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Sample records for 3-tesla high resolution

  1. Vascular compression in glossopharyngeal neuralgia: demonstration by high-resolution MRI at 3 tesla

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    Fischbach, F.; Ricke, J.; Bruhn, H. [Department of Radiology, Charite, Campus Virchow Klinikum, Humboldt-University, Augustenburger Platz 1, 13352, Berlin (Germany); Lehmann, T.N. [Department of Neurosurgery, Charite, Campus Virchow Klinikum, Humboldt-University, Augustenberger Platz 1, 13353, Berlin (Germany)

    2003-11-01

    We report a case of glossopharyngeal neuralgia with vascular compression. High-resolution MRI at 3 tesla demonstrated the posterior inferior cerebellar artery to be closely related to the rootlets of the left glossopharyngeal nerve in a patient who suffered attacks of burning sensation in the left side of the throat. The MRI findings were confirmed at curative surgery. (orig.)

  2. [Examination of upper abdominal region in high spatial resolution diffusion-weighted imaging using 3-Tesla MRI].

    Science.gov (United States)

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

    2009-03-20

    The advantage of the higher signal-to-noise ratio (SNR) of 3-Tesla magnetic resonance imaging (3-Tesla) has the possibility of contributing to the improvement of high spatial resolution without causing image deterioration. In this study, we compared SNR and the apparent diffusion coefficient (ADC) value with 3-Tesla as the condition in the diffusion-weighted image (DWI) parameter of the 1.5-Tesla magnetic resonance imaging (1.5-Tesla) and we examined the high spatial resolution images in the imaging method [respiratory-triggering (RT) method and breath free (BF) method] and artifact (motion and zebra) in the upper abdominal region of DWI at 3-Tesla. We have optimized scan parameters based on phantom and in vivo study. As a result, 3-Tesla was able to obtain about 1.5 times SNR in comparison with the 1.5-Tesla, ADC value had few differences. Moreover, the RT method was effective in correcting the influence of respiratory movement in comparison with the BF method, and image improvement by the effective acquisition of SNR and reduction of the artifact were provided. Thus, DWI of upper abdominal region was a useful sequence for the high spatial resolution in 3-Tesla.

  3. High-resolution motion compensated MRA in patients with congenital heart disease using extracellular contrast agent at 3 Tesla

    Directory of Open Access Journals (Sweden)

    Dabir Darius

    2012-10-01

    Full Text Available Abstract Background Using first-pass MRA (FP-MRA spatial resolution is limited by breath-hold duration. In addition, image quality may be hampered by respiratory and cardiac motion artefacts. In order to overcome these limitations an ECG- and navigator-gated high-resolution-MRA sequence (HR-MRA with slow infusion of extracellular contrast agent was implemented at 3 Tesla for the assessment of congenital heart disease and compared to standard first-pass-MRA (FP-MRA. Methods 34 patients (median age: 13 years with congenital heart disease (CHD were prospectively examined on a 3 Tesla system. The CMR-protocol comprised functional imaging, FP- and HR-MRA, and viability imaging. After the acquisition of the FP-MRA sequence using a single dose of extracellular contrast agent the motion compensated HR-MRA sequence with isotropic resolution was acquired while injecting the second single dose, utilizing the timeframe before viability imaging. Qualitative scores for image quality (two independent reviewers as well as quantitative measurements of vessel sharpness and relative contrast were compared using the Wilcoxon signed-rank test. Quantitative measurements of vessel diameters were compared using the Bland-Altman test. Results The mean image quality score revealed significantly better image quality of the HR-MRA sequence compared to the FP-MRA sequence in all vessels of interest (ascending aorta (AA, left pulmonary artery (LPA, left superior pulmonary vein (LSPV, coronary sinus (CS, and coronary ostia (CO; all p  Conclusions An ECG- and navigator-gated HR-MRA-protocol with infusion of extracellular contrast agent at 3 Tesla is feasible. HR-MRA delivers significantly better image quality and vessel sharpness compared to FP-MRA. It may be integrated into a standard CMR-protocol for patients with CHD without the need for additional contrast agent injection and without any additional examination time.

  4. High resolution neurography of the brachial plexus by 3 Tesla magnetic resonance imaging.

    Science.gov (United States)

    Cejas, C; Rollán, C; Michelin, G; Nogués, M

    2016-01-01

    The study of the structures that make up the brachial plexus has benefited particularly from the high resolution images provided by 3T magnetic resonance scanners. The brachial plexus can have mononeuropathies or polyneuropathies. The mononeuropathies include traumatic injuries and trapping, such as occurs in thoracic outlet syndrome due to cervical ribs, prominent transverse apophyses, or tumors. The polyneuropathies include inflammatory processes, in particular chronic inflammatory demyelinating polyneuropathy, Parsonage-Turner syndrome, granulomatous diseases, and radiation neuropathy. Vascular processes affecting the brachial plexus include diabetic polyneuropathy and the vasculitides. This article reviews the anatomy of the brachial plexus and describes the technique for magnetic resonance neurography and the most common pathologic conditions that can affect the brachial plexus. Copyright © 2016 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  5. High-resolution cine MRI with TGRAPPA for fast assessment of left ventricular function at 3 Tesla

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    Theisen, Daniel, E-mail: daniel.theisen@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Munich Heart Alliance, Munich (Germany); Sandner, Torleif A., E-mail: torleif.sandner@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Bamberg, Fabian, E-mail: fabian.bamberg@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Munich Heart Alliance, Munich (Germany); Bauner, Kerstin U., E-mail: kerstin.bauner@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Schwab, Felix, E-mail: felix.schwab@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Schwarz, Florian, E-mail: florian.schwarz@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Arnoldi, Elisabeth, E-mail: elisabeth.arnoldi@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Reiser, Maximilian F., E-mail: maximilian.reiser@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Munich Heart Alliance, Munich (Germany); Wintersperger, Bernd J., E-mail: bernd.wintersperger@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Department of Medical Imaging, University of Toronto, Toronto, Ontario (Canada)

    2013-05-15

    Purpose: To implement and evaluate the accuracy of multislice dual-breath hold cine MR for analysis of global systolic and diastolic left ventricular function at 3 T. Materials and methods: 25 patients referred to cardiac MR underwent cine imaging at 3 T (MAGNETOM Verio) using prospective triggered SSFP (TR 3.1 ms; TE 1.4 ms; FA 60°). Analysis of LV function was performed using a standard non-accelerated single-slice approach (STD) with multiple breath-holds and an accelerated multi-slice technique (TGRAPPA; R = 4) encompassing the ventricles with 5 slices/breath-hold. Parameters of spatial and temporal resolution were kept identical (pixel: 1.9 × 2.5 mm{sup 2}; temporal resolution: 47 ms). Data of both acquisition techniques were analyzed by two readers using semiautomatic algorithms (syngoARGUS) with respect to EDV, ESV, EF, myocardial mass (MM), peak filling rate (PFR) and peak ejection rate (PER) including assessment of interobserver agreement. Results: Volumetric results of the TGRAPPA approach did not show significant differences to the STD approach for left ventricular ejection fraction (62.3 ± 10.6 vs. 61.0 ± 8.4, P = 0.2), end-diastolic volume (135.8 ± 47.5 vs. 130.8 ± 46.4, P = 0.07), endsystolic volume (53.0 ± 29.7 vs. 53.1 ± 32.7, P = 0.99) and myocardial mass (114.2 ± 32.5 vs. 114.6 ± 30.6, P = 0.9). Moreover, a comparison of peak ejection rate (601.3 ± 190.2 vs. 590.8 ± 218.2, P = 0.8) and peak filling rate (535.1 ± 191.2 vs. 535.4 ± 210.7, P = 0.99) did not reveal significant differences between the two groups. Limits in interobserver agreement were low for all systolic and diastolic parameters in both groups (P ≥ 0.05). Total acquisition time for STD was 273 ± 124 s and 34 ± 5 s for TGRAPPA (P ≤ 0.001). Evaluation time for standard and multislice approach was equal (10.8 ± 1.4 vs. 9.8 ± 2.1 min; P = 0.08)

  6. Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

    Science.gov (United States)

    Chang, Hing-Chiu; Sundman, Mark; Petit, Laurent; Guhaniyogi, Shayan; Chu, Mei-Lan; Petty, Christopher; Song, Allen W; Chen, Nan-kuei

    2015-09-01

    The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in data at a submillimeter isotropic resolution. To our knowledge, in vivo human brain DTI at a submillimeter isotropic resolution has not been routinely achieved yet because of the difficulty in simultaneously achieving high resolution and high signal-to-noise ratio (SNR) in DTI scans. Here we report a 3D multi-slab interleaved EPI acquisition integrated with multiplexed sensitivity encoded (MUSE) reconstruction, to achieve high-quality, high-SNR and submillimeter isotropic resolution (0.85×0.85×0.85mm(3)) in vivo human brain DTI on a 3Tesla clinical MRI scanner. In agreement with the previously reported post-mortem human brain DTI study, our in vivo data show that the structural connectivity networks of human brains can be mapped more accurately and completely with high-resolution DTI as compared with conventional DTI (e.g., 2×2×2mm(3)).

  7. Correlation of structural abnormalities of the wrist and metacarpophalangeal joints evaluated by high-resolution peripheral quantitative computed tomography, 3 Tesla magnetic resonance imaging and conventional radiographs in rheumatoid arthritis.

    Science.gov (United States)

    Lee, Chan Hee; Srikhum, Waraporn; Burghardt, Andrew J; Virayavanich, Warapat; Imboden, John B; Link, Thomas M; Li, Xiaojuan

    2015-07-01

    In rheumatoid arthritis (RA) hands, we applied high-resolution peripheral quantitative computed tomography (HR-pQCT) and 3 Tesla (3 T) magnetic resonance imaging (MRI), which are new methods for erosion detection and bone marrow edema (BME) quantification. We compared the erosion measurements between these techniques with conventional radiographs (CR) in order to examine their significance for evaluating structural abnormalities. In 16 RA patients, HR-pQCT of metacarpophalangeal and wrist joints, 3 T MRI of wrist joints, as well as CR in both hands and feet were performed. Ten patients had 1-year follow-up CR. CRs were graded according to the modified Sharp score (MSS). Bone erosions were evaluated in HR-pQCT and MRI. BME pattern was quantified from MRI for volume, signal change and total burden. The erosion detection sensitivity of MRI was 85.7% and CR was 60.9% when HR-pQCT was considered as a reference method. The smallest dimensions of erosion detected by HR-pQCT, MRI and CR were 0.09, 0.14 and 0.66 cm, respectively. Baseline total MSS was correlated with HR-pQCT erosion measures, MRI erosion measures and MRI BME volume (P < 0.05). The mean difference between baseline and 1-year follow-up MSS (delta MSS) was 1.2. A trend was observed toward a correlation between delta MSS and MRI BME volume and burden. This study demonstrates that HR-pQCT detects more and smaller bone erosions compared to MRI and CR. In addition, 3 T MRI can provide quantitative measurement of BME. Combination of HR-pQCT and MRI modalities may provide powerful tools to evaluate joint inflammation and bone damage in RA. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

  8. Knee implant imaging at 3 Tesla using high-bandwidth radiofrequency pulses.

    Science.gov (United States)

    Bachschmidt, Theresa J; Sutter, Reto; Jakob, Peter M; Pfirrmann, Christian W A; Nittka, Mathias

    2015-06-01

    To investigate the impact of high-bandwidth radiofrequency (RF) pulses used in turbo spin echo (TSE) sequences or combined with slice encoding for metal artifact correction (SEMAC) on artifact reduction at 3 Tesla in the knee in the presence of metal. Local transmit/receive coils feature increased maximum B1 amplitude, reduced SAR exposition and thus enable the application of high-bandwidth RF pulses. Susceptibility-induced through-plane distortion scales inversely with the RF bandwidth and the view angle, hence blurring, increases for higher RF bandwidths, when SEMAC is used. These effects were assessed for a phantom containing a total knee arthroplasty. TSE and SEMAC sequences with conventional and high RF bandwidths and different contrasts were tested on eight patients with different types of implants. To realize scan times of 7 to 9 min, SEMAC was always applied with eight slice-encoding steps and distortion was rated by two radiologists. A local transmit/receive knee coil enables the use of an RF bandwidth of 4 kHz compared with 850 Hz in conventional sequences. Phantom scans confirm the relation of RF bandwidth and through-plane distortion, which can be reduced up to 79%, and demonstrate the increased blurring for high-bandwidth RF pulses. In average, artifacts in this RF mode are rated hardly visible for patients with joint arthroplasties, when eight SEMAC slice-encoding steps are applied, and for patients with titanium fixtures, when TSE is used. The application of high-bandwidth RF pulses by local transmit coils substantially reduces through-plane distortion artifacts at 3 Tesla. © 2014 Wiley Periodicals, Inc.

  9. Functionality of veterinary identification microchips following low- (0.5 tesla) and high-field (3 tesla) magnetic resonance imaging.

    Science.gov (United States)

    Piesnack, Susann; Frame, Mairi E; Oechtering, Gerhard; Ludewig, Eberhard

    2013-01-01

    The ability to read patient identification microchips relies on the use of radiofrequency pulses. Since radiofrequency pulses also form an integral part of the magnetic resonance imaging (MRI) process, the possibility of loss of microchip function during MRI scanning is of concern. Previous clinical trials have shown microchip function to be unaffected by MR imaging using a field strength of 1 Tesla and 1.5. As veterinary MRI scanners range widely in field strength, this study was devised to determine whether exposure to lower or higher field strengths than 1 Tesla would affect the function of different types of microchip. In a phantom study, a total of 300 International Standards Organisation (ISO)-approved microchips (100 each of three different types: ISO FDX-B 1.4 × 9 mm, ISO FDX-B 2.12 × 12 mm, ISO HDX 3.8 × 23 mm) were tested in a low field (0.5) and a high field scanner (3.0 Tesla). A total of 50 microchips of each type were tested in each scanner. The phantom was composed of a fluid-filled freezer pack onto which a plastic pillow and a cardboard strip with affixed microchips were positioned. Following an MRI scan protocol simulating a head study, all of the microchips were accurately readable. Neither 0.5 nor 3 Tesla imaging affected microchip function in this study. © 2013 Veterinary Radiology & Ultrasound.

  10. Endometrium evaluation with high-field (3-Tesla) magnetic resonance imaging in patients submitted to uterine leiomyoma embolization

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    Jacobs, Monica Amadio Piazza [Post-graduation Program in Abdominal Imaging, Hospital Israelita Albert Einstein, São Paulo, SP (Brazil); Nasser, Felipe [Intervention Radiology Department, Hospital Israelita Albert Einstein, São Paulo, SP (Brazil); Zlotnik, Eduardo; Messina, Marcos de Lorenzo [Gynecology and Obstetrics Department, Hospital Israelita Albert Einstein, São Paulo, SP (Brazil); Baroni, Ronaldo Hueb [Magnetic Resonance Unit, Imaging Department, Hospital Israelita Albert Einstein, São Paulo, SP (Brazil)

    2013-07-01

    To evaluate the endometrial alterations related to embolization of uterine arteries for the treatment of symptomatic uterine leiomyomatosis (pelvic pain and/or uterine bleeding) by means of high-field (3-Tesla) magnetic resonance. This is a longitudinal and prospective study that included 94 patients with a clinical and imaging diagnosis of symptomatic uterine leiomyomatosis, all of them treated by embolization of the uterine arteries. The patients were submitted to evaluations by high-field magnetic resonance of the pelvis before and 6 months after the procedure. Specific evaluations were made of the endometrium on the T2-weighted sequences, and on the T1-weighted sequences before and after the intravenous dynamic infusion of the paramagnetic contrast. In face of these measures, statistical analyses were performed using Student's t test for comparison of the results obtained before and after the procedure. An average increase of 20.9% was noted in the endometrial signal on T2-weighted images obtained after the uterine artery embolization procedure when compared to the pre-procedure evaluation (p=0.0004). In the images obtained with the intravenous infusion of paramagnetic contrast, an average increase of 18.7% was noted in the post-embolization intensity of the endometrial signal, compared to the pre-embolization measure (p<0.035). After embolization of the uterine arteries, there was a significant increase of the endometrial signal on the T2-weighted images and on the post-contrast images, inferring possible edema and increased endometrial flow. Future studies are needed to assess the clinical impact of these findings.

  11. Evaluation of preoperative high magnetic field motor functional MRI (3 Tesla) in glioma patients by navigated electrocortical stimulation and postoperative outcome

    National Research Council Canada - National Science Library

    Roessler, K; Donat, M; Lanzenberger, R; Novak, K; Geissler, A; Gartus, A; Tahamtan, A R; Milakara, D; Czech, T; Barth, M; Knosp, E; Beisteiner, R

    2005-01-01

    The validity of 3 Tesla motor functional magnetic resonance imaging (fMRI) in patients with gliomas involving the primary motor cortex was investigated by intraoperative navigated motor cortex stimulation (MCS...

  12. Resection and Resolution of Bone Marrow Lesions Associated with an Improvement of Pain after Total Knee Replacement: A Novel Case Study Using a 3-Tesla Metal Artefact Reduction MRI Sequence.

    Science.gov (United States)

    Kurien, Thomas; Kerslake, Robert; Haywood, Brett; Pearson, Richard G; Scammell, Brigitte E

    2016-01-01

    We present our case report using a novel metal artefact reduction magnetic resonance imaging (MRI) sequence to observe resolution of subchondral bone marrow lesions (BMLs), which are strongly associated with pain, in a patient after total knee replacement surgery. Large BMLs were seen preoperatively on the 3-Tesla MRI scans in a patient with severe end stage OA awaiting total knee replacement surgery. Twelve months after surgery, using a novel metal artefact reduction MRI sequence, we were able to visualize the bone-prosthesis interface and found complete resection and resolution of these BMLs. This is the first reported study in the UK to use this metal artefact reduction MRI sequence at 3-Tesla showing that resection and resolution of BMLs in this patient were associated with an improvement of pain and function after total knee replacement surgery. In this case it was associated with a clinically significant improvement of pain and function after surgery. Failure to eradicate these lesions may be a cause of persistent postoperative pain that is seen in up to 20% of patients following TKR surgery.

  13. Impact of high resolution 3 tesla MR neurography (MRN) on diagnostic thinking and therapeutic patient management

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    Chhabra, Avneesh [Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Belzberg, Allan J. [Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, MD (United States); Rosson, Gedge D.; Shores, Jaimie T.; Deune, Gene [Johns Hopkins University School of Medicine, Department of Plastic Surgery, Baltimore, MD (United States); Thawait, Gaurav K.; Chalian, M.; Farahani, Sahar J.; Thawait, Shrey K. [Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Hashemi, Shar [Dellon Institute, Towson, MD (United States); Subhawong, Ty K. [University of Miami Health System, Department of Radiology, Miami, FL (United States); Carrino, John A. [Weill Cornell Medical College, Hospital for Special Surgery, Department of Radiology and Imaging, New York, NY (United States)

    2016-05-15

    To evaluate the impact of magnetic resonance neurography (MRN) on diagnostic thinking and therapeutic choices in patients with suspected peripheral neuropathy. IRB approval was obtained for this HIPAA-compliant study. Questionnaires were administered to six surgeons regarding the diagnosis and treatment in 85 patients suspected of having peripheral neuropathy, before (pretest) and after (posttest) MRN. Multiple outcome measures related to diagnostic confidence and surgical decision-making were assessed. The final cohort included 81 patients (30 men and 51 women, age 47 ± 17 years). The following changes were observed from pretest to posttest questionnaires: 23 % in nerve involvement (P < 0.05), 48 % in degree of confidence of nerve involvement (P < 0.01), 27 % in grade of injury (P < 0.05), 33 % in differential diagnosis (P < 0.05), 63 % in degree of confidence in need for surgery (P < 0.001), 41 % in timing of surgery (P < 0.01), 30 % in approach to surgery (P < 0.05), 58 % in degree of confidence in approach to surgery (P < 0.001), 30 % in estimated length of surgery (P < 0.05) and 27 % in length of incision (P < 0.05). The dichotomous decision regarding surgical or nonsurgical treatment changed from pro to con in 17 %. MRN results significantly influenced the diagnostic thinking and therapeutic recommendations of peripheral nerve surgeons. circle In patients with peripheral neuropathy, MRN significantly impacts diagnostic thinking. (orig.)

  14. Evaluation of preoperative high magnetic field motor functional MRI (3 Tesla) in glioma patients by navigated electrocortical stimulation and postoperative outcome.

    Science.gov (United States)

    Roessler, K; Donat, M; Lanzenberger, R; Novak, K; Geissler, A; Gartus, A; Tahamtan, A R; Milakara, D; Czech, T; Barth, M; Knosp, E; Beisteiner, R

    2005-08-01

    The validity of 3 Tesla motor functional magnetic resonance imaging (fMRI) in patients with gliomas involving the primary motor cortex was investigated by intraoperative navigated motor cortex stimulation (MCS). Twenty two patients (10 males, 12 females, mean age 39 years, range 10-65 years) underwent preoperative fMRI studies, performing motor tasks including hand, foot, and mouth movements. A recently developed high field clinical fMRI technique was used to generate pre-surgical maps of functional high risk areas defining a motor focus. Motor foci were tested for validity by intraoperative motor cortex stimulation (MCS) employing image fusion and neuronavigation. Clinical outcome was assessed using the Modified Rankin Scale. FMRI motor foci were successfully detected in all patients preoperatively. In 17 of 22 patients (77.3%), a successful stimulation of the primary motor cortex was possible. All 17 correlated patients showed 100% agreement on MCS and fMRI motor focus within 10 mm. Technical problems during stimulation occurred in three patients (13.6%), no motor response was elicited in two (9.1%), and MCS induced seizures occurred in three (13.6%). Combined fMRI and MCS mapping results allowed large resections in 20 patients (91%) (gross total in nine (41%), subtotal in 11 (50%)) and biopsy in two patients (9%). Pathology revealed seven low grade and 15 high grade gliomas. Mild to moderate transient neurological deterioration occurred in six patients, and a severe hemiparesis in one. All patients recovered within 3 months (31.8% transient, 0% permanent morbidity). The validation of clinically optimised high magnetic field motor fMRI confirms high reliability as a preoperative and intraoperative adjunct in glioma patients selected for surgery within or adjacent to the motor cortex.

  15. Using 3 Tesla magnetic resonance imaging in the pre-operative evaluation of tongue carcinoma.

    Science.gov (United States)

    Moreno, K F; Cornelius, R S; Lucas, F V; Meinzen-Derr, J; Patil, Y J

    2017-09-01

    This study aimed to evaluate the role of 3 Tesla magnetic resonance imaging in predicting tongue tumour thickness via direct and reconstructed measures, and their correlations with corresponding histological measures, nodal metastasis and extracapsular spread. A prospective study was conducted of 25 patients with histologically proven squamous cell carcinoma of the tongue and pre-operative 3 Tesla magnetic resonance imaging from 2009 to 2012. Correlations between 3 Tesla magnetic resonance imaging and histological measures of tongue tumour thickness were assessed using the Pearson correlation coefficient: r values were 0.84 (p Tesla magnetic resonance imaging had 83 per cent sensitivity, 82 per cent specificity, 82 per cent accuracy and a 90 per cent negative predictive value for detecting cervical lymph node metastasis. In this cohort, 3 Tesla magnetic resonance imaging measures of tumour thickness correlated highly with the corresponding histological measures. Further, 3 Tesla magnetic resonance imaging was an effective method of detecting malignant adenopathy with extracapsular spread.

  16. Intraindividual comparison of image quality in MR urography at 1.5 and 3 Tesla in an animal model

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    Regier, M.; Adam, G.; Kemper, J. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany); Nolte-Ernsting, C. [Klinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany)

    2008-10-15

    Purpose: experimental evaluation of image quality of the upper urinary tract in MR urography (MRU) at 1.5 and 3 Tesla in a porcine model. Materials and methods: in this study four healthy domestic pigs, weighing between 71 and 80 kg (mean 73.6 kg), were examined with a standard T 1w 3D-GRE and a high-resolution (HR) T 1w 3D-GRE sequence at 1.5 and 3 Tesla. Additionally, at 3 Tesla both sequences were performed with parallel imaging (SENSE factor 2). The MR urographic scans were performed after intravenous injection of gadolinium-DTPA (0.1 mmol/kg body weight (bw)) and low-dose furosemide (0.1 mg/kg bw). Image evaluation was performed by two independent radiologists blinded to sequence parameters and field strength. Image analysis included grading of image quality of the segmented collecting system based on a five-point grading scale regarding anatomical depiction and artifacts observed (1: the majority of the segment (> 50%) was not depicted or was obscured by major artifacts; 5: the segment was visualized without artifacts and had sharply defined borders). Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were determined. Statistical analysis included {kappa}-statistics, Wilcoxon and paired student t-test. Results: the mean scores for MR urographies at 1.5 Tesla were 2.83 for the 3D-GRE and 3.48 for the HR 3D-GRE sequence. Significantly higher values were determined using the corresponding sequences at 3 Tesla, averaging 3.19 for the 3D-GRE (p = 0.047) and 3.92 for the HR 3D-GRE (p = 0.023) sequence. Delineation of the pelvicaliceal system was rated significantly higher at 3 Tesla compared to 1.5 Tesla (3D-GRE: p = 0.015; HR 3D-GRE: p = 0.006). At 3 Tesla the mean SNR and CNR were significantly higher (p < 0.05). A {kappa} of 0.67 indicated good interobserver agreement. (orig.)

  17. Intraindividual comparison of image quality in MR urography at 1.5 and 3 tesla in an animal model.

    Science.gov (United States)

    Regier, M; Nolte-Ernsting, C; Adam, G; Kemper, J

    2008-10-01

    Experimental evaluation of image quality of the upper urinary tract in MR urography (MRU) at 1.5 and 3 Tesla in a porcine model. In this study four healthy domestic pigs, weighing between 71 and 80 kg (mean 73.6 kg), were examined with a standard T1w 3D-GRE and a high-resolution (HR) T1w 3D-GRE sequence at 1.5 and 3 Tesla. Additionally, at 3 Tesla both sequences were performed with parallel imaging (SENSE factor 2). The MR urographic scans were performed after intravenous injection of gadolinium-DTPA (0.1 mmol/kg body weight (bw)) and low-dose furosemide (0.1 mg/kg bw). Image evaluation was performed by two independent radiologists blinded to sequence parameters and field strength. Image analysis included grading of image quality of the segmented collecting system based on a five-point grading scale regarding anatomical depiction and artifacts observed (1: the majority of the segment (>50%) was not depicted or was obscured by major artifacts; 5: the segment was visualized without artifacts and had sharply defined borders). Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were determined. Statistical analysis included kappa-statistics, Wilcoxon and paired student t-test. The mean scores for MR urographies at 1.5 Tesla were 2.83 for the 3D-GRE and 3.48 for the HR3D-GRE sequence. Significantly higher values were determined using the corresponding sequences at 3 Tesla, averaging 3.19 for the 3D-GRE (p = 0.047) and 3.92 for the HR3D-GRE (p = 0,023) sequence. Delineation of the pelvicaliceal system was rated significantly higher at 3 Tesla compared to 1.5 Tesla (3D-GRE: p = 0.015; HR3D-GRE: p = 0.006). At 3 Tesla the mean SNR and CNR were significantly higher (p Tesla allowed for significantly higher image quality and SNR compared to 1.5 Tesla, particularly for the visualization of the pelvicaliceal system.

  18. Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla

    DEFF Research Database (Denmark)

    Foged, Mette Thrane; Lindberg, Ulrich; Vakamudi, Kishore

    2017-01-01

    with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual...... ballistocardiographic artifacts resulted in 58% of EEG data being rated as poor quality. CONCLUSION: This study demonstrates that high-density EEG can be safely implemented in conjunction with high-speed fMRI and that high-speed fMRI does not adversely affect EEG data quality. However, the deterioration of the EEG...... quality due to residual ballistocardiographic artifacts remains a significant constraint for routine clinical applications of concurrent EEG-fMRI....

  19. Evaluation of aqueductal patency in patients with hydrocephalus: three-dimensional high-sampling-efficiency technique (SPACE) versus two-dimensional turbo spin echo at 3 Tesla.

    Science.gov (United States)

    Ucar, Murat; Guryildirim, Melike; Tokgoz, Nil; Kilic, Koray; Borcek, Alp; Oner, Yusuf; Akkan, Koray; Tali, Turgut

    2014-01-01

    To compare the accuracy of diagnosing aqueductal patency and image quality between high spatial resolution three-dimensional (3D) high-sampling-efficiency technique (sampling perfection with application optimized contrast using different flip angle evolutions [SPACE]) and T2-weighted (T2W) two-dimensional (2D) turbo spin echo (TSE) at 3-T in patients with hydrocephalus. This retrospective study included 99 patients diagnosed with hydrocephalus. T2W 3D-SPACE was added to the routine sequences which consisted of T2W 2D-TSE, 3D-constructive interference steady state (CISS), and cine phase-contrast MRI (PC-MRI). Two radiologists evaluated independently the patency of cerebral aqueduct and image quality on the T2W 2D-TSE and T2W 3D-SPACE. PC-MRI and 3D-CISS were used as the reference for aqueductal patency and image quality, respectively. Inter-observer agreement was calculated using kappa statistics. The evaluation of the aqueductal patency by T2W 3D-SPACE and T2W 2D-TSE were in agreement with PC-MRI in 100% (99/99; sensitivity, 100% [83/83]; specificity, 100% [16/16]) and 83.8% (83/99; sensitivity, 100% [67/83]; specificity, 100% [16/16]), respectively (p dimensional-SPACE is superior to 2D-TSE for the evaluation of aqueductal patency in hydrocephalus. T2W 3D-SPACE may hold promise as a highly accurate alternative treatment to PC-MRI for the physiological and morphological evaluation of aqueductal patency.

  20. Qualitative Evaluation of a High-Resolution 3D Multi-Sequence Intracranial Vessel Wall Protocol at 3 Tesla MRI

    NARCIS (Netherlands)

    Dieleman, Nikki; Yang, Wenjie; van der Kolk, Anja G; Abrigo, Jill; Lee, Ka Lok; Chu, Winnie Chiu Wing; Zwanenburg, Jaco J M; Siero, Jeroen C. W.; Wong, Ka Sing; Hendrikse, Jeroen; Chen, Fiona Xiang Yan

    2016-01-01

    BACKGROUND AND PURPOSE: Intracranial vessel wall imaging using MRI has great potential as a clinical method for assessing intracranial atherosclerosis. The purpose of the current study was to compare three 3T MRI vessel wall sequences with different contrast weightings (T1w, PD, T2w) and dedicated s

  1. Evaluation of aqueductal patency in patients with hydrocephalus: Three-dimensional high-sampling efficiency technique(SPACE) versus two-dimensional turbo spin echo at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Ucar, Murat; Guryildirim, Melike; Tokgoz, Nil; Kilic, Koray; Borcek, Alp; Oner, Yusuf; Akkan, Koray; Tali, Turgut [School of Medicine, Gazi University, Ankara (Turkey)

    2014-12-15

    To compare the accuracy of diagnosing aqueductal patency and image quality between high spatial resolution three-dimensional (3D) high-sampling-efficiency technique (sampling perfection with application optimized contrast using different flip angle evolutions [SPACE]) and T2-weighted (T2W) two-dimensional (2D) turbo spin echo (TSE) at 3-T in patients with hydrocephalus. This retrospective study included 99 patients diagnosed with hydrocephalus. T2W 3D-SPACE was added to the routine sequences which consisted of T2W 2D-TSE, 3D-constructive interference steady state (CISS), and cine phase-contrast MRI (PC-MRI). Two radiologists evaluated independently the patency of cerebral aqueduct and image quality on the T2W 2D-TSE and T2W 3D-SPACE. PC-MRI and 3D-CISS were used as the reference for aqueductal patency and image quality, respectively. Inter-observer agreement was calculated using kappa statistics. The evaluation of the aqueductal patency by T2W 3D-SPACE and T2W 2D-TSE were in agreement with PC-MRI in 100% (99/99; sensitivity, 100% [83/83]; specificity, 100% [16/16]) and 83.8% (83/99; sensitivity, 100% [67/83]; specificity, 100% [16/16]), respectively (p < 0.001). No significant difference in image quality between T2W 2D-TSE and T2W 3D-SPACE (p = 0.056) occurred. The kappa values for inter-observer agreement were 0.714 for T2W 2D-TSE and 0.899 for T2W 3D-SPACE. Three-dimensional-SPACE is superior to 2D-TSE for the evaluation of aqueductal patency in hydrocephalus. T2W 3D-SPACE may hold promise as a highly accurate alternative treatment to PC-MRI for the physiological and morphological evaluation of aqueductal patency.

  2. Dobutamine stress cardiovascular magnetic resonance at 3 Tesla

    Directory of Open Access Journals (Sweden)

    Klein C

    2008-10-01

    Full Text Available Abstract Purpose The assessment of inducible wall motion abnormalities during high-dose dobutamine-stress cardiovascular magnetic resonance (DCMR is well established for the identification of myocardial ischemia at 1.5 Tesla. Its feasibility at higher field strengths has not been reported. The present study was performed to prospectively determine the feasibility and diagnostic accuracy of DCMR at 3 Tesla for depicting hemodynamically significant coronary artery stenosis (≥ 50% diameter stenosis in patients with suspected or known coronary artery disease (CAD. Materials and methods Thirty consecutive patients (6 women (66 ± 9.3 years were scheduled for DCMR between January and May 2007 for detection of coronary artery disease. Patients were examined with a Philips Achieva 3 Tesla system (Philips Healthcare, Best, The Netherlands, using a spoiled gradient echo cine sequence. Technical parameters were: spatial resolution 2 × 2 × 8 mm3, 30 heart phases, spoiled gradient echo TR/TE: 4.5/2.6 msec, flip angle 15°. Images were acquired at rest and stress in accordance with a standardized high-dose dobutamine-atropine protocol during short breath-holds in three short and three long-axis views. Dobutamine was administered using a standard protocol (10 μg increments every 3 minutes up to 40 μg dobutamine/kg body weight/minute plus atropine if required to reach target heart rate. The study protocol included administration of 0.1 mmol/kg/body weight Gd-DTPA before the cine images at rest were acquired to improve the image quality. The examination was terminated if new or worsening wall-motion abnormalities or chest pain occurred or when > 85% of age-predicted maximum heart rate was reached. Myocardial ischemia was defined as new onset of wall-motion abnormality in at least one segment. In addition, late gadolinium enhancement (LGE was performed. Images were evaluated by two blinded readers. Diagnostic accuracy was determined with coronary

  3. Meralgia paresthetica: 3-Tesla magnetic resonance neurography.

    Science.gov (United States)

    Chhabra, Avneesh; Del Grande, Filippo; Soldatos, Theodoros; Chalian, Majid; Belzberg, Allan J; Williams, Eric H; Jalali, Farahani S; Thawait, Gaurav K; Eng, John; Carrino, John A

    2013-06-01

    To assess the diagnostic accuracy and observer performance of 3-Tesla magnetic resonance neurography (MRN) in the evaluation of meralgia paresthetica (MP). Two independent readers were blinded to the clinical diagnosis and evaluated the MRN studies of the pelvis of 11 patients with MP and 28 control participants. In each study, the lateral femoral cutaneous nerves were assessed for signal alteration and/or neuroma formation, indicating lateral femoral cutaneous neuropathy, at various levels along their course. Intra- and inter-observer reliability was evaluated. Both readers exhibited substantial intraobserver agreement in detecting signal alterations and neuroma formation of the lateral femoral cutaneous nerve (LFCN). The readers demonstrated moderate interobserver agreement in detecting signal alteration of the LFCN and poor interobserver agreement in diagnosing neuroma formation. Sensitivity, specificity, positive predictive value, and negative predictive value of LFCN neuropathy diagnosis were ≥ 71 % and ≥ 94 % for both readers respectively. The diagnostic test accuracy was ≥ 90 % for both readers. 3-Tesla MRN provides reliable and accurate diagnostic evaluation of meralgia paresthetica.

  4. Evaluation of Aqueductal Patency in Patients with Hydrocephalus: Three-Dimensional High-Sampling-Efficiency Technique (SPACE) versus Two-Dimensional Turbo Spin Echo at 3 Tesla

    National Research Council Canada - National Science Library

    Ucar, Murat; Guryildirim, Melike; Tokgoz, Nil; Kilic, Koray; Borcek, Alp; Oner, Yusuf; Akkan, Koray; Tali, Turgut

    2014-01-01

    ...) high-sampling-efficiency technique (sampling perfection with application optimized contrast using different flip angle evolutions [SPACE]) and T2-weighted (T2W) two-dimensional (2D) turbo spin echo (TSE...

  5. Volumetric ablation of uterine fibroids using Sonalleve high-intensity focused ultrasound in a 3 Tesla scanner--first clinical assessment.

    Science.gov (United States)

    Dorenberg, Eric J; Courivaud, Frédéric; Ring, Eva; Hald, Kirsten; Jakobsen, Jarl Å; Fosse, Erik; Hol, Per Kristian

    2013-04-01

    The purpose of this study was to evaluate the feasibility and safety of the Sonalleve high-intensity focused ultrasound (HIFU; Philips Healthcare, Vantaa, Finland) system in ablating uterine fibroids in a 3T magnet. Seven women were included in this study. Treatment was performed according to the manufacturer's recommendation. Technical data describing the HIFU procedures were collected. On MR images at baseline, immediately and 30 days after ablation, we evaluated the volumes of the uterus, the dominant fibroid and the ablation zone. The Uterine Fibroid Symptom and Quality of Life (UFS-QOL) questionnaire was used to assess potential clinical response. The procedure was technically feasible in all patients. The median number of sonications performed during each procedure was 20 (range 2-27) per patient, the maximum temperature in all sonication cells was about 68°C. The median procedure time was 156 minutes (range 95-164). The non-perfused volume after treatment ranged from 1 to 27 ml and was unchanged or decreased in all but one patient at 30 days follow-up. There were no major adverse events. In our 3T magnet the system was able to heat tissue and induce areas of non-enhancement within uterine fibroids without major complications. Clinical benefit remains to be proven.

  6. Molecular MRI differentiation between primary central nervous system lymphomas and high-grade gliomas using endogenous protein-based amide proton transfer MR imaging at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shanshan [Southern Medical University, Department of Radiology, Zhujiang Hospital, Guangzhou, Guangdong (China); Johns Hopkins University School of Medicine, Department of Radiology, Baltimore, MD (United States); Yu, Hao; Wang, Xianlong; Lu, Shilong; Feng, Lyujin; Wen, Zhibo [Southern Medical University, Department of Radiology, Zhujiang Hospital, Guangzhou, Guangdong (China); Li, Yufa [Southern Medical University, Department of Pathology, Zhujiang Hospital, Guangzhou, Guangdong (China); Zhang, Yi; Heo, Hye-Young; Lee, Dong-Hoon; Zhou, Jinyuan [Johns Hopkins University School of Medicine, Department of Radiology, Baltimore, MD (United States)

    2016-01-15

    To show the ability of using the amide proton transfer-weighted (APTW) MRI signals as imaging biomarkers to differentiate primary central nervous system lymphomas (PCNSLs) from high-grade gliomas (HGGs). Eleven patients with lymphomas and 21 patients with HGGs were examined. Magnetization-transfer (MT) spectra over an offset range of ±6 ppm and the conventional MT ratio (MTR) at 15.6 ppm were acquired. The APTW signals, total chemical-exchange-saturation-transfer signal (integral between 0 and 5 ppm, CEST{sub total}), and MTR signal were obtained and compared between PCNSLs and HGGs. The diagnostic performance was assessed with the receiver operating characteristic (ROC) curve analysis. The PCNSLs usually showed more homogeneous APTW hyperintensity (spatially compared to normal brain tissue) than the HGGs. The APTW{sub max}, APTW{sub max-min} and CEST{sub total} signal intensities were significantly lower (P < 0.05, 0.001 and 0.05, respectively), while the APTW{sub min} and MTR were significantly higher (both P < 0.01) in PCNSL lesions than in HGG lesions. The APTW values in peritumoral oedema were significantly lower for PCNSLs than for HGGs (P < 0.01). APTW{sub max-min} had the highest area under the ROC curve (0.963) and accuracy (94.1 %) in differentiating PCNSLs from HGGs. The protein-based APTW signal would be a valuable MRI biomarker by which to identify PCNSLs and HGGs presurgically. (orig.)

  7. 3 Tesla proton MRI for the diagnosis of pneumonia/lung infiltrates in neutropenic patients with acute myeloid leukemia: initial results in comparison to HRCT.

    Science.gov (United States)

    Attenberger, U I; Morelli, J N; Henzler, T; Buchheidt, D; Fink, C; Schoenberg, S O; Reichert, M

    2014-01-01

    To evaluate the diagnostic accuracy of 3 Tesla proton MRI for the assessment of pneumonia/lung infiltrates in neutropenic patients with acute myeloid leukemia. In a prospective study, 3 Tesla MRI was performed in 19 febrile neutropenic patients (5 women, 14 men; mean age 61 years ± 14.2; range 23-77 years). All patients underwent high-resolution CT less than 24h prior to MRI. The MRI protocol (Magnetom Tim Trio, Siemens) included a T2-weighted HASTE sequence (TE/TR: 49 ms/∞, slice thickness 6mm) and a high-resolution 3D VIBE sequence with an ultra-short TETesla MRI with a sensitivity of 82.3% and a specificity of 78.6%, resulting in an overall accuracy of 88% (NPV/PPV 66.7%/89.5%). In 51 lobes (19 of 19 patients), pulmonary abnormalities visualized by MR were judged to be concordant in their location and in the lesion type identified by both readers. In 22 lobes (11 of 19 patients), no abnormalities were present on either MR or HRCT (true negative). In 6 lobes (5 of 19 patients), ground glass opacity areas were detected on MRI but were not visible on HRCT (false positives). In 11 lobes (7 of 19 patients), MRI failed to detect ground glass opacity areas identified by HRCT. However, since the abnormalities were disseminated in these patients, accurate treatment decisions were possible in every case based on MRI. In one case MRI showed a central area of cavitation, which was not visualized by HRCT. Infectious nodules and consolidations can be detected in neutropenic patients with acute myeloid leukemia with a sufficient diagnostic accuracy by 3 Tesla MRI. Detection of ground glass opacity areas is the main limitation of 3-Tesla MRI when compared to HRCT. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Evaluation of 100 brain examinations using a 3 Tesla MR-compatible incubator - safety, handling, and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Sirin, Selma; Goericke, Sophia L.; Kinner, Sonja; Schweiger, Bernd [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Huening, Britta M.; Stein, Anja; Felderhoff-Mueser, Ursula [University Hospital Essen, Department of Neonatology, Division of Pediatrics I, Essen (Germany)

    2013-10-15

    Several studies have revealed the importance of brain imaging in term and preterm infants. The aim of this retrospective study was to review safety, handling, and image quality of MR brain imaging using a new 3 Tesla MR-compatible incubator. Between 02/2011 and 05/2012 100 brain MRIs (84 infants, mean gestational age 32.2 {+-} 4.7 weeks, mean postmenstrual age at imaging 40.6 {+-} 3.4 weeks) were performed using a 3 Tesla MR-compatible incubator with dedicated, compatible head coil. Seventeen examinations (13 infants, mean gestational age 35.1 {+-} 5.4 weeks, mean postmenstrual age at imaging 47.8 {+-} 7.4 weeks) with a standard head coil served as a control. Image analysis was performed by a neuroradiologist and a pediatric radiologist in consensus. All but two patients with known apnea were transferred to the MR unit and scanned without problems. Handling was easier and faster with the incubator; relevant motion artifacts (5.9 vs. 10.8 %) and the need for repetitive sedation (43.0 vs. 86.7 %) were reduced. Considering only images not impaired by motion artifacts, image quality (4.8 {+-} 0.4 vs. 4.3 {+-} 0.8, p = 0.047) and spatial resolution (4.7 {+-} 0.4 vs. 4.2 {+-} 0.6, p = 0.011) of T2-weighted images were scored significantly higher in patients imaged with the incubator. SNR increased significantly (171.6 {+-} 54.5 vs. 80.5 {+-} 19.8, p < 0.001) with the use of the incubator. Infants can benefit from the use of a 3 Tesla MR-compatible incubator because of its safety, easier, and faster handling (compared to standard imaging) and possibility to obtain high-quality MR images even in unstable patients. (orig.)

  9. 3 Tesla proton MRI for the diagnosis of pneumonia/lung infiltrates in neutropenic patients with acute myeloid leukemia: Initial results in comparison to HRCT

    Energy Technology Data Exchange (ETDEWEB)

    Attenberger, U.I., E-mail: ulrike.attenberger@umm.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Morelli, J.N. [Scott and White Hospital, Texas A and M Health Sciences Center, Temple (United States); Henzler, T. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Buchheidt, D. [Department of Hematology and Oncology, University Medical Center Mannheim (Germany); Fink, C. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Department of Radiology, AKH Celle, Celle (Germany); Schoenberg, S.O.; Reichert, M. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany)

    2014-01-15

    Purpose: To evaluate the diagnostic accuracy of 3 Tesla proton MRI for the assessment of pneumonia/lung infiltrates in neutropenic patients with acute myeloid leukemia. Material and methods: In a prospective study, 3 Tesla MRI was performed in 19 febrile neutropenic patients (5 women, 14 men; mean age 61 years ± 14.2; range 23–77 years). All patients underwent high-resolution CT less than 24 h prior to MRI. The MRI protocol (Magnetom Tim Trio, Siemens) included a T2-weighted HASTE sequence (TE/TR: 49 ms/∞, slice thickness 6 mm) and a high-resolution 3D VIBE sequence with an ultra-short TE < 1 ms (TE/TR 0.8/2.9 ms, slice thickness 2 mm). The VIBE sequence was examined before and after intravenous injection of 0.1 mmol/kg gadoterate meglumine (Dotarem, Guerbet). The presence of pulmonary abnormalities, their location within the lung, and lesion type (nodules, consolidations, glass opacity areas) were analyzed by one reader and compared to the findings of HRCT, which was evaluated by a second independent radiologist who served as the reference standard. The findings were compared per lobe in each patient and rated as true positive (TP) findings if all three characteristics (presence, location, and lesion type) listed above were concordant to HRCT. Results: Pulmonary abnormalities were characterized by 3 Tesla MRI with a sensitivity of 82.3% and a specificity of 78.6%, resulting in an overall accuracy of 88% (NPV/PPV 66.7%/89.5%). In 51 lobes (19 of 19 patients), pulmonary abnormalities visualized by MR were judged to be concordant in their location and in the lesion type identified by both readers. In 22 lobes (11 of 19 patients), no abnormalities were present on either MR or HRCT (true negative). In 6 lobes (5 of 19 patients), ground glass opacity areas were detected on MRI but were not visible on HRCT (false positives). In 11 lobes (7 of 19 patients), MRI failed to detect ground glass opacity areas identified by HRCT. However, since the abnormalities were

  10. Imaging Findings of Brain Death on 3-Tesla MRI

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Chul Ho [Dept. of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Hwa Pyung [Dept. of Occupational and Environmental Medicine, CHA Gumi Medical Center, CHA University, Gumi (Korea, Republic of); Park, Jun Beom [Dept. of Radiology, Korean Armed Force Daejeon Hospital, Daejeon (Korea, Republic of); Chang, Hyuk Won; Kim, Easlmaan; Park, Ui Jun; Kim, Hyoung Tae [Keimyung University College of Medicine, Dongsan Medical Center, Daegu (Korea, Republic of); Kim, Eun Hee [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Ku, Jeong Hun [Dept. of Biomedical Engineering, Keimyung University College of Medicine, Daegu (Korea, Republic of)

    2012-09-15

    To demonstrate the usefulness of 3-tesla (3T) magnetic resonance imaging (MRI) including T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), time-of-flight (TOF) magnetic resonance angiography (MRA), T2*-weighted gradient recalled echo (GRE), and susceptibility weighted imaging (SWI) in diagnosing brain death. Magnetic resonance imaging findings for 10 patients with clinically verified brain death (group I) and seven patients with comatose or stuporous mentality who did not meet the clinical criteria of brain death (group II) were retrospectively reviewed. Tonsilar herniation and loss of intraarterial flow signal voids (LIFSV) on T2WI were highly sensitive and specific findings for the diagnosis of brain death (p < 0.001 and < 0.001, respectively). DWI, TOF-MRA, and GRE findings were statistically different between the two groups (p = 0.015, 0.029, and 0.003, respectively). However, cortical high signal intensities in T2WI and SWI findings were not statistically different between the two group (p = 0.412 and 1.0, respectively). T2-weighted imaging, DWI, and MRA using 3T MRI may be useful for diagnosing brain death. However, SWI findings are not specific due to high false positive findings.

  11. 3-Tesla MRI: Beneficial visualization of the meniscofemoral ligaments?

    Science.gov (United States)

    Ebrecht, Johanna; Krasny, Andrej; Hartmann, Dinah Maria; Rückbeil, Marcia Viviane; Ritz, Thomas; Prescher, Andreas

    2017-10-01

    Recent investigations have confirmed an important stabilizing and protective function of the meniscofemoral ligaments (MFLs) to the knee joint and suggest a clinical relevance. Concerning their incidences, however, there have been discrepancies between data acquired from cadaveric studies and MRI data using 0.3- to 1.5-Tesla field strengths probably due to lower resolution. This study aims to investigate whether imaging with 3-Tesla magnetic resonance imaging (3-T MRI) is beneficial in gaining information regarding the ligaments' incidence, length, width and anatomic variation. 3-T MRI images of 448 patients (224 males, 224 females, with, respectively, 32 patients of each sex in the age groups: 0-20, 21-30, 31-40, 41-50, 51-60, 61-70, >70years) were retrospectively reviewed. The influence of the parameters 'sex' and 'age' was determined. Whereas 71% of the patients had at least one MFL, 22% had an anterior MFL (aMFL), 53% had a posterior MFL (pMFL) and five percent had coexisting ligaments. The pMFLs were more likely to be present in female patients (P<0.05) but if so, they were longer in the males (P<0.05). The pMFL was categorized according to its insertion on the medial femoral condyle. 3-T MRI enables an excellent illustration of the anatomic variations of pMFLs. By modifying an anatomic classification for radiological use we measured lengths and widths of the MFLs without any difficulties. Despite its increased resolution, 3-T MRI lends no diagnostic benefit in visualizing the course of the aMFL or filigree coexisting ligaments as compared to MRI at lower field strengths. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Diagnostic usefulness of 3 tesla MRI of the brain for cushing disease in a child.

    Science.gov (United States)

    Ono, Erina; Ozawa, Ayako; Matoba, Kaori; Motoki, Takanori; Tajima, Asako; Miyata, Ichiro; Ito, Junko; Inoshita, Naoko; Yamada, Syozo; Ida, Hiroyuki

    2011-10-01

    It is sometimes difficult to confirm the location of a microadenoma in Cushing disease. Recently, we experienced an 11-yr-old female case of Cushing disease with hyperprolactinemia. She was referred to our hospital because of decrease of height velocity with body weight gain. On admission, she had typical symptoms of Cushing syndrome. Although no pituitary microadenomas were detected on 1.5 Tesla MRI of the brain, endocrinological examinations including IPS and CS sampling were consistent with Cushing disease with hyperprolactinemia. Oral administration of methyrapone instead of neurosurgery was started after discharge, but subsequent 3 Tesla MRI of the brain clearly demonstrated a 3-mm less-enhanced lesion in the left side of the pituitary gland. Finally, transsphenoidal surgery was performed, and a 3.5-mm left-sided microadenoma was resected. Compared with 1.5 Tesla MRI, 3 Tesla MRI offers the advantage of a higher signal to noise ratio (SNR), which provides higher resolution and proper image quality. Therefore, 3 Tesla MRI is a very useful tool to localize microadenomas in Cushing disease in children as well as in adults. It will be the first choice of radiological examinations in suspected cases of Cushing disease.

  13. Blood oxygen-level dependent functional assessment of cerebrovascular reactivity: Feasibility for intraoperative 3 Tesla MRI.

    Science.gov (United States)

    Fierstra, Jorn; Burkhardt, Jan-Karl; van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Pangalu, Athina; Kocian, Roman; Neidert, Marian Christoph; Valavanis, Antonios; Regli, Luca; Bozinov, Oliver

    2017-02-01

    To assess the feasibility of functional blood oxygen-level dependent (BOLD) MRI to evaluate intraoperative cerebrovascular reactivity (CVR) at 3 Tesla field strength. Ten consecutive neurosurgical subjects scheduled for a clinical intraoperative MRI examination were enrolled in this study. In addition to the clinical protocol a BOLD sequence was implemented with three cycles of 44 s apnea to calculate CVR values on a voxel-by-voxel basis throughout the brain. The CVR range was then color-coded and superimposed on an anatomical volume to create high spatial resolution CVR maps. Ten subjects (mean age 34.8 ± 13.4; 2 females) uneventfully underwent the intraoperative BOLD protocol, with no complications occurring. Whole-brain CVR for all subjects was (mean ± SD) 0.69 ± 0.42, whereas CVR was markedly higher for tumor subjects as compared to vascular subjects, 0.81 ± 0.44 versus 0.33 ± 0.10, respectively. Furthermore, color-coded functional maps could be robustly interpreted for a whole-brain assessment of CVR. We demonstrate that intraoperative BOLD MRI is feasible in creating functional maps to assess cerebrovascular reactivity throughout the brain in subjects undergoing a neurosurgical procedure. Magn Reson Med 77:806-813, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  14. Clinical correlates of thalamus volume deficits in anti-psychotic-naïve schizophrenia patients: A 3-Tesla MRI study.

    Science.gov (United States)

    Rao, Naren P; Kalmady, Sunil; Arasappa, Rashmi; Venkatasubramanian, Ganesan

    2010-07-01

    Thalamus, the sensory and motor gateway to the cortex, plays an important role in cognitive and perceptual disturbances in schizophrenia. Studies examining the volume of the thalamus in schizophrenia have reported conflicting findings due to the presence of potential confounding factors such as low-resolution imaging and anti-psychotics. The thalamus volume in anti-psychotic-naïve patients determined using high-resolution 3-Tesla magnetic resonance imaging (MRI) has not yet been examined. Using 3-Tesla MRI, this study for the first time examined anti-psychotic-naïve schizophrenia patients (n=18; M:F:11:7) in comparison with healthy controls (n=19;M:F:9:10) group-matched for age, sex, handedness, education, and socioeconomic status. The volume of the thalamus was measured using a three-dimensional, interactive, semi-automated analysis with good inter-rater and intra-rater reliability. Psychopathology was assessed using the Scale for Assessment of Negative Symptoms (SANS) and the Scale for Assessment of Positive Symptoms (SAPS). Right, left, and total thalamus volumes of patients were significantly smaller than those of controls after controlling for the potential confounding effect of intracranial volume. Thalamus volumes had significant positive correlation with positive symptoms score (SAPS) and significant negative correlation with negative symptoms score (SANS). Thalamus volume deficits in anti-psychotic-naïve schizophrenia patients support a neurodevelopmental pathogenesis. The contrasting correlation of thalamus volume deficits with psychopathology scores suggests that contrasting pruning aberrations underlie symptom genesis in schizophrenia.

  15. Assessment of MRI Issues at 3 Tesla for a New Metallic Tissue Marker.

    Science.gov (United States)

    Cronenweth, Charlotte M; Shellock, Frank G

    2015-01-01

    Purpose. To assess the MRI issues at 3 Tesla for a metallic tissue marker used to localize removal areas of tissue abnormalities. Materials and Methods. A newly designed, metallic tissue marker (Achieve Marker, CareFusion, Vernon Hills, IL) used to mark biopsy sites, particularly in breasts, was assessed for MRI issues which included standardized tests to determine magnetic field interactions (i.e., translational attraction and torque), MRI-related heating, and artifacts at 3 Tesla. Temperature changes were determined for the marker using a gelled-saline-filled phantom. MRI was performed at a relatively high specific absorption rate (whole body averaged SAR, 2.9-W/kg). MRI artifacts were evaluated using T1-weighted, spin echo and gradient echo pulse sequences. Results. The marker displayed minimal magnetic field interactions (2-degree deflection angle and no torque). MRI-related heating was only 0.1°C above background heating (i.e., the heating without the tissue marker present). Artifacts seen as localized signal loss were relatively small in relation to the size and shape of the marker. Conclusions. Based on the findings, the new metallic tissue marker is acceptable or "MR Conditional" (using current labeling terminology) for a patient undergoing an MRI procedure at 3 Tesla or less.

  16. Evaluation of MRI issues at 3-Tesla for a transcatheter aortic valve replacement (TAVR) bioprosthesis.

    Science.gov (United States)

    Saeedi, Mahrad; Thomas, Asish; Shellock, Frank G

    2015-05-01

    Replacement of the aortic heart valve typically requires open-heart surgery. A new transcatheter aortic valve replacement (TAVR) bioprosthesis made from metallic material was recently developed that is an advantageous alternative insofar as it is implanted using a minimally invasive procedure. Because of the presence of metal, there are safety issues related to MRI. Therefore, the purpose of this study was to use standardized testing techniques to evaluate MRI issues for this TAVR bioprosthesis in association with a 3-Tesla MR system. The TAVR bioprosthesis (Hydra Aortic Valve, Percutaneous Heart Valve Prosthesis, Vascular Innovations Company, Ltd, Thailand) was evaluated for magnetic field interactions (translational attraction and torque), MRI-related heating at a relative high specific absorption rate level (whole body average SAR, 2.9-W/kg), and artifacts (T1-weighted, spin echo, and gradient echo pulse sequences) at 3-Tesla. The TAVR bioprosthesis demonstrated negligible magnetic field interactions (deflection angle, 3-degrees; torque, 0) and minimal heating (maximum temperature rise, 2.5°C; background temperature rise, 1.7°C). Artifacts were relatively small in relation to the size and shape of the implant. The TAVR bioprosthesis that was evaluated in this investigation is acceptable, or using current MRI terminology "MR Conditional", for a patient undergoing MRI at 3-Tesla or less. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Detailed imaging of the normal anatomy and pathologic conditions of the cavernous region at 3 Tesla using a contrast-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Linn, Jennifer; Peters, Friederike; Lummel, Nina; Brueckmann, Hartmut; Yousry, Indra [University Hospital Munich, Department of Neuroradiology, Munich (Germany); Schankin, Christoph [University Hospital Munich, Department of Neurology, Munich (Germany); Rachinger, Walter [University Hospital Munich, Department of Neurosurgery, Munich (Germany)

    2011-12-15

    The purpose of this study was to evaluate the potential of a high-resolution contrast-enhanced magnetic resonance angiography (CE-MRA) at 3 Tesla for the delineation of the cavernous sinus (CS) anatomy both under normal and under pathological conditions. Fifteen patients without pathologies in the CS and ten patients with pituitary adenomas were included. The CE-MRA was performed on a 3-Tesla scanner and analyzed collaboratively by two readers. The cranial nerves (CNs) within the CS, namely CNIII, CNIV, CNV1, CNV2, and CNVI, were identified in both patient groups. In the adenoma patients it was also assessed whether and to which extend the adenoma invaded the CS and the spatial relationship between tumor and CNs was determined. In the patients with normal CS anatomy, CNIII could be identified in 100%, CNIV in 86.7%, and CNV1, CNV2, as well as CNVI in 100% of analyzed sides. Pituitary adenomas invaded the CS unilaterally (right side) in four patients, and bilaterally in six patients. In patients with adenomas, the CN could be identified and differentiated from the tumor in the following percentages: CNIII in 100%, CNIV in 70%, both CNV1 and CNV2 in 90%, and CNVI in 100%. In all these cases, the tumor-nerve spatial relationship could be visualized. 3-Tesla CE-MRA allows detailed imaging of the complex anatomy of the CS and its structures. In adenoma patients, it clearly visualizes the spatial relationship between tumor and CNs, and thus might be helpful to optimize presurgical planning. (orig.)

  18. In vivo high-resolution 7 Tesla MRI shows early and diffuse cortical alterations in CADASIL.

    Science.gov (United States)

    De Guio, François; Reyes, Sonia; Vignaud, Alexandre; Duering, Marco; Ropele, Stefan; Duchesnay, Edouard; Chabriat, Hugues; Jouvent, Eric

    2014-01-01

    Recent data suggest that early symptoms may be related to cortex alterations in CADASIL (Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), a monogenic model of cerebral small vessel disease (SVD). The aim of this study was to investigate cortical alterations using both high-resolution T2* acquisitions obtained with 7 Tesla MRI and structural T1 images with 3 Tesla MRI in CADASIL patients with no or only mild symptomatology (modified Rankin's scale ≤1 and Mini Mental State Examination (MMSE) ≥24). Complete reconstructions of the cortex using 7 Tesla T2* acquisitions with 0.7 mm isotropic resolution were obtained in 11 patients (52.1±13.2 years, 36% male) and 24 controls (54.8±11.0 years, 42% male). Seven Tesla T2* within the cortex and cortical thickness and morphology obtained from 3 Tesla images were compared between CADASIL and control subjects using general linear models. MMSE, brain volume, cortical thickness and global sulcal morphology did not differ between groups. By contrast, T2* measured by 7 Tesla MRI was significantly increased in frontal, parietal, occipital and cingulate cortices in patients after correction for multiple testing. These changes were not related to white matter lesions, lacunes or microhemorrhages in patients having no brain atrophy compared to controls. Seven Tesla MRI, by contrast to state of the art post-processing of 3 Tesla acquisitions, shows diffuse T2* alterations within the cortical mantle in CADASIL whose origin remains to be determined.

  19. Orbitofrontal lobe volume deficits in Antipsychotic-Naive schizophrenia: A 3-Tesla MRI study

    Directory of Open Access Journals (Sweden)

    Behere Rishikesh

    2009-01-01

    Full Text Available Background: Prefrontal cortex deficits have been consistently demonstrated in schizophrenia. The orbitofrontal lobe (OFL, a critical component of the prefrontal cortex, subserves social and neuro-cognitive functions. While these functional impairments are established in schizophrenia, the OFL volume deficits have not been well studied, especially in antipsychotic-naοve patients. Aim: To study OFL volume deficits in antipsychotic-naοve schizophrenia patients in comparison with matched healthy controls using high-resolution 3-tesla (3T magnetic resonance imaging (MRI. Materials and Methods: Fourteen antipsychotic-naοve schizophrenia patients (DSM-IV and 14 age-, sex-, handedness- and education-matched healthy controls were scanned using 3T MRI. Psychopathology was assessed in the patient group using the scale for assessment of negative symptoms and the scale for assessment of positive symptoms (SAPS. The OFL volume was measured using Region of Interest (ROI-based manual morphometry technique, with good inter-rater reliability (intra-class correlation coefficient = 0.98. Results: Total OFL volume was significantly smaller in schizophrenia patients (43.3 ± 9.6 mL in comparison with healthy controls (52.1 ± 12.2 mL after controlling for the potential confounding effects of age, sex and intracranial volume (F = 5.3, P = .03. Duration of untreated psychosis did not correlate significantly with OFL volumes. There was a trend towards significant negative correlation between the left and total OFL volumes and SAPS scores (r = -0.49, P = .06. Conclusion: OFL volume deficits might underlie the pathogenesis of schizophrenia symptoms with possible neuro-developmental origins.

  20. 3D calculations of the Superconducting Super Collider (SSC) 3 Tesla magnet

    Energy Technology Data Exchange (ETDEWEB)

    Lari, R.J.

    1984-01-01

    A 20 TeV Superconducting Super Collider (SSC) proton accelerator is being proposed by the High Energy Physics Community. One proposal would consist of a ring of magnets 164 km in circumference with a field strength of 3 Tesla and would cost 2.7 billion dollars. The magnet consists of stacked steel laminations with superconducting coils. The desired field uniformity is obtained for all fields from 0.2 to 3 Tesla by using three (or more) different pole shapes. These three different laminations are stacked in the order 1-2-3-1-2-3-... creating a truly three dimensional geometry. A three laminated stack 1-2-3 with periodic boundary conditions at 1 and 3 was assigned about 5000 finite elements per lamination and solved using the computer program TOSCA. To check the TOSCA results, the field of each of the three different shaped laminations was calculated separately using periodic boundary conditions and compared to the two dimensional field calculations using TRIM. This was done for a constant permeability of 2000 and using the B-H table for fully annealed 1010 steel. The difference of the field calculations in the region of interest was always less than +-.2%

  1. Optimizing texture measures quantifying bone structures as well as MR-sequences at 3 Tesla: an integrative statistical approach

    Science.gov (United States)

    Raeth, Christoph W.; Mueller, Dirk; Rummeny, Ernst J.; Link, Thomas M.; Vogel, Mika; Koenig, Hartmut; Boehm, Holger; Monetti, Roberto

    2006-03-01

    High resolution MR-scanners working with magnetic field strengths of 3 Tesla are clinically available nowadays. They offer the possibility to obtain 3D images with unprecedented spatial resolution and/or signal-to-noise-ratio (SNR) allowing for an accurate visualization of the trabecular bone structure. It has been demonstrated that scaling indices are well suited to quantify these structures, especially to discriminate between plate-like and rod-like structural elements, which is crucial for the diagnosis of osteoporosis. Until now image quality has mainly been assessed by visual impression or by measures based on the SNR. In this work we present a methodology to assess different MR-sequences with respect to the texture measure that is used later in the image analysis. We acquired for a bone specimen HR-MR-sequences with different spatial resolution and signal to noise ratio. For these data sets we selected two volumes of interest (VOI) of same size located in the trabecular bone and in the background of the image. For both VOIs the scaling indices are calculated for different scale parameters. Subsequently the 'texture contrast' between structure and background is calculated by comparing the probability distributions of the scaling indices using a quadratic distance measure. By means of the contrast the optimal set of scale parameters is determined. By comparing the contrast for the different MR sequences the best suited ones are determined. It turns out that sequences with slightly lower spatial resolution but better signal to noise ration yield a better texture contrast than sequences with the best spatial resolution. The presented methodology offers the possibility to optimize simultaneously texture measures and MR-sequences, which will allow for an adapted and thus optimized analysis of image structures, e.g. trabecular bone, in the HR-MR data.

  2. A functional magnetic resonance imaging study of listening comprehension of languages in human at 3 tesla-comprehension level and activation of the language areas.

    Science.gov (United States)

    Nakai, T; Matsuo, K; Kato, C; Matsuzawa, M; Okada, T; Glover, G H; Moriya, T; Inui, T

    1999-03-19

    Passive listening comprehension of native and non-native language was investigated using high resolution functional magnetic resonance imaging (fMRI) at a static magnetic field strength of 3 tesla. Wernicke's area was activated by comprehensive and non-comprehensive languages indicating that this area is associated with common phonological processing of language. The task with comprehensive but non-native language activated Broca's area and angular gyrus most frequently. The activations in these areas may be related to demand in semantic and syntactic processing in listening comprehension. Supplementary motor area and pre-motor area were activated by comprehensive languages but not by non-comprehensive language. These motor controlling areas may be involved in semantic processing. Listening to comprehensive but non-native language seems to demand more networked co-processing.

  3. A novel computerized algorithm to detect microstructural brainstem pathology in Parkinson's disease using standard 3 Tesla MR imaging.

    Science.gov (United States)

    Boelmans, Kai; Spies, Lothar; Sedlacik, Jan; Fiehler, Jens; Jahn, Holger; Gerloff, Christian; Münchau, Alexander

    2014-10-01

    Increased deposition of α-synuclein in Parkinson's disease (PD) is known to be prominent in the brainstem and discussed to be clinically relevant for motor and non-motor features. Whether structural magnetic resonance imaging is capable to detect degraded tissue microstructure caused by increased deposition of α-synuclein at this predilection site in PD remains unclear. We hypothesize that microstructural degradation in the brainstem leads to a reduced T1 contrast provoking standard tissue segmentation engines to misclassify tissue as additional grey matter in regions predominantly composed of white matter. High-resolution T1-weighted three-dimensional magnetization prepared rapid gradient echo (MPRAGE) imaging at 3 Tesla in fifty-two PD patients with mild-to-moderate disease severity and in forty age- and gender-matched healthy controls was performed. A dedicated computerized algorithm that comprises standard tissue segmentation in combination with a statistical test was set up that evaluates grey matter composition on voxel level. The algorithm detected a single significant cluster of voxels with enhanced grey matter (cluster volume is 1,368 mm(3), p < 0.05 corrected for false discovery rate) in the pontomedullary junction of the brainstem in PD patients as compared to healthy controls. Furthermore, absolute grey matter volume was significantly higher in the brainstem of the PD group compared to healthy controls. We conclude that this cluster may reflect α-synuclein induced microstructural brainstem pathology in PD.

  4. Cortical microinfarcts detected in vivo on 3 tesla MRI : Clinical and radiological correlates

    NARCIS (Netherlands)

    Van Dalen, Jan Willem; Scuric, Eva E M; Van Veluw, Susanne J.; Caan, Matthan W A; Nederveen, Aart J.; Biessels, Geert Jan|info:eu-repo/dai/nl/165576367; Van Gool, Willem A.; Richard, Edo

    2015-01-01

    Background and Purpose-Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. Methods-We evaluated CMIs on 3 Tesla MRI in a populati

  5. Cortical microinfarcts detected in vivo on 3 Tesla MRI: clinical and radiological correlates

    NARCIS (Netherlands)

    Dalen, J.W. van; Scuric, E.E.; Veluw, S.J. van; Caan, M.W.; Nederveen, A.J.; Biessels, G.J.; Gool, W.A. van; Richard, E.

    2015-01-01

    BACKGROUND AND PURPOSE: Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. METHODS: We evaluated CMIs on 3 Tesla MRI in a popula

  6. Cortical microinfarcts detected in vivo on 3 tesla MRI : Clinical and radiological correlates

    NARCIS (Netherlands)

    Van Dalen, Jan Willem; Scuric, Eva E M; Van Veluw, Susanne J.; Caan, Matthan W A; Nederveen, Aart J.; Biessels, Geert Jan; Van Gool, Willem A.; Richard, Edo

    2015-01-01

    Background and Purpose-Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. Methods-We evaluated CMIs on 3 Tesla MRI in a

  7. Cortical microinfarcts detected in vivo on 3 Tesla MRI: clinical and radiological correlates

    NARCIS (Netherlands)

    Dalen, J.W. van; Scuric, E.E.; Veluw, S.J. van; Caan, M.W.; Nederveen, A.J.; Biessels, G.J.; Gool, W.A. van; Richard, E.

    2015-01-01

    BACKGROUND AND PURPOSE: Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. METHODS: We evaluated CMIs on 3 Tesla MRI in a

  8. Cortical microinfarcts detected in vivo on 3 tesla MRI : Clinical and radiological correlates

    NARCIS (Netherlands)

    Van Dalen, Jan Willem; Scuric, Eva E M; Van Veluw, Susanne J.; Caan, Matthan W A; Nederveen, Aart J.; Biessels, Geert Jan; Van Gool, Willem A.; Richard, Edo

    2015-01-01

    Background and Purpose-Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. Methods-We evaluated CMIs on 3 Tesla MRI in a populati

  9. Functional and perfusion magnetic resonance imaging at 3 tesla

    CERN Document Server

    Klarhoefer, M

    2001-01-01

    This thesis deals with the development and optimization of fast magnetic resonance imaging (MRI) methods for non-invasive functional studies of the human brain and perfusion imaging on a 3 Tesla (T) whole body NMR system. The functional MRI (fMRI) experiments performed showed that single-shot multi-echo EPI and spiral imaging techniques provide fast tools to obtain information about T2* distributions during functional activation in the human brain. Both sequences were found to be useful in the separation of different sources contributing to the functional MR signal like inflow or susceptibility effects in the various vascular environments. An fMRI study dealing with the involvement of prefrontal brain regions in movement preparation lead to inconsistent results. It could not be clarified if these were caused by problems during a spatial normalization process of the individual brains or if the functional paradigm, using very short inter-stimulus intervals, was not suited for the problem investigated. Blood flo...

  10. 3-Tesla functional magnetic resonance imaging-guided tumor resection

    Energy Technology Data Exchange (ETDEWEB)

    Hall, W.A. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Depts. of Neurosurgery; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Radiation Oncology; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Radiology; University of Minnesota Medical Center (MMC), Minneapolis, MN (United States); Truwit, C.L. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Radiology; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Pediatrics; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Neurology; Hennepin Country Medical Center, Minneapolis, MN (United States). Dept. of Radiology

    2006-12-15

    Objective: We sought to determine the safety and efficacy of using 3-tesla (T) functional magnetic resonance imaging (fMRI) to guide brain tumor resection. Material and methods: From February 2004 to March 2006, fMRI was performed on 13 patients before surgical resection. Functional imaging was used to identify eloquent cortices for motor (8), speech (3), and motor and speech (2) activation using two different 3-T magnetic resonance (MR) scanners. Surgical resection was accomplished using a 1.5-T intraoperative MR system. Appropriate MR scan sequences were performed intraoperatively to determine and maximize the extent of the surgical resection. Results: Tumors included six oligodendrogliomas, three meningiomas, two astrocytomas and two glioblastomas multiforme. The fMRI data was accurate in all cases. After surgery, two patients had hemiparesis, two had worsening of their speech, and one had worsening of speech and motor function. Neurological function returned to normal in all patients within 1 month. Complete resections were possible in 10 patients (77%). Two patients had incomplete resections because of the proximity of their tumors to functional areas. Biopsy was performed in another patient with an astrocytoma in the motor strip. Conclusion: 3-T fMRI was accurate for locating neurologic function before tumor resection near eloquent cortex. (orig.)

  11. TRICKS Magnetic Resonance Angiography at 3-Tesla for Assessing Whole Lower Extremity Vascular Tree in Patients with High-Grade Critical Limb Ischemia: DSA and TASC II Guidelines Correlations

    Directory of Open Access Journals (Sweden)

    Sheung-Fat Ko

    2012-01-01

    Full Text Available The entire vascular tree of 58 lower extremities with high-grade critical limb ischemia (CLI was assessed with three-station time resolved imaging of contrast kinetics (TRICKS magnetic resonance angiography (T-MRA and correlated with digital subtraction angiography (DSA examinations and Trans-Atlantic Inter-Society Consensus II (TASC II guidelines. Kappa (κ statistics were utilized to evaluate the agreement of stenosis scores (5-point scale; 0 normal to 4 occlusion based on T-MRA and DSA. With DSA as the standard, significant stenosis instances (stenosis score ≥2 among vascular segments were compared. The κ-statistics of image quality (4-point scale; 1 nondiagnostic to 4 excellent of T-MRA and TASC II classification assessed by a radiologist and a vascular surgeon were also evaluated. Among 870 vascular segments, excellent agreement was observed between T-MRA and DSA (mean κ = 0.883 in revealing stenosis (mean stenosis score, 2.1  ±  1.3 versus 2.0  ±  1.3. T-MRA harbored overall high sensitivity (99.5%, specificity (93.6%, positive predictive value (95.4%, negative predictive value (99.6%, and accuracy (97.7% in depicting significant stenosis. Excellent interobserver agreement (mean κ = 0.818 of superb image quality (mean score = 3.5–3.6 of T-MRA and outstanding agreement of TASC II classification of aortoiliac and femoral-popliteal lesions (κ = 0.912–0.917 between two raters further verified the clinical feasibility of T-MRA for treatment planning.

  12. High Resolution Elevation Contours

    Data.gov (United States)

    Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

  13. 3 Tesla MR neurography - technique, interpretation, and pitfalls

    Energy Technology Data Exchange (ETDEWEB)

    Chhabra, Avneesh; Lee, Pearlene P.; Bizzell, Cary; Soldatos, Theodoros [Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States)

    2011-10-15

    MRI has been used for almost two decades for the evaluation of peripheral nerve disorders. This article highlights the relative advantages and disadvantages of 3T MR neurography in the evaluation of peripheral neuropathies. The authors also describe the high-resolution MR neurography technique on 3T MRI, along with the approach to its interpretation that has evolved at one institution. (orig.)

  14. Orthodontic brackets in high field MR imaging: experimental evaluation of magnetic field interactions at 3.0 tesla; Kieferorthopaedische Brackets in der Hochfeld-Magnetresonanz-Tomographie: Experimentelle Beurteilung magnetischer Anziehungs- und Rotationskraefte bei 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Kemper, J.; Adam, G. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Eppendorf, Hamburg (Germany); Klocke, A.; Kahl-Nieke, B. [Poliklinik fuer Kieferorthopaedie, Universitaetsklinikum Eppendorf, Hamburg (Germany)

    2005-12-15

    Purpose: To evaluate static magnetic field interactions for 32 commonly used orthodontic brackets in a 3.0 T magnetic resonance imaging (MRI) system. Materials and methods: 32 orthodontic brackets consisting of a steel alloy (n=27), a cobalt-chromium alloy (n=2), ceramic (n=1), ceramic with a steel slot (n=1), and titanium (n=1) from 13 different manufacturers were tested for magnetic field interactions in a static magnetic field at 3.0 T (Gyroscan Intera 3.0 T, Philips Medical Systems, Best, Netherlands). The magnetic deflection force F{sub Z} [mN] was evaluated by determining the deflection angle {beta}[ ] using the established deflection angle test according to the ASTM guidelines. The magnetic-field-induced rotational force F{sub rot} or torque was qualitatively determined using a 5-point grading scale (0: no torque; +4: very strong torque). Results: In 18 of the 32 brackets, the deflection angle {beta} was found to be > 45 and the translational force exceeded the gravitational force F{sub G} on the particular bracket (F{sub Z}: 1.2-45.7 mN). The translational force F{sub Z} was found to be up to 68.5 times greater than the gravitational force F{sub G} (F{sub Z}/F{sub G}: 1.4-68.5). The rotational force F{sub rot} was correspondingly high (+3/+4) for those brackets. For the remaining 14 objects, the deflection angles were < 45 and the torque measurements ranged from 0 to +2. The static magnetic field did not affect the titanium bracket and the ceramic bracket. No measurable translational and rotational forces were found. (orig.)

  15. In vivo high-resolution 7 Tesla MRI shows early and diffuse cortical alterations in CADASIL.

    Directory of Open Access Journals (Sweden)

    François De Guio

    Full Text Available Recent data suggest that early symptoms may be related to cortex alterations in CADASIL (Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy, a monogenic model of cerebral small vessel disease (SVD. The aim of this study was to investigate cortical alterations using both high-resolution T2* acquisitions obtained with 7 Tesla MRI and structural T1 images with 3 Tesla MRI in CADASIL patients with no or only mild symptomatology (modified Rankin's scale ≤1 and Mini Mental State Examination (MMSE ≥24.Complete reconstructions of the cortex using 7 Tesla T2* acquisitions with 0.7 mm isotropic resolution were obtained in 11 patients (52.1±13.2 years, 36% male and 24 controls (54.8±11.0 years, 42% male. Seven Tesla T2* within the cortex and cortical thickness and morphology obtained from 3 Tesla images were compared between CADASIL and control subjects using general linear models.MMSE, brain volume, cortical thickness and global sulcal morphology did not differ between groups. By contrast, T2* measured by 7 Tesla MRI was significantly increased in frontal, parietal, occipital and cingulate cortices in patients after correction for multiple testing. These changes were not related to white matter lesions, lacunes or microhemorrhages in patients having no brain atrophy compared to controls.Seven Tesla MRI, by contrast to state of the art post-processing of 3 Tesla acquisitions, shows diffuse T2* alterations within the cortical mantle in CADASIL whose origin remains to be determined.

  16. Accuracy of accelerated cine MR imaging at 3 Tesla in longitudinal follow-up of cardiac function

    Energy Technology Data Exchange (ETDEWEB)

    Sandner, Torleif A.; Huber, Armin M.; Theisen, Daniel; Reiser, Maximilian F.; Wintersperger, Bernd J. [Ludwig-Maximilians-University, Department of Clinical Radiology, University Hospitals - Campus Grosshadern, Munich (Germany); Houck, Philip [Texas A and M University Health Science Center, Department of Cardiology, Scott and White Clinic and Hospital, Temple, TX (United States); Runge, Val M.; Sincleair, Spencer [Texas A and M University Health Science Center, Department of Radiology, Scott and White Clinic and Hospital, Temple, TX (United States)

    2008-10-15

    The ability of fast, parallel-imaging-based cine magnetic resonance (MR) to monitor global cardiac function in longitudinal exams at 3 Tesla was evaluated. Seventeen patients with chronic cardiac disease underwent serial cine MR imaging exams (n=3) at 3 Tesla. Data were acquired in short-axis orientation using cine steady-state free precession (SSFP) with a spatial resolution of 2.5 x 1.9 mm{sup 2} at 45 ms temporal resolution. Multislice imaging (three slices/breath-hold) was performed using TSENSE acceleration (R=3) and standard single-slice cine (non-TSENSE) was performed at identical locations in consecutive breath-holds. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) and myocardial mass (MM) of both cine approaches were compared for individual time-points as well as for longitudinal comparison. TSENSE-cine did not show significant differences for EDV (2.6 ml; P=.79), ESV (2.2 ml; P=0.81), EF (-0.3%; P=0.95) and MM (2.4 g; P=0.72) in comparison with non-TSENSE. Longitudinal ANOVA analysis did not reveal significant differences for any parameter, neither for non-TSENSE data (all P>0.7) nor for TSENSE data (all P>0.9). Multifactorial ANOVA showed non-significant differences (all P>0.7) at comparable data variances. Data acquisition was significantly shortened using TSENSE. Threefold accelerated multislice cine at 3 Tesla allows accurate assessment of volumetric LV data and accurate longitudinal monitoring of global LV function at a substantially shorter overall examination time. (orig.)

  17. Ultra high resolution tomography

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  18. [Reproducibility and accuracy in the morphometric and mechanical quantification of trabecular bone from 3 Tesla magnetic resonance images].

    Science.gov (United States)

    Alberich-Bayarri, A; Martí-Bonmatí, L; Sanz-Requena, R; Sánchez-González, J; Hervás Briz, V; García-Martí, G; Pérez, M Á

    2014-01-01

    We used an animal model to analyze the reproducibility and accuracy of certain biomarkers of bone image quality in comparison to a gold standard of computed microtomography (μCT). We used magnetic resonance (MR) imaging and μCT to study the metaphyses of 5 sheep tibiae. The MR images (3 Teslas) were acquired with a T1-weighted gradient echo sequence and an isotropic spatial resolution of 180μm. The μCT images were acquired using a scanner with a spatial resolution of 7.5μm isotropic voxels. In the preparation of the images, we applied equalization, interpolation, and thresholding algorithms. In the quantitative analysis, we calculated the percentage of bone volume (BV/TV), the trabecular thickness (Tb.Th), the trabecular separation (Tb.Sp), the trabecular index (Tb.N), the 2D fractal dimension (D(2D)), the 3D fractal dimension (D(3D)), and the elastic module in the three spatial directions (Ex, Ey and Ez). The morphometric and mechanical quantification of trabecular bone by MR was very reproducible, with percentages of variation below 9% for all the parameters. Its accuracy compared to the gold standard (μCT) was high, with errors less than 15% for BV/TV, D(2D), D(3D), and E(app)x, E(app)y and E(app)z. Our experimental results in animals confirm that the parameters of BV/TV, D(2D), D(3D), and E(app)x, E(app)y and E(app)z obtained by MR have excellent reproducibility and accuracy and can be used as imaging biomarkers for the quality of trabecular bone. Copyright © 2013 SERAM. Published by Elsevier Espana. All rights reserved.

  19. Non-contrast-enhanced MR angiography at 3 Tesla in patients with advanced peripheral arterial occlusive disease.

    Directory of Open Access Journals (Sweden)

    Kolja M Thierfelder

    Full Text Available PURPOSE: The aim of this study was to assess the diagnostic performance of ECG-gated non-contrast-enhanced quiescent interval single-shot (QISS magnetic resonance angiography at a magnetic field strength of 3 Tesla in patients with advanced peripheral arterial occlusive disease (PAOD. METHOD AND MATERIALS: A total of 21 consecutive patients with advanced PAOD (Fontaine stage IIb and higher referred for peripheral magnetic resonance angiography (MRA were included. Imaging was performed on a 3 T whole body MR. Image quality and stenosis diameter were evaluated in comparison to contrast-enhanced continuous table and TWIST MRA (CE-MRA as standard of reference. QISS images were acquired with a thickness of 1.5 mm each (high-resolution QISS, HR-QISS. Two blinded readers rated the image quality and the degree of stenosis for both HR-QISS and CE-MRA in 26 predefined arterial vessel segments on 5-point Likert scales. RESULTS: With CE-MRA as the reference standard, HR-QISS showed high sensitivity (94.1%, specificity (97.8%, positive (95.1%, and negative predictive value (97.2% for the detection of significant (≥ 50% stenosis. Interreader agreement for stenosis assessment of both HR-QISS and CE-MRA was excellent (κ-values of 0.951 and 0.962, respectively. As compared to CR-MRA, image quality of HR-QISS was significantly lower for the distal aorta, the femoral and iliac arteries (each with p<0.01, while no significant difference was found in the popliteal (p = 0.09 and lower leg arteries (p = 0.78. CONCLUSION: Non-enhanced ECG-gated HR-QISS performs very well in subjects with severe PAOD and is a good alternative for patients with a high risk of nephrogenic systemic fibrosis.

  20. Non-contrast-enhanced MR angiography at 3 Tesla in patients with advanced peripheral arterial occlusive disease.

    Science.gov (United States)

    Thierfelder, Kolja M; Meimarakis, Georgios; Nikolaou, Konstantin; Sommer, Wieland H; Schmitt, Peter; Kazmierczak, Philipp M; Reiser, Maximilian F; Theisen, Daniel

    2014-01-01

    The aim of this study was to assess the diagnostic performance of ECG-gated non-contrast-enhanced quiescent interval single-shot (QISS) magnetic resonance angiography at a magnetic field strength of 3 Tesla in patients with advanced peripheral arterial occlusive disease (PAOD). A total of 21 consecutive patients with advanced PAOD (Fontaine stage IIb and higher) referred for peripheral magnetic resonance angiography (MRA) were included. Imaging was performed on a 3 T whole body MR. Image quality and stenosis diameter were evaluated in comparison to contrast-enhanced continuous table and TWIST MRA (CE-MRA) as standard of reference. QISS images were acquired with a thickness of 1.5 mm each (high-resolution QISS, HR-QISS). Two blinded readers rated the image quality and the degree of stenosis for both HR-QISS and CE-MRA in 26 predefined arterial vessel segments on 5-point Likert scales. With CE-MRA as the reference standard, HR-QISS showed high sensitivity (94.1%), specificity (97.8%), positive (95.1%), and negative predictive value (97.2%) for the detection of significant (≥ 50%) stenosis. Interreader agreement for stenosis assessment of both HR-QISS and CE-MRA was excellent (κ-values of 0.951 and 0.962, respectively). As compared to CR-MRA, image quality of HR-QISS was significantly lower for the distal aorta, the femoral and iliac arteries (each with p<0.01), while no significant difference was found in the popliteal (p = 0.09) and lower leg arteries (p = 0.78). Non-enhanced ECG-gated HR-QISS performs very well in subjects with severe PAOD and is a good alternative for patients with a high risk of nephrogenic systemic fibrosis.

  1. High-resolution headlamp

    Science.gov (United States)

    Gut, Carsten; Cristea, Iulia; Neumann, Cornelius

    2016-04-01

    The following article shall describe how human vision by night can be influenced. At first, front lighting systems that are already available on the market will be described, followed by their analysis with respect to the positive effects on traffic safety. Furthermore, how traffic safety by night can be increased since the introduction of high resolution headlamps shall be discussed.

  2. Experimental autoimmune encephalomyelitis (EAE): lesion visualization on a 3 tesla Clinical whole-body system after intraperitoneal contrast injection

    Energy Technology Data Exchange (ETDEWEB)

    Heckl, S.; Naegele, T.; Klose, U. [Dept. of Neuroradiology, Medical School, Univ. of Tuebingen (Germany); Herrmann, M.; Gaertner, S.; Weissert, R. [Dept. of Neurology, Medical School, Univ. of Tuebingen (Germany); Schick, F. [Dept. of Radiology, Medical School, Univ. of Tuebingen (Germany); Kueker, W. [Dept. of Neuroradiology, Medical School, Univ. of Tuebingen (Germany); Dept. of Neuroradiology, Radcliffe Infirmary, Oxford, England (United Kingdom)

    2004-11-01

    Purpose: To investigate the intravital visibility of CNS lesions in rats with experimental autoimmune encephalomyelitis (EAE), the animal correlate of multiple sclerosis, using a 3-Tesla (T) wholebody MR system. Materials and Methods: Three healthy Dark Agouti (DA) rats and 16 DA rats with clinical signs of EAE were examined on a 3T whole body-system using a normal wrist coil. In total, 25 examinations were preformed using T2- and T1-weighted images in transverse and sagittal orientation with a slice thickness of 2 mm or 1 mm (voxel size up to 0.2 x 0.2 x 1 mm). Sedation was achieved by intraperitoneal injection of ketamine and xylazine. In addition, T1-weighted images were obtained after the instillation of 1.0 ml of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) (0.5 mmol/ml) into the peritoneal cavity. Results: T2- and T1-weighted images of the brain and spinal cord with high spatial and contrast resolution could be obtained in all animals. The anatomical details of the olfactory bulb glomeruli, cerebellum foliae, ventricles and corpus callosum were clearly visible. The EAE lesions presented as hyperintense area in T2-weighted images and could be demonstrated in all clinically affected animals by MRI and histologically verified. In total, the 16 affected rats had 28 cerebral and 2 spinal cord lesions (range 1 to 4, median 2). Contrast enhancement was noted in 12 animals and ranked as severe in ten and moderate in two cases. No adverse effects were noted due to sedation or intraperitoneal contrast injection. Conclusions: The intravital demonstration of cerebral and spinal cord EAE lesions in rats is possible on a 3T whole-body MR scanner using a normal wrist coil. Intraperitoneal injection of ketamine/xylazine and contrast agent is an easy, safe and effective procedure in rats. (orig.)

  3. High Resolution Acoustical Imaging

    Science.gov (United States)

    1989-05-01

    1028 (September 1982). 26 G. Arfken , Mathematical Methods for Physicists (Academic Press, New York, 1971), 2nd printing, pp.662-666. 27 W. R. Hahn...difference in the approach used by the two methods , as noted in the previous paragraph, forming a direct mathematical com- parison may be impossible...examines high resolution methods which use a linear array to locate stationary objects which have scattered the fressure waves. Several;- new methods

  4. High resolution differential thermometer

    Directory of Open Access Journals (Sweden)

    Gotra Z. Yu.

    2009-11-01

    Full Text Available Main schematic solutions of differential thermometers with measurement resolution about 0.001°C are considered. Differential temperature primary transducer realized on a transistor differential circuit in microampere mode. Analytic calculation and schematic mathematic simulation of primary transducer are fulfilled. Signal transducer is realized on a high precision Zero-Drift Single-Supply Rail-to-Rail operation amplifier AD8552 and 24-Bit S-D microconverter ADuC834.

  5. Saturn's rings - high resolution

    Science.gov (United States)

    1981-01-01

    Voyager 2 obtained this high-resolution picture of Saturn's rings Aug. 22, when the spacecraft was 4 million kilometers (2.5 million miles) away. Evident here are the numerous 'spoke' features, in the B-ring; their very sharp, narrow appearance suggests short formation times. Scientists think electromagnetic forces are responsible in some way for these features, but no detailed theory has been worked out. Pictures such as this and analyses of Voyager 2's spoke movies may reveal more clues about the origins of these complex structures. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  6. High Resolution Laboratory Spectroscopy

    CERN Document Server

    Brünken, Sandra

    2016-01-01

    In this short review we will highlight some of the recent advancements in the field of high-resolution laboratory spectroscopy that meet the needs dictated by the advent of highly sensitive and broadband telescopes like ALMA and SOFIA. Among these is the development of broadband techniques for the study of complex organic molecules, like fast scanning conventional absorption spectroscopy based on multiplier chains, chirped pulse instrumentation, or the use of synchrotron facilities. Of similar importance is the extension of the accessible frequency range to THz frequencies, where many light hydrides have their ground state rotational transitions. Another key experimental challenge is the production of sufficiently high number densities of refractory and transient species in the laboratory, where discharges have proven to be efficient sources that can also be coupled to molecular jets. For ionic molecular species sensitive action spectroscopic schemes have recently been developed to overcome some of the limita...

  7. High Time Resolution Astrophysics

    CERN Document Server

    Phelan, Don; Shearer, Andrew

    2008-01-01

    High Time Resolution Astrophysics (HTRA) is an important new window to the universe and a vital tool in understanding a range of phenomena from diverse objects and radiative processes. This importance is demonstrated in this volume with the description of a number of topics in astrophysics, including quantum optics, cataclysmic variables, pulsars, X-ray binaries and stellar pulsations to name a few. Underlining this science foundation, technological developments in both instrumentation and detectors are described. These instruments and detectors combined cover a wide range of timescales and can measure fluxes, spectra and polarisation. These advances make it possible for HTRA to make a big contribution to our understanding of the Universe in the next decade.

  8. High-resolution intravascular magnetic resonance quantification of atherosclerotic plaque at 3T

    Directory of Open Access Journals (Sweden)

    Qian Di

    2012-03-01

    Full Text Available Abstract Background The thickness of fibrous caps (FCT of atherosclerotic lesions is a critical factor affecting plaque vulnerability to rupture. This study tests whether 3 Tesla high-resolution intravascular cardiovascular magnetic resonance (CMR employing tiny loopless detectors can identify lesions and accurately measure FCT in human arterial specimens, and whether such an approach is feasible in vivo using animal models. Methods Receive-only 2.2 mm and 0.8 mm diameter intravascular loopless CMR detectors were fabricated for a clinical 3 Tesla MR scanner, and the absolute signal-to-noise ratio determined. The detectors were applied in a two-step protocol comprised of CMR angiography to identify atherosclerotic lesions, followed by high-resolution CMR to characterize FCT, lesion size, and/or vessel wall thickness. The protocol was applied in fresh human iliac and carotid artery specimens in a human-equivalent saline bath. Mean FCT measured by 80 μm intravascular CMR was compared with histology of the same sections. In vivo studies compared aortic wall thickness and plaque size in healthy and hyperlipidemic rabbit models, with post-mortem histology. Results Histology confirmed plaques in human specimens, with calcifications appearing as signal voids. Mean FCT agreed with histological measurements within 13% on average (correlation coefficient, R = 0.98; Bland-Altman analysis, -1.3 ± 68.9 μm. In vivo aortic wall and plaque size measured by 80 μm intravascular CMR agreed with histology. Conclusion Intravascular 3T CMR with loopless detectors can both locate atherosclerotic lesions, and accurately measure FCT at high-resolution in a strategy that appears feasible in vivo. The approach shows promise for quantifying vulnerable plaque for evaluating experimental therapies.

  9. Sacrotuberous Ligament Healing following Surgical Division during Transgluteal Pudendal Nerve Decompression: A 3-Tesla MR Neurography Study

    Science.gov (United States)

    Fritz, Jan; Fritz, Benjamin; Dellon, A. Lee

    2016-01-01

    Pelvic pain due to chronic pudendal nerve (PN) compression, when treated surgically, is approached with a transgluteal division of the sacrotuberous ligament (STL). Controversy exists as to whether the STL heals spontaneously or requires grafting. Therefore, the aim of this study was to determine how surgically divided and unrepaired STL heal. A retrospective evaluation of 10 patients who had high spatial resolution 3-Tesla magnetic resonance imaging (3T MRI) exams of the pelvis was done using an IRB-approved protocol. Each patient was referred for residual pelvic pain after a transgluteal STL division for chronic pudendal nerve pain. Of the 10 patients, 8 had the STL divided and not repaired, while 2 had the STL divided and reconstructed with an allograft tendon. Of the 8 that were left unrepaired, 6 had bilateral surgery. Outcome variables included STL integrity and thickness. Normative data for the STL were obtained through a control group of 20 subjects. STL integrity and thickness were measured directly on 3 T MR Neurography images, by two independent Radiologists. The integrity and thickness of the post-surgical STL was evaluated 39 months (range, 9–55) after surgery. Comparison was made with the native contra-lateral STL in those who had unilateral STL division, and with normal, non-divided STL of subjects of the control group. The normal STL measured 3 mm (minimum and maximum of absolute STL thickness, 2–3 mm). All post-operative STL were found to be continuous regardless of the surgical technique used. Measured at level of Alcock’s canal in the same plane as the obturator internus tendon posterior to the ischium, the mean anteroposterior STL diameter was 5 mm (range, 4–5 mm) in the group of prior STL division without repair and 8 mm (range, 8–9 mm) in the group with the STL reconstructed with grafts (p<0.05). The group of healed STLs were significantly thicker than the normal STL (p<0.05). We conclude that a surgically divided STL will heal

  10. Differentiation of brain metastases by percentagewise quantification of intratumoral-susceptibility-signals at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Radbruch, Alexander, E-mail: Alexander.Radbruch@med.uni-heidelberg.de [Department of Neuroradiology, University of Heidelberg Medical Center (Germany); Department of Radiology, German Cancer Research Center (DKFZ) (Germany); Graf, Markus, E-mail: m.graf@dkfz.de [Software Development for Integrated Diagnosis and Therapy, German Cancer Research Center (DKFZ) (Germany); Kramp, Linda, E-mail: linda.kramp@gmx.de [Department of Neuroradiology, University of Heidelberg Medical Center (Germany); Wiestler, Benedikt, E-mail: b.wiestler@dkfz.de [Department of Neurooncology, University of Heidelberg Medical Center (Germany); Floca, Ralf, E-mail: r.floca@dkfz.de [Software Development for Integrated Diagnosis and Therapy, German Cancer Research Center (DKFZ) (Germany); Bäumer, Philipp, E-mail: philipp.baeumer@med.uni-heidelberg.de [Department of Neuroradiology, University of Heidelberg Medical Center (Germany); Roethke, Matthias, E-mail: m.roethke@dkfz.de [Department of Radiology, German Cancer Research Center (DKFZ) (Germany); Stieltjes, Bram, E-mail: b.stieltjes@dkfz.de [Department of Radiology, German Cancer Research Center (DKFZ) (Germany); Schlemmer, Heinz-Peter, E-mail: h.schlemmer@dkfz.de [Department of Radiology, German Cancer Research Center (DKFZ) (Germany); Heiland, Sabine, E-mail: sabine.heiland@med.uni-heidelberg.de [Department of Neuroradiology, University of Heidelberg Medical Center (Germany); Bendszus, Martin, E-mail: martin.bendszus@med.uni-heidelberg.de [Department of Neuroradiology, University of Heidelberg Medical Center (Germany)

    2012-12-15

    Introduction: Evaluation of intratumoral-susceptibility-signals (ITSS) in susceptibility-weighted-imaging (SWI) has been reported to improve diagnostic performance for solitary enhancing brain lesions. Due to the distinct morphologic variability of ITSS, standardized evaluation proved to be difficult. We analyzed, if a new postprocessing method using percentagewise quantification (PQ) of ITSS enables differentiation between different entities of cerebral metastases and may thus improve differential diagnosis in cases of unknown primary. Materials and methods: SWI and contrast enhanced T1-weighted MR images were acquired from 84 patients with intracerebral metastases (20 patients with mamma carcinoma (MC), 15 patients with malignant melanoma (MM), 49 patients with bronchial carcinoma (BC)) at 3 Tesla MR. Images were co-registered and enhancing lesions were delineated on T1-weighted images and the outline transferred to the corresponding SWI map. All voxels within the lesion presenting values below a reference value placed in the ventricular system were determined and percentagewise calculated. Results: Diagnostic performance of percentagewise quantification (PQ) of ITSS, as determined with area under the receiver operating characteristic curve (AUC) was excellent (AUC = 0.96; 95% confidence interval (CI) 0.90, 1.00) to discriminate MM from MC, good for the discrimination of MM and BC (AUC = 0.81, 95% CI 0.70, 0.92) and poor for the discrimination of MC and BC (AUC = 0.60; 95% CI 0.47, 0.73). Conclusion: PQ is a new approach for the assessment of SWI that can be used for differential diagnosis of intracerebral metastases. Metastases of MM and MC or BC can be distinguished with high sensitivity and specificity.

  11. High Resolution Formaldehyde Photochemistry

    Science.gov (United States)

    Ernest, C. T.; Bauer, D.; Hynes, A. J.

    2010-12-01

    Formaldehyde (HCHO) is the most abundant and most important organic carbonyl compound in the atmosphere. The sources of formaldehyde are the oxidation of methane, isoprene, acetone, and other volatile organic compounds (VOCs); fossil fuel combustion; and biomass burning. The dominant loss mechanism for formaldehyde is photolysis which occurs via two pathways: (R1) HCHO + hv → HCO + H (R2) HCHO + hv → H2 + CO The first pathway (R1) is referred to as the radical channel, while the second pathway (R2) is referred to as the molecular channel. The products of both pathways play a significant role in atmospheric chemistry. The CO that is produced in the molecular channel undergoes further oxidation to produce CO2. Under atmospheric conditions, the H atom and formyl radical that are produced in the radical channel undergo rapid reactions with O2 to produce the hydroperoxyl radical (HO2) via (R3) and (R4). (R3) HCO + O2 → HO2 + CO (R4) H + O2 → HO2 Thus, for every photon absorbed, the photolysis of formaldehyde can contribute one CO2 molecule to the global greenhouse budget or two HO2 radicals to the tropospheric HOx (OH + HO2) cycle. The HO2 radicals produced during formaldehyde photolysis have also been implicated in the formation of photochemical smog. The HO2 radicals act as radical chain carriers and convert NO to NO2, which ultimately results in the catalytic production of O3. Constraining the yield of HO2 produced via HCHO photolysis is essential for improving tropospheric chemistry models. In this study, both the absorption cross section and the quantum yield of the radical channel (R1) were measured at high resolution over the tropospherically relevant wavelength range 304-330 nm. For the cross section measurements a narrow linewidth Nd:YAG pumped dye laser was used with a multi-pass cell. Partial pressures of HCHO were kept below 0.3 torr. Simultaneous measurement of OH LIF in a flame allowed absolute calibration of the wavelength scale. Pressure

  12. MRI at 3 Tesla detects no evidence for ischemic brain damage in intensively treated patients with homozygous familial hypercholesterolemia

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Stephan A.; O' Regan, Declan P.; Fitzpatrick, Julie; Hajnal, Joseph V. [Hammersmith Hospital Campus, Imaging Sciences Department, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, London (United Kingdom); Neuwirth, Clare; Potter, Elizabeth; Tosi, Isabella; Naoumova, Rossi P. [MRC Clinical Sciences Centre, Clinical Research Facility, London (United Kingdom); Hammersmith Hospital, Lipid Clinic, London (United Kingdom)

    2007-11-15

    Homozygous familial hypercholesterolemia (FH) is considered a model disease for excessive plasma cholesterol levels. Patients with untreated homozygous FH have a markedly increased risk for premature atherosclerosis. The frequency and extent of ischemic brain damage detectable by high-field magnetic resonance imaging (MRI) after long-term intensive treatment are unknown. In a case control study, five patients with homozygous FH (one male and four females; mean age: 23.6 {+-} 9.2, range: 12-36 years; mean pre-treatment serum total cholesterol level: 26.9 {+-} 3.24 mmol/L; all patients with documented atherosclerotic plaques in the carotid arteries) and five age- and sex-matched healthy controls were studied. All patients had been on maximal lipid-lowering medication since early childhood, and four of them were also on treatment with low-density lipoprotein (LDL) apheresis at bi-weekly intervals. Brain MRI was performed at 3 Tesla field strength with fluid-attenuated T2-weighted inversion recovery and T1-weighted spin-echo MR pulse sequences and subsequently evaluated by two independent readers. The maximal lipid-lowering treatment reduced the total serum cholesterol by more than 50% in the patients, but their serum concentrations were still 3.6-fold higher than those found in the controls (11.9 {+-} 4.2 vs. 4.5 {+-} 0.5 mmol/L; p < 0.0047). No brain abnormality was observed in any of the patients with homozygous FH. Homozygous FH patients on intensive cholesterol-lowering therapy have no evidence of ischemic brain damage at 3 Tesla MRI despite the remaining high cholesterol levels. (orig.)

  13. Cortical microinfarcts detected in vivo on 3 Tesla MRI: clinical and radiological correlates.

    Science.gov (United States)

    van Dalen, Jan Willem; Scuric, Eva E M; van Veluw, Susanne J; Caan, Matthan W A; Nederveen, Aart J; Biessels, Geert Jan; van Gool, Willem A; Richard, Edo

    2015-01-01

    Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. We evaluated CMIs on 3 Tesla MRI in a population-based cohort of 194 nondemented older people (72-80 years) with systolic hypertension. Using a case-control design, participants with and without CMIs were compared on age, sex, cardiovascular risk factors, and white matter hyperintensity volume. We identified 23 CMIs in 12 participants (6%). CMIs were associated with older age, higher diastolic blood pressure, and a history of recent stroke. There was a trend for a higher white matter hyperintensity volume in participants with CMIs. We found an association of CMIs with clinical parameters, including age and cardiovascular risk factors. Although the prevalence of CMIs is relatively low, our results suggest that the study of CMIs in larger clinical studies is possible using 3 Tesla MRI. This opens the possibility of large-scale prospective investigation of the clinical relevance of CMIs in older people. © 2014 American Heart Association, Inc.

  14. High resolution digital delay timer

    Science.gov (United States)

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  15. Value of 3 Tesla diffusion-weighted magnetic resonance imaging for assessing liver fibrosis.

    Science.gov (United States)

    Papalavrentios, Lavrentios; Sinakos, Emmanouil; Chourmouzi, Danai; Hytiroglou, Prodromos; Drevelegas, Konstantinos; Constantinides, Manos; Drevelegas, Antonios; Talwalkar, Jayant; Akriviadis, Evangelos

    2015-01-01

    Limited data are available regarding the role of magnetic resonance imaging (MRI), particularly the new generation 3 Tesla technology, and especially diffusion-weighted imaging (DWI) in predicting liver fibrosis. The aim of our pilot study was to assess the clinical performance of the apparent diffusion coefficient (ADC) of liver parenchyma for the assessment of liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). 18 patients with biopsy-proven NAFLD underwent DWI with 3 Tesla MRI. DWI was performed with single-shot echo-planar technique at b values of 0-500 and 0-1000 s/mm(2). ADC was measured in four locations in the liver and the mean ADC value was used for analysis. Staging of fibrosis was performed according to the METAVIR system. The median age of patients was 52 years (range 23-73). The distribution of patients in different fibrosis stages was: 0 (n=1), 1 (n=7), 2 (n=1), 3 (n=5), 4 (n=4). Fibrosis stage was poorly associated with ADC at b value of 0-500 s/mm(2) (r= -0.30, P=0.27). However it was significantly associated with ADC at b value of 0-1000 s/mm(2) (r= -0.57, P=0.01). For this b value (0-1000 s/mm(2)) the area under receiver-operating characteristic curve was 0.93 for fibrosis stage ≥3 and the optimal ADC cut-off value was 1.16 ×10(-3) mm(2)/s. 3 Tesla DWI can possibly predict the presence of advanced fibrosis in patients with NAFLD.

  16. Multisequence-imaging protocols to detect cortical lesions of patients with multiple sclerosis: observations from a post-mortem 3 Tesla imaging study.

    Science.gov (United States)

    Bagnato, Francesca; Yao, Bing; Cantor, Fredric; Merkle, Hellmut; Condon, Ellen; Montequin, Marcela; Moore, Sandra; Quezado, Martha; Tkaczyk, Deborah; McFarland, Henry

    2009-07-15

    Neocortical lesions (NLs) are an important component of multiple sclerosis (MS) pathology and may account for part of the physical and cognitive disability. Visualizing NLs of patients with MS using magnetic resonance imaging (MRI) poses several significant challenges. We optimized the inversion time (TI) of T(1)-based magnetization-prepared rapid acquisition gradient-echo (MPRAGE) images by suppressing the signal of the lesions and enhancing their appearance as hypointensities, on the basis of the derived quantitative T(1) measurements. The latter were achieved by the means of 2D inversion recovery fast spin echo (IR-FSE), repeated using different inversion times (TI). Comparisons of detection of NLs by MPRAGE and dual echo T(2) weighted (T(2)W) and proton density (PD) W. Four coronal brain slices from a deceased MS patient and two coronal brain slices from two formerly healthy donors were imaged using a 3 Tesla magnet (3 T) equipped with a multi-channel coil. Based upon the averaged T1 values computed from the MS specimen as well as visual inspection, an optimal TI of 380 ms was selected for the MPRAGE image. No NLs were seen in the specimens of the two healthy donors. Of the 40 total NLs observed, 8 (20%) were visible in all three sequences employed. Three (7.5%) NLs were visible only in the PDW image and 5 (12.5%) were seen only in the T(2)W image. Four NLs (10%) had clearly unique conspicuity in the MPRAGE image. Of those, 3 were retrospectively scored in the PDW image (1 NL) or in the T2W image (2 NLs). We conclude that for the detection of MS-related NLs, high-resolution T(1)-based MPRAGE and T(2)-W images offer complementary information and the combination of the two image sequences is crucial for increasing the sensitivity of detecting MS-induced NLs.

  17. Incidental optochiasmatic cavernoma: Case report of an unusual finding on 3 Tesla MRI.

    Science.gov (United States)

    Trentadue, Mirko; Pozzi Mucelli, Roberto; Piovan, Enrico; Pizzini, Francesca Benedetta

    2016-08-01

    Cavernoma is a vascular hamartoma, which represents 10-20% of all central nervous system vascular malformations. The majority (80%) of them are supratentorial, while involvement of the cranial nerves and the optic pathways is extremely rare. The main clinical presentation of optochiasmatic cavernomas consists of chiasmatic apoplexy, which is a neurosurgical emergency. Here, we report a case in which the finding was incidentally detected in a 49-year-old man. We describe the imaging characteristics of the lesion in such a rare location, highlighting the role of magnetic resonance imaging (MRI) (specifically 3 Tesla) in the management of asymptomatic patients.

  18. 3 Tesla magnetic resonance imaging obtained 4 hours after intravenous gadolinium injection in patients with sudden deafness.

    Science.gov (United States)

    Tagaya, Mitsuhiko; Teranishi, Masaaki; Naganawa, Shinji; Iwata, Tomoyuki; Yoshida, Tadao; Otake, Hironao; Nakata, Seiichi; Sone, Michihiko; Nakashima, Tsutomu

    2010-06-01

    3 Tesla (3T) magnetic resonance imaging (MRI) performed 4 h after intravenous gadolinium (Gd) injection provides sufficient anatomic resolution of the inner ear fluid spaces in sudden deafness. The signal intensity ratio (SIR) between the cochlea and cerebellum may be a good indicator of disruption of the blood-labyrinthine barrier. We evaluated the inner ear 4 h after intravenous Gd injection to determine whether 3T MRI enables the acquisition of images of the affected inner ear in sudden deafness. Ten patients underwent 3T MRI scanning 4 h after intravenous Gd injection. Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) MRI was performed. The SIR varied from 0.45 to 2.17 in 11 affected ears and from 0.43 to 1.48 in 9 unaffected ears. The difference of contrast (affected ear vs unaffected ear) could be detected in five of the nine patients with unilateral sudden deafness. The Gd distribution was recognized in the vestibule of 10 affected ears and in the cochlea of 5 affected ears, in which no significant hydrops was observed. In the remaining vestibules and cochleas of affected ears, the Gd enhancement was too faint to evaluate the endolymphatic hydrops.

  19. Inter-observer agreement and diagnostic accuracy of myocardial perfusion reserve quantification by cardiovascular magnetic resonance at 3 Tesla in comparison to quantitative coronary angiography.

    Science.gov (United States)

    Ikuye, Katharina; Buckert, Dominik; Schaaf, Lisa; Walcher, Thomas; Rottbauer, Wolfgang; Bernhardt, Peter

    2013-03-27

    Quantification of cardiovascular magnetic resonance (CMR) myocardial perfusion reserve (MPR) at 1.5 Tesla has been shown to correlate to invasive evaluation of coronary artery disease (CAD) and to yield good inter-observer agreement. However, little is known about quantitative adenosine-perfusion CMR at 3 Tesla and no data about inter-observer agreement is available. Aim of our study was to evaluate inter-observer agreement and to assess the diagnostic accuracy in comparison to quantitative coronary angiography (QCA). Fifty-three patients referred for coronary x-ray angiography were previously examined in a 3 Tesla whole-body scanner. Adenosine and rest perfusion CMR were acquired for the quantification of MPR in all segments. Two blinded and independent readers analyzed all images. QCA was performed in case of coronary stenosis. QCA data was used to assess diagnostic accuracy of the MPR measurements. Inter-observer agreement was high for all myocardial perfusion territories (ρ = 0.92 for LAD, ρ = 0.93 for CX and RCA perfused segments). Compared to QCA receiver-operating characteristics yielded an area under the curve of 0.78 and 0.73 for RCA, 0.66 and 0.69 for LAD, and 0.52 and 0.53 for LCX perfused territories. Inter-observer agreement of MPR quantification at 3 Tesla CMR is very high for all myocardial segments. Diagnostic accuracy in comparison to QCA yields good values for the RCA and LAD perfused territories, but moderate values for the posterior LCX perfused myocardial segments.

  20. Intraoperative 3-tesla MRI in the management of paediatric cranial tumours - initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Avula, Shivaram; Garlick, Deborah; Abernethy, Laurence J. [Alder Hey Children' s NHS Foundation Trust, Department of Radiology, Liverpool (United Kingdom); Mallucci, Connor L. [Alder Hey Children' s Hospital, Department of Neurosurgery, Liverpool (United Kingdom); Pizer, Barry [Alder Hey Children' s Hospital, Department of Oncology, Liverpool (United Kingdom); Crooks, Daniel [Walton Centre for Neurology and Neurosurgery, Department of Pathology, Liverpool (United Kingdom)

    2012-02-15

    Intraoperative MRI (ioMRI) has been gaining recognition because of its value in the neurosurgical management of cranial tumours. There is limited documentation of its value in children. To review the initial experience of a paediatric 3-Tesla ioMRI unit in the management of cranial tumours. Thirty-eight children underwent ioMRI during 40 cranial tumour resections using a 3-Tesla MR scanner co-located with the neurosurgical operating theatre. IoMRI was performed to assess the extent of tumour resection and/or to update neuronavigation. The intraoperative and follow-up scans, and the clinical records were reviewed. In 27/40 operations, complete resection was intended. IoMRI confirmed complete resection in 15/27 (56%). As a consequence, surgical resection was extended in 5/27 (19%). In 6/27 (22%), ioMRI was equivocal for residual tumour. In 13/40 (33%) operations, the surgical aim was to partially resect the tumour. In 7 of the 13 (54%), surgical resection was extended following ioMRI. In our initial experience, ioMRI has increased the rate of complete resection, with intraoperative surgical strategy being modified in 30% of procedures. Collaborative analysis of ioMRI by the radiologist and neurosurgeon is vital to avoid errors in interpretation. (orig.)

  1. Evaluation of MRI artifacts at 3 Tesla for 38 commonly used cosmetics.

    Science.gov (United States)

    Escher, Kirin; Shellock, Frank G

    2013-06-01

    To evaluate MRI artifacts at 3-Tesla for 38 commonly used cosmetics. Thirty-eight cosmetics (16, nail polishes; 5, eyeliners; 3, mascaras; 10, eye shadows; 1, lip gloss; 1, body lotion; 1, body glitter, and 1, hair loss concealer) underwent evaluation for MRI artifacts at 3-Tesla. The cosmetics were applied a copper-sulfate-filled, phantom and initially assessed using a "screening" gradient echo (GRE) pulse sequence. Of the 38 different cosmetics, 14 (37%) exhibited artifacts. For these 14 cosmetics, additional characterization of artifacts was performed using a GRE pulse sequence. A qualitative scale was applied to characterize the artifact size. Artifacts were observed, as follows: 2, nail polishes; 5, eyeliners; 3, mascaras; 3, eye shadows; 1, hair loss concealer. Artifact size ranged from small (eye shadow) to very large (hair loss concealer) and tended to be associated with the presence of iron oxide or other metal-based ingredient. Commonly used cosmetics caused artifacts that may create issues if the area of interest is the same as where the cosmetic was applied or if its presence was unknown, thus, potentially causing it to be construed as pathology. Therefore, these findings have important implications for patients referred for MRI examinations. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Chemical exchange saturation transfer MR imaging of Parkinson's disease at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chunmei; Peng, Shuai; Wang, Rui; Chen, Min [Beijing Hospital, Department of Radiology, Beijing (China); Chen, Haibo; Su, Wen [Beijing Hospital, Department of Neurology, Beijing (China); Zhao, Xuna [Peking University, Center for MRI Research and Beijing City Key Lab for Medical Physics and Engineering, Beijing (China); Zhou, Jinyuan [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States)

    2014-10-15

    To demonstrate the feasibility of using chemical exchange saturation transfer (CEST) imaging to detect Parkinson's disease (PD) in patients at 3 Tesla. Twenty-seven PD patients (17 men and 10 women; age range, 54-77 years) and 22 age-matched normal controls (13 men and 9 women; age range, 55-73 years) were examined on a 3-Tesla MRI system. Magnetization transfer spectra with 31 different frequency offsets (-6 to 6 ppm) were acquired at two transverse slices of the head, including the basal ganglia and midbrain. One-way analysis of variance tests was used to compare the differences in CEST imaging signals between PD patients and normal controls. Total CEST signal between the offsets of 0 and 4 ppm in the substantia nigra was significantly lower in PD patients than in normal controls (P = 0.006), which could be associated with the loss of dopaminergic neurons. Protein-based CEST imaging signals at the offset of 3.5 ppm in the globus pallidus, putamen and caudate were significantly increased in PD patients, compared to normal controls (P < 0.001, P = 0.003, P < 0.001, respectively). CEST imaging signals could potentially serve as imaging biomarkers to aid in the non-invasive molecular diagnosis of PD. (orig.)

  3. High Resolution Orientation Imaging Microscopy

    Science.gov (United States)

    2012-05-02

    carbon distribution as it relates to the presence of Bainite phase (with small tetragonality) interspersed among the cubic ferrite. An example of the...preferentially segregate. The view offered by these high resolution methods differs from what has been considered before: grains thought to be Bainite

  4. High-Resolution Instrumentation Radar.

    Science.gov (United States)

    1986-09-30

    30 September 1986 Los Angeles Air Force Station 13. NUMBER OF PAGES Los Angeles, Calif. 90009-2960 36 74. MONITORING AGENCY NAME & ADDRESS(If...TREE PLMUT ",-20 -CUTLIASS DumpER SED AN... TREE TRUNK, -0 - MERC BUMPER f - 40 H!-I -50 iI Fig. 7. High-Resolution Instrumentation Radar View of

  5. Requirements on high resolution detectors

    Energy Technology Data Exchange (ETDEWEB)

    Koch, A. [European Synchrotron Radiation Facility, Grenoble (France)

    1997-02-01

    For a number of microtomography applications X-ray detectors with a spatial resolution of 1 {mu}m are required. This high spatial resolution will influence and degrade other parameters of secondary importance like detective quantum efficiency (DQE), dynamic range, linearity and frame rate. This note summarizes the most important arguments, for and against those detector systems which could be considered. This article discusses the mutual dependencies between the various figures which characterize a detector, and tries to give some ideas on how to proceed in order to improve present technology.

  6. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  7. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  8. HRSC: High resolution stereo camera

    Science.gov (United States)

    Neukum, G.; Jaumann, R.; Basilevsky, A.T.; Dumke, A.; Van Gasselt, S.; Giese, B.; Hauber, E.; Head, J. W.; Heipke, C.; Hoekzema, N.; Hoffmann, H.; Greeley, R.; Gwinner, K.; Kirk, R.; Markiewicz, W.; McCord, T.B.; Michael, G.; Muller, Jan-Peter; Murray, J.B.; Oberst, J.; Pinet, P.; Pischel, R.; Roatsch, T.; Scholten, F.; Willner, K.

    2009-01-01

    The High Resolution Stereo Camera (HRSC) on Mars Express has delivered a wealth of image data, amounting to over 2.5 TB from the start of the mapping phase in January 2004 to September 2008. In that time, more than a third of Mars was covered at a resolution of 10-20 m/pixel in stereo and colour. After five years in orbit, HRSC is still in excellent shape, and it could continue to operate for many more years. HRSC has proven its ability to close the gap between the low-resolution Viking image data and the high-resolution Mars Orbiter Camera images, leading to a global picture of the geological evolution of Mars that is now much clearer than ever before. Derived highest-resolution terrain model data have closed major gaps and provided an unprecedented insight into the shape of the surface, which is paramount not only for surface analysis and geological interpretation, but also for combination with and analysis of data from other instruments, as well as in planning for future missions. This chapter presents the scientific output from data analysis and highlevel data processing, complemented by a summary of how the experiment is conducted by the HRSC team members working in geoscience, atmospheric science, photogrammetry and spectrophotometry. Many of these contributions have been or will be published in peer-reviewed journals and special issues. They form a cross-section of the scientific output, either by summarising the new geoscientific picture of Mars provided by HRSC or by detailing some of the topics of data analysis concerning photogrammetry, cartography and spectral data analysis.

  9. Clinical functional MRI of sensorimotor cortex using passive motor and sensory stimulation at 3 Tesla.

    Science.gov (United States)

    Blatow, Maria; Reinhardt, Julia; Riffel, Katharina; Nennig, Ernst; Wengenroth, Martina; Stippich, Christoph

    2011-08-01

    To establish a passive motor paradigm for clinical functional MRI (fMRI) that could be beneficial for patients with motor or attention deficits who are not able to perform active motor tasks. A novel standardized sensorimotor fMRI protocol was applied in 16 healthy volunteers at 3 Tesla (T) using active and passive motor tasks as well as sensory stimulation of hands and feet. Data analysis was carried out individually using a dynamic thresholding routine. Active motor tasks yielded time efficient and robust blood-oxygen-level-dependent (BOLD) signals in primary motor cortex. Noteworthy, it was possible to achieve equal activation levels within identical anatomical localization for passive and active motor tasks with these paradigms. Patients unable to perform active movements can benefit from paradigms with passive motor and sensory stimulation. Therefore, we recommend these paradigms for functional somatotopic mapping of the central region at 3T in clinical routine. Copyright © 2011 Wiley-Liss, Inc.

  10. A free-breathing non-contrast-enhanced pulmonary magnetic resonance angiography at 3 Tesla

    Institute of Scientific and Technical Information of China (English)

    YANG Jian; WANG Wei; WANG Ya-rong; NIU Gang; JIN Chen-wang; WU Ed Xuekui

    2009-01-01

    Background The breathhold contrast-enhanced three-dimensional magnetic resonance angiography (MRA) using T1-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla.Methods The time-of-flight protocol was based on a two-dimensional T1-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects.Results Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of ~300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20°-30°. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel.Conclusions The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.

  11. Section on High Resolution Optical Imaging (HROI)

    Data.gov (United States)

    Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

  12. Comparison of pelvic phased-array versus endorectal coil magnetic resonance imaging at 3 Tesla for local staging of prostate cancer.

    Science.gov (United States)

    Kim, Bum Soo; Kim, Tae-Hwan; Kwon, Tae Gyun; Yoo, Eun Sang

    2012-05-01

    Several studies have demonstrated the superiority of endorectal coil magnetic resonance imaging (MRI) over pelvic phased-array coil MRI at 1.5 Tesla for local staging of prostate cancer. However, few have studied which evaluation is more accurate at 3 Tesla MRI. In this study, we compared the accuracy of local staging of prostate cancer using pelvic phased-array coil or endorectal coil MRI at 3 Tesla. Between January 2005 and May 2010, 151 patients underwent radical prostatectomy. All patients were evaluated with either pelvic phased-array coil or endorectal coil prostate MRI prior to surgery (63 endorectal coils and 88 pelvic phased-array coils). Tumor stage based on MRI was compared with pathologic stage. We calculated the specificity, sensitivity and accuracy of each group in the evaluation of extracapsular extension and seminal vesicle invasion. Both endorectal coil and pelvic phased-array coil MRI achieved high specificity, low sensitivity and moderate accuracy for the detection of extracapsular extension and seminal vesicle invasion. There were statistically no differences in specificity, sensitivity and accuracy between the two groups. Overall staging accuracy, sensitivity and specificity were not significantly different between endorectal coil and pelvic phased-array coil MRI.

  13. High-resolution intravital microscopy.

    Directory of Open Access Journals (Sweden)

    Volker Andresen

    Full Text Available Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy--the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and

  14. High-resolution image analysis.

    Science.gov (United States)

    Preston, K

    1986-01-01

    In many departments of cytology, cytogenetics, hematology, and pathology, research projects using high-resolution computerized microscopy are now being mounted for computation of morphometric measurements on various structural components, as well as for determination of cellular DNA content. The majority of these measurements are made in a partially automated, computer-assisted mode, wherein there is strong interaction between the user and the computerized microscope. At the same time, full automation has been accomplished for both sample preparation and sample examination for clinical determination of the white blood cell differential count. At the time of writing, approximately 1,000 robot differential counting microscopes are in the field, analyzing images of human white blood cells, red blood cells, and platelets at the overall rate of about 100,000 slides per day. This mammoth through-put represents a major accomplishment in the application of machine vision to automated microscopy for hematology. In other areas of automated high-resolution microscopy, such as cytology and cytogenetics, no commercial instruments are available (although a few metaphase-finding machines are available and other new machines have been announced during the past year). This is a disappointing product, considering the nearly half century of research effort in these areas. This paper provides examples of the state of the art in automation of cell analysis for blood smears, cervical smears, and chromosome preparations. Also treated are new developments in multi-resolution automated microscopy, where images are now being generated and analyzed by a single machine over a range of 64:1 magnification and from 10,000 X 20,000 to 500 X 500 in total picture elements (pixels). Examples of images of human lymph node and liver tissue are presented. Semi-automated systems are not treated, although there is mention of recent research in the automation of tissue analysis.

  15. High-Resolution Mass Spectrometers

    Science.gov (United States)

    Marshall, Alan G.; Hendrickson, Christopher L.

    2008-07-01

    Over the past decade, mass spectrometry has been revolutionized by access to instruments of increasingly high mass-resolving power. For small molecules up to ˜400 Da (e.g., drugs, metabolites, and various natural organic mixtures ranging from foods to petroleum), it is possible to determine elemental compositions (CcHhNnOoSsPp…) of thousands of chemical components simultaneously from accurate mass measurements (the same can be done up to 1000 Da if additional information is included). At higher mass, it becomes possible to identify proteins (including posttranslational modifications) from proteolytic peptides, as well as lipids, glycoconjugates, and other biological components. At even higher mass (˜100,000 Da or higher), it is possible to characterize posttranslational modifications of intact proteins and to map the binding surfaces of large biomolecule complexes. Here we review the principles and techniques of the highest-resolution analytical mass spectrometers (time-of-flight and Fourier transform ion cyclotron resonance and orbitrap mass analyzers) and describe some representative high-resolution applications.

  16. Ultra-high resolution AMOLED

    Science.gov (United States)

    Wacyk, Ihor; Prache, Olivier; Ghosh, Amal

    2011-06-01

    AMOLED microdisplays continue to show improvement in resolution and optical performance, enhancing their appeal for a broad range of near-eye applications such as night vision, simulation and training, situational awareness, augmented reality, medical imaging, and mobile video entertainment and gaming. eMagin's latest development of an HDTV+ resolution technology integrates an OLED pixel of 3.2 × 9.6 microns in size on a 0.18 micron CMOS backplane to deliver significant new functionality as well as the capability to implement a 1920×1200 microdisplay in a 0.86" diagonal area. In addition to the conventional matrix addressing circuitry, the HDTV+ display includes a very lowpower, low-voltage-differential-signaling (LVDS) serialized interface to minimize cable and connector size as well as electromagnetic emissions (EMI), an on-chip set of look-up-tables for digital gamma correction, and a novel pulsewidth- modulation (PWM) scheme that together with the standard analog control provides a total dimming range of 0.05cd/m2 to 2000cd/m2 in the monochrome version. The PWM function also enables an impulse drive mode of operation that significantly reduces motion artifacts in high speed scene changes. An internal 10-bit DAC ensures that a full 256 gamma-corrected gray levels are available across the entire dimming range, resulting in a measured dynamic range exceeding 20-bits. This device has been successfully tested for operation at frame rates ranging from 30Hz up to 85Hz. This paper describes the operational features and detailed optical and electrical test results for the new AMOLED WUXGA resolution microdisplay.

  17. High-resolution slug testing.

    Science.gov (United States)

    Zemansky, G M; McElwee, C D

    2005-01-01

    The hydraulic conductivity (K) variation has important ramifications for ground water flow and the transport of contaminants in ground water. The delineation of the nature of that variation can be critical to complete characterization of a site and the planning of effective and efficient remedial measures. Site-specific features (such as high-conductivity zones) need to be quantified. Our alluvial field site in the Kansas River valley exhibits spatial variability, very high conductivities, and nonlinear behavior for slug tests in the sand and gravel aquifer. High-resolution, multilevel slug tests have been performed in a number of wells that are fully screened. A general nonlinear model based on the Navier-Stokes equation, nonlinear frictional loss, non-Darcian flow, acceleration effects, radius changes in the wellbore, and a Hvorslev model for the aquifer has been used to analyze the data, employing an automated processing system that runs within the Excel spreadsheet program. It is concluded that slug tests can provide the necessary data to identify the nature of both horizontal and vertical K variation in an aquifer and that improved delineation or higher resolution of K structure is possible with shorter test intervals. The gradation into zones of higher conductivity is sharper than seen previously, and the maximum conductivity observed is greater than previously measured. However, data from this project indicate that well development, the presence of fines, and the antecedent history of the well are important interrelated factors in regard to slug-test response and can prevent obtaining consistent results in some cases.

  18. Early detection of pulp necrosis and dental vitality after traumatic dental injuries in children and adolescents by 3-Tesla magnetic resonance imaging.

    Science.gov (United States)

    Assaf, Alexandre T; Zrnc, Tomislav A; Remus, Chressen C; Khokale, Arun; Habermann, Christian R; Schulze, Dirk; Fiehler, Jens; Heiland, Max; Sedlacik, Jan; Friedrich, Reinhard E

    2015-09-01

    More than 50% of all children suffer a traumatic dental injury (TDI) during childhood. In many cases, dentists apply root canal treatment (RCT), which is performed on an average of 7-10 days after replantation. Our aim was to evaluate whether RCT is necessary in many cases, and whether revitalization of affected teeth is possible and measurable by visualization using 3T magnetic resonance imaging (MRI). Seven healthy children with TDI were treated by repositioning of the affected teeth and reduction of alveolar process fractures followed by splinting. Two weeks after initial treatment, splints were removed. After 6 weeks, all children received 3-Tesla (3T), three-dimensional, high-resolution MRI with a 20-channel standard head and neck coil. The mean age of the children (male/female = 5:2) was 10.8 years (range, 8-17 years). In addition, all children received conventional dental examination for tooth vitality and dental sensitivity to cold and tenderness on percussion. 3T MRI provided excellent images that allowed fine discrimination between dental pulp and adjacent tooth. Using four in-house optimized, non-contrast-enhanced sequences, including panoramic reconstruction, the assessment and analysis of the dental pulp was sufficiently feasible. We could demonstrate reperfusion and thus vitality of the affected teeth in 11 sites. In one child, MRI was able to detect nonreperfusion after TDI of the affected tooth. MRI results were confirmed by clinical examination in all cases. As a consequence of this expectant management and proof of reperfusion and tooth vitality by 3T MRI, only one child had to be treated by RCT. 3T MRI is a very promising tool for visualization and detection in the field of dental and oromaxillofacial diseases. By using new 3T MRI sequences in children with TDI, we could demonstrate that RCT are not necessary in every case, and thus could prevent unnecessary treatment of children in the future. Larger studies should follow to confirm the

  19. High-resolution land topography

    Science.gov (United States)

    Massonnet, Didier; Elachi, Charles

    2006-11-01

    After a description of the background, methods of production and some scientific uses of high-resolution land topography, we present the current status and the prospect of radar interferometry, regarded as one of the best techniques for obtaining the most global and the most accurate topographic maps. After introducing briefly the theoretical aspects of radar interferometry - principles, limits of operation and various capabilities -, we will focus on the topographic applications that resulted in an almost global topographic map of the earth: the SRTM map. After introducing the Interferometric Cartwheel system, we will build on its expected performances to discuss the scientific prospects of refining a global topographic map to sub-metric accuracy. We also show how other fields of sciences such as hydrology may benefit from the products generated by interferometric radar systems. To cite this article: D. Massonnet, C. Elachi, C. R. Geoscience 338 (2006).

  20. Double-bundle depiction of the anterior cruciate ligament at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Adriaensen, M.E.A.P.M. [Atrium Medical Center Parkstad, Department of Radiology, Heerlen (Netherlands); Hogan, B. [Sports Surgery Clinic, Department of Radiology, Dublin (Ireland); Al-Bulushi, H.I.J. [Armed Forces Hospital, Department of Radiology, Muscat (Oman); Kavanagh, E.C. [Mater Misericordiae Hospital, Department of Radiology, Dublin (Ireland)

    2012-07-15

    Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice. In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used. Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%). The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee. (orig.)

  1. The "mirror-neuron system" in MS: A 3 tesla fMRI study.

    Science.gov (United States)

    Rocca, M A; Tortorella, P; Ceccarelli, A; Falini, A; Tango, D; Scotti, G; Comi, G; Filippi, M

    2008-01-22

    The mirror neuron system (MNS) is an observation-execution matching system activated, in humans, during action observation, motor learning, and imitation of action. We used functional MRI (fMRI) to investigate the properties of the MNS in patients with multiple sclerosis (MS). Using a 3 tesla scanner, we acquired fMRI in 16 right-handed patients with relapsing-remitting MS and 14 controls. Two motor tasks were studied. The first consisted of repetitive flexion-extension of the last four fingers of the right hand (simple task) alternated to epochs of rest; the second (MNS task) consisted of observation of a movie showing the hand of another subject while performing the same task. During the simple task, compared to controls, patients with MS had more significant activations of the contralateral primary sensorimotor cortex and supplementary motor area. During the MNS task, both groups showed the activation of several visual areas, the infraparietal sulcus, and the inferior frontal gyrus (IFG), bilaterally. The IFG and the visual areas were significantly more active in patients than controls. The between-group interaction analysis showed that in patients with MS, part of the regions of the MNS were more active also during the simple task. This study suggests increased activation of the mirror neuron system in patients with multiple sclerosis (MS) with a normal level of function and widespread CNS damage. The potentialities of this system in facilitating clinical recovery in patients with MS and other neurologic conditions should be investigated.

  2. Horizontal nystagmus and multiple sclerosis using 3-Tesla magnetic resonance imaging.

    Science.gov (United States)

    Iyer, P M; Fagan, A J; Meaney, J F; Colgan, N C; Meredith, S D; Driscoll, D O; Curran, K M; Bradley, D; Redmond, J

    2016-11-01

    Nystagmus in patients with multiple sclerosis (MS) is generally attributed to brainstem disease. Lesions in other regions may result in nystagmus. The identification of these other sites is enhanced by using 3-Tesla magnetic resonance imaging (3TMRI) due to increased signal-to-noise ratio. We sought to evaluate the distribution of structural lesions and disruption of tracts in patients with horizontal nystagmus secondary to MS using 3TMRI. Twenty-four patients (20 women, 4 men; age range 26-55 years) with horizontal nystagmus secondary to MS underwent 3TMRI brain scans; and 18 patients had diffusion tensor imaging (DTI) for tractography. Nystagmus was bidirectional in 11, right-sided in 6 and left-sided in 7. We identified 194 lesions in 20 regions within the neural integrator circuit in 24 patients; 140 were within the cortex and 54 were within the brainstem. Only two patients had no lesions in the cortex, and 9 had no lesions in the brainstem. There was no relationship between side of lesion and direction of nystagmus. Thirteen of 18 (72 %) had tract disruption with fractional anisotropy (FA) values below 0.2. FA was significantly lower in bidirectional compared to unidirectional nystagmus (p = 0.006). In MS patients with horizontal nystagmus, lesions in all cortical eye fields and their descending connections were evident. Technical improvements in tractography may help identify the specific site(s) resulting in nystagmus in MS.

  3. 3 tesla magnetic resonance imaging of the occipitoatlantoaxial region in the normal horse.

    Science.gov (United States)

    Gutiérrez-Crespo, Beatriz; Kircher, Patrick R; Carrera, Ines

    2014-01-01

    The aim of this study was to describe the appearance of the ligamentous structures of the occipitoatlantoaxial (OAA) region in the normal horse by 3 tesla (3T) magnetic resonance imaging (MRI). The MRI images of the longitudinal odontoid ligament, tectorial membrane, dorsal and ventral atlantoaxial ligaments, dorsal atlantooccipital membrane with its reinforcing ligaments, and the lateral atlantooccipital ligaments of 10 horse cadavers were evaluated. All ligaments and membranes were identified in all planes, except for the lateral atlantooccipital ligament in the sagittal plane due to its cranioventrolateral course. All were iso to mildly hypointense to musculature of the neck in T1W with the exception of the tectorial membrane that was moderately hypointense; moderately hypointense in PD-SPIR, and markedly hypointense (isointense to cortical bone) in T2W. The PD-SPIR was the best sequence to identify all ligaments and membranes from their cranial and caudal attachments. The longitudinal odontoid ligament, ventral atlantoaxial ligament, and reinforcing bands of the dorsal atlantooccipital membrane presented a characteristic striped heterogeneous signal behavior thought to be due to fibrocartilaginous content. The remaining ligaments and membranes showed homogeneous signal intensity. Special anatomical features in this species such as the fan-shaped longitudinal odontoid ligament, absence of the transverse ligament and presence of the ventral atlantoaxial ligament were documented. Ligamentous structures that stabilize the equine OAA region were described with MRI in this study and these findings could serve as an anatomic reference for those cases where instability of this region is suspected.

  4. Is the type and extent of hippocampal sclerosis measurable on high-resolution MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Urbach, H; Schwarzwald, R [Medical Center University of Freiburg, Dept. of Neuroradiology, Freiburg (Germany); Huppertz, H.J. [Swiss Epilepsy Center, Zurich (Switzerland); Becker, A.J. [Medical Center University of Bonn, Department of Neuropathology, Bonn (Germany); Wagner, J. [Medical Center University of Bonn, Department of Epileptology, Bonn (Germany); Bahri, M. Delsous; Tschampa, H.J. [Medical Center University of Bonn, Department of Radiology/Neuroradiology, Bonn (Germany)

    2014-09-15

    The purpose of this study is to relate hippocampal volume and FLAIR signal intensity to Wyler grading of hippocampal sclerosis (HS). Of 100 consecutive patients with temporal lobe epilepsy and HS as histopathological diagnosis, 32 had high-resolution 3 Tesla MRI and anatomically well-preserved hippocampi following amygdalo-hippocampectomy. Hippocampal volume on 3D T1-weighted gradient echo and signal intensity on coronal FLAIR sequences were determined using FreeSurfer and SPM tools and related to Wyler grading. Seizure outcome was determined after 1 year. Histopathology showed four Wyler II, 19 Wyler III, and 9 Wyler IV HS. Hippocampal volumes were 3.08 ml for Wyler II (Wyler II/contralateral side: p > 0.05), 2.19 ml for Wyler III (p < 0.01), 2.62 ml for Wyler IV (p = 0.01), and 3.08 ml for the contralateral side. Normalized FLAIR signals were 1,354 (p = 0.0004), 1,408 (p < 0.0001), 1,371 (p < 0.04), and 1,296, respectively. Wyler II hippocampi were visually normal. Two of four (50 %) Wyler II, 16/19 (84 %) Wyler III, and 6/9 (66 %) Wyler IV patients achieved Engel I outcome. Combined volumetry and quantitative FLAIR signal analysis clearly identifies Wyler III and IV HS. Quantitative FLAIR signal analysis may be helpful to identify Wyler II HS. (orig.)

  5. Comparison of whole body MR angiography at 1.5 and 3 Tesla in patients with hereditary hyperlipidemia

    Energy Technology Data Exchange (ETDEWEB)

    Bannas, Peter; Finck-Wedel, Anna Katharina; Buhk, Jan-Hendrik; Bley, Thorsten Alexander; Koops, Andreas; Adam, Gerhard; Weber, Christoph (Dept. of Diagnostic and Interventional Radiology, Univ. Hospital Hamburg-Eppendorf, Hamburg (Germany)), email: p.bannas@uke.uni-hamburg.de; Kooijman, Hendrik (Philips Medical Systems, Hamburg (Germany)); Beil, Frank-Ulrich (Dept. of Internal Medicine, Univ. Hospital Hamburg-Eppendorf, Hamburg (Germany))

    2011-06-15

    Background Patients suffering from hereditary hyperlipidemia have a high risk for premature cardiovascular disease and death as a consequence of accelerated atherosclerosis. Purpose To prospectively and intra-individually compare image quality and detectability of stenoses in contrast enhanced whole-body MRA (WBMRA) at 1.5 and 3 Tesla (T) in patients with hereditary hyperlipidemia. Material and Methods Twenty-seven patients with hereditary hyperlipidemia received a 1.5 and 3 T gadopentetate dimeglumine contrast-enhanced WBMRA. Twenty-three defined arterial segments were analyzed regarding depiction of target vessels and image quality according to a 5-point-scale ('not evaluable' to 'excellent'). Wilcoxon matched pair test was performed for comparison. Forty-three defined arterial segments were analyzed for the degree of stenosis (0%, 1-49%, 50-99% and 100%) as well as vessel alterations such as aneurysms. Chi-square test was performed for comparison. Results 1.5 T and 3 T scans yielded WBMRA with diagnostic quality in all patients. In seven of 23 arterial segments (30.4%) image quality was rated significantly higher at 3 T, whereas there was no significant difference in the remaining 16 segments between WBMRA at 1.5 T and 3 T. All relevant stenoses (n = 5), occlusions (n = 6), and aneurysms (n = 3) were evaluated similarly at both field strengths. Conclusion WBMRA can be performed at 1.5 T and 3 T with diagnostic image quality. Image quality was significantly higher at 3 T than at 1.5 T in only 30.4% of the arterial segments. In order to effectively take advantage of the higher field strength, further optimization of sequence parameters and injection protocols for WBMRA at 3 T is necessary

  6. High resolution emission tomography; Tomographie d`emission haute resolution

    Energy Technology Data Exchange (ETDEWEB)

    Charon, Y.; Laniece, P.; Mastrippolito, R.; Pinot, L.; Ploux, L.; Valda Ochoa, A.; Valentin, L. [Groupe I.P.B., Experimental Research Division, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-11-01

    We have developed an original high resolution tomograph for in-vivo small animal imaging. A first prototype is under evaluation. Initial results of its characterisation are presented. (authors) 3 figs.

  7. VT Hydrography Dataset - High Resolution NHD

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The Vermont Hydrography Dataset (VHD) is compliant with the local resolution (also known as High Resolution) National Hydrography Dataset (NHD)...

  8. High-resolution infrared imaging

    Science.gov (United States)

    Falco, Charles M.

    2010-08-01

    The hands and mind of an artist are intimately involved in the creative process of image formation, intrinsically making paintings significantly more complex than photographs to analyze. In spite of this difficulty, several years ago the artist David Hockney and I identified optical evidence within a number of paintings that demonstrated artists began using optical projections as early as c1425 - nearly 175 years before Galileo - as aids for producing portions of their images. In the course of our work, Hockney and I developed insights that I have been applying to a new approach to computerized image analysis. Recently I developed and characterized a portable high resolution infrared for capturing additional information from paintings. Because many pigments are semi-transparent in the IR, in a number of cases IR photographs ("reflectograms") have revealed marks made by the artists that had been hidden under paint ever since they were made. I have used this IR camera to capture photographs ("reflectograms") of hundreds of paintings in over a dozen museums on three continents and, in some cases, these reflectograms have provided new insights into decisions the artists made in creating the final images that we see in the visible.

  9. In vitro assessment of MRI issues at 3-Tesla for a breast tissue expander with a remote port.

    Science.gov (United States)

    Linnemeyer, Hannah; Shellock, Frank G; Ahn, Christina Y

    2014-04-01

    A patient with a breast tissue expander may require a diagnostic assessment using magnetic resonance imaging (MRI). To ensure patient safety, this type of implant must undergo in vitro MRI testing using proper techniques. Therefore, this investigation evaluated MRI issues (i.e., magnetic field interactions, heating, and artifacts) at 3-Tesla for a breast tissue expander with a remote port. A breast tissue expander with a remote port (Integra Breast Tissue Expander, Model 3612-06 with Standard Remote Port, PMT Corporation, Chanhassen, MN) underwent evaluation for magnetic field interactions (translational attraction and torque), MRI-related heating, and artifacts using standardized techniques. Heating was evaluated by placing the implant in a gelled-saline-filled phantom and MRI was performed using a transmit/receive RF body coil at an MR system reported, whole body averaged specific absorption rate of 2.9-W/kg. Artifacts were characterized using T1-weighted and GRE pulse sequences. Magnetic field interactions were not substantial and, thus, will not pose a hazard to a patient in a 3-Tesla or less MRI environment. The highest temperature rise was 1.7°C, which is physiologically inconsequential. Artifacts were large in relation to the remote port and metal connector of the implant but will only present problems if the MR imaging area of interest is where these components are located. A patient with this breast tissue expander with a remote port may safely undergo MRI at 3-Tesla or less under the conditions used for this investigation. These findings are the first reported at 3-Tesla for a tissue expander. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Ventricular Assist Device implant (AB 5000 prototype cannula: In vitro assessment of MRI issues at 3-Tesla

    Directory of Open Access Journals (Sweden)

    Valencerina Samuel

    2008-05-01

    Full Text Available Abstract Purpose To evaluate MRI issues at 3-Tesla for a ventricular assist device (VAD. Methods The AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached (Abiomed, Inc., Danvers, MA was evaluated for magnetic field interactions, heating, and artifacts at 3-Tesla. MRI-related heating was assessed with the device in a gelled-saline-filled, head/torso phantom using a transmit/received RF body coil while performing MRI at a whole body averaged SAR of 3-W/kg for 15-min. Artifacts were assessed for the main metallic component of this VAD (atrial cannula using T1-weighted, spin echo and gradient echo pulse sequences. Results The AB5000 Ventricle with the prototype In-Flow Cannula and Out-Flow Cannula attached showed relatively minor magnetic field interactions that will not cause movement in situ. Heating was not excessive (highest temperature change, +0.8°C. Artifacts may create issues for diagnostic imaging if the area of interest is in the same area or close to the implanted metallic component of this VAD (i.e., the venous cannula. Conclusion The results of this investigation demonstrated that it would be acceptable for a patient with this VAD (AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached to undergo MRI at 3-Tesla or less. Notably, it is likely that the operation console for this device requires positioning a suitable distance (beyond the 100 Gauss line or in the MR control room from the 3-Tesla MR system to ensure proper function of the VAD.

  11. High-resolution neutron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Mikerov, V.I. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Zhitnik, I.A. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Ignat`ev, A.P. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Isakov, A.I. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Korneev, V.V. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Krutov, V.V. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Kuzin, S.V. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Oparin, S.N. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Pertsov, A.A. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Podolyak, E.R. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Sobel`man, I.I. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Tindo, I.P. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation); Tukarev, B.A. [P.N. Lebedev Physical Inst., RAN, Moscow (Russian Federation)

    1995-12-31

    A neutron tomography technique with a coordinate resolution of several tens of micrometers has been developed. Our results indicate that the technique resolves details with dimensions less than 100 {mu}m and measures a linear attenuation of less than {approx} 0.1 cm{sup -1}. Tomograms can be reconstructed using incomplete data. Limits on the resolution of the restored pattern are analyzed, and ways to improve the sensitivity of the technique are discussed. (orig.).

  12. Variations of the posterior cerebral artery diagnosed by MR angiography at 3 tesla

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, Akira; Saito, Naoko; Takahashi, Masahiro; Okano, Nanami; Tanisaka, Megumi [Saitama Medical University International Medical Center, Department of Diagnostic Radiology, Hidaka, Saitama (Japan)

    2016-02-15

    Fenestration, early bifurcation, and duplication of the posterior cerebral artery (PCA) and the so-called hyperplastic anterior choroidal artery (AChA), considered a variation of the PCA, are rare. We evaluated the prevalence and characteristic features of these PCA variations on magnetic resonance (MR) angiography. We reviewed intracranial MR angiographic images of 2402 patients examined using a 3-tesla scanner. Images from the skull base to the intracranial region were obtained using the standard time-of-flight technique. We excluded images of 52 patients with insufficient image quality or occlusion of the PCA(s) and retrospectively evaluated the images of 2350 patients using a picture archiving and communication system. We observed PCA fenestration in eight (0.34 %) patients, most at the P1 segment and P1-P2 junction and all small in size, early bifurcation at the P1-P2 junction or proximal P2A segment in eight (0.34 %) patients, complete duplication in one patient, and hyperplastic AChA in 13 (0.55 %) patients. Eleven of the 13 hyperplastic AChAs supplied only the territory of the temporal branch of the PCA, and the remaining two supplied the entire territory of the PCA. We observed PCA variations in 30 (1.28 %) patients. We believe the name ''hyperplastic AChA'' inaccurately describes variations of the PCA in which the AChA supplies part of or all of the territory of the PCA and propose ''accessory PCA'' to describe an AChA that supplies part of the territory of the PCA or ''replaced PCA'' to describe that vessel that supplies the territory all branches of the PCA. (orig.)

  13. White Matter Brain Lesions in Midlife Familial Hypercholesterolemic Patients at 3-Tesla Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, S.A.; O' Regan, D.P.; Fitzpatrick, J.; Neuwirth, C.; Potter, E.; Tosi, I.; Hajnal, J.V.; Naoumova, R.P. (Imaging Sciences Dept. and Clinical Research Facility, MRC Clinical Sciences Centre, London (GB))

    2008-03-15

    Background: Patients with hypercholesterolemia of 60 years and older have an increased risk for white matter brain lesions and dementia. Purpose: To investigate whether patients with familial hypercholesterolemia (FH) develop white matter lesions at 3-Tesla (T) MRI as early as in midlife. Material and Methods: Non-diabetic, non-smoking, and non-hypertensive heterozygous FH patients on treatment with maximally tolerated dose of a statin for more than 5 years (n = 14) and matched controls (n = 22) aged 25 to 60 years of age were studied. Imaging was performed at 3T with a fluid-attenuated T2-weighted MR pulse sequence and a T1-weighted spin-echo pulse sequence following 10 ml of i.v. gadopentetate dimeglumine. Images were evaluated by two independent readers. Fasting blood samples were taken. Student's t test was employed at P<0.05. Results: Three volunteers and one FH patient had white matter lesions (P<0.53). No other evidence of past ischemic stroke was observed. Mean total serum cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the FH group (6.0+-1.1 vs. 5.1+-0.9 mmol/l, P<0.02 and 4.1+-0.9 vs. 3.1+-0.8 mmol/l, P<0.004, respectively). Conclusion: Heterozygous FH patients on statin treatment in the age range of 25 to 60 years are not at increased risk of white matter lesions at 3T MRI

  14. Implementation of fast macromolecular proton fraction mapping on 1.5 and 3 Tesla clinical MRI scanners: preliminary experience

    Science.gov (United States)

    Yarnykh, V.; Korostyshevskaya, A.

    2017-08-01

    Macromolecular proton fraction (MPF) is a biophysical parameter describing the amount of macromolecular protons involved into magnetization exchange with water protons in tissues. MPF represents a significant interest as a magnetic resonance imaging (MRI) biomarker of myelin for clinical applications. A recent fast MPF mapping method enabled clinical translation of MPF measurements due to time-efficient acquisition based on the single-point constrained fit algorithm. However, previous MPF mapping applications utilized only 3 Tesla MRI scanners and modified pulse sequences, which are not commonly available. This study aimed to test the feasibility of MPF mapping implementation on a 1.5 Tesla clinical scanner using standard manufacturer’s sequences and compare the performance of this method between 1.5 and 3 Tesla scanners. MPF mapping was implemented on 1.5 and 3 Tesla MRI units of one manufacturer with either optimized custom-written or standard product pulse sequences. Whole-brain three-dimensional MPF maps obtained from a single volunteer were compared between field strengths and implementation options. MPF maps demonstrated similar quality at both field strengths. MPF values in segmented brain tissues and specific anatomic regions appeared in close agreement. This experiment demonstrates the feasibility of fast MPF mapping using standard sequences on 1.5 T and 3 T clinical scanners.

  15. Is the Ellipsoid Formula the New Standard for 3-Tesla MRI Prostate Volume Calculation without Endorectal Coil?

    Science.gov (United States)

    Haas, Matthias; Günzel, Karsten; Miller, Kurt; Hamm, Bernd; Cash, Hannes; Asbach, Patrick

    2017-01-01

    Prostate volume in multiparametric MRI (mpMRI) is of clinical importance. For 3-Tesla mpMRI without endorectal coil, there is no distinctive standard for volume calculation. We tested the accuracy of the ellipsoid formula with planimetric volume measurements as reference and investigated the correlation of gland volume and cancer detection rate on MRI/ultrasound (MRI/US) fusion-guided biopsy. One hundred forty-three patients with findings on 3-Tesla mpMRI suspicious of cancer and subsequent MRI/US fusion-guided targeted biopsy and additional systematic biopsy were analyzed. T2-weighted images were used for measuring the prostate diameters and for planimetric volume measurement by a segmentation software. Planimetric and calculated prostate volumes were compared with clinical data. The median prostate volume was 48.1 ml (interquartile range (IQR) 36.9-62.1 ml). Volume calculated by the ellipsoid formula showed a strong concordance with planimetric volume, with a tendency to underestimate prostate volume (median volume 43.1 ml (IQR 31.2-58.8 ml); r = 0.903, p < 0.001). There was a moderate, significant inverse correlation of prostate volume to a positive biopsy result (r = -0.24, p = 0.004). The ellipsoid formula gives sufficient approximation of prostate volume on 3-Tesla mpMRI without endorectal coil. It allows a fast, valid volume calculation in prostate MRI datasets.

  16. Nonenhanced hybridized arterial spin labeled magnetic resonance angiography of the extracranial carotid arteries using a fast low angle shot readout at 3 Tesla

    National Research Council Canada - National Science Library

    Ioannis Koktzoglou; Matthew T Walker; Joel R Meyer; Ian G Murphy; Robert R Edelman

    2016-01-01

    ... (MRA) of the extracranial carotid arteries using a fast low angle shot (FLASH) readout at 3 Tesla. Methods In this retrospective, institutional review board-approved and HIPAA-compliant study, we evaluated the image quality...

  17. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  18. DESIR high resolution separator at GANIL, France

    Directory of Open Access Journals (Sweden)

    Toprek Dragan

    2012-01-01

    Full Text Available A high-resolution separator for the SPIRAL2/DESIR project at GANIL has been designed. The extracted isotopes from SPIRAL2 will be transported to and cooled in a RFQ cooler yielding beams with very low transverse emittance and energy spread. These beams will then be accelerated to 60 keV and sent to a high-resolution mass separator where a specific isotope will be selected. The good beam properties extracted from the RFQ cooler will allow one to obtain a mass resolution of č26000 with the high-resolution mass separator.

  19. High Resolution Silicon Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes a plan to build a prototype small stroke, high precision deformable mirror suitable for space-based operation in systems for high-resolution...

  20. Single-row vs. double-row arthroscopic rotator cuff repair: clinical and 3 Tesla MR arthrography results.

    Science.gov (United States)

    Tudisco, Cosimo; Bisicchia, Salvatore; Savarese, Eugenio; Fiori, Roberto; Bartolucci, Dario A; Masala, Salvatore; Simonetti, Giovanni

    2013-01-27

    Arthroscopic rotator cuff repair has become popular in the last few years because it avoids large skin incisions and deltoid detachment and dysfunction. Earlier arthroscopic single-row (SR) repair methods achieved only partial restoration of the original footprint of the tendons of the rotator cuff, while double-row (DR) repair methods presented many biomechanical advantages and higher rates of tendon-to-bone healing. However, DR repair failed to demonstrate better clinical results than SR repair in clinical trials. MR imaging at 3 Tesla, especially with intra-articular contrast medium (MRA), showed a better diagnostic performance than 1.5 Tesla in the musculoskeletal setting. The objective of this study was to retrospectively evaluate the clinical and 3 Tesla MRA results in two groups of patients operated on for a medium-sized full-thickness rotator cuff tear with two different techniques. The first group consisted of 20 patients operated on with the SR technique; the second group consisted of 20 patients operated on with the DR technique. All patients were evaluated at a minimum of 3 years after surgery. The primary end point was the re-tear rate at 3 Tesla MRA. The secondary end points were the Constant-Murley Scale (CMS), the Simple Shoulder Test (SST) scores, surgical time and implant expense. The mean follow-up was 40 months in the SR group and 38.9 months in the DR group. The mean postoperative CMS was 70 in the SR group and 68 in the DR group. The mean SST score was 9.4 in the SR group and 10.1 in the DR group. The re-tear rate was 60% in the SR group and 25% in the DR group. Leakage of the contrast medium was observed in all patients. To the best of our knowledge, this is the first report on 3 Tesla MRA in the evaluation of two different techniques of rotator cuff repair. DR repair resulted in a statistically significant lower re-tear rate, with longer surgical time and higher implant expense, despite no difference in clinical outcomes. We think that

  1. Single-row vs. double-row arthroscopic rotator cuff repair: clinical and 3 Tesla MR arthrography results

    Directory of Open Access Journals (Sweden)

    Tudisco Cosimo

    2013-01-01

    Full Text Available Abstract Background Arthroscopic rotator cuff repair has become popular in the last few years because it avoids large skin incisions and deltoid detachment and dysfunction. Earlier arthroscopic single-row (SR repair methods achieved only partial restoration of the original footprint of the tendons of the rotator cuff, while double-row (DR repair methods presented many biomechanical advantages and higher rates of tendon-to-bone healing. However, DR repair failed to demonstrate better clinical results than SR repair in clinical trials. MR imaging at 3 Tesla, especially with intra-articular contrast medium (MRA, showed a better diagnostic performance than 1.5 Tesla in the musculoskeletal setting. The objective of this study was to retrospectively evaluate the clinical and 3 Tesla MRA results in two groups of patients operated on for a medium-sized full-thickness rotator cuff tear with two different techniques. Methods The first group consisted of 20 patients operated on with the SR technique; the second group consisted of 20 patients operated on with the DR technique. All patients were evaluated at a minimum of 3 years after surgery. The primary end point was the re-tear rate at 3 Tesla MRA. The secondary end points were the Constant-Murley Scale (CMS, the Simple Shoulder Test (SST scores, surgical time and implant expense. Results The mean follow-up was 40 months in the SR group and 38.9 months in the DR group. The mean postoperative CMS was 70 in the SR group and 68 in the DR group. The mean SST score was 9.4 in the SR group and 10.1 in the DR group. The re-tear rate was 60% in the SR group and 25% in the DR group. Leakage of the contrast medium was observed in all patients. Conclusions To the best of our knowledge, this is the first report on 3 Tesla MRA in the evaluation of two different techniques of rotator cuff repair. DR repair resulted in a statistically significant lower re-tear rate, with longer surgical time and higher implant

  2. High-Resolution Data for a Low-Resolution World

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Brendan Williams [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-10

    In the past 15 years, the upper section of Cañon de Valle has been severely altered by wildfires and subsequent runoff events. Loss of root structures on high-angle slopes results in debris flow and sediment accumulation in the narrow canyon bottom. The original intent of the study described here was to better understand the changes occurring in watershed soil elevations over the course of several post-fire years. An elevation dataset from 5 years post-Cerro Grande fire was compared to high-resolution LiDAR data from 14 years post-Cerro Grande fire (also 3 years post-Las Conchas fire). The following analysis was motivated by a problematic comparison of these datasets of unlike resolution, and therefore focuses on what the data reveals of itself. The objective of this study is to highlight the effects vegetation can have on remote sensing data that intends to read ground surface elevation.

  3. Hip imaging of avascular necrosis at 7 Tesla compared with 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Theysohn, J.M.; Kraff, O.; Theysohn, N.; Orzada, S.; Lauenstein, T.C. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Institute for Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Landgraeber, S. [University Hospital Essen, Department of Orthopedic Surgery, Essen (Germany); Ladd, M.E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); German Cancer Research Center, Department of Medical Physics in Radiology, Heidelberg (Germany)

    2014-05-15

    To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities. Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data. 7-T imaging of the femoral joints, as well as 3-T imaging, achieved ''good'' to ''very good'' quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS > 2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9-4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1-2.9); to a lesser extent also GRE sequences (7 T: 2.9-3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2-2.6) and cartilage defects (2.5-3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5). 7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight

  4. High resolution studies of massive primordial haloes

    CERN Document Server

    Latif, M A; Schmidt, W; Niemeyer, J

    2012-01-01

    Atomic cooling haloes with T_vir > 10^4 K are the most plausible sites for the formation of the first galaxies. In this article, we aim to study the implications of gravity driven turbulence in protogalactic haloes. By varying the resolution per Jeans length, we explore whether the turbulent cascade is resolved well enough to obtain converged results. We have performed high resolution cosmological simulations using the adaptive mesh refinement code Enzo including a subgrid-scale turbulence model to study the role of unresolved turbulence. We compared the results of three different Jeans resolutions from 16 to 64 cells. While radially averaged profiles roughly agree at different resolutions, differences in the morphology reveal that even the highest resolution employed provides no convergence. Moreover, taking into account unresolved turbulence significantly influences the morphology of a halo. We have quantified the properties of the high-density clumps in the halo. These clumps are gravitationally unbound wi...

  5. High Resolution Silicon Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal we describe a plan to build a deformable mirror suitable for space-based operation in systems for high-resolution imaging. The prototype DM will be...

  6. High range resolution micro-Doppler analysis

    Science.gov (United States)

    Cammenga, Zachary A.; Smith, Graeme E.; Baker, Christopher J.

    2015-05-01

    This paper addresses use of the micro-Doppler effect and the use of high range-resolution profiles to observe complex targets in complex target scenes. The combination of micro-Doppler and high range-resolution provides the ability to separate the motion of complex targets from one another. This ability leads to the differentiation of targets based on their micro-Doppler signatures. Without the high-range resolution, this would not be possible because the individual signatures would not be separable. This paper also addresses the use of the micro-Doppler information and high range-resolution profiles to generate an approximation of the scattering properties of a complex target. This approximation gives insight into the structure of the complex target and, critically, is created without using a pre-determined target model.

  7. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  8. High resolution SAR applications and instrument design

    Science.gov (United States)

    Dionisio, C.; Torre, A.

    1993-01-01

    The Synthetic Aperture Radar (SAR) has viewed, in the last two years, a huge increment of interest from many preset and potential users. The good spatial resolution associated to the all weather capability lead to considering SAR not only a scientific instrument but a tool for verifying and controlling the daily human relationships with the Earth Environment. New missions were identified for SAR as spatial resolution became lower than three meters: disasters, pollution, ships traffic, volcanic eruptions, earthquake effect are only a few of the possible objects which can be effectively detected, controlled and monitored by SAR mounted on satellites. High resolution radar design constraints and dimensioning are discussed.

  9. 4MOST: the high-resolution spectrograph

    Science.gov (United States)

    Seifert, W.; Xu, W.; Buschkamp, P.; Feiz, C.; Saviauk, A.; Barden, S.; Quirrenbach, A.; Mandel, H.

    2016-08-01

    4MOST (4-meter Multi-Object Spectroscopic Telescope) is a wide-field, fiber-feed, high-multiplex spectroscopic survey facility to be installed on the 4-meter ESO telescope VISTA in Chile. It consists of two identical low resolution spectrographs and one high resolution spectrograph. The instrument is presently in the preliminary design phase and expected to get operational end of 2022. The high resolution spectrograph will afford simultaneous observations of up to 812 targets - over a hexagonal field of view of 4.1 sq.degrees on sky - with a spectral resolution R>18,000 covering a wavelength range from 393 to 679nm in three channels. In this paper we present the optical and mechanical design of the high resolution spectrograph (HRS) as prepared for the review at ESO, Garching. The expected performance including the highly multiplexed fiber slit concept is simulated and its impact on the optical performance given. We show the thermal and finite element analyses and the resulting stability of the spectrograph under operational conditions.

  10. Magnetic resonance imaging evaluation after implantation of a titanium cervical disc prosthesis: a comparison of 1.5 and 3 Tesla magnet strength.

    Science.gov (United States)

    Sundseth, Jarle; Jacobsen, Eva A; Kolstad, Frode; Nygaard, Oystein P; Zwart, John A; Hol, Per K

    2013-10-01

    Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover(®) cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR. Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image sequences one year following anterior cervical discectomy with arthroplasty. Two neuroradiologists evaluated the images by consensus. Emphasis was made on signal changes in medulla at all levels and visualization of root canals at operated and adjacent levels. A "blur artifact ratio" was calculated and defined as the height of the artifact on T1 sagittal images related to the operated level. The artifacts induced in 1.5 and 3 Tesla MR were of entirely different character and evaluation of the spinal cord at operated level was impossible in both magnets. Artifacts also made the root canals difficult to assess at operated level and more pronounced in the 3 Tesla MR. At the adjacent levels however, the spinal cord and root canals were completely visualized in all patients. The "blur artifact" induced at operated level was also more pronounced in the 3 Tesla MR. The artifact induced by the Discover(®) titanium disc prosthesis in both 1.5 and 3 Tesla MR, makes interpretation of the spinal cord impossible and visualization of the root canals difficult at operated level. Adjusting the MR sequences to produce the least amount of artifact is important.

  11. High-Resolution PET Detector. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Joel

    2014-03-26

    The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface.

  12. A robust multi-shot scan strategy for high-resolution diffusion weighted MRI enabled by multiplexed sensitivity-encoding (MUSE).

    Science.gov (United States)

    Chen, Nan-Kuei; Guidon, Arnaud; Chang, Hing-Chiu; Song, Allen W

    2013-05-15

    Diffusion weighted magnetic resonance imaging (DWI) data have been mostly acquired with single-shot echo-planar imaging (EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in single-shot EPI, even when the parallel imaging (usually at an acceleration factor of 2) is incorporated. Multi-shot acquisition strategies could potentially achieve higher spatial resolution and fidelity, but they are generally susceptible to motion-induced phase errors among excitations that are exacerbated by diffusion sensitizing gradients, rendering the reconstructed images unusable. It has been shown that shot-to-shot phase variations may be corrected using navigator echoes, but at the cost of imaging throughput. To address these challenges, a novel and robust multi-shot DWI technique, termed multiplexed sensitivity-encoding (MUSE), is developed here to reliably and inherently correct nonlinear shot-to-shot phase variations without the use of navigator echoes. The performance of the MUSE technique is confirmed experimentally in healthy adult volunteers on 3Tesla MRI systems. This newly developed technique should prove highly valuable for mapping brain structures and connectivities at high spatial resolution for neuroscience studies.

  13. Quantitative assessment of right ventricular function and pulmonary regurgitation in surgically repaired tetralogy of Fallot using 256-slice CT: comparison with 3-Tesla MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Yuzo; Yonezawa, Masato; Matsuo, Yoshio; Kamitani, Takeshi; Higuchi, Ko; Honda, Hiroshi [Graduate School of Medical Sciences, Kyushu University, Department of Clinical Radiology, Higashi-ku, Fukuoka (Japan); Nagao, Michinobu; Kawanami, Satoshi [Graduate School of Medical Sciences, Kyushu University, Department of Molecular Imaging and Diagnosis, Higashi-ku, Fukuoka (Japan); Yamamura, Kenichiro [Graduate School of Medical Sciences, Kyushu University, Department of Pediatrics, Higashi-ku, Fukuoka (Japan); Sakamoto, Ichiro [Graduate School of Medical Sciences, Kyushu University, Department of Cardiovascular Medicine, Higashi-ku, Fukuoka (Japan); Shiokawa, Yuichi [Graduate School of Medical Sciences, Kyushu University, Department of Cardiovascular Surgery, Higashi-ku, Fukuoka (Japan); Yabuuchi, Hidetake [Graduate School of Medical Sciences, Kyushu University, Department of Health Sciences, Higashi-ku, Fukuoka (Japan)

    2014-12-15

    To compare 256-slice cardiac computed tomography (CCT) with cardiac magnetic resonance (CMR) imaging to assess right ventricular (RV) function and pulmonary regurgitant fraction (PRF) in patients with repaired tetralogy of Fallot (TOF). Thirty-three consecutive patients with repaired TOF underwent retrospective ECG-gated CCT and 3-Tesla CMR. RV and left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) were measured using CCT and CMR. PRF-CCT (%) was defined as (RVSV - LVSV)/RVSV. PRF-CMR (%) was measured by the phase-contrast method. Repeated measurements were performed to determine intra- and interobserver variability. CCT measurements, including PRF, correlated highly with the CMR reference (r = 0.71-0.96). CCT overestimated RVEDV (mean difference, 17.1 ± 2.9 ml), RVESV (12.9 ± 2.1 ml) and RVSV (4.2 ± 2.0 ml), and underestimated RVEF (-2.6 ± 1.0 %) and PRF (-9.1 ± 2.0 %) compared with CMR. The limits of agreement between CCT and CMR were in a good range for all measurements. The variability in CCT measurements was lower than those in CMR. The estimated effective radiation dose was 7.6 ± 2.6 mSv. 256-slice CCT can assess RV function and PRF with relatively low dose radiation exposure in patients with repaired TOF, but overestimates RV volume and underestimates PRF. (orig.)

  14. First test of a power-pulsed electronics system on a GRPC detector in a 3-Tesla magnetic field

    CERN Document Server

    Caponetto, L; de la Taille, C; Dulucq, F; Kieffer, R; Laktineh, I; Lumb, N; Mirabito, L; Seguin-Moreau, N

    2012-01-01

    An important technological step towards the realization of an ultra-granular hadronic calorimeter to be used in the future International Linear Collider (ILC) experiments has been made. A 33X50 cm2 GRPC detector equipped with a power-pulsed electronics board offering a 1cm2 lateral segmentation was successfully tested in a 3-Tesla magnet operating at the H2 beam line of the CERN SPS. An important reduction of power consumption with no deterioration of the detector performance is obtained when the power-pulsing mode is applied. This important result shows that ultra-granular calorimeters for ILC experiments are not only an attractive but also a realistic option.

  15. A High Resolution Scale-of-four

    Science.gov (United States)

    Fitch, V.

    1949-08-25

    A high resolution scale-of-four has been developed to be used in conjunction with the nuclear particle detection devices in applications where the counting rate is unusually high. Specifically, it is intended to precede the commercially available medium resolution scaling circuits and so decrease the resolving time of the counting system. The circuit will function reliably on continuously recurring pulses separated by less than 0.1 microseconds. It will resolve two pulses (occurring at a moderate repetition rate) which are spaced at 0.04 microseconds. A five-volt input signal is sufficient to actuate the device.

  16. Single shot high resolution digital holography.

    Science.gov (United States)

    Khare, Kedar; Ali, P T Samsheer; Joseph, Joby

    2013-02-11

    We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.

  17. Diffusion kurtosis imaging of the liver at 3 Tesla: in vivo comparison to standard diffusion-weighted imaging.

    Science.gov (United States)

    Budjan, Johannes; Sauter, Elke A; Zoellner, Frank G; Lemke, Andreas; Wambsganss, Jens; Schoenberg, Stefan O; Attenberger, Ulrike I

    2017-01-01

    Background Functional techniques like diffusion-weighted imaging (DWI) are gaining more and more importance in liver magnetic resonance imaging (MRI). Diffusion kurtosis imaging (DKI) is an advanced technique that might help to overcome current limitations of DWI. Purpose To evaluate DKI for the differentiation of hepatic lesions in comparison to conventional DWI at 3 Tesla. Material and Methods Fifty-six consecutive patients were examined using a routine abdominal MR protocol at 3 Tesla which included DWI with b-values of 50, 400, 800, and 1000 s/mm(2). Apparent diffusion coefficient maps were calculated applying a standard mono-exponential fit, while a non-Gaussian kurtosis fit was used to obtain DKI maps. ADC as well as Kurtosis-corrected diffusion ( D) values were quantified by region of interest analysis and compared between lesions. Results Sixty-eight hepatic lesions (hepatocellular carcinoma [HCC] [n = 25]; hepatic adenoma [n = 4], cysts [n = 18]; hepatic hemangioma [HH] [n = 18]; and focal nodular hyperplasia [n = 3]) were identified. Differentiation of malignant and benign lesions was possible based on both DWI ADC as well as DKI D-values ( P values were in the range of 0.04 to < 0.0001). Conclusion In vivo abdominal DKI calculated using standard b-values is feasible and enables quantitative differentiation between malignant and benign liver lesions. Assessment of conventional ADC values leads to similar results when using b-values below 1000 s/mm(2) for DKI calculation.

  18. Usefulness of 3-Tesla cardiac magnetic resonance imaging in the assessment of aortic stenosis severity in routine clinical practice.

    Science.gov (United States)

    Levy, Franck; Iacuzio, Laura; Civaia, Filippo; Rusek, Stephane; Dommerc, Carine; Hugues, Nicolas; Alexandrescu, Clara; Dor, Vincent; Tribouilloy, Christophe; Dreyfus, Gilles

    2016-11-01

    Recently, 1.5-Tesla cardiac magnetic resonance imaging (CMR) was reported to provide a reliable alternative to transthoracic echocardiography (TTE) for the quantification of aortic stenosis (AS) severity. Few data are available using higher magnetic field strength MRI systems in this context. To evaluate the feasibility and reproducibility of the assessment of aortic valve area (AVA) using 3-Tesla CMR in routine clinical practice, and to assess concordance between TTE and CMR for the estimation of AS severity. Ninety-one consecutive patients (60 men; mean age 74±10years) with known AS documented by TTE were included prospectively in the study. All patients underwent comprehensive TTE and CMR examination, including AVA estimation using the TTE continuity equation (0.81±0.18cm(2)), direct CMR planimetry (CMRp) (0.90±0.22cm(2)) and CMR using Hakki's formula (CMRhk), a simplified Gorlin formula (0.70±0.19cm(2)). Although significant agreement with TTE was found for CMRp (r=0.72) and CMRhk (r=0.66), CMRp slightly overestimated (bias=0.11±0.18cm(2)) and CMRhk slightly underestimated (bias=-0.11±0.17cm(2)) AVA compared with TTE. Inter- and intraobserver reproducibilities of CMR measurements were excellent (r=0.72 and r=0.74 for CMRp and r=0.88 and r=0.92 for peak aortic velocity, respectively). 3-Tesla CMR is a feasible, radiation-free, reproducible imaging modality for the estimation of severity of AS in routine practice, knowing that CMRp tends to overestimate AVA and CMRhk to underestimate AVA compared with TTE. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Utility and limitations of 3-Tesla diffusion-weighted magnetic resonance imaging for differentiation of renal tumors

    Energy Technology Data Exchange (ETDEWEB)

    Sevcenco, S., E-mail: sabina.sevcenco@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Heinz-Peer, G., E-mail: gertraud.heinz-peer@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Ponhold, L., E-mail: lothar.ponhold@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Javor, D., E-mail: domagoj.javor@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Kuehhas, F.E., E-mail: frenklin.kuehhas@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Klingler, H.C., E-mail: christoph.klingler@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Remzi, M., E-mail: mesut.remzi@gmx.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Weibl, P., E-mail: peter.weibl@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Shariat, S.F., E-mail: sfshariat@gmail.com [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Baltzer, P.A., E-mail: pascal.baltzer@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria)

    2014-06-15

    Objective: To investigate utility and limitations of 3-Tesla diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiation of benign versus malignant renal lesions and renal cell carcinoma (RCC) subtypes. Materials and methods: Sixty patients with 71 renal lesions underwent 3 Tesla DW-MRI of the kidney before diagnostic tissue confirmation. The images were retrospectively evaluated blinded to histology. Single-shot echo-planar imaging was used as the DW imaging technique. Apparent diffusion coefficient (ADC) values were measured and compared with histopathological characteristics. Results: There were 54 malignant and 17 benign lesions, 46 lesions being small renal masses ≤4 cm. Papillary RCC lesions had lower ADC values (p = 0.029) than other RCC subtypes (clear cell or chromophobe). Diagnostic accuracy of DW-MRI for differentiation of papillary from non-papillary RCC was 70.3% resulting in a sensitivity and specificity of 64.3% (95% CI, 35.1–87.2) and 77.1 (95% CI, 59.9–89.6%). Accuracy increased to 83.7% in small renal masses (≤4 cm diameter) and sensitivity and specificity were 75.0% and 88.5%, respectively. The ADC values did not differ significantly between benign and malignant renal lesions (p = 0.45). Conclusions: DW-MRI seems to distinguish between papillary and other subtypes of RCCs especially in small renal masses but could not differentiate between benign and malignant renal lesions. Therefore, the use of DW-MRI for preoperative differentiation of renal lesions is limited.

  20. Customized MFM probes with high lateral resolution

    Directory of Open Access Journals (Sweden)

    Óscar Iglesias-Freire

    2016-07-01

    Full Text Available Magnetic force microscopy (MFM is a widely used technique for magnetic imaging. Besides its advantages such as the high spatial resolution and the easy use in the characterization of relevant applied materials, the main handicaps of the technique are the lack of control over the tip stray field and poor lateral resolution when working under standard conditions. In this work, we present a convenient route to prepare high-performance MFM probes with sub-10 nm (sub-25 nm topographic (magnetic lateral resolution by following an easy and quick low-cost approach. This allows one to not only customize the tip stray field, avoiding tip-induced changes in the sample magnetization, but also to optimize MFM imaging in vacuum (or liquid media by choosing tips mounted on hard (or soft cantilevers, a technology that is currently not available on the market.

  1. High-resolution electrohydrodynamic jet printing

    Science.gov (United States)

    Park, Jang-Ung; Hardy, Matt; Kang, Seong Jun; Barton, Kira; Adair, Kurt; Mukhopadhyay, Deep Kishore; Lee, Chang Young; Strano, Michael S.; Alleyne, Andrew G.; Georgiadis, John G.; Ferreira, Placid M.; Rogers, John A.

    2007-10-01

    Efforts to adapt and extend graphic arts printing techniques for demanding device applications in electronics, biotechnology and microelectromechanical systems have grown rapidly in recent years. Here, we describe the use of electrohydrodynamically induced fluid flows through fine microcapillary nozzles for jet printing of patterns and functional devices with submicrometre resolution. Key aspects of the physics of this approach, which has some features in common with related but comparatively low-resolution techniques for graphic arts, are revealed through direct high-speed imaging of the droplet formation processes. Printing of complex patterns of inks, ranging from insulating and conducting polymers, to solution suspensions of silicon nanoparticles and rods, to single-walled carbon nanotubes, using integrated computer-controlled printer systems illustrates some of the capabilities. High-resolution printed metal interconnects, electrodes and probing pads for representative circuit patterns and functional transistors with critical dimensions as small as 1μm demonstrate potential applications in printed electronics.

  2. Smartphone microendoscopy for high resolution fluorescence imaging

    CERN Document Server

    Hong, Xiangqian; Mugler, Dale H; Yu, Bing

    2016-01-01

    High resolution optical endoscopes are increasingly used in diagnosis of various medical conditions of internal organs, such as the gastrointestinal tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this letter we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 {\\mu}m. Images collected from ex vivo, in vitro and in vivo samples using the device are also presented. The compact and cost-effective smartphone microendoscope may be envisaged as a powerful tool for detecting pre-cancerous lesions of internal organs in low and middle income countries.

  3. The future of high resolution electron microscopy

    Institute of Scientific and Technical Information of China (English)

    D Van Dyck

    2000-01-01

    The state of the art and the future in quantitative high resolution electron microscopy are discussed in the framework of parameter estimation. Reconstruction methods are then to be considered as direct methods to yield a starting structure for further refinement. With the increasing flexibility of the instruments, computer aided experimental strategy will become important.

  4. High resolution spectroscopy of planet bearing stars

    Directory of Open Access Journals (Sweden)

    M. C. Gálvez

    2007-01-01

    Full Text Available We present here the first steps of an extended spectroscopic survey in order to characterize the stellar hosts of extra-solar planets. We have selected several known stars with plan- ets and using high resolution spectroscopy, we have studied their properties.

  5. High-resolution seismic profiling on water

    OpenAIRE

    McGee, T.M.

    2000-01-01

    Herein is presented an overview of high-resolution seismic profiling on water. Included are basic concepts and terminology as well as discussions of types of sources and receivers, field practice, data recording and data processing. Emphasis is on digital single-channel profiling for engineering and environmental purposes.

  6. Compact high-resolution spectral phase shaper

    NARCIS (Netherlands)

    Postma, S.; Walle, van der P.; Offerhaus, H.L.; Hulst, van N.F.

    2005-01-01

    The design and operation of a high-resolution spectral phase shaper with a footprint of only 7×10 cm2 is presented. The liquid-crystal modulator has 4096 elements. More than 600 independent degrees of freedom can be positioned with a relative accuracy of 1 pixel. The spectral shaping of pulses fro

  7. A High-Resolution Stopwatch for Cents

    Science.gov (United States)

    Gingl, Z.; Kopasz, K.

    2011-01-01

    A very low-cost, easy-to-make stopwatch is presented to support various experiments in mechanics. The high-resolution stopwatch is based on two photodetectors connected directly to the microphone input of a sound card. Dedicated free open-source software has been developed and made available to download. The efficiency is demonstrated by a free…

  8. Compressive sensing for high resolution radar imaging

    NARCIS (Netherlands)

    Anitori, L.; Otten, M.P.G.; Hoogeboom, P.

    2010-01-01

    In this paper we present some preliminary results on the application of Compressive Sensing (CS) to high resolution radar imaging. CS is a recently developed theory which allows reconstruction of sparse signals with a number of measurements much lower than what is required by the Shannon sampling th

  9. Constructing a WISE High Resolution Galaxy Atlas

    Science.gov (United States)

    Jarrett, T. H.; Masci, F.; Tsai, C. W.; Petty, S.; Cluver, M.; Assef, Roberto J.; Benford, D.; Blain, A.; Bridge, C.; Donoso, E.; Eisenhardt, P.; Fowler, J.; Koribalski, B.; Lake, S.; Neill, James D.; Seibert, M.; Stanford, S.; Wright, E.

    2012-01-01

    After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 micron, 4.6 micron, 12 micron, and 22 micron. We have begun a dedicated WISE High Resolution Galaxy Atlas project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we summarize the deconvolution techniques used to significantly improve the spatial resolution of WISE imaging, specifically designed to study the internal anatomy of nearby galaxies. As a case study, we present results for the galaxy NGC 1566, comparing the WISE enhanced-resolution image processing to that of Spitzer, Galaxy Evolution Explorer, and ground-based imaging. This is the first paper in a two-part series; results for a larger sample of nearby galaxies are presented in the second paper.

  10. High-resolution traction force microscopy.

    Science.gov (United States)

    Plotnikov, Sergey V; Sabass, Benedikt; Schwarz, Ulrich S; Waterman, Clare M

    2014-01-01

    Cellular forces generated by the actomyosin cytoskeleton and transmitted to the extracellular matrix (ECM) through discrete, integrin-based protein assemblies, that is, focal adhesions, are critical to developmental morphogenesis and tissue homeostasis, as well as disease progression in cancer. However, quantitative mapping of these forces has been difficult since there has been no experimental technique to visualize nanonewton forces at submicrometer spatial resolution. Here, we provide detailed protocols for measuring cellular forces exerted on two-dimensional elastic substrates with a high-resolution traction force microscopy (TFM) method. We describe fabrication of polyacrylamide substrates labeled with multiple colors of fiducial markers, functionalization of the substrates with ECM proteins, setting up the experiment, and imaging procedures. In addition, we provide the theoretical background of traction reconstruction and experimental considerations important to design a high-resolution TFM experiment. We describe the implementation of a new algorithm for processing of images of fiducial markers that are taken below the surface of the substrate, which significantly improves data quality. We demonstrate the application of the algorithm and explain how to choose a regularization parameter for suppression of the measurement error. A brief discussion of different ways to visualize and analyze the results serves to illustrate possible uses of high-resolution TFM in biomedical research. © 2014 Elsevier Inc. All rights reserved.

  11. Development of a high resolution and high dispersion Thomson parabola.

    Science.gov (United States)

    Jung, D; Hörlein, R; Kiefer, D; Letzring, S; Gautier, D C; Schramm, U; Hübsch, C; Öhm, R; Albright, B J; Fernandez, J C; Habs, D; Hegelich, B M

    2011-01-01

    Here, we report on the development of a novel high resolution and high dispersion Thomson parabola for simultaneously resolving protons and low-Z ions of more than 100 MeV/nucleon necessary to explore novel laser ion acceleration schemes. High electric and magnetic fields enable energy resolutions of ΔE∕E parabola for ion energies of more than 30 MeV/nucleon.

  12. Comparison of T1-weighted 2D TSE, 3D SPGR, and two-point 3D Dixon MRI for automated segmentation of visceral adipose tissue at 3 Tesla.

    Science.gov (United States)

    Fallah, Faezeh; Machann, Jürgen; Martirosian, Petros; Bamberg, Fabian; Schick, Fritz; Yang, Bin

    2017-04-01

    To evaluate and compare conventional T1-weighted 2D turbo spin echo (TSE), T1-weighted 3D volumetric interpolated breath-hold examination (VIBE), and two-point 3D Dixon-VIBE sequences for automatic segmentation of visceral adipose tissue (VAT) volume at 3 Tesla by measuring and compensating for errors arising from intensity nonuniformity (INU) and partial volume effects (PVE). The body trunks of 28 volunteers with body mass index values ranging from 18 to 41.2 kg/m(2) (30.02 ± 6.63 kg/m(2)) were scanned at 3 Tesla using three imaging techniques. Automatic methods were applied to reduce INU and PVE and to segment VAT. The automatically segmented VAT volumes obtained from all acquisitions were then statistically and objectively evaluated against the manually segmented (reference) VAT volumes. Comparing the reference volumes with the VAT volumes automatically segmented over the uncorrected images showed that INU led to an average relative volume difference of -59.22 ± 11.59, 2.21 ± 47.04, and -43.05 ± 5.01 % for the TSE, VIBE, and Dixon images, respectively, while PVE led to average differences of -34.85 ± 19.85, -15.13 ± 11.04, and -33.79 ± 20.38 %. After signal correction, differences of -2.72 ± 6.60, 34.02 ± 36.99, and -2.23 ± 7.58 % were obtained between the reference and the automatically segmented volumes. A paired-sample two-tailed t test revealed no significant difference between the reference and automatically segmented VAT volumes of the corrected TSE (p = 0.614) and Dixon (p = 0.969) images, but showed a significant VAT overestimation using the corrected VIBE images. Under similar imaging conditions and spatial resolution, automatically segmented VAT volumes obtained from the corrected TSE and Dixon images agreed with each other and with the reference volumes. These results demonstrate the efficacy of the signal correction methods and the similar accuracy of TSE and Dixon imaging for automatic volumetry of VAT at 3 Tesla.

  13. High resolution 3D nonlinear integrated inversion

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Xuben; Li Zhirong; Li Qiong; Li Zhengwen

    2009-01-01

    The high resolution 3D nonlinear integrated inversion method is based on nonlinear theory. Under layer control, the log data from several wells (or all wells) in the study area and seismic trace data adjacent to the wells are input to a network with multiple inputs and outputs and are integratedly trained to obtain an adaptive weight function of the entire study area. Integrated nonlinear mapping relationships are built and updated by the lateral and vertical geologic variations of the reservoirs. Therefore, the inversion process and its inversion results can be constrained and controlled and a stable seismic inversion section with high resolution with velocity inversion, impedance inversion, and density inversion sections, can be gained. Good geologic effects have been obtained in model computation tests and real data processing, which verified that this method has high precision, good practicality, and can be used for quantitative reservoir analysis.

  14. Progress toward high resolution EUV spectroscopy

    Science.gov (United States)

    Korendyke, C.; Doschek, G. A.; Warren, H.; Young, P. R.; Chua, D.; Hassler, D. M.; Landi, E.; Davila, J. M.; Klimchuck, J.; Tun, S.; DeForest, C.; Mariska, J. T.; Solar C Spectroscopy Working Group; LEMUR; EUVST Development Team

    2013-07-01

    HIgh resolution EUV spectroscopy is a critical instrumental technique to understand fundamental physical processes in the high temperature solar atmosphere. Spectroscopic observations are used to measure differential emission measure, line of sight and turbulent flows, plasma densities and emission measures. Spatially resolved, spectra of these emission lines with adequate cadence will provide the necessary clues linking small scale structures with large scale, energetic solar phenomena. The necessary observations to determine underlying physical processes and to provide comprehensive temperature coverage of the solar atmosphere above the chromosphere will be obtained by the proposed EUVST instrument for Solar C. This instrument and its design will be discussed in this paper. Progress on the VEry high Resolution Imaging Spectrograph (VERIS) sounding rocket instrument presently under development at the Naval Research Laboratory will also be discussed.

  15. Superconducting High Resolution Fast-Neutron Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Hau, Ionel Dragos [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Superconducting high resolution fast-neutron calorimetric spectrometers based on 6LiF and TiB{sub 2} absorbers have been developed. These novel cryogenic spectrometers measure the temperature rise produced in exothermal (n, α) reactions with fast neutrons in 6Li and 10B-loaded materials with heat capacity C operating at temperatures T close to 0.1 K. Temperature variations on the order of 0.5 mK are measured with a Mo/Cu thin film multilayer operated in the transition region between its superconducting and its normal state. The advantage of calorimetry for high resolution spectroscopy is due to the small phonon excitation energies kBT on the order of μeV that serve as signal carriers, resulting in an energy resolution ΔE ~ (kBT2C)1/2, which can be well below 10 keV. An energy resolution of 5.5 keV has been obtained with a Mo/Cu superconducting sensor and a TiB2 absorber using thermal neutrons from a 252Cf neutron source. This resolution is sufficient to observe the effect of recoil nuclei broadening in neutron spectra, which has been related to the lifetime of the first excited state in 7Li. Fast-neutron spectra obtained with a 6Li-enriched LiF absorber show an energy resolution of 16 keV FWHM, and a response in agreement with the 6Li(n, α)3H reaction cross section and Monte Carlo simulations for energies up to several MeV. The energy resolution of order of a few keV makes this novel instrument applicable to fast-neutron transmission spectroscopy based on the unique elemental signature provided by the neutron absorption and scattering resonances. The optimization of the energy resolution based on analytical and numerical models of the detector response is discussed in the context of these applications.

  16. Diffusion-weighted imaging of breast tumours at 3 Tesla and 7 Tesla: a comparison

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, S.; Minarikova, L.; Zaric, O.; Chmelik, M.; Strasser, B.; Trattnig, S.; Bogner, W. [Medical University Vienna, MRCE, Department of Biomedical imaging and Image-Guided Therapy, Vienna (Austria); Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna (Austria); Pinker, K.; Baltzer, P.; Helbich, T. [Medical University Vienna, Division of Molecular and Gender Imaging, Department of Biomedical imaging and Image-Guided Therapy, Vienna (Austria)

    2016-05-15

    To compare bilateral diffusion-weighted MR imaging (DWI) at 3 T and 7 T in the same breast tumour patients. Twenty-eight patients were included in this IRB-approved study (mean age 56 ± 16 years). Before contrast-enhanced imaging, bilateral DWI with b = 0 and 850 s/mm{sup 2} was performed in 2:56 min (3 T) and 3:48 min (7 T), using readout-segmented echo planar imaging (rs-EPI) with a 1.4 x 1.4 mm{sup 2} (3 T)/0.9 x 0.9 mm{sup 2} (7 T) in-plane resolution. Apparent diffusion coefficients (ADC), signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were assessed. Twenty-eight lesions were detected (18 malignant, 10 benign). CNR and SNR were comparable at both field strengths (p > 0.3). Mean ADC values at 7 T were 4-22 % lower than at 3 T (p ≤ 0.03). An ADC threshold of 1.275 x 10{sup -3} mm{sup 2}/s resulted in a diagnostic specificity of 90 % at both field strengths. The sensitivity was 94 % and 100 % at 3 T and 7 T, respectively. 7-T DWI of the breast can be performed with 2.4-fold higher spatial resolution than 3 T, without significant differences in SNR if compared to 3 T. (orig.)

  17. High-Resolution US of Rheumatologic Diseases.

    Science.gov (United States)

    Taljanovic, Mihra S; Melville, David M; Gimber, Lana H; Scalcione, Luke R; Miller, Margaret D; Kwoh, C Kent; Klauser, Andrea S

    2015-01-01

    For the past 15 years, high-resolution ultrasonography (US) is being routinely and increasingly used for initial evaluation and treatment follow-up of rheumatologic diseases. This imaging technique is performed by using high-frequency linear transducers and has proved to be a powerful diagnostic tool in evaluation of articular erosions, simple and complex joint and bursal effusions, tendon sheath effusions, and synovitis, with results comparable to those of magnetic resonance imaging, excluding detection of bone marrow edema. Crystal deposition diseases including gouty arthropathy and calcium pyrophosphate deposition disease (CPPD) have characteristic appearances at US, enabling differentiation between these two diseases and from inflammatory arthropathies. Enthesopathy, which frequently accompanies psoriatic and reactive arthritis, also has a characteristic appearance at high-resolution US, distinguishing these two entities from other inflammatory and metabolic arthropathies. The presence of Doppler signal in examined joints, bursae, and tendon sheaths indicates active synovitis. Microbubble echo contrast agents augment detection of tissue vascularity and may act in the future as a drug delivery vehicle. Frequently, joint, tendon sheath, and bursal fluid aspirations and therapeutic injections are performed under US guidance. The authors describe the high-resolution US technique including gray-scale, color or power Doppler, and contrast agent-enhanced US that is used in evaluation of rheumatologic diseases of the wrist and hand and the ankle and foot in their routine clinical practice. This article demonstrates imaging findings of normal joints, rheumatoid arthritis, gouty arthritis, CPPD, psoriatic and reactive arthritis, and osteoarthritis.

  18. In vivo functional connectome of human brainstem nuclei of the ascending arousal, autonomic and motor systems by high spatial resolution 7 Tesla fMRI

    Science.gov (United States)

    Bianciardi, Marta; Toschi, Nicola; Eichner, Cornelius; Polimeni, Jonathan R.; Setsompop, Kawin; Brown, Emery N.; Hamalainen, Matti S.; Rosen, Bruce R.; Wald, Lawrence L.

    2016-01-01

    Object To map the in vivo human functional connectivity of several brainstem nuclei with the rest of the brain by using seed-based correlation of ultra-high magnetic field functional magnetic resonance imaging (fMRI) data. Materials and Methods We used the recently developed template of 11 brainstem nuclei derived from multi-contrast structural MRI at 7 Tesla as seed regions to determine their connectivity to the rest of the brain. To achieve this, we utilized the increased contrast-to-noise ratio of 7 Tesla fMRI compared to 3 Tesla and the time efficient simultaneous multi-slice imaging to cover the brain with high spatial resolution (1.1 mm-isotropic nominal resolution) while maintaining a short repetition time (2.5 s). Results The delineated Pearson’s correlation-based functional connectivity diagrams (connectomes) of 11 brainstem nuclei of the ascending arousal, motor and autonomic systems from 12 controls are presented and discussed in the context of existing histology and animal work. Conclusion Considering that the investigated brainstem nuclei play a crucial role in several vital functions, the delineated preliminary connectomes might prove useful for future in vivo research and clinical studies of human brainstem function and pathology, including disorders of consciousness, sleep disorders, autonomic disorders, Parkinson’s disease and other motor disorders. PMID:27126248

  19. In vivo functional connectome of human brainstem nuclei of the ascending arousal, autonomic, and motor systems by high spatial resolution 7-Tesla fMRI.

    Science.gov (United States)

    Bianciardi, Marta; Toschi, Nicola; Eichner, Cornelius; Polimeni, Jonathan R; Setsompop, Kawin; Brown, Emery N; Hämäläinen, Matti S; Rosen, Bruce R; Wald, Lawrence L

    2016-06-01

    Our aim was to map the in vivo human functional connectivity of several brainstem nuclei with the rest of the brain by using seed-based correlation of ultra-high magnetic field functional magnetic resonance imaging (fMRI) data. We used the recently developed template of 11 brainstem nuclei derived from multi-contrast structural MRI at 7 Tesla as seed regions to determine their connectivity to the rest of the brain. To achieve this, we used the increased contrast-to-noise ratio of 7-Tesla fMRI compared with 3 Tesla and time-efficient simultaneous multi-slice imaging to cover the brain with high spatial resolution (1.1-mm isotropic nominal resolution) while maintaining a short repetition time (2.5 s). The delineated Pearson's correlation-based functional connectivity diagrams (connectomes) of 11 brainstem nuclei of the ascending arousal, motor, and autonomic systems from 12 controls are presented and discussed in the context of existing histology and animal work. Considering that the investigated brainstem nuclei play a crucial role in several vital functions, the delineated preliminary connectomes might prove useful for future in vivo research and clinical studies of human brainstem function and pathology, including disorders of consciousness, sleep disorders, autonomic disorders, Parkinson's disease, and other motor disorders.

  20. High-resolution flurescence spectroscopy in immunoanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Grubor, Nenad M.

    2005-05-01

    The work presented in this dissertation combines highly sensitive and selective fluorescence line-narrowing spectroscopy (FLNS) detection with various modes of immunoanalytical techniques. It has been shown that FLNS is capable of directly probing molecules immunocomplexed with antibodies, eliminating analytical ambiguities that may arise from interferences that accompany traditional immunochemical techniques. Moreover, the utilization of highly cross-reactive antibodies for highly specific analyte determination has been demonstrated. Finally, they demonstrate the first example of the spectral resolution of diastereomeric analytes based on their interaction with a cross-reactive antibody.

  1. High-resolution flurescence spectroscopy in immunoanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Grubor, Nenad M. [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    The work presented in this dissertation combines highly sensitive and selective fluorescence line-narrowing spectroscopy (FLNS) detection with various modes of immunoanalytical techniques. It has been shown that FLNS is capable of directly probing molecules immunocomplexed with antibodies, eliminating analytical ambiguities that may arise from interferences that accompany traditional immunochemical techniques. Moreover, the utilization of highly cross-reactive antibodies for highly specific analyte determination has been demonstrated. Finally, they demonstrate the first example of the spectral resolution of diastereomeric analytes based on their interaction with a cross-reactive antibody.

  2. High-resolution TOF with RPCs

    Energy Technology Data Exchange (ETDEWEB)

    Fonte, P. E-mail: fonte@lipc.fis.uc.pt; Peskov, V

    2002-01-21

    In this work, we describe some recent results concerning the application of Resistive Plate Chambers operated in avalanche mode at atmospheric pressure for high-resolution time-of-flight measurements. A combination of multiple, mechanically accurate, thin gas gaps and state-of-the-art electronics yielded an overall (detector plus electronics) timing accuracy better than 50 ps {sigma} with a detection efficiency up to 99% for MIPs. Single gap chambers were also tested in order to clarify experimentally several aspects of the mode of operation of these detectors. These results open perspectives of affordable and reliable high granularity large area TOF detectors, with an efficiency and time resolution comparable to the existing scintillator-based TOF technology but with a significantly, up to an order of magnitude, lower price per channel.

  3. Structural High-resolution Satellite Image Indexing

    OpenAIRE

    Xia, Gui-Song; YANG, WEN; Delon, Julie; Gousseau, Yann; Sun, Hong; Maître, Henri

    2010-01-01

    International audience; Satellite images with high spatial resolution raise many challenging issues in image understanding and pattern recognition. First, they allow measurement of small objects maybe up to 0.5 m, and both texture and geometrical structures emerge simultaneously. Second, objects in the same type of scenes might appear at different scales and orientations. Consequently, image indexing methods should combine the structure and texture information of images and comply with some i...

  4. Stellar Tools for High Resolution Population Synthesis

    Science.gov (United States)

    Chávez, M.; Bertone, E.; Rodríguez-Merino, L.; Buzzoni, A.

    2005-12-01

    We present preliminary results of the application of a new stellar library of high-resolution synthetic spectra (based upon ATLAS9 and SYNTHE codes developed by R. L. Kurucz) in the calculation of the ultraviolet-optical spectral energy distribution of simple stellar populations (SSPs). For this purpose, the library has been coupled with Buzzoni's population synthesis code. Part of this paper is also devoted to illustrate quantitatively the extent to which synthetic stellar libraries represent real stars.

  5. Petrous apex mucocele: high resolution CT

    Energy Technology Data Exchange (ETDEWEB)

    Memis, A. [Dept. of Radiology, Hospital of Ege Univ., Bornova, Izmir (Turkey); Memis, A. [Dept. of Radiology, Hospital of Ege Univ., Bornova, Izmir (Turkey); Alper, H. [Dept. of Radiology, Hospital of Ege Univ., Bornova, Izmir (Turkey); Calli, C. [Dept. of Radiology, Hospital of Ege Univ., Bornova, Izmir (Turkey); Ozer, H. [Dept. of Radiology, Hospital of Ege Univ., Bornova, Izmir (Turkey); Ozdamar, N. [Dept. of Neurosurgery, Hospital of Ege Univ., Bornova, Izmir (Turkey)

    1994-11-01

    Mucocele of the petrous apex is very rare, only three cases having been reported. Since this area is inaccessible to direct examination, imaging, preferably high resolution computed tomography (HR CT) is essential. We report a case showing an eroding, non enhancing mass with sharp, lobulated contours, within the petrous apex. The presence of a large air cell on the opposite side suggested a mucocele. (orig.)

  6. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1969-01-01

    High Resolution NMR: Theory and Chemical Applications focuses on the applications of nuclear magnetic resonance (NMR), as well as chemical shifts, lattices, and couplings. The book first offers information on the theory of NMR, including nuclear spin and magnetic moment, spin lattice relaxation, line widths, saturation, quantum mechanical description of NMR, and ringing. The text then ponders on instrumentation and techniques and chemical shifts. Discussions focus on the origin of chemical shifts, reference compounds, empirical correlations of chemical shifts, modulation and phase detection,

  7. High Speed and High Resolution Table-Top Nanoscale Imaging

    CERN Document Server

    Tadesse, G K; Demmler, S; HÄdrich, S; Wahyutama, I; Steinert, M; Spielmann, C; ZÜrch, M; TÜnnermann, A; Limpert, J; Rothhardt, J

    2016-01-01

    We present a table-top coherent diffraction imaging (CDI) experiment based on high-order harmonics generated at 18 nm by a high average power femtosecond fiber laser system. The high photon flux, narrow spectral bandwidth and high degree of spatial coherence allow for ultra-high sub-wavelength resolution imaging at a high numerical aperture. Our experiments demonstrate a half-pitch resolution of 13.6 nm, very close to the actual Abbe-limit of 12.4 nm, which is the highest resolution achieved from any table-top XUV or X-ray microscope. In addition, 20.5 nm resolution was achieved with only 3 sec of integration time bringing live diffraction imaging and 3D tomography on the nanoscale one step closer to reality. The current resolution is solely limited by the wavelength and the detector size. Thus, table-top nanoscopes with only a few-nm resolutions are in reach and will find applications in many areas of science and technology.

  8. High Sensitivity, High Frequency and High Time Resolution Decimetric Spectroscope

    Science.gov (United States)

    Sawant, H. S.; Rosa, R. R.

    1990-11-01

    RESUMEN. Se ha desarrollado el primer espectroscopio decimetrico latino americano operando en una banda de 100 MHz con alta resoluci6n de fre- cuencia (100 KHz) y tiempo (10 ms), alrededor de cualquier centro de frecuencia en el intervalo de 2000-200 MHz. El prop6sito de esta nota es describir investigaciones solares y no solares que se planean, progra ma de investigaci6n y la situaci6n actual de desarrollo de este espectroscopio. ABSTRACT. First Latin American Decimetric Spectroscope operating over a band of 100 MHz with high resolution in frequency (100 KHz) and time (10 ms), around any center frequency in the range of 2000-200 MHz is being developed. The purpose of this note is to describe planned solar, and non-solar, research programmes and present status of development of this spectroscope. Keq wo : INSTRUMENTS - SPECTROSCOPY

  9. High Resolution Measurement of the Glycolytic Rate

    Science.gov (United States)

    Bittner, Carla X.; Loaiza, Anitsi; Ruminot, Iván; Larenas, Valeria; Sotelo-Hitschfeld, Tamara; Gutiérrez, Robin; Córdova, Alex; Valdebenito, Rocío; Frommer, Wolf B.; Barros, L. Felipe

    2010-01-01

    The glycolytic rate is sensitive to physiological activity, hormones, stress, aging, and malignant transformation. Standard techniques to measure the glycolytic rate are based on radioactive isotopes, are not able to resolve single cells and have poor temporal resolution, limitations that hamper the study of energy metabolism in the brain and other organs. A new method is described in this article, which makes use of a recently developed FRET glucose nanosensor to measure the rate of glycolysis in single cells with high temporal resolution. Used in cultured astrocytes, the method showed for the first time that glycolysis can be activated within seconds by a combination of glutamate and K+, supporting a role for astrocytes in neurometabolic and neurovascular coupling in the brain. It was also possible to make a direct comparison of metabolism in neurons and astrocytes lying in close proximity, paving the way to a high-resolution characterization of brain energy metabolism. Single-cell glycolytic rates were also measured in fibroblasts, adipocytes, myoblasts, and tumor cells, showing higher rates for undifferentiated cells and significant metabolic heterogeneity within cell types. This method should facilitate the investigation of tissue metabolism at the single-cell level and is readily adaptable for high-throughput analysis. PMID:20890447

  10. High resolution measurement of the glycolytic rate

    Directory of Open Access Journals (Sweden)

    Carla X Bittner

    2010-09-01

    Full Text Available The glycolytic rate is sensitive to physiological activity, hormones, stress, aging and malignant transformation. Standard techniques to measure the glycolytic rate are based on radioactive isotopes, are not able to resolve single cells and have poor temporal resolution, limitations that hamper the study of energy metabolism in the brain and other organs. A new method is described in this article, which makes use of a recently-developed FRET glucose nanosensor to measure the rate of glycolysis in single cells with high temporal resolution. Used in cultured astrocytes, the method showed for the first time that glycolysis can be activated within seconds by a combination of glutamate and K+, supporting a role for astrocytes in neurometabolic and neurovascular coupling in the brain. It was also possible to make a direct comparison of metabolism in neurons and astrocytes lying in close proximity, paving the way to a high-resolution characterization of brain energy metabolism. Single-cell glycolytic rates were also measured in fibroblasts, adipocytes, myoblasts and tumor cells, showing higher rates for undifferentiated cells and significant metabolic heterogeneity within cell types. This method should facilitate the investigation of tissue metabolism at the single-cell level and is readily adaptable for high-throughput analysis.

  11. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Science.gov (United States)

    Boubela, Roland N.; Kalcher, Klaudius; Nasel, Christian; Moser, Ewald

    2014-02-01

    Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TRbrain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  12. SPIRAL2/DESIR high resolution mass separator

    Energy Technology Data Exchange (ETDEWEB)

    Kurtukian-Nieto, T., E-mail: kurtukia@cenbg.in2p3.fr [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Baartman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver B.C., V6T 2A3 (Canada); Blank, B.; Chiron, T. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Davids, C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Delalee, F. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Duval, M. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); El Abbeir, S.; Fournier, A. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Lunney, D. [CSNSM-IN2P3-CNRS, Université de Paris Sud, F-91405 Orsay (France); Méot, F. [BNL, Upton, Long Island, New York (United States); Serani, L. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Stodel, M.-H.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); and others

    2013-12-15

    DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. DESIR includes a high-resolution mass separator (HRS) with a designed resolving power m/Δm of 31,000 for a 1 π-mm-mrad beam emittance, obtained using a high-intensity beam cooling device. The proposed design consists of two 90-degree magnetic dipoles, complemented by electrostatic quadrupoles, sextupoles, and a multipole, arranged in a symmetric configuration to minimize aberrations. A detailed description of the design and results of extensive simulations are given.

  13. Moderate resolution spectrophotometry of high redshift quasars

    Science.gov (United States)

    Schneider, Donald P.; Schmidt, Maarten; Gunn, James E.

    1991-01-01

    A uniform set of photometry and high signal-to-noise moderate resolution spectroscopy of 33 quasars with redshifts larger than 3.1 is presented. The sample consists of 17 newly discovered quasars (two with redshifts in excess of 4.4) and 16 sources drawn from the literature. The objects in this sample have r magnitudes between 17.4 and 21.4; their luminosities range from -28.8 to -24.9. Three of the 33 objects are broad absorption line quasars. A number of possible high redshift damped Ly-alpha systems were found.

  14. Radiation length imaging with high resolution telescopes

    CERN Document Server

    Stolzenberg, U; Schwenker, B; Wieduwilt, P; Marinas, C; Lütticke, F

    2016-01-01

    The construction of low mass vertex detectors with a high level of system integration is of great interest for next generation collider experiments. Radiation length images with a sufficient spatial resolution can be used to measure and disentangle complex radiation length $X$/$X_0$ profiles and contribute to the understanding of vertex detector systems. Test beam experiments with multi GeV particle beams and high-resolution tracking telescopes provide an opportunity to obtain precise 2D images of the radiation length of thin planar objects. At the heart of the $X$/$X_0$ imaging is a spatially resolved measurement of the scattering angles of particles traversing the object under study. The main challenges are the alignment of the reference telescope and the calibration of its angular resolution. In order to demonstrate the capabilities of $X$/$X_0$ imaging, a test beam experiment has been conducted. The devices under test were two mechanical prototype modules of the Belle II vertex detector. A data sample of ...

  15. High Resolution Bathymetry Estimation Improvement with Single ImageSuper Resolution Algorithm Super Resolution Forests

    Science.gov (United States)

    2017-01-26

    process of the SRF algorithm, we were able to further increase the mean PSNR score of the high resolution estimated data from previously used bicubic...This meant that implementing the edited variance before the bicubic estimates were created caused the mean PSNR to increase the most, and all...interpolation (by about 1 dB). Figure 7: PSNR comparison (with mean scores) between Bicubic Interpolation and SRF Figure 7 shows the comparison between

  16. Clinical indications for high-resolution MRI diagnostics of the peripheral nervous system; Klinische Indikationen hochaufloesender MRT-Diagnostik des peripheren Nervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Godel, T. [Universitaetsklinikum Heidelberg, Abteilung fuer Neuroradiologie, Heidelberg (Germany); Weiler, M. [Universitaetsklinikum Heidelberg, Neurologische Klinik, Heidelberg (Germany)

    2017-03-15

    Peripheral neuropathies are common and diagnostically often challenging disorders. Difficulties particularly exist in lesion localization and recognition of complex spatial lesion patterns. Medical history taking, neurological examination, neurophysiological tests and nerve ultrasonography represent the gold standard in the diagnosis of peripheral nerve lesions but have known methodical limitations. The use of 3 Tesla magnetic resonance neurography (MRN) is an additional diagnostic imaging tool recently developed for the high-resolution visualization of long segments of peripheral nerves. Reasonable clinical indications for MRN are exemplarily presented. Using MRN a direct visualization and thus precise localization of focal and non-focal peripheral nerve lesions of various origins can be achieved with high spatial resolution down to the anatomical level of nerve fascicles. Using MRN large anatomical areas of the peripheral nervous system (PNS) can be covered in a single examination session, spatial nerve lesion patterns can be evaluated and the underlying causes can often be detected. The MRN is a valuable supplement to the diagnostic work-up of the PNS, especially in cases that cannot be clarified with standard diagnostic methods. Evaluation of the spatial nerve lesion pattern gives additional information on the origin of the underlying disease. Reasonable indications for MRN are the assessment of proximal nerve structures including the brachial and lumbosacral nerve plexi, the clarification of inconclusive diagnostic results, preoperative, postoperative and posttraumatic assessments, the identification of fascicular nerve lesions and the differential diagnosis of an alleged somatoform disorder. (orig.) [German] Periphere Neuropathien sind haeufige und diagnostisch mitunter anspruchsvolle Erkrankungen. Schwierigkeiten bestehen v. a. bei der Laesionslokalisation und Erkennung komplexer Laesionsmuster. Anamnese, klinisch-neurologische Untersuchung

  17. High-time Resolution Astrophysics and Pulsars

    CERN Document Server

    Shearer, Andy

    2008-01-01

    The discovery of pulsars in 1968 heralded an era where the temporal characteristics of detectors had to be reassessed. Up to this point detector integration times would normally be measured in minutes rather seconds and definitely not on sub-second time scales. At the start of the 21st century pulsar observations are still pushing the limits of detector telescope capabilities. Flux variations on times scales less than 1 nsec have been observed during giant radio pulses. Pulsar studies over the next 10 to 20 years will require instruments with time resolutions down to microseconds and below, high-quantum quantum efficiency, reasonable energy resolution and sensitive to circular and linear polarisation of stochastic signals. This chapter is review of temporally resolved optical observations of pulsars. It concludes with estimates of the observability of pulsars with both existing telescopes and into the ELT era.

  18. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Directory of Open Access Journals (Sweden)

    Roland N Boubela

    2014-02-01

    Full Text Available Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to true neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TR< 0.5s scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.. From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  19. Novel high-resolution VGA QWIP detector

    Science.gov (United States)

    Kataria, H.; Asplund, C.; Lindberg, A.; Smuk, S.; Alverbro, J.; Evans, D.; Sehlin, S.; Becanovic, S.; Tinghag, P.; Höglund, L.; Sjöström, F.; Costard, E.

    2017-02-01

    Continuing with its legacy of producing high performance infrared detectors, IRnova introduces its high resolution LWIR IDDCA (Integrated Detector Dewar Cooler assembly) based on QWIP (quantum well infrared photodetector) technology. The Focal Plane Array (FPA) has 640×512 pixels, with small (15μm) pixel pitch, and is based on the FLIRIndigo ISC0403 Readout Integrated Circuit (ROIC). The QWIP epitaxial structures are grown by metal-organic vapor phase epitaxy (MOVPE) at IRnova. Detector stability and response uniformity inherent to III/V based material will be demonstrated in terms of high performing detectors. Results showing low NETD at high frame rate will be presented. This makes it one of the first 15μm pitch QWIP based LWIR IDDCA commercially available on the market. High operability and stability of our other QWIP based products will also be shared.

  20. High-Temporal-Resolution High-Spatial-Resolution Spaceborne SAR Based on Continuously Varying PRF.

    Science.gov (United States)

    Men, Zhirong; Wang, Pengbo; Li, Chunsheng; Chen, Jie; Liu, Wei; Fang, Yue

    2017-07-25

    Synthetic Aperture Radar (SAR) is a well-established and powerful imaging technique for acquiring high-spatial-resolution images of the Earth's surface. With the development of beam steering techniques, sliding spotlight and staring spotlight modes have been employed to support high-spatial-resolution applications. In addition to this strengthened high-spatial-resolution and wide-swath capability, high-temporal-resolution (short repeat-observation interval) represents a key capability for numerous applications. However, conventional SAR systems are limited in that the same patch can only be illuminated for several seconds within a single pass. This paper considers a novel high-squint-angle system intended to acquire high-spatial-resolution spaceborne SAR images with repeat-observation intervals varying from tens of seconds to several minutes within a single pass. However, an exponentially increased range cell migration would arise and lead to a conflict between the receive window and 'blind ranges'. An efficient data acquisition technique for high-temporal-resolution, high-spatial-resolution and high-squint-angle spaceborne SAR, in which the pulse repetition frequency (PRF) is continuously varied according to the changing slant range, is presented in this paper. This technique allows echo data to remain in the receive window instead of conflicting with the transmitted pulse or nadir echo. Considering the precision of hardware, a compromise and practical strategy is also proposed. Furthermore, a detailed performance analysis of range ambiguities is provided with respect to parameters of TerraSAR-X. For strong point-like targets, the range ambiguity of this technique would be better than that of uniform PRF technique. For this innovative technique, a resampling strategy and modified imaging algorithm have been developed to handle the non-uniformly sampled echo data. Simulations are performed to validate the efficiency of the proposed technique and the associated

  1. Differences in Velopharyngeal Structure during Speech among Asians Revealed by 3-Tesla Magnetic Resonance Imaging Movie Mode

    Directory of Open Access Journals (Sweden)

    Kulthida Nunthayanon

    2015-01-01

    Full Text Available Objective. Different bony structures can affect the function of the velopharyngeal muscles. Asian populations differ morphologically, including the morphologies of their bony structures. The purpose of this study was to compare the velopharyngeal structures during speech in two Asian populations: Japanese and Thai. Methods. Ten healthy Japanese and Thai females (five each were evaluated with a 3-Tesla (3 T magnetic resonance imaging (MRI scanner while they produced vowel-consonant-vowel syllable (/asa/. A gradient-echo sequence, fast low-angle shot with segmented cine and parallel imaging technique was used to obtain sagittal images of the velopharyngeal structures. Results. MRI was carried out in real time during speech production, allowing investigations of the time-to-time changes in the velopharyngeal structures. Thai subjects had a significantly longer hard palate and produced shorter consonant than Japanese subjects. The velum of the Thai participants showed significant thickening during consonant production and their retroglossal space was significantly wider at rest, whereas the dimensional change during task performance was similar in the two populations. Conclusions. The 3 T MRI movie method can be used to investigate velopharyngeal function and diagnose velopharyngeal insufficiency. The racial differences may include differences in skeletal patterns and soft-tissue morphology that result in functional differences for the affected structures.

  2. Visual language and handwriting movement: functional magnetic resonance imaging at 3 tesla during generation of ideographic characters.

    Science.gov (United States)

    Matsuo, K; Kato, C; Tanaka, S; Sugio, T; Matsuzawa, M; Inui, T; Moriya, T; Glover, G H; Nakai, T

    2001-07-01

    A functional magnetic resonance imaging experiment at 3 tesla was performed to investigate the collaborative mechanism between visuospatial processing and motor execution in performing visual language generation tasks. Japanese Kanji, ideographic characters, were utilized to design tasks. The bilateral border portions between the inferior parietal lobule and the occipital lobe were involved during a Kanji puzzle task, which required subjects to combine several parts into a Kanji. The higher motor areas, such as the premotor areas and the pre-supplementary motor areas, were also activated bilaterally during the puzzle task. The parieto-occipital activation may be related to analysis of configuration or segmentation/integration of Kanji figures. Activation in the higher motor areas may be induced by cognitive components related to motor function to perform the visuospatial language task, such as intense reference for displayed characters and finding a proper character for puzzle solution. A collaborative mechanism in these areas may explain the effectiveness of tactile reading in letter recognition by patients with pure alexia or kinesthetic facilitation by Kanji users when recalling difficult Kanji.

  3. Inferior parietal lobule volume and schneiderian first-rank symptoms in Antipsychotic-Naive schizophrenia: A 3-Tesla MRI study

    Directory of Open Access Journals (Sweden)

    Danivas Vijay

    2009-01-01

    Full Text Available Background: As per Frith′s neuro-cognitive model, inferior parietal lobule (IPL is implicated in the pathogenesis of Schneiderian first-rank symptoms (FRS in schizophrenia. The specific role of IPL structural abnormalities in the pathogenesis of FRS is yet to be ascertained. Materials and Methods: Using 3-tesla MRI scanner, this first-time study examined antipsychotic-naοve schizophrenia patients ( n = 28 (patients with FRS [FRS +]: N = 14, M: F = 7:7; and patients without FRS [FRS-]: N = 14, M: F = 7:7 in comparison with sex-, handedness-, education- and socioeconomic status-matched healthy controls ( n = 14, M: F = 7:7. The volume of IPL was measured using a three-dimensional, interactive, semi-automated analysis, with good inter-rater reliability. Results: FRS + patients showed significant volume deficit in right IPL in comparison with healthy controls (F = 4.0; P=.028 after controlling for the potential confounding effects of age, sex and intracranial volume. Conclusions: Right IPL volume deficit in FRS+patients adds further support to the Frith′s model of FRS in schizophrenia.

  4. Fetal lung apparent diffusion coefficient measurement using diffusion-weighted MRI at 3 Tesla: Correlation with gestational age.

    Science.gov (United States)

    Afacan, Onur; Gholipour, Ali; Mulkern, Robert V; Barnewolt, Carol E; Estroff, Judy A; Connolly, Susan A; Parad, Richard B; Bairdain, Sigrid; Warfield, Simon K

    2016-12-01

    To evaluate the feasibility of using diffusion-weighted magnetic resonance imaging (DW-MRI) to assess the fetal lung apparent diffusion coefficient (ADC) at 3 Tesla (T). Seventy-one pregnant women (32 second trimester, 39 third trimester) were scanned with a twice-refocused Echo-planar diffusion-weighted imaging sequence with 6 different b-values in 3 orthogonal diffusion orientations at 3T. After each scan, a region-of-interest (ROI) mask was drawn to select a region in the fetal lung and an automated robust maximum likelihood estimation algorithm was used to compute the ADC parameter. The amount of motion in each scan was visually rated. When scans with unacceptable levels of motion were eliminated, the lung ADC values showed a strong association with gestational age (P < 0.01), increasing dramatically between 16 and 27 weeks and then achieving a plateau around 27 weeks. We show that to get reliable estimates of ADC values of fetal lungs, a multiple b-value acquisition, where motion is either corrected or considered, can be performed. J. Magn. Reson. Imaging 2016;44:1650-1655. © 2016 International Society for Magnetic Resonance in Medicine.

  5. Evaluation of Iron Deposition in the Adrenal Glands of β Thalassemia Major Patients Using 3-Tesla MRI

    Directory of Open Access Journals (Sweden)

    Guzelbey

    2016-05-01

    Full Text Available Background Beta-thalassemia major (β-TM patients need blood transfusions, which result in iron deposition. To regulate chelation therapy, iron load has to be measured. With MRI, the amount of signal loss and T2* decay time shortening are used for iron quantification. Objectives The aim was to measure adrenal iron load with T2* relaxometry using MRI, and to compare it with liver and cardiac iron and serum ferritin, and to find out whether adrenal iron could be predicted from those parameters. Patients and Methods Between October 2014 and March 2015, MRI was performed in 21 patients with β-TM, recieving blood transfusions and chelation therapy. The control group (n = 11 included healthy volunteers with no known history of adrenal, hematologic, chronic disease, and blood transfusion. Results Among patients, there was no significant correlation between plasma ferritin and adrenal T2*. Significant difference was detected among T2* values of adrenals between the patient and control groups. There was no significant correlation between adrenal gland and liver T2* in β-TM patients, moderate correlation was detected between adrenal T2* and cardiac T2*. Conclusion Adrenal iron in β-TM can be reliably measured in 3 Tesla MRI. The results highlight the absence of correlation between adrenal iron deposition both with serum ferritin and hepatic iron.

  6. A review of the safety implications of magnetic resonance imaging at field strengths of 3 Tesla and above

    Energy Technology Data Exchange (ETDEWEB)

    Crook, Neil [Alliance Medical, Iceni Centre, Warwick Technology Park, Warwick CV34 6DA (United Kingdom)], E-mail: ncrook@alliance.co.uk; Robinson, Leslie [Dept. of Diagnostic Radiography, School of Healthcare Professions, Faculty of Health and Social Care, University of Salford, Salford, Greater Manchester M6 6PU (United Kingdom)

    2009-11-15

    Rationale: Diagnostic imaging is being driven by technological developments particularly so in the field of Magnetic Resonance Imaging (MRI). Electromagnetic fields used to produce images are becoming much stronger and switched more rapidly and it is essential that safety advice remains appropriate and current. Using a systematic methodology, this review aims to identify the clinical safety implications in performing MRI at field strengths of 3 Tesla (T) and above and determine whether the current clinical safety guidelines are appropriate. Method: References were sourced from The Cochrane Library, Centre for Reviews and Dissemination Science Direct, PubMed and Google Scholar. Related websites searched included The British Institute of Radiology, Society of Radiographers, Royal College of Radiologists, The Institution of Engineering and Technology, IMRSER (Institute for Magnetic Resonance Safety, Education, and Research), MagNet (NHS PASA). References supplied in retrieved papers were also checked for potential relevance. The use of consistent search terminology and inclusion and exclusion criteria ensured quality and provided rigour to conclusions drawn. Conclusion: According to the literature retrieved, the current body of knowledge has allowed safety guidelines to be established for patient safety and these are both appropriate and valid at field strengths of 3 T.

  7. Peripheral nerve tractography in soft tissue tumors: a preliminary 3-tesla diffusion tensor magnetic resonance imaging study.

    Science.gov (United States)

    Kasprian, Gregor; Amann, Gabriele; Panotopoulos, Joannis; Schmidt, Manfred; Dominkus, Martin; Trattnig, Siegfried; Windhager, Reinhard; Prayer, Daniela; Nöbauer-Huhmann, Iris

    2015-03-01

    This diffusion tensor magnetic resonance imaging (DTI) study aimed to clarify the relationship of peripheral nerves and soft tissue tumors (STTs) in 3D to optimize subsequent treatment. Twenty-six consecutive STT patients (histologically malignant, n=10; intermediate, n=3; and benign, n=13) underwent 3-Tesla MRI using an echoplanar DTI sequence. Deterministic tractography was performed. Fractional anisotropy (FA) values were measured within peritumoral and distant regions of interest. Tractography depicted the 3D course of the sciatic (n=12), femoral (n=2), tibial (n=7), fibular (n=2), median (n=1), musculocutaneous (n=1), and ulnar (n=1) nerves in a regular (n=8 of 18, 44.4%) or thinned (n=7 of 18, 38.9%) fashion. The lowest peritumoral FA values, abrupt thinning, and/or complete discontinuity of trajectories were found in 2 cases with histologically proven tumoral nerve infiltration. DTI clarifies the 3D topography between major peripheral nerves and STTs and may be helpful in the assessment of peripheral nerve infiltration by malignant tumors. © 2014 Wiley Periodicals, Inc.

  8. Magnetization transfer contrast imaging in bovine and human cortical bone applying an ultrashort echo time sequence at 3 Tesla.

    Science.gov (United States)

    Springer, Fabian; Martirosian, Petros; Machann, Jürgen; Schwenzer, Nina F; Claussen, Claus D; Schick, Fritz

    2009-05-01

    Magnetization transfer (MT) contrast imaging reveals interactions between free water molecules and macromolecules in a variety of tissues. The introduction of ultrashort echo time (UTE) sequences to clinical whole-body MR scanners expands the possibility of MT imaging to tissues with extremely fast signal decay such as cortical bone. The aim of this study was to investigate the MT effect of bovine cortical bone in vitro on a 3 Tesla whole-body MR unit. A 3D-UTE sequence with a rectangular-shaped on-resonant excitation pulse and a Gaussian-shaped off-resonant saturation pulse for MT preparation was applied. The flip angle and off-resonance frequency of the MT pulse was systematically varied. Measurements on various samples of bovine cortical bone, agar gel, aqueous manganese chloride solutions, and solid polymeric materials (polyurethane) were performed, followed by preliminary applications on human tibial bone in vivo. Direct on-resonant saturation effects of the MT prepulses were calculated numerically by means of Bloch's equations. Corrected for direct saturation effects dry and fresh bovine cortical bone showed "true" MTR values of 0.26 and 0.21, respectively. In vivo data were obtained from three healthy subjects and showed MTR values of 0.30 +/- 0.08. In vivo studies into MT of cortical bone might have the potential to give new insights in musculoskeletal pathologies.

  9. Impact of preoperative and postoperative membranous urethral length measured by 3 Tesla magnetic resonance imaging on urinary continence recovery after robotic-assisted radical prostatectomy

    Science.gov (United States)

    Song, Wan; Kim, Chan Kyo; Park, Byung Kwan; Jeon, Hwang Gyun; Jeong, Byong Chang; Seo, Seong Il; Jeon, Seong Soo; Choi, Han Yong; Lee, Hyun Moo

    2017-01-01

    Introduction We sought to investigate the impact of preoperative and postoperative membranous urethral length (MUL) on urinary continence using 3 Tesla (3T) magnetic resonance imaging (MRI) after robotic-assisted radical prostatectomy (RARP). Methods Between 2008 and 2013, 190 men with RARP underwent preoperative and postoperative MRI. Patients who received adjuvant radiotherapy or who were lost to followup were excluded, leaving 186 patients eligible for analysis. Preoperative MUL was estimated from the prostate apex to the penile bulb, while postoperative MUL was estimated from the bladder neck to penile bulb. Patients with no pads or protection were considered to have complete continence. Logistic regression analysis was used to identify predictors associated with urinary incontinence at six and 12 months. Results Age was commonly associated with urinary incontinence at six and 12 months. In addition, diabetes mellitus (DM) was another factor associated with urinary incontinence at 12 months. When adjusting these variables, preoperative MUL ≤16 mm (95% confidence interval [CI] 1.01–1.14; p=0.022), postoperative MUL ≤14 mm (95% CI 1.16–9.80; p=0.025) and percent change of MUL >18% (95% CI 1.17–7.23; p=0.021) were significantly associated with urinary incontinence at six months. However, at 12 months, preoperative MUL ≤13.5 mm (95% CI 1.85–19.21; p=0.003) and postoperative MUL ≤13 mm (95% CI 1.24–13.84; p=0.021) had impacts on urinary incontinence, but not percent change of MUL. Conclusions Preoperative and postoperative MUL were significantly associated with urinary continence recovery after RARP. Therefore, efforts to preserve MUL are highly recommended during surgery for optimal continence outcomes after RARP. PMID:28360954

  10. Pathologic correlation of transperineal in-bore 3-Tesla magnetic resonance imaging-guided prostate biopsy samples with radical prostatectomy specimen.

    Science.gov (United States)

    Velez, Erik; Fedorov, Andriy; Tuncali, Kemal; Olubiyi, Olutayo; Allard, Christopher B; Kibel, Adam S; Tempany, Clare M

    2017-08-01

    To determine the accuracy of in-bore transperineal 3-Tesla (T) magnetic resonance (MR) imaging-guided prostate biopsies for predicting final Gleason grades in patients who subsequently underwent radical prostatectomy (RP). A retrospective review of men who underwent transperineal MR imaging-guided prostate biopsy (tpMRGB) with subsequent radical prostatectomy within 1 year was conducted from 2010 to 2015. All patients underwent a baseline 3-T multiparametric MRI (mpMRI) with endorectal coil and were selected for biopsy based on MR findings of a suspicious prostate lesion and high degree of clinical suspicion for cancer. Spearman correlation was performed to assess concordance between tpMRGB and final RP pathology among patients with and without previous transrectal ultrasound (TRUS)-guided biopsies. A total of 24 men met all eligibility requirements, with a median age of 65 years (interquartile range [IQR] 11.7). The median time from biopsy to RP was 85 days (IQR 50.5). Final pathology revealed Gleason 3 + 4 = 7 in 12 patients, 4 + 3 = 7 in 10 patients, and 4 + 4 = 8 in 2 patients. A strong correlation (ρ: +0.75, p < 0.001) between tpMRGB and RP results was observed, with Gleason scores concordant in 17 cases (71%). 16 of the 24 patients underwent prior TRUS biopsies. Subsequent tpMRGB revealed Gleason upgrading in 88% of cases, which was concordant with RP Gleason scores in 69% of cases (ρ: +0.75, p < 0.001). Final Gleason scores diagnosed by tpMRGB at 3-T correlate strongly with final RP surgical pathology. This may facilitate prostate cancer diagnosis, particularly in patients with negative or low-grade TRUS biopsy results in whom clinically significant cancer is suspected or detected on mpMRI.

  11. Integrated High Resolution Monitoring of Mediterranean vegetation

    Science.gov (United States)

    Cesaraccio, Carla; Piga, Alessandra; Ventura, Andrea; Arca, Angelo; Duce, Pierpaolo; Mereu, Simone

    2017-04-01

    The study of the vegetation features in a complex and highly vulnerable ecosystems, such as Mediterranean maquis, leads to the need of using continuous monitoring systems at high spatial and temporal resolution, for a better interpretation of the mechanisms of phenological and eco-physiological processes. Near-surface remote sensing techniques are used to quantify, at high temporal resolution, and with a certain degree of spatial integration, the seasonal variations of the surface optical and radiometric properties. In recent decades, the design and implementation of global monitoring networks involved the use of non-destructive and/or cheaper approaches such as (i) continuous surface fluxes measurement stations, (ii) phenological observation networks, and (iii) measurement of temporal and spatial variations of the vegetation spectral properties. In this work preliminary results from the ECO-SCALE (Integrated High Resolution Monitoring of Mediterranean vegetation) project are reported. The project was manly aimed to develop an integrated system for environmental monitoring based on digital photography, hyperspectral radiometry , and micrometeorological techniques during three years of experimentation (2013-2016) in a Mediterranean site of Italy (Capo Caccia, Alghero). The main results concerned the analysis of chromatic coordinates indices from digital images, to characterized the phenological patterns for typical shrubland species, determining start and duration of the growing season, and the physiological status in relation to different environmental drought conditions; then the seasonal patterns of canopy phenology, was compared to NEE (Net Ecosystem Exchange) patterns, showing similarities. However, maximum values of NEE and ER (Ecosystem respiration), and short term variation, seemed mainly tuned by inter annual pattern of meteorological variables, in particular of temperature recorded in the months preceding the vegetation green-up. Finally, green signals

  12. High-resolution phylogenetic microbial community profiling

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Esther; Coleman-Derr, Devin; Bowman, Brett; Schwientek, Patrick; Clum, Alicia; Copeland, Alex; Ciobanu, Doina; Cheng, Jan-Fang; Gies, Esther; Hallam, Steve; Tringe, Susannah; Woyke, Tanja

    2014-03-17

    The representation of bacterial and archaeal genome sequences is strongly biased towards cultivated organisms, which belong to merely four phylogenetic groups. Functional information and inter-phylum level relationships are still largely underexplored for candidate phyla, which are often referred to as microbial dark matter. Furthermore, a large portion of the 16S rRNA gene records in the GenBank database are labeled as environmental samples and unclassified, which is in part due to low read accuracy, potential chimeric sequences produced during PCR amplifications and the low resolution of short amplicons. In order to improve the phylogenetic classification of novel species and advance our knowledge of the ecosystem function of uncultivated microorganisms, high-throughput full length 16S rRNA gene sequencing methodologies with reduced biases are needed. We evaluated the performance of PacBio single-molecule real-time (SMRT) sequencing in high-resolution phylogenetic microbial community profiling. For this purpose, we compared PacBio and Illumina metagenomic shotgun and 16S rRNA gene sequencing of a mock community as well as of an environmental sample from Sakinaw Lake, British Columbia. Sakinaw Lake is known to contain a large age of microbial species from candidate phyla. Sequencing results show that community structure based on PacBio shotgun and 16S rRNA gene sequences is highly similar in both the mock and the environmental communities. Resolution power and community representation accuracy from SMRT sequencing data appeared to be independent of GC content of microbial genomes and was higher when compared to Illumina-based metagenome shotgun and 16S rRNA gene (iTag) sequences, e.g. full-length sequencing resolved all 23 OTUs in the mock community, while iTags did not resolve closely related species. SMRT sequencing hence offers various potential benefits when characterizing uncharted microbial communities.

  13. Novel high resolution tactile robotic fingertips

    DEFF Research Database (Denmark)

    Drimus, Alin; Jankovics, Vince; Gorsic, Matija

    2014-01-01

    This paper describes a novel robotic fingertip based on piezoresistive rubber that can sense pressure tactile stimuli with a high spatial resolution over curved surfaces. The working principle is based on a three-layer sandwich structure (conductive electrodes on top and bottom and piezoresistive...... with specialized data acquisition electronics that acquire 500 frames per second provides rich information regarding contact force, shape and angle for bio- inspired robotic fingertips. Furthermore, a model of estimating the force of contact based on values of the cells is proposed....

  14. Fast Backprojection Techniques for High Resolution Tomography

    CERN Document Server

    Koshev, Nikolay; Miqueles, Eduardo X

    2016-01-01

    Fast image reconstruction techniques are becoming important with the increasing number of scientific cases in high resolution micro and nano tomography. The processing of the large scale three-dimensional data demands new mathematical tools for the tomographic reconstruction task because of the big computational complexity of most current algorithms as the sizes of tomographic data grow with the development of more powerful acquisition hardware and more refined scientific needs. In the present paper we propose a new fast back-projection operator for the processing of tomographic data and compare it against other fast reconstruction techniques.

  15. Operating mode of high pressure straws with high spatial resolution

    CERN Document Server

    Davkov, K I; Peshekhonov, V D; Cholakov, V D

    2013-01-01

    The article presents results of studying the operating mode of thin-walled drift tubes (straws) at flushing it with a high-pressure gas mixture, which allowed obtaining extremely high spatial resolution for straw detectors. The results of studying the radiation ageing of straws operating in this mode are also described.

  16. Digital interface for high-resolution displays

    Science.gov (United States)

    Hermann, David J.; Gorenflo, Ronald L.

    1999-08-01

    Commercial display interfaces are currently transitioning from analog to digital. Although this transition is in the very early stages, the military needs to begin planning their own transition to digital. There are many problems with the analog interface in high-resolution display systems that are solved by changing to a digital interface. Also, display system cost can be lower with a digital interface to a high resolution display. Battelle is under contract with DARPA to develop an advanced Display Interface (ADI) to replace the analog RGB interfaces currently used in high definition workstation displays. The goal is to create a standard digital display interface for military applications that is based on emerging commercial standards. Support for military application- specific functionality is addressed, including display test and control. The main challenges to implementing a digital display interface are described, along with approaches to address the problems. Conceptual ADI architectures are described and contrasted. The current and emerging commercial standards for digital display interfaces are reviewed in detail. Finally, the tasks required to complete the ADI effort are outlined and described.

  17. Effect of slice orientation on reproducibility of fMRI motor activation at 3 Tesla.

    Science.gov (United States)

    Gustard, S; Fadili, J; Williams, E J; Hall, L D; Carpenter, T A; Brett, M; Bullmore, E T

    2001-12-01

    The effect of slice orientation on reproducibility and sensitivity of 3T fMRI activation using a motor task has been investigated in six normal volunteers. Four slice orientations were used; axial, oblique axial, coronal and sagittal. We applied analysis of variance (ANOVA) to suprathreshold voxel statistics to quantify variability in activation between orientations and between subjects. We also assessed signal detection accuracy in voxels across the whole brain by using a finite mixture model to fit receiver operating characteristic (ROC) curves to the data. Preliminary findings suggest that suprathreshold cluster characteristics demonstrate high motor reproducibility across subjects and orientations, although a significant difference between slice orientations in number of activated voxels was demonstrated in left motor cortex but not cerebellum. Subtle inter-orientation differences are highlighted in the ROC analyses, which are not obvious by ANOVA; the oblique axial slice orientation offers the highest signal detection accuracy, whereas coronal slices give the lowest.

  18. Crusta: Visualizing High-resolution Global Data

    Science.gov (United States)

    Bernardin, T. S.; Kreylos, O.; Bowles, C. J.; Cowgill, E.; Hamann, B.; Kellogg, L. H.

    2009-12-01

    Virtual globes have become indispensable tools for visualizing, understanding and presenting data from Earth and other planetary bodies. The scientific community has invested much effort into exploiting existing globes to their fullest potential by refining and adapting their capabilities to better satisfy specific needs. For example, Google Earth provides users with the ability to view hillshade images derived from airborne LiDAR data such as the 2007 Northern California GeoEarthScope data. However, because most available globes were not designed with the specific needs of geoscientists in mind, shortcomings are becoming increasingly evident in geoscience applications such as terrain visualization. In particular, earth scientists struggle to visualize digital elevation models with both high spatial resolution (0.5 - 1 square meters per sample) and large extent (>2000 square kilometers), such as those obtained with airborne LiDAR. To address the specific earth science need of real-time terrain visualization of LiDAR data, we are developing Crusta as part of a close collaboration involving earth and computer scientists. Crusta is a new virtual globe that differs from widely used globes by both providing accurate global data representation and the ability to easily visualize custom topographic and image data. As a result, Crusta enables real-time, interactive visualization of high resolution digital elevation data spanning thousands of square kilometers, such as the complete 2007 Northern California GeoEarthScope airborne LiDAR data set. To implement an accurate data representation and avoid distortion of the display at the poles, where other projections have singularities, Crusta represents the globe as a thirty-sided polyhedron. Each side of this polyhedron can be subdivided to an arbitrarily fine grid on the surface of the globe, which allows Crusta to accommodate input data of arbitrary resolution ranging from global (e.g., Blue Marble) to local (e.g., a tripod

  19. Customization of normal data base specific for 3-tesla MRI is mandatory in VSRAD analysis.

    Science.gov (United States)

    Goto, Masami; Suzuki, Yuuichi; Abe, Osamu; Hayashi, Naoto; Aoki, Shigeki; Mori, Harushi; Masumoto, Tomohiko; Watanabe, Yasushi; Satake, Yoshirou; Ino, Kenji; Yano, Keiichi; Iida, Kyouhito; Mima, Kazuo; Ohtomo, Kuni

    2008-07-01

    A voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) was used for quantitative analysis of parahippocampal atropy with 1.5-tesla (T) MRI in a voxel-wise manner. The analysis of images acquired under a different imaging condition provides an error factor that has a calculated value. Clinical application of 3T-MRI is necessary for establishing a normal data base (N-DB) specific for 3T-MRI data, which permits appropriate application of VSRAD. We established an N-DB specific for 3T-MRI for use in VSRAD. The "Z-score of the parahippocampal gyrus" was 0.79 +/- 0.32, and the N-DB of each age group did not have a big deflection when we analyzed a group of physically unimpaired persons in an N-DB specific for 3T-MRI. Therefore, we were able to confirm the validity of the customized N-DB. The "Z-score of the parahippocampal gyrus" was 1.62 +/- 0.47 for the N-DB of VSRAD. The numerical value was high for the group of physically unimpaired persons.

  20. High-resolution noncontact atomic force microscopy.

    Science.gov (United States)

    Pérez, Rubén; García, Ricardo; Schwarz, Udo

    2009-07-01

    original papers authored by many of the leading groups in the field with the goal of providing a well-balanced overview on the state-of-the-art in this rapidly evolving field. These papers, many of which are based on notable presentations given during the Madrid conference, feature highlights such as (1) the development of sophisticated force spectroscopy procedures that are able to map the complete 3D tip-sample force field on different surfaces; (2) the considerable resolution improvement of Kelvin probe force microscopy (reaching, in some cases, the atomic scale), which is accompanied by a thorough, quantitative understanding of the contrast observed; (3) the perfecting of atomic resolution imaging on insulating substrates, which helps reshape our microscopic understanding of surface properties and chemical activity of these surfaces; (4) the description of instrumental and methodological developments that pave the way to the atomic-scale characterization of magnetic and electronic properties of nanostructures, and last but not least (5) the extension of dynamic imaging modes to high-resolution operation in liquids, ultimately achieving atomic resolution. The latter developments are already having a significant impact in the highly competitive field of biological imaging under physiological conditions. This special issue of Nanotechnology would not have been possible without the highly professional support from Nina Couzin, Amy Harvey, Alex Wotherspoon and the entire Nanotechnology team at IOP Publishing. We are thankful for their help in pushing this project forward. We also thank the authors who have contributed their excellent original articles to this issue, the referees whose comments have helped make the issue an accurate portrait of this rapidly moving field, and the entire NC-AFM community that continues to drive NC-AFM to new horizons.

  1. Principles of high resolution NMR in solids

    CERN Document Server

    Mehring, Michael

    1983-01-01

    The field of Nuclear Magnetic Resonance (NMR) has developed at a fascinating pace during the last decade. It always has been an extremely valuable tool to the organic chemist by supplying molecular "finger print" spectra at the atomic level. Unfortunately the high resolution achievable in liquid solutions could not be obtained in solids and physicists and physical chemists had to live with unresolved lines open to a wealth of curve fitting procedures and a vast amount of speculations. High resolution NMR in solids seemed to be a paradoxon. Broad structure­ less lines are usually encountered when dealing with NMR in solids. Only with the recent advent of mUltiple pulse, magic angle, cross-polarization, two-dimen­ sional and multiple-quantum spectroscopy and other techniques during the last decade it became possible to resolve finer details of nuclear spin interactions in solids. I have felt that graduate students, researchers and others beginning to get involved with these techniques needed a book which trea...

  2. Limiting liability via high resolution image processing

    Energy Technology Data Exchange (ETDEWEB)

    Greenwade, L.E.; Overlin, T.K.

    1996-12-31

    The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

  3. High-Resolution Scintimammography: A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Rachel F. Brem; Joelle M. Schoonjans; Douglas A. Kieper; Stan Majewski; Steven Goodman; Cahid Civelek

    2002-07-01

    This study evaluated a novel high-resolution breast-specific gamma camera (HRBGC) for the detection of suggestive breast lesions. Methods: Fifty patients (with 58 breast lesions) for whom a scintimammogram was clinically indicated were prospectively evaluated with a general-purpose gamma camera and a novel HRBGC prototype. The results of conventional and high-resolution nuclear studies were prospectively classified as negative (normal or benign) or positive (suggestive or malignant) by 2 radiologists who were unaware of the mammographic and histologic results. All of the included lesions were confirmed by pathology. Results: There were 30 benign and 28 malignant lesions. The sensitivity for detection of breast cancer was 64.3% (18/28) with the conventional camera and 78.6% (22/28) with the HRBGC. The specificity with both systems was 93.3% (28/30). For the 18 nonpalpable lesions, sensitivity was 55.5% (10/18) and 72.2% (13/18) with the general-purpose camera and the HRBGC, respectively. For lesions 1 cm, 7 of 15 were detected with the general-purpose camera and 10 of 15 with the HRBGC. Four lesions (median size, 8.5 mm) were detected only with the HRBGC and were missed by the conventional camera. Conclusion: Evaluation of indeterminate breast lesions with an HRBGC results in improved sensitivity for the detection of cancer, with greater improvement shown for nonpalpable and 1-cm lesions.

  4. High-resolution light microscopy of nanoforms

    Science.gov (United States)

    Vodyanoy, Vitaly; Pustovyy, Oleg; Vainrub, Arnold

    2007-09-01

    We developed a high resolution light imaging system. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects are clearly visible on a calibrated microscope test slide (Vainrub et al., Optics Letters, 2006, 31, 2855). The two-point resolution increase results from a known narrowing of the central diffraction peak for the annular aperture. Better visibility and advanced contrast of the smallest features in the image are due to enhancement of high spatial frequencies in the optical transfer function. The imaging system is portable, low energy, and battery operated. It has been adapted to use in both transmitting and reflecting light. It is particularly applicable for motile nanoform systems where structure and functions can be depicted in real time. We have isolated micrometer and submicrometer particles, termed proteons, from human and animal blood. Proteons form by reversible seeded aggregation of proteins around proteon nucleating centers (PNCs). PNCs are comprised of 1-2nm metallic nanoclusters containing 40-300 atoms. Proteons are capable of spontaneous assembling into higher nanoform systems assuming structure of complicated topology. The arrangement of complex proteon system mimics the structure of a small biological cell. It has structures that imitate membrane and nucleolus or nuclei. Some of these nanoforms are motile. They interact and divide. Complex nanoform systems can spontaneously reduce to simple proteons. The physical properties of these nanoforms could shed some light on the properties of early life forms or forms at extreme conditions.

  5. Chemical shift imaging at 3 Tesla: effect of echo time on assessing bone marrow abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Del Grande, F. [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Ospedale Regionale di Lugano, Servizio di Radiologia, Lugano, TI (Switzerland); Subhawong, Ty [University of Miami Miller School of Medicine, Department of Radiology, Miami, FL (United States); Flammang, A. [Siemens Medical Solutions USA, Inc., Malvern, PA (United States); Fayad, L.M. [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States)

    2014-08-15

    Our purpose is to test the effect of varied in-phase (IP) and opposed-phase (OP) sequence order on characterizing marrow signal changes at 3T. The study was HIPAA compliant and IRB approved. Informed consent was waived. At 3T, IP and OP sequences were acquired in three patients with biopsy-proven osteosarcomas, using two methods: approach 1 (OP acquisition before IP acquisition) and approach 2 (OP after IP). Signal intensity (SI) measurements in 12 locations of biopsy-proven osteosarcoma and in six locations with normal bone marrow were performed independently by two experienced musculoskeletal radiologists. The signal intensity ratio (SIR) was measured within the marrow where there was T1 signal lower than skeletal muscle. A SIR < 20 % on the OP compared with IP imaging was considered positive for marrow replacement, while SIR > = 20 % was considered negative. Interobserver agreement was measured by the Lin concordance correlation coefficient (CCC). In 75 % (18/24) of locations within the biopsy-proven tumors, the SIR was >20 % (SI drop more than 20 % in OP compared to IP) using approach 2 and in 100 % (24/24) of the locations the SIR was <20 % (SI drop less than 20 % in OP compared to IP) using approach 1, indicating a high percentage of false-negative results by approach 2, and no false-negative results with approach 1. There was good agreement between observer measurement (CCC = 0.96). At 3T, the OP sequence should be acquired prior to the IP sequence, because susceptibility artifacts on a later-acquired OP sequence may lead to an erroneous interpretation of marrow signal abnormalities. (orig.)

  6. A 10 Kelvin 3 Tesla Magnet for Space Flight ADR Systems

    Science.gov (United States)

    Tuttle, Jim; Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Riall, Sara; Pourrahimi, Shahin

    2003-01-01

    Many future space flight missions are expected to use adiabatic demagnetization refrigerators (ADRs) to reach detector operating temperatures well below one Kelvin. The goal is to operate each ADR with a mechanical cooler as its heat sink, thus avoiding the use of liquid cryogens. Although mechanical coolers are being developed to operate at temperatures of 6 Kelvin and below, there is a large efficiency cost associated with operating them at the bottom of their temperature range. For the multi-stage ADR system being developed at Goddard Space Flight Center, the goal is to operate with a 10 Kelvin mechanical cooler heat sink. With currently available paramagnetic materials, the highest temperature ADR stage in such a system will require a magnetic field of approximately three Tesla. Thus the goal is to develop a small, lightweight three Tesla superconducting magnet for operation at 10 Kelvin. It is important that this magnet have a low current/field ratio. Because traditional NbTi magnets do not operate safely above about six Kelvin, a magnet with a higher Tc is required. The primary focus has been on Nb3Sn magnets. Since standard Nb3Sn wire must be coated with thick insulation, wound on a magnet mandrel and then reacted, standard Nb,Sn magnets are quite heavy and require high currents Superconducting Systems developed a Nb3Sn wire which can be drawn down to small diameter, reacted, coated with thin insulation and then wound on a small diameter coil form. By using this smaller wire and operating closer to the wire s critical current, it should be possible to reduce the mass and operating current of 10 Kelvin magnets. Using this "react-then-wind" technology, Superconducting Systems has produced prototype 10 Kelvin magnets. This paper describes the development and testing of these magnets and discusses the outlook for including 10 Kelvin magnets on space-flight missions.

  7. Venus gravity - A high-resolution map

    Science.gov (United States)

    Reasenberg, R. D.; Goldberg, Z. M.; Macneil, P. E.; Shapiro, I. I.

    1981-01-01

    The Doppler data from the radio tracking of the Pioneer Venus Orbiter (PVO) have been used in a two-stage analysis to develop a high-resolution map of the gravitational potential of Venus, represented by a central mass and a surface mass density. The two-stage procedure invokes a Kalman filter-smoother to determine the orbit of the spacecraft, and a stabilized linear inverter to estimate the surface mass density. The resultant gravity map is highly correlated with the topographic map derived from the PVO radar altimeter data. However, the magnitudes of the gravity variations are smaller than would be expected if the topography were uncompensated, indicating that at least partial compensation has taken place.

  8. Ultra-high resolution computed tomography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, Michael J. (Knoxville, TN); Sari-Sarraf, Hamed (Knoxville, TN); Tobin, Jr., Kenneth William (Harriman, TN); Gleason, Shaun S. (Knoxville, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

    2002-01-01

    A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

  9. Concept for a new high resolution high intensity diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Stuhr, U. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    A concept of a new time-of-flight powder-diffractometer for a thermal neutral beam tube at SINQ is presented. The design of the instrument optimises the contradictory conditions of high intensity and high resolution. The high intensity is achieved by using many neutron pulses simultaneously. By analysing the time-angle-pattern of the detected neutrons an assignment of the neutrons to a single pulse is possible. (author) 3 figs., tab., refs.

  10. An in vitro assessment of MRI issues at 3-Tesla for antimicrobial, silver-containing wound dressings.

    Science.gov (United States)

    Escher, Kirin B; Shellock, Frank G

    2012-11-01

    Although no reports of adverse events have been published to date, the presence of metallic dressing ingredients may present an magnetic resonance imaging (MRI) safety concern for patients using silver-containing wound dressings. The purpose of this in vitro study was to test magnetic field interactions (ie, translational attraction and torque), heating, artifacts, and conductivity (ie, electrical resistance) when using MRI at 3-Tesla for two (nonborder and border) silver-containing wound dressings. The results indicated the dressings displayed no magnetic field interactions (deflection angle 0˚; no torque), and in each case, MRI-related heating effects were at the same levels as the background temperature increases (ie, <1.8˚C). The dressings created extremely subtle artifacts (one-for-one relationship) on the MR images. With regard to the conductivity assessments, the average resistance values were 20 kOhm and 1.1 kOhm, respectively, for the nonborder and border wound dressings, which were acceptable levels. The findings show the two silver-containing wound dressings tested will not pose hazards or risks to patients and, thus, are considered "MR safe" according to the current labeling terminology used for medical products, and each dressing may be left in place when a patient undergoes an MRI examination. To date, only a hydrofiber silver-containing dressing has been tested for MRI safety. Because of potential variances in material characteristics, MRI test results are specific to the dressings tested and cannot be applied to other products. Future studies to define the level of silver concentration in dressings that may pose a hazard for performing an MRI are warranted.

  11. High-resolution colorimetric imaging of paintings

    Science.gov (United States)

    Martinez, Kirk; Cupitt, John; Saunders, David R.

    1993-05-01

    With the aim of providing a digital electronic replacement for conventional photography of paintings, a scanner has been constructed based on a 3000 X 2300 pel resolution camera which is moved precisely over a 1 meter square area. Successive patches are assembled to form a mosaic which covers the whole area at c. 20 pels/mm resolution, which is sufficient to resolve the surface textures, particularly craquelure. To provide high color accuracy, a set of seven broad-band interference filters are used to cover the visible spectrum. A calibration procedure based upon a least-mean-squares fit to the color of patches from a Macbeth Colorchecker chart yields an average color accuracy of better than 3 units in the CMC uniform color space. This work was mainly carried out as part of the VASARI project funded by the European Commission's ESPRIT program, involving companies and galleries from around Europe. The system is being used to record images for conservation research, for archival purposes and to assist in computer-aided learning in the field of art history. The paper will describe the overall system design, including the selection of the various hardware components and the design of controlling software. The theoretical basis for the color calibration methodology is described as well as the software for its practical implementation. The mosaic assembly procedure and some of the associated image processing routines developed are described. Preliminary results from the research will be presented.

  12. High resolution CT of temporal bone trauma

    Energy Technology Data Exchange (ETDEWEB)

    Youn, Eun Kyung [Korea General Hospital, Seoul (Korea, Republic of)

    1986-10-15

    Radiographic studies of the temporal bone following head trauma are indicated when there is cerebrospinal fluid otorrhea or rhinorrhoea, hearing loss, or facial nerve paralysis. Plain radiography displays only 17-30% of temporal bone fractures and pluridirectional tomography is both difficult to perform, particularly in the acutely ill patient, and less satisfactory for the demonstration of fine fractures. Consequently, high resolution CT is the imaging method of choice for the investigation of suspected temporal bone trauma and allows special resolution of fine bony detail comparable to that attainable by conventional tomography. Eight cases of temporal bone trauma examined at Korea General Hospital April 1985 through May 1986. The results were as follows: Seven patients (87%) suffered longitudinal fractures. In 6 patients who had purely conductive hearing loss, CT revealed various ossicular chain abnormality. In one patient who had neuro sensory hearing loss, CT demonstrated intract ossicular with a fracture nearing lateral wall of the lateral semicircular canal. In one patient who had mixed hearing loss, CT showed complex fracture.

  13. High Resolution Radar Measurements of Snow Avalanches

    Science.gov (United States)

    McElwaine, Jim; Sovilla, Betty; Vriend, Nathalie; Brennan, Paul; Ash, Matt; Keylock, Chris

    2013-04-01

    Geophysical mass flows, such as snow avalanches, are a major hazard in mountainous areas and have a significant impact on the infrastructure, economy and tourism of such regions. Obtaining a thorough understanding of the dynamics of snow avalanches is crucial for risk assessment and the design of defensive structures. However, because the underlying physics is poorly understood there are significant uncertainties concerning current models, which are poorly validated due to a lack of high resolution data. Direct observations of the denser core of a large avalanche are particularly difficult, since it is frequently obscured by the dilute powder cloud. We have developed and installed a phased array FMCW radar system that penetrates the powder cloud and directly images the dense core with a resolution of around 1 m at 50 Hz over the entire slope. We present data from recent avalanches at Vallee de la Sionne that show a wealth of internal structure and allow the tracking of individual fronts, roll waves and surges down the slope for the first time. We also show good agreement between the radar results and existing measurement systems that record data at particular points on the avalanche track.

  14. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

    Science.gov (United States)

    Weinberger, Oliver; Winter, Lukas; Dieringer, Matthias A; Els, Antje; Oezerdem, Celal; Rieger, Jan; Kuehne, Andre; Cassara, Antonino M; Pfeiffer, Harald; Wetterling, Friedrich; Niendorf, Thoralf

    2016-01-01

    The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation. Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each transmission regime flip angle distributions and blood-myocardium contrast are examined in a volunteer study of 12 subjects. The feasibility of the local transceiver RF coil array for cardiac chamber quantification at 3 Tesla is demonstrated. Our simulations and experiments demonstrate that cardiac MR at 3 Tesla using four-channel surface RF coil transmission is competitive versus current clinical CMR practice of large volume body RF coil transmission. The efficiency advantage of the 4TX/4RX setup facilitates shorter repetition times governed by local SAR limits versus body RF coil transmission at whole-body SAR limit. No statistically significant difference was found for cardiac chamber quantification derived with body RF coil versus four-channel surface RF coil transmission. Our simulation also show that the body RF coil exceeds local SAR limits by a factor of ~2 when driven at maximum applicable input power to reach the whole-body SAR limit. Pursuing local surface RF coil arrays for transmission in cardiac MR is a conceptually appealing alternative to body RF coil transmission, especially for patients with implants.

  15. Pyramidal fractal dimension for high resolution images

    Science.gov (United States)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024 ×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images.

  16. Detection of proximal caries with high-resolution and standard resolution digital radiographic systems

    NARCIS (Netherlands)

    Berkhout, W.E.R.; Verheij, H.G.C.; Syriopoulos, K.; Li, G.; Sanderink, G.C.H.; van der Stelt, P.F.

    2007-01-01

    Aims: The aim of this study was to: (1) compare the diagnostic accuracy of the high-resolution and standard resolution settings of four digital imaging systems for caries diagnosis and (2) compare the effect on the diagnostic accuracy of reducing the high-resolution image sizes to the standard

  17. Improved methods for high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.R.

    1987-04-01

    Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

  18. A new high-resolution TOF technology

    CERN Document Server

    Fonte, Paulo J R; Williams, M C S

    2000-01-01

    In the framework of the ALICE collaboration we have recently studied the performance of multigap Resistive Plate Chambers operated in avalanche mode and at atmospheric pressure for time-of-flight measurements. The detector provided an overall (detector plus electronics) timing accuracy of 120 ps sigma at an efficiency of 98% for MIPs. The chambers had 4 gas gaps of 0.3 mm, each limited by a metallised ceramic plate and a glass plate, with an active dimension of 4'4cm2. The gas mixture contained C2H2F4+5%isobutane+10%SF6. A few percent of streamer discharges, each releasing about 20 pC, was tolerated without any noticeable inconvenience. This detector opens perspectives of affordable and reliable high granularity large area TOF detectors, with an efficiency and a time resolution comparable to existing scintillator-based TOF technology but with significantly, up to an order of magnitude, lower price per channel.

  19. Capillary detectors for high resolution tracking

    CERN Document Server

    Annis, P

    1997-01-01

    We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 × 105 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented.

  20. Speleothems as high-resolution paleoflood archives

    Science.gov (United States)

    Denniston, Rhawn F.; Luetscher, Marc

    2017-08-01

    Over the last two decades, speleothems have become widely utilized records of past environmental variability, typically through their stable isotopic and trace elemental chemistry. Numerous speleothem researchers have identified evidence of flooding recorded by detrital layers trapped within speleothems, but few studies have developed paleoflood reconstructions from such samples. Because they can be precisely dated, are generally immune to post-depositional distortion or erosion, and can be tied to a fixed elevational baseline, speleothems hold enormous potential as high-resolution archives of cave floods, and thus as proxies for extreme rainfall or other hydrologic drivers of cave flooding. Here we review speleothem-based paleoflood reconstruction methods, identify potential biases and pitfalls, and suggest standard practices for future studies.

  1. High-resolution CT of otosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Dewen, Yang; Kodama, Takao; Tono, Tetsuya; Ochiai, Reiji; Kiyomizu, Kensuke; Suzuki, Yukiko; Yano, Takanori; Watanabe, Katsushi [Miyazaki Medical Coll., Kiyotake (Japan)

    1997-11-01

    High-resolution CT (HRCT) scans of thirty-two patients (60 ears) with the clinical diagnosis of fenestral otosclerosis were evaluated retrospectively. HRCT was performed with 1-mm-thick targeted sections and 1-mm (36 ears) or 0.5-mm (10 ears) intervals in the semiaxial projection. Seven patients (14 ears) underwent helical scanning with a 1-mm slice thickness and 1-mm/sec table speed. Forty-five ears (75%) were found to have one or more otospongiotic or otosclerotic foci on HRCT. In most instances (30 ears), the otospongiotic foci were found in the region of the fissula ante fenestram. No significant correlations between CT findings and air conduction threshold were observed. We found a significant relationship between lesions of the labyrinthine capsule and sensorineural hearing loss. We conclude that HRCT is a valuable modality for diagnosing otosclerosis, especially when otospongiotic focus is detected. (author)

  2. High resolution imaging detectors and applications

    CERN Document Server

    Saha, Swapan K

    2015-01-01

    Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in astronomical observations, and since the explanation of the photoelectric effect by Albert Einstein, the technology has evolved rather fast. The present-day technology has made it possible to develop large-format complementary metal oxide–semiconductor (CMOS) and charge-coupled device (CCD) array mosaics, orthogonal transfer CCDs, electron-multiplication CCDs, electron-avalanche photodiode arrays, and quantum-well infrared (IR) photon detectors. The requirements to develop artifact-free photon shot noise-limited images are higher sensitivity and quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions, and higher spectral bandwidth. This book aims to address such systems, technologies and design, evaluation and calibration, control...

  3. GRANULOMETRIC MAPS FROM HIGH RESOLUTION SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    Catherine Mering

    2011-05-01

    Full Text Available A new method of land cover mapping from satellite images using granulometric analysis is presented here. Discontinuous landscapes such as steppian bushes of semi arid regions and recently growing urban settlements are especially concerned by this study. Spatial organisations of the land cover are quantified by means of the size distribution analysis of the land cover units extracted from high resolution remotely sensed images. A granulometric map is built by automatic classification of every pixel of the image according to the granulometric density inside a sliding neighbourhood. Granulometric mapping brings some advantages over traditional thematic mapping by remote sensing by focusing on fine spatial events and small changes in one peculiar category of the landscape.

  4. High resolution CT of Meckel's cave.

    Science.gov (United States)

    Chui, M; Tucker, W; Hudson, A; Bayer, N

    1985-01-01

    High resolution CT of the parasellar region was carried out in 50 patients studied for suspected pituitary microadenoma, but who showed normal pituitary gland or microadenoma on CT. This control group of patients all showed an ellipsoid low-density area in the posterior parasellar region. Knowledge of the gross anatomy and correlation with metrizamide cisternography suggest that the low density region represents Meckel's cave, rather than just the trigeminal ganglion alone. Though there is considerable variation in the size of Meckel's cave in different patients as well as the two sides of the same patient, the rather constant ellipsoid configuration of the cave in normal subjects will aid in diagnosing small pathological lesions, thereby obviating more invasive cisternography via the transovale or lumbar route. Patients with "idiopathic" tic douloureux do not show a Meckel's cave significantly different from the control group.

  5. Georadar - high resolution geophysical electromagnetic device

    Directory of Open Access Journals (Sweden)

    Janez Stern

    1995-12-01

    Full Text Available Georadar is a high resolution geophysical electromagnetic device that was developed in the first part of the 1980's. In Slovenia it was first tested in 1991 on several objects of economicgeological, geotechnical and hydrogeologic nature.Here its usefulness in karst studied is presented. The first part of the paper deals with description of measurement procedure and methodological bases, and the second part with experience and results of case histories. Shown are radargrams from ornamental stone quarry Hotavlje, calcite mine Stahovica, Golobja jama karstcave near Divača and from highway construction site Razdrto-Čebulovica. All measurements were performed with the georadar instrument Pulse EKKO IV with a lOOMHz antenna according to the method of reflection profiling.

  6. Potential High Resolution Dosimeters For MRT

    Science.gov (United States)

    Bräuer-Krisch, E.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Brochard, T.; Kamlowski, A.; Cellere, G.; Paccagnella, A.; Siegbahn, E. A.; Prezado, Y.; Martinez-Rovira, I.; Bravin, A.; Dusseau, L.; Berkvens, P.

    2010-07-01

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow (˜25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 μm microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy/s, micron

  7. High-Resolution Movement EEG Classification

    Directory of Open Access Journals (Sweden)

    Jakub Štastný

    2007-01-01

    Full Text Available The aim of the contribution is to analyze possibilities of high-resolution movement classification using human EEG. For this purpose, a database of the EEG recorded during right-thumb and little-finger fast flexion movements of the experimental subjects was created. The statistical analysis of the EEG was done on the subject's basis instead of the commonly used grand averaging. Statistically significant differences between the EEG accompanying movements of both fingers were found, extending the results of other so far published works. The classifier based on hidden Markov models was able to distinguish between movement and resting states (classification score of 94–100%, but it was unable to recognize the type of the movement. This is caused by the large fraction of other (nonmovement related EEG activities in the recorded signals. A classification method based on advanced EEG signal denoising is being currently developed to overcome this problem.

  8. High-resolution transcriptome of human macrophages.

    Directory of Open Access Journals (Sweden)

    Marc Beyer

    Full Text Available Macrophages are dynamic cells integrating signals from their microenvironment to develop specific functional responses. Although, microarray-based transcriptional profiling has established transcriptional reprogramming as an important mechanism for signal integration and cell function of macrophages, current knowledge on transcriptional regulation of human macrophages is far from complete. To discover novel marker genes, an area of great need particularly in human macrophage biology but also to generate a much more thorough transcriptome of human M1- and M1-like macrophages, we performed RNA sequencing (RNA-seq of human macrophages. Using this approach we can now provide a high-resolution transcriptome profile of human macrophages under classical (M1-like and alternative (M2-like polarization conditions and demonstrate a dynamic range exceeding observations obtained by previous technologies, resulting in a more comprehensive understanding of the transcriptome of human macrophages. Using this approach, we identify important gene clusters so far not appreciated by standard microarray techniques. In addition, we were able to detect differential promoter usage, alternative transcription start sites, and different coding sequences for 57 gene loci in human macrophages. Moreover, this approach led to the identification of novel M1-associated (CD120b, TLR2, SLAMF7 as well as M2-associated (CD1a, CD1b, CD93, CD226 cell surface markers. Taken together, these data support that high-resolution transcriptome profiling of human macrophages by RNA-seq leads to a better understanding of macrophage function and will form the basis for a better characterization of macrophages in human health and disease.

  9. Characteristics of carotid atherosclerotic plaques of chronic lipid apheresis patients as assessed by In Vivo High-Resolution CMR - a comparative analysis

    Directory of Open Access Journals (Sweden)

    Grimm Jochen M

    2012-11-01

    Full Text Available Abstract Background Components of carotid atherosclerotic plaques can reliably be identified and quantified using high resolution in vivo 3-Tesla CMR. It is suspected that lipid apheresis therapy in addition to lowering serum lipid levels also has an influence on development and progression of atherosclerotic plaques. The purpose of this study was to evaluate the influence of chronic lipid apheresis (LA on the composition of atherosclerotic carotid plaques. Methods 32 arteries of 16 patients during chronic LA-therapy with carotid plaques and stenosis of 1–80% were matched according to degree of stenosis with 32 patients, who had recently suffered an ischemic stroke. Of these patients only the asymptomatic carotid artery was analyzed. All patients underwent black-blood 3 T CMR of the carotids using parallel imaging and dedicated surface coils. Cardiovascular risk factors were recorded. Morphology and composition of carotid plaques were evaluated. For statistical evaluation Fisher’s Exact and unpaired t-test were used. A p-value Results Patients in the LA-group were younger (63.5 vs. 73.9. years, p2, p Conclusion Results of this study suggest that, despite a severer risk profile for cardiovascular complications in LA-patients, chronic LA is associated with significantly lower lipid content in carotid plaques compared to plaques of patients without LA with similar degrees of stenosis, which is characteristic of clinically stable plaques.

  10. High-resolution downscaling for hydrological management

    Science.gov (United States)

    Ulbrich, Uwe; Rust, Henning; Meredith, Edmund; Kpogo-Nuwoklo, Komlan; Vagenas, Christos

    2017-04-01

    Hydrological modellers and water managers require high-resolution climate data to model regional hydrologies and how these may respond to future changes in the large-scale climate. The ability to successfully model such changes and, by extension, critical infrastructure planning is often impeded by a lack of suitable climate data. This typically takes the form of too-coarse data from climate models, which are not sufficiently detailed in either space or time to be able to support water management decisions and hydrological research. BINGO (Bringing INnovation in onGOing water management; ) aims to bridge the gap between the needs of hydrological modellers and planners, and the currently available range of climate data, with the overarching aim of providing adaptation strategies for climate change-related challenges. Producing the kilometre- and sub-daily-scale climate data needed by hydrologists through continuous simulations is generally computationally infeasible. To circumvent this hurdle, we adopt a two-pronged approach involving (1) selective dynamical downscaling and (2) conditional stochastic weather generators, with the former presented here. We take an event-based approach to downscaling in order to achieve the kilometre-scale input needed by hydrological modellers. Computational expenses are minimized by identifying extremal weather patterns for each BINGO research site in lower-resolution simulations and then only downscaling to the kilometre-scale (convection permitting) those events during which such patterns occur. Here we (1) outline the methodology behind the selection of the events, and (2) compare the modelled precipitation distribution and variability (preconditioned on the extremal weather patterns) with that found in observations.

  11. The high resolution neutrino calorimeter KARMEN

    Energy Technology Data Exchange (ETDEWEB)

    Drexlin, G.; Eberhard, V.; Gemmeke, H.; Giorginis, G.; Grandegger, W.; Gumbsheimer, R.; Hucker, H.; Husson, L.; Kleinfeller, J.; Maschuw, R.; Plischke, P.; Spohrer, G.; Schmidt, F.K.; Wochele, J.; Woelfle, S.; Zeitnitz, B. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Kernphysik 1 Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Experimentelle Kernphysik); Bodman, B.; Burtak, F.; Finckh, E.; Glombik, A.; Kretschmer, W.; Schilling, F.; Voetisch, D. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Physikalisches Inst.); Edgington, J.A.; Gorringe, T.; Malik, A. (Queen Mary Coll., London (UK)); Booth, N.E. (Oxford Univ. (UK)); Dodd, A.; Payne, A.G.D. (Rutherford Appleton Lab., Chilton (UK))

    1990-04-15

    KARMEN is a 56 t scintillation calorimeter designed for beam dump neutrino experiments at the neutron spallation facility ISIS of the Rutherford Appleton Laboratory. The calorimetric properties are demonstrated by cosmic muons and laser calibration. The measured energy resolution of the detector is {sigma}{sub E}/E{approx equal}11.5%/{radical}E(MeV), the position resolution {sigma}{sub x}=5 cm and the timing resolution {sigma}{sub t}{approx equal}350 ps. (orig.).

  12. High resolution image reconstruction from projection of low resolution images differing in subpixel shifts

    Science.gov (United States)

    Mareboyana, Manohar; Le Moigne, Jacqueline; Bennett, Jerome

    2016-05-01

    In this paper, we demonstrate simple algorithms that project low resolution (LR) images differing in subpixel shifts on a high resolution (HR) also called super resolution (SR) grid. The algorithms are very effective in accuracy as well as time efficiency. A number of spatial interpolation techniques using nearest neighbor, inverse-distance weighted averages, Radial Basis Functions (RBF) etc. are used in projection. For best accuracy of reconstructing SR image by a factor of two requires four LR images differing in four independent subpixel shifts. The algorithm has two steps: i) registration of low resolution images and (ii) shifting the low resolution images to align with reference image and projecting them on high resolution grid based on the shifts of each low resolution image using different interpolation techniques. Experiments are conducted by simulating low resolution images by subpixel shifts and subsampling of original high resolution image and the reconstructing the high resolution images from the simulated low resolution images. The results of accuracy of reconstruction are compared by using mean squared error measure between original high resolution image and reconstructed image. The algorithm was tested on remote sensing images and found to outperform previously proposed techniques such as Iterative Back Projection algorithm (IBP), Maximum Likelihood (ML) algorithms. The algorithms are robust and are not overly sensitive to the registration inaccuracies.

  13. High Resolution Image Reconstruction from Projection of Low Resolution Images DIffering in Subpixel Shifts

    Science.gov (United States)

    Mareboyana, Manohar; Le Moigne-Stewart, Jacqueline; Bennett, Jerome

    2016-01-01

    In this paper, we demonstrate a simple algorithm that projects low resolution (LR) images differing in subpixel shifts on a high resolution (HR) also called super resolution (SR) grid. The algorithm is very effective in accuracy as well as time efficiency. A number of spatial interpolation techniques using nearest neighbor, inverse-distance weighted averages, Radial Basis Functions (RBF) etc. used in projection yield comparable results. For best accuracy of reconstructing SR image by a factor of two requires four LR images differing in four independent subpixel shifts. The algorithm has two steps: i) registration of low resolution images and (ii) shifting the low resolution images to align with reference image and projecting them on high resolution grid based on the shifts of each low resolution image using different interpolation techniques. Experiments are conducted by simulating low resolution images by subpixel shifts and subsampling of original high resolution image and the reconstructing the high resolution images from the simulated low resolution images. The results of accuracy of reconstruction are compared by using mean squared error measure between original high resolution image and reconstructed image. The algorithm was tested on remote sensing images and found to outperform previously proposed techniques such as Iterative Back Projection algorithm (IBP), Maximum Likelihood (ML), and Maximum a posterior (MAP) algorithms. The algorithm is robust and is not overly sensitive to the registration inaccuracies.

  14. High Resolution Airborne Shallow Water Mapping

    Science.gov (United States)

    Steinbacher, F.; Pfennigbauer, M.; Aufleger, M.; Ullrich, A.

    2012-07-01

    In order to meet the requirements of the European Water Framework Directive (EU-WFD), authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim) a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length) of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river bed was achieved

  15. Logging Data High-Resolution Sequence Stratigraphy

    Institute of Scientific and Technical Information of China (English)

    Li Hongqi; Xie Yinfu; Sun Zhongchun; Luo Xingping

    2006-01-01

    The recognition and contrast of bed sets in parasequence is difficult in terrestrial basin high-resolution sequence stratigraphy. This study puts forward new methods for the boundary identification and contrast of bed sets on the basis of manifold logging data. The formation of calcareous interbeds, shale resistivity differences and the relation of reservoir resistivity to altitude are considered on the basis of log curve morphological characteristics, core observation, cast thin section, X-ray diffraction and scanning electron microscopy. The results show that the thickness of calcareous interbeds is between 0.5 m and 2 m, increasing on weathering crusts and faults. Calcareous interbeds occur at the bottom of Reservoir resistivity increases with altitude. Calcareous interbeds may be a symbol of recognition for the boundary of bed sets and isochronous contrast bed sets, and shale resistivity differences may confirm the stack relation and connectivity of bed sets. Based on this, a high-rcsolution chronostratigraphic framework of Xi-1 segment in Shinan area, Junggar basin is presented, and the connectivity of bed sets and oil-water contact is confirmed. In this chronostratigraphic framework, the growth order, stack mode and space shape of bed sets are qualitatively and quantitatively described.

  16. High resolution low frequency ultrasonic tomography.

    Science.gov (United States)

    Lasaygues, P; Lefebvre, J P; Mensah, S

    1997-10-01

    Ultrasonic reflection tomography results from a linearization of the inverse acoustic scattering problem, named the inverse Born approximation. The goal of ultrasonic reflection tomography is to obtain reflectivity images from backscattered measurements. This is a Fourier synthesis problem and the first step is to correctly cover the frequency space of the object. For this inverse problem, we use the classical algorithm of tomographic reconstruction by summation of filtered backprojections. In practice, only a limited number of views are available with our mechanical rig, typically 180, and the frequency bandwidth of the pulses is very limited, typically one octave. The resolving power of the system is them limited by the bandwidth of the pulse. Low and high frequencies can be restored by use of a deconvolution algorithm that enhances resolution. We used a deconvolution technique based on the Papoulis method. The advantage of this technique is conservation of the overall frequency information content of the signals. The enhancement procedure was tested by imaging a square aluminium rod with a cross-section less than the wavelength. In this application, the central frequency of the transducer was 250 kHz so that the central wavelength was 6 mm whereas the cross-section of the rod was 4 mm. Although the Born approximation was not theoretically valid in this case (high contrast), a good reconstruction was obtained.

  17. Automatic abundance analysis of high resolution spectra

    CERN Document Server

    Bonifacio, P; Bonifacio, Piercarlo; Caffau, Elisabetta

    2003-01-01

    We describe an automatic procedure for determining abundances from high resolution spectra. Such procedures are becoming increasingly important as large amounts of data are delivered from 8m telescopes and their high-multiplexing fiber facilities, such as FLAMES on ESO-VLT. The present procedure is specifically targeted for the analysis of spectra of giants in the Sgr dSph; however, the procedure may be, in principle, tailored to analyse stars of any type. Emphasis is placed on the algorithms and on the stability of the method; the external accuracy rests, ultimately, on the reliability of the theoretical models (model-atmospheres, synthetic spectra) used to interpret the data. Comparison of the results of the procedure with the results of a traditional analysis for 12 Sgr giants shows that abundances accurate at the level of 0.2 dex, comparable with that of traditional analysis of the same spectra, may be derived in a fast and efficient way. Such automatic procedures are not meant to replace the traditional ...

  18. Supporting observation campaigns with high resolution modeling

    Science.gov (United States)

    Klocke, Daniel; Brueck, Matthias; Voigt, Aiko

    2017-04-01

    High resolution simulation in support of measurement campaigns offers a promising and emerging way to create large-scale context for small-scale observations of clouds and precipitation processes. As these simulation include the coupling of measured small-scale processes with the circulation, they also help to integrate the research communities from modeling and observations and allow for detailed model evaluations against dedicated observations. In connection with the measurement campaign NARVAL (August 2016 and December 2013) simulations with a grid-spacing of 2.5 km for the tropical Atlantic region (9000x3300 km), with local refinement to 1.2 km for the western part of the domain, were performed using the icosahedral non-hydrostatic (ICON) general circulation model. These simulations are again used to drive large eddy resolving simulations with the same model for selected days in the high definition clouds and precipitation for advancing climate prediction (HD(CP)2) project. The simulations are presented with the focus on selected results showing the benefit for the scientific communities doing atmospheric measurements and numerical modeling of climate and weather. Additionally, an outlook will be given on how similar simulations will support the NAWDEX measurement campaign in the North Atlantic and AC3 measurement campaign in the Arctic.

  19. Resolution enhancement of low quality videos using a high-resolution frame

    NARCIS (Netherlands)

    Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

    2006-01-01

    This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of correspo

  20. Three-dimensional ultrashort echo time imaging of solid polymers on a 3-Tesla whole-body MRI scanner.

    Science.gov (United States)

    Springer, Fabian; Martirosian, Petros; Schwenzer, Nina F; Szimtenings, Michael; Kreisler, Peter; Claussen, Claus D; Schick, Fritz

    2008-11-01

    With the introduction of ultrashort echo time (UTE) sequences solid polymeric materials might become visible on clinical whole-body magnetic resonance (MR) scanners. The aim of this study was to characterize solid polymeric materials typically used for instruments in magnetic resonance guided interventions and implants. Relaxation behavior and signal yield were evaluated on a 3-Tesla whole-body MR unit. Nine different commonly used solid polymeric materials were investigated by means of a 3-dimensional (3D) UTE sequence with radial k-space sampling. The investigated polymeric samples with cylindrical shape (length, 150 mm; diameter, 30 mm) were placed in a commercial 8-channel knee coil. For assessment of transverse signal decay (T2*) images with variable echo times (TE) ranging from 0.07 milliseconds to 4.87 milliseconds were recorded. Spin-lattice relaxation time (T1) was calculated for all MR visible polymers with transverse relaxation times higher than T2* = 300 mus using an adapted method applying variable flip angles. Signal-to-noise ratio (SNR) was calculated at the shortest achievable echo time (TE = 0.07 milliseconds) for standardized sequence parameters. All relaxation times and SNR data are given as arithmetic mean values with standard deviations derived from 5 axially oriented slices placed around the isocenter of the coil and magnet. Six of the 9 investigated solid polymers were visible at TE = 0.07 milliseconds. Visible solid polymers showed markedly different SNR values, ie, polyethylene SNR = 1146 +/- 41, polypropylene SNR = 60 +/- 6. Nearly mono-exponential echo time dependent signal decay was observed: Transverse relaxation times differed from T2*=36 +/- 5 mus for polycarbonate to T2*=792 +/- 7 mus for polyvinylchloride (PVC). Two of the investigated solid polymers were applicable to T1 relaxation time calculation. Polyurethane had a spin-lattice relaxation time of T1 = 172 +/- 1 milliseconds, whereas PVC had T1 = 262 +/- 7 milliseconds

  1. The High Time Resolution Radio Sky

    Science.gov (United States)

    Thornton, D.

    2013-11-01

    Pulsars are laboratories for extreme physics unachievable on Earth. As individual sources and possible orbital companions can be used to study magnetospheric, emission, and superfluid physics, general relativistic effects, and stellar and binary evolution. As populations they exhibit a wide range of sub-types, with parameters varying by many orders of magnitude signifying fundamental differences in their evolutionary history and potential uses. There are currently around 2200 known pulsars in the Milky Way, the Magellanic clouds, and globular clusters, most of which have been discovered with radio survey observations. These observations, as well as being suitable for detecting the repeating signals from pulsars, are well suited for identifying other transient astronomical radio bursts that last just a few milliseconds that either singular in nature, or rarely repeating. Prior to the work of this thesis non-repeating radio transients at extragalactic distances had possibly been discovered, however with just one example status a real astronomical sources was in doubt. Finding more of these sources was a vital to proving they were real and to open up the universe for millisecond-duration radio astronomy. The High Time Resolution Universe survey uses the multibeam receiver on the 64-m Parkes radio telescope to search the whole visible sky for pulsars and transients. The temporal and spectral resolution of the receiver and the digital back-end enable the detection of relatively faint, and distant radio sources. From the Parkes telescope a large portion of the Galactic plane can be seen, a rich hunting ground for radio pulsars of all types, while previously poorly surveyed regions away from the Galactic plane are also covered. I have made a number of pulsar discoveries in the survey, including some rare systems. These include PSR J1226-6208, a possible double neutron star system in a remarkably circular orbit, PSR J1431-471 which is being eclipsed by its companion with

  2. AIRBORNE HIGH-RESOLUTION DIGITAL IMAGING SYSTEM

    Directory of Open Access Journals (Sweden)

    Prado-Molina, J.

    2006-04-01

    Full Text Available A low-cost airborne digital imaging system capable to perform aerial surveys with small-format cameras isintroduced. The equipment is intended to obtain high-resolution multispectral digital photographs constituting so aviable alternative to conventional aerial photography and satellite imagery. Monitoring software handles all theprocedures involved in image acquisition, including flight planning, real-time graphics for aircraft position updatingin a mobile map, and supervises the main variables engaged in the imaging process. This software also creates fileswith the geographical position of the central point of every image, and the flight path followed by the aircraftduring the entire survey. The cameras are mounted on a three-axis stabilized platform. A set of inertial sensorsdetermines platform's deviations independently from the aircraft and an automatic control system keeps thecameras at a continuous nadir pointing and heading, with a precision better than ± 1 arc-degree in three-axis. Thecontrol system is also in charge of saving the platform’s orientation angles when the monitoring software triggersthe camera. These external orientation parameters, together with a procedure for camera calibration give theessential elements for image orthocorrection. Orthomosaics are constructed using commercial GIS software.This system demonstrates the feasibility of large area coverage in a practical and economical way using smallformatcameras. Monitoring and automatization reduce the work while increasing the quality and the amount ofuseful images.

  3. High spatial resolution probes for neurobiology applications

    Science.gov (United States)

    Gunning, D. E.; Kenney, C. J.; Litke, A. M.; Mathieson, K.

    2009-06-01

    Position-sensitive biological neural networks, such as the brain and the retina, require position-sensitive detection methods to identify, map and study their behavior. Traditionally, planar microelectrodes have been employed to record the cell's electrical activity with device limitations arising from the electrode's 2-D nature. Described here is the development and characterization of an array of electrically conductive micro-needles aimed at addressing the limitations of planar electrodes. The capability of this array to penetrate neural tissue improves the electrode-cell electrical interface and allows more complicated 3-D networks of neurons, such as those found in brain slices, to be studied. State-of-the-art semiconductor fabrication techniques were used to etch and passivate conformally the metal coat and fill high aspect ratio holes in silicon. These are subsequently transformed into needles with conductive tips. This process has enabled the fabrication of arrays of unprecedented dimensions: 61 hexagonally close-packed electrodes, ˜200 μm tall with 60 μm spacing. Electroplating the tungsten tips with platinum ensure suitable impedance values (˜600 kΩ at 1 kHz) for the recording of neuronal signals. Without compromising spatial resolution of the neuronal recordings, this array adds a new and exciting dimension to the study of biological neural networks.

  4. High Spectral Resolution Lidar (HSRL) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2016-04-01

    High Spectral Resolution Lidar (HSRL) systems provide vertical profiles of optical depth, backscatter cross-section, depolarization, and backscatter phase function. All HSRL measurements are absolutely calibrated by reference to molecular scattering, which is measured at each point in the lidar profile. Like the Raman lidar but unlike simple backscatter lidars such as the micropulse lidar, the HSRL can measure backscatter cross-sections and optical depths without prior assumptions about the scattering properties of the atmosphere. The depolarization observations also allow robust discrimination between ice and water clouds. In addition, rigorous error estimates can be computed for all measurements. A very narrow, angular field of view reduces multiple scattering contributions. The small field of view, coupled with a narrow optical bandwidth, nearly eliminates noise due to scattered sunlight. There are two operational U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility HSRL systems, one at the Barrow North Slope of Alaska (NSA) site and the other in the second ARM Mobile Facility (AMF2) collection of instrumentation.

  5. Holographic high-resolution endoscopic image recording

    Science.gov (United States)

    Bjelkhagen, Hans I.

    1991-03-01

    Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help

  6. High-resolution imaging using endoscopic holography

    Science.gov (United States)

    Bjelkhagen, Hans I.

    1990-08-01

    Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help to their control. 1.

  7. DUACS: Toward High Resolution Sea Level Products

    Science.gov (United States)

    Faugere, Y.; Gerald, D.; Ubelmann, C.; Claire, D.; Pujol, M. I.; Antoine, D.; Desjonqueres, J. D.; Picot, N.

    2016-12-01

    The DUACS system produces, as part of the CNES/SALP project, and the Copernicus Marine Environment and Monitoring Service, high quality multimission altimetry Sea Level products for oceanographic applications, climate forecasting centers, geophysic and biology communities... These products consist in directly usable and easy to manipulate Level 3 (along-track cross-calibrated SLA) and Level 4 products (multiple sensors merged as maps or time series) and are available in global and regional version (Mediterranean Sea, Arctic, European Shelves …).The quality of the products is today limited by the altimeter technology "Low Resolution Mode" (LRM), and the lack of available observations. The launch of 2 new satellites in 2016, Jason-3 and Sentinel-3A, opens new perspectives. Using the global Synthetic Aperture Radar mode (SARM) coverage of S3A and optimizing the LRM altimeter processing (retracking, editing, ...) will allow us to fully exploit the fine-scale content of the altimetric missions. Thanks to this increase of real time altimetry observations we will also be able to improve Level-4 products by combining these new Level-3 products and new mapping methodology, such as dynamic interpolation. Finally these improvements will benefit to downstream products : geostrophic currents, Lagrangian products, eddy atlas… Overcoming all these challenges will provide major upgrades of Sea Level products to better fulfill user needs.

  8. Laser wavelength comparison by high resolution interferometry.

    Science.gov (United States)

    Layer, H P; Deslattes, R D; Schweitzer, W G

    1976-03-01

    High resolution interferometry has been used to determine the wavelength ratio between two molecularly stabilized He-Ne lasers, one locked to a methane absorption at 3.39 microm and the other locked to the k peak of (129)I(2) at 633 nm. An optical beat frequency technique gave fractional orders while a microwave sideband method yielded the integer parts. Conventional (third derivative) peak seeking servoes stabilized both laser and cavity lengths. Reproducibility of the electronic control system and optics was a few parts in 10(12), while systematic errors associated with curvature of the cavity mirrors limited the accuracy of the wavelength ratio measurement to 2 parts in 10(10). The measured wavelength ratio of the methane stabilized He-Ne laser at 3.39 microm [P(7) line, nu(3) band] to the (129)I(2) (k peak) stabilized He-Ne laser at 633 nm was 5.359 049 260 6 (0.000 2 ppm). This ratio agrees with that calculated from the (lower accuracy) results of earlier wavelength measurements made relative to the (86)Kr standard. Its higher accuracy thus permits a provisional extension of the frequency scale based on the cesium oscillator into the visible spectrum.

  9. High-resolution ophthalmic imaging system

    Science.gov (United States)

    Olivier, Scot S.; Carrano, Carmen J.

    2007-12-04

    A system for providing an improved resolution retina image comprising an imaging camera for capturing a retina image and a computer system operatively connected to the imaging camera, the computer producing short exposures of the retina image and providing speckle processing of the short exposures to provide the improved resolution retina image. The system comprises the steps of capturing a retina image, producing short exposures of the retina image, and speckle processing the short exposures of the retina image to provide the improved resolution retina image.

  10. The High Resolution IRAS Galaxy Atlas

    CERN Document Server

    Cao, Y; Prince, T A; Beichman, C A; Cao, Yu; Terebey, Susan; Prince, Thomas A.; Beichman, Charles A.

    1997-01-01

    An atlas of the Galactic plane (-4.7 deg < b < 4.7 deg) plus the molecular clouds in Orion, Rho Oph, and Taurus-Auriga has been produced at 60 and 100 micron from IRAS data. The Atlas consists of resolution-enhanced coadded images having 1 arcmin -- 2 arcmin resolution as well as coadded images at the native IRAS resolution. The IRAS Galaxy Atlas, together with the DRAO HI line / 21 cm continuum and FCRAO CO (1-0) line Galactic plane surveys, both with similar (approx. 1 arcmin) resolution, provide a powerful venue for studying the interstellar medium, star formation and large scale structure in our Galaxy. This paper documents the production and characteristics of the Atlas.

  11. Cryogenic phased-array for high resolution magnetic resonance imaging (MRI); assessment of clinical and research applications

    Science.gov (United States)

    Ip, Flora S.

    Magnetic Resonance (MR) imaging is one of the most powerful tools in diagnostic medicine for soft tissue imaging. Image acquisition techniques and hardware receivers are very important in achieving high contrast and high resolution MR images. An aim of this dissertation is to design single and multi-element room and cryogenic temperature arrays and make assessments of their signal-to-noise ratio (SNR) and SNR gain. In this dissertation, four sets of MR receiver coils are built. They are the receiver-only cryo-coils that are not commercially available. A tuning and matching circuit is attached to each coil. The tuning and matching circuits are simple; however, each device component has to operate at a high magnetic field and cryogenic temperature environment. Remote DC bias of the varactor controls the tuning and matching outside the scanner room. Active detuning of the resonator is done by two p-i-n junction (PIN) diodes. Cooling of the receiver is done by a customized liquid nitrogen cryostat. The first application is to build a 3-Tesla 2x1 horseshoe counter-rotating current (CRC) cryogenic array to image the tibia in a human body. With significant increase in SNR, the surface coil should deliver high contrast and resolution images that can show the trabecular bone and bone marrow structure. This structural image will be used to model the mechanical strength of the bone as well as bone density and chance of fracture. The planar CRC is a unique design of this surface array. The second application is to modify the coil design to 7-Tesla to study the growth of infant rhesus monkey eyes. Fast scan MR images of the infant monkey heads are taken for monitoring shapes of their eyeballs. The monkeys are induced with shortsightedness by eye lenses, and they are scanned periodically to get images of their eyeballs. The field-of-view (FOV) of these images is about five centimeters and the area of interest is two centimeters deep from the surface. Because of these reasons

  12. High resolution fire risk mapping in Italy

    Science.gov (United States)

    Fiorucci, Paolo; Biondi, Guido; Campo, Lorenzo; D'Andrea, Mirko

    2014-05-01

    extinguishing actions, leaving more resources to improve safety in areas at risk. With the availability of fire perimeters mapped over a period spanning from 5 to 10 years, depending by the region, a procedure was defined in order to assess areas at risk with high spatial resolution (900 m2) based on objective criteria by observing past fire events. The availability of fire perimeters combined with a detailed knowledge of topography and land cover allowed to understand which are the main features involved in forest fire occurrences and their behaviour. The seasonality of the fire regime was also considered, partitioning the analysis in two macro season (November- April and May- October). In addition, the total precipitation obtained from the interpolation of 30 years-long time series from 460 raingauges and the average air temperature obtained downscaling 30 years ERA-INTERIM data series were considered. About 48000 fire perimeters which burnt about 5500 km2 were considered in the analysis. The analysis has been carried out at 30 m spatial resolution. Some important considerations relating to climate and the territorial features that characterize the fire regime at national level contribute to better understand the forest fire phenomena. These results allow to define new strategies for forest fire prevention and management extensible to other geographical areas.

  13. Super-Resolution Reconstruction of High-Resolution Satellite ZY-3 TLC Images.

    Science.gov (United States)

    Li, Lin; Wang, Wei; Luo, Heng; Ying, Shen

    2017-05-07

    Super-resolution (SR) image reconstruction is a technique used to recover a high-resolution image using the cumulative information provided by several low-resolution images. With the help of SR techniques, satellite remotely sensed images can be combined to achieve a higher-resolution image, which is especially useful for a two- or three-line camera satellite, e.g., the ZY-3 high-resolution Three Line Camera (TLC) satellite. In this paper, we introduce the application of the SR reconstruction method, including motion estimation and the robust super-resolution technique, to ZY-3 TLC images. The results show that SR reconstruction can significantly improve both the resolution and image quality of ZY-3 TLC images.

  14. Large Scale, High Resolution, Mantle Dynamics Modeling

    Science.gov (United States)

    Geenen, T.; Berg, A. V.; Spakman, W.

    2007-12-01

    To model the geodynamic evolution of plate convergence, subduction and collision and to allow for a connection to various types of observational data, geophysical, geodetical and geological, we developed a 4D (space-time) numerical mantle convection code. The model is based on a spherical 3D Eulerian fem model, with quadratic elements, on top of which we constructed a 3D Lagrangian particle in cell(PIC) method. We use the PIC method to transport material properties and to incorporate a viscoelastic rheology. Since capturing small scale processes associated with localization phenomena require a high resolution, we spend a considerable effort on implementing solvers suitable to solve for models with over 100 million degrees of freedom. We implemented Additive Schwartz type ILU based methods in combination with a Krylov solver, GMRES. However we found that for problems with over 500 thousend degrees of freedom the convergence of the solver degraded severely. This observation is known from the literature [Saad, 2003] and results from the local character of the ILU preconditioner resulting in a poor approximation of the inverse of A for large A. The size of A for which ILU is no longer usable depends on the condition of A and on the amount of fill in allowed for the ILU preconditioner. We found that for our problems with over 5×105 degrees of freedom convergence became to slow to solve the system within an acceptable amount of walltime, one minute, even when allowing for considerable amount of fill in. We also implemented MUMPS and found good scaling results for problems up to 107 degrees of freedom for up to 32 CPU¡¯s. For problems with over 100 million degrees of freedom we implemented Algebraic Multigrid type methods (AMG) from the ML library [Sala, 2006]. Since multigrid methods are most effective for single parameter problems, we rebuild our model to use the SIMPLE method in the Stokes solver [Patankar, 1980]. We present scaling results from these solvers for 3D

  15. High Resolution Pulse Compression Imaging Using Super Resolution FM-Chirp Correlation Method (SCM)

    Science.gov (United States)

    Fujiwara, M.; Okubo, K.; Tagawa, N.

    This study addresses the issue of the super-resolution pulse compression technique (PCT) for ultrasound imaging. Time resolution of multiple ultrasonic echoes using the FM-Chirp PCT is limited by the bandwidth of the sweep-frequency. That is, the resolution depends on the sharpness of auto-correlation function. We propose the Super resolution FM-Chirp correlation Method (SCM) and evaluate its performance. This method is based on the multiple signal classification (MUSIC) algorithm. Our simulations were made for the model assuming multiple signals reflected from some scatterers. We confirmed that SCM detects time delay of complicated reflected signals successfully with high resolution.

  16. Assessment of MRI issues at 3-Tesla for metallic surgical implants: findings applied to 61 additional skin closure staples and vessel ligation clips

    Science.gov (United States)

    2012-01-01

    Purpose Metallic skin closure staples and vessel ligation clips should be tested at 3-Tesla to characterize MRI issues in order to ensure patient safety. Therefore, metallic surgical implants were assessed at 3-Tesla for magnetic field interactions, MRI-related heating, and artifacts. Methods A skin closure staple (Visistat Skin Stapler, staple, Polytetrafluoroethylene, PTFE, coated 316L/316LVM stainless steel; Teleflex Medical, Durham, NC) and a vessel ligation clip (Hemoclip Traditional, stainless steel; Teleflex Medical, Durham, NC) that represented the largest metallic sizes made from materials with the highest magnetic susceptibilities (i.e., based on material information) among 61 other surgical implants (52 metallic implants, 9 nonmetallic implants) underwent evaluation for magnetic field interactions, MRI-related heating, and artifacts using standardized techniques. MRI-related heating was assessed by placing each implant in a gelled-saline-filled phantom with MRI performed using a transmit/receive RF body coil at an MR system reported, whole body averaged SAR of 2.9-W/kg for 15-min. Artifacts were characterized using T1-weighted, SE and GRE pulse sequences. Results Each surgical implant showed minor magnetic field interactions (20- and 27-degrees, which is acceptable from a safety consideration). Heating was not substantial (highest temperature change, ≤ 1.6°C). Artifacts may create issues if the area of interest is in the same area or close to the respective surgical implant. Conclusions The results demonstrated that it would be acceptable for patients with these metallic surgical implants to undergo MRI at 3-Tesla or less. Because of the materials and dimensions of the surgical implants that underwent testing, these findings pertain to 61 additional similar implants. PMID:22230200

  17. High Resolution Surface Science at Mars

    Science.gov (United States)

    Bailey, Zachary J.; Tamppari, Leslie K.; Lock, Robert E.; Sturm, Erick J.

    2013-01-01

    The proposed mission would place a 2.4 m telescope in orbit around Mars with two focal plane instruments to obtain the highest resolution images and spectral maps of the surface to date (3-10x better than current). This investigation would make major contributions to all of the Mars Program Goals: life, climate, geology and preparation for human presence.

  18. High spatial resolution LWIR hyperspectral sensor

    Science.gov (United States)

    Roberts, Carson B.; Bodkin, Andrew; Daly, James T.; Meola, Joseph

    2015-06-01

    Presented is a new hyperspectral imager design based on multiple slit scanning. This represents an innovation in the classic trade-off between speed and resolution. This LWIR design has been able to produce data-cubes at 3 times the rate of conventional single slit scan devices. The instrument has a built-in radiometric and spectral calibrator.

  19. High-speed photography of high-resolution moire patterns

    Science.gov (United States)

    Whitworth, Martin B.; Huntley, Jonathan M.; Field, John E.

    1991-04-01

    The techniques of high resolution moire photography and high speed photography have been combined to allow measurement of the in-plane components of a transient displacement field with microsecond time resolution. Specimen gratings are prepared as casts in a thin layer of epoxy resin on the surface of a specimen. These are illuminated with a flash tube and imaged onto a reference grating with a specially modified camera lens, which incorporates a slotted mask in the aperture plane. For specimen gratings of 75 lines mm1, this selects the +1 and -1 order diffracted beams, thus doubling the effective grating frequency to 150 lines mm1. The resulting real-time moire fringes are recorded with a Hadland 792 image converter camera (Imacon) at an inter-frame time of 2-5ts. The images are digitised and an automatic fringe analysis technique based on the 2-D Fourier transform method is used to extract the displacement information. The technique is illustrated by the results of an investigation into the transient deformation of composite disc specimens, impacted with rectangular metal sliders fired from a gas gun.

  20. Somatotopic organization of the medial wall of the cerebral hemispheres: a 3 Tesla fMRI study.

    Science.gov (United States)

    Mayer, A R; Zimbelman, J L; Watanabe, Y; Rao, S M

    2001-12-04

    Somatotopic organization of the human medial wall of the cerebral hemispheres was studied using functional MRI conducted at high field strength (3 T) with fine spatial resolution ( approximately 2 mm). Healthy subjects performed paced, repetitive movements of the fingers and toes. Within the supplementary motor area (SMA), two regions were identified: finger movements activated a region rostral and superior to that for toe movements. Two activation foci were also identified in the cingulate motor area: toe movements activated a region rostral and ventral to that activated by finger movements. All foci were located between the anterior and posterior commissures. Our results confirm previous human and non-human primate studies regarding the rostral-caudal organization of the SMA and CMA. The dorsal-ventral organization of the CMA, however, appears to be divergent from results derived from cortical stimulation studies conducted in non-human primates.

  1. Quantum interpolation for high-resolution sensing.

    Science.gov (United States)

    Ajoy, Ashok; Liu, Yi-Xiang; Saha, Kasturi; Marseglia, Luca; Jaskula, Jean-Christophe; Bissbort, Ulf; Cappellaro, Paola

    2017-02-28

    Recent advances in engineering and control of nanoscale quantum sensors have opened new paradigms in precision metrology. Unfortunately, hardware restrictions often limit the sensor performance. In nanoscale magnetic resonance probes, for instance, finite sampling times greatly limit the achievable sensitivity and spectral resolution. Here we introduce a technique for coherent quantum interpolation that can overcome these problems. Using a quantum sensor associated with the nitrogen vacancy center in diamond, we experimentally demonstrate that quantum interpolation can achieve spectroscopy of classical magnetic fields and individual quantum spins with orders of magnitude finer frequency resolution than conventionally possible. Not only is quantum interpolation an enabling technique to extract structural and chemical information from single biomolecules, but it can be directly applied to other quantum systems for superresolution quantum spectroscopy.

  2. High Resolution RPCs for Large TOF Systems

    CERN Document Server

    Ferreira-Marques, R; CERN. Geneva; Carolino, N; Policarpo, Armando; Fonte, P

    1999-01-01

    Here we report on a particular type of RPC that presents above 95% efficiency for minimum ionizing particles and a very sharp time resolution, below 80 ps sigma. Our 9cm2 cells, made with glass and metal electrodes that form accurately spaced gaps of a few hundred micrometers, are operated at atmospheric pressure in non-flammable gases and can be economically produced in large quantities, opening perspectives for the construction of large area timeof flight systems.

  3. Ultra-high resolution electron microscopy

    Science.gov (United States)

    Oxley, Mark P.; Lupini, Andrew R.; Pennycook, Stephen J.

    2017-02-01

    The last two decades have seen dramatic advances in the resolution of the electron microscope brought about by the successful correction of lens aberrations that previously limited resolution for most of its history. We briefly review these advances, the achievement of sub-Ångstrom resolution and the ability to identify individual atoms, their bonding configurations and even their dynamics and diffusion pathways. We then present a review of the basic physics of electron scattering, lens aberrations and their correction, and an approximate imaging theory for thin crystals which provides physical insight into the various different imaging modes. Then we proceed to describe a more exact imaging theory starting from Yoshioka’s formulation and covering full image simulation methods using Bloch waves, the multislice formulation and the frozen phonon/quantum excitation of phonons models. Delocalization of inelastic scattering has become an important limiting factor at atomic resolution. We therefore discuss this issue extensively, showing how the full-width-half-maximum is the appropriate measure for predicting image contrast, but the diameter containing 50% of the excitation is an important measure of the range of the interaction. These two measures can differ by a factor of 5, are not a simple function of binding energy, and full image simulations are required to match to experiment. The Z-dependence of annular dark field images is also discussed extensively, both for single atoms and for crystals, and we show that temporal incoherence must be included accurately if atomic species are to be identified through matching experimental intensities to simulations. Finally we mention a few promising directions for future investigation.

  4. High-quality multi-resolution volume rendering in medicine

    Institute of Scientific and Technical Information of China (English)

    XIE Kai; YANG Jie; LI Xiao-liang

    2007-01-01

    In order to perform a high-quality interactive rendering of large medical data sets on a single off-theshelf PC, a LOD selection algorithm for multi-resolution volume rendering using 3D texture mapping is presented, which uses an adaptive scheme that renders the volume in a region-of-interest at a high resolution and the volume away from this region at lower resolutions. The algorithm is based on several important criteria, and rendering is done adaptively by selecting high-resolution cells close to a center of attention and low-resolution cells away from this area. In addition, our hierarchical level-of-detail representation guarantees consistent interpolation between different resolution levels. Experiments have been applied to a number of large medical data and have produced high quality images at interactive frame rates using standard PC hardware.

  5. Using high-resolution displays for high-resolution cardiac data.

    Science.gov (United States)

    Goodyer, Christopher; Hodrien, John; Wood, Jason; Kohl, Peter; Brodlie, Ken

    2009-07-13

    The ability to perform fast, accurate, high-resolution visualization is fundamental to improving our understanding of anatomical data. As the volumes of data increase from improvements in scanning technology, the methods applied to visualization must evolve. In this paper, we address the interactive display of data from high-resolution magnetic resonance imaging scanning of a rabbit heart and subsequent histological imaging. We describe a visualization environment involving a tiled liquid crystal display panel display wall and associated software, which provides an interactive and intuitive user interface. The oView software is an OpenGL application that is written for the VR Juggler environment. This environment abstracts displays and devices away from the application itself, aiding portability between different systems, from desktop PCs to multi-tiled display walls. Portability between display walls has been demonstrated through its use on walls at the universities of both Leeds and Oxford. We discuss important factors to be considered for interactive two-dimensional display of large three-dimensional datasets, including the use of intuitive input devices and level of detail aspects.

  6. High resolution RPC's for large TOF systems

    CERN Document Server

    Fonte, Paulo J R; Pinhão, J; Carolino, N; Policarpo, Armando

    2000-01-01

    Here we report on a particular type of RPC that presents up to 99% efficiency for minimum ionizing particles and a very good time resolution, below 50 ps s for the most optimized construction. Our 9 cm2 cells, made with glass and metal electrodes that form accurately spaced gaps of a few hundred micrometers, are operated at atmospheric pressure in non-flammable gases and can be economically produced in large quantities, opening perspectives for the construction of large area time of flight systems.

  7. High resolution IVEM tomography of biological specimens

    Energy Technology Data Exchange (ETDEWEB)

    Sedat, J.W.; Agard, D.A. [Univ. of California, San Francisco, CA (United States)

    1997-02-01

    Electron tomography is a powerful tool for elucidating the three-dimensional architecture of large biological complexes and subcellular organelles. The introduction of intermediate voltage electron microscopes further extended the technique by providing the means to examine very large and non-symmetrical subcellular organelles, at resolutions beyond what would be possible using light microscopy. Recent studies using electron tomography on a variety of cellular organelles and assemblies such as centrosomes, kinetochores, and chromatin have clearly demonstrated the power of this technique for obtaining 3D structural information on non-symmetric cell components. When combined with biochemical and molecular observations, these 3D reconstructions have provided significant new insights into biological function.

  8. DSCOVR High Time Resolution Solar Wind Measurements

    Science.gov (United States)

    Szabo, Adam

    2012-01-01

    The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.

  9. Nanosecond microscopy with a high spectroscopic resolution

    CERN Document Server

    Heinrich, C; Ritsch-Marte, M; Bernet, Stefan; Heinrich, Christoph; Ritsch-Marte, Monika

    2005-01-01

    We demonstrate coherent anti-Stokes Raman scattering (CARS) microscopy in a wide-field setup with nanosecond laser pulse excitation. In contrast to confocal setups, the image of a sample can be recorded with a single pair of excitation pulses. For this purpose the excitation geometry is specially designed in order to satisfy the phase matching condition over the whole sample area. The spectral, temporal and spatial sensitivity of the method is demonstrated by imaging test samples, i.e. oil vesicles in sunflower seeds, on a nanosecond timescale. The method provides snapshot imaging in 3 nanoseconds with a spectral resolution of 25 wavenumbers (cm$^{-1}$).

  10. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  11. Towards high resolution data assimilation and ensemble forecasting

    NARCIS (Netherlands)

    Stappers, R.J.J.

    2013-01-01

    Due the increase in computational power of supercomputers the grid resolution of high resolution numerical weather prediction models is now reaching the 1 km scale. As a result, mesoscale processes related to high impact weather (such as deep convection) can now explicitly be resolved by the models.

  12. High-resolution X-ray diffraction studies of multilayers

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Hornstrup, Allan; Schnopper, H. W.

    1988-01-01

    High-resolution X-ray diffraction studies of the perfection of state-of-the-art multilayers are presented. Data were obtained using a triple-axis perfect-crystal X-ray diffractometer. Measurements reveal large-scale figure errors in the substrate. A high-resolution triple-axis set up is required...

  13. High-Speed Smart Camera with High Resolution

    Directory of Open Access Journals (Sweden)

    J. Dubois

    2007-02-01

    Full Text Available High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs, readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded processing. Two types of algorithms have been implemented. A compression algorithm, specific to high-speed imaging constraints, has been implemented. This implementation allows to reduce the large data flow (6.55 Gbps and to propose a transfer on a serial output link (USB 2.0. The second type of algorithm is dedicated to feature extraction such as edge detection, markers extraction, or image analysis, wavelet analysis, and object tracking. These image processing algorithms have been implemented into an FPGA embedded inside the camera. These implementations are low-cost in terms of hardware resources. This FPGA technology allows us to process in real time 500 images per second with a 1280×1024 resolution. This camera system is a reconfigurable platform, other image processing algorithms can be implemented.

  14. High-Speed Smart Camera with High Resolution

    Directory of Open Access Journals (Sweden)

    Mosqueron R

    2007-01-01

    Full Text Available High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs, readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded processing. Two types of algorithms have been implemented. A compression algorithm, specific to high-speed imaging constraints, has been implemented. This implementation allows to reduce the large data flow (6.55 Gbps and to propose a transfer on a serial output link (USB 2.0. The second type of algorithm is dedicated to feature extraction such as edge detection, markers extraction, or image analysis, wavelet analysis, and object tracking. These image processing algorithms have been implemented into an FPGA embedded inside the camera. These implementations are low-cost in terms of hardware resources. This FPGA technology allows us to process in real time 500 images per second with a 1280×1024 resolution. This camera system is a reconfigurable platform, other image processing algorithms can be implemented.

  15. High-Resolution Sonars: What Resolution Do We Need for Target Recognition?

    Directory of Open Access Journals (Sweden)

    Pailhas Yan

    2010-01-01

    Full Text Available Target recognition in sonar imagery has long been an active research area in the maritime domain, especially in the mine-counter measure context. Recently it has received even more attention as new sensors with increased resolution have been developed; new threats to critical maritime assets and a new paradigm for target recognition based on autonomous platforms have emerged. With the recent introduction of Synthetic Aperture Sonar systems and high-frequency sonars, sonar resolution has dramatically increased and noise levels decreased. Sonar images are distance images but at high resolution they tend to appear visually as optical images. Traditionally algorithms have been developed specifically for imaging sonars because of their limited resolution and high noise levels. With high-resolution sonars, algorithms developed in the image processing field for natural images become applicable. However, the lack of large datasets has hampered the development of such algorithms. Here we present a fast and realistic sonar simulator enabling development and evaluation of such algorithms.We develop a classifier and then analyse its performances using our simulated synthetic sonar images. Finally, we discuss sensor resolution requirements to achieve effective classification of various targets and demonstrate that with high resolution sonars target highlight analysis is the key for target recognition.

  16. MR visualization of the inner ear structures: comparison of 1.5 Tesla and 3 Tesla images

    Energy Technology Data Exchange (ETDEWEB)

    Graf, H.; Schick, F. [Tuebingen Univ. (Germany). Sektion Experimentelle Radiologie; Claussen, C.D.; Seemann, M.D. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik

    2004-01-01

    Aim of the Study: To compare high resolution MRI examinations of inner ear structures at 1.5 T and at 3 T. Method: Temporal bones were measured bilaterally in 3 healthy volunteers in a 1.5 T and in a 3 T MR-scanner using the respective one channel head coil (quadrature detection) of the manufacturer. The same steady-state gradient echo sequence (3D-CISS) was employed at a voxel size of 0.4x0.4x0.4mm{sup 3}. The signal-to-noise ratio (SNR) was determined quantitatively. Results: An SNR of 8 could be achieved for the measurements at 3 T in 7:37 min. The SNR at 3 T was, on average, a factor of 1.34 higher than that at 1.5 T despite the fact that the excitation angle had to be drastically reduced ({alpha} = 42 instead of {alpha} = 70 at 1.5 T) due to the limit of the specific absorption rate (SAR). Discussion: The MR representation of the inner ear is clearly improved at 3 T. To obtain the same SNR at 1.5 T approximately the double measuring time would be required, connected with reduced patient comfort and an increased risk for a displacement of the head during the high resolution measurement. (orig.) [German] Ziel der Studie: Vergleich der hochaufloesenden MR-Bildgebung der Innenohrstrukturen bei 1,5 T und 3 T. Methode: Es wurden jeweils beide Felsenbeine von 3 freiwilligen, gehoergesunden Probanden an einem 1,5 T und einem 3 T MR-Tomographen mit einer einkanaligen Quadratur-Kopfspule des Herstellers gemessen. An beiden Tomographen wurde dieselbe Steady-State Gradientenecho-Sequenz (3D-CISS) bei einer Voxelgroesse von 0,4x0,4x0,4mm{sup 3} verwendet. Das erhaltene Signal-Rausch-Verhaeltnis (SNR) wurde quantitativ ermittelt. Ergebnis: Ein SNR von 8 wurde fuer die Messungen bei 3 T in 7:37 min erreicht. Der SNR-Wert bei 3 T uebertraf den Wert bei 1,5 T um durchschnittlich das 1,34-fache, obwohl aufgrund der Begrenzung in der spezifischen Absorptionsrate (SAR) nur mit deutlich reduziertem Anregewinkel ({alpha} = 42 anstatt {alpha} = 70 bei 1,5 T) gearbeitet werden konnte

  17. 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.

  18. The high spectral resolution (scanning) lidar (HSRL)

    Energy Technology Data Exchange (ETDEWEB)

    Eloranta, E. [Univ. of Wisconsin, Madison, WI (United States)

    1995-09-01

    Lidars enable the spatial resolution of optical depth variation in clouds. The optical depth must be inverted from the backscatter signal, a process which is complicated by the fact that both molecular and aerosol backscatter signals are present. The HSRL has the advantage of allowing these two signals to be separated. It has a huge dynamic range, allowing optical depth retrieval for t = 0.01 to 3. Depolarization is used to determine the nature of hydrometeors present. Experiments show that water clouds must almost always be taken into account during cirrus observations. An exciting new development is the possibility of measuring effective radius via diffraction peak width and variable field-of-view measurements. 2 figs.

  19. Studying stellar populations at high spectral resolution

    CERN Document Server

    Bruzual, Gustavo A

    2007-01-01

    I describe very briefly the new libraries of empirical spectra of stars covering wide ranges of values of the atmospheric parameters Teff, log g, [Fe/H], as well as spectral type, that have become available in the recent past, among them the HNGSL, MILES, UVES-POP, ELODIE, and the IndoUS libraries. I show the results of using the IndoUS and the HNGSL libraries, as well as an atlas of theoretical model atmospheres, to build population synthesis models. These libraries are complementary in spectral resolution and wavelength coverage, and will prove extremely useful to describe spectral features expected in galaxy spectra from the NUV to the NIR. The fits to observed galaxy spectra using simple and composite stellar population models are discussed.

  20. A high-resolution vehicle emission inventory for China

    Science.gov (United States)

    Zheng, B.; Zhang, Q.; He, K.; Huo, H.; Yao, Z.; Wang, X.

    2012-12-01

    Developing high resolution emission inventory is an essential task for air quality modeling and management. However, current vehicle emission inventories in China are usually developed at provincial level and then allocated to grids based on various spatial surrogates, which is difficult to get high spatial resolution. In this work, we developed a new approach to construct a high-resolution vehicle emission inventory for China. First, vehicle population at county level were estimated by using the relationship between per-capita GDP and vehicle ownership. Then the Weather Research and Forecasting (WRF) model were used to drive the International Vehicle Emission (IVE) model to get monthly emission factors for each county. Finally, vehicle emissions by county were allocated to grids with 5-km horizon resolution by using high-resolution road network data. This work provides a better understanding of spatial representation of vehicle emissions in China and can benefit both air quality modeling and management with improved spatial accuracy.

  1. Towards optical intensity interferometry for high angular resolution stellar astrophysics

    CERN Document Server

    Nunez, Paul D

    2012-01-01

    Most neighboring stars are still detected as point sources and are beyond the angular resolution reach of current observatories. Methods to improve our understanding of stars at high angular resolution are investigated. Air Cherenkov telescopes (ACTs), primarily used for Gamma-ray astronomy, enable us to increase our understanding of the circumstellar environment of a particular system. When used as optical intensity interferometers, future ACT arrays will allow us to detect stars as extended objects and image their surfaces at high angular resolution. Optical stellar intensity interferometry (SII) with ACT arrays, composed of nearly 100 telescopes, will provide means to measure fundamental stellar parameters and also open the possibility of model-independent imaging. A data analysis algorithm is developed and permits the reconstruction of high angular resolution images from simulated SII data. The capabilities and limitations of future ACT arrays used for high angular resolution imaging are investigated via ...

  2. Research Relative to High Spatial Resolution Passive Microwave Sounding Systems

    Science.gov (United States)

    Staelin, D. H.; Rosenkranz, P. W.

    1984-01-01

    Methods to obtain high resolution passive microwave weather observations, and understanding of their probable impact on numerical weather prediction accuracy were investigated. The development of synthetic aperture concepts for geosynchronous passive microwave sounders were studied. The effects of clouds, precipitation, surface phenomena, and atmospheric thermal fine structure on a scale of several kilometers were examined. High resolution passive microwave sounders (e.g., AMSU) with an increased number of channels will produce initialization data for numerical weather prediction (NWP) models with both increased spatial resolution and coverage. The development of statistical models for error growth in high resolution primitive equation NWP models which permit the consequences of various observing system alternatives, including sensors and assimilation times and procedures is discussed. A high resolution three dimensional primitive equation NWP model to determine parameters in an error growth model similar to that formulated by Lorenz, but with more degrees of freedom is utilized.

  3. Whole-animal imaging with high spatio-temporal resolution

    Science.gov (United States)

    Chhetri, Raghav; Amat, Fernando; Wan, Yinan; Höckendorf, Burkhard; Lemon, William C.; Keller, Philipp J.

    2016-03-01

    We developed isotropic multiview (IsoView) light-sheet microscopy in order to image fast cellular dynamics, such as cell movements in an entire developing embryo or neuronal activity throughput an entire brain or nervous system, with high resolution in all dimensions, high imaging speeds, good physical coverage and low photo-damage. To achieve high temporal resolution and high spatial resolution at the same time, IsoView microscopy rapidly images large specimens via simultaneous light-sheet illumination and fluorescence detection along four orthogonal directions. In a post-processing step, these four views are then combined by means of high-throughput multiview deconvolution to yield images with a system resolution of ≤ 450 nm in all three dimensions. Using IsoView microscopy, we performed whole-animal functional imaging of Drosophila embryos and larvae at a spatial resolution of 1.1-2.5 μm and at a temporal resolution of 2 Hz for up to 9 hours. We also performed whole-brain functional imaging in larval zebrafish and multicolor imaging of fast cellular dynamics across entire, gastrulating Drosophila embryos with isotropic, sub-cellular resolution. Compared with conventional (spatially anisotropic) light-sheet microscopy, IsoView microscopy improves spatial resolution at least sevenfold and decreases resolution anisotropy at least threefold. Compared with existing high-resolution light-sheet techniques, such as lattice lightsheet microscopy or diSPIM, IsoView microscopy effectively doubles the penetration depth and provides subsecond temporal resolution for specimens 400-fold larger than could previously be imaged.

  4. High resolution resonant recombination measurements using evaporative cooling technique

    Energy Technology Data Exchange (ETDEWEB)

    Beilmann, C; Lopez-Urrutia, J R Crespo; Mokler, P H; Ullrich, J, E-mail: christian.beilmann@mpi-hd.mpg.d [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2010-09-15

    We report on a method significantly improving the energy resolution of dielectronic recombination (DR) measurements in electron beam ion traps (EBITs). The line width of DR resonances can be reduced to values distinctly smaller than the corresponding space charge width of the uncompensated electron beam. The experimental technique based on forced evaporative cooling is presented together with test measurements demonstrating its high efficiency. The principle for resolution improvement is elucidated and the limiting factors are discussed. This method opens access to high resolution DR measurements at high ion-electron collision energies required for innermost shell DR in highly charged ions (HCI).

  5. Cheetah: A high frame rate, high resolution SWIR image camera

    Science.gov (United States)

    Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

    2008-10-01

    A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 μm] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

  6. A high-resolution time-to-digital converter using a three-level resolution

    Science.gov (United States)

    Dehghani, Asma; Saneei, Mohsen; Mahani, Ali

    2016-08-01

    In this article, a three-level resolution Vernier delay line time-to-digital converter (TDC) was proposed. The proposed TDC core was based on the pseudo-differential digital architecture that made it insensitive to nMOS and pMOS transistor mismatches. It also employed a Vernier delay line (VDL) in conjunction with an asynchronous read-out circuitry. The time interval resolution was equal to the difference of delay between buffers of upper and lower chains. Then, via the extra chain included in the lower delay line, resolution was controlled and power consumption was reduced. This method led to high resolution and low power consumption. The measurement results of TDC showed a resolution of 4.5 ps, 12-bit output dynamic range, and integral nonlinearity of 1.5 least significant bits. This TDC achieved the consumption of 68.43 µW from 1.1-V supply.

  7. Updating Maps Using High Resolution Satellite Imagery

    Science.gov (United States)

    Alrajhi, Muhamad; Shahzad Janjua, Khurram; Afroz Khan, Mohammad; Alobeid, Abdalla

    2016-06-01

    Kingdom of Saudi Arabia is one of the most dynamic countries of the world. We have witnessed a very rapid urban development's which are altering Kingdom's landscape on daily basis. In recent years a substantial increase in urban populations is observed which results in the formation of large cities. Considering this fast paced growth, it has become necessary to monitor these changes, in consideration with challenges faced by aerial photography projects. It has been observed that data obtained through aerial photography has a lifecycle of 5-years because of delay caused by extreme weather conditions and dust storms which acts as hindrances or barriers during aerial imagery acquisition, which has increased the costs of aerial survey projects. All of these circumstances require that we must consider some alternatives that can provide us easy and better ways of image acquisition in short span of time for achieving reliable accuracy and cost effectiveness. The approach of this study is to conduct an extensive comparison between different resolutions of data sets which include: Orthophoto of (10 cm) GSD, Stereo images of (50 cm) GSD and Stereo images of (1 m) GSD, for map updating. Different approaches have been applied for digitizing buildings, roads, tracks, airport, roof level changes, filling stations, buildings under construction, property boundaries, mosques buildings and parking places.

  8. Sunspot Group Development in High Resolution

    CERN Document Server

    Muraközy, J; Ludmány, A

    2014-01-01

    The Solar and Heliospheric Obseratory/Michelson Doppler Imager--Debrecen Data (SDD) sunspot catalogue provides an opportunity to study the details and development of sunspot groups on a large statistical sample. The SDD data allow, in particular, the differential study of the leading and following parts with a temporal resolution of 1.5 hours. In this study, we analyse the equilibrium distance of sunspot groups as well as the evolution of this distance over the lifetime of the groups and the shifts in longitude associated with these groups. We also study the asymmetry between the compactness of the leading and following parts, as well as the time-profiles for the development of the area of sunspot groups. A logarithmic relationship has been found between the total area and the distance of leading-following parts of active regions (ARs) at the time of their maximum area. In the developing phase the leading part moves forward; this is more noticeable in larger ARs. The leading part has a higher growth rate than...

  9. Wide-field, high-resolution Fourier ptychographic microscopy

    CERN Document Server

    Zheng, Guoan; Yang, Changhuei

    2014-01-01

    In this article, we report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field, high-resolution complex sample image. By adopting a wavefront correction strategy, the FPM method can also correct for aberrations and digitally extend a microscope's depth-of-focus beyond the physical limitations of its optics. As a demonstration, we built a microscope prototype with a resolution of 0.78 um, a field-of-view of ~120 mm2, and a resolution-invariant depth-of-focus of 0.3 mm (characterized at 632 nm). Gigapixel colour images of histology slides verify FPM's successful operation. The reported imaging procedure transforms the general challenge of high-throughput, high-resolution microscopy from one that is coupled to the physical limitations of the system's optics to one that is solvable through computation.

  10. High resolution mid-infrared spectroscopy based on frequency upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Hu, Qi; Tidemand-Lichtenberg, Peter

    2013-01-01

    We present high resolution upconversion of incoherent infrared radiation by means of sum-frequency mixing with a laser followed by simple CCD Si-camera detection. Noise associated with upconversion is, in strong contrast to room temperature direct mid-IR detection, extremely small, thus very faint...... signals can be analyzed. The obtainable frequency resolution is usually in the nm range where sub nm resolution is preferred in many applications, like gas spectroscopy. In this work we demonstrate how to obtain sub nm resolution when using upconversion. In the presented realization one object point...

  11. Achieving High Resolution Timer Events in Virtualized Environment.

    Science.gov (United States)

    Adamczyk, Blazej; Chydzinski, Andrzej

    2015-01-01

    Virtual Machine Monitors (VMM) have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service). Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

  12. High-resolution spectroscopy of gases for industrial applications

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing...... to, for example, atmospheric research, combustion and gasification. Some high-temperature, high-resolution IR/UV absorption/transmission measurements gases (e.g. CO2, SO2, SO3 and phenol) are presented....

  13. Ultra-high resolution and high-brightness AMOLED

    Science.gov (United States)

    Wacyk, Ihor; Ghosh, Amal; Prache, Olivier; Draper, Russ; Fellowes, Dave

    2012-06-01

    As part of its continuing effort to improve both the resolution and optical performance of AMOLED microdisplays, eMagin has recently developed an SXGA (1280×3×1024) microdisplay under a US Army RDECOM CERDEC NVESD contract that combines the world's smallest OLED pixel pitch with an ultra-high brightness green OLED emitter. This development is aimed at next-generation HMD systems with "see-through" and daylight imaging requirements. The OLED pixel array is built on a 0.18-micron CMOS backplane and contains over 4 million individually addressable pixels with a pixel pitch of 2.7 × 8.1 microns, resulting in an active area of 0.52 inches diagonal. Using both spatial and temporal enhancement, the display can provide over 10-bits of gray-level control for high dynamic range applications. The new pixel design also enables the future implementation of a full-color QSXGA (2560 × RGB × 2048) microdisplay in an active area of only 1.05 inch diagonal. A low-power serialized low-voltage-differential-signaling (LVDS) interface is integrated into the display for use as a remote video link for tethered systems. The new SXGA backplane has been combined with the high-brightness green OLED device developed by eMagin under an NVESD contract. This OLED device has produced an output brightness of more than 8000fL with all pixels on; lifetime measurements are currently underway and will presented at the meeting. This paper will describe the operational features and first optical and electrical test results of the new SXGA demonstrator microdisplay.

  14. Spatially adaptive regularized iterative high-resolution image reconstruction algorithm

    Science.gov (United States)

    Lim, Won Bae; Park, Min K.; Kang, Moon Gi

    2000-12-01

    High resolution images are often required in applications such as remote sensing, frame freeze in video, military and medical imaging. Digital image sensor arrays, which are used for image acquisition in many imaging systems, are not dense enough to prevent aliasing, so the acquired images will be degraded by aliasing effects. To prevent aliasing without loss of resolution, a dense detector array is required. But it may be very costly or unavailable, thus, many imaging systems are designed to allow some level of aliasing during image acquisition. The purpose of our work is to reconstruct an unaliased high resolution image from the acquired aliased image sequence. In this paper, we propose a spatially adaptive regularized iterative high resolution image reconstruction algorithm for blurred, noisy and down-sampled image sequences. The proposed approach is based on a Constrained Least Squares (CLS) high resolution reconstruction algorithm, with spatially adaptive regularization operators and parameters. These regularization terms are shown to improve the reconstructed image quality by forcing smoothness, while preserving edges in the reconstructed high resolution image. Accurate sub-pixel motion registration is the key of the success of the high resolution image reconstruction algorithm. However, sub-pixel motion registration may have some level of registration error. Therefore, a reconstruction algorithm which is robust against the registration error is required. The registration algorithm uses a gradient based sub-pixel motion estimator which provides shift information for each of the recorded frames. The proposed algorithm is based on a technique of high resolution image reconstruction, and it solves spatially adaptive regularized constrained least square minimization functionals. In this paper, we show that the reconstruction algorithm gives dramatic improvements in the resolution of the reconstructed image and is effective in handling the aliased information. The

  15. Sensitivity study of reliable, high-throughput resolution metricsfor photoresists

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Christopher N.; Naulleau, Patrick P.

    2007-07-30

    The resolution of chemically amplified resists is becoming an increasing concern, especially for lithography in the extreme ultraviolet (EUV) regime. Large-scale screening and performance-based down-selection is currently underway to identify resist platforms that can support shrinking feature sizes. Resist screening efforts, however, are hampered by the absence of reliable resolution metrics that can objectively quantify resist resolution in a high-throughput fashion. Here we examine two high-throughput metrics for resist resolution determination. After summarizing their details and justifying their utility, we characterize the sensitivity of both metrics to two of the main experimental uncertainties associated with lithographic exposure tools, namely: limited focus control and limited knowledge of optical aberrations. For an implementation at EUV wavelengths, we report aberration and focus limited error bars in extracted resolution of {approx} 1.25 nm RMS for both metrics making them attractive candidates for future screening and down-selection efforts.

  16. Depth of interaction resolution measurements for a high resolution PET detector using position sensitive avalanche photodiodes.

    Science.gov (United States)

    Yang, Yongfeng; Dokhale, Purushottam A; Silverman, Robert W; Shah, Kanai S; McClish, Mickel A; Farrell, Richard; Entine, Gerald; Cherry, Simon R

    2006-05-07

    We explore dual-ended read out of LSO arrays with two position sensitive avalanche photodiodes (PSAPDs) as a high resolution, high efficiency depth-encoding detector for PET applications. Flood histograms, energy resolution and depth of interaction (DOI) resolution were measured for unpolished LSO arrays with individual crystal sizes of 1.0, 1.3 and 1.5 mm, and for a polished LSO array with 1.3 mm pixels. The thickness of the crystal arrays was 20 mm. Good flood histograms were obtained for all four arrays, and crystals in all four arrays can be clearly resolved. Although the amplitude of each PSAPD signal decreases as the interaction depth moves further from the PSAPD, the sum of the two PSAPD signals is essentially constant with irradiation depth for all four arrays. The energy resolutions were similar for all four arrays, ranging from 14.7% to 15.4%. A DOI resolution of 3-4 mm (including the width of the irradiation band which is approximately 2 mm) was obtained for all the unpolished arrays. The best DOI resolution was achieved with the unpolished 1 mm array (average 3.5 mm). The DOI resolution for the 1.3 mm and 1.5 mm unpolished arrays was 3.7 and 4.0 mm respectively. For the polished array, the DOI resolution was only 16.5 mm. Summing the DOI profiles across all crystals for the 1 mm array only degraded the DOI resolution from 3.5 mm to 3.9 mm, indicating that it may not be necessary to calibrate the DOI response separately for each crystal within an array. The DOI response of individual crystals in the array confirms this finding. These results provide a detailed characterization of the DOI response of these PSAPD-based PET detectors which will be important in the design and calibration of a PET scanner making use of this detector approach.

  17. High Resolution CryoFESEM of Microbial Surfaces

    Science.gov (United States)

    Erlandsen, Stanley; Lei, Ming; Martin-Lacave, Ines; Dunny, Gary; Wells, Carol

    2003-08-01

    The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at [minus sign]125°C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to “cracking” of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.

  18. High Resolution Orthoimagery = Orthorectified Metro Areas: 2000 - Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — High resolution orthorectified images combine the image characteristics of an aerial photograph with the geometric qualities of a map. An orthoimage is a...

  19. High-resolution SPECT for small-animal imaging

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This article presents a brief overview of the development of high-resolution SPECT for small-animal imaging. A pinhole collimator has been used for high-resolution animal SPECT to provide better spatial resolution and detection efficiency in comparison with a parallel-hole collimator. The theory of imaging characteristics of the pinhole collimator is presented and the designs of the pinhole aperture are discussed. The detector technologies used for the development of small-animal SPECT and the recent advances are presented. The evolving trend of small-animal SPECT is toward a multi-pinhole and a multi-detector system to obtain a high resolution and also a high detection efficiency.

  20. Methodology of high-resolution photography for mural condition database

    Science.gov (United States)

    Higuchi, R.; Suzuki, T.; Shibata, M.; Taniguchi, Y.

    2015-08-01

    Digital documentation is one of the most useful techniques to record the condition of cultural heritage. Recently, high-resolution images become increasingly useful because it is possible to show general views of mural paintings and also detailed mural conditions in a single image. As mural paintings are damaged by environmental stresses, it is necessary to record the details of painting condition on high-resolution base maps. Unfortunately, the cost of high-resolution photography and the difficulty of operating its instruments and software have commonly been an impediment for researchers and conservators. However, the recent development of graphic software makes its operation simpler and less expensive. In this paper, we suggest a new approach to make digital heritage inventories without special instruments, based on our recent our research project in Üzümlü church in Cappadocia, Turkey. This method enables us to achieve a high-resolution image database with low costs, short time, and limited human resources.

  1. High Resolution Screening of biologically active compounds and metabolites

    NARCIS (Netherlands)

    Kool, J.

    2007-01-01

    High Resolution Screening of biologically active compounds and metabolites Jeroen Kool Biotransformation enzymes play a crucial role in the metabolism of both endogenous compounds and xenobiotics. Usually, the detoxication of these compounds by biotransformation enzymes results in harmless metab

  2. NOAA High-Resolution Sea Surface Temperature (SST) Analysis Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archive covers two high resolution sea surface temperature (SST) analysis products developed using an optimum interpolation (OI) technique. The analyses have a...

  3. High Resolution, Range/Range-Rate Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Visidyne proposes to develop a design for a small, lightweight, high resolution, in x, y, and z Doppler imager to assist in the guidance, navigation and control...

  4. Using High Spatial Resolution Digital Imagery

    Science.gov (United States)

    2005-02-01

    frame and a bright area (hot spot) at the center. The same brightness shifts are present within most aerial photography , particularly the pronounced hot...the deciduous trees and shrubs were without leaves. In addition, the reed and grass species were fully senesced . The lack of photosynthetically...For example, high quality, large-scale aerial photography will provide adequate clarity and detail to accurately identify surface features that are

  5. High resolution survey for topographic surveying

    Science.gov (United States)

    Luh, L. C.; Setan, H.; Majid, Z.; Chong, A. K.; Tan, Z.

    2014-02-01

    In this decade, terrestrial laser scanner (TLS) is getting popular in many fields such as reconstruction, monitoring, surveying, as-built of facilities, archaeology, and topographic surveying. This is due the high speed in data collection which is about 50,000 to 1,000,000 three-dimensional (3D) points per second at high accuracy. The main advantage of 3D representation for the data is that it is more approximate to the real world. Therefore, the aim of this paper is to show the use of High-Definition Surveying (HDS), also known as 3D laser scanning for topographic survey. This research investigates the effectiveness of using terrestrial laser scanning system for topographic survey by carrying out field test in Universiti Teknologi Malaysia (UTM), Skudai, Johor. The 3D laser scanner used in this study is a Leica ScanStation C10. Data acquisition was carried out by applying the traversing method. In this study, the result for the topographic survey is under 1st class survey. At the completion of this study, a standard of procedure was proposed for topographic data acquisition using laser scanning systems. This proposed procedure serves as a guideline for users who wish to utilize laser scanning system in topographic survey fully.

  6. Developing Visual Editors for High-Resolution Haptic Patterns

    DEFF Research Database (Denmark)

    Cuartielles, David; Göransson, Andreas; Olsson, Tony

    2012-01-01

    In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit high...... resolution haptic patterns so that they translate naturally to the user’s haptic experience. To solve this question we have developed and tested several visual editors...

  7. High resolution computed tomography for peripheral facial nerve paralysis

    Energy Technology Data Exchange (ETDEWEB)

    Koester, O.; Straehler-Pohl, H.J.

    1987-01-01

    High resolution computer tomographic examinations of the petrous bones were performed on 19 patients with confirmed peripheral facial nerve paralysis. High resolution CT provides accurate information regarding the extent, and usually regarding the type, of pathological process; this can be accurately localised with a view to possible surgical treatments. The examination also differentiates this from idiopathic paresis, which showed no radiological changes. Destruction of the petrous bone, without facial nerve symptoms, makes early suitable treatment mandatory.

  8. Geometric calibration of high-resolution remote sensing sensors

    Institute of Scientific and Technical Information of China (English)

    LIANG Hong-you; GU Xing-fa; TAO Yu; QIAO Chao-fei

    2007-01-01

    This paper introduces the applications of high-resolution remote sensing imagery and the necessity of geometric calibration for remote sensing sensors considering assurance of the geometric accuracy of remote sensing imagery. Then the paper analyzes the general methodology of geometric calibration. Taking the DMC sensor geometric calibration as an example, the paper discusses the whole calibration procedure. Finally, it gave some concluding remarks on geometric calibration of high-resolution remote sensing sensors.

  9. Scalable Algorithms for Large High-Resolution Terrain Data

    DEFF Research Database (Denmark)

    Mølhave, Thomas; Agarwal, Pankaj K.; Arge, Lars Allan

    2010-01-01

    In this paper we demonstrate that the technology required to perform typical GIS computations on very large high-resolution terrain models has matured enough to be ready for use by practitioners. We also demonstrate the impact that high-resolution data has on common problems. To our knowledge, some...... of the computations we present have never before been carried out by standard desktop computers on data sets of comparable size....

  10. Dynamics of High-Resolution Networks

    DEFF Research Database (Denmark)

    Sekara, Vedran

    NETWORKS are everywhere. From the smallest confines of the cells within our bodies to the webs of social relations across the globe. Networks are not static, they constantly change, adapt, and evolve to suit new conditions. In order to understand the fundamental laws that govern networks we need...... the unprecedented amounts of information collected by mobile phones to gain detailed insight into the dynamics of social systems. This dissertation presents an unparalleled data collection campaign, collecting highly detailed traces for approximately 1000 people over the course of multiple years. The availability...

  11. High-resolution noise radar using slow ADC

    Science.gov (United States)

    Lukin, Konstantin; Vyplavin, Pavlo; Zemlyanyi, Oleg; Lukin, Sergiy; Palamarchuk, Volodymyr

    2011-06-01

    Conventional digital signal processing scheme in noise radars has some limitations related to combination of high resolution and high dynamic range. Those limitations are caused by a tradeoff in performance of currently available ADCs: the faster is ADC the smaller is its depth (number of bits) available. Depth of the ADC determines relation between the smallest and highest observable signals and thus limits its dynamic range. In noise radar with conventional processing the sounding and reference signals are to be digitized at intermediate frequency band and to be processed digitally. The power spectrum bandwidth of noise signal which can be digitized with ADC depends on its sampling rate. The bandwidth of radar signal defines range resolution of any radar: the wider the spectrum the better the resolution. Actually this is the main bottleneck of high resolution Noise Radars: conventional processing doesn't enable to get both high range resolution and high dynamic range. In the paper we present a way to go around this drawback by changing signal processing ideology in noise radar. We present results of our consideration and design of high resolution Noise Radar which uses slow ADCs. The design is based upon generation of both probing and reference signals digitally and realization of their cross-correlation in an analog correlator. The output of the correlator is a narrowband signal that requires rather slow ADC to be sampled which nowadays may give up to 130 dB dynamic range.

  12. High resolution 3-D wavelength diversity imaging

    Science.gov (United States)

    Farhat, N. H.

    1981-09-01

    A physical optics, vector formulation of microwave imaging of perfectly conducting objects by wavelength and polarization diversity is presented. The results provide the theoretical basis for optimal data acquisition and three-dimensional tomographic image retrieval procedures. These include: (a) the selection of highly thinned (sparse) receiving array arrangements capable of collecting large amounts of information about remote scattering objects in a cost effective manner and (b) techniques for 3-D tomographic image reconstruction and display in which polarization diversity data is fully accounted for. Data acquisition employing a highly attractive AMTDR (Amplitude Modulated Target Derived Reference) technique is discussed and demonstrated by computer simulation. Equipment configuration for the implementation of the AMTDR technique is also given together with a measurement configuration for the implementation of wavelength diversity imaging in a roof experiment aimed at imaging a passing aircraft. Extension of the theory presented to 3-D tomographic imaging of passive noise emitting objects by spectrally selective far field cross-correlation measurements is also given. Finally several refinements made in our anechoic-chamber measurement system are shown to yield drastic improvement in performance and retrieved image quality.

  13. High-resolution gravity model of Venus

    Science.gov (United States)

    Reasenberg, R. D.; Goldberg, Z. M.

    1992-01-01

    The anomalous gravity field of Venus shows high correlation with surface features revealed by radar. We extract gravity models from the Doppler tracking data from the Pioneer Venus Orbiter by means of a two-step process. In the first step, we solve the nonlinear spacecraft state estimation problem using a Kalman filter-smoother. The Kalman filter has been evaluated through simulations. This evaluation and some unusual features of the filter are discussed. In the second step, we perform a geophysical inversion using a linear Bayesian estimator. To allow an unbiased comparison between gravity and topography, we use a simulation technique to smooth and distort the radar topographic data so as to yield maps having the same characteristics as our gravity maps. The maps presented cover 2/3 of the surface of Venus and display the strong topography-gravity correlation previously reported. The topography-gravity scatter plots show two distinct trends.

  14. A Very High Spatial Resolution Detector for Small Animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Kanai Shah, M.S.

    2007-03-06

    Positron Emission Tomography (PET) is an in vivo analog of autoradiography and has the potential to become a powerful new tool in imaging biological processes in small laboratory animals. PET imaging of small animals can provide unique information that can help in advancement of human disease models as well as drug development. Clinical PET scanners used for human imaging are bulky, expensive and do not have adequate spatial resolution for small animal studies. Hence, dedicated, low cost instruments are required for conducting small animal studies with higher spatial resolution than what is currently achieved with clinical as well as dedicated small animal PET scanners. The goal of the proposed project is to investigate a new all solid-state detector design for small animal PET imaging. Exceptionally high spatial resolution, good timing resolution, and excellent energy resolution are expected from the proposed detector design. The Phase I project was aimed at demonstrating the feasibility of producing high performance solid-state detectors that provide high sensitivity, spatial resolution, and timing characteristics. Energy resolution characteristics of the new detector were also investigated. The goal of the Phase II project is to advance the promising solid-state detector technology for small animal PET and determine its full potential. Detectors modules will be built and characterized and finally, a bench-top small animal PET system will be assembled and evaluated.

  15. High-resolution spectroscopy of gamma-ray transients

    Energy Technology Data Exchange (ETDEWEB)

    Cline, T.L.

    1988-09-25

    The first high-resolution spectrometer flown to observe gamma-ray bursts was launched on the ISEE-3 spacecraft over nine years ago. It recorded two events before instrument failure, giving results that were suggestive but marginal. Other studies, with coarser energy resolution, also show evidence for spectral features as well as for spectral evolution on short time scales. Absolute source strength calibration will be possible only with source identification, but understanding of the burst emission processes will surely come only from the measurements having the best spectral and temporal precision. The only high- resolution gamma-ray spectrometer now planned, here or abroad, for space flight is an instrument sequel to the ISEE-3 spectrometer, to be flown on the interplanetary 'GGS Wind' mission. Much larger and higher-sensitivity, high-resolution instruments may have their optimum opportunities in conjunction with studies of solar flares in the time frame of the solar maximum of 2002.

  16. Compact and high-resolution optical orbital angular momentum sorter

    Directory of Open Access Journals (Sweden)

    Chenhao Wan

    2017-03-01

    Full Text Available A compact and high-resolution optical orbital angular momentum (OAM sorter is proposed and demonstrated. The sorter comprises a quadratic fan-out mapper and a dual-phase corrector positioned in the pupil plane and the Fourier plane, respectively. The optical system is greatly simplified compared to previous demonstrations of OAM sorting, and the performance in resolution and efficiency is maintained. A folded configuration is set up using a single reflective spatial light modulator (SLM to demonstrate the validity of the scheme. The two phase elements are implemented on the left and right halves of the SLM and connected by a right-angle prism. Experimental results demonstrate the high resolution of the compact OAM sorter, and the current limit in efficiency can be overcome by replacing with transmissive SLMs and removing the beam splitters. This novel scheme paves the way for the miniaturization and integration of high-resolution OAM sorters.

  17. Climatologies at high resolution for the Earth land surface areas

    CERN Document Server

    Karger, Dirk Nikolaus; Böhner, Jürgen; Kawohl, Tobias; Kreft, Holger; Soria-Auza, Rodrigo Wilber; Zimmermann, Niklaus; Linder, H Peter; Kessler, Michael

    2016-01-01

    High resolution information of climatic conditions is essential to many application in environmental sciences. Here we present the CHELSA algorithm to downscale temperature and precipitation estimates from the European Centre for Medium-Range Weather Forecast (ECMWF) climatic reanalysis interim (ERA-Interim) to a high resolution of 30 arc sec. The algorithm for temperature is based on a statistical downscaling of atmospheric temperature from the ERA-Interim climatic reanalysis. The precipitation algorithm incorporates orographic predictors such as wind fields, valley exposition, and boundary layer height, and a bias correction using Global Precipitation Climatology Center (GPCC) gridded and Global Historical Climate Network (GHCN) station data. The resulting data consist of a monthly temperature and precipitation climatology for the years 1979-2013. We present a comparison of data derived from the CHELSA algorithm with two other high resolution gridded products with overlapping temporal resolution (Tropical R...

  18. High resolution single particle refinement in EMAN2.1.

    Science.gov (United States)

    Bell, James M; Chen, Muyuan; Baldwin, Philip R; Ludtke, Steven J

    2016-05-01

    EMAN2.1 is a complete image processing suite for quantitative analysis of grayscale images, with a primary focus on transmission electron microscopy, with complete workflows for performing high resolution single particle reconstruction, 2-D and 3-D heterogeneity analysis, random conical tilt reconstruction and subtomogram averaging, among other tasks. In this manuscript we provide the first detailed description of the high resolution single particle analysis pipeline and the philosophy behind its approach to the reconstruction problem. High resolution refinement is a fully automated process, and involves an advanced set of heuristics to select optimal algorithms for each specific refinement task. A gold standard FSC is produced automatically as part of refinement, providing a robust resolution estimate for the final map, and this is used to optimally filter the final CTF phase and amplitude corrected structure. Additional methods are in-place to reduce model bias during refinement, and to permit cross-validation using other computational methods.

  19. High resolution temperature measurement technique for measuring marine heat flow

    Institute of Scientific and Technical Information of China (English)

    QIN; YangYang; YANG; XiaoQiu; WU; BaoZhen; SUN; ZhaoHua; SHI; XiaoBin

    2013-01-01

    High resolution temperature measurement technique is one of the key techniques for measuring marine heat flow. Basing on Pt1000 platinum resistance which has the characteristics of high accuracy and good stability, we designed a bridge reversal excitation circuit for high resolution temperature measurement. And the deep ocean floor in-situ test results show that: (1) temperature deviation and peak-to-peak resolution of the first version circuit board (V1) are 1.960-1.990 mK and 0.980-0.995 m Kat 1.2-2.7°C, respectively; and temperature deviation and peak-to-peak resolution of the second circuit board (V2) are 2.260mK and 1.130 mK at 1.2-1.3°C, respectively; (2) During the 2012NSFC-IndOcean cruise, seafloor geothermal gradient at Ind2012HF03,-07 and-12 stations (water depth ranges from 3841 to 4541 m) were successfully measured, the values are 59.1,75.1 and 71.6°C/km, respectively. And the measurement errors of geothermal gradient at these three stations are less than 3.0% in terms of the peak-to-peak resolution. These indicate that the high resolution temperature measurement technique based on Pt1000 platinum resistance in this paper can be applied to marine heat flow measurement to obtain high precision geothermal parameters.

  20. High resolution surface plasmon microscopy for cell imaging

    Science.gov (United States)

    Argoul, F.; Monier, K.; Roland, T.; Elezgaray, J.; Berguiga, L.

    2010-04-01

    We introduce a new non-labeling high resolution microscopy method for cellular imaging. This method called SSPM (Scanning Surface Plasmon Microscopy) pushes down the resolution limit of surface plasmon resonance imaging (SPRi) to sub-micronic scales. High resolution SPRi is obtained by the surface plasmon lauching with a high numerical aperture objective lens. The advantages of SPPM compared to other high resolution SPRi's rely on three aspects; (i) the interferometric detection of the back reflected light after plasmon excitation, (ii) the twodimensional scanning of the sample for image reconstruction, (iii) the radial polarization of light, enhancing both resolution and sensitivity. This microscope can afford a lateral resolution of - 150 nm in liquid environment and - 200 nm in air. We present in this paper images of IMR90 fibroblasts obtained with SSPM in dried environment. Internal compartments such as nucleus, nucleolus, mitochondria, cellular and nuclear membrane can be recognized without labelling. We propose an interpretation of the ability of SSPM to reveal high index contrast zones by a local decomposition of the V (Z) function describing the response of the SSPM.

  1. Liquid Scintillation High Resolution Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A.

    2010-08-06

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  2. A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments

    OpenAIRE

    Khachaturian, Mark Haig

    2010-01-01

    Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major...

  3. A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments.

    Science.gov (United States)

    Khachaturian, Mark Haig

    2010-01-01

    Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic).

  4. High-resolution spectroscopy of gases for industrial applications

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing...... for analysis of complex experimental data and further development of the databases. High-temperature gas cell facilities available at DTU Chemical Engineering are presented and described. The gas cells and high-resolution spectrometers allow us to perform high-quality reference measurements of gases relevant...

  5. High resolution positron tomography using PCR-I

    Energy Technology Data Exchange (ETDEWEB)

    Brownell, G.L.; Burnham, C.A.; Sandrew, B.; Elmaleh, D.R.; Livni, E.; Kizuka, H.

    1984-01-01

    PCR-I is a high resolution positron tomograph developed by the Physics Research Laboratory of the Massachusetts General Hospital to explore resolution limits of positron tomographs. PCR-I currently obtains images with 4.8 mm FWHM resolution at the center. Plane thickness may be varied between 5 and 10 mm. The instrument uses analog coding to obtain high resolution images without mechanical motion. This permits rapid dynamic imaging and gated cardiac imaging as well as conventional high resolution imaging. A series of studies has been carried out to demonstrate the ability of PCR-I to image structures in small animals. F-18 in the rat skeleton is clearly defined and various structures such as the spinal processes can be clearly resolved. A sequence of images at different spacing provides a three-dimensional reconstruction of the rat skeleton. Blood volume and palmitic acid have been imaged in the dog heart. Again, the sequence of images provides a clear delineation of the three dimensional nature of the blood pools and of the surrounding musculature. Blood flow, blood volume and glucose metabolism have been studied in the monkey brain. Structures within the brain of the Resus monkey can be clearly resolved. Increased activity resulting from induced seizures in the squirrel monkey have been observed and delineated. All of these studies indicate areas of future animal and clinical research using the high resolution tomograph, PCR-I.

  6. High-resolution neutron microtomography with noiseless neutron counting detector

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Feller, W.B. [Nova Scientific Inc., 10 Picker Road, Sturbridge, MA 01566 (United States); Lehmann, E. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Butler, L.G. [Louisiana State University, Baton Rouge, LA 70803 (United States); Dawson, M. [Helmholtz Centre Berlin for Materials and Energy (Germany)

    2011-10-01

    The improved collimation and intensity of thermal and cold neutron beamlines combined with recent advances in neutron imaging devices enable high-resolution neutron radiography and microtomography, which can provide information on the internal structure of objects not achievable with conventional X-ray imaging techniques. Neutron detection efficiency, spatial and temporal resolution (important for the studies of dynamic processes) and low background count rate are among the crucial parameters defining the quality of radiographic images and tomographic reconstructions. The unique capabilities of neutron counting detectors with neutron-sensitive microchannel plates (MCPs) and with Timepix CMOS readouts providing high neutron detection efficiency ({approx}70% for cold neutrons), spatial resolutions ranging from 15 to 55 {mu}m and a temporal resolution of {approx}1 {mu}s-combined with the virtual absence of readout noise-make these devices very attractive for high-resolution microtomography. In this paper we demonstrate the capabilities of an MCP-Timepix detection system applied to microtomographic imaging, performed at the ICON cold neutron facility of the Paul Scherrer Institute. The high resolution and the absence of readout noise enable accurate reconstruction of texture in a relatively opaque wood sample, differentiation of internal tissues of a fly and imaging of individual {approx}400 {mu}m grains in an organic powder encapsulated in a {approx}700 {mu}m thick metal casing.

  7. Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Ying-Xu [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); Mjøs, Svein Are, E-mail: svein.mjos@kj.uib.no [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); David, Fabrice P.A. [Bioinformatics and Biostatistics Core Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) and Swiss Institute of Bioinformatics (SIB), Lausanne (Switzerland); Schmid, Adrien W. [Proteomics Core Facility, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2016-03-31

    Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

  8. Accelerated High-Resolution Photoacoustic Tomography via Compressed Sensing

    CERN Document Server

    Arridge, Simon; Betcke, Marta; Cox, Ben; Huynh, Nam; Lucka, Felix; Ogunlade, Olumide; Zhang, Edward

    2016-01-01

    Current 3D photoacoustic tomography (PAT) systems offer either high image quality or high frame rates but are not able to deliver high spatial and temporal resolution simultaneously, which limits their ability to image dynamic processes in living tissue. A particular example is the planar Fabry-Perot (FP) scanner, which yields high-resolution images but takes several minutes to sequentially map the photoacoustic field on the sensor plane, point-by-point. However, as the spatio-temporal complexity of many absorbing tissue structures is rather low, the data recorded in such a conventional, regularly sampled fashion is often highly redundant. We demonstrate that combining variational image reconstruction methods using spatial sparsity constraints with the development of novel PAT acquisition systems capable of sub-sampling the acoustic wave field can dramatically increase the acquisition speed while maintaining a good spatial resolution: First, we describe and model two general spatial sub-sampling schemes. Then...

  9. High Resolution Muon Computed Tomography at Neutrino Beam Facilities

    CERN Document Server

    Suerfu, Burkhant

    2015-01-01

    X-ray computed tomography (CT) has an indispensable role in constructing 3D images of objects made from light materials. However, limited by absorption coefficients, X-rays cannot deeply penetrate materials such as copper and lead. Here we show via simulation that muon beams can provide high resolution tomographic images of dense objects and of structures within the interior of dense objects. The effects of resolution broadening from multiple scattering diminish with increasing muon momentum. As the momentum of the muon increases, the contrast of the image goes down and therefore requires higher resolution in the muon spectrometer to resolve the image. The variance of the measured muon momentum reaches a minimum and then increases with increasing muon momentum. The impact of the increase in variance is to require a higher integrated muon flux to reduce fluctuations. The flux requirements and level of contrast needed for high resolution muon computed tomography are well matched to the muons produced in the pio...

  10. Performance of a high resolution cavity beam position monitor system

    Science.gov (United States)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Pete; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; Thomson, Mark; Urakawa, Junji; Vogel, Vladimir; Ward, David; White, Glen

    2007-07-01

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than 1 nm. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 μrad over a dynamic range of approximately ±20 μm.

  11. Resolution-recovery-embedded image reconstruction for a high-resolution animal SPECT system.

    Science.gov (United States)

    Zeraatkar, Navid; Sajedi, Salar; Farahani, Mohammad Hossein; Arabi, Hossein; Sarkar, Saeed; Ghafarian, Pardis; Rahmim, Arman; Ay, Mohammad Reza

    2014-11-01

    The small-animal High-Resolution SPECT (HiReSPECT) is a dedicated dual-head gamma camera recently designed and developed in our laboratory for imaging of murine models. Each detector is composed of an array of 1.2 × 1.2 mm(2) (pitch) pixelated CsI(Na) crystals. Two position-sensitive photomultiplier tubes (H8500) are coupled to each head's crystal. In this paper, we report on a resolution-recovery-embedded image reconstruction code applicable to the system and present the experimental results achieved using different phantoms and mouse scans. Collimator-detector response functions (CDRFs) were measured via a pixel-driven method using capillary sources at finite distances from the head within the field of view (FOV). CDRFs were then fitted by independent Gaussian functions. Thereafter, linear interpolations were applied to the standard deviation (σ) values of the fitted Gaussians, yielding a continuous map of CDRF at varying distances from the head. A rotation-based maximum-likelihood expectation maximization (MLEM) method was used for reconstruction. A fast rotation algorithm was developed to rotate the image matrix according to the desired angle by means of pre-generated rotation maps. The experiments demonstrated improved resolution utilizing our resolution-recovery-embedded image reconstruction. While the full-width at half-maximum (FWHM) radial and tangential resolution measurements of the system were over 2 mm in nearly all positions within the FOV without resolution recovery, reaching around 2.5 mm in some locations, they fell below 1.8 mm everywhere within the FOV using the resolution-recovery algorithm. The noise performance of the system was also acceptable; the standard deviation of the average counts per voxel in the reconstructed images was 6.6% and 8.3% without and with resolution recovery, respectively.

  12. Isotope specific resolution recovery image reconstruction in high resolution PET imaging.

    Science.gov (United States)

    Kotasidis, Fotis A; Angelis, Georgios I; Anton-Rodriguez, Jose; Matthews, Julian C; Reader, Andrew J; Zaidi, Habib

    2014-05-01

    Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The

  13. Extension of least squares spectral resolution algorithm to high-resolution lipidomics data.

    Science.gov (United States)

    Zeng, Ying-Xu; Mjøs, Svein Are; David, Fabrice P A; Schmid, Adrien W

    2016-03-31

    Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis.

  14. Study of Saturn electrostatic discharges with high time resolution

    Science.gov (United States)

    Zakharenko, V.; Mylostna, K.; Konovalenko, A.; Kolyadin, V.; Zarka, P.; Griessmeier, J.-M.; Litvinenko, G.; Sidorchuk, M.; Rucker, H.; Fischer, G.; Cecconi, B.; Coffre, A.; Denis, L.; Shevchenko, V.; Nikolaenko, V.

    2013-09-01

    Ground-based observations of SED (Saturn Electrostatic Discharges) with high time resolution are the next stage of extraterrestrial atmospheric processes study. Due to extremely high intensity of Saturn's storm J (2010) [1] we have obtained the records with high signal-to-noise (S/N) ratio with the time resolution of 15 ns. It permitted us to investigate the microsecond structure of lightning and clearly distinguish SED in the presence of local interference in virtue of a dispersive delay of extraterrestrial planetary signals.

  15. Evacuee Compliance Behavior Analysis using High Resolution Demographic Information

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei [ORNL; Han, Lee [University of Tennessee, Knoxville (UTK); Liu, Cheng [ORNL; Tuttle, Mark A [ORNL; Bhaduri, Budhendra L [ORNL

    2014-01-01

    The purpose of this study is to examine whether evacuee compliance behavior with route assignments from different resolutions of demographic data would impact the evacuation performance. Most existing evacuation strategies assume that travelers will follow evacuation instructions, while in reality a certain percent of evacuees do not comply with prescribed instructions. In this paper, a comparison study of evacuation assignment based on Traffic Analysis Zones (TAZ) and high resolution LandScan USA Population Cells (LPC) were conducted for the detailed road network representing Alexandria, Virginia. A revised platform for evacuation modeling built on high resolution demographic data and activity-based microscopic traffic simulation is proposed. The results indicate that evacuee compliance behavior affects evacuation efficiency with traditional TAZ assignment, but it does not significantly compromise the efficiency with high resolution LPC assignment. The TAZ assignment also underestimates the real travel time during evacuation, especially for high compliance simulations. This suggests that conventional evacuation studies based on TAZ assignment might not be effective at providing efficient guidance to evacuees. From the high resolution data perspective, traveler compliance behavior is an important factor but it does not impact the system performance significantly. The highlight of evacuee compliance behavior analysis should be emphasized on individual evacuee level route/shelter assignments, rather than the whole system performance.

  16. Design and implementation of spaceborne high resolution infrared touch screen

    Science.gov (United States)

    Li, Tai-guo; Li, Wen-xin; Dong, Yi-peng; Ma, Wen; Xia, Jia-gao

    2015-10-01

    For the consideration of the special application environment of the electronic products used in aerospace and to further more improve the human-computer interaction of the manned aerospace area. The research is based on the design and implementation way of the high resolution spaceborne infrared touch screen on the basis of FPGA and DSP frame structure. Beside the introduction of the whole structure for the high resolution spaceborne infrared touch screen system, this essay also gives the detail information about design of hardware for the high resolution spaceborne infrared touch screen system, FPGA design, GUI design and DSP algorithm design based on Lagrange interpolation. What is more, the easy makes a comprehensive research of the reliability design for the high resolution spaceborne infrared touch screen for the special purpose of it. Besides, the system test is done after installation of spaceborne infrared touch screen. The test result shows that the system is simple and reliable enough, which has a stable running environment and high resolution, which certainly can meet the special requirement of the manned aerospace instrument products.

  17. Developing Visual Editors for High-Resolution Haptic Patterns

    DEFF Research Database (Denmark)

    Cuartielles, David; Göransson, Andreas; Olsson, Tony;

    2012-01-01

    In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit high...

  18. Stars and planets at high spatial and spectral resolution

    NARCIS (Netherlands)

    Albrecht, Simon

    2008-01-01

    The work presented in this thesis involves the development of new instrumental techniques and analysing tools, combining high spectral resolution with high spatial information, with the aim to increase our understanding of the formation and evolution of stars and planets. First, a novel instrumental

  19. Achieving High Resolution Timer Events in Virtualized Environment.

    Directory of Open Access Journals (Sweden)

    Blazej Adamczyk

    Full Text Available Virtual Machine Monitors (VMM have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service. Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

  20. High-resolution structure of viruses from random diffraction snapshots

    CERN Document Server

    Hosseinizadeh, A; Dashti, A; Fung, R; D'Souza, R M; Ourmazd, A

    2014-01-01

    The advent of the X-ray Free Electron Laser (XFEL) has made it possible to record diffraction snapshots of biological entities injected into the X-ray beam before the onset of radiation damage. Algorithmic means must then be used to determine the snapshot orientations and thence the three-dimensional structure of the object. Existing Bayesian approaches are limited in reconstruction resolution typically to 1/10 of the object diameter, with the computational expense increasing as the eighth power of the ratio of diameter to resolution. We present an approach capable of exploiting object symmetries to recover three-dimensional structure to high resolution, and thus reconstruct the structure of the satellite tobacco necrosis virus to atomic level. Our approach offers the highest reconstruction resolution for XFEL snapshots to date, and provides a potentially powerful alternative route for analysis of data from crystalline and nanocrystalline objects.

  1. New high resolution synthetic stellar libraries for the Gaia Mission

    CERN Document Server

    Sordo, R; Bouret, J C; Brott, I; Edvardsson, B; Frémat, Y; Heber, U; Josselin, E; Kochukhov, O; Korn, A; Lanzafame, A; Martins, F; Schweitzer, A; Thévenin, F; Zorec, J

    2008-01-01

    High resolution synthetic stellar libraries are of fundamental importance for the preparation of the Gaia Mission. We present new sets of spectral stellar libraries covering two spectral ranges: 300 --1100 nm at 0.1 nm resolution, and 840 -- 890 nm at 0.001 nm resolution. These libraries span a large range in atmospheric parameters, from super-metal-rich to very metal-poor (-5.0 $<$[Fe/H]$<$+1.0), from cool to hot (\\teff=3000--50000 K) stars, including peculiar abundance variations. The spectral resolution, spectral type coverage and number of models represent a substantial improvement over previous libraries used in population synthesis models and in atmospheric analysis.

  2. Subcutaneous Cysticercosis: Role of High Resolution Ultrasound in Diagnosis

    Directory of Open Access Journals (Sweden)

    Sachin Lohra

    2014-02-01

    Full Text Available BACKGROUND: Though the commonest site of extraintestinal infestation with Taenia solium is brain, Subcutaneous cysticercosis is fairly common in asia. The advent of high resolution ultrasound, FNAC, and a heightened clinician awareness of the existence of isolated soft tissue cysticerci has probably supplanted the need for surgical intervention and excision biopsy in asymptomatic subcutaneous cysts, as cysts have high rate of spontaneous resolution. OBJECTIVES: - To observe role of high resolution ultrasound in diagnosis and need of surgical intervention in treatment of subcutaneous cysticercosis. MATERIALS and METHODS: retrospective study of seven cases of extraneural cysticercosis, all involving the subcutaneous tissues or muscles over the arms and torso. Either high resolution ultrasound, FNAC, or excision biopsy, or a combination of these were used to arrive at a diagnosis. All patients were followed up with serial ultrasounds. All patients received oral nitazoxanide for autoinfection. Surgical excision was resorted to in two patients, in whom it was possible to obtain a histopathologic diagnosis. RESULTS: of the seven cases of subcutaneous cysticercosis all have rural background, most of the patients (6 were vegetarian and one was non vegetarian. Age and gender of patient, size and duration of lesion were insignificant in establishing the diagnosis. High resolution ultrasound was highly significant in establishing the diagnosis over FNAC and histopathology. Five of the cases resolved spontaneously and surgical intervention was required only in two cases. INTERPRETATION and CONCLUSIONS: With heightened clinician awareness of the existence of isolated subcutaneous cysticercosis in patients with close animal contact, and the widespread availability of high resolution ultrasound and FNAC, subcutaneous cysticercosis can be diagnosed readily. Surgery can be avoided in the great majority of these patients, as the cysts mostly resolve on their own

  3. High-resolution DEM Effects on Geophysical Flow Models

    Science.gov (United States)

    Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.

    2014-12-01

    Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (<10-15°) slope angles are involved. At these slope angles, multiple adjacent DEM cell elevation values are equal due to the need for the DEM to approximate the low slope with a limited set of integer values for elevation. The first derivative of the elevation surface thus becomes zero. In these cases, flow propagation is inhibited by these spurious zero-slope conditions. Here we present evidence for this "terracing effect" from 1) a mathematically defined simulated elevation model, to demonstrate the terracing effects of integer valued data, and 2) a real-world DEM where terracing must be

  4. Vehicle Detection and Classification from High Resolution Satellite Images

    Science.gov (United States)

    Abraham, L.; Sasikumar, M.

    2014-11-01

    In the past decades satellite imagery has been used successfully for weather forecasting, geographical and geological applications. Low resolution satellite images are sufficient for these sorts of applications. But the technological developments in the field of satellite imaging provide high resolution sensors which expands its field of application. Thus the High Resolution Satellite Imagery (HRSI) proved to be a suitable alternative to aerial photogrammetric data to provide a new data source for object detection. Since the traffic rates in developing countries are enormously increasing, vehicle detection from satellite data will be a better choice for automating such systems. In this work, a novel technique for vehicle detection from the images obtained from high resolution sensors is proposed. Though we are using high resolution images, vehicles are seen only as tiny spots, difficult to distinguish from the background. But we are able to obtain a detection rate not less than 0.9. Thereafter we classify the detected vehicles into cars and trucks and find the count of them.

  5. High resolution SPM imaging of organic molecules with functionalized tips

    Science.gov (United States)

    Jelínek, Pavel

    2017-08-01

    One of the most remarkable and exciting achievements in the field of scanning probe microscopy (SPM) in the last years is the unprecedented sub-molecular resolution of both atomic and electronic structures of single molecules deposited on solid state surfaces. Despite its youth, the technique has already brought many new possibilities to perform different kinds of measurements, which cannot be accomplished by other techniques. This opens new perspectives in advanced characterization of physical and chemical processes and properties of molecular structures on surfaces. Here, we discuss the history and recent progress of the high resolution imaging with a functionalized probe by means of atomic force microscopy (AFM), scanning tunnelling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS). We describe the mechanisms responsible for the high-resolution AFM, STM and IETS-STM contrast. The complexity of this technique requires new theoretical approaches, where a relaxation of the functionalized probe is considered. We emphasise the similarities of the mechanism driving high-resolution SPM with other imaging methods. We also summarise briefly significant achievements and progress in different branches. Finally we provide brief perspectives and remaining challenges of the further refinement of these high-resolution methods.

  6. High resolution magnetic imaging: MicroSQUID Force Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hasselbach, K; Ladam, C; Dolocan, V O; Hykel, D; Crozes, T [Institut Neel, CNRS et Universite Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9 (France); Schuster, K [Institut de RadioAstronomie Millimetrique 300 rue de la Piscine, Domaine Universitaire F-38406 Saint Martin d' Heres (France); Mailly, D [Laboratoire de Photonique et de Nanostructures, CNRS, Site Alcatel de Marcoussis Route de Nozay F-91460 Marcoussis (France)], E-mail: klaus.hasselbach@grenoble.cnrs.fr

    2008-02-01

    Magnetic imaging at the micrometer scale with high sensitivity is a challenge difficult to be met. Magnetic force microscopy has a very high spatial resolution but is limited in magnetic resolution. Hall probe microscopy is very powerful but sensor fabrication at the one micron scale is difficult and effects due to discreteness of charge appear in the form of significant 1/f noise. SQUID microscopy is very powerful, having high magnetic resolution, but spatial resolution is usually of the order of 10 {mu}m. The difficulties lay mostly in an efficient way to couple flux to the sensor. The only way to improve spatial resolution is to place the probe close to the very edge of the support, thus maximising coupling and spatial resolution. If there has been found a way to bring close the tip, there must be also found a reliable a way to maintain distance during scanning. We want to present recent improvements on scanning microsquid microscopy: Namely the improved fabrication of microSQUID tips using silicon micro machining and the precise positioning of the micrometer diameter microSQUID loop by electron beam lithography. The microSQUID is a microbridge DC SQUID, with two opposite microbridges. The constrictions are patterned by high-resolution e-beam lithography and have a width of 20 nm and a length of about 100 nm. The distance control during scanning is obtained by integrating the microSQUID sensor with a piezoelectric tuning fork acting as a force sensor allowing to control height and even topographic imaging. The detector is placed in a custom built near field microscope and the sample temperature can be varied between 0.1 Kelvin and 10 K. The microscope is used to study magnetic flux structures in unconventional superconductors and will be used to observe thermal domains in superconducting detectors in the voltage state.

  7. High spatial resolution diffusion tensor imaging and its applications

    CERN Document Server

    Wang, J J

    2002-01-01

    Introduction Magnetic Resonance Imaging is at present the only imaging technique available to measure diffusion of water and metabolites in humans. It provides vital insights to brain connectivity and has proved to be an important tool in diagnosis and therapy planning in many neurological diseases such as brain tumour, ischaemia and multiple sclerosis. This project focuses on the development of a high resolution diffusion tensor imaging technique. In this thesis, the basic theory of diffusion tensor MR Imaging is presented. The technical challenges encountered during development of these techniques will be discussed, with proposed solutions. New sequences with high spatial resolution have been developed and the results are compared with the standard technique more commonly used. Overview The project aims at the development of diffusion tensor imaging techniques with a high spatial resolution. Chapter 2 will describe the basic physics of MRI, the phenomenon of diffusion and the measurement of diffusion by MRI...

  8. Developing Visual Editors for High-Resolution Haptic Patterns

    DEFF Research Database (Denmark)

    Cuartielles, David; Göransson, Andreas; Olsson, Tony;

    2012-01-01

    In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit hi...... resolution haptic patterns so that they translate naturally to the user’s haptic experience. To solve this question we have developed and tested several visual editors......In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit high...

  9. A high resolution powder diffractometer using focusing optics

    Indian Academy of Sciences (India)

    V Siruguri; P D Babu; M Gupta; A V Pimpale; P S Goyal

    2008-11-01

    In this paper, we describe the design, construction and performance of a new high resolution neutron powder diffractometer that has been installed at the Dhruva reactor, Trombay, India. The instrument employs novel design concepts like the use of bent, perfect crystal monochromator and open beam geometry, enabling the use of smaller samples. The resolution curve of the instrument was found to have little variation over a wide angular region and a / ∼ 0.3% has been achieved. The instrument provides sample environment of very low temperatures and high magnetic fields using a 7 Tesla cryogen-free superconducting magnet with a VTI having a temperature range of 1.5–320 K. The special sample environment and high resolution make this neutron powder diffractometer a very powerful facility for studying magnetic properties of materials.

  10. 3 Tesla multiparametric MRI for GTV-definition of Dominant Intraprostatic Lesions in patients with Prostate Cancer – an interobserver variability study

    Science.gov (United States)

    2013-01-01

    Purpose To evaluate the interobserver variability of gross tumor volume (GTV) - delineation of Dominant Intraprostatic Lesions (DIPL) in patients with prostate cancer using published MRI criteria for multiparametric MRI at 3 Tesla by 6 different observers. Material and methods 90 GTV-datasets based on 15 multiparametric MRI sequences (T2w, diffusion weighted (DWI) and dynamic contrast enhanced (DCE)) of 5 patients with prostate cancer were generated for GTV-delineation of DIPL by 6 observers. The reference GTV-dataset was contoured by a radiologist with expertise in diagnostic imaging of prostate cancer using MRI. Subsequent GTV-delineation was performed by 5 radiation oncologists who received teaching of MRI-features of primary prostate cancer before starting contouring session. GTV-datasets were contoured using Oncentra Masterplan® and iplan® Net. For purposes of comparison GTV-datasets were imported to the Artiview® platform (Aquilab®), GTV-values and the similarity indices or Kappa indices (KI) were calculated with the postulation that a KI > 0.7 indicates excellent, a KI > 0.6 to 0.5 to < 0.6 moderate agreement. Additionally all observers rated difficulties of contouring for each MRI-sequence using a 3 point rating scale (1 = easy to delineate, 2 = minor difficulties, 3 = major difficulties). Results GTV contouring using T2w (KI-T2w = 0.61) and DCE images (KI-DCE = 0.63) resulted in substantial agreement. GTV contouring using DWI images resulted in moderate agreement (KI-DWI = 0.51). KI-T2w and KI-DCE was significantly higher than KI-DWI (p = 0.01 and p = 0.003). Degree of difficulty in contouring GTV was significantly lower using T2w and DCE compared to DWI-sequences (both p < 0.0001). Analysis of delineation differences revealed inadequate comparison of functional (DWI, DCE) to anatomical sequences (T2w) and lack of awareness of non-specific imaging findings as a source of erroneous delineation. Conclusions Using T

  11. High-resolution low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Buban, James P; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D; Stahlberg, Henning

    2010-01-01

    During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM.

  12. Novel techniques in VUV high-resolution spectroscopy

    CERN Document Server

    Ubachs, W; Eikema, K S E; de Oliveira, N; Nahon, L

    2013-01-01

    Novel VUV sources and techniques for VUV spectroscopy are reviewed. Laser-based VUV sources have been developed via non-linear upconversion of laser pulses in the nanosecond (ns), the picosecond (ps), and femtosecond (fs) domain, and are applied in high-resolution gas phase spectroscopic studies. While the ns and ps pulsed laser sources, at Fourier-transform limited bandwidths, are used in wavelength scanning spectroscopy, the fs laser source is used in a two-pulse time delayed mode. In addition a Fourier-transform spectrometer for high resolution gas-phase spectroscopic studies in the VUV is described, exhibiting the multiplex advantage to measure many resonances simultaneously.

  13. High-resolution second harmonic optical coherence tomography

    Science.gov (United States)

    Jiang, Yi; Tomov, Ivan V.; Wang, Yimin; Chen, Zhongping

    2005-04-01

    A high-resolution Second Harmonic Optical Coherence Tomography (SH-OCT) system is demonstrated using a spectrum broadened femtosecond Ti:sapphire laser. An axial resolution of 4.2 μm at the second harmonic wave center wavelength of 400 nm has been achieved. Because the SH-OCT system uses the second harmonic generation signals that strongly depend on the orientation, polarization and local symmetry properties of chiral molecules, this technique provides unique contrast enhancement to conventional optical coherence tomography. The system is applied to image biological tissues like the rat-tail tendon. Images of highly organized collagen fibrils in the rat-tail tendon have been demonstrated.

  14. Progress in high-resolution x-ray holographic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

    1987-07-01

    Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs.

  15. High-resolution EEG (HR-EEG) and magnetoencephalography (MEG).

    Science.gov (United States)

    Gavaret, M; Maillard, L; Jung, J

    2015-03-01

    High-resolution EEG (HR-EEG) and magnetoencephalography (MEG) allow the recording of spontaneous or evoked electromagnetic brain activity with excellent temporal resolution. Data must be recorded with high temporal resolution (sampling rate) and high spatial resolution (number of channels). Data analyses are based on several steps with selection of electromagnetic signals, elaboration of a head model and use of algorithms in order to solve the inverse problem. Due to considerable technical advances in spatial resolution, these tools now represent real methods of ElectroMagnetic Source Imaging. HR-EEG and MEG constitute non-invasive and complementary examinations, characterized by distinct sensitivities according to the location and orientation of intracerebral generators. In the presurgical assessment of drug-resistant partial epilepsies, HR-EEG and MEG can characterize and localize interictal activities and thus the irritative zone. HR-EEG and MEG often yield significant additional data that are complementary to other presurgical investigations and particularly relevant in MRI-negative cases. Currently, the determination of the epileptogenic zone and functional brain mapping remain rather less well-validated indications. In France, in 2014, HR-EEG is now part of standard clinical investigation of epilepsy, while MEG remains a research technique.

  16. Multi-resolution voxel phantom modeling: a high-resolution eye model for computational dosimetry

    Science.gov (United States)

    Caracappa, Peter F.; Rhodes, Ashley; Fiedler, Derek

    2014-09-01

    Voxel models of the human body are commonly used for simulating radiation dose with a Monte Carlo radiation transport code. Due to memory limitations, the voxel resolution of these computational phantoms is typically too large to accurately represent the dimensions of small features such as the eye. Recently reduced recommended dose limits to the lens of the eye, which is a radiosensitive tissue with a significant concern for cataract formation, has lent increased importance to understanding the dose to this tissue. A high-resolution eye model is constructed using physiological data for the dimensions of radiosensitive tissues, and combined with an existing set of whole-body models to form a multi-resolution voxel phantom, which is used with the MCNPX code to calculate radiation dose from various exposure types. This phantom provides an accurate representation of the radiation transport through the structures of the eye. Two alternate methods of including a high-resolution eye model within an existing whole-body model are developed. The accuracy and performance of each method is compared against existing computational phantoms.

  17. Comparison of 3D cube FLAIR with 2D FLAIR for multiple sclerosis imaging at 3 tesla

    Energy Technology Data Exchange (ETDEWEB)

    Patzig, M.; Brueckmann, H.; Fesl, G. [Muenchen Univ. (Germany). Dept. of Neuroradiology; Burke, M. [GE Healthcare, Solingen (Germany)

    2014-05-15

    Purpose: Three-dimensional (3 D) MRI sequences allow improved spatial resolution with good signal and contrast properties as well as multiplanar reconstruction. We sought to compare Cube, a 3 D FLAIR sequence, to a standard 2 D FLAIR sequence in multiple sclerosis (MS) imaging. Materials and Methods: Examinations were performed in the clinical routine on a 3.0 Tesla scanner. 12 patients with definite MS were included. Lesions with MS-typical properties on the images of Cube FLAIR and 2 D FLAIR sequences were counted and allocated to different brain regions. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated. Results: With 384 the overall number of lesions found with Cube FLAIR was significantly higher than with 2 D FLAIR (N = 221). The difference was mostly accounted for by supratentorial lesions (N = 372 vs. N = 216) while the infratentorial lesion counts were low in both sequences. SNRs and CNRs were significantly higher in CUBE FLAIR with the exception of the CNR of lesion to gray matter, which was not significantly different. Conclusion: Cube FLAIR showed a higher sensitivity for MS lesions compared to a 2 D FLAIR sequence. 3 D FLAIR might replace 2 D FLAIR sequences in MS imaging in the future. (orig.)

  18. High Resolution Simulations of Future Climate in West Africa Using a Variable-Resolution Atmospheric Model

    Science.gov (United States)

    Adegoke, J. O.; Engelbrecht, F.; Vezhapparambu, S.

    2013-12-01

    In previous work demonstrated the application of a var¬iable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM), across a wide range of spatial and time scales to investigate the ability of the model to provide realistic simulations of present-day climate and plausible projections of future climate change over sub-Saharan Africa. By applying the model in stretched-grid mode the versatility of the model dynamics, numerical formulation and physical parameterizations to function across a range of length scales over the region of interest, was also explored. We primarily used CCAM to illustrate the capability of the model to function as a flexible downscaling tool at the climate-change time scale. Here we report on additional long term climate projection studies performed by downscaling at much higher resolutions (8 Km) over an area that stretches from just south of Sahara desert to the southern coast of the Niger Delta and into the Gulf of Guinea. To perform these simulations, CCAM was provided with synoptic-scale forcing of atmospheric circulation from 2.5 deg resolution NCEP reanalysis at 6-hourly interval and SSTs from NCEP reanalysis data uses as lower boundary forcing. CCAM 60 Km resolution downscaled to 8 Km (Schmidt factor 24.75) then 8 Km resolution simulation downscaled to 1 Km (Schmidt factor 200) over an area approximately 50 Km x 50 Km in the southern Lake Chad Basin (LCB). Our intent in conducting these high resolution model runs was to obtain a deeper understanding of linkages between the projected future climate and the hydrological processes that control the surface water regime in this part of sub-Saharan Africa.

  19. High resolution spectroscopy in the microwave and far infrared

    Science.gov (United States)

    Pickett, Herbert M.

    1990-01-01

    High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

  20. High resolution map of light pollution over Poland

    Science.gov (United States)

    Netzel, Henryka; Netzel, Paweł

    2016-09-01

    In 1976 Berry introduced a simple mathematical equation to calculate artificial night sky brightness at zenith. In the original model cities, considered as points with given population, are only sources of light emission. In contrary to Berry's model, we assumed that all terrain surface can be a source of light. Emission of light depends on percent of built up area in a given cell. We based on Berry's model. Using field measurements and high-resolution data we obtained the map of night sky brightness over Poland in 100-m resolution. High resolution input data, combined with a very simple model, makes it possible to obtain detailed structures of the night sky brightness without complicating the calculations.

  1. A cloud mask methodology for high resolution remote sensing data combining information from high and medium resolution optical sensors

    Science.gov (United States)

    Sedano, Fernando; Kempeneers, Pieter; Strobl, Peter; Kucera, Jan; Vogt, Peter; Seebach, Lucia; San-Miguel-Ayanz, Jesús

    2011-09-01

    This study presents a novel cloud masking approach for high resolution remote sensing images in the context of land cover mapping. As an advantage to traditional methods, the approach does not rely on thermal bands and it is applicable to images from most high resolution earth observation remote sensing sensors. The methodology couples pixel-based seed identification and object-based region growing. The seed identification stage relies on pixel value comparison between high resolution images and cloud free composites at lower spatial resolution from almost simultaneously acquired dates. The methodology was tested taking SPOT4-HRVIR, SPOT5-HRG and IRS-LISS III as high resolution images and cloud free MODIS composites as reference images. The selected scenes included a wide range of cloud types and surface features. The resulting cloud masks were evaluated through visual comparison. They were also compared with ad-hoc independently generated cloud masks and with the automatic cloud cover assessment algorithm (ACCA). In general the results showed an agreement in detected clouds higher than 95% for clouds larger than 50 ha. The approach produced consistent results identifying and mapping clouds of different type and size over various land surfaces including natural vegetation, agriculture land, built-up areas, water bodies and snow.

  2. High-resolution TFT-LCD for spatial light modulator

    Science.gov (United States)

    Lee, JaeWon; Kim, Yong-Hae; Byun, Chun-Won; Pi, Jae-Eun; Oh, Himchan; Kim, GiHeon; Lee, Myung-Lae; Chu, Hye-Yong; Hwang, Chi-Sun

    2014-06-01

    SLM with very fine pixel pitch is needed for the holographic display system. Among various kinds of SLMs, commercially available high resolution LCoS has been widely used as a spatial light modulator. But the size of commercially available LCoS SLM is limited because the manufacturing technology of LCoS is based on the semiconductor process developed on small size Si wafer. Recently very high resolution flat panel display panel (~500ppi) was developed as a "retina display". Until now, the pixel pitch of flat panel display is several times larger than the pixel pitch of LCoS. But considering the possibility of shrink down the pixel pitch with advanced lithographic tools, the application of flat panel display will make it possible to build a SLM with high spatial bandwidth product. We simulated High resolution TFT-LCD panel on glass substrate using oxide semiconductor TFT with pixel pitch of 20um. And we considered phase modulation behavior of LC(ECB) mode. The TFT-LCD panel is reflective type with 4-metal structure with organic planarization layers. The technical challenge for high resolution large area SLM will be discussed with very fine pixel.

  3. High resolution multiplexed functional imaging in live embryos (Conference Presentation)

    Science.gov (United States)

    Xu, Dongli; Zhou, Weibin; Peng, Leilei

    2017-02-01

    Fourier multiplexed fluorescence lifetime imaging (FmFLIM) scanning laser optical tomography (FmFLIM-SLOT) combines FmFLIM and Scanning laser optical tomography (SLOT) to perform multiplexed 3D FLIM imaging of live embryos. The system had demonstrate multiplexed functional imaging of zebrafish embryos genetically express Foster Resonant Energy Transfer (FRET) sensors. However, previous system has a 20 micron resolution because the focused Gaussian beam diverges quickly from the focused plane, makes it difficult to achieve high resolution imaging over a long projection depth. Here, we present a high-resolution FmFLIM-SLOT system with achromatic Bessel beam, which achieves 3 micron resolution in 3D deep tissue imaging. In Bessel-FmFLIM-SLOT, multiple laser excitation lines are firstly intensity modulated by a Michelson interferometer with a spinning polygon mirror optical delay line, which enables Fourier multiplexed multi-channel lifetime measurements. Then, a spatial light modulator and a prism are used to transform the modulated Gaussian laser beam to an achromatic Bessel beam. The achromatic Bessel beam scans across the whole specimen with equal angular intervals as sample rotated. After tomography reconstruction and the frequency domain lifetime analysis method, both the 3D intensity and lifetime image of multiple excitation-emission can be obtained. Using Bessel-FmFLIM-SLOT system, we performed cellular-resolution FLIM tomography imaging of live zebrafish embryo. Genetically expressed FRET sensors in these embryo will allow non-invasive observation of multiple biochemical processes in vivo.

  4. Immersion Gratings for Infrared High-resolution Spectroscopy

    Science.gov (United States)

    Sarugaku, Yuki; Ikeda, Yuji; Kobayashi, Naoto; Kaji, Sayumi; Sukegawa, Takashi; Sugiyama, Shigeru; Nakagawa, Takao; Arasaki, Takayuki; Kondo, Sohei; Nakanishi, Kenshi; Yasui, Chikako; Kawakita, Hideyo

    2016-10-01

    High-resolution spectroscopy in the infrared wavelength range is essential for observations of minor isotopologues, such as HDO for water, and prebiotic organic molecules like hydrocarbons/P-bearing molecules because numerous vibrational molecular bands (including non-polar molecules) are located in this wavelength range. High spectral resolution enables us to detect weak lines without spectral line confusion. This technique has been widely used in planetary sciences, e.g., cometary coma (H2O, CO, and organic molecules), the martian atmosphere (CH4, CO2, H2O and HDO), and the upper atmosphere of gas giants (H3+ and organic molecules such as C2H6). Spectrographs with higher resolution (and higher sensitivity) still have a potential to provide a plenty of findings. However, because the size of spectrographs scales with the spectral resolution, it is difficult to realize it.Immersion grating (IG), which is a diffraction grating wherein the diffraction surface is immersed in a material with a high refractive index (n > 2), provides n times higher spectral resolution compared to a reflective grating of the same size. Because IG reduces the size of spectrograph to 1/n compared to the spectrograph with the same spectral resolution using a conventional reflective grating, it is widely acknowledged as a key optical device to realize compact spectrographs with high spectral resolution.Recently, we succeeded in fabricating a CdZnTe immersion grating with the theoretically predicted diffraction efficiency by machining process using an ultrahigh-precision five-axis processing machine developed by Canon Inc. Using the same technique, we completed a practical germanium (Ge) immersion grating with both a reflection coating on the grating surface and the an AR coating on the entrance surface. It is noteworthy that the wide wavelength range from 2 to 20 um can be covered by the two immersion gratings.In this paper, we present the performances and the applications of the immersion

  5. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

    Science.gov (United States)

    Bonutti, F; Tecchio, M; Maieron, M; Trevisan, D; Negro, C; Calligaris, F

    2016-03-01

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures.

  6. Velocity-selective magnetization-prepared non-contrast-enhanced cerebral MR angiography at 3 Tesla: Improved immunity to B0/B1 inhomogeneity.

    Science.gov (United States)

    Qin, Qin; Shin, Taehoon; Schär, Michael; Guo, Hua; Chen, Hanwei; Qiao, Ye

    2016-03-01

    To develop a Fourier-transform based velocity-selective (VS) pulse train that offers improved robustness to B0/B1 inhomogeneity for non-contrast-enhanced cerebral MR angiography (MRA) at 3 Tesla (T). VS pulse train I and II with different saturation bands are proposed to incorporate paired and phase cycled refocusing pulses. Their sensitivity to B0/B1 inhomogeneity was estimated through simulation and compared with a single refocused VS pulse train. The implementation was compared to standard time of flight (TOF) among eight healthy subjects. In contrast to single refocused VS pulse train, the simulated VS profiles from proposed pulse trains indicate much improved immunity to field inhomogeneity in the brain at 3T. Successive application of two identical VS pulse trains yields a better suppression of static tissue at the cost of 20 ∼ 30% signal loss within large vessels. Average relative contrast ratios of major cerebral arterial segments applying both pulse train I and II with two preparations are 0.81 ± 0.06 and 0.81 ± 0.05, respectively, significantly higher than 0.67 ± 0.07 of TOF-MRA. VS MRA, in particular, the pulse train II with the narrower saturation band, depicts more small vessels with slower flow. VS magnetization-prepared cerebral MRA was demonstrated among normal subjects on a 3T scanner. © 2015 Wiley Periodicals, Inc.

  7. Assessment of safety and interference issues of radio frequency identification devices in 0.3 Tesla magnetic resonance imaging and computed tomography.

    Science.gov (United States)

    Periyasamy, M; Dhanasekaran, R

    2014-01-01

    The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning.

  8. A DVD Spectroscope: A Simple, High-Resolution Classroom Spectroscope

    Science.gov (United States)

    Wakabayashi, Fumitaka; Hamada, Kiyohito

    2006-01-01

    Digital versatile disks (DVDs) have successfully made up an inexpensive but high-resolution spectroscope suitable for classroom experiments that can easily be made with common material and gives clear and fine spectra of various light sources and colored material. The observed spectra can be photographed with a digital camera, and such images can…

  9. High-resolution kinetic energy distributions via doppler shift measurements

    Science.gov (United States)

    Xu, Z.; Koplitz, B.; Buelow, S.; Baugh, D.; Wittig, C.

    1986-07-01

    In photolysis/probe experiments using pulsed sources, time delay produces both spatial and directional bias in the fragment distributions, thus enabling well-resolved kinetic energy distributions to be obtained from Doppler shift measurements. Data are presented for H-atoms detected using two-photon ionization, and high S/N and laser-limited kinetic energy resolution are demonstrated.

  10. High resolution ultraviolet imaging spectrometer for latent image analysis.

    Science.gov (United States)

    Lyu, Hang; Liao, Ningfang; Li, Hongsong; Wu, Wenmin

    2016-03-21

    In this work, we present a close-range ultraviolet imaging spectrometer with high spatial resolution, and reasonably high spectral resolution. As the transmissive optical components cause chromatic aberration in the ultraviolet (UV) spectral range, an all-reflective imaging scheme is introduced to promote the image quality. The proposed instrument consists of an oscillating mirror, a Cassegrain objective, a Michelson structure, an Offner relay, and a UV enhanced CCD. The finished spectrometer has a spatial resolution of 29.30μm on the target plane; the spectral scope covers both near and middle UV band; and can obtain approximately 100 wavelength samples over the range of 240~370nm. The control computer coordinates all the components of the instrument and enables capturing a series of images, which can be reconstructed into an interferogram datacube. The datacube can be converted into a spectrum datacube, which contains spectral information of each pixel with many wavelength samples. A spectral calibration is carried out by using a high pressure mercury discharge lamp. A test run demonstrated that this interferometric configuration can obtain high resolution spectrum datacube. The pattern recognition algorithm is introduced to analyze the datacube and distinguish the latent traces from the base materials. This design is particularly good at identifying the latent traces in the application field of forensic imaging.

  11. A Large Scale, High Resolution Agent-Based Insurgency Model

    Science.gov (United States)

    2013-09-30

    2007). HSCB Models can be employed for simulating mission scenarios, determining optimal strategies for disrupting terrorist networks, or training and...High Resolution Agent-Based Insurgency Model ∑ = ⎜ ⎜ ⎝ ⎛ − −− = desired 1 move,desired, desired,,desired, desired,, N j ij jmoveij moveiD rp prp

  12. Workshop on high-resolution, large-acceptance spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Zeidman, B. (ed.)

    1981-01-01

    The purpose of the Workshop on High-Resolution, Large-Acceptance Spectrometers was to provide a means for exchange of information among those actively engaged in the design and construction of these new spectrometers. Thirty-seven papers were prepared for the data base.

  13. Remote parallel rendering for high-resolution tiled display walls

    KAUST Repository

    Nachbaur, Daniel

    2014-11-01

    © 2014 IEEE. We present a complete, robust and simple to use hardware and software stack delivering remote parallel rendering of complex geometrical and volumetric models to high resolution tiled display walls in a production environment. We describe the setup and configuration, present preliminary benchmarks showing interactive framerates, and describe our contributions for a seamless integration of all the software components.

  14. High resolution STEM of quantum dots and quantum wires

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima

    2013-01-01

    This article reviews the application of high resolution scanning transmission electron microscopy (STEM) to semiconductor quantum dots (QDs) and quantum wires (QWRs). Different imaging and analytical techniques in STEM are introduced and key examples of their application to QDs and QWRs...

  15. Structure Identification in High-Resolution Transmission Electron Microscopic Images

    DEFF Research Database (Denmark)

    Vestergaard, Jacob Schack; Kling, Jens; Dahl, Anders Bjorholm

    2014-01-01

    A connection between microscopic structure and macroscopic properties is expected for almost all material systems. High-resolution transmission electron microscopy is a technique offering insight into the atomic structure, but the analysis of large image series can be time consuming. The present ...

  16. Signal Processing for High Resolution FMCW SAR and Moving Target

    NARCIS (Netherlands)

    Meta, A.; Hoogeboom, P.

    2005-01-01

    The combination of Frequency Modulated ContinuousWave (FMCW) technology and Synthetic Aperture Radar (SAR) leads to lightweight, cost-effective imaging sensors of high resolution. In FMCW SAR applications the conventional stop-and-go approximation used in pulse radar algorithms cannot be considered

  17. High Resolution Digital Imaging of Paintings: The Vasari Project.

    Science.gov (United States)

    Martinez, Kirk

    1991-01-01

    Describes VASARI (the Visual Art System for Archiving and Retrieval of Images), a project funded by the European Community to show the feasibility of high resolution colormetric imaging directly from paintings. The hardware and software used in the system are explained, storage on optical disks is described, and initial results are reported. (five…

  18. Ultra-high-resolution small-animal SPECT imaging

    NARCIS (Netherlands)

    Have, F. van der

    2007-01-01

    The main subject of this thesis is the development of the first two in a series of dedicated ultra-high resolution Single Photon Emission Computed Tomography (SPECT) systems (U-SPECT-I and II) for the imaging of distributions of radio-isotope labeled tracers in small laboratory animals such as mice

  19. HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    SCHOFIELD JS

    2007-10-04

    This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

  20. High resolution ultrasonography in isolated soft tissue and intramuscular cysticercosis

    Directory of Open Access Journals (Sweden)

    Gaurav Sharma

    2016-01-01

    Conclusions: With the advent of high resolution ultrasonography and increased clinical awareness of the isolated soft tissue-intramuscular cysticercosis especially in endemic zone, a more conservative non-invasive approach can be applied both in diagnosis and treatment of these isolated cases of cysticercosis. [Int J Res Med Sci 2016; 4(1.000: 42-46

  1. Development of high accuracy and resolution geoid and gravity maps

    Science.gov (United States)

    Gaposchkin, E. M.

    1986-01-01

    Precision satellite to satellite tracking can be used to obtain high precision and resolution maps of the geoid. A method is demonstrated to use data in a limited region to map the geopotential at the satellite altitude. An inverse method is used to downward continue the potential to the Earth surface. The method is designed for both satellites in the same low orbit.

  2. Systematic high-resolution assessment of global hydropower potential

    NARCIS (Netherlands)

    Hoes, Olivier A C; Meijer, Lourens J J; Van Der Ent, Ruud J.; Van De Giesen, Nick C.

    2017-01-01

    Population growth, increasing energy demand and the depletion of fossil fuel reserves necessitate a search for sustainable alternatives for electricity generation. Hydropower could replace a large part of the contribution of gas and oil to the present energy mix. However, previous high-resolution

  3. High-resolution radio imaging of young supernovae

    CERN Document Server

    Pérez-Torres, M A; Alberdi, A; Ros, E; Guirado, J C; Lara, L; Mantovani, F; Stockdale, C J; Weiler, K W; Diamond, P J; Van Dyk, S D; Lundqvist, P; Panagia, N; Shapiro, I I; Sramek, R

    2004-01-01

    The high resolution obtained through the use of VLBI gives an unique opportunity to directly observe the interaction of an expanding radio supernova with its surrounding medium. We present here results from our VLBI observations of the young supernovae SN 1979C, SN 1986J, and SN 2001gd.

  4. High energy resolution off-resonant X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wojciech, Blachucki [Univ. of Fribourg (Switzerland). Dept. of Physics

    2015-10-16

    This work treats of the high energy resolution off-resonant X-ray spectroscopy (HEROS) method of determining the density of unoccupied electronic states in the vicinity of the absorption edge. HEROS is an alternative to the existing X-ray absorption spectroscopy (XAS) methods and opens the way for new studies not achievable before.

  5. High-resolution palaeoclimatology of the last millennium

    DEFF Research Database (Denmark)

    Vinther, Bo Møllesøe; Jones, P.D.; Briffa, K.R.

    2009-01-01

    Palaeoclimatology • high-resolution • last millennium • tree rings • dendroclimatology • chronology • uncertainty • corals • ice-cores • speleothems • documentary evidence • instrumental records • varves • borehole temperature • marine sediments • composite plus scaling • CPS • climate field...

  6. Resolution of RNA using high-performance liquid chromatography

    NARCIS (Netherlands)

    Mclaughlin, L.W.; Bischoff, Rainer

    1987-01-01

    High-performance liquid chromatographic techniques can be very effective for the resolution and isolation of nucleic acids. The characteristic ionic (phosphodiesters) and hydrophobic (nucleobases) properties of RNAs can be exploited for their separation. In this respect anion-exchange and reversed-p

  7. Five Micron High Resolution MALDI Mass Spectrometry Imaging with Simple, Interchangeable, Multi-Resolution Optical System

    Science.gov (United States)

    Feenstra, Adam D.; Dueñas, Maria Emilia; Lee, Young Jin

    2017-01-01

    High-spatial resolution mass spectrometry imaging (MSI) is crucial for the mapping of chemical distributions at the cellular and subcellular level. In this work, we improved our previous laser optical system for matrix-assisted laser desorption ionization (MALDI)-MSI, from 9 μm practical laser spot size to a practical laser spot size of 4 μm, thereby allowing for 5 μm resolution imaging without oversampling. This is accomplished through a combination of spatial filtering, beam expansion, and reduction of the final focal length. Most importantly, the new laser optics system allows for simple modification of the spot size solely through the interchanging of the beam expander component. Using 10×, 5×, and no beam expander, we could routinely change between 4, 7, and 45 μm laser spot size, in less than 5 min. We applied this multi-resolution MALDI-MSI system to a single maize root tissue section with three different spatial resolutions of 5, 10, and 50 μm and compared the differences in imaging quality and signal sensitivity. We also demonstrated the difference in depth of focus between the optical systems with 10× and 5× beam expanders.

  8. Topography improvements in MEMS DMs for high-contrast, high-resolution imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop and demonstrate an innovative microfabrication process to substantially improve the surface quality achievable in high-resolution...

  9. High resolution cross strip anodes for photon counting detectors

    Science.gov (United States)

    Siegmund, O. H. W.; Tremsin, A. S.; Vallerga, J. V.; Abiad, R.; Hull, J.

    2003-05-01

    A new photon counting, imaging readout for microchannel plate sensors, the cross strip (XS) anode, has been investigated. Charge centroiding of signals detected on two orthogonal layers of sense strip sets are used to derive photon locations. The XS anode spatial resolution (<3 μm FWHM) exceeds the spatial resolution of most direct charge sensing anodes, and does so at low gain (<2×10 6). The image linearity and fidelity are high enough to resolve and map 7 μm MCP pores, offering new possibilities for astronomical and other applications.

  10. High resolution atomic force microscopy of double-stranded RNA

    Science.gov (United States)

    Ares, Pablo; Fuentes-Perez, Maria Eugenia; Herrero-Galán, Elías; Valpuesta, José M.; Gil, Adriana; Gomez-Herrero, Julio; Moreno-Herrero, Fernando

    2016-06-01

    Double-stranded (ds) RNA mediates the suppression of specific gene expression, it is the genetic material of a number of viruses, and a key activator of the innate immune response against viral infections. The ever increasing list of roles played by dsRNA in the cell and its potential biotechnological applications over the last decade has raised an interest for the characterization of its mechanical properties and structure, and that includes approaches using Atomic Force Microscopy (AFM) and other single-molecule techniques. Recent reports have resolved the structure of dsDNA with AFM at unprecedented resolution. However, an equivalent study with dsRNA is still lacking. Here, we have visualized the double helix of dsRNA under near-physiological conditions and at sufficient resolution to resolve the A-form sub-helical pitch periodicity. We have employed different high-sensitive force-detection methods and obtained images with similar spatial resolution. Therefore, we show here that the limiting factors for high-resolution AFM imaging of soft materials in liquid medium are, rather than the imaging mode, the force between the tip and the sample and the sharpness of the tip apex.Double-stranded (ds) RNA mediates the suppression of specific gene expression, it is the genetic material of a number of viruses, and a key activator of the innate immune response against viral infections. The ever increasing list of roles played by dsRNA in the cell and its potential biotechnological applications over the last decade has raised an interest for the characterization of its mechanical properties and structure, and that includes approaches using Atomic Force Microscopy (AFM) and other single-molecule techniques. Recent reports have resolved the structure of dsDNA with AFM at unprecedented resolution. However, an equivalent study with dsRNA is still lacking. Here, we have visualized the double helix of dsRNA under near-physiological conditions and at sufficient resolution to

  11. Design for a focusing high-resolution neutron crystal diffractometer

    CERN Document Server

    Ionita, I; Popovici, M; Popa, N C

    1999-01-01

    A new concept of high-resolution focusing configuration begins to be accepted as an alternative solution to the existing conventional configurations. Among the earliest work performed in this direction is that performed at the Institute for Nuclear Research, Pitesti. These results are presented below. The experimentally determined resolution properties for two focusing configurations obtained at TRIGA reactor Pitesti and at VVRS reactor Bucharest are given in order to be compared with those obtained for the conventional ones. The principles to get focusing in crystal neutron diffractometry are presented. The main characteristics for a focusing instrument are given. (author)

  12. High resolution full-spectrum water Raman lidar

    Institute of Scientific and Technical Information of China (English)

    LIU FuChao; YI Fan; JIA JingYu; ZHANG YunPeng; ZHANG ShaoDong; YU ChangMing; TAN Ying

    2012-01-01

    Knowledge of the temporal-spatial distribution of water content in atmosphere and water phase change in cloud is important for atmospheric study.For this purpose,we have developed a high resolution full-spectrum water Raman lidar that can collect Raman signals from ice,water droplets and water vapor simultaneously.A double-grating polychromator and a 32-channel photomultiplier-tube detector are used to obtain a spectral resolution of ~0.19 nm in the full Raman spectrum range of water.Preliminary observations present the water Raman spectrum characteristics of both the mixed-phase cloud and humid air under cloudless condition.

  13. High resolution polar Kerr magnetometer for nanomagnetism and nanospintronics.

    Science.gov (United States)

    Cormier, M; Ferré, J; Mougin, A; Cromières, J-P; Klein, V

    2008-03-01

    A new high resolution polar magneto-optical (MO) Kerr magnetometer, devoted to the study of nanometer sized elements with perpendicular magnetic anisotropy, is described. The unique performances of this setup in terms of sensitivity (1.2x10(-15) emu), stability (lateral drift +/-35 nm over 3 h), and resolution (laser spot full width at half maximum down to 470 nm) are demonstrated, and illustrated by Kerr hysteresis loop measurements on a unique ultrathin magnetic nanodot, and over small segments of ultranarrow magnetic tracks. Large scanning MO Kerr microscopy images were also obtained with the same performances.

  14. High-resolution axial MR imaging of tibial stress injuries

    Directory of Open Access Journals (Sweden)

    Mammoto Takeo

    2012-05-01

    Full Text Available Abstract Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries.

  15. Spatial resolution effects on the assessment of evapotranspiration in olive orchards using high resolution thermal imagery

    Science.gov (United States)

    Santos, Cristina; Zarco-Tejada, Pablo J.; Lorite, Ignacio J.; Allen, Richard G.

    2013-04-01

    The use of remote sensing techniques for estimating surface energy balance and water consumption has significantly improved the characterization of the agricultural systems by determining accurate information about crop evapotranspiration and stress, mainly for extensive crops. However the use of these methodologies for woody crops has been low due to the difficulty in the accurate characterization of these crops, mainly caused by a coarse resolution of the imagery provided by the most widely used satellites (such as Landsat 5 and 7). The coarse spatial resolution provided by these satellite sensors aggregates into a single pixel the tree crown, sunlit and shaded soil components. These surfaces can each exhibit huge differences in temperature, albedo and vegetation indexes calculated in the visible, near infrared and short-wave infrared regions. Recent studies have found that the use of energy balance approaches can provide useful results for non-homogeneous crops (Santos et al., 2012) but detailed analysis is required to determine the effect of the spatial resolution and the aggregation of the scene components in these heterogeneous canopies. In this study a comparison between different spatial resolutions has been conducted using images from Landsat 7 (with thermal resolution of 60m) and from an airborne thermal (with resolution of 80 cm) flown over olive orchards at different dates coincident with the Landsat overpass. The high resolution thermal imagery was resampled at different scales to generate images with spatial resolution ranging from 0.8 m up to 120m (thermal resolution for Landsat 5 images). The selection of the study area was made to avoid those areas with missing Landsat 7 data caused by SLC-off gaps. The selected area has a total area of around 2500 ha and is located in Southern Spain, in the province of Malaga. The selected area is mainly cultivated with olive orchards with different crop practices (rainfed, irrigated, high density, young and adult

  16. SAGA GIS based processing of spatial high resolution temperature data

    Energy Technology Data Exchange (ETDEWEB)

    Gerlitz, Lars; Bechtel, Benjamin; Kawohl, Tobias; Boehner, Juergen [Hamburg Univ. (Germany). Inst. of Geography; Zaksek, Klemen [Hamburg Univ. (Germany). Inst. of Geophysics

    2013-07-01

    Many climate change impact studies require surface and near surface temperature data with high spatial and temporal resolution. The resolution of state of the art climate models and remote sensing data is often by far to coarse to represent the meso- and microscale distinctions of temperatures. This is particularly the case for regions with a huge variability of topoclimates, such as mountainous or urban areas. Statistical downscaling techniques are promising methods to refine gridded temperature data with limited spatial resolution, particularly due to their low demand for computer capacity. This paper presents two downscaling approaches - one for climate model output and one for remote sensing data. Both are methodically based on the FOSS-GIS platform SAGA. (orig.)

  17. Overview on high-resolution ocean modeling in JAMSTEC

    Institute of Scientific and Technical Information of China (English)

    Michio Kawamiya

    2014-01-01

    In view of the importance of ocean component for representing climate change,efforts are underway to implement a high-resolution nesting model system in Model for Interdisciplinary Research on Climate (MI-ROC) for the North Pacific using the same ocean model as used in the coupled model MIROC5. By comparing double (10 km for the northwestern Pacific,50 km for the rest of the Pacific) and triple (double nesting plus 2 km resolution near Japan) nesting,it turns out that relative vorticity is drastically enhanced near Japan with 2 km resolution. It is hoped that such an elaborated nesting system will reveal detailed processes for the ocean heat uptake by,e.g.,intermediate water and mode water formation for which the“perturbed region”near Japan is the key region.

  18. Bendable X-ray Optics for High Resolution Imaging

    Science.gov (United States)

    Gubarev, M.; Ramsey, B.; Kilaru, K.; Atkins, C.; Broadway, D.

    2014-01-01

    Current state-of the-art for x-ray optics fabrication calls for either the polishing of massive substrates into high-angular-resolution mirrors or the replication of thin, lower-resolution, mirrors from perfectly figured mandrels. Future X-ray Missions will require a change in this optics fabrication paradigm in order to achieve sub-arcsecond resolution in light-weight optics. One possible approach to this is to start with perfectly flat, light-weight surface, bend it into a perfect cone, form the desired mirror figure by material deposition, and insert the resulting mirror into a telescope structure. Such an approach is currently being investigated at MSFC, and a status report will be presented detailing the results of finite element analyses, bending tests and differential deposition experiments.

  19. Advances toward high spectral resolution quantum X-ray calorimetry

    Science.gov (United States)

    Moseley, S. H.; Kelley, R. L.; Schoelkopf, R. J.; Szymkowiak, A. E.; Mccammon, D.

    1988-01-01

    Thermal detectors for X-ray spectroscopy combining high spectral resolution and quantum efficiency have been developed. These microcalorimeters measure the energy released in the absorption of a single photon by sensing the rise in temperature of a small absorbing structure. The ultimate energy resolution of such a device is limited by the thermodynamic power fluctuations in the thermal link between the calorimeter and isothermal bath and can in principle be made as low as 1 eV. The performance of a real device is degraded due to noise contributions such as excess 1/f noise in the thermistor and incomplete conversion of energy into phonons. The authors report some recent advances in thermometry, X-ray absorption and thermalization, fabrication techniques, and detector optimization in the presence of noise. These improvements have resulted in a device with a spectral resolution of 17 eV FWHM, measured at 6 keV.

  20. High Resolution Absorption Spectroscopy using Externally Dispersed Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Edelstein, J; Erskine, D J

    2005-07-06

    We describe the use of Externally Dispersed Interferometry (EDI) for high-resolution absorption spectroscopy. By adding a small fixed-delay interferometer to a dispersive spectrograph, a precise fiducial grid in wavelength is created over the entire spectrograph bandwidth. The fiducial grid interacts with narrow spectral features in the input spectrum to create a moire pattern. EDI uses the moire pattern to obtain new information about the spectra that is otherwise unavailable, thereby improving spectrograph performance. We describe the theory and practice of EDI instruments and demonstrate improvements in the spectral resolution of conventional spectrographs by a factor of 2 to 6. The improvement of spectral resolution offered by EDI can benefit space instruments by reducing spectrograph size or increasing instantaneous bandwidth.

  1. On temporal correlations in high-resolution frequency counting

    CERN Document Server

    Dunker, Tim; Rønningen, Ole Petter

    2016-01-01

    We analyze noise properties of time series of frequency data from different counting modes of a Keysight 53230A frequency counter. We use a 10 MHz reference signal from a passive hydrogen maser connected via phase-stable Huber+Suhner Sucoflex 104 cables to the reference and input connectors of the counter. We find that the high resolution gap-free (CONT) frequency counting process imposes long-term correlations in the output data, resulting in a modified Allan deviation that is characteristic of random walk phase noise. Equally important, the CONT mode results in a frequency bias. In contrast, the counter's undocumented raw continuous mode (RCON) yields unbiased frequency stability estimates with white phase noise characteristics, and of a magnitude consistent with the counter's 20 ps single-shot resolution. Furthermore, we demonstrate that a 100-point running average filter in conjunction with the RCON mode yields resolution enhanced frequency estimates with flicker phase noise characteristics. For instance,...

  2. High Resolution Software Defined Radar System for Target Detection

    Directory of Open Access Journals (Sweden)

    S. Costanzo

    2013-01-01

    Full Text Available The Universal Software Radio Peripheral USRP NI2920, a software defined transceiver so far mainly used in Software Defined Radio applications, is adopted in this work to design a high resolution L-Band Software Defined Radar system. The enhanced available bandwidth, due to the Gigabit Ethernet interface, is exploited to obtain a higher slant-range resolution with respect to the existing Software Defined Radar implementations. A specific LabVIEW application, performing radar operations, is discussed, and successful validations are presented to demonstrate the accurate target detection capability of the proposed software radar architecture. In particular, outdoor and indoor test are performed by adopting a metal plate as reference structure located at different distances from the designed radar system, and results obtained from the measured echo are successfully processed to accurately reveal the correct target position, with the predicted slant-range resolution equal to 6 m.

  3. Photoacoustic lymphatic imaging with high spatial-temporal resolution

    Science.gov (United States)

    Martel, Catherine; Yao, Junjie; Huang, Chih-Hsien; Zou, Jun; Randolph, Gwendalyn J.; Wang, Lihong V.

    2014-11-01

    Despite its critical function in coordinating the egress of inflammatory and immune cells out of tissues and maintaining fluid balance, the causative role of lymphatic network dysfunction in pathological settings is still understudied. Engineered-animal models and better noninvasive high spatial-temporal resolution imaging techniques in both preclinical and clinical studies will help to improve our understanding of different lymphatic-related pathologic disorders. Our aim was to take advantage of our newly optimized noninvasive wide-field fast-scanning photoacoustic (PA) microcopy system to coordinately image the lymphatic vasculature and its flow dynamics, while maintaining high resolution and detection sensitivity. Here, by combining the optical-resolution PA microscopy with a fast-scanning water-immersible microelectromechanical system scanning mirror, we have imaged the lymph dynamics over a large field-of-view, with high spatial resolution and advanced detection sensitivity. Depending on the application, lymphatic vessels (LV) were spectrally or temporally differentiated from blood vessels. Validation experiments were performed on phantoms and in vivo to identify the LV. Lymphatic flow dynamics in nonpathological and pathological conditions were also visualized. These results indicate that our newly developed PA microscopy is a promising tool for lymphatic-related biological research.

  4. High resolution imaging with impulse based thermoacoustic tomography

    Science.gov (United States)

    Kellnberger, Stephan; Hajiaboli, Amir; Sergiadis, George; Razansky, Daniel; Ntziachristos, Vasilis

    2011-07-01

    Existing imaging modalities like microwave- or radiofrequency (RF) induced thermoacoustic tomography systems show the potential for resolving structures deep inside tissue due to the high penetration properties of RF. However, one of the major drawbacks of existing thermoacoustic tomography systems with pulse modulated carrier frequency excitation is the compromise between efficient signal generation and attainable spatial resolution. In order to overcome limitations of conventional thermoacoustic imaging methods, we herein present and experimentally validate our novel approach towards high resolution thermoacoustic tomography. Instead of carrier-frequency amplification, we utilize ultrahigh-energy electromagnetic impulses at nanosecond duration with near-field energy coupling, thus maintaining thermoacoustic signal strength without compromising spatial resolution. Preliminary experiments on highly absorbing objects, consisting of copper wires with characteristic sizes of ~100 μm, reveal the resolution performance which yields 160 μm. Furthermore, benefits like its cost effectiveness, simplicity and compactness with the potential application in small animal imaging as well as human body imaging show that thermoacoustic tomography with impulse excitation is a promising imaging modality which has a broad range of applications.

  5. High-resolution Imaging Techniques for the Assessment of Osteoporosis

    Science.gov (United States)

    Krug, Roland; Burghardt, Andrew J.; Majumdar, Sharmila; Link, Thomas M.

    2010-01-01

    Synopsis The importance of assessing the bone’s microarchitectural make-up in addition to its mineral density in the context of osteoporosis has been emphasized in a number of publications. The high spatial resolution required to resolve the bone’s microstructure in a clinically feasible scan time is challenging. Currently, the best suited modalities meeting these requirements in vivo are high-resolution peripheral quantitative imaging (HR-pQCT) and magnetic resonance imaging (MRI). Whereas HR-pQCT is limited to peripheral skeleton regions like the wrist and ankle, MRI can also image other sites like the proximal femur but usually with lower spatial resolution. In addition Multidetector-CT has been used for high-resolution imaging of trabecular bone structure, however, the radiation dose is a limiting factor. This article provides an overview of the different modalities, technical requirements and recent developments in this emerging field. Details regarding imaging protocols as well as image post-processing methods for bone structure quantification are discussed. PMID:20609895

  6. Validation of AIRS high-resolution stratospheric temperature retrievals

    Science.gov (United States)

    Meyer, Catrin I.; Hoffmann, Lars

    2014-10-01

    This paper focuses on stratospheric temperature observations by the Atmospheric InfraRed Sounder (AIRS) aboard NASA's Aqua satellite. We validate a nine-year record (2003 - 2011) of data retrieved with a scientific retrieval processor independent from the operational processor operated by NASA. The retrieval discussed here provides stratospheric temperature profiles for each individual AIRS footprint and has nine times better horizontal sampling than the operational data provided by NASA. The high-resolution temperature data are considered optimal for for gravity wave studies. For validation the high-resolution retrieval data are compared with results from the AIRS operational Level-2 data and the ERA-Interim meteorological reanalysis. Due to the large amount of data we performed statistical comparisons of monthly zonal mean cross-sections and time series. The comparisons show that the high-resolution temperature data are in good agreement with the validation data sets. The bias in the zonal averages is mostly within ±2K. The bias reaches a maximum of 7K to ERA-Interim and 4K to the AIRS operational data at the stratopause, it is related to the different resolutions of the data sets. Variability is nearly the same in all three data sets, having maximum standard deviations around the polar vortex in the mid and upper stratosphere. The validation presented here indicates that the high-resolution temperature retrievals are well-suited for scientific studies. In particular, we expect that they will become a valuable asset for future studies of stratospheric gravity waves.

  7. The Gaia FGK Benchmark Stars - High resolution spectral library

    CERN Document Server

    Blanco-Cuaresma, S; Jofré, P; Heiter, U

    2014-01-01

    Context. An increasing number of high resolution stellar spectra is available today thanks to many past and ongoing spectroscopic surveys. Consequently, numerous methods have been developed in order to perform an automatic spectral analysis on a massive amount of data. When reviewing published results, biases arise and they need to be addressed and minimized. Aims. We are providing a homogeneous library with a common set of calibration stars (known as the Gaia FGK Benchmark Stars) that will allow to assess stellar analysis methods and calibrate spectroscopic surveys. Methods. High resolution and signal-to-noise spectra were compiled from different instruments. We developed an automatic process in order to homogenize the observed data and assess the quality of the resulting library. Results. We built a high quality library that will facilitate the assessment of spectral analyses and the calibration of present and future spectroscopic surveys. The automation of the process minimizes the human subjectivity and e...

  8. Design of UAV high resolution image transmission system

    Science.gov (United States)

    Gao, Qiang; Ji, Ming; Pang, Lan; Jiang, Wen-tao; Fan, Pengcheng; Zhang, Xingcheng

    2017-02-01

    In order to solve the problem of the bandwidth limitation of the image transmission system on UAV, a scheme with image compression technology for mini UAV is proposed, based on the requirements of High-definition image transmission system of UAV. The video codec standard H.264 coding module and key technology was analyzed and studied for UAV area video communication. Based on the research of high-resolution image encoding and decoding technique and wireless transmit method, The high-resolution image transmission system was designed on architecture of Android and video codec chip; the constructed system was confirmed by experimentation in laboratory, the bit-rate could be controlled easily, QoS is stable, the low latency could meets most applied requirement not only for military use but also for industrial applications.

  9. Automated data processing of high-resolution mass spectra

    DEFF Research Database (Denmark)

    Hansen, Michael Adsetts Edberg; Smedsgaard, Jørn

    There has been an almost explosive growth in performance and applications of Electrospray Ionization (ESI) Time of Flight (TOF) mass spectrometry, which today is one of the most efficient tools for screening of metabolites in complex bio-samples. Most efficiently ESI-MS can be used by directly...... infusion of crude extracts into the source taking advantage of the high sensitivity, high mass resolution and accuracy and the limited fragmentation. Unfortunately, there has not been a comparable development in the data processing techniques to fully exploit gain in high resolution and accuracy...... and mass axis on to a fixed one-dimensional array, we obtain a vector that can be used directly as input in multivariate statistics or library search methods. We demonstrate that both cluster- and discriminant analysis as well as PCA (and related methods) can be applied directly on mass spectra from direct...

  10. High Resolution Optical Spectra of HBC 722 after Outburst

    CERN Document Server

    Lee, Jeong-Eun; Lee, Sang-Gak; Sung, Hyun-Il; Lee, Byeong-Cheol; Sung, Hwankyung; Green, Joel D; Jeon, Young-Beom

    2011-01-01

    We report the results of our high resolution optical spectroscopic monitoring campaign ($\\lambda$ = 3800 -- 8800 A, R = 30000 -- 45000) of the new FU Orionis-type object HBC 722. We observed HBC 722 with the BOES 1.8-m telescope between 2010 November 26 and 2010 December 29 and FU Orionis itself on 2011 January 26. We detect a number of previously unreported high-resolution K I and Ca II lines beyond 7500 A. We resolve the H$\\alpha$ and Ca II line profiles into three velocity components, which we attribute to both disk and outflow. The increased accretion during outburst can heat the disk to produce the relatively narrow absorption feature and launch outflows appearing as high velocity blue and redshifted broad features.

  11. Application Research on High Resolution Radar Target Aggregation

    Directory of Open Access Journals (Sweden)

    Zhongzhi Li

    2010-11-01

    Full Text Available In high resolution radar system, the same target always has original data; so we need to merge multiple data from the same target as one target. Because of the system’s real-time requirement, we usually have to carry out target aggregation as quickly as possible. In this paper, we propose a quick target aggregation method based on clustering algorithm. The proposed method divides original data into subsets by single dimensional distance, and then merges subsets according to single dimensional distance and setdensity. At last we apply the proposed method to carry out target aggregation for airport scene surveillance radar system. Experimental result shows the proposed method has high execution efficiency and is not sensitive to noise data; it is useful for high resolution radar target aggregation.

  12. High Resolution X-ray-Induced Acoustic Tomography

    Science.gov (United States)

    Xiang, Liangzhong; Tang, Shanshan; Ahmad, Moiz; Xing, Lei

    2016-05-01

    Absorption based CT imaging has been an invaluable tool in medical diagnosis, biology, and materials science. However, CT requires a large set of projection data and high radiation dose to achieve superior image quality. In this letter, we report a new imaging modality, X-ray Induced Acoustic Tomography (XACT), which takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. A single projection X-ray exposure is sufficient to generate acoustic signals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate in all directions from their point of generation. We demonstrate the successful reconstruction of gold fiducial markers with a spatial resolution of about 350 μm. XACT reveals a new imaging mechanism and provides uncharted opportunities for structural determination with X-ray.

  13. Imaging collagen type I fibrillogenesis with high spatiotemporal resolution.

    Science.gov (United States)

    Stamov, Dimitar R; Stock, Erik; Franz, Clemens M; Jähnke, Torsten; Haschke, Heiko

    2015-02-01

    Fibrillar collagens, such as collagen type I, belong to the most abundant extracellular matrix proteins and they have received much attention over the last five decades due to their large interactome, complex hierarchical structure and high mechanical stability. Nevertheless, the collagen self-assembly process is still incompletely understood. Determining the real-time kinetics of collagen type I formation is therefore pivotal for better understanding of collagen type I structure and function, but visualising the dynamic self-assembly process of collagen I on the molecular scale requires imaging techniques offering high spatiotemporal resolution. Fast and high-speed scanning atomic force microscopes (AFM) provide the means to study such processes on the timescale of seconds under near-physiological conditions. In this study we have applied fast AFM tip scanning to study the assembly kinetics of fibrillar collagen type I nanomatrices with a temporal resolution reaching eight seconds for a frame size of 500 nm. By modifying the buffer composition and pH value, the kinetics of collagen fibrillogenesis can be adjusted for optimal analysis by fast AFM scanning. We furthermore show that amplitude-modulation imaging can be successfully applied to extract additional structural information from collagen samples even at high scan rates. Fast AFM scanning with controlled amplitude modulation therefore provides a versatile platform for studying dynamic collagen self-assembly processes at high resolution. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. High-resolution ionization detector and array of such detectors

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)

    2001-01-16

    A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.

  15. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1997-11-01

    This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

  16. High-resolution three-dimensional imaging with compress sensing

    Science.gov (United States)

    Wang, Jingyi; Ke, Jun

    2016-10-01

    LIDAR three-dimensional imaging technology have been used in many fields, such as military detection. However, LIDAR require extremely fast data acquisition speed. This makes the manufacture of detector array for LIDAR system is very difficult. To solve this problem, we consider using compress sensing which can greatly decrease the data acquisition and relax the requirement of a detection device. To use the compressive sensing idea, a spatial light modulator will be used to modulate the pulsed light source. Then a photodetector is used to receive the reflected light. A convex optimization problem is solved to reconstruct the 2D depth map of the object. To improve the resolution in transversal direction, we use multiframe image restoration technology. For each 2D piecewise-planar scene, we move the SLM half-pixel each time. Then the position where the modulated light illuminates will changed accordingly. We repeat moving the SLM to four different directions. Then we can get four low-resolution depth maps with different details of the same plane scene. If we use all of the measurements obtained by the subpixel movements, we can reconstruct a high-resolution depth map of the sense. A linear minimum-mean-square error algorithm is used for the reconstruction. By combining compress sensing and multiframe image restoration technology, we reduce the burden on data analyze and improve the efficiency of detection. More importantly, we obtain high-resolution depth maps of a 3D scene.

  17. Accelerated high-resolution photoacoustic tomography via compressed sensing

    Science.gov (United States)

    Arridge, Simon; Beard, Paul; Betcke, Marta; Cox, Ben; Huynh, Nam; Lucka, Felix; Ogunlade, Olumide; Zhang, Edward

    2016-12-01

    Current 3D photoacoustic tomography (PAT) systems offer either high image quality or high frame rates but are not able to deliver high spatial and temporal resolution simultaneously, which limits their ability to image dynamic processes in living tissue (4D PAT). A particular example is the planar Fabry-Pérot (FP) photoacoustic scanner, which yields high-resolution 3D images but takes several minutes to sequentially map the incident photoacoustic field on the 2D sensor plane, point-by-point. However, as the spatio-temporal complexity of many absorbing tissue structures is rather low, the data recorded in such a conventional, regularly sampled fashion is often highly redundant. We demonstrate that combining model-based, variational image reconstruction methods using spatial sparsity constraints with the development of novel PAT acquisition systems capable of sub-sampling the acoustic wave field can dramatically increase the acquisition speed while maintaining a good spatial resolution: first, we describe and model two general spatial sub-sampling schemes. Then, we discuss how to implement them using the FP interferometer and demonstrate the potential of these novel compressed sensing PAT devices through simulated data from a realistic numerical phantom and through measured data from a dynamic experimental phantom as well as from in vivo experiments. Our results show that images with good spatial resolution and contrast can be obtained from highly sub-sampled PAT data if variational image reconstruction techniques that describe the tissues structures with suitable sparsity-constraints are used. In particular, we examine the use of total variation (TV) regularization enhanced by Bregman iterations. These novel reconstruction strategies offer new opportunities to dramatically increase the acquisition speed of photoacoustic scanners that employ point-by-point sequential scanning as well as reducing the channel count of parallelized schemes that use detector arrays.

  18. Imaging collagen type I fibrillogenesis with high spatiotemporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Stamov, Dimitar R, E-mail: stamov@jpk.com [JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin (Germany); Stock, Erik [JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin (Germany); Franz, Clemens M [DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1a, 76131 Karlsruhe (Germany); Jähnke, Torsten; Haschke, Heiko [JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin (Germany)

    2015-02-15

    Fibrillar collagens, such as collagen type I, belong to the most abundant extracellular matrix proteins and they have received much attention over the last five decades due to their large interactome, complex hierarchical structure and high mechanical stability. Nevertheless, the collagen self-assembly process is still incompletely understood. Determining the real-time kinetics of collagen type I formation is therefore pivotal for better understanding of collagen type I structure and function, but visualising the dynamic self-assembly process of collagen I on the molecular scale requires imaging techniques offering high spatiotemporal resolution. Fast and high-speed scanning atomic force microscopes (AFM) provide the means to study such processes on the timescale of seconds under near-physiological conditions. In this study we have applied fast AFM tip scanning to study the assembly kinetics of fibrillar collagen type I nanomatrices with a temporal resolution reaching eight seconds for a frame size of 500 nm. By modifying the buffer composition and pH value, the kinetics of collagen fibrillogenesis can be adjusted for optimal analysis by fast AFM scanning. We furthermore show that amplitude-modulation imaging can be successfully applied to extract additional structural information from collagen samples even at high scan rates. Fast AFM scanning with controlled amplitude modulation therefore provides a versatile platform for studying dynamic collagen self-assembly processes at high resolution. - Highlights: • Continuous non-invasive time-lapse investigation of collagen I fibrillogenesis in situ. • Imaging of collagen I self-assembly with high spatiotemporal resolution. • Application of setpoint modulation to study the hierarchical structure of collagen I. • Observing real-time formation of the D-banding pattern in collagen I.

  19. Surgical Accuracy of 3-Tesla Versus 7-Tesla Magnetic Resonance Imaging in Deep Brain Stimulation for Parkinson Disease.

    Science.gov (United States)

    van Laar, Peter Jan; Oterdoom, D L Marinus; Ter Horst, Gert J; van Hulzen, Arjen L J; de Graaf, Eva K L; Hoogduin, Hans; Meiners, Linda C; van Dijk, J Marc C

    2016-09-01

    In deep brain stimulation (DBS), accurate placement of the lead is critical. Target definition is highly dependent on visual recognition on magnetic resonance imaging (MRI). We prospectively investigated whether the 7-T MRI enabled better visualization of targets and led to better placement of leads compared with the 1.5-T and the 3-T MRI. Three patients with PD (mean, 55 years) were scanned on 1.5-, 3-, and 7-T MRI before surgery. Tissue contrast and signal-to-noise ratio were measured. Target coordinates were noted on MRI and during surgery. Differences were analyzed with post-hoc analysis of variance. The 7-T MRI demonstrated a significant improvement in tissue visualization (P < 0.005) and signal-to-noise ratio (P < 0.005). However, no difference in the target coordinates was found between the 7-T and the 3-T MRI. Although the 7-T MRI enables a significant better visualization of the DBS target in patients with PD, we found no clinical benefit for the placement of the DBS leads. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Accuracy of 3 Tesla pelvic phased-array multiparametric MRI in diagnosing prostate cancer at repeat biopsy

    Directory of Open Access Journals (Sweden)

    Pietro Pepe

    2014-12-01

    Full Text Available Introduction. Multiparametric pelvic magnetic resonance imaging (mpMRI accuracy in prostate cancer (PCa diagnosis was evaluated. Materials and Methods. From June 2011 to December 2013, 168 patients (median 65 years with negative digital rectal examination underwent repeat transperineal saturation biopsy (SPBx; median 28 cores for persistently high or increasing PSA values, PSA >10 ng/ml or PSA values between 4.1-10 o r 2.6-4 ng/ml with free/total PSA < 25% and < 20%, respectively. All patients underwent mpMRI using a 3.0 Tesla scanner equipped with surface 16 channels phased-array coil and lesions suspicious for PCa were submitted to additional targeted biopsies. Results. A T1c PCa was found in 66 (39% cases; SPBx and mpMRI-suspicious targeted biopsy diagnosed 60 (91% and 52 (78.8% cancers missing 6 (all of the anterior zone and 14 cancers (12 and 2 of the lateral margins and anterior zone, respectively; in detail, mpMRI missed 12 (18.1% PCa charaterized by microfocal (1 positive core with greatest percentage of cancer and Gleason score equal to 5% and 6, respectively disease at risk for insignificant cancer. The diameter of the suspicious mpMRI lesion was directly correlated to the diagnosis of PCa with poor Gleason score (p < 0.05; detection rate of cancer for each suspicious mpMRI core was 35.3%. Diagnostic accuracy, sensitivity, specificity, positive and negative predictive value of mpMRI in diagnosing PCa was 75.7%, 82.5%, 71.8%, 78.9%, 87.9%, respectively. Conclusion. Multiparametric pMRI improved SPBx accuracy in diagnosing significant anterior PCa; the diameter of mpMRI suspicious lesion resulted significantly predictive of aggressive cancers.

  1. Delineation of alar ligament morphology: comparison of magnetic resonance imaging at 1.5 and 3 Tesla.

    Science.gov (United States)

    Schmidt, Peter; Mayer, Thomas E; Drescher, Robert

    2012-11-01

    Rupture of the alar and transverse ligaments due to whiplash injury can lead to upper cervical spine instability and subsequent neurological deterioration. The purpose of this study was to evaluate the normal anatomical variability of the alar ligaments in asymptomatic individuals with 3-T magnetic resonance imaging (MRI) and to compare the findings with standard 1.5-T examinations. Thirty-six participants underwent 3-T and 1.5-T MRIs. Magnetic resonance imaging findings were analyzed by classifying the alar ligaments with regard to the features detectability, signal intensity compared with muscle tissue, homogeneity, shape, spatial orientation, and symmetry. Delineation of the alar ligaments was significantly better on 3-T images, which were subjectively preferred for evaluation. The alar ligaments showed great variability. In the majority of participants, the alar ligaments were hypointense to muscle tissue, inhomogeneous, and different in shape and orientation. A statistically significantly higher number of ligaments appeared symmetric on 3-T imaging, indicating that 1.5-T imaging may underestimate the proportion of patients with normal, symmetric ligaments. This study demonstrates that high-field 3-T MRI provides better visualization of the alar ligaments compared with 1.5-T MRI. The higher signal-to-noise ratio allows detection of small signal changes. A great interindividual variety of the MRI morphology of the alar ligaments was found in participants with no history of neck trauma. Further studies with more participants are necessary to evaluate alar ligament pathologies in patients with a history of whiplash injury. Copyright 2012, SLACK Incorporated.

  2. Investigation of Parallel Radiofrequency Transmission for the Reduction of Heating in Long Conductive Leads in 3 Tesla Magnetic Resonance Imaging.

    Directory of Open Access Journals (Sweden)

    Clare E McElcheran

    Full Text Available Deep Brain Stimulation (DBS is increasingly used to treat a variety of brain diseases by sending electrical impulses to deep brain nuclei through long, electrically conductive leads. Magnetic resonance imaging (MRI of patients pre- and post-implantation is desirable to target and position the implant, to evaluate possible side-effects and to examine DBS patients who have other health conditions. Although MRI is the preferred modality for pre-operative planning, MRI post-implantation is limited due to the risk of high local power deposition, and therefore tissue heating, at the tip of the lead. The localized power deposition arises from currents induced in the leads caused by coupling with the radiofrequency (RF transmission field during imaging. In the present work, parallel RF transmission (pTx is used to tailor the RF electric field to suppress coupling effects. Electromagnetic simulations were performed for three pTx coil configurations with 2, 4, and 8-elements, respectively. Optimal input voltages to minimize coupling, while maintaining RF magnetic field homogeneity, were determined for all configurations using a Nelder-Mead optimization algorithm. Resulting electric and magnetic fields were compared to that of a 16-rung birdcage coil. Experimental validation was performed with a custom-built 4-element pTx coil. In simulation, 95-99% reduction of the electric field at the tip of the lead was observed between the various pTx coil configurations and the birdcage coil. Maximal reduction in E-field was obtained with the 8-element pTx coil. Magnetic field homogeneity was comparable to the birdcage coil for the 4- and 8-element pTx configurations. In experiment, a temperature increase of 2±0.15°C was observed at the tip of the wire using the birdcage coil, whereas negligible increase (0.2±0.15°C was observed with the optimized pTx system. Although further research is required, these initial results suggest that the concept of optimizing p

  3. Adaptive optics with pupil tracking for high resolution retinal imaging.

    Science.gov (United States)

    Sahin, Betul; Lamory, Barbara; Levecq, Xavier; Harms, Fabrice; Dainty, Chris

    2012-02-01

    Adaptive optics, when integrated into retinal imaging systems, compensates for rapidly changing ocular aberrations in real time and results in improved high resolution images that reveal the photoreceptor mosaic. Imaging the retina at high resolution has numerous potential medical applications, and yet for the development of commercial products that can be used in the clinic, the complexity and high cost of the present research systems have to be addressed. We present a new method to control the deformable mirror in real time based on pupil tracking measurements which uses the default camera for the alignment of the eye in the retinal imaging system and requires no extra cost or hardware. We also present the first experiments done with a compact adaptive optics flood illumination fundus camera where it was possible to compensate for the higher order aberrations of a moving model eye and in vivo in real time based on pupil tracking measurements, without the real time contribution of a wavefront sensor. As an outcome of this research, we showed that pupil tracking can be effectively used as a low cost and practical adaptive optics tool for high resolution retinal imaging because eye movements constitute an important part of the ocular wavefront dynamics.

  4. High-resolution SIT TV tube for subnanosecond image shuttering

    Science.gov (United States)

    Yates, G. J.; Vine, B. H.; Aeby, I.; Dunbar, D. L.; King, N. S. P.; Jaramillo, S. A.; Thayer, N. N.; Noel, B. W.

    1984-09-01

    A new ultrafast high-resolution image shutter tube with reasonable gain and shuttering efficiency has been designed and tested. The design uses a grid-gated silicon-intensified-target (SIT) image section and a high-speed focus projection and scan (FPS) vidicon read-out section in one envelope to eliminate resolution losses from external coupling. The design features low-gate-interface capacity, a high-conductivity shutter grid, and a segmented low-resistivity photocathode for optimum gating speed. Optical gate widths as short as 400 ps + or - 100 ps for full shuttering of the 25-mm-diam input window with spatial resolution as high as 15 1p/mm have been measured. Some design criteria, most of the electrical and optical performance data for several variations in the basic design, and a comparison (of several key response functions) with similarly tested 18- and 25-mm-diam proximity-focused microchannel-plate (MCP) image intensifier tubes (MCPTs) are included.

  5. Rapid parametric mapping of the longitudinal relaxation time T1 using two-dimensional variable flip angle magnetic resonance imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla.

    Science.gov (United States)

    Dieringer, Matthias A; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

    2014-01-01

    Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and

  6. High resolution MAS-NMR in combinatorial chemistry.

    Science.gov (United States)

    Shapiro, M J; Gounarides, J S

    High-resolution magic angle spinning (hr-MAS) NMR is a powerful tool for characterizing organic reactions on solid support. Because magic angle spinning reduces the line-broadening due to dipolar coupling and variations in bulk magnetic susceptibility, line widths approaching those obtained in solution-phase NMR can be obtained. The magic angle spinning method is amenable for use in conjunction with a variety of NMR-pulse sequences, making it possible to perform full-structure determinations and conformational analysis on compounds attached to a polymer support. Diffusion-weighted MAS-NMR methods such as SPEEDY (Spin-Echo-Enhanced Diffusion-Filtered Spectroscopy) can be used to remove unwanted signals from the solvent, residual reactants, and the polymer support from the MAS-NMR spectrum, leaving only those signals arising from the resin-bound product. This review will present the applications of high-resolution magic angle spinning NMR for use in combinatorial chemistry research.

  7. High resolution reservoir geological modelling using outcrop information

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Changmin; Lin Kexiang; Liu Huaibo [Jianghan Petroleum Institute, Hubei (China)] [and others

    1997-08-01

    This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

  8. Precision cosmology with time delay lenses: high resolution imaging requirements

    CERN Document Server

    Meng, Xiao-Lei; Agnello, Adriano; Auger, Matthew W; Liao, Kai; Marshall, Philip J

    2015-01-01

    Lens time delays are a powerful probe of cosmology, provided that the gravitational potential of the main deflector can be modeled with sufficient precision. Recent work has shown that this can be achieved by detailed modeling of the host galaxies of lensed quasars, which appear as "Einstein Rings" in high resolution images. We carry out a systematic exploration of the high resolution imaging required to exploit the thousands of lensed quasars that will be discovered by current and upcoming surveys with the next decade. Specifically, we simulate realistic lens systems as imaged by the Hubble Space Telescope (HST), James Webb Space Telescope (JWST), and ground based adaptive optics images taken with Keck or the Thirty Meter Telescope (TMT). We compare the performance of these pointed observations with that of images taken by the Euclid (VIS), Wide-Field Infrared Survey Telescope (WFIRST) and Large Synoptic Survey Telescope (LSST) surveys. We use as our metric the precision with which the slope $\\gamma'$ of the...

  9. HIGH AND LOW RESOLUTION TEXTURED MODELS OF COMPLEX ARCHITECTURAL SURFACES

    Directory of Open Access Journals (Sweden)

    E. K. Stathopoulou

    2012-09-01

    Full Text Available During the recent years it has become obvious that 3D technology, applied mainly with the use of terrestrial laser scanners (TLS is the most suitable technique for the complete geometric documentation of complex objects, whether they are monuments or architectural constructions in general. However, it is rather a challenging task to convert an acquired point cloud into a realistic 3D polygonal model that can simultaneously satisfy high resolution modeling and visualization demands. The aim of the visualization of a simple or complex object is to create a 3D model that best describes the reality within the computer environment. This paper is dedicated especially in the visualization of a complex object's 3D model, through high, as well as low resolution textured models. The object of interest for this study was the Almoina (Romanesque Door of the Cathedral of Valencia in Spain.

  10. Fabricating High-Resolution X-Ray Collimators

    Science.gov (United States)

    Appleby, Michael; Atkinson, James E.; Fraser, Iain; Klinger, Jill

    2008-01-01

    A process and method for fabricating multi-grid, high-resolution rotating modulation collimators for arcsecond and sub-arcsecond x-ray and gamma-ray imaging involves photochemical machining and precision stack lamination. The special fixturing and etching techniques that have been developed are used for the fabrication of multiple high-resolution grids on a single array substrate. This technology has application in solar and astrophysics and in a number of medical imaging applications including mammography, computed tomography (CT), single photon emission computed tomography (SPECT), and gamma cameras used in nuclear medicine. This collimator improvement can also be used in non-destructive testing, hydrodynamic weapons testing, and microbeam radiation therapy.

  11. High-resolution ultrasonographic findings in thyroid nodules

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sun Seob; Lee, Kwan Seh; Kim, Kun Sang; Park, Soo Soung [College of Medicine, Chung-Ang University, Seoul (Korea, Republic of)

    1985-08-15

    Ultrasonography, it's excellent ability of differentiating cystic from solid lesion and depicting detailed architecture, proved itself useful in the diagnosis of thyroid pathologies. Advanced high resolution equipment made hidden small lesion detected and finer structure clearly seen. They seemed to throw light on the histological diagnosis of thyroid diseases, especially differentiation of benignancy and malignancy. Author reviewed pictures of high-resolution ultrasonography of thyroid disease (24 cases) and correlated them with proven pathological findings. The results were as follows: 1. Multiplicity of lesion favors benignancy (4 cases). 2. Well defined margin favors benignancy (14/17), while ill defined margin favors malignancy (3/4), and lesion of no margin favors thyroiditis (3/3). 3. Surrounding halo favors benignancy (7 cases). 4. Hypoechogenicity were found in most of malignancy and thyroiditis. Cystic components in solid nodule were common findings in benign and malignant lesions. Calcification was not found in malignancy.

  12. Temperature-dependent high resolution absorption cross sections of propane

    Science.gov (United States)

    Beale, Christopher A.; Hargreaves, Robert J.; Bernath, Peter F.

    2016-10-01

    High resolution (0.005 cm-1) absorption cross sections have been measured for pure propane (C3H8). These cross sections cover the 2550-3500 cm-1 region at five temperatures (from 296 to 700 K) and were measured using a Fourier transform spectrometer and a quartz cell heated by a tube furnace. Calibrations were made by comparison to the integrated cross sections of propane from the Pacific Northwest National Laboratory. These are the first high resolution absorption cross sections of propane for the 3 μm region at elevated temperatures. The cross sections provided may be used to monitor propane in combustion environments and in astronomical sources such as the auroral regions of Jupiter, brown dwarfs and exoplanets.

  13. High and Low Resolution Textured Models of Complex Architectural Surfaces

    Science.gov (United States)

    Stathopoulou, E. K.; Valanis, A.; Lerma, J. L.; Georgopoulos, A.

    2011-09-01

    During the recent years it has become obvious that 3D technology, applied mainly with the use of terrestrial laser scanners (TLS) is the most suitable technique for the complete geometric documentation of complex objects, whether they are monuments or architectural constructions in general. However, it is rather a challenging task to convert an acquired point cloud into a realistic 3D polygonal model that can simultaneously satisfy high resolution modeling and visualization demands. The aim of the visualization of a simple or complex object is to create a 3D model that best describes the reality within the computer environment. This paper is dedicated especially in the visualization of a complex object's 3D model, through high, as well as low resolution textured models. The object of interest for this study was the Almoina (Romanesque) Door of the Cathedral of Valencia in Spain.

  14. Spatial Ensemble Postprocessing of Precipitation Forecasts Using High Resolution Analyses

    Science.gov (United States)

    Lang, Moritz N.; Schicker, Irene; Kann, Alexander; Wang, Yong

    2017-04-01

    Ensemble prediction systems are designed to account for errors or uncertainties in the initial and boundary conditions, imperfect parameterizations, etc. However, due to sampling errors and underestimation of the model errors, these ensemble forecasts tend to be underdispersive, and to lack both reliability and sharpness. To overcome such limitations, statistical postprocessing methods are commonly applied to these forecasts. In this study, a full-distributional spatial post-processing method is applied to short-range precipitation forecasts over Austria using Standardized Anomaly Model Output Statistics (SAMOS). Following Stauffer et al. (2016), observation and forecast fields are transformed into standardized anomalies by subtracting a site-specific climatological mean and dividing by the climatological standard deviation. Due to the need of fitting only a single regression model for the whole domain, the SAMOS framework provides a computationally inexpensive method to create operationally calibrated probabilistic forecasts for any arbitrary location or for all grid points in the domain simultaneously. Taking advantage of the INCA system (Integrated Nowcasting through Comprehensive Analysis), high resolution analyses are used for the computation of the observed climatology and for model training. The INCA system operationally combines station measurements and remote sensing data into real-time objective analysis fields at 1 km-horizontal resolution and 1 h-temporal resolution. The precipitation forecast used in this study is obtained from a limited area model ensemble prediction system also operated by ZAMG. The so called ALADIN-LAEF provides, by applying a multi-physics approach, a 17-member forecast at a horizontal resolution of 10.9 km and a temporal resolution of 1 hour. The performed SAMOS approach statistically combines the in-house developed high resolution analysis and ensemble prediction system. The station-based validation of 6 hour precipitation sums

  15. The Role of 3 Tesla Diffusion-Weighted Imaging in the Differential Diagnosis of Benign versus Malignant Cervical Lymph Nodes in Patients with Head and Neck Squamous Cell Carcinoma

    OpenAIRE

    Flavio Barchetti; Nicola Pranno; Guglielmo Giraldi; Alessandro Sartori; Silvia Gigli; Giovanni Barchetti; Luigi Lo Mele; Luigi Tonino Marsella

    2014-01-01

    Objective. The aim of this study was to validate the role of diffusion-weighted imaging (DWI) at 3 Tesla in the differential diagnosis between benign and malignant laterocervical lymph nodes in patients with head and neck squamous cell carcinoma (HNSCC). Materials and Methods. Before undergoing surgery, 80 patients, with biopsy proven HNSCC, underwent a magnetic resonance exam. Sensitivity (Se) and specificity (Spe) of conventional criteria and DWI in detecting laterocervical lymph node metas...

  16. High Resolution Aircraft Scanner Mapping of Geothermal and Volcanic Areas

    Energy Technology Data Exchange (ETDEWEB)

    Mongillo, M.A.; Cochrane, G.R.; Wood, C.P.; Shibata, Y.

    1995-01-01

    High spectral resolution GEOSCAN Mkll multispectral aircraft scanner imagery has been acquired, at 3-6 m spatial resolutions, over much of the Taupo Volcanic Zone as part of continuing investigations aimed at developing remote sensing techniques for exploring and mapping geothermal and volcanic areas. This study examined the 24-band: visible, near-IR (NIR), mid-IR (MIR) and thermal-IR (TIR) imagery acquired over Waiotapu geothermal area (3 m spatial resolution) and White Island volcano (6 m resolution). Results show that color composite images composed of visible and NIR wavelengths that correspond to color infrared (CIR) photographic wavelengths can be useful for distinguishing among bare ground, water and vegetation features and, in certain cases, for mapping various vegetation types. However, combinations which include an MIR band ({approx} 2.2 {micro}m) with either visible and NIR bands, or two NIR bands, are the most powerful for mapping vegetation types, water bodies, and bare and hydrothermally altered ground. Combinations incorporating a daytime TIR band with NIR and MIR bands are also valuable for locating anomalously hot features and distinguishing among different types of surface hydrothermal alteration.

  17. Pre-biopsy 3-Tesla MRI and targeted biopsy of the index prostate cancer: correlation with robot-assisted radical prostatectomy.

    Science.gov (United States)

    Patel, Uday; Dasgupta, Prokar; Challacombe, Ben; Cahill, Declan; Brown, Christian; Patel, Roshnee; Kirby, Roger

    2017-01-01

    To study whether pre-biopsy 3-Tesla prostate magnetic resonance imaging (MRI) with targeted biopsy allows accurate anatomical and oncological characterization of the index prostate tumour, and whether this translates into improved positive surgical margin (PSM) rates after radical prostatectomy. We conducted a retrospective analysis of all men (n = 201) who underwent robot-assisted radical prostatectomy (RARP) between July 2012 and July 2014. Patients were divided into a study group (n = 63) who had undergone pre-biopsy 3-Tesla MRI, followed by visual targeted and systematic prostate biopsy, and a control group (n = 138) who had undergone systematic biopsy alone. The two groups were well matched regarding patient and cancer characteristics. The primary study objective was to assess the accuracy of pre-biopsy MRI for localizing the index tumour. Secondary study objectives were to assess the accuracy of MRI in assessing the maximum tumour diameter (MTD) of the index tumour focus and accuracy of the targeted biopsy in determining the Gleason score and primary Gleason grade of the index tumour focus and whether PSMs were improved after RARP. The reference standard was whole-gland pathology of the resected prostate gland. Continuous variables and proportions were compared using the t-test and Mann-Whitney test or contingency tables, respectively. Pearson's correlation coefficient and Bland-Altman plots were used to compare measurement of MTD. The MRI accurately located the index tumour focus in 73% of patients. Accuracies, stratified according to use of the Prostate Imaging Reporting and Data System (PI-RADS) categories 5, 4 and 3, were 94, 75 and 60% respectively. Accuracies stratified according to MTD of ≤0.7, ≤1 and >1 cm were 50, 57 and 79%, respectively. There was a positive linear correlation between MRI and histological MTD (r = 0.42, 95% confidence interval [CI] 0.16-0.63; P = 0.002), but MRI generally underestimated the MTD: the mean MRI-measured MTD was 1

  18. A high resolution cavity BPM for the CLIC Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Chritin, N.; Schmickler, H.; Soby, L.; /CERN; Lunin, A.; Solyak, N.; Wendt, M.; Yakovlev, V.; /Fermilab

    2010-08-01

    In frame of the development of a high resolution BPM system for the CLIC Main Linac we present the design of a cavity BPM prototype. It consists of a waveguide loaded dipole mode resonator and a monopole mode reference cavity, both operating at 15 GHz, to be compatible with the bunch frequencies at the CLIC Test Facility. Requirements, design concept, numerical analysis, and practical considerations are discussed.

  19. High-Resolution Wind Measurements for Offshore Wind Energy Development

    Science.gov (United States)

    Nghiem, Son V.; Neumann, Gregory

    2011-01-01

    A mathematical transform, called the Rosette Transform, together with a new method, called the Dense Sampling Method, have been developed. The Rosette Transform is invented to apply to both the mean part and the fluctuating part of a targeted radar signature using the Dense Sampling Method to construct the data in a high-resolution grid at 1-km posting for wind measurements over water surfaces such as oceans or lakes.

  20. High resolution solar soft X-ray spectrometer

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fei; WANG Huan-Yu; PENG Wen-Xi; LIANG Xiao-Hua; ZHANG Chun-Lei; CAO Xue-Lei; JIANG Wei-Chun; ZHANG Jia-Yu; CUI Xing-Zhu

    2012-01-01

    A high resolution solar soft X-ray spectrometer (SOX) payload onboard a satellite is developed.A silicon drift detector (SDD) is adopted as the detector of the SOX spectrometer.The spectrometer consists of the detectors and their readout electronics,a data acquisition unit and a payload data handling unit.A ground test system is also developed to test SOX.The test results show that the design goals of the spectrometer system have been achieved.

  1. High resolution bathymetry of China seas and their surroundings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the oceanic lithospheric flexure and the worldwide bathymetric data ETOPO5, the high resolu tion bathymetry of the China seas and their surroundings is computed from altimeter derived gravity anomalies. The new bathymetry obtained by this study is higher resolution and accuracy than the widely used ETOPO5 data, mean while it shows clearly the seafioor, the tectonic characteristics and the geodynamical processes in the China seas.

  2. High-resolution x-ray photoemission spectra of silver

    DEFF Research Database (Denmark)

    Barrie, A.; Christensen, N. E.

    1976-01-01

    An electron spectrometer fitted with an x-ray monochromator for Al Kα1,2 radiation (1486.6 eV) has been used to record high-resolution x-ray photoelectron spectra for the 4d valence band as well as the 3d spin doublet in silver. The core-level spectrum has a line shape that can be described...

  3. High resolution inelastic electron scattering and nuclear structure

    Science.gov (United States)

    Blok, H. B.; Heisenberg, J. H.

    Thanks to the improved characteristics of the experimental set-up electron scattering has become an excellent tool to study the structure of the nucleus. After describing globally how the nuclear structure enters in the formalism of (e,e') reactions and how the high experimental resolution is obtained, several examples of the use of electron scattering for the study of specific nuclear structure questions are discussed.

  4. Tuberculous otitis media: findings on high-resolution CT

    Energy Technology Data Exchange (ETDEWEB)

    Lungenschmid, D. [Dept. of Radiodiagnostics, University Hospital Innsbruck (Austria)]|[Dept. of Magnetic Resonance and Spectroscopy, University Hospital of Innsbruck (Austria); Buchberger, W. [Dept. of Radiodiagnostics, University Hospital Innsbruck (Austria)]|[Dept. of Magnetic Resonance and Spectroscopy, University Hospital of Innsbruck (Austria); Schoen, G. [Dept. of Radiodiagnostics, University Hospital Innsbruck (Austria); Schoepf, R. [Radiologic Inst., Landeck (Austria); Mihatsch, T. [Dept. of Oto-Rhino-Laryngology, University Hospital of Innsbruck (Austria); Birbamer, G. [Dept. of Magnetic Resonance and Spectroscopy, University Hospital of Innsbruck (Austria); Wicke, K. [Inst. of Computed Tomography, University Hospital of Innsbruck (Austria)

    1993-12-01

    We describe two cases of tuberculous otitis media studied with high-resolution computed tomography (CT). Findings included extensive soft tissue densities with fluid levels in the tympanic cavity, the antrum, the mastoid and petrous air cells. Multifocal bony erosions and reactive bone sclerosis were seen as well. CT proved valuable for planning therapy by accurately displaying the involvement of the various structures of the middle and inner ear. However, the specific nature of the disease could only be presumed. (orig.)

  5. Fusion Experiments of HSI and High Resolution Panchromatic Imagery

    Science.gov (United States)

    2007-11-02

    map derived from the unsharpened HSI. The classification is performed with an unsupervised feature extraction using principal component analysis (PCA... Classification of Hyperspectral Data in Urban Area", P. 169-172, SPIE Vol.3502 8. R. C. Gonzalez, P. Wintz, Digital Image Processing, Addison-Wesley...MA 02420-9185 Abstract In this paper, the fusion of hyperspectral imaging (HSI) sensor data and high-resolution panchromatic imagery (HPI) is

  6. Optical alignment of high resolution Fourier transform spectrometers

    Science.gov (United States)

    Breckinridge, J. B.; Ocallaghan, F. G.; Cassie, A. G.

    1980-01-01

    Remote sensing, high resolution FTS instruments often contain three primary optical subsystems: Fore-Optics, Interferometer Optics, and Post, or Detector Optics. We discuss the alignment of a double-pass FTS containing a cat's-eye retro-reflector. Also, the alignment of fore-optics containing confocal paraboloids with a reflecting field stop which relays a field image onto a camera is discussed.

  7. A high resolution cavity BPM for the CLIC Test Facility

    CERN Document Server

    Chritin, N; Soby, L; Lunin, A; Solyak, N; Wendt, M; Yakovlev, V

    2012-01-01

    In frame of the development of a high resolution BPM system for the CLIC Main Linac we present the design of a cavity BPM prototype. It consists of a waveguide loaded dipole mode resonator and a monopole mode reference cavity, both operating at 15 GHz, to be compatible with the bunch frequencies at the CLIC Test Facility. Requirements, design concept, numerical analysis, and practical considerations are discussed.

  8. Chronic pneumonitis of infancy: high-resolution CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Oeystein E.; Owens, Catherine M. [Radiology Department, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, WC1N 3JH, London (United Kingdom); Sebire, Neil J. [Histopathology Department, Great Ormond Street Hospital for Children NHS Trust, London (United Kingdom); Jaffe, Adam [Portex Respiratory Medicine Unit, The Institute of Child Health, University College London, London (United Kingdom)

    2004-01-01

    Chronic pneumonitis of infancy (CPI) is a very rare entity. We report the chest radiography and high-resolution CT (HRCT) findings in an infant with histopathologically confirmed CPI. The child was admitted for intensive care 18 h after birth and died at 39 days of age. On HRCT there was diffuse ground-glass change, interlobular septal thickening and discrete centrilobular nodules. An accurate diagnosis is crucial for correct management; however, several entities with the same HRCT findings are recognized. (orig.)

  9. High-resolution CT of lesions of the optic nerve

    Energy Technology Data Exchange (ETDEWEB)

    Peyster, R.G.; Hoover, E.D.; Hershey, B.L.; Haskin, M.E.

    1983-05-01

    The optic nerves are well demonstrated by high-resolution computed tomography. Involvement of the optic nerve by optic gliomas and optic nerve sheath meningiomas is well known. However, nonneoplastic processes such as increased intracranial pressure, optic neuritis, Grave ophthalmopathy, and orbital pseudotumor may also alter the appearance of the optic nerve/sheath on computed tomography. Certain clinical and computed tomographic features permit distinction of these nonneoplastic tumefactions from tumors.

  10. Yeast expression proteomics by high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Walther, Tobias C; Olsen, Jesper Velgaard; Mann, Matthias

    2010-01-01

    -translational controls contribute majorly to regulation of protein abundance, for example in heat shock stress response. The development of new sample preparation methods, high-resolution mass spectrometry and novel bioinfomatic tools close this gap and allow the global quantitation of the yeast proteome under different...... conditions. Here, we provide background information on proteomics by mass-spectrometry and describe the practice of a comprehensive yeast proteome analysis....

  11. Progress Toward A Very High Angular Resolution Imaging Spectrometer (VERIS)

    Science.gov (United States)

    Korendyke, Clarence M.; Vourlidas, A.; Landi, E.; Seely, J.; Klimchuck, J.

    2007-07-01

    Recent imaging at arcsecond (TRACE) and sub-arcsecond (VAULT) spatial resolution clearly show that structures with fine spatial scales play a key role in the physics of the upper solar atmosphere. Both theoretical and observational considerations point to the importance of small spatial scales, impulsive energy release, strong dynamics, and extreme plasma nonuniformity. Fundamental questions regarding the nature, structure, properties and dynamics of loops and filamentary structures in the upper atmosphere have been raised. To address these questions, we are developing a next generation, VEry high angular Resolution Imaging Spectrometer (VERIS) as a sounding rocket instrument. VERIS will obtain the necessary high spatial resolution, high fidelity measurements of plasma temperatures, densities and velocities. With broad simultaneous temperature coverage, the VERIS observations will directly address unresolved issues relating to interconnections of various temperature solar plasmas. VERIS will provide the first ever subarcsecond spectra of transition region and coronal structures. It will do so with a sufficient spectral resolution of to allow centroided Doppler velocity determinations to better than 3 km/s. VERIS uses a novel two element, normal incidence optical design with highly reflective EUV coatings to access a spectral range with broad temperature coverage (0.03-15 MK) and density-sensitive line ratios. Finally, in addition to the spectra, VERIS will simultaneously obtain spectrally pure slot images (10x150 arcsec) in the +/-1 grating orders, which can be combined to make instantaneous line-of-sight velocity maps with 8km/s accuracy over an unprecedented field of view. The VERIS program is beginning the second year of its three year development cycle. All design activities and reviews are complete. Fabrication of all major components has begun. Brassboard electronics cards have been fabricated, assembled and tested. The paper presents the essential scientific

  12. High Spectral Resolution, High Cadence, Imaging X-ray Microcalorimeters for Solar Physics - Phase 2 Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcalorimeter x-ray instruments are non-dispersive, high spectral resolution, broad-band, high cadence imaging spectrometers. We have been developing these...

  13. A high-resolution record of Greenland mass balance

    Science.gov (United States)

    McMillan, Malcolm; Leeson, Amber; Shepherd, Andrew; Briggs, Kate; Armitage, Thomas W. K.; Hogg, Anna; Kuipers Munneke, Peter; Broeke, Michiel; Noël, Brice; Berg, Willem Jan; Ligtenberg, Stefan; Horwath, Martin; Groh, Andreas; Muir, Alan; Gilbert, Lin

    2016-07-01

    We map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat-2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011-2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high-resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance.

  14. High resolution ultrasonic spectroscopy system for nondestructive evaluation

    Science.gov (United States)

    Chen, C. H.

    1991-01-01

    With increased demand for high resolution ultrasonic evaluation, computer based systems or work stations become essential. The ultrasonic spectroscopy method of nondestructive evaluation (NDE) was used to develop a high resolution ultrasonic inspection system supported by modern signal processing, pattern recognition, and neural network technologies. The basic system which was completed consists of a 386/20 MHz PC (IBM AT compatible), a pulser/receiver, a digital oscilloscope with serial and parallel communications to the computer, an immersion tank with motor control of X-Y axis movement, and the supporting software package, IUNDE, for interactive ultrasonic evaluation. Although the hardware components are commercially available, the software development is entirely original. By integrating signal processing, pattern recognition, maximum entropy spectral analysis, and artificial neural network functions into the system, many NDE tasks can be performed. The high resolution graphics capability provides visualization of complex NDE problems. The phase 3 efforts involve intensive marketing of the software package and collaborative work with industrial sectors.

  15. Multimodal microscopy with high resolution spectral focusing CARS

    Science.gov (United States)

    Baldacchini, Tommaso; Zadoyan, Ruben

    2014-02-01

    In this work we describe a device that extends capabilities of multiphoton microscopes based on dual wavelength output femtosecond laser sources. CARS with 17cm-1 spectral resolution is experimentally demonstrated. Our approach is based on spectral focusing CARS. For pulse shaping of the pump and Stokes beams we utilize transmission gratings based stretcher. It allows the dispersion of the stretcher to be continuously adjusted in wide range. The best spectral resolution is achieved when the chirp rates in both pump and Stokes beam are matched. The device is automated. Any change in the beam path lengths due to the stretcher adjustment or wavelength tuning is compensated by the delay line. We incorporated into the device a computer controlled beam pointing stabilization system that compensates the beam pointing deviation due to dispersion in the system. High level of automation and computer control makes the operation of the device easy. We present CARS images of several samples that demonstrate high spectral resolution, high contrast and chemical selectivity.

  16. Development of a high resolution module for PET scanners

    Science.gov (United States)

    Stringhini, G.; Pizzichemi, M.; Ghezzi, A.; Stojkovic, A.; Tavernier, S.; Niknejad, T.; Varela, J.; Paganoni, M.; Auffray, E.

    2017-02-01

    Positron Emission Tomography (PET) scanners require high performances in term of spatial resolution and sensitivity to allow early detection of cancer masses. In small animal and organ dedicated PET scanners the Depth of Interaction (DOI) information has to be obtained to avoid parallax errors and to reconstruct high resolution images. In the whole body PET, the DOI information can be useful to correct for the time jitter of the optical photons along the main axis of the scintillator, improving the time performances. In this work we present the development of PET module designed to reach high performance as compared to the current scanners while keeping the complexity of the system reasonably low. The module presented is based on a 64 LYSO (Lutetium-yttrium oxyorthosilicate) crystals matrix and on a 4×4 MPPC (Multi Pixels Photon Counter) array as detector in a 4 to 1 coupling between the crystals and the detector and a single side readout. The lateral surfaces of the crystals are optically treated to be unpolished. The DOI and the energy resolution of the PET module are presented and a fast method to obtain the DOI calibration is discussed.

  17. High resolution, large dynamic range field map estimation

    Science.gov (United States)

    Dagher, Joseph; Reese, Timothy; Bilgin, Ali

    2013-01-01

    Purpose We present a theory and a corresponding method to compute high resolution field maps over a large dynamic range. Theory and Methods We derive a closed-form expression for the error in the field map value when computed from two echoes. We formulate an optimization problem to choose three echo times which result in a pair of maximally distinct error distributions. We use standard field mapping sequences at the prescribed echo times. We then design a corresponding estimation algorithm which takes advantage of the optimized echo times to disambiguate the field offset value. Results We validate our method using high resolution images of a phantom at 7T. The resulting field maps demonstrate robust mapping over both a large dynamic range, and in low SNR regions. We also present high resolution offset maps in vivo using both, GRE and MEGE sequences. Even though the proposed echo time spacings are larger than the well known phase aliasing cutoff, the resulting field maps exhibit a large dynamic range without the use of phase unwrapping or spatial regularization techniques. Conclusion We demonstrate a novel 3-echo field map estimation method which overcomes the traditional noise-dynamic range trade-off. PMID:23401245

  18. High Resolution CO Observations of Massive Star Forming Regions

    CERN Document Server

    Klaassen, P D; Keto, E R; Zhang, Q; Galván-Madrid, R; Liu, H-Y B

    2011-01-01

    Context. To further understand the processes involved in the formation of massive stars, we have undertaken a study of the gas dynamics surrounding three massive star forming regions. By observing the large scale structures at high resolution, we are able to determine properties such as driving source, and spatially resolve the bulk dynamical properties of the gas such as infall and outflow. Aims. With high resolution observations, we are able to determine which of the cores in a cluster forming massive stars is responsible for the large scale structures. Methods. We present CO observations of three massive star forming regions with known HII regions and show how the CO traces both infall and outflow. By combining data taken in two SMA configurations with JCMT observations, we are able to see large scale structures at high resolution. Results. We find large (0.26-0.40 pc), massive (2-3 M_sun) and energetic (13-17 \\times 10^44 erg) outflows emanating from the edges of two HII regions suggesting they are being ...

  19. High resolution, MRI-based, segmented, computerized head phantom

    Energy Technology Data Exchange (ETDEWEB)

    Zubal, I.G.; Harrell, C.R.; Smith, E.O.; Smith, A.L.; Krischlunas, P. [Yale Univ., New Haven, CT (United States). Dept. of Diagnostic Radiology

    1999-01-01

    The authors have created a high-resolution software phantom of the human brain which is applicable to voxel-based radiation transport calculations yielding nuclear medicine simulated images and/or internal dose estimates. A software head phantom was created from 124 transverse MRI images of a healthy normal individual. The transverse T2 slices, recorded in a 256x256 matrix from a GE Signa 2 scanner, have isotropic voxel dimensions of 1.5 mm and were manually segmented by the clinical staff. Each voxel of the phantom contains one of 62 index numbers designating anatomical, neurological, and taxonomical structures. The result is stored as a 256x256x128 byte array. Internal volumes compare favorably to those described in the ICRP Reference Man. The computerized array represents a high resolution model of a typical human brain and serves as a voxel-based anthropomorphic head phantom suitable for computer-based modeling and simulation calculations. It offers an improved realism over previous mathematically described software brain phantoms, and creates a reference standard for comparing results of newly emerging voxel-based computations. Such voxel-based computations lead the way to developing diagnostic and dosimetry calculations which can utilize patient-specific diagnostic images. However, such individualized approaches lack fast, automatic segmentation schemes for routine use; therefore, the high resolution, typical head geometry gives the most realistic patient model currently available.

  20. High-Resolution CH Observations of Two Translucent Molecular Clouds

    Science.gov (United States)

    Chastain, Raymond J.; Cotten, David; Magnani, Loris

    2010-01-01

    We present high-resolution (1farcm3 × 1farcm6) observations of the CH 2Π1/2 (F = 1-1) emission line at 3335 MHz in two high-latitude translucent clouds, MBM 3 and 40. At the assumed cloud distances, the angular resolution corresponds to ~0.05 pc, nearly an order of magnitude better than previous studies. Comparisons of the CH emission with previously obtained CO(1-0) data are difficult to interpret: the CO and CH line emission correlates in MBM 40 but not in MBM 3. In both clouds, there is a spatial offset in the peak emission, and perhaps in velocity for MBM 40. The difference in emission characteristics for the two tracers are noticeable in these two nearby clouds because of the high spatial resolution. Since both CH and CO are deemed to be reliable tracers of H2, our results indicate that more care should be taken when using one of these tracers to determine the mass of a nearby molecular cloud.

  1. Measurement of coronary flow response to cold pressor stress in asymptomatic women with cardiovascular risk factors using spiral velocity-encoded cine MRI at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Maroules, Christopher D.; Peshock, Ronald M. (Dept. of Radiology, Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)), e-mail: Ron.Peshock@UTSouthwestern.edu; Chang, Alice Y.; Kontak, Andrew (Dept. of Internal Medicine, Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)); Dimitrov, Ivan; Kotys, Melanie (Dept. of Philips Medical Systems, Cleveland, OH (United States))

    2010-05-15

    Background: Coronary sinus (CS) flow in response to a provocative stress has been used as a surrogate measure of coronary flow reserve, and velocity-encoded cine (VEC) magnetic resonance imaging (MRI) is an established technique for measuring CS flow. In this study, the cold pressor test (CPT) was used to measure CS flow response because it elicits an endothelium-dependent coronary vasodilation that may afford greater sensitivity for detecting early changes in coronary endothelial function. Purpose: To investigate the feasibility and reproducibility of CS flow reactivity (CSFR) to CPT using spiral VEC MRI at 3 Tesla in a sample of asymptomatic women with cardiovascular risk factors. Material and Methods: Fourteen asymptomatic women (age 38 years +- 10) with cardiovascular risk factors were studied using 3D spiral VEC MRI of the CS at 3 T. The CPT was utilized as a provocative stress to measure changes in CS flow. CSFR to CPT was calculated from the ratio of CS flow during peak stress to baseline CS flow. Results: CPT induced a significant hemodynamic response as measured by a 45% increase in rate-pressure product (P<0.01). A significant increase in CS volume flow was also observed (baseline, 116 +- 26 ml/min; peak stress, 152 +- 34 ml/min, P=0.01). CSFR to CPT was 1.31 +- 0.20. Test-retest variability of CS volume flow was 5% at baseline and 6% during peak stress. Conclusion: Spiral CS VEC MRI at 3 T is a feasible and reproducible technique for measuring CS flow in asymptomatic women at risk for cardiovascular disease. Significant changes in CSFR to CPT are detectable, without demanding pharmacologic stress

  2. Comparison of increased venous contrast in ischemic stroke using phase-sensitive MR imaging with perfusion changes on flow-sensitive alternating inversion recovery at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Eijiro; Kanasaki, Yoshiko; Fujii, Shinya; Ogawa, Toshihide (Div. of Radiology, Dept. of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori Univ. Hospital, Yonago, Tottori (Japan)), email: eyamashi-ttr@umin.ac.jp; Tanaka, Takuro; Hirata, Yoshiharu (Div. of Clinical Radiology, Tottori Univ. Hospital, Yonago, Tottori (Japan))

    2011-10-15

    Background Increased venous contrast in ischemic stroke using susceptibility-weighted imaging has been widely reported, although few reports have compared increased venous contrast areas with perfusion change areas. Purpose To compare venous contrast on phase-sensitive MR images (PSI) with perfusion change on flow-sensitive alternating inversion recovery (FAIR) images, and to discuss the clinical use of PSI in ischemic stroke. Material and Methods Thirty patients with clinically suspected acute infarction of the middle cerebral artery (MCA) territory within 7 days of onset were evaluated. Phase-sensitive imaging (PSI), flow-sensitive alternating inversion recovery (FAIR), diffusion-weighted imaging (DWI) and magnetic resonance angiography (MRA) were obtained using 3 Tesla scanner. Two neuroradiologists independently reviewed the MR images, as well as the PSI, DWI, and FAIR images. They were blinded to the clinical data and to each other's findings. The abnormal area of each image was ultimately identified after both neuroradiologists reached consensus. We analyzed areas of increased venous contrast on PSI, perfusion changes on FAIR images and signal changes on DWI for each case. Results Venous contrast increased on PSI and hypoperfusion was evident on FAIR images from 22 of the 30 patients (73%). The distribution of the increased venous contrast was the same as that of the hypoperfused areas on FAIR images in 16 of these 22. The extent of these lesions was larger than that of lesions visualized by on DWI in 18 of the 22 patients. Hypointense signals reflecting hemorrhage and no increased venous contrast on PSI and hyperperfusion on FAIR images were found in six of the remaining eight patients (20%). Findings on PSI were normal and hypoperfusion areas were absent on FAIR images of two patients (7%). Conclusion Increased venous contrast on PSI might serve as an index of misery perfusion and provide useful information

  3. An investigation into potential gender-specific differences in myocardial triglyceride content assessed by 1H-Magnetic Resonance Spectroscopy at 3Tesla.

    Science.gov (United States)

    Petritsch, Bernhard; Köstler, Herbert; Gassenmaier, Tobias; Kunz, Andreas S; Bley, Thorsten A; Horn, Michael

    2016-06-01

    Over the past decade, myocardial triglyceride content has become an accepted biomarker for chronic metabolic and cardiac disease. The purpose of this study was to use proton (hydrogen 1)-magnetic resonance spectroscopy ((1)H-MRS) at 3Tesla (3 T) field strength to assess potential gender-related differences in myocardial triglyceride content in healthy individuals. Cardiac MR imaging was performed to enable accurate voxel placement and obtain functional and morphological information. Double triggered (i.e., ECG and respiratory motion gating) (1)H-MRS was used to quantify myocardial triglyceride levels for each gender. Two-sample t-test and Mann-Whitney U-test were used for statistical analyses. In total, 40 healthy volunteers (22 male, 18 female; aged >18 years and age matched) were included in the study. Median myocardial triglyceride content was 0.28% (interquartile range [IQR] 0.17-0.42%) in male and 0.24% (IQR 0.14-0.45%) in female participants, and no statistically significant difference was observed between the genders. Furthermore, no gender-specific difference in ejection fraction was observed, although on average, male participants presented with a higher mean ± SD left ventricular mass (136.3 ± 25.2 g) than female participants (103.9 ± 16.1 g). The study showed that (1)H-MRS is a capable, noninvasive tool for acquisition of myocardial triglyceride metabolites. Myocardial triglyceride concentration was shown to be unrelated to gender in this group of healthy volunteers. © The Author(s) 2016.

  4. The Impact of Horizontal and Temporal Resolution on Convection and Precipitation with High-Resolution GEOS-5

    Science.gov (United States)

    Putman, William P.

    2012-01-01

    Using a high-resolution non-hydrostatic version of GEOS-5 with the cubed-sphere finite-volume dynamical core, the impact of spatial and temporal resolution on cloud properties will be evaluated. There are indications from examining convective cluster development in high resolution GEOS-5 forecasts that the temporal resolution within the model may playas significant a role as horizontal resolution. Comparing modeled convective cloud clusters versus satellite observations of brightness temperature, we have found that improved. temporal resolution in GEOS-S accounts for a significant portion of the improvements in the statistical distribution of convective cloud clusters. Using satellite simulators in GEOS-S we will compare the cloud optical properties of GEOS-S at various spatial and temporal resolutions with those observed from MODIS. The potential impact of these results on tropical cyclone formation and intensity will be examined as well.

  5. High Resolution Real Time Sonography of the Thyroid Gland

    Directory of Open Access Journals (Sweden)

    A. Honarbakhsh

    2008-01-01

    Full Text Available Background/Objective: High-resolution sonography equipment permits for visualization of normal and abnormal thyroid gland with or without gel pad or water bath. This study prospectively presents surgically and pathologically proved patients with thyroid disease by direct ultrasound with or without Doppler (pulse, color, power Doppler."nPatients and Methods: This study was performed by 7.5-10 MHz frequency linear probe transducer with axial resolution of 0.7mm and lateral resolution of 1-2 mm (Aloka 650 and super SG 140 Toshiba unit assembly with color, power Doppler. Patient's neck was extended as a supine position."nResults: Pathologic proof was obtained in 45 patients with benign and five patients with malignant thyroid disease. Benign lesions were follicular adenoma in 30 patients, goiter in 10 patients, as hashimoto thyroiditis in two patients, hemorrhagic cyst in two patients and simple cyst in one patient. Malignant lesions were follicular, papillary, and medulary carcinoma which seen in two, two, and one patients respectively. Echopatterns were as follow: Most of them showed decreades echo when we compare to normal thyroid tissue, some malignant lesions showed increased echo and some isoecho, in the last group we need other work up for example Doppler (pulse, color, power for evaluation vascularity. We did not have metastasis to thyroid gland."nConclusion: With advace in technology in crystal and design overall probe as a result creat broadband width probe and also full digital sonography unit inclding (beam forming - CPU in images resolution is with high grade than semi digital unit that before used for thytoid gland. When With any reason resolution is increased we sould be able to diagnosed very small and smallest lesion (for example mest to thyroid or reccurency after total Lobectomy: there is three primay uses of sonography, 1 detection of mutionodular gland when only one nodule is suspected clinically and by isotop scan.2 High

  6. High resolution modeling of a small urban catchment

    Science.gov (United States)

    Skouri-Plakali, Ilektra; Ichiba, Abdellah; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2016-04-01

    Flooding is one of the most complex issues that urban environments have to deal with. In France, flooding remains the first natural risk with 72% of decrees state of natural disaster issued between October 1982 and mid-November 2014. Flooding is a result of meteorological extremes that are usually aggravated by the hydrological behavior of urban catchments and human factors. The continuing urbanization process is indeed changing the whole urban water cycle by limiting the infiltration and promoting runoff. Urban environments are very complex systems due to their extreme variability, the interference between human activities and natural processes but also the effect of the ongoing urbanization process that changes the landscape and hardly influences their hydrologic behavior. Moreover, many recent works highlight the need to simulate all urban water processes at their specific temporal and spatial scales. However, considering urban catchments heterogeneity still challenging for urban hydrology, even after advances noticed in term of high-resolution data collection and computational resources. This issue is more to be related to the architecture of urban models being used and how far these models are ready to take into account the extreme variability of urban catchments. In this work, high spatio-temporal resolution modeling is performed for a small and well-equipped urban catchment. The aim of this work is to identify urban modeling needs in terms of spatial and temporal resolution especially for a very small urban area (3.7 ha urban catchment located in the Perreux-sur-Marne city at the southeast of Paris) MultiHydro model was selected to carry out this work, it is a physical based and fully distributed model that interacts four existing modules each of them representing a portion of the water cycle in urban environments. MultiHydro was implemented at 10m, 5m and 2m resolution. Simulations were performed at different spatio-temporal resolutions and analyzed with

  7. Distributed Modeling with Parflow using High Resolution LIDAR Data

    Science.gov (United States)

    Barnes, M.; Welty, C.; Miller, A. J.

    2012-12-01

    Urban landscapes provide a challenging domain for the application of distributed surface-subsurface hydrologic models. Engineered water infrastructure and altered topography influence surface and subsurface flow paths, yet these effects are difficult to quantify. In this work, a parallel, distributed watershed model (ParFlow) is used to simulate urban watersheds using spatial data at the meter and sub-meter scale. An approach using GRASS GIS (Geographic Resources Analysis Support System) is presented that incorporates these data to construct inputs for the ParFlow simulation. LIDAR topography provides the basis for the fully coupled overland flow simulation. Methods to address real discontinuities in the urban land-surface for use with the grid-based kinematic wave approximation used in ParFlow are presented. The spatial distribution of impervious surface is delineated accurately from high-resolution land cover data; hydrogeological properties are specified from literature values. An application is presented for part of the Dead Run subwatershed of the Gwynns Falls in Baltimore County, MD. The domain is approximately 3 square kilometers, and includes a highly impacted urban stream, a major freeway, and heterogeneous urban development represented at a 10-m horizontal resolution and 1-m vertical resolution. This resolution captures urban features such as building footprints and highways at an appropriate scale. The Dead Run domain provides an effective test case for ParFlow application at the fine scale in an urban environment. Preliminary model runs employ a homogeneous subsurface domain with no-flow boundaries. Initial results reflect the highly articulated topography of the road network and the combined influence of surface runoff from impervious surfaces and subsurface flux toward the channel network. Subsequent model runs will include comparisons of the coupled surface-subsurface response of alternative versions of the Dead Run domain with and without impervious

  8. High resolution OCT image generation using super resolution via sparse representation

    Science.gov (United States)

    Asif, Muhammad; Akram, Muhammad Usman; Hassan, Taimur; Shaukat, Arslan; Waqar, Razi

    2017-02-01

    In this paper we propose a technique for obtaining a high resolution (HR) image from a single low resolution (LR) image -using joint learning dictionary - on the basis of image statistic research. It suggests that with an appropriate choice of an over-complete dictionary, image patches can be well represented as a sparse linear combination. Medical imaging for clinical analysis and medical intervention is being used for creating visual representations of the interior of a body, as well as visual representation of the function of some organs or tissues (physiology). A number of medical imaging techniques are in use like MRI, CT scan, X-rays and Optical Coherence Tomography (OCT). OCT is one of the new technologies in medical imaging and one of its uses is in ophthalmology where it is being used for analysis of the choroidal thickness in the eyes in healthy and disease states such as age-related macular degeneration, central serous chorioretinopathy, diabetic retinopathy and inherited retinal dystrophies. We have proposed a technique for enhancing the OCT images which can be used for clearly identifying and analyzing the particular diseases. Our method uses dictionary learning technique for generating a high resolution image from a single input LR image. We train two joint dictionaries, one with OCT images and the second with multiple different natural images, and compare the results with previous SR technique. Proposed method for both dictionaries produces HR images which are comparatively superior in quality with the other proposed method of SR. Proposed technique is very effective for noisy OCT images and produces up-sampled and enhanced OCT images.

  9. High Resolution Continuous Flow Analysis System for Polar Ice Cores

    Science.gov (United States)

    Dallmayr, Remi; Azuma, Kumiko; Yamada, Hironobu; Kjær, Helle Astrid; Vallelonga, Paul; Azuma, Nobuhiko; Takata, Morimasa

    2014-05-01

    In the last decades, Continuous Flow Analysis (CFA) technology for ice core analyses has been developed to reconstruct the past changes of the climate system 1), 2). Compared with traditional analyses of discrete samples, a CFA system offers much faster and higher depth resolution analyses. It also generates a decontaminated sample stream without time-consuming sample processing procedure by using the inner area of an ice-core sample.. The CFA system that we have been developing is currently able to continuously measure stable water isotopes 3) and electrolytic conductivity, as well as to collect discrete samples for the both inner and outer areas with variable depth resolutions. Chemistry analyses4) and methane-gas analysis 5) are planned to be added using the continuous water stream system 5). In order to optimize the resolution of the current system with minimal sample volumes necessary for different analyses, our CFA system typically melts an ice core at 1.6 cm/min. Instead of using a wire position encoder with typical 1mm positioning resolution 6), we decided to use a high-accuracy CCD Laser displacement sensor (LKG-G505, Keyence). At the 1.6 cm/min melt rate, the positioning resolution was increased to 0.27mm. Also, the mixing volume that occurs in our open split debubbler is regulated using its weight. The overflow pumping rate is smoothly PID controlled to maintain the weight as low as possible, while keeping a safety buffer of water to avoid air bubbles downstream. To evaluate the system's depth-resolution, we will present the preliminary data of electrolytic conductivity obtained by melting 12 bags of the North Greenland Eemian Ice Drilling (NEEM) ice core. The samples correspond to different climate intervals (Greenland Stadial 21, 22, Greenland Stadial 5, Greenland Interstadial 5, Greenland Interstadial 7, Greenland Stadial 8). We will present results for the Greenland Stadial -8, whose depths and ages are between 1723.7 and 1724.8 meters, and 35.520 to

  10. Precision glass molding of high-resolution diffractive optical elements

    Science.gov (United States)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans P.; Plöger, Sven; Hermerschmidt, Andreas

    2016-04-01

    The demand of high resolution diffractive optical elements (DOE) is growing. Smaller critical dimensions allow higher deflection angles and can fulfill more demanding requirements, which can only be met by using electron-beam lithography. Replication techniques are more economical, since the high cost of the master can be distributed among a larger number of replicas. The lack of a suitable mold material for precision glass molding has so far prevented an industrial use. Glassy Carbon (GC) offers a high mechanical strength and high thermal strength. No anti-adhesion coatings are required in molding processes. This is clearly an advantage for high resolution, high aspect ratio microstructures, where a coating with a thickness between 10 nm and 200 nm would cause a noticeable rounding of the features. Electron-beam lithography was used to fabricate GC molds with highest precision and feature sizes from 250 nm to 2 μm. The master stamps were used for precision glass molding of a low Tg glass L-BAL42 from OHARA. The profile of the replicated glass is compared to the mold with the help of SEM images. This allows discussion of the max. aspect-ratio and min. feature size. To characterize optical performances, beamsplitting elements are fabricated and their characteristics were investigated, which are in excellent agreement to theory.

  11. Calibration of a High Resolution Airborne 3-D SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Grinder-Pedersen, Jan; Madsen, S.N.

    1997-01-01

    (EMI). In order to achieve a high geodetic fidelity when using such systems operationally, calibration procedures must be applied. Inaccurate navigation data and system parameters as well as system imperfections must be accounted for. This paper presents theoretical models describing the impact of key......The potential of across-track interferometric (XTI) synthetic aperture radar (SAR) for producing high resolution 3D imagery has been demonstrated by several airborne systems including EMISAR, the dual frequency, polarimetric, and interferometric SAR developed at the Dept. of Electromagnetic Systems...

  12. Coverage Options for a Low cost, High Resolution Optical Constellation

    OpenAIRE

    Price, M E; Levett, W.; Graham, K.

    2003-01-01

    This paper presents the range of coverage options available to TopSat like small satellites, both singly and in a small constellation. TopSat is a low-cost, high resolution and image quality, optical small satellite, due for launch in October 2004. In particular, the paper considers the use of tuned, repeat ground track orbits to improve coverage for selected ground targets, at the expense of global coverage. TopSat is designed to demonstrate the capabilities of small satellites for high valu...

  13. High resolution study of magnetic ordering at absolute zero.

    Science.gov (United States)

    Lee, M; Husmann, A; Rosenbaum, T F; Aeppli, G

    2004-05-07

    High resolution pressure measurements in the zero-temperature limit provide a unique opportunity to study the behavior of strongly interacting, itinerant electrons with coupled spin and charge degrees of freedom. Approaching the precision that has become the hallmark of experiments on classical critical phenomena, we characterize the quantum critical behavior of the model, elemental antiferromagnet chromium, lightly doped with vanadium. We resolve the sharp doubling of the Hall coefficient at the quantum critical point and trace the dominating effects of quantum fluctuations up to surprisingly high temperatures.

  14. High-resolution protein structure determination by serial femtosecond crystallography.

    Science.gov (United States)

    Boutet, Sébastien; Lomb, Lukas; Williams, Garth J; Barends, Thomas R M; Aquila, Andrew; Doak, R Bruce; Weierstall, Uwe; DePonte, Daniel P; Steinbrener, Jan; Shoeman, Robert L; Messerschmidt, Marc; Barty, Anton; White, Thomas A; Kassemeyer, Stephan; Kirian, Richard A; Seibert, M Marvin; Montanez, Paul A; Kenney, Chris; Herbst, Ryan; Hart, Philip; Pines, Jack; Haller, Gunther; Gruner, Sol M; Philipp, Hugh T; Tate, Mark W; Hromalik, Marianne; Koerner, Lucas J; van Bakel, Niels; Morse, John; Ghonsalves, Wilfred; Arnlund, David; Bogan, Michael J; Caleman, Carl; Fromme, Raimund; Hampton, Christina Y; Hunter, Mark S; Johansson, Linda C; Katona, Gergely; Kupitz, Christopher; Liang, Mengning; Martin, Andrew V; Nass, Karol; Redecke, Lars; Stellato, Francesco; Timneanu, Nicusor; Wang, Dingjie; Zatsepin, Nadia A; Schafer, Donald; Defever, James; Neutze, Richard; Fromme, Petra; Spence, John C H; Chapman, Henry N; Schlichting, Ilme

    2012-07-20

    Structure determination of proteins and other macromolecules has historically required the growth of high-quality crystals sufficiently large to diffract x-rays efficiently while withstanding radiation damage. We applied serial femtosecond crystallography (SFX) using an x-ray free-electron laser (XFEL) to obtain high-resolution structural information from microcrystals (less than 1 micrometer by 1 micrometer by 3 micrometers) of the well-characterized model protein lysozyme. The agreement with synchrotron data demonstrates the immediate relevance of SFX for analyzing the structure of the large group of difficult-to-crystallize molecules.

  15. High resolution upgrade of the ATF damping ring BPM system

    Energy Technology Data Exchange (ETDEWEB)

    Terunuma, N.; Urakawa, J.; /KEK, Tsukuba; Frisch, J.; May, J.; McCormick, D.; Nelson, J.; Seryi, A.; Smith, T.; Woodley, M.; /SLAC; Briegel, C.; Dysert, R.; /Fermilab

    2008-05-01

    A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility (ATF) damping ring has been accomplished in its first stage, carried out by a KEK/FNAL/SLAC collaboration under the umbrella of the global ILC R&D effort. The upgrade consists of a high resolution, high reproducibility read-out system, based on analog and digital downconversion techniques, digital signal processing, and also tests a new automatic gain error correction schema. The technical concept and realization, as well as preliminary results of beam studies are presented.

  16. Localized corrosion information using high resolution measurement devices

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2005-01-01

    to control the solution flow at the tip. Through addition of reference and counter electrodes, the pipette system becomes a microscopic electrochemical cell, which can then be used with high precision to determine the electrochemical characteristics of the microstructural region of interest. The capability...... of the technique could be further enhanced by adding new features such as high resolution video visualization systems, fretting/tribo-corroson attachments, and also by integrating it with stress corrosion testing, corrosion investigation of concrete for a few to name with. The corrosion group in MPT, Technical...

  17. High-resolution multimodal clinical multiphoton tomography of skin

    Science.gov (United States)

    König, Karsten

    2011-03-01

    This review focuses on multimodal multiphoton tomography based on near infrared femtosecond lasers. Clinical multiphoton tomographs for 3D high-resolution in vivo imaging have been placed into the market several years ago. The second generation of this Prism-Award winning High-Tech skin imaging tool (MPTflex) was introduced in 2010. The same year, the world's first clinical CARS studies have been performed with a hybrid multimodal multiphoton tomograph. In particular, non-fluorescent lipids and water as well as mitochondrial fluorescent NAD(P)H, fluorescent elastin, keratin, and melanin as well as SHG-active collagen has been imaged with submicron resolution in patients suffering from psoriasis. Further multimodal approaches include the combination of multiphoton tomographs with low-resolution wide-field systems such as ultrasound, optoacoustical, OCT, and dermoscopy systems. Multiphoton tomographs are currently employed in Australia, Japan, the US, and in several European countries for early diagnosis of skin cancer, optimization of treatment strategies, and cosmetic research including long-term testing of sunscreen nanoparticles as well as anti-aging products.

  18. Radiation length imaging with high-resolution telescopes

    Science.gov (United States)

    Stolzenberg, U.; Frey, A.; Schwenker, B.; Wieduwilt, P.; Marinas, C.; Lütticke, F.

    2017-02-01

    The construction of low mass vertex detectors with a high level of system integration is of great interest for next generation collider experiments. Radiation length images with a sufficient spatial resolution can be used to measure and disentangle complex radiation length X/X0 profiles and contribute to the understanding of vertex detector systems. Test beam experiments with multi GeV particle beams and high-resolution tracking telescopes provide an opportunity to obtain precise 2D images of the radiation length of thin planar objects. At the heart of the X/X0 imaging is a spatially resolved measurement of the scattering angles of particles traversing the object under study. The main challenges are the alignment of the reference telescope and the calibration of its angular resolution. In order to demonstrate the capabilities of X/X0 imaging, a test beam experiment has been conducted. The devices under test were two mechanical prototype modules of the Belle II vertex detector. A data sample of 100 million tracks at 4 GeV has been collected, which is sufficient to resolve complex material profiles on the 30 μm scale.

  19. Spatial-temperature high resolution map for early cancer diagnosis

    Science.gov (United States)

    Gavriloaia, Gheorghe V.; Hurduc, Anca; Ghimigean, Ana-Maria; Fumarel, Radu

    2009-02-01

    Heat is one of the most important parameters of living beings. Skin temperature is not the same on the entire body and so, a thermal signature can be got. Infrared map on serial imaging can constitute an early sign of an abnormality. Thermography detects changes in tissue that appear before and accompany many diseases including cancer. As this map has a better resolution an early cancer diagnosis can be done. The temperature of neoplasic tissue is different up to 1.5 °C than that of the healthy tissue as a result of the specific metabolic rate. The infrared camera images show very quickly the heat transferred by radiation. A lot of factors disturb the temperature conversion to pixel intensity. A sensitive temperature sensor with a 10 Mpixels video camera, showing its spatial position, and a computer fusion program were used for the map with high spatial-temperature resolution. A couple of minutes are necessary to get a high resolution map. The asymmetry and borders were the main parameters analyzed. The right cancer diagnosis was for about 78.4% of patients with thyroid cancer, and more than 89.6% from patients with breast cancer. In the near future, the medical prognosis will be improved by fractal analysis.

  20. Polystyrene negative resist for high-resolution electron beam lithography

    Directory of Open Access Journals (Sweden)

    Ma Siqi

    2011-01-01

    Full Text Available Abstract We studied the exposure behavior of low molecular weight polystyrene as a negative tone electron beam lithography (EBL resist, with the goal of finding the ultimate achievable resolution. It demonstrated fairly well-defined patterning of a 20-nm period line array and a 15-nm period dot array, which are the densest patterns ever achieved using organic EBL resists. Such dense patterns can be achieved both at 20 and 5 keV beam energies using different developers. In addition to its ultra-high resolution capability, polystyrene is a simple and low-cost resist with easy process control and practically unlimited shelf life. It is also considerably more resistant to dry etching than PMMA. With a low sensitivity, it would find applications where negative resist is desired and throughput is not a major concern.

  1. A new matching algorithm for high resolution mass spectra

    DEFF Research Database (Denmark)

    Hansen, Michael Edberg; Smedsgaard, Jørn

    2004-01-01

    We present a new matching algorithm designed to compare high-resolution spectra. Whereas existing methods are bound to compare fixed intervals of ion masses, the accurate mass spectrum (AMS) distance method presented here is independent of any alignment. Based on the Jeffreys-Matusitas (JM......) distance, a difference between observed peaks across pairs of spectra can be calculated, and used to find a unique correspondence between the peaks. The method takes into account that there may be differences in resolution of the spectra. The algorithm is used for indexing in a database containing 80...... accurate mass spectra from an analysis of extracts of 80 isolates representing the nine closely related species in the Penicillium series Viridicata. Using this algorithm we can obtain a retrieval performance of approximate to97-98% that is comparable with the best of the existing methods (e.g., the dot...

  2. Observations of solar scattering polarization at high spatial resolution

    CERN Document Server

    Snik, F; Ichimoto, K; Fischer, C E; Keller, C U; Lites, B W

    2010-01-01

    The weak, turbulent magnetic fields that supposedly permeate most of the solar photosphere are difficult to observe, because the Zeeman effect is virtually blind to them. The Hanle effect, acting on the scattering polarization in suitable lines, can in principle be used as a diagnostic for these fields. However, the prediction that the majority of the weak, turbulent field resides in intergranular lanes also poses significant challenges to scattering polarization observations because high spatial resolution is usually difficult to attain. We aim to measure the difference in scattering polarization between granules and intergranules. We present the respective center-to-limb variations, which may serve as input for future models. We perform full Stokes filter polarimetry at different solar limb positions with the CN band filter of the Hinode-SOT Broadband Filter Imager, which represents the first scattering polarization observations with sufficient spatial resolution to discern the granulation. Hinode-SOT offer...

  3. High resolution capacitance detection circuit for rotor micro-gyroscope

    Directory of Open Access Journals (Sweden)

    Ming-Yuan Ren

    2014-03-01

    Full Text Available Conventional methods for rotor position detection of micro-gyroscopes include common exciting electrodes (single frequency and common sensing electrodes (frequency multiplex, but they have encountered some problems. So we present a high resolution and low noise pick-off circuit for micro-gyroscopes which utilizes the time multiplex method. The detecting circuit adopts a continuous-time current sensing circuit for capacitance measurement, and its noise analysis of the charge amplifier is introduced. The equivalent output noise power spectral density of phase-sensitive demodulation is 120 nV/Hz1/2. Tests revealed that the whole circuitry has a relative capacitance resolution of 1 × 10−8.

  4. High resolution ultrasound and photoacoustic imaging of single cells.

    Science.gov (United States)

    Strohm, Eric M; Moore, Michael J; Kolios, Michael C

    2016-03-01

    High resolution ultrasound and photoacoustic images of stained neutrophils, lymphocytes and monocytes from a blood smear were acquired using a combined acoustic/photoacoustic microscope. Photoacoustic images were created using a pulsed 532 nm laser that was coupled to a single mode fiber to produce output wavelengths from 532 nm to 620 nm via stimulated Raman scattering. The excitation wavelength was selected using optical filters and focused onto the sample using a 20× objective. A 1000 MHz transducer was co-aligned with the laser spot and used for ultrasound and photoacoustic images, enabling micrometer resolution with both modalities. The different cell types could be easily identified due to variations in contrast within the acoustic and photoacoustic images. This technique provides a new way of probing leukocyte structure with potential applications towards detecting cellular abnormalities and diseased cells at the single cell level.

  5. High-resolution infrared observations of active galactic nuclei

    Science.gov (United States)

    Pott, Jörg-Uwe

    2012-07-01

    Interferometric resolution at IR wavelengths offers for the first time the possibility to zoom into the nuclei of galaxies beyond the circumnuclear stellar structures and spatially resolve gas and dust in the innermost regions (0.05-5pc), dominated by the central black hole. Ultimate goal is to reveal new aspects of AGN feeding, and interaction with its host galaxy. After first successes of resolving AGN with infrared interferometry (VLTI, Keck-IF), the second generation of high-resolution interferometric imagers behind 8m class telescopes is currently being built. I will summarize current aspects and successes of the field, and present our activities to provide extended capabilities for VLTI-Midi and -Matisse, LBT-Linc-Nirvana and Keck-Astra to study a larger sample of AGN in greater detail.

  6. High resolution ultrasound and photoacoustic imaging of single cells

    Directory of Open Access Journals (Sweden)

    Eric M. Strohm

    2016-03-01

    Full Text Available High resolution ultrasound and photoacoustic images of stained neutrophils, lymphocytes and monocytes from a blood smear were acquired using a combined acoustic/photoacoustic microscope. Photoacoustic images were created using a pulsed 532 nm laser that was coupled to a single mode fiber to produce output wavelengths from 532 nm to 620 nm via stimulated Raman scattering. The excitation wavelength was selected using optical filters and focused onto the sample using a 20× objective. A 1000 MHz transducer was co-aligned with the laser spot and used for ultrasound and photoacoustic images, enabling micrometer resolution with both modalities. The different cell types could be easily identified due to variations in contrast within the acoustic and photoacoustic images. This technique provides a new way of probing leukocyte structure with potential applications towards detecting cellular abnormalities and diseased cells at the single cell level.

  7. High-resolution proper motions in a sunspot penumbra

    CERN Document Server

    Márquez, I; Bonet, J A

    2006-01-01

    Local correlation tracking techniques are used to measure proper motions in a series of high angular resolution (~0.1 arcsec) penumbra images. If these motions trace true plasma motions, then we have detected converging flows that arrange the plasma in long narrow filaments co-spatial with dark penumbral filaments. Assuming that these flows are stationary, the vertical stratification of the atmosphere and the conservation of mass suggest downflows in the filaments of the order of 200 m/s. The association between downflows and dark features may be a sign of convection, as it happens with the non-magnetic granulation. Insufficient spatial resolution may explain why the estimated vertical velocities are not fast enough to supply the radiative losses of penumbrae.

  8. Microcalorimetry for High-Resolution X-Ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Stephen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-03

    Magnetic Microcalorimeters (MMCs) are gamma-ray detectors with an energy resolution 10x higher than high-purity germanium detectors. They can increase the accuracy of non-destructive analysis of nuclear materials, enable the detection of new isotopes (e.g. Pu-242 of U-236), and improve nuclear data in cases where Ge detectors are limited by line overlap. MMCs consist of a magnetic sensor operated at temperatures below 50 mK, and they infer gamma-ray energies from the change in magnetization due to the temperature increase after gamma-ray absorption. The goal of this project is to further increase the energy resolution and sensitivity of MMC gamma detectors.

  9. High-resolution NMR imaging of the hand

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, H.; Lucas, D.

    1986-12-01

    With high spatial resolution guaranteed, NMR imaging allows to simultaneously make visible the complex osseous, chondral, and ligamentous structures of the hand. The examinations reported on were made with a 1.0 Tesla Magnetom using a special surface coil so as to achieve cut heights of 3-4 mm and an in-plane resolution of 0.5 mm. In addition to normal test persons, 29 patients were examined who had pseudoarthrosis of the os naviculare, lunatomalacia, rheumatic arthritis, or bone and soft-tissue tumors. Comparison with X-ray radiography or bone scintiscans showed that NMR imaging is capable of demonstrating localisation and extension of bone marrow or bone joint abnormalities at an earlier stage.

  10. High-resolution friction force microscopy under electrochemical control

    Science.gov (United States)

    Labuda, Aleksander; Paul, William; Pietrobon, Brendan; Lennox, R. Bruce; Grütter, Peter H.; Bennewitz, Roland

    2010-08-01

    We report the design and development of a friction force microscope for high-resolution studies in electrochemical environments. The design choices are motivated by the experimental requirements of atomic-scale friction measurements in liquids. The noise of the system is analyzed based on a methodology for the quantification of all the noise sources. The quantitative contribution of each noise source is analyzed in a series of lateral force measurements. Normal force detection is demonstrated in a study of the solvation potential in a confined liquid, octamethylcyclotetrasiloxane. The limitations of the timing resolution of the instrument are discussed in the context of an atomic stick-slip measurement. The instrument is capable of studying the atomic friction contrast between a bare Au(111) surface and a copper monolayer deposited at underpotential conditions in perchloric acid.

  11. High-resolution multiphoton imaging of tumors in vivo.

    Science.gov (United States)

    Wyckoff, Jeffrey; Gligorijevic, Bojana; Entenberg, David; Segall, Jeffrey; Condeelis, John

    2011-10-01

    Analysis of the individual steps in metastasis is crucial if insights at the molecular level are to be linked to the cell biology of cancer. A technical hurdle to achieving the analysis of the individual steps of metastasis is the fact that, at the gross level, tumors are heterogeneous in both animal models and patients. Human primary tumors show extensive variation in all properties ranging from growth and morphology of the tumor through tumor-cell density in the blood and formation and growth of metastases. Methods capable of the direct visualization and analysis of tumor-cell behavior at single-cell resolution in vivo have become crucial in advancing the understanding of mechanisms of metastasis, the definition of microenvironment, and the markers related to both. This article discusses the use of high-resolution multiphoton imaging of tumors (specifically breast tumors in mice) in vivo.

  12. High spatial resolution soft-x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Meyer-Ilse, W.; Medecki, H.; Brown, J.T. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    A new soft x-ray microscope (XM-1) with high spatial resolution has been constructed by the Center for X-ray Optics. It uses bending magnet radiation from beamline 6.1 at the Advanced Light Source, and is used in a variety of projects and applications in the life and physical sciences. Most of these projects are ongoing. The instrument uses zone plate lenses and achieves a resolution of 43 nm, measured over 10% to 90% intensity with a knife edge test sample. X-ray microscopy permits the imaging of relatively thick samples, up to 10 {mu}m thick, in water. XM-1 has an easy to use interface, that utilizes visible light microscopy to precisely position and focus the specimen. The authors describe applications of this device in the biological sciences, as well as in studying industrial applications including structured polymer samples.

  13. Range ambiguity resolution for high PRF pulse-Doppler radar

    Science.gov (United States)

    Postema, G. B.

    The range ambiguity resolution for high 'PRF pulse-Doppler radars can be resolved using a simple algorithm based on residue arithmetic. The unambiguous range is found from R = T + R(a), where T is the output of a look-up table and R(a) is one of the measured ambiguous ranges. This formula is easily extended to multiple PRF ranging systems, where three or more measurements are required for the ambiguity resolution. Target obscuration in clutter reduces the visibility and leads, especially in dense target environments, to ghost ranges. It is shown that long range coverage requires a small resolved pulse length and PRFs as low as practical in the intended clutter and target environment. Special attention is given to the generation of sparsely populated look-up tables that reduce the ghosting problem. A practical example for an S-band surveillance radar is presented.

  14. High-Resolution Characterization of UMo Alloy Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Devaraj, Arun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kovarik, Libor [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jana, Saumyadeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Manandhar, Sandeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arey, Bruce W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-11-30

    This report highlights the capabilities and procedure for high-resolution characterization of UMo fuels in PNNL. Uranium-molybdenum (UMo) fuel processing steps, from casting to forming final fuel, directly affect the microstructure of the fuel, which in turn dictates the in-reactor performance of the fuel under irradiation. In order to understand the influence of processing on UMo microstructure, microstructure characterization techniques are necessary. Higher-resolution characterization techniques like transmission electron microscopy (TEM) and atom probe tomography (APT) are needed to interrogate the details of the microstructure. The findings from TEM and APT are also directly beneficial for developing predictive multiscale modeling tools that can predict the microstructure as a function of process parameters. This report provides background on focused-ion-beam–based TEM and APT sample preparation, TEM and APT analysis procedures, and the unique information achievable through such advanced characterization capabilities for UMo fuels, from a fuel fabrication capability viewpoint.

  15. High-Resolution, Wide-Field-of-View Scanning Telescope

    Science.gov (United States)

    Sepulveda, Cesar; Wilson, Robert; Seshadri, Suresh

    2007-01-01

    A proposed telescope would afford high resolution over a narrow field of view (<0.10 ) while scanning over a total field of view nominally 16 wide without need to slew the entire massive telescope structure. The telescope design enables resolution of a 1-m-wide object in a 50- km-wide area of the surface of the Earth as part of a 200-km-wide area field of view monitored from an orbit at an altitude of 700 km. The conceptual design of this telescope could also be adapted to other applications both terrestrial and extraterrestrial in which there are requirements for telescopes that afford both wide- and narrow-field capabilities. In the proposed telescope, the scanning would be effected according to a principle similar to that of the Arecibo radio telescope, in which the primary mirror is stationary with respect to the ground and a receiver is moved across the focal surface of the primary mirror. The proposed telescope would comprise (1) a large spherical primary mirror that would afford high resolution over a narrow field of view and (2) a small displaceable optical relay segment that would be pivoted about the center of an aperture stop to effect the required scanning (see figure). Taken together, both comprise a scanning narrow-angle telescope that does not require slewing the telescope structure. In normal operation, the massive telescope structure would stare at a fixed location on the ground. The inner moveable relay optic would be pivoted to scan the narrower field of view over the wider one, making it possible to retain a fixed telescope orientation, while obtaining high-resolution images over multiple target areas during an interval of 3 to 4 minutes in the intended orbit. The pivoting relay segment of the narrow-angle telescope would include refractive and reflective optical elements, including two aspherical mirrors, to counteract the spherical aberration of the primary mirror. Overall, the combination of the primary mirror and the smaller relay optic

  16. High Resolution Infrared Spectroscopy of Allene -D4.

    Science.gov (United States)

    Rousan, Khetam Ibrahim Khasawinah

    Two parallel bands of allene-d(,4), (nu)(,6) (occurring at 1920.2289 cm('-1)) and (nu)(,5) (occurring at 2228.4133 cm('-1)), and the perpendicular band, (nu)(,8) (occurring at 2321.2484 cm('-1)), were recorded by using two spectrometers under high resolution. The combination band, (nu)(,2) + (nu)(,7), was measured also; the band origin is located at 2276.0053 cm('-1), rather distant from the previously reported one at 2267.0 cm('-1). Initially, by using the 4.5 m grating spectrometer, deconvolution of the spectra achieved a resolution of (TURN)0.007 cm('-1). Although the resolution was high, a detailed analysis of the K structure could not be obtained. Other measurements were carried out by using a BOMEM Fourier transform spectrometer. Deconvolution of the spectra achieved a resolution of (TURN)0.002 cm(' -1). This made it possible to resolve and analyze these bands in detail. Successful ground state and upper state analyses were completed from this data. Combining all the three bands together, a ground state analysis has resulted in better values of. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). than the previously published works on the same molecule by others. A set of accurate spectroscopic constants was obtained for each band. The spectrum of the (nu)(,8) band was analyzed in detail, including the perturbations. The perturbed states for (nu)(,8) were assigned as 2(nu)(,9) + (nu)(,10), (nu)(,2) + (nu)(,9) + (nu)(,11) and 2(nu)(,3) + (nu)(,4), and the spectroscopic constants for those perturbed states were calculated.

  17. The Effect of Magnetic Field on Positron Range and Spatial Resolution in an Integrated Whole-Body Time-Of-Flight PET/MRI System.

    Science.gov (United States)

    Huang, Shih-Ying; Savic, Dragana; Yang, Jaewon; Shrestha, Uttam; Seo, Youngho

    2014-11-01

    Simultaneous imaging systems combining positron emission tomography (PET) and magnetic resonance imaging (MRI) have been actively investigated. A PET/MR imaging system (GE Healthcare) comprised of a time-of-flight (TOF) PET system utilizing silicon photomultipliers (SiPMs) and 3-tesla (3T) MRI was recently installed at our institution. The small-ring (60 cm diameter) TOF PET subsystem of this PET/MRI system can generate images with higher spatial resolution compared with conventional PET systems. We have examined theoretically and experimentally the effect of uniform magnetic fields on the spatial resolution for high-energy positron emitters. Positron emitters including (18)F, (124)I, and (68)Ga were simulated in water using the Geant4 Monte Carlo toolkit in the presence of a uniform magnetic field (0, 3, and 7 Tesla). The positron annihilation position was tracked to determine the 3D spatial distribution of the 511-keV gammy ray emission. The full-width at tenth maximum (FWTM) of the positron point spread function (PSF) was determined. Experimentally, (18)F and (68)Ga line source phantoms in air and water were imaged with an investigational PET/MRI system and a PET/CT system to investigate the effect of magnetic field on the spatial resolution of PET. The full-width half maximum (FWHM) of the line spread function (LSF) from the line source was determined as the system spatial resolution. Simulations and experimental results show that the in-plane spatial resolution was slightly improved at field strength as low as 3 Tesla, especially when resolving signal from high-energy positron emitters in the air-tissue boundary.

  18. High-resolution absorption measurements of NH3 at high temperatures: 500–2100cm−1

    DEFF Research Database (Denmark)

    Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan

    2015-01-01

    High-resolution absorption spectra of NH3 in the region 500–2100 cm -1 at temperatures up to1027 1C and approximately atmospheric pressure (1013±20 mbar) are measured. NH3 concentrations of 1000 ppm,0.5% and 1% in volume fraction were used in the measurements. Spectra are recorded in high...... temperature gas flow cells using a FourierTransform Infrared (FTIR) spectrometer at a nominal resolution of 0.09cm-1. Measurements at 22.7 °C are compared to high-resolution cross sections available from thePacific Northwest National Laboratory (PNNL). The higher temperature spectra are analysed by comparison...

  19. On high-resolution manoeuvres control via trajectory optimization

    Indian Academy of Sciences (India)

    A H MAZINAN; M SHAHI

    2017-02-01

    This research is on a realization of control approach in line with the trajectory optimization for the purpose of dealing with overactuated spacecraft in the process of the high-resolution manoeuvres. The idea behind the research is to realize closed control loops to cope with the rotational angles and the corresponding angular rates,synchronously, to handle the spacecraft manoeuvres. It is to be noted that the traditional techniques may not have sufficient merit to deal with such a complicated process, suitably. The proposed trajectory optimization is designed to provide the three-axis referenced commands, in finite burn, for transferring the aforementioned overactuated spacecraft from the initial orbit to its final outcomes in the orbital transfer process. The outcomes are realized through the variations of the orbital parameters, including the inclination, the eccentricity, the angular momentum, the semi-major axis and so on, in the high-resolution manoeuvres. It aims to get the system under control to guarantee the performance of the three-dimensional rotational angles tracking to be desirable, instantly. The contribution of the research is to make the high-thrust optimization trajectory,which is organized in association with the new configuration of the three-axis attitude control approach, to be applicable to manage the present overactuated spacecraft in the procedure of high-resolution orbital transfer process. The investigated outcomes of the research are efficient and competitive along with the potential materials through a series of experiments, as long as the desirable tracking performance in the three-dimensional space manoeuvres is apparently guaranteed.

  20. Full-sky, High-resolution Maps of Interstellar Dust

    Science.gov (United States)

    Meisner, Aaron Michael

    We present full-sky, high-resolution maps of interstellar dust based on data from the Wide-field Infrared Survey Explorer (WISE) and Planck missions. We describe our custom processing of the entire WISE 12 micron All-Sky imaging data set, and present the resulting 15 arcsecond resolution, full-sky map of diffuse Galactic dust emission, free of compact sources and other contaminating artifacts. Our derived 12 micron dust map offers angular resolution far superior to that of all other existing full-sky, infrared dust emission maps, revealing a wealth of small-scale filamentary structure. We also apply the Finkbeiner et al. (1999) two-component thermal dust emission model to the Planck HFI maps. We derive full-sky 6.1 arcminute resolution maps of dust optical depth and temperature by fitting this two-component model to Planck 217-857 GHz along with DIRBE/IRAS 100 micron data. In doing so, we obtain the first ever full-sky 100-3000 GHz Planck-based thermal dust emission model, as well as a dust temperature correction with ~10 times enhanced angular resolution relative to DIRBE-based temperature maps. Analyzing the joint Planck/DIRBE dust spectrum, we show that two-component models provide a better fit to the 100-3000 GHz emission than do single-MBB models, though by a lesser margin than found by Finkbeiner et al. (1999) based on FIRAS and DIRBE. We find that, in diffuse sky regions, our two-component 100-217 GHz predictions are on average accurate to within 2.2%, while extrapolating the Planck Collaboration (2013) single-MBB model systematically underpredicts emission by 18.8% at 100 GHz, 12.6% at 143 GHz and 7.9% at 217 GHz. We calibrate our two-component optical depth to reddening, and compare with reddening estimates based on stellar spectra. We find the dominant systematic problems in our temperature/reddening maps to be zodiacal light on large angular scales and the cosmic infrared background anisotropy on small angular scales. Future work will focus on combining