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Sample records for 2d multi-slice mri

  1. Predictive Modelling of Cardiac 2D Multi-Slice MRI with Simultaneous Resolution of Cardiac and Respiratory Motion

    Pedersen, Henrik; Ólafsdóttir, Hildur; Darkner, Sune; Lyksborg, Mark; Larsen, Rasmus

    2009-01-01

    This paper introduces a novel approach to modelling of volumetric cardiac magnetic resonance imaging (MRI) with simultaneous resolution of cardiac and respiratory motion. The major challenge is that the inherent slow nature of MRI prevents obtaining real-time volumetric images of the heart with sufficient spatial and temporal resolution. To overcome this problem our method predicts pixel intensities in multiple 2D slices, acquired with high spatial and temporal resolution, and subsequently as...

  2. Predictive Modelling of Cardiac 2D Multi-Slice MRI with Simultaneous Resolution of Cardiac and Respiratory Motion

    Pedersen, Henrik; Ólafsdóttir, Hildur; Darkner, Sune;

    2009-01-01

    This paper introduces a novel approach to modelling of volumetric cardiac magnetic resonance imaging (MRI) with simultaneous resolution of cardiac and respiratory motion. The major challenge is that the inherent slow nature of MRI prevents obtaining real-time volumetric images of the heart with...... respiratory bellow and a vectorcardiogram, and utilizes a combination of deformation modelling and pixel intensity modelling. We demonstrate that this approach reliably models volumetric cardiac MRI for any combination of cardiac and respiratory phase....

  3. Ultrafast multi-slice spatiotemporally encoded MRI with slice-selective dimension segmented.

    Zhang, Ting; Chen, Lin; Huang, Jianpan; Li, Jing; Cai, Shuhui; Cai, Congbo; Chen, Zhong

    2016-08-01

    As a recently emerging method, spatiotemporally encoded (SPEN) magnetic resonance imaging (MRI) has a high robustness to field inhomogeneity and chemical shift effect. It has been broadened from single-slice scanning to multi-slice scanning. In this paper, a novel multi-slice SPEN MRI method was proposed. In this method, the slice-selective dimension was segmented to lower the specific absorption rate (SAR) and improve the image quality. This segmented method, dubbed SeSPEN method, was theoretically analyzed and demonstrated with phantom, lemon and in vivo rat brain experiments. The experimental results were compared with the results obtained from the spin-echo EPI, spin-echo SPEN method and multi-slice global SPEN method proposed by Frydman and coauthors (abbr. GlSPEN method). All the SPEN images were super-resolved reconstructed using deconvolution method. The results indicate that the SeSPEN method retains the advantage of SPEN MRI with respect to resistance to field inhomogeneity and can provide better signal-to-noise ratio than multi-slice GlSPEN MRI technique. The SeSPEN method has comparable SAR to the GlSPEN method while the T1 signal attenuation effect is alleviated. The proposed method will facilitate the multi-slice SPEN MRI to scan more slices within one scan with better image quality. PMID:27301072

  4. Ultrafast multi-slice spatiotemporally encoded MRI with slice-selective dimension segmented

    Zhang, Ting; Chen, Lin; Huang, Jianpan; Li, Jing; Cai, Shuhui; Cai, Congbo; Chen, Zhong

    2016-08-01

    As a recently emerging method, spatiotemporally encoded (SPEN) magnetic resonance imaging (MRI) has a high robustness to field inhomogeneity and chemical shift effect. It has been broadened from single-slice scanning to multi-slice scanning. In this paper, a novel multi-slice SPEN MRI method was proposed. In this method, the slice-selective dimension was segmented to lower the specific absorption rate (SAR) and improve the image quality. This segmented method, dubbed SeSPEN method, was theoretically analyzed and demonstrated with phantom, lemon and in vivo rat brain experiments. The experimental results were compared with the results obtained from the spin-echo EPI, spin-echo SPEN method and multi-slice global SPEN method proposed by Frydman and coauthors (abbr. GlSPEN method). All the SPEN images were super-resolved reconstructed using deconvolution method. The results indicate that the SeSPEN method retains the advantage of SPEN MRI with respect to resistance to field inhomogeneity and can provide better signal-to-noise ratio than multi-slice GlSPEN MRI technique. The SeSPEN method has comparable SAR to the GlSPEN method while the T1 signal attenuation effect is alleviated. The proposed method will facilitate the multi-slice SPEN MRI to scan more slices within one scan with better image quality.

  5. Unsupervised motion-compensation of multi-slice cardiac perfusion MRI

    Stegmann, M.B.; Ólafsdóttir, H; Larsson, H.B.W.

    2005-01-01

    This paper presents a novel method for registration of single and multi-slice cardiac perfusion MRI. Utilising off-line computer intensive analyses of variance and clustering in an annotated training set, the presented method is capable of providing registration without any manual interaction in...... holds great promise for the automation of cardiac perfusion investigations, due to its accuracy, robustness and generalisation ability...

  6. Unsupervised motion-compensation of multi-slice cardiac perfusion MRI

    Stegmann, Mikkel Bille; Ólafsdóttir, Hildur; Larsson, Henrik B. W.

    2005-01-01

    This paper presents a novel method for registration of single and multi-slice cardiac perfusion MRI. Utilising computer intensive analyses of variance and clustering in an annotated training set off-line, the presented method is capable of providing registration without any manual interaction in...... holds great promise for the automation of cardiac perfusion investigations, due to its accuracy, robustness and generalisation ability....

  7. Value of MRI with sliding multi-slice technique for staging ovarian carcinoma

    Objective: To analyze the technical characteristics of sliding multi-slice magnetic resonance imaging (SMS-MRI), and to evaluate the value of staging ovarian carcinoma by SMS-MRI. Methods: Pre-operative SMS-MRI of chest, abdomen and pelvis was performed on 15 patients with ovarian carcinoma. Sequences included TSE T2WI, SMS TIRM and fat-suppressed contrast-enhanced SMS FLASH. The SMS-MRI was analyzed and staged according to FIGO's classification by two radiologists. The location of tumor, local invasion of uterus and fallopian tube or other pelvic tissues, peritoneum metastasis, lymph node metastasis and distal metastasis were recorded. The results were compared with operative and pathological findings. Results: The pathological diagnosis was serous cystadenocarcinoma (9), mucinous cystadenocarcinoma (2), endometrioid carcinoma (2), clear cell carcinoma (1) and granular cell carcinoma (1) at stage II (2), stage III (10) and stage IV (3). The accuracy of SMS-MRI staging was 100% (15/15). The tumor location, involvement of uterus and fallopian tubes as well as distant metastasis were accurately demonstrated by SMS-MRI. Conclusion: SMS-MRI can be a faster one-stop examination with good image quality. SMS-MRI is an alternative imaging method of staging ovarian carcinoma. (authors)

  8. Fast high resolution reconstruction in multi-slice and multi-view cMRI

    Velasco Toledo, Nelson; Romero Castro, Eduardo

    2015-01-01

    Cardiac magnetic resonance imaging (cMRI) is an useful tool in diagnosis, prognosis and research since it functionally tracks the heart structure. Although useful, this imaging technique is limited in spatial resolution because heart is a constant moving organ, also there are other non controled conditions such as patient movements and volumetric changes during apnea periods when data is acquired, those conditions limit the time to capture high quality information. This paper presents a very fast and simple strategy to reconstruct high resolution 3D images from a set of low resolution series of 2D images. The strategy is based on an information reallocation algorithm which uses the DICOM header to relocate voxel intensities in a regular grid. An interpolation method is applied to fill empty places with estimated data, the interpolation resamples the low resolution information to estimate the missing information. As a final step a gaussian filter that denoises the final result. A reconstructed image evaluation is performed using as a reference a super-resolution reconstructed image. The evaluation reveals that the method maintains the general heart structure with a small loss in detailed information (edge sharpening and blurring), some artifacts related with input information quality are detected. The proposed method requires low time and computational resources.

  9. Juxta-adrenal schwannoma: Dynamic multi-slice CT and MRI findings

    Background: We retrospectively analyzed the MSCT and MRI findings of three cases of juxta-adrenal schwannoma and reviewed literature. Methods and results: Three patients were male, and showed no signs for endocrine activity. The three cases of juxta-adrenal schwannoma were all well-circumscribed, oval masses with cystic components, and one case with hemorrhage. Hypointense signal capsules were observed on T2-weighted images in two cases, and the capsule in one case showed rim enhancement. The tumors displayed mild enhancement in the arterial phase and progressive enhancement during the portal venous phase and equilibrium phase. Computed tomography angiography clearly showed the tumor feeding vessels arising from the abdominal aorta. Conclusions: MSCT and MRI are valuable imaging modalities for diagnosis of juxta-adrenal schwannoma.

  10. Multi-slice CT and MRI findings of the Listranc's ligament injuries

    Objective: To explore the multislice CT and MRI features of the Lisfranc's ligament injuries. Methods: In 23 cases of the tarsometatarsal joins injuries, 16 are men and 7 are women. The average age is 37 years(range 17-67 years). Ten cases are induced by the direct force and 13 cases are caused by the indirect force. All of the 23 cases were examined by the Siemens 64-slice CT scan, and then reformatted the tarsometatarsal joins with the MPR, CPR, SSD and VR. Ten of 23 cases were examined by oblique axial, sagittal and coronal view of the Siemens 1.5 T MRI. Results: On CT, the distance between the second metatarsus base and the medial cuneiform showed increase in 14 cases and the distance between the base of the second metatarsus and the first metatarsus was over 2 mm. In addition, the inside base of the second metatarsus and the lateral edge of the first cuneiform bone revealed fractures in 5 cases, respectively. The above CT characteristics may suggest the injuries of Lisfranc's ligament. Ten of the 14 cases were examined by MRI. The Lisfranc ligament was found to have injuries in these cases. The injuries were divided into 3 types: type I (Lisfranc ligament breaks) was 5 cases; type II (Lisfranc ligament shape is complete, but accompanied with avulsion fracture of the second metatarsal bone basis interior margin of attachment point of Lisfranc ligament) was 4 cases; and type III (Lisfranc ligament shape is complete, but accompanied with avulsion fracture of exterior margin of the inside cuneiform of attachment point of Lisfranc ligament) was 1 case. Conclusion: CT can demonstrate local soft tissue swelling, suggesting the Lisfranc ligament damage, and demonstrate clearly avulsion fracture of attachment point of Lisfranc ligament, but MRI can appraise accurately the Lisfranc ligament injuries. (authors)

  11. Recurrent Fully Convolutional Neural Networks for Multi-slice MRI Cardiac Segmentation

    Poudel, Rudra P K; Lamata, Pablo; Montana, Giovanni

    2016-01-01

    In cardiac magnetic resonance imaging, fully-automatic segmentation of the heart enables precise structural and functional measurements to be taken, e.g. from short-axis MR images of the left-ventricle. In this work we propose a recurrent fully-convolutional network (RFCN) that learns image representations from the full stack of 2D slices and has the ability to leverage inter-slice spatial dependences through internal memory units. RFCN combines anatomical detection and segmentation into a si...

  12. Functional Study of the Heart using MRI and Multi-slice CT (MSCT

    "Sh. Akhlaghpour

    2005-08-01

    Full Text Available Introduction & Background: By using newer imaging techniques (MRI and MSCT, it is possible to perform functional studies of the heart including, wall mo-tion, chamber volume evaluation, and myocardial mass and wall thickness. While MRI had recently been introduced as the gold standard method for the morphological and functional studies of the heart, recent advances in the number of detectors, rotation time, and reconstruction protocols made Multislice CT (MSCT another new application for functional studies of the heart too. Ordinary raw data for coro-nary CT angiography is sufficient for these functional studies. Apart from the point that which technique is to be used to get a standard and reproducible meas-urement, a proper imaging strategy is necessary. To use MSCT, various softwares are available for these studies. By the use of these two modalities, valvular evaluations are also possible as addressed in many recent publications. In this article the strategy for functional study of the heart is presented and some case studies are also discussed.

  13. 3D visualisation of the middle ear and adjacent structures using reconstructed multi-slice CT datasets, correlating 3D images and virtual endoscopy to the 2D cross-sectional images

    The 3D imaging of the middle ear facilitates better understanding of the patient's anatomy. Cross-sectional slices, however, often allow a more accurate evaluation of anatomical structures, as some detail may be lost through post-processing. In order to demonstrate the advantages of combining both approaches, we performed computed tomography (CT) imaging in two normal and 15 different pathological cases, and the 3D models were correlated to the cross-sectional CT slices. Reconstructed CT datasets were acquired by multi-slice CT. Post-processing was performed using the in-house software ''3D Slicer'', applying thresholding and manual segmentation. 3D models of the individual anatomical structures were generated and displayed in different colours. The display of relevant anatomical and pathological structures was evaluated in the greyscale 2D slices, 3D images, and the 2D slices showing the segmented 2D anatomy in different colours for each structure. Correlating 2D slices to the 3D models and virtual endoscopy helps to combine the advantages of each method. As generating 3D models can be extremely time-consuming, this approach can be a clinically applicable way of gaining a 3D understanding of the patient's anatomy by using models as a reference. Furthermore, it can help radiologists and otolaryngologists evaluating the 2D slices by adding the correct 3D information that would otherwise have to be mentally integrated. The method can be applied to radiological diagnosis, surgical planning, and especially, to teaching. (orig.)

  14. MRI in soils: determination of water concent changes due to root water uptake by means of a multi-slice-multi-echo sequence (MSME)

    Pohlmeier, A.; Vergeldt, F.; Gerkema, E.; As, van H.; Dusschoten, van D.; Vereecken, H.

    2010-01-01

    Root water uptake by ricinus communis (castor bean) in fine sand was investigated using MRI with multiecho sampling. Before starting the experiments the plants germinated and grew for 3 weeks in a cylindrical container with a diameter of 9 cm. Immediately before the MRI experiments started, the cont

  15. Multi-slice CT (MSCT) in cardiac function imaging: threshold-value-supported 3D volume reconstructions to determine the left ventricular ejection fraction in comparison to MRI

    Purpose: To assess MSCT of the heart to determining left ventricular ejection fraction (EF) based on threshold-value-supported 3D volume reconstructions compared to MRI. Methods: Cardiac MSCT was performed in 7 patients. Images were reconstructed during end-systolic and end-diastolic phases of the cardiac cycle and transformed to 3D volumes to determine end-systolic (ESV) and end-diastolic volume (EDV) by using different lower threshold values: besides fixed lower threshold values, identical for each image sequence, individual lower threshold values dependent on contrast enhancement of the left ventricle were applied. The latter represent the mean value calculated by combining the average CT-density of the myocardium and the contrast-enhanced blood in the left ventricle. The EF derived from ESV and EDV. Results: The best correlation with MR imaging was obtained for ESV and EDV by using the individual lower threshold values for the respective sequence. The correlation coefficient for ESV was 0.95 and for EDV it was 0.93. On average, the ESV was overestimated by 3.72 ml, while the ESD was underestimated by 2.85 ml. The respective standard deviation for the ESV was 14,87 ml, for the EDV it was 26.83 ml. On average, the EF was underestimated by 3.57% with a standard deviation of 9.43% and a correlation coefficient of 0.83 in comparison to MRI. Conclusion: The threshold-value-supported 3D volume reconstruction of the left ventricle represents a good method to determine the left ventricular function parameters. Due to the differences in the contrast enhancement, the use of an individual lower threshold value for every image sequence is of particular importance. (orig.)

  16. High-resolution multi-slice PET

    This report evaluates the progress to test the feasibility and to initiate the design of a high resolution multi-slice PET system. The following specific areas were evaluated: detector development and testing; electronics configuration and design; mechanical design; and system simulation. The design and construction of a multiple-slice, high-resolution positron tomograph will provide substantial improvements in the accuracy and reproducibility of measurements of the distribution of activity concentrations in the brain. The range of functional brain research and our understanding of local brain function will be greatly extended when the development of this instrumentation is completed

  17. Enhancement of the low resolution image quality using randomly sampled data for multi-slice MR imaging

    Pang, Yong; Yu, Baiying; Zhang, Xiaoliang

    2014-01-01

    Low resolution images are often acquired in in vivo MR applications involving in large field-of-view (FOV) and high speed imaging, such as, whole-body MRI screening and functional MRI applications. In this work, we investigate a multi-slice imaging strategy for acquiring low resolution images by using compressed sensing (CS) MRI to enhance the image quality without increasing the acquisition time. In this strategy, low resolution images of all the slices are acquired using multiple-slice imag...

  18. Comparison of 3D MRI with high sampling efficiency and 2D multiplanar MRI for contouring in cervix cancer brachytherapy

    MRI sequences with short scanning times may improve accessibility of image guided adaptive brachytherapy (IGABT) of cervix cancer. We assessed the value of 3D MRI for contouring by comparing it to 2D multi-planar MRI. In 14 patients, 2D and 3D pelvic MRI were obtained at IGABT. High risk clinical target volume (HR CTV) was delineated by 2 experienced radiation oncologists, using the conventional (2D MRI-based) and test (3D MRI-based) approach. The value of 3D MRI for contouring was evaluated by using the inter-approach and inter-observer analysis of volumetric and topographic contouring uncertainties. To assess the magnitude of deviation from the conventional approach when using the test approach, the inter-approach analysis of contouring uncertainties was carried out for both observers. In addition, to assess reliability of 3D MRI for contouring, the impact of contouring approach on the magnitude of inter-observer delineation uncertainties was analysed. No approach- or observer - specific differences in HR CTV sizes, volume overlap, or distances between contours were identified. When averaged over all delineated slices, the distances between contours in the inter-approach analysis were 2.6 (Standard deviation (SD) 0.4) mm and 2.8 (0.7) mm for observers 1 and 2, respectively. The magnitude of topographic and volumetric inter-observer contouring uncertainties, as obtained on the conventional approach, was maintained on the test approach. This variation was comparable to the inter-approach uncertainties with distances between contours of 3.1 (SD 0.8) and 3.0 (SD 0.7) mm on conventional and test approach, respectively. Variation was most pronounced at caudal HR CTV levels in both approaches and observers. 3D MRI could potentially replace multiplanar 2D MRI in cervix cancer IGABT, shortening the overall MRI scanning time and facilitating the contouring process, thus making this treatment method more widely employed

  19. Neurovascular coupling to D2/D3 dopamine receptor occupancy using simultaneous PET/functional MRI

    Sander, Christin Y; Hooker, Jacob M; Catana, Ciprian;

    2013-01-01

    This study employed simultaneous neuroimaging with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to demonstrate the relationship between changes in receptor occupancy measured by PET and changes in brain activity inferred by fMRI. By administering the D2/D3...... responses and receptor occupancies. The distinct CBV magnitudes between putamen and caudate at matched occupancies approximately matched literature differences in basal dopamine levels, suggesting that the relative fMRI measurements reflect basal D2/D3 dopamine receptor occupancy. These results can provide...

  20. Comparison of the Value of Multi-slice Spiral CT and MRI in the Diagnosis of Biliary Obstructive Diseases%多排螺旋CT、MRI在诊断胆道梗阻性病变中价值比较

    孙永峰

    2015-01-01

    目的:探讨多排螺旋CT及MRI在胆道梗阻性病变患者中的临床诊断价值差异。方法选取112例经手术病理检查确诊的胆道梗阻性病变患者为研究对象,均行多排螺旋CT及MRI检查,详细记录检查结果。以手术病理检查结果为“金标准”,评估多排螺旋CT及MRI在胆道肠梗阻性疾病中的定位、定性诊断符合率差异。结果①多排螺旋CT病灶定位符合率为95.5%,同MRI的97.3%对比无统计学意义(P>0.05);②MRI定性诊断胆道梗阻性疾病的准确率为91.1%,显著高于多螺旋CT的77.7%,差异具有统计学意义(P0.05). ②The accuracy rate of MRI in qualitative diagnosis ofbiliary obstructive diseases was 91.1% which was significantly higher than 77.7% ofmulti-slice spiral CT, and the difference was statistically significant (P<0.05).Conclusion To apply multiple-sequence MRI in diagnosis of patients with suspected biliary obstructiv diseases, the accuracy rate of location and qualitative diagnosis is relatively higher, which is beneficial to improve the accuracy and effectiveness of early diagnosis and has positive on saving consultation hours and carrying out the follow-uptreatmentsmoothly. It is worthy of clinical promotion.

  1. Image Reconstruction from 2D stack of MRI/CT to 3D using Shapelets

    Arathi T; Latha Parameswaran

    2014-01-01

    Image reconstruction is an active research field, due to the increasing need for geometric 3D models in movie industry, games, virtual environments and in medical fields. 3D image reconstruction aims to arrive at the 3D model of an object, from its 2D images taken at different viewing angles. Medical images are multimodal, which includes MRI, CT scan image, PET and SPECT images. Of these, MRI and CT scan images of an organ when taken, is available as a stack of 2D images, taken at different a...

  2. Image Reconstruction from 2D stack of MRI/CT to 3D using Shapelets

    Arathi T

    2014-12-01

    Full Text Available Image reconstruction is an active research field, due to the increasing need for geometric 3D models in movie industry, games, virtual environments and in medical fields. 3D image reconstruction aims to arrive at the 3D model of an object, from its 2D images taken at different viewing angles. Medical images are multimodal, which includes MRI, CT scan image, PET and SPECT images. Of these, MRI and CT scan images of an organ when taken, is available as a stack of 2D images, taken at different angles. This 2D stack of images is used to get a 3D view of the organ of interest, to aid doctors in easier diagnosis. Existing 3D reconstruction techniques are voxel based techniques, which tries to reconstruct the 3D view based on the intensity value stored at each voxel location. These techniques don’t make use of the shape/depth information available in the 2D image stack. In this work, a 3D reconstruction technique for MRI/CT 2D image stack, based on Shapelets has been proposed. Here, the shape/depth information available in each 2D image in the image stack is manipulated to get a 3D reconstruction, which gives a more accurate 3D view of the organ of interest. Experimental results exhibit the efficiency of this proposed technique.

  3. Dynamic bowtie filter for cone-beam/multi-slice CT.

    Fenglin Liu

    Full Text Available A pre-patient attenuator ("bowtie filter" or "bowtie" is used to modulate an incoming x-ray beam as a function of the angle of the x-ray with respect to a patient to balance the photon flux on a detector array. While the current dynamic bowtie design is focused on fan-beam geometry, in this study we propose a methodology for dynamic bowtie design in multi-slice/cone-beam geometry. The proposed 3D dynamic bowtie is an extension of the 2D prior art. The 3D bowtie consists of a highly attenuating bowtie (HB filled in with heavy liquid and a weakly attenuating bowtie (WB immersed in the liquid of the HB. The HB targets a balanced flux distribution on a detector array when no object is in the field of view (FOV. The WB compensates for an object in the FOV, and hence is a scaled-down version of the object. The WB is rotated and translated in synchrony with the source rotation and patient translation so that the overall flux balance is maintained on the detector array. First, the mathematical models of different scanning modes are established for an elliptical water phantom. Then, a numerical simulation study is performed to compare the performance of the scanning modes in the cases of the water phantom and a patient cross-section without any bowtie and with a dynamic bowtie. The dynamic bowtie can equalize the numbers of detected photons in the case of the water phantom. In practical cases, the dynamic bowtie can effectively reduce the dynamic range of detected signals inside the FOV. Furthermore, the WB can be individualized using a 3D printing technique as the gold standard. We have extended the dynamic bowtie concept from 2D to 3D by using highly attenuating liquid and moving a scale-reduced negative copy of an object being scanned. Our methodology can be applied to reduce radiation dose and facilitate photon-counting detection.

  4. The value of multi-slice computed tomography for early diagnosis of focal cerebral ischemia

    The aim of this survey is the characterization of the present value of multi-slice computed tomography (MSCT) for the assessment of hyperacute cerebral ischemia based on our experience and a review of the literature. MSCT is compared with single-slice CT (SSCT) as to the diagnostic value of standard cranial CT, CT angiography (CTA) and perfusion CT. CTA obtained with MSCT surpasses CTA obtained with SSCT. For perfusion CT, the value added by MSCT is small. With regard to standard cranial CT, MSCT and SSCT are considered equivalent. CTA and perfusion CT should be used in patients with acute stroke if the indication for thrombolysis is entertained but diffusion and perfusion weighted MRI cannot be carried out. This applies to both SSCT and MSCT. If advanced MRI and advanced CT are available, MRI continues to be the preferred imaging modality. (orig.)

  5. Real-time 2D spatially selective MRI experiments: Comparative analysis of optimal control design methods

    Maximov, Ivan I.; Vinding, Mads S.; Tse, Desmond H. Y.; Nielsen, Niels Chr.; Shah, N. Jon

    2015-05-01

    There is an increasing need for development of advanced radio-frequency (RF) pulse techniques in modern magnetic resonance imaging (MRI) systems driven by recent advancements in ultra-high magnetic field systems, new parallel transmit/receive coil designs, and accessible powerful computational facilities. 2D spatially selective RF pulses are an example of advanced pulses that have many applications of clinical relevance, e.g., reduced field of view imaging, and MR spectroscopy. The 2D spatially selective RF pulses are mostly generated and optimised with numerical methods that can handle vast controls and multiple constraints. With this study we aim at demonstrating that numerical, optimal control (OC) algorithms are efficient for the design of 2D spatially selective MRI experiments, when robustness towards e.g. field inhomogeneity is in focus. We have chosen three popular OC algorithms; two which are gradient-based, concurrent methods using first- and second-order derivatives, respectively; and a third that belongs to the sequential, monotonically convergent family. We used two experimental models: a water phantom, and an in vivo human head. Taking into consideration the challenging experimental setup, our analysis suggests the use of the sequential, monotonic approach and the second-order gradient-based approach as computational speed, experimental robustness, and image quality is key. All algorithms used in this work were implemented in the MATLAB environment and are freely available to the MRI community.

  6. 2D and 3D MRI features of classic bladder exstrophy

    The bladder exstrophy–epispadias complex (EEC) represents a spectrum of rare and surgically correctable congenital anomalies. Classic bladder exstrophy (CBE) stands between epispadias and cloacal exstrophy (CE) in the severity spectrum, and is the most commonly encountered type. CBE involves congenital defects of the bladder, abdominal wall, pelvic floor, and bony pelvis. With the growing understanding of the detrimental effects of radiation in children, magnetic resonance imaging (MRI) is progressively been utilized in the preoperative work-up and post-surgical follow-up of these patients. MRI provides valuable information for planning and evaluating the optimal surgical techniques for closure of CBE. The aim of this paper is to provide a review of the two- (2D) and three-dimensional (3D) MRI features of CBE including a detailed analytical description of the anatomy of the pelvic floor in affected patients

  7. 2D dose distribution images of a hybrid low field MRI-γ detector

    Abril, A.; Agulles-Pedrós, L.

    2016-07-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the 99mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  8. 4D tumor centroid tracking using orthogonal 2D dynamic MRI: Implications for radiotherapy planning

    Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Flammang, Aaron; Shea, Steven M. [Center for Applied Medical Imaging, Siemens Corporation, Corporate Technology, Baltimore, Maryland 21205 (United States); Hales, Russell; Herman, Joseph; Lee, Junghoon; McNutt, Todd; Roland, Teboh; Wong, John [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States)

    2013-09-15

    Purpose: Current pretreatment, 4D imaging techniques are suboptimal in that they sample breathing motion over a very limited “snapshot” in time. Heretofore, long-duration, 4D motion characterization for radiotherapy planning, margin optimization, and validation have been impractical for safety reasons, requiring invasive markers imaged under x-ray fluoroscopy. To characterize 3D tumor motion and associated variability over durations more consistent with treatments, the authors have developed a practical dynamic MRI (dMRI) technique employing two orthogonal planes acquired in a continuous, interleaved fashion.Methods: 2D balanced steady-state free precession MRI was acquired continuously over 9–14 min at approximately 4 Hz in three healthy volunteers using a commercial 1.5 T system; alternating orthogonal imaging planes (sagittal, coronal, sagittal, etc.) were employed. The 2D in-plane pixel resolution was 2 × 2 mm{sup 2} with a 5 mm slice profile. Simultaneous with image acquisition, the authors monitored a 1D surrogate respiratory signal using a device available with the MRI system. 2D template matching-based anatomic feature registration, or tracking, was performed independently in each orientation. 4D feature tracking at the raw frame rate was derived using spline interpolation.Results: Tracking vascular features in the lung for two volunteers and pancreatic features in one volunteer, the authors have successfully demonstrated this method. Registration error, defined here as the difference between the sagittal and coronal tracking result in the SI direction, ranged from 0.7 to 1.6 mm (1σ) which was less than the acquired image resolution. Although the healthy volunteers were instructed to relax and breathe normally, significantly variable respiration was observed. To demonstrate potential applications of this technique, the authors subsequently explored the intrafraction stability of hypothetical tumoral internal target volumes and 3D spatial probability

  9. 4D tumor centroid tracking using orthogonal 2D dynamic MRI: Implications for radiotherapy planning

    Purpose: Current pretreatment, 4D imaging techniques are suboptimal in that they sample breathing motion over a very limited “snapshot” in time. Heretofore, long-duration, 4D motion characterization for radiotherapy planning, margin optimization, and validation have been impractical for safety reasons, requiring invasive markers imaged under x-ray fluoroscopy. To characterize 3D tumor motion and associated variability over durations more consistent with treatments, the authors have developed a practical dynamic MRI (dMRI) technique employing two orthogonal planes acquired in a continuous, interleaved fashion.Methods: 2D balanced steady-state free precession MRI was acquired continuously over 9–14 min at approximately 4 Hz in three healthy volunteers using a commercial 1.5 T system; alternating orthogonal imaging planes (sagittal, coronal, sagittal, etc.) were employed. The 2D in-plane pixel resolution was 2 × 2 mm2 with a 5 mm slice profile. Simultaneous with image acquisition, the authors monitored a 1D surrogate respiratory signal using a device available with the MRI system. 2D template matching-based anatomic feature registration, or tracking, was performed independently in each orientation. 4D feature tracking at the raw frame rate was derived using spline interpolation.Results: Tracking vascular features in the lung for two volunteers and pancreatic features in one volunteer, the authors have successfully demonstrated this method. Registration error, defined here as the difference between the sagittal and coronal tracking result in the SI direction, ranged from 0.7 to 1.6 mm (1σ) which was less than the acquired image resolution. Although the healthy volunteers were instructed to relax and breathe normally, significantly variable respiration was observed. To demonstrate potential applications of this technique, the authors subsequently explored the intrafraction stability of hypothetical tumoral internal target volumes and 3D spatial probability

  10. Virtual colonoscopy with multi-slice computed tomography

    Subject: Using multi-slice computed tomography (MSCT) large body areas can scanned with high spatial resolution. In this study, MSCT was employed for virtual colonoscopy in various pathologies of the colon. Results: Nine polyps and four of five colon carcinomas were detected using MSCT virtual colonoscopy. In three patients with ulcerative colitis virtual coloscopy revealed morphological alterations compatible with this disease. In two of four patients with multiple diverticula of the colon the true extent of the disorder could be assessed in virtual colonoscopy. (orig.)

  11. Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data

    van der Bom, M. J.; Pluim, J. P. W.; Gounis, M. J.; van de Kraats, E. B.; Sprinkhuizen, S. M.; Timmer, J.; Homan, R.; Bartels, L. W.

    2011-02-01

    Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data is not a trivial task because of their fundamental difference in tissue contrast. This paper presents a technique that generates pseudo-computed tomography (CT) data from multi-spectral MRI acquisitions which is sufficiently similar to real CT data to enable registration of x-ray to MRI with comparable accuracy as registration of x-ray to CT. The method is based on a k-nearest-neighbors (kNN)-regression strategy which labels voxels of MRI data with CT Hounsfield Units. The regression method uses multi-spectral MRI intensities and intensity gradients as features to discriminate between various tissue types. The efficacy of using pseudo-CT data for registration of x-ray to MRI was tested on ex vivo animal data. 2D-3D registration experiments using CT and pseudo-CT data of multiple subjects were performed with a commonly used 2D-3D registration algorithm. On average, the median target registration error for registration of two x-ray images to MRI data was approximately 1 mm larger than for x-ray to CT registration. The authors have shown that pseudo-CT data generated from multi-spectral MRI facilitate registration of MRI to x-ray images. From the experiments it could be concluded that the accuracy achieved was comparable to that of registering x-ray images to CT data.

  12. Comparison of multi-slice spiral CT versus 3.0 T MR imaging in assessing tumor regression after radiofrequency ablation of hepatocellular carcinomas

    Objective: To assess the diagnostic value of MR imaging in follow-up evaluation of patients with hepatocellular carcinomas (HCC) treated with radiofrequency ablation (RFA) and to compare it with that of multi-slice CT. Methods: From December 2009 to September 2011, there were 48 patients (56 HCCs) treated with RFA after transcatheter arterial chemoembolization (TACE). MR imaging and multi-slice CT were performed for follow-up. Two radiologists independently reviewed these images, detection of residual or recurrent tumor were assessed on a five-point scale and compared with Kappa test and with the method of receiver operating characteristic (ROC) curve analysis. Sensitivity, specificity and accuracy were evaluated. Results: The observer agreement rate for MR imaging was higher (0.925) than for multi-slice CT (0.701, P<0.05). The area under the ROC curve (AUC) of MR imaging (0.987 and 0.971 by two radiologists respectively) was significantly higher than that of CT (0.674 and 0.598 by two radiologists respectively), P<0.05. The sensitivity, specificity and accuracy of detection rate for MRI [100%(22/22), 95.5% (86/90) and 95.5% (107/112), respectively] were significantly different with that for multi-slice CT [40.9% (9/22), 57.8% (52/90) and 60.7% (68/112), respectively]. Conclusion: Diagnostic accuracy and detection rate of residual or recurrent tumor were found to be superior with MR imaging than with multi-slice CT. (authors)

  13. Multi-slice spiral CT diagnosis of carotid body tumor

    Objective: to explore the Multi-slice spiral CT (MSCT) findings of carotid body tumor (CBT). Methods: Twelve cases of CBT proved by surgery were collected in this study and all patients accepted contrast-enhanced MSCT examination. Two-dimensional and three-dimensional post-processing were performed at diagnostic workstation using Aquilion 1.42. The CT features of CBT were analyzed. Results Each of 12 patients had one lesion. All lesions demonstrated well-marginated masses of homogeneous soft- tissue density with CT value within 29-48 HU on pre-enhanced images. All lesions were markedly enhanced with CT value over 200 HU on arterial-phase images, and the density of lesions decreased rapidly on delay- phase images. Twelve lesions were all located at the level of carotid artery bifurcation, 3 of them enveloping common carotid artery and internal/external carotid artery, and other 9 of them riding right on the carotid bifurcation. Internal carotid artery usually were shifted toward posterior-lateral, and external carotid artery toward anterior or anterior-medial. Conclusion: Contrast-enhanced MSCT examination not only can make a qualitative diagnosis of CBT, but determine its accurate location. It plays an importantly instructional role in clinical diagnosis and treatment. (authors)

  14. Multi-slice spiral CT of living-related liver transplantation in children: pictorial essay

    In pediatric living-related liver transplantation, preoperative evaluation of the recipient is important for surgical planning, while the accurate diagnosis of postoperative complications is essential for graft salvage. Multiplanar and three dimensional imaging using multi-slice spiral CT can be used for preoperative vascular imaging, as well as for evaluating postoperative complications. In this essay, we describe the usefulness of multi-slice CT, combined with a variety of different reconstruction techniques, for the preoperative evaluation of transplant recipients. In addition, we demonstrate the multi-slice CT findings of postoperative complications, including vascular stenosis or thrombosis, bile duct leak or stricture, and extrahepatic fluid collection

  15. Multi-slice spiral CT of living-related liver transplantation in children: pictorial essay

    Choi, Seong Hoon; Goo, Hyun Woo; Yoon, Chong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Ulsan (Korea, Republic of)

    2004-09-15

    In pediatric living-related liver transplantation, preoperative evaluation of the recipient is important for surgical planning, while the accurate diagnosis of postoperative complications is essential for graft salvage. Multiplanar and three dimensional imaging using multi-slice spiral CT can be used for preoperative vascular imaging, as well as for evaluating postoperative complications. In this essay, we describe the usefulness of multi-slice CT, combined with a variety of different reconstruction techniques, for the preoperative evaluation of transplant recipients. In addition, we demonstrate the multi-slice CT findings of postoperative complications, including vascular stenosis or thrombosis, bile duct leak or stricture, and extrahepatic fluid collection.

  16. Three-dimensional image reconstruction for PET by multi-slice rebinning and axial image filtering.

    Lewittt, R M; Muehllehner, G; Karpt, J S

    1994-03-01

    A fast method is described for reconstructing volume images from three-dimensional (3D) coincidence data in positron emission tomography (PET). The reconstruction method makes use of all coincidence data acquired by high-sensitivity PET systems that do not have inter-slice absorbers (septa) to restrict the axial acceptance angle. The reconstruction method requires only a small amount of storage and computation, making it well suited for dynamic and whole-body studies. The method consists of three steps: (i) rebinning of coincidence data into a stack of 2D sinograms; (ii) slice-by-slice reconstruction of the sinogram associated with each slice to produce a preliminary 3D image having strong blurring in the axial (z) direction, but with different blurring at different z positions; and (iii) spatially variant filtering of the 3D image in the axial direction (i.e. 1D filtering in z for each x-y column) to produce the final image. The first step involves a new form of the rebinning operation in which multiple sinograms are incremented for each oblique coincidence line (multi-slice rebinning). The axial filtering step is formulated and implemented using the singular value decomposition (SVD). The method has been applied successfully to simulated data and to measured data for different kinds of phantom (multiple point sources, multiple discs, a cylinder with cold spheres, and a 3D brain phantom). PMID:15551583

  17. How will the introduction of multi-slice CT affect patient doses?

    Imaging protocols for patients undergoing CT examinations on a conventional single section scanner (GE CT/i) were compared with those developed after a multi-slice scanner (GE LightSpeed) was introduced into clinical practice. For multi-slice CT, the reduction in patient scan time was a more than a factor of two for head scans, and approximately 25% for body scans. The number of images available for review on the multi-slice CT system increased by approximately 40%. Use of this multi-slice CT scanner resulted in an effective dose of 1.2 mSv for head examinations and 9.1 mSv for body examinations. The increase in patient effective dose after the introduction of multi-slice CT was approximately 30% for head CT examinations and 150% for body examinations. Higher patient doses were due to a shorter CT geometry, x-ray beam profiles that are greater than the detector width, and the use of a pitch ratio of only 0.75. Since multi-slice CT offers major reductions in scan time as well as improved image quality, it is anticipated that both individual and collective doses from CT will continue to increase for the foreseeable future. (author)

  18. Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

    Meckel, Stephan [University Hospital Freiburg, Department of Neuroradiology, Freiburg (Germany); Leitner, Lorenz; Schubert, Tilman [University Hospital Basel, Institute of Radiology, Basel (Switzerland); Bonati, Leo H.; Lyrer, Philippe [University Hospital Basel, Department of Neurology, Basel (Switzerland); Santini, Francesco [University Hospital Basel, Department of Radiological Physics, Institute of Radiology, Basel (Switzerland); Stalder, Aurelien F. [Xuanwu Hospital - Capital Medical University, Department of Radiology, Beijing (China); Markl, Michael [Northwestern University Feinberg School of Medicine, Departments of Radiology and Biomedical Engineering, Chicago (United States); Wetzel, Stephan G. [Neuroradiology, Swiss Neuro Institute, Klinik Hirslanden, Zurich (Switzerland)

    2013-04-15

    4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

  19. Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

    4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

  20. Design of a 2D MRI compatible robot for performing prostate cancer treatment using therapeutic ultrasound

    Yiallouras, Christos

    2015-01-01

    Therapeutic ultrasound is a promising treatment method for many common cancers, including prostate cancer. Magnetic resonance image (MRI) guidance of therapeutic ultrasound permits targeting and monitoring of therapy. In this thesis a prototype MRI compatible positioning device for the treatment of prostate cancer using therapeutic ultrasound is presented. The accuracy, MRI compatibility and functionality of the positioning device was evaluated in in vitro experiments (using gel phantoms and ...

  1. Comparison of 3D and 2D FSE T2-weighted MRI in the diagnosis of deep pelvic endometriosis: Preliminary results

    Aim: To evaluate image quality and diagnostic accuracy of two- (2D) and three-dimensional (3D) T2-weighted magnetic resonance imaging (MRI) for the evaluation of deep infiltrating endometriosis (DIE). Materials and methods: One hundred and ten consecutive patients with suspicion of endometriosis were recruited at two institutions over a 5-month period. Twenty-three women underwent surgery, 18 had DIE at histology. Two readers independently evaluated 3D and 2D MRI for image quality and diagnosis of DIE. Descriptive analysis, chi-square test for categorical or nominal variables, McNemar test for comparison between 3D and 2D T2-weighted MRI, and weighted “statistics” for intra- and interobserver agreement were used for statistical analysis. Results: Both readers found that 3D yielded significantly lower image quality than 2D MRI (p < 0.0001). Acquisition time for 3D was significantly shorter than 2D MRI (p < 0.01). 3D offered similar accuracy to diagnose DIE compared to 2D MRI. For all locations of endometriosis, a high or variable intra-observer agreement was observed for reader 1 and 2, respectively. Conclusions: Despite a lower overall image quality, 3D provides significant time saving and similar accuracy than multiplanar 2D MRI in the diagnosis of specific DIE locations.

  2. Multi-slice CT-colonography in low-dose technique - preliminary results

    Purpose: Assessment of multi-slice CT-colonography (MSCTC) with standard and low-dose technique in comparison to conventional colonoscopy (CC). Materials and Methods: After standardized bowel cleansing, 28 men and 24 women (mean age 60,3 years) underwent CC within two hours after MSCTC had been performed (4 x 2.5 mm collimation, 3 mm slice width, 17.5 mm table feed, 120 kVp). In 19 patients, MSCTC was performed with 120 mAs (CTDIw,eff: 11.28 mGy), and in 33 patients with 10 mAs (CTDIw,eff: 0.94 mGy), respectively. After noise reduction using mathematical algorithms by a dedicated software (ECCET), images were analyzed by two blinded readers in simultaneously displayed 2D- and 3D-modes. Findings in MSCTC were compared to the results obtained with CC. Results: Calculated effective doses ranged between 9 and 12 mSv for 120 mAs, and between 0.75 and 1 mSv for the low-dose technique. In standard dose MSCTC, 20 of 25 lesions (80%) were found: all 7 tumors (100%), one large polyp (> 10 mm; 100%), 6 of 7 medium sized polyps (9.9 to 5 mm; 86%) and 6 of 10 small polyps (< 5 mm; 60%). In low-dose MSCTC, 32 of 44 lesions (73%) were seen: all three large polyps (100%), 13 of 14 medium sized polyps (93%) and 16 of 27 small polyps (59%). An overall sensitivity of 78% with a specificity of 68% was calculated. False positive findings were seen mostly for small lesions (12 for standard dose, 11 for low-dose). Conclusion: Despite a 12-fold reduction of radiation exposure, MSCTC in low-dose technique performs comparably well to standard dose MSCTC. After mathematical noise reduction, more than 90% of polyps larger than 5 mm can be detected. (orig.)

  3. Fast Measurement of Intracardiac Pressure Differences With 2D Breath-Hold Phase-Contrast MRI

    Thompson, Richard B; Mcveigh, Elliot R.

    2003-01-01

    Intracardiovascular blood pressure differences can be derived from velocity images acquired with phase-contrast (PC) MRI by evaluating the Navier-Stokes equations. Pressure differences within a slice of interest can be calculated using only the in-plane velocity components from that slice. This rapid exam is proposed as an alternative to the lengthy 3D velocity imaging exams. Despite their good spatial coverage, the 3D exams are prone to artifacts and errors from respiratory motion and insuff...

  4. Flow Quantification from 2D Phase Contrast MRI in Renal Arteries Using Clustering

    Zöllner, Frank G.; Monnsen, Jan Ankar; Lundervold, Arvid; Rørvik, Jarle

    We present an approach based on clustering to segment renal arteries from 2D PC Cine MR images to measure blood velocity and flow. Such information are important in grading renal artery stenosis and support the decision on surgical interventions like percutan transluminal angioplasty. Results show that the renal arteries could be extracted automatically and the corresponding velocity profiles could be calculated. Furthermore, the clustering could detect possible phase wrap effects automatically as well as differences in the blood flow patterns within the vessel.

  5. Multi-slice 3D-CTA - an improvement over single slice helical CTA for cerebral aneurysms

    The aim of this study was to demonstrate the utility of volume rendered multi-slice helical three-dimensional CT angiography in patients with cerebral aneurysm when compared with single slice CT angiography and formal digital subtraction angiography. A prototype Toshiba Aquilon multi-slice CT scanner was employed with the following scan conditions: voltage 135 kV; current 300 mA; slice thickness 0.8 mm; scan speed 0.75 sec/cycle; couch speed 1 mm/sec; range 50 mm from foramen magnum; scan pitch 3; three dimensional images were reconstructed using multiple image projections and integral volume rendering algorithms on a Xlink/Xtension workstation. 80 cases of multi-slice CTA for cerebral aneurysm carried out at Fujita University from January 1999 to January 2001 were reviewed. The advantages of multi-slice imaging are illustrated with representative cases of cerebral aneurysm - good demonstration of three dimensional anatomy, appreciation of perforators down to 1 mm in size, delineation of the vessels around the aneurysm complex, relationship between the aneurysm and skull base, information on calcification, thrombus and blebs in the wall and eleven routine views for perusal. Multi-slice CTA is a significant improvement over single slice CTA for cerebral aneurysms. It is our experience the superior and precise images produced by multi-slice technology displays anatomical information not readily available from standard DSA. Multislice 3D-CTA is relatively non-invasive and provides better and adequate detail for surgical planning. The basis of multi-slice CT angiography is described. Multi slice CTA is changing the way cerebral aneurysms are being managed nowadays. New advances in the technology of multi-slice CTA resulting in increased image resolution are outlined. (author)

  6. Multi-slice spiral CT and pathological correlation of renal cell carcinoma

    Objective: To analyze relationship between characteristics on multi-slice spiral CT (MSCT) and pathology of renal cell carcinoma. Methods: Multi-slice spiral CT and surgical pathological results on 32 cases of renal cell carcinoma were retrospectively analyzed. Results: Of the 32 cases, 28 were pathologically diagnosed as clear cell carcinoma, with tumor contrast enhancement similar to the normal cortex in the renal cortical phase (146-175HU), slight contrast washout in the renal parenchyma phase and significant contrast washout from the tumor in the pyelographic phase. Granular cell carcinoma in 4 patients showed no or mild contrast enhancement (38- 55HU) in all three phase. The overall diagnostic accordance rate was 100%, with preoperative staging accordance rate of 96.42%. Conclusion: The triple-phase contrast-enhanced MSCT is useful in predicting the tumor cell type and staging of renal cell carcinoma. (authors)

  7. Improvement of Efficiency and Flexibility in Multi-slice Helical CT

    SUN Wen-wu; CHEN Si-ping; ZHUANG Tian-ge

    2008-01-01

    One of the main aspects in computed tomography (CT) development is to make CT rapidly scan a large longitudinal volume with high z-axis resolution. The combination of helical scanning with multi-slice CT is a promising approach. Image reconstruction in multi-slice CT becomes, therefore, the major challenge. Known algorithms need to derive the complementary data or work only for certain range of pitches. A reconstruction algorithm was presented that works with the direct data as well as arbitrary pitches. Filter interpolation based on the proposed method was implemented easy. The results of computer simulations under kinds of conditions for four-slice CT were presented. The proposed method can obtain higher efficiency than the conventional method.

  8. Diagnosis on multi-slice spiral CT in acute pancreatitis and complications

    Objective: To analyze multi-slice CT features and to assess the diagnostic value of CT in acute pancreatitis. Methods: CT was performed on 21 patients with acute pancreatitis in the unenhanced, arterial (28 seconds after intravenous contrast injection), venous (60 seconds) phases. The morphology and contrast enhancement enhancement patterns were analyzed. Results: Of 21 patients, pancreatic necrosis was found in 9 and acute edematous pancreatitis in 12. Associated findings included bile duct stones or cholecystitis (13), liver abscess (1), systemic lupus erythematosis (1), abdominal trauma (2), and pancreatic divisum (1). Complications included pseudoaneurysm (1), venous thrombosis (1), ascites (7), pleural effusion (4) and right lower lobe lung atelectasis (1). Conclusion: Tri-phasic multi-slice spiral CT can accurately distinguish acute edematous pancreatitis from acute hemorrhagic necrotic pancreatitis. CT allows comprehensive evaluation of the cause and complication of acute pancreatitis. (authors)

  9. Multi-slice computed tomography assessment of bronchial compression with absent pulmonary valve

    Zhong, Yu-Min; Sun, Ai-Min; Wang, Qian; Zhu, Ming; Qiu, Hai-Sheng [Shanghai Children' s Medical Center and Shanghai Jiao Tong University Medical School, Department of Radiology, Shanghai (China); Jaffe, Richard B. [Primary Children' s Medical Center, Department of Medical Imaging, Salt Lake City, UT (United States); Liu, Jin-Fen [Shanghai Children' s Medical Center, Department of Cardiothoracic Surgery, Shanghai (China); Gao, Wei [Shanghai Children' s Medical Center and Shanghai Jiao Tong University Medical School, Department of Cardiology, Shanghai (China); Berdon, Walter E. [Children' s Hospital of New York, Department of Radiology, New York, NY (United States)

    2014-07-15

    Absent pulmonary valve is a rare cardiovascular anomaly that can result in profound tracheobronchial compression. To demonstrate the advantage of multi-slice CT in diagnosing tracheobronchial compression, its severity as related to the adjacent dilated pulmonary arteries, and associated lung and cardiac lesions. We included children with absent pulmonary valve who were reviewed by multi-slice CT during a 17-year period. The number and locations of stenoses and lung lesions were noted and the severity of stenosis was categorized. The diameter of the pulmonary artery was measured and associated cardiac defects were demonstrated. Thirty-one children (14 girls and 17 boys) were included. Of these, 29 had ventricular septal defect and 2 had an intact ventricular septum. Twenty-nine children (94%) had tracheobronchial compression, judged to be mild in nine children (31%), moderate in 10 (34%) and severe in 10 (34%). The different locations of the stenosis (carina, main bronchi, lobar and segmental bronchi) were observed. And the number and location of lung lesions demonstrated that the right middle and left upper and lower lobes were often affected. The diameter of the pulmonary artery in these children was well above normal published values, and Spearman rank correlation analysis showed a correlation between the size of the pulmonary artery and the severity of the tracheobronchial stenosis. Nineteen children (61%) underwent surgery and 4 of these children had a multi-slice CT post-operative follow-up study. Absent pulmonary valve can cause significant morbidity and mortality in children. Multi-slice CT can accurately depict areas of tracheobronchial compression, associated lung lesions and cardiac defects, helping to direct the surgeon. (orig.)

  10. Evaluation of intestinal tuberculosis by multi-slice computed tomography enterography

    Zhao, Jing; Cui, Min-Yi; Chan, Tao; Mao, Ren; Luo, Yanji; Barua, Indira; Chen, Minhu; Li, Zi-Ping; Feng, Shi-Ting

    2015-01-01

    Background Multi-slice computed tomography enterography (MSCTE) is now widely used to diagnose and monitor intestinal disease. Preliminary studies suggest that MSCTE may be useful in detecting intestinal tuberculosis (ITB). We sought to assess the use of MSCTE for the diagnosis of ITB in our medical center. Methods In this retrospective study, 15 patients (11 males and 4 females, 6 to 65 years old) were enrolled and diagnosed with ITB by MSCTE. Diagnosis were confirmed by pathology or clinica...

  11. Multi-slice computed tomography assessment of bronchial compression with absent pulmonary valve

    Absent pulmonary valve is a rare cardiovascular anomaly that can result in profound tracheobronchial compression. To demonstrate the advantage of multi-slice CT in diagnosing tracheobronchial compression, its severity as related to the adjacent dilated pulmonary arteries, and associated lung and cardiac lesions. We included children with absent pulmonary valve who were reviewed by multi-slice CT during a 17-year period. The number and locations of stenoses and lung lesions were noted and the severity of stenosis was categorized. The diameter of the pulmonary artery was measured and associated cardiac defects were demonstrated. Thirty-one children (14 girls and 17 boys) were included. Of these, 29 had ventricular septal defect and 2 had an intact ventricular septum. Twenty-nine children (94%) had tracheobronchial compression, judged to be mild in nine children (31%), moderate in 10 (34%) and severe in 10 (34%). The different locations of the stenosis (carina, main bronchi, lobar and segmental bronchi) were observed. And the number and location of lung lesions demonstrated that the right middle and left upper and lower lobes were often affected. The diameter of the pulmonary artery in these children was well above normal published values, and Spearman rank correlation analysis showed a correlation between the size of the pulmonary artery and the severity of the tracheobronchial stenosis. Nineteen children (61%) underwent surgery and 4 of these children had a multi-slice CT post-operative follow-up study. Absent pulmonary valve can cause significant morbidity and mortality in children. Multi-slice CT can accurately depict areas of tracheobronchial compression, associated lung lesions and cardiac defects, helping to direct the surgeon. (orig.)

  12. Detection of irregular, transient fMRI activity in normal controls using 2dTCA: comparison to event-related analysis using known timing

    Morgan, Victoria L.; John C Gore

    2009-01-01

    When events occur spontaneously during the acquisition of a series of images, traditional modeling methods for detecting functional MRI activation detection cannot be employed. The two-dimensional Temporal Clustering Algorithm, 2dTCA, has been shown to accurately detect random, transient activations in computer simulations without the use of known event timings. In this study we applied the 2dTCA technique to detect the timings and spatial locations of sparse, irregular, transient activations...

  13. Diagnosis of pulmonary embolism and the underlying venous thrombosis by multi-slice CT

    To determine the value of multi-slice CT for the diagnosis of acute pulmonary embolism and an underlying venous thrombosis. Methods: 70 patients with clinically suspected acute pulmonary embolism were examined. Using multi-slice CT a combined examination of the pulmonary arteries and the veins of the lower limb, pelvis and abdomen was performed. Only one single bolus of 150 ml iopromid 300 was injected into a cubital vein with a flow of 4 ml/s. First, the pulmonary arteries were scanned with a slice thickness of 2.5 mm and a pitch of 1.5. On arrival of the contrast medium at the popliteal veins, indicated by bolus trakking, the veins of the lower limbs up to the end of the inferior vena cava were imaged using a slice thickness of 3.75 mm and a pitch of 1.5. The results could be compared with a ventilation-perfusion scan in 48 cases, with a Doppler ultrasound examination in 46 cases, and with a venography in 10 cases. Furthermore, the image quality of all arterial and venous regions was subjectively assessed. Results: In all patients who underwent multi-slice CT the pulmonary arteries as well as the veins of the lower half of the body could be recorded completely. Regarding the pulmonary arteries the image quality showed excellent results for the central and segmental arteries. The region up to the 3rd division in subsegmental branches could be sufficiently judged. More peripherally, a diagnostic assessment was not possible. The image quality of the veins was excellent in all sections, except the calf, where a reliable diagnosis could not be made. The comparison with the other techniques confirmed the superiority of multi-slice CT concerning the central and segmental pulmonary arteries and the veins from the popliteal vein to the inferior vena cava. In contrast, peripheral pulmonary emboli can be detected more certainly in ventilation/perfusion scans. The veins of the calf can be evaluated more reliably with venography. (orig.)

  14. Quantitative analyzation of bronchial wall regions using multi slice CT images

    As multi-slice CT develops, there are great expectations for an automatic and computer-support diagnoses. This research is on bronchial area which is composed of the bronchial wall regions and the air regions in the internal bronchial tube. Since to diagnose this is difficult, support diagnosis using CT images is desired. The thickness of bronchial wall changes as the airway of early lung cancer, bronchial asthma and the bronchial enhancing syndrome and others changes into a malignant state. These changes are detected and the thickness of bronchial wall becomes important information. In this research, the extraction accuracy of the algorithm for bronchial wall evaluation is good. (author)

  15. Detection of malignant right coronary artery anomaly by multi-slice CT coronary angiography

    Coronary artery anomalies occur in 0.3-0.8% of the population and infer a high risk for sudden cardiac death in young adults. Diagnosis is usually established during coronary angiography, which is hampered by poor spatial visualization. Magnetic resonance imaging is an alternative, but it is not feasible in the presence of metal objects or claustrophobia. In this report, a 15-year-old boy experienced ventricular fibrillation and was successfully resuscitated. Cardiac catheterization was inconclusive, and pacemaker implantation prohibited the use of MR imaging. Multi-slice CT coronary angiography revealed a malignant anomalous right coronary artery. (orig.)

  16. Exploiting sparsity and low-rank structure for the recovery of multi-slice breast MRIs with reduced sampling error.

    Yin, X X; Ng, B W-H; Ramamohanarao, K; Baghai-Wadji, A; Abbott, D

    2012-09-01

    It has been shown that, magnetic resonance images (MRIs) with sparsity representation in a transformed domain, e.g. spatial finite-differences (FD), or discrete cosine transform (DCT), can be restored from undersampled k-space via applying current compressive sampling theory. The paper presents a model-based method for the restoration of MRIs. The reduced-order model, in which a full-system-response is projected onto a subspace of lower dimensionality, has been used to accelerate image reconstruction by reducing the size of the involved linear system. In this paper, the singular value threshold (SVT) technique is applied as a denoising scheme to reduce and select the model order of the inverse Fourier transform image, and to restore multi-slice breast MRIs that have been compressively sampled in k-space. The restored MRIs with SVT for denoising show reduced sampling errors compared to the direct MRI restoration methods via spatial FD, or DCT. Compressive sampling is a technique for finding sparse solutions to underdetermined linear systems. The sparsity that is implicit in MRIs is to explore the solution to MRI reconstruction after transformation from significantly undersampled k-space. The challenge, however, is that, since some incoherent artifacts result from the random undersampling, noise-like interference is added to the image with sparse representation. These recovery algorithms in the literature are not capable of fully removing the artifacts. It is necessary to introduce a denoising procedure to improve the quality of image recovery. This paper applies a singular value threshold algorithm to reduce the model order of image basis functions, which allows further improvement of the quality of image reconstruction with removal of noise artifacts. The principle of the denoising scheme is to reconstruct the sparse MRI matrices optimally with a lower rank via selecting smaller number of dominant singular values. The singular value threshold algorithm is performed

  17. Functional MRI of the pharynx in obstructive sleep apnea (OSA) with rapid 2-D flash sequences; Funktionelle MRT des Pharynx bei obstruktiver Schlafapnoe (OSA) mit schnellen 2D-FLASH-Sequenzen

    Jaeger, L. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Guenther, E. [Klinik und Poliklinik fuer Hals-, Nasen- und Ohrenkranke, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Gauger, J. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Nitz, W. [Siemens Medizintechnik, Erlangen (Germany); Kastenbauer, E. [Klinik und Poliklinik fuer Hals-, Nasen- und Ohrenkranke, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Reiser, M. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany)

    1996-03-01

    Functional imaging of the pharynx used to be the domain of cineradiography, CT and ultrafast CT. The development of modern MRI techniques led to new access to functional disorders of the pharynx. The aim of this study was to implement a new MRI technique to examine oropharyngeal obstructive mechanisms in patients with obstructive sleep apnea (OSA). Sixteen patients suffering from OSA and 6 healthy volunteers were examined on a 1.5 T whole-body imager (`Vision`, Siemens, Erlangen Medical Engineering, Germany) using a circular polarized head coil. Imaging was performed with 2D flash sequences in midsagittal and axial planes. Patients and volunteers were asked to breathe normally through the nose and to simulate snoring and the Mueller maneuver during magnetic resonance imaging (MRI). Prior to MRI, all patients underwent an ear, nose and throat (ENT) examination, functional fiberoptic nasopharyngoscopy and polysomnography. A temporal resolution of 6 images/s and an in-plane resolution of 2.67x1.8 mm were achieved. The mobility of the tongue, soft palate and pharyngeal surface could be clearly delineated. The MRI findings correlated well with the clinical examinations. We propose ultrafast MRI as a reliable and non-invasive method of evaluating pharyngeal obstruction and their levels. (orig.) [Deutsch] Die funktionelle Bildgebung des Pharynx war bisher eine Domaene der Hochfrequenzroentgenkinematographie, der Computertomographie (CT) und der ultraschnellen Computertomographie. Die Entwicklung moderner Techniken in der Magnetresonanztomographie (MRT) fuehrte zu neuen Ansaetzen in der Diagnostik pharyngealer Dysfunktionen. Ziel der vorliegenden Studie war die Implementierung neuer schneller MR-Sequenzen, um Verschlussmechanismen entlang des Pharnyxschlauches bei Patienten mit obstruktiver Schlafapnoe (OSA) zu untersuchen. 16 Patienten mit OSA und 6 gesunde Probanden wurden an einem 1,5-T-Ganzkoerpermagnetresonanztomographen (`Vision`, Siemens Medizintechnik, Erlangen

  18. The clinical application of multi-slice spiral CT angiography in abdominal aortic disease

    2005-01-01

    Objective: To evaluate the clinical application of multi-slice spiral CT angiography(MSCTA) in the assessment of abdominal aortic disease. Methods: Fifty-four patients underwent multi-slice spiral CT angiography of abdomen. Contrast agent (Omnipaque 300 I g/L) 1.5 ml/kg was injected and the injection rate was 3 ml/s. The delay time was determined by bolus tracking technique,Tll level abdominal aorta was set as the target vessel and the threshold was 180-200 Hu, slice width was 3 mm and with a pitch of 4-6.Original data were transferred to working-station to perform functional reconstruction. Results: Ten cases were normal, twenty-eight cases were abdominal aortic aneurysms, five abdominal aortic dissecting aneurysms (Debakay type Ⅲ ) and eleven aortic sclerosis. SSD showed the body of aneurysm and the relationship between aneurysm and adjacent blood vessel, MIP better displayed calcification of blood vessel wall and condition of the stent, MPR demonstrated true and false lumen, rupture site of abdominal aorta intima and mural thrombus. Conclusion: MSCTA axial and reconstruction image can show the extent of abdominal aortic disease and the relationship with adjacent blood vessels. It is a safe, simple and non-invasive examination method.

  19. Proximal arterioportal shunt in hepatocellular carcinoma: multi-slice spiral CT features and its clinical significance

    Objective: To evaluate the dynamic enhanced multi-slice spiral CT features and the formative mechanisms of proximal arterioportal shunt (APS) associated with hepatocellular carcinoma (HCC), and to assess the CT diagnostic ability and clinical value for proximal APS by comparing with digital subtraction angiography (DSA). Methods: One hundred and sixty-eight patients with HCC received both dynamic enhanced multi-slice spiral CT scan and DSA of the liver, and the time lapse between these two examinations was from 3 to 15 days. Of the 168 patients, 37 were massive tumors, 102 were nodular, and 29 were diffuse, respectively. Spiral CT signs and its diagnostic ability for proximal APS were analyzed and compared with the golden standard of DSA. Peripheral hepatic segmental or subsegmental small APS were excluded in our study. Results: Of the 168 patients with HCC, 42 (25.0%) were demonstrated to have proximal APS on DSA , and all the of 42 patients had positive CT findings related to proximal APS in arterial phase. Of the 6 patients proved to have false positive CT signs, 2 showed lower enhancement of portal vein (PV) than that of the aorta. The sensitivity, specificity, accuracy, and positive and negative predictive value of spiral CT in diagnosing proximal APS were 100.0%, 95.2 %, 96.4%, 87.5% and 100.0 %, respectively. There was a good correlation on the extent of APS to main PV, left or right PV, superior mesenteric vein, splenic vein, and coronary vein between CT and DSA in 35 patients (83.3%). The extent of APS to main PV and left or right PV was well correlated between CT and DSA in 38 patients (90.5%). The direct CT signs of proximal APS in arterial phase were revealed as early and strong enhancement of main PV and/or left or right PV approaching the density of the aorta (n=38). The indirect CT signs of proximal APS in arterial phase were demonstrated as high attenuation of normal hepatic parenchyma in the lobar distribution ipsilateral to the tumor (n=4

  20. The clinical value of combined use of MR imaging and multi-slice spiral CT in limb salvage surgery for orthopaedic oncology patients: initial experience in nine patients

    The purpose of this prospective study was to evaluate the value of the combined use of MR imaging and multi-slice spiral CT for limb salvage surgery in orthopaedic oncology patients. Nine consecutive patients with lower/upper limb malignant bone tumours (7 osteosarcomas and 2 chondrosarcomas) were treated with limb-salvaging procedures. Preoperative planning including determination of the osteotomy plane and diameters of the prosthesis was performed basing on the preoperative CT and MR images. The histopathology was performed as golden diagnostic criteria to evaluate the accuracy of CT and MR-based determination for tumour’s boundary. The tumour extension measured on MRI was consistent with the actual extension (P>0.05, paired Student’s t test), while the extension measured on CT imaging was less than the actual extension. The length, offset and alignment of the affected limb were reconstructed accurately after the operation. An excellent functional outcome was achieved in all patients. In the present study, MRI was found to be superior to CT for determining the tumour extension, combined use of MRI and CT measurement provided high precision for the fit of the prosthesis and excellent functional results

  1. Comparison of 3D turbo spin-echo SPACE sequences with conventional 2D MRI sequences to assess the shoulder joint

    Highlights: • 3D SPACE and conventional 2D TSE MRI for assessment of the shoulder joint were compared. • Concordance for most pathologys was substantial to almost perfect. • Examination time could be reduced up to 8 min (27%). • Regarding rotator cuff injuries an additional sagittal T2w TSE sequence in 3D protocol is recommended. - Abstract: Purpose: To determine the accuracy and reliability of three-dimensional (3D) T1- and proton density (PD)-weighted turbo spin-echo (TSE) sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) compared with conventional 2D sequences in assessment of the shoulder-joint. Materials and methods: Ninety-three subjects were examined on a 3-T MRI system with both conventional 2D-TSE sequences in T1-, T2- and PD-weighting and 3D SPACE sequences in T1- and PD-weighting. All examinations were assessed independently by two reviewers for common pathologies of the shoulder-joint. Agreement between 2D- and 3D-sequences and inter-observer-agreement was evaluated using kappa-statistics. Results: Using conventional 2D TSE sequences as standard of reference, sensitivity, specificity, and accuracy values of 3D SPACE were 81.8%, 95.1%, and 93.5% for injuries of the supraspinatus-tendon (SSP), 81.3%, 93.5%, and 91.4% for the cartilage layer and 82.4%, 98.5%, and 97.5% for the long biceps tendon. Concordance between 2D and 3D was almost perfect for tendinopathies of the SSP (κ = 0.85), osteoarthritis (κ = 1), luxation of the biceps tendon (κ = 1) and adjacent bone marrow (κ = 0.92). Inter-observer-agreement was generally higher for conventional 2D TSE sequences (κ, 0.23–1.0), when compared to 3D SPACE sequences (κ, −0.33 to 1.0) except for disorders of the long biceps tendon and supraspinatus tendon rupture. Conclusion: Because of substantial and almost perfect concordance with conventional 2D TSE sequences for common shoulder pathologies, MRI examination-time can be reduced by nearly 40

  2. Comparison of 3D turbo spin-echo SPACE sequences with conventional 2D MRI sequences to assess the shoulder joint

    Kloth, Jost Karsten, E-mail: jost.kloth@med.uni-heidelberg.de [Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg (Germany); Winterstein, Marianne, E-mail: marianne.winterstein@med.uni-heidelberg.de [Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg (Germany); Akbar, Michael, E-mail: michael.akbar@med.uni-heidelberg.de [Orthopedic and Trauma Surgery, University Hospital Heidelberg, Schlierbacher Landstraße 200a, D-69118 Heidelberg (Germany); Meyer, Esther, E-mail: esther.meyer@siemens.com [Siemens Healthcare, Erlangen (Germany); Paul, Dominik, E-mail: dominik.paul@siemens.com [Siemens Healthcare, Erlangen (Germany); Kauczor, Haus-Ulrich, E-mail: hans-ulrich.kauczor@med.uni-heidelberg.de [Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg (Germany); Weber, Marc-André, E-mail: marcandre.weber@med.uni-heidelberg.de [Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg (Germany)

    2014-10-15

    Highlights: • 3D SPACE and conventional 2D TSE MRI for assessment of the shoulder joint were compared. • Concordance for most pathologys was substantial to almost perfect. • Examination time could be reduced up to 8 min (27%). • Regarding rotator cuff injuries an additional sagittal T2w TSE sequence in 3D protocol is recommended. - Abstract: Purpose: To determine the accuracy and reliability of three-dimensional (3D) T1- and proton density (PD)-weighted turbo spin-echo (TSE) sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) compared with conventional 2D sequences in assessment of the shoulder-joint. Materials and methods: Ninety-three subjects were examined on a 3-T MRI system with both conventional 2D-TSE sequences in T1-, T2- and PD-weighting and 3D SPACE sequences in T1- and PD-weighting. All examinations were assessed independently by two reviewers for common pathologies of the shoulder-joint. Agreement between 2D- and 3D-sequences and inter-observer-agreement was evaluated using kappa-statistics. Results: Using conventional 2D TSE sequences as standard of reference, sensitivity, specificity, and accuracy values of 3D SPACE were 81.8%, 95.1%, and 93.5% for injuries of the supraspinatus-tendon (SSP), 81.3%, 93.5%, and 91.4% for the cartilage layer and 82.4%, 98.5%, and 97.5% for the long biceps tendon. Concordance between 2D and 3D was almost perfect for tendinopathies of the SSP (κ = 0.85), osteoarthritis (κ = 1), luxation of the biceps tendon (κ = 1) and adjacent bone marrow (κ = 0.92). Inter-observer-agreement was generally higher for conventional 2D TSE sequences (κ, 0.23–1.0), when compared to 3D SPACE sequences (κ, −0.33 to 1.0) except for disorders of the long biceps tendon and supraspinatus tendon rupture. Conclusion: Because of substantial and almost perfect concordance with conventional 2D TSE sequences for common shoulder pathologies, MRI examination-time can be reduced by nearly 40

  3. A method of predicting the image noise in paediatric multi-slice computed tomography images

    The purpose of this study was to develop an equation with which to determine the tube current to be used in order to obtain a certain image noise level for differently sized children undergoing multi-slice computed tomography examination. The relationship between image noise and detector dose for different examination protocols was established for a LightSpeed Ultra, an eight slice CT from GEMS, using homogeneous water phantoms of different sizes. Three different anatomical areas (head, thorax and abdomen) were studied in 111 patients between 0 and 17 y of age. The mean ratio between the calculated and the measured noise in patient images was established for the different areas. Head examinations showed the best correlation (measured-to-calculated noise ratio = 1.01). In the thorax, the calculated noise was generally higher than the measured noise (ratio = 0.74), and in the abdomen, the opposite result was found (ratio = 1.20). (authors)

  4. Diagnostic value of multi-slice spiral CT angiography in visceral aneurysm

    Objective: To evaluate the diagnostic value of multi-slice spiral CT angiography (MSCTA) in visceral aneurysm. Methods: Unenhanced and contrast-enhanced CT scans in 42 cases of visceral aneurysm were retrospectively analyzed. volume rendering and multiplanar reconstruction were performed to reconstruct the vascular images. Results: The relationship between parent arteries and 58 aneurysms found in 42 patients were displayed clearly. The aneurysms arose from the splenic artery (27, 46.6%), hepatic artery (6, 17.2%), mesenteric artery (7, 12.1%), celiac artery (8, 13.8%). Three of the aneurysms were ruptured (5.2%) and 8 were associated with parent artery stenosis (13.8%). Conclusion: MSCTA clearly depict visceral aneurysm and complications. (authors)

  5. Multi-slice spiral CT angiography: clinical application and the evaluation

    Objective: To evaluate the clinical application of multi-slice spiral CT angiography (MSCTA) in diagnosis of vascular diseases. Methods: Imaging materials of multi-slice spiral CT angiography of 73 cases were retrospectively analyzed, including 27 cases of intracranial vascular CTA, 8 of carotid CTA, 10 of pulmonary artery CTA, 6 of coronary artery CTA, 11 of aortic CTA, and 11 of low extremity artery CTA. After the raw data was reconstructed by overlapping slice-chickness, the axial images were uploaded to workstation for post data processing, and were then evaluated and reconstructed using 3D software including maximum intensity projection (MIP), shaded surface display (SSD), and volume rendering technique (VRT). Results: The blood vessels were successfully demonstrated in 71 cases out of 73. Abnormality was found in 63 cases out of 71. The intracranial CTA showed aneurysm in 7 cases, arteriovenous malformation in 5, carotid-cavernous fistula in 2, cerebral vascular occlusion in 2, astrocytoma in 2, and meningioma in 3. The carotid CTA revealed carotid stenosis in 4 cases, vertebral artery stenosis in 2 and a post-bracket implantation subclavian artery. In pulmonary artery CTA, pulmonary artery embolism and 5 cases of pulmonary artery involved with lung cancer were seen in 3 cases. In coronary artery CTA, coronary artery stenosis were shown in 3 cases. The aortic CTA demonstrated aortic dissection in 4, aortic stenosis calcification in 5, aortic aneurysm in 2, liver cancer in 2, renal artery stenosis in 2, and Budd-Chiari syndrome in 2. CTA of low extremity artery revealed external iliac artery occlusion in 2 and femoral artery stenosis in 5. Conclusion: By combining axial images with various reconstructed with adjacent organs can also be evaluated. MSCTA is of convenience, reliability, safety and noninvasive. (authors)

  6. Optimization of scanning parameters for multi-slice CT colonography: Experiments with synthetic and animal phantoms

    AIM: To determine the optimal collimation, pitch, tube current and reconstruction interval for multi-slice computed tomography (CT) colonography with regard to attaining satisfactory image quality while minimizing patient radiation dose. MATERIALS AND METHODS: Multi-slice CT was performed on plastic, excised pig colon and whole pig phantoms to determine optimal settings. Performance was judged by detection of simulated polyps and statistical measures of the image parameters. Fat and muscle conspicuity was measured from images of dual tube-current prone/supine patient data to derive a measure of tube current effects on tissue contrast. RESULTS: A collimation of 4x2.5 mm was sufficient for detection of polyps 4 mm and larger, provided that a reconstruction interval of 1.25 mm was used. A pitch of 1.5 allowed faster scanning and reduced radiation dose without resulting in a loss of important information, i.e. detection of small polyps, when compared with a pitch of 0.75. Tube current and proportional radiation dose could be lowered substantially without deleterious effects on the detection of the air-mucosal interface, however, increased image noise substantially reduced conspicuity of different tissues. CONCLUSION: An optimal image acquisition set-up of 4x2.5 mm collimation, reconstruction interval of 1.25 mm, pitch of 1.5 and dual prone/supine scan of 40/100 mA tube current is proposed for our institution for scanning symptomatic patients. Indications are that where CT colonography is used for colonic polyp screening in non-symptomatic patients, a 40 mA tube current could prove satisfactory for both scans

  7. Optimization of scanning parameters for multi-slice CT colonography: Experiments with synthetic and animal phantoms

    Embleton, K.V. E-mail: k.embleton@man.ac.uk; Nicholson, D.A.; Hufton, A.P.; Jackson, A

    2003-12-01

    AIM: To determine the optimal collimation, pitch, tube current and reconstruction interval for multi-slice computed tomography (CT) colonography with regard to attaining satisfactory image quality while minimizing patient radiation dose. MATERIALS AND METHODS: Multi-slice CT was performed on plastic, excised pig colon and whole pig phantoms to determine optimal settings. Performance was judged by detection of simulated polyps and statistical measures of the image parameters. Fat and muscle conspicuity was measured from images of dual tube-current prone/supine patient data to derive a measure of tube current effects on tissue contrast. RESULTS: A collimation of 4x2.5 mm was sufficient for detection of polyps 4 mm and larger, provided that a reconstruction interval of 1.25 mm was used. A pitch of 1.5 allowed faster scanning and reduced radiation dose without resulting in a loss of important information, i.e. detection of small polyps, when compared with a pitch of 0.75. Tube current and proportional radiation dose could be lowered substantially without deleterious effects on the detection of the air-mucosal interface, however, increased image noise substantially reduced conspicuity of different tissues. CONCLUSION: An optimal image acquisition set-up of 4x2.5 mm collimation, reconstruction interval of 1.25 mm, pitch of 1.5 and dual prone/supine scan of 40/100 mA tube current is proposed for our institution for scanning symptomatic patients. Indications are that where CT colonography is used for colonic polyp screening in non-symptomatic patients, a 40 mA tube current could prove satisfactory for both scans.

  8. Diagnostic performance of 3D TSE MRI versus 2D TSE MRI of the knee at 1.5 T, with prompt arthroscopic correlation, in the detection of meniscal and cruciate ligament tears*

    Chagas-Neto, Francisco Abaeté; Nogueira-Barbosa, Marcello Henrique; Lorenzato, Mário Müller; Salim, Rodrigo; Kfuri-Junior, Maurício; Crema, Michel Daoud

    2016-01-01

    Objective To compare the diagnostic performance of the three-dimensional turbo spin-echo (3D TSE) magnetic resonance imaging (MRI) technique with the performance of the standard two-dimensional turbo spin-echo (2D TSE) protocol at 1.5 T, in the detection of meniscal and ligament tears. Materials and Methods Thirty-eight patients were imaged twice, first with a standard multiplanar 2D TSE MR technique, and then with a 3D TSE technique, both in the same 1.5 T MRI scanner. The patients underwent knee arthroscopy within the first three days after the MRI. Using arthroscopy as the reference standard, we determined the diagnostic performance and agreement. Results For detecting anterior cruciate ligament tears, the 3D TSE and routine 2D TSE techniques showed similar values for sensitivity (93% and 93%, respectively) and specificity (80% and 85%, respectively). For detecting medial meniscal tears, the two techniques also had similar sensitivity (85% and 83%, respectively) and specificity (68% and 71%, respectively). In addition, for detecting lateral meniscal tears, the two techniques had similar sensitivity (58% and 54%, respectively) and specificity (82% and 92%, respectively). There was a substantial to almost perfect intraobserver and interobserver agreement when comparing the readings for both techniques. Conclusion The 3D TSE technique has a diagnostic performance similar to that of the routine 2D TSE protocol for detecting meniscal and anterior cruciate ligament tears at 1.5 T, with the advantage of faster acquisition. PMID:27141127

  9. Virtual colonoscopy with multi-slice computed tomography; Virtuelle Koloskopie mit der Mehrschichtcomputertomographie. Vorlaeufige Ergebnisse

    Rust, G.-F.; Eisele, O.; Reiser, M. [Institut fuer Klinische Radiologie, Klinikum Grosshadern, Muenchen Univ. (Germany); Hoffmann, J.N.; Kopp, R.; Fuerst, H. [Chirurgische Klinik und Poliklinik, Klinikum der Univ. Muenchen (Germany)

    2000-03-01

    Subject: Using multi-slice computed tomography (MSCT) large body areas can scanned with high spatial resolution. In this study, MSCT was employed for virtual colonoscopy in various pathologies of the colon. Results: Nine polyps and four of five colon carcinomas were detected using MSCT virtual colonoscopy. In three patients with ulcerative colitis virtual coloscopy revealed morphological alterations compatible with this disease. In two of four patients with multiple diverticula of the colon the true extent of the disorder could be assessed in virtual colonoscopy. (orig.) [German] Fragestellung: Die Mehrschichtcomputertomographie (MSCT) vermag, grosse Organbereiche mit hoher raeumlicher Aufloesung zu untersuchen. Daher koennen auch fuer die virtuelle Koloskopie eine bisher nicht erreichbare Ortsaufloesung und Detailtreue erwartet werden. Die ersten Ergebnisse mit der MSCT-Koloskopie bei unterschiedlichen pathologischen Veraenderungen des Kolons werden vorgestellt. Ergebnisse: 4 von 5 Kolonkarzinomen konnten mit der virtuellen Koloskopie dargestellt werden. Bei 3 Patienten wurden mit der virtuellen Koloskopie typische Veraenderungen der Colitis ulcerosa dargestellt, wovon ein Patient die konventionelle Koloskopie nicht tolerierte. Bei 9 Patienten mit Kolonpolypen stimmten die virtuelle und konventionelle Koloksopie vollstaendig ueberein. Bei 4 Patienten mit Divertikulose war mit der virtuellen Koloskopie nur in 2 Faellen der Befund vollstaendig zu sichern. (orig.)

  10. Value of multi-slice spiral CT MPVR reconstruction in the diagnosis of acute appendicitis

    Objective: To investigate the value of multi-slice spiral CT MPVR reconstruction in the diagnosis of acute appendicitis. Methods: A total of 39 patients with clinically suspected acute appendicitis underwent surgery from February, 2002 to September, 2003. They were prospectively examined before surgery with routine CT scanning and MPVR reconstruction spiral CT. 31 cases of appendicitis were confirmed after appendectomy. CT scans and surgery-pathology reports were evaluated on a five-grade scale from hyperemic-edematous appendix to abscess (normal appendix: 0 grade). Results: The results of spiral CT MPVR reconstruction were compared with the surgical and pathologic findings at appendectomy, yielding an accuracy of 87.2%, sensitivity of 90.3%, specificity of 75%, positive predictive value of 93.3%, and negative predictive value of 66.7%, respectively. Results of routine CT yielded an accuracy of 38.5%, sensitivity of 38.7%, specificity of 37.5%, positive predictive value of 70.6%, and negative predictive value of 13.6%, respectively. MPVR reconstruction signs of 28 patients with acute appendicitis included enlarged appendix ( > 6 mm) (96.4%), appendicoliths (26.7%), caecal apical thickening (36.7%), periappendiceal inflammation (71.4%), and abscess (10.7%). Conclusion: The use of spiral CT MPVR reconstruction in patients with equivocal clinical presentation suspected of having acute appendicitis can lead to a significant improvement in the preoperative diagnosis and maybe a decrease in surgical-pathologic severity of appendiceal disease. (authors)

  11. Myocardial bridges and mural coronary artery: identification with multi-slice CT versus coronary angiography

    Objective: To compare the feasibility of multi-slices computed tomography (MSCT) versus coronary angiography(CAG) for identification of myocardial bridges and mural coronary artery(MB-MCA). Methods: For 76 patients suspecting coronary heart disease the MSCT and CAG were performed for the coronary imaging. The MB-MCAs were identified on the CT images and angiograms by radiologists and cardiologists separately and independently before and after consulting each other. The data was statistically analyzed using χ2-squrae test. Results: Before consulting each other, 29 MB-MCA in 27 patients and 2 MB-MCA in two cases were detected using MSCT and CAG by radiologists and cardiologist separately and independently with significant difference statistically (χ2 = 10.52, P2=28.82, P2=10.52, P2=-0.33, P<0.05). Conclusion: MSCT is outperformed the CAG in detecting of MB-MCA and the coronary tortuosity on angiograms can be of the suggesting to existing of MB-MCA. (authors)

  12. Multi-slice CT evaluation of glenoid bone loss in patients with recurrent anterior shoulder dislocation

    Objective: To evaluate multi-slice CT (MSCT) in glenoid bone loss of patients with recurrent anterior shoulder dislocation. Methods: MSCT findings of 108 patients with recurrent anterior shoulder dislocation and 12 with single anterior shoulder dislocation were retrospectively studied. The incidence, degrees and locations of glenoid bone losses were recorded. The incidence was analyzed with Fisher exact test. The maximum length,depth and proportion were compared with Wilcoxon rank sum test. Results: Glenoid bone loss was detected in 91.7% (99/108) patients with recurrent anterior shoulder dislocation. The proportion of glenoid bone loss was (16.0 ± 6.0)%, and the central locations of glenoid bone loss were from 2: 20 to 4: 25 (mean 3: 20). Sixty-two percent (67/108) patients had bony Bankart lesions in which 58.2% (39/67) bony fragments were free and 41.8% (28/67) were adherent to the anterior border of the glenoid cavity. Seventy-five percent (9/12) patients with single shoulder dislocation had anterior glenoid bone loss,and the proportion of glenoid bone loss was (15.2 ± 7.1)%. There were no statistical differences of the incidence (P=0.100) and proportion of glenoid bone loss (P=0.453) between the recurrent and single anterior shoulder dislocation. Conclusions: Anterior glenoid bone loss is common in patients with recurrent anterior shoulder dislocation. (authors)

  13. Multi-slice CT angiography by triple-phase enhancement in preoperative evaluation of hepatocellular carcinoma

    XIAO Xi-gang; HAN Xue; SHAN Wei-dong; LI An-yuan

    2005-01-01

    Background Triple-phase enhancement of multi-slice computed tomography (MSCT) has markedly improved the diagnostic accuracy of hepatocellular carcinoma (HCC), and MSCT angiography (MSCTA) has been proved useful in detecting vascular anatomy noninvasively. This study aimed to explore the value of MSCTA by triple-phase enhancement in preoperative evaluation of HCC.Methods Fifty-six consecutive cases of primary HCC scheduled for resection were studied with MSCTA by triple-phase enhancement. The raw data images were processed on a workstation for multiplanar reconstruction (MPR) and three-dimensional (3D) reconstruction. The findings after processing of the data were compared with those after surgery or intraoperative sonography. Results The false positive rate of MSCTA by triple-phase enhancement was 10.1% and its false negative rate was 4.3% in detecting HCC. No significant difference was observed in MSCTA and surgery or intraoperative sonography in detecting vascular anatomy anomalies and pathologic variations, whereas significant difference was found in detecting bile duct invasion with MSCT compared to intraoperative sonography.Conclusions MSCTA by triple-phase enhancement not only improves the detection of HCC, but also provides valuable preoperative information about hepatic vascular architecture and parenchyma. MSCTA by triple-phase enhancement is worthy of application as a non-invasive method in preoperative evaluation of HCC.

  14. Multi-slice spiral CT appearances of pulmonary infections after liver transplantation

    Objective: To investigate multi-slice spiral CT (MSCT) appearances of pulmonary infections after liver transplantation (LT) and the diagnostic values of MSCT. Methods: The clinical data and CT images of liver transplantation receptors were reviewed from 2001 August to 2007 June, the types, onset time and CT appearances of pulmonary infections were analyzed retrospectively. Chi square test was used for the statistics. Results: The incidence rate of pulmonary infections after LT was 32.9% (174/529), the mortality was 9.8% (17/174), The incidence of bacterial infection, fungus or associated fungus infection, and virus or associated virus infection were 17.2% (n=91), 14.7% (n=78)and 2.3% (n=12)respectively, the pulmonary infections were seen in 64.7%, 28.7% and 6.6% of patients 1 to 30 days, 31-90 days and after 90 days following LT. Consolidations (n=32), ground-glass opacities (n= 22), nodules (n=10), reticular or lineal opacities (n=4) were found in 45 patients who had CT examination, there were no statistic differences in incidence rate between bacterial infection and mycotic infection (P>0.05). Conclusion: Pulmonary bacterial and fungus infection are common after LT, and often present as the mixed infection, the high risk period for infection is within 30 days after LT, thoracic CT scan is very important for characterizing the pulmonary infections after LT. (authors)

  15. Establishment of multi-slice computed tomography (MSCT) reference level in Johor, Malaysia

    Karim, M. K. A.; Hashim, S.; Bakar, K. A.; Muhammad, H.; Sabarudin, A.; Ang, W. C.; Bahruddin, N. A.

    2016-03-01

    Radiation doses from computed tomography (CT) are the highest and most hazardous compared to other imaging modalities. This study aimed to evaluate radiation dose in Johor, Malaysia to patients during computed tomography examinations of the brain, chest and abdomen and to establish the local diagnostic reference levels (DRLs) as are present with the current, state- of-art, multi-slice CT scanners. Survey forms were sent to five centres performing CT to obtain data regarding acquisition parameters as well as the dose information from CT consoles. CT- EXPO (Version 2.3.1, Germany) was used to validate the dose information. The proposed DRLs were indicated by rounding the third quartiles of whole dose distributions where mean values of CTDIw (mGy), CTDIvol (mGy) and DLP (mGy.cm) were comparable with other reference levels; 63, 63, and 1015 respectively for CT Brain; 15, 14, and 450 respectively for CT thorax and 16, 17, and 590 respectively for CT abdomen. The study revealed that the CT practice and dose output were revolutionised, and must keep up with the pace of introductory technology. We suggest that CTDIvol should be included in current national DRLs, as modern CTs are configured with a higher number of detectors and are independent of pitch factors.

  16. Visualisation of animal anatomy using MRI and CT

    Lauridsen, Henrik; Hansen, Kasper; Pedersen, Michael;

    Several traditional handbooks and web-based databases exist with descriptions of animal anatomy, providing dissection photographies or hand drawn images in explanatory figures. In recent years sophisticated databases have been developed providing unique 2D and 3D visualisations of the internal an...... digital models of animal soft and hard tissue anatomy in quality similar or superior to time consuming dissection, and we propose MRI and CT as valuable tools in future studies of animal anatomy in research and education.......Several traditional handbooks and web-based databases exist with descriptions of animal anatomy, providing dissection photographies or hand drawn images in explanatory figures. In recent years sophisticated databases have been developed providing unique 2D and 3D visualisations of the internal and...... imaging (MRI) and CT. Various species (tarantula, horseshoe crab, carp, haddock, lungfish, axolotl) were subjected to multi-slice MRI and CT protocols to produce 2D images of body slices, followed by volume rendering producing 3D digital models of animal anatomy with applications for visualising specific...

  17. Genetic association of glutathione peroxidase-1 with coronary artery calcification in type 2 diabetes: a case control study with multi-slice computed tomography

    Fujimoto Kei

    2007-09-01

    Full Text Available Abstract Background Although oxidative stress by accumulation of reactive oxygen species (ROS in diabetes has become evident, it remains unclear what genes, involved in redox balance, would determine susceptibility for development of atherosclerosis in diabetes. This study evaluated the effect of genetic polymorphism of enzymes producing or responsible for reducing ROS on coronary artery calcification in type 2 diabetes (T2D. Methods An index for coronary-arteriosclerosis, coronary artery calcium score (CACS was evaluated in 91 T2D patients using a multi-slice computed tomography. Patients were genotyped for ROS-scavenging enzymes, Glutathione peroxidase-1 (GPx-1, Catalase, Mn-SOD, Cu/Zn-SOD, as well as SNPs of NADPH oxidase as ROS-promoting elements, genes related to onset of T2D (CAPN10, ADRB3, PPAR gamma, FATP4. Age, blood pressure, BMI, HbA1c, lipid and duration of diabetes were evaluated for a multivariate regression analysis. Results CACS with Pro/Leu genotype of the GPx-1 gene was significantly higher than in those with Pro/Pro (744 ± 1,291 vs. 245 ± 399, respectively, p = 0.006. In addition, genotype frequency of Pro/Leu in those with CACS ≥ 1000 was significantly higher than in those with CACS OR = 3.61, CI = 0.97–13.42; p = 0.045 when tested for deviation from Hardy-Weinberg's equilibrium. Multivariate regression analyses revealed that CACS significantly correlated with GPx-1 genotypes and age. Conclusion The presence of Pro197Leu substitution of the GPx-1 gene may play a crucial role in determining genetic susceptibility to coronary-arteriosclerosis in T2D. The mechanism may be associated with a decreased ability to scavenge ROS with the variant GPx-1.

  18. The comparative study between multi-slice spiral CT angiography and color flow ultrasonography in hepatic and splenic trauma

    Objective: To investigate the clinical value of multi-slice spiral CT angiography and color flow ultra- sonography in hepatic and splenic trauma. Methods Thirty-six cases of hepatic and splenic trauma were collected, the MSCT were analyzed and compared with that of color flow ultrasonography. Results: Seventeen cases were Hepatic trauma including nine cases of hepatic contusion, six cases of sub-envelope hematoma, two cases of both sub-envelope hematoma and hepatic contusion. Nineteen cases were splenic trauma including nine cases of splenic contusion, ten cases of sub-envelope hematoma. Conclusion: Multi-slice spiral CT angiography show hepatic and splenic trauma clearer than that of color flow ultrasonography, and can provide reliable basis for clinic diagnosis and therapy. (authors)

  19. The application of multi-slice CT and image post processing techniques in diagnosing of pulmonary embolism

    Objective: To characterize the pulmonary embolism (PE) on multi-slice CT pulmonary angiography, and to evaluate the role of multi-slice CT pulmonary angiography (CTPA) in the diagnosis of PE. Methods: Forty-five patients with PE confirmed by CTPA were retrospective analyzed. Images were reconstructed with maximal intensity projection (MIP), multiple planar reconstruction (MPR) and volume rendering technique (VRT). The display of pulmonary arteries and the ability of detecting embolisms were compared among the three different reconstruction techniques. Results: MPR images showed superiority to MIP and VRT images in displaying embolisms (P<0.05). Conclusion: MPR images were better than those of MIP and VRT, but provided poor three-dimensional information; MIP and VRT were more straightforward than MPR in displaying large branches of pulmonary artery. MPR combined with MIP and VRT could help to accurately establish PE diagnosis. (author)

  20. Correction of misaligned slices in multi-slice cardiovascular magnetic resonance using slice-to-volume registration

    Hawkes David J; Schnabel Julia A; Netsch Thomas; Pinder Richard J; Chandler Adam G; Hill Derek LG; Razavi Reza

    2008-01-01

    Abstract A popular technique to reduce respiratory motion for cardiovascular magnetic resonance is to perform a multi-slice acquisition in which a patient holds their breath multiple times during the scan. The feasibility of rigid slice-to-volume registration to correct for misalignments of slice stacks in such images due to differing breath-hold positions is explored. Experimental results indicate that slice-to-volume registration can compensate for the typical misalignments expected. Correc...

  1. The Correlation Between Age and Bleeding Volume in Haemorrhagic Stroke Using Multi Slice CT at District Hospitals in Jakarta

    Saefudin, Tatan; Apriantoro, Nursama Heru; Hidayat, Ekaputra Syarif; Purnamawati, Schandra

    2015-01-01

    Haemorrhagic Stroke is a common disease in Indonesia. The best imaging modality for this disease is Multi Slice Computed Tomography Scanning (MSCT), as it may help strengthening the diagnosis as well as determining the brain bleeding volume. This study aimed to show correlation between bleeding volume of the brain and patient’s age using cross-sectional approach. The 68 samples in this study were taken from secondary data from Head CT Scan of Haemorrhagic Stroke cases. Brain bleeding volume i...

  2. Data-driven optimization and evaluation of 2D EPI and 3D PRESTO for BOLD fMRI at 7 Tesla: I. Focal coverage.

    Barry, Robert L; Strother, Stephen C; Gatenby, J Christopher; Gore, John C

    2011-04-01

    Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is commonly performed using 2D single-shot echo-planar imaging (EPI). However, single-shot EPI at 7 Tesla (T) often suffers from significant geometric distortions (due to low bandwidth (BW) in the phase-encode (PE) direction) and amplified physiological noise. Recent studies have suggested that 3D multi-shot sequences such as PRESTO may offer comparable BOLD contrast-to-noise ratio with increased volume coverage and decreased geometric distortions. Thus, a four-way group-level comparison was performed between 2D and 3D acquisition sequences at two in-plane resolutions. The quality of fMRI data was evaluated via metrics of prediction and reproducibility using NPAIRS (Non-parametric Prediction, Activation, Influence and Reproducibility re-Sampling). Group activation maps were optimized for each acquisition strategy by selecting the number of principal components that jointly maximized prediction and reproducibility, and showed good agreement in sensitivity and specificity for positive BOLD changes. High-resolution EPI exhibited the highest z-scores of the four acquisition sequences; however, it suffered from the lowest BW in the PE direction (resulting in the worst geometric distortions) and limited spatial coverage, and also caused some subject discomfort through peripheral nerve stimulation (PNS). In comparison, PRESTO also had high z-scores (higher than EPI for a matched in-plane resolution), the highest BW in the PE direction (producing images with superior geometric fidelity), the potential for whole-brain coverage, and no reported PNS. This study provides evidence to support the use of 3D multi-shot acquisition sequences in lieu of single-shot EPI for ultra high field BOLD fMRI at 7T. PMID:21232613

  3. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT)

    Aims: To compare image quality and visibility of anatomical structures in the mandible between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: One dry mandible was scanned with five CBCT scanners (Accuitomo 3D, i-CAT, NewTom 3G, Galileos, Scanora 3D) and one MSCT system (Somatom Sensation 16) using 13 different scan protocols. Visibility of 11 anatomical structures and overall image noise were compared between CBCT and MSCT. Five independent observers reviewed the CBCT and the MSCT images in the three orthographic planes (axial, sagittal and coronal) and assessed image quality on a five-point scale. Results: Significant differences were found in the visibility of the different anatomical structures and image noise level between MSCT and CBCT and among the five CBCT systems (p = 0.0001). Delicate structures such as trabecular bone and periodontal ligament were significantly less visible and more variable among the systems in comparison with other anatomical structures (p = 0.0001). Visibility of relatively large structures such as mandibular canal and mental foramen was satisfactory for all devices. The Accuitomo system was superior to MSCT and all other CBCT systems in depicting anatomical structures while MSCT was superior to all other CBCT systems in terms of reduced image noise. Conclusions: CBCT image quality is comparable or even superior to MSCT even though some variability exists among the different CBCT systems in depicting delicate structures. Considering the low radiation dose and high-resolution imaging, CBCT could be beneficial for dentomaxillofacial radiology.

  4. Multi-slice spiral CT perfusion imaging of chronic obstructive pulmonary disease

    Objective: To evaluate the diagnostic value of multi-slice spiral CT (MSCT) perfusion imaging in chronic obstructive pulmonary disease (COPD). Methods: Twenty COPD patients and 20 volunteers underwent 8-row detector spiral CT (MSCT) perfusion imaging using cine scan mode with 5 mm slice thickness, 0.5 s rotation time and a total scan time of 45 s with 5 s intervals. 60 ml contrast agent (300 nag I/ml) were administered at a rate of 4 ml/s from the forearm superficial vein. The imaging data were transferred to a workstation. A time-density curve and pseudo-color map were generated automatically with GE CT perfusion 3 software, the blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were measured. Results: Time-density curve was flatter and the peak of the curve was obviously lower in COPD patients than the volunteers. The BF, BV, PS in COPD patients was (24.77±11.49) ml·min-1·100 g-1, (2.48±1.02) ml/100 g and (2.75±1.13) ml· min-1·100 g-1 respectively. In volunteers was (290.14±107.59) ml·min-1·100 g-1, (16.51 ± 5.98) ml/100 g, (8.80±3.03) ml·min-1·100 g-1 respectively. The MTT in COPD patients and volunteers was (10.58±4.85) s and (4.50±1.71)s respectively. The BF, BV and PS in COPD patients was lower than the volunteers, the MTY was higher (P<0.01). Conclusion: MSCT perfusion imaging is helpful for the diagnosis of COPD. (authors)

  5. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT)

    Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Corpas, Livia, E-mail: LiviaCorpas@gmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Souza, Paulo Couto, E-mail: Paulo.CoutoSouza@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Martens, Wendy, E-mail: wendy.martens@uhasselt.b [Department of Basic Medical Sciences, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Shahbazian, Maryam, E-mail: Maryam.Shahbazian@student.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Alonso, Arie, E-mail: ariel.alonso@uhasselt.b [Department of Biostatistics and Statistical Bioinformatics, Universiteit Hasselt (Belgium)

    2010-08-15

    Aims: To compare image quality and visibility of anatomical structures in the mandible between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: One dry mandible was scanned with five CBCT scanners (Accuitomo 3D, i-CAT, NewTom 3G, Galileos, Scanora 3D) and one MSCT system (Somatom Sensation 16) using 13 different scan protocols. Visibility of 11 anatomical structures and overall image noise were compared between CBCT and MSCT. Five independent observers reviewed the CBCT and the MSCT images in the three orthographic planes (axial, sagittal and coronal) and assessed image quality on a five-point scale. Results: Significant differences were found in the visibility of the different anatomical structures and image noise level between MSCT and CBCT and among the five CBCT systems (p = 0.0001). Delicate structures such as trabecular bone and periodontal ligament were significantly less visible and more variable among the systems in comparison with other anatomical structures (p = 0.0001). Visibility of relatively large structures such as mandibular canal and mental foramen was satisfactory for all devices. The Accuitomo system was superior to MSCT and all other CBCT systems in depicting anatomical structures while MSCT was superior to all other CBCT systems in terms of reduced image noise. Conclusions: CBCT image quality is comparable or even superior to MSCT even though some variability exists among the different CBCT systems in depicting delicate structures. Considering the low radiation dose and high-resolution imaging, CBCT could be beneficial for dentomaxillofacial radiology.

  6. Multi-slice CT for visualization of pulmonary embolism using perfusion weighted color maps

    Purpose: The purpose of our preliminary study was to evaluate the feasibility of a new technique for the perfusion weighted color display of the density of lung parenchyma derived from multi-slice CT (MSCT) data sets of clinical routine examinations for visualization of pulmonary embolism (PE). Materials and Methods: Imaging of patients with suspected PE was performed on a commercially available MSCT (Somatom Volume Zoom; Siemens, Forchheim, Germany) after intravenous application of 120 cc of contrast-medium using a power injector. Scan parameters were 140 kV and 100 mAs, using a thin collimation of 4x1 mm and a table speed of 7 mm (pitch: 1.75). Derived from thin collimation axial slices (slice thicknesseff. 1.25 mm, reconstruction increment 0.8 mm), a new image processing technique was deployed. Based on these source images, an automated 3D-segmentation of the lungs was performed followed by threshold based extraction of major airways and vascular structures. The filtered volume data were color encordes and finally overlayed onto the original CT images. This color encoded display of parenchymal density distribution of the lungs was shown in axial, coronal and sagittal plans orientation. In four patients with excluded PE as well as in two patients with proven PE this new technique was performed. Results: In the four patients that were considered negative regarding PE on MSCT, lung densitometry showed a homogeneous distribution of color encoded densities without circumscribed decreased or increased areas, beside the usually present gravity-dependent gradient in ventro-dorsal direction. In the two patients with proven PE, low density values on perfusion weighted color maps were found distally to the occluded pulmonary arteries. (orig.)

  7. Virtual endoscopy of the middle ear: experimental and clinical results of a standardised approach using multi-slice helical computed tomography

    Virtual endoscopy (VE) enables non-invasive 3D endoluminal imaging of the middle ear by post-processing of CT data. To optimise the clinical application a standardised approach was evaluated in normal and pathologic cases. Data acquisition was performed using multi-slice helical CT in 20 normal patients and 15 patients with malformation or trauma. Virtual endoscopy of the tympanic cavity and 3D images of the ossicles were generated using surface and volume rendering. Qualitative assessment of the representation of anatomical structures was performed in normal patients. In 15 pathological cases the diagnostic benefit was evaluated by comparing the 3D images to the 2D images and intra-operative findings. In all 35 cases 3D imaging was possible using the standardised approach. The ossicular chain as well as the bony and soft tissue structures of the tympanic cavity were visualised in 20 normal patients. In 7 of 8 patients with malformation and 1 of 7 patients with trauma the original diagnosis was changed by 3D imaging. Standardisation and evaluation of the method in normal patients is essential as it enhances the diagnostic reliability. Virtual endoscopy facilitates understanding of the complex anatomy of the middle ear. In cases of suspected malformation and confirmed trauma it is helpful for diagnosis and surgical planning. (orig.)

  8. Quantitative measurement of total cerebral blood flow using 2D phase-contrast MRI and doppler ultrasound

    To compare of quantitative measurement of the total cerebral blood flow using two-dimensional phase-contrast MR imaging and Doppler ultrasound. In 16 volunteers (mean age, 26 years; mean body weight, 66 kg) without abnormal medical histories, two-dimensional phase-contrast MR imaging was performed at the level of the C2-3 inter vertebral disc for flow measurement of the internal carotid arteries and the vertebral arteries. Volume flow measurements using Doppler ultrasound were also performed at the internal carotid arteries 2cm above the carotid bifurcation, and at the vertebral arteries at the level of the upper pole of the thyroid gland. Flows in the four vessels measured by the two methods were compared using Wilcoxon's correlation analysis and the median score. Total cerebral blood flows were calculated by summing these four vessel flows, and mean values for the 16 volunteers were calculated. Cerebral blood flows measured by 2-D phase-contrast MR imaging and Doppler ultrasounds were 233 and 239 ml/min in the right internal carotid artery, 250 and 248 ml/min in the left internal carotid artery, 62 and 56 ml/min in the right vertebral artery, and 83 and 68 ml/min in the left vertebral artery. Correlation coefficients of the blood flows determined by the two methods were 0.48, 0.54, 0.49, and 0.62 in each vessel, while total cerebral blood flows were 628±68 (range, 517 to 779) ml/min and 612±79 (range, 482 to 804)ml/min, respectively. Total cerebral blood flow was easily measured using 2-D phase-contrast MR imaging and Doppler ultrasound, and the two noninvasive methods can therefore be used clinically for the measurement of total cerebral blood flow

  9. Diffusion-weighted MRI of the Prostate: Advantages of Zoomed EPI with Parallel-transmit-accelerated 2D-selective Excitation Imaging

    The purpose of our study was to evaluate the use of 2D-selective, parallel-transmit excitation magnetic resonance imaging (MRI) for diffusion-weighted echo-planar imaging (pTX-EPI) of the prostate, and to compare it to conventional, single-shot EPI (c-EPI). The MRI examinations of 35 patients were evaluated in this prospective study. PTX-EPI was performed with a TX-acceleration factor of 1.7 and a field of view (FOV) of 150 x 90 mm2, whereas c-EPI used a full FOV of 380 x 297 mm2. Two readers evaluated three different aspects of image quality on 5-point Likert scales. To quantify distortion artefacts, maximum diameters and prostate volume were determined for both techniques and compared to T2-weighted imaging. The zoomed pTX-EPI was superior to c-EPI with respect to overall image quality (3.39 ± 0.62 vs 2.45 ± 0.67) and anatomic differentiability (3.29 ± 0.65 vs 2.41 ± 0.65), each with p 0.05). Zoomed pTX-EPI leads to substantial improvements in diffusion-weighted imaging (DWI) of the prostate with respect to different aspects of image quality and severity of artefacts. (orig.)

  10. Application of low dose multi-slice helical CT in orbital trauma patients

    Objective: To investigate the most appropriate low radiation dose in multi-slice CT (MSCT) scans for orbital trauma patients. Methods: Thirty trauma patients with suspected orbital fractures who underwent helical CT scans with a 64-MSCT using regular dose were selected. Noise was artificially introduced to the axial images using an image space noise addition tool to simulate 6 sets of lower dose scans with tube current of 30, 70, 100, 140, 170 and 200 mA, respectively. The lowest tube current with adequate image quality for confident diagnosis was determined based on the evaluation of the overall image quality and fracture detection on images at different dose levels. The determined lowest tube current was then validated using clinical scans. Radiation dose related parameters CTDIvol, DLP, ED were also recorded. Image quality was evaluated according to its low-density resolution, noise and structure clarity and characterized into 5-grades of excellent, good, fair, worse and worst. Rank sum test and χ2 test were used for statistics. Results: In 30 trauma patients with regular dose of 300 mA, there were 30 cases of orbital fracture, 19 cases of intraorbital emphysema, 12 cases of ocular muscle injury and 1 case of intraorbital foreign body. These changes could still be clearly observed and correctly diagnosed when the tube current was reduced to as low as 70 mA. However, the overall image quality was mostly fair. At the simulated dose of 100 mA, the majority of images were characterized as excellent or good, and there was no statistical difference compared with that of regular dose scans (P>0.05). In the clinical evaluation for 20 orbital trauma patients with the reduced tube current of 100 mA, the majority of images were judged to be excellent (9 cases) or good (17 cases) and fair (4 cases). The radiation dose (0.29 mSv) was reduced by 70% compared with that of regular tube current of 300 mA (0.86 mSv). Conclusion: The tube current of MSCT may be used as low as 100

  11. Multi-slice computed tomography for diagnosis of combined thoracoabdominal injury

    Jun Liu; Weidong Yue; Dingyuan Du

    2015-01-01

    Purpose:To investigate the diagnostic value of multi-slice computed tomography (MSCT) for combined thoracoabdominal injury.Methods:A retrospective study was conducted to analyze the clinical data and MSCT images of 68 patients who sustained a combined thoracoabdominal injury associated with diaphragm rupture,and 18 patients without diaphragm rupture.All the patients were admitted and treated in the Chongqing Emergency Medical Center (a level Ⅰ trauma center) between July 2005 and February 2014.There were 71 males and 15 females with a mean age of 39.1 years (range 13-88 years).Among the 86 patients,40 patients suffered a penetrating injury,46 suffered a blunt injury as a result of road traffic accident in 21 cases,fall from a height in 16,and crushing injury in 9.The Mscr images were retrospectively reviewed by two radiologists.The results of CT diagnosis were compared with surgical findings and/or follow-up results.Results:Among the 86 cases,diaphragm discontinuity was found in 29 cases,segmental nonrecognition of the diaphragm in 14,diaphragmatic hernia in 21,collar sign in 14,dependent viscera sign in 18,elevated abdominal organs in 21,bowel wall thickening and/or hematoma in 6,and pneumoperitoneum in 8.CT diagnostic accuracy for diaphragm rupture was 88.4% in the right side and 90.7% in the left side.cT diagnostic accuracy for hemopneumothorax,pulmonary contusion,mediastinal hemorrhage,kidney and adrenal gland injuries was 100%,while for liver,spleen and pancreas injuries was 96.5%,96.5%,94.2% respectively.Conclusion:To reach an early diagnosis of combined thoracoabdominal injury,surgeons and radiologists should be familiar with all kinds of images which might show signs of diaphragm rupture,such as diaphragm discontinuity,segmental nonrecognition of the diaphragm,dangling diaphragm sign,diaphragm herniation,collar sign,dependent viscera sign,and elevated abdominal organs.

  12. The value of multi-slice spiral CT in the preoperative assessment of living renal donor

    Objective: The purpose of this study is to assess the value of multi-slice spiral CT (MSCT) in the preoperative evaluation of living renal donor as a all in one modality. Methods: Thirty-six potential living renal donors underwent the examination using a GE light VCT scanner. Informed consent was obtained from all participants. The plain scan, early arterial phase, late arterial phase and excretory phase scans are performed in the former 25 donors (injection rate 5 rolls, total volume 100 mi, tube tension 120 kV). While in the later 11 donors (2 ml/s 40 ml +4 ml/s 60 ml), the scanning protocol included the plain scan ( 100 kV), vascular phase and excretory phase scans (100 kV). The excretory phase data were used in the reconstruction of CT urography in both groups. All images were reviewed by one radiologist and one urologist, and the findings of MSCT were compared with intraoperative findings for 33 donors, to investigate the utilities of MSCT in assessing renal vascularity, urinary tract and lesions of renal parenchyma. When discrepancies are found between the two reviewers, consensus was obtained via discussion. Au data was statiscally processed with SPSS for Windows. Results: MSCT angiography is in accordance with intraoperative findings in demonstrating the anatomy of renal arteries and renal vein trunk, accesary arteries, early branching of renal artery. The findings from CTA are highly in accordance with the intraoperative findings, which facilitate intraoperative ligation and reduce relevant complications. CTU demonstrates the anatomy of urinary, tract in good agreement with the intraoperative findings. The image quality of 3D vascularity and CTU between the two groups, scored 4.4 ± 1.2 vs 4.2 ± 1.3 and 4.6 ± 0.8 vs 4.4 ± 0.9 respectively, no statistical between-groups difference was found (Z=-0.89, -0.47, P>0.05). Conclusion: MSCT multiphase scanning combined with CTA and CTU play a important role in the evaluation of living renal donor, which

  13. Self-navigation with compressed sensing for 2D translational motion correction in free-breathing coronary MRI: a feasibility study.

    Gabriele Bonanno

    Full Text Available PURPOSE: Respiratory motion correction remains a challenge in coronary magnetic resonance imaging (MRI and current techniques, such as navigator gating, suffer from sub-optimal scan efficiency and ease-of-use. To overcome these limitations, an image-based self-navigation technique is proposed that uses "sub-images" and compressed sensing (CS to obtain translational motion correction in 2D. The method was preliminarily implemented as a 2D technique and tested for feasibility for targeted coronary imaging. METHODS: During a 2D segmented radial k-space data acquisition, heavily undersampled sub-images were reconstructed from the readouts collected during each cardiac cycle. These sub-images may then be used for respiratory self-navigation. Alternatively, a CS reconstruction may be used to create these sub-images, so as to partially compensate for the heavy undersampling. Both approaches were quantitatively assessed using simulations and in vivo studies, and the resulting self-navigation strategies were then compared to conventional navigator gating. RESULTS: Sub-images reconstructed using CS showed a lower artifact level than sub-images reconstructed without CS. As a result, the final image quality was significantly better when using CS-assisted self-navigation as opposed to the non-CS approach. Moreover, while both self-navigation techniques led to a 69% scan time reduction (as compared to navigator gating, there was no significant difference in image quality between the CS-assisted self-navigation technique and conventional navigator gating, despite the significant decrease in scan time. CONCLUSIONS: CS-assisted self-navigation using 2D translational motion correction demonstrated feasibility of producing coronary MRA data with image quality comparable to that obtained with conventional navigator gating, and does so without the use of additional acquisitions or motion modeling, while still allowing for 100% scan efficiency and an improved ease

  14. Multi-slice and dual-source CT in cardiac imaging. Principles - protocols - indications - outlook. 2. ed.

    Ohnesorge, B.M. [Siemens Medical Solutions Group China, Beijing (China); Flohr, T.G. [Siemens Medical Solutions, Forchheim (Germany). Div. CT Physics and Applications Development; Becker, C.R.; Reiser, M.F. [Muenchen Univ. Klinikum Grosshadern (Germany). Dept. of Clinical Radiology; Knez, A [Muenchen Univ. Klinikum Grosshadern (Germany). Section Head Imaging

    2007-07-01

    Cardiac diseases, and in particular coronary artery disease, are the leading cause of death and morbidity in industrialized countries. The development of non-invasive imaging techniques for the heart and the coronary arteries has been considered a key element in improving patient care. A breakthrough in cardiac imaging using CT occurred in 1998, with the introduction of multi-slice computed tomography (CT). Since then, amazing advances in performance have taken place with scanners that acquire up to 64 slices per rotation. This book discusses the state-of-the-art developments in multi-slice CT for cardiac imaging as well as those that can be anticipated in the future. It serves as a comprehensive work that covers all aspects of this technology, from the technical fundamentals and image evaluation all the way to clinical indications and protocol recommendations. This fully reworked second edition draws on the most recent clinical experience obtained with 16- and 64-slice CT scanners by world-leading experts from Europe and the United States. It also includes 'hands-on' experience in the form of 10 representative clinical case studies, which are included on the accompanying CD. As a further highlight, the latest results of the very recently introduced dual-source CT, which may soon represent the CT technology of choice for cardiac applications, are presented. This book will not only convince the reader that multi-slice cardiac CT has arrived in clinical practice, it will also make a significant contribution to the education of radiologists, cardiologists, technologists, and physicists-whether newcomers, experienced users, or researchers. (orig.)

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

    Kühl, J Tobias; Lønborg, Jacob; Fuchs, Andreas;

    2012-01-01

    dynamic LA volume changes. Conversely, cardiac magnetic resonance imaging (CMR) and multi-slice computed tomography (MSCT) appears more appropriate for such measures. We sought to determine the relationship between LA size assessed with TTE and LA size and function assessed with CMR and MSCT. Fifty......Measurement of left atrial (LA) maximal volume (LA(max)) using two-dimensional transthoracic echocardiography (TTE) provides prognostic information in several cardiac diseases. However, the relationship between LA(max) and LA function is poorly understood and TTE is less well suited for measuring...

  16. Multi-slice echo-planar spectroscopic MR imaging provides both global and local metabolite measures in multiple sclerosis

    Mathiesen, Henrik Kahr; Tscherning, Thomas; Sorensen, Per Soelberg;

    2005-01-01

    MR spectroscopy (MRS) provides information about neuronal loss or dysfunction by measuring decreases in N-acetyl aspartate (NAA), a metabolite widely believed to be a marker of neuronal viability. In multiple sclerosis (MS), whole-brain NAA (WBNAA) has been suggested as a marker of disease...... longitudinal studies have often been hampered by standardization and reproducibility problems. Multi-slice echo-planar spectroscopic imaging (EPSI) is presented as a promising alternative to single-voxel or nonlocalized spectroscopy for obtaining global metabolite estimates in MS. In the same session...

  17. Clinical application of multi-slice helical CT volumetric scanning in lumber spine

    Objective: To evaluate the clinical application value of multi-slice helical CT volumetric (VH) scanning in lumber spine. Methods: One thousand of patients with back and leg pain who underwent CT examinations were selected as subjects. We simulated the traditional protocol of single-slice(SS) discrete scanning for L3/4, L4/5, and L5/S1 intervertebral discs. The VH scanning mode was performed with 120 kV, 210 mAs, pitch of 1.5 and coverage of 97.5 mm. The simulated SS scanning mode was performed with 120 kV, 240 mAs and coverage of 45.0 mm. The diagnostic outcomes and the radiation doses were compared between the two scanning modes. Two groups doctors observed ten terms, including the osseous spinal stenosis, narrowed intervertebral space and so on in two scanning modes respectively. Then consistency analysis of the data was carded out. Results: The VH scanning mode showed far more features than the SS mode. The detection rates of the VH mode in the osseous spinal stenosis, narrowed intervertebral space, herniated nucleus pulposus, narrowed lateral recess, vertebral lesion, hypertrophy of L5 transverse process, abnormal direction of facet, facet degeneration, lumbar spondyloschisis, and paraspinal soft tissue were 11.8% (n=118), 38.5% (n=385), 9.3% (n=93), 46.8% (n=468), 31.4% (n=314), 5.7% (n= 57), 25.4% (n=254), 49.7% (n=497), 9.9% (n=99), and 0.6% (n=6) respectively, while the detection rates of the SS mode in ten terms were 5.6% (n=56), 0, 0.6% (n=6), 27.9% (n=279), 22.4% (n=224), 1.2% (n=12), 16.7% (n=167), 37.2% (n=372), 0.5% (n=5), and 0.2% (n=2) respectively. The difference between the two groups had statistically significance (average P0.05). The detection rates of the VH mode were higher than the SS mode in the osseous spinal stenosis, narrowed intervertebral space, herniated nucleus pulposus, lumbar spondyloschisis, being 6.2% (n=62), 38.5% (n=385), 8.7% (n=87), and 9.4% (n=94), respectively. In addition, VH mode only partially showed the articular facets

  18. Diffusion-weighted MRI of the Prostate: Advantages of Zoomed EPI with Parallel-transmit-accelerated 2D-selective Excitation Imaging

    Thierfelder, Kolja M.; Scherr, Michael K.; Weiss, Jakob; Mueller-Lisse, Ullrich G.; Theisen, Daniel [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Notohamiprodjo, Mike; Nikolaou, Konstantin [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); University Hospital Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Dietrich, Olaf [Ludwig-Maximilians-University Hospital Munich, Josef Lissner Laboratory for Biomedical Imaging, Institute for Clinical Radiology, Munich (Germany); Pfeuffer, Josef [Siemens Healthcare, Application Development, Erlangen (Germany)

    2014-12-15

    The purpose of our study was to evaluate the use of 2D-selective, parallel-transmit excitation magnetic resonance imaging (MRI) for diffusion-weighted echo-planar imaging (pTX-EPI) of the prostate, and to compare it to conventional, single-shot EPI (c-EPI). The MRI examinations of 35 patients were evaluated in this prospective study. PTX-EPI was performed with a TX-acceleration factor of 1.7 and a field of view (FOV) of 150 x 90 mm{sup 2}, whereas c-EPI used a full FOV of 380 x 297 mm{sup 2}. Two readers evaluated three different aspects of image quality on 5-point Likert scales. To quantify distortion artefacts, maximum diameters and prostate volume were determined for both techniques and compared to T2-weighted imaging. The zoomed pTX-EPI was superior to c-EPI with respect to overall image quality (3.39 ± 0.62 vs 2.45 ± 0.67) and anatomic differentiability (3.29 ± 0.65 vs 2.41 ± 0.65), each with p < 0.0001. Artefacts were significantly less severe in pTX-EPI (0.93 ± 0.73 vs 1.49 ± 1.08), p < 0.001. The quantitative analysis yielded a higher agreement of pTX-EPI with T2-weighted imaging than c-EPI with respect to coronal (ICCs: 0.95 vs 0.93) and sagittal (0.86 vs 0.73) diameters as well as prostate volume (0.94 vs 0.92). Apparent diffusion coefficient (ADC) values did not differ significantly between the two techniques (p > 0.05). Zoomed pTX-EPI leads to substantial improvements in diffusion-weighted imaging (DWI) of the prostate with respect to different aspects of image quality and severity of artefacts. (orig.)

  19. The relationship between the appearances of colorectal tumor in multi-slices spiral CT and the pathologic histology

    Objective: To evaluate the relationship between the appearances of colorectal tumor in multi-slices spiral-CT and the pathologic histology. Methods: 92 patients with colorectal tumor, who had undergone preoperative MSCT examination, were reviewed retrospectively. The detail information of their appearances in multi-slices spiral CT, the pathologic histology, lymph node metastasis and pericolonic infiltration were analyzed. All the patients were cleaned intestine tracts and were given an enema (2.5% iso-osmia mannitol solution) before undergoing plain scan and portal venous phase enhanced scan with 64-slices spiral-CT Patients were classified into five types according to pathology: well-differentiated, moderately differentiated, poorly differentiated adencarcinoma, mucinous adenocarcinoma and signet-ring cell carcinoma. And then each group's CT features in plain and enhanced scan, lymph node metastasis, remote metastasis and infiltration were analyzed. Eventually, they were categorized into three groups based on their pathology of statistics. The first group was the poorly differentiated adencarcinoma, the second mucinous adenocarcinoma and signet-ring cell carcinoma, and the third well-differentiated and moderately differentiated adenocarcinoma. Results Of all these cases, 74 cases were of moderately differentiated adencarcinoma, and 4 cases of well differentiated adencarcinoma, 6 cases of poorly differentiated adencarcinoma, 7 cases of mucinous adenocarcinoma, only 1 case was of signet-ring cell carcinoma In first group, the average CT value in plain scanning was 41.00±6.39Hu, and 74.83±9.48Hu after contrast enhancement. In second group, the CT value was 39.00±3.46Hu and 73.66±11.66Hu respectively. In third group, the CT value was 44.83±5.95Hu and 85.05±10.47Hu respectively. Statistically significant difference existed comparing the first group with those of the other two groups (p<0.05). Each group's ratio of lymph node metastasis was 50% in first group, 37

  20. Multi-slice to volume registration of ultrasound data to a statistical atlas of human pelvis

    Ghanavati, Sahar; Mousavi, Parvin; Fichtinger, Gabor; Foroughi, Pezhman; Abolmaesumi, Purang

    2010-02-01

    Identifying the proper orientation of the pelvis is a critical step in accurate placement of the femur prosthesis in the acetabulum in Total Hip Replacement (THR) surgeries. The general approach to localize the orientation of the pelvis coordinate system is to use X-ray fluoroscopy to guide the procedure. An alternative can be employing intra-operative ultrasound (US) imaging with pre-operative CT scan or fluoroscopy imaging. In this paper, we propose to replace the need of pre-operative imaging by using a statistical shape model of the pelvis, constructed from several CT images. We then propose an automatic deformable intensity-based registration of the anatomical atlas to a sparse set of 2D ultrasound images of the pelvis in order to localize its anatomical coordinate system. In this registration technique, we first extract a set of 2D slices from a single instance of the pelvic atlas. Each individual 2D slice is generated based on the location of a corresponding 2D ultrasound image. Next, we create simulated ultrasound images out of the 2D atlas slices and calculate a similarity metric between the simulated images and the actual ultrasound images. The similarity metric guides an optimizer to generate an instance of the atlas that best matches the ultrasound data. We demonstrated the feasibility of our proposed approach on two male human cadaver data. The registration was able to localize a patient-specific pelvic coordinate system with origin translation error of 2 mm and 3.45 mm, and average axes rotation error of 3.5 degrees and 3.9 degrees for the two cadavers, respectively.

  1. Interpolated Compressed Sensing for 2D Multiple Slice Fast MR Imaging

    Yong Pang; Xiaoliang Zhang

    2013-01-01

    Sparse MRI has been introduced to reduce the acquisition time and raw data size by undersampling the k-space data. However, the image quality, particularly the contrast to noise ratio (CNR), decreases with the undersampling rate. In this work, we proposed an interpolated Compressed Sensing (iCS) method to further enhance the imaging speed or reduce data size without significant sacrifice of image quality and CNR for multi-slice two-dimensional sparse MR imaging in humans. This method utilizes...

  2. Multi-slice Computed Tomography Angiography in the Detection of Residual or Recurrent Cerebral Aneurysms after Surgical Clipping

    Purpose: To assess the diagnostic accuracy of multi-slice computed tomography (MSCT) angiography compared to digital subtraction angiography (DSA) in detecting residual or recurrent aneurysms in patients undergoing aneurysm clipping surgery. Material and Methods: Eight patients with nine aneurysms who had both MSCTA and DSA were included in the study. Two independent experienced neuroradiologists evaluated the examinations. Results: Accuracy, sensitivity, and specificity of detecting residual or recurrent aneurysms on MSCTA were 0.80, 0.60, and 1.00, respectively. Positive and negative predictive values were 1.00 and 0.71, respectively. Conclusion: MSCTA is a promising technique for evaluating residual or recurrent aneurysms in patients undergoing surgical treatment of aneurysm with titanium clips

  3. Studies on intracranial collateral circulation with multi-slice CT angiography in patients with symptomatic cerebral artery stenosis

    Shu-qing ZHOU

    2011-06-01

    Full Text Available Objective To explore the features of intracranial collateral circulation in patients with symptomatic cerebral artery stenosis.Method Ninety-four patients with ischemic cerebrovascular disease admitted from Apr.2004 to Jun.2009 were involved in present study.All the patients were examined with cerebral multi-slice CT angiography,and the features of cerebral artery stenosis and intracranial collateral circulation were evaluated using maximum intensity projection(MIP and volume rendering(VR images of CT angiography.Result Of the 94 patients involved,48 were diagnosed as cerebral artery stenosis,including 29 cases of cerebral infarction,18 of transient ischemic attack(TIA and 1 of moyamoya disease(MMD.Among the 14 cases of severe cerebral artery stenosis or occlusion,cerebral infarction was found in 6 cases with lesser intracranial collateral vessels(including massive cerebral infarction in 4 cases and watershed infarction in 2 cases,and focal infarction of central semi-ovale in 1 case and TIA in 7 cases were found with abundant intracranial collateral vessels.Multiple lacunar infarction was found in 22 cases of mild or moderate cerebral artery stenosis,but there was no significant correlation between the stenosed arteries and infarction sites.Abundant intracranial collateral vessels were found in one patient with Moyamoya disease but no infarction was observed.Conclusions Intracranial collateral circulation plays an important role of compensation in patients with severe cerebral artery stenosis or occlusion.Cerebral angiography with multi-slice CT is of great significance in evaluation of cerebral artery stenosis and intracranial collateral circulation.

  4. Qualitative and quantitative assessment of wrist MRI at 3.0T - Comparison between isotropic 3D turbo spin echo and isotropic 3D fast field echo and 2D turbo spin echo

    Jung, Jee Young [Dept. of Radiology, Chungang Univ. Hospital, School of Medicine, Chungang Univ. (Korea, Republic of); Yoon, Young Cheol [Dept. of Radiology, Samsung Medical Center, School of Medicine, Sungkyunkwan Univ. (Korea, Republic of)], e-mail: ycyoon@skku.edu; Jung, Jin Young [Dept. of Radiology, Saint Paul' s Hospital, The Catholic Univ. (Korea, Republic of); Choe, Bong-Keun [Dept. of Preventive Medicine, School of Medicine, Kyung Hee Univ., Seoul (Korea, Republic of)

    2013-04-15

    Background: Isotropic three-dimensional (3D) magnetic resonance imaging (MRI) has been applied to various joints. However, comparison for image quality between isotropic 3D MRI and two-dimensional (2D) turbo spin echo (TSE) sequence of the wrist at a 3T MR system has not been investigated. Purpose: To compare the image quality of isotropic 3D MRI including TSE intermediate-weighted (VISTA) sequence and fast field echo (FFE) sequence with 2D TSE intermediate-weighted sequence of the wrist joint at 3.0 T. Material and Methods: MRI was performed in 10 wrists of 10 healthy volunteers with isotropic 3D sequences (VISTA and FFE) and 2D TSE intermediate-weighted sequences at 3.0 T. The signal-to-noise ratio (SNR) was obtained by imaging phantom and noise-only image. Contrast ratios (CRs) were calculated between fluid and cartilage, triangular fibrocartilage complex (TFCC), and the scapholunate ligament. Two radiologists independently assessed the visibility of TFCC, carpal ligaments, cartilage, tendons and nerves with a four-point grading scale. Statistical analysis to compare CRs (one way ANOVA with a Tukey test) and grades of visibility (Kruskal-Wallis test) between three sequences and those for inter-observer agreement (kappa analysis) were performed. Results: The SNR of 2D TSE (46.26) was higher than those of VISTA (23.34) and 3D FFE (19.41). CRs were superior in 2D TSE than VISTA (P = 0.02) for fluid-cartilage and in 2D TSE than 3D FFE (P < 0.01) for fluid-TFCC. The visibility was best in 2D TSE (P < 0.01) for TFCC and in VISTA (P = 0.01) for scapholunate ligament. The visibility was better in 2D TSE and 3D FFE (P 0.04) for cartilage and in VISTA than 3D FFE (P < 0.01) for TFCC. The inter-observer agreement for the visibility of anatomic structures was moderate or substantial. Conclusion: Image quality of 2D TSE was superior to isotropic 3D MR imaging for cartilage, and TFCC. 3D FFE has better visibility for cartilage than VISTA and VISTA has superior visibility for

  5. 心脏二尖瓣病变的多层螺旋CT诊断%Multi-slice Spiral Computed Tomography in the Diagnosis of Mitral Valve Diseases

    吴丽娜; 鹿强

    2016-01-01

    本文从心脏二尖瓣多层螺旋CT研究方法、正常解剖的螺旋CT表现、二尖瓣血流动力特征及心肌改变、二尖瓣膜病螺旋CT表现四个方面分析了心脏二尖瓣病变螺旋CT的诊断价值,并简要介绍了MDCT/EBCT、MRI与US技术在心脏二尖瓣病变诊断方面的优缺点及展望。%This paper analyzed the clinical value of the multi-slice computed tomography in the diagnosis of heart mitral valve diseases in four aspects: the research method of multi-slice CT in heart mitral valve diseases, the manifestations of multi-slice CT in the normal anatomy, the characteristics of hemodynamics and myocardial changes in mitral valve diseases, and the manifestations of multi-slice CT in mitral valve diseases. The paper also brielfy introduced the pros and cons as well as the development prospect of the application of multi-detector computed tomography/electron-beam computed tomography and magnetic resonance imaging and ultrasonography in the diagnosis of mitral valve diseases.

  6. Role of multi-slice CT coronary angiography in evaluating the different patterns of coronary artery disease in patients with unstable angina

    Gamal Eldine M. Niazi

    2015-09-01

    Conclusion: Non-invasive multi-slice CT coronary angiography is a reliable technique of high ability to detect coronary artery disease and estimate the degree of obstruction, number of affected arteries and the pattern of their affection and can be used in workup in patients with unstable angina.

  7. MRI and 2D-CSI MR spectroscopy of the brain in the evaluation of patients with acute onset of neuropsychiatric systemic lupus erythematosus

    MRI and 2D-CSI spectroscopy were performed in eight patients with systemic lupus erythematosus who presented with acute onset of neuropsychiatric lupus (NP-SLE), and in seven normal controls to evaluate for differences in metabolic peaks and metabolic ratios between the two groups. Also, the interval change of the metabolic peaks and their ratios during treatment in the NP-SLE patient group was evaluated. Metabolic peaks for N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), and lactate/lipids (LL) and their ratios (NAA/Cr, NAA/Cho, Cho/Cr, LL/Cr) were determined at initial presentation and 3 and 6 months later. In the eight lupus patients compared to the seven normal controls, NAA/Cho ratios were lower at presentation (1.05 vs 1.25; p = 0.004) and decreased even further at the three month follow-up (0.92 vs 1.05; p = 0.008). In contrast, both Cho/Cr (1.42 vs 1.26; p = 0.026) and LL/Cr ratios (0.26 vs 0.19; p = 0.002) were higher in the lupus patients at presentation compared to the controls and did not significantly change at three and six months follow-up. The NAA/Cr ratios were lower in the lupus patients compared to the controls at presentation but the difference was not statistically significant. However, the mean NAA/Cr significantly decreased from the initial examination to the three month follow-up (1.42 vs 1.32; p = 0.049) but did not significantly change from the three to the six month follow-up examinations. The NAA/Cr, Cho/Cr, and NAA/Cho ratios varied significantly (p < 0.05, p < 0.05, p < 0.05, respectively) between the 17 different locations measured in the brain in all eight patients and seven controls. Both the NAA/Cr ratios and the Cho/Cr ratios were also significantly lower in the gray matter than in the white matter (p < 0.0001) in both patients and controls, whereas the LL/Cr and NAA/Cho ratios were not significantly different. In conclusion, 2D-CSI MR spectroscopy may be useful in the early detection of metabolic CNS changes in NP

  8. MRI and 2D-CSI MR spectroscopy of the brain in the evaluation of patients with acute onset of neuropsychiatric systemic lupus erythematosus

    Sundgren, P.C.; Jennings, J.; Gebarski, S.; Pang, Y.; Maly, P. [University of Michigan Health Systems, Department of Radiology, Ann Arbor, MI (United States); Attwood, J.T.; McCune, W.J. [University of Michigan Health Systems, Department of and Rheumatology, Ann Arbor, MI (United States); Nan, B. [University of Michigan Health Systems, School of Public Health, Ann Arbor, MI (United States)

    2005-08-01

    MRI and 2D-CSI spectroscopy were performed in eight patients with systemic lupus erythematosus who presented with acute onset of neuropsychiatric lupus (NP-SLE), and in seven normal controls to evaluate for differences in metabolic peaks and metabolic ratios between the two groups. Also, the interval change of the metabolic peaks and their ratios during treatment in the NP-SLE patient group was evaluated. Metabolic peaks for N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), and lactate/lipids (LL) and their ratios (NAA/Cr, NAA/Cho, Cho/Cr, LL/Cr) were determined at initial presentation and 3 and 6 months later. In the eight lupus patients compared to the seven normal controls, NAA/Cho ratios were lower at presentation (1.05 vs 1.25; p = 0.004) and decreased even further at the three month follow-up (0.92 vs 1.05; p = 0.008). In contrast, both Cho/Cr (1.42 vs 1.26; p = 0.026) and LL/Cr ratios (0.26 vs 0.19; p = 0.002) were higher in the lupus patients at presentation compared to the controls and did not significantly change at three and six months follow-up. The NAA/Cr ratios were lower in the lupus patients compared to the controls at presentation but the difference was not statistically significant. However, the mean NAA/Cr significantly decreased from the initial examination to the three month follow-up (1.42 vs 1.32; p = 0.049) but did not significantly change from the three to the six month follow-up examinations. The NAA/Cr, Cho/Cr, and NAA/Cho ratios varied significantly (p < 0.05, p < 0.05, p < 0.05, respectively) between the 17 different locations measured in the brain in all eight patients and seven controls. Both the NAA/Cr ratios and the Cho/Cr ratios were also significantly lower in the gray matter than in the white matter (p < 0.0001) in both patients and controls, whereas the LL/Cr and NAA/Cho ratios were not significantly different. In conclusion, 2D-CSI MR spectroscopy may be useful in the early detection of metabolic CNS changes in NP

  9. Indication for and accuracy of CT and MRI of the temporomandibular joint

    Recurrent pains of the temporomandibular joint represent a frequent symptom with numerous different causes. CT and MRI can reliably show the cause of these disorders and therefore have substituted conventional X-ray imaging. Modern multi-slice-CT (MSCT) allows for examination of the skull base including the mandible in a very short time with thinnest slice collimation (0.75 mm). With 2D- and 3D- reformations reconstructed out of this volume data set in parasagittal, coronal or any other arbitrary slice orientation excellent imaging of fractures and bony changes of arthrosis as well as benign and malignant tumors of the temporomandibular joint can be performed. MRI offers very good soft tissue contrast in order to visualize the intra-articular disc, the ligaments and muscles, as well the possibility to acquire cross sectional images in any user-defined orientation. MRI is the method of choice to diagnose 'internal derangement', particularly displacement of the intra-articular disc and inflammatory disease of the temporomandibular joint. The present paper will provide diagnostic strategies for the use of MSCT or MRI imaging concerning the different causes of disorders to the temporomandibular joint. (orig.)

  10. Preliminary Reports on the Accuracy of Coronary CT-Angiography Using 64-slice Multi-slice Spiral CT (MSCT in Iran

    "A. Arjmand Shabestari

    2005-08-01

    Full Text Available Introduction & Background: Coronary artery disease (CAD is the leading cause of death in many western countries. Its prevalence and incidence among Irani-ans particularly in the urban areas are increasing. Ac-cording to the newest Tehran annual mortality re-port, the most common cause of death in Tehran is cardiovascular disease. Diagnostic gold standard in CAD is fluoroscopic coronary angiography (FCA us-ing catheterization. Nevertheless, it is an invasive method and in recent years, some non-invasive or less-invasive imaging modalities such as MRI and CT scans have been used to investigate CAD. One of the most attractive new methods in this regard is Coro-nary CT-Angiography (CCTA, which has gained considerable attention. Multi-slice spiral CT (MSCT scanners with simultaneous acquisition of multiple (up to 64 slices in less than half a second of gantry rotation time (in our study, 0.33 second, have be-come available, resulting in minimally-invasive coro-nary artery imaging. The purpose of this study is to determine the diagnostic accuracy of a new 64-slice MSCT scanner in the diagnosis of coronary artery and/or bypass grafts occlusion or hemodynamically significant stenosis. Parients & Methods: This investigation is underway in patients undergoing elective FCA. A 64-channel per rotation MSCT scanner (Somatom Sensation 64, Siemens Medical Systems, Forchheim, Germany, with 0.6 mm collimation, 0.33 second gantry rotation time and 120 KVp was used to perform CCTA. Ap-proximately 70-90 mL of a nonionic contrast medium was injected intravenously. All coronary artery seg-ments, according to American Heart Association (AHA classification & nomenclature system were analyzed. Patients who had undergone previous coronary artery bypass grafts (CABGs, or used coro-nary stents were enrolled in the study, as well. MSCT scans were carried out within 10 days of catheteriza-tion, and the most dramatically stenotic lesions were analyzed in CCTA by a semi

  11. Measurements of patient chest dose for multi-slice X-ray CT examinations using PIN photodiode dosimeters

    Organ and tissue doses delivered during chest CT examinations were measured as a function of scanning parameters including tube current, slice thickness, and pitch of the multi-slice CT scanner. Measurements were carried out by using a chest dosimetry phantom that incorporated lung and vertebra models, and by putting PIN photodiode dosimeters into the phantom at sites of the esophagus or stomach, lung, bone marrow, and skin. Absorbed doses at each site in the phantom measured for a constant scan area indicated that these values could be precisely calculated from the value obtained at any scanning parameter by using inverse proportionality of dose to pitch and the data of x-ray intensity as a function of tube current and slice thickness measured for the CT scanner used. Relative dose at each site was found to be constant regardless of the scanning parameters, indicating that the dose value at each site could be calculated from that measured at only one point in the phantom. Effective doses and effective dose equivalents were estimated from organ or tissue doses for chest CT examinations, and were found to be 1.5 to 3 times larger than the average values of effective dose equivalent appearing in the literature. (author)

  12. Investigation of an image artefact induced by projection noise inhomogeneity in multi-slice helical computed tomography

    Hsieh, Jiang

    2003-02-01

    The introduction of multi-slice helical computed tomography has fundamentally changed the way radiologists view CT images. Increasing numbers of clinical cases are examined with advanced visualization tools, such as maximum intensity projection, multi-planar reformation and volume rendering. It has been discovered that new image artefacts, which do not appear in the traditional two-dimensional reconstructed images, become visible in images generated by these new tools. In this paper, we investigate the causes of one such artefact, the Venetian blind artefact, which appears as bright-and-dark bands superimposed on three-dimensional images. We demonstrate that such an artefact is caused by the periodical noise variation in the reconstructed images. The image noise variation is, in turn, caused by the interaction of the noise inhomogeneity in the projections with the helical weights. An analytical formula is developed that accurately predicts the presence of such artefacts. Based on our analysis, several approaches are proposed for the artefact reduction or elimination.

  13. Radiation exposure in multi-slice versus single-slice spiral CT: results of a nationwide survey

    Multi-slice (MS) technology increases the efficacy of CT procedures and offers new promising applications. The expanding use of MSCT, however, may result in an increase in both frequency of procedures and levels of patient exposure. It was, therefore, the aim of this study to gain an overview of MSCT examinations conducted in Germany in 2001. All MSCT facilities were requested to provide information about 14 standard examinations with respect to scan parameters and frequency. Based on this data, dosimetric quantities were estimated using an experimentally validated formalism. Results are compared with those of a previous survey for single-slice (SS) spiral CT scanners. According to the data provided for 39 dual- and 73 quad-slice systems, the average annual number of patients examined at MSCT is markedly higher than that examined at SSCT scanners (5500 vs 3500). The average effective dose to patients was changed from 7.4 mSv at single-slice to 5.5 mSv and 8.1 mSv at dual- and quad-slice scanners, respectively. There is a considerable potential for dose reduction at quad-slice systems by an optimisation of scan protocols and better education of the personnel. To avoid an increase in the collective effective dose from CT procedures, a clear medical justification is required in each case. (orig.)

  14. The Correlation Between Age and Bleeding Volume in Haemorrhagic Stroke Using Multi Slice CT at District Hospitals in Jakarta.

    Saefudin, Tatan; Apriantoro, Nursama Heru; Hidayat, Ekaputra Syarif; Purnamawati, Schandra

    2016-04-01

    Haemorrhagic Stroke is a common disease in Indonesia. The best imaging modality for this disease is Multi Slice Computed Tomography Scanning (MSCT), as it may help strengthening the diagnosis as well as determining the brain bleeding volume. This study aimed to show correlation between bleeding volume of the brain and patient's age using cross-sectional approach. The 68 samples in this study were taken from secondary data from Head CT Scan of Haemorrhagic Stroke cases.  Brain bleeding volume is the dependent variable, obtained through slice thickness of 5 mm and ABC/2 method with software measurement in MSCT Scan device. The independent variable of this study is the patient's age. The result of the study was the average brain's bleeding volume of 21.76 ml ± 2.48 ml (range of 1.04 ml to 94.73 ml).The slice thickness using ABC/2 method, has a significant correlation with brain's bleeding volume in MSCT Scan examination, with correlation coefficient value r of 0.79. Brain bleeding volume in patients who have ages lower than 50 years and more or equal to 50 years were (18.93 ± 3.26) ml and (23.53 ± 3.47) ml respectively. There is no correlation between age and brain's bleeding volume in haemorrhagic stroke cases, with p value of 0.18, r = 0.19. PMID:26573030

  15. Low-dose multi-slice CT (LMCT) assessment of pulmonary emphysema in public-school teachers

    Although rates of emphysematous change in smokers have been reported previously, the precise effects of smoking on emphysematous change have not been established because the study subjects of previous reports were heterogeneous. This study was designed to determine the incidence of emphysematous change identified by low-dose multi-slice CT (LMCT) imaging in public-school teachers. We reviewed 1776 consecutive subjects (ages from 31 to 61 years) who had undergone LMCT scanning during health care examinations. In addition, their replies to questionnaires about smoking were obtained. Emphysematous change was found by LMCT imaging in 22 male smokers. In these 22 smokers, the scores of emphysematous change according to Goddard's method was well correlated with smoking history. According to the questionnaires, the smoking rates of male and female teachers were 56.7% and 4%, respectively. Eighty-five percent of the teachers worked in offices separated from smokers. Most smokers wished to quit smoking and most teachers knew the risk of nicotine as well as the rate of smoking among high school students. However, knowledge of the relationships between smoking and lung cancer, myocardial infarction, and subarachnoid hemorrhage were not adequate. Our present study clearly demonstrated the incidence of emphysematous change in school teachers. In addition, early exposure to information about the risks of smoking is believed to be important for students, but school teachers did not have enough of such information. (author)

  16. Noninvasive detection of coronary abnormalities in pediatric patients with Kawassaki disease using multi-slice spiral CT

    Objective: To evaluate the feasibility and value of detecting coronary artery lesions in Kawasaki disease using multi-slice computed tomography (MSCT). Methods: Thirty-four pediatric patients underwent 16-slice or 64-slice CT coronary, angiography. 18 patients were also examined with 2 dimension echocardiography (2DE). In all cases, visibility of coronary artery segment was recorded. The diameter of the LCA, RCA were measured in MSCTA and compared with 2DE. Correlation coefficient of dimension and coincidence rate of two methods were calculated. Results: Coronary artery lesions were found in 14 patients (22 branches) of the 34 cases with KD on MSCT. Six cases were dialated, 3 cases were dialated with aneurysms, 2 cases had aneurysms without dialation. Coronary artery stenosis in 1 eases, calcification in 2 cases. Three cases had multiple aneurysms with the presence of alternate stenosis that made the artery a bead-like appearance. CC of LM and RCA were 0.85, 0.91, respectively (P>0.05). Three coronary artery aneurysm in the distal RCA was missed by 2DE. MSCT could not detect slight or moderate mitral regurgitation in 2 patients and artery wall thickening in 5 patients. Conclusion: MSCT would be an effective complementary or alternative method for CDEC to evaluate coronary artery lesions non-invasively in pediatric patients with Kawasaki disease. (authors)

  17. Estimating of patient dose in abdomen-pelvis CT exam as a function of scan techniques in single and multi slice spiral CT by Monte Carlo Method

    Computed tomography is a specialized x-ray imaging technique that has found increasing use since its introduction into diagnostic radiology in the early 1979 's. Although CT is a diagnostic imaging modality giving higher patient dose in comparison with other radiological procedure, but the good resolution of its images, increases the use of this modality in diagnostic imaging with introduction of spiral CT in 1989 and multi slice spiral CT in the early 1990 's, some radiation protection committee tried to calculate the patient dose during CT exam. Since the direct measurement of patient dose and its relation with scan techniques such as mA, KV, Pitch and slice thickness is very difficult , the Monte Carlo method was introduced as the most powerful tool for measuring the organ and patient absorbed dose. Nowadays , the predominant method for assessment of patient's organ absorbed dose is the application of conversion coefficients established by use of Monte Carlo simulation, one of the most famous dose calculation software is CT dosimetry which makes use of the NRPB Monte Carlo dose data sets produced in report SR 250. In this work we use CT Dosimetry Monte Carlo package for measurement of the relationship between the patient dose and scan techniques in mathematically standard phantom( Hermaphrodite 170 cm / 70 Kg) for an abdomen -pelvis scan in single and multi slice spiral CT. As we expected, by increasing the mA and KV the patient dose increases but the relation between the effective dose and mA is linear, also in both kind of scanners the patient dose increases with decreasing the pitch factor. And finally although the multi slice CT is faster than single slice systems, but the patient dose in multi slice systems is more than single slice scanners

  18. Application of the FDK algorithm for multi-slice tomographic image reconstruction; Aplicacao do algoritmo FDK para a reconstrucao de imagens tomograficas multicortes

    Costa, Paulo Roberto, E-mail: pcosta@if.usp.b [Universidade de Sao Paulo (IFUSP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear; Araujo, Ericky Caldas de Almeida [Fine Image Technology, Sao Paulo, SP (Brazil)

    2010-08-15

    This work consisted on the study and application of the FDK (Feldkamp- Davis-Kress) algorithm for tomographic image reconstruction using cone-beam geometry, resulting on the implementation of an adapted multi-slice computed tomography system. For the acquisition of the projections, a rotating platform coupled to a goniometer, an X-ray equipment and a digital image detector charge-coupled device type were used. The FDK algorithm was implemented on a computer with a Pentium{sup R} XEON{sup TM} 3.0 processor, which was used for the reconstruction process. Initially, the original FDK algorithm was applied considering only the ideal physical conditions in the measurement process. Then some artifacts corrections related to the projections measurement process were incorporated. The implemented MSCT system was calibrated. A specially designed and manufactured object with a known linear attenuation coefficient distribution ({mu}(r)) was used for this purpose. Finally, the implemented MSCT system was used for multi-slice tomographic reconstruction of an inhomogeneous object, whose distribution {mu}(r) was unknown. Some aspects of the reconstructed images were analyzed to assess the robustness and reproducibility of the system. During the system calibration, a linear relationship between CT number and linear attenuation coefficients of materials was verified, which validate the application of the implemented multi-slice tomographic system for the characterization of linear attenuation coefficients of distinct several objects. (author)

  19. Cerebral gliomas: prospective comparison of multivoxel 2D chemical-shift imaging proton MR spectroscopy, echoplanar perfusion and diffusion-weighted MRI

    Developments in MRI have made it possible to use diffusion-weighted MRI, perfusion MRI and proton MR spectroscopy (MRS) to study lesions in the brain. We evaluated whether these techniques provide useful, complementary information for grading gliomas, in comparison with conventional MRI. We studied 17 patients with histologically verified gliomas, adding multivoxel proton MRS, echoplanar diffusion and perfusion MRI the a routine MRI examination. The maximum relative cerebral blood volume (CBV), minimum apparent diffusion coefficient (ADC) and metabolic peak area ratios in proton MRS were calculated in solid parts of tumours on the same slice from each imaging data set. The mean minimum ADC of the 13 high-grade gliomas (0.92±0.27 x 10-3 mm2/s) was lower than that of the four low-grade gliomas (1.28±0.15 x 10-3 mm2/s) (P<0.05). Means of maximum choline (Cho)/N-acetylaspartate (NAA), Cho/creatine (Cr), Cho/Cr in normal brain (Cr-n) and minimum NAA/Cr ratios were 5.90±2.62, 4.73±2.22, 2.66±0.68 and 0.40±0.06, respectively, in the high-grade gliomas, and 1.65±1.37, 1.84±1.20, 1.61±1.29 and 1.65±1.61, respectively, in the low-grade gliomas. Significant differences were found on spectroscopy between the high- and low-grade gliomas (P<0.05). Mean maximum relative CBV in the high-grade gliomas (6.10±3.98) was higher than in the low-grade gliomas (1.74±0.57) (P<0.05). Echoplanar diffusion, perfusion MRI and multivoxel proton MRS can offer diagnostic information, not available with conventional MRI, in the assessment of glioma grade. (orig.)

  20. The study of the upper airway in obstructive sleep apnea hypopnea syndrome with multi-slice spiral CT

    Objective: To retrospectively investigate the upper airway (UA) characteristics of the obstructive sleep apnea hypopnea syndrome (OSAHS) with multi-slice spiral computed tomography (MSCT), and to analyze the value of MSCT in the clinical diagnosis and pathogeny research of OSAHS. Methods: The pharynxes of 28 cases with OSAHS and 14 controls were scanned by MSCT at the time of deep inspiration, deep expiration, normal respiration, and Mueller action. The cross-section area with its corresponding sagittal and transverse diameters at naso-, velo-, and tongue-pharyngeal level, the length and thickness of soft palate, the site and range of UA obstruction, and the pharyngeal collapsibility were measured and calculated, respective. Results: (1) MSCT with its software package could ideally and accurately help to observe the UA, measure the required data, and judge the range of UA obstruction. (2) Mean cross-section areas of velo-pharynx and tongue-pharynx in OSAHS were significantly less than those in the control group, which mostly occurred at the end of deep inspiration (P<0.05 ). (3) The collapsibilities at the velo-pharyngeal and tongue-pharyngeal levels in OSAHS were higher than those in the control group (F=15.133, P=0.001; F=5.552, P=0.025). (4) The soft palates of OSAHS were thicker than those in the controls (F=15.908, P=0.000). Conclusions: The straitness and the larger collapsibility at the velo-pharynx and tongue-pharynx are perhaps the main causes of OSAHS. MSCT is relatively convenient, quick, and accurate in the observation of the UA, thuspossessing the practical value in the clinical diagnosis and pathogeny research of OSAHS. (authors)

  1. Imaging skeletal anatomy of injured cervical spine specimens: comparison of single-slice vs multi-slice helical CT

    Our objective was to compare a single-slice CT (SS-CT) scanner with a multi-slice CT (MS-CT) scanner in the depiction of osseous anatomic structures and fractures of the upper cervical spine. Two cervical spine specimens with artificial trauma were scanned with a SS-CT scanner (HighSpeed, CT/i, GE, Milwaukee, Wis.) by using various collimations (1, 3, 5 mm) and pitch factors (1, 1.5, 2, 3) and a four-slice helical CT scanner (LightSpeed, QX/i, GE, Milwaukee, Wis.) by using various table speeds ranging from 3.75 to 15 mm/rotation for a pitch of 0.75 and from 7.5 to 30 mm/rotation for a pitch of 1.5. Images were reconstructed with an interval of 1 mm. Sagittal and coronal multiplanar reconstructions of the primary and reconstructed data set were performed. For MS-CT a tube current resulting in equivalent image noise as with SS-CT was used. All images were judged by two observers using a 4-point scale. The best image quality for SS-CT was achieved with the smallest slice thickness (1 mm) and a pitch smaller than 2 resulting in a table speed of up to 2 mm per gantry rotation (4 points). A reduction of the slice thickness rather than of the table speed proved to be beneficial at MS-CT. Therefore, the optimal scan protocol in MS-CT included a slice thickness of 1.25 mm with a table speed of 7.5 mm/360 using a pitch of 1.5 (4 points), resulting in a faster scan time than when a pitch of 0.75 (4 points) was used. This study indicates that MS-CT could provide equivalent image quality at approximately four times the volume coverage speed of SS-CT. (orig.)

  2. Multi-slice spiral CT 3D reconstruction of extrahepatic feeding arteries in hepatocellular carcinoma:its clinical applications

    Objective: To discuss the feasibility of displaying the extrahepatic feeding arteries in hepatocellular carcinoma with the help of multi-slice spiral CT 3D reconstruction and to assess the clinical value of this technique. Methods: Triple-phase enhanced CT scanning with a 64-slice spiral CT scanner was performed in 89 patients with advanced primary hepatocellular carcinoma (HCC). Three-dimensional reconstruction techniques, including maximum intensity projection (MIP) and volume rendering (VR), with arterial phase images, were used to display the origination and course of both the intrahepatic and extrahepatic supplying arteries of HCC. The results were compared with the angiographic findings. Results: Of 59 cases with massive type HCC, extrahepatic supplying arteries were found in 33. In 21 cases of diffuse type HCC four showed extrahepatic supplying arteries,and in nine cases of nodular type HCC only one had extra-hepatic supplying arteries. The HCC could get their extrahepatic blood supply via eight pathways. A total of 44 extrahepatic supplying arteries were detected,and 19 anomalously originated hepatic arteries were found. Conclusion: The extrahepatic supplying arteries in hepatocellular carcinoma are common findings and their supplying pattern are extremely varied, which may be associated with the type and location of the tumors. Three-dimensional reconstruction technique with the help of triple-phase enhanced CT scanning on a 64-slice spiral CT scanner can provide excellent images as vivid and ideal as angiography can afford. Therefore,the times of angiography examination, the use of contrast media as well as the dose of radiation to both the patients and the physicians can be reduced as far as possible. The detailed information about extrahepatic blood supply is very useful for improving the therapeutic result of HCC. (authors)

  3. Accuracy and reliability of quantitative measurements in coronary arteries by multi-slice computed tomography: Experimental and initial clinical results

    AIM: To evaluate the accuracy of non-invasive measurements within coronary arteries by multi-slice computed tomography (MSCT). We present experimental as well as clinical data. MATERIALS AND METHODS: Silicon tubes simulating coronary arteries (outer diameter 6 mm, lumen diameter within stenotic area 2 mm) were used for experimental studies. Clinical data were derived from 15 patients in whom vessel diameters were assessed by MSCT, intracoronary ultrasound (ICUS) and quantitative coronary angiography (QCA). MSCT were performed in a Somatom Volume ZoomTMCT system (Siemens, Forchheim, Germany) at 2 collimated slice widths (2.5 mm, 1.0 mm). RESULTS: Outer silicon tube diameters were overestimated by MSCT (6.56 mm ± 0.32 mm). All measurements revealed significantly better results on 1.0 collimation compared to 2.5 mm collimation (outer diameter: 6.36 mm ± 0.22 mm vs 6.76 mm ± 0.27 mm, P < 0.0001; lumen diameters: 1.83 mm ± 0.14 mm vs 1.51 mm ± 0.19 mm,P < 0.0001). The comparison of vessel diameters within human coronary arteries revealed comparable results between ICUS and MSCT (4.89 mm ± 0.67 mm vs 4.91 mm ± 0.71 mm, P = 0.79,r = 0.79, P < 0.0001). QCA-measurements showed significantly lower results (3.67 ± 0.71, P < 0.0001,r = 0.62, P < 0.001). CONCLUSIONS: Experimental as well as initial clinical results indicate acceptable reliability and accuracy of quantitative measurements by MSCT, when using thin collimated slice widths. Partial volume effects lead to a systematic overestimation of vessel size. MSCT has the potential to become an important non-invasive diagnostic tool in patients with coronary artery disease. Schroeder, S. et al. (2001)

  4. Effect of different injection rates of contrast medium on hepatic perfusion by using multi-slice spiral CT

    Objective: To access the effect of different injection rates of contrast medium on hepatic perfusion by using multi-slice spiral CT (MSCT). Methods: Sixty volunteers underwent liver dynamic CT scan, they were divided into three groups according to different injection rate of contrast medium (4 ml/s, 5 ml/s, and 7 ml/s, respectively). Their hepatic perfusion parameters were calculated and the results were compared between the three groups. Results: There are five perfusion data: hepatic arterial perfusion (HAP), hepatic portal perfusion (HPP), total liver perfusion (TLP), hepatic arterial perfusion index (HPI), hepatic portal perfusion index ( PPI). There is no significant difference of all indexes when compared 4 ml/s to 5 ml/s group, and 5 ml/s to 7 ml/s group, whereas HAP, HPP and TLP of 4 ml/s group were significant higher than those of 7 ml/s group. HAP: (0.37 ± 0.16) ml·min-1·ml-1 vs (0.26 ± 0.10) ml·min-1·ml-1, t=0.105, P=0.010; HPP: (0.68 ±0.19) ml·min-1 ml-1 vs (0.51±0.13) ml·min-1·ml-1, t=0.172, P=0.001; TLP: (1.05±0.30) ml·min-1·ml-1 vs (0.77±0.18) ml·min-1·ml-1, t=0.277, P=0.001. Conclusion: When evaluate liver perfusion with MSCT, the higher the injection rate of contrast medium, the lower the perfusion data. In clinical practice, perfusion effect, security and condition of patient should thought over to select a proper injection rate. To this study, 5 ml/s is enough. (authors)

  5. Low-dose multi-slice CT with three dimensional rendering of the tendons of foot and ankle

    Objective: To study the feasibility and reasonability of low-dose multi-slice CT (MSCT) with three dimensional rendering of the tendons of foot, and ankle. The statistical methods including ANOVA and Kruskal-Wallis H was used. Methods: Forty-five consecutive patients with fractures of foot and ankle were enrolled and evenly grouped into A(80 kV, 100 mAs), B (110 kV, 60 mAs) and C (130 kV, 60 mAs). The MSCT scanning range was 6 slices of 1.0 mm. The CT value and standard deviation (SD) of the muscle and the CTDIvol were recorded. The image quality of volume rendering of the tendons was blindly evaluated. Results: The CT value of muscle in group A (71.6±12.0) HU was significantly higher than group B [(66.8±9.2) HU, P=0.010] and C [(66.1±7.1) HU, P=0.004]. The SD average values were 11.9, 6.1 and 7.0 HU for three groups, and there were significant differences among the three groups (F= 37.142, P=O.0000). Group A had the highest SD value, group C had the lowest. SD; CTDIvol average value were (3.01±0.08), (4.63±0.11), (7.02±0.24) mGy respectively, which were significant different among the three groups (H =39.185, P=0.000). Group A had the lowest CTDIvol, while group C had the highest CTDIvol. Volume rendering of the tendons was evaluated as 2.3±0.5, 3.7±0.5, 4.8± 0.4, and there were significant differences among the three groups (H=72.779, P=0.000). Group A had the worst VR images, while group C had the best VR images. All VR images in Group B were good for diagnosis. Conclusion: The protocol of 110 kV, 60 mAs, and 1 mm × 6 with three-dimensional volume rendering would be enough for evaluating the tendons of foot and ankle. (authors)

  6. Evaluation of the effects of tirofiban on myocardial infarction-reperfusion injury by delayed enhancement multi-slice spiral CT

    Objective: To evaluate the effects of tirofiban on myocardial no-reflow after acute myocardial infarction and reperfusion by delayed enhancement-multi-slice CT (DE-MSCT). Methods: Chinese mini pigs were randomized into control group and tirofiban treatment group. Acute myocardial infarction was induced by balloon occlusion of the medium segment of the left anterior descending artery for 90 minutes. Reperfusion was created by withdrawing the balloon during angiography. All successful models received DE-MSCT examinations at 1 h, 24 h, 48 h, and 72 h after reperfusion to observe the myocardial no- reflow area. Data were analyzed with Spearman rank correlation and Wilcoxon, Rank Sum test. Results: Six pigs were successfully induced as acute reperfusion myocardial infarction in each group. Furthermore,4 pigs in control group and 3 pigs in tirofiban treatment group had no-reflow phenomenon. The no-reflow volume percent increased from 1 h to 72 h in both groups. The no-reflow volume percent was significantly reduced in tirofiban treatment group compared with control group after reperfusion at 1 h, 24 h, 48 h and 72 h respectively [(4.78±0.66)% and (9.62±3.05)%, t=6.000, P<0.05; (5.84±1.19)% and (13.44±3.33)%, t=6.000, P<0.05; (6.41±1.24)% and (15.10±3.76)%, t=6.000, P<0.05; (6.63±0.82)% and (15.94±4.62)%, t=6.000, P<0.05], as well as the infarct myocardium volume percent was significantly reduced in tirofiban treatment group compared with control group at 24 h, 48 h and 72 h after reperfusion [(19.74±2.94)% and (25.08±4.68)%, t=25.000, P<0.05; (20.34±2.46)% and (27.07±5.44)%, t=26.000, P<0.05; (20.72±2.10)% and (26.17±5.19)%, t=24.000, P< 0.05]. Conclusions: DE-MSCT can be used to detect the extent of no-reflow phenomenon. Tirofiban can reduce the volume of myocardial infarct and no-reflow area after reperfusion. (authors)

  7. Study of low dose and dynamic multi-slice CT about obstructive sleep apnea syndrome in sleeping

    Objective: To perform Low dose dynamic MSCT(multi-slice CT) in sleeping obstructive sleep apnea syndrome (OSAS) patients correcting the imprecise measure values in waking state, and to exactly analyse the location and extension of the dynamic changes about the condition. Methods: Sixteen OSAS patients were scanned both in waking and naturally sleeping period (end phase of inspiration and expiration). Measured at the narrowest part of the retropalatal (RP) and retroglossal (RG) and 5 mm under the tip of epiglottis at the epiglottal (EPG)at the end period of inspiration in sleeping, respectively, and compared the accurate position of the narrowest or occlusive level in 3 phases. All patients were also scanned using cine mode at the narrowest level at the end period of inspiration in sleeping to show the pharyngeal cavity changes during sleep. Results: The smallest XSA of RP region (Mw=47.50 mm2, Me=73.00 mm2, Mi=2.00 mm2; Zwe=2.897, Pwe=0.003; Zwi=4.192, Pwiie=4.538, Piew=8.00 mm, Me=9.50 mm, Mi=1.50 mm; Zwe=1.933, Pwe=0.056; Zwi=3.720, Pwiie=4.230, Piew=8.00 mm, Me=9.00 mm, Mi=1.00 mm; Zwe=1.210, Pwe=0.246; Zwi=4.203, Pwiie=4.557, Piew=4.00 mm3, Me=5.50 mm3, Mi=1.50 mm3; Zwe=1.576, Pwe=0.125; Zwi=3.532, Pwiie=4.077, Piew=7.00 mm, Me=6.00 mm, Mi=10.50 mm; Zwe=0.557, Pwe=0.603; Zwi=2.541, Pwi=0.011; Zie=2.852, Pie=0.004) and RG regions (Mw=5.00 mm, Me=3.00 mm, Mi=9.50 mm; Zwe=0.747, Pwe=0.482; Zwi=2.657, Pwi=0.007; Zie=3.075, Pie=0.001), were different between inspiration and expiration of sleeping or awake. The dynamic cine CT scan during sleeping could show pharyngeal change, clearly. Conclusion: At the end period of inspiration in sleeping, the location of narrow or obstructive of airway is the most precise and sensitive and the false negative at the waking could be obviously reduced. Low dose MSCT scan reduced exposure and expense. (authors)

  8. The investigation of the lateral atlanto-dental interval of atlanto-axial joint by multi-slice spiral CT

    Objective: To explore imaging features of the lateral atlanto-dental interval (LADI) of atlanto-axial joint and its value in the diagnosis of atlanto-axial joint dislocation/subluxation. Methods: Two hundred and forty healthy volunteers without atlanto-axial joint dysfunction and 32 patients with torticollis and/or functional impairment at atlanto-axial.joint were enrolled into this study. All subjects were examined with multi-slice CT in both neutral and max rotation positions to the left/right. Clinical endpoints including VBLADI, variance range of the VBLADI and asymmetric conditions were evaluate. χ2 test is used to evaluate the variance of incidence of bilateral LADI asymmetry in different age groups, Pearson-test (2-tailed) is used to evaluate the correlation between VBLADI and rotary function of atlanto-axial joint, precise test of fourfold table is used to compare normal group with patient groups. Results: (1) In the normal control group: asymmetry of bilateral LADI were observed in 204 among 240 (85.00%) healthy volunteers including 60 youngsters (95% of ∣ VBLADI ∣ were 0.850 mm, 2.450 mm in the young (95% in the young and in the adult respectively. There was no correlation between VBLADI(-2.146 to 2.114 mm, Median 0.000 mm) and LA (22.949° to 44.649°, Median 34.500°), RA (25.284° to 45.334°, Median 35.300°), VLRA (-11.643° to 8.623°, median 0.000°) respectively in normal people (r=-0.030, -0.005, 0.026, P>0.05). (2) In the study with 32 patients including 25 youngsters (95% in group AALSD and group AACD than in abnormal group (P<0.01), but there is no difference between group AARD and normal group (P=0.738). Conclusion: The imaging finding of 'asymmetry of bilateral LADI' may be either a physiological variation or a pathological condition, clinical manifestations and other imaging findings should be evaluated to make a diagnosis. (authors)

  9. Comparative study of myocardial perfusion imaging and 64 multi-slice spiral CT for the diagnosis of coronary artery disease

    Objective: To compare the diagnostic value of myocardial perfusion imaging (MPI) and 64 multi-slice spiral CT (64-MSCT) for coronary artery disease (CAD). Methods: Fifty-two patients with suspected or known CAD were included in the study. Each patient underwent both stress and rest MPI, MSCT as well as conventional coronary angiography (CAG) within 1 month. The stress and rest MPI were scored by a 5-grade criteria (0-4) based on 17 coronary artery segments. The difference between summed stress and rest scores > 1 was defined as myocardial ischemia. Stenosis in one main vessel or one main branch of the main vessel ≥50% was defined as myocardial ischemia by MSCT. CAG was used as the reference for comparison. Statistical analysis was performed using SPSS 13.0 software. Kappa value was used to test the accordance of MPI and MSCT results. χ2 test was used to evaluate the difference between MPI and MSCT results. Results: The patient-based sensitivity, specificity, positive and negative predictive values and accuracy of MPI and MSCT for the diagnosis of CAD were 86.7% (26/30), 77.3% (17/22),83.9% (26/31), 81.0% (17/21), 82.7% (43/52) and 83.3% (25/30), 86.4% (19/22), 89.3%( 25/28), 79.2% (19/24), 84.6% (44/52), respectively. The vessel-based sensitivity, specificity, positive and negative predictive values and accuracy of MPI and MSCT were 74.5% (38/51), 81.0% (85/105), 65.5% (38/58), 86.7% (85/98), 78.8% (123/156) and 90.2% (46/51), 88.6% (93/105),79.3 % (46/58), 94.9% (93/98), 89.1% (139/156), respectively. There was no statistically significant difference between MPI and MSCT for either patient or lesion-based diagnosis (χ2 =0.44, 0.21, both P>0.05). 96.0% (24/25) patients with both abnormal MPI and MSCT positive were validated by CAG while 83.3% (15/18) patients with both MPI and MSCT negative were excluded by CAG. Conclusions: Both MPI and MSCT are reliable diagnostic modalities for CAD. They also provide complementary diagnostic value to each other. (authors)

  10. Indication for and accuracy of CT and MRI of the temporomandibular joint; Indikation und Aussagekraft von Computertomographie und Magnetresonanztomographie des Kiefergelenks

    Greess, H.; Anders, K. [Erlangen-Nuernberg Univ. (Germany). Inst. fuer Diagnostische Radiologie

    2005-07-01

    Recurrent pains of the temporomandibular joint represent a frequent symptom with numerous different causes. CT and MRI can reliably show the cause of these disorders and therefore have substituted conventional X-ray imaging. Modern multi-slice-CT (MSCT) allows for examination of the skull base including the mandible in a very short time with thinnest slice collimation (0.75 mm). With 2D- and 3D- reformations reconstructed out of this volume data set in parasagittal, coronal or any other arbitrary slice orientation excellent imaging of fractures and bony changes of arthrosis as well as benign and malignant tumors of the temporomandibular joint can be performed. MRI offers very good soft tissue contrast in order to visualize the intra-articular disc, the ligaments and muscles, as well the possibility to acquire cross sectional images in any user-defined orientation. MRI is the method of choice to diagnose 'internal derangement', particularly displacement of the intra-articular disc and inflammatory disease of the temporomandibular joint. The present paper will provide diagnostic strategies for the use of MSCT or MRI imaging concerning the different causes of disorders to the temporomandibular joint. (orig.)

  11. Investigation on the optical scan condition for imaging of multi-slice spiral CT liver perfusion in rats

    BAI Rong-jie; WANG Jin-e; JIANG Hui-jie; HAO Xue-jia; DONG Xu-peng; HUANG Ya-hua; WEI Lai

    2013-01-01

    Background Multi-slice CT liver perfusion has been widely used in experimental studies of hemodynamic changes in liver lesions,and is usually performed as an adjunct to a conventional CT examination because of its high temporal and spatial resolution,simple protocol,good reproducibility,and ability to measure hemodynamic changes of liver tissues at the capillary level.Experimental rat models,especially those of induced liver cancer,are often used in studies of hemodynamic changes in liver cancer.Carcinogenesis in rats has a similar pathological progression and characteristics resembling those in human liver cancer; as a result,rat models are often used as ideal animal models in the study of human liver cancer.However,liver perfusion imaging in rats is difficult to perform,because rats' livers are so small that different concentrations,flow rates,and dose of contrast agents during the CT perfusion scanning can influence the quality of liver perfusion images in rats.The purpose of this study,therefore,was to investigate the optimal scan protocol for the imaging of hepatic perfusion using a deconvolution mathematical method in rats by comparing the results of rats in different injection conditions of the contrast agent,including concentration,rate and time.Methods Plain CT scan conditions in eighty 2-month-old male Wistar rats were 5.0 mm slice thickness,5.0 mm interval,1.0 pitch,120 kV tube voltage,60 mA tube current,512×512 matrix,and FOV 9.6 cm.Perfusion scanning was carried out with different concentrations of diatrizoate (19%,38%,57%,and 76%),different injection rates (0.3 and 0.5 mi/s),and different injection times (1,2-3,4-5,and 6 seconds).The above conditions were randomly matched and adjusted to determine the best perfusion scan protocol.Thrae-phase contrast-enhanced scanning was performed after CT perfusion.Histological examination of the liver tissues with hematoxylin and eosin stains was done after CT scanning.Results When the concentration of the

  12. Peripheral pulmonary nodules: Relationship between multi-slice spiral CT perfusion imaging and tumor angiogenesis and VEGF expression

    , PS of inflammatory nodule were significantly lower than that of peripheral lung cancer (all P < 0.05). PH, PHpm/PHa, BF, and BV of benign nodule were significantly lower than those of inflammatory nodule (all P < 0.05), rather than PS and MTT (mean transit time) (all P > 0.05). PH, PHpm/PHa, BV, and PS of benign nodule were significantly lower than those of peripheral lung cancer (all P < 0.05). In the case of VEGF positive expression, MVD was positively correlated with PH, PHpm/PHa, BF, BV, and PS of peripheral lung cancer and PS of benign nodule (all P < 0.05). Multi-slice spiral CT perfusion imaging closely correlated with tumor angiogenesis and reflected MVD measurement and VEGF expression. It provided not only a non-invasive method of quantitative assessment for blood flow patterns of peripheral pulmonary nodules but also an applicable diagnostic method for peripheral pulmonary nodules

  13. Multi-slice imAGe generation using intra-slice paraLLel imaging and Inter-slice shifting (MAGGULLI)

    Kim, Dongchan; Seo, Hyunseok; Oh, Changheun; Han, Yeji; Park, HyunWook

    2016-02-01

    For acceleration of imaging time, multi-band imaging techniques (e.g. CAIPIRINHA) use the sensitivity differences of the multi-channel RF coils in the slice selection direction. To more effectively utilize the RF coil characteristics than the conventional multi-band imaging techniques, we propose a new imaging technique, called multi-slice image generation using intra-slice parallel imaging and inter-slice shifting (MAGGULLI). The proposed technique used an inter-slice shifting gradient in slice selection direction to make multi-slice images shift in the frequency encoding direction. Thus, aliasing caused by sub-sampling in the phase encoding direction is orthogonal to that by multi-band imaging with the inter-slice shifting, both of which are resolved by using the sensitivity information of the RF coil. Phantom and in vivo imaging experiments for the acceleration factors up to 10 demonstrate that the quality of the images reconstructed by MAGGULLI are better than that of CAIPIRINHA for high acceleration factors in the qualitative and quantitative analysis.

  14. Diagnosis of pulmonary embolism and the underlying venous thrombosis by multi-slice CT; Diagnostik der Lungenembolie und zugrundeliegender Venenthrombosen in der Mehrzeilen-Spiral-CT

    Mueller, C.; Kopka, L.; Funke, M.; Funke, C.; Grabbe, E. [Abt. Roentgendiagnostik I, Georg-August-Univ. Goettingen (Germany)

    2001-06-01

    To determine the value of multi-slice CT for the diagnosis of acute pulmonary embolism and an underlying venous thrombosis. Methods: 70 patients with clinically suspected acute pulmonary embolism were examined. Using multi-slice CT a combined examination of the pulmonary arteries and the veins of the lower limb, pelvis and abdomen was performed. Only one single bolus of 150 ml iopromid 300 was injected into a cubital vein with a flow of 4 ml/s. First, the pulmonary arteries were scanned with a slice thickness of 2.5 mm and a pitch of 1.5. On arrival of the contrast medium at the popliteal veins, indicated by bolus trakking, the veins of the lower limbs up to the end of the inferior vena cava were imaged using a slice thickness of 3.75 mm and a pitch of 1.5. The results could be compared with a ventilation-perfusion scan in 48 cases, with a Doppler ultrasound examination in 46 cases, and with a venography in 10 cases. Furthermore, the image quality of all arterial and venous regions was subjectively assessed. Results: In all patients who underwent multi-slice CT the pulmonary arteries as well as the veins of the lower half of the body could be recorded completely. Regarding the pulmonary arteries the image quality showed excellent results for the central and segmental arteries. The region up to the 3rd division in subsegmental branches could be sufficiently judged. More peripherally, a diagnostic assessment was not possible. The image quality of the veins was excellent in all sections, except the calf, where a reliable diagnosis could not be made. The comparison with the other techniques confirmed the superiority of multi-slice CT concerning the central and segmental pulmonary arteries and the veins from the popliteal vein to the inferior vena cava. In contrast, peripheral pulmonary emboli can be detected more certainly in ventilation/perfusion scans. The veins of the calf can be evaluated more reliably with venography. (orig.) [German] Evaluation der Moeglichkeiten

  15. Depiction of the triangular fibro-cartilage in patients with ulnar-sided wrist pain: comparison of direct multi-slice CT arthrography and direct MR arthrography

    Omlor, Georg; Jung, Martin [Orthopaedic University Hospital, Department of Hand and Elbow Surgery, Heidelberg (Germany); Grieser, Thomas; Ludwig, Karl [Orthopaedic University Hospital, Department of Diagnostic Radiology, Heidelberg (Germany)

    2009-01-15

    To compare direct multi-slice CT arthrography (MSCT-AG) and direct MR arthrography (MR-AG) of the wrist with regard to the depiction of the triangular fibro-cartilage (TFC). Fifteen consecutive patients with ulnar-sided wrist pain suspicious for TFC tear underwent both MSCT-AG and MR-AG of the wrist. Images obtained were evaluated by two radiologists in a blinded fashion for the depiction of six anatomical areas (radial, central and ulnar portion on the proximal and distal side) of the TFC by means of a five-point scoring system (1= excellent visibility to 5= not visible). Scores for MSCT-AG and MR-AG were compared using the Student's t-test. Mean scores for MSCT-AG and MR-AG, respectively, were 2.5/2.0, 3.2/2.5 and 2.8/2.4 for the radial, central and ulnar portion of the TFC on its proximal side, and 2.7/2.0, 3.1/2.3 and 2.9/2.4 for the radial, central and ulnar portion on its distal side (n=15). Paired Student's t-test showed no significant difference between MSCT-AG and MR-AG (P>0.05). In a first, small series, depiction of the TFC with MSCT-AG is comparable to that of MR-AG. Further evaluation of direct multi-slice CT arthrography of the wrist in a larger patient population would be promising. (orig.)

  16. Depiction of the triangular fibro-cartilage in patients with ulnar-sided wrist pain: comparison of direct multi-slice CT arthrography and direct MR arthrography

    To compare direct multi-slice CT arthrography (MSCT-AG) and direct MR arthrography (MR-AG) of the wrist with regard to the depiction of the triangular fibro-cartilage (TFC). Fifteen consecutive patients with ulnar-sided wrist pain suspicious for TFC tear underwent both MSCT-AG and MR-AG of the wrist. Images obtained were evaluated by two radiologists in a blinded fashion for the depiction of six anatomical areas (radial, central and ulnar portion on the proximal and distal side) of the TFC by means of a five-point scoring system (1excellent visibility to 5= not visible). Scores for MSCT-AG and MR-AG were compared using the Student's t-test. Mean scores for MSCT-AG and MR-AG, respectively, were 2.5/2.0, 3.2/2.5 and 2.8/2.4 for the radial, central and ulnar portion of the TFC on its proximal side, and 2.7/2.0, 3.1/2.3 and 2.9/2.4 for the radial, central and ulnar portion on its distal side (n=15). Paired Student's t-test showed no significant difference between MSCT-AG and MR-AG (P>0.05). In a first, small series, depiction of the TFC with MSCT-AG is comparable to that of MR-AG. Further evaluation of direct multi-slice CT arthrography of the wrist in a larger patient population would be promising. (orig.)

  17. Interpolated compressed sensing for 2D multiple slice fast MR imaging.

    Yong Pang

    Full Text Available Sparse MRI has been introduced to reduce the acquisition time and raw data size by undersampling the k-space data. However, the image quality, particularly the contrast to noise ratio (CNR, decreases with the undersampling rate. In this work, we proposed an interpolated Compressed Sensing (iCS method to further enhance the imaging speed or reduce data size without significant sacrifice of image quality and CNR for multi-slice two-dimensional sparse MR imaging in humans. This method utilizes the k-space data of the neighboring slice in the multi-slice acquisition. The missing k-space data of a highly undersampled slice are estimated by using the raw data of its neighboring slice multiplied by a weighting function generated from low resolution full k-space reference images. In-vivo MR imaging in human feet has been used to investigate the feasibility and the performance of the proposed iCS method. The results show that by using the proposed iCS reconstruction method, the average image error can be reduced and the average CNR can be improved, compared with the conventional sparse MRI reconstruction at the same undersampling rate.

  18. Establishing models of portal vein occlusion and evaluating value of multi-slice CT in hepatic VX2 tumor in rabbits

    Yue-Yong Qi; Li-Guang Zou; Ping Liang; Dong Zhang

    2007-01-01

    AIM: To establish models of portal vein occlusion of hepatic VX2 tumor in rabbits and to evaluate the value of multi-slice CT.METHODS: Forty New Zealand rabbits were divided into 4 groups according to digital table: Immediate group (group A; transplantation of tumor immediately after the portal vein occlusion), 3-wk group (group B;transplantation of tumor at 3 wk after the portal vein occlusion), negative control group (group C) and positive control group (group D), 10 rabbits in each group.Hepatic VX2 tumor was transplanted with abdominal-embedding innoculation immediately after the portal vein occlusion and at 3 wk after the portal vein occlusion.Meanwhile, they were divided into negative control group (Left external branch of portal vein was occluded by sham-operation, and left exite was embedded and inoculated pseudoly) and positive control group (Transplanted tumor did not suffer from the portal vein occlusion). All rabbits were scanned with multi-slice CT.RESULTS: All 40 animals were employed in the final analysis without death. Tumor did not grow in both immediate group and 3-wk group. In 3-wk group, left endite was atrophied and growth of tumor was inhibited.The maximal diameter of tumor was significantly smaller than that in positive control group (2.55 ± 0.46 vs3.59 ± 0.37 cm, t = 5.57, P < 0.001). Incidences of metastasis in the liver and lung were lower in 3-wk group than those in positive control group (10% vs 40%, and 90% vs 100%, respectively). The expression intensities of the vascular endothelium growth factor (VEGF) in groups A, B, C and D were 0.10 ± 0.06, 0.66 ± 0.21, 0.28± 0.09 and 1.48 ± 0.32, respectively. VEGF expression level in the test group A was significantly lower than that in the negative control group C (t = 5.07; P < 0.001).In addition, VEGF expression in the test group B was significantly lower than that in the positive control group D (t = 6.38; P < 0.001). Scanning with multi-slice CT showed that displaying rate of

  19. Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data

    Klintstroem, Eva; Smedby, Oerjan [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); UHL County Council of Oestergoetland, Department of Radiology, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Moreno, Rodrigo [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Brismar, Torkel B. [KUS Huddinge, Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Stockholm (Sweden)

    2014-02-15

    Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference. Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained. The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini. The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT. (orig.)

  20. Assessment of Left Ventricular Volumes and Function: Intra individual Comparison of Multi-slice Spiral CT and Electron Beam CT in an Animal Model

    Purpose: To evaluate multi-slice spiral computed tomography (MSCT) for measurements of left ventricular volumes, ejection fraction (EF), and myocardial mass in comparison with electron beam CT (EBCT) as a reference method. Material and Methods: Six minipigs underwent both standardized contrast-enhanced MSCT (effective acquisition time per cardiac cycle 125.7±30.1 ms, reconstructed slice thickness 8 mm) and EBCT (acquisition time 50 ms, collimated slice thickness 8 mm). The contrast-to-noise ratio of the left ventricle was measured in each animal, and the contour sharpness of the myocardium was analyzed. Volumes (EDV, ESV, SV) ejection fraction (EF), and muscle mass were calculated by MSCT and by EBCT using the slice summation method. Results: MSCT had a higher contrast-to-noise ratio and delineated the myocardial contours more sharply than EBCT. There was a close linear correlation between both modalities for all parameters (EDV: r P =0.88, ESV: r P =0.91, SV: r P =0.85, EF: r P =0.93; mass: r P =0.90; P <0.05 each). MSCT slightly overestimated ESV and slightly underestimated SV and EF compared with EBCT ( P <0.05 each). Conclusions: Image quality in MSCT is superior to that of EBCT. Functional parameters correlate well between both modalities, but the accuracy of MSCT is limited by its lower temporal resolution

  1. Rapid assessment of myocardial infarct size in rodents using multi-slice inversion recovery late gadolinium enhancement CMR at 9.4T

    Hausenloy Derek J

    2011-09-01

    Full Text Available Abstract Background Myocardial infarction (MI can be readily assessed using late gadolinium enhancement (LGE cardiovascular magnetic resonance (CMR. Inversion recovery (IR sequences provide the highest contrast between enhanced infarct areas and healthy myocardium. Applying such methods to small animals is challenging due to rapid respiratory and cardiac rates relative to T1 relaxation. Methods Here we present a fast and robust protocol for assessing LGE in small animals using a multi-slice IR gradient echo sequence for efficient assessment of LGE. An additional Look-Locker sequence was used to assess the optimum inversion point on an individual basis and to determine most appropriate gating points for both rat and mouse. The technique was applied to two preclinical scenarios: i an acute (2 hour reperfused model of MI in rats and ii mice 2 days following non-reperfused MI. Results LGE images from all animals revealed clear areas of enhancement allowing for easy volume segmentation. Typical inversion times required to null healthy myocardium in rats were between 300-450 ms equivalent to 2-3 R-waves and ~330 ms in mice, typically 3 R-waves following inversion. Data from rats was also validated against triphenyltetrazolium chloride staining and revealed close agreement for infarct size. Conclusion The LGE protocol presented provides a reliable method for acquiring images of high contrast and quality without excessive scan times, enabling higher throughput in experimental studies requiring reliable assessment of MI.

  2. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Lambrichts, Ivo, E-mail: Ivo.Lambrichts@uhasselt.b [Department of Basic Medical Sciences, Histology and Electron Microscopy, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Sun Yi, E-mail: Sunyihello@hotmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Denis, Kathleen, E-mail: kathleen.denis@groept.b [Department of Industrial Sciences and Techology-Engineering (IWT), XIOS Hogeschool Limburg, Hasselt (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium)

    2010-08-15

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

  3. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

  4. Long-term follow-up of surgically excluded popliteal artery aneurysms with multi-slice CT angiography and Doppler ultrasound

    The purpose of this study was to evaluate the role of multi-slice computed tomography (MSCT) angiography in the follow-up of popliteal artery aneurysms (PAAs) that have been operated on. Aneurysm exclusion and progression, graft patency and graft-related complications were analyzed. Fourteen patients with 21 surgically excluded PAAs were evaluated with MSCT angiography with slice thickness of 1.25 mm. The mean follow-up time was 67 months. MSCT demonstrated blood flow in six non-excluded PAAs (24%), with an average increase in the diameter of 21 mm over time. Fifteen PAAs demonstrated no blood flow and revealed an average decrease of 7 mm in diameter. The origin of this residual perfusion was demonstrated, and collaterals were involved in five of six non-excluded PAAs. In addition, MSCT demonstrated three graft stenoses. Furthermore, two occluded grafts were visualized. Twenty-four percent of the patients after surgical exclusion of PAAs revealed residual perfusion within the aneurysmal sac during follow-up, with a significant increase in the aneurysmal size with MSCT. Moreover, evaluation of the graft patency could also be done as could demonstration of anastomotic abnormalities. Thus, MSCT might be considered as a new tool to evaluate residual collateral feeding of popliteal aneurysmal sac and could be useful in identification and localization of feeding vessels. (orig.)

  5. 卵巢囊性畸胎瘤B超及多排螺旋CT的诊断价值比较%Comparison of the diagnostic value of ovarian cystic teratoma B ultrasound and multi-slice spiral CT

    樊兆丽; 彭明洋

    2015-01-01

    Objective To investigate the diagnosis of ovarian cystic teratoma of B ultrasound and multi-slice spiral CT. Methods A retrospective analysis of 40 patients with surgically and pathologically confirmed ovarian cystic teratoma B ultrasound and CT image data.Results Multi-slice spiral CT diagnosis is higher than B ultrasound. Conclusion B ultrasound for routine screening, joint multi-slice spiral CT can improve diagnosis of ovarian cystic teratoma.%目的:探讨卵巢囊性畸胎瘤的B超及多排螺旋CT的诊断价值。方法:回顾性分析40例经手术及病理证实的卵巢囊性畸胎瘤的B超及CT影像资料。结果:多排螺旋CT的诊断符合率高于B超。结论:B超检查适用于常规筛选检查,联合多排螺旋CT检查,可提高卵巢囊性畸胎瘤的定性诊断。

  6. Evaluation of 2D multiband EPI imaging for high-resolution, whole-brain, task-based fMRI studies at 3T: Sensitivity and slice leakage artifacts

    Todd, Nick; Moeller, Steen; Auerbach, Edward J.; Yacoub, Essa; Flandin, Guillaume; Weiskopf, Nikolaus

    2016-01-01

    Functional magnetic resonance imaging (fMRI) studies that require high-resolution whole-brain coverage have long scan times that are primarily driven by the large number of thin slices acquired. Two-dimensional multiband echo-planar imaging (EPI) sequences accelerate the data acquisition along the slice direction and therefore represent an attractive approach to such studies by improving the temporal resolution without sacrificing spatial resolution. In this work, a 2D multiband EPI sequence was optimized for 1.5 mm isotropic whole-brain acquisitions at 3 T with 10 healthy volunteers imaged while performing simultaneous visual and motor tasks. The performance of the sequence was evaluated in terms of BOLD sensitivity and false-positive activation at multiband (MB) factors of 1, 2, 4, and 6, combined with in-plane GRAPPA acceleration of 2 × (GRAPPA 2), and the two reconstruction approaches of Slice-GRAPPA and Split Slice-GRAPPA. Sensitivity results demonstrate significant gains in temporal signal-to-noise ratio (tSNR) and t-score statistics for MB 2, 4, and 6 compared to MB 1. The MB factor for optimal sensitivity varied depending on anatomical location and reconstruction method. When using Slice-GRAPPA reconstruction, evidence of false-positive activation due to signal leakage between simultaneously excited slices was seen in one instance, 35 instances, and 70 instances over the ten volunteers for the respective accelerations of MB 2 × GRAPPA 2, MB 4 × GRAPPA 2, and MB 6 × GRAPPA 2. The use of Split Slice-GRAPPA reconstruction suppressed the prevalence of false positives significantly, to 1 instance, 5 instances, and 5 instances for the same respective acceleration factors. Imaging protocols using an acceleration factor of MB 2 × GRAPPA 2 can be confidently used for high-resolution whole-brain imaging to improve BOLD sensitivity with very low probability for false-positive activation due to slice leakage. Imaging protocols using higher acceleration

  7. Comparison of multi-slice CT (MSCT) and TI-201 myocardial SPECT in detection of coronary artery disease: relation to coronary arteriography

    To evaluate the diagnostic potentials of MSCT and TI-201 SPECT in the assessment of coronary artery disease. Twenty-four patients (15 men, 9 women, 42-79 years) with clinically suspected coronary artery disease were studied by TI-201 myocardial SPECT and MSCT. MSCT data were obtained with 12 x 0.75 mm, 420ms rotation, multi-slice CT scanner (SOMATOM Sensation, Siemens) using non-ionic contrast, 80ml, 4ml/sec. Multiplanar reconstruction techniques were used for evaluation of coronary arteries. TI-201 myocardial SPECT were performed at stress with adenosine and at rest. Data from MSCT and TI-201 SPECT were compared territory by territory (divided into two segments; LAD and RCA/LCx) and related to coronary arteriography, in which more than 60% stenoses are regarded as significant. MSCT and TI-201 SPECT showed agreement in 37 out of 48 segments (77.1%). Out of 11 disagreed segments (22.9), TI-201 SPECT was superior in 6 segments and MSCT was superior in 5 segments. Sensitivities and specificities of MSCT and TI-201 SPECT by coronary arteriography are 81.8%, 69.2% and 86.3%, 76.9%, respectively. Agreed 4 segments between MSCT and TI-201 SPECT exhibited results that differ from the results of coronary arteriography. Myocardial bridge in two cases were detected as significant stenoses by MSCT but showed normal perfusion in TI-201 SPECT. Agreement between MSCT and TI-201 SPECT in the assessment of coronary artery disease was good but TI-201 SPECT has higher sensitivity and specificity for the detection of jeopardized myocardium than MSCT. MSCT and TI-201 SPECT provide complementary information in the assessment of coronary artery disease and could help reduce probable mistake in the interpretation of hemo dynamically insignificant lesion in coronary arteriography

  8. Multi-slice abdominal CT in oncological patients. Influence of table feed and detector configuration on image quality and radiation exposure

    Purpose: To evaluate the image quality and radiation exposure of different spiral CT scanning parameters for routine staging examination of the abdomen in oncologic patients using a multi-slice CT scanner. Methods/Materials: Examination of 40 patients in 4 groups on a multislice CT scanner (Somatom VolumeZoom, Siemens AG, Forchheim). Functional detector width (4x2.5, 4x5 mm) and pitch (table feed in relation to collimated slice width) were varied (3 and 5). Tube voltage (120 kV), effective tube current (160 mAs), slice-thickness (6 mm), increment (4 mm), kernel (B 30), and contrast injection parameters were dept constant. Axial images were assessed by three radiologists regarding delineation of anatomic structures, artifacts, and overall image quality. Results: Significantly reduced image quality especially due to artifacts was observed using a 5 mm detector configuration with a pitch of 5 (scan time 9 sec). Image quality was rated best for a 2.5 mm detector configuration with a pitch of 3 and a scan time of 28 sec. The effective dose was independent of the pitch. However, the mean effective dose was 9% higher using the smaller detector configuration (9.9 mSv vs 10.9 mSv). Conclusions: For routine staging CT of the abdomen use of a 4x2.5 mm detector configuration with a pitch between 3 and 5 is recommended. A 4x5 mm detector configuration using overlapping data acquisition can also be recommended, but additional thin slice reformations are not possible. (orig.)

  9. 多层螺旋CT在先天性心脏病的应用现状%Application of multi-slice computed tomography in congenital heart disease

    陈险峰; 马小静; 江帆; 李林

    2014-01-01

    Congenital heart disease belongs to abnormal embryonic development of cardiovascular malformation. It has a lot of changes in pathology. So, it is very important to have a preoperative diagnosis before the operation. Multi-slice computed tomography (MSCT) can analyze illness comprehensive and provide significant proof for clinic. This article expounded the value and situation of it from the historical process of congenital heart disease, the way of check, the characteristic of diagnostic imaging and radiation dose. Clinical practice shows that the imaging advantage of MSCT apply to diagnose complex congenital heart disease. Meanwhile, we should use all kinds of technology to optimize scanning parameters, plan characteristic medical treatments and maximum lower the subjects' radiation dosage.%先天性心脏病属于胚胎发育异常的心血管畸形,其病理改变千差万别,术前诊断对手术治疗尤为重要;多层螺旋 CT 检查能全面分析疾病,为临床提供重要诊断依据。本文从多层螺旋CT检查复杂CHD的历史进程、检查方法、影像诊断特点、辐射剂量的控制四个方面阐述其应用现状。临床实践表明多层螺旋CT的成像优势适用于复杂CHD的诊断,同时应使用各种技术优化扫描参数,制订个性化检查方案,最大限度地降低受检者的辐射剂量。

  10. The evaluation of anti-angiogenic treatment effects for implanted rabbit VX2 breast tumors using functional multi-slice spiral computed tomography (f-MSCT)

    Lei Zhen, E-mail: leizhen2004@163.com [Department of Anatomy, Chinese Medical University, No. 92, Beiermalu Road, Heping District, Shenyang, 110001 (China) and Department of Radiology, The First Hospital of Liaoning Medical College, No. 2, Wuduan, Renmin Street, Jinzhou, 121001 (China); Ma Heji, E-mail: maheji9831@sina.com [Department of Radiology, The First Hospital of Liaoning Medical College, No. 2, Wuduan, Renmin Street, Jinzhou, 121001 (China); Xu Na, E-mail: xuna821230@sohu.com [Department of Radiology, The First Hospital of Liaoning Medical College, No. 2, Wuduan, Renmin Street, Jinzhou, 121001 (China); Xi Huanjiu, E-mail: xihuanjiu2004@yahoo.cn [Anthropology Institute, Liaoning Medical College, No. 40, Sanduan, Songpo Rd, Jinzhou, 121001 (China)

    2011-05-15

    Objective: Investigate the benefit of functional multi-slice spiral computed tomography (f-MSCT) perfusion imaging in the non-invasive assessment of targeted anti-angiogenesis therapy on an implanted rabbit VX2 breast tumor model. Method: 69 female pure New Zealand white rabbits were randomly assigned to one of the 4 groups and received treatment accordingly: control (saline), Endostar, neoadjuvant chemotherapy (Cyclophosphamide, Epirubicin and 5-Fluorouracil, CEF), combination therapy (Endostar and CEF). After 2 weeks of treatment, f-MSCT perfusion scannings were performed for all rabbits and information about blood flow (BF), blood volume (BV), mean transit time (MTT) and surface permeability (SP) was collected. After perfusion imaging, tumor tissues were sampled for immunohistochemistry and the Western blot test of VEGF protein expression. Results: (1) The VEGF expression level, measured by immunohistochemistry and Western blot, decreased by treatment group (control > Endostar > CEF > combination therapy). The same was true for the mean BF, BV, MTT and PS, which decreased from the control group to the combination therapy group gradually. The mean MTT level increased in reverse order from the control to the combination therapy group. The difference between any 2 groups on these measures was statistically significant (P < 0.05). (2) There was moderate positive correlation between VEGF expression and BE, BV, or PS level (P < 0.05) and a negative correlation between VEGF expression and MTT level for all 4 groups (P < 0.05). Conclusion: Therefore, f-MSCT can be used as a non-invasive approach to evaluate the effect of anti-angiogenic therapy for implanted rabbit VX2 breast tumors.

  11. The evaluation of anti-angiogenic treatment effects for implanted rabbit VX2 breast tumors using functional multi-slice spiral computed tomography (f-MSCT)

    Objective: Investigate the benefit of functional multi-slice spiral computed tomography (f-MSCT) perfusion imaging in the non-invasive assessment of targeted anti-angiogenesis therapy on an implanted rabbit VX2 breast tumor model. Method: 69 female pure New Zealand white rabbits were randomly assigned to one of the 4 groups and received treatment accordingly: control (saline), Endostar, neoadjuvant chemotherapy (Cyclophosphamide, Epirubicin and 5-Fluorouracil, CEF), combination therapy (Endostar and CEF). After 2 weeks of treatment, f-MSCT perfusion scannings were performed for all rabbits and information about blood flow (BF), blood volume (BV), mean transit time (MTT) and surface permeability (SP) was collected. After perfusion imaging, tumor tissues were sampled for immunohistochemistry and the Western blot test of VEGF protein expression. Results: (1) The VEGF expression level, measured by immunohistochemistry and Western blot, decreased by treatment group (control > Endostar > CEF > combination therapy). The same was true for the mean BF, BV, MTT and PS, which decreased from the control group to the combination therapy group gradually. The mean MTT level increased in reverse order from the control to the combination therapy group. The difference between any 2 groups on these measures was statistically significant (P < 0.05). (2) There was moderate positive correlation between VEGF expression and BE, BV, or PS level (P < 0.05) and a negative correlation between VEGF expression and MTT level for all 4 groups (P < 0.05). Conclusion: Therefore, f-MSCT can be used as a non-invasive approach to evaluate the effect of anti-angiogenic therapy for implanted rabbit VX2 breast tumors.

  12. Accelerated magnetic resonance diffusion tensor imaging of the median nerve using simultaneous multi-slice echo planar imaging with blipped CAIPIRINHA

    Filli, Lukas; Kenkel, David; Boss, Andreas; Manoliu, Andrei; Andreisek, Gustav; Runge, Val M.; Guggenberger, Roman [University Hospital of Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Piccirelli, Marco [University Hospital of Zurich, Department of Neuroradiology, Zurich (Switzerland); Bhat, Himanshu [Siemens Medical Solutions USA Inc, Charlestown, MA (United States)

    2016-06-15

    To investigate the feasibility of MR diffusion tensor imaging (DTI) of the median nerve using simultaneous multi-slice echo planar imaging (EPI) with blipped CAIPIRINHA. After federal ethics board approval, MR imaging of the median nerves of eight healthy volunteers (mean age, 29.4 years; range, 25-32) was performed at 3 T using a 16-channel hand/wrist coil. An EPI sequence (b-value, 1,000 s/mm{sup 2}; 20 gradient directions) was acquired without acceleration as well as with twofold and threefold slice acceleration. Fractional anisotropy (FA), mean diffusivity (MD) and quality of nerve tractography (number of tracks, average track length, track homogeneity, anatomical accuracy) were compared between the acquisitions using multivariate ANOVA and the Kruskal-Wallis test. Acquisition time was 6:08 min for standard DTI, 3:38 min for twofold and 2:31 min for threefold acceleration. No differences were found regarding FA (standard DTI: 0.620 ± 0.058; twofold acceleration: 0.642 ± 0.058; threefold acceleration: 0.644 ± 0.061; p ≥ 0.217) and MD (standard DTI: 1.076 ± 0.080 mm{sup 2}/s; twofold acceleration: 1.016 ± 0.123 mm{sup 2}/s; threefold acceleration: 0.979 ± 0.153 mm{sup 2}/s; p ≥ 0.074). Twofold acceleration yielded similar tractography quality compared to standard DTI (p > 0.05). With threefold acceleration, however, average track length and track homogeneity decreased (p = 0.004-0.021). Accelerated DTI of the median nerve is feasible. Twofold acceleration yields similar results to standard DTI. (orig.)

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

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

  14. 多层螺旋CT核磁共振成像诊断腕关节损伤的临床应用研究%Clinical Analysis of Multi Slice Spiral CT Magnetic Resonance Imaging in Diagnosis of Wrist Joint Injury

    全宏卫

    2015-01-01

    目的:探讨多层螺旋CT(MSCT)与核磁共振成像(MRI)诊断腕关节损伤的价值。方法收集腕关节损伤患者112例,分别应用MSCT、MRI和联合诊断,比较三种诊断方法的诊断效能。结果骨折组中MRI对软骨损伤、骨挫伤和隐匿性骨折的检出率显著高于MSCT,而移位碎骨折片、关节脱位以及关节骨折的检出率显著低于MSCT(P<0.05);无骨折组中MRI检出隐匿性骨折、软骨损伤以及骨挫伤均显著高于MSCT,而关节脱位检出率显著低于MSCT(P<0.05)。结论 MSCT联合MRI诊断腕关节损伤具有较高的检出率以及诊断效能,值得推广应用。%Objective To evaluate multi-slice spiral CT (MSCT) and magnetic resonance imaging (MRI) of wrist injury diagnosis. Methods 112 cases of wrist injury, respectively by MSCT, MRI and combined diagnosis, diagnostic ef iciency comparison of three diagnostic methods. Results In the group of MRI fracture detection rate of cartilage, bone contusions and occult fractures were significantly higher than that of MSCT, and shift broken fracture and joint dislocation and the fracture of the joint detection rate was significantly lower than that of MSCT ( <0.05);without fracture in the group of MRI detected occult fracture, cartilage damage and bone contusion were significantly higher than MSCT, while the dislocation rate was significantly lower than that of MSCT ( <0.05). Conclusion MSCT combined with MRI in diagnosis of wrist joint injury detection rate and diagnosis ef iciency is high, it is worthy of popularization and application.

  15. MUSIC. a fast T2* - sensitive MRI technique with enhanced volume coverage

    A fast imaging method based on gradient-recalled echoes and echo time inter-leaved multi-slice excitation is presented. This method maintains the sensitivity of T2* by using a long echo time of at least 35 milliseconds. Bipolar gradients are used to shift the gradient echoes in order to ensure constant TE for each slab and prevent ghost-artefacts within the images caused by spin- or stimulated echoes. This method enhances the total imaging time of a conventional multi-slice gradient echo technique, while maintaining the high volume coverage. Thus, stimulated human cortical activation maps can be detected on standard clinical MR instruments at several planes within measuring times of a few seconds. The efficiency of the technique is demonstrated in the detection of temporary changes in T2* in functional MRI experiments of the human visual cortex at a magnetic field strength of 2 tesla. (author). 18 refs., 6 figs

  16. Assessment of volumetric bone mineral density of the femoral neck in postmenopausal women with and without vertebral fractures using quantitative multi-slice CT

    Sheng-yong WU; Hui-hui JIA; Didier HANS; Jing LAN; Li-ying WANG; Jing-xue LI; Yue-zeng CAI

    2009-01-01

    Objective: To demonstrate the validity and reliability of volumetric quantitative computed tomography (vQCT) with multi-slice computed tomography (MSCT) and dual energy X-ray absorptiometry (DXA) for hip bone mineral density (BMD) measurements, and to compare the differences between the two techniques in discriminating postmenopausal women with osteoporosis-related vertebral fractures from those without. Methods: Ninety subjects were enrolled and divided into three groups based on the BMD values of the lumbar spine and/or the femoral neck by DXA. Groups 1 and 2 consisted of postmenopausal women with BMD changes <-2SD, with and without radiographically confirmed vertebral fracture (n=11 and 33, respectively).Group 3 comprised normal controls with BMD changes ≥-1SD (n=46). Post-MSCT (GE, LightSpeed16) scan reconstructed images of the abdominal-pelvic region, 1.25 mm thick per slice, were processed by OsteoCAD software to calculate the following parameters: volumetric BMD values of trabecular bone (TRAB), cortical bone (CORT), and integral bone (INTGL) of the left femoral neck, femoral neck axis length (NAL), and minimum cross-section area (mCSA). DXA BMD measurements of the lumbar spine (AP-SPINE) and the left femoral neck (NECK) also were performed for each subject. Results: The values of all seven parameters were significantly lower in subjects of Groups 1 and 2 than in normal postmenopausal women (P<0.05, respectively).Comparing Groups 1 and 2, 3D-TRAB and 3D-INTGL were significantly lower in postmenopausal women with vertebral fracture(s) [(109.8±9.61) and (243.3±33.0) mg/cm3, respectively] than in those without [(148.9±7.47) and (285.4±17.8) mg/cm3,respectively] (P<0.05, respectively), but no significant differences were evident in AP-SPINE or NECK BMD. Conclusion: the femoral neck-derived volumetric BMD parameters using vQCT appeared better than the DXA-derived ones in discriminating osteoporotic postmenopausal women with vertebral fractures from

  17. Multi-slice spiral CT reconstruction in the diagnosis tracheal bronchus%多排螺旋CT重建技术诊断气管性支气管

    童三龙; 邓宏亮; 张凯; 王新正

    2014-01-01

    目的:探讨多排螺旋CT(MSCT)对气管性支气管的诊断及应用价值,认识先天性气管性支气管的临床意义。方法分析5例气管性支气管(TB)患者的MSCT薄层图像及多平面重组(MPR)、最小密度投影(MinIP)、容积再现(VR)及支气管虚拟内镜(VB)等多种后处理图像。结果5例气管性支气管均为右肺上叶尖段支气管发生在气管及右主支气管的右侧壁或右后壁,经多种后处理,均能清晰地显示气管性支气管的起源部位,有无狭窄及其他合并症情况。结论 MSCT无创、操作简单,可作为气管性支气管诊断的首选检查方法。%Objective To investigate the value of diagnosis and application in multi-slice spiral CT (MSCT) for diagnosing tracheal bronchus (TB), and recognize the clinical significance of tracheal bronchus(TB). Methods Ana-lyze the original and reconstructed MSCT images of 5 patients with TB, the reconstruction techniques included multi-planar reconstruction (MPR), minimum intensity projection (MinIP), volume rendering (VR), virtual bronchoscopy (VB). Results Five cases of tracheal bronchus occurred in the trachea or right main bronchus of the right side wall or the right posterior wall. Initiation site, stenosis, other complications of TB can be clearly displayed by various 3D recon-struction technology. Conclusion As a noninvasive and simple examination methods, MSCT should be the first choice in diagnosing TB.

  18. Comparison of myocardial perfusion SPECT with 64-slice multi-slice computed tomography angiography in cardiac screening of asymptomatic diabetic patients

    Lim, Il Han; Lee, Won Woo; Chang, Hyuck Jae; Choi, Sang II; Kim, Sang Eun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2007-07-01

    Asymptomatic diabetic patients may suffer silent ischemia. However, the question that what is the optimal screening tool for detection of cardiac disease in asymptomatic diabetic patients has not been addressed. We prospectively recruited diabetic patients who had not complained chest pain, and obtained myocardial perfusion SPECT (MPS) and cardiac CT angiography (CTA). We compared perfusion status on MPS with findings on CTA. A total of 110 diabetic patients (Age range 41-84, mean age 61.6{+-}7.74; gender, M: F 66:44) without cardiac symptom underwent both MPS and CTA. The MPS protocol was one-day single isotope study, adenosine stress Tc-99m MIBI/rest Tc-99m MIBI. CTA was conducted using 64-slice multi-slice CT (Brillance64, Philips Medical Systems). Perfusion status on MPS was assessed by summed-stress score (SSS) using 20-segment model, and SSS of {>=}4 was considered abnormal. Coronary stenosis of more than 50% luminal narrowing in CTA was considered significant, and coronary artery calcium scoring (CACS) was graded as: < or =10, 11-100, 101-400, or >400. MPS found abnormal perfusion in 11.8% (13/110) and CTA significant coronary stenosis in 20.9% (23/110). Five patients showed both abnormal perfusion and significant coronary stenosis. CACS (n=103 patients) were measured as; < or =10 in 45.6%, 11-100 in 28.1%, 101-400 in 19.4%, and >400 in 6.8%. The patient proportion of abnormal MPS in each CACS group were; 10.6% with < or = 10, 17.2% with 11-100, 5% with 101-400, and 0% with >400. The patient proportion of significant coronary stenosis on CTA in each CACS group were; 2.13% with < or =10, 27.6% with 11-100, 35% with 101-400, and 57.1% with >400. In asymptomatic diabetic patients, coronary stenosis by CTA showed correlation with coronary artery calcium scoring, but myocardial perfusion status by MPS did not. Long-term evaluation is essential for determination of prognostic significance of MPS and cardiac CTA.

  19. Multi-slice spiral CT of aortocoronary grafts and internal mammary artery bypasses: Assessment of bypasses and their anastomoses; Mehrzeilen-Spiral-CT von aortokoronaren Venenbypaessen und Mammaria-interna-Bypaessen: Beurteilung der Bypaesse und ihrer Anastomosen

    Froehner, S.; Wagner, M.; Schmitt, R.; Christopoulos, G.; Coblenz, G. [Inst. fuer Diagnostische und Interventionelle Radiologie, Herz- und Gefaessklinik GmbH, Bad Neustadt an der Saale (Germany); Brunn, J.; Mueller, M.; Kerber, S. [Fachbereich Kardiologie, Herz- und Gefaessklinik GmbH, Bad Neustadt an der Saale (Germany); Urbanski, P. [Klinik fuer Herzchirurgie, Herz- und Gefaessklinik GmbH, Bad Neustadt an der Saale (Germany)

    2002-07-01

    Objective: To assess aortocoronary grafts and internal mammary artery bypasses by means of EKG-triggered contrast-enhanced multi-slice spiral CT, and to evaluate the diagnostic accuracy of this new imaging modality. Material and methods: 59 patients with up to 5 aortocoronary grafts and/or internal mammary artery bypasses per patient were examined with regard to bypass morphology, the free passage, and the proximal as well as the distal anastomoses using multi-slice computed tomography. Axial source images were calculated by means of retrospective triggering at different diastolic delay times, and were postprocessed in several planes with the multiplanar volume reconstruction (MPVR) software. Results: On the pre-condition that data sets were acquired at sinus rhythm and at a heart rate lower than 65/min, aortocoronary grafts and internal mammary artery bypasses could be depicted in adequate diagnostic quality in about 80% of all cases with contrast-enhanced multi-slice spiral CT. Both, the free passage of the bypasses as well as the morphology of the proximal anastomoses were sufficiently assessed with multiplanar volume reconstruction (MPVR), whereas the distal anastomoses couldn't be depicted sufficiently in 20% of all cases. Conclusion: As a non-invasive method, contrast-enhanced and ECG-triggered multi-slice spiral computed tomography has gained diagnostic potential for the accurate visualization of aortocoronary grafts and the internal mammary artery bypasses. (orig.) [German] Ziel: Die vorliegende Arbeit stellt die Moeglichkeiten der kontrastmittelverstaerkten, EKG-getriggerten Mehrzeilen-Computertomographie in der Beurteilung von aortokoronaren Venenbypaessen und Mammaria-interna-Bypaessen dar. Material und Methode: Bei 59 Patienten mit 1 bis 5 aortokoronaren Venen-Bypaessen bzw. Mammaria-interna-Bypaessen wurden deren Morphologie, Durchgaengigkeit, die proximalen Anastomosen und die distalen Insertionsstellen mittels Mehrzeilen-Spiral-CT untersucht

  20. MRI of the regions of inner ear and cerebellopontine angle using a 3D T2-weighted turbo spin-echo sequence. Comparison with conventional 2D T2-weighted turbo spin-echo sequences and T1-weighted spin-echo sequences

    Purpose: To assess the value of a three-dimensional (3D) T2-weighted turbo spin-echo sequence (3D T2-TSE) in comparison to conventional two-dimensional (2D) T2-weighted TSE and unenhanced and enhanced T1-weighted spin-echo sequences (SE) in imaging anatomic structures and pathologic changes of the inner ear and cerebellopontine angle. Patients and methods: The inner ear and cerebellopotine angle were investigated by MRI in three healthy volunteers and 18 patients performing a 2D T2-weighted turbo spin-echo sequence and a 3D T2-TSE in the axial plane. In the patient study, 2D T1-weighted SE sequences both before and after the i.v. injection of gadopentate dimeglumine in both the axial and coronal plane were performed in addition. Results: Only the 3D T2-TSE enabled an accurate imaging of the anatomic structures. In cases of pathology, the 3D T2-TSE provided additional information to the performed 2D sequences. The combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted SE enabled the most accurate diagnosis in case of pathology. Conclusions: Accurate depiction of anatomic structures of the inner ear and cerebellopontine angle could be obtained by 3D T2-TSE only. The most accurate diagnosis in cases of pathology was provided by the combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted spin-echo sequences. (orig.)

  1. Comparison of two single-breath-held 3-D acquisitions with multi-breath-held 2-D cine steady-state free precession MRI acquisition in children with single ventricles

    Atweh, Lamya A.; Dodd, Nicholas A.; Krishnamurthy, Ramkumar; Chu, Zili D. [Texas Children' s Hospital, EB Singleton Department of Pediatric Radiology, Cardiovascular Imaging, Houston, TX (United States); Pednekar, Amol [Philips Healthcare, Houston, TX (United States); Krishnamurthy, Rajesh [Texas Children' s Hospital, EB Singleton Department of Pediatric Radiology, Cardiovascular Imaging, Houston, TX (United States); Baylor College of Medicine, Department of Radiology, Houston, TX (United States); Baylor College of Medicine, Department of Pediatrics, Houston, TX (United States)

    2016-05-15

    Breath-held two-dimensional balanced steady-state free precession cine acquisition (2-D breath-held SSFP), accelerated with parallel imaging, is the method of choice for evaluating ventricular function due to its superior blood-to-myocardial contrast, edge definition and high intrinsic signal-to-noise ratio throughout the cardiac cycle. The purpose of this study is to qualitatively and quantitatively compare the two different single-breath-hold 3-D cine SSFP acquisitions using 1) multidirectional sensitivity encoding (SENSE) acceleration factors (3-D multiple SENSE SSFP), and 2) k-t broad-use linear acceleration speed-up technique (3-D k-t SSFP) with the conventional 2-D breath-held SSFP in non-sedated asymptomatic volunteers and children with single ventricle congenital heart disease. Our prospective study was performed on 30 non-sedated subjects (9 healthy volunteers and 21 functional single ventricle patients), ages 12.5 +/- 2.8 years. Two-dimensional breath-held SSFP with SENSE acceleration factor of 2, eight-fold accelerated 3-D k-t SSFP, and 3-D multiple SENSE SSFP with total parallel imaging factor of 4 were performed to evaluate ventricular volumes and mass in the short-axis orientation. Image quality scores (blood myocardial contrast, edge definition and interslice alignment) and volumetric analysis (end systolic volume, end diastolic volume and ejection fraction) were performed on the data sets by experienced users. Paired t-test was performed to compare each of the 3-D k-t SSFP and 3-D multiple SENSE SSFP clinical scores against 2-D breath-held SSFP. Bland-Altman analysis was performed on left ventricle (LV) and single ventricle volumetry. Interobserver and intraobserver variability in volumetric measurements were determined using intraclass coefficients. The clinical scores were highest for the 2-D breath-held SSFP images. Between the two 3-D sequences, 3-D multiple SENSE SSFP performed better than 3-D k-t SSFP. Bland-Altman analysis for volumes

  2. 2D solar modeling

    Ventura, P; Li, L; Sofia, S; Basu, S; Demarque, P

    2009-01-01

    Understanding the reasons of the cyclic variation of the total solar irradiance is one of the most challenging targets of modern astrophysics. These studies prove to be essential also for a more climatologic issue, associated to the global warming. Any attempt to determine the solar components of this phenomenon must include the effects of the magnetic field, whose strength and shape in the solar interior are far from being completely known. Modelling the presence and the effects of a magnetic field requires a 2D approach, since the assumption of radial symmetry is too limiting for this topic. We present the structure of a 2D evolution code that was purposely designed for this scope; rotation, magnetic field and turbulence can be taken into account. Some preliminary results are presented and commented.

  3. MSCT重组技术对气管破裂的诊断价值%Multi-slice CT and advanced reconstruction techniques in the diagnosis of tracheal rupture

    杨鸿; 杨文; 蒋洪春; 彭湘晖; 曹林德

    2012-01-01

    Objective:To assess the value of multi slice CT (MSCT) with reconstruction techniques in the diagnosis of tracheal rupture. Methods: 128 slice spiral CT (MSCT) scanning was performed in 7 patients with tracheal rupture caused by severe trauma to the neck and thorax,iatrogenic injury and spontaneous tracheal rupture. The images of multipla nar reconstruction (MPR) ,CT virtual endoscopy (CTVE) were obtained on a postprocessing workstation. Results: CT ap pearances of tracheal rupture included defect in trachea with deep cervical air or air tracking into the mediastinum. MPR clearly displayed the shape and size of tracheal defect,the distances between the tracheal defect to some important anatomic landmarks such as tracheal carina, epiglottis and superior border of the manubrium. CTVE showed the tracheal defects in the 5 patients with trauma to the neck and thorax and spontaneous tracheal ruptures. However,the image of CTVE was a little blurred than MPR. Color coded volume rendered images provided realistic 3D views of air leak distribution of the tra cheal rupture. Conclusion: MSCT with reconstruction techniques play an important role in the diagnosis and treatment of tra cheal rupture.%目的:探讨MSCT重组技术对气管破裂的诊断及临床应用价值.方法:回顾性分析7例气管破裂患者的CT资料,病因分别为颈胸部严重外伤、医源性损伤、自发性因素.采用128层螺旋CT对7例患者行颈胸部平扫,原始数据行减薄重组,将减薄重组后的图像传输到工作站进行多平面重组及CT仿真内窥镜(CTVE)观察.结果:气管破口以及溢出的气体均表现为低密度影,气管壁连续性中断,MPR重组可以完整显示破裂口形态和大小、距气管隆突、会厌或胸骨柄上缘等重要解剖标志的距离;2例严重患者在双侧颜面部、颈部、颞下窝、咽旁组织间隙、前后胸壁皮下、纵隔内均有广泛分布的低密度气影;最轻的1例仅见裂口附近的后纵隔内

  4. Vertical 2D Heterostructures

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  5. 多层螺旋CT与核磁共振成像联合诊断腕关节损伤的探析%Multi-slice spiral CT combined with magnetic resonance imaging in diagnose of wrist joint injury

    郭侨阁; 王顺利; 牛军杰; 刘彦; 唐楠; 周龙

    2015-01-01

    Objective To explore significance of multi-slice spiral CT combined with magnetic resonance imaging in the diagnose of wrist joint injury.Methods 168 patients with wrist joint injury admitted into our hospital from January,2012 to September,2014 were investigated.Their clinical data were analyzed.According the different examination methods,the patients were randomly divided into three groups,56 cases for each group.These 3 groups were given multi-slice spiral CT examination,magnetic resonance imaging examination,and multi-slice spiral CT combined with magnetic resonance imaging examination,respectively.The diagnosis situations and the advantages of different examination methods of the three groups were analyzed.Results The detection rate of multi-slice spiral CT was 73.21%,that of magnetic resonance imaging 75.00%,and that of the combination group 96.43%.The statistical analysis showed that there were no significant differences (P> 0.05).However,the detection rate of the combination group was significantly higher than those multi-slice spiral CT and magnetic resonance imaging (P <0.05);The detection rate of the combination of multi-slice spiral CT and magnetic resonance imaging was significantly higher than that of just one of these two examination methods(P <0.05).Conclusions Multi-slice spiral CT combined with magnetic resonance imaging in the diagnosis of wrist joint injury is most effective.It synthesizes the advantages of the two examination methods,improves the detection rate,and makes the specific injury situation clear.It's worth being clinically generalized.%目的 探究采用多层螺旋CT与核磁共振成像联合诊断腕关节损伤的情况.方法 调查研究我院在2012年1月至2014年9月间收治的168例腕关节损伤患者,分析其临床资料,根据检查方法的不同,将本组患者随机分成三组,各56例,分别给予多层螺旋CT检查、核磁共振成像检查和多层螺旋CT联合核磁共振成像检查.分析

  6. Activated sludge model No. 2d, ASM2d

    Henze, M.

    1999-01-01

    The Activated Sludge Model No. 2d (ASM2d) presents a model for biological phosphorus removal with simultaneous nitrification-denitrification in activated sludge systems. ASM2d is based on ASM2 and is expanded to include the denitrifying activity of the phosphorus accumulating organisms (PAOs...

  7. Genetic association of glutathione peroxidase-1 with coronary artery calcification in type 2 diabetes: a case control study with multi-slice computed tomography

    Fujimoto Kei; Nishioka Makiko; Miyashita Yumi; Hiki Yoshito; Sasaki Takashi; Nishimura Rimei; Nemoto Masami; Sakuma Toru; Ohashi Toya; Fukuda Kunihiko; Eto Yoshikatsu; Tajima Naoko

    2007-01-01

    Abstract Background Although oxidative stress by accumulation of reactive oxygen species (ROS) in diabetes has become evident, it remains unclear what genes, involved in redox balance, would determine susceptibility for development of atherosclerosis in diabetes. This study evaluated the effect of genetic polymorphism of enzymes producing or responsible for reducing ROS on coronary artery calcification in type 2 diabetes (T2D). Methods An index for coronary-arteriosclerosis, coronary artery c...

  8. The relationship between MRI and PET changes and cognitive disturbances in MS

    Sørensen, Per Soelberg; Jønsson, Agnete; Kahr Mathiesen, Henrik;

    2006-01-01

    spectroscopy (MRS) performed with multi-slice echo planar spectroscopic imaging (EPSI) and PET measurements of brain metabolism as the cortical cerebral metabolic rate of glucose are imaging methods that are able to provide information on axonal loss or dysfunction in both MS lesions and in NAWM and cortical...... brain including abnormalities in normal appearing white matter (NAWM) and cortical grey matter, which is undetected with conventional magnetic resonance imaging (MRI). Hence, imaging techniques that embrace such abnormalities are needed to achieve better correlation with cognitive dysfunction. MR...

  9. 多层螺旋CT后处理技术在膝关节交叉韧带MR扫描方式中的应用%Application of multi-slice spiral CT images post-processing in MR scanning mode for the cruciate ligament of knee joint

    严由伦; 李荣; 董燕; 余建国

    2013-01-01

    locating line was parallel with the inner side of the lateral condyle, or incline inward 10 degree with sagittal plane. On the coronal plane, the locating line was parallel with the line which was connected by the intcrcon-dylar eminence and intcrcondylar fossa, or inclines outward 15 degree with lower limb long axis) and the oblique coronal planc( using transverse and sagittal plane as a locating line. On the transverse plane, the locating line was parallel with the line which was connected by the posterior margin between inner condyle and lateral condyle. On the sagittal plane, the locating line was parallel with the direction of anterior cruciate ligament, or incline 35 - 40 degree with conronal) were reconstructed by anatomy course of the knee joint cruciate ligament. Finally, the cruciate ligament images of knee joint was estimated, and the locating method for oblique sagittal plane and the oblique coronal plane were used in MR scanning. Results The cruciate ligament images of knee joint for multi-slice spiral CT and magnetic resonance image had same result statistically. There was no difference between MSCT and MRI. The display rate of the anterior cruciate ligament on the oblique coronal plane were 100%, and on the oblique sagittal plane 98% , the display rates of the posterior cruciate ligament on the sagittal plane was 100% on MR imaging. Conclusion The multi-slice spiral CT had given instructions to assist optimal orientation of MR imaging the cruciate ligament of knee joint, which is simple and easy operation.

  10. 多层螺旋CT尿路成像在上尿路疾病中的应用%Application of Multi-slice Spiral CT Urography in Diagnosis of Upper Ureteric Diseases

    李建勇; 程树林; 陈双全; 朱平宇; 廖波

    2013-01-01

    目的探讨多层螺旋CT尿路成像(CTU)在上尿路疾病中的临床应用价值。方法对41例经B超或IVP检查显示上尿路疾病患者行螺旋 CT扫描,并行三维重建,将诊断与手术结果进行对照。结果41例中输尿管狭窄20例,肾盂及输尿管肿瘤10例,输尿管结石8例,结核3例。CTU均立体直观地显示病变形态及其与周围组织的关系,诊断与最终手术结果均相符。结论 CTU是一种安全有效的非侵袭性的影像学检查方法,对上尿路疾病的诊断具有极高价值。%Objective To assess the diagnostic value of multi slice spiral CT urography (CTU) in patients with upper urinary tract diseases. Methods 41 patients with upper urinary tract diseases confirmed by B-ultrasound or IVP performed multi slice spiral CT urography (CTU) scan and the three dimensional reconstructions. The imaging findings were checked with post operative pathological findings. Results In the 41 cases , congenital stricture in ureteropelvic junction or ureterovesical orifice were found in 20 cases ,21 patients were diagnosed as pyeloureter neoplasm (10 cases) , ureter negative stone (8 cases),tuberculosis of ureter (3 cases).CTU provided high resolution images of the pelvis and ureter tract in al patients. All the cases were confirmed by operation.Conclusion CTU is a safe, highly efficient and noninvasive method, it plays important role in the diagnosis of urinary diseases.

  11. Lectures on 2D gravity and 2D string theory

    This report the following topics: loops and states in conformal field theory; brief review of the Liouville theory; 2D Euclidean quantum gravity I: path integral approach; 2D Euclidean quantum gravity II: canonical approach; states in 2D string theory; matrix model technology I: method of orthogonal polynomials; matrix model technology II: loops on the lattice; matrix model technology III: free fermions from the lattice; loops and states in matrix model quantum gravity; loops and states in the C=1 matrix model; 6V model fermi sea dynamics and collective field theory; and string scattering in two spacetime dimensions

  12. 2D-hahmoanimaation toteuttamistekniikat

    Smolander, Aku

    2009-01-01

    Opinnäytetyössä tutkitaan erilaisia 2D-hahmoanimaation toteuttamistekniikoita. Aluksi luodaan yleiskatsaus animoinnin historiaan ja tekniikoihin piirtämisestä mallintamiseen. Alkukatsauksen jälkeen tutkitaan 2D-hahmon suunnittelua ja liikkeitä koskevia sääntöjä. Hahmoanimaation liikkeissä huomionarvoisia asioita ovat muun muassa ajastus, liioittelu, ennakointi ja painovoima. Seuraavaksi perehdytään itse 2D-hahmoanimaation toteuttamistekniikoihin. Tavoitteena on selvittää, tutkia ja vertailla ...

  13. Application of Multi-slice Spiral Computed Tomography To Diagnose Hyoid Fracture%多层螺旋CT对舌骨骨折的临床应用价值

    周建中; 石士奎; 季立平

    2008-01-01

    目的 探讨多层螺旋CT(multi-slice spiral computed tomography,MSCT)对舌骨骨折的诊断价值,提高对舌骨骨折临床重要性的认识.方法 回顾性分析6例舌骨骨折的MSCT及临床表现特点.结果 本组6例舌骨骨折中,舌骨大角骨折1例,舌骨体部骨折1例,舌骨大角与体部连接处骨折4例,其中舌骨大角与体部连接处骨折MSCT仅表现为连接处间隙增宽、错位,未见明确骨皮质连续性中断征象.结论 MSCT对舌骨骨折具有重要的诊断价值,对可疑舌骨骨折患者应行MSCT检查.

  14. 多层螺旋CT对肝外梗阻性黄疸的诊断价值%Diagnostic value of multi-slice spiral CT in extrahepatic obstructive jaundice

    王小仁; 张云; 蔡顺达

    2015-01-01

    Objective To explore the diagnostic value of multi-slice spiral CT in extrahepatic obstructive jaundice.Methods MSCT findings in 12 cases ofextrahepatic obstructive jaundice confirmed by the surgery and clinic were retrospectively analyzed.Results Among 12 cases,10 cases were subjected to anhanced scanning;Among all cases,6 cases of bile duct carcinoma,3 cases of carcinoma of head of pancreas, 3 cases of bile duct stones.Conclusion CT scan can clearly without obstruction, determining the site of obstruction,further qualitative diagnosis.%目的:探讨多层螺旋CT对梗阻性黄疸的诊断价值。方法:回顾性分析由手术和临床证实的12例患者的CT资料。结果:12例患者中,10例行CT平扫加增强扫描;12例患者中胆管癌6例,胰头癌3例,胆管结石3例。结论:CT检查可明确有无梗阻的存在,确定梗阻部位,进一步行定性诊断。

  15. Optoelectronics with 2D semiconductors

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  16. Accretion Disks Phase Transitions 2-D or not 2-D?

    Abramowicz, M A; Igumenshchev, I V; Abramowicz, Marek Artur; Bjornsson, Gunnlaugur; Igumenshchev, Igor V.

    2000-01-01

    We argue that the proper way to treat thin-thick accretion-disk transitions should take into account the 2-D nature of the problem. We illustrate the physical inconsistency of the 1-D vertically integrated approach by discussing a particular example of the convective transport of energy.

  17. Comparative study on the clinical value between multi slice spiral CT urography and intravenous pyelography%多层螺旋CT尿路成像与静脉肾盂造影的临床价值对比研究

    傅其添; 林忠伟; 陈恩明

    2014-01-01

    目的:通过对比多层螺旋 CT 尿路成像(MDCTU)和静脉肾盂造影(IVP)对泌尿系统疾病检出和诊断准确率,探讨MDCTU检查对泌尿系统疾病的临床应用价值和对IVP的优良替代性。方法:2011-2013年收治泌尿系疾病患者75例,均接受MDCTU和IVP检查。比较两种检查方法对泌尿系统疾病的检出及诊断差异,并与手术病理或临床随访结果对照。结果:经手术病理或临床随访证实,共发现结石39例,肿瘤14例,炎症8例,肾囊肿8例,创伤3例,先天性畸形3例。75例患者中MDCTU和IVP检查诊断检出率分别为96%(72/75)、52%(42/75),两者差异有统计学意义(P<0.05)。结论:CTU能够提供IVP所无法具备的丰富的诊断信息,对泌尿系统疾病检出、定性、周边侵犯等方面诊断明显优于IVP,完全可代替IVP而成为临床常规检查。%Objective:By comparing the detection rate and the accurate rate of diagnosis of multi slice spiral CT urography(MDCTU) and multi-slice spiral CT imaging and urinary detection(MDCTU) and intravenous pyelography(IVP) in urinary system diseases,to explore the clinical application value and excellent alternative to IVP of MDCTU examination in urinary system disease.Results:75 cases with urinary tract diseases were selected from 2011 to 2013.They were given MDCTU and IVP examination.We compared the detection rate and the accurate rate of the two check modes,and compared it with operation and pathology or clinical follow-up results.Results:Proved by operation and pathology or clinical follow-up,39 cases were calculi;14 cases were tumor;8 cases were inflammation;8 cases were renal cysts;3 cases were trauma;3 cases were congenital malformation.In 75 cases,the detection rate of MDCTU and IVP were 96% (72/75) and 52% (42/75),and the difference was statistically significant(P<0.05).Conclusion:CTU can provide abundant diagnostic information which IVP cannot be made.The diagnosis of urinary

  18. Clinical value of multi-slice helical CT angiography in diagnosis of cerebral vascular diseases%MSCTA在脑血管性疾病诊断中的应用价值

    宁殿秀; 李智勇; 王克礼

    2006-01-01

    Objective: To evaluate the clinical value of multi-slice helical CT angiography (MSCTA) in diagnosis of cerebral vascular diseases.Methods: 52 patients with cerebral vascular diseases were examined with GE Light Speed 4-slice and 16-slice helical CT.Pitch: 0.5-3,slice thickness: 0.625-1.25 mm,adult injection dosage: 90-100 mL,children injection dosage: 2 mL/kg,injection rate: 2.5-4.0 mL/s,delay time: 15-22 s.Intelligent track scan (Smart prep Rx) were adopted in parts of these cases.Three-dimensional cerebral vascular images were processed at ADW 3.1 and ADW 4.2 workstation.Results:MSCTA could clearly display spacious anatomic details of cerebral aneurysm,including its origin,size,neck width,and trend etc.MSCTA results of 19 cases were consistent with those of operations.The diameter of the smallest cerebral aneurysm shown in our research was about 3 mm.As a non-invasive examination,MSCTA could also be applied in post-operational evaluation of cerebral aneurysm by observing the location of silver clip and the distant vessels.Besides,MSCTA could be used to diagnose arteriovenous malformation and moyamoya disease.Of all the three-dimentional imaging methods,volume rendering (VR)is the best means to display the cerebral vascular diseases.Conclusion: As a non-invasive examination,MSCTA plays an important role in detection,pre-operational and post-operational evaluation of cerebral vascular diseases.

  19. SES2D user's manual

    SES2D is an interactive graphics code designed to generate plots of equation of state data from the Los Alamos National Laboratory Group T-4 computer libraries. This manual discusses the capabilities of the code. It describes the prompts and commands and illustrates their use with a sample run

  20. 2D-Oide effect

    Blanco, O R; Bambade, P

    2015-01-01

    The Oide effect considers the synchrotron radiation in the final focusing quadrupole and it sets a lower limit on the vertical beam size at the Interaction Point, particularly relevant for high energy linear colliders. The theory of the Oide effect was derived considering only the radiation in the focusing plane of the magnet. This article addresses the theoretical calculation of the radiation effect on the beam size consider- ing both focusing and defocusing planes of the quadrupole, refered to as 2D-Oide. The CLIC 3 TeV final quadrupole (QD0) and beam parameters are used to compare the theoretical results from the Oide effect and the 2D-Oide effect with particle tracking in PLACET. The 2D-oide demonstrates to be important as it increases by 17% the contribution to the beam size. Further insight into the aberrations induced by the synchrotron radiation opens the possibility to partially correct the 2D-Oide effect with octupole magn

  1. Virtual colonoscopy by multi-slice CT

    Objective: To evaluate the usefulness of VC with MSCT and to determine the sensitivity (Se) and specificity (Sp) of this method in comparison with conventional colonoscopy (CC). Method and Materials: Thirty patients were studied with MSCT and CC. CTs were performed with a multislice CT scanner, with slices of 2,5 mm thickness, 1,3 mm reconstruction interval, 50 mAs, 120 Kv. The mean acquisition time was 25 seconds. Findings were divided in normal and pathologic. The latter was subdivided according to the diameter of the lesions: 2a) 9 mm. Results: The Se and Sp was in 2a) 82% and 78%; in 2b) 100% and 93%; and in 2c) 100% and 100% respectively. Conclusion: VC with MSCT showed high Se and Sp for the detection of elevated lesions. Its fast way of acquisition allows better patient tolerance and better resolution without respiratory artifacts. (author)

  2. Chest MRI

    Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI ... healthy enough to filter the contrast. During the MRI, the person who operates the machine will watch ...

  3. MRI and low back pain

    Backache - MRI; Low back pain - MRI; Lumbar pain - MRI; Back strain - MRI; Lumbar radiculopathy - MRI; Herniated intervertebral disk - MRI; Prolapsed intervertebral disk - MRI; Slipped disk - MRI; Ruptured ...

  4. Analysis about Inlfuencing Factors of Image Quality of Coronary Angiography with Multi-Slice CT%MSCT冠状动脉成像质量的影响因素分析

    赵坤; 邵广瑞; 王勇; 侯代伦

    2014-01-01

    目的:分析64层螺旋CT冠状动脉扫描中影响成像质量的各种因素。方法对89例怀疑冠心病或冠心病复查患者进行64层螺旋CT冠状动脉检查,回顾性分析成像质量,探讨心率及心率波动对冠脉成像质量的影响,pitch值与心率的关系,替代(override)功能的应用价值,从而优化扫描参数。结果心率及心率波动与冠脉成像质量成负相关;心率与扫描/重建方式及pitch值存在相互对应关系;心率替代功能的合理使用可以提高CT冠状动脉的成像质量。结论通过控制心率及心率波动,选择心率替代功能,采取适当的扇区扫描/重建模式可以提高图像质量和冠状动脉诊断的可靠性。%Objective To analyze the inlfuencing factors of image quality of coronary angiography with 64-slice CT.Methods Eighty-nine patients with known or suspected CAD underwent CT coronary angiography using 64 multi-slice CT. The image quality in those cases was analyzed retrospectively to evaluate the influence of heart rate, fluctuation of heart rate during the scanning. The relationship between heart rate and the value of pitch was analyzed, and the application value of the override function was discussed.Results① The patient’s heart rate and lfuctuation were negatively related to the coronary image quality.② There was corresponding relationship between the value of pitch and segment scan/reconstruction mode according to the heart rate.③ Correct use of override function could improve the image quality of coronary.Conclusion The appropriate control of heart rate and lfuctuation, the correct use of override function, and the corresponding selection of segment scan/reconstruction mode according to the heart rate could improve the image quality and reliability of coronary angiography.

  5. 2D-animaatiotuotannon optimointi

    Saturo, Reetta

    2015-01-01

    Tämän opinnäytetyön tavoitteena on tutkia 2D-animaatiotuotannon optimoinnin mahdollisuuksia tiukan tuotantoaikataulun vaatimuksissa. Tutkielmassa tarkastellaan kahta asiakasprojektia, jotka on toteutettu pienellä tuotantotiimillä. Työkaluna animaatioissa on käytetty pääosin Adoben After Effects -ohjelmistoa. Tutkielman alussa esitellään animaatiotuotannot, joiden tuloksena syntyi kaksi lyhyttä mainoselokuvaa. Sen jälkeen käydään läpi animaatioelokuvan tuotantoprosessia vaiheittain ja tark...

  6. Head First 2D Geometry

    Fallow), Stray

    2009-01-01

    Having trouble with geometry? Do Pi, The Pythagorean Theorem, and angle calculations just make your head spin? Relax. With Head First 2D Geometry, you'll master everything from triangles, quads and polygons to the time-saving secrets of similar and congruent angles -- and it'll be quick, painless, and fun. Through entertaining stories and practical examples from the world around you, this book takes you beyond boring problems. You'll actually use what you learn to make real-life decisions, like using angles and parallel lines to crack a mysterious CSI case. Put geometry to work for you, and

  7. 不同影像学方法对胰腺癌T、N、M分期及可切除性的评估%Prospective evaluation of ultrasonography, multi-slice spiral CT, endoscopic ultrasonography, and magnetic resonance imaging in assessment of TNM staging and assessment of resectibility in pancreatic carcinoma

    田艳涛; 曲辉; 赵平; 王成锋; 单毅; 赵东兵; 王贵齐; 赵心明; 欧阳汉; 郝玉芝; 孙跃民

    2008-01-01

    目的 前瞻性评估超声(US)、多层螺旋CT(MSCT)、内镜超声(EUS)和核磁共振(MRI)在胰腺癌T、N、M分期及可切除性的预测价值.方法 对68例胰腺癌分别进行超声(US)、螺旋CT(MSCT)、核磁共振(MRI)、超声内镜(EUS)检查,评估其在T、N、M分期和可切除性与手术病理结果比较及临床意义.结果 EUS对肿瘤大小的独立预测效果最好,最大径回归系数和最小径回归系数分别为1.025(P=0.043)和0.987(P<0.0001);在对淋巴结转移的评估中,EUS具有最高的敏感性(75.0%)、准确性(87.5%)和阴性预测价值(91.7%),单元Logistic回归显示与外科发现有显著相关性(OR值:33.00,95%CI:7.18~151.77 P<0.0001),且多元Logistic回归分析证实EUS具独立预测价值(OR值:34.50,95%CI:6.54~182.09,P<0.0001).MSCT评估远处转移具最高敏感性88.9%,其对胰腺癌术前TNM分期准确率最高,为61.8%.4种方法对胰腺癌可切除性的判断均与手术结果具有相关性,但多元回归分析尚无一种影像学检查具有独立预测价值.结论 MSCT对胰腺癌的TNM分期准确性最高,EUS评估肿瘤大小和淋巴结转移效果最好,对胰腺癌的术前评估尚需要两种以上的方法联合应用.%Objective To evaluate prospectively the efficacy and clinical significance of ultrasonography(US), multi-slice spiral CT (MSCT) , magnetic resonance imaging (MRI) , and endoscopic ultrasonography (EUS) in assessment of the TNM staging and resectibility of pancreatic carcinoma. Methods Consecutive 68 patients with pancreatic carcinoma underwent US, MSCT, MRI, and EUS to assess their efficacies in assessment of the size of carcinoma, lymph node metastasis, and distant metastasis. The results of theses imaging techniques were compared with the surgical and pathological findings. Results EUS was the most precise technique in evaluating the T staging of pancreatic carcinoma with the coefficients of regression of maximum and minimum radiuses of 1. 025 (P=0

  8. 2D SIMPLIFIED SERVO VALVE

    2003-01-01

    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  9. Personalized 2D color maps

    Waldin, Nicholas

    2016-06-24

    2D color maps are often used to visually encode complex data characteristics such as heat or height. The comprehension of color maps in visualization is affected by the display (e.g., a monitor) and the perceptual abilities of the viewer. In this paper we present a novel method to measure a user\\'s ability to distinguish colors of a two-dimensional color map on a given monitor. We show how to adapt the color map to the user and display to optimally compensate for the measured deficiencies. Furthermore, we improve user acceptance of the calibration procedure by transforming the calibration into a game. The user has to sort colors along a line in a 3D color space in a competitive fashion. The errors the user makes in sorting these lines are used to adapt the color map to his perceptual capabilities.

  10. 多层螺旋CT在胃肠间质瘤定位和定性诊断中的价值%Values of multi-slice CT in differential diagnosis of gastrointestinal stromal tumors

    卢文彬

    2014-01-01

    目的:探讨多层螺旋CT在胃肠道间质瘤( GIST)定位和定性中的诊断价值。方法:对本院30例手术病理证实为胃肠间质瘤的患者的CT影像特点进行回顾性分析。均行16层螺旋CT平扫和增强扫描,探讨病灶位置、大小及有无坏死等情况。结果:胃肠道间质瘤单发患者21例、多发9例;其中17例肿瘤部位在胃部、8例位于小肠、5例位于直肠。19例向腔内外同时生长、8例向腔外生长、3例向腔内生长。恶性GIST 强化不均匀,可有邻近脏器侵犯。16层螺旋CT定性准确率为83.3%(25/30)、定位准确率90.0%(27/30)。结论:CT 增强扫描有利于GIST的定位诊断及对肿瘤良恶性质的判断,能准确显示肿瘤的部位、形态、大小,是目前检查GIST的重要方法之一。%Objective:To investigate the diagnosis values of multi-slice CT ( MSCT ) on diagnosis of gastrointestinal stromal tumors ( GIST) . Methods:The CT characteristics of 30 tumors of pathological confirmed GIST in our hospital were retrospectively analyzed. All patients were scanned with unenhanced and enhanced 16-slice CT, and then the location, size and necrosis of lesions were analyzed. Results:Among all 30 cases, single lesions of GIST were 21 cases, and motile lesions of GIST were 9 cases. And 17 cases located at stomach, 8 cases at small intestine, and 5 cases at rectum. There were 19 cases simultaneously inside and outside the chamber, 8 cases of external cavity growth, and 3 cases of intracavity growth. The malignant GIST exhibited inhomogeneous enhancement and invasion to adjacent organs. Accuracy of 16-slice CT diagnosis for qualitative analysis was 83. 3% ( 25/30 ) and for location was 90. 0% ( 27/30 ) of GISTs. Conclusion: CT enhanced scan benefits the localization diagnosis of GIST and the determination of benign or malignant tumors. It could accurately show the location, form and size of tumors, which is one of the significant methods to examine

  11. 多层螺旋CT对健康成人肾周间隙及肾筋膜的测量%Anatomy of the perirenal space and renal fascia:a multi-slice spiral CT observation

    王娜; 刘荣波; 孔维芳

    2011-01-01

    Objective: To measure the renal fascia and evaluate the anatomy of perirenal space and its communications sand boundarics with multi-slice spiral CT (MSCT). Methods : MSCT scanning was performed in 97 normal subjects , and the multiplanar reconstruction (MPR) images of perirenal space and its anatomical communications were obtained on a postprocessing workstation. The shapc, size and anatomical communications of the perirenal space were observed and measured.Results : Between the upper and lower pole of kidney,the detection rate of renal fascia was 100%. It was easier to visualize the renal fascia on MPR images than those on transverse CT images. The thickness of the left and right renal fascia was (0.13+0. 02)cm and (0. 12+0. 02)cm, respectively. No significant difference in renal fascia thickness was found between different gender and age groups (all P>0.05). Different types of adhesion and anatomical communication of renal fascia were distinctly visualized on MSCT images. Conclusions : MSCT and MPR images could clearly visualize the morphologic features and anatomical communication of the perirenal space, which may be helpful in making diagnostic decisions.%目的:通过多层螺旋CT对正常成人肾筋膜和肾周闯隙的观察和测量.探讨多层螺旋CT显示肾筋膜的附着及通连情况.方法:搜集在我院接受腹部CT增强扫描检查的健康成人资料97例,采用多层螺旋CT扫描对肾周间隙行多平面三维重组,测定肾筋膜的厚度,并观察肾筋膜的显示率以及肾筋膜向上和向下的通连情况.结果:肾筋膜在肾脏上、下极之间的显示率为100%,且双侧肾筋膜在MPR图像上的显示率大于轴面图像.左、右侧肾筋膜厚度分别为(0.13±0.02)cm和(0.12±0.02)cm,不同性别及年龄组别间筋膜厚度差异无统计学意义(P>0.05).多层螺旋CT发现肾筋膜的附着及肾周间隙的通连情况具有不同类型:①双侧肾前、后筋膜向下融合,融

  12. MSCT尿路成像技术在泌尿系统疾病诊断中的价值%The value of multi-slice CT urography in diagnosis of urinary tract diseases

    沈纪芳; 朱玉春; 王建良

    2012-01-01

    目的 探讨多层螺旋CT(MSCT)尿路成像技术在泌尿系统疾病诊断中的价值.方法 对80例泌尿系统疾病患者行CT尿路成像检查,通过常规平扫、动脉期、静脉期、延迟期图像数据进行多平面重组法(MPR)、曲面重组法(CPR)、最大密度投影法(MIP)和容积成像法(VR)进行三维重组,对影像图像进行分析.结果 CT尿路成像技术能够清晰显示泌尿系统的整体结构和输尿管走行和周围组织的关系.80例中,泌尿系统结石46例,输尿管癌4例,肾盂癌1例,先天性发育畸形5例,输尿管炎性狭窄9例,输尿管瘘1例,输尿管息肉1例,盆腔内恶性肿瘤累及或术后侵犯7例,正常6例.MSCT尿路成像诊断特异性为i00%(80/80),诊断准确率为95%(76/80);1例输尿管息肉和3例炎性狭窄误诊为输尿管癌,误诊率为5%(4/80).结论 MSCT尿路成像图像清晰直观,可以作为早期确诊泌尿系统疾病的有效影像检查方法.%Objective To investigate the diagnostic value of multi-slice CT(MSCT) urography in urinary tract diseases. Methods CT urography was performed in 80 cases with urinary tract diseases. The multiplanar reconstruction (MPR), maximum intensity recontruction (MIP), cured planar reformation(CPR) and volume rendering(VR) were reconstructed based on the data extracted by conventional plain scan,arteral phase, venous phase and lag period scaa Results MSCT urography provided clear three dimensional images of the whole kidney, ureter and urinary bladder, the entire and partial structure,shape and relation with the tissues surrounding them. Of 80 cases, the diagnosis of urinary calculus was confermed in 46 cases, ureteral carcinoma in 4 cases, renal pelvic carcinoma in 1 case,urinary congenital malformation in 5 cases, urinary inflammation in 9 cases, ureteral fistula in 1 case,ureteral polyp in 1 case, ureter invaded by palvic magligant mass in 7 cases, and normal in 6 cases. In the diagnosis of urinary tract diseases, the

  13. Learn Unity for 2D game development

    Thorn, Alan

    2013-01-01

    The only Unity book specifically covering 2D game development Written by Alan Thorn, experience game developer and author of seven books on game programming Hands-on examples of all major aspects of 2D game development using Unity

  14. MRI Scans

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  15. Surface modelling for 2D imagery

    Lieng, Henrik

    2014-01-01

    Vector graphics provides powerful tools for drawing scalable 2D imagery. With the rise of mobile computers, of different types of displays and image resolutions, vector graphics is receiving an increasing amount of attention. However, vector graphics is not the leading framework for creating and manipulating 2D imagery. The reason for this reluctance of employing vector graphical frameworks is that it is difficult to handle complex behaviour of colour across the 2D domain. ...

  16. Perspectives for spintronics in 2D materials

    Han, Wei

    2016-03-01

    The past decade has been especially creative for spintronics since the (re)discovery of various two dimensional (2D) materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  17. Perspectives for spintronics in 2D materials

    Wei Han

    2016-03-01

    Full Text Available The past decade has been especially creative for spintronics since the (rediscovery of various two dimensional (2D materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  18. The MRI diagnosis of triangular fibrocartilage complex injures in the wrist%腕三角纤维软骨复合体损伤的MRI诊断

    万梦楠; 周胜法; 林锋; 陈久尊; 何家维; 郑显秋

    2016-01-01

    目的:探讨3.0T MRI在腕关节三角纤维软骨复合体(TFCC)损伤中的价值。方法回顾性分析26例TFCC损伤的MRI及X线平片、CT表现。结果26例X线检查13例阴性,5例茎突骨折,2例桡骨远端骨折,2例月骨坏死,6例尺骨径突阳性征。5例多层螺旋CT扫描,发现骨折或/和骨坏死2例。26例MRI检查中,21例诊断TFCC损伤,其中包括TFCC撕裂或穿孔8例,主要表现为在MRI脂肪抑制序列( STIR)、2D MERGE及T2 WI上点状、条片状高信号,在T1 WI序列上呈等信号;9例腕部骨折(包括尺骨茎突5例,桡骨2例,腕骨2例);3例三角骨或月骨坏死;8例尺桡骨或腕骨挫伤;10例腕关节腔积液。结论 TFCC形态细小而不规则,损伤时X线平片和CT检查价值有限,MRI多序列多方位薄层图像对显示其损伤及邻近骨质病变有重要价值。%Objective To investigate the value of 3.0 T MRI in triangular fibrocartilage complex (TFCC) injures in the wrist. Methods The MRI, X-ray and CT characteristics of 26 cases of TFCC injuries were analyzed retrospectively .Results Of the 26 cases with X-ray examination , 13 were negative cases , 5 ulnar styloid fracture , 2 distal radial fracture , 2 lunate necrosis and 6 positive ulnar styloid.5 cases underwent multi-slice CT scan, of which 2 cases had fracture or/and necrosis, others hadn’t ab-normal sign.Of the 26 patients underwent MRI examination , 21 cases were diagnosed as TFCC injuries including 8 cases with TF-CC tear or perforation which were mainly spotty and stripped hyperintense on MRI short time inverse recovery ( STIR ) , 2DMERGE and T2 WI and isointense on T 1 WI;9 were wrist fracture (5 ulnar styloid, 2 radius and 2 wrists);3 were triangular bone or lunate necrosis;8 were radius and ulna or wrist contusion and 10 wrist joints effusion.Bone contusion was long T 1 and long T2 , including bone fracture with bone trabecular or bone cortex breaking .Conclusion The

  19. 2D Barcode for DNA Encoding

    Elena Purcaru

    2011-09-01

    Full Text Available The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution – DNA2DBC – DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features of 2D barcode implementation for DNA.

  20. 2D Barcode for DNA Encoding

    Purcaru, Elena

    2012-01-01

    The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution - DNA2DBC - DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features of 2D barcode implementation for DNA.

  1. Bedform characterization through 2D spectral analysis

    Lefebvre, Alice; Ernstsen, Verner Brandbyge; Winter, Christian

    energetic peak of the 2D spectrum was found and its energy, frequency and direction were calculated. A power-law was fitted to the average of slices taken through the 2D spectrum; its slope and y-intercept were calculated. Using these results the test area was morphologically classified into 4 distinct...... characteristics using twodimensional (2D) spectral analysis is presented and tested on seabed elevation data from the Knudedyb tidal inlet in the Danish Wadden Sea, where large compound bedforms are found. The bathymetric data were divided into 20x20 m areas on which a 2D spectral analysis was applied. The most...

  2. UNITS IN $F_2D_{2p}$

    Kaur, Kuldeep; Khan, Manju

    2012-01-01

    Let $p$ be an odd prime, $D_{2p}$ be the dihedral group of order 2p, and $F_{2}$ be the finite field with two elements. If * denotes the canonical involution of the group algebra $F_2D_{2p}$, then bicyclic units are unitary units. In this note, we investigate the structure of the group $\\mathcal{B}(F_2D_{2p})$, generated by the bicyclic units of the group algebra $F_2D_{2p}$. Further, we obtain the structure of the unit group $\\mathcal{U}(F_2D_{2p})$ and the unitary subgroup $\\mathcal{U}_*(F_...

  3. Simultaneous EEG–fMRI: evaluating the effect of the cabling configuration on the gradient artefact

    EEG recordings made in combined EEG–fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artefacts are also produced in the cables used to connect the EEG cap to the amplifier. The aim of this study is to measure the effects of the connecting cable configuration on the characteristics of the GA. We measured the GA produced on two different cable configurations (a ribbon cable and a cable consisting of wires that are twisted together to form a cylindrical bundle) by gradient pulses applied on three orthogonal axes and also characterized the effect of each cable configuration on the GA generated by a multi-slice echo planar imaging sequence, as employed in typical EEG–fMRI studies. The results demonstrate that the cabling that connects the EEG cap to the amplifier can make a significant contribution to the GA recorded during EEG–fMRI studies. In particular, we demonstrate that the GA generated by a ribbon cable is larger than that produced using a twisted cable arrangement and that changes in the GA resulting from variation in the cable position are also greater for the ribbon cable. (note)

  4. Simultaneous EEG-fMRI: evaluating the effect of the cabling configuration on the gradient artefact

    Chowdhury, M. E. H.; Mullinger, Karen J.; Bowtell, Richard

    2015-06-01

    EEG recordings made in combined EEG-fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artefacts are also produced in the cables used to connect the EEG cap to the amplifier. The aim of this study is to measure the effects of the connecting cable configuration on the characteristics of the GA. We measured the GA produced on two different cable configurations (a ribbon cable and a cable consisting of wires that are twisted together to form a cylindrical bundle) by gradient pulses applied on three orthogonal axes and also characterized the effect of each cable configuration on the GA generated by a multi-slice echo planar imaging sequence, as employed in typical EEG-fMRI studies. The results demonstrate that the cabling that connects the EEG cap to the amplifier can make a significant contribution to the GA recorded during EEG-fMRI studies. In particular, we demonstrate that the GA generated by a ribbon cable is larger than that produced using a twisted cable arrangement and that changes in the GA resulting from variation in the cable position are also greater for the ribbon cable.

  5. Annotated Bibliography of EDGE2D Use

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables

  6. 2D NMR studies of biomolecules

    The work described in this thesis comprises two related subjects. The first part describes methods to derive high-resolution structures of proteins in solution using two-dimensional (2-D) NMR. The second part describes 2-D NMR studies on the interaction between proteins and DNA. (author). 261 refs.; 52 figs.; 23 tabs

  7. Applications of 2D helical vortex dynamics

    Okulov, Valery; Sørensen, Jens Nørkær

    In the paper, we show how the assumption of helical symmetry in the context of 2D helical vortices can be exploited to analyse and to model various cases of rotating flows. From theory, examples of three basic applications of 2D dynamics of helical vortices embedded in flows with helical symmetry...

  8. Annotated Bibliography of EDGE2D Use

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  9. Selection and application of multi-slice CT 3D reconstruction techniques in assisting mini-implant ahchorage implant surgery%多层螺旋CT三维重建技术在辅助微螺钉种植支抗植入中的选择应用

    陈京奕; 吴晓伟; 张洪刚; 焦建军; 张学强; 姚传臣

    2011-01-01

    背景:提高正畸支抗系统微螺钉种植体稳定性的关键在于种植前对局部骨质、骨量进行精确评估,但常规二维影像学检查,如根尖片、曲面断层摄影片、侧位头影测量片等均存在不同程度的局限性.目的:分析总结多层螺旋CT多种图像重建技术在辅助微螺钉种植支抗植入中的不同特点及优势,以便精确指导微螺钉的种植,提高其稳定性.方法:种植前以多层螺旋CT对猪颅骨进行定位扫描及多种图像重建,通过多种图像联合应用初步观测种植区骨质骨量及解剖情况,然后利用计算机在影像上精确设计三维种植角度,根据影像信息制作隧道式手术模板指导种植32枚微螺钉支抗,种植后多层螺旋CT再次扫描重建,将种植前后多层螺旋CT设计及测量角度与术后解剖组织块实物测量角度作对比分析.结果与结论:32枚微螺钉种植情况满意,无伤及邻近牙根及周围重要组织结构的情况.种植前设计与种植后多层螺旋CT测量角度比较,以及种植后多层螺旋CT测量与实物测量角度比较,在轴位面及侧断面上其差异均无显著性意义(P > 0.05),且一致性极好.说明多层螺旋CT能够提供精确而丰富的影像信息,恰当选择合理应用能充分实现微螺钉种植影像学检查目的,从而为提高种植的成功率提供可靠保障.%BACKGROUND: The key method to improve the stability of miniscrew orthodontic anchorage system is accurate preoperative bone mass evaluation in the implant region. Routine 2D image examinations such as periapical radiography and panoramic tomography and lateral cephalometric radiography have limitations.OBJECTIVE: To analyze the traits and advantages of various multi-slice CT (MSCT) reconstruction images in assisting miniscrew anchorage surgery to improve the stability of miniscrew.METHODS: Preplant MSCT scanning and various images reconstruction were made and helped to exam the peri-implant bone

  10. Inertial solvation in femtosecond 2D spectra

    Hybl, John; Albrecht Ferro, Allison; Farrow, Darcie; Jonas, David

    2001-03-01

    We have used 2D Fourier transform spectroscopy to investigate polar solvation. 2D spectroscopy can reveal molecular lineshapes beneath ensemble averaged spectra and freeze molecular motions to give an undistorted picture of the microscopic dynamics of polar solvation. The transition from "inhomogeneous" to "homogeneous" 2D spectra is governed by both vibrational relaxation and solvent motion. Therefore, the time dependence of the 2D spectrum directly reflects the total response of the solvent-solute system. IR144, a cyanine dye with a dipole moment change upon electronic excitation, was used to probe inertial solvation in methanol and propylene carbonate. Since the static Stokes' shift of IR144 in each of these solvents is similar, differences in the 2D spectra result from solvation dynamics. Initial results indicate that the larger propylene carbonate responds more slowly than methanol, but appear to be inconsistent with rotational estimates of the inertial response. To disentangle intra-molecular vibrations from solvent motion, the 2D spectra of IR144 will be compared to the time-dependent 2D spectra of the structurally related nonpolar cyanine dye HDITCP.

  11. Internal Photoemission Spectroscopy of 2-D Materials

    Nguyen, Nhan; Li, Mingda; Vishwanath, Suresh; Yan, Rusen; Xiao, Shudong; Xing, Huili; Cheng, Guangjun; Hight Walker, Angela; Zhang, Qin

    Recent research has shown the great benefits of using 2-D materials in the tunnel field-effect transistor (TFET), which is considered a promising candidate for the beyond-CMOS technology. The on-state current of TFET can be enhanced by engineering the band alignment of different 2D-2D or 2D-3D heterostructures. Here we present the internal photoemission spectroscopy (IPE) approach to determine the band alignments of various 2-D materials, in particular SnSe2 and WSe2, which have been proposed for new TFET designs. The metal-oxide-2-D semiconductor test structures are fabricated and characterized by IPE, where the band offsets from the 2-D semiconductor to the oxide conduction band minimum are determined by the threshold of the cube root of IPE yields as a function of photon energy. In particular, we find that SnSe2 has a larger electron affinity than most semiconductors and can be combined with other semiconductors to form near broken-gap heterojunctions with low barrier heights which can produce a higher on-state current. The details of data analysis of IPE and the results from Raman spectroscopy and spectroscopic ellipsometry measurements will also be presented and discussed.

  12. 2D supergravity in p+1 dimensions

    Gustafsson, H.; Lindstrom, U.

    1998-01-01

    We describe new $N$-extended 2D supergravities on a $(p+1)$-dimensional (bosonic) space. The fundamental objects are moving frame densities that equip each $(p+1)$-dimensional point with a 2D ``tangent space''. The theory is presented in a $[p+1, 2]$ superspace. For the special case of $p=1$ we recover the 2D supergravities in an unusual form. The formalism has been developed with applications to the string-parton picture of $D$-branes at strong coupling in mind.

  13. 2D Barcode for DNA Encoding

    Elena Purcaru; Cristian Toma

    2012-01-01

    The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution – DNA2DBC – DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features ...

  14. Matrix models of 2d gravity

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date

  15. 2D Saturable Absorbers for Fibre Lasers

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  16. Beltrami States in 2D Electron Magnetohydrodynamics

    Shivamoggi, B. K.

    2015-01-01

    In this paper, the Hamiltonian formulations along with the Poisson brackets for two-dimensional (2D) electron magnetohydrodynamics (EMHD) flows are developed. These formulations are used to deduce the Beltrami states for 2D EMHD flows. In the massless electron limit, the EMHD Beltrami states reduce to the force-free states, though there is no force-free Beltrami state in the general EMHD case.

  17. Matrix models and 2-D gravity

    In these lectures, I shall focus on the matrix formulation of 2-d gravity. In the first one, I shall discuss the main results of the continuum formulation of 2-d gravity, starting from the first renormalization group calculations which led to the concept of the conformal anomaly, going through the Polyakov bosonic string and the Liouville action, up to the recent results on the scaling properties of conformal field theories coupled to 2-d gravity. In the second lecture, I shall discuss the discrete formulation of 2-d gravity in term of random lattices, and the mapping onto random matrix models. The occurrence of critical points in the planar limit and the scaling limit at those critical points will be described, as well as the identification of these scaling limits with continuum 2-d gravity coupled to some matter field theory. In the third lecture, the double scaling limit in the one matrix model, and its connection with continuum non perturbative 2-d gravity, will be presented. The connection with the KdV hierarchy and the general form of the string equation will be discuted. In the fourth lecture, I shall discuss the non-perturbative effects present in the non perturbative solutions, in the case of pure gravity. The Schwinger-Dyson equations for pure gravity in the double scaling limit are described and their compatibility with the solutions of the string equation for pure gravity is shown to be somewhat problematic

  18. 2d index and surface operators

    In this paper we compute the superconformal index of 2d (2,2) supersymmetric gauge theories. The 2d superconformal index, a.k.a. flavored elliptic genus, is computed by a unitary matrix integral much like the matrix integral that computes the 4d superconformal index. We compute the 2d index explicitly for a number of examples. In the case of abelian gauge theories we see that the index is invariant under flop transition and under CY-LG correspondence. The index also provides a powerful check of the Seiberg-type duality for non-abelian gauge theories discovered by Hori and Tong. In the later half of the paper, we study half-BPS surface operators in N=2 superconformal gauge theories. They are engineered by coupling the 2d (2,2) supersymmetric gauge theory living on the support of the surface operator to the 4d N=2 theory, so that different realizations of the same surface operator with a given Levi type are related by a 2d analogue of the Seiberg duality. The index of this coupled system is computed by using the tools developed in the first half of the paper. The superconformal index in the presence of surface defect is expected to be invariant under generalized S-duality. We demonstrate that it is indeed the case. In doing so the Seiberg-type duality of the 2d theory plays an important role

  19. 2-D DOA Estimation Based on 2D-MUSIC%基于2D-MUSIC算法的DOA估计

    康亚芳; 王静; 张清泉; 行小帅

    2014-01-01

    This paper discussed the performance of classical two-dimensional DOA estimation with 2D-MUSIC, based on the mathematical model of planar array and 2D-MUSIC DOA estimation, Taking uniform planar array for example, comput-er simulation experiment was carried for the effect of three kinds of different parameters on 2-D DOA estimation, and the simulation results were analyzed. And also verification test about the corresponding algorithm performance under the differ-ent parameters was discussed.%利用经典的2D-MUSIC算法对二维阵列的DOA估计进行了研究,在平面阵列数学模型以及2D-MUSIC算法的DOA估计模型基础上,以均匀平面阵列为例,对3种不同参数的DOA估计进行了计算机仿真,分析了仿真结果。得出了在不同参数变化趋势下DOA估计的相应变化情况。

  20. 下腔静脉病变的 CT 与 MRI 诊断价值%Study on the significance of CT scanning and MRI in diagnosis of lesions in inferior vena cava

    王文生; 丁长青; 孙迎迎; 罗慧; 代兰兰; 丁爱兰

    2014-01-01

    Objective To explore the significance of multi - slice spiral CT scanning and MRI in diagnosis of lesions in inferior vena cava (IVC). Methods The data of 16 - slice spiral CT scanning and 0. 35T MRI imaging of 80 patients with clinically confirmed IVC lesions were retrospectively analyzed. The CT scanning was given with multi - phase contrast - enhanced examination,MRI was mainly by plain scanning. These examinations were focused on analyzing the scope and nature of inferior vena cava. Results Among these 80 cases,9 cases were congenital malformation of IVC(5 cases were diagnosed by CT scanning,and 4 cases by MRI),formation of emboli in 36 cases(including 5 with thrombo-sis,31 with cancer embolus;32 cases were diagnosed by CT,and 4 cases by MRI ),16 cases of Budd Chiari syndrome(diagnosed by CT scan-ning in 15 cases,MRI in 1 case),stenosis caused by external pressure in 12 cases(diagnosed by CT scanning in 8 cases,and by MRI in 4 ca-ses),placement of stent in 3 cases(diagnosed by CT scanning). Conclusion Multi - slice spiral CT scanning and MRI can rapidly,accurately and non - invasively demonstrate IVC and its lesions,hence they are worthy to be applied for clinical diagnosis.%目的:探讨多层螺旋 CT 及 MRI 在下腔静脉病变中的诊断价值。方法回顾性分析临床证实的80例下腔静脉病变的16层螺旋 CT 及0.35T MRI 资料,CT 以多期增强检查为主,MRI 以平扫为主。重点分析下腔静脉病变部位、范围及性质。结果检出下腔静脉先天畸形9例(其中 CT 诊断5例,MRI 诊断4例),下腔静脉栓子形成36例(其中血栓5例,癌栓31例;CT 诊断32例,MRI 诊断4例),布加综合征16例(其中 CT 诊断15例,MRI 诊断1例),外压性狭窄12例(其中 CT 诊断8例,MRI 诊断4例),支架置入3例(均为 CT 诊断)。结论多层螺旋 CT 及 MRI 能够快速、无创较为准确显示下腔静脉及其病变,值得临床应用。

  1. Characteristics and diagnostic value of multi-slice spiral computed tomography examination of gastrointestinal lipoma%胃肠道脂肪瘤的多排螺旋CT检查特征与诊断价值

    郑汉朋; 王晓阳; 藤陈迪; 许崇永; 郑祥武; 邱乾德

    2016-01-01

    Objective To investigate the characteristics and diagnostic value of multi-slice spiral computed tomography (MSCT) examination of gastrointestinal lipoma.Methods The cross-sectional study was adopted.The clinicopathological data of 96 patients with gastrointestinal lipoma including 32 from the Second Hospital Affiliated to Wenzhou Medical University,30 from the First Hospital Affiliated to Wenzhou Medical University,17 from the Ruian People's Hospital of Zhejiang,11 from the Yueqing People's Hospital,3 from the Wenzhou Central Hospital and 3 from the Wenzhou People's Hospital from December 2006 to September 2015 were collected.All patients were fasted for 8 hours prior to the examination,and partial patients underwent enhanced scan after the conventional CT scanning with breathless scanning and no abdominal pressure.Coronal and sagittal images of gastrointestinal tract including the tumor were administrated with multiple planar reconstruction (MPR)techniques of Reformat software.Based on MPR images,the curves along the gastrointestinal tract were drawn,voxel distributed along the curve track were reconstructed,and curved planar reconstruction (CPR) images were obtained.The patients received operation or follow-up according to individual characteristics after examinations.The patients undergoing operation were followed up for detecting tumor recurrence and metastasis by CT examination and patients receiving follow-up were observed by endoscopy for detecting changes of tumor size and morphology up to June 2015.The analysis indexes included tumor location and size,performance of MSCT examination (tumor shape,density,margin,intussusceptions,enhanced MSCT examination),intraoperative findings,results of pathological examination and results of follow-up.Measurement data with normal distribution were presented as i ± s.Results All the 96 patients received MSCT plain scan and the 42 received enhanced MSCT scan.The CPR images in 30 patients were collected.(1) Tumor location

  2. Uncertainty estimations for quantitative in vivo MRI T1 mapping

    Polders, Daniel L.; Leemans, Alexander; Luijten, Peter R.; Hoogduin, Hans

    2012-11-01

    Mapping the longitudinal relaxation time (T1) of brain tissue is of great interest for both clinical research and MRI sequence development. For an unambiguous interpretation of in vivo variations in T1 images, it is important to understand the degree of variability that is associated with the quantitative T1 parameter. This paper presents a general framework for estimating the uncertainty in quantitative T1 mapping by combining a slice-shifted multi-slice inversion recovery EPI technique with the statistical wild-bootstrap approach. Both simulations and experimental analyses were performed to validate this novel approach and to evaluate the estimated T1 uncertainty in several brain regions across four healthy volunteers. By estimating the T1 uncertainty, it is shown that the variation in T1 within anatomic regions for similar tissue types is larger than the uncertainty in the measurement. This indicates that heterogeneity of the inspected tissue and/or partial volume effects can be the main determinants for the observed variability in the estimated T1 values. The proposed approach to estimate T1 and its uncertainty without the need for repeated measurements may also prove to be useful for calculating effect sizes that are deemed significant when comparing group differences.

  3. Abdominal MRI

    ... kidney and ureter Insulinoma Islet of Langerhans tumor Medullary cystic disease Multiple endocrine neoplasia (MEN) I Multiple endocrine neoplasia ( ... kidney and ureter Insulinoma Kidney stones Lymphofollicular ... kidney disease MRI Multiple endocrine neoplasia (MEN) I Multiple endocrine ...

  4. Pediatric MRI

    U.S. Department of Health & Human Services — The NIH Study of Normal Brain Development is a longitudinal study using anatomical MRI, diffusion tensor imaging (DTI), and MR spectroscopy (MRS) to map pediatric...

  5. Multi slice CT MPR technology and MR of cruciate ligament Comparison of damage diagnosis%多排CT的MPR技术与MR对交叉韧带损伤影诊断的对比

    胡瑞峰; 王琨; 王姝君

    2015-01-01

    Knee ligament damage is very common clinical, MRI is the knee ligament damage check ideal check method, but MRI equipment expensive, a lot of basic-level hospital has not been popular, and MR imaging is the signal imaging, video con-tinuity and 3 d stereoscopic feeling bad, if have metallic implants, are not for MR check, and will influence the MSCT small. At present, multidetector-row CT increasing popularity, multidetector-row CT MPR reconstruction technique in the whole body each system widely used, and the MSCT can also found joint concurrent damage inside and outside, the scanning bilateral knee, in addition, without changes to limb natural postures, reduce pain patients. Will the knee ligament damage is concerned, the do-mestic rarely reported in the literature, through the multidetector-row CT (MSCT) image reconstruction and MPR technology for knee ligament damage across the image diagnosis and an MRI results of the comparison of the science, with the diagnosis rate 97%, and multidetector-row CT of the MPR reconstruction technique for knee ligament damage the diagnostic value of more than MR examination has authenticity, scientific and practical, has the extensive use of the value and popularize value.%膝关节韧带损伤临床上很常见,MRI是目前膝关节韧带损伤检查较理想的检查方法,但MRI设备昂贵,很多基层医院尚未普及,据不完全统计本市的MRI占20%,而且MR影像是信号成像,影像连续性及三维立体感差,如有金属内置物,则不能进行MR检查,而MSCT则影响较小。目前,多排螺旋CT日益普及,多排螺旋CT的MPR重建技术在全身各个系统广泛应用,且MSCT可同时发现关节内外的并发损伤,可同时扫描双侧膝关节,另外,不需改动患肢自然体位,减少患者痛苦。就膝关节韧带损伤而言,国内文献报道很少,通过多排螺旋CT (MSCT)影像三维重建及MPR技术对膝关节交叉韧带损伤的影像诊断与MRI

  6. Optical modulators with 2D layered materials

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  7. Automatic Contour Extraction from 2D Image

    Panagiotis GIOANNIS

    2011-03-01

    Full Text Available Aim: To develop a method for automatic contour extraction from a 2D image. Material and Method: The method is divided in two basic parts where the user initially chooses the starting point and the threshold. Finally the method is applied to computed tomography of bone images. Results: An interesting method is developed which can lead to a successful boundary extraction of 2D images. Specifically data extracted from a computed tomography images can be used for 2D bone reconstruction. Conclusions: We believe that such an algorithm or part of it can be applied on several other applications for shape feature extraction in medical image analysis and generally at computer graphics.

  8. 2D microwave imaging reflectometer electronics.

    Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

    2014-11-01

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program. PMID:25430247

  9. 2D microwave imaging reflectometer electronics

    Spear, A. G.; Domier, C. W., E-mail: cwdomier@ucdavis.edu; Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C. [Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  10. 多层螺旋CT平扫联合尿路重建在急性肾绞痛诊断中的临床应用%Clinical application of multi-slice helical CT plain scan combined with urinary reconstruction in diagnosis of acute renal colic

    陈刚; 吴小候; 尹志康; 何云锋

    2011-01-01

    目的 探讨多层螺旋CT平扫联合尿路重建在急性肾绞痛诊断中的的临床应用价值.方法 将126例急诊肾绞痛患者随机分两组:CT组(67例)和静脉尿路造影(IVU)组(59例),CT组行多层(16层或64层)螺旋CT平扫联合尿路重建,IVU组行相关准备后行腹部X线平片(KUB)联合IVU检查.在明确诊断为输尿管梗阻或输尿管结石后,急诊行输尿管镜碎石术或置管治疗,比较两组患者的术前结石确诊率、肾绞痛缓解时间、住院时间及住院总费用等.结果 所有患者术后肾绞痛均缓解,CT组术前结石确诊率明显高于IVU组(P<0.05),CT组肾绞痛缓解时间和住院时间短于IVU组(P<0.05),CT组住院总费与IVU组比较差异无统计学意义(P>0.05).结论 多层螺旋CT平扫联合尿路重建对于急诊肾绞痛患者的诊治是高效和相对经济的.%Objective To investigate clinical application of multi-slice helical CT plain scan combined with urinary reconstruction in diagnosis of acute renal colic. Methods 126 patients with acute renal colic were randomized divided into two groups. 67 cases were diagnosed by multi-slice helical CT combined with urinary reconstruction and 59 cases were diagnosed by abdominal plain film radiography combined with IVU. All patients were treated by ureteroscope lithotripsy. The stone diagnosis rate was compared as well as the renal colic time , the hospitalization time and the hospitalization cost. Results The stone diagnosis rate in CT group was more than that in IVU group(P<0. 05). However,the renal colic time hospitalization time in CT group was less than that in IVU group as well as hospitalization time(P<0. 05). There was no significantly difference on the hospitalization cost between two groups(P>0. 05). Conclusion Multi-slice helical CT plain scan combined with urinary reconstruction is efficient and economic in diagnosis of acute renal colic.

  11. Multidetector CT and MRI in pancreatic diseases

    Multidetector CT and MRI are the most efficient non invasive techniques in the assessment of pancreatic diseases. As with MRI, multidetector CT has now become an all in one examination using 2 D and 3 D multiplanar reformations with the ability to perform with high accuracy: a) vascular assessment using MIP reconstruction and b) biliary and pancreatic ducts assessment using minIP reconstruction. This review compares and illustrates the respective advantages of MRI and multidetector CT in the assessment of pancreatic diseases. (authors)

  12. Path integral quantization of 2 D- gravity

    2 D- gravity is investigated using the Hamilton-Jacobi formalism. The equations of motion and the action integral are obtained as total differential equations in many variables. The integrability conditions, lead us to obtain the path integral quantization without any need to introduce any extra un-physical variables. (author)

  13. Port Adriano, 2D-Model tests

    Burcharth, Hans F.; Meinert, Palle; Andersen, Thomas Lykke

    This report present the results of 2D physical model tests (length scale 1:50) carried out in a waveflume at Dept. of Civil Engineering, Aalborg University (AAU). The objective of the tests was: To identify cross section design which restrict the overtopping to acceptable levels and to record the...

  14. Baby universes in 2d quantum gravity

    Ambjorn, J.; S. Jain; G. Thorleifsson

    1993-01-01

    We investigate the fractal structure of $2d$ quantum gravity, both for pure gravity and for gravity coupled to multiple gaussian fields and for gravity coupled to Ising spins. The roughness of the surfaces is described in terms of baby universes and using numerical simulations we measure their distribution which is related to the string susceptibility exponent $\\g_{string}$.

  15. Horns Rev II, 2-D Model Tests

    Andersen, Thomas Lykke; Frigaard, Peter

    This report present the results of 2D physical model tests carried out in the shallow wave flume at Dept. of Civil Engineering, Aalborg University (AAU), on behalf of Energy E2 A/S part of DONG Energy A/S, Denmark. The objective of the tests was: to investigate the combined influence of the pile...

  16. Magnetic Resonance Imaging (MRI)

    ... Resonance Imaging (MRI) What is an MRI? MRI stands for Magnetic Resonance Imaging. It is an important ... MRI is often used for diagnosis or for monitoring disease. For example, if someone is having severe ...

  17. MRI Safety during Pregnancy

    ... News Physician Resources Professions Site Index A-Z MRI Safety During Pregnancy Magnetic resonance imaging (MRI) Illness ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor ...

  18. Portable MRI

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  19. Portable MRI

    Espy, Michelle A. [Los Alamos National Laboratory

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  20. ORION, Post-processor for Finite Elements Program NIKE2D and DYNA2D

    Description of program or function: ORION is an interactive post- processor for the analysis programs NIKE2D (NESC 9923), DYNA2D (NESC 9910), TOPAZ, TOPAZ2D (NESC9801), GEM2D (NESC9679), and TACO2D. ORION reads the binary plot data files generated by the two- dimensional finite element programs used at LLNL. Contours and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has the capability to plot color fringes, contour lines, vector plots, principal stress lines, deformed meshes and material outlines, time histories, reaction forces along constraint boundaries, interface pressures along slide lines, and user-supplied labels

  1. Fetal MRI

    New, ultrafast sequences have made it possible to obtain MR images of the fetus without maternal sedation or immobilization of the fetus itself. While fetal MRI began as an adjunct to ultrasound, it has now been shown that MRI can provide additional information that may change prognosis, the management of pregnancy, or the treatment of the newborn child. It is of particular value in the assessment of malformations of the central nervous system. The steady development and adaptation of MR-sequences to the needs of fetal imaging has led to new indications that can support prognostic and therapeutic decisions. (orig.)

  2. Fetal MRI

    Prayer, D.; Brugger, P.C. [University Hospital of Vienna (Austria). Division of Neuroradiology

    2004-07-01

    New, ultrafast sequences have made it possible to obtain MR images of the fetus without maternal sedation or immobilization of the fetus itself. While fetal MRI began as an adjunct to ultrasound, it has now been shown that MRI can provide additional information that may change prognosis, the management of pregnancy, or the treatment of the newborn child. It is of particular value in the assessment of malformations of the central nervous system. The steady development and adaptation of MR-sequences to the needs of fetal imaging has led to new indications that can support prognostic and therapeutic decisions. (orig.)

  3. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  4. The development of the RF-pulse for the low level SAR used by the MRI

    The Magnetic Resonance Imaging (MRI) is important diagnostic image equipment as a medical instrument which does not use the radiation. The signal acquisition of the MRI irradiates human body with electromagnetic wave ( radio frequency : RF-pulse), and it collects MR signal of the human body. The safety of RF-pulse used by MRI has been defined at specific absorption ratio (SAR) [Watt/Kg]. Recently, there was a case in which the SAR became high-level by a diversity of the imaging sequence for the MRI in the selection of the imaging procedure. The effect of the electromagnetic wave on human body had to be considered, when the SAR became high-level, and there was the necessity of the development of the RF-pulse for the low level SAR. We produced the RF-pulse of the SAR for the low level experimentally. The trial manufacture RF-pulse carried out the imaging test by MRI equipment used by the clinic actually. The radiofrequency pulse used in SAR type sequence for low level produced original functional type radiofrequency pulse based on the Fourier cosine development experimentally. Evaluation method of original functional type radiofrequency pulse were frequency characteristics and slice profile characteristics required by the numerical simulation analysis using Bloch equation. In the clinical equipment, the following were carried out. Slice thickness adjustment and optimization of the power condition degree of 90-180. Low SAR type pulse sequence using original functional type RF-pulse reduced RF watt [K W] to 25.6%. And, contrast lowering in the multi-slice imaging was suppressed at 12.5%. The improvement was able to realize SAR reduction and picture quality on imaging pulse sequence using the low SAR type RF-pulse. (author)

  5. 4-D flow magnetic resonance imaging: blood flow quantification compared to 2-D phase-contrast magnetic resonance imaging and Doppler echocardiography

    Doppler echocardiography (echo) is the reference standard for blood flow velocity analysis, and two-dimensional (2-D) phase-contrast magnetic resonance imaging (MRI) is considered the reference standard for quantitative blood flow assessment. However, both clinical standard-of-care techniques are limited by 2-D acquisitions and single-direction velocity encoding and may make them inadequate to assess the complex three-dimensional hemodynamics seen in congenital heart disease. Four-dimensional flow MRI (4-D flow) enables qualitative and quantitative analysis of complex blood flow in the heart and great arteries. The objectives of this study are to compare 4-D flow with 2-D phase-contrast MRI for quantification of aortic and pulmonary flow and to evaluate the advantage of 4-D flow-based volumetric flow analysis compared to 2-D phase-contrast MRI and echo for peak velocity assessment in children and young adults. Two-dimensional phase-contrast MRI of the aortic root, main pulmonary artery (MPA), and right and left pulmonary arteries (RPA, LPA) and 4-D flow with volumetric coverage of the aorta and pulmonary arteries were performed in 50 patients (mean age: 13.1 ± 6.4 years). Four-dimensional flow analyses included calculation of net flow and regurgitant fraction with 4-D flow analysis planes similarly positioned to 2-D planes. In addition, 4-D flow volumetric assessment of aortic root/ascending aorta and MPA peak velocities was performed and compared to 2-D phase-contrast MRI and echo. Excellent correlation and agreement were found between 2-D phase-contrast MRI and 4-D flow for net flow (r = 0.97, P < 0.001) and excellent correlation with good agreement was found for regurgitant fraction (r = 0.88, P < 0.001) in all vessels. Two-dimensional phase-contrast MRI significantly underestimated aortic (P = 0.032) and MPA (P < 0.001) peak velocities compared to echo, while volumetric 4-D flow analysis resulted in higher (aortic: P = 0.001) or similar (MPA: P = 0.98) peak

  6. 4-D flow magnetic resonance imaging: blood flow quantification compared to 2-D phase-contrast magnetic resonance imaging and Doppler echocardiography

    Gabbour, Maya [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging 9, Chicago, IL (United States); Schnell, Susanne [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Jarvis, Kelly [Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Evanston, IL (United States); Robinson, Joshua D. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Pediatrics, Division of Pediatric Cardiology, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Pediatrics, Chicago, IL (United States); Markl, Michael [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Evanston, IL (United States); Rigsby, Cynthia K. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging 9, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States)

    2015-06-15

    Doppler echocardiography (echo) is the reference standard for blood flow velocity analysis, and two-dimensional (2-D) phase-contrast magnetic resonance imaging (MRI) is considered the reference standard for quantitative blood flow assessment. However, both clinical standard-of-care techniques are limited by 2-D acquisitions and single-direction velocity encoding and may make them inadequate to assess the complex three-dimensional hemodynamics seen in congenital heart disease. Four-dimensional flow MRI (4-D flow) enables qualitative and quantitative analysis of complex blood flow in the heart and great arteries. The objectives of this study are to compare 4-D flow with 2-D phase-contrast MRI for quantification of aortic and pulmonary flow and to evaluate the advantage of 4-D flow-based volumetric flow analysis compared to 2-D phase-contrast MRI and echo for peak velocity assessment in children and young adults. Two-dimensional phase-contrast MRI of the aortic root, main pulmonary artery (MPA), and right and left pulmonary arteries (RPA, LPA) and 4-D flow with volumetric coverage of the aorta and pulmonary arteries were performed in 50 patients (mean age: 13.1 ± 6.4 years). Four-dimensional flow analyses included calculation of net flow and regurgitant fraction with 4-D flow analysis planes similarly positioned to 2-D planes. In addition, 4-D flow volumetric assessment of aortic root/ascending aorta and MPA peak velocities was performed and compared to 2-D phase-contrast MRI and echo. Excellent correlation and agreement were found between 2-D phase-contrast MRI and 4-D flow for net flow (r = 0.97, P < 0.001) and excellent correlation with good agreement was found for regurgitant fraction (r = 0.88, P < 0.001) in all vessels. Two-dimensional phase-contrast MRI significantly underestimated aortic (P = 0.032) and MPA (P < 0.001) peak velocities compared to echo, while volumetric 4-D flow analysis resulted in higher (aortic: P = 0.001) or similar (MPA: P = 0.98) peak

  7. Branes in the 2D black hole

    Ribault, Sylvain E-mail: ribault@mth.kcl.ac.uk; Schomerus, Volker

    2004-02-01

    We present a comprehensive analysis of branes in the Euclidean 2D black hole (cigar). In particular, exact boundary states and annulus amplitudes are provided for D0-branes which are localized at the tip of the cigar as well as for two families of extended D1 and D2-branes. Our results are based on closely related studies for the Euclidean AdS3 model and, as predicted by the conjectured duality between the 2D black hole and the sine-Liouville model, they share many features with branes in Liouville theory. New features arise here due to the presence of closed string modes which are localized near the tip of the cigar. The paper concludes with some remarks on possible applications to exact tachyon condensation and matrix models. (author)

  8. Branes in the 2D black hole

    Ribault, S; Ribault, Sylvain; Schomerus, Volker

    2004-01-01

    We present a comprehensive analysis of branes in the Euclidean 2D black hole (cigar). In particular, exact boundary states and annulus amplitudes are provided for D0-branes which are localized at the tip of the cigar as well as for two families of extended D1 and D2-branes. Our results are based on closely related studies for the Euclidean AdS3 model and, as predicted by the conjectured duality between the 2D black hole and the sine-Liouville model, they share many features with branes in Liouville theory. New features arise here due to the presence of closed string modes which are localized near the tip of the cigar. The paper concludes with some remarks on possible applications to exact tachyon condensation and matrix models.

  9. Branes in the 2D black hole

    We present a comprehensive analysis of branes in the Euclidean 2D black hole (cigar). In particular, exact boundary states and annulus amplitudes are provided for D0-branes which are localized at the tip of the cigar as well as for two families of extended D1 and D2-branes. Our results are based on closely related studies for the Euclidean AdS3 model and, as predicted by the conjectured duality between the 2D black hole and the sine-Liouville model, they share many features with branes in Liouville theory. New features arise here due to the presence of closed string modes which are localized near the tip of the cigar. The paper concludes with some remarks on possible applications to exact tachyon condensation and matrix models. (author)

  10. 2-D geometrical analysis of deformation

    Engineering structures such as dams, bridges, high rise buildings, etc. are subject to deformation. Deformation survey is therefore necessary to determine the magnitude and direction of such movements for the purpose of safety assessment. In this study, a strategy for two-step analyses for deformation survey rising the two dimensional (2-D) geodetic method has been developed, consisting of independent least squares estimation (LSE) of each epoch followed by deformation detection. Important aspects on LSE include global and local testing. In deformation detection, the following aspects were implemented; datum definition by the user. determination of stable datum points, geometrical analysis of deformation and graphic presentation. The developed strategy has been implemented in three computer programs, COMPUT, DEFORM and STRANS. Tests carried out with simulated and known data show that the developed strategy and programs are applicable for 2-D geometrical detection of deformation. (Author)

  11. MRI zoo

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard proced...

  12. Fetal MRI

    Ultrasonography is the method of choice for prenatal malformation screening, but it does not always provide sufficient information for correct diagnosis or adequate abnormality evaluation. Fetal MRI is increasingly being used to complete sonographic findings. It was initially used for evaluation of cerebral abnormalities but is increasingly being applied to other fetal areas. In vivo investigation of fetal brain maturation has been enhanced by MRI. An adequate analysis of fetal chest and abdomen can be achieved with fast T2-, T1-weighted and diffusion-weighted imaging (DWI). The advantages include the great field of view and the excellent soft tissue contrast. This allows correct diagnosis of congenital diaphragmatic hernia and evaluation of the consequences on pulmonary growth. Other pulmonary malformations, such as cystic adenomatoid malformation, sequestration and brochogenic cysts, can also be easily identified. Renal position can be quickly determined using DWI sequences and renal agenesia can be easily diagnosed with only one sequence. Prenatal MRI is virtually as effective as postnatal examination, dispenses with transport of a potentially very ill newborn, and provides logistic advantages. Therefore, prenatal MRI is useful for adequate postnatal treatment of newborns with malformations. (orig.)

  13. Realistic and efficient 2D crack simulation

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  14. 2D materials: Graphene and others

    Bansal, Suneev Anil; Singh, Amrinder Pal; Kumar, Suresh

    2016-05-01

    Present report reviews the recent advancements in new atomically thick 2D materials. Materials covered in this review are Graphene, Silicene, Germanene, Boron Nitride (BN) and Transition metal chalcogenides (TMC). These materials show extraordinary mechanical, electronic and optical properties which make them suitable candidates for future applications. Apart from unique properties, tune-ability of highly desirable properties of these materials is also an important area to be emphasized on.

  15. 2D-Tasks for Cognitive Rehabilitation

    Caballero Hernandez, Ruth; Martinez Moreno, Jose Maria; García Molina, A.; Ferrer Celma, S.; Solana Sánchez, Javier; Sanchez Carrion, R.; Fernandez Casado, E.; Pérez Rodríguez, Rodrigo; Gomez Pulido, A.; Anglès Tafalla, C.; Cáceres Taladriz, César; Ferre Vergada, M.; Roig Rovira, Teresa; Garcia Lopez, P.; Tormos Muñoz, Josep M.

    2011-01-01

    Neuropsychological Rehabilitation is a complex clinic process which tries to restore or compensate cognitive and behavioral disorders in people suffering from a central nervous system injury. Information and Communication Technologies (ICTs) in Biomedical Engineering play an essential role in this field, allowing improvement and expansion of present rehabilitation programs. This paper presents a set of cognitive rehabilitation 2D-Tasks for patients with Acquired Brain Injury (ABI). These t...

  16. Engineering light outcoupling in 2D materials

    Lien, Derhsien

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  17. Advanced flow MRI: emerging techniques and applications.

    Markl, M; Schnell, S; Wu, C; Bollache, E; Jarvis, K; Barker, A J; Robinson, J D; Rigsby, C K

    2016-08-01

    Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented. PMID:26944696

  18. Interparticle attraction in 2D complex plasmas

    Kompaneets, Roman; Ivlev, Alexei V

    2015-01-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecular-like. In this Letter, we propose how to achieve a molecular-like interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  19. 2D vector-cyclic deformable templates

    Schultz, Nette; Conradsen, Knut

    1998-01-01

    In this paper the theory of deformable templates is a vector cycle in 2D is described. The deformable template model originated in (Grenander, 1983) and was further investigated in (Grenander et al., 1991). A template vector distribution is induced by parameter distribution from transformation...... matrices applied to the vector cycle. An approximation in the parameter distribution is introduced. The main advantage by using the deformable template model is the ability to simulate a wide range of objects trained by e.g. their biological variations, and thereby improve restoration, segmentation and...

  20. Limit theorems for 2D invasion percolation

    Damron, Michael

    2010-01-01

    We prove limit theorems and variance estimates for quantities related to ponds and outlets for 2D invasion percolation. We first exhibit several properties of a sequence (O(n)) of outlet variables, the n-th of which gives the number of outlets in the box centered at the origin of side length 2^n. The most important of these properties describe the sequence's renewal structure and exponentially fast mixing behavior. We use these to prove a central limit theorem and strong law of large numbers for (O(n)). We then show consequences of these limit theorems for the pond radii and outlet weights.

  1. Instant HTMl5 2D platformer

    Temple, Aidan

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. The step-by-step approach taken by this book will show you how to develop a 2D HTML5 platformer-based game that you will be able to publish to multiple devices.This book is great for anyone who has an interest in HTML5 games development, and who already has a basic to intermediate grasp on both the HTML markup and JavaScript programming languages. Therefore, due to this requirement, the book will not discuss the inner workings of either of these languages but will instead attempt to

  2. Interparticle Attraction in 2D Complex Plasmas

    Kompaneets, Roman; Morfill, Gregor E.; Ivlev, Alexei V.

    2016-03-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecularlike. In this Letter, we propose how to achieve a molecularlike interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  3. Periodically sheared 2D Yukawa systems

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates

  4. Phase Engineering of 2D Tin Sulfides.

    Mutlu, Z; Wu, RJ; Wickramaratne, D.; Shahrezaei, S; Liu, C; Temiz, S; Patalano, A; M Ozkan; Lake, RK; Mkhoyan, KA; Ozkan, CS

    2016-01-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2...

  5. Battlefield MRI

    Espy, Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-01

    Magnetic Resonance Imaging is the best method for non-invasive imaging of soft tissue anatomy, saving countless lives each year. It is regarded as the gold standard for diagnosis of mild to moderate traumatic brain injuries. Furthermore, conventional MRI relies on very high, fixed strength magnetic fields (> 1.5 T) with parts-per-million homogeneity, which requires very large and expensive magnets.

  6. Photocurrent spectroscopy of 2D materials

    Cobden, David

    Confocal photocurrent measurements provide a powerful means of studying many aspects of the optoelectronic and electrical properties of a 2D device or material. At a diffraction-limited point they can provide a detailed absorption spectrum, and they can probe local symmetry, ultrafast relaxation rates and processes, electron-electron interaction strengths, and transport coefficients. We illustrate this with several examples, once being the photo-Nernst effect. In gapless 2D materials, such as graphene, in a perpendicular magnetic field a photocurrent antisymmetric in the field is generated near to the free edges, with opposite sign at opposite edges. Its origin is the transverse thermoelectric current associated with the laser-induced electron temperature gradient. This effect provides an unambiguous demonstration of the Shockley-Ramo nature of long-range photocurrent generation in gapless materials. It also provides a means of investigating quasiparticle properties. For example, in the case of graphene on hBN, it can be used to probe the Lifshitz transition that occurs due to the minibands formed by the Moire superlattice. We also observe and discuss photocurrent generated in other semimetallic (WTe2) and semiconducting (WSe2) monolayers. Work supported by DoE BES and NSF EFRI grants.

  7. Multienzyme Inkjet Printed 2D Arrays.

    Gdor, Efrat; Shemesh, Shay; Magdassi, Shlomo; Mandler, Daniel

    2015-08-19

    The use of printing to produce 2D arrays is well established, and should be relatively facile to adapt for the purpose of printing biomaterials; however, very few studies have been published using enzyme solutions as inks. Among the printing technologies, inkjet printing is highly suitable for printing biomaterials and specifically enzymes, as it offers many advantages. Formulation of the inkjet inks is relatively simple and can be adjusted to a variety of biomaterials, while providing nonharmful environment to the enzymes. Here we demonstrate the applicability of inkjet printing for patterning multiple enzymes in a predefined array in a very straightforward, noncontact method. Specifically, various arrays of the enzymes glucose oxidase (GOx), invertase (INV) and horseradish peroxidase (HP) were printed on aminated glass surfaces, followed by immobilization using glutardialdehyde after printing. Scanning electrochemical microscopy (SECM) was used for imaging the printed patterns and to ascertain the enzyme activity. The successful formation of 2D arrays consisting of enzymes was explored as a means of developing the first surface confined enzyme based logic gates. Principally, XOR and AND gates, each consisting of two enzymes as the Boolean operators, were assembled, and their operation was studied by SECM. PMID:26214072

  8. Comments on Thermalization in 2D CFT

    de Boer, Jan

    2016-01-01

    We revisit certain aspects of thermalization in 2D CFT. In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a BTZ black hole. The extra conserved charges, while rendering $c < 1$ theories essentially integrable, therefore seem to have little effect o...

  9. 2-D or not 2-D, that is the question: A Northern California test

    Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D

    2005-06-06

    Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7{le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter that was generally 10-30% smaller. For complex regions where data are plentiful, a 2-D approach can significantly improve upon the simple 1-D assumption. In regions where only 1-D coda correction is available it is

  10. Application value of multi-slice spiral CT image post-processing technique in the diagnosis of tracheal and bronchus foreign body in children%多层螺旋CT后处理技术对小儿气管、支气管异物的诊断价值

    巫恒平; 仲建全; 郭欢

    2015-01-01

    目的:探讨多层螺旋CT图像后处理技术在小儿气管、支气管异物诊断中的应用价值。方法通过对我院25例疑似支气管异物的患儿行多层螺旋CT扫描,采用MPR、Min IP、VR及VE等后处理技术,分析并比较其在气管、支气管异物中的诊断价值。结果经临床纤维支气管镜证实为气管、支气管异物的25例患儿均获得清晰的CT图像及后处理图像,多平面重建(MPR)对异物显示较佳,显示率为100%(25/25),容积再现(VR)能明确异物的位置及与气管的关系,显示率为97%(24/25),最小密度投影(Min IP)对异物的测量较精确,显示率为97%(24/25),及仿真内窥镜(VE)能准确显示异物在气管内的位置及对气管的堵塞情况。结论 MSCT后处理技术在小儿气管、支气管异物诊断中准确率较高,可成为首选的影像学检查方法。%Objective To explore the application value of multi-slice spiral CT (MSCT) image post-process-ing technique in the diagnosis of tracheal and bronchus foreign body in children. Methods Twenty-five children sus-pected with bronchial foreign bodies in our hospital were scanned by multi-slice spiral CT. Then the imaging data were processed by techniques of multi planar reconstruction (MPR), minimum intensity projection (Min IP), volume rendering (VR) and virtual endoscopy (VE). The diagnosis value of the techniques for trachea, bronchial foreign body was analyzed and compared. Results The 25 cases all obtained clear CT images and post-processed images. MPR displayed the foreign body best, with the display rate of 100%(25/25). VR could clear display foreign body and its re-lationship with the trachea, with the display rate of 97%(24/25). Min IP was good at distinguish the accurate measure-ment of the foreign body, and the display rate was 97%(24/25). VE could show the foreign bodies in the trachea of the position and the blockage of the trachea accurately. Conclusion The MSCT image post

  11. The influence of gallbladder fossa fluid accumulation on gallbladder wall thickness in liver cirrhosis on sonographic imaging correlation with multi-slice CT scanning%利用CT三维重建分析肝硬化伴胆囊窝积液对胆囊壁超声成像的影响

    谭洁莹; 韦程纲; 谢琦

    2012-01-01

    目的:探讨肝硬化伴胆囊窝积液病者胆囊壁超声与CT三维重建在影像成像以及胆囊壁厚度测量的方面上对比差异.方法:对比39例患者于空腹状态同时行超声以及多层螺旋CT检查的影像图像,B超和CT测量胆囊厚度情况,绘制散点图,并进行Pearson相关性分析,应用配对样本t检验比较胆囊壁厚度情况.结果:①与CT三维重建图像对比,发现其中31例出现胆囊窝积液超声漏诊情况,并且发现胆囊壁厚度的超声测量值,存在高估情况的16例,低估情况2例.②B超与CT胆囊壁厚度的测量值相关系数为0.648 (P<0.000).③B超测量胆囊壁厚度((6.2±2.6)mm)较CT测量胆囊壁厚度((4.5±2.0)mm)平均值更大,测量差异具有统计学意义(t=4.465,P<0.000),变异系数分别为0.42、0.44.结论:局限性胆囊窝积液在CT检查中检出率较超声高,对肝硬化患者胆囊壁增厚与局限性胆囊窝积液能够更准确地进行鉴别诊断.%Objective: To discuss the difference of gallbladder wall thickness in liver cirrhosis with gallbladder fossa fluid accumulation on ultrasound scanning and CT multi-plane reconstruction images. Materials and Methods: Ultrasound scanning and multi-slice CT were performed in 39 patients who had gallbladder fossa fluid accumulation with liver cirrhosis, all cases were under fasting condition. Gallbladder wall thickness was measured both on ultrasonographic and multi —slice CT 3D reconstruction images. The scatter diagram was drawn and Pearson correlation analysis and paired sample t test comparison of gallbladder wall thickness were also carried out. Result: Compared with multi-plane CT reconstruction, (1) Ultrasound missed the diagnosis of gallbladder fossa fluid accumulation in 31 cases, over estimation of gallbladder wall thickness in 16 cases, and under estimation of the thickness in 2 cases. (2)The correlation coefficient of ultrasound detection of gallbladder wall thickness with CT detection was

  12. 多层螺旋CT泌尿系造影诊断上尿路梗阻性疾病20例分析%Application of multi-slice spiral CT urography for diagnosis of upper urinary tract obstructive disorder in 20 cases

    管军; 金洁; 朱文海; 陆进; 诸伟; 吴少峰

    2013-01-01

    Objective To investigate the application value of multi-slice spiral CT urography(MSCTU) in the diagnosis of upper urinary tract obstructive disorder. Methods 20 patients with upper urinary tract obstructive disorder treated from July 2008 to June 2012 were performed MSCTU scan. The primary data were performed the three dimensional reconstructions for the comparison with the results of X-ray,B-type ultrasound and IVU. Results 5 cases were developed at 1 h,1 case was postponed to develop at 2 h,3 cases had undeveloped one side and other 11 cases were normally developed. Conclusion MSCTU has the high sensitivity and high specificity,and can clearly display the upper urinary tract lesions,congenital variations and deformities.%目的 探讨多层螺旋CT泌尿系造影(MSCTU)在上尿路梗阻性疾病诊断中的应用价值.方法 选择2008年7月至2012年6月该院收治的上尿路梗阻性疾病20例,行多层螺旋CT扫描,将原始数据三维重建后进行尿路成像,并与X线平片、B超、静脉尿路造影检查结果进行对比分析.结果 5例于1 h显影,1例延迟至2 h显影,3例1侧未显影,其他11例均正常显影.结论 MSCTU是一种无创伤且安全有效的非侵袭性影像检查方法,对上尿路梗阻性疾病的诊断有重要的临床应用价值.

  13. 良、恶性梗阻性黄疸应用多层螺旋CT(MSCT)的临床诊断价值研究%Clinical diagnostic and value study of multi slice spiral CT (MSCT) application for benign and malignant obstructive jaundice

    孙赞江

    2015-01-01

    目的:探讨多层螺旋 CT(MSCT)对于良、恶性梗阻性黄疸的临床诊断价值。方法回顾分析72例梗阻性黄疸患者的临床资料与影像学资料,分析 MSCT 对于梗阻性黄疸的良恶性诊断价值。结果 MSCT 对于梗阻性黄疸的定位诊断准确率为100%,对恶性梗阻性黄疸的诊断准确率为96.43%,对良性梗阻性黄疸的诊断准确率为95.45%。结论MSCT 对于梗阻性黄疸的定位及定性诊断具有较高的准确性,值得在临床中推广应用。%Objective investigate clinical diagnostic value of multi-slice spiral CT (MSCT) for diagnosis of benign and malignant obstructive jaundice. Method analyze and review clinical and imaging data of 72 patients with obstructive jaundice, and analyze diagnostic value of MSCT for benign and malignant obstructive jaundice. Result diagnostic accuracy of MSCT for obstructive jaundice diagnosis is 100%, and for malignant obstructive jaundice is 96.43%, for benign obstructive jaundice is 95.45%. Conclusion MSCT has high accuracy for localization and qualitative diagnosis on obstructive jaundice, which is worthy of being spreaded and applied clinically.

  14. Locality constraints and 2D quasicrystals

    The plausible assumption that long-range interactions between atoms are negligible in a quasicrystal leaks to the study of tilings that obey constraints on the local configurations of tiles. The theory of such constraints (called matching rules) for 2D quasicrystal tilings is reviewed here. Different types of matching rules are defined and examples of tilings obeying them are given where known. The role of tile decoration is discussed and is shown to be significant in at least two cases (octagonal and dodecagonal duals of periodic 4-grids and 6-grids). A new result is introduced: a constructive procedure is described for generating weak matching rules for tilings with N-fold symmetry, for any N that is either a prime number or twice a prime number. The physics associated with weak matching rules, results on local growth rules, and the case of icosahedral symmetry are all briefly discussed. (author). 29 refs, 4 figs

  15. Numerical Evaluation of 2D Ground States

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  16. 2-D Model Test of Dolosse Breakwater

    Burcharth, Hans F.; Liu, Zhou

    1994-01-01

    The rational design diagram for Dolos armour should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) made available such design diagram for the trunk of Dolos breakwater without superstructures (Burcharth et al. 1992). To...... extend the design diagram to cover Dolos breakwaters with superstructure, 2-D model tests of Dolos breakwater with wave wall is included in the project Rubble Mound Breakwater Failure Modes sponsored by the Directorate General XII of the Commission of the European Communities under Contract MAS-CT92......-0042. Furthermore, Task IA will give the design diagram for Tetrapod breakwaters without a superstructure. The more complete research results on Dolosse can certainly give some insight into the behaviour of Tetrapods armour layer of the breakwaters with superstructure. The main part of the experiment was on the...

  17. Graphene suspensions for 2D printing

    Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.

    2016-04-01

    It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).

  18. Area preserving diffeomorphisms and 2-d gravity

    La, H S

    1995-01-01

    Area preserving diffeomorphisms of a 2-d compact Riemannian manifold with or without boundary are studied. We find two classes of decompositions of a Riemannian metric, namely, h- and g-decomposition, that help to formulate a gravitational theory which is area preserving diffeomorphism (SDiffM-) invariant but not necessarily diffeomorphism invariant. The general covariance of equations of motion of such a theory can be achieved by incorporating proper Weyl rescaling. The h-decomposition makes the conformal factor of a metric SDiffM-invariant and the rest of the metric invariant under conformal diffeomorphisms, whilst the g-decomposition makes the conformal factor a SDiffM scalar and the rest a SDiffM tensor. Using these, we reformulate Liouville gravity in SDiffM invariant way. In this context we also further clarify the dual formulation of Liouville gravity introduced by the author before, in which the affine spin connection is dual to the Liouville field.

  19. Metrology for graphene and 2D materials

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  20. MRI (Magnetic Resonance Imaging)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... 8 MB) Also available in Other Language versions . Magnetic Resonance Imaging (MRI) is a medical imaging procedure for making ...

  1. What Is Chest MRI?

    ... from the NHLBI on Twitter. What Is Chest MRI? Chest MRI (magnetic resonance imaging) is a safe, noninvasive test. "Noninvasive" means that ... your chest wall, heart, and blood vessels. Chest MRI uses radio waves, magnets, and a computer to ...

  2. Knee MRI scan

    MRI - knee ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ... less anxious. Your provider may suggest an "open" MRI, in which the machine is not as close ...

  3. MRI visualisation by digitally reconstructed radiographs

    Serrurier, Antoine; Bönsch, Andrea; Lau, Robert; Deserno, Thomas M.

    2015-03-01

    Visualising volumetric medical images such as computed tomography and magnetic resonance imaging (MRI) on picture archiving and communication systems (PACS) clients is often achieved by image browsing in sagittal, coronal or axial views or three-dimensional (3D) rendering. This latter technique requires fine thresholding for MRI. On the other hand, computing virtual radiograph images, also referred to as digitally reconstructed radiographs (DRR), provides in a single two-dimensional (2D) image a complete overview of the 3D data. It appears therefore as a powerful alternative for MRI visualisation and preview in PACS. This study describes a method to compute DRR from T1-weighted MRI. After segmentation of the background, a histogram distribution analysis is performed and each foreground MRI voxel is labeled as one of three tissues: cortical bone, also known as principal absorber of the X-rays, muscle and fat. An intensity level is attributed to each voxel according to the Hounsfield scale, linearly related to the X-ray attenuation coefficient. Each DRR pixel is computed as the accumulation of the new intensities of the MRI dataset along the corresponding X-ray. The method has been tested on 16 T1-weighted MRI sets. Anterior-posterior and lateral DRR have been computed with reasonable qualities and avoiding any manual tissue segmentations. This proof-of-concept holds for research application for use in clinical PACS.

  4. Local 2D-2D tunneling in high mobility electron systems

    Pelliccione, Matthew; Sciambi, Adam; Bartel, John; Goldhaber-Gordon, David; Pfeiffer, Loren; West, Ken; Lilly, Michael; Bank, Seth; Gossard, Arthur

    2012-02-01

    Many scanning probe techniques have been utilized in recent years to measure local properties of high mobility two-dimensional (2D) electron systems in GaAs. However, most techniques lack the ability to tunnel into the buried 2D system and measure local spectroscopic information. We report scanning gate measurements on a bilayer GaAs/AlGaAs heterostructure that allows for a local modulation of tunneling between two 2D electron layers. We call this technique Virtual Scanning Tunneling Microscopy (VSTM) [1,2] as the influence of the scanning gate is analogous to an STM tip, except at a GaAs/AlGaAs interface instead of a surface. We will discuss the spectroscopic capabilities of the technique, and show preliminary results of measurements on a high mobility 2D electron system.[1] A. Sciambi, M. Pelliccione et al., Appl. Phys. Lett. 97, 132103 (2010).[2] A. Sciambi, M. Pelliccione et al., Phys. Rev. B 84, 085301 (2011).

  5. Face recognition method based on 2D-PCA and 2D-LDA%基于2D-PCA和2D-LDA的人脸识别方法

    温福喜; 刘宏伟

    2007-01-01

    提出了基于2D-PCA、2D-LDA两种特征采用融合分类器的人脸识别方法.首先提取人脸图像的2D-PCA和2D-LDA特征,对不同特征在决策层对分类器进行融合.在ORL人脸库上的试验结果表明,分类器决策层融合方法在识别性能上优于2D-PCA和2D-LDA,更具有鲁棒性.

  6. Multi-slice CT pulmonary function evaluation in emphysema

    Objective: To explore the feasibility of evaluating the lung function by MSCT in emphysema. Methods: The MSCT scan and pulmonary function tests (PFT) were respectively performed in 147 receptors within one week. They were randomly divided into 2 groups: group A (120 receptors), including normal, mild, moderate and severe abnormal pulmonary function based on the PFT, for comparing the correlation between pulmonary quantitative indexes of MSCT pulmonary function and PFT and settingup the primary, grade criteria of abnormal pulmonary, function in emphysema, group B (27 receptors) for evaluating the diagnostic accuracy in group A. The total lung was respectively scanned at the full inspiration and full expiration with MSCT. The pulmonary quantitative indexes of MSCT were measured with Siemens Pulmo pulmonary quantitative software. Results: There was correlation between pulmonary quantitative indexes of MSCT and PFT. The Piex/in-910 showed best correlation with FEV1% (r= -0. 905, P-910 (χ20.267, P=0.966, accuracy 81.5%), and the primary criteria for abnormal pulmonary, function of emphysema was normal (0-9.9), mild (10.0-34.9), moderate (35.0-74.9) and severe (≥75.0). Conclusion: It is feasible to evaluate the abnormal lung function of emphysema with pulmonary quantitative indexes of CT. The Piex/in910 was the most effective one in various indexes. (authors)

  7. 3-D Reconstruction From 2-D Radiographic Images and Its Application to Clinical Veterinary Medicine

    Hamamoto, Kazuhiko; Sato, Motoyoshi

    3D imaging technique is very important and indispensable in diagnosis. The main stream of the technique is one in which 3D image is reconstructed from a set of slice images, such as X-ray CT and MRI. However, these systems require large space and high costs. On the other hand, a low cost and small size 3D imaging system is needed in clinical veterinary medicine, for example, in the case of diagnosis in X-ray car or pasture area. We propose a novel 3D imaging technique using 2-D X-ray radiographic images. This system can be realized by cheaper system than X-ray CT and enables to get 3D image in X-ray car or portable X-ray equipment. In this paper, a 3D visualization technique from 2-D radiographic images is proposed and several reconstructions are shown. These reconstructions are evaluated by veterinarians.

  8. 2D DIGITAL SIMPLIFIED FLOW VALVE

    Ruan Jian; Li Sheng; Pei Xiang; Burton R; Ukrainetz P; Bitner D

    2004-01-01

    The 2D digital simplified flow valve is composed of a pilot-operated valve designed with both rotary and linear motions of a single spool,and a stepper motor under continual control.How the structural parameters affect the static and dynamic characteristics of the valve is first clarified and a criterion for stability is presented.Experiments are designed to test the performance of the valve.It is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless,it is possible to maintain the dynamic response at a fairly high level,while keeping the leakage of the pilot stage at an acceptable level.One of the features of the digital valve is stage control.In stage control the nonlinearities,such as electromagnetic saturation and hysteresis,are greatly reduced.To a large extent the dynamic response of the valve is decided by the executing cycle of the control algorithm.

  9. Competing coexisting phases in 2D water

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-05-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules.

  10. 2D manifold-independent spinfoam theory

    A number of background-independent quantization procedures have recently been employed in 4D nonperturbative quantum gravity. We investigate and illustrate these techniques and their relation in the context of a simple 2D topological theory. We discuss canonical quantization, loop or spin network states, path integral quantization over a discretization of the manifold, spin foam formulation and the fully background-independent definition of the theory using an auxiliary field theory on a group manifold. While several of these techniques have already been applied to this theory by Witten, the last one is novel: it allows us to give a precise meaning to the sum over topologies, and to compute background-independent and, in fact, 'manifold-independent' transition amplitudes. These transition amplitudes play the role of Wightman functions of the theory. They are physical observable quantities, and the canonical structure of the theory can be reconstructed from them via a C* algebraic GNS construction. We expect an analogous structure to be relevant in 4D quantum gravity

  11. Ion Transport in 2-D Graphene Nanochannels

    Xie, Quan; Foo, Elbert; Duan, Chuanhua

    2015-11-01

    Graphene membranes have recently attracted wide attention due to its great potential in water desalination and selective molecular sieving. Further developments of these membranes, including enhancing their mass transport rate and/or molecular selectivity, rely on the understanding of fundamental transport mechanisms through graphene membranes, which has not been studied experimentally before due to fabrication and measurement difficulties. Herein we report the fabrication of the basic constituent of graphene membranes, i.e. 2-D single graphene nanochannels (GNCs) and the study of ion transport in these channels. A modified bonding technique was developed to form GNCs with well-defined geometry and uniform channel height. Ion transport in such GNCs was studied using DC conductance measurement. Our preliminary results showed that the ion transport in GNCs is still governed by surface charge at low concentrations (10-6M to 10-4M). However, GNCs exhibits much higher ionic conductances than silica nanochannels with the same geometries in the surface-charge-governed regime. This conductance enhancement can be attributed to the pre-accumulation of charges on graphene surfaces. The work is supported by the Faculty Startup Fund (Boston University, USA).

  12. Phase Engineering of 2D Tin Sulfides.

    Mutlu, Zafer; Wu, Ryan J; Wickramaratne, Darshana; Shahrezaei, Sina; Liu, Chueh; Temiz, Selcuk; Patalano, Andrew; Ozkan, Mihrimah; Lake, Roger K; Mkhoyan, K A; Ozkan, Cengiz S

    2016-06-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2 and orthorhombic tin (II) sulfide SnS crystals with diameters of over tens of microns on SiO2 substrates through atmospheric pressure vapor-phase method in a conventional horizontal quartz tube furnace with SnO2 and S powders as the source materials. Detailed characterization of each phase of tin sulfide crystals is performed using various microscopy and spectroscopy methods, and the results are corroborated by ab initio density functional theory calculations. PMID:27099950

  13. Competing coexisting phases in 2D water.

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-01-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules. PMID:27185018

  14. Resolution Independent 2D Cartoon Video Conversion

    MSF. Fayaza

    2016-03-01

    Full Text Available This paper describes a novel system for vectorizing 2D raster cartoon. The output videos are the resolution independent, smaller in file size. As a first step, input video is segment to scene thereafter all processes are done for each scene separately. Every scene contains foreground and background objects so in each and every scene foreground background classification is performed. Background details can occlude by foreground objects but when foreground objects move its previous position such occluded details exposed in one of the next frame so using that frame can fill the occluded area and can generate static background. Classified foreground objects are identified and the motion of the foreground objects tracked for this simple user assistance is required from those motion details of foreground object’s animation generated. Static background and foreground objects segmented using K-means clustering and each and every cluster’s vectorized using potrace. Using vectored background and foreground object animation path vector video regenerated.

  15. Identification of novel CYP2D7-2D6 hybrids: non-functional and functional variants

    Andrea Gaedigk

    2010-10-01

    Full Text Available Polymorphic expression of CYP2D6 contributes to the wide range of activity observed for this clinically important drug metabolizing enzyme. In this report we describe novel CYP2D7/2D6 hybrid genes encoding non-functional and functional CYP2D6 protein and a CYP2D7 variant that mimics a CYP2D7/2D6 hybrid gene. Five kb long PCR products encompassing the novel genes were entirely sequenced. A quantitative assay probing in different gene regions was employed to determine CYP2D6 and 2D7 copy number variations and the relative position of the hybrid genes within the locus was assessed by long-range PCR. In addition to the previously known CYP2D6*13 and *66 hybrids, we describe three novel non-functional CYP2D7-2D6 hybrids with gene switching in exon 2 (CYP2D6*79, intron 2 (CYP2D6*80 and intron 5 (CYP2D6*67. A CYP2D7-specific T-ins in exon 1 causes a detrimental frame shift. One subject revealed a CYP2D7 conversion in the 5’-flanking region of a CYP2D6*35 allele, was otherwise unaffected (designated CYP2D6*35B. Finally, three DNAs revealed a CYP2D7 gene with a CYP2D6-like region downstream of exon 9 (designated CYP2D7[REP6]. Quantitative copy number determination, sequence analyses and long-range PCR mapping were in agreement and excluded the presence of additional gene units. Undetected hybrid genes may cause over-estimation of CYP2D6 activity (CYP2D6*1/*1 vs *1/hybrid, etc, but may also cause results that may interfere with the genotype determination. Detection of hybrid events, ‘single’ and tandem, will contribute to more accurate phenotype prediction from genotype data.

  16. Finite state models of constrained 2d data

    Justesen, Jørn

    2004-01-01

    This paper considers a class of discrete finite alphabet 2D fields that can be characterized using tools front finite state machines and Markov chains. These fields have several properties that greatly simplify the analysis of 2D coding methods.......This paper considers a class of discrete finite alphabet 2D fields that can be characterized using tools front finite state machines and Markov chains. These fields have several properties that greatly simplify the analysis of 2D coding methods....

  17. Ultrasonic 2D matrix PVDF transducer

    Ptchelintsev, A.; Maev, R. Gr.

    2000-05-01

    During the past decade a substantial amount of work has been done in the area of ultrasonic imaging technology using 2D arrays. The main problems arising for the two-dimensional matrix transducers at megahertz frequencies are small size and huge count of the elements, high electrical impedance, low sensitivity, bad SNR and slower data acquisition rate. The major technological difficulty remains the high density of the interconnect. To solve these problems numerous approaches have been suggested. In the present work, a 24×24 elements (24 transmit+24 receive) matrix and a switching board were developed. The transducer consists of two 52 μm PVDF layers each representing a linear array of 24 elements placed one on the top of the other. Electrodes in these two layers are perpendicular and form the grid of 0.5×0.5 mm pitch. The layers are bonded together with the ground electrode being monolithic and located between the layers. The matrix is backed from the rear surface with an epoxy composition. During the emission, a linear element from the emitting layer generates a longitudinal wave pulse propagating inside the test object. Reflected pulses are picked-up by the receiving layer. During one transmit-receive cycle one transmit element and one receive element are selected by corresponding multiplexers. These crossed elements emulate a small element formed by their intersection. The present design presents the following advantages: minimizes number of active channels and density of the interconnect; reduces the electrical impedance of the element improving electrical matching; enables the transmit-receive mode; due to the efficient backing provides bandwidth and good time resolution; and, significantly reduces the electronics complexity. The matrix can not be used for the beam steering and focusing. Owing to this impossibility of focusing, the penetration depth is limited as well by the diffraction phenomena.

  18. Magnetic Resonance Imaging (MRI)

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ... Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of safe, painless testing ...

  19. Polynomial solution of 2D Kalman-Bucy filtering problem

    Sebek, M.

    1992-01-01

    The 2D version of the Kalman-Bucy filtering problem is formulated and then solved via 2D polynomial methods. The optimal filter is restricted to be a linear causal system. The design procedure is shown to consist of one 2D spectral factorization equation only. In fact, it works for n-D signals (n>2)

  20. Polynomial solution of 2D Kalman-Bucy filtering problem

    Sebek, M.

    1992-01-01

    The 2D version of the Kalman-Bucy filtering problem is formulated and then solved via 2D polynomial methods. The optimal filter is restricted to be a linear causal system. The design procedure is shown to consist of one 2D spectral factorization equation only. In fact, it works for n-D signals (n>2) as well.

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

    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

  2. FEM-2D, 2-D MultiGroup Diffusion in X-Y Geometry

    1 - Nature of physical problem solved: FEM-2D solves the two-dimensional diffusion equation in x-y geometry. This is done by the finite elements method. 2 - Method of solution: FEM-2D uses triangular elements with first and second order Lagrange approximations. The systems equations are formulated in multigroup form and solved by Cholesky procedure which operates only on nonzero elements. Various acceleration techniques are available for the outer iteration. Fluxes along various lines and rates in arbitrary zones may be output. 3 - Restrictions on the complexity of the problem: The code uses variable dimensioning. Thus, the problem size is restricted by the largest array which usually is the systems matrix. Fluxes of all groups are kept in memory. This might become another restrictive data set for a large number of groups. The validity of the results is restricted by the approximations used. FEM-2D requires a finite element net which allows the approximation of fluxes by at most parabolas. The node distribution should be more dense in areas of heavy flux changes (near absorbers or the reflector)

  3. DNTM/R2D, 2-D Transport in X-Y Geometry

    1 - Description of program or function: DNTM/R2D solves the neutron transport equation in two-dimensional X-Y geometry by the discrete nodal transport method. Source and eigenvalue problems can be solved. As compared to the two-dimensional nodal transport code DNTM/2D, the following new improved features are included: - Anisotropic scattering is considered. The order of anisotropic scattering is from P0 to P3. - The cross section input format is the same as for ANISN. Multi- group cross section libraries such as DLC-37 and DLC-BUGLE-80 can be used. 2 - Method of solution: DNTM/R2D uses the discrete nodal transport method. Anisotropic scattering is treated using Legendre expansion. Order of interior flux approximation is 2. Plane leakage approximation of surface flux is used. 3 - Restrictions on the complexity of the problem: Maximum number of: anisotropic scattering order = 3; material composition = 20; energy groups = 2; angular quadrature = 8; zones = 30. When coarse-mesh re-balancing is used, the maximum number of coarse meshes is 12 in each direction. If the computer permits some arrays can be enlarged to reduce the above restrictions

  4. State-of-the-art MRI techniques in neuroradiology: principles, pitfalls, and clinical applications

    This article reviews the most relevant state-of-the-art magnetic resonance (MR) techniques, which are clinically available to investigate brain diseases. MR acquisition techniques addressed include notably diffusion imaging (diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI)) as well as perfusion imaging (dynamic susceptibility contrast (DSC), arterial spin labeling (ASL), and dynamic contrast enhanced (DCE)). The underlying models used to process these images are described, as well as the theoretic underpinnings of quantitative diffusion and perfusion MR imaging-based methods. The technical requirements and how they may help to understand, classify, or follow-up neurological pathologies are briefly summarized. Techniques, principles, advantages but also intrinsic limitations, typical artifacts, and alternative solutions developed to overcome them are discussed. In this article, we also review routinely available three-dimensional (3D) techniques in neuro MRI, including state-of-the-art and emerging angiography sequences, and briefly introduce more recently proposed 3D quantitative neuro-anatomy sequences, and new technology, such as multi-slice and multi-transmit imaging. (orig.)

  5. State-of-the-art MRI techniques in neuroradiology: principles, pitfalls, and clinical applications

    Viallon, Magalie [Universite de Lyon, CREATIS, UMR CNRS 5220 - INSERM U1044, INSA de Lyon, Lyon (France); Universite de Lyon-Saint-Etienne, Department of Radiology, Centre Hospitalier Universitaire de Saint-Etienne, Saint Etienne (France); Cuvinciuc, Victor; Barnaure-Nachbar, Isabelle; Lovblad, Karl-Olof; Haller, Sven [University Hospital of Geneva, Department of Neuroradiology, Geneva (Switzerland); Delattre, Benedicte; Toso-Patel, Seema; Becker, Minerva [University Hospital of Geneva, Department of Radiology, Geneva (Switzerland); Merlini, Laura [University Hospital of Geneva, Department of Pediatric Radiology, Geneva (Switzerland)

    2015-05-01

    This article reviews the most relevant state-of-the-art magnetic resonance (MR) techniques, which are clinically available to investigate brain diseases. MR acquisition techniques addressed include notably diffusion imaging (diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI)) as well as perfusion imaging (dynamic susceptibility contrast (DSC), arterial spin labeling (ASL), and dynamic contrast enhanced (DCE)). The underlying models used to process these images are described, as well as the theoretic underpinnings of quantitative diffusion and perfusion MR imaging-based methods. The technical requirements and how they may help to understand, classify, or follow-up neurological pathologies are briefly summarized. Techniques, principles, advantages but also intrinsic limitations, typical artifacts, and alternative solutions developed to overcome them are discussed. In this article, we also review routinely available three-dimensional (3D) techniques in neuro MRI, including state-of-the-art and emerging angiography sequences, and briefly introduce more recently proposed 3D quantitative neuro-anatomy sequences, and new technology, such as multi-slice and multi-transmit imaging. (orig.)

  6. In vivo confirmation of hydration based contrast mechanisms for terahertz medical imaging using MRI

    Bajwa, Neha; Sung, Shijun; Garritano, James; Nowroozi, Bryan; Tewari, Priyamvada; Ennis, Daniel B.; Alger, Jeffery; Grundfest, Warren; Taylor, Zachary

    2014-09-01

    Terahertz (THz) detection has been proposed and applied to a variety of medical imaging applications in view of its unrivaled hydration profiling capabilities. Variations in tissue dielectric function have been demonstrated at THz frequencies to generate high contrast imagery of tissue, however, the source of image contrast remains to be verified using a modality with a comparable sensing scheme. To investigate the primary contrast mechanism, a pilot comparison study was performed in a burn wound rat model, widely known to create detectable gradients in tissue hydration through both injured and surrounding tissue. Parallel T2 weighted multi slice multi echo (T2w MSME) 7T Magnetic Resonance (MR) scans and THz surface reflectance maps were acquired of a full thickness skin burn in a rat model over a 5 hour time period. A comparison of uninjured and injured regions in the full thickness burn demonstrates a 3-fold increase in average T2 relaxation times and a 15% increase in average THz reflectivity, respectively. These results support the sensitivity and specificity of MRI for measuring in vivo burn tissue water content and the use of this modality to verify and understand the hydration sensing capabilities of THz imaging for acute assessments of the onset and evolution of diseases that affect the skin. A starting point for more sophisticated in vivo studies, this preliminary analysis may be used in the future to explore how and to what extent the release of unbound water affects imaging contrast in THz burn sensing.

  7. Stability Test for 2-D Continuous-Discrete Systems

    2002-01-01

    Models of 2-D continuous-discrete systems are introduced, which can be used to describe some complex systems. Different from classical 2-D continuous systems or 2-D discrete systems, the asymptotic stability of the continuous-discrete systems is determined by Hurwitz-Schur stability (hybrid one) of 2-D characteristic polynomials of the systems. An algebraic algorithm with simpler test procedure for Hurwitz-Schur stability test of 2-D polynomials is developed. An example to illustrate the applications of the test approach is provided.

  8. Correlated Electron Phenomena in 2D Materials

    Lambert, Joseph G.

    In this thesis, I present experimental results on coherent electron phenomena in layered two-dimensional materials: single layer graphene and van der Waals coupled 2D TiSe2. Graphene is a two-dimensional single-atom thick sheet of carbon atoms first derived from bulk graphite by the mechanical exfoliation technique in 2004. Low-energy charge carriers in graphene behave like massless Dirac fermions, and their density can be easily tuned between electron-rich and hole-rich quasiparticles with electrostatic gating techniques. The sharp interfaces between regions of different carrier densities form barriers with selective transmission, making them behave as partially reflecting mirrors. When two of these interfaces are set at a separation distance within the phase coherence length of the carriers, they form an electronic version of a Fabry-Perot cavity. I present measurements and analysis of multiple Fabry-Perot modes in graphene with parallel electrodes spaced a few hundred nanometers apart. Transition metal dichalcogenide (TMD) TiSe2 is part of the family of materials that coined the term "materials beyond graphene". It contains van der Waals coupled trilayer stacks of Se-Ti-Se. Many TMD materials exhibit a host of interesting correlated electronic phases. In particular, TiSe2 exhibits chiral charge density waves (CDW) below TCDW ˜ 200 K. Upon doping with copper, the CDW state gets suppressed with Cu concentration, and CuxTiSe2 becomes superconducting with critical temperature of T c = 4.15 K. There is still much debate over the mechanisms governing the coexistence of the two correlated electronic phases---CDW and superconductivity. I will present some of the first conductance spectroscopy measurements of proximity coupled superconductor-CDW systems. Measurements reveal a proximity-induced critical current at the Nb-TiSe2 interfaces, suggesting pair correlations in the pure TiSe2. The results indicate that superconducting order is present concurrently with CDW in

  9. CYP2D7 sequence variation interferes with TaqMan CYP2D6*15 and *35 genotyping

    Amanda K Riffel

    2016-01-01

    Full Text Available TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35 which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696 SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe

  10. Nonrigid registration of myocardial perfusion MRI

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrigid...... registration algorithm based on free-form deformations due to Rueckert et al. Inspection of difference images from the wash-out part of the perfusion sequences indicates that a good registration accuracy is obtained....

  11. Nonrigid registration of myocardial perfusion MRI

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrigid registration algorithm based on free-form deformations due to Rueckert et al. Inspection of difference images from the wash-out part of the perfusion sequences indicates that a good registration ac...

  12. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis

    Shaheen, Eman, E-mail: eman.shaheen@uzleuven.be; De Keyzer, Frederik; Bosmans, Hilde; Ongeval, Chantal Van [Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); Dance, David R.; Young, Kenneth C. [National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford GU2 7XX, United Kingdom and Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2014-08-15

    Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly

  13. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis

    Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly

  14. Development and Assessment of a New 3D Neuroanatomy Teaching Tool for MRI Training

    Drapkin, Zachary A.; Lindgren, Kristen A.; Lopez, Michael J.; Stabio, Maureen E.

    2015-01-01

    A computerized three-dimensional (3D) neuroanatomy teaching tool was developed for training medical students to identify subcortical structures on a magnetic resonance imaging (MRI) series of the human brain. This program allows the user to transition rapidly between two-dimensional (2D) MRI slices, 3D object composites, and a combined model in…

  15. Functional characterization of a first avian cytochrome P450 of the CYP2D subfamily (CYP2D49.

    Hua Cai

    Full Text Available The CYP2D family members are instrumental in the metabolism of 20-25% of commonly prescribed drugs. Although many CYP2D isoforms have been well characterized in other animal models, research concerning the chicken CYP2Ds is limited. In this study, a cDNA encoding a novel CYP2D enzyme (CYP2D49 was cloned from the chicken liver for the first time. The CYP2D49 cDNA contained an open reading frame of 502 amino acids that shared 52%-57% identities with other CYP2Ds. The gene structure and neighboring genes of CYP2D49 are conserved and similar to those of human CYP2D6. Additionally, similar to human CYP2D6, CYP2D49 is un-inducible in the liver and expressed predominantly in the liver, kidney and small intestine, with detectable levels in several other tissues. Metabolic assays of the CYP2D49 protein heterologously expressed in E. coli and Hela cells indicated that CYP2D49 metabolized the human CYP2D6 substrate, bufuralol, but not debrisoquine. Moreover, quinidine, a potent inhibitor of human CYP2D6, only inhibited the bufuralol 1'-hydroxylation activity of CYP2D49 to a negligible degree. All these results indicated that CYP2D49 had functional characteristics similar to those of human CYP2D6 but measurably differed in the debrisoquine 4'-hydroxylation and quinidine inhibitory profile. Further structure-function investigations that employed site-directed mutagenesis and circular dichroism spectroscopy identified the importance of Val-126, Glu-222, Asp-306, Phe-486 and Phe-488 in keeping the enzymatic activity of CYP2D49 toward bufuralol as well as the importance of Asp-306, Phe-486 and Phe-488 in maintaining the conformation of CYP2D49 protein. The current study is only the first step in characterizing the metabolic mechanism of CYP2D49; further studies are still required.

  16. MAZE, Input Generator for Program DYNA2D and NIKE2D

    Description of program or function: MAZE is an interactive input generator for two-dimensional finite element codes. MAZE has three phases. In the first phase, lines and parts are defined. The first phase is terminated by the 'ASSM' or 'PASSM' command which merges all parts. In the second phase, boundary conditions may be specified, slide-lines may be defined, parts may be merged to eliminate nodes along common interfaces, boundary nodes may be moved for graded zoning, the mesh may be smoothed, and load curves may be defined. The second phase is terminated by the 'WBCD' command which causes MAZE to write the output file as soon as the 'T' terminate command is typed. In the third phase, material properties may be defined. Commands that apply to the first phase may not be used in the second or third; likewise, commands that apply in the second may not be used in the first and third, or commands that apply in the third in the first and second. Nine commands - TV, Z, GSET, PLOTS, GRID, NOGRID, FRAME, NOFRAME, and RJET are available in all phases. Comments may be added anywhere in the input stream by prefacing the comment with 'C'. Any DYNA2D or NIKE2D material and equation-of- state model may be defined via the MAT and EOS commands respectively. Maze may be terminated after phase two; it is not necessary to define the materials

  17. Surface Approximation Using the 2D FFENN Architecture

    Panagopoulos S

    2004-01-01

    Full Text Available A new two-dimensional feed-forward functionally expanded neural network (2D FFENN used to produce surface models in two dimensions is presented. New nonlinear multilevel surface basis functions are proposed for the network's functional expansion. A network optimization technique based on an iterative function selection strategy is also described. Comparative simulation results for surface mappings generated by the 2D FFENN, multilevel 2D FFENN, multilayered perceptron (MLP, and radial basis function (RBF architectures are presented.

  18. Maximizing entropy of image models for 2-D constrained coding

    Forchhammer, Søren; Danieli, Matteo; Burini, Nino; Zamarin, Marco; Ukhanova, Ann

    2010-01-01

    This paper considers estimating and maximizing the entropy of two-dimensional (2-D) fields with application to 2-D constrained coding. We consider Markov random fields (MRF), which have a non-causal description, and the special case of Pickard random fields (PRF). The PRF are 2-D causal finite context models, which define stationary probability distributions on finite rectangles and thus allow for calculation of the entropy. We consider two binary constraints and revisit the hard square const...

  19. Magnetic Resonance Imaging (MRI) Safety

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining very ...

  20. Maximizing entropy of image models for 2-D constrained coding

    Forchhammer, Søren; Danieli, Matteo; Burini, Nino;

    2010-01-01

    This paper considers estimating and maximizing the entropy of two-dimensional (2-D) fields with application to 2-D constrained coding. We consider Markov random fields (MRF), which have a non-causal description, and the special case of Pickard random fields (PRF). The PRF are 2-D causal finite...... of the Markov random field defined by the 2-D constraint is estimated to be (upper bounded by) 0.8570 bits/symbol using the iterative technique of Belief Propagation on 2 £ 2 finite lattices. Based on combinatorial bounding techniques the maximum entropy for the constraint was determined to be 0.848....

  1. Interventional MRI: update

    Lufkin, R.B. [Department of Radiology, University of California Los Angeles, School of Medicine, 10 833 Le Comte Avenue, Los Angeles, CA 90024-1721 (United States); Gronemeyer, D.H.W.; Seibel, R.M.M. [Institute of Diagnostic and Interventional Radiology, Medical Computerscience, University Witten/Herdecke (Germany)

    1997-12-31

    Interventional MRI is in its early stages of development. Nevertheless, the design of new interventional MRI scanners that allow maximum direct access to the patient combined with the development of new interventional MRI pulse sequences and localization systems, means that the archetypal operating rooms of the 21st century may well contain dedicated interventional MRI units for combined radiological and surgical procedures. The present article looks at the state of interventional MRI today and looks ahead to what may be forthcoming in the not-too-distant future. After briefly discussing the instrumentation necessary for practical interventional MRI, the article will go on to describe a number of different approaches to, and clinical applications for, interventional MRI. The use of MRI in guiding and controlling tumor ablation, aspiration cytology and surgical biopsy of different body parts is described. (orig.) With 13 figs., 1 tab., 114 refs.

  2. Abdominal MRI scan

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ...

  3. Klassifikation von Standardebenen in der 2D-Echokardiographie mittels 2D-3D-Bildregistrierung

    Bergmeir, Christoph; Subramanian, Navneeth

    Zum Zweck der Entwicklung eines Systems, das einen unerfahrenen Anwender von Ultraschall (US) zur Aufnahme relevanter anatomischer Strukturen leitet, untersuchen wir die Machbarkeit von 2D-US zu 3D-CT Registrierung. Wir verwenden US-Aufnahmen von Standardebenen des Herzens, welche zu einem 3D-CT-Modell registriert werden. Unser Algorithmus unterzieht sowohl die US-Bilder als auch den CT-Datensatz Vorverarbeitungsschritten, welche die Daten durch Segmentierung auf wesentliche Informationen in Form von Labein für Muskel und Blut reduzieren. Anschließend werden diese Label zur Registrierung mittels der Match-Cardinality-Metrik genutzt. Durch mehrmaliges Registrieren mit verschiedenen Initialisierungen ermitteln wir die im US-Bild sichtbare Standardebene. Wir evaluierten die Methode auf sieben US-Bildern von Standardebenen. Fünf davon wurden korrekt zugeordnet.

  4. 2D Four-Channel Perfect Reconstruction Filter Bank Realized with the 2D Lattice Filter Structure

    Sezen S

    2006-01-01

    Full Text Available A novel orthogonal 2D lattice structure is incorporated into the design of a nonseparable 2D four-channel perfect reconstruction filter bank. The proposed filter bank is obtained by using the polyphase decomposition technique which requires the design of an orthogonal 2D lattice filter. Due to constraint of perfect reconstruction, each stage of this lattice filter bank is simply parameterized by two coefficients. The perfect reconstruction property is satisfied regardless of the actual values of these parameters and of the number of the lattice stages. It is also shown that a separable 2D four-channel perfect reconstruction lattice filter bank can be constructed from the 1D lattice filter and that this is a special case of the proposed 2D lattice filter bank under certain conditions. The perfect reconstruction property of the proposed 2D lattice filter approach is verified by computer simulations.

  5. MRI of Stroke Recovery

    Jiang, Quan; Zhang, Zheng Gang; Chopp, Michael

    2009-01-01

    MRI is a vital tool for the measurement of acute stroke and has been used to visualize changes in activation patterns during stroke recovery. There is emerging interest on using MRI to monitor the structural substrates of spontaneous recovery and neurorestorative treatment of stroke. In this review, we describe the use of MRI and its associated challenges to measure vascular and neuronal remodeling in response to spontaneous and therapy-induced stroke recovery. We demonstrate that MRI methodo...

  6. MRI in cranial tuberculosis

    Just, M.; Higer, H.P.; Betting, O.; Bockenheimer, S.; Pfannenstiel, P.

    1987-11-01

    A case of multiple intracranial tuberculomas is presented. CT and MRI findings are discussed and compared. MRI showed multiple tuberculomas characterised by the same signal intensity as the surrounding brain parenchyma. Differentiation could be achieved only by the perifocal oedema of the high signal intensity. Changes of the lesions during chemotherapy were monitored by CT and MRI and the results are presented. (orig.)

  7. MRI in cranial tuberculosis.

    Just, M; Higer, H P; Betting, O; Bockenheimer, S; Pfannenstiel, P

    1987-11-01

    A case of multiple intracranial tuberculomas is presented. CT and MRI findings are discussed and compared. MRI showed multiple tuberculomas characterised by the same signal intensity as the surrounding brain parenchyma. Differentiation could be achieved only by the perifocal oedema of high signal intensity. Changes of the lesions during chemotherapy were monitored by CT and MRI and the results are presented. PMID:3691545

  8. fMRI Neuroinformatics

    Nielsen, Finn Årup; Christensen, Mark Schram; Madsen, Kristoffer M.;

    2006-01-01

    Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction...

  9. MRI in acute poliomyelitis

    Kornreich, L. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Dagan, O. [The Intensive Care Unit, The Schneider Children`s Medical Centre of Israel, Beilinson Medical Campus, Petah Tiqva (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Grunebaum, M. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    1996-05-01

    MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig.

  10. Getting an MRI

    ... Snowboarding, Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A Text Size en ... Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed pictures of ...

  11. Getting an MRI

    Full Text Available ... Snowboarding, Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A Text Size en ... Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed pictures of ...

  12. Getting an MRI

    Full Text Available ... Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A Text Size en español Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed ...

  13. 多层螺旋 CT 灌注成像在脑胶质瘤分级中的价值与微血管密度的相关性研究%Application value of multi-slice spiral CT perfusion imaging in brain gliomas and its relation with microvessel density

    洪建斌; 许乃滔; 侯志雄

    2014-01-01

    Objective To study the value of multi-slice spiral CT (MSCT ) perfusion imaging in grading of brain glioma(BG) and its correlation with microvessel density (MVD) .Methods A total of 89 BG patients ,treated in this hospital from March 2010 to March 2013 ,were enrolled and divided into high grade group and low grade group , according to the grading levels .MSCT parameters and MVD ,vascular endothelial growth factor(VEGF) levels were compared ,and the correlation between relative cerebral blood flow (rCBV) and MVD ,VEGF were analyzed .Results Levels of cerebral blood flow (CBF) ,rCBF ,cerebral blood volume(CBV) ,relative CBV(rCBV) of high grade group were significantly higher than low grade group (P< 0 .05) .The positive rate of VEGF in high grade group was 89 .13% (41/46) ,higher than the 55 .81% (24/43) of low grade group(P<0 .05) .Level of MVD in high grade group was 70 .76 ± 8 .85 ,significantly higher than the 37 .75 ± 5 .65 of low grade group(P<0 .05) .rCBV level was positive-ly correlated with MVD and VEGF expression level (r= 0 .610 and r= 0 .631 ,P< 0 .05) .Conclusion rCBV level could be positively correlated with MVD and VEGF expression level in patients wit BG .MSCT could provide fine im-aging evidence for the grading of BG .%目的:研究多层螺旋CT(MSCT)灌注成像在脑胶质瘤(BG)分级中的价值与微血管密度(MVD)的相关性。方法选择该院2010年3月至2013年3月诊治的89例BG患者作为观察对象,根据BG分级标准分成高级别组以及低级别组。对比两组MSCT参数以及MVD、血管内皮生长因子(VEGF);分析相对脑血容量(rCBV)和MVD、VEGF的相关性。结果高级别组的脑血流量(CBF)、相对脑血流量(rCBF)、脑血容量(CBV)、rCBV均明显高于低级别组;高级别组VEGF阳性率为89.13%(41/46),明显高于低级别组的55.81%(24/43);高级别组MVD为70.76±8.85,明显高于低级别组的37.75±5.65,差

  14. 多层螺旋CT及多维重建技术对隐匿性肋骨骨折的诊断价值探讨%Study of the multi-slice CT and for multi-dimensional reconstruction techniques the diagnosis of occult rib fracture

    蔡洪涛

    2014-01-01

    目的:考察多层螺旋CT(MSCT)联合多维重建技术对隐匿性肋骨骨折的临床诊断价值,为该类疾病临床诊断提供参考。方法:以我院2012年7月至2014年2月间收治的73例隐匿性肋骨骨折患者为研究对象,使用MSCT联合VR、SSD、CRP等多种重建技术对患者进行检查,统计并分析影像学检查结果。结果:73例患者经MSCT检查确诊隐匿性肋骨骨折107处,骨折多发于肋骨角(59.81%)且以非完全线性骨折为主(91.59%)。所用多维重建技术的诊断精度依次为:CRP(100.0%)>MPR(97.19%)>SSD(85.89%)>VR(78.50%)>MIP(27.88%)。结论:MSCT联合多维重建技术对隐匿性肋骨骨折具有较为明确的诊断价值,MSCT与CRP/MPR及VR等联用可获得较为理想的诊断率。%Objective:To investigate the clinical value of the multi-slice CT and for multi-dimensional reconstruction techniques the diagnosis of occult rib fracture, to provide a reference for the diagnosis of occult rib fracture.Methods:73 cases patients with occult rib fracture which received treatment during 2012.07 to 2014. 02, were the objects for this study, used MSCT joint VR, SSD, CRP and other reconstruction techniques to detected the occult rib fracture of all the patients, and then the imaging results of the patients were analyzed. Results:The results of MSCT showed 107 occult rib fracture were detected for 73 cases patients, and about 59.81% occult rib fracture were occurred in the rib angle, and the non- fully linear fracture dominated 91.59%. The diagnostic accuracy of all the multi-dimensional reconstruction techniques used in this study were: CRP (100.0%)> MPR (97.19%)>SSD (85.89%)> VR (78.50%)> MIP (27.88%).Conclusions:The MSCT joint multi-dimensional reconstruction techniques has a speciifc diagnostic value for the occult rib fractures, MSCT combined with MSCT CRP / MPR and VR, etc. could received a ideal diagnostic accuracy.

  15. ROC分析在多层螺旋CT综合性诊断孤立性肺结节良恶性中的应用%Role of ROC analysis in comprehensive diagnosis to differentiate malignant from benign solitary pulmonary nodules with multi-slice spiral CT

    杨玉海; 邵广瑞; 宋磊; 张伟

    2011-01-01

    Objective To study the role of receiver operating characteristic (ROC) analysis in comprehensive diagnosis to differentiate malignant from benign solitary pulmonary nodules (SPNs) with multi-slice spiral computed tomography (MSCT).Methods 177 SPNs were examined with MSCT and pathologically confirmed by surgery and/or needle biopsy.All MSCT images were assessed and graded by three senior radiologists on the basis of malignant likelihood of morphological and density characteristics.According to the maximum diameter (D), ROC curves were constructed and optimal thresholds were determined for diagnosis of malignancy in SPNS of D≤3.0 cm, 2.0 cm < D≤3.0 cm and D≤2.0 cm.ROC analysis was used to evaluate the efficiency of MSCT in differentiating malignant from benign SPNs.The area under the ROC curve ( Az ) was used as an index for diagnostic efficiency with MSCT.Az values were statistically analyzed by Z-test.Results A, values of ROC curves were 0.879 ± 0.030 in SPNs of D ≤3.0 cm, 0.899 ± 0.039 in SPNs of 2.0 cm < D≤3.0 cm and 0.867 ± 0.044 in SPNs of D≤2.0 cm.The differences were statistically significant according to the Z-test ( P < 0.05).The three optimal thresholds for diagnosis of malignancy were 3.0, 3.5 and 2.5.Conclusion Application of ROC analysis is of obvious value in the differential diagnosis of SPNs with comprehensive imaging characteristics obtained by MSCT.It is favorable to combine the diagnosis of SPNs by MSCT with the malignant probability and to improve the treatment of SPNs in clinical practice.%目的 探讨在孤立性肺结节(SPN)良恶性的多层螺旋CT(MSCT)综合性诊断中ROC分析的应用价值.方法 经手术和/或穿刺活检组织病理结果 证实的SPN 177个,由3位资深的CT诊断医师分别对每个SPN的MSCT图像进行全面分析,依其影像特征进行综合评分,根据SPN的最大径(D),以MSCT评分为分类值,分别绘制D≤3.0 cm、2.0 cm<D≤3.0 cm和D≤2.0 cm SPN良恶性诊断的ROC曲

  16. Multi-slice CT evaluation of glenoid bone loss in patients with recurrent anterior shoulder dislocation%多层螺旋CT评价复发性肩关节前方脱位的前方关节盂骨质缺损的临床意义

    崔志新; 张悦; 郑卓肇; 任阿红

    2012-01-01

    目的 在复发性肩关节前方脱位中,利用MSCT评估关节盂前方骨质缺损情况.方法 回顾分析108例复发性肩关节前脱位和12例单次肩关节脱位患者的MSCT检查,对比评价前方关节盂骨质缺损的发生率、程度及位置.利用Fisher精确概率法分析前方关节盂骨质缺损的发生率,利用Wilcoxon秩和检验比较前方关节盂骨质缺损的上下长径、深度及比例.结果 在复发性肩关节前脱位中,91.7%(99/108)存在前方关节盂的骨质缺损,缺损比例为(16.0±6.0)%,缺损中心位置介于时钟分区的2:20~ 4:25点(平均3:20点),62.0%(67/108)前方出现骨性Bankart病变,包括游离型39例(58.2%)及黏附型28例(41.8%).12例单次肩关节脱位中,9例出现前方关节盂骨质缺损,其缺损发生率(9/12;P=0.100)和缺损比例[(15.2±7.1)%;P=0.453]与复发性肩关节脱位比较差异均无统计学意义.结论 前方关节盂骨质缺损为复发性肩关节前方脱位的常见表现.%Objective To evaluate multi-slice CT (MSCT) in glenoid bone loss of patients with recurrent anterior shoulder dislocation.Methods MSCT findings of 108 patients with recurrent anterior shoulder dislocation and 12 with single anterior shoulder dislocation were retrospectively studied.The incidence,degrees and locations of glenoid bone losses were recorded.The incidence was analyzed with Fisher exact test.The maximum length,depth and proportion were compared with Wilcoxon rank sum test.Results Glenoid bone loss was detected in 91.7% (99/108)patients with recurrent anterior shoulder dislocation.The proportion of glenoid bone loss was ( 16.0 ± 6.0)%,and the central locations of glenoid bone loss were from 2: 20 to 4: 25 ( mean 3: 20).Sixty-two percent (67/108) patients had bony Bankart lesions in which 58.2% (39/67) bony fragments were free and 41.8% (28/67) were adherent to the anterior border of the glenoid cavity.Seventy-five percent (9/12) patients with single

  17. 多层螺旋CT在儿童完全性肺静脉异位引流诊断中的研究%Application of multi-slice spiral CT in diagnosis of total anomalous pulmonary venous drainage in children

    樊国峰; 赵鑫; 张小安; 叶自青; 刘晓晨

    2011-01-01

    目的:探讨多层螺旋CT在完全性肺静脉异位引流中的诊断价值.方法:回顾性分析2005年5月~2010年4月经心脏外科手术证实的30例完全性肺静脉异位引流患儿的MSCT图像特点,探讨MSCT在完全性肺静脉异位引流及并发畸形诊断中的价值,为术前诊断、手术方式选择及术后随访提供信息.结果:30例中心上型15例,心内型12例,心下型2例,混合型1例;术前经MSCT诊断为完全型28例(心上型15例,心内型10例,心下型2例,混合型1例),漏诊2例,诊断符合率为93.3%;TTE诊断心上型11例,心内型9例,心下型1例,漏诊9例,诊断符合率为70.0%.结论:多层螺旋CT.是完全性肺静脉异位引流准确、重要的检查方法.%Objective: To explore the value of multi - slice spiral CT (MSCT) in diagnosis of total anomalous pulmonary venous drainnge (TAPVD) in children.Methods: The imaging characteristics of MSCT among 30 children with TAPVD who were diagnosed definitely by department of cardiac surgery in the hospital from May 2005 to April 2010 were analyzed retrospectively, the value of MSCT in diagnosis of TAPVD combined with abnormality was explored, then the information was provided for preoperative dingnosis, choice of operative medes and postoperative follow -up.Results: The types of TAPVD among 30 children: 15 children with supra - cardiac type, 12 children with intra- cardiac type, 2 children with infra- cardiac type and 1 child with mixed type; 28 children were diagnosed as complete type by MSCT before surgery ( 15 children with supra -cardiac type, 10 children with intra -cardiac type, 2 children with infra -cardiac type and 1 child with mixed type), 2 children were missed, the diagnostic accordance rate was 93.3%.The results of TTE: 11 children with supra -cardiac type, 9 children with intra- cardiac type, 1 child with infra -cardiac type, 9 children were missed, the diagnostic accordance rate was 70.0%.Conclusion: MSCT is a accurate and important

  18. Value of combining 64 multi-slice spiral computer tomography and serum amyloid A protein in surgical decision-making in rectal cancer%多层螺旋CT联合血清淀粉样蛋白A术前评估直肠癌在外科决策中的价值

    汪晓东; 吕东昊; 宋欢; 秦昌龙; 吴俊华; 李臻辉; 李立

    2009-01-01

    目的 探讨64排多层螺旋CT(MSCT)和血清淀粉样蛋白A(SAA)联合术前评估进行直肠癌术前分期的准确性及其临床应用价值.方法 前瞻性纳入2007年10月至2008年10月期间住院的225例直肠癌患者,将患者随机分为MSCT组和MSCT与SAA联合组,联合组术前行MSCT和SAA联合评估,MSCT组术前只行MSCT评估.分别将两组术前T、N、M、TNM分期准确度进行比较,并比较两组手术方案的预测符合率.结果 本研究实际纳入病例225例,MSCT和SAA联合组110例,MSCT组115例,两组基线情况具有可比性.联合组术前T、N、M和TNM分期的准确度分别为87.3%、85.2%、100%和86.4%,MSCT组的准确度分别为85.2%、67.0%、100%和66.1%;两组术前N分期和TNM分期准确度差异具有统计学意义(P=0.009、0.001).两组手术方案的预测符合率分别为94.7%和81.7%,差异具有统计学意义(P=0.003).结论 MSCT和SAA联合评估的策略可以提高直肠癌患者术前分期N、TNM的准确性,并可提高预测手术方案的符合率.%Objective To determine the accuracy and clinical value of combining 64 multi-slice spiral computer tomography (MSCT) and serum amyloid A protein (SAA) in the preoperative staging of rectal cancer.Methods Prospectively enrolled patients with rectal cancer from October 2007 to October 2008.The patients were randomly assigned into two groups:MSCT and SAA combined group:both MSCT and SAA combinative assessment were performed for preoperative evaluation; MSCT group:only MSCT was performed preoperatively for tumor staging.The accuracy of the preoperative T,N,M,and TNM staging and the concordance rate of predictive operative strategy were compared between the two groups.Results Total of 225 cases with rectal cancer were enrolled in this study.There were 110 cases in MSCT and SAA combined group and 115 cases in MSCT group.The baseline characteristics was comparable between the two groups.For MSCT and SAA combined group,the accuracies of

  19. An Incompressible 2D Didactic Model with Singularity and Explicit Solutions of the 2D Boussinesq Equations

    Chae, Dongho; Constantin, Peter; Wu, Jiahong

    2014-09-01

    We give an example of a well posed, finite energy, 2D incompressible active scalar equation with the same scaling as the surface quasi-geostrophic equation and prove that it can produce finite time singularities. In spite of its simplicity, this seems to be the first such example. Further, we construct explicit solutions of the 2D Boussinesq equations whose gradients grow exponentially in time for all time. In addition, we introduce a variant of the 2D Boussinesq equations which is perhaps a more faithful companion of the 3D axisymmetric Euler equations than the usual 2D Boussinesq equations.

  20. Symmetries and solvable models for evaporating 2D black holes

    Cruz Muñoz, José Luis; Navarro-Salas, José; Navarro Navarro, Miguel; Talavera, C. F.

    1997-01-01

    We study the evaporation process of a 2D black hole in thermal equilibrium when the ingoing radiation is suddenly switched off. We also introduce global symmetries of generic 2D dilaton gravity models which generalize the extra symmetry of the CGHS model. © Elsevier Science B.V

  1. Cascading Constrained 2-D Arrays using Periodic Merging Arrays

    Forchhammer, Søren; Laursen, Torben Vaarby

    2003-01-01

    We consider a method for designing 2-D constrained codes by cascading finite width arrays using predefined finite width periodic merging arrays. This provides a constructive lower bound on the capacity of the 2-D constrained code. Examples include symmetric RLL and density constrained codes....... Numerical results for the capacities are presented....

  2. 2D gravity, random surfaces and all that

    I review the recent progress in 2d gravity and discuss the new numerical simulations for 2d gravity and for random surfaces in d>2. The random surface theories of interest in d>2 have extrinsic curvature terms, and for a finite value of the extrinsic curvature coupling there seems to be a second order phase transition where the string tension scales. (orig.)

  3. Van der Waals stacked 2D layered materials for optoelectronics

    Zhang, Wenjing; Wang, Qixing; Chen, Yu; Wang, Zhuo; Wee, Andrew T. S.

    2016-06-01

    The band gaps of many atomically thin 2D layered materials such as graphene, black phosphorus, monolayer semiconducting transition metal dichalcogenides and hBN range from 0 to 6 eV. These isolated atomic planes can be reassembled into hybrid heterostructures made layer by layer in a precisely chosen sequence. Thus, the electronic properties of 2D materials can be engineered by van der Waals stacking, and the interlayer coupling can be tuned, which opens up avenues for creating new material systems with rich functionalities and novel physical properties. Early studies suggest that van der Waals stacked 2D materials work exceptionally well, dramatically enriching the optoelectronics applications of 2D materials. Here we review recent progress in van der Waals stacked 2D materials, and discuss their potential applications in optoelectronics.

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

    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.)

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

    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.)

  6. DYNA-2D, 2-D Hydrodynamic Finite Elements Method Program with Interactive Rezoning

    1 - Description of program or function: DYNA2D is an explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. A contact-impact algorithm permits gaps and sliding with friction along material interfaces. By a specialization of this algorithm, such interfaces can be rigidly tied to admit variable zoning with no need for transition regions. Spatial discretization is achieved by the use of 4-node solid elements, and the equations-of-motion are integrated by the central difference method. The material models implemented are: elastic, orthotropic elastic, kinematic/isotropic elastic-plastic, thermo- elastic-plastic, soil and crushable foam, linear visco-elastic, rubber, isotropic elastic-plastic, and temperature-dependent elastic-plastic. The latter two models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state. 2 - Restrictions on the complexity of the problem - Maxima of: 60,000 elements (Cray 1), 5,000 elements (CDC7600)

  7. Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide.

    Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng

    2016-08-01

    Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples. PMID:27378648

  8. 2D vs. 3D mammography observer study

    Fernandez, James Reza F.; Hovanessian-Larsen, Linda; Liu, Brent

    2011-03-01

    Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using a mammography phantom was performed to compare traditional 2D mammography with this ne 3D mammography technique. In comparing 3D and 2D mammography there was no difference in calcification detection, and mass detection was better in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Given the limitations of the mammography phantom used, however, a clearer picture in comparing 3D and 2D mammography may be better acquired with the incorporation of human studies in the future.

  9. In-vivo quantification of wall motion in cerebral aneurysms from 2D cine phase contrast magnetic resonance images

    Karmonik, C. [The Methodist Hospital Research Inst., Houston (United States); Diaz, O.; Klucznik, R. [The Methodist Hospital, Houston (United States); Grossman, R. [The Methodist Hospital, Houston (United States). Neurosurgery

    2010-02-15

    Purpose: The quantification of wall motion in cerebral aneurysms is of interest for the assessment of aneurysmal rupture risk, for providing boundary conditions for computational simulations and as a validation tool for theoretical models. Materials and Methods: 2D cine phase contrast magnetic resonance imaging (2D pcMRI) in combination with quantitative magnetic resonance angiography (QMRA) was evaluated for measuring wall motion in 7 intracranial aneurysms. In each aneurysm, 2 (in one case 3) cross sections, oriented approximately perpendicular to each other, were measured. Results: The maximum aneurysmal wall distention ranged from 0.16 mm to 1.6 mm (mean 0.67 mm), the maximum aneurysmal wall contraction was -1.91 mm to -0.34 mm (mean 0.94 mm), and the average wall displacement ranged from 0.04 mm to 0.31 mm (mean 0.15 mm). Statistically significant correlations between average wall displacement and the shape of inflow curves (p-value < 0.05) were found in 7 of 15 cross sections; statistically significant correlations between the displacement of the luminal boundary center point and the shape of inflow curves (p-value < 0.05) were found in 6 of 15 cross sections. Conclusion: 2D pcMRI in combination with QMRA is capable of visualizing and quantifying wall motion in cerebral aneurysms. However, application of this technique is currently restricted by its limited spatial resolution. (orig.)

  10. In-vivo quantification of wall motion in cerebral aneurysms from 2D cine phase contrast magnetic resonance images

    Purpose: The quantification of wall motion in cerebral aneurysms is of interest for the assessment of aneurysmal rupture risk, for providing boundary conditions for computational simulations and as a validation tool for theoretical models. Materials and Methods: 2D cine phase contrast magnetic resonance imaging (2D pcMRI) in combination with quantitative magnetic resonance angiography (QMRA) was evaluated for measuring wall motion in 7 intracranial aneurysms. In each aneurysm, 2 (in one case 3) cross sections, oriented approximately perpendicular to each other, were measured. Results: The maximum aneurysmal wall distention ranged from 0.16 mm to 1.6 mm (mean 0.67 mm), the maximum aneurysmal wall contraction was -1.91 mm to -0.34 mm (mean 0.94 mm), and the average wall displacement ranged from 0.04 mm to 0.31 mm (mean 0.15 mm). Statistically significant correlations between average wall displacement and the shape of inflow curves (p-value < 0.05) were found in 7 of 15 cross sections; statistically significant correlations between the displacement of the luminal boundary center point and the shape of inflow curves (p-value < 0.05) were found in 6 of 15 cross sections. Conclusion: 2D pcMRI in combination with QMRA is capable of visualizing and quantifying wall motion in cerebral aneurysms. However, application of this technique is currently restricted by its limited spatial resolution. (orig.)

  11. The NH$_2$D hyperfine structure revealed by astrophysical observations

    Daniel, F.; Coudert, L. H.; Punanova, A.; Harju, J.; Faure, A.; Roueff, E.; Sipilä, O.; Caselli, P.; Güsten, R.; Pon, A.; Pineda, J E

    2016-01-01

    The 1$_{11}$-1$_{01}$ lines of ortho and para--NH$_2$D (o/p-NH$_2$D), respectively at 86 and 110 GHz, are commonly observed to provide constraints on the deuterium fractionation in the interstellar medium. In cold regions, the hyperfine structure due to the nitrogen ($^{14}$N) nucleus is resolved. To date, this splitting is the only one which is taken into account in the NH$_2$D column density estimates. We investigate how the inclusion of the hyperfine splitting caused by the deuterium (D) n...

  12. Materials for Flexible, Stretchable Electronics: Graphene and 2D Materials

    Kim, Sang Jin; Choi, Kyoungjun; Lee, Bora; Kim, Yuna; Hong, Byung Hee

    2015-07-01

    Recently, 2D materials have been intensively studied as emerging materials for future electronics, including flexible electronics, photonics, and electrochemical energy storage devices. Among representative 2D materials (such as graphene, boron nitride, and transition metal dichalcogenides) that exhibit extraordinary properties, graphene stands out in the flexible electronics field due to its combination of high electron mobility, high thermal conductivity, high specific surface area, high optical transparency, excellent mechanical flexibility, and environmental stability. This review covers the synthesis, transfer, and characterization methods of graphene and 2D materials and graphene's application to flexible devices as well as comparison with other competing materials.

  13. Introduction to game physics with Box2D

    Parberry, Ian

    2013-01-01

    Written by a pioneer of game development in academia, Introduction to Game Physics with Box2D covers the theory and practice of 2D game physics in a relaxed and entertaining yet instructional style. It offers a cohesive treatment of the topics and code involved in programming the physics for 2D video games. Focusing on writing elementary game physics code, the first half of the book helps you grasp the challenges of programming game physics from scratch, without libraries or outside help. It examines the mathematical foundation of game physics and illustrates how it is applied in practice thro

  14. Comparison of 2D and 3D gamma analyses

    Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F., E-mail: sfkry@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Bosca, Ryan [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); O’Daniel, Jennifer [Department of Radiation Oncology, Duke University, Durham, North Carolina 27705 (United States)

    2014-02-15

    Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must

  15. Optimization and practical implementation of ultrafast 2D NMR experiments

    Luiz H. K. Queiroz Júnior

    2013-01-01

    Full Text Available Ultrafast 2D NMR is a powerful methodology that allows recording of a 2D NMR spectrum in a fraction of second. However, due to the numerous non-conventional parameters involved in this methodology its implementation is no trivial task. Here, an optimized experimental protocol is carefully described to ensure efficient implementation of ultrafast NMR. The ultrafast spectra resulting from this implementation are presented based on the example of two widely used 2D NMR experiments, COSY and HSQC, obtained in 0.2 s and 41 s, respectively.

  16. Optimization and practical implementation of ultrafast 2D NMR experiments

    Queiroz Junior, Luiz H. K., E-mail: professorkeng@gmail.com [Universidade Federal de Sao Carlos (UFSC), SP (Brazil). Departamento de Quimica; Universidade Federal de Goias (UFGO), Goiania, GO (Brazil). Inst. de Quimica; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSC), SP (Brazil). Departamento de Quimica; Giraudeau, Patrick [Universite de Nantes (France). CNRS, Chimie et Interdisciplinarite: Synthese, Analyse, Modelisation

    2013-09-01

    Ultrafast 2D NMR is a powerful methodology that allows recording of a 2D NMR spectrum in a fraction of second. However, due to the numerous non-conventional parameters involved in this methodology its implementation is no trivial task. Here, an optimized experimental protocol is carefully described to ensure efficient implementation of ultrafast NMR. The ultrafast spectra resulting from this implementation are presented based on the example of two widely used 2D NMR experiments, COSY and HSQC, obtained in 0.2 s and 41 s, respectively. (author)

  17. Kalman Filter for Generalized 2-D Roesser Models

    SHENG Mei; ZOU Yun

    2007-01-01

    The design problem of the state filter for the generalized stochastic 2-D Roesser models, which appears when both the state and measurement are simultaneously subjected to the interference from white noise, is discussed. The wellknown Kalman filter design is extended to the generalized 2-D Roesser models. Based on the method of "scanning line by line", the filtering problem of generalized 2-D Roesser models with mode-energy reconstruction is solved. The formula of the optimal filtering, which minimizes the variance of the estimation error of the state vectors, is derived. The validity of the designed filter is verified by the calculation steps and the examples are introduced.

  18. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited)

    Classen, I. G. J. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Boom, J. E.; Vries, P. C. de [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr. [University of California at Davis, Davis, California 95616 (United States); Donne, A. J. H. [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Jaspers, R. J. E. [Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Park, H. K. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Munsat, T. [University of Colorado, Boulder, Colorado 80309 (United States)

    2010-10-15

    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.

  19. 3D reconstruction of femoral shape using a two 2D radiographs and statistical parametric model

    In medical imaging, X-ray CT scanner or MRI system are quite useful to acquire 3D shapes of internal organs or bones. However, these apparatuses are generally very expensive and of large size. They also need a prior arrangement, and thus, they are unsuitable for an urgent fracture diagnosis in emergency treatment. This paper proposes a method to estimate a 3D shape of patient's femur from only two radiographs using a parametric femoral model. Firstly, we develop the parametric femoral model utilizing statistical procedure of 3D femoral models by CT images of 51 patients. Then, the pose and shape parameters of the parametric model are estimated from two 2D images using a distance map constructed by the Level Set Method. Experiments using synthesized images and radiographs of a phantom femur are carried out to verify the performance of the proposed technique. (author)

  20. A software tool for automatic classification and segmentation of 2D/3D medical images

    Modern medical diagnosis utilizes techniques of visualization of human internal organs (CT, MRI) or of its metabolism (PET). However, evaluation of acquired images made by human experts is usually subjective and qualitative only. Quantitative analysis of MR data, including tissue classification and segmentation, is necessary to perform e.g. attenuation compensation, motion detection, and correction of partial volume effect in PET images, acquired with PET/MR scanners. This article presents briefly a MaZda software package, which supports 2D and 3D medical image analysis aiming at quantification of image texture. MaZda implements procedures for evaluation, selection and extraction of highly discriminative texture attributes combined with various classification, visualization and segmentation tools. Examples of MaZda application in medical studies are also provided

  1. SALE-2D, 2-D Fluid Flow, Navier Stokes Equation Using Lagrangian or Eulerian Method

    1 - Description of problem or function: SALE2D calculates two- dimensional fluid flows at all speeds, from the incompressible limit to highly supersonic. An implicit treatment of the pressure calculation similar to that in the Implicit Continuous-fluid Eulerian (ICE) technique provides this flow speed flexibility. In addition, the computing mesh may move with the fluid in a typical Lagrangian fashion, be held fixed in an Eulerian manner, or move in some arbitrarily specified way to provide a continuous rezoning capability. This latitude results from use of an Arbitrary Lagrangian-Eulerian (ALE) treatment of the mesh. The partial differential equations solved are the Navier-Stokes equations and the mass and internal energy equations. The fluid pressure is determined from an equation of state and supplemented with an artificial viscous pressure for the computation of shock waves. The computing mesh consists of a two-dimensional network of quadrilateral cells for either cylindrical or Cartesian coordinates, and a variety of user-selectable boundary conditions are provided in the program. 2 - Method of solution: The basic hydrodynamic part of each cycle of SALE is divided into three phases. Phase 1 is a typical explicit Lagrangian calculation in which the velocity field is updated by the effects of all forces. Phase 2 is a Newton-Raphson iteration that provides time-advanced pressures and velocities. It is used for calculations in the low-speed and even completely incompressible regimes. Phase 3 performs all the advective flux calculations. It is required for runs that are Eulerian or contain some other form of mesh rezoning. A powerful feature of SALE is the ease with which different phases can be combined to suit the requirements of individual problems

  2. Measurement of femoral torsion and tibial torsion using magnetic resonance imaging (MRI)

    A new MRI method for the measurement of femoral torsion and tibial torsion is presented. Axial images were generated using a standard gradient echo sequence (FLASH 2D). Otherwise measurement of femoral and tibial torsion was performed according to an established CT method. The torsion angles measured using MRI were in accordance with the angles measured using the CT method. The MRI method was not more time-consuming than the CT method. In respect of radiation exposure, MRI determination of femoral and tibial torsion should be considered particularly in children and patients who have to undergo repeated torsion measurements. (orig.)

  3. Technical Review of the UNET2D Hydraulic Model

    Perkins, William A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Richmond, Marshall C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2009-05-18

    The Kansas City District of the US Army Corps of Engineers is engaged in a broad range of river management projects that require knowledge of spatially-varied hydraulic conditions such as velocities and water surface elevations. This information is needed to design new structures, improve existing operations, and assess aquatic habitat. Two-dimensional (2D) depth-averaged numerical hydraulic models are a common tool that can be used to provide velocity and depth information. Kansas City District is currently using a specific 2D model, UNET2D, that has been developed to meet the needs of their river engineering applications. This report documents a tech- nical review of UNET2D.

  4. Illumination Compensation for 2-D Barcode Recognition Basing Morphologic

    Jian-Hua Li

    2013-04-01

    Full Text Available Improvement of image quality has been highly demanded in digital imaging systems. This study presents a novel illumination normalization approach for 2-D barcode recognition under varying lighting conditions. MMs (Morphological transformations are employed to original images using big scale multiple SEs (structuring elements. Then we make use of entropy to fuse images. The performance of proposed methodology is illustrated through the processing of images with different kinds of 2-D barcodes under different backgrounds. The experimental results show that this approach can process different kinds of 2-D barcodes under varying lighting conditions adaptively. Compared with other conventional methods, our proposed approach does a better job in processing 2-D barcode under non-uniform illumination.

  5. Recent developments in 2D layered inorganic nanomaterials for sensing

    Kannan, Padmanathan Karthick; Late, Dattatray J.; Morgan, Hywel; Rout, Chandra Sekhar

    2015-08-01

    Two dimensional layered inorganic nanomaterials (2D-LINs) have recently attracted huge interest because of their unique thickness dependent physical and chemical properties and potential technological applications. The properties of these layered materials can be tuned via both physical and chemical processes. Some 2D layered inorganic nanomaterials like MoS2, WS2 and SnS2 have been recently developed and employed in various applications, including new sensors because of their layer-dependent electrical properties. This article presents a comprehensive overview of recent developments in the application of 2D layered inorganic nanomaterials as sensors. Some of the salient features of 2D materials for different sensing applications are discussed, including gas sensing, electrochemical sensing, SERS and biosensing, SERS sensing and photodetection. The working principles of the sensors are also discussed together with examples.

  6. Chemical vapour deposition: Transition metal carbides go 2D

    Gogotsi, Yury

    2015-11-01

    The unique properties of 2D materials, such as graphene or transition metal dichalcogenides, have been attracting much attention in the past decade. Now, metallically conductive and even superconducting transition metal carbides are entering the game.

  7. 2d quantum gravity and black hole formation

    The quantum integral of generic 2d quantum gravity can be performed exactly. The equivalence of dilaton theories to 2d theories with torsion and the use of a light cone gauge are crucial. Scalar matter can be treated perturbatively. A generalization of the Polyakov action emerges. For scattering of scalars in a flat background already in the tree approximation for the first time the intermediate formation of a black hole is observed in an ab initio quantum gravity computation

  8. Sparse Non-negative Matrix Factor 2-D Deconvolution

    Mørup, Morten; Schmidt, Mikkel N.

    2006-01-01

    We introduce the non-negative matrix factor 2-D deconvolution (NMF2D) model, which decomposes a matrix into a 2-dimensional convolution of two factor matrices. This model is an extension of the non-negative matrix factor deconvolution (NMFD) recently introduced by Smaragdis (2004). We derive and ...... this form of factorization. The developed algorithms have been used for source separation and music transcription....

  9. Excitation of 2D plasmons in Cs/W(110)

    Benemanskaya, G V; Frank-Kamenetskaya, G E

    2001-01-01

    One studied the evolution of surface photoemission spectra for Cs/W(110) system at metastable Cs coatings exceeding monolayer. One showed possibility to observe 2D plasmons by means of threshold photoemission spectroscopy. One detected three photoemission peaks characterized by complicated behavior depending on Cd adsorption dose. The nature of peaks may be related to plasmon photoinduced excitation in quasi-2D Cs clusters, surface Cs plasmon and interface Cs-W plasmon

  10. QSAR Models for P-450 (2D6) Substrate Activity

    Ringsted, Tine; Nikolov, Nikolai Georgiev; Jensen, Gunde Egeskov;

    2009-01-01

    activity relationship (QSAR) modelling systems. They cross validated (leave-groups-out) with concordances of 71%, 81% and 82%, respectively. Discrete organic European Inventory of Existing Commercial Chemical Substances (EINECS) chemicals were screened to predict an approximate percentage of CYP 2D6...... substrates. These chemicals are potentially present in the environment. The biological importance of the CYP 2D6 and the use of the software mentioned above were discussed....

  11. The Branching of Graphs in 2-d Quantum Gravity

    Harris, M. G.

    1996-01-01

    The branching ratio is calculated for three different models of 2d gravity, using dynamical planar phi-cubed graphs. These models are pure gravity, the D=-2 Gaussian model coupled to gravity and the single spin Ising model coupled to gravity. The ratio gives a measure of how branched the graphs dominating the partition function are. Hence it can be used to estimate the location of the branched polymer phase for the multiple Ising model coupled to 2d gravity.

  12. Illumination Compensation for 2-D Barcode Recognition Basing Morphologic

    Jian-Hua Li; Yi-Wen Wang; Yi Chen; Meng Zhang

    2013-01-01

    Improvement of image quality has been highly demanded in digital imaging systems. This study presents a novel illumination normalization approach for 2-D barcode recognition under varying lighting conditions. MMs (Morphological transformations) are employed to original images using big scale multiple SEs (structuring elements). Then we make use of entropy to fuse images. The performance of proposed methodology is illustrated through the processing of images with different kinds of 2-D barcode...

  13. The relation between Euclidean and Lorentzian 2D quantum gravity

    Ambjørn, J.; Correia, J; Kristjansen, C.; Loll, R.

    2006-01-01

    Starting from 2D Euclidean quantum gravity, we show that one recovers 2D Lorentzian quantum gravity by removing all baby universes. Using a peeling procedure to decompose the discrete, triangulated geometries along a one-dimensional path, we explicitly associate with each Euclidean space-time a (generalized) Lorentzian spacetime. This motivates a map between the parameter spaces of the two theories, under which their propagators get identified. In two dimensions, Lorentzian quantum gravity ca...

  14. MRI in psychiatry

    Mulert, Christoph [UKE, Hamburg (Germany). Psychiatry Neuroimaging Branch; Shenton, Martha E. (ed.) [Harvard Medical School, Boston, MA (United States). Dept. of Psychiatry and Radiology

    2014-07-01

    This is the first comprehensive textbook on the use of MRI in psychiatry covering imaging techniques, brain systems and a review of findings in different psychiatric disorders. The book is divided into three sections, the first of which covers in detail all the major MRI-based methodological approaches available today, including fMRI, EEG-fMRI, DTI, and MR spectroscopy. In addition, the role of MRI in imaging genetics and combined brain stimulation and imaging is carefully explained. The second section provides an overview of the different brain systems that are relevant for psychiatric disorders, including the systems for perception, emotion, cognition, and reward. The final part of the book presents the MRI findings that are obtained in all the major psychiatric disorders using the previously discussed techniques. Numerous carefully chosen images support the informative text, making this an ideal reference work for all practitioners and trainees with an interest in this flourishing field.

  15. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  16. Abdominal MRI in childhood

    MRI provides diagnostic information in multiple abdominal diseases in childhood. Additional information to sonographic findings can be achieved in the diagnosis of abdominal malformation as well as in several inflammatory processes. In childhood cancer imaging MRI is essential at the beginning as well as during therapy to assess response to therapy. Because of radiation protection MRI has to replace CT in abdominal imaging in children. Some technical details have to be considered when children are examined. (orig.)

  17. MRI of adrenal masses

    The diagnostic usefulness of MRI was evaluated on 38 adrenal masses. The most important finding differentiating adenomas from metastases was the size of the tumor and the signal intensity of the mass. Adenomas showed a tendency to be smaller and homogeneous in signal intensity. On MRI with Gd-DTPA adenomas also showed moderate homogeneous enhancement, but metastases were inhomogeneously enhanced. The detectability by MRI was almost comparable with CT. Three cases of small adenomas and hyperplasia 1-1.5 cm in diameter were detectable only with CT. MRI seems to be complementary to CT in the diagnosis of adrenal masses. (author)

  18. MRI assessment program

    Usage, cost and efficacy data from the MRI Assessment Program to 30 March 1988 is presented, as a continuation of an earlier analysis. Analysis has been performed on data from 8565 examinations relating to 7997 patients at 4 hospitals. MRI was used mainly for examination of the head and spine. Some details of the follow up studies being conducted on selected patients and disease categories are given. A consensus statement is included which summaries the view of the Technical Committee on the potential applications of MRI in Australia. The MRI unit quench incident at Royal Adelaide Hospital is described. Refs., 10 figs., tabs

  19. Use of inflammatory factors combined with multi-slice spiral computer tomography for preoperative staging and operative strategy in colon cancer%三种不同炎性因子联合多层螺旋CT对结肠癌术前分期与术式预测的比较研究

    汪晓东; 欧阳书睿; 吕东昊; 刘丹; 李立

    2010-01-01

    Objective To determine the clinical value of C-reactive protein(CRP), fibrinogen (FIB), or serum amyloid A protein (SAA) combined with 64 multi-slice computed tomography (MSCT) for preoperative staging and operative strategy in colon cancer. Methods Patients with colon cancer were prospectively enrolled at the West China Hospital of Sichuan University from November 2007 to July 2009,and were equally randomized into 3 groups undergoing different preoperative evaluation: MSCT combined with CRP(CRP group), MSCT combined with FIB (FIB group), and MSCT combined with SAA (SAA group). The agreement between preoperative staging and postoperative pathologic staging and that between expected surgical procedure and procedure adopted were compared. Results Baseline characteristics among three groups were similar(P>0.05). In CRP group, the accuracies of preoperative staging T, N, M and TNM were 65.7%, 72.4%, 100% and 66.7%, respectively. In FIB group, the accuracies of preoperative staging T, N, M and TNM were 71.4%, 74.3%, 99.0% and 65.7%, respectively. In SAA group, the accuracies of preoperative staging T, N, M and TNM were 60.0%, 55.2%, 96.2%and 51.4%, respectively. The accuracies of N and TNM staging in CRP group and FIB group were significantly higher than those in SAA group(P<0.05). However, there were no significant differences between FIB and CRP group(P>0.05). There were no significant differences in accuracy of predicting surgical procedures among three groups(93.3%, 92.3% and 87.6%, P>0.05). Conclusion Combined assessment of MSCT and CRP or FIB may improve the accuracy of preoperative staging and procedure prediction, and is superior to MSCT combined with SAA.%目的 探讨纤维蛋白原(FIB)、血清淀粉样蛋白(SAA)和C反应蛋白(CRP)联合64排多层螺旋CT(MSCT)在结肠癌术前评估与术式预测中的临床价值.方法 前瞻性纳入2007年11月至2009年7月期间四川大学华西医院结直肠外科专业组

  20. Determination of left ventricular heart volume by fast MRI in breath-hold technique: how different are quantitative ventricular angiography, quantitative MRI, and visual echocardiography?

    Goal: Comparison of fast MRI, echocardiography (Echo), and ventricular angiography (Cath) in the assessment of left ventricular global function. Methods: Fast MRI in short axis plane, biplane Cath, and 2D Echo were performed in 62 patients [35 coronary artery diseases, 16 acquired valvular diseases (VD), 9 dilated cardiomyopathies (DCM), 1 congenital heart disease and 1 heart transplantation]. Enddiastolic (EDV), endsystolic (ESV), stroke volumes (SV), cardiac output (CO), and ejection fraction (EF) were compared in MRI and Cath. EF was visually estimated in 2D Echo by an experienced observer. Results: In comparison to MRI, Cath overestimated EF by 8.4%, and Echo underestimated EF by 5.6%. The limits of agreement between MRI and Cath in EF were ±23.8%, between MRI and Echo ±18%, and between Echo and Cath ±19.4%. Significant differences were found between Cath and MRI in EDV, SV, and CO, but not for ESV. The best agreement in EF was found in the group with DCM, the worst in the group with VD. Conclusion: Important systemic and random errors were found in the comparison of MRI, Echo, and Cath. For therapy decision and follow-up, the methods should not be exchanged unscrupulously. (orig.)

  1. MRI for the evaluation of pectus excavatum

    Pectus excavatum, the most common congenital deformity of the anterior chest wall, is both a cosmetic and functional abnormality. The degree of abnormal chest wall deformity determines its functional effect, particularly its cardiac and pulmonary impact. Although CT scanning is the most widely used cross-sectional imaging technique used to measure the Haller index, the radiation exposure is reason to seek other alternatives. At our institution, we have introduced a rapid MRI technique for this purpose, which utilizes a single-axial 2-D FIESTA acquisition. (orig.)

  2. MRI for the evaluation of pectus excavatum

    Marcovici, Peter A. [University of California, San Diego, Department of Radiology, San Diego, CA (United States); LoSasso, Barry E. [Children' s Hospital and Health Center, Department of Surgery, San Diego, CA (United States); Kruk, Peter; Dwek, Jerry R. [Children' s Hospital and Health Center, Department of Radiology, San Diego, CA (United States)

    2011-06-15

    Pectus excavatum, the most common congenital deformity of the anterior chest wall, is both a cosmetic and functional abnormality. The degree of abnormal chest wall deformity determines its functional effect, particularly its cardiac and pulmonary impact. Although CT scanning is the most widely used cross-sectional imaging technique used to measure the Haller index, the radiation exposure is reason to seek other alternatives. At our institution, we have introduced a rapid MRI technique for this purpose, which utilizes a single-axial 2-D FIESTA acquisition. (orig.)

  3. Sparse Non-negative Tensor 2D Deconvolution (SNTF2D) for multi channel time-frequency analysis

    Mørup, Morten; Schmidt, Mikkel N.

    2006-01-01

    We recently introduced two algorithms for sparse non-negative matrix factor 2-D deconvolution (SNMF2D) that are useful for single channel source separation and music transcription. We here extend this approach to the analysis of the log-frequency spectrograms of a multichannel recording. The model...... algorithms are demonstrated to successfully identify the components of both artificially generated as well as real stereo music....

  4. MRI simulation: end-to-end testing for prostate radiation therapy using geometric pelvic MRI phantoms

    Sun, Jidi; Dowling, Jason; Pichler, Peter; Menk, Fred; Rivest-Henault, David; Lambert, Jonathan; Parker, Joel; Arm, Jameen; Best, Leah; Martin, Jarad; Denham, James W.; Greer, Peter B.

    2015-04-01

    To clinically implement MRI simulation or MRI-alone treatment planning requires comprehensive end-to-end testing to ensure an accurate process. The purpose of this study was to design and build a geometric phantom simulating a human male pelvis that is suitable for both CT and MRI scanning and use it to test geometric and dosimetric aspects of MRI simulation including treatment planning and digitally reconstructed radiograph (DRR) generation. A liquid filled pelvic shaped phantom with simulated pelvic organs was scanned in a 3T MRI simulator with dedicated radiotherapy couch-top, laser bridge and pelvic coil mounts. A second phantom with the same external shape but with an internal distortion grid was used to quantify the distortion of the MR image. Both phantoms were also CT scanned as the gold-standard for both geometry and dosimetry. Deformable image registration was used to quantify the MR distortion. Dose comparison was made using a seven-field IMRT plan developed on the CT scan with the fluences copied to the MR image and recalculated using bulk electron densities. Without correction the maximum distortion of the MR compared with the CT scan was 7.5 mm across the pelvis, while this was reduced to 2.6 and 1.7 mm by the vendor’s 2D and 3D correction algorithms, respectively. Within the locations of the internal organs of interest, the distortion was phantom allows end-to-end testing of the MRI simulation workflow with comparison to the gold-standard CT based process. MRI simulation was found to be geometrically accurate with organ dimensions, dose distributions and DRR based setup within acceptable limits compared to CT.

  5. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  7. The NH$_2$D hyperfine structure revealed by astrophysical observations

    Daniel, F; Punanova, A; Harju, J; Faure, A; Roueff, E; Sipilä, O; Caselli, P; Güsten, R; Pon, A; Pineda, J E

    2016-01-01

    The 1$_{11}$-1$_{01}$ lines of ortho and para--NH$_2$D (o/p-NH$_2$D), respectively at 86 and 110 GHz, are commonly observed to provide constraints on the deuterium fractionation in the interstellar medium. In cold regions, the hyperfine structure due to the nitrogen ($^{14}$N) nucleus is resolved. To date, this splitting is the only one which is taken into account in the NH$_2$D column density estimates. We investigate how the inclusion of the hyperfine splitting caused by the deuterium (D) nucleus affects the analysis of the rotational lines of NH$_2$D. We present 30m IRAM observations of the above mentioned lines, as well as APEX o/p-NH$_2$D observations of the 1$_{01}$-0$_{00}$ lines at 333 GHz. The hyperfine spectra are first analyzed with a line list that only includes the hyperfine splitting due to the $^{14}$N nucleus. We find inconsistencies between the line widths of the 1$_{01}$-0$_{00}$ and 1$_{11}$-1$_{01}$ lines, the latter being larger by a factor of $\\sim$1.6$\\pm0.3$. Such a large difference is...

  8. Failure Mechanism of True 2D Granular Flows

    Nguyen, Cuong T; Fukagawa, R

    2015-01-01

    Most previous experimental investigations of two-dimensional (2D) granular column collapses have been conducted using three-dimensional (3D) granular materials in narrow horizontal channels (i.e., quasi-2D condition). Our recent research on 2D granular column collapses by using 2D granular materials (i.e., aluminum rods) has revealed results that differ markedly from those reported in the literature. We assume a 2D column with an initial height of h0 and initial width of d0, a defined as their ratio (a =h0/d0), a final height of h , and maximum run-out distance of d . The experimental data suggest that for the low a regime (a 0.65), the ratio of a to (d-d0)/d0, h0/h , or d/d0 is expressed by power-law relations. In particular, the following power-function ratios (h0/h=1.42a^2/3 and d/d0=4.30a^0.72) are proposed for every a >0.65. In contrast, the ratio (d-d0)/d0=3.25a^0.96 only holds for 0.651.5. In addition, the influence of ground contact surfaces (hard or soft beds) on the final run-out distance and destru...

  9. Ultrafast 2D NMR: An Emerging Tool in Analytical Spectroscopy

    Giraudeau, Patrick; Frydman, Lucio

    2014-06-01

    Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy is widely used in chemical and biochemical analyses. Multidimensional NMR is also witnessing increased use in quantitative and metabolic screening applications. Conventional 2D NMR experiments, however, are affected by inherently long acquisition durations, arising from their need to sample the frequencies involved along their indirect domains in an incremented, scan-by-scan nature. A decade ago, a so-called ultrafast (UF) approach was proposed, capable of delivering arbitrary 2D NMR spectra involving any kind of homo- or heteronuclear correlation, in a single scan. During the intervening years, the performance of this subsecond 2D NMR methodology has been greatly improved, and UF 2D NMR is rapidly becoming a powerful analytical tool experiencing an expanded scope of applications. This review summarizes the principles and main developments that have contributed to the success of this approach and focuses on applications that have been recently demonstrated in various areas of analytical chemistry—from the real-time monitoring of chemical and biochemical processes, to extensions in hyphenated techniques and in quantitative applications.

  10. KOREAN MOBILE OPERATORS' VALUE MAP FOR LTE D2D

    Taisiya Kim

    2015-04-01

    Full Text Available Managing the wireless data traffic is a main concern for mobile network operators in Information of Things (IoT environment. Long Term Evolution Device to Device (LTE D2D is regarding as a solution for the spectrum problem. It will bring an impact on providers and the whole mobile environment. The main purpose of this study is to analyze the role of key players, who share spectrum with mobile operators, and to present the value map of relationship among Korean mobile operators and other key players in LTE D2D discovery (commercial channel, as complicated relationships of key players are expected. Then, this study suggests scenario for ‘Targeted Advertising’ service of LTE D2D. LTE D2D is early discussion stage and scenario has limitation of specific business model. However, results of this study are significant for the present stage and provide implications for future researches on strategies for LTE D2D environment.

  11. MRI of Listeria rhombencephalitis

    A case of Listeria rhombencephalitis in a patient, who was evaluated by MRI, is reported. MRI shows areas of high signal intensity on T2-weighted images in the rhombencephalon and confirmed the clinical diagnosis of a brainstem affection by Listeria monocytogenes. (orig.)

  12. Play the MRI Game

    ... Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and radio waves are used for getting images of inner organs made of soft tissue, compared to X-ray imaging where you get images of hard tissue, ...

  13. Getting an MRI

    Full Text Available ... School Butterflies? Read This Chloe & Nurb Meet The Brain (Movie) Quiz: Do You Need a Flu Shot? Got Homework? Here's Help White House Lunch Recipes Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) ...

  14. Getting an MRI

    Full Text Available ... Dictionary of Medical Words En Español What Other Kids Are Reading Movie: Digestive System Winter Sports: Sledding, ... a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A ...

  15. 2D materials for photon conversion and nanophotonics

    Tahersima, Mohammad H.; Sorger, Volker J.

    2015-09-01

    The field of two-dimensional (2D) materials has the potential to enable unique applications across a wide range of the electromagnetic spectrum. While 2D-layered materials hold promise for next-generation photon-conversion intrinsic limitations and challenges exist that shall be overcome. Here we discuss the intrinsic limitations as well as application opportunities of this new class of materials, and is sponsored by the NSF program Designing Materials to Revolutionize and Engineer our Future (DMREF) program, which links to the President's Materials Genome Initiative. We present general material-related details for photon conversion, and show that taking advantage of the mechanical flexibility of 2D materials by rolling MoS2/graphene/hexagonal boron nitride stack to a spiral solar cell allows for solar absorption up to 90%.

  16. Graphene based 2D-materials for supercapacitors

    Palaniselvam, Thangavelu; Baek, Jong-Beom

    2015-09-01

    Ever-increasing energy demands and the depletion of fossil fuels are compelling humanity toward the development of suitable electrochemical energy conversion and storage devices to attain a more sustainable society with adequate renewable energy and zero environmental pollution. In this regard, supercapacitors are being contemplated as potential energy storage devices to afford cleaner, environmentally friendly energy. Recently, a great deal of attention has been paid to two-dimensional (2D) nanomaterials, including 2D graphene and its inorganic analogues (transition metal double layer hydroxides, chalcogenides, etc), as potential electrodes for the development of supercapacitors with high electrochemical performance. This review provides an overview of the recent progress in using these graphene-based 2D materials as potential electrodes for supercapacitors. In addition, future research trends including notable challenges and opportunities are also discussed.

  17. Design and Realization of Dynamic Obstacle on URWPSSim2D

    Xiao Chen

    2013-07-01

    Full Text Available Simulation system is charged with the strategy validation and dual team meets, and as the 2-dimensional simulation platform for underwater robotic fish game, URWPGSim2D is the assigned platform for Chinese underwater robot contest and Robot cup underwater program. By now on URWPGSim2D, there is only static obstacles,thus short of changeableness. In order to improve the changeableness and innovation of robotic fish contest, to extend the space for the programming of contest strategy, and to increase the interest, this paper study the design of dynamic obstacles on URWPGSim2D, and design and implement two kinds of dynamic obstacles, which are the evadible dynamic obstacle and the forcing dribbling obstacle.  

  18. CYP2D6 genotype determination in the Danish population

    Brøsen, K; Nielsen, P N; Brusgaard, K;

    1994-01-01

    CYP2D6 genotyping was carried out by XbaI restriction fragment length polymorphism analysis and polymerase chain reaction in 168 healthy Danish volunteers, 77 extensive metabolizers (EM) and 91 poor metabolizers (PM) of sparteine. All EM were genotyped correctly as heterozygous or homozygous for.......11-9.10). The median difference was 0.09 (95% confidence interval: 0.02-0.16). CYP2D6 phenotyping is a promising tool in tailoring the individual dose of tricyclic antidepressants, some neuroleplics and some antiarrhythmics. However if the genotype test could be improved with regard to both sensitivity in PM...... and the ability to predict CYP2D6 activity in EM then it would be of even greater clinical value in therapeutic drug monitoring. Udgivelsesdato: 1994-null...

  19. Statistical mechanics on a 2D-random surface

    Various geometrical models first defined in the Euclidean plane or on a regular lattice have been briefly reviewed, including self-avoiding walks, random walk intersections, percolation and Ising clusters. These systems embody infinite sets of field operators defined in a natural way from the (fractal) geometry of these fluctuating critical systems. Their scaling behavior can be linked to that of associated conformal field theories. These systems can also all be redefined on a random lattice or surface, instead of on a regular 2D lattice. They are then coupled to ''quantum gravity'', and live on the ''world-sheet''. The fact that all their new exponents on a random surface can then be related to those in the usual 2D-plane, although now well known in string theory, is worth publicizing in this Physics in 2D conference. We illustrate it by some exact solutions in the case of polymers and branched polymers (animals) on a random fluid surface. (author)

  20. Effective viscosity of 2D suspensions - Confinement effects

    Peyla, Philippe; Priem, Stephane; Vincent, Doyeux; Farutin, Alexander; Ismail, Mourad

    2014-11-01

    We study the rheology of a sheared 2D suspension of non-Brownian disks in presence of walls. Although, it is of course possible today with modern computers and powerful algorithms to perform direct numerical simulations that fully account for multiparticle 3D interactions, the analysis of the simple case of a 2D suspension, provides valuable insights and helps to understand 3D results. For instance, we examine the role of particle-wall and particle-particle interactions in determining the rheology of confined sheared suspensions. In addition we evaluate the intrinsic viscosity as well as the contribution of hydrodynamic interactions to the dissipation as a function of a wide range of confinements. Thanks to the direct visualisation of the whole 2D Stokes flow, we are able to give a clear interpretation about the rheology of semi-dilute confined suspensions.

  1. S-duality and 2d Topological QFT

    Gadde, Abhijit; Rastelli, Leonardo; Razamat, Shlomo S

    2009-01-01

    We study the superconformal index for the class of N=2 4d superconformal field theories recently introduced by Gaiotto. These theories are defined by compactifying the (2,0) 6d theory on a Riemann surface with punctures. We interpret the index of the 4d theory associated to an n-punctured Riemann surface as the n-point correlation function of a 2d topological QFT living on the surface. Invariance of the index under generalized S-duality transformations (the mapping class group of the Riemann surface) translates into associativity of the operator algebra of the 2d TQFT. In the A_1 case, for which the 4d SCFTs have a Lagrangian realization, the structure constants and metric of the 2d TQFT can be calculated explicitly in terms of elliptic gamma functions. Associativity then holds thanks to a remarkable symmetry of an elliptic hypergeometric beta integral, proved very recently by van de Bult.

  2. 2D growth processes: SLE and Loewner chains

    Bauer, Michel [Service de Physique Theorique de Saclay, CE-Saclay, 91191 Gif-sur-Yvette (France) and Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris (France)]. E-mail: michel.bauer@cea.fr; Bernard, Denis [Service de Physique Theorique de Saclay, CE-Saclay, 91191 Gif-sur-Yvette (France) and Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris (France)]. E-mail: denis.bernard@cea.fr

    2006-10-15

    This review provides an introduction to two dimensional growth processes. Although it covers a variety of processes such as diffusion limited aggregation, it is mostly devoted to a detailed presentation of stochastic Schramm-Loewner evolutions (SLE) which are Markov processes describing interfaces in 2D critical systems. It starts with an informal discussion, using numerical simulations, of various examples of 2D growth processes and their connections with statistical mechanics. SLE is then introduced and Schramm's argument mapping conformally invariant interfaces to SLE is explained. A substantial part of the review is devoted to reveal the deep connections between statistical mechanics and processes, and more specifically to the present context, between 2D critical systems and SLE. Some of the remarkable properties of SLE are explained, together with the tools for computing with it. This review has been written with the aim of filling the gap between the mathematical and the physical literature on the subject.

  3. 2D bifurcations and Newtonian properties of memristive Chua's circuits

    Marszalek, W.; Podhaisky, H.

    2016-01-01

    Two interesting properties of Chua's circuits are presented. First, two-parameter bifurcation diagrams of Chua's oscillatory circuits with memristors are presented. To obtain various 2D bifurcation images a substantial numerical effort, possibly with parallel computations, is needed. The numerical algorithm is described first and its numerical code for 2D bifurcation image creation is available for free downloading. Several color 2D images and the corresponding 1D greyscale bifurcation diagrams are included. Secondly, Chua's circuits are linked to Newton's law φ ''= F(t,φ,φ')/m with φ=\\text{flux} , constant m > 0, and the force term F(t,φ,φ') containing memory terms. Finally, the jounce scalar equations for Chua's circuits are also discussed.

  4. CH2D+, the Search for the Holy Grail

    Roueff, Evelyne; Gerin, Maryvonne; Lis, Dariusz C.; Wootten, Alwyn; Marcelino, Nuria; Cernicharo, Jose; Tercero, Belen

    2013-10-01

    CH2D+, the singly deuterated counterpart of CH3+, offers an alternative way to mediate formation of deuterated species at temperatures of several tens of Kelvin, as compared to the release of deuterated species from grains. We report a longstanding observational search for this molecular ion, whose rotational spectroscopy is not yet completely secure. We summarize the main spectroscopic properties of this molecule and discuss the chemical network leading to the formation of CH2D+, with explicit account of the ortho/para forms of H2, H3+, and CH3+. Astrochemical models support the presence of this molecular ion in moderately warm environments at a marginal level.

  5. CH2D+, the Search for the Holy Grail

    Roueff, E; Lis, D C; Wootten, A; Marcelino, N; cernicharo, J; Tercero, B

    2013-01-01

    CH2D+, the singly deuterated counterpart of CH3+, offers an alternative way to mediate formation of deuterated species at temperatures of several tens of K, as compared to the release of deuterated species from grains. We report a longstanding observational search for this molecular ion, whose rotational spectroscopy is not yet completely secure. We summarize the main spectroscopic properties of this molecule and discuss the chemical network leading to the formation of CH2D+, with explicit account of the ortho/para forms of H2, H3+ and CH3+. Astrochemical models support the presence of this molecular ion in moderately warm environments at a marginal level.

  6. Design of the LRP airfoil series using 2D CFD

    This paper describes the design and wind tunnel testing of a high-Reynolds number, high lift airfoil series designed for wind turbines. The airfoils were designed using direct gradient- based numerical multi-point optimization based on a Bezier parameterization of the shape, coupled to the 2D Navier-Stokes flow solver EllipSys2D. The resulting airfoils, the LRP2-30 and LRP2-36, achieve both higher operational lift coefficients and higher lift to drag ratios compared to the equivalent FFA-W3 airfoils

  7. Isotropic 2D quadrangle meshing with size and orientation control

    Pellenard, Bertrand

    2011-12-01

    We propose an approach for automatically generating isotropic 2D quadrangle meshes from arbitrary domains with a fine control over sizing and orientation of the elements. At the heart of our algorithm is an optimization procedure that, from a coarse initial tiling of the 2D domain, enforces each of the desirable mesh quality criteria (size, shape, orientation, degree, regularity) one at a time, in an order designed not to undo previous enhancements. Our experiments demonstrate how well our resulting quadrangle meshes conform to a wide range of input sizing and orientation fields.

  8. 2D-ACAR investigations of PPT aramid fibres

    2D-ACAR spectra of PPT (poly(p-phenylene terephthalamide)) fibres which contain structural elongated open spaces in the crystallographic unit cell show a p-Ps peak with an elliptical cross-section and side lobes. Peak broadening suggests dimensions of ∝14-17 by 7-9 A for the open spaces and indicates some penetration of Ps into the interlayer spacing. The side lobes can be related to projected reciprocal lattice points and indicate Ps delocalization. 2D-ACAR has also been used to study the evolution of water release from the open spaces. (orig.)

  9. EEG simulation by 2D interconnected chaotic oscillators

    Research highlights: → ANN of 2D interconnected chaotic oscillators is explored for EEG simulation. → An inverse problem solution (PRCGA) is proposed. → Good matching between the simulated and experimental EEG signals has been achieved. - Abstract: An artificial neuronal network composed by 2D interconnected chaotic oscillators is explored for brain waves (EEG) simulation. For the inverse problem solution a parallel real-coded genetic algorithm (PRCGA) is proposed. In order to conduct thorough comparison between the simulated and target signal characteristics, a spectrum analysis of the signals is undertaken. A good matching between the theoretical and experimental EEG signals has been achieved. Numerical results of calculations are presented and discussed.

  10. Design of the LRP airfoil series using 2D CFD

    Zahle, Frederik; Bak, Christian; Sørensen, Niels N.;

    2014-01-01

    This paper describes the design and wind tunnel testing of a high-Reynolds number, high lift airfoil series designed for wind turbines. The airfoils were designed using direct gradient- based numerical multi-point optimization based on a Bezier parameterization of the shape, coupled to the 2D...... Navier-Stokes flow solver EllipSys2D. The resulting airfoils, the LRP2-30 and LRP2-36, achieve both higher operational lift coefficients and higher lift to drag ratios compared to the equivalent FFA-W3 airfoils....

  11. Quantum process tomography by 2D fluorescence spectroscopy

    Pachón, Leonardo A. [Grupo de Física Atómica y Molecular, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Andrew H. [Department of Chemistry and Biochemistry, Oregon Center for Optics, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 (United States); Aspuru-Guzik, Alán [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-06-07

    Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

  12. Synthesis of 2D materials in arc plasmas

    In this article we review recent efforts focused on synthesis of two-dimensional (2D) materials in an arc-plasma based process with particular focus on graphene. We present state-of-the-art experimental data on various attempts to employ the arc plasma technique for the graphene synthesis and consider growth mechanisms including precipitation, surface-catalyzed processes and a substrate-independent approach. The potential of arc synthesis for the growth of other types of 2D materials and future prospects are discussed. (review article)

  13. Nomenclature for human CYP2D6 alleles.

    Daly, A K; Brockmöller, J; Broly, F; Eichelbaum, M; Evans, W E; Gonzalez, F J; Huang, J D; Idle, J R; Ingelman-Sundberg, M; Ishizaki, T; Jacqz-Aigrain, E; Meyer, U A; Nebert, D W; Steen, V M; Wolf, C R; Zanger, U M

    1996-06-01

    To standardize CYP2D6 allele nomenclature, and to conform with international human gene nomenclature guidelines, an alternative to the current arbitrary system is described. Based on recommendations for human genome nomenclature, we propose that alleles be designated by CYP2D6 followed by an asterisk and a combination of roman letters and arabic numerals distinct for each allele with the number specifying the key mutation and, where appropriate, a letter specifying additional mutations. Criteria for classification as a separate allele and protein nomenclature are also presented. PMID:8807658

  14. Quantum process tomography by 2D fluorescence spectroscopy

    Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed

  15. SKIMO: corto de animación 2D

    VALERO BALLESTER, AIDA AMPARO

    2015-01-01

    El siguiente Trabajo Final de Grado llamado “Skimo” consiste en un teaser de animación 2D enfocado a ser finalizado el próximo año durante la realización del Diploma en Animación de personajes 2D del Máster de animación. Realizado en solitario como reto personal durante el curso presente, siendo la primera vez que trabajaba la animación. Para este proyecto he realizado toda la preproducción (layout, animática, storyboard, diseño de personajes, fondos, etc), animación en pape...

  16. Self-dual strings and 2D SYM

    Hosomichi, Kazuo; Lee, Sungjay

    2015-01-01

    We study the system of M2-branes suspended between parallel M5-branes using ABJM model with a natural half-BPS boundary condition. For small separation between M5-branes, the worldvolume theory is shown to reduce to a 2D super Yang-Mills theory with some similarity to q-deformed Yang-Mills theory. The gauge coupling is related to the position of the branes in an interesting manner. The theory is considerably different from the 2D theory proposed for multiple "M-strings". We make a detailed comparison of elliptic genus of the two descriptions and find only a partial agreement.

  17. Self-dual Strings and 2D SYM

    Hosomichi, Kazuo

    2014-01-01

    We study the system of M2-branes suspended between parallel M5-branes using ABJM model with a natural half-BPS boundary condition. For small separation between M5-branes, the worldvolume theory is shown to reduce to a 2D N=(4,4) super Yang-Mills theory with some similarity to q-deformed Yang-Mills theory. The gauge coupling is related to the position of the branes in an interesting manner. The theory is considerably different from the 2D theory proposed for multiple "M-strings". We make a detailed comparison of elliptic genus of the two descriptions and find only a partial agreement.

  18. A novel improved method for analysis of 2D diffusion relaxation data—2D PARAFAC-Laplace decomposition

    Tønning, Erik; Polders, Daniel; Callaghan, Paul T.; Engelsen, Søren B.

    2007-09-01

    This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T2- D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T2- D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T2- D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D = 3 × 10 -12 m 2 s -1 and T2 = 180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D = 10 -9 m 2 s -1, T2 = 10 ms and D = 3 × 10 -13 m 2 s -1, T2 = 13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it

  19. Overlapping patterns of brain activation to food and cocaine cues in cocaine abusers: association to striatal D2/D3 receptors

    Tomasi, Dardo; Wang, Gene-Jack; Wang, Ruiliang; Caparelli, Elisabeth C.; Logan, Jean; Volkow, Nora D.

    2014-01-01

    Cocaine, through its activation of dopamine (DA) signaling, usurps pathways that process natural rewards. However, the extent to which there is overlap between the networks that process natural and drug rewards and whether DA signaling associated with cocaine abuse influences these networks have not been investigated in humans. We measured brain activation responses to food and cocaine cues with fMRI, and D2/D3 receptors in the striatum with [11C]raclopride and PET in 20 active cocaine abuser...

  20. CYP2D6基因与药物代谢%CYP2D6 gene and drug metabolism

    施安国

    2003-01-01

    细胞色素P-450(CYP)中的CYP2D6酶在抗抑郁药、安定药及某些抗心律失常药的代谢中起重要作用,CYP2D6基因位于22号常染色体上为隐性遗传,CYP2D6基因呈多态性约有70余种等位基因变异型,也存在特异人群差别,因而导致所编码的酶活性不同,这些数据有助于理解药物代谢的个体差异、有助于预测药物之间的相互作用.

  1. Influence of Isotope Effects on Product Polarizations of N(2D)+D2,N(2D)+H2 and N(2D)+HD Reactive Systems

    NIE Shan-shan; CHU Tian-shu

    2012-01-01

    To figure out the influence of isotope effect on product polarizations of the N(2D)+D2 reactive system and its isotope variants,quasi-classical trajectory(QCT) calculation was performed on Ho's potential energy surfacc(PES) of 2A" state.Product polarizations such as product distributions ofP(θr),P(φr) and P(θr,φr),as well as the generalized polarization-dependent differential cross sections(PDDCSs) were discussed and compared in detail among the four product channels of the title reactions.Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.

  2. Creation of a scalar potential in 2D dilaton gravity

    Behrndt, K.

    1994-01-01

    We investigate quantum corrections of the 2-d dilaton gravity near the singularity. Our motivation comes from a s-wave reduced cosmological solution which is classically singular in the scalar fields (dilaton and moduli). As result we find, that the singularity disappears and a dilaton/moduli potential is created.

  3. ELLIPT2D: A Flexible Finite Element Code Written Python

    The use of the Python scripting language for scientific applications and in particular to solve partial differential equations is explored. It is shown that Python's rich data structure and object-oriented features can be exploited to write programs that are not only significantly more concise than their counter parts written in Fortran, C or C++, but are also numerically efficient. To illustrate this, a two-dimensional finite element code (ELLIPT2D) has been written. ELLIPT2D provides a flexible and easy-to-use framework for solving a large class of second-order elliptic problems. The program allows for structured or unstructured meshes. All functions defining the elliptic operator are user supplied and so are the boundary conditions, which can be of Dirichlet, Neumann or Robbins type. ELLIPT2D makes extensive use of dictionaries (hash tables) as a way to represent sparse matrices.Other key features of the Python language that have been widely used include: operator over loading, error handling, array slicing, and the Tkinter module for building graphical use interfaces. As an example of the utility of ELLIPT2D, a nonlinear solution of the Grad-Shafranov equation is computed using a Newton iterative scheme. A second application focuses on a solution of the toroidal Laplace equation coupled to a magnetohydrodynamic stability code, a problem arising in the context of magnetic fusion research

  4. Wilson loop in 2d noncommutative gauge theories

    Valtancoli, Paolo

    2009-01-01

    We reconsider the perturbative expansion of the Wilson loop in 2d noncommutative gauge theories, using an improved integration method. For the class of maximally crossed diagrams in the $\\theta \\to \\infty$ limit we find an intriguing formula, easily generalizable to all orders in perturbation theory.

  5. 2D fluid simulations of interchange turbulence with ion dynamics

    Nielsen, Anders Henry; Madsen, Jens; Xu, G. S.;

    2013-01-01

    In this paper we present a first principle global two-dimensional fluid model. The HESEL (Hot Edge SOL Electrostatic) model is a 2D numerical fluid code, based on interchange dynamics and includes besides electron also the ion pressure dynamic. In the limit of cold ions the model almost reduces to...

  6. The 2dF Galaxy Redshift Survey: Preliminary Results

    Maddox, S.

    1997-01-01

    Spectroscopic observations for a new survey of 250 000 galaxy redshifts are underway, using the 2dF instrument at the AAT. The input galaxy catalogue and commissioning data are described. The first result from the preliminary data is a new estimate of the galaxy luminosity function at =0.1.

  7. H on He: sticking and 2d-superfluidity

    The sticking coefficient, which governs the sticking time τs, is discussed for high surface-coverage conditions. We point out that τs must remain large compared to a characteristic vortex diffusion time, if the system is to display 2d-superfluidity

  8. Lattice simulation of 2d Gross-Neveu-type models

    Full text: We discuss a Monte Carlo simulation of 2d Gross-Neveu-type models on the lattice. The four-Fermi interaction is written as a Gaussian integral with an auxiliary field and the fermion determinant is included by reweighting. We present results for bulk quantities and correlators and compare them to a simulation using a fermion-loop representation. (author)

  9. Interactive Exploratory Visualization of 2D Vector Fields

    Isenberg, Tobias; Everts, Maarten H.; Grubert, Jens; Carpendale, Sheelagh

    2008-01-01

    In this paper we present several techniques to interactively explore representations of 2D vector fields. Through a set of simple hand postures used on large, touch-sensitive displays, our approach allows individuals to custom-design glyphs (arrows, lines, etc.) that best reveal patterns of the unde

  10. The toroidal Hausdorff dimension of 2d Euclidean quantum gravity

    Ambjorn, Jan; Budd, Timothy George

    2013-01-01

    The lengths of shortest non-contractible loops are studied numerically in 2d Euclidean quantum gravity on a torus coupled to conformal field theories with central charge less than one. We find that the distribution of these geodesic lengths displays a scaling in agreement with a Hausdorff dimension...

  11. Resolution deconvolution method applied to 2D-ACAR measurements

    An inexpensive way to achieve high resolution 2D-ACAR measurements is to utilize resolution deconvolution techniques. We developed a resolution deconvolution method which avoids noise amplification and is applicable to the 3D reconstruction method using Fourier-Bessel transforms. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Validation of minor species of the MIPAS2D database

    Enzo Papandrea; Stefano Casadio; Enrico Arnone; Massimo Carlotti; Elisa Castelli; Marta De Laurentis; Bianca Maria Dinelli

    2014-01-01

    The MIPAS2D [Dinelli et al., 2010] database has been developed applying the tomographic analysis technique GMTR [Carlotti et al., 2001] to measurements acquired in the nominal observation mode of the complete MIPAS (Michelson Interferometer for Passive Atmosphere Sounding) [Fischer et al., 2008] mission. […

  13. Validation of minor species of the MIPAS2D database

    Enzo Papandrea

    2014-01-01

    Full Text Available The MIPAS2D [Dinelli et al., 2010] database has been developed applying the tomographic analysis technique GMTR [Carlotti et al., 2001] to measurements acquired in the nominal observation mode of the complete MIPAS (Michelson Interferometer for Passive Atmosphere Sounding [Fischer et al., 2008] mission. […

  14. High resolution 2D image upconversion of incoherent light

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    An optimized method for continuous wave 2-dimensional (2-D) upconversion of incoherent or thermal light is demonstrated and quantified. Using standard resolution targets a resolution of 200×1000 pixels is obtained. The suggested method is viewed in scope of modern CCD cameras operating in the near...

  15. On the phase diagram of 2d Lorentzian Quantum Gravity

    Ambjørn, Jan; Anagnostopoulos, K. N.; Loll, R.

    The phase diagram of 2d Lorentzian quantum gravity (LQG) coupled to conformal matter is studied. A phase transition is observed at c = c crit ( {1}/{2} < c crit < 4) which can be thought of as the analogue of the c = 1 barrier of Euclidean quantum gravity (EQG). The non-trivial properties of the quantum geometry are discussed.

  16. 2D kinematics of simulated disc merger remnants

    Jesseit, Roland; Naab, Thorsten; Peletier, Reynier F.; Burkert, Andreas

    2007-01-01

    We present a 2D kinematic analysis for a sample of simulated binary disc merger remnants with mass ratios 1:1 and 3:1. For the progenitor discs we used pure stellar models as well as models with 10 per cent of their mass in gas. A multitude of phenomena also observed in real galaxies are found in th

  17. On the sensitivity of the 2D electromagnetic invisibility cloak

    A computational study of the sensitivity of the two dimensional (2D) electromagnetic invisibility cloaks is performed with the finite element method. A circular metallic object is covered with the cloak and the effects of absorption, gain and disorder are examined. Also the effect of covering the cloak with a thin dielectric layer is studied.

  18. On the sensitivity of the 2D electromagnetic invisibility cloak

    Kaproulias, S. [Department of Physics, University of Patras, 26504 Patras (Greece); Sigalas, M.M., E-mail: sigalas@upatras.gr [Department of Materials Science, University of Patras, 26504 Patras (Greece)

    2012-10-15

    A computational study of the sensitivity of the two dimensional (2D) electromagnetic invisibility cloaks is performed with the finite element method. A circular metallic object is covered with the cloak and the effects of absorption, gain and disorder are examined. Also the effect of covering the cloak with a thin dielectric layer is studied.

  19. Strain Engineering of the Electronic Structure of 2D Materials

    Frank, Otakar; del Corro, Elena; Pea-Álvarez, M.; Morales-García, A.; Bouša, M.; Řáhová, Jaroslava; Kavan, Ladislav; Kalbáč, Martin

    Brno : Tanger Ltd., 2015. s. 33-33. ISBN 978-80-87294-59-8. [Nanocon 2015. International Conference /7./. 14.10.2015-16.10.2015, Ostrava] R&D Projects: GA ČR GA14-15357S Institutional support: RVO:61388955 Keywords : graphene * electronic structure * 2D materials Subject RIV: CF - Physical ; Theoretical Chemistry

  20. A VARIATIONAL MODEL FOR 2-D MICROPOLAR BLOOD FLOW

    He Ji-huan

    2003-01-01

    The micropolar fluid model is an essential generalization of the well-established Navier-Stokes model in the sense that it takes into account the microstructure of the fluid.This paper is devolted to establishing a variational principle for 2-D incompressible micropolar blood flow.

  1. Detection of N$_2$D$^+$ in a protoplanetary disk

    Huang, Jane

    2015-01-01

    Observations of deuterium fractionation in the solar system, and in interstellar and circumstellar material, are commonly used to constrain the formation environment of volatiles. Toward protoplanetary disks, this approach has been limited by the small number of detected deuterated molecules, i.e. DCO$^+$ and DCN. Based on ALMA Cycle 2 observations toward the disk around the T Tauri star AS 209, we report the first detection of N$_2$D$^+$ (J=3-2) in a protoplanetary disk. These data are used together with previous Submillimeter Array observations of N$_2$H$^+$ (J=3-2) to estimate a disk-averaged D/H ratio of 0.3--0.5, an order of magnitude higher than disk-averaged ratios previously derived for DCN/HCN and DCO$^+$/HCO$^+$ around other young stars. The high fractionation in N$_2$H$^+$ is consistent with model predictions. The presence of abundant N$_2$D$^+$ toward AS 209 also suggests that N$_2$D$^+$ and the N$_2$D$^+$/N$_2$H$^+$ ratio can be developed into effective probes of deuterium chemistry, kinematics, ...

  2. NKG2D ligands mediate immunosurveillance of senescent cells.

    Sagiv, Adi; Burton, Dominick G A; Moshayev, Zhana; Vadai, Ezra; Wensveen, Felix; Ben-Dor, Shifra; Golani, Ofra; Polic, Bojan; Krizhanovsky, Valery

    2016-02-01

    Cellular senescence is a stress response mechanism that limits tumorigenesis and tissue damage. Induction of cellular senescence commonly coincides with an immunogenic phenotype that promotes self-elimination by components of the immune system, thereby facilitating tumor suppression and limiting excess fibrosis during wound repair. The mechanisms by which senescent cells regulate their immune surveillance are not completely understood. Here we show that ligands of an activating Natural Killer (NK) cell receptor (NKG2D), MICA and ULBP2 are consistently up-regulated following induction of replicative senescence, oncogene-induced senescence and DNA damage - induced senescence. MICA and ULBP2 proteins are necessary for efficient NK-mediated cytotoxicity towards senescent fibroblasts. The mechanisms regulating the initial expression of NKG2D ligands in senescent cells are dependent on a DNA damage response, whilst continuous expression of these ligands is regulated by the ERK signaling pathway. In liver fibrosis, the accumulation of senescent activated stellate cells is increased in mice lacking NKG2D receptor leading to increased fibrosis. Overall, our results provide new insights into the mechanisms regulating the expression of immune ligands in senescent cells and reveal the importance of NKG2D receptor-ligand interaction in protecting against liver fibrosis. PMID:26878797

  3. 2-D Imaging of Electron Temperature in Tokamak Plasmas

    T. Munsat; E. Mazzucato; H. Park; C.W. Domier; M. Johnson; N.C. Luhmann Jr.; J. Wang; Z. Xia; I.G.J. Classen; A.J.H. Donne; M.J. van de Pol

    2004-07-08

    By taking advantage of recent developments in millimeter wave imaging technology, an Electron Cyclotron Emission Imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a 2-D map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the MHD activity associated with a sawtooth crash, is presented.

  4. 2-D Imaging of Electron Temperature in Tokamak Plasmas

    By taking advantage of recent developments in millimeter wave imaging technology, an Electron Cyclotron Emission Imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a 2-D map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the MHD activity associated with a sawtooth crash, is presented

  5. 2D molybdenum disulphide (2D-MoS2) modified electrodes explored towards the oxygen reduction reaction

    Rowley-Neale, Samuel J.; Fearn, Jamie M.; Brownson, Dale A. C.; Smith, Graham C.; Ji, Xiaobo; Banks, Craig E.

    2016-08-01

    Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm-2 modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.Two-dimensional molybdenum disulphide nanosheets

  6. Explaining MRI examinations DVD

    When conducting MRI examinations, there are various things to be careful of. There is often stress related to the MRI examinations, so in order to perform an examination safely and smoothly, sufficient explanation must be given. An explanation of what to do and what not to do during an examination should be outlined in a brochure given to patients before the examination. There may be many patients who have misgivings about their MRI examinations, so to reduce their anxiousness and deepen their understanding of MRI examinations and to improve the safety and effiency of MRI examinations,; we created a DVD about MRI examinations. We gathered MRI-related safety information and instructions, and assessed the effect that the information might have on patients. We started a workgroup for a project to plan and record a video according to the Storyboard. When editing, we reviewed the length of each segment, the amount of information on screen, and the overall length of the DVD. We discussed the issue within the workgroup and had hospital approval. It was possible for us to complete it without depending on the supplier and the cost was kept to a minimum. Finally, we decided on a viewing location. We asked a hospital volunteers to see a complete DVD and we evaluated their responses by questionnaires. As the result, their understanding and anxieties related to MRI examinations were alleviated, as expected. Their anxiety seemed to be eased. Patients also seemed to have a deeper understanding of MRI examinations having seen an examination being conducted. (author)

  7. Development and application of methods to quantify spatial and temporal hyperpolarized 3He MRI ventilation dynamics: preliminary results in chronic obstructive pulmonary disease

    Kirby, Miranda; Wheatley, Andrew; McCormack, David G.; Parraga, Grace

    2010-03-01

    Hyperpolarized helium-3 (3He) magnetic resonance imaging (MRI) has emerged as a non-invasive research method for quantifying lung structural and functional changes, enabling direct visualization in vivo at high spatial and temporal resolution. Here we described the development of methods for quantifying ventilation dynamics in response to salbutamol in Chronic Obstructive Pulmonary Disease (COPD). Whole body 3.0 Tesla Excite 12.0 MRI system was used to obtain multi-slice coronal images acquired immediately after subjects inhaled hyperpolarized 3He gas. Ventilated volume (VV), ventilation defect volume (VDV) and thoracic cavity volume (TCV) were recorded following segmentation of 3He and 1H images respectively, and used to calculate percent ventilated volume (PVV) and ventilation defect percent (VDP). Manual segmentation and Otsu thresholding were significantly correlated for VV (r=.82, p=.001), VDV (r=.87 p=.0002), PVV (r=.85, p=.0005), and VDP (r=.85, p=.0005). The level of agreement between these segmentation methods was also evaluated using Bland-Altman analysis and this showed that manual segmentation was consistently higher for VV (Mean=.22 L, SD=.05) and consistently lower for VDV (Mean=-.13, SD=.05) measurements than Otsu thresholding. To automate the quantification of newly ventilated pixels (NVp) post-bronchodilator, we used translation, rotation, and scaling transformations to register pre-and post-salbutamol images. There was a significant correlation between NVp and VDV (r=-.94 p=.005) and between percent newly ventilated pixels (PNVp) and VDP (r=- .89, p=.02), but not for VV or PVV. Evaluation of 3He MRI ventilation dynamics using Otsu thresholding and landmark-based image registration provides a way to regionally quantify functional changes in COPD subjects after treatment with beta-agonist bronchodilators, a common COPD and asthma therapy.

  8. MRI in perianal fistulae

    MRI has become the method of choice for evaluating perianal fistulae due to its ability to display the anatomy of the sphincter muscles orthogonally, with good contrast resolution. In this article we give an outline of the classification of perianal fistulae and present a pictorial assay of sphincter anatomy and the MRI findings in perianal fistulae. This study is based on a retrospective analysis of 43 patients with a clinical diagnosis of perianal fistula. MRI revealed a total of 44 fistulae in 35 patients; eight patients had only perianal sinuses

  9. MRI of brachial plexopathies

    Sureka, J. [Department of Radiology, Christian Medical College, Vellore (India)], E-mail: drjyoticmch@rediffmail.com; Cherian, R.A.; Alexander, M.; Thomas, B.P. [Department of Radiology, Christian Medical College, Vellore (India)

    2009-02-15

    Magnetic resonance imaging (MRI) has become the primary imaging technique in the evaluation of brachial plexus pathology, and plays an important role in the identification, localization, and characterization of the cause. Improvements in MRI technique have helped in detecting changes in the signal intensity of nerves, subtle enhancement, and in detecting perineural pathology, thereby refining the differential diagnosis. The present review of the visualization of brachial plexus abnormalities using MRI is based on a review of 26 cases. The causes include trauma and a spectrum of non-traumatic causes, such as acute idiopathic/viral plexitis, metastases, immune-mediated plexitis, and mass lesions compressing the brachial plexus.

  10. 2d-LCA - an alternative to x-wires

    Puczylowski, Jaroslaw; Hölling, Michael; Peinke, Joachim

    2014-11-01

    The 2d-Laser Cantilever Anemometer (2d-LCA) is an innovative sensor for two-dimensional velocity measurements in fluids. It uses a micostructured cantilever made of silicon and SU-8 as a sensing element and is capable of performing mesurements with extremly high temporal resolutions up to 150 kHz. The size of the cantilever defines its spatial resolution, which is in the order of 150 μm only. Another big feature is a large angular range of 180° in total. The 2d-LCA has been developed as an alternative measurement method to x-wires with the motivation to create a sensor that can operate in areas where the use of hot-wire anemometry is difficult. These areas include measurements in liquids and in near-wall or particle-laden flows. Unlike hot-wires, the resolution power of the 2d-LCA does not decrease with increasing flow velocity, making it particularly suitable for measurements in high speed flows. Comparative measurements with the 2d-LCA and hot-wires have been carried out in order to assess the performance of the new anemometer. The data of both measurement techniques were analyzed using the same stochastic methods including a spectral analysis as well as an inspection of increment statistics and structure functions. Furthermore, key parameters, such as mean values of both velocity components, angles of attack and the characteristic length scales were determined from both data sets. The analysis reveals a great agreement between both anemometers and thus confirms the new approach.

  11. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  12. Brain MRI in Parkinson's disease

    Meijer, F.J.A.; Goraj, B.M.

    2014-01-01

    In this review article, conventional brain MRI and advanced MRI techniques in Parkinson`s disease (PD) are discussed, with emphasis on clinical relevance. Conventional brain MRI sequences generally demonstrate limited abnormalities specific for PD and in clinical practice brain MRI is mainly used to

  13. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  14. MRI Volume Fusion Based on 3D Shearlet Decompositions.

    Duan, Chang; Wang, Shuai; Wang, Xue Gang; Huang, Qi Hong

    2014-01-01

    Nowadays many MRI scans can give 3D volume data with different contrasts, but the observers may want to view various contrasts in the same 3D volume. The conventional 2D medical fusion methods can only fuse the 3D volume data layer by layer, which may lead to the loss of interframe correlative information. In this paper, a novel 3D medical volume fusion method based on 3D band limited shearlet transform (3D BLST) is proposed. And this method is evaluated upon MRI T2* and quantitative susceptibility mapping data of 4 human brains. Both the perspective impression and the quality indices indicate that the proposed method has a better performance than conventional 2D wavelet, DT CWT, and 3D wavelet, DT CWT based fusion methods. PMID:24817880

  15. Dust dynamics in 2D gravito-turbulent disks

    Shi, Ji-Ming; Stone, James M; Chiang, Eugene

    2016-01-01

    The dynamics of solid bodies in protoplanetary disks are subject to the properties of any underlying gas turbulence. Turbulence driven by disk self-gravity shows features distinct from those driven by the magnetorotational instability (MRI). We study the dynamics of solids in gravito-turbulent disks with two-dimensional (in the disk plane), hybrid (particle and gas) simulations. Gravito-turbulent disks can exhibit stronger gravitational stirring than MRI-active disks, resulting in greater radial diffusion and larger eccentricities and relative speeds for large particles (those with dimensionless stopping times $t_{stop} \\Omega > 1$, where $\\Omega$ is the orbital frequency). The agglomeration of large particles into planetesimals by pairwise collisions is therefore disfavored in gravito-turbulent disks. However, the relative speeds of intermediate-size particles $t_{stop} \\Omega \\sim 1$ are significantly reduced as such particles are collected by gas drag and gas gravity into coherent filament-like structures ...

  16. Magnetic susceptibility measurement using 2D magnetic resonance imaging

    Marcon, P.; Bartušek, Karel; Burdkova, M.; Dokoupil, Zdeněk

    2011-01-01

    Roč. 22, č. 10 (2011), 105702:1-8. ISSN 0957-0233 R&D Projects: GA ČR GAP102/11/0318; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : magnetic flux density * magnetic susceptibility * MRI * MR signal * reaction field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.494, year: 2011

  17. 2D-2D tunneling field-effect transistors using WSe2/SnSe2 heterostructures

    Roy, Tania; Tosun, Mahmut; Hettick, Mark; Ahn, Geun Ho; Hu, Chenming; Javey, Ali

    2016-02-01

    Two-dimensional materials present a versatile platform for developing steep transistors due to their uniform thickness and sharp band edges. We demonstrate 2D-2D tunneling in a WSe2/SnSe2 van der Waals vertical heterojunction device, where WSe2 is used as the gate controlled p-layer and SnSe2 is the degenerately n-type layer. The van der Waals gap facilitates the regulation of band alignment at the heterojunction, without the necessity of a tunneling barrier. ZrO2 is used as the gate dielectric, allowing the scaling of gate oxide to improve device subthreshold swing. Efficient gate control and clean interfaces yield a subthreshold swing of ˜100 mV/dec for >2 decades of drain current at room temperature, hitherto unobserved in 2D-2D tunneling devices. The subthreshold swing is independent of temperature, which is a clear signature of band-to-band tunneling at the heterojunction. A maximum switching ratio ION/IOFF of 107 is obtained. Negative differential resistance in the forward bias characteristics is observed at 77 K. This work bodes well for the possibilities of two-dimensional materials for the realization of energy-efficient future-generation electronics.

  18. MRI of the Chest

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... in diagnosing a broad range of conditions, including cancer, heart and vascular disease, heart valve abnormalities, bone ...

  19. MRI of the shoulder

    Magnetic resonance imaging has become available at a time in which shoulder pathology is more frequently seen. It is a noninvasive procedure that does not use ionizing radiation. It provides detailed visualization of soft-tissue structures that is not possible with other imaging modalities. Though not as widely available as conventional radiographs or computed tomography scanning, the number of MRI units worldwide is increasing steadily. The main features of the present book are as follows: The physical basis of Magnetic Resonance Imaging (MRI), normal shoulder anatomy and MRI, diagnosis of shoulder disorders, MRI of patients with shoulder pain or instability, case studies as well as treatment of shoulder disorders. (orig./MG) With 145 figs

  20. Combined PET/MRI

    Bailey, D. L.; Pichler, B. J.; Gückel, B.;

    2015-01-01

    This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from...... February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology......, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both...

  1. MRI of myelitis

    Hodel, J.; Outteryck, O; Jissendi, P; Zins, M.; Leclerc, X; Pruvo, J P

    2012-01-01

    The diagnosis of myelitis relies on MRI. The purpose of this review is to describe the imaging findings in patients with myelitis through clinical cases. MR findings in Multiple Sclerosis, Neuromyelitis Optica and others Transverse Myelitis are highlighted.

  2. MRI of intracranial calcifications

    Kang, Jin Wha; Chang, Kee Hyun; Park, Jung Mi; Han, Moon Hee; Han, Man Chung; Kim, Chu Wan [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1988-12-15

    Recently computed tomography(CT) has been rapidly replaced by magnetic resonance imaging (MRI) in diagnosis of majority of intracranial diseases. But MRI still has some limitation, one of which is its inferiority in detecting calcification. MRI of intracranial calcification has been known to be variable in signal intensity. We retrospectively analyzed the MRI of 26 patients with intracranial calcified lesions in order to evaluate the MR intensity of calcification and to assess the capability of MRI in detecting calcification in various intracranial lesions. All the MRI were obtained using routine T1-and T2-weighted spin eco pulse sequences on 2.0T superconducting system. The 26 patients consisted of 13 brain tumors (4 oligodendrogliomas, 2 craniopharyngiomas, 2 astrocytomas, 1 gem cell tumor, 1 medulloblastoma, 1 ependympma, and pathologically unconfirmed 2 cases), 11 infectious diseases (1 paragonimiasis, 1 sparganosis, 2 cysticercosis, 3 tuberculosis, and 4 unknown cases), and 2 undetermined pathologies. Eighty-two percent (9/11) of infections disease, and 50% (1/2) of undetermined group showed signal diminution or signal void on both T1-and T2-weighted image (T1W1, T2W1). Twenty-four percent (3/13) of brain tumors showed signal diminution on both T1W1 and T2W1. In 46% (6/13) and 61% (8/13) of brain tumors the signal intensities were isointense on T1W1 and T1W1, respectively. Unexpectedly, 3 oligodendrogliomas showed high signal intensity on T1W1, two of which showed com plexed signal intensity mixed with high, iso, and low signal intensities on T2W1. In remained cases (18% (2/11) of infectious diseases and 50% (1/2) of undetermined group) the signal intensities were mixed. With simultaneous review of CT and MRI in each case, the calcification (at least one in cases showing multiple ones) was identifiable on MRI in 62% (8/13) of rumors, 82% (9/11) of infectious diseases, and 100% (2/2) in undetermined group. In 36% (4/11) of infectious diseases, fewer number of

  3. 2-D linear motion system. Innovative technology summary report

    The US Department of Energy's (DOE's) nuclear facility decontamination and decommissioning (D and D) program requires buildings to be decontaminated, decommissioned, and surveyed for radiological contamination in an expeditious and cost-effective manner. Simultaneously, the health and safety of personnel involved in the D and D activities is of primary concern. D and D workers must perform duties high off the ground, requiring the use of manlifts or scaffolding, often, in radiologically or chemically contaminated areas or in areas with limited access. Survey and decontamination instruments that are used are sometimes heavy or awkward to use, particularly when the worker is operating from a manlift or scaffolding. Finding alternative methods of performing such work on manlifts or scaffolding is important. The 2-D Linear Motion System (2-D LMS), also known as the Wall Walker trademark, is designed to remotely position tools and instruments on walls for use in such activities as radiation surveys, decontamination, and painting. Traditional (baseline) methods for operating equipment for these tasks require workers to perform duties on elevated platforms, sometimes several meters above the ground surface and near potential sources of contamination. The Wall Walker 2-D LMS significantly improves health and safety conditions by facilitating remote operation of equipment. The Wall Walker 2-D LMS performed well in a demonstration of its precision, accuracy, maneuverability, payload capacity, and ease of use. Thus, this innovative technology is demonstrated to be a viable alternative to standard methods of performing work on large, high walls, especially those that have potential contamination concerns. The Wall Walker was used to perform a final release radiological survey on over 167 m2 of walls. In this application, surveying using a traditional (baseline) method that employs an aerial lift for manual access was 64% of the total cost of the improved technology. However

  4. MRI of the penis

    Kirkham, A

    2012-01-01

    MRI of the penis is an expensive test that is not always superior to clinical examination or ultrasound. However, it shows many of the important structures, and in particular the combination of tumescence from intracavernosal alprostadil, and high-resolution T2 sequences show the glans, corpora and the tunica albuginea well. In this paper we summarise the radiological anatomy and discuss the indications for MRI. For penile cancer, it may be useful in cases where the local stage is not apparen...

  5. MRI assessment program

    The MRI Assessment Program involves installation and operation of five MRI units in Australian public hospitals and the evaluation at each unit of the cost and efficacy of the technology over a period of two years. This first report in a series presents preliminary usage and cost data for the year to 30 June 1987 as well as describing the background and the data set. 6 figs., tabs

  6. MRI in osteochondrosis dissecans

    The osseous manifestations of osteochondrosis dissecans are well demonstrated by conventional and computerised tomography. Beyond that, magnetic resonance imaging (MRI) is effective in evaluating the vitality and loosening of an osseous dissecate. Subchondral cavities and cartilaginous defects are detected with high acccuracy. Further, MRI seems to be a useful method in childhood to differentiate a variant irregularity of the osseous articular surface from definite osteochondrosis dissecans. (orig.)

  7. MRI of plantar fasciitis

    Roger, B.; Grenier, P. [Service de Radiologie Polyvalente Diagnostique et Interventionelle, Hopital de la Pitie, 83, boulevard de l`Hopital, F-75651 Paris Cedex 13 (France)

    1997-12-01

    At present, MRI is the only imaging method that can precisely visualize lesions of the superficial plantar aponeurosis, whether they be musculoaponeurositides, enthesopathies or tears, and whether they be acute or chronic, with or without complications. By its direct visualization of the lesion, MRI enables an accurate assessment of the injury to be made and thereby better orients the therapeutic strategy. (orig.) With 11 figs., 15 refs.

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

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

    1995-12-31

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

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

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

  10. Posttraumatic pseudolipoma: MRI appearances

    The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancement. (orig.)

  11. MRI of fish

    Recently, rats and mice are popular and useful as an experimental model for MRI. However, MRI for fishes has been unknown. This study aimed to investigate the usefulness of living fishes as a new experimental model for MRI. MR images were collected with a spin-echo pulse sequence (SE) or echo-planar imaging pulse sequence (EPI) using 2T MR imaging system for animal. Carp, which was able to be alive for a long time in the air, was examined. Enhancement study was examined by use of Gd-DOTMA (gadolinium hydrogen alpha, alpha', alpha'', alpha'''-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). On both SE and EPI images, the internal components of the head and chest in carp were clearly recognized. On the T1-weighted image acquisition time of MRI with sufficient resolution was short (in about one minute) in comparison with that of rat. The head in carp was well enhanced by administration of Gd-DOTMA on the T1-weighted image. In addition, the time course of contrast enhancement effect of images was observed after administration of Gd-DOTMA. The authors concluded that fishes, such as a carp, can be readily imaged on MRI, and could be potential in the future investigation of contrast enhancement effect and relaxation effect as a living body phantom for MRI. (author)

  12. Posttraumatic pseudolipoma: MRI appearances

    Theumann, N.; Abdelmoumene, A.; Wintermark, M.; Schnyder, P.; Gailloud, M.C.; Resnick, D. [CHUV, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland)

    2005-09-01

    The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancement. (orig.)

  13. Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes

    The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path. For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm for a translation of 39.9 mm. We have demonstrated how interleaved acquired, orthogonal cine-MRI planes can be used for online tracking of soft-tissue target volumes. (paper)

  14. Three-dimensional versus two-dimensional sonography of the temporomandibular joint in comparison to MRI

    Aim: To compare clinical feasibility of static two-dimensional (2D) to three-dimensional (3D) sonography of the temporomandibular joint (TMJ) in assessment of disk dislocation and joint degeneration compared to magnetic resonance imaging (MRI). Method: Thirty-three patients, 66 TMJ were prospectively sonographed 2D and 3D (8-12.5 MHz step motor scan), in occlusion and maximum opening with a probe position parallel inferior to the zygomatic arch. Axial 2D images were judged independent from the 3D scans; 3D volumes were cut axial, sagittal, frontal and rotated in real-time. Disk position and joint degeneration were assessed and compared to a subsequent MRI examination. Results: The specific appearance of the disk was hypoechogenic overlying a hyperechogenic condyle in axial (2D) or sagittal and frontal (3D) viewing. Specificity of 2D sonography for disk dislocation was 63%, sensitivity 58%, accuracy 64%, positive predictive value 46%, negative predictive value 73%; for joint degeneration synonymously 59/68/61/38/83%. 3D sonography for disk displacement reached synonymously 68/60/69/51/76%, for joint degeneration 75/65/73/48/86%. 2D sonographic diagnoses of disk dislocation in the closed mouth position and of joint degeneration showed significantly different results from the expected values (MRI) in χ 2 testing; 3D diagnoses of disk dislocation in closed mouth position, of joint degeneration, 2D and 3D diagnoses in open mouth position were nonsignificant. Conclusions: Acceptable was the overall negative predictive value, as specificity and accuracy for joint degeneration in 3D. 3D appears superior diagnosing disk dislocation in closed mouth position as for overall joint degeneration. Sensitivity, accuracy and positive predictive value will have to ameliorate with future equipment of higher resolution in real-time 2D and 3D, if sonographic screening shall be clinically applied prior to MRI

  15. Three-dimensional versus two-dimensional sonography of the temporomandibular joint in comparison to MRI

    Landes, Constantin A. [Oral, Maxillofacial and Plastic Facial Surgery, Frankfurt University Medical Centre, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)]. E-mail: c.landes@lycos.com; Goral, Wojciech A. [Oral, Maxillofacial and Plastic Facial Surgery, Frankfurt University Medical Centre, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)]. E-mail: w.goral@gmx.de; Sader, Robert [Oral, Maxillofacial and Plastic Facial Surgery, Frankfurt University Medical Centre, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)]. E-mail: r.sader@em.uni-frankfurt.de; Mack, Martin G. [Department of Diagnostic and Interventional Radiology, Frankfurt University Medical Centre, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)]. E-mail: martinmack@arcor.de

    2007-02-15

    Aim: To compare clinical feasibility of static two-dimensional (2D) to three-dimensional (3D) sonography of the temporomandibular joint (TMJ) in assessment of disk dislocation and joint degeneration compared to magnetic resonance imaging (MRI). Method: Thirty-three patients, 66 TMJ were prospectively sonographed 2D and 3D (8-12.5 MHz step motor scan), in occlusion and maximum opening with a probe position parallel inferior to the zygomatic arch. Axial 2D images were judged independent from the 3D scans; 3D volumes were cut axial, sagittal, frontal and rotated in real-time. Disk position and joint degeneration were assessed and compared to a subsequent MRI examination. Results: The specific appearance of the disk was hypoechogenic overlying a hyperechogenic condyle in axial (2D) or sagittal and frontal (3D) viewing. Specificity of 2D sonography for disk dislocation was 63%, sensitivity 58%, accuracy 64%, positive predictive value 46%, negative predictive value 73%; for joint degeneration synonymously 59/68/61/38/83%. 3D sonography for disk displacement reached synonymously 68/60/69/51/76%, for joint degeneration 75/65/73/48/86%. 2D sonographic diagnoses of disk dislocation in the closed mouth position and of joint degeneration showed significantly different results from the expected values (MRI) in {chi} {sup 2} testing; 3D diagnoses of disk dislocation in closed mouth position, of joint degeneration, 2D and 3D diagnoses in open mouth position were nonsignificant. Conclusions: Acceptable was the overall negative predictive value, as specificity and accuracy for joint degeneration in 3D. 3D appears superior diagnosing disk dislocation in closed mouth position as for overall joint degeneration. Sensitivity, accuracy and positive predictive value will have to ameliorate with future equipment of higher resolution in real-time 2D and 3D, if sonographic screening shall be clinically applied prior to MRI.

  16. A brief review of the 2d/4d correspondences

    Tachikawa, Yuji

    2016-01-01

    An elementary introduction to the 2d/4d correspondences is given. After quickly reviewing the 2d q-deformed Yang-Mills theory and the Liouville theory, we will introduce 4d theories obtained by coupling trifundamentals to SU(2) gauge fields. We will then see concretely that the supersymmetric partition function of these theories on S^3 x S^1 and on S^4 is given respectively by the q-deformed Yang-Mills theory and the Liouville theory. After giving a short discussion on how this correspondence may be understood from the viewpoint of the 6d N=(2,0) theory, we conclude the review by enumerating future directions. Most of the technical points will be referred to more detailed review articles.

  17. Security Issues for 2D Barcodes Ticketing Systems

    Cristian Toma

    2011-03-01

    Full Text Available The paper presents a solution for endcoding/decoding access to the subway public transportation systems. First part of the paper is dedicated through section one and two to the most used 2D barcodes used in the market – QR and DataMatrix. The sample for DataMatrix is author propietary and the QR sample is from the QR standard [2]. The section three presents MMS and Digital Rights Management topics used for issuing the 2D barcodes tickets. The second part of the paper, starting with section four shows the architecture of Subway Ticketing Systems and the proposed procedure for the ticket issuing. The conclusions identify trends of the security topics in the public transportation systems.

  18. Characterization of steady solutions to the 2D Euler equation

    Izosimov, Anton

    2015-01-01

    Steady fluid flows have very special topology. In this paper we describe necessary and sufficient conditions on the vorticity function of a 2D ideal flow on a surface with or without boundary, for which there exists a steady flow among isovorticed fields. For this we introduce the notion of an antiderivative (or circulation function) on a measured graph, the Reeb graph associated to the vorticity function on the surface, while the criterion is related to the total negativity of this antiderivative. It turns out that given topology of the vorticity function, the set of coadjoint orbits of the symplectomorphism group admitting steady flows with this topology forms a convex polytope. As a byproduct of the proposed construction, we also describe a complete list of Casimirs for the 2D Euler hydrodynamics: we define generalized enstrophies which, along with circulations, form a complete set of invariants for coadjoint orbits of area-preserving diffeomorphisms on a surface.

  19. 2D/3D Program work summary report

    The 2D/3D Program was carried out by Germany, Japan and the United States to investigate the thermal-hydraulics of a PWR large-break LOCA. A contributory approach was utilized in which each country contributed significant effort to the program and all three countries shared the research results. Germany constructed and operated the Upper Plenum Test Facility (UPTF), and Japan constructed and operated the Cylindrical Core Test Facility (CCTF) and the Slab Core Test Facility (SCTF). The US contribution consisted of provision of advanced instrumentation to each of the three test facilities, and assessment of the TRAC computer code against the test results. Evaluations of the test results were carried out in all three countries. This report summarizes the 2D/3D Program in terms of the contributing efforts of the participants, and was prepared in a coordination among three countries. US and Germany have published the report as NUREG/IA-0126 and GRS-100, respectively. (author)

  20. Calculation of wakefields in 2D rectangular structures

    We consider the calculation of electromagnetic fields generated by an electron bunch passing through a vacuum chamber structure that, in general, consists of an entry pipe, followed by some kind of transition or cavity, and ending in an exit pipe. We limit our study to structures having rectangular cross-section, where the height can vary as function of longitudinal coordinate but the width and side walls remain fixed. For such structures, we derive a Fourier representation of the wake potentials through one-dimensional functions. A new numerical approach for calculating the wakes in such structures is proposed and implemented in the computer code ECHO(2D). The computation resource requirements for this approach are moderate and comparable to those for finding the wakes in 2D rotationally symmetric structures. Numerical examples obtained with the new numerical code are presented.

  1. A SUBARRAY-SYNTHESIS BASED 2D DOA ESTIMATION METHOD

    Xu Wenlong; Jiang Wei; Li Zengfu; Shang Yong; Xiang Haige

    2006-01-01

    In some satellite communications, we need to perform Direction Of Arrival (DOA) angle estimation under the restriction that the number of receivers is less than that of the array elements in an array antenna.To solve the conundrum, a method named subarray-synthesis-based Two-Dimensional DOA (2D DOA) angle estimation is proposed. In the method, firstly, the array antenna is divided into a series of subarray antennas based on the total number of receivers; secondly, the subarray antennas' output covariance matrices are estimated; thirdly, an equivalent covariance matrix is synthesized based on the subarray output covariance matrices; then 2D DOA estimation is performed. Monte Carlo simulations showed that the estimation method is effective.

  2. Estimating 2-D Vector Velocities Using Multidimensional Spectrum Analysis

    Oddershede, Niels; Løvstakken, Lasse; Torp, Hans;

    2008-01-01

    . Later, it was shown that this approach could also be used for finding the lateral velocity component by also including a lateral sampling. A single velocity component would then be concentrated along a plane in the 3-D Fourier space, tilted according to the 2 velocity components. This paper presents 2...... minimum variance approach. Based on this plane, the axial and lateral velocity components are estimated. Several phantom measurements, for flow-to-depth angles of 60, 75, and 90 degrees, were performed. Multiple parallel lines were beamformed simultaneously, and 2 different receive apodization schemes......Wilson (1991) presented an ultrasonic wide-band estimator for axial blood flow velocity estimation through the use of the 2-D Fourier transform. It was shown how a single velocity component was concentrated along a line in the 2-D Fourier space, where the slope was given by the axial velocity...

  3. Two-Dimensional (2D) Polygonal Electromagnetic Cloaks

    Transformation optics offers remarkable control over electromagnetic fields and opens an exciting gateway to design 'invisible cloak devices' recently. We present an important class of two-dimensional (2D) cloaks with polygon geometries. Explicit expressions of transformed medium parameters are derived with their unique properties investigated. It is found that the elements of diagonalized permittivity tensors are always positive within an irregular polygon cloak besides one element diverges to plus infinity and the other two become zero at the inner boundary. At most positions, the principle axes of permittivity tensors do not align with position vectors. An irregular polygon cloak is designed and its invisibility to external electromagnetic waves is numerically verified. Since polygon cloaks can be tailored to resemble any objects, the transformation is finally generalized to the realization of 2D cloaks with arbitrary geometries. (fundamental areas of phenomenology (including applications))

  4. Interpretation of Magnetic Phase Anomalies over 2D Tabular Bodies

    Subrahmanyam, M.

    2016-05-01

    In this study, phase angle (inverse tangent of the ratio of the horizontal to vertical gradients of magnetic anomalies) profile over two-dimensional tabular bodies has been subjected to detailed analysis for determining the source parameters. Distances between certain characteristic positions on this phase curve are related to the parameters of two-dimensional tabular magnetic sources. In this paper, I have derived the mathematical expressions for these relations. It has been demonstrated here that for locating the origin of the 2D tabular source, knowledge on the type of the model (contact, sheet, dyke, and fault) is not necessary. A procedure is evolved to determine the location, depth, width and magnetization angle of the 2D sources from the mathematical expressions. The method is tested on real field data. The effect of the overlapping bodies is also discussed with two synthetic examples. The interpretation technique is developed for contact, sheet, dike and inclined fault bodies.

  5. Planar maps, circle patterns and 2d gravity

    David, Francois

    2013-01-01

    Via circle pattern techniques, random planar triangulations (with angle variables) are mapped onto Delaunay triangulations in the complex plane. The uniform measure on triangulations is mapped onto a conformally invariant spatial point process. We show that this measure can be expressed as: (1) a sum over 3-spanning-trees partitions of the edges of the Delaunay triangulations; (2) the volume form of a K\\"ahler metric over the space of Delaunay triangulations, whose prepotential has a simple formulation in term of ideal tessellations of the 3d hyperbolic space; (3) a discretized version (involving finite difference complex derivative operators) of Polyakov's conformal Fadeev-Popov determinant in 2d gravity; (4) a combination of Chern classes, thus also establishing a link with topological 2d gravity.

  6. Bulk correlation functions in 2D quantum gravity

    Kostov, I K

    2005-01-01

    We compute bulk 3- and 4-point tachyon correlators in the 2d Liouville gravity with non-rational matter central charge c<1, following and comparing two approaches. The continuous CFT approach exploits the action on the tachyons of the ground ring generators deformed by Liouville and matter ``screening charges''. A by-product general formula for the matter 3-point OPE structure constants is derived. We also consider a ``diagonal'' CFT of 2D quantum gravity, in which the degenerate fields are restricted to the diagonal of the semi-infinite Kac table. The discrete formulation of the theory is a generalization of the ADE string theories, in which the target space is the semi-infinite chain of points.

  7. Wave propagation in pantographic 2D lattices with internal discontinuities

    Madeo, A; Neff, P

    2014-01-01

    In the present paper we consider a 2D pantographic structure composed by two orthogonal families of Euler beams. Pantographic rectangular 'long' waveguides are considered in which imposed boundary displacements can induce the onset of traveling (possibly non-linear) waves. We performed numerical simulations concerning a set of dynamically interesting cases. The system undergoes large rotations which may involve geometrical non-linearities, possibly opening the path to appealing phenomena such as propagation of solitary waves. Boundary conditions dramatically influence the transmission of the considered waves at discontinuity surfaces. The theoretical study of this kind of objects looks critical, as the concept of pantographic 2D sheets seems to have promising possible applications in a number of fields, e.g. acoustic filters, vascular prostheses and aeronautic/aerospace panels.

  8. F2D: A two dimensional compressible gas flow code

    The F2D computer code is a general-purpose, two-dimensional, fully compressible thermal-fluids code that models most phenomena found in experimental environments with coupled fluid flow and heat transfer. The code solves momentum, continuity, gas energy, and structure energy equations, simultaneously utilizing a predictor-corrector solution algorithm. The F2D code applied to a particle-bed reactor operating at 5 MW/L with a flow-control cold frit, revealed a skew in the temperature contours caused by two-dimensional flow effects. A thermal-fluid stability analysis of particle-bed and NERVA type reactors reveals similar behavior for the stability threshold

  9. Stable 2D Feature Tracking for Long Video Sequences

    Jong-Seung Park

    2008-12-01

    Full Text Available In this paper, we propose a 2D feature tracking method that is stable to long video sequences. To improve the stability of long tracking, we use trajectory information about 2D features. We predict the expected feature states and compute a rough estimate of the feature location on the current image frame using the history of previous feature states up to the current frame. A search window is positioned at the estimated location and similarity measures are computed within the search window. Once the feature position is determined from the similarity measures, the current feature states are appended to the history bu®er. The outlier rejection stage is also introduced to reduce false matches. Experimental results from real video sequences showed that the proposed method stably tracks point features for long frame sequences.

  10. 2D Models for Dust-driven AGB Star Winds

    Woitke, P

    2006-01-01

    New axisymmetric (2D) models for dust-driven winds of C-stars are presented which include hydrodynamics with radiation pressure on dust, equilibrium chemistry and time-dependent dust formation with coupled grey Monte Carlo radiative transfer. Considering the most simple case without stellar pulsation (hydrostatic inner boundary condition) these models reveal a more complex picture of the dust formation and wind acceleration as compared to earlier published spherically symmetric (1D) models. The so-called exterior $\\kappa$-mechanism causes radial oscillations with short phases of active dust formation between longer phases without appreciable dust formation, just like in the 1D models. However, in 2D geometry, the oscillations can be out-of-phase at different places above the stellar atmosphere which result in the formation of dust arcs or smaller caps that only occupy a certain fraction of the total solid angle. These dust structures are accelerated outward by radiation pressure, expanding radially and tangen...

  11. DEVELOPMENT OF 2D HUMAN BODY MODELING USING THINNING ALGORITHM

    K. Srinivasan

    2010-11-01

    Full Text Available Monitoring the behavior and activities of people in Video surveillance has gained more applications in Computer vision. This paper proposes a new approach to model the human body in 2D view for the activity analysis using Thinning algorithm. The first step of this work is Background subtraction which is achieved by the frame differencing algorithm. Thinning algorithm has been used to find the skeleton of the human body. After thinning, the thirteen feature points like terminating points, intersecting points, shoulder, elbow, and knee points have been extracted. Here, this research work attempts to represent the body model in three different ways such as Stick figure model, Patch model and Rectangle body model. The activities of humans have been analyzed with the help of 2D model for the pre-defined poses from the monocular video data. Finally, the time consumption and efficiency of our proposed algorithm have been evaluated.

  12. Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides

    Mak, Kin Fai; Shan, Jie

    2016-04-01

    Recent advances in the development of atomically thin layers of van der Waals bonded solids have opened up new possibilities for the exploration of 2D physics as well as for materials for applications. Among them, semiconductor transition metal dichalcogenides, MX2 (M = Mo, W; X = S, Se), have bandgaps in the near-infrared to the visible region, in contrast to the zero bandgap of graphene. In the monolayer limit, these materials have been shown to possess direct bandgaps, a property well suited for photonics and optoelectronics applications. Here, we review the electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties.

  13. MasterChem: cooking 2D-polymers.

    Rodríguez-San-Miguel, D; Amo-Ochoa, P; Zamora, F

    2016-03-01

    2D-polymers are still dominated by graphene and closely related materials such as boron nitride, transition metal sulphides and oxides. However, the rational combination of molecules with suitable design is already showing the high potential of chemistry in this new research field. The aim of this feature article is to illustrate, and provide some perspectives, the current state-of-the-art in the field of synthetic 2D-polymers showing different alternatives to prepare this novel type of polymers based on the rational use of chemistry. This review comprises a brief revision of the essential concepts, the strategies of preparation following the two general approaches, bottom-up and top-down, and a revision of the promising seminal properties showed by some of these nanomaterials. PMID:26790817

  14. Simulation of corium concrete interaction in 2D geometry

    Benchmarking work was recently performed for the issue of molten corium concrete interaction (MCCI). A synthesis is given here. It concerns first the 2D CCI-2 test with a homogeneous pool and a limestone concrete, which was used for a blind benchmark. Secondly, the COMET-L2 and COMET-L3 2D experiments in a stratified configuration were used as a post-test (L2) and a blind-test (L3) benchmark. More details are given here for the recent benchmark considering a matrix of four reactor cases, with both a homogeneous and a stratified configuration, and with both a limestone and a siliceous concrete. A short overview is given on the different models used in the codes, and the consistency between the benchmark actions on experiments and reactor situations is discussed. Finally, the major uncertainties concerning MCCI are also pointed out. (authors)

  15. Simulation of corium concrete interaction in 2D geometry

    Cranga, M. [IRSN, DPAM, F-13115 St Paul Les Durance (France); Spindler, B.; Dufour, E. [CEA Grenoble, DEN, F-38000 Grenoble (France); Dimov, Dimitar [Bulgarian Acad Sci, Inst Nucl Res and Nucl Energy, NPPSAL, BU-1784 Sofia (Bulgaria); Atkhen, Kresna [EDF, SEPTEN, F-69628 Villeurbanne (France); Foit, Jerzy [Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany); Garcia-Martin, M. [Univ Politecn Madrid, E-28006 Madrid (Spain); Sevon, Tuomo [Tech Res Ctr Finland VTT, FI-02044 Helsinki (Finland); Schmidt, W. [AREVA, D-91058 Erlangen (Germany); Spengler, C. [Gesell Anlagen and Reaktorsicherheit GRS mbH, D-50667 Cologne (Germany)

    2010-07-01

    Benchmarking work was recently performed for the issue of molten corium concrete interaction (MCCI). A synthesis is given here. It concerns first the 2D CCI-2 test with a homogeneous pool and a limestone concrete, which was used for a blind benchmark. Secondly, the COMET-L2 and COMET-L3 2D experiments in a stratified configuration were used as a post-test (L2) and a blind-test (L3) benchmark. More details are given here for the recent benchmark considering a matrix of four reactor cases, with both a homogeneous and a stratified configuration, and with both a limestone and a siliceous concrete. A short overview is given on the different models used in the codes, and the consistency between the benchmark actions on experiments and reactor situations is discussed. Finally, the major uncertainties concerning MCCI are also pointed out. (authors)

  16. Energy level transitions of gas in a 2D nanopore

    Grinyaev, Yurii V., E-mail: grn@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Chertova, Nadezhda V., E-mail: chertova@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Psakhie, Sergei G., E-mail: sp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    An analytical study of gas behavior in a 2D nanopore was performed. It is shown that the temperature dependence of gas energy can be stepwise due to transitions from one size-quantized subband to another. Taking into account quantum size effects results in energy level transitions governed by the nanopore size, temperature and gas density. This effect leads to an abrupt change of gas heat capacity in the nanopore at the above varying system parameters.

  17. 2D imaging of functional structures in perfused pig heart

    Kessler, Manfred D.; Cristea, Paul D.; Hiller, Michael; Trinks, Tobias

    2002-06-01

    In 2000 by 2D-imaging we were able for the first time to visualize in subcellular space functional structures of myocardium. For these experiments we used hemoglobin-free perfused pig hearts in our lab. Step by step we learned to understand the meaning of subcellular structures. Principally, the experiment revealed that in subcellular space very fast changes of light scattering can occur. Furthermore, coefficients of different parameters were determined on the basis of multicomponent system theory.

  18. Transport properties of 2D graphene containing structural defects

    Lherbier, Aurelien; Dubois, Simon M. -M.; Declerck, Xavier; Niquet, Yann-Michel; Roche, Stephan; Charlier, Jean-Christophe

    2012-01-01

    We propose an extensive report on the simulation of electronic transport in 2D graphene in presence of structural defects. Amongst the large variety of such defects in sp$^2$ carbon-based materials, we focus on the Stone-Wales defect and on two divacancy-type reconstructed defects. First, based on ab initio calculations, a tight-binding model is derived to describe the electronic structure of these defects. Then, semiclassical transport properties including the elastic mean free paths, mobili...

  19. 2-D constrained Navier-Stokes equation and intermediate asymptotics

    Caglioti, E.; Pulvirenti, M.; F. Rousset

    2008-01-01

    We introduce a modified version of the two-dimensional Navier-Stokes equation, preserving energy and momentum of inertia, which is motivated by the occurrence of different dissipation time scales and related to the gradient flow structure of the 2-D Navier-Stokes equation. The hope is to understand intermediate asymptotics. The analysis we present here is purely formal. A rigorous study of this equation will be done in a forthcoming paper.

  20. Research on metal atom evaporation with 2-D steady flows

    Study of the evaporation is one of crucial technology in AVLIS (atomic vapor laser isotopic separation). The research work on physical parameters of atomic vapor in separation region such as the 2-D distributions of velocity, density and temperature provides some important scientific data for designing separator in AVLIS engineering. The distribution of density, velocity and temperature is presented and some related interpretations for them are also given on the basis of BGK equation, when many absorbing boards are considered