association (IHEA) and we report conclusions and developments since. The Consolidated Guidelines for the Reporting of Economic Evaluations (CHEERS) 24 item check list can be used by AHRQ, NHMRC, other CPG and health organisations, in conjunction with the Drummond ten-point check list and a questionnaire that scores that checklist for grading studies, when assessing economic evidence. Cost-effectiveness Analysis (CEA) thresholds, opportunity cost and willingness-to-pay (WTP) are crucial issues for decision rules in CEA generally, including end-of-life therapies. Limitations of inter-rater reliability in checklists can be addressed by including more than one assessor to reach a consensus, especially when impacting on treatment decisions. We identify priority areas to generate

  8. Beginning German in Grade Three: MLA Teacher's Guide. A Course of Study Including Methods, Materials, and Aids for Teaching Conversational German to Third-Grade Children.

    Science.gov (United States)

    Wittman, Nora E.; And Others

    This guide is planned to help the FLES teacher develop pleasurable language learning experiences in spoken German for children at the third-grade level. Experiences included in this guide present German in life situations, as well as insight into German culture. The guide offers suggestions for classroom procedures, and detailed directions are…

  9. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

  10. MRI and neurological findings in patients with spinal metastases

    International Nuclear Information System (INIS)

    Switlyk, M.D.; Hole, K.H.; Knutstad, K.; Skjeldal, S.; Zaikova, O.; Hald, J.K.; Seierstad, T.

    2012-01-01

    Background. Magnetic resonance imaging (MRI) is the recommended primary investigation method for metastatic spinal cord compression (MSCC). Initiating treatment before the development of motor deficits is essential to preserve neurological function. However, the relationship between MRI-assessed grades of spinal metastatic disease and neurological status has not been widely investigated. Purpose. To analyze the association between neurological function and MRI-based assessment of the extent of spinal metastases using two different grading systems. Material and Methods. A total of 284 patients admitted to our institution for initial radiotherapy or surgery for symptomatic spinal metastases were included in the study. Motor and sensory deficits were categorized according to the Frankel classification system. Pre-treatment MRI evaluations of the entire spine were scored for the extent of spinal metastases, presence and severity of spinal cord compression, and nerve root compression. Two MRI-based scales were used to evaluate the degree of cord compression and spinal canal narrowing and relate these findings to neurological function. Results. Of the patients included in the study, 28 were non-ambulatory, 49 were ambulatory with minor motor deficits, and 207 had normal motor function. Spinal cord compression was present in all patients with Frankel scores of B or C, 23 of 35 patients with a Frankel score of D (66%), and 48 of 152 patients with a Frankel score of E (32%). The percentage of patients with severe spinal canal narrowing increased with increasing Frankel grades. The grading according to the scales showed a significant association with the symptoms according to the Frankel scale (P < 0.001). Conclusion. In patients with neurological dysfunction, the presence and severity of impairment was associated with the epidural tumor burden. A significant number of patients had radiological spinal cord compression and normal motor function (occult MSCC)

  11. International lessons in new methods for grading and integrating cost effectiveness evidence into clinical practice guidelines

    DEFF Research Database (Denmark)

    Antioch, Kathryn M; Drummond, Michael F; Niessen, Louis W

    2017-01-01

    Economic evidence is influential in health technology assessment world-wide. Clinical Practice Guidelines (CPG) can enable economists to include economic information on health care provision. Application of economic evidence in CPGs, and its integration into clinical practice and national decisio......-of-life, budget impact, cost-effective ratios, net benefits and disparities in access and outcomes. Priority setting remains essential and trade-off decisions between policy criteria can be based on MCDA, both in evidence based clinical medicine and in health planning....... that scores that checklist for grading studies, when assessing economic evidence. Cost-effectiveness Analysis (CEA) thresholds, opportunity cost and willingness-to-pay (WTP) are crucial issues for decision rules in CEA generally, including end-of-life therapies. Limitations of inter-rater reliability......, logistics, innovation price, price sensitivity, substitutes and complements, WTP, absenteeism and presentism. Supply issues may include economies of scale, efficiency changes, and return on investment. Involved equity and efficiency measures may include cost-of-illness, disease burden, quality...

  12. Method for Forming Fiber Reinforced Composite Bodies with Graded Composition and Stress Zones

    Science.gov (United States)

    Singh, Mrityunjay (Inventor); Levine, Stanley R. (Inventor); Smialek, James A. (Inventor)

    1999-01-01

    A near-net, complex shaped ceramic fiber reinforced silicon carbide based composite bodies with graded compositions and stress zones is disclosed. To provide the composite a fiber preform is first fabricated and an interphase is applied by chemical vapor infiltration, sol-gel or polymer processes. This first body is further infiltrated with a polymer mixture containing carbon, and/or silicon carbide, and additional oxide, carbide, or nitride phases forming a second body. One side of the second body is spray coated or infiltrated with slurries containing high thermal expansion and oxidation resistant. crack sealant phases and the other side of this second body is coated with low expansion phase materials to form a third body. This third body consisting of porous carbonaceous matrix surrounding the previously applied interphase materials, is then infiltrated with molten silicon or molten silicon-refractory metal alloys to form a fourth body. The resulting fourth body comprises dense composites consisting of fibers with the desired interphase which are surrounded by silicon carbide and other second phases materials at the outer and inner surfaces comprising material of silicon, germanium, refractory metal suicides, borides, carbides, oxides, and combinations thereof The resulting composite fourth body has different compositional patterns from one side to the other.

  13. ADvanced IMage Algebra (ADIMA): a novel method for depicting multiple sclerosis lesion heterogeneity, as demonstrated by quantitative MRI.

    Science.gov (United States)

    Yiannakas, Marios C; Tozer, Daniel J; Schmierer, Klaus; Chard, Declan T; Anderson, Valerie M; Altmann, Daniel R; Miller, David H; Wheeler-Kingshott, Claudia A M

    2013-05-01

    There are modest correlations between multiple sclerosis (MS) disability and white matter lesion (WML) volumes, as measured by T2-weighted (T2w) magnetic resonance imaging (MRI) scans (T2-WML). This may partly reflect pathological heterogeneity in WMLs, which is not apparent on T2w scans. To determine if ADvanced IMage Algebra (ADIMA), a novel MRI post-processing method, can reveal WML heterogeneity from proton-density weighted (PDw) and T2w images. We obtained conventional PDw and T2w images from 10 patients with relapsing-remitting MS (RRMS) and ADIMA images were calculated from these. We classified all WML into bright (ADIMA-b) and dark (ADIMA-d) sub-regions, which were segmented. We obtained conventional T2-WML and T1-WML volumes for comparison, as well as the following quantitative magnetic resonance parameters: magnetisation transfer ratio (MTR), T1 and T2. Also, we assessed the reproducibility of the segmentation for ADIMA-b, ADIMA-d and T2-WML. Our study's ADIMA-derived volumes correlated with conventional lesion volumes (p < 0.05). ADIMA-b exhibited higher T1 and T2, and lower MTR than the T2-WML (p < 0.001). Despite the similarity in T1 values between ADIMA-b and T1-WML, these regions were only partly overlapping with each other. ADIMA-d exhibited quantitative characteristics similar to T2-WML; however, they were only partly overlapping. Mean intra- and inter-observer coefficients of variation for ADIMA-b, ADIMA-d and T2-WML volumes were all < 6 % and < 10 %, respectively. ADIMA enabled the simple classification of WML into two groups having different quantitative magnetic resonance properties, which can be reproducibly distinguished.

  14. A fast alignment method for breast MRI follow-up studies using automated breast segmentation and current-prior registration

    Science.gov (United States)

    Wang, Lei; Strehlow, Jan; Rühaak, Jan; Weiler, Florian; Diez, Yago; Gubern-Merida, Albert; Diekmann, Susanne; Laue, Hendrik; Hahn, Horst K.

    2015-03-01

    In breast cancer screening for high-risk women, follow-up magnetic resonance images (MRI) are acquired with a time interval ranging from several months up to a few years. Prior MRI studies may provide additional clinical value when examining the current one and thus have the potential to increase sensitivity and specificity of screening. To build a spatial correlation between suspicious findings in both current and prior studies, a reliable alignment method between follow-up studies is desirable. However, long time interval, different scanners and imaging protocols, and varying breast compression can result in a large deformation, which challenges the registration process. In this work, we present a fast and robust spatial alignment framework, which combines automated breast segmentation and current-prior registration techniques in a multi-level fashion. First, fully automatic breast segmentation is applied to extract the breast masks that are used to obtain an initial affine transform. Then, a non-rigid registration algorithm using normalized gradient fields as similarity measure together with curvature regularization is applied. A total of 29 subjects and 58 breast MR images were collected for performance assessment. To evaluate the global registration accuracy, the volume overlap and boundary surface distance metrics are calculated, resulting in an average Dice Similarity Coefficient (DSC) of 0.96 and root mean square distance (RMSD) of 1.64 mm. In addition, to measure local registration accuracy, for each subject a radiologist annotated 10 pairs of markers in the current and prior studies representing corresponding anatomical locations. The average distance error of marker pairs dropped from 67.37 mm to 10.86 mm after applying registration.

  15. A methodology for generating normal and pathological brain perfusion SPECT images for evaluation of MRI/SPECT fusion methods: application in epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Grova, C [Laboratoire IDM, Faculte de Medecine, Universite de Rennes 1, Rennes (France); Jannin, P [Laboratoire IDM, Faculte de Medecine, Universite de Rennes 1, Rennes (France); Biraben, A [Laboratoire IDM, Faculte de Medecine, Universite de Rennes 1, Rennes (France); Buvat, I [INSERM U494, CHU Pitie Salpetriere, Paris (France); Benali, H [INSERM U494, CHU Pitie Salpetriere, Paris (France); Bernard, A M [Service de Medecine Nucleaire, Centre Eugene Marquis, Rennes (France); Scarabin, J M [Laboratoire IDM, Faculte de Medecine, Universite de Rennes 1, Rennes (France); Gibaud, B [Laboratoire IDM, Faculte de Medecine, Universite de Rennes 1, Rennes (France)

    2003-12-21

    Quantitative evaluation of brain MRI/SPECT fusion methods for normal and in particular pathological datasets is difficult, due to the frequent lack of relevant ground truth. We propose a methodology to generate MRI and SPECT datasets dedicated to the evaluation of MRI/SPECT fusion methods and illustrate the method when dealing with ictal SPECT. The method consists in generating normal or pathological SPECT data perfectly aligned with a high-resolution 3D T1-weighted MRI using realistic Monte Carlo simulations that closely reproduce the response of a SPECT imaging system. Anatomical input data for the SPECT simulations are obtained from this 3D T1-weighted MRI, while functional input data result from an inter-individual analysis of anatomically standardized SPECT data. The method makes it possible to control the 'brain perfusion' function by proposing a theoretical model of brain perfusion from measurements performed on real SPECT images. Our method provides an absolute gold standard for assessing MRI/SPECT registration method accuracy since, by construction, the SPECT data are perfectly registered with the MRI data. The proposed methodology has been applied to create a theoretical model of normal brain perfusion and ictal brain perfusion characteristic of mesial temporal lobe epilepsy. To approach realistic and unbiased perfusion models, real SPECT data were corrected for uniform attenuation, scatter and partial volume effect. An anatomic standardization was used to account for anatomic variability between subjects. Realistic simulations of normal and ictal SPECT deduced from these perfusion models are presented. The comparison of real and simulated SPECT images showed relative differences in regional activity concentration of less than 20% in most anatomical structures, for both normal and ictal data, suggesting realistic models of perfusion distributions for evaluation purposes. Inter-hemispheric asymmetry coefficients measured on simulated data were

  16. Computation of mode eigenfunctions in graded-index optical fibers by the propagating beam method

    International Nuclear Information System (INIS)

    Feit, M.D.; Fleck, J.A. Jr.

    1980-01-01

    The propagating beam method utilizes discrete Fourier transforms for generating configuration-space solutions to optical waveguide problems without reference to modes. The propagating beam method can also give a complete description of the field in terms of modes by a Fourier analysis with respect to axial distance of the computed fields. Earlier work dealt with the accurate determination of mode propagation constants and group delays. In this paper the method is extended to the computation of mode eigenfunctions. The method is efficient, allowing generation of a large number of eigenfunctions from a single propagation run. Computations for parabolic-index profiles show excellent agreement between analytic and numerically generated eigenfunctions

  17. Mobius syndrome: MRI features

    International Nuclear Information System (INIS)

    Markarian, Maria F.; Villarroel, Gonzalo M.; Nagel, Jorge R.

    2003-01-01

    Purpose: Mobius Syndrome or congenital facial diplegia is associated with paralysis of the lateral gaze movements. This syndrome may include other cranial nerve palsies and be associated to musculoskeletal anomalies. Our objective is to show the MRI findings in Mobius Syndrome. Material and methods: MRI study was performed in 3 patients with clinic diagnosis of Mobius Syndrome. RMI (1.5T); exams included axial FSE (T1 and T2), FLAIR, SE/EPI, GRE/20, sagittal FSE T2 , coronal T1, diffusion, angio MRI and Spectroscopy sequences. Results: The common features of this syndrome found in MRI were: depression or straightening of the floor of the fourth ventricle, brainstem anteroposterior diameter diminution, morphologic alteration of the pons and medulla oblongata and of the hypoglossal nuclei as well as severe micrognathia. Conclusion: The morphologic alterations of Mobius Syndrome can be clearly identified by MRI; this method has proved to be a useful diagnostic examination. (author)

  18. A semi-automatic method to determine electrode positions and labels from gel artifacts in EEG/fMRI-studies

    NARCIS (Netherlands)

    de Munck, J.C.; van Houdt, P.J.; Verdaasdonk, R.; Ossenblok, P.P.W.

    2012-01-01

    The analysis of simultaneous EEG and fMRI data is generally based on the extraction of regressors of interest from the EEG, which are correlated to the fMRI data in a general linear model setting. In more advanced approaches, the spatial information of EEG is also exploited by assuming underlying

  19. Chest MRI

    Science.gov (United States)

    ... resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI Patient Instructions ... Gotway MB, Panse PM, Gruden JF, Elicker BM. Thoracic radiology. In: Broaddus VC, Mason RJ, Ernst JD, et ...

  20. Integrating 6th Grade Geometry Standards into a Waldorf Methods Charter School

    Science.gov (United States)

    Watterson, Ilie Alma

    2006-01-01

    Many Waldorf methods charter schools are opening up in California today. They are publicly funded schools bringing Waldorf methods into public education. In today's political climate all public schools must pass the state's bar of academic success measured by their Adequate Yearly Progress (AYP). Because these scores are based largely on…

  1. Evaluation of the Usefulness of the MRI Jelly Method for Diagnosing Complete Cul-de-Sac Obliteration

    Directory of Open Access Journals (Sweden)

    Iwaho Kikuchi

    2014-01-01

    Full Text Available Objective. We conducted a single-center study to evaluate the usefulness of the magnetic resonance (MR imaging jelly method for diagnosing endometriosis-associated adhesions in the Pouch of Douglas. Methods. Thirty women with menstrual pain, dyspareunia, and chronic pelvic pain were enrolled in the study. All had been scheduled for laparoscopic surgery on the basis of pelvic and/or ultrasonographic (US evaluation. All underwent MR imaging both with and without application of US jelly to the vagina and rectum. The images were compared and analyzed postsurgically in a random and blinded fashion by a radiology specialist and a radiology fellow. The radiologists’ interpretations of the images were compared to the surgical findings recorded on DVDs. Results. Adhesions in the Pouch of Douglas were found in 21 patients. The sensitivity and specificity of MR imaging without jelly administration were 85.7% and 55.6%, respectively, for the specialist and 81.0% and 55.6%, respectively, for the fellow; with jelly administration, values were 95.2% and 88.9% for the specialist and 90.5% and 66.7% for the fellow. Opacity produced by the jelly increased the sensitivity and specificity for both radiologists. Conclusion. The MRI jelly method is a potentially useful, beneficial, and simple approach for diagnosing Pouch of Douglas adhesions.

  2. In vivo noninvasive thermometry for hyperthermia applications using the MRI-based proton-resonance-frequency method

    Energy Technology Data Exchange (ETDEWEB)

    De Poorter, J; De Deene, Y; Achten, E [Ghent University (Belgium). Dept. of Magnetic Resonance; De Wagter, C [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; Thomsen, C [Hvidovre Univ. (Denmark); Staahlberg, F [Lund Univ. (Sweden). Dept. of Radiation Physics

    1995-12-01

    The lack of noninvasive temperature monitoring is seriously limiting hyperthermia treatment of deep-seated tumors. MRI methods exploit the temperature dependence of a physical property whose spatial distribution can be visualized. The Proton Resonance Frequency (PRF) as physical property was examined because phantom studies prove the high accuracy that can be obtained using this parameter. Thermal experiments were performed in human lower legs. The results show that in muscle tissue the three-dimensional temperature distribution can be evaluated with a mean spatial distribution of 2 millimetres, a temporal resolution of 2 minutes and an accuracy of about 1 degree Celsius. However, it is not possible to retrieve the temperature distribution in fat tissue using the PRF-method due to the predominance of susceptibility effects in fat. The susceptibility effects are a consequence of the temperature dependence of the susceptibility constants. Experimental data on these dependencies were obtained and the magnitude of these effects was modelled for some specific configurations. The susceptibility effects in muscle tissue can be neglected when precautions are made. The PRF method is an attractive tool to study time-varying temperature changes in muscle tissue.

  3. In vivo noninvasive thermometry for hyperthermia applications using the MRI-based proton-resonance-frequency method

    International Nuclear Information System (INIS)

    De Poorter, J.; De Deene, Y.; Achten, E.; Staahlberg, F.

    1995-01-01

    The lack of noninvasive temperature monitoring is seriously limiting hyperthermia treatment of deep-seated tumors. MRI methods exploit the temperature dependence of a physical property whose spatial distribution can be visualized. The Proton Resonance Frequency (PRF) as physical property was examined because phantom studies prove the high accuracy that can be obtained using this parameter. Thermal experiments were performed in human lower legs. The results show that in muscle tissue the three-dimensional temperature distribution can be evaluated with a mean spatial distribution of 2 millimetres, a temporal resolution of 2 minutes and an accuracy of about 1 degree Celsius. However, it is not possible to retrieve the temperature distribution in fat tissue using the PRF-method due to the predominance of susceptibility effects in fat. The susceptibility effects are a consequence of the temperature dependence of the susceptibility constants. Experimental data on these dependencies were obtained and the magnitude of these effects was modelled for some specific configurations. The susceptibility effects in muscle tissue can be neglected when precautions are made. The PRF method is an attractive tool to study time-varying temperature changes in muscle tissue

  4. Evaluating fMRI methods for assessing hemispheric language dominance in healthy subjects.

    Science.gov (United States)

    Baciu, Monica; Juphard, Alexandra; Cousin, Emilie; Bas, Jean François Le

    2005-08-01

    We evaluated two methods for quantifying the hemispheric language dominance in healthy subjects, by using a rhyme detection (deciding whether couple of words rhyme) and a word fluency (generating words starting with a given letter) task. One of methods called "flip method" (FM) was based on the direct statistical comparison between hemispheres' activity. The second one, the classical lateralization indices method (LIM), was based on calculating lateralization indices by taking into account the number of activated pixels within hemispheres. The main difference between methods is the statistical assessment of the inter-hemispheric difference: while FM shows if the difference between hemispheres' activity is statistically significant, LIM shows only that if there is a difference between hemispheres. The robustness of LIM and FM was assessed by calculating correlation coefficients between LIs obtained with each of these methods and manual lateralization indices MLI obtained with Edinburgh inventory. Our results showed significant correlation between LIs provided by each method and the MIL, suggesting that both methods are robust for quantifying hemispheric dominance for language in healthy subjects. In the present study we also evaluated the effect of spatial normalization, smoothing and "clustering" (NSC) on the intra-hemispheric location of activated regions and inter-hemispheric asymmetry of the activation. Our results have shown that NSC did not affect the hemispheric specialization but increased the value of the inter-hemispheric difference.

  5. Evaluating fMRI methods for assessing hemispheric language dominance in healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Baciu, Monica [Laboratoire de Psychologie et NeuroCognition, UMR 5105 CNRS, Universite Pierre Mendes-France, F38040 Grenoble Cedex 09 (France)]. E-mail: mbaciu@upmf-grenoble.fr; Juphard, Alexandra [Laboratoire de Psychologie et NeuroCognition, UMR 5105 CNRS, Universite Pierre Mendes-France, F38040 Grenoble Cedex 09 (France); Cousin, Emilie [Laboratoire de Psychologie et NeuroCognition, UMR 5105 CNRS, Universite Pierre Mendes-France, F38040 Grenoble Cedex 09 (France); Bas, Jean Francois Le [Unite IRM, CHU Grenoble (France)

    2005-08-01

    We evaluated two methods for quantifying the hemispheric language dominance in healthy subjects, by using a rhyme detection (deciding whether couple of words rhyme) and a word fluency (generating words starting with a given letter) task. One of methods called 'flip method' (FM) was based on the direct statistical comparison between hemispheres' activity. The second one, the classical lateralization indices method (LIM), was based on calculating lateralization indices by taking into account the number of activated pixels within hemispheres. The main difference between methods is the statistical assessment of the inter-hemispheric difference: while FM shows if the difference between hemispheres' activity is statistically significant, LIM shows only that if there is a difference between hemispheres. The robustness of LIM and FM was assessed by calculating correlation coefficients between LIs obtained with each of these methods and manual lateralization indices MLI obtained with Edinburgh inventory. Our results showed significant correlation between LIs provided by each method and the MIL, suggesting that both methods are robust for quantifying hemispheric dominance for language in healthy subjects. In the present study we also evaluated the effect of spatial normalization, smoothing and 'clustering' (NSC) on the intra-hemispheric location of activated regions and inter-hemispheric asymmetry of the activation. Our results have shown that NSC did not affect the hemispheric specialization but increased the value of the inter-hemispheric difference.

  6. Evaluating fMRI methods for assessing hemispheric language dominance in healthy subjects

    International Nuclear Information System (INIS)

    Baciu, Monica; Juphard, Alexandra; Cousin, Emilie; Bas, Jean Francois Le

    2005-01-01

    We evaluated two methods for quantifying the hemispheric language dominance in healthy subjects, by using a rhyme detection (deciding whether couple of words rhyme) and a word fluency (generating words starting with a given letter) task. One of methods called 'flip method' (FM) was based on the direct statistical comparison between hemispheres' activity. The second one, the classical lateralization indices method (LIM), was based on calculating lateralization indices by taking into account the number of activated pixels within hemispheres. The main difference between methods is the statistical assessment of the inter-hemispheric difference: while FM shows if the difference between hemispheres' activity is statistically significant, LIM shows only that if there is a difference between hemispheres. The robustness of LIM and FM was assessed by calculating correlation coefficients between LIs obtained with each of these methods and manual lateralization indices MLI obtained with Edinburgh inventory. Our results showed significant correlation between LIs provided by each method and the MIL, suggesting that both methods are robust for quantifying hemispheric dominance for language in healthy subjects. In the present study we also evaluated the effect of spatial normalization, smoothing and 'clustering' (NSC) on the intra-hemispheric location of activated regions and inter-hemispheric asymmetry of the activation. Our results have shown that NSC did not affect the hemispheric specialization but increased the value of the inter-hemispheric difference

  7. Optimization of the reference region method for dual pharmacokinetic modeling using Gd-DTPA/MRI and (18) F-FDG/PET.

    Science.gov (United States)

    Poulin, Éric; Lebel, Réjean; Croteau, Étienne; Blanchette, Marie; Tremblay, Luc; Lecomte, Roger; Bentourkia, M'hamed; Lepage, Martin

    2015-02-01

    The combination of MRI and positron emission tomography (PET) offers new possibilities for the development of novel methodologies. In pharmacokinetic image analysis, the blood concentration of the imaging compound as a function of time, [i.e., the arterial input function (AIF)] is required for MRI and PET. In this study, we tested whether an AIF extracted from a reference region (RR) in MRI can be used as a surrogate for the manually sampled (18) F-FDG AIF for pharmacokinetic modeling. An MRI contrast agent, gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and a radiotracer, (18) F-fluorodeoxyglucose ((18) F-FDG), were simultaneously injected in a F98 glioblastoma rat model. A correction to the RR AIF for Gd-DTPA is proposed to adequately represent the manually sampled AIF. A previously published conversion method was applied to convert this AIF into a (18) F-FDG AIF. The tumor metabolic rate of glucose (TMRGlc) calculated with the manually sampled (18) F-FDG AIF, the (18) F-FDG AIF converted from the RR AIF and the (18) F-FDG AIF converted from the corrected RR AIF were found not statistically different (P>0.05). An AIF derived from an RR in MRI can be accurately converted into a (18) F-FDG AIF and used in PET pharmacokinetic modeling. © 2014 Wiley Periodicals, Inc.

  8. A comparison of three clustering methods for finding subgroups in MRI, SMS or clinical data

    DEFF Research Database (Denmark)

    Kent, Peter; Jensen, Rikke K; Kongsted, Alice

    2014-01-01

    ). There is a scarcity of head-to-head comparisons that can inform the choice of which clustering method might be suitable for particular clinical datasets and research questions. Therefore, the aim of this study was to perform a head-to-head comparison of three commonly available methods (SPSS TwoStep CA, Latent Gold...... LCA and SNOB LCA). METHODS: The performance of these three methods was compared: (i) quantitatively using the number of subgroups detected, the classification probability of individuals into subgroups, the reproducibility of results, and (ii) qualitatively using subjective judgments about each program...... classify individuals into those subgroups. CONCLUSIONS: Our subjective judgement was that Latent Gold offered the best balance of sensitivity to subgroups, ease of use and presentation of results with these datasets but we recognise that different clustering methods may suit other types of data...

  9. MRI of hip prostheses using single-point methods : in vitro studies towards the artifact-free imaging of individuals with metal implants

    NARCIS (Netherlands)

    Ramos Cabrer, P.; Duynhoven, van J.P.M.; Toorn, van der A.; Nicolaij, K.

    2004-01-01

    Use of magnetic resonance imaging (MRI) in individuals with orthopedic implants is limited because of the large distortions caused by metallic components. As a possible solution for this problem, we suggest the use of single-point imaging (SPI) methods, which are immune to the susceptibility

  10. Investigation on water status and distribution in broccoli and the effects of drying on water status using NMR and MRI methods

    NARCIS (Netherlands)

    Xu, Fangfang; Jin, Xin; Zhang, Lu; Chen, Xiao Dong

    2017-01-01

    Many quality attributes of food products are influenced by the water status and the microstructure. Low-field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) methods are applied to non-destructively monitor the water status and structure of food. The aim of this study is to

  11. Estimating the arterial input function from dynamic contrast-enhanced MRI data with compensation for flow enhancement (I): Theory, method, and phantom experiments

    NARCIS (Netherlands)

    van Schie, Jeroen J. N.; Lavini, Cristina; van Vliet, Lucas J.; Vos, Frans M.

    2017-01-01

    The arterial input function (AIF) represents the time-dependent arterial contrast agent (CA) concentration that is used in pharmacokinetic modeling. To develop a novel method for estimating the AIF from dynamic contrast-enhanced (DCE-) MRI data, while compensating for flow enhancement. Signal

  12. Histological Grading of Hepatocellular Carcinomas with Intravoxel Incoherent Motion Diffusion-weighted Imaging: Inconsistent Results Depending on the Fitting Method.

    Science.gov (United States)

    Ichikawa, Shintaro; Motosugi, Utaroh; Hernando, Diego; Morisaka, Hiroyuki; Enomoto, Nobuyuki; Matsuda, Masanori; Onishi, Hiroshi

    2018-04-10

    To compare the abilities of three intravoxel incoherent motion (IVIM) imaging approximation methods to discriminate the histological grade of hepatocellular carcinomas (HCCs). Fifty-eight patients (60 HCCs) underwent IVIM imaging with 11 b-values (0-1000 s/mm 2 ). Slow (D) and fast diffusion coefficients (D * ) and the perfusion fraction (f) were calculated for the HCCs using the mean signal intensities in regions of interest drawn by two radiologists. Three approximation methods were used. First, all three parameters were obtained simultaneously using non-linear fitting (method A). Second, D was obtained using linear fitting (b = 500 and 1000), followed by non-linear fitting for D * and f (method B). Third, D was obtained by linear fitting, f was obtained using the regression line intersection and signals at b = 0, and non-linear fitting was used for D * (method C). A receiver operating characteristic analysis was performed to reveal the abilities of these methods to distinguish poorly-differentiated from well-to-moderately-differentiated HCCs. Inter-reader agreements were assessed using intraclass correlation coefficients (ICCs). The measurements of D, D * , and f in methods B and C (Az-value, 0.658-0.881) had better discrimination abilities than did those in method A (Az-value, 0.527-0.607). The ICCs of D and f were good to excellent (0.639-0.835) with all methods. The ICCs of D * were moderate with methods B (0.580) and C (0.463) and good with method A (0.705). The IVIM parameters may vary depending on the fitting methods, and therefore, further technical refinement may be needed.

  13. Signal-to-noise ratio measurement in parallel MRI with subtraction mapping and consecutive methods

    International Nuclear Information System (INIS)

    Imai, Hiroshi; Miyati, Tosiaki; Ogura, Akio; Doi, Tsukasa; Tsuchihashi, Toshio; Machida, Yoshio; Kobayashi, Masato; Shimizu, Kouzou; Kitou, Yoshihiro

    2008-01-01

    When measuring the signal-to-noise ratio (SNR) of an image the used parallel magnetic resonance imaging, it was confirmed that there was a problem in the application of past SNR measurement. With the method of measuring the noise from the background signal, SNR with parallel imaging was higher than that without parallel imaging. In the subtraction method (NEMA standard), which sets a wide region of interest, the white noise was not evaluated correctly although SNR was close to the theoretical value. We proposed two techniques because SNR in parallel imaging was not uniform according to inhomogeneity of the coil sensitivity distribution and geometry factor. Using the first method (subtraction mapping), two images were scanned with identical parameters. The SNR in each pixel divided the running mean (7 by 7 pixels in neighborhood) by standard deviation/√2 in the same region of interest. Using the second (consecutive) method, more than fifty consecutive scans of the uniform phantom were obtained with identical scan parameters. Then the SNR was calculated from the ratio of mean signal intensity to the standard deviation in each pixel on a series of images. Moreover, geometry factors were calculated from SNRs with and without parallel imaging. The SNR and geometry factor using parallel imaging in the subtraction mapping method agreed with those of the consecutive method. Both methods make it possible to obtain a more detailed determination of SNR in parallel imaging and to calculate the geometry factor. (author)

  14. A Design Method for Graded Insulation of Transformers by Transient Electric Field Intensity Analysis

    OpenAIRE

    Yamashita, Hideo; Cingoski, Vlatko; Namera, Akihiro; Nakamae, Eihachiro; Kitamura, Hideo

    2000-01-01

    In this paper, a calculation method for transient electric field distribution inside a transformer impressed with voltage is proposed: The concentrated electric network for the transformer is constructed by dividing transformer windings into several blocks, and the transient voltage and electric field intensity distributions inside the transformer are calculated by using the axisymmetrical finite element method. Moreover, an animated display of the distributions is realized: The visualization...

  15. A Dictionary Learning Method with Total Generalized Variation for MRI Reconstruction.

    Science.gov (United States)

    Lu, Hongyang; Wei, Jingbo; Liu, Qiegen; Wang, Yuhao; Deng, Xiaohua

    2016-01-01

    Reconstructing images from their noisy and incomplete measurements is always a challenge especially for medical MR image with important details and features. This work proposes a novel dictionary learning model that integrates two sparse regularization methods: the total generalized variation (TGV) approach and adaptive dictionary learning (DL). In the proposed method, the TGV selectively regularizes different image regions at different levels to avoid oil painting artifacts largely. At the same time, the dictionary learning adaptively represents the image features sparsely and effectively recovers details of images. The proposed model is solved by variable splitting technique and the alternating direction method of multiplier. Extensive simulation experimental results demonstrate that the proposed method consistently recovers MR images efficiently and outperforms the current state-of-the-art approaches in terms of higher PSNR and lower HFEN values.

  16. A Dictionary Learning Method with Total Generalized Variation for MRI Reconstruction

    Directory of Open Access Journals (Sweden)

    Hongyang Lu

    2016-01-01

    Full Text Available Reconstructing images from their noisy and incomplete measurements is always a challenge especially for medical MR image with important details and features. This work proposes a novel dictionary learning model that integrates two sparse regularization methods: the total generalized variation (TGV approach and adaptive dictionary learning (DL. In the proposed method, the TGV selectively regularizes different image regions at different levels to avoid oil painting artifacts largely. At the same time, the dictionary learning adaptively represents the image features sparsely and effectively recovers details of images. The proposed model is solved by variable splitting technique and the alternating direction method of multiplier. Extensive simulation experimental results demonstrate that the proposed method consistently recovers MR images efficiently and outperforms the current state-of-the-art approaches in terms of higher PSNR and lower HFEN values.

  17. The results of STEM education methods in physics at the 11th grade level: Light and visual equipment lesson

    Science.gov (United States)

    Tungsombatsanti, A.; Ponkham, K.; Somtoa, T.

    2018-01-01

    This research aimed to: 1) To evaluate the efficiency of the process and the efficiency of the results (E1 / E2) of the innovative instructional lesson plan in the form of the STEM Education method in the field of physics of secondary students at the 10th grade level in physics class to determine the efficiency of the STEM based on criteria of the 70/70 standard level. 2) To study students' critical thinking skills of secondary students at the 11th grade level, and assessing skill in criteria 80 percentage 3) To compare learning achievements between students' pre-post testing after taught in STEM Education 4) To evaluate Student' Satisfaction after using STEM Education teaching by using mean compare to 5 points Likert Scale. The participant used were 40 students from grade 11 at Borabu School, Borabu District, Mahasarakham Province, semester 2, Academic year 2016. Tools used in this study consist of: 1) STEM Education plan about the force and laws of motion for grade 11 students of 1 schemes with total of 15 hours, 2) The test of critical think skills with essay type in amount of 30 items, 3) achievement test on Light and visual equipment with multiple-choice of 4 options of 30 items, 4) satisfaction learning with 5 Rating Scale of 16 items. The statistics used in data analysis were percentage, mean, standard deviation, and t-test (Dependent). The results showed that 1) The results of these findings revealed that the efficiency of the STEM based on criteria indicate that are higher than the standard level of the 70/70 at 71.51/75 2) Student has critical thinking scores that are higher than criteria 80 percentage as amount is 26 people. 3) Statistically significant of students' learning achievements to their later outcomes were differentiated between pretest and posttest at the .05 level, evidently. 4) The student' level of satisfaction toward the learning by using STEM Education plan was at a good level (X ¯ = 4.33, S.D = 0.64).

  18. Spectral collocation method with a flexible angular discretization scheme for radiative transfer in multi-layer graded index medium

    Science.gov (United States)

    Wei, Linyang; Qi, Hong; Sun, Jianping; Ren, Yatao; Ruan, Liming

    2017-05-01

    The spectral collocation method (SCM) is employed to solve the radiative transfer in multi-layer semitransparent medium with graded index. A new flexible angular discretization scheme is employed to discretize the solid angle domain freely to overcome the limit of the number of discrete radiative direction when adopting traditional SN discrete ordinate scheme. Three radial basis function interpolation approaches, named as multi-quadric (MQ), inverse multi-quadric (IMQ) and inverse quadratic (IQ) interpolation, are employed to couple the radiative intensity at the interface between two adjacent layers and numerical experiments show that MQ interpolation has the highest accuracy and best stability. Variable radiative transfer problems in double-layer semitransparent media with different thermophysical properties are investigated and the influence of these thermophysical properties on the radiative transfer procedure in double-layer semitransparent media is also analyzed. All the simulated results show that the present SCM with the new angular discretization scheme can predict the radiative transfer in multi-layer semitransparent medium with graded index efficiently and accurately.

  19. A Mixed-Methods Study on the Impact of Socratic Seminars on Eighth Grade Students' Comprehension of Science Texts

    Science.gov (United States)

    Roncke, Nancy

    This formative, convergent-mixed methods research study investigated the impact of Socratic Seminars on eighth grade science students' independent comprehension of science texts. The study also highlighted how eighth grade students of varying reading abilities interacted with and comprehended science texts differently during and after the use of Socratic Seminars. In order to document any changes in the students' overall comprehension of science texts, this study compared the experimental and control groups' pre- and post-test performances on the Content Area Reading Assessment (Leslie & Caldwell, 2014) and self-perception surveys on students' scientific reading engagement. Student think-alouds and interviews also captured the students' evolving understandings of the science texts. At the conclusion of this sixteen-week study, the achievement gap between the experimental and control group was closed in five of the seven categories on the Content Area Reading Assessment, including supporting an inference with textual evidence, determining central ideas, explaining why or how, determining word meaning, and summarizing a science text. Students' self-perception surveys were more positive regarding reading science texts after the Socratic Seminars. Finally, the student think-alouds revealed that some students moved from a literal interpretation of the science texts to inquiries that questioned the text and world events.

  20. Toward implementing an MRI-based PET attenuation-correction method for neurologic studies on the MR-PET brain prototype.

    Science.gov (United States)

    Catana, Ciprian; van der Kouwe, Andre; Benner, Thomas; Michel, Christian J; Hamm, Michael; Fenchel, Matthias; Fischl, Bruce; Rosen, Bruce; Schmand, Matthias; Sorensen, A Gregory

    2010-09-01

    Several factors have to be considered for implementing an accurate attenuation-correction (AC) method in a combined MR-PET scanner. In this work, some of these challenges were investigated, and an AC method based entirely on the MRI data obtained with a single dedicated sequence was developed and used for neurologic studies performed with the MR-PET human brain scanner prototype. The focus was on the problem of bone-air segmentation, selection of the linear attenuation coefficient for bone, and positioning of the radiofrequency coil. The impact of these factors on PET data quantification was studied in simulations and experimental measurements performed on the combined MR-PET scanner. A novel dual-echo ultrashort echo time (DUTE) MRI sequence was proposed for head imaging. Simultaneous MR-PET data were acquired, and the PET images reconstructed using the proposed DUTE MRI-based AC method were compared with the PET images that had been reconstructed using a CT-based AC method. Our data suggest that incorrectly accounting for the bone tissue attenuation can lead to large underestimations (>20%) of the radiotracer concentration in the cortex. Assigning a linear attenuation coefficient of 0.143 or 0.151 cm(-1) to bone tissue appears to give the best trade-off between bias and variability in the resulting images. Not identifying the internal air cavities introduces large overestimations (>20%) in adjacent structures. On the basis of these results, the segmented CT AC method was established as the silver standard for the segmented MRI-based AC method. For an integrated MR-PET scanner, in particular, ignoring the radiofrequency coil attenuation can cause large underestimations (i.e., MRI- and CT-based AC methods compare favorably in most of

  1. Cross-Grade Analysis of Chinese Students' English Learning Motivation: A Mixed-Methods Study

    Science.gov (United States)

    Zhang, Qian-Mei; Kim, Tae-Young

    2013-01-01

    This mixed-methods study investigated the changes in Chinese students' motivation to learn English from elementary to high school and explored the reasons for these changes at different school levels. A motivational questionnaire was designed and administered to 3,777 elementary, junior high, and high school students, and follow-up interviews were…

  2. Noninvasive MRI thermometry with the proton resonance frequency (PRF) method: in vivo results in human muscle

    DEFF Research Database (Denmark)

    De Poorter, J; De Wagter, C; De Deene, Y

    1995-01-01

    The noninvasive thermometry method is based on the temperature dependence of the proton resonance frequency (PRF). High-quality temperature images can be obtained from phase information of standard gradient-echo sequences with an accuracy of 0.2 degrees C in phantoms. This work was focused on the...

  3. A primal–dual hybrid gradient method for nonlinear operators with applications to MRI

    KAUST Repository

    Valkonen, Tuomo

    2014-01-01

    generalized variation priors. For such problems, we show that our general local convergence result holds when the noise level of the data f is low, and the regularization parameter α is correspondingly small. We verify the numerical performance of the method

  4. MRI of symptomatic shoulders

    International Nuclear Information System (INIS)

    Kikukawa, Kenshi; Segata, Tateki; Kunitake, Katsuhiko; Morisawa, Keizo; Harada, Masataka; Hirano, Mako

    2004-01-01

    The purpose of this study was to determine the prevalence of cuff tear and acromioclavicular joint (ACJ) osteoarthrosis by magnetic resonance imaging (MRI) evaluation in symptomatic shoulders. MRI was performed on 124 shoulders in 115 patients whose age ranged from 16 to 83 years (average: 58.0 years). There were 74 men (79 shoulders) and 41 women (45 shoulders). The patients were divided into three groups according to age; A group (10 shoulders: 16-29 years), B group (43 shoulders: 30-59 years), and C group (71 shoulders: 60-83 years). Rotator cuff tears and ACJ osteoarthrosis were graded on scales 0 to 3 (normal, increased signal intensity, incomplete, complete), and 1 to 4 (none, mild, moderate, severe), respectively. There was a significant difference in the severity of the cuff tears and the ACJ osteoarthrosis with respect to age. Twenty percent of the shoulders were graded incomplete or complete cuff tears in group A, 88% in group B, and 93% in group C. No shoulders were graded moderate or severe ACJ changes in group A, 63% in group B, and 93% in group C. There was a definite correlation between the cuff tears and ACJ osteoarthrosis. MRI of the symptomatic shoulders indicated well correlation between the rotator cuff tears and ACJ osteoarthrosis. (author)

  5. Segmentation of Brain MRI Using SOM-FCM-Based Method and 3D Statistical Descriptors

    Directory of Open Access Journals (Sweden)

    Andrés Ortiz

    2013-01-01

    Full Text Available Current medical imaging systems provide excellent spatial resolution, high tissue contrast, and up to 65535 intensity levels. Thus, image processing techniques which aim to exploit the information contained in the images are necessary for using these images in computer-aided diagnosis (CAD systems. Image segmentation may be defined as the process of parcelling the image to delimit different neuroanatomical tissues present on the brain. In this paper we propose a segmentation technique using 3D statistical features extracted from the volume image. In addition, the presented method is based on unsupervised vector quantization and fuzzy clustering techniques and does not use any a priori information. The resulting fuzzy segmentation method addresses the problem of partial volume effect (PVE and has been assessed using real brain images from the Internet Brain Image Repository (IBSR.

  6. Clinical evaluation of pulmonary perfusion MRI using FAIR (flow-sensitive alternating inversion recovery)-HASTE (Half-Fourier Single-Shot TurboSE) method

    International Nuclear Information System (INIS)

    Togami, Izumi; Sasai, Nobuya; Tsunoda, Masatoshi; Sei, Tetsurou; Sato, Shuhei; Yabuki, Takayuki; Hiraki, Yoshio

    2002-01-01

    The FAIR-HASTE method is a kind of noninvasive perfusion MR imaging obtained without the use of contrast media. By subtracting a flow-insensitive image from a flow-sensitive image, contrast enhancement of inflowing blood achieved. In the present study, we applied pulmonary perfusion FAIR-HASTE sequence for 23 patients with various pulmonary diseases, and compared the findings with those by pulmonary perfusion scintigraphy and Gadolinium perfusion MRI. Pulmonary perfusion imaging with the FAIR-HASTE method was possible in all clinical cases, and the findings corresponded well to those obtained by perfusion MRI using contrast media or pulmonary scintigraphy. The FAIR-HASTE method is a promising method for the evaluation of pulmonary perfusion. (author)

  7. Advanced magnetic resonance imaging methods for planning and monitoring radiation therapy in patients with high-grade glioma.

    Science.gov (United States)

    Lupo, Janine M; Nelson, Sarah J

    2014-10-01

    This review explores how the integration of advanced imaging methods with high-quality anatomical images significantly improves the characterization, target definition, assessment of response to therapy, and overall management of patients with high-grade glioma. Metrics derived from diffusion-, perfusion-, and susceptibility-weighted magnetic resonance imaging in conjunction with magnetic resonance spectroscopic imaging, allows us to characterize regions of edema, hypoxia, increased cellularity, and necrosis within heterogeneous tumor and surrounding brain tissue. Quantification of such measures may provide a more reliable initial representation of tumor delineation and response to therapy than changes in the contrast-enhancing or T2 lesion alone and have a significant effect on targeting resection, planning radiation, and assessing treatment effectiveness. In the long term, implementation of these imaging methodologies can also aid in the identification of recurrent tumor and its differentiation from treatment-related confounds and facilitate the detection of radiationinduced vascular injury in otherwise normal-appearing brain tissue.

  8. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium Sample Handling 8 to 10 Plutonium by Controlled-Potential Coulometry Plutonium by Ceric Sulfate Titration Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 11 to 18 Carbon (Total) by Direct Combustion–Thermal Conductivity 19 to 30 Total Chlorine and Fluorine by Pyrohydrolysis 31 to 38 Sulfur by Distillation Spectrophotometry 39 to 47 Plutonium Isotopic Analysis by Mass Spectrometry Rare Earth Elements by Spectroscopy 48 to 55 Trace Elements by Carrier–Distillation Spectroscopy 56 to 63 Impurities by ICP-AES Impurity Elements by Spark-Source Mass Spectrography 64 to 70 Moisture by the Coulomet...

  9. Three-Dimensional Elasticity Solutions for Sound Radiation of Functionally Graded Materials Plates considering State Space Method

    Directory of Open Access Journals (Sweden)

    Tieliang Yang

    2016-01-01

    Full Text Available This paper presents an analytical study for sound radiation of functionally graded materials (FGM plate based on the three-dimensional theory of elasticity. The FGM plate is a mixture of metal and ceramic, and its material properties are assumed to have smooth and continuous variation in the thickness direction according to a power-law distribution in terms of volume fractions of the constituents. Based on the three-dimensional theory of elasticity and state space method, the governing equations with variable coefficients of the FGM plate are derived. The sound radiation of the vibration plate is calculated with Rayleigh integral. Comparisons of the present results with those of solutions in the available literature are made and good agreements are achieved. Finally, some parametric studies are carried out to investigate the sound radiation properties of FGM plates.

  10. The kinetic of mass loss of grades A and B of melted TNT by isothermal and non-isothermal gravimetric methods

    Directory of Open Access Journals (Sweden)

    Hamid Reza Pouretedal

    2018-04-01

    Full Text Available The kinetic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 °C, respectively, were studied by isothermal and non-isothermal gravimetric methods. In isothermal method, the mass loss of samples in containers of glass and aluminum was followed in temperatures of 80, 90 and 100 °C. The kinetic of the mass loss of the samples in the aluminum container was higher than the kinetic of it in the glass container that can be related to the effects of heat transfer and catalytic of aluminum metal. Also, the presence of impurities in grade B was due to increasing of kinetic of mass loss of it versus grade A. The non-isothermal curves were obtained in range of 30–330 °C at heating rates of 10, 15 and 20 °C⋅min−1. The TG/DTG data were used for determination of activation energy (Ea of mass loss of TNT samples upon degradation by using Ozawa, Kissinger, Ozawa-Flynn-Wall (OFW and Kissinger-Akahira-Sunose (KAS methods as model free methods. The activation energies of grades of A and B of TNT was obtained 99–120 and 66–70 kJ mol−1, respectively. The lower values of activation energy of the degradation reaction of grade B confirm the effect of impurities in the kinetics of mass loss of this grade. Keywords: TNT, Isothermal, Non-isothermal, Kinetic, Mass loss

  11. Susceptibility Imaging in Glial Tumor Grading; Using 3 Tesla Magnetic Resonance (MR) System and 32 Channel Head Coil.

    Science.gov (United States)

    Aydin, Omer; Buyukkaya, Ramazan; Hakyemez, Bahattin

    2017-01-01

    Susceptibility weighted imaging (SWI) is a velocity compensated, high-resolution three-dimensional (3D) spoiled gradient-echo sequence that uses magnitude and filtered-phase data. SWI seems to be a valuable tool for non-invasive evaluation of central nervous system gliomas. Relative cerebral blood volume (rCBV) ratio is one of the best noninvasive methods for glioma grading. Degree of intratumoral susceptibility signal (ITSS) on SWI correlates with rCBV ratio and histopathological grade. This study investigated the effectiveness of ITSS grading and rCBV ratio in preoperative assessment. Thirty-one patients (17 males and 14 females) with histopathogical diagnosis of glial tumor undergoing routine cranial MRI, SWI, and perfusion MRI examinations between October 2011 and July 2013 were retrospectively enrolled. All examinations were performed using 3T apparatus with 32-channel head coil. We used ITSS number for SWI grading. Correlations between SWI grade, rCBV ratio, and pathological grading were evaluated. ROC analysis was performed to determine the optimal rCBV ratio to distinguish between high-grade and low-grade glial tumors. There was a strong positive correlation between both pathological and SWI grading. We determined the optimal rCBV ratio to discriminate between high-grade and low-grade tumors to be 2.21. In conclusion, perfusion MRI and SWI using 3T MR and 32-channel head coil may provide useful information for preoperative glial tumor grading. SWI can be used as an accessory to perfusion MR technique in preoperative tumor grading.

  12. Quality Control Assays for Clinical-Grade Human Mesenchymal Stromal Cells: Methods for ATMP Release.

    Science.gov (United States)

    Radrizzani, Marina; Soncin, Sabrina; Lo Cicero, Viviana; Andriolo, Gabriella; Bolis, Sara; Turchetto, Lucia

    2016-01-01

    Mesenchymal stromal/stem cells (MSC) are promising candidates for the development of cell-based therapies for various diseases and are currently being evaluated in a number of clinical trials (Sharma et al., Transfusion 54:1418-1437, 2014; Ikebe and Suzuki, Biomed Res Int 2014:951512, 2014). MSC for therapeutic applications are classified as advanced therapy medicinal products (ATMP) (Regulation (EC) No 1394/2007 of the European Parliament and of the Council of 13 November 2007 on advanced therapy medicinal products and amending Directive 2001/83/EC and Regulation (EC) No 726/2004) and must be prepared according to good manufacturing practices ( http://ec.europa.eu/health/documents/eudralex/vol-4 ). They may be derived from different starting materials (mainly bone marrow (BM), adipose tissue, or cord blood) and applied as fresh or cryopreserved products, in the autologous as well as an allogeneic context (Sharma et al., Transfusion 54:1418-1437, 2014; Ikebe and Suzuki, Biomed Res Int 2014:951512, 2014; Sensebé and Bourin, Transplantation 87(9 Suppl):S49-S53, 2009). In any case, they require an approved and well-defined panel of assays in order to be released for clinical use.This chapter describes analytical methods implemented and performed in our cell factory as part of the release strategy for an ATMP consisting of frozen autologous BM-derived MSC. Such methods are designed to assess the safety (sterility, endotoxin, and mycoplasma assays) and identity/potency (cell count and viability, immunophenotype and clonogenic assay) of the final product. Some assays are also applied to the biological starting material (sterility) or carried out as in-process controls (sterility, cell count and viability, immunophenotype, clonogenic assay).The validation strategy for each analytical method is described in the accompanying Chapter 20 .

  13. Rapid methods for the extraction and archiving of molecular grade fungal genomic DNA.

    Science.gov (United States)

    Borman, Andrew M; Palmer, Michael; Johnson, Elizabeth M

    2013-01-01

    The rapid and inexpensive extraction of fungal genomic DNA that is of sufficient quality for molecular approaches is central to the molecular identification, epidemiological analysis, taxonomy, and strain typing of pathogenic fungi. Although many commercially available and in-house extraction procedures do eliminate the majority of contaminants that commonly inhibit molecular approaches, the inherent difficulties in breaking fungal cell walls lead to protocols that are labor intensive and that routinely take several hours to complete. Here we describe several methods that we have developed in our laboratory that allow the extremely rapid and inexpensive preparation of fungal genomic DNA.

  14. A Modified Kirchhoff plate theory for Free Vibration analysis of functionally graded material plates using meshfree method

    Science.gov (United States)

    Nguyen Van Do, Vuong

    2018-04-01

    In this paper, a modified Kirchhoff theory is presented for free vibration analyses of functionally graded material (FGM) plate based on modified radial point interpolation method (RPIM). The shear deformation effects are taken account into modified theory to ignore the locking phenomenon of thin plates. Due to the proposed refined plate theory, the number of independent unknowns reduces one variable and exists with four degrees of freedom per node. The simulated free vibration results employed by the modified RPIM are compared with the other analytical solutions to verify the effectiveness and the accuracy of the developed mesh-free method. Detail parametric studies of the proposed method are then conducted including the effectiveness of thickness ratio, boundary condition and material inhomogeneity on the sample problems of square plates. Results illustrated that the modified mesh-free RPIM can effectively predict the numerical calculation as compared to the exact solutions. The obtained numerical results are indicated that the proposed method are stable and well accurate prediction to evaluate with other published analyses.

  15. Standard test methods for chemical and spectrochemical analysis of nuclear-Grade silver-indium-cadmium alloys

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1990-01-01

    1.1 These test methods cover procedures for the chemical and spectrochemical analysis of nuclear grade silver-indium-cadmium (Ag-In-Cd) alloys to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Silver, Indium, and Cadmium by a Titration Method 7-15 Trace Impurities by Carrier-Distillation Spectro- chemical Method 16-22 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard and precautionary statements, see Section 5 and Practices E50. 7.1 This test method is applicable to the determination of silver, indium, and cadmium in alloys of approximately 80 % silver, 15 % indium, and 5 % cadmium used in nuclear reactor control r...

  16. Effect of patient age on accuracy of primary MRI signs of long head of biceps tearing and instability in the shoulder. An MRI-arthroscopy correlation study

    Energy Technology Data Exchange (ETDEWEB)

    Borrero, Camilo G.; Costello, Joanna; Vyas, Dharmesh [University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Bertolet, Marnie [University of Pittsburgh School of Medicine, Pittsburgh, PA (United States)

    2018-02-15

    To determine the effect of patient age on the accuracy of primary MRI signs of long head of biceps (LHB) tendon tearing and instability in the shoulder using arthroscopy as a reference standard. Subjects with MRI studies and subsequent arthroscopy documenting LHB tendon pathology were identified and organized into three age groups (18-40, 41-60, 61-87). Normal and tendinopathic tendons were labeled grade 0, partial tears grade 1 and full tears grade 2. Two radiologists blinded to arthroscopic data graded MRI studies independently. Prevalence of disease, MRI accuracy for outcomes of interest, and inter-reader agreement were calculated. Eighty-nine subjects fulfilled inclusion criteria with 36 grade 0, 36 grade 1 and 17 grade 2 tendons found at arthroscopy. MRI sensitivity, regardless of age, ranged between 67-86% for grade 0, 72-94% for grade 1 and 82-94% for grade 2 tendons. Specificity ranged between 83-96% for grade 0, 75-85% for grade 1 and 99-100% for grade 2 tendons. MRI accuracy for detection of each LHB category was calculated for each age group. MRI was found to be least sensitive for grade 0 and 1 LHB tendons in the middle-aged group with sensitivity between 55-85% for grade 0 and 53-88% for grade 1 tendons. Agreement between MRI readers was moderate with an unweighted kappa statistic of 62%. MRI accuracy was moderate to excellent and agreement between MRI readers was moderate. MRI appears to be less accurate in characterizing lower grades of LHB tendon disease in middle-aged subjects. (orig.)

  17. SU-C-17A-03: Evaluation of Deformable Image Registration Methods Between MRI and CT for Prostate Cancer Radiotherapy

    International Nuclear Information System (INIS)

    Wen, N; Glide-Hurst, C; Zhong, H; Chin, K; Kumarasiri, A; Liu, C; Liu, M; Siddiqui, S

    2014-01-01

    Purpose: We evaluated the performance of two commercially available and one open source B-Spline deformable image registration (DIR) algorithms between T2-weighted MRI and treatment planning CT using the DICE indices. Methods: CT simulation (CT-SIM) and MR simulation (MR-SIM) for four prostate cancer patients were conducted on the same day using the same setup and immobilization devices. CT images (120 kVp, 500 mAs, voxel size = 1.1x1.1x3.0 mm3) were acquired using an open-bore CT scanner. T2-weighted Turbo Spine Echo (T2W-TSE) images (TE/TR/α = 80/4560 ms/90°, voxel size = 0.7×0.7×2.5 mm3) were scanned on a 1.0T high field open MR-SIM. Prostates, seminal vesicles, rectum and bladders were delineated on both T2W-TSE and CT images by the attending physician. T2W-TSE images were registered to CT images using three DIR algorithms, SmartAdapt (Varian), Velocity AI (Velocity) and Elastix (Klein et al 2010) and contours were propagated. DIR results were evaluated quantitatively or qualitatively by image comparison and calculating organ DICE indices. Results: Significant differences in the contours of prostate and seminal vesicles were observed between MR and CT. On average, volume changes of the propagated contours were 5%, 2%, 160% and 8% for the prostate, seminal vesicles, bladder and rectum respectively. Corresponding mean DICE indices were 0.7, 0.5, 0.8, and 0.7. The intraclass correlation coefficient (ICC) was 0.9 among three algorithms for the Dice indices. Conclusion: Three DIR algorithms for CT/MR registration yielded similar results for organ propagation. Due to the different soft tissue contrasts between MRI and CT, organ delineation of prostate and SVs varied significantly, thus efforts to develop other DIR evaluation metrics are warranted. Conflict of interest: Submitting institution has research agreements with Varian Medical System and Philips Healthcare

  18. SU-C-17A-03: Evaluation of Deformable Image Registration Methods Between MRI and CT for Prostate Cancer Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wen, N; Glide-Hurst, C; Zhong, H; Chin, K; Kumarasiri, A; Liu, C; Liu, M; Siddiqui, S [I Chetty, Henry Ford Health System, Detroit, MI (United States)

    2014-06-15

    Purpose: We evaluated the performance of two commercially available and one open source B-Spline deformable image registration (DIR) algorithms between T2-weighted MRI and treatment planning CT using the DICE indices. Methods: CT simulation (CT-SIM) and MR simulation (MR-SIM) for four prostate cancer patients were conducted on the same day using the same setup and immobilization devices. CT images (120 kVp, 500 mAs, voxel size = 1.1x1.1x3.0 mm3) were acquired using an open-bore CT scanner. T2-weighted Turbo Spine Echo (T2W-TSE) images (TE/TR/α = 80/4560 ms/90°, voxel size = 0.7×0.7×2.5 mm3) were scanned on a 1.0T high field open MR-SIM. Prostates, seminal vesicles, rectum and bladders were delineated on both T2W-TSE and CT images by the attending physician. T2W-TSE images were registered to CT images using three DIR algorithms, SmartAdapt (Varian), Velocity AI (Velocity) and Elastix (Klein et al 2010) and contours were propagated. DIR results were evaluated quantitatively or qualitatively by image comparison and calculating organ DICE indices. Results: Significant differences in the contours of prostate and seminal vesicles were observed between MR and CT. On average, volume changes of the propagated contours were 5%, 2%, 160% and 8% for the prostate, seminal vesicles, bladder and rectum respectively. Corresponding mean DICE indices were 0.7, 0.5, 0.8, and 0.7. The intraclass correlation coefficient (ICC) was 0.9 among three algorithms for the Dice indices. Conclusion: Three DIR algorithms for CT/MR registration yielded similar results for organ propagation. Due to the different soft tissue contrasts between MRI and CT, organ delineation of prostate and SVs varied significantly, thus efforts to develop other DIR evaluation metrics are warranted. Conflict of interest: Submitting institution has research agreements with Varian Medical System and Philips Healthcare.

  19. Optimizing signal intensity correction during evaluation of hepatic parenchymal enhancement on gadoxetate disodium-enhanced MRI: Comparison of three methods

    International Nuclear Information System (INIS)

    Onoda, Minori; Hyodo, Tomoko; Murakami, Takamichi; Okada, Masahiro; Uto, Tatsuro; Hori, Masatoshi; Miyati, Tosiaki

    2015-01-01

    Highlights: •Signal intensity is often used to evaluate hepatic enhancement with Gd-EOB-DTPA in the hepatobiliary phase. •Comparison of uncorrected signal intensity with T 1 value revealed signal intensity instability. •Measurement of uncorrected liver SI or SNR often yields erroneous results on late-phase gadoxetate MRI due to shimming and other optimization techniques. •Signal intensity corrected by scale and rescale slope from DICOM data gave comparable results. -- Abstract: Objective: To compare signal intensity (SI) correction using scale and rescale slopes with SI correction using SIs of spleen and muscle for quantifying multiphase hepatic contrast enhancement with Gd-EOB-DTPA by assessing their correlation with T 1 values generated from Look-Locker turbo-field-echo (LL-TFE) sequence data (ER-T 1 ). Materials and methods: Thirty patients underwent Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in this prospective clinical study. For each patient, breath-hold T 1 -weighted fat-suppressed three-dimensional (3D) gradient echo sequences (e-THRIVE) were acquired before and 2 (first phase), 10 (second phase), and 20 min (third phase) after intravenous Gd-EOB-DTPA. Look-Locker turbo-field-echo (LL-TFE) sequences were acquired before and 1.5 (first phase), 8 (second phase), and 18 min (third phase) postcontrast. The liver parenchyma enhancement ratios (ER) of each phase were calculated using the SI from e-THRIVE sequences (ER-SI) and the T 1 values generated from LL-TFE sequence data (ER-T 1 ) respectively. ER-SIs were calculated in three ways: (1) comparing with splenic SI (ER-SI-s), (2) comparing with muscle SI (ER-SI-m), (3) using scale and rescale slopes obtained from DICOM headers (ER-SI-c), to eliminate the effects of receiver gain and scaling. For each of the first, second and third phases, correlation and agreement were assessed between each ER-SI and ER-T 1 . Results: In the first phase, all ER-SIs correlated weakly with ER-T 1 . In the second

  20. Method of Modeling Questions for Automated Grading of Students’ Responses in E-Learning Systems

    Directory of Open Access Journals (Sweden)

    A. A. Gurchenkov

    2015-01-01

    Full Text Available Introduction. Problem relevance. The capability to check a solution of practical problems automatically is an important functionality of any learning management system (LMS. Complex types of questions, implying creative approach to problem solving are of particular interest. There are a lot of studies presenting automated scoring algorithms of students' answers, such as mathematical expressions, graphs, molecules, etc. However, the most common types of problems in the open LMS that are being actively implemented in Russian and foreign universities (Moodle, Sakai, Ilias etc. remain simple types of questions such as, for example, multiple choice.Study subject and goal. The purpose of study is to create a method that allows integrating arbitrary algorithms of answer scoring into any existing LMS, as well as its practical implementation in the form of an independent software module, which will handle questions in LMS.Method. The model for objects of type "algorithmic question" is considered. A unified format for storing objects of this type, allowing keeping their state, is developed. The algorithm is a set of variables, which defines the responses versus input data (or vice versa. Basis variables (input are selected pseudo-randomly from a predetermined range, and based on these values resulting variables (responses are calculated. This approach allows us to synthesize variations of the same question. State of the question is saved by means of "seed" of pseudo-random number generator. A set of algorithmic problems was used to build the lifecycle management functions, namely: initialization create (, rendering render (, and evaluation answer (. These functions lay the foundation for the Application Program Interface (API and allow us to control software module responsible for the questions in LMS.Practical results. This study is completed with the implementation of software module responsible for mapping the interaction with the student and automated

  1. Similar judgment method of brain neural pathway using DT-MRI

    International Nuclear Information System (INIS)

    Watashiba, Yasuhiro; Sakamoto, Naohisa; Sakai, Koji; Koyamada, Koji; Kanazawa, Masanori; Doi, Akio

    2008-01-01

    Nowadays, the visualization of brain neural pathway extracted by the tractography technology is thought as a useful effective tool for the detection of involved area and the analysis of sick cause by comparison of difference of normal and patient's nerve fiber configurations and for the support of the surgery planning and the forecast of progress after an operation. So far, for the observation of the brain neural pathway, the method of the user's subjectively judging the 3D shape of them displayed in the image has been used. However, in this kind of subjective observation, verification of the propriety for the diagnostic result is difficult, in addition it cannot obtain sufficient reliability. Therefore, we think that the system to compare the shape based on a quantitative evaluation is necessary. To resolve this problem, we propose the system that enables the shape of the brain neural pathway extracted by the tractography technology to be compared quantitatively. The proposed system realized to calculate similarity between two neural pathways, and to display the difference area according to the similarity. (author)

  2. A novel background field removal method for MRI using projection onto dipole fields (PDF).

    Science.gov (United States)

    Liu, Tian; Khalidov, Ildar; de Rochefort, Ludovic; Spincemaille, Pascal; Liu, Jing; Tsiouris, A John; Wang, Yi

    2011-11-01

    For optimal image quality in susceptibility-weighted imaging and accurate quantification of susceptibility, it is necessary to isolate the local field generated by local magnetic sources (such as iron) from the background field that arises from imperfect shimming and variations in magnetic susceptibility of surrounding tissues (including air). Previous background removal techniques have limited effectiveness depending on the accuracy of model assumptions or information input. In this article, we report an observation that the magnetic field for a dipole outside a given region of interest (ROI) is approximately orthogonal to the magnetic field of a dipole inside the ROI. Accordingly, we propose a nonparametric background field removal technique based on projection onto dipole fields (PDF). In this PDF technique, the background field inside an ROI is decomposed into a field originating from dipoles outside the ROI using the projection theorem in Hilbert space. This novel PDF background removal technique was validated on a numerical simulation and a phantom experiment and was applied in human brain imaging, demonstrating substantial improvement in background field removal compared with the commonly used high-pass filtering method. Copyright © 2011 John Wiley & Sons, Ltd.

  3. Experimental investigation and optimization of welding process parameters for various steel grades using NN tool and Taguchi method

    Science.gov (United States)

    Soni, Sourabh Kumar; Thomas, Benedict

    2018-04-01

    The term "weldability" has been used to describe a wide variety of characteristics when a material is subjected to welding. In our analysis we perform experimental investigation to estimate the tensile strength of welded joint strength and then optimization of welding process parameters by using taguchi method and Artificial Neural Network (ANN) tool in MINITAB and MATLAB software respectively. The study reveals the influence on weldability of steel by varying composition of steel by mechanical characterization. At first we prepare the samples of different grades of steel (EN8, EN 19, EN 24). The samples were welded together by metal inert gas welding process and then tensile testing on Universal testing machine (UTM) was conducted for the same to evaluate the tensile strength of the welded steel specimens. Further comparative study was performed to find the effects of welding parameter on quality of weld strength by employing Taguchi method and Neural Network tool. Finally we concluded that taguchi method and Neural Network Tool is much efficient technique for optimization.

  4. A probability-based multi-cycle sorting method for 4D-MRI: A simulation study.

    Science.gov (United States)

    Liang, Xiao; Yin, Fang-Fang; Liu, Yilin; Cai, Jing

    2016-12-01

    To develop a novel probability-based sorting method capable of generating multiple breathing cycles of 4D-MRI images and to evaluate performance of this new method by comparing with conventional phase-based methods in terms of image quality and tumor motion measurement. Based on previous findings that breathing motion probability density function (PDF) of a single breathing cycle is dramatically different from true stabilized PDF that resulted from many breathing cycles, it is expected that a probability-based sorting method capable of generating multiple breathing cycles of 4D images may capture breathing variation information missing from conventional single-cycle sorting methods. The overall idea is to identify a few main breathing cycles (and their corresponding weightings) that can best represent the main breathing patterns of the patient and then reconstruct a set of 4D images for each of the identified main breathing cycles. This method is implemented in three steps: (1) The breathing signal is decomposed into individual breathing cycles, characterized by amplitude, and period; (2) individual breathing cycles are grouped based on amplitude and period to determine the main breathing cycles. If a group contains more than 10% of all breathing cycles in a breathing signal, it is determined as a main breathing pattern group and is represented by the average of individual breathing cycles in the group; (3) for each main breathing cycle, a set of 4D images is reconstructed using a result-driven sorting method adapted from our previous study. The probability-based sorting method was first tested on 26 patients' breathing signals to evaluate its feasibility of improving target motion PDF. The new method was subsequently tested for a sequential image acquisition scheme on the 4D digital extended cardiac torso (XCAT) phantom. Performance of the probability-based and conventional sorting methods was evaluated in terms of target volume precision and accuracy as measured

  5. SU-D-207B-04: Morphological Features of MRI as a Correlate of Capsular Contracture in Breast Cancer Patients with Implant-Based Reconstructions

    International Nuclear Information System (INIS)

    Tyagi, N; Sutton, E; Hunt, M; Apte, A; Zhang, J; Oh, J; Mechalakos, J; Mehrara, B; Matros, E; Ho, A

    2016-01-01

    Purpose: Capsular contracture (CC) is a serious complication in patients receiving implant-based reconstruction for breast cancer. The goal of this study was to identify image-based correlates of CC using MRI imaging in breast cancer patients who received both MRI and clinical evaluation following reconstructive surgery. Methods: We analyzed a retrospective dataset of 50 patients who had both a diagnostic MR and a plastic surgeon’s evaluations of CC score (Baker’s score) within a six month period following mastectomy and reconstructive surgery. T2w sagittal MRIs (TR/TE = 3500/102 ms, slice thickness = 4 mm) were used for morphological shape features (roundness, eccentricity, solidity, extent and ratio-length) and histogram features (median, skewness and kurtosis) of the implant and the pectoralis muscle overlying the implant. Implant and pectoralis muscles were segmented in 3D using Computation Environment for Radiological Research (CERR) and shape and histogram features were calculated as a function of Baker’s score. Results: Shape features such as roundness and eccentricity were statistically significant in differentiating grade 1 and grade 2 (p = 0.009; p = 0.06) as well as grade 1 and grade 3 CC (p = 0.001; p = 0.006). Solidity and extent were statistically significant in differentiating grade 1 and grade 3 CC (p = 0.04; p = 0.04). Ratio-length was statistically significant in differentiating all grades of CC except grade 2 and grade 3 that showed borderline significance (p = 0.06). The muscle thickness, median intensity and kurtosis were significant in differentiating between grade 1 and grade 3 (p = 0.02), grade 1 and grade 2 (p = 0.03) and grade 1 and grade 3 (p = 0.01) respectively. Conclusion: Morphological shape features described on MR images were associated with the severity of CC. MRI may be important in objectively evaluating outcomes in breast cancer patients who undergo implant reconstruction.

  6. MRI-determined liver proton density fat fraction, with MRS validation: Comparison of regions of interest sampling methods in patients with type 2 diabetes.

    Science.gov (United States)

    Vu, Kim-Nhien; Gilbert, Guillaume; Chalut, Marianne; Chagnon, Miguel; Chartrand, Gabriel; Tang, An

    2016-05-01

    To assess the agreement between published magnetic resonance imaging (MRI)-based regions of interest (ROI) sampling methods using liver mean proton density fat fraction (PDFF) as the reference standard. This retrospective, internal review board-approved study was conducted in 35 patients with type 2 diabetes. Liver PDFF was measured by magnetic resonance spectroscopy (MRS) using a stimulated-echo acquisition mode sequence and MRI using a multiecho spoiled gradient-recalled echo sequence at 3.0T. ROI sampling methods reported in the literature were reproduced and liver mean PDFF obtained by whole-liver segmentation was used as the reference standard. Intraclass correlation coefficients (ICCs), Bland-Altman analysis, repeated-measures analysis of variance (ANOVA), and paired t-tests were performed. ICC between MRS and MRI-PDFF was 0.916. Bland-Altman analysis showed excellent intermethod agreement with a bias of -1.5 ± 2.8%. The repeated-measures ANOVA found no systematic variation of PDFF among the nine liver segments. The correlation between liver mean PDFF and ROI sampling methods was very good to excellent (0.873 to 0.975). Paired t-tests revealed significant differences (P sampling methods that exclusively or predominantly sampled the right lobe. Significant correlations with mean PDFF were found with sampling methods that included higher number of segments, total area equal or larger than 5 cm(2) , or sampled both lobes (P = 0.001, 0.023, and 0.002, respectively). MRI-PDFF quantification methods should sample each liver segment in both lobes and include a total surface area equal or larger than 5 cm(2) to provide a close estimate of the liver mean PDFF. © 2015 Wiley Periodicals, Inc.

  7. Whole-body MRI in preoperative diagnostics of breast cancer. A comparison with staging methods according to the S 3 guidelines

    International Nuclear Information System (INIS)

    Hausmann, D.; Schoenberg, S.O.; Neff, K.W.; Dinter, D.J.; Kern, C.; Schroeder, M.T.; Suetterlin, M.

    2011-01-01

    Purpose: The German Society of Senology (step-3 guidelines for the early recognition of breast cancer in Germany) recommends whole-body staging including chest X-ray, ultrasound of the liver and bone scintigraphy before systemic therapy in patients with breast cancer. The performance of these three examinations is time-consuming and involves radiation exposure. Whole-body MR imaging (WB-MRI) allows staging in a single examination without radiation exposure. The purpose of this study was to compare the diagnostic accuracy of WB-MRI with staging according to the guidelines. Materials and Methods: During 04/07 and 06/09, the initial staging in 51 patients (56 ± 12 yrs) with breast cancer (24 patients with lymph node metastases) was performed according to the S 3-guidelines. Additionally, all patients underwent contrast-enhanced WB-MRI (1.5-Tesla-Magnetom Avanto, Siemens, Erlangen). The findings of the different modalities were compared after correlation of the lesions by follow-up. The detection of suspicious findings and the accuracy of prediction of malignancy of the detected lesions were evaluated. Results: Overall, 14 metastases were detected in 4 of 51 patients after completion of the follow-up. By means of WB-MRI, all 14 metastases could be detected, while just 4 of these metastases were identified by the conventional methods. Conclusion: The detection of distant metastases has an important impact on patient management. In this study WB-MRI in breast cancer staging has shown promising results in regard to possible clinical implementation as a matter of routine staging. (orig.)

  8. PI-RADS classification. Structured reporting for MRI of the prostate

    International Nuclear Information System (INIS)

    Roethke, Matthias; Schlemmer, H.P.; Blondin, D.; Franiel, T.

    2013-01-01

    Purpose: To flesh out the ESUR guidelines for the standardized interpretation of multiparametric magnetic resonance imaging (mMRI) for the detection of prostate cancer and to present a graphic reporting scheme for improved communication of findings to urologists. Materials and Methods: The ESUR has recently published a structured reporting system for mMRI of the prostate (PI-RADS). This system involves the use of 5-point Likert scales for grading the findings obtained with different MRI techniques. The mMRI includes T2-weighted MRI, diffusion-weighted imaging, dynamic contrast-enhanced MRI, and MR spectroscopy. In a first step, the fundamentals of technical implementation were determined by consensus, taking into account in particular the German-speaking community. Then, representative images were selected by consensus on the basis of examinations of the three institutions. In addition, scoring intervals for an aggregated PI-RADS score were determined in consensus. Results: The multiparametric methods were discussed critically with regard to implementation and the current status. Criteria used for grading mMRI findings with the PI-RADS classification were concretized by succinct examples. Using the consensus table for aggregated scoring in a clinical setting, a diagnosis of suspected prostate cancer should be made if the PI-RADS score is 4 or higher (≥ 10 points if 3 techniques are used or ≥ 13 points if 4 techniques are used). Finally, a graphic scheme was developed for communicating mMRI prostate findings. Conclusion: Structured reporting according to the ESUR guidelines contributes to quality assurance by standardizing prostate mMRI, and it facilities the communication of findings to urologists. (orig.)

  9. In the assessment of supratentorial glioma grade: The combined role of multivoxel proton MR spectroscopy and diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Q.-G. [Department of Neuroradiology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Xu, H.-B., E-mail: xuhaibo1120@hotmail.com [Department of Neuroradiology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Liu, F.; Guo, W. [Department of Neuroradiology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Kong, X.-C. [Department of Imaging technology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Wu, Y. [Department of Maternal and Child Health Care, Public Health School, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China)

    2011-10-15

    Aim: To detect a difference in the parameters derived from proton magnetic resonance spectroscopy ({sup 1}H-MRS) and diffusion tensor imaging (DTI) between low-grade and high-grade gliomas, and to evaluate whether the combination of these two techniques can improve the diagnostic accuracy of conventional magnetic resonance imaging (MRI) in supratentorial glioma grading. Materials and methods: Thirty patients with histologically proved supratentorial brain gliomas (12 low grade, 18 high grade) were prospectively evaluated with contrast material-enhanced MRI, DTI, and multivoxel {sup 1}H-MRS (135 ms echo time). The tumour grades determined using the three methods were then compared with those obtained at histopathology. Receiver operating characteristic (ROC) analyses were performed to determine the optimum thresholds for glioma grading. Independent sample t-test, Spearman's rank correlation, and the Fisher's exact test were also carried out for statistical analysis. p < 0.05 was considered statistically significant. Results: Statistically significant differences were found between the low-grade and high-grade gliomas for the choline (Cho)/creatine (Cr), N-acetylaspartate (NAA)/Cr, NAA/Cho ratio in the tumours (p < 0.01), apparent diffusion coefficient (ADC) value (p < 0.01), and fractional anisotropy (FA) value (p < 0.05) in the tumours. The NAA/Cr and NAA/Cho ratios and the calculated ADC value significantly correlated with the histological grading of the gliomas (p < 0.01). Using a threshold value of 0.66 for tumour NAA/Cr, 0.265 for NAA/Cho, 1118.1 x 10{sup -6} mm{sup 2}/s for the calculated ADC value, corresponding to the maximum Youden index from the ROC curve of the above-selected parameters, the resultant sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Kappa values were all higher and the fraction of misclassified tumour was lower when compared with conventional MRI. However, only NAA/Cho and

  10. The value of intraoperative sonography in low grade glioma surgery.

    Science.gov (United States)

    Petridis, Athanasios K; Anokhin, Maxim; Vavruska, Jan; Mahvash, Mehran; Scholz, Martin

    2015-04-01

    There is a number of different methods to localize a glioma intraoperatively. Neuronavigation, intraoperative MRI, 5-aminolevulinic acid, as well as intraoperative sonography. Every method has its advantages and disadvantages. Low grade gliomas do not show a specific signal with 5-aminolevulinic acid and are difficult to distinguish macroscopically from normal tissue. In the present study we stress out the importance of intraoperative diagnostic ultrasound for localization of low grade gliomas. We retrospectively evaluated the charts and MRIs of 34 patients with low grade gliomas operated in our department from 2011 until December 2014. The efficacy of ultrasound as an intraoperative navigational tool was assessed. In 15 patients ultrasound was used and in 19 not. Only histologically proven low grades gliomas (astrocytomas grade II) were evaluated. In none of the patients where ultrasound (combined with neuronavigation) was used (N=15) to find the tumors, the target was missed, whereas the exclusive use of neuronavigation missed the target in 5 of 19 cases of small subcortical low grade gliomas. Intraoperative ultrasound is an excellent tool in localizing low grade gliomas intraoperatively. It is an inexpensive, real time neuronavigational tool, which overcomes brain shift. Even when identifying the tumors with ultrasound is very reliable, the extend of resection and the decision to remove any residual tumor with the help of ultrasound is at the moment unreliable. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Development of Knowledge, Awareness, Global Warming Decreasing Behavior and Critical Thinking of Grade 11 Students Using the Four Noble Truths Method with Meta-Cognitive Techniques

    Science.gov (United States)

    Chattuchai, Sakkarin; Singseewo, Adisak; Suksringarm, Paitool

    2015-01-01

    This study aims to investigate the effects of learning environmental education on the knowledge, awareness, global warming decreasing behavior, and critical thinking of eighty grade 11 students from two classes. The Four Noble Truths method with metacognitive techniques and traditional teaching method were used for the investigation. The sample…

  12. Combined 18F-Fluciclovine PET/MRI Shows Potential for Detection and Characterization of High-Risk Prostate Cancer.

    Science.gov (United States)

    Elschot, Mattijs; Selnæs, Kirsten M; Sandsmark, Elise; Krüger-Stokke, Brage; Størkersen, Øystein; Giskeødegård, Guro F; Tessem, May-Britt; Moestue, Siver A; Bertilsson, Helena; Bathen, Tone F

    2018-05-01

    The objective of this study was to investigate whether quantitative imaging features derived from combined 18 F-fluciclovine PET/multiparametric MRI show potential for detection and characterization of primary prostate cancer. Methods: Twenty-eight patients diagnosed with high-risk prostate cancer underwent simultaneous 18 F-fluciclovine PET/MRI before radical prostatectomy. Volumes of interest (VOIs) for prostate tumors, benign prostatic hyperplasia (BPH) nodules, prostatitis, and healthy tissue were delineated on T2-weighted images, using histology as a reference. Tumor VOIs were marked as high-grade (≥Gleason grade group 3) or not. MRI and PET features were extracted on the voxel and VOI levels. Partial least-squared discriminant analysis (PLS-DA) with double leave-one-patient-out cross-validation was performed to distinguish tumors from benign tissue (BPH, prostatitis, or healthy tissue) and high-grade tumors from other tissue (low-grade tumors or benign tissue). The performance levels of PET, MRI, and combined PET/MRI features were compared using the area under the receiver-operating-characteristic curve (AUC). Results: Voxel and VOI features were extracted from 40 tumor VOIs (26 high-grade), 36 BPH VOIs, 6 prostatitis VOIs, and 37 healthy-tissue VOIs. PET/MRI performed better than MRI and PET alone for distinguishing tumors from benign tissue (AUCs of 87%, 81%, and 83%, respectively, at the voxel level and 96%, 93%, and 93%, respectively, at the VOI level) and high-grade tumors from other tissue (AUCs of 85%, 79%, and 81%, respectively, at the voxel level and 93%, 93%, and 91%, respectively, at the VOI level). T2-weighted MRI, diffusion-weighted MRI, and PET features were the most important for classification. Conclusion: Combined 18 F-fluciclovine PET/multiparametric MRI shows potential for improving detection and characterization of high-risk prostate cancer, in comparison to MRI and PET alone. © 2018 by the Society of Nuclear Medicine and Molecular

  13. Studying neuroanatomy using MRI.

    Science.gov (United States)

    Lerch, Jason P; van der Kouwe, André J W; Raznahan, Armin; Paus, Tomáš; Johansen-Berg, Heidi; Miller, Karla L; Smith, Stephen M; Fischl, Bruce; Sotiropoulos, Stamatios N

    2017-02-23

    The study of neuroanatomy using imaging enables key insights into how our brains function, are shaped by genes and environment, and change with development, aging and disease. Developments in MRI acquisition, image processing and data modeling have been key to these advances. However, MRI provides an indirect measurement of the biological signals we aim to investigate. Thus, artifacts and key questions of correct interpretation can confound the readouts provided by anatomical MRI. In this review we provide an overview of the methods for measuring macro- and mesoscopic structure and for inferring microstructural properties; we also describe key artifacts and confounds that can lead to incorrect conclusions. Ultimately, we believe that, although methods need to improve and caution is required in interpretation, structural MRI continues to have great promise in furthering our understanding of how the brain works.

  14. Highly-Accelerated Real-Time Cardiac Cine MRI Using k-t SPARSE-SENSE

    Science.gov (United States)

    Feng, Li; Srichai, Monvadi B.; Lim, Ruth P.; Harrison, Alexis; King, Wilson; Adluru, Ganesh; Dibella, Edward VR.; Sodickson, Daniel K.; Otazo, Ricardo; Kim, Daniel

    2012-01-01

    For patients with impaired breath-hold capacity and/or arrhythmias, real-time cine MRI may be more clinically useful than breath-hold cine MRI. However, commercially available real-time cine MRI methods using parallel imaging typically yield relatively poor spatio-temporal resolution due to their low image acquisition speed. We sought to achieve relatively high spatial resolution (~2.5mm × 2.5mm) and temporal resolution (~40ms), to produce high-quality real-time cine MR images that could be applied clinically for wall motion assessment and measurement of left ventricular (LV) function. In this work, we present an 8-fold accelerated real-time cardiac cine MRI pulse sequence using a combination of compressed sensing and parallel imaging (k-t SPARSE-SENSE). Compared with reference, breath-hold cine MRI, our 8-fold accelerated real-time cine MRI produced significantly worse qualitative grades (1–5 scale), but its image quality and temporal fidelity scores were above 3.0 (adequate) and artifacts and noise scores were below 3.0 (moderate), suggesting that acceptable diagnostic image quality can be achieved. Additionally, both 8-fold accelerated real-time cine and breath-hold cine MRI yielded comparable LV function measurements, with coefficient of variation cine MRI with k-t SPARSE-SENSE is a promising modality for rapid imaging of myocardial function. PMID:22887290

  15. Highly accelerated real-time cardiac cine MRI using k-t SPARSE-SENSE.

    Science.gov (United States)

    Feng, Li; Srichai, Monvadi B; Lim, Ruth P; Harrison, Alexis; King, Wilson; Adluru, Ganesh; Dibella, Edward V R; Sodickson, Daniel K; Otazo, Ricardo; Kim, Daniel

    2013-07-01

    For patients with impaired breath-hold capacity and/or arrhythmias, real-time cine MRI may be more clinically useful than breath-hold cine MRI. However, commercially available real-time cine MRI methods using parallel imaging typically yield relatively poor spatio-temporal resolution due to their low image acquisition speed. We sought to achieve relatively high spatial resolution (∼2.5 × 2.5 mm(2)) and temporal resolution (∼40 ms), to produce high-quality real-time cine MR images that could be applied clinically for wall motion assessment and measurement of left ventricular function. In this work, we present an eightfold accelerated real-time cardiac cine MRI pulse sequence using a combination of compressed sensing and parallel imaging (k-t SPARSE-SENSE). Compared with reference, breath-hold cine MRI, our eightfold accelerated real-time cine MRI produced significantly worse qualitative grades (1-5 scale), but its image quality and temporal fidelity scores were above 3.0 (adequate) and artifacts and noise scores were below 3.0 (moderate), suggesting that acceptable diagnostic image quality can be achieved. Additionally, both eightfold accelerated real-time cine and breath-hold cine MRI yielded comparable left ventricular function measurements, with coefficient of variation cine MRI with k-t SPARSE-SENSE is a promising modality for rapid imaging of myocardial function. Copyright © 2012 Wiley Periodicals, Inc.

  16. Explosive welding method for manufacturing ITER-grade 316L(N)/CuCrZr hollow structural member

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Rui, E-mail: mr9980@163.com [PLA University of Science and Technology, Nanjing 210007 (China); Wang, Yaohua [PLA University of Science and Technology, Nanjing 210007 (China); Wu, Jihong [Southwestern Institute of Physics, Chengdu 610041 (China); Duan, Mianjun [PLA University of Science and Technology, Nanjing 210007 (China)

    2014-12-15

    Highlights: • Develop a new explosive welding method to fabricate the cooling channel of FW. • Utilize effective energy model to accurately calculate optimal welding parameters. • Provide an efficient way for manufacturing high-ductility hollow structural member. - Abstract: In this study, a new explosive welding method provided an effective way for manufacturing ITER-grade 316L(N)/CuCrZr hollow structural member. The welding parameters (stand-off distance and explosion rate) were calculated respectively using equivalent frontal collision wave model and effective energy model. The welded samples were subject to two step heat treatment cycles (solution annealing and aging). Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to analyze the microstructure of bonding interface. The mechanical properties of the welded samples were evaluated through microhardness test and tensile test. Moreover, the sealing property of the welded specimens was measured through helium leak test. Microstructural analysis showed that the welded sample using effective energy model had an ideal wavy interface. The results of microhardness test revealed an increase in hardness for both sides near to the bonding interface. And the hardening phenomenon of interface region disappeared after the solution annealing. SEM observation indicated that the samples with the post heat treatments exhibited a ductile fracture with dimple features after tensile test. After the specimens undergo aging strengthening, there was an obvious increase in the strength for all specimens. The helium leak test results have proven that the welded specimens are soundness.

  17. Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

  18. Practical state of health estimation of power batteries based on Delphi method and grey relational grade analysis

    Science.gov (United States)

    Sun, Bingxiang; Jiang, Jiuchun; Zheng, Fangdan; Zhao, Wei; Liaw, Bor Yann; Ruan, Haijun; Han, Zhiqiang; Zhang, Weige

    2015-05-01

    The state of health (SOH) estimation is very critical to battery management system to ensure the safety and reliability of EV battery operation. Here, we used a unique hybrid approach to enable complex SOH estimations. The approach hybridizes the Delphi method known for its simplicity and effectiveness in applying weighting factors for complicated decision-making and the grey relational grade analysis (GRGA) for multi-factor optimization. Six critical factors were used in the consideration for SOH estimation: peak power at 30% state-of-charge (SOC), capacity, the voltage drop at 30% SOC with a C/3 pulse, the temperature rises at the end of discharge and charge at 1C; respectively, and the open circuit voltage at the end of charge after 1-h rest. The weighting of these factors for SOH estimation was scored by the 'experts' in the Delphi method, indicating the influencing power of each factor on SOH. The parameters for these factors expressing the battery state variations are optimized by GRGA. Eight battery cells were used to illustrate the principle and methodology to estimate the SOH by this hybrid approach, and the results were compared with those based on capacity and power capability. The contrast among different SOH estimations is discussed.

  19. [Research on K-means clustering segmentation method for MRI brain image based on selecting multi-peaks in gray histogram].

    Science.gov (United States)

    Chen, Zhaoxue; Yu, Haizhong; Chen, Hao

    2013-12-01

    To solve the problem of traditional K-means clustering in which initial clustering centers are selected randomly, we proposed a new K-means segmentation algorithm based on robustly selecting 'peaks' standing for White Matter, Gray Matter and Cerebrospinal Fluid in multi-peaks gray histogram of MRI brain image. The new algorithm takes gray value of selected histogram 'peaks' as the initial K-means clustering center and can segment the MRI brain image into three parts of tissue more effectively, accurately, steadily and successfully. Massive experiments have proved that the proposed algorithm can overcome many shortcomings caused by traditional K-means clustering method such as low efficiency, veracity, robustness and time consuming. The histogram 'peak' selecting idea of the proposed segmentootion method is of more universal availability.

  20. MRI in diagnosis of spinal cord diseases

    International Nuclear Information System (INIS)

    Kobayashi, Naotoshi; Ono, Yuko; Kakinoki, Yoshio; Kimura, Humiko; Ebihara, Reiko; Nagayama, Takashi; Okada, Takaharu; Watanabe, Hiromi

    1985-01-01

    64 MRI studies of 57 cases of spinal cord diseases were reviewed, and following results were obtained. (1) MRI is usefull for screening method of spinal cord diseases, as CT in cerebral diseases. (2) MRI might replaces myelography in most of spinal cord disease, and more reliable informations might be obtained by MRI than in myelography in some cases, but (3) in detection of small organic changes, some technological problems are layed regarding to the image resolution of MRI. (author)

  1. MRI in osteochondrosis dissecans

    Energy Technology Data Exchange (ETDEWEB)

    Lehner, K.; Heuck, A.; Rodammer, G.; Raff, W.; Haller, W.

    1987-08-01

    The osseous manifestations of osteochondrosis dissecans are well demonstrated by conventional and computerised tomography. Beyond that, magnetic resonance imaging (MRI) is effective in evaluating the vitality and loosening of an osseous dissecate. Subchondral cavities and cartilaginous defects are detected with high acccuracy. Further, MRI seems to be a useful method in childhood to differentiate a variant irregularity of the osseous articular surface from definite osteochondrosis dissecans.

  2. Sensitivity and specificity of a new MRI method evaluating temporo-mandibular joint disc-condyle relationships: an in vivo study.

    Science.gov (United States)

    Benbelaïd, R; Fleiter, B

    2006-03-01

    The aim of this study was to evaluate sensitivity and specificity of a new method to locate temporo-mandibular joint (TMJ) disc using magnetic resonance imaging (MRI) and analyze disc-condyle relationships, in asymptomatic subjects and patients with disc displacement. Twenty-nine sagittal MRI of 16 subjects, 8 asymptomatic volunteers and 8 subjects with anterior disc displacement, were carried out during controlled opening from intercuspal position up to a 25 mm opening. Selected sections were analyzed with a graphic computerized system of coordinates. The total surface area (TS) of disc section was separated into anterior surface area (AS) and posterior surface area. Areas were determined by computer. Two trained examiners drew images at random. The reliability of AS/TS ratio index was evaluated in a previous study. AS/TS ratio sensitivity (Se) and specificity (Sp) were calculated closed mouth, 5 mm open and 25 mm open mouth. Best sensitivity (Se=0.63) and specificity (Sp=0.81) were obtained when MRI was realized with closed mouth and 25 mm open mouth. Lower sensitivity was observed when MRI was performed either with closed mouth (Se=0.54) or 25 mm open mouth (Se=0.18). Lower specificity was observed with 5 mm open mouth (Sp=0.68). In conclusion, it was confirmed as well that MRI of anterior disc displacement should be performed with closed mouth and opened mouth. Thus, further studies are required to assess disc displacement and mechanical alterations and to evaluate the risk of direct damage on TMJ tissues.

  3. Evaluation of B1 inhomogeneity effect on DCE-MRI data analysis of brain tumor patients at 3T.

    Science.gov (United States)

    Sengupta, Anirban; Gupta, Rakesh Kumar; Singh, Anup

    2017-12-02

    Dynamic-contrast-enhanced (DCE) MRI data acquired using gradient echo based sequences is affected by errors in flip angle (FA) due to transmit B 1 inhomogeneity (B 1 inh). The purpose of the study was to evaluate the effect of B 1 inh on quantitative analysis of DCE-MRI data of human brain tumor patients and to evaluate the clinical significance of B 1 inh correction of perfusion parameters (PPs) on tumor grading. An MRI study was conducted on 35 glioma patients at 3T. The patients had histologically confirmed glioma with 23 high-grade (HG) and 12 low-grade (LG). Data for B 1 -mapping, T 1 -mapping and DCE-MRI were acquired. Relative B 1 maps (B 1rel ) were generated using the saturated-double-angle method. T 1 -maps were computed using the variable flip-angle method. Post-processing was performed for conversion of signal-intensity time (S(t)) curve to concentration-time (C(t)) curve followed by tracer kinetic analysis (K trans , Ve, Vp, Kep) and first pass analysis (CBV, CBF) using the general tracer-kinetic model. DCE-MRI data was analyzed without and with B 1 inh correction and errors in PPs were computed. Receiver-operating-characteristic (ROC) analysis was performed on HG and LG patients. Simulations were carried out to understand the effect of B 1 inhomogeneity on DCE-MRI data analysis in a systematic way. S(t) curves mimicking those in tumor tissue, were generated and FA errors were introduced followed by error analysis of PPs. Dependence of FA-based errors on the concentration of contrast agent and on the duration of DCE-MRI data was also studied. Simulations were also done to obtain K trans of glioma patients at different B 1rel values and see whether grading is affected or not. Current study shows that B 1rel value higher than nominal results in an overestimation of C(t) curves as well as derived PPs and vice versa. Moreover, at same B 1rel values, errors were large for larger values of C(t). Simulation results showed that grade of patients can change

  4. Evaluation of a direct motion estimation/correction method in respiratory-gated PET/MRI with motion-adjusted attenuation.

    Science.gov (United States)

    Bousse, Alexandre; Manber, Richard; Holman, Beverley F; Atkinson, David; Arridge, Simon; Ourselin, Sébastien; Hutton, Brian F; Thielemans, Kris

    2017-06-01

    Respiratory motion compensation in PET/CT and PET/MRI is essential as motion is a source of image degradation (motion blur, attenuation artifacts). In previous work, we developed a direct method for joint image reconstruction/motion estimation (JRM) for attenuation-corrected (AC) respiratory-gated PET, which uses a single attenuation-map (μ-map). This approach was successfully implemented for respiratory-gated PET/CT, but since it relied on an accurate μ-map for motion estimation, the question of its applicability in PET/MRI is open. The purpose of this work is to investigate the feasibility of JRM in PET/MRI and to assess the robustness of the motion estimation when a degraded μ-map is used. We performed a series of JRM reconstructions from simulated PET data using a range of simulated Dixon MRI sequence derived μ-maps with wrong attenuation values in the lungs, from -100% (no attenuation) to +100% (double attenuation), as well as truncated arms. We compared the estimated motions with the one obtained from JRM in ideal conditions (no noise, true μ-map as an input). We also applied JRM on 4 patient datasets of the chest, 3 of them containing hot lesions. Patient list-mode data were gated using a principal component analysis method. We compared SUV max values of the JRM reconstructed activity images and non motion-corrected images. We also assessed the estimated motion fields by comparing the deformed JRM-reconstructed activity with individually non-AC reconstructed gates. Experiments on simulated data showed that JRM-motion estimation is robust to μ-map degradation in the sense that it produces motion fields similar to the ones obtained when using the true μ-map, regardless of the attenuation errors in the lungs (PET/MRI clinical datasets. It provides a potential alternative to existing methods where the motion fields are pre-estimated from separate MRI measurements. © 2017 University College London (UCL). Medical Physics published by Wiley Periodicals, Inc

  5. An MRI Method To Map Tumor Hypoxia Using Red Blood Cells Loaded with a pO2-Responsive Gd-Agent.

    Science.gov (United States)

    Di Gregorio, Enza; Ferrauto, Giuseppe; Gianolio, Eliana; Lanzardo, Stefania; Carrera, Carla; Fedeli, Franco; Aime, Silvio

    2015-08-25

    Hypoxia is a typical hallmark of many solid tumors and often leads to therapy resistance and the development of a more aggressive cancer phenotype. Oxygen content in tissues has been evaluated using numerous different methods for several imaging modalities, but none has yet reached the required standard of spatial and temporal resolution. Magnetic Resonance Imaging (MRI) appears to be the technique of choice and several pO2-responsive probes have been designed for it over the years. In vivo translation is often hampered in Gd-relaxation agents as it is not possible to separate effects that arise from changes in local concentration from those associated with responsive properties. A novel procedure for the MRI based assessment of hypoxia is reported herein. The method relies on the combined use of Gd-DOTP- and Gd-HPDO3A-labeled red blood cells (RBCs) where the first probe acts as a vascular oxygenation-responsive agent, while the second reports the local labeled RBC concentration in a transplanted breast tumor mouse model. The MRI assessment of oxygenation state has been validated by photoacoustic imaging and ex vivo immunofluorescence. The method refines tumor staging in preclinical models and makes possible an accurate monitoring of the relationship between oxygenation and tumor growth.

  6. How reliable is MRI in diagnosing cartilaginous lesions in patients with first and recurrent lateral patellar dislocations?

    Directory of Open Access Journals (Sweden)

    Haage Patrick

    2010-07-01

    Full Text Available Abstract Background Lateral dislocation of the patella (LPD leads to cartilaginous injuries, which have been reported to be associated with retropatellar complaints and the development of patellofemoral osteoarthritis. Therefore, the purpose of this study was to determine the reliability of MRI for cartilage diagnostics after a first and recurrent LPD. Methods After an average of 4.7 days following an acute LPD, 40 patients (21 with first LPDs and 19 with recurrent LPDs underwent standardized 1.5 Tesla MRI (sagittal T1-TSE, coronal STIR-TSE, transversal fat-suppressed PD-TSE, sagittal fat-suppressed PD-TSE. MRI grading was compared to arthroscopic assessment of the cartilage. Results Sensitivities and positive predictive values for grade 3 and 4 lesions were markedly higher in the patient group with first LPDs compared to the group with recurrent LPDs. Similarly, intra- and inter-observer agreement yielded higher kappa values in patients with first LPDs compared to those with recurrent LPDs. All grade 4 lesions affecting the subchondral bone (osteochondral defects, such as a fissuring or erosion, were correctly assessed on MRI. Conclusions This study demonstrated a comparatively good diagnostic performance for MRI in the evaluation of first and recurrent LPDs, and we therefore recommend MRI for the cartilage assessment after a LPD.

  7. Application of Sensitivity and Uncertainty Analysis Methods to a Validation Study for Weapons-Grade Mixed-Oxide Fuel

    International Nuclear Information System (INIS)

    Dunn, M.E.

    2001-01-01

    At the Oak Ridge National Laboratory (ORNL), sensitivity and uncertainty (S/U) analysis methods and a Generalized Linear Least-Squares Methodology (GLLSM) have been developed to quantitatively determine the similarity or lack thereof between critical benchmark experiments and an application of interest. The S/U and GLLSM methods provide a mathematical approach, which is less judgment based relative to traditional validation procedures, to assess system similarity and estimate the calculational bias and uncertainty for an application of interest. The objective of this paper is to gain experience with the S/U and GLLSM methods by revisiting a criticality safety evaluation and associated traditional validation for the shipment of weapons-grade (WG) MOX fuel in the MO-1 transportation package. In the original validation, critical experiments were selected based on a qualitative assessment of the MO-1 and MOX contents relative to the available experiments. Subsequently, traditional trending analyses were used to estimate the Δk bias and associated uncertainty. In this paper, the S/U and GLLSM procedures are used to re-evaluate the suite of critical experiments associated with the original MO-1 evaluation. Using the S/U procedures developed at ORNL, critical experiments that are similar to the undamaged and damaged MO-1 package are identified based on sensitivity and uncertainty analyses of the criticals and the MO-1 package configurations. Based on the trending analyses developed for the S/U and GLLSM procedures, the Δk bias and uncertainty for the most reactive MO-1 package configurations are estimated and used to calculate an upper subcritical limit (USL) for the MO-1 evaluation. The calculated bias and uncertainty from the S/U and GLLSM analyses lead to a calculational USL that supports the original validation study for the MO-1

  8. MRI methods for pulmonary ventilation and perfusion imaging; Methoden der MRT zur Ventilations- und Perfusionsbildgebung der Lunge

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin, Basel (Switzerland); Bauman, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin - Radiologische Physik, Basel (Switzerland)

    2016-02-15

    Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O{sub 2}-enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies. (orig.) [German] Die separate Beurteilung von Atemmechanik, Gasaustauschprozessen und Lungenzirkulation ist wesentlich fuer die Diagnose und Therapie von Lungenerkrankungen. Klinische Lungenfunktionstests sind aufgrund ihrer zumeist nur globalen Aussage oft nicht hinreichend spezifisch in der Differenzialdiagnostik oder eingeschraenkt sensitiv bei der

  9. MRI STUDY OF TYPES AND INCIDENCE OF INTERNAL DERANGEMENTS OF TRAUMATIC KNEE JOINT

    Directory of Open Access Journals (Sweden)

    Bomidi Sudha Rani

    2016-12-01

    Full Text Available BACKGROUND MRI has been accepted as the best imaging modality for noninvasive evaluation of knee injuries and it has proved reliable, safe and offers advantages over diagnostic arthroscopy, which is currently regarded as the reference standard for the diagnosis of internal derangements of the knee. 1 METHODS AND MATERIALS A prospective study of fifty patients who underwent MRI for the diagnosis of internal derangement of knee was conducted between the period of January 2015 to January 2016 in Government General Hospital, Kakinada. All the patients with history of knee joint pain following trauma and clinically suspected to have meniscal and ligament tears are included in the study. Patients were evaluated using GE 1.5 T MRI machine with pulsar gradient system using a sensor extremity coil. RESULTS Commonest lesion detected in our study was ACL tear followed by medial meniscal tear and medial collateral ligament injury. The most common sign of cruciate ligament injury was hyperintensity in the ligament. Grade 3 was the most common grade of meniscal tear. CONCLUSION MRI is an excellent, noninvasive, radiation free imaging modality and is unique in its ability to evaluate the internal structure as well as soft tissue delineation. Many anatomical variants can mimic a tear on MRI. MRI is an excellent noninvasive modality for imaging the knee and helps in arriving at a correct anatomical diagnosis there by guiding further management of the patient.

  10. Preliminary experience with a novel method of three-dimensional co-registration of prostate cancer digital histology and in vivo multiparametric MRI.

    Science.gov (United States)

    Orczyk, C; Rusinek, H; Rosenkrantz, A B; Mikheev, A; Deng, F-M; Melamed, J; Taneja, S S

    2013-12-01

    To assess a novel method of three-dimensional (3D) co-registration of prostate cancer digital histology and in-vivo multiparametric magnetic resonance imaging (mpMRI) image sets for clinical usefulness. A software platform was developed to achieve 3D co-registration. This software was prospectively applied to three patients who underwent radical prostatectomy. Data comprised in-vivo mpMRI [T2-weighted, dynamic contrast-enhanced weighted images (DCE); apparent diffusion coefficient (ADC)], ex-vivo T2-weighted imaging, 3D-rebuilt pathological specimen, and digital histology. Internal landmarks from zonal anatomy served as reference points for assessing co-registration accuracy and precision. Applying a method of deformable transformation based on 22 internal landmarks, a 1.6 mm accuracy was reached to align T2-weighted images and the 3D-rebuilt pathological specimen, an improvement over rigid transformation of 32% (p = 0.003). The 22 zonal anatomy landmarks were more accurately mapped using deformable transformation than rigid transformation (p = 0.0008). An automatic method based on mutual information, enabled automation of the process and to include perfusion and diffusion MRI images. Evaluation of co-registration accuracy using the volume overlap index (Dice index) met clinically relevant requirements, ranging from 0.81-0.96 for sequences tested. Ex-vivo images of the specimen did not significantly improve co-registration accuracy. This preliminary analysis suggests that deformable transformation based on zonal anatomy landmarks is accurate in the co-registration of mpMRI and histology. Including diffusion and perfusion sequences in the same 3D space as histology is essential further clinical information. The ability to localize cancer in 3D space may improve targeting for image-guided biopsy, focal therapy, and disease quantification in surveillance protocols. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  11. Task-Related Edge Density (TED)-A New Method for Revealing Dynamic Network Formation in fMRI Data of the Human Brain.

    Science.gov (United States)

    Lohmann, Gabriele; Stelzer, Johannes; Zuber, Verena; Buschmann, Tilo; Margulies, Daniel; Bartels, Andreas; Scheffler, Klaus

    2016-01-01

    The formation of transient networks in response to external stimuli or as a reflection of internal cognitive processes is a hallmark of human brain function. However, its identification in fMRI data of the human brain is notoriously difficult. Here we propose a new method of fMRI data analysis that tackles this problem by considering large-scale, task-related synchronisation networks. Networks consist of nodes and edges connecting them, where nodes correspond to voxels in fMRI data, and the weight of an edge is determined via task-related changes in dynamic synchronisation between their respective times series. Based on these definitions, we developed a new data analysis algorithm that identifies edges that show differing levels of synchrony between two distinct task conditions and that occur in dense packs with similar characteristics. Hence, we call this approach "Task-related Edge Density" (TED). TED proved to be a very strong marker for dynamic network formation that easily lends itself to statistical analysis using large scale statistical inference. A major advantage of TED compared to other methods is that it does not depend on any specific hemodynamic response model, and it also does not require a presegmentation of the data for dimensionality reduction as it can handle large networks consisting of tens of thousands of voxels. We applied TED to fMRI data of a fingertapping and an emotion processing task provided by the Human Connectome Project. TED revealed network-based involvement of a large number of brain areas that evaded detection using traditional GLM-based analysis. We show that our proposed method provides an entirely new window into the immense complexity of human brain function.

  12. Task-Related Edge Density (TED-A New Method for Revealing Dynamic Network Formation in fMRI Data of the Human Brain.

    Directory of Open Access Journals (Sweden)

    Gabriele Lohmann

    Full Text Available The formation of transient networks in response to external stimuli or as a reflection of internal cognitive processes is a hallmark of human brain function. However, its identification in fMRI data of the human brain is notoriously difficult. Here we propose a new method of fMRI data analysis that tackles this problem by considering large-scale, task-related synchronisation networks. Networks consist of nodes and edges connecting them, where nodes correspond to voxels in fMRI data, and the weight of an edge is determined via task-related changes in dynamic synchronisation between their respective times series. Based on these definitions, we developed a new data analysis algorithm that identifies edges that show differing levels of synchrony between two distinct task conditions and that occur in dense packs with similar characteristics. Hence, we call this approach "Task-related Edge Density" (TED. TED proved to be a very strong marker for dynamic network formation that easily lends itself to statistical analysis using large scale statistical inference. A major advantage of TED compared to other methods is that it does not depend on any specific hemodynamic response model, and it also does not require a presegmentation of the data for dimensionality reduction as it can handle large networks consisting of tens of thousands of voxels. We applied TED to fMRI data of a fingertapping and an emotion processing task provided by the Human Connectome Project. TED revealed network-based involvement of a large number of brain areas that evaded detection using traditional GLM-based analysis. We show that our proposed method provides an entirely new window into the immense complexity of human brain function.

  13. Task-Related Edge Density (TED)—A New Method for Revealing Dynamic Network Formation in fMRI Data of the Human Brain

    Science.gov (United States)

    Lohmann, Gabriele; Stelzer, Johannes; Zuber, Verena; Buschmann, Tilo; Margulies, Daniel; Bartels, Andreas; Scheffler, Klaus

    2016-01-01

    The formation of transient networks in response to external stimuli or as a reflection of internal cognitive processes is a hallmark of human brain function. However, its identification in fMRI data of the human brain is notoriously difficult. Here we propose a new method of fMRI data analysis that tackles this problem by considering large-scale, task-related synchronisation networks. Networks consist of nodes and edges connecting them, where nodes correspond to voxels in fMRI data, and the weight of an edge is determined via task-related changes in dynamic synchronisation between their respective times series. Based on these definitions, we developed a new data analysis algorithm that identifies edges that show differing levels of synchrony between two distinct task conditions and that occur in dense packs with similar characteristics. Hence, we call this approach “Task-related Edge Density” (TED). TED proved to be a very strong marker for dynamic network formation that easily lends itself to statistical analysis using large scale statistical inference. A major advantage of TED compared to other methods is that it does not depend on any specific hemodynamic response model, and it also does not require a presegmentation of the data for dimensionality reduction as it can handle large networks consisting of tens of thousands of voxels. We applied TED to fMRI data of a fingertapping and an emotion processing task provided by the Human Connectome Project. TED revealed network-based involvement of a large number of brain areas that evaded detection using traditional GLM-based analysis. We show that our proposed method provides an entirely new window into the immense complexity of human brain function. PMID:27341204

  14. Optimizing signal intensity correction during evaluation of hepatic parenchymal enhancement on gadoxetate disodium-enhanced MRI: Comparison of three methods

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Minori, E-mail: onoda@radt.med.kindai.ac.jp [Department of Radiological Technology, Kinki University Hospital, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Hyodo, Tomoko, E-mail: neneth@m.ehime-u.ac.jp [Department of Radiology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Murakami, Takamichi, E-mail: murakami@med.kindai.ac.jp [Department of Radiology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Okada, Masahiro, E-mail: okada777@med.u-ryukyu.ac.jp [Department of Radiology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Uto, Tatsuro, E-mail: chuho@med.kindai.ac.jp [Department of Radiological Technology, Kinki University Hospital, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Hori, Masatoshi, E-mail: mhori@radiol.med.osaka-u.ac.jp [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Miyati, Tosiaki, E-mail: ramiyati@mhs.mp.kanazawa-u.ac.jp [Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan)

    2015-03-15

    Highlights: •Signal intensity is often used to evaluate hepatic enhancement with Gd-EOB-DTPA in the hepatobiliary phase. •Comparison of uncorrected signal intensity with T{sub 1} value revealed signal intensity instability. •Measurement of uncorrected liver SI or SNR often yields erroneous results on late-phase gadoxetate MRI due to shimming and other optimization techniques. •Signal intensity corrected by scale and rescale slope from DICOM data gave comparable results. -- Abstract: Objective: To compare signal intensity (SI) correction using scale and rescale slopes with SI correction using SIs of spleen and muscle for quantifying multiphase hepatic contrast enhancement with Gd-EOB-DTPA by assessing their correlation with T{sub 1} values generated from Look-Locker turbo-field-echo (LL-TFE) sequence data (ER-T{sub 1}). Materials and methods: Thirty patients underwent Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in this prospective clinical study. For each patient, breath-hold T{sub 1}-weighted fat-suppressed three-dimensional (3D) gradient echo sequences (e-THRIVE) were acquired before and 2 (first phase), 10 (second phase), and 20 min (third phase) after intravenous Gd-EOB-DTPA. Look-Locker turbo-field-echo (LL-TFE) sequences were acquired before and 1.5 (first phase), 8 (second phase), and 18 min (third phase) postcontrast. The liver parenchyma enhancement ratios (ER) of each phase were calculated using the SI from e-THRIVE sequences (ER-SI) and the T{sub 1} values generated from LL-TFE sequence data (ER-T{sub 1}) respectively. ER-SIs were calculated in three ways: (1) comparing with splenic SI (ER-SI-s), (2) comparing with muscle SI (ER-SI-m), (3) using scale and rescale slopes obtained from DICOM headers (ER-SI-c), to eliminate the effects of receiver gain and scaling. For each of the first, second and third phases, correlation and agreement were assessed between each ER-SI and ER-T{sub 1}. Results: In the first phase, all ER-SIs correlated

  15. MRI features of chondroblastoma

    International Nuclear Information System (INIS)

    Cheng Xiaoguang; Liu Xia; Cheng Kebin; Liu Wei

    2009-01-01

    Objective: To evaluate the MR imaging features of chondroblastoma. Methods: MRI examinations of 20 patients with histological proven chondmblastoma were reviewed retrospectively. The MRI findings of chondroblastoma including the signal intensity, the shape, the growth patterns, and the surrounding bone marrow edema and the adjacent soft tissue edema, the periosteal reaction, the adjacent joint effusion were analyzed. Results: All 20 cases demonstrated heterogeneous MR signal intensity on T 1 WI and T 2 WI images and showed lobular margins. Sixteen cases demonstrated expansive growth patterns. Surrounding bone marrow edema was found in 18 cases and adjacent soft tissue edema in 14 cases. Periosteal reaction was identified in 6 cases. In 7 cases the tumor extended to adjacent soft tissue. Adjacent joint effusion was visible on MRI in 6 cases. Conclusion: Heterogeneous signal intensity, lobular margins and expansive growth pattern, adjacent bone marrow and soft tissue edema were the common features of chondroblastoma on MRI. (authors)

  16. Fast CSF MRI for brain segmentation; Cross-validation by comparison with 3D T1-based brain segmentation methods

    NARCIS (Netherlands)

    van der Kleij, Lisa A; de Bresser, Jeroen; Hendrikse, Jeroen; Siero, Jeroen C W; Petersen, Esben T; De Vis, Jill B

    2018-01-01

    OBJECTIVE: In previous work we have developed a fast sequence that focusses on cerebrospinal fluid (CSF) based on the long T2 of CSF. By processing the data obtained with this CSF MRI sequence, brain parenchymal volume (BPV) and intracranial volume (ICV) can be automatically obtained. The aim of

  17. MRI diagnosis of meningovascular neurosyphilis

    International Nuclear Information System (INIS)

    Chen Shuang; Qian Jianguo; Feng Xiaoyuan

    2005-01-01

    Objective: To evaluate the value and limitation of MRI in the diagnosis of meningovascular neurosyphilis. Methods: Five cases of neurosyphilis confirmed by clinical history/laboratory were examined with MRI (3 plain MRI, 2 enhanced MRI). The results of blood and CSF TPPA/RPR were positive and HIV was negative. Results: Abnormal signals were demonstrated in the temporal lobe in 3 cases, and infarction was revealed in the basal ganglion and periventricular white matter in another 2 cases. There was no marked contrast enhancement in the 2 cases. Conclusion: Meningovascular neurosyphilis has no characteristic features on MRI, but MRI is an effective method in delineating the size, range, and characters of neurosyphilis, and it is also an useful modality to follow-up after antibiotic therapy. (authors)

  18. MRI Primer

    International Nuclear Information System (INIS)

    Oldendorf, W.; Oldendorf, W. Jr.

    1991-01-01

    Designed for studies, radiologists, and clinicians at all levels of training, this book provides a basic introduction to the principles, physics, and instrumentation of magnetic resonance imaging. The fundamental concepts that are essential for the optimal clinical use of MRI are thoroughly explained in easily accessible terms. To facilitate the reader's comprehension, the material is presented nonmathematically, using no equations and a minimum of symbols and abbreviations. MRI Primer presents a clear account of the phenomenon of nuclear magnetic resonance and the use of gradient magnetic fields to create clinically useful images of cross-sectional slices. Close attention is given to the magnetization vector as a means of expressing nuclear behavior, the role of T 1 and T 2 weighing in imaging, the use of contrast agents, and the pulse sequences most often used in clinical practice, as well as to the relative capabilities and limitations of MRI and CT. The basic hardware components of an MRI scanner are described in detail. Sample MRI scans illustrate how MRI characterizes tissue. An appendix provides a brief introduction to quantum processes in MRI

  19. Grade 11 Students' Interconnected Use of Conceptual Knowledge, Procedural Skills, and Strategic Competence in Algebra: A Mixed Method Study of Error Analysis

    Science.gov (United States)

    Egodawatte, Gunawardena; Stoilescu, Dorian

    2015-01-01

    The purpose of this mixed-method study was to investigate grade 11 university/college stream mathematics students' difficulties in applying conceptual knowledge, procedural skills, strategic competence, and algebraic thinking in solving routine (instructional) algebraic problems. A standardized algebra test was administered to thirty randomly…

  20. The TIMSS Videotape Classroom Study: Methods and Findings from an Exploratory Research Project on Eighth-Grade Mathematics Instruction in Germany, Japan, and the United States.

    Science.gov (United States)

    Stigler, James W.; Gonzales, Patrick; Kawanaka, Takako; Knoll, Steffen; Serrano, Ana

    1999-01-01

    Describes the methods and preliminary findings of the Videotape Classroom Study, a video survey of eighth-grade mathematics lessons in Germany, Japan, and the United States. Part of the Third International Mathematics and Science study, this research project is the first study of videotaped records from national probability samples. (SLD)

  1. MO-C-17A-02: A Novel Method for Evaluating Hepatic Stiffness Based On 4D-MRI and Deformable Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Cui, T [Duke University, Durham, NC (United States); Liang, X [Duke Unversity, Durham, NC (United States); Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J [Duke University Medical Center, Durham, NC (United States)

    2014-06-15

    Purpose: Quantitative imaging of hepatic stiffness has significant potential in radiation therapy, ranging from treatment planning to response assessment. This study aims to develop a novel, noninvasive method to quantify liver stiffness with 3D strains liver maps using 4D-MRI and deformable image registration (DIR). Methods: Five patients with liver cancer were imaged with an institutionally developed 4D-MRI technique under an IRB-approved protocol. Displacement vector fields (DVFs) across the liver were generated via DIR of different phases of 4D-MRI. Strain tensor at each voxel of interest (VOI) was computed from the relative displacements between the VOI and each of the six adjacent voxels. Three principal strains (E{sub 1}, E{sub 2} and E{sub 3}) of the VOI were derived as the eigenvalue of the strain tensor, which represent the magnitudes of the maximum and minimum stretches. Strain tensors for two regions of interest (ROIs) were calculated and compared for each patient, one within the tumor (ROI{sub 1}) and the other in normal liver distant from the heart (ROI{sub 2}). Results: 3D strain maps were successfully generated fort each respiratory phase of 4D-MRI for all patients. Liver deformations induced by both respiration and cardiac motion were observed. Differences in strain values adjacent to the distant from the heart indicate significant deformation caused by cardiac expansion during diastole. The large E{sub 1}/E{sub 2} (∼2) and E{sub 1}/E{sub 2} (∼10) ratios reflect the predominance of liver deformation in the superior-inferior direction. The mean E{sub 1} in ROI{sub 1} (0.12±0.10) was smaller than in ROI{sub 2} (0.15±0.12), reflecting a higher degree of stiffness of the cirrhotic tumor. Conclusion: We have successfully developed a novel method for quantitatively evaluating regional hepatic stiffness based on DIR of 4D-MRI. Our initial findings indicate that liver strain is heterogeneous, and liver tumors may have lower principal strain values

  2. MO-C-17A-02: A Novel Method for Evaluating Hepatic Stiffness Based On 4D-MRI and Deformable Image Registration

    International Nuclear Information System (INIS)

    Cui, T; Liang, X; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J

    2014-01-01

    Purpose: Quantitative imaging of hepatic stiffness has significant potential in radiation therapy, ranging from treatment planning to response assessment. This study aims to develop a novel, noninvasive method to quantify liver stiffness with 3D strains liver maps using 4D-MRI and deformable image registration (DIR). Methods: Five patients with liver cancer were imaged with an institutionally developed 4D-MRI technique under an IRB-approved protocol. Displacement vector fields (DVFs) across the liver were generated via DIR of different phases of 4D-MRI. Strain tensor at each voxel of interest (VOI) was computed from the relative displacements between the VOI and each of the six adjacent voxels. Three principal strains (E 1 , E 2 and E 3 ) of the VOI were derived as the eigenvalue of the strain tensor, which represent the magnitudes of the maximum and minimum stretches. Strain tensors for two regions of interest (ROIs) were calculated and compared for each patient, one within the tumor (ROI 1 ) and the other in normal liver distant from the heart (ROI 2 ). Results: 3D strain maps were successfully generated fort each respiratory phase of 4D-MRI for all patients. Liver deformations induced by both respiration and cardiac motion were observed. Differences in strain values adjacent to the distant from the heart indicate significant deformation caused by cardiac expansion during diastole. The large E 1 /E 2 (∼2) and E 1 /E 2 (∼10) ratios reflect the predominance of liver deformation in the superior-inferior direction. The mean E 1 in ROI 1 (0.12±0.10) was smaller than in ROI 2 (0.15±0.12), reflecting a higher degree of stiffness of the cirrhotic tumor. Conclusion: We have successfully developed a novel method for quantitatively evaluating regional hepatic stiffness based on DIR of 4D-MRI. Our initial findings indicate that liver strain is heterogeneous, and liver tumors may have lower principal strain values than normal liver. Thorough validation of our method is

  3. An innovation on high-grade CNC machines tools for B-spline curve method of high-speed interpolation arithmetic

    Science.gov (United States)

    Zhang, Wanjun; Gao, Shanping; Cheng, Xiyan; Zhang, Feng

    2017-04-01

    A novel on high-grade CNC machines tools for B Spline curve method of High-speed interpolation arithmetic is introduced. In the high-grade CNC machines tools CNC system existed the type value points is more trouble, the control precision is not strong and so on, In order to solve this problem. Through specific examples in matlab7.0 simulation result showed that that the interpolation error significantly reduced, the control precision is improved markedly, and satisfy the real-time interpolation of high speed, high accuracy requirements.

  4. A new approach combining different MRI methods to provide detailed view on 2 swelling dynamics of xanthan tablets influencing drug release at different pH and 3 ionic strength

    OpenAIRE

    Sepe, Ana; Mikac, Urška; Baumgartner, Saša; Kristl, Julijana

    2015-01-01

    The key element in drug release from hydrophilic matrix tablets is the gel layer that regulates the penetration of water and controls drug dissolution and diffusion. We have selected magnetic resonance imaging (MRI) as the method of choice for visualizing the dynamic processes occurring during the swelling of xanthan tablets in a variety of media. The aims were (i) to develop a new method using MRI for accurate determination of penetration, swelling and erosion fronts, (ii) to investigate the...

  5. MRI findings and correlation with pathological features in breast phyllodes tumor

    International Nuclear Information System (INIS)

    Shen Xigang; Tan Hongna; Peng Weijun; Li Ruimin; Gu Yajia; Huang Dan; Mao Jian; Zhou Liangping

    2011-01-01

    Objective: To study the MR Imaging features of breast phyllodes tumor (PT), and to correlate it with pathological results. Method: Clinical and MRI findings were retrospectively reviewed in twenty-seven women with 28 PTs lesions confirmed by surgical pathology. Statistical analyses were one-way ANOVA for size analysis, Fisher exact test for analysis of MR appearances and Spearman correlation to study the relationship between MRI findings and BI-RADS categories. Results: (1) The histologic findings were benign, borderline and malignant PTs in 14.3% (4/28), 53.6% (15/28) and 32.1% (9/28) of lesions, respectively. (2) The mean maximum-diameter were (6.4±3.9) cm, (5.7±2.2) cm in borderline type and (4.8±1.8) cm in benign type respectively. The results showed differences in lesion's size among the three type (F= 287.541, P=0.000), especially between malignant and benign type (P=0.033). (3) Internal non-enhanced septation and silt-like changes on enhanced images, as well as time-signal curve on MRI correlated significantly with the histological grade (P<0.05). (4) If the category BI-RADS ≥ 4a was considered to be a suspicious sign for malignant lesion, the diagnostic accuracy of MRI would be 96.4% (27/28), and the BI-RADS category of the MRI could reflect the PT's histological grade with a low correlation coefficient (r=0.382, P=0.045). Conclusion: The findings of PT on MRI have some characteristics, with tumor size and several MRI features correlating with the histological grade of breast PT. (authors)

  6. Enhancing the discrimination accuracy between metastases, gliomas and meningiomas on brain MRI by volumetric textural features and ensemble pattern recognition methods.

    Science.gov (United States)

    Georgiadis, Pantelis; Cavouras, Dionisis; Kalatzis, Ioannis; Glotsos, Dimitris; Athanasiadis, Emmanouil; Kostopoulos, Spiros; Sifaki, Koralia; Malamas, Menelaos; Nikiforidis, George; Solomou, Ekaterini

    2009-01-01

    Three-dimensional (3D) texture analysis of volumetric brain magnetic resonance (MR) images has been identified as an important indicator for discriminating among different brain pathologies. The purpose of this study was to evaluate the efficiency of 3D textural features using a pattern recognition system in the task of discriminating benign, malignant and metastatic brain tissues on T1 postcontrast MR imaging (MRI) series. The dataset consisted of 67 brain MRI series obtained from patients with verified and untreated intracranial tumors. The pattern recognition system was designed as an ensemble classification scheme employing a support vector machine classifier, specially modified in order to integrate the least squares features transformation logic in its kernel function. The latter, in conjunction with using 3D textural features, enabled boosting up the performance of the system in discriminating metastatic, malignant and benign brain tumors with 77.14%, 89.19% and 93.33% accuracy, respectively. The method was evaluated using an external cross-validation process; thus, results might be considered indicative of the generalization performance of the system to "unseen" cases. The proposed system might be used as an assisting tool for brain tumor characterization on volumetric MRI series.

  7. Head MRI

    Science.gov (United States)

    ... hearing aids Pins, hairpins, metal zippers, and similar metallic items Removable dental work How the Test will ... an MRI can make heart pacemakers and other implants not work as well. It can also cause ...

  8. Pediatric MRI

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIH Study of Normal Brain Development is a longitudinal study using anatomical MRI, diffusion tensor imaging (DTI), and MR spectroscopy (MRS) to map pediatric...

  9. Automatic cardiac cycle determination directly from EEG-fMRI data by multi-scale peak detection method.

    Science.gov (United States)

    Wong, Chung-Ki; Luo, Qingfei; Zotev, Vadim; Phillips, Raquel; Chan, Kam Wai Clifford; Bodurka, Jerzy

    2018-03-31

    In simultaneous EEG-fMRI, identification of the period of cardioballistic artifact (BCG) in EEG is required for the artifact removal. Recording the electrocardiogram (ECG) waveform during fMRI is difficult, often causing inaccurate period detection. Since the waveform of the BCG extracted by independent component analysis (ICA) is relatively invariable compared to the ECG waveform, we propose a multiple-scale peak-detection algorithm to determine the BCG cycle directly from the EEG data. The algorithm first extracts the high contrast BCG component from the EEG data by ICA. The BCG cycle is then estimated by band-pass filtering the component around the fundamental frequency identified from its energy spectral density, and the peak of BCG artifact occurrence is selected from each of the estimated cycle. The algorithm is shown to achieve a high accuracy on a large EEG-fMRI dataset. It is also adaptive to various heart rates without the needs of adjusting the threshold parameters. The cycle detection remains accurate with the scan duration reduced to half a minute. Additionally, the algorithm gives a figure of merit to evaluate the reliability of the detection accuracy. The algorithm is shown to give a higher detection accuracy than the commonly used cycle detection algorithm fmrib_qrsdetect implemented in EEGLAB. The achieved high cycle detection accuracy of our algorithm without using the ECG waveforms makes possible to create and automate pipelines for processing large EEG-fMRI datasets, and virtually eliminates the need for ECG recordings for BCG artifact removal. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Integrating atlas and graph cut methods for right ventricle blood-pool segmentation from cardiac cine MRI

    Science.gov (United States)

    Dangi, Shusil; Linte, Cristian A.

    2017-03-01

    Segmentation of right ventricle from cardiac MRI images can be used to build pre-operative anatomical heart models to precisely identify regions of interest during minimally invasive therapy. Furthermore, many functional parameters of right heart such as right ventricular volume, ejection fraction, myocardial mass and thickness can also be assessed from the segmented images. To obtain an accurate and computationally efficient segmentation of right ventricle from cardiac cine MRI, we propose a segmentation algorithm formulated as an energy minimization problem in a graph. Shape prior obtained by propagating label from an average atlas using affine registration is incorporated into the graph framework to overcome problems in ill-defined image regions. The optimal segmentation corresponding to the labeling with minimum energy configuration of the graph is obtained via graph-cuts and is iteratively refined to produce the final right ventricle blood pool segmentation. We quantitatively compare the segmentation results obtained from our algorithm to the provided gold-standard expert manual segmentation for 16 cine-MRI datasets available through the MICCAI 2012 Cardiac MR Right Ventricle Segmentation Challenge according to several similarity metrics, including Dice coefficient, Jaccard coefficient, Hausdorff distance, and Mean absolute distance error.

  11. Concurrent fNIRS-fMRI measurement to validate a method for separating deep and shallow fNIRS signals by using multidistance optodes

    Science.gov (United States)

    Funane, Tsukasa; Sato, Hiroki; Yahata, Noriaki; Takizawa, Ryu; Nishimura, Yukika; Kinoshita, Akihide; Katura, Takusige; Atsumori, Hirokazu; Fukuda, Masato; Kasai, Kiyoto; Koizumi, Hideaki; Kiguchi, Masashi

    2015-01-01

    Abstract. It has been reported that a functional near-infrared spectroscopy (fNIRS) signal can be contaminated by extracerebral contributions. Many algorithms using multidistance separations to address this issue have been proposed, but their spatial separation performance has rarely been validated with simultaneous measurements of fNIRS and functional magnetic resonance imaging (fMRI). We previously proposed a method for discriminating between deep and shallow contributions in fNIRS signals, referred to as the multidistance independent component analysis (MD-ICA) method. In this study, to validate the MD-ICA method from the spatial aspect, multidistance fNIRS, fMRI, and laser-Doppler-flowmetry signals were simultaneously obtained for 12 healthy adult males during three tasks. The fNIRS signal was separated into deep and shallow signals by using the MD-ICA method, and the correlation between the waveforms of the separated fNIRS signals and the gray matter blood oxygenation level–dependent signals was analyzed. A three-way analysis of variance (signal depth×Hb kind×task) indicated that the main effect of fNIRS signal depth on the correlation is significant [F(1,1286)=5.34, pdeep and shallow signals, and the accuracy and reliability of the fNIRS signal will be improved with the method. PMID:26157983

  12. A quick in-situ estimating method for grading stone products as radiation protection standard of building materials

    International Nuclear Information System (INIS)

    Nanping, Wang; Shengli, Hou; Yexun, Chen

    2002-01-01

    Natural stone is word-widely used as building and decorating material, which is made of marble, granite or other kinds of rocks. Normally they are cut into rectangle with 20 mm thickness. In order to grade small size stone plank as radioactive protection standard (China Standard GB6566-2001), a quick in-situ technique and a special kind of portable -ray detector is developed. The detector is made of NaI (Tl) ( 30x50mm) with a shield (Model ZDD3901, China Patent No. 992080045). The difference modeling was established for small-size stone planks grading. About 96.3% stone plank samples which size are more than 300x300x20 mm could be determined radiation levels by in-situ techniques, by which the grading results (A, B or C) are coincided with quantity analysis in lab

  13. A quick in-situ estimating method for grading stone products as radiation protection standard of building materials

    Energy Technology Data Exchange (ETDEWEB)

    Nanping, Wang; Shengli, Hou; Yexun, Chen [China Univ. of Geosciences, Bijing (China)

    2002-07-01

    Natural stone is word-widely used as building and decorating material, which is made of marble, granite or other kinds of rocks. Normally they are cut into rectangle with 20 mm thickness. In order to grade small size stone plank as radioactive protection standard (China Standard GB6566-2001), a quick in-situ technique and a special kind of portable -ray detector is developed. The detector is made of NaI (Tl) ( 30x50mm) with a shield (Model ZDD3901, China Patent No. 992080045). The difference modeling was established for small-size stone planks grading. About 96.3% stone plank samples which size are more than 300x300x20 mm could be determined radiation levels by in-situ techniques, by which the grading results (A, B or C) are coincided with quantity analysis in lab.

  14. MRI of the fetal abdomen

    International Nuclear Information System (INIS)

    Hoermann, M.; Brugger, P.C.; Witzani, L.; Prayer, D.

    2006-01-01

    Magnetic resonance imaging (MRI) is an important diagnostic component for central nervous system and thoracic diseases during fetal development. Although ultrasound remains the method of choice for observing the fetus during pregnancy, fetal MRI is being increasingly used as an additional technique for the accurate diagnosis of abdominal diseases. Recent publications confirm the value of MRI in the diagnosis of fetal gastrointestinal tract and urogenital system diseases. The following report provides an overview of MRI-examination techniques for the most frequent diseases of the abdomen. (orig.) [de

  15. MRI as an accurate tool for the diagnosis and characterization of different knee joint meniscal injuries

    Directory of Open Access Journals (Sweden)

    Ayman F. Ahmed

    2017-12-01

    Conclusion: MRI of the knee will give the orthopedic surgeons ability to select suitable treatment and arthroscopic interference for their patients. MRI has high accuracy in meniscal tears diagnosis allowing accurate grading of them.

  16. Analysis of chronic aortic regurgitation by 2D and 3D echocardiography and cardiac MRI

    Science.gov (United States)

    Stoebe, Stephan; Metze, Michael; Jurisch, Daniel; Tayal, Bhupendar; Solty, Kilian; Laufs, Ulrich; Pfeiffer, Dietrich; Hagendorff, Andreas

    2018-01-01

    Purpose The study compares the feasibility of the quantitative volumetric and semi-quantitative approach for quantification of chronic aortic regurgitation (AR) using different imaging modalities. Methods Left ventricular (LV) volumes, regurgitant volumes (RVol) and regurgitant fractions (RF) were assessed retrospectively by 2D, 3D echocardiography and cMRI in 55 chronic AR patients. Semi-quantitative parameters were assessed by 2D echocardiography. Results 22 (40%) patients had mild, 25 (46%) moderate and 8 (14%) severe AR. The quantitative volumetric approach was feasible using 2D, 3D echocardiography and cMRI, whereas the feasibility of semi-quantitative parameters varied considerably. LV volume (LVEDV, LVESV, SVtot) analyses showed good correlations between the different imaging modalities, although significantly increased LV volumes were assessed by cMRI. RVol was significantly different between 2D/3D echocardiography and 2D echocardiography/cMRI but was not significantly different between 3D echocardiography/cMRI. RF was not statistically different between 2D echocardiography/cMRI and 3D echocardiography/cMRI showing poor correlations (r echocardiography and 2D echocardiography/cMRI and good agreement was observed between 3D echocardiography/cMRI. Conclusion Semi-quantitative parameters are difficult to determine by 2D echocardiography in clinical routine. The quantitative volumetric RF assessment seems to be feasible and can be discussed as an alternative approach in chronic AR. However, RVol and RF did not correlate well between the different imaging modalities. The best agreement for grading of AR severity by RF was observed between 3D echocardiography and cMRI. LV volumes can be verified by different approaches and different imaging modalities. PMID:29519957

  17. TU-CD-BRA-04: Evaluation of An Atlas-Based Segmentation Method for Prostate and Peripheral Zone Regions On MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, AS; Piper, J; Curry, K; Swallen, A [MIM Software Inc., Cleveland, OH (United States); Padgett, K; Pollack, A; Stoyanova, RS [University of Miami, Miami, FL (United States)

    2015-06-15

    Purpose: Prostate MRI plays an important role in diagnosis, biopsy guidance, and therapy planning for prostate cancer. Prostate MRI contours can be used to aid in image fusion for ultrasound biopsy guidance and delivery of radiation. Our goal in this study is to evaluate an automatic atlas-based segmentation method for generating prostate and peripheral zone (PZ) contours on MRI. Methods: T2-weighted MRIs were acquired on 3T-Discovery MR750 System (GE, Milwaukee). The Volumes of Interest (VOIs): prostate and PZ were outlined by an expert radiation oncologist and used to create an atlas library for atlas-based segmentation. The atlas-segmentation accuracy was evaluated using a leave-one-out analysis. The method involved automatically finding the atlas subject that best matched the test subject followed by a normalized intensity-based free-form deformable registration of the atlas subject to the test subject. The prostate and PZ contours were transformed to the test subject using the same deformation. For each test subject the three best matches were used and the final contour was combined using Majority Vote. The atlas-segmentation process was fully automatic. Dice similarity coefficients (DSC) and mean Hausdorff values were used for comparison. Results: VOIs contours were available for 28 subjects. For the prostate, the atlas-based segmentation method resulted in an average DSC of 0.88+/−0.08 and a mean Hausdorff distance of 1.1+/−0.9mm. The number of patients (#) in DSC ranges are as follows: 0.60–0.69(1), 0.70–0.79(2), 0.80–0.89(13), >0.89(11). For the PZ, the average DSC was 0.72+/−0.17 and average Hausdorff of 0.9+/−0.9mm. The number of patients (#) in DSC ranges are as follows: <0.60(4), 0.60–0.69(6), 0.70–0.79(7), 0.80–0.89(9), >0.89(1). Conclusion: The MRI atlas-based segmentation method achieved good results for both the whole prostate and PZ compared to expert defined VOIs. The technique is fast, fully automatic, and has the potential

  18. TU-CD-BRA-04: Evaluation of An Atlas-Based Segmentation Method for Prostate and Peripheral Zone Regions On MRI

    International Nuclear Information System (INIS)

    Nelson, AS; Piper, J; Curry, K; Swallen, A; Padgett, K; Pollack, A; Stoyanova, RS

    2015-01-01

    Purpose: Prostate MRI plays an important role in diagnosis, biopsy guidance, and therapy planning for prostate cancer. Prostate MRI contours can be used to aid in image fusion for ultrasound biopsy guidance and delivery of radiation. Our goal in this study is to evaluate an automatic atlas-based segmentation method for generating prostate and peripheral zone (PZ) contours on MRI. Methods: T2-weighted MRIs were acquired on 3T-Discovery MR750 System (GE, Milwaukee). The Volumes of Interest (VOIs): prostate and PZ were outlined by an expert radiation oncologist and used to create an atlas library for atlas-based segmentation. The atlas-segmentation accuracy was evaluated using a leave-one-out analysis. The method involved automatically finding the atlas subject that best matched the test subject followed by a normalized intensity-based free-form deformable registration of the atlas subject to the test subject. The prostate and PZ contours were transformed to the test subject using the same deformation. For each test subject the three best matches were used and the final contour was combined using Majority Vote. The atlas-segmentation process was fully automatic. Dice similarity coefficients (DSC) and mean Hausdorff values were used for comparison. Results: VOIs contours were available for 28 subjects. For the prostate, the atlas-based segmentation method resulted in an average DSC of 0.88+/−0.08 and a mean Hausdorff distance of 1.1+/−0.9mm. The number of patients (#) in DSC ranges are as follows: 0.60–0.69(1), 0.70–0.79(2), 0.80–0.89(13), >0.89(11). For the PZ, the average DSC was 0.72+/−0.17 and average Hausdorff of 0.9+/−0.9mm. The number of patients (#) in DSC ranges are as follows: 0.89(1). Conclusion: The MRI atlas-based segmentation method achieved good results for both the whole prostate and PZ compared to expert defined VOIs. The technique is fast, fully automatic, and has the potential to provide significant time savings for prostate VOI

  19. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... can also provide functional information (fMRI) in selected cases. MR images of the brain and other cranial structures are clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many conditions, ...

  1. Characterization of glial tumors in PET/CT 18F-dopa and in perfusion MRI

    International Nuclear Information System (INIS)

    Nioche, Christophe

    2011-01-01

    MRI provides morphological information about a tumour, as well as information regarding its micro-vascularisation of the tumour. In PET/CT, accumulation of 18 F-Dopa in tumour cells results from the metabolic activity greater than that of healthy tissues.We studied 28 gliomas for which we analysed data from MRI and PET/CT. A registration method has been developed to combine information from both PET and MRI and to extract volumes of interest consistent with the information included in the two modalities. In these volumes, the tumour compartment and normal tissue compartment were identified using a Gaussian mixture model. Parameters from PET or MRI data were then calculated in these compartments. ROC analyses combined with linear discriminant analyses were used to assess whether joint observation of standardized uptake value (SUVmax) and relative Cerebral Blood Volume (rCBV) or of relative rk1 and rCBV could distinguish between low grade and high grade tumours. We found that using this joint analysis, 82% of high-grade tumors and 70% of low grade tumors were correctly classified (AUC of 0.88 for [SUVmax, rCBV] and of 0.92 for [rk1, rCBV]). Considering the combined information from [SUVmax, rCBV], the sensitivity for detecting high-grade tumors was 95% with a specificity of 60%. The negative predictive value was 52% for a positive predictive value of 95%. Similarly, considering the combined information from [rk1, rCBV], we also obtain a specificity of 60% associated with a 95% sensitivity for detecting high-grade tumors, with a negative predictive value of 60% and positive predictive value of 95%. Our work shows that joint analysis of information from microvascular and metabolic is possible by combining PET and MR imaging data. However, we found that, in our patient population, the microvascular information obtained through MR did not achieve better discrimination than the metabolic information derived from PET only. (author)

  2. Teachers' Motivating Methods to Support Thai Ninth Grade Students' Levels of Motivation and Learning in Mathematics Classrooms

    Science.gov (United States)

    Nenthien, Sansanee; Loima, Jyrki

    2016-01-01

    The aims of this qualitative research were to investigate the level of motivation and learning of ninth grade students in mathematics classrooms in Thailand and to reveal how the teachers supported students' levels of motivation and learning. The participants were 333 students and 12 teachers in 12 mathematics classrooms from four regions of…

  3. The Correlation between Academic Achievements, Self-Esteem and Motivation of Female Seventh Grade Students: A Mixed Methods Approach

    Science.gov (United States)

    Henman, Karen

    2010-01-01

    During the early grades, female students generally display enthusiasm for learning science. As these same students go though school, however, their level of motivation changes. Once female students reach high school, many lack the confidence to take chemistry and physics. Then, in college they lack the background necessary to major in chemistry,…

  4. Automated fibroglandular tissue segmentation and volumetric density estimation in breast MRI using an atlas-aided fuzzy C-means method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shandong; Weinstein, Susan P.; Conant, Emily F.; Kontos, Despina, E-mail: despina.kontos@uphs.upenn.edu [Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2013-12-15

    Purpose: Breast magnetic resonance imaging (MRI) plays an important role in the clinical management of breast cancer. Studies suggest that the relative amount of fibroglandular (i.e., dense) tissue in the breast as quantified in MR images can be predictive of the risk for developing breast cancer, especially for high-risk women. Automated segmentation of the fibroglandular tissue and volumetric density estimation in breast MRI could therefore be useful for breast cancer risk assessment. Methods: In this work the authors develop and validate a fully automated segmentation algorithm, namely, an atlas-aided fuzzy C-means (FCM-Atlas) method, to estimate the volumetric amount of fibroglandular tissue in breast MRI. The FCM-Atlas is a 2D segmentation method working on a slice-by-slice basis. FCM clustering is first applied to the intensity space of each 2D MR slice to produce an initial voxelwise likelihood map of fibroglandular tissue. Then a prior learned fibroglandular tissue likelihood atlas is incorporated to refine the initial FCM likelihood map to achieve enhanced segmentation, from which the absolute volume of the fibroglandular tissue (|FGT|) and the relative amount (i.e., percentage) of the |FGT| relative to the whole breast volume (FGT%) are computed. The authors' method is evaluated by a representative dataset of 60 3D bilateral breast MRI scans (120 breasts) that span the full breast density range of the American College of Radiology Breast Imaging Reporting and Data System. The automated segmentation is compared to manual segmentation obtained by two experienced breast imaging radiologists. Segmentation performance is assessed by linear regression, Pearson's correlation coefficients, Student's pairedt-test, and Dice's similarity coefficients (DSC). Results: The inter-reader correlation is 0.97 for FGT% and 0.95 for |FGT|. When compared to the average of the two readers’ manual segmentation, the proposed FCM-Atlas method achieves a