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Sample records for psf-matched image subtraction

  1. A comparison of subtracted images from dental subtraction programs

    International Nuclear Information System (INIS)

    Han, Won Jeong

    2002-01-01

    To compare the standard deviation of gray levels on digital subtracted images obtained by different dental subtraction programs. Paired periapical films were taken at the lower premolar and molar areas of the phantoms involving human mandible. The bite registration group used Rinn XCP equipment and bite registration material, based on polyvinyl siloxane, for standardization. The no bite registration group used only Rinn XCP equipment. The periapical film images were digitized at 1200 dpi resolution and 256 gray levels by a flat bed scanner with transparency unit. Dental digital subtraction programs used for this study were Subtractor (Biomedisys Co., Korea) and Emago (Oral Diagnostic Systems, The Netherlands). To measure the similarities between the subtracted images, the standard deviations of the gray levels were obtained using a histogram of subtracted images, which were then analyzed statistically. Subtracted images obtained by using the Emago program without manual selection of corresponding points showed the lowest standard deviation of gray levels (p<0.01). And the standard deviation of gray levels was lower in subtracted images in the group of a bite registration than in the group of no use of bite registration (p<0.01). Digital radiographic subtraction without manual selection of reference points was found to be a convenient and superior method.

  2. X-ray image subtracting system

    International Nuclear Information System (INIS)

    Wesbey, W.H.; Keyes, G.S.; Georges, J.-P.J.

    1982-01-01

    An X-ray image subtracting system for making low contrast structures in the images more conspicuous is described. An X-ray source projects successive high and low energy X-ray beam pulses through a body and the resultant X-ray images are converted to optical images. Two image pick-up devices such as TV cameras that have synchronously operated shutters receive the alternate images and convert them to corresponding analog video signals. In some embodiments, the analog signals are converted to a matrix of digital pixel signals that are variously processed and subtracted and converted to signals for driving a TV monitor display and analog storage devices. In other embodiments the signals are processed and subtracted in analog form for display. The high and low energy pulses can follow each other immediately so good registration between subtracted images is obtainable even though the anatomy is in motion. The energy levels of the X-ray pulses are chosen to maximize the difference in attenuation between the anatomical structure which is to be subtracted out and that which remains. (author)

  3. Digital subtraction imaging in cardiac investigations

    International Nuclear Information System (INIS)

    Partridge, J.B.; Dickinson, D.F.

    1984-01-01

    The role of digital subtraction imaging (DSI) in the investigation of heart disease in patients of all ages, including neonates, was evaluated by the addition of a continuous fluoroscopy system to an existing, single-plane catheterisation laboratory. In some situations, DSI provided diagnostic images where conventional radiography could not and, in general, provided images of comparable quality to cineangiography. The total dose of contrast medium was usually less than that which would have been required for biplane cineangiography and the dose of radiation was always less. Digital subtraction imaging can make a significant contribution to the investigation of congenital heart disease and has some useful features in the study of acquired heart disease. (author)

  4. Subtracted versus non-subtracted digital imaging in peripheral angiography

    International Nuclear Information System (INIS)

    Fink, U.; Heywang, S.; Mayr, B.; Berger, H.

    1989-01-01

    Digital subtraction angiography (DSA) plays an important role in the management of vascular diseases of the lower extremities. A disadvantage is the lack of an automatically moving table top. We used a 1,024x1,024 matrix with a large-screen intensifier system and an automated 'stepping' facility. In 161 examinations of the arteries of the lower extremity digital peripheral arteriography was performed with and without the subtraction technique. We compared the influence of different iodine concentrations in DA and DSA. Peripheral DA proved to be equal to peripheral DSA in the region of the pelvis, thigh and knee, with no adequate contrasting being obtained merely in the region of the lower leg arteries in about 45%. It is necessary to use contrast medium at a concentration of 300 mg I/ml. The installation of an automated 'stepping' facility reduces the amount of contrast' medium needed and the exposure time. (orig.)

  5. Myocardial perfusion imaging by digital subtraction angiography

    International Nuclear Information System (INIS)

    Kadowaki, Hiroyuki; Ishikawa, Kinji; Ogai, Toshihiro; Katori, Ryo

    1986-01-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; 1) at the R wave of the electrocardiogram, 2) 100 msec before the R wave, and 3) 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery. In all patients with anterior myocardial infarction, low perfusion was observed at the infarcted portion compared to the non-infarcted myocardium. In patients with inferior myocardial infarction, this low perfusion area was not observed because right coronary angiography was not subjected to DSA in this study. (J.P.N.)

  6. [Myocardial perfusion imaging by digital subtraction angiography].

    Science.gov (United States)

    Kadowaki, H; Ishikawa, K; Ogai, T; Katori, R

    1986-03-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; at the R wave of the electrocardiogram, 100 msec before the R wave, and 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. A study of transverse image reconstruction with digital subtraction angiography

    International Nuclear Information System (INIS)

    Sakamoto, Kiyoshi; Kotoura, Noriko; Terasawa, Yuuji; Oda, Masahiko; Gotou, Hiroshi; Nasada, Toshiya; Tanooka, Masao

    1995-01-01

    For digital subtraction angiography (DSA) with C-type equipment, it is possible to radiate an X-ray during rotation and to collect data at different angular settings. We tried to reconstruct transverse image from data obtained by scanning DSA images at different angular settings. 88 projection data were obtained by rotating the object at 180deg during radiation. Reconstruction was made using the convolution method with pixel value distribution for each projection. Similarly, the image quality of the reconstructed images were compared with the unsubtracted and subtracted ones. In case a part object was outside the calculating region, artifacts were generally produced. However, the artifacts were reduced by subtracting the background from the image. In addition, the cupping phenomenon caused by beam hardening was relaxed and high-quality imaging could be achieved. This method will become even more effective, if we will use it with selective angiography in which the limited area is enhanced. (author)

  8. Subtraction and dynamic MR images of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Yoshitaka; Aoki, Manabu; Harada, Junta (Jikei Univ., Tokyo (Japan). School of Medicine)

    1993-04-01

    The purpose of this study was to evaluate the diagnostic effectiveness of subtraction and dynamic MR imaging in patients with breast masses. In 23 breast cancers and six fibroadenomas, spin echo T1 images were obtained at 0.2 Tesla before and every minute after intravenous injection of Gd-DTPA (0.1 or 0.2 mmol/kg). Subtraction images were obtained sequentially on the CRT monitor. All breast masses were enhanced after gadolinium and stood out as bright lesions on subtraction images. The tumor margin and its extension were more precisely evaluated on subtraction MR images than on conventional postcontrast MR images. Breast cancer showed a characteristic time-intensity curve with an early peak, in contrast to fibroadenoma, which showed a gradual increase in signal intensity. Subtraction MR imaging is a simple method for the evaluation of breast masses, and further, the time-intensity curve obtained by dynamic study is helpful in the differential diagnosis of lesions. (author).

  9. Appearance of the canine meninges in subtraction magnetic resonance images.

    Science.gov (United States)

    Lamb, Christopher R; Lam, Richard; Keenihan, Erin K; Frean, Stephen

    2014-01-01

    The canine meninges are not visible as discrete structures in noncontrast magnetic resonance (MR) images, and are incompletely visualized in T1-weighted, postgadolinium images, reportedly appearing as short, thin curvilinear segments with minimal enhancement. Subtraction imaging facilitates detection of enhancement of tissues, hence may increase the conspicuity of meninges. The aim of the present study was to describe qualitatively the appearance of canine meninges in subtraction MR images obtained using a dynamic technique. Images were reviewed of 10 consecutive dogs that had dynamic pre- and postgadolinium T1W imaging of the brain that was interpreted as normal, and had normal cerebrospinal fluid. Image-anatomic correlation was facilitated by dissection and histologic examination of two canine cadavers. Meningeal enhancement was relatively inconspicuous in postgadolinium T1-weighted images, but was clearly visible in subtraction images of all dogs. Enhancement was visible as faint, small-rounded foci compatible with vessels seen end on within the sulci, a series of larger rounded foci compatible with vessels of variable caliber on the dorsal aspect of the cerebral cortex, and a continuous thin zone of moderate enhancement around the brain. Superimposition of color-encoded subtraction images on pregadolinium T1- and T2-weighted images facilitated localization of the origin of enhancement, which appeared to be predominantly dural, with relatively few leptomeningeal structures visible. Dynamic subtraction MR imaging should be considered for inclusion in clinical brain MR protocols because of the possibility that its use may increase sensitivity for lesions affecting the meninges. © 2014 American College of Veterinary Radiology.

  10. Comparison of iodine K-edge subtraction and fluorescence subtraction imaging in an animal system

    International Nuclear Information System (INIS)

    Zhang, H.; Zhu, Y.; Bewer, B.; Zhang, L.; Korbas, M.; Pickering, I.J.; George, G.N.; Gupta, M.; Chapman, D.

    2008-01-01

    K-Edge Subtraction (KES) utilizes the discontinuity in the X-ray absorption across the absorption edge of the selected contrast element and creates an image of the projected density of the contrast element from two images acquired just above and below the K-edge of the contrast element. KES has proved to be powerful in coronary angiography, micro-angiography, bronchography, and lymphatic imaging. X-ray fluorescence imaging is a successful technique for the detection of dilute quantities of elements in specimens. However, its application at high X-ray energies (e.g. at the iodine K-edge) is complicated by significant Compton background, which may enter the energy window set for the contrast material's fluorescent X-rays. Inspired by KES, Fluorescence Subtraction Imaging (FSI) is a technique for high-energy (>20 keV) fluorescence imaging using two different incident beam energies just above and below the absorption edge of a contrast element (e.g. iodine). The below-edge image can be assumed as a 'background' image, which includes Compton scatter and fluorescence from other elements. The above-edge image will contain nearly identical spectral content as the below-edge image but will contain the additional fluorescence of the contrast element. This imaging method is especially promising with thick objects with dilute contrast materials, significant Compton background, and/or competing fluorescence lines from other materials. A quality factor is developed to facilitate the comparison. The theoretical value of the quality factor sets the upper limit that an imaging method can achieve when the noise is Poisson limited. The measured value of this factor makes two or more imaging methods comparable. Using the Hard X-ray Micro-Analysis (HXMA) beamline at the Canadian Light Source (CLS), the techniques of FSI and KES were critically compared, with reference to radiation dose, image acquisition time, resolution, signal-to-noise ratios, and quality factor

  11. A method for dynamic subtraction MR imaging of the liver

    Directory of Open Access Journals (Sweden)

    Setti Ernesto

    2006-06-01

    Full Text Available Abstract Background Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time. Methods Nineteen consecutive patients (median age 45 years; range 37–67 were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20°, slice thickness 1.5 mm acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a rigid 3D translation using maximization of normalized mutual information (NMI, and (b fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI. Results The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 ± 0.031 vs. 0.078 ± 0.031, n.s., paired t-test and by a further 23% (0.096 ± 0.035 vs. 0.078 ± 0.031, p t-test after non-rigid realignment. The overall average NMI increase was 31%. Conclusion This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions.

  12. Real-time digital x-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.; Kruger, R.A.; Houk, T.L.

    1982-01-01

    A method of producing visible difference images derived from an x-ray image of an anatomical subject is described. X-rays are directed through the subject, and the image is converted into television fields comprising trains of analog video signals. The analog signals are converted into digital signals, which are then integrated over a predetermined time corresponding to several television fields. Difference video signals are produced by performing a subtraction between the ongoing video signals and the corresponding integrated signals, and are converted into visible television difference images representing changes in the x-ray image

  13. Iodine filter imaging system for subtraction angiography using synchrotron radiation

    Science.gov (United States)

    Umetani, K.; Ueda, K.; Takeda, T.; Itai, Y.; Akisada, M.; Nakajima, T.

    1993-11-01

    A new type of real-time imaging system was developed for transvenous coronary angiography. A combination of an iodine filter and a single energy broad-bandwidth X-ray produces two-energy images for the iodine K-edge subtraction technique. X-ray images are sequentially converted to visible images by an X-ray image intensifier. By synchronizing the timing of the movement of the iodine filter into and out of the X-ray beam, two output images of the image intensifier are focused side by side on the photoconductive layer of a camera tube by an oscillating mirror. Both images are read out by electron beam scanning of a 1050-scanning-line video camera within a camera frame time of 66.7 ms. One hundred ninety two pairs of iodine-filtered and non-iodine-filtered images are stored in the frame memory at a rate of 15 pairs/s. In vivo subtracted images of coronary arteries in dogs were obtained in the form of motion pictures.

  14. Subtraction imaging of the ECG gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Tanegashima, K.; Fukui, M.; Hyodo, H.

    1987-05-01

    The subtracting manipulation of contrast-enhanced gated cardiac CT (GCCT) images was experimentally studied with TCT 60A - 30 type (Toshiba) for clinical use, thereby reducing the amount of contrast medium (CM). Initially the optimum relationship between the concentration of CM and its injected velocity was determined using the model of resected canine hearts and in actual dogs. The emphasized good-subtracted images were obtained when the difference of CT values was approximately 40 H.U. between cardiac cavity and myocardium. Such condition was feasible in the use of 25 % Diatrizoic acid and its injected velocity of 0.02 ml/kg/sec. Finally the reduction of the amount of CM by 1/3 became possible in clinical settings. The method is applicable to multi-slice GCCT in various heart diseases.

  15. IMPROVED BACKGROUND SUBTRACTION FOR THE SLOAN DIGITAL SKY SURVEY IMAGES

    International Nuclear Information System (INIS)

    Blanton, Michael R.; Kazin, Eyal; Muna, Demitri; Weaver, Benjamin A.; Price-Whelan, Adrian

    2011-01-01

    We describe a procedure for background subtracting Sloan Digital Sky Survey (SDSS) imaging that improves the resulting detection and photometry of large galaxies on the sky. Within each SDSS drift scan run, we mask out detected sources and then fit a smooth function to the variation of the sky background. This procedure has been applied to all SDSS-III Data Release 8 images, and the results are available as part of that data set. We have tested the effect of our background subtraction on the photometry of large galaxies by inserting fake galaxies into the raw pixels, reanalyzing the data, and measuring them after background subtraction. Our technique results in no size-dependent bias in galaxy fluxes up to half-light radii r 50 ∼ 100 arcsec; in contrast, for galaxies of that size the standard SDSS photometric catalog underestimates fluxes by about 1.5 mag. Our results represent a substantial improvement over the standard SDSS catalog results and should form the basis of any analysis of nearby galaxies using the SDSS imaging data.

  16. Real-time digital x-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.

    1982-01-01

    The invention provides a method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through the anatomical subject for producing an image, converting the image into television fields comprising trains of on-going video signals, digitally storing and integrating the on-going video signals over a time interval corresponding to several successive television fields and thereby producing stored and integrated video signals, recovering the video signals from storage and producing integrated video signals, producing video difference signals by performing a subtraction between the integrated video signals and the on-going video signals outside the time interval, and converting the difference signals into visible television difference images representing on-going changes in the X-ray image

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

    International Nuclear Information System (INIS)

    Yu Jianming; Lei Ziqiao; Kong Xiangchuang

    2006-01-01

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

  18. Real-time digital X-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.; Kruger, R.A.; Houk, T.L.

    1979-01-01

    A diagnostic anatomical X-ray apparatus comprising a converter and a television camera for converting an X-ray image of a subject into a series of television fields of video signals is described in detail. A digital memory system stores and integrates the video signals over a time interval corresponding to a plurality of successive television fields. The integrated video signals are recovered from storage and fed to a digital or analogue subtractor, the resulting output being displayed on a television monitor. Thus the display represents on-going changes in the anatomical X-ray image. In a modification, successive groups of fields are stored and integrated in three memories, cyclically, and subtractions are performed between successive pieces of integrated signals to provide a display of successive alterations in the X-ray image. For investigations of the heart, the integrating interval should be of the order of one cardiac cycle. (author)

  19. Image noise reduction algorithm for digital subtraction angiography: clinical results.

    Science.gov (United States)

    Söderman, Michael; Holmin, Staffan; Andersson, Tommy; Palmgren, Charlotta; Babic, Draženko; Hoornaert, Bart

    2013-11-01

    To test the hypothesis that an image noise reduction algorithm designed for digital subtraction angiography (DSA) in interventional neuroradiology enables a reduction in the patient entrance dose by a factor of 4 while maintaining image quality. This clinical prospective study was approved by the local ethics committee, and all 20 adult patients provided informed consent. DSA was performed with the default reference DSA program, a quarter-dose DSA program with modified acquisition parameters (to reduce patient radiation dose exposure), and a real-time noise-reduction algorithm. Two consecutive biplane DSA data sets were acquired in each patient. The dose-area product (DAP) was calculated for each image and compared. A randomized, blinded, offline reading study was conducted to show noninferiority of the quarter-dose image sets. Overall, 40 samples per treatment group were necessary to acquire 80% power, which was calculated by using a one-sided α level of 2.5%. The mean DAP with the quarter-dose program was 25.3% ± 0.8 of that with the reference program. The median overall image quality scores with the reference program were 9, 13, and 12 for readers 1, 2, and 3, respectively. These scores increased slightly to 12, 15, and 12, respectively, with the quarter-dose program imaging chain. In DSA, a change in technique factors combined with a real-time noise-reduction algorithm will reduce the patient entrance dose by 75%, without a loss of image quality. RSNA, 2013

  20. The contribution of chemical shift imaging with digital subtracting images to the diagnosis of steatohepatitis

    International Nuclear Information System (INIS)

    Guo Xinghua; Wang Juanping; Zhang Chongjie; Zheng Guofang; Fan Ruiqiang; Zhu Sumei; Liu Qiwang

    2006-01-01

    Objective: To investigate the diagnosis value of chemical shift imaging with digital subtracting in steatohepatitis. Methods: The in-phase images were subtracted by the out-phase ones in 34 cases of steatohepatitis, and the CNR were measured on these subtracted images to estimate the steatosis of the liver. The relationship of CT grade of steatohepatitis and CNR from the subtracted images was analyzed to evaluate the relationship between CNR and the degree of hepatic steatosis. The sensitivity and specificity of the subtracting and eyeballing methods were compared with chi-square test. Results: On the subtracted images, the liver and spleen were seen nearly the same aspects as low signals, CNR=0.98±0.06, meanwhile the spongy vertebra and the subcutaneous or abdominal lipid were seen as obvious higher signals in 52 normal cases. On the 34 steatohepatitis, scattered high signals were seen in the liver, which made the signal of liver higher than that of spleen, CNR=3.25±0.91--14.35±6.10. There was positive correlation between CNR and CT grade in the 34 cases of steatohepatitis, r=0.893, P<0.01. The sensitivity and specificity of the subtracting method were 88.24% and 94. 23%, significantly higher than that of the eyeballing results, 32.35% and 80.77%, P<0.01 and P<0.05. Conclusion: Chemical shift imaging with digital subtracting is a sensitive, specific, objective method to diagnose steatohepatitis and it is of potential ability for quantitative diagnosis. (authors)

  1. Utility of noise addition image made by using water phantom and image addition and subtraction software

    International Nuclear Information System (INIS)

    Watanabe, Ryo; Aoki, Takahiro; Hayano, Mizuho; Ogawa, Masato; Mituzono, Hiroki; Watanabe, Yuka

    2010-01-01

    In optimizing exposures, it is very important to evaluate the impact of image noise on image quality. To realize this, there is a need to evaluate how much image noise will make the subject disease invisible. But generally it is very difficult to shoot images of different quality in a clinical examination. Thus, a method to create a noise addition image by adding the image noise to raw data has been reported. However, this approach requires a special system, so it is difficult to implement in many facilities. We have invented a method to easily create a noise addition image by using the water phantom and image add-subtract software that accompanies the device. To create a noise addition image, first we made a noise image by subtracting the water phantom with different standard deviation (SD). A noise addition image was then created by adding the noise image to the original image. By using this method, a simulation image with intergraded SD can be created from the original. Moreover, the noise frequency component of the created noise addition image is as same as the real image. Thus, the relationship of image quality to SD in the clinical image can be evaluated. Although this method is an easy method of LDSI creation on image data, a noise addition image can be easily created by using image addition and subtraction software and water phantom, and this can be implemented in many facilities. (author)

  2. Multinuclide digital subtraction imaging in symptomatic prostnetic joints

    International Nuclear Information System (INIS)

    Chafetz, N.; Hattner, R.S.; Ruarke, W.C.; Helms, C.A.; Genant, H.K.; Murray, W.R.

    1985-01-01

    One hundred eleven patients with symptomatic prosthetic joints (86 hips, 23 knees, and two shoulders) were evaluated for prosthetic loosening and infection by combined technetium-99m-MDP/gallium-67 digital subtraction imaging. Clinical correlation was based on the assessment of loosening and bacterial cultures obtained at the time of surgery in 54 patients, joint aspiration cultures obtained in 37 patients, and long-term clinical follow-up for greater than 1.5 years in an additional 15 patients. Results revealed an 80-90% predictive value of a positive test for loosening, and a 95% predictive value of a negative test for infection. However, because of the low sensitivities and specificities observed, this approach to the evaluation of symptomatic prosthetic joints does not seem cost effective

  3. A new registration method with voxel-matching technique for temporal subtraction images

    Science.gov (United States)

    Itai, Yoshinori; Kim, Hyoungseop; Ishikawa, Seiji; Katsuragawa, Shigehiko; Doi, Kunio

    2008-03-01

    A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes on medical images by removing most of normal structures. One of the important problems in temporal subtraction is that subtraction images commonly include artifacts created by slight differences in the size, shape, and/or location of anatomical structures. In this paper, we developed a new registration method with voxel-matching technique for substantially removing the subtraction artifacts on the temporal subtraction image obtained from multiple-detector computed tomography (MDCT). With this technique, the voxel value in a warped (or non-warped) previous image is replaced by a voxel value within a kernel, such as a small cube centered at a given location, which would be closest (identical or nearly equal) to the voxel value in the corresponding location in the current image. Our new method was examined on 16 clinical cases with MDCT images. Preliminary results indicated that interval changes on the subtraction images were enhanced considerably, with a substantial reduction of misregistration artifacts. The temporal subtraction images obtained by use of the voxel-matching technique would be very useful for radiologists in the detection of interval changes on MDCT images.

  4. Preliminary study of lateral cerebral angiography with reverse rotation in the digital image registration and subtraction

    International Nuclear Information System (INIS)

    Shen Zhenglin; Liu Dongyang; Shen Zhenghai; Li Shuping; Zhang Ziyan; Wu Yongjuan; Liu Peijun

    2012-01-01

    Objective: Investigate the value and feasibility of image registration with reverse rotation in lateral cerebral DSA. Methods: (1) Experimental study: the target images were subtracted directly, and subtracted again after reverse rotation. Software of registration and subtraction with reverse rotation edited by the author utilizing Visual Basic. The function of the automatic angle detection by the software were evaluated to see whether it detected the angle of line. The subtraction function of DSA by the software was evaluated. (2) Clinical retrospective study: the untreated mask and target images of 15 patients with motion along vertical axis during lateral cerebral DSA were uploaded to the software. The target images were processed with and without the software to get two sets of images. (3) Evaluation: four experienced radiologists read and compared the two sets of the images,and graded their findings. Results: (1) The automatic detection by the software suggested that the target images should be rotated counterclockwise 1.3°. The subtraction result of the software was satisfactory. (2) In the 15 sets of images, there were only three sets of images deemed optimal after traditional subtraction. After reverse rotation, artifacts were significantly reduced and the image sharper. There were ten cases with significant artifacts after traditional subtraction, and those images were sharper and showed more peripheral vessels after reverse rotation. The traditional subtraction images of two sets could not be interpreted,the reverse rotation registration images reached the diagnostic quality. (3) Subjective evaluation: there were more information and less noise and distortion in the registration images with reverse rotation than in the traditional subtraction. But the image resolution decreased slightly after reverse rotation registration. Conclusion: The registration of digital angiography with reverse rotation can improve the image quality in lateral cerebral DSA

  5. Incidence of ischemic lesions in diffusion-weighted imaging after transbrachial digital subtraction angiography

    International Nuclear Information System (INIS)

    Aschenbach, R.; Majeed, A.; Eger, C.; Basche, S.; Kerl, J.M.; Vogl, T.J.

    2008-01-01

    Purpose: to evaluate the frequency of ischemia after transbrachial digital subtraction angiography under ambulant conditions using diffusion-weighted imaging. Materials and methods: 200 patients were included in a prospective study design and received transbrachial digital subtraction angiography under ambulant conditions. Before and after digital subtraction angiography, diffusion-weighted imaging of the brain was performed. Results: in our study population no new lesions were found in diffusion-weighted imaging after digital subtraction angiography during the 3-hour window after angiography. One new lesion was found 3 days after angiography as a late onset complication. Therefore, the frequency of neurological complications is at the level of the confidence interval of 0 - 1.5%. Conclusion: the transbrachial approach under ambulant conditions is a safe method for digital subtraction angiography resulting in a low rate of ischemic lesions in diffusion-weighted imaging. (orig.)

  6. A temporal subtraction method for thoracic CT images based on generalized gradient vector flow

    International Nuclear Information System (INIS)

    Miyake, Noriaki; Kim, H.; Maeda, Shinya; Itai, Yoshinori; Tan, J.K.; Ishikawa, Seiji; Katsuragawa, Shigehiko

    2010-01-01

    A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes (such as formation of new lesions and changes in existing abnormalities) on medical images by removing most of the normal structures. If image registration is incorrect, not only the interval changes but also the normal structures would be appeared as some artifacts on the temporal subtraction image. In a temporal subtraction technique for 2-D X-ray image, the effectiveness is shown through a lot of clinical evaluation experiments, and practical use is advancing. Moreover, the MDCT (Multi-Detector row Computed Tomography) can easily introduced on medical field, the development of a temporal subtraction for thoracic CT Images is expected. In our study, a temporal subtraction technique for thoracic CT Images is developed. As the technique, the vector fields are described by use of GGVF (Generalized Gradient Vector Flow) from the previous and current CT images. Afterwards, VOI (Volume of Interest) are set up on the previous and current CT image pairs. The shift vectors are calculated by using nearest neighbor matching of the vector fields in these VOIs. The search kernel on previous CT image is set up from the obtained shift vector. The previous CT voxel which resemble standard the current voxel is detected by voxel value and vector of the GGVF in the kernel. And, the previous CT image is transformed to the same coordinate of standard voxel. Finally, temporal subtraction image is made by subtraction of a warping image from a current one. To verify the proposal method, the result of application to 7 cases and the effectiveness are described. (author)

  7. 3D temporal subtraction on multislice CT images using nonlinear warping technique

    Science.gov (United States)

    Ishida, Takayuki; Katsuragawa, Shigehiko; Kawashita, Ikuo; Kim, Hyounseop; Itai, Yoshinori; Awai, Kazuo; Li, Qiang; Doi, Kunio

    2007-03-01

    The detection of very subtle lesions and/or lesions overlapped with vessels on CT images is a time consuming and difficult task for radiologists. In this study, we have developed a 3D temporal subtraction method to enhance interval changes between previous and current multislice CT images based on a nonlinear image warping technique. Our method provides a subtraction CT image which is obtained by subtraction of a previous CT image from a current CT image. Reduction of misregistration artifacts is important in the temporal subtraction method. Therefore, our computerized method includes global and local image matching techniques for accurate registration of current and previous CT images. For global image matching, we selected the corresponding previous section image for each current section image by using 2D cross-correlation between a blurred low-resolution current CT image and a blurred previous CT image. For local image matching, we applied the 3D template matching technique with translation and rotation of volumes of interests (VOIs) which were selected in the current and the previous CT images. The local shift vector for each VOI pair was determined when the cross-correlation value became the maximum in the 3D template matching. The local shift vectors at all voxels were determined by interpolation of shift vectors of VOIs, and then the previous CT image was nonlinearly warped according to the shift vector for each voxel. Finally, the warped previous CT image was subtracted from the current CT image. The 3D temporal subtraction method was applied to 19 clinical cases. The normal background structures such as vessels, ribs, and heart were removed without large misregistration artifacts. Thus, interval changes due to lung diseases were clearly enhanced as white shadows on subtraction CT images.

  8. Improvement of temporal and dynamic subtraction images on abdominal CT using 3D global image matching and nonlinear image warping techniques

    International Nuclear Information System (INIS)

    Okumura, E; Sanada, S; Suzuki, M; Takemura, A; Matsui, O

    2007-01-01

    Accurate registration of the corresponding non-enhanced and arterial-phase CT images is necessary to create temporal and dynamic subtraction images for the enhancement of subtle abnormalities. However, respiratory movement causes misregistration at the periphery of the liver. To reduce these misregistration errors, we developed a temporal and dynamic subtraction technique to enhance small HCC by 3D global matching and nonlinear image warping techniques. The study population consisted of 21 patients with HCC. Using the 3D global matching and nonlinear image warping technique, we registered current and previous arterial-phase CT images or current non-enhanced and arterial-phase CT images obtained in the same position. The temporal subtraction image was obtained by subtracting the previous arterial-phase CT image from the warped current arterial-phase CT image. The dynamic subtraction image was obtained by the subtraction of the current non-enhanced CT image from the warped current arterial-phase CT image. The percentage of fair or superior temporal subtraction images increased from 52.4% to 95.2% using the new technique, while on the dynamic subtraction images, the percentage increased from 66.6% to 95.2%. The new subtraction technique may facilitate the diagnosis of subtle HCC based on the superior ability of these subtraction images to show nodular and/or ring enhancement

  9. Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging

    Energy Technology Data Exchange (ETDEWEB)

    Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V. (Mt. Sinai Medical Center, New York, NY (USA))

    1989-09-01

    Blood-pool subtraction has been proposed to enhance {sup 111}In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging.

  10. Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging

    International Nuclear Information System (INIS)

    Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V.

    1989-01-01

    Blood-pool subtraction has been proposed to enhance 111 In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging

  11. Two-dimensional real-time imaging system for subtraction angiography using an iodine filter

    Science.gov (United States)

    Umetani, Keiji; Ueda, Ken; Takeda, Tohoru; Anno, Izumi; Itai, Yuji; Akisada, Masayoshi; Nakajima, Teiichi

    1992-01-01

    A new type of subtraction imaging system was developed using an iodine filter and a single-energy broad bandwidth monochromatized x ray. The x-ray images of coronary arteries made after intravenous injection of a contrast agent are enhanced by an energy-subtraction technique. Filter chopping of the x-ray beam switches energies rapidly, so that a nearly simultaneous pair of filtered and nonfiltered images can be made. By using a high-speed video camera, a pair of two 512 × 512 pixel images can be obtained within 9 ms. Three hundred eighty-four images (raw data) are stored in a 144-Mbyte frame memory. After phantom studies, in vivo subtracted images of coronary arteries in dogs were obtained at a rate of 15 images/s.

  12. Detection of pulmonary nodules on lung X-ray images. Studies on multi-resolutional filter and energy subtraction images

    International Nuclear Information System (INIS)

    Sawada, Akira; Sato, Yoshinobu; Kido, Shoji; Tamura, Shinichi

    1999-01-01

    The purpose of this work is to prove the effectiveness of an energy subtraction image for the detection of pulmonary nodules and the effectiveness of multi-resolutional filter on an energy subtraction image to detect pulmonary nodules. Also we study influential factors to the accuracy of detection of pulmonary nodules from viewpoints of types of images, types of digital filters and types of evaluation methods. As one type of images, we select an energy subtraction image, which removes bones such as ribs from the conventional X-ray image by utilizing the difference of X-ray absorption ratios at different energy between bones and soft tissue. Ribs and vessels are major causes of CAD errors in detection of pulmonary nodules and many researches have tried to solve this problem. So we select conventional X-ray images and energy subtraction X-ray images as types of images, and at the same time select ∇ 2 G (Laplacian of Guassian) filter, Min-DD (Minimum Directional Difference) filter and our multi-resolutional filter as types of digital filters. Also we select two evaluation methods and prove the effectiveness of an energy subtraction image, the effectiveness of Min-DD filter on a conventional X-ray image and the effectiveness of multi-resolutional filter on an energy subtraction image. (author)

  13. Digital image comparison by subtracting contextual transformations—percentile rank order differentiation

    Science.gov (United States)

    Wehde, M. E.

    1995-01-01

    The common method of digital image comparison by subtraction imposes various constraints on the image contents. Precise registration of images is required to assure proper evaluation of surface locations. The attribute being measured and the calibration and scaling of the sensor are also important to the validity and interpretability of the subtraction result. Influences of sensor gains and offsets complicate the subtraction process. The presence of any uniform systematic transformation component in one of two images to be compared distorts the subtraction results and requires analyst intervention to interpret or remove it. A new technique has been developed to overcome these constraints. Images to be compared are first transformed using the cumulative relative frequency as a transfer function. The transformed images represent the contextual relationship of each surface location with respect to all others within the image. The process of differentiating between the transformed images results in a percentile rank ordered difference. This process produces consistent terrain-change information even when the above requirements necessary for subtraction are relaxed. This technique may be valuable to an appropriately designed hierarchical terrain-monitoring methodology because it does not require human participation in the process.

  14. Quantitative analysis of planar technetium-99m-sestamibi myocardial perfusion images using modified background subtraction

    International Nuclear Information System (INIS)

    Koster, K.; Wackers, F.J.; Mattera, J.A.; Fetterman, R.C.

    1990-01-01

    Standard interpolative background subtraction, as used for thallium-201 ( 201 Tl), may create artifacts when applied to planar technetium-99m-Sestamibi ( 99m Tc-Sestamibi) images, apparently because of the oversubtraction of relatively high extra-cardiac activity. A modified background subtraction algorithm was developed and compared to standard background subtraction in 16 patients who had both exercise-delayed 201 Tl and exercise-rest 99m Tc-Sestamibi imaging. Furthermore, a new normal data base was generated. Normal 99m Tc-Sestamibi distribution was slightly different compared to 201 Tl. Using standard background subtraction, mean defect reversibility was significantly underestimated by 99m Tc-Sestamibi compared to 201 Tl (2.8 +/- 4.9 versus -1.8 +/- 8.4, p less than 0.05). Using the modified background subtraction, mean defect reversibility on 201 Tl and 99m Tc-Sestamibi images was comparable (2.8 +/- 4.9 versus 1.7 +/- 5.2, p = NS). We conclude, that for quantification of 99m Tc-Sestamibi images a new normal data base, as well as a modification of the interpolative background subtraction method should be employed to obtain quantitative results comparable to those with 201 Tl

  15. Tumor scintigraphy by the method for subtracting the initial image with technetium-99m labeled antibody

    International Nuclear Information System (INIS)

    Karube, Yoshiharu; Katsuno, Kentaro; Ito, Sanae; Matsunaga, Kazuhisa; Takata, Jiro; Kuroki, Masahide; Murakami, Masaaki; Matsuoka, Yuji

    1999-01-01

    The method for subtracting the initial image from the localization image was evaluated for radioimmunoscintigraphy of tumors with technetium-99m (Tc-99m) labeled antibodies. Monoclonal antibodies were parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, both of which have been found to discriminate CEA in tumor tissues from the CEA-related antigens. After reduction of the intrinsic disulfide bonds, these antibodies were labeled with Tc-99m. In vivo studies were performed on athymic nude mice bearing the human CEA-producing gastric carcinoma xenografts. Though biodistribution results showed selective and progressive accumulation of Tc-99m labeled antibodies at the tumor site, high radioactivity in blood was inappropriate for scintigraphic visualization of the tumors within a few hours. We examined the subtraction of the initial Tc-99m image from the Tc-99m localization image after a few hours. Subtracted images of the same count reflected the in vivo behavior of the Tc-99m radioactivity. The subtracted scintigrams revealed excellent tumor images with no significant extrarenal background. Visualization of the tumor site was dependent on antigen-specific binding and nonspecific exudation. These results demonstrate that a method of subtraction of the initial image may serve as a potentially useful diagnostic method for an abnormal site for agents with a low pharmacokinetic value. (author)

  16. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures.

    Science.gov (United States)

    Szucs-Farkas, Zsolt; Lautenschlager, Katrin; Flach, Patricia M; Ott, Daniel; Strautz, Tamara; Vock, Peter; Ruder, Thomas D

    2011-08-01

    To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p=0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p=0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, prib fractures. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  17. Late iodine enhancement computed tomography with image subtraction for assessment of myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Kouchi, Takanori; Fukuyama, Naoki; Yokoi, Takahiro; Miyagawa, Masao; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon City, Ehime (Japan); Uetani, Teruyoshi [Department of Cardiology, Ehime University Graduate School of Medicine, Toon City, Ehime (Japan); Yamashita, Natsumi [National Hospital Organization Shikoku Cancer Center, Department of Clinical Biostatistics, Section of Cancer Prevention and Epidemiology, Clinical Research Center, Matsuyama City, Ehime (Japan)

    2018-03-15

    To evaluate the feasibility of image subtraction in late iodine enhancement CT (LIE-CT) for assessment of myocardial infarction (MI). A comprehensive cardiac CT protocol and late gadolinium enhancement MRI (LGE-MRI) was used to assess coronary artery disease in 27 patients. LIE-CT was performed after stress CT perfusion (CTP) and CT angiography. Subtraction LIE-CT was created by subtracting the mask volume of the left ventricle (LV) cavity from the original LIE-CT using CTP dataset. The %MI volume was quantified as the ratio of LIE to entire LV volume, and transmural extent (TME) of LIE was classified as 0%, 1-24%, 25-49%, 50-74% or 75-100%. These results were compared with LGE-MRI using the Spearman rank test, Bland-Altman method and chi-square test. One hundred twenty-five (29%) of 432 segments were positive on LGE-MRI. Correlation coefficients for original and subtraction LIE-CT to LGE-MRI were 0.79 and 0.85 for %MI volume. Concordances of the 5-point grading scale between original and subtraction LIE-CT with LGE-MRI were 75% and 84% for TME; concordance was significantly improved using the subtraction technique (p <0.05). Subtraction LIE-CT allowed more accurate assessment of MI extent than the original LIE-CT. (orig.)

  18. Clinical application of subtraction CT imaging for evaluation of pulmonary vascular permeability

    International Nuclear Information System (INIS)

    Kato, Shiro; Asai, Toshihiko; Yatagai, Shigeo; Oonuma, Noboru; Ohno, Kunihiko; Nakamoto, Takaaki; Iizuka, Masahiko

    1991-01-01

    In this clinical study, one normal subject, one patient with primary interstitial pneumonia, one patient with segmental pneumonia due to Staphylococcus aureus, one patient with post-operative esophageal carcinoma, and two patients with mitral stenosis were studied. Dynamic CT scan images under continuous injection of low osmotic contrast medium were analyzed in series, in an attempt to evaluate vascular permeability quantitatively. The following results were obtained. Subtraction CT scan image 10 minutes after the start of contrast medium injection in two patients with pneumonia, showed a reduction of pulmonary vascular permeability following therapy. Subtraction CT scan image of the patient with post-operative esophageal carcinoma treated with 25 Gy radiation showed a discrepancy between pulmonary vascular permeability and other findings. In hemodynamically stable patients with mitral stenosis, subtraction CT images demonstrated that pulmonary vascular permeability was not affected by pulmonary congestion, irrespective of its severity. (author)

  19. Procedures for imaging of hemodialysis fistulas with particular reference to digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Neufang, K.F.R.; Erasmi-Koerber, H.; Wimmer, G.; Koeln Univ.

    1983-01-01

    All angiographic procedures established for imaging of hemodialysis fistulas, such as direct venous angiography, intravenous subtraction angiography and arteriography by direct puncture of the brachial artery of by Seldinger's transfemoral technique, can also be effected with digital image processing. Depending on the angiographic technique, the use of digital subtraction angiography has several advantages: lower doses and concentrations of the contrast agent, lower risk of complications (thrombosis of the fistula, vasospasm) and freedom from pain. In addition, there is a marked reduction of examination time and film cost. (orig.)

  20. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures

    Energy Technology Data Exchange (ETDEWEB)

    Szucs-Farkas, Zsolt, E-mail: zsolt.szuecs@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Lautenschlager, Katrin, E-mail: katrin@students.unibe.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Flach, Patricia M., E-mail: patricia.flach@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ott, Daniel, E-mail: daniel.ott@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Strautz, Tamara, E-mail: tamara.strautz@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Vock, Peter, E-mail: peter.vock@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ruder, Thomas D., E-mail: thomas.ruder@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland)

    2011-08-15

    Objective: To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. Materials and methods: In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. Results: The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p = 0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p = 0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, p < 0.001). Conclusions: Despite a better image quality, adding ES bone images to standard radiographs of the chest does not provide better sensitivity or improved diagnostic confidence in the detection of rib fractures.

  1. Clinical utility of Gd-DTPA subtraction MR imaging for spinal bone metastasis

    International Nuclear Information System (INIS)

    Ando, Keiichi; Murakami, Masao; Kuroda, Yasumasa

    1993-01-01

    Based on reports that Gd-DTPA contributes to the detection of tumors, we used it in 31 cases (97 lesions) of spinal bone metastases. The result was that Gd-DTPA increased the intensity of tumors and the surrounding bone marrow to almost the same level in 53%. To show the metastases clearly, an existing subtraction command system was utilized. The technique included the pixel-by-pixel method, to obtain a Gd-DTPA T1-weighted image (T1WI) subtracted by the original T1WI. The detectability of the subtraction image was improved up to 96%, but was less than the original T1WI (99%). Because of the different imaging rationale between two methods, a means to assess the quality of diagnosis must be proposed. To check the normal background, the same kind of postprocessing was performed in 21 patients without malignancy. Gd-DTPA prefusion was highest in the paravertebral veins, moderate in muscles and epidural fat, and lowest in the spinal cord, intervertebral disk and bone cortex. Gd-DTPA enhanced subtraction MR imaging provides a new diagnostic tool to detect and to assess bone metastasis. (author)

  2. A Feature Subtraction Method for Image Based Kinship Verification under Uncontrolled Environments

    DEFF Research Database (Denmark)

    Duan, Xiaodong; Tan, Zheng-Hua

    2015-01-01

    The most fundamental problem of local feature based kinship verification methods is that a local feature can capture the variations of environmental conditions and the differences between two persons having a kin relation, which can significantly decrease the performance. To address this problem...... the feature distance between face image pairs with kinship and maximize the distance between non-kinship pairs. Based on the subtracted feature, the verification is realized through a simple Gaussian based distance comparison method. Experiments on two public databases show that the feature subtraction method...

  3. Evaluation of carotid vessel wall enhancement with image subtraction after gadobenate dimeglumine-enhanced MR angiography

    International Nuclear Information System (INIS)

    Sardanelli, Francesco; Di Leo, Giovanni; Aliprandi, Alberto; Flor, Nicola; Papini, Giacomo D.E.; Roccatagliata, Luca; Cotticelli, Biagio; Nano, Giovanni; Cornalba, Gianpaolo

    2009-01-01

    Objectives: This study was aimed at testing the value of image subtraction for evaluating carotid vessel wall enhancement in contrast-enhanced MR angiography (MRA). Materials and methods: IRB approval was obtained. The scans of 81 consecutive patients who underwent carotid MRA with 0.1 mmol/kg of gadobenate dimeglumine were reviewed. Axial carotid 3D T1-weighted fast low-angle shot sequence before and 3 min after contrast injection were acquired and subtracted (enhanced minus unenhanced). Vessel wall enhancement was assigned a four-point score using native or subtracted images from 0 (no enhancement) to 3 (strong enhancement). Stenosis degree was graded according to NASCET. Results: With native images, vessel wall enhancement was detected in 20/81 patients (25%) and in 20/161 carotids (12%), and scored 2.0 ± 0.6 (mean ± standard deviation); with subtracted images, in 21/81 (26%) and 22/161 (14%), and scored 2.5 ± 0.6, respectively (P < 0.001, Sign test). The overall stenosis degree distribution was: mild, 41/161 (25%); moderate, 77/161 (48%); severe, 43/161 (27%). Carotids with moderate stenosis showed vessel wall enhancement with a frequency (17/77, 22%) significantly higher than that observed in carotids with mild stenosis (1/41, 2%) (P = 0.005, Fisher exact test) and higher, even though with borderline significance (P = 0.078, Fisher exact test), than that observed in carotids with severe stenosis (4/43, 9%). Conclusion: Roughly a quarter of patients undergoing carotid MRA showed vessel wall enhancement. Image subtraction improved vessel wall enhancement conspicuity. Vessel wall enhancement seems to be an event relatively independent from the degree of stenosis. Further studies are warranted to define the relation between vessel wall enhancement and histopathology, inflammatory status, and instability.

  4. Improvement in visibility of simulated lung nodules on computed radiography (CR) chest images by use of temporal subtraction technique

    International Nuclear Information System (INIS)

    Oda, Nobuhiro; Fujimoto, Keiji; Murakami, Seiichi; Katsuragawa, Shigehiko; Doi, Kunio; Nakata, Hajime

    1999-01-01

    A temporal subtraction image obtained by subtraction of a previous image from a current one can enhance interval change on chest images. In this study, we compared the visibility of simulated lung nodules on CR images with and without temporal subtraction. Chest phantom images without and with simulated nodules were obtained as previous and current images, respectively, by a CR system. Then, subtraction images were produced with an iterative image warping technique. Twelve simulated nodules were attached on various locations of the chest phantom. The diameter of nodules having a CT number of 47 ranged from 3 mm to 10 mm. Seven radiologists subjectively evaluated the visibility of simulated nodules on CR images with and without temporal subtraction using a three-point rating scale (0: invisible, +1: questionable, +2:visible). The minimum diameter of simulated nodules visible at a frequency greater than 50% was 4 mm on the CR images with temporal subtraction and 6 mm on those without. Our results indicated that the subtraction images clearly improved the visibility of simulated nodules. (author)

  5. The reduction of motion artifacts in digital subtraction angiography by geometrical image transformation

    International Nuclear Information System (INIS)

    Fitzpatrick, J.M.; Pickens, D.R.; Mandava, V.R.; Grefenstette, J.J.

    1988-01-01

    In the diagnosis of arteriosclerosis, radio-opaque dye is injected into the interior of the arteries to make them visible. Because of its increased contrast sensitivity, digital subtraction angiography has the potential for providing diagnostic images of arteries with reduced dye volumes. In the conventional technique, a mask image, acquired before the introduction of the dye, is subtracted from the contrast image, acquired after the dye is introduced, to produce a difference image in which only the dye in the arteries is visible. The usefulness of this technique has been severely limited by the image degradation caused by patient motion during image acquisition. This motion produces artifacts in the difference image that obscure the arteries. One technique for dealing with the problem is to reduce the degradation by means of image registration. The registration is carried out by means of a geometrical transformation of the mask image before subtraction so that it is in registration with the contrast image. This paper describes a technique for determining an optimal transformation. The authors employ a one-to-one elastic mapping and the Jacobian of that mapping to produce a geometrical image transformation. They choose a parameterized class of such mappings and use a heuristic search algorithm to optimize the parameters to minimize the severity of the motion artifacts. To increase the speed of the optimization process they use a statistical image comparison technique that provides a quick approximate evaluation of each image transformation. They present the experimental results of the application of their registration system to mask-contrast pairs, for images acquired from a specially designed phantom, and for clinical images

  6. Metal artifact reduction method using metal streaks image subtraction

    International Nuclear Information System (INIS)

    Pua, Rizza D.; Cho, Seung Ryong

    2014-01-01

    Many studies have been dedicated for metal artifact reduction (MAR); however, the methods are successful to varying degrees depending on situations. Sinogram in-painting, filtering, iterative method are some of the major categories of MAR. Each has its own merits and weaknesses. A combination of these methods or hybrid methods have also been developed to make use of the different benefits of two techniques and minimize the unfavorable results. Our method focuses on the in-paitning approach and a hybrid MAR described by Xia et al. Although in-painting scheme is an effective technique in reducing the primary metal artifacts, a major drawback is the reintroduction of new artifacts that can be caused by an inaccurate interpolation process. Furthermore, combining the segmented metal image to the corrected nonmetal image in the final step of a conventional inpainting approach causes an issue of incorrect metal pixel values. Our proposed method begins with a sinogram in-painting approach and ends with an image-based metal artifact reduction scheme. This work provides a simple, yet effective solution for reducing metal artifacts and acquiring the original metal pixel information. The proposed method demonstrated its effectiveness in a simulation setting. The proposed method showed image quality that is comparable to the standard MAR; however, quantitatively more accurate than the standard MAR

  7. Nonlinear ultrasonic imaging method for closed cracks using subtraction of responses at different external loads.

    Science.gov (United States)

    Ohara, Yoshikazu; Horinouchi, Satoshi; Hashimoto, Makoto; Shintaku, Yohei; Yamanaka, Kazushi

    2011-08-01

    To improve the selectivity of closed cracks for objects other than cracks in ultrasonic imaging, we propose an extension of a novel imaging method, namely, subharmonic phased array for crack evaluation (SPACE) as well as another approach using the subtraction of responses at different external loads. By applying external static or dynamic loads to closed cracks, the contact state in the cracks varies, resulting in an intensity change of responses at cracks. In contrast, objects other than cracks are independent of external load. Therefore, only cracks can be extracted by subtracting responses at different loads. In this study, we performed fundamental experiments on a closed fatigue crack formed in an aluminum alloy compact tension (CT) specimen using the proposed method. We examined the static load dependence of SPACE images and the dynamic load dependence of linear phased array (PA) images by simulating the external loads with a servohydraulic fatigue testing machine. By subtracting the images at different external loads, we show that this method is useful in extracting only the intensity change of responses related to closed cracks, while canceling the responses of objects other than cracks. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Development of a quality assurance protocol for peripheral subtraction imaging applications

    International Nuclear Information System (INIS)

    Walsh, C.; Murphy, D.; O'Hare, N.

    2002-01-01

    Peripheral subtraction scanning is used to trace the blood vessels of upper and lower extremities. In some modern C-arm fluoroscopy systems this function is performed automatically. In this mode the system is programmed to advance and stop in a series of steps taking a mask image at each point. The system then repeats each step after the contrast agent has been injected, and produces a DSA image at each point. Current radiographic quality assurance protocols do not address this feature. This note reviews methods of measuring system vibration while images are being acquired in automated peripheral stepping. The effect on image quality pre- and post-image processing is assessed. Results show that peripheral stepping DSA does not provide the same degree of image quality as static DSA. In examining static test objects, the major cause of the reduction in image quality is misregistration due to vibration of the image intensifier during imaging. (author)

  9. Imaging of the ventricular septal wall and the portal vein by digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Kyoichi; Harashima, Haruhiko; Yamada, Hiromi; Hiraishi, Takahisa; Mikami, Fumio [National Medical Center of Hospital, Tokyo (Japan)

    1983-06-01

    Digital subtraction angiography (DSA) was performed in 2 cases of hypertrophic cardiomyopathy and 2 cases of portal vein disorder. In hypertrophic cardiomyopathy, DSA with the infusion of isopaque 370 at the speed of 5 to 7 ml/sec produced the image of the ventricular septal wall, showing a small ejection fraction. Of portal vein disorders, DSA revealed the portal vein and was helpful in diagnosing tumoral thrombosis of the portal vein in a case of liver carcinoma and portal hypertension.

  10. Ability of subtraction and dynamic MR imaging to detect breast tumors. Comparison with ultrasonography and mammography

    International Nuclear Information System (INIS)

    Terao, Eri; Takeuchi, Hiroaki; Iwamura, Akira; Murakami, Yoshitaka; Harada, Junta; Tada, Shinpei

    1994-01-01

    We evaluated the ability of subtraction and dynamic MR imaging to accurately detect breast tumors. Sixty-five breast carcinomas and 24 fibroadenomas were examined by an SE pulse sequence using a 0.2 Tesla unit. Subtraction MR images were obtained every minute during dynamic study with Gd-DTPA. Almost all breast tumors were seen as very bright masses, and the margin of the mass was clearly demonstrated on subtraction MR images. Breast carcinomas and fibroadenomas showed characteristic time-intensity curves on dynamic study. Time-intensity curves of the early peak type and plateau type were seen in 97% of breast carcinomas, while the gradually increasing type was seen in 92% of fibroadenomas. The detectability of breast carcinoma was 98% by MRI, 98% by ultrasonography, and 87% by mammography. That of fibroadenoma was 95% by MRI, 91% by ultrasonography and 60% by mammography. Sensitivity and specificity for breast carcinoma were 98% and 92% for MRI and 97% and 71% for ultrasonography. For fibroadenoma, they were 96% and 98% for MRI and 89% and 92% for ultrasonography. (author)

  11. Ability of subtraction and dynamic MR imaging to detect breast tumors. Comparison with ultrasonography and mammography

    Energy Technology Data Exchange (ETDEWEB)

    Terao, Eri; Takeuchi, Hiroaki; Iwamura, Akira; Murakami, Yoshitaka; Harada, Junta; Tada, Shinpei (Jikei Univ., Tokyo (Japan). School of Medicine)

    1994-09-01

    We evaluated the ability of subtraction and dynamic MR imaging to accurately detect breast tumors. Sixty-five breast carcinomas and 24 fibroadenomas were examined by an SE pulse sequence using a 0.2 Tesla unit. Subtraction MR images were obtained every minute during dynamic study with Gd-DTPA. Almost all breast tumors were seen as very bright masses, and the margin of the mass was clearly demonstrated on subtraction MR images. Breast carcinomas and fibroadenomas showed characteristic time-intensity curves on dynamic study. Time-intensity curves of the early peak type and plateau type were seen in 97% of breast carcinomas, while the gradually increasing type was seen in 92% of fibroadenomas. The detectability of breast carcinoma was 98% by MRI, 98% by ultrasonography, and 87% by mammography. That of fibroadenoma was 95% by MRI, 91% by ultrasonography and 60% by mammography. Sensitivity and specificity for breast carcinoma were 98% and 92% for MRI and 97% and 71% for ultrasonography. For fibroadenoma, they were 96% and 98% for MRI and 89% and 92% for ultrasonography. (author).

  12. Comparison of the diagnostic accuracy of direct digital radiography system, filtered images, and subtraction radiography

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2013-01-01

    Full Text Available Background: To compare the diagnostic accuracy of three different imaging systems: Direct digital radiography system (DDR-CMOS, four types of filtered images, and a priori and a posteriori registration of digital subtraction radiography (DSR in the diagnosis of proximal defects. Materials and Methods: The teeth were arranged in pairs in 10 blocks of vinyl polysiloxane, and proximal defects were performed with drills of 0.25, 0.5, and 1 mm diameter. Kodak RVG 6100 sensor was used to capture the images. A posteriori DSR registrations were done with Regeemy 0.2.43 and subtraction with Image Tool 3.0. Filtered images were obtained with Kodak Dental Imaging 6.1 software. Images (n = 360 were evaluated by three raters, all experts in dental radiology. Results: Sensitivity and specificity of the area under the receiver operator characteristic (ROC curve (Az were higher for DSR images with all three drills (Az = 0.896, 0.979, and 1.000 for drills 0.25, 0.5, and 1 mm, respectively. The highest values were found for 1-mm drills and the lowest for 0.25-mm drills, with negative filter having the lowest values of all (Az = 0.631. Conclusion: The best method of diagnosis was by using a DSR. The negative filter obtained the worst results. Larger drills showed the highest sensitivity and specificity values of the area under the ROC curve.

  13. The parallel-sequential field subtraction technique for coherent nonlinear ultrasonic imaging

    Science.gov (United States)

    Cheng, Jingwei; Potter, Jack N.; Drinkwater, Bruce W.

    2018-06-01

    Nonlinear imaging techniques have recently emerged which have the potential to detect cracks at a much earlier stage than was previously possible and have sensitivity to partially closed defects. This study explores a coherent imaging technique based on the subtraction of two modes of focusing: parallel, in which the elements are fired together with a delay law and sequential, in which elements are fired independently. In the parallel focusing a high intensity ultrasonic beam is formed in the specimen at the focal point. However, in sequential focusing only low intensity signals from individual elements enter the sample and the full matrix of transmit-receive signals is recorded and post-processed to form an image. Under linear elastic assumptions, both parallel and sequential images are expected to be identical. Here we measure the difference between these images and use this to characterise the nonlinearity of small closed fatigue cracks. In particular we monitor the change in relative phase and amplitude at the fundamental frequencies for each focal point and use this nonlinear coherent imaging metric to form images of the spatial distribution of nonlinearity. The results suggest the subtracted image can suppress linear features (e.g. back wall or large scatters) effectively when instrumentation noise compensation in applied, thereby allowing damage to be detected at an early stage (c. 15% of fatigue life) and reliably quantified in later fatigue life.

  14. Computed tomography lung iodine contrast mapping by image registration and subtraction

    Science.gov (United States)

    Goatman, Keith; Plakas, Costas; Schuijf, Joanne; Beveridge, Erin; Prokop, Mathias

    2014-03-01

    Pulmonary embolism (PE) is a relatively common and potentially life threatening disease, affecting around 600,000 people annually in the United States alone. Prompt treatment using anticoagulants is effective and saves lives, but unnecessary treatment risks life threatening haemorrhage. The specificity of any diagnostic test for PE is therefore as important as its sensitivity. Computed tomography (CT) angiography is routinely used to diagnose PE. However, there are concerns it may over-report the condition. Additional information about the severity of an occlusion can be obtained from an iodine contrast map that represents tissue perfusion. Such maps tend to be derived from dual-energy CT acquisitions. However, they may also be calculated by subtracting pre- and post-contrast CT scans. Indeed, there are technical advantages to such a subtraction approach, including better contrast-to-noise ratio for the same radiation dose, and bone suppression. However, subtraction relies on accurate image registration. This paper presents a framework for the automatic alignment of pre- and post-contrast lung volumes prior to subtraction. The registration accuracy is evaluated for seven subjects for whom pre- and post-contrast helical CT scans were acquired using a Toshiba Aquilion ONE scanner. One hundred corresponding points were annotated on the pre- and post-contrast scans, distributed throughout the lung volume. Surface-to-surface error distances were also calculated from lung segmentations. Prior to registration the mean Euclidean landmark alignment error was 2.57mm (range 1.43-4.34 mm), and following registration the mean error was 0.54mm (range 0.44-0.64 mm). The mean surface error distance was 1.89mm before registration and 0.47mm after registration. There was a commensurate reduction in visual artefacts following registration. In conclusion, a framework for pre- and post-contrast lung registration has been developed that is sufficiently accurate for lung subtraction

  15. K-edge subtraction synchrotron X-ray imaging in bio-medical research.

    Science.gov (United States)

    Thomlinson, W; Elleaume, H; Porra, L; Suortti, P

    2018-05-01

    High contrast in X-ray medical imaging, while maintaining acceptable radiation dose levels to the patient, has long been a goal. One of the most promising methods is that of K-edge subtraction imaging. This technique, first advanced as long ago as 1953 by B. Jacobson, uses the large difference in the absorption coefficient of elements at energies above and below the K-edge. Two images, one taken above the edge and one below the edge, are subtracted leaving, ideally, only the image of the distribution of the target element. This paper reviews the development of the KES techniques and technology as applied to bio-medical imaging from the early low-power tube sources of X-rays to the latest high-power synchrotron sources. Applications to coronary angiography, functional lung imaging and bone growth are highlighted. A vision of possible imaging with new compact sources is presented. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  16. Effective image differencing with convolutional neural networks for real-time transient hunting

    Science.gov (United States)

    Sedaghat, Nima; Mahabal, Ashish

    2018-06-01

    Large sky surveys are increasingly relying on image subtraction pipelines for real-time (and archival) transient detection. In this process one has to contend with varying point-spread function (PSF) and small brightness variations in many sources, as well as artefacts resulting from saturated stars and, in general, matching errors. Very often the differencing is done with a reference image that is deeper than individual images and the attendant difference in noise characteristics can also lead to artefacts. We present here a deep-learning approach to transient detection that encapsulates all the steps of a traditional image-subtraction pipeline - image registration, background subtraction, noise removal, PSF matching and subtraction - in a single real-time convolutional network. Once trained, the method works lightening-fast and, given that it performs multiple steps in one go, the time saved and false positives eliminated for multi-CCD surveys like Zwicky Transient Facility and Large Synoptic Survey Telescope will be immense, as millions of subtractions will be needed per night.

  17. Digital subtraction in gadolinium-enhanced MR imaging of the brain: a method to reduce contrast dosage

    International Nuclear Information System (INIS)

    Chan, J.H.M.; Tsui, E.Y.K.; Chan, C.Y.; Lai, K.F.; Cheung, Y.K.; Wong, K.P.C.; Yuen, M.K.; Chau, L.F.; Fong, D.; Mok, C.K.

    2002-01-01

    The aim of the study was to investigate the feasibility of using digital subtraction in contrast-enhanced MR imaging of the brain to reduce the MR contrast dosage without jeopardizing patient care. Fifty-two patients with intracranial lesions, either intra-axial or extra-axial, detected by computerized tomography were selected for contrast-enhanced MR imaging with half-dose and full-dose of gadopentetate dimeglumine. The half-dose unsubtracted, full-dose unsubtracted, and half-dose subtracted MR images were visually assessed by counting the number of enhancing brain lesions in the images and quantitatively analyzed by computing their lesion contrast-to-background ratios (CBR). The visual conspicuity of the half-dose subtracted MR images was comparable to that of the full-dose unsubtracted MR images (p>0.05), whereas the CBR of the half-dose subtracted images was approximately two to three times higher than that of the full-dose unsubtracted images. The half-dose subtracted T1-weighted spin-echo images might be able to replace the conventional standard-dose T1-weighted spin-echo images in MR imaging of the brain. (orig.)

  18. Tomographic image via background subtraction using an x-ray projection image and a priori computed tomography

    International Nuclear Information System (INIS)

    Zhang Jin; Yi Byongyong; Lasio, Giovanni; Suntharalingam, Mohan; Yu, Cedric

    2009-01-01

    Kilovoltage x-ray projection images (kV images for brevity) are increasingly available in image guided radiotherapy (IGRT) for patient positioning. These images are two-dimensional (2D) projections of a three-dimensional (3D) object along the x-ray beam direction. Projecting a 3D object onto a plane may lead to ambiguities in the identification of anatomical structures and to poor contrast in kV images. Therefore, the use of kV images in IGRT is mainly limited to bony landmark alignments. This work proposes a novel subtraction technique that isolates a slice of interest (SOI) from a kV image with the assistance of a priori information from a previous CT scan. The method separates structural information within a preselected SOI by suppressing contributions to the unprocessed projection from out-of-SOI-plane structures. Up to a five-fold increase in the contrast-to-noise ratios (CNRs) was observed in selected regions of the isolated SOI, when compared to the original unprocessed kV image. The tomographic image via background subtraction (TIBS) technique aims to provide a quick snapshot of the slice of interest with greatly enhanced image contrast over conventional kV x-ray projections for fast and accurate image guidance of radiation therapy. With further refinements, TIBS could, in principle, provide real-time tumor localization using gantry-mounted x-ray imaging systems without the need for implanted markers.

  19. Evaluation of the utility of temporal subtraction images in successive whole-body bone scans: a prospective clinical study

    International Nuclear Information System (INIS)

    Shiraishi, J.; Appelbaum, D.; Pu, Y.; Engelmann, R.; Li Qiang; Doi, K.

    2007-01-01

    We have begun a prospective clinical study for evaluating the clinical utility of temporal subtraction images in successive whole-body bone scans. The computerized temporal subtraction technique has been developed in order to highlight interval changes of abnormal lesions due to skeletal metastases, primary bone tumors, osteomyelitis, and fractures. In our initial preliminary results of the prospective study which was started on November 22, 2006 in our hospital, radiologists reported some interval changes which were not recognized in the initial standard readings, but were obvious when temporal subtraction images were viewed. The usefulness of the temporal subtraction images will be investigated in terms of its clinical utility by the prospective clinical study. (orig.)

  20. Performance of a video-image-subtraction-based patient positioning system

    International Nuclear Information System (INIS)

    Milliken, Barrett D.; Rubin, Steven J.; Hamilton, Russell J.; Johnson, L. Scott; Chen, George T.Y.

    1997-01-01

    Purpose: We have developed and tested an interactive video system that utilizes image subtraction techniques to enable high precision patient repositioning using surface features. We report quantitative measurements of system performance characteristics. Methods and Materials: Video images can provide a high precision, low cost measure of patient position. Image subtraction techniques enable one to incorporate detailed information contained in the image of a carefully verified reference position into real-time images. We have developed a system using video cameras providing orthogonal images of the treatment setup. The images are acquired, processed and viewed using an inexpensive frame grabber and a PC. The subtraction images provide the interactive guidance needed to quickly and accurately place a patient in the same position for each treatment session. We describe the design and implementation of our system, and its quantitative performance, using images both to measure changes in position, and to achieve accurate setup reproducibility. Results: Under clinical conditions (60 cm field of view, 3.6 m object distance), the position of static, high contrast objects could be measured with a resolution of 0.04 mm (rms) in each of two dimensions. The two-dimensional position could be reproduced using the real-time image display with a resolution of 0.15 mm (rms). Two-dimensional measurement resolution of the head of a patient undergoing treatment for head and neck cancer was 0.1 mm (rms), using a lateral view, measuring the variation in position of the nose and the ear over the course of a single radiation treatment. Three-dimensional repositioning accuracy of the head of a healthy volunteer using orthogonal camera views was less than 0.7 mm (systematic error) with an rms variation of 1.2 mm. Setup adjustments based on the video images were typically performed within a few minutes. The higher precision achieved using the system to measure objects than to reposition

  1. Crowded Field Photometry and Moving Object Detection with Optimal Image Subtraction

    Science.gov (United States)

    Lee, Austin A. T.; Scheulen, F.; Sauro, C. M.; McMahon, C. T.; Berry, S. J.; Robinson, C. H.; Buie, M. W.; Little, P.

    2010-05-01

    High precision photometry and moving object detection are essential in the study of Pluto and the Kuiper Belt. In particular, the New Horizons mission would benefit from an accurate and fast method of performing image subtraction to locate faint Kuiper Belt Objects (KBO) among large data sets. The optimal image subtraction (OIS) algorithm was optimized for IDL to decrease execution time by a factor of about 140 from a previous implementation (Miller 2008, PASP, 120, 449). In addition, a powerful image transformation and interpolation routine was written to provide OIS with well-aligned input images using astrometric fit data. The first half of this project is complete including the code optimization and the alignment routine. The second half of the project is focused on using these tools to search a 5 x 10 degree search area to find KBOs for possible targets for the New Horizons mission. We will present examples of how these tools work and along with resulting Pluto photometry and KBO target lists. The optimized OIS and transformation routines are available in Marc Buie's IDL library at http://www.boulder.swri.edu/ buie/idl/ as ois.pro and dewarp.pro. This project was conducted for Harvey Mudd College's Clinic Program with financial support from the NASA Planetary Astronomy Program grant number NNX09AB43G.

  2. PCA-based approach for subtracting thermal background emission in high-contrast imaging data

    Science.gov (United States)

    Hunziker, S.; Quanz, S. P.; Amara, A.; Meyer, M. R.

    2018-03-01

    Aims.Ground-based observations at thermal infrared wavelengths suffer from large background radiation due to the sky, telescope and warm surfaces in the instrument. This significantly limits the sensitivity of ground-based observations at wavelengths longer than 3 μm. The main purpose of this work is to analyse this background emission in infrared high-contrast imaging data as illustrative of the problem, show how it can be modelled and subtracted and demonstrate that it can improve the detection of faint sources, such as exoplanets. Methods: We used principal component analysis (PCA) to model and subtract the thermal background emission in three archival high-contrast angular differential imaging datasets in the M' and L' filter. We used an M' dataset of β Pic to describe in detail how the algorithm works and explain how it can be applied. The results of the background subtraction are compared to the results from a conventional mean background subtraction scheme applied to the same dataset. Finally, both methods for background subtraction are compared by performing complete data reductions. We analysed the results from the M' dataset of HD 100546 only qualitatively. For the M' band dataset of β Pic and the L' band dataset of HD 169142, which was obtained with an angular groove phase mask vortex vector coronagraph, we also calculated and analysed the achieved signal-to-noise ratio (S/N). Results: We show that applying PCA is an effective way to remove spatially and temporarily varying thermal background emission down to close to the background limit. The procedure also proves to be very successful at reconstructing the background that is hidden behind the point spread function. In the complete data reductions, we find at least qualitative improvements for HD 100546 and HD 169142, however, we fail to find a significant increase in S/N of β Pic b. We discuss these findings and argue that in particular datasets with strongly varying observing conditions or

  3. Parametric Imaging Of Digital Subtraction Angiography Studies For Renal Transplant Evaluation

    Science.gov (United States)

    Gallagher, Joe H.; Meaney, Thomas F.; Flechner, Stuart M.; Novick, Andrew C.; Buonocore, Edward

    1981-11-01

    A noninvasive method for diagnosing acute tubular necrosis and rejection would be an important tool for the management of renal transplant patients. From a sequence of digital subtraction angiographic images acquired after an intravenous injection of radiographic contrast material, the parametric images of the maximum contrast, the time when the maximum contrast is reached, and two times the time at which one half of the maximum contrast is reached are computed. The parametric images of the time when the maximum is reached clearly distinguish normal from abnormal renal function. However, it is the parametric image of two times the time when one half of the maximum is reached which provides some assistance in differentiating acute tubular necrosis from rejection.

  4. Anatomic and functional imaging of congenital heart disease with digital subtraction angiography

    International Nuclear Information System (INIS)

    Buonocore, E.; Pavlicek, W.; Modic, M.T.; Meaney, T.F.; O'Donovan, P.B.; Grossman, L.B.; Moodie, D.S.; Yiannikas, J.

    1983-01-01

    Digital subtraction angiography (DSA) of the heart was performed in 54 patients for the evaluation of congenital heart diagnostic images and accurate physiologic shunt data that compared favorably with catheter angiography and nuclear medicine studies. Retrospective analysis of this series of patients indicated that DSA studies contributed sufficient informantion to shorten significantly or modify cardiac catheterization in 85% (79/93) of the defects that were identified. Interatrial septal defects were particularly well diagnosed, with identification occurring in 10 of 10 cases, wheseas intraventricular septal defects were identified in only 6 of 9 patients. Evaluation of postsurgical patients was accurate in 19 of 20 cases

  5. Imaging of the digital arteries: Digital subtraction angiography versus conventional angiography

    International Nuclear Information System (INIS)

    Menanteau, B.P.; Treutenaere, J.M.; Marcus, C.; Ladam, V.; Gausserand, F.

    1986-01-01

    The authors report their experience with the use of digital subtraction angiography (DSA) and conventional angiography of the hand. Of the 95 patients in the study group, 80 underwent conventional angiography and 15 underwent DSA. They analyzed the studies with regard to the type and amount of contrast agent used, the number of radiographs needed, and the diagnostic quality of the images. Conventional angiography often requires general anesthesia, magnification, and pharmaco-angiographic techniques to improve the image-based diagnosis. In comparison with conventional angiography, intraarterial DSA is characterized by improved contrast sensitivity and inferior spatial resolution. However, DSA provides images as acceptable as those of conventional angiography. Smaller catheters can be used, and the examination is performed under local anesthesia. The authors conclude that intraarterial DSA is now the technique of choice for examining patients with chronic ischemia of the hand

  6. Dynamic gadolinium-enhanced subtraction MR imaging - a simple technique for the early diagnosis of Legg-Calve-Perthes disease: preliminary results

    International Nuclear Information System (INIS)

    Sebag, G.; Ducou Le Pointe, H.; Klein, I.; Maiza, D.; Mazda, K.; Bensahel, H.; Hassan, M.

    1997-01-01

    To determine whether the simple technique of dynamic gadolinium-enhanced subtraction MR imaging, which is available on standard MR units, can detect ischemia of the femoral head in children with early Legg-Calve-Perthes disease (LCP). Bone perfusion of eight hips in four patients (mean age 7.5 years) was studied using dynamic gadolinium-enhanced substraction MR imaging at the onset of proven LCP (with initial negative plain films). Enhancement of subtracted images was compared with that on standard MR images and with bone scintigraphy findings. Subtraction MR imaging depicted ischemia as a widespread absence of enhancement and was in good agreement with bone scintigraphy. The subtraction technique improved the sensitivity and the specificity of MR imaging in two children. Furthermore, subtraction MR imaging allowed recognition of the pattern of early reperfusion. Our preliminary results indicate that dynamic gadolinium-enhanced subtraction MRI is a simple and promising means of early recognition of ischemia in LCP. (orig.)

  7. Clinical evaluation of bone-subtraction CT angiography (BSCTA) in head and neck imaging

    International Nuclear Information System (INIS)

    Lell, M.; Anders, K.; Bautz, W.; Klotz, E.; Ditt, H.; Tomandl, B.F.

    2006-01-01

    Fifty-one patients were examined with bone subtraction CT angiography (BSCTA). Data were acquired on 4-and 64-slice spiral CT systems. The post-processing method is based on fully automatic registration of non-enhanced and contrast-enhanced CT data and subsequent selective bone removal. Vascular structures and brain tissue are retained with the original CTA noise level. Image quality and delineation of the pathologic process were assessed and artifacts introduced by the bone removal process recorded. The bone subtraction algorithm worked successfully in all examinations. The processing time was 6 min on average. Image quality was rated excellent in 20 (39%), good in 26 (51%) and acceptable in 5 (10%) patients. Ophthalmic arteries were visible in 12 (24%) patients bilaterally, in 13 (25%) patients unilaterally and in 26 (51%) patients at least at the origin. BSCTA improved visualization of the infraclinoid ICA and the vertebral arteries. The depiction of stenosis of the extracranial ICA and supraclinoid aneurysms was not significantly improved. In patients with suspicion of sinus thrombosis, BSCTA and conventional CTA yielded similar results. To conclude, BSCTA improves the visualization of vessels with close contact to bone and can improve the diagnostic accuracy and therapy planning of infraclinoid aneurysms. (orig.)

  8. An energy-subtraction Compton scatter camera design for in vivo medical imaging of radiopharmaceuticals

    International Nuclear Information System (INIS)

    Rohe, R.C.; Valentine, J.D.

    1996-01-01

    A Compton scatter camera (CSC) design is proposed for imaging radioisotopes used as biotracers. A clinical version may increase sensitivity by a factor of over 100, while maintaining or improving spatial resolution, as compared with existing Anger cameras that use lead collimators. This novel approach is based on using energy subtraction (ΔE = E 0 - E SC , where E 0 , ΔE, and E SC are the energy of the emitted gamma ray, the energy deposited by the initial Compton scatter, and the energy of the Compton scattered photon) to determine the amount of energy deposited in the primary system. The energy subtraction approach allows the requirement of high energy resolution to be placed on a secondary detector system instead of the primary detector system. Requiring primary system high energy resolution has significantly limited previous CSC designs for medical imaging applications. Furthermore, this approach is dependent on optimizing the camera design for data acquisition of gamma rays that undergo only one Compton scatter in a low-Z primary detector system followed by a total absorption of the Compton scattered photon in a high-Z secondary detector system. The proposed approach allows for a more compact primary detector system, a more simplified pulse processing interface, and a much less complicated detector cooling scheme as compared with previous CSC designs. Analytical calculations and Monte Carlo simulation results for some specific detector materials and geometries are presented

  9. A LabVIEW Platform for Preclinical Imaging Using Digital Subtraction Angiography and Micro-CT.

    Science.gov (United States)

    Badea, Cristian T; Hedlund, Laurence W; Johnson, G Allan

    2013-01-01

    CT and digital subtraction angiography (DSA) are ubiquitous in the clinic. Their preclinical equivalents are valuable imaging methods for studying disease models and treatment. We have developed a dual source/detector X-ray imaging system that we have used for both micro-CT and DSA studies in rodents. The control of such a complex imaging system requires substantial software development for which we use the graphical language LabVIEW (National Instruments, Austin, TX, USA). This paper focuses on a LabVIEW platform that we have developed to enable anatomical and functional imaging with micro-CT and DSA. Our LabVIEW applications integrate and control all the elements of our system including a dual source/detector X-ray system, a mechanical ventilator, a physiological monitor, and a power microinjector for the vascular delivery of X-ray contrast agents. Various applications allow cardiac- and respiratory-gated acquisitions for both DSA and micro-CT studies. Our results illustrate the application of DSA for cardiopulmonary studies and vascular imaging of the liver and coronary arteries. We also show how DSA can be used for functional imaging of the kidney. Finally, the power of 4D micro-CT imaging using both prospective and retrospective gating is shown for cardiac imaging.

  10. Usefulness of computerized method for lung nodule detection on digital chest radiographs using similar subtraction images from different patients

    International Nuclear Information System (INIS)

    Aoki, Takatoshi; Oda, Nobuhiro; Yamashita, Yoshiko; Yamamoto, Keiji; Korogi, Yukunori

    2012-01-01

    Purpose: The purpose of this study is to evaluate the usefulness of a novel computerized method to select automatically the similar chest radiograph for image subtraction in the patients who have no previous chest radiographs and to assist the radiologists’ interpretation by presenting the “similar subtraction image” from different patients. Materials and methods: Institutional review board approval was obtained, and the requirement for informed patient consent was waived. A large database of approximately 15,000 normal chest radiographs was used for searching similar images of different patients. One hundred images of candidates were selected according to two clinical parameters and similarity of the lung field in the target image. We used the correlation value of chest region in the 100 images for searching the most similar image. The similar subtraction images were obtained by subtracting the similar image selected from the target image. Thirty cases with lung nodules and 30 cases without lung nodules were used for an observer performance test. Four attending radiologists and four radiology residents participated in this observer performance test. Results: The AUC for all radiologists increased significantly from 0.925 to 0.974 with the CAD (P = .004). When the computer output images were available, the average AUC for the residents was more improved (0.960 vs. 0.890) than for the attending radiologists (0.987 vs. 0.960). Conclusion: The novel computerized method for lung nodule detection using similar subtraction images from different patients would be useful to detect lung nodules on digital chest radiographs, especially for less experienced readers.

  11. Averaged subtracted polarization imaging for endoscopic diagnostics of surface microstructures on translucent mucosae

    Science.gov (United States)

    Kanamori, Katsuhiro

    2016-07-01

    An endoscopic image processing technique for enhancing the appearance of microstructures on translucent mucosae is described. This technique employs two pairs of co- and cross-polarization images under two different linearly polarized lights, from which the averaged subtracted polarization image (AVSPI) is calculated. Experiments were then conducted using an acrylic phantom and excised porcine stomach tissue using a manual experimental setup with ring-type lighting, two rotating polarizers, and a color camera; better results were achieved with the proposed method than with conventional color intensity image processing. An objective evaluation method that uses texture analysis was developed and used to evaluate the enhanced microstructure images. This paper introduces two types of online, rigid-type, polarimetric endoscopic implementations using a polarized ring-shaped LED and a polarimetric camera. The first type uses a beam-splitter-type color polarimetric camera, and the second uses a single-chip monochrome polarimetric camera. Microstructures on the mucosa surface were enhanced robustly with these online endoscopes regardless of the difference in the extinction ratio of each device. These results show that polarimetric endoscopy using AVSPI is both effective and practical for hardware implementation.

  12. Optimum allocation of imaging time and minimum detectable activity in dual isotope blood pool subtraction indium-111 platelet imaging

    International Nuclear Information System (INIS)

    Machac, J.; Horowitz, S.F.; Goldsmith, S.J.; Fuster, V.

    1984-01-01

    Indium-111 labeled platelet imaging is a tool for detection of thrombus formation in vascular spaces. Dual isotope blood pool subtraction may help differentiate focal platelet accumulation from blood pool activity. This study used a computer model to calculate the minimum excess-to-blood pool platelet ratio (EX/BP) and the optimum dual isotope imaging times under varied conditions of lesion size. The model simulated usual human imaging doses of 500 μCi of In-111 platelets and 5mCi of Tc-99m labeled RBCs giving a reference cardiac blood pool region (100cc) of 10000 cpm for Tc-99m and 500 cpm for In-111. The total imaging time was fixed at 20 minutes, while the two isotope imaging times (TIn/TTc) were varied, as were the simulated lesion size (cc) and EX/BP. The relative error of the excess counts was calculated using propagation of error theory. At the critical level of detection, where the excess lesion counts equal 3 times the standard deviation, the optimum TIn/TTc and minimum Ex/BP were determined for each lesion size. For the smallest lesion size (0.1cc), the minimum detectable EX/BP ratio was 1.6, with the best TIn/TTC ratio of 18/2 minutes, and for large lesions, an EX/BP of 0.1, with a TIn/TTc of 16/4. This model provides an estimate of the sensitivity and optimizes imaging times in dual isotope subtraction platelet imaging. The model is adaptable to varying isotope doses, total imaging times and lesion size. This information will be helpful in future in- vivo imaging studies of intravascular thrombi in humans

  13. Three dimensional mapping of strontium in bone by dual energy K-edge subtraction imaging

    International Nuclear Information System (INIS)

    Cooper, D M L; Chapman, L D; Carter, Y; Zhouping, W; Wu, Y; Panahifar, A; Duke, M J M; Doschak, M; Britz, H M; Bewer, B

    2012-01-01

    The bones of many terrestrial vertebrates, including humans, are continually altered through an internal process of turnover known as remodeling. This process plays a central role in bone adaptation and disease. The uptake of fluorescent tetracyclines within bone mineral is widely exploited as a means of tracking new tissue formation. While investigation of bone microarchitecture has undergone a dimensional shift from 2D to 3D in recent years, we lack a 3D equivalent to fluorescent labeling. In the current study we demonstrate the ability of synchrotron radiation dual energy K-edge subtraction (KES) imaging to map the 3D distribution of elemental strontium within rat vertebral samples. This approach has great potential for ex vivo analysis of preclinical models and human tissue samples. KES also represents a powerful tool for investigating the pharmokinetics of strontium-based drugs recently approved in many countries around the globe for the treatment of osteoporosis. (paper)

  14. Comparisons of images simultaneously documented by digital subtraction coronary arteriography and cine coronary arteriography

    International Nuclear Information System (INIS)

    Kimura, Koji; Takamiya, Makoto; Yamamoto, Kazuo; Ohta, Mitsushige; Naito, Hiroaki

    1988-01-01

    Using an angiography apparatus capable of simultaneously processing digital subtraction angiograms and cine angiograms, the diagnostic capabilities of both methods for the coronary arteries (DSCAG and Cine-CAG) were compared. Twenty stenotic lesions of the coronary arteries of 11 patients were evaluated using both modalities. The severity of stenosis using DSCAG with a 512x512x8 bit matrix was semiautomatically measured on the cathode ray tube (CRT) based on enlarged images on the screen of a Vanguard cine projector which were of the same size as those of or 10 times larger than images of Cine-CAG. The negative and positive hard copies of DSCAG images were also compared with those of Cine-CAG. The correlation coefficients of the severity of stenosis by DSCAG and Cine-CAG were as follows: (1) the same size DSCAG images on CRT to Cine-CAG, 0.95, (2) 10 times enlarged DSCAG images on CRT to Cine-CAG, 0.96, and (3) the same size DSCAG images on negative and positive hard copies to Cine-CAG, 0.97. The semiautomatically measured values of 10 times enlarged DSCAG images on CRT and the manually measured values of the same size negative and positive DSCAG images in hard copy closely correlated with the values measured using Cine-CAG. When the liver was superimposed in the long-axis projection, the diagnostic capabilities of DSCAG and Cine-CAG were compared. The materials included 10 left coronary arteriograms and 11 right coronary arteriograms. Diagnostically, DSCAG was more useful than Cine-CAG in the long-axis projection. (author)

  15. [Quantitative image of bone mineral content--dual energy subtraction in a single exposure].

    Science.gov (United States)

    Katoh, T

    1990-09-25

    A dual energy subtraction system was constructed on an experimental basis for the quantitative image of bone mineral content. The system consists of a radiography system and an image processor. Two radiograms were taken with dual x-ray energy in a single exposure using an x-ray beam dichromized by a tin filter. In this system, a film cassette was used where a low speed film-screen system, a copper filter and a high speed film-screen system were layered on top of each other. The images were read by a microdensitometer and processed by a personal computer. The image processing included the corrections of the film characteristics and heterogeneity in the x-ray field, and the dual energy subtraction in which the effect of the high energy component of the dichromized beam on the tube side image was corrected. In order to determine the accuracy of the system, experiments using wedge phantoms made of mixtures of epoxy resin and bone mineral-equivalent materials in various fractions were performed for various tube potentials and film processing conditions. The results indicated that the relative precision of the system was within +/- 4% and that the propagation of the film noise was within +/- 11 mg/cm2 for the 0.2 mm pixels. The results also indicated that the system response was independent of the tube potential and the film processing condition. The bone mineral weight in each phalanx of the freshly dissected hand of a rhesus monkey was measured by this system and compared with the ash weight. The results showed an error of +/- 10%, slightly larger than that of phantom experiments, which is probably due to the effect of fat and the variation of focus-object distance. The air kerma in free air at the object was approximately 0.5 mGy for one exposure. The results indicate that this system is applicable to clinical use and provides useful information for evaluating a time-course of localized bone disease.

  16. A computer-aided diagnosis system to detect pathologies in temporal subtraction images of chest radiographs

    Science.gov (United States)

    Looper, Jared; Harrison, Melanie; Armato, Samuel G.

    2016-03-01

    Radiologists often compare sequential radiographs to identify areas of pathologic change; however, this process is prone to error, as human anatomy can obscure the regions of change, causing the radiologists to overlook pathology. Temporal subtraction (TS) images can provide enhanced visualization of regions of change in sequential radiographs and allow radiologists to better detect areas of change in radiographs. Not all areas of change shown in TS images, however, are actual pathology. The purpose of this study was to create a computer-aided diagnostic (CAD) system that identifies which regions of change are caused by pathology and which are caused by misregistration of the radiographs used to create the TS image. The dataset used in this study contained 120 images with 74 pathologic regions on 54 images outlined by an experienced radiologist. High and low ("light" and "dark") gray-level candidate regions were extracted from the images using gray-level thresholding. Then, sampling techniques were used to address the class imbalance problem between "true" and "false" candidate regions. Next, the datasets of light candidate regions, dark candidate regions, and the combined set of light and dark candidate regions were used as training and testing data for classifiers by using five-fold cross validation. Of the classifiers tested (support vector machines, discriminant analyses, logistic regression, and k-nearest neighbors), the support vector machine on the combined candidates using synthetic minority oversampling technique (SMOTE) performed best with an area under the receiver operating characteristic curve value of 0.85, a sensitivity of 85%, and a specificity of 84%.

  17. Analysis on imaging features of mammography in computer radiography and investigation on gray scale transform and energy subtraction

    International Nuclear Information System (INIS)

    Feng Shuli

    2003-01-01

    In this dissertation, a novel transform method based on human visual response features for gray scale mammographic imaging in computer radiography (CR) is presented. The parameters for imaging quality on CR imaging for mammography were investigated experimentally. In addition, methods for image energy subtraction and a novel method of image registration for mammography of CR imaging are presented. Because the images are viewed and investigated by humans, the method of displaying differences in gray scale images is more convenient if the gray scale differences are displayed in a manner commensurate with human visual response principles. Through transformation of image gray scale with this method, the contrast of the image will be enhanced and the capability for humans to extract the useful information from the image will be increased. Tumors and microcalcifications are displayed in a form for humans to view more simply after transforming the image. The method is theoretically and experimentally investigated. Through measurement of the parameters of a geometrically blurred image, MTF, DQE, and ROC on CR imaging, and also comparison with the imaging quality of screen-film systems, the results indicate that CR imaging qualities in DQE and ROC are better than those of screen-film systems. In geometric blur of the image and MTF, the differences in image quality between CR and the screen-film system are very small. The results suggest that the CR system can replace the screen-film system for mammography imaging. In addition, the results show that the optimal imaging energy for CR mammography is about 24 kV. This condition indicates that the imaging energy of the CR system is lower than that of the screen-film system and, therefore, the x-ray dose to the patient for mammography with the CR system is lower than that with the screen-film system. Based on the difference of penetrability of x ray with different wavelength, and the fact that the part of the x-ray beam will pass

  18. Subtractive Leadership

    Science.gov (United States)

    Larwin, K. H.; Thomas, Eugene M.; Larwin, David A.

    2015-01-01

    This paper introduces a new term and concept to the leadership discourse: Subtractive Leadership. As an extension of the distributive leadership model, the notion of subtractive leadership refers to a leadership style that detracts from organizational culture and productivity. Subtractive leadership fails to embrace and balance the characteristics…

  19. Preoperative imaging in primary hyperparathyroidism. Role of thallium-technetium subtraction scintigraphy

    International Nuclear Information System (INIS)

    Foster, G.S.; Bekerman, C.; Blend, M.J.; Byrom, E.; Pinsky, S.M.

    1989-01-01

    Primary hyperparathyroidism, although often silent clinically, may lead to significant morbidity if it remains untreated. In more than 95% of all cases the cause is a parathyroid adenoma or glandular hyperplasia. Regression of disease follows successful surgical excision of the abnormal parathyroid gland. Recurrent or persistent hyperparathyroidism is most commonly caused by solitary adenomas, which may have an ectopic location. Preoperative localization of lesions may improve postoperative cure rates and decrease morbidity. Thallium T1 201 chloride-technetium Tc 99m pertechnetate subtraction scintigraphy was performed on 15 patients with primary hyperparathyroidism. The sensitivity and specificity for detection of abnormal glands were 90% and 95%, respectively. False-positive or false-negative results were minimize by strict adherence to a protocol and by the use of well-defined diagnostic criteria. Because of the superior sensitivity and specificity, this modality should be the primary imaging method of choice for preoperative evaluation of primary hyperparathyroidism. The relative role of other imaging modalities is also discussed. 31 references

  20. Brain MR post-gadolinium contrast in multiple sclerosis: the role of magnetization transfer and image subtraction in detecting more enhancing lesions

    Energy Technology Data Exchange (ETDEWEB)

    Gavra, M.M.; Gouliamos, A.D.; Vlahos, L.J. [Department of Radiology, ' ' Aretaieion' ' Hospital,University of Athens Medical School, Athens (Greece); Voumvourakis, C.; Sfagos, C. [Department of Neurology, ' ' Eginiteion' ' Hospital, University of Athens Medical School, Athens (Greece)

    2004-03-01

    Our purpose was to evaluate the role of magnetization transfer and image subtraction in detecting more enhancing lesions in brain MR imaging of patients with multiple sclerosis (MS). Thirty-one MS patients underwent MR imaging of the brain with T1-weighted spin echo sequences without and with magnetization transfer (MT) using a 1.5 T imager. Both sequences were acquired before and after intravenous injection of a paramagnetic contrast agent. Subtraction images in T1-weighted sequences were obtained by subtracting the pre-contrast images from the post-contrast ones. A significant difference was found between the numbers of enhanced areas in post-gadolinium T1-weighted images without and with MT (p=0.020). The post-gadolinium T1-weighted images with MT allowed the detection of an increased (13) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. A significant difference was also found between the numbers of enhanced areas in post-gadolinium T1-weighted images without MT and subtraction images without MT (p=0.020). The subtraction images without MT allowed the detection of an increased (10) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. Magnetization transfer contrast and subtraction techniques appear to be the simplest and least time-consuming applications to improve the conspicuity and detection of contrast-enhancing lesions in patients with MS. (orig.)

  1. Brain MR post-gadolinium contrast in multiple sclerosis: the role of magnetization transfer and image subtraction in detecting more enhancing lesions

    International Nuclear Information System (INIS)

    Gavra, M.M.; Gouliamos, A.D.; Vlahos, L.J.; Voumvourakis, C.; Sfagos, C.

    2004-01-01

    Our purpose was to evaluate the role of magnetization transfer and image subtraction in detecting more enhancing lesions in brain MR imaging of patients with multiple sclerosis (MS). Thirty-one MS patients underwent MR imaging of the brain with T1-weighted spin echo sequences without and with magnetization transfer (MT) using a 1.5 T imager. Both sequences were acquired before and after intravenous injection of a paramagnetic contrast agent. Subtraction images in T1-weighted sequences were obtained by subtracting the pre-contrast images from the post-contrast ones. A significant difference was found between the numbers of enhanced areas in post-gadolinium T1-weighted images without and with MT (p=0.020). The post-gadolinium T1-weighted images with MT allowed the detection of an increased (13) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. A significant difference was also found between the numbers of enhanced areas in post-gadolinium T1-weighted images without MT and subtraction images without MT (p=0.020). The subtraction images without MT allowed the detection of an increased (10) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. Magnetization transfer contrast and subtraction techniques appear to be the simplest and least time-consuming applications to improve the conspicuity and detection of contrast-enhancing lesions in patients with MS. (orig.)

  2. Optical image encryption based on real-valued coding and subtracting with the help of QR code

    Science.gov (United States)

    Deng, Xiaopeng

    2015-08-01

    A novel optical image encryption based on real-valued coding and subtracting is proposed with the help of quick response (QR) code. In the encryption process, the original image to be encoded is firstly transformed into the corresponding QR code, and then the corresponding QR code is encoded into two phase-only masks (POMs) by using basic vector operations. Finally, the absolute values of the real or imaginary parts of the two POMs are chosen as the ciphertexts. In decryption process, the QR code can be approximately restored by recording the intensity of the subtraction between the ciphertexts, and hence the original image can be retrieved without any quality loss by scanning the restored QR code with a smartphone. Simulation results and actual smartphone collected results show that the method is feasible and has strong tolerance to noise, phase difference and ratio between intensities of the two decryption light beams.

  3. Comparison of 3D magnetic resonance imaging and digital subtraction angiography for intracranial artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Eun; Jung, Seung Chai; Kim, Ho Sung; Choi, Choong-Gon; Kim, Sang Joon; Lee, Deok Hee [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Lee, Sang Hun; Kwon, Sun U.; Kang, Dong-Wha; Kim, Jong S. [University of Ulsan College of Medicine, Department of Neurology, Ulsan (Korea, Republic of); Jeon, Ji Young [Gachon University, Department of Radiology, Gil Medical Center, Incheon (Korea, Republic of); Lee, Ji Ye [Soonchunhyang University Bucheon Hospital, Department of Radiology, Bucheon (Korea, Republic of); Kim, Seon-Ok [University of Ulsan College of Medicine, Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, Seoul (Korea, Republic of)

    2017-11-15

    To compare three-dimensional high-resolution magnetic resonance imaging (3D HR-MRI) and digital subtraction angiography (DSA) for diagnosing and evaluating stenosis in the entire circle of Willis. The study included 516 intracranial arteries from 43 patients with intracranial artery stenosis (ICAS) who underwent both 3D HR-MRI and DSA within 1 month. Two readers independently diagnosed atherosclerosis, dissection, moyamoya disease and vasculitis, rated their diagnostic confidence for each vessel and measured the luminal diameters. Reference standard was made from clinico-radiologic diagnosis. Diagnostic accuracy, diagnostic confidence, the degree of stenosis and luminal diameter were assessed and compared between both modalities. For atherosclerosis, 3D HR-MRI showed better diagnostic accuracy (P =.03-.003), sensitivity (P =.006-.01) and positive predictive value (P ≤.001-.006) compared to DSA. Overall, the readers were more confident of their diagnosis of ICAS when using 3D HR-MRI (reader 1, P ≤.001-.007; reader 2, P ≤.001-.015). 3D HR-MRI showed similar degree of stenosis (P >.05) and higher luminal diameter (P <.05) compared to DSA. 3D HR-MRI might be useful to evaluate atherosclerosis, with better diagnostic confidence and comparable stenosis measurement compared to DSA in the entire circle of Willis. (orig.)

  4. Spectral K-edge subtraction imaging of experimental non-radioactive barium uptake in bone.

    Science.gov (United States)

    Panahifar, Arash; Samadi, Nazanin; Swanston, Treena M; Chapman, L Dean; Cooper, David M L

    2016-12-01

    To evaluate the feasibility of using non-radioactive barium as a bone tracer for detection with synchrotron spectral K-edge subtraction (SKES) technique. Male rats of 1-month old (i.e., developing skeleton) and 8-month old (i.e., skeletally mature) were orally dosed with low dose of barium chloride (33mg/kg/day Ba 2+ ) for 4weeks. The fore and hind limbs were dissected for imaging in projection and computed tomography modes at 100μm and 52μm pixel sizes. The SKES method utilizes a single bent Laue monochromator to prepare a 550eV energy spectrum to encompass the K-edge of barium (37.441keV), for collecting both 'above' and 'below' the K-edge data sets in a single scan. The SKES has a very good focal size, thus limits the 'crossover' and motion artifacts. In juvenile rats, barium was mostly incorporated in the areas of high bone turnover such as at the growth plate and the trabecular surfaces, but also in the cortical bone as the animals were growing at the time of tracer administration. However, the adults incorporated approximately half the concentration and mainly in the areas where bone remodeling was predominant and occasionally in the periosteal and endosteal layers of the diaphyseal cortical bone. The presented methodology is simple to implement and provides both structural and functional information, after labeling with barium, on bone micro-architecture and thus has great potential for in vivo imaging of pre-clinical animal models of musculoskeletal diseases to better understand their mechanisms and to evaluate the efficacy of pharmaceuticals. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. In vivo optical imaging of amblyopia: Digital subtraction autofluorescence and split-spectrum amplitude-decorrelation angiography.

    Science.gov (United States)

    Guo, Lei; Tao, Jun; Xia, Fan; Yang, Zhi; Ma, Xiaoli; Hua, Rui

    2016-09-01

    Amblyopia is a visual impairment that is attributed to either abnormal binocular interactions or visual deprivation. The retina and choroids have been shown to be involved in the development of amblyopia. The purpose of this study was to investigate the retinal and choroidal microstructural abnormalities of amblyopia using digital subtraction autofluorescence and split-spectrum amplitude-decorrelation angiography (SSADA) approaches. This prospective study included 44 eyes of 22 patients with unilateral amblyopia. All patients who received indirect ophthalmoscopy, combined depth imaging spectral domain optical coherence tomography (OCT), SSADA-OCT, and macular blue light (BL-) and near-infrared (NIR-) autofluorescences underwent pupil dilation. The subfoveal choroidal thickness (SFCT) was measured. BL- and NIR-autofluorescences were determined for all patients and used to generate subtraction images with ImageJ software. The superficial, deep layers of the retina, and inner choroid layer were required for SSADA-OCT. For the normal eyes, a regularly increasing signal was observed in the central macula based on the subtraction images. In contrast, a decreased signal for the central patch or a reduced peak was detected in 16 of 22 amblyopic eyes (72.7%). The mean SFCT of the amblyopic eyes was greater than that of the fellow normal eyes (399.25 ± 4.944 µm vs. 280.58 ± 6.491 µm, respectively, P autofluorescence. The mechanistic relationship of a thicker choroid and choroidal capillary atrophy with amblyopia remains to be described. The digital subtraction image confirmed the changes in the microstructure of the amblyopic retina as a supplementary approach to detect the progression of amblyopia. Lasers Surg. Med. 48:660-667, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  6. Dynamic subtraction magnetic resonance venography: a new real time imaging technique for the detection of dural sinus thrombosis

    International Nuclear Information System (INIS)

    Mandel, C.; Birchall, D.; Connolly, D.; English, P.

    2002-01-01

    Full text: Requests for imaging suspected dural sinus thrombosis are increasing. Conventional magnetic imaging (MRI) and magnetic resonance venography (MRV) are often used to detect venous sinus thrombosis, but these techniques are prone to technical problems. Catheter angiography is sometimes required as the final arbiter in the evaluation of the dural venous sinuses. Recent technical developments in MR scanning have allowed the development of dynamic subtraction MRA. This technique is beginning to be applied to the assessment of intracranial vascular malformations. We have recently applied the technique to the imaging of the dural venous sinuses, and describe our early experience with the technique. Imaging was performed on a Philips Intera 1.5T scanner with gradient strength 33 mT and slew rate 130 T/m/sec. T1-weighed fast field echo imaging was performed (flip angle 400, TR 1.5 msec) during bolus injection of gadolinium (5ml gadolinium followed by a 10 ml saline chaser) at 5-6 ml/sec using a MRI-compatible pump injector. Slice thickness depended on the plane of acquisition, but was between 100- 150 mm. Images were acquired in three orthogonal projections in each case, using 3 separate contrast injections. Mask images were obtained before the arrival of contrast, and subtracted reconstructed images were obtained in real time, providing a dynamic display of the intracranial circulation including the dural venous sinuses. Frame rate was 1 frame per 0.8 seconds. We will present dynamic MR angiographic images in a number of patients. Normal appearances and those seen in venous sinus thrombosis will be presented in the video display. Dynamic MR venography is a new technique for the imaging of dural venous sinuses. In our practice, it has proved a valuable adjunct for the imaging of patients with dural venous sinus thrombosis. Copyright (2002) Blackwell Science Pty Ltd

  7. Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging.

    Directory of Open Access Journals (Sweden)

    Mark A Lum

    Full Text Available To evaluate the ability of IA MR perfusion to characterize meningioma blood supply.Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA and intravenous (IV T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA dural, internal carotid artery (ICA dural, or pial. MR perfusion data regions of interest (ROIs were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM, relative cerebral blood flow (rCBF, relative cerebral blood volume (rCBV, and mean transit time (MTT. Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling.18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11, ICA dural (n = 4, or pial (n = 3. FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion.

  8. Three-dimensional image reconstruction using rotational digital subtraction technique: the initial experience of the clinical application

    International Nuclear Information System (INIS)

    Ouyang Zhongnan; Tang Jun; He Jianjun; Lu Xiaohe; Xun Yanping

    2002-01-01

    Objective: To evaluate the benefit of three-dimensional (3D) reconstruction images with rotational digital subtraction technique for the clinical applications. Methods: Conventional two-dimensional digital substraction angiography (2D DSA) was obtained on A-P and lateral view. Three-dimensional digital subtraction angiography (3D DSA) images were obtained by reconstruction of a rotational acquisition on a C-arm (LCV +, GE Medical Systems) spinning at 40 degrees per second. 53 cases of cerebral angiographies were performed (32 men and 21 women; the age ranged from 19 to 72 years, mean 46.3 years). Results: In this series of 53 cases of cerebral angiographies, 5 cases of arteriovenous malformation were all correctly diagnosed by 3D DSA and 2D DSA. Seven cases were misdiagnosed as intracranial aneurysms at conventional 2D DSA but confirmed to be kinking of the vessel by 3D DSA. 41 cases were confirmed to be intracranial aneurysms. Of the 41 cases, 5 cases were diagnosed as normal at 2D DSA but confirmed to be intracranial aneurysms at 3D DSA. The total consistency rate of 3D DSA and 2D DSA for the diagnosis of intracranial aneurysm is 77.4% (41/53). The consistent test shows that there was consistency between the two modalities (chi-square test, χ 2 = 5.267, P < 0.05). 29 cases were treated with endovascular coil embolization. Among them only 3 cases of the aneurysm's neck could be best visualized by 2D DSA but 29 cases by 3D DSA. Conclusion: 3D reconstruction images with rotational digital subtraction technique is a useful tool to study the vascular diseases using less contrast agent and a lower radiation dose and shortening the examination process. It is replenishment for conventional 2D DSA. This technique enables better diagnosis for intracranial vascular lesion and visualization of complex vascular relationships and structures. It is valuable for surgical planning and interventional procedure

  9. Nonlinear Geometric Warping of the Mask Image: A New Method for Reducing Misregistration Artifacts in Digital Subtraction Angiography

    International Nuclear Information System (INIS)

    Hayashi, Nobushige; Sakai, Toyohiko; Kitagawa, Manabu; Inagaki, Rika; Sadato, Norihiro; Ishii, Yasushi; Nishimoto, Yasuhiro; Tanaka, Masato; Fukushima, Tetsuya; Komuro, Hiroyuki; Ogura, Hisakazu; Kobayashi, Hidenori; Kubota, Toshihiko

    1998-01-01

    Purpose: Misregistration artifact is the major cause of image degradation in digital subtraction angiography (DSA). The purpose of this study was to evaluate the efficacy of a newly developed nonlinear geometric warping method to reduce misregistration artifact in DSA. Methods: The processing of the images was carried out on a workstation with a fully automatic computerized program. After making differential images with a lapracian filter, 49 regions of interest (ROIs) were set in the image to be processed. Each ROI of the live image scanned the corresponding ROI of the mask image searching for the best position to match itself. Each pixel of the mask image was shifted individually following the data calculated from the shifts of the ROIs. Five radiologists compared the images produced by the conventional parallel shift technique and those processed with this new method in 16 series of cerebral DSA. Results: In 14 of 16 series (88%), more radiologists judged the images processed with the new method to be better in quality. Small arteries near the skull base and veins of low density were clearly visualized in the images processed by the new method. Conclusion: This newly proposed method could be a simple and practical way to automatically reduce misregistration artifacts in DSA

  10. Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Baissalov, R.; Sandison, G.A.; Rewcastle, J.C. [Department of Medical Physics, Tom Baker Cancer Center, Calgary, Canada, T2N 4N2 2 Department of Physics and Astronomy, University of Calgary, Calgary T2N 2N4 (Canada); Donnelly, B.J. [Department of Surgery, Tom Baker Cancer Center, Calgary, Canada, T2N 4N2 4 Department of Surgery, Foothills Hospital, Calgary T2N 2T7 (Canada); Saliken, J.C. [Department of Surgery, Tom Baker Cancer Center, Calgary T2N 4N2 (Canada); Department of Diagnostic Imaging, Foothills Hospital, Calgary T2N 2T7 (Canada); McKinnon, J.G. [Department of Surgery, Foothills Hospital, Calgary T2N 2T7 (Canada); Muldrew, K. [Department of Surgery, Faculty of Medicine, University of Calgary, Calgary T2N 2T7 (Canada)

    2000-05-01

    Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey-scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high-density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent. (author)

  11. Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

    International Nuclear Information System (INIS)

    Baissalov, R.; Sandison, G.A.; Rewcastle, J.C.; Donnelly, B.J.; Saliken, J.C.; McKinnon, J.G.; Muldrew, K.

    2000-01-01

    Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey-scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high-density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent. (author)

  12. Visualisation of bony and vascular structures via digital subtraction images upon the amount of anatomic background

    International Nuclear Information System (INIS)

    Hinz, A.; Scholz, A.; Zwicker, C.

    1992-01-01

    We examined the loss of contrast leaving a part of the anatomic background in digital subtraction angiography by visual analysis and densitometry. We observed a greater loss of the quality at the representation of the bone below than above an amount of anatomic background of 60%. The loss of quality at the representation of the vessels decreases more above than below an anatomical background of 45%. We think that, depending on the clinical problem, an anatomical background between 15 and 30% should be left. (orig.) [de

  13. The value of subtraction MRI in detection of amyloid-related imaging abnormalities with oedema or effusion in Alzheimer's patients: An interobserver study.

    Science.gov (United States)

    Martens, Roland M; Bechten, Arianne; Ingala, Silvia; van Schijndel, Ronald A; Machado, Vania B; de Jong, Marcus C; Sanchez, Esther; Purcell, Derk; Arrighi, Michael H; Brashear, Robert H; Wattjes, Mike P; Barkhof, Frederik

    2018-03-01

    Immunotherapeutic treatments targeting amyloid-β plaques in Alzheimer's disease (AD) are associated with the presence of amyloid-related imaging abnormalities with oedema or effusion (ARIA-E), whose detection and classification is crucial to evaluate subjects enrolled in clinical trials. To investigate the applicability of subtraction MRI in the ARIA-E detection using an established ARIA-E-rating scale. We included 75 AD patients receiving bapineuzumab treatment, including 29 ARIA-E cases. Five neuroradiologists rated their brain MRI-scans with and without subtraction images. The accuracy of evaluating the presence of ARIA-E, intraclass correlation coefficient (ICC) and specific agreement was calculated. Subtraction resulted in higher sensitivity (0.966) and lower specificity (0.970) than native images (0.959, 0.991, respectively). Individual rater detection was excellent. ICC scores ranged from excellent to good, except for gyral swelling (moderate). Excellent negative and good positive specific agreement among all ARIA-E imaging features was reported in both groups. Combining sulcal hyperintensity and gyral swelling significantly increased positive agreement for subtraction images. Subtraction MRI has potential as a visual aid increasing the sensitivity of ARIA-E assessment. However, in order to improve its usefulness isotropic acquisition and enhanced training are required. The ARIA-E rating scale may benefit from combining sulcal hyperintensity and swelling. • Subtraction technique can improve detection amyloid-related imaging-abnormalities with edema/effusion in Alzheimer's patients. • The value of ARIA-E detection, classification and monitoring using subtraction was assessed. • Validation of an established ARIA-E rating scale, recommendations for improvement are reported. • Complementary statistical methods were employed to measure accuracy, inter-rater-reliability and specific agreement.

  14. M-BAND IMAGING OF THE HR 8799 PLANETARY SYSTEM USING AN INNOVATIVE LOCI-BASED BACKGROUND SUBTRACTION TECHNIQUE

    International Nuclear Information System (INIS)

    Galicher, Raphael; Marois, Christian; Macintosh, Bruce; Konopacky, Quinn; Barman, Travis

    2011-01-01

    Multi-wavelength observations/spectroscopy of exoplanetary atmospheres are the basis of the emerging exciting field of comparative exoplanetology. The HR 8799 planetary system is an ideal laboratory to study our current knowledge gap between massive field brown dwarfs and the cold 5 Gyr old solar system planets. The HR 8799 planets have so far been imaged at J- to L-band, with only upper limits available at M-band. We present here deep high-contrast Keck II adaptive optics M-band observations that show the imaging detection of three of the four currently known HR 8799 planets. Such detections were made possible due to the development of an innovative LOCI-based background subtraction scheme that is three times more efficient than a classical median background subtraction for Keck II AO data, representing a gain in telescope time of up to a factor of nine. These M-band detections extend the broadband photometric coverage out to ∼5 μm and provide access to the strong CO fundamental absorption band at 4.5 μm. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. We also confirm that the best atmospheric fits are consistent with low surface gravity, dusty, and non-equilibrium CO/CH 4 chemistry models.

  15. Small lung cancers: improved detection by use of bone suppression imaging--comparison with dual-energy subtraction chest radiography.

    Science.gov (United States)

    Li, Feng; Engelmann, Roger; Pesce, Lorenzo L; Doi, Kunio; Metz, Charles E; Macmahon, Heber

    2011-12-01

    To determine whether use of bone suppression (BS) imaging, used together with a standard radiograph, could improve radiologists' performance for detection of small lung cancers compared with use of standard chest radiographs alone and whether BS imaging would provide accuracy equivalent to that of dual-energy subtraction (DES) radiography. Institutional review board approval was obtained. The requirement for informed consent was waived. The study was HIPAA compliant. Standard and DES chest radiographs of 50 patients with 55 confirmed primary nodular cancers (mean diameter, 20 mm) as well as 30 patients without cancers were included in the observer study. A new BS imaging processing system that can suppress the conspicuity of bones was applied to the standard radiographs to create corresponding BS images. Ten observers, including six experienced radiologists and four radiology residents, indicated their confidence levels regarding the presence or absence of a lung cancer for each lung, first by using a standard image, then a BS image, and finally DES soft-tissue and bone images. Receiver operating characteristic (ROC) analysis was used to evaluate observer performance. The average area under the ROC curve (AUC) for all observers was significantly improved from 0.807 to 0.867 with BS imaging and to 0.916 with DES (both P chest radiographs. Further improvements can be achieved by use of DES radiography but with the requirement for special equipment and a potential small increase in radiation dose. © RSNA, 2011.

  16. The value of subtraction MRI in detection of amyloid-related imaging abnormalities with oedema or effusion in Alzheimer's patients. An interobserver study

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Roland M.; Bechten, Arianne; Ingala, Silvia; Schijndel, Ronald A. van; Machado, Vania B.; Jong, Marcus C. de; Sanchez, Esther; Wattjes, Mike P. [VU University Medical Center, Department of Radiology and Nuclear Medicine, Neuroscience Campus Amsterdam (Netherlands); Purcell, Derk [California Pacific Medical Center, Department of Radiology, San Francisco, CA (United States); BioClinica Inc, Newark, CA (United States); Arrighi, Michael H.; Brashear, Robert H. [Janssen Alzheimer Immunotherapy Research and Development, LLC, South San Francisco, CA (United States); Barkhof, Frederik [VU University Medical Center, Department of Radiology and Nuclear Medicine, Neuroscience Campus Amsterdam (Netherlands); University College London, Institutes of Neurology and Healthcare Engineering, London (United Kingdom)

    2018-03-15

    Immunotherapeutic treatments targeting amyloid-β plaques in Alzheimer's disease (AD) are associated with the presence of amyloid-related imaging abnormalities with oedema or effusion (ARIA-E), whose detection and classification is crucial to evaluate subjects enrolled in clinical trials. To investigate the applicability of subtraction MRI in the ARIA-E detection using an established ARIA-E-rating scale. We included 75 AD patients receiving bapineuzumab treatment, including 29 ARIA-E cases. Five neuroradiologists rated their brain MRI-scans with and without subtraction images. The accuracy of evaluating the presence of ARIA-E, intraclass correlation coefficient (ICC) and specific agreement was calculated. Subtraction resulted in higher sensitivity (0.966) and lower specificity (0.970) than native images (0.959, 0.991, respectively). Individual rater detection was excellent. ICC scores ranged from excellent to good, except for gyral swelling (moderate). Excellent negative and good positive specific agreement among all ARIA-E imaging features was reported in both groups. Combining sulcal hyperintensity and gyral swelling significantly increased positive agreement for subtraction images. Subtraction MRI has potential as a visual aid increasing the sensitivity of ARIA-E assessment. However, in order to improve its usefulness isotropic acquisition and enhanced training are required. The ARIA-E rating scale may benefit from combining sulcal hyperintensity and swelling. (orig.)

  17. The value of subtraction MRI in detection of amyloid-related imaging abnormalities with oedema or effusion in Alzheimer's patients. An interobserver study

    International Nuclear Information System (INIS)

    Martens, Roland M.; Bechten, Arianne; Ingala, Silvia; Schijndel, Ronald A. van; Machado, Vania B.; Jong, Marcus C. de; Sanchez, Esther; Wattjes, Mike P.; Purcell, Derk; Arrighi, Michael H.; Brashear, Robert H.; Barkhof, Frederik

    2018-01-01

    Immunotherapeutic treatments targeting amyloid-β plaques in Alzheimer's disease (AD) are associated with the presence of amyloid-related imaging abnormalities with oedema or effusion (ARIA-E), whose detection and classification is crucial to evaluate subjects enrolled in clinical trials. To investigate the applicability of subtraction MRI in the ARIA-E detection using an established ARIA-E-rating scale. We included 75 AD patients receiving bapineuzumab treatment, including 29 ARIA-E cases. Five neuroradiologists rated their brain MRI-scans with and without subtraction images. The accuracy of evaluating the presence of ARIA-E, intraclass correlation coefficient (ICC) and specific agreement was calculated. Subtraction resulted in higher sensitivity (0.966) and lower specificity (0.970) than native images (0.959, 0.991, respectively). Individual rater detection was excellent. ICC scores ranged from excellent to good, except for gyral swelling (moderate). Excellent negative and good positive specific agreement among all ARIA-E imaging features was reported in both groups. Combining sulcal hyperintensity and gyral swelling significantly increased positive agreement for subtraction images. Subtraction MRI has potential as a visual aid increasing the sensitivity of ARIA-E assessment. However, in order to improve its usefulness isotropic acquisition and enhanced training are required. The ARIA-E rating scale may benefit from combining sulcal hyperintensity and swelling. (orig.)

  18. Self-masking noise subtraction (SMNS) in digital X-ray tomosynthesis for the improvement of tomographic image quality

    International Nuclear Information System (INIS)

    Oh, J.E.; Cho, H.S.; Choi, S.I.; Park, Y.O.; Lee, M.S.; Cho, H.M.; Yang, Y.J.; Je, U.K.; Woo, T.H.; Lee, H.K.

    2011-01-01

    In this paper, we proposed a simple and effective reconstruction algorithm, the so-called self-masking noise subtraction (SMNS), in digital X-ray tomosynthesis to reduce the tomographic blur that is inherent in the conventional tomosynthesis based upon the shift-and-add (SAA) method. Using the SAA and the SMNS algorithms, we investigated the influence of tomographic parameters such as tomographic angle (θ) and angle step (Δθ) on the image quality, measuring the signal-difference-to-noise ratio (SDNR). Our simulation results show that the proposed algorithm seems to be efficient in reducing the tomographic blur and, thus, improving image sharpness. We expect the simulation results to be useful for the optimal design of a digital X-ray tomosynthesis system for our ongoing application of nondestructive testing (NDT).

  19. A Monte Carlo simulation study of an improved K-edge log-subtraction X-ray imaging using a photon counting CdTe detector

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngjin, E-mail: radioyoungj@gmail.com [Department of Radiological Science, Eulji University, 553, Sanseong-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do (Korea, Republic of); Lee, Amy Candy [Department of Mathematics and Statistics, McGill University (Canada); Kim, Hee-Joung [Department of Radiological Science and Radiation Convergence Engineering, Yonsei University (Korea, Republic of)

    2016-09-11

    Recently, significant effort has been spent on the development of photons counting detector (PCD) based on a CdTe for applications in X-ray imaging system. The motivation of developing PCDs is higher image quality. Especially, the K-edge subtraction (KES) imaging technique using a PCD is able to improve image quality and useful for increasing the contrast resolution of a target material by utilizing contrast agent. Based on above-mentioned technique, we presented an idea for an improved K-edge log-subtraction (KELS) imaging technique. The KELS imaging technique based on the PCDs can be realized by using different subtraction energy width of the energy window. In this study, the effects of the KELS imaging technique and subtraction energy width of the energy window was investigated with respect to the contrast, standard deviation, and CNR with a Monte Carlo simulation. We simulated the PCD X-ray imaging system based on a CdTe and polymethylmethacrylate (PMMA) phantom which consists of the various iodine contrast agents. To acquired KELS images, images of the phantom using above and below the iodine contrast agent K-edge absorption energy (33.2 keV) have been acquired at different energy range. According to the results, the contrast and standard deviation were decreased, when subtraction energy width of the energy window is increased. Also, the CNR using a KELS imaging technique is higher than that of the images acquired by using whole energy range. Especially, the maximum differences of CNR between whole energy range and KELS images using a 1, 2, and 3 mm diameter iodine contrast agent were acquired 11.33, 8.73, and 8.29 times, respectively. Additionally, the optimum subtraction energy width of the energy window can be acquired at 5, 4, and 3 keV for the 1, 2, and 3 mm diameter iodine contrast agent, respectively. In conclusion, we successfully established an improved KELS imaging technique and optimized subtraction energy width of the energy window, and based on

  20. A background subtraction routine for enhancing energy-filtered plasmon images of MgAl2O4 implanted with Al+ and Mg+ ions

    International Nuclear Information System (INIS)

    Evans, N.D.; Kenik, E.A.; Bentley, J.; Zinkle, S.J.

    1995-01-01

    MgAl 2 O 4 , a candidate fusion reactor material, was irradiated with Al + or Mg + ions; electron energy-loss spectra and energy-filtered plasmon images showed that metallic Al colloids are present in the ion-irradiated regions. This paper shows the subtraction of the spinel plasmon component in images using 15-eV-loss electrons in some detail

  1. Identification of hand motion using background subtraction method and extraction of image binary with backpropagation neural network on skeleton model

    Science.gov (United States)

    Fauziah; Wibowo, E. P.; Madenda, S.; Hustinawati

    2018-03-01

    Capturing and recording motion in human is mostly done with the aim for sports, health, animation films, criminality, and robotic applications. In this study combined background subtraction and back propagation neural network. This purpose to produce, find similarity movement. The acquisition process using 8 MP resolution camera MP4 format, duration 48 seconds, 30frame/rate. video extracted produced 1444 pieces and results hand motion identification process. Phase of image processing performed is segmentation process, feature extraction, identification. Segmentation using bakground subtraction, extracted feature basically used to distinguish between one object to another object. Feature extraction performed by using motion based morfology analysis based on 7 invariant moment producing four different classes motion: no object, hand down, hand-to-side and hands-up. Identification process used to recognize of hand movement using seven inputs. Testing and training with a variety of parameters tested, it appears that architecture provides the highest accuracy in one hundred hidden neural network. The architecture is used propagate the input value of the system implementation process into the user interface. The result of the identification of the type of the human movement has been clone to produce the highest acuracy of 98.5447%. The training process is done to get the best results.

  2. Physician evaluation and acceptance of remote transmission of CT, digital subtraction angiography, and US annotated images

    International Nuclear Information System (INIS)

    Haskin, M.E.; Robbins, C.; Kohn, M.; Laffey, P.A.; Haskin, P.H.; Teplick, J.G.; Teplick, S.K.; Peyster, R.G.

    1986-01-01

    The authors have found annotated images an effective way of communicating the results of imaging studies to referring physicians. Of particular value is the collation of representative images from several modalities. Previously, hard copy of this collation was sent to the referring physician as an integrated imaging report. Recently they developed a computer-based station that transmits annotated images to remote personal computer (PC) terminals via a telephone modem which requires 30 seconds to send each image. This annotated image report can be quickly accessed by the referring physician at the remote PC terminal The prototype system, utility, diagnostic fidelity, and potential of this remote system are described

  3. Evaluation of the Accuracy of the Dark Frame Subtraction Method in CCD Image Processing

    National Research Council Canada - National Science Library

    Levesque, Martin P; Lelievre, Mario

    2007-01-01

    .... This method is frequently used for removing the image background gradient (a thermal artefact) in CCD images. This report demonstrates that this method may not be suitable for the detection of objects with very low signal-to-noise ratio...

  4. Use of images of ictal-inter-ictal SPECT subtraction superimposed on MRI in pharmaco-resistant partial epilepsies in infants

    International Nuclear Information System (INIS)

    Vera, P.; Kaminska, A.; Cieuta, C.; Mangin, F.; Frouin, V.; Dulac, O.; Chiron, C.

    1997-01-01

    To study the significance of ictal SPECT in the pre-surgical examination of infant epilepsies we have explored 16 infants aged 3 months to 18 years presenting partial pharmaco-resistant epilepsy. All of them have had an ictal SPECT under EEG - video recording than, two days after, an inter-ictal SPECT coupled to a 3D cerebral MRI. The perfusion tracer, the 99m Tc - ECD, was injected in average at 15 seconds after the outset of crisis. The image processing implied a matching of the two SPECT examinations by a 3D rigid superposition method, a normalization and than a inter-ictal-ictal image subtraction. Finally, the subtraction was matched and superimposed on the MRI. The SPECT subtraction image showed one or several centres of ictal hyper-output in 15 patients, while the separated visual ictal and inter-ictal images were contributory in 8 cases only. The 16. infant presented very short crises (<10 sec). In the cases when the outset point of crises could be established clinically (12 cases) and/or on EEG (8 cases) a hyper-output of concordant localization was recorded. In 5 infants who have had an electrocorticography, a concordance was obtained in all the cases except in an infant having very short crises the subtraction image did not show hyper-output. These preliminary results show that the ictal - inter-ictal SPECT subtraction images, adjusted on MRI, appears to be reliable in detecting the outset point of crises in infants and at the same time useful in guiding the positioning of intra-cranial electrodes prior to surgery intervention

  5. Combined dynamic contrast-enhancement and serial 3D-subtraction analysis in magnetic resonance imaging of osteoid osteomas

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, T. von; Winkler, P. [Klinikum Stuttgart Olgahospital, Department of Paediatric Radiology, Stuttgart (Germany); Langendoerfer, M.; Fernandez, F.F. [Klinikum Stuttgart Olgahospital, Department of Paediatric Orthopaedics, Stuttgart (Germany)

    2009-10-15

    The purpose of this study was to retrospectively correlate the results of dynamic contrast-enhanced magnetic resonance imaging (MRI) with histological and clinical diagnoses in patients with osteoid osteomas. Fifty-four patients with the MR diagnosis of osteoid osteoma were studied. MRI (1.5 Tesla) consisted of thin-section STIR sequences, dynamic 3D T1 gradient echo sequences during application of contrast material, and high-resolution postcontrast T1 spin echo sequences with fat saturation (maximum voxel size 0.6 x 0.6 x 3.0 mm). Evaluation was focused on serial image subtraction during the early phase after contrast injection and on time-intensity curves. The surrounding edema was helpful in finding the nidus in each lesion. In 49 of 54 patients (90.7%), the diagnosis of osteoid osteoma was certain or highly probable (sensitivity 1.0, positive predictive value 0.91). A total of 38 of 54 osteoid osteomas were histologically proven. Five MRI diagnoses were regarded as false positives. A similar proportion has been reported for computed tomography. Tailored high-resolution MR examinations with dynamic contrast enhancement can reliably diagnose osteoid osteomas and exactly localize the nidus without radiation exposure. We propose a stepwise approach with STIR sequences, dynamic contrast-enhanced scanning, and high-resolution postcontrast T1 spin echo sequences with fat saturation. (orig.)

  6. Combined dynamic contrast-enhancement and serial 3D-subtraction analysis in magnetic resonance imaging of osteoid osteomas

    International Nuclear Information System (INIS)

    Kalle, T. von; Winkler, P.; Langendoerfer, M.; Fernandez, F.F.

    2009-01-01

    The purpose of this study was to retrospectively correlate the results of dynamic contrast-enhanced magnetic resonance imaging (MRI) with histological and clinical diagnoses in patients with osteoid osteomas. Fifty-four patients with the MR diagnosis of osteoid osteoma were studied. MRI (1.5 Tesla) consisted of thin-section STIR sequences, dynamic 3D T1 gradient echo sequences during application of contrast material, and high-resolution postcontrast T1 spin echo sequences with fat saturation (maximum voxel size 0.6 x 0.6 x 3.0 mm). Evaluation was focused on serial image subtraction during the early phase after contrast injection and on time-intensity curves. The surrounding edema was helpful in finding the nidus in each lesion. In 49 of 54 patients (90.7%), the diagnosis of osteoid osteoma was certain or highly probable (sensitivity 1.0, positive predictive value 0.91). A total of 38 of 54 osteoid osteomas were histologically proven. Five MRI diagnoses were regarded as false positives. A similar proportion has been reported for computed tomography. Tailored high-resolution MR examinations with dynamic contrast enhancement can reliably diagnose osteoid osteomas and exactly localize the nidus without radiation exposure. We propose a stepwise approach with STIR sequences, dynamic contrast-enhanced scanning, and high-resolution postcontrast T1 spin echo sequences with fat saturation. (orig.)

  7. Variability-based active galactic nucleus selection using image subtraction in the SDSS and LSST era

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yumi; Gibson, Robert R.; Becker, Andrew C.; Ivezić, Željko; Connolly, Andrew J.; Ruan, John J.; Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); MacLeod, Chelsea L., E-mail: ymchoi@astro.washington.edu [Physics Department, U.S. Naval Academy, 572 Holloway Road, Annapolis, MD 21402 (United States)

    2014-02-10

    With upcoming all-sky surveys such as LSST poised to generate a deep digital movie of the optical sky, variability-based active galactic nucleus (AGN) selection will enable the construction of highly complete catalogs with minimum contamination. In this study, we generate g-band difference images and construct light curves (LCs) for QSO/AGN candidates listed in Sloan Digital Sky Survey Stripe 82 public catalogs compiled from different methods, including spectroscopy, optical colors, variability, and X-ray detection. Image differencing excels at identifying variable sources embedded in complex or blended emission regions such as Type II AGNs and other low-luminosity AGNs that may be omitted from traditional photometric or spectroscopic catalogs. To separate QSOs/AGNs from other sources using our difference image LCs, we explore several LC statistics and parameterize optical variability by the characteristic damping timescale (τ) and variability amplitude. By virtue of distinguishable variability parameters of AGNs, we are able to select them with high completeness of 93.4% and efficiency (i.e., purity) of 71.3%. Based on optical variability, we also select highly variable blazar candidates, whose infrared colors are consistent with known blazars. One-third of them are also radio detected. With the X-ray selected AGN candidates, we probe the optical variability of X-ray detected optically extended sources using their difference image LCs for the first time. A combination of optical variability and X-ray detection enables us to select various types of host-dominated AGNs. Contrary to the AGN unification model prediction, two Type II AGN candidates (out of six) show detectable variability on long-term timescales like typical Type I AGNs. This study will provide a baseline for future optical variability studies of extended sources.

  8. An automatic fuzzy-based multi-temporal brain digital subtraction angiography image fusion algorithm using curvelet transform and content selection strategy.

    Science.gov (United States)

    Momeni, Saba; Pourghassem, Hossein

    2014-08-01

    Recently image fusion has prominent role in medical image processing and is useful to diagnose and treat many diseases. Digital subtraction angiography is one of the most applicable imaging to diagnose brain vascular diseases and radiosurgery of brain. This paper proposes an automatic fuzzy-based multi-temporal fusion algorithm for 2-D digital subtraction angiography images. In this algorithm, for blood vessel map extraction, the valuable frames of brain angiography video are automatically determined to form the digital subtraction angiography images based on a novel definition of vessel dispersion generated by injected contrast material. Our proposed fusion scheme contains different fusion methods for high and low frequency contents based on the coefficient characteristic of wrapping second generation of curvelet transform and a novel content selection strategy. Our proposed content selection strategy is defined based on sample correlation of the curvelet transform coefficients. In our proposed fuzzy-based fusion scheme, the selection of curvelet coefficients are optimized by applying weighted averaging and maximum selection rules for the high frequency coefficients. For low frequency coefficients, the maximum selection rule based on local energy criterion is applied to better visual perception. Our proposed fusion algorithm is evaluated on a perfect brain angiography image dataset consisting of one hundred 2-D internal carotid rotational angiography videos. The obtained results demonstrate the effectiveness and efficiency of our proposed fusion algorithm in comparison with common and basic fusion algorithms.

  9. Contrast-enhanced MR angiography vs intra-arterial digital subtraction angiography for carotid imaging: activity-based cost analysis

    International Nuclear Information System (INIS)

    U-King-Im, Jean Marie; Cross, Justin J.; Higgins, Nicholas J.; Graves, Martin J.; Antoun, Nagui M.; Gillard, Jonathan H.; Hollingworth, William; Trivedi, Rikin A.; Kirkpatrick, Peter J.

    2004-01-01

    The aim of this study was to compare the costs of performing contrast-enhanced MR angiography (CE MRA) with intra-arterial digital subtraction angiography (DSA) for the evaluation of carotid atherosclerotic disease. Activity-based cost analysis was used to identify the costs of performing each procedure. The variable direct costs of performing CE MRA and DSA were determined in 20 patients by using detailed time and motion studies. All personnel directly involved in the cases were tracked to the nearest minute and all consumable items used were recorded. Moreover, procedure times were prospectively recorded for an additional 80 patients who underwent both DSA and CE MRA. The variable direct costs of bed usage in the angiography day-case unit, all direct fixed costs as well as indirect costs were assessed from hospital and departmental accounting records. Total costs for each procedure were calculated and compared using Wilcoxon signed-rank sum test. Mean aggregate costs were and euro;721 for DSA and and euro;306 for CE MRA, resulting in potential savings of and euro;415 per patient (p<0.0001). On average, a DSA procedure thus cost approximately 2.4 (95% confidence intervals: 2.2-2.6) times more than CE MRA to our medical institution. Sensitivity analyses confirmed the robustness of our conclusions across wide ranges of plausible values for various parameters. Assuming equal diagnostic performance, institutions may have substantial cost savings if CE MRA is used instead of DSA for carotid imaging. (orig.)

  10. Contrast-enhanced MR angiography vs intra-arterial digital subtraction angiography for carotid imaging: activity-based cost analysis

    Energy Technology Data Exchange (ETDEWEB)

    U-King-Im, Jean Marie; Cross, Justin J.; Higgins, Nicholas J.; Graves, Martin J.; Antoun, Nagui M.; Gillard, Jonathan H. [University Department of Radiology, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom); Hollingworth, William [Department of Radiology, University of Washington, WA 98103, Seattle (United States); Trivedi, Rikin A. [University Department of Radiology, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom); Academic Department of Neurosurgery, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom); Kirkpatrick, Peter J. [Academic Department of Neurosurgery, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom)

    2004-04-01

    The aim of this study was to compare the costs of performing contrast-enhanced MR angiography (CE MRA) with intra-arterial digital subtraction angiography (DSA) for the evaluation of carotid atherosclerotic disease. Activity-based cost analysis was used to identify the costs of performing each procedure. The variable direct costs of performing CE MRA and DSA were determined in 20 patients by using detailed time and motion studies. All personnel directly involved in the cases were tracked to the nearest minute and all consumable items used were recorded. Moreover, procedure times were prospectively recorded for an additional 80 patients who underwent both DSA and CE MRA. The variable direct costs of bed usage in the angiography day-case unit, all direct fixed costs as well as indirect costs were assessed from hospital and departmental accounting records. Total costs for each procedure were calculated and compared using Wilcoxon signed-rank sum test. Mean aggregate costs were and euro;721 for DSA and and euro;306 for CE MRA, resulting in potential savings of and euro;415 per patient (p<0.0001). On average, a DSA procedure thus cost approximately 2.4 (95% confidence intervals: 2.2-2.6) times more than CE MRA to our medical institution. Sensitivity analyses confirmed the robustness of our conclusions across wide ranges of plausible values for various parameters. Assuming equal diagnostic performance, institutions may have substantial cost savings if CE MRA is used instead of DSA for carotid imaging. (orig.)

  11. Digital subtraction angiography

    International Nuclear Information System (INIS)

    Neuwirth, J. Jr.; Bohutova, J.

    1987-01-01

    The quality of radiodiagnostic methods to a great extent depends on the quality of the resulting image. The basic technical principles are summed up of the different parts of digital subtraction angiography apparatus and of methods of improving the image. The instrument is based on a videochain consisting of an X-ray tube, an intensifier of the radiographic image, optical parts, a video camera, an analog-to-digital converter and a computer. The main advantage of the digitally processed image is the possibility of optimizing the image into a form which will contain the biggest amount of diagnostically valuable information. Described are the mathematical operations for improving the digital image: spatial filtration, pixel shift, time filtration, image integration, time interval differentation and matched filtering. (M.D.). 8 refs., 3 figs

  12. Radiation dose and image quality of X-ray volume imaging systems: cone-beam computed tomography, digital subtraction angiography and digital fluoroscopy.

    Science.gov (United States)

    Paul, Jijo; Jacobi, Volkmar; Farhang, Mohammad; Bazrafshan, Babak; Vogl, Thomas J; Mbalisike, Emmanuel C

    2013-06-01

    Radiation dose and image quality estimation of three X-ray volume imaging (XVI) systems. A total of 126 patients were examined using three XVI systems (groups 1-3) and their data were retrospectively analysed from 2007 to 2012. Each group consisted of 42 patients and each patient was examined using cone-beam computed tomography (CBCT), digital subtraction angiography (DSA) and digital fluoroscopy (DF). Dose parameters such as dose-area product (DAP), skin entry dose (SED) and image quality parameters such as Hounsfield unit (HU), noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were estimated and compared using appropriate statistical tests. Mean DAP and SED were lower in recent XVI than its previous counterparts in CBCT, DSA and DF. HU of all measured locations was non-significant between the groups except the hepatic artery. Noise showed significant difference among groups (P < 0.05). Regarding CNR and SNR, the recent XVI showed a higher and significant difference compared to its previous versions. Qualitatively, CBCT showed significance between versions unlike the DSA and DF which showed non-significance. A reduction of radiation dose was obtained for the recent-generation XVI system in CBCT, DSA and DF. Image noise was significantly lower; SNR and CNR were higher than in previous versions. The technological advancements and the reduction in the number of frames led to a significant dose reduction and improved image quality with the recent-generation XVI system. • X-ray volume imaging (XVI) systems are increasingly used for interventional radiological procedures. • More modern XVI systems use lower radiation doses compared with earlier counterparts. • Furthermore more modern XVI systems provide higher image quality. • Technological advances reduce radiation dose and improve image quality.

  13. Three-dimensional ultrashort echo time MRI and Short T2 images generated from subtraction for determination of tumor burden in lung cancer: Preclinical investigation in transgenic mice.

    Science.gov (United States)

    Müller, Andreas; Jagoda, Philippe; Fries, Peter; Gräber, Stefan; Bals, Robert; Buecker, Arno; Jungnickel, Christopher; Beisswenger, Christoph

    2018-02-01

    To investigate the potential of 3D ultrashort echo time MRI and short T 2 images generated by subtraction for determination of total tumor burden in lung cancer. As an animal model of spontaneously developing non-small cell lung cancer, the K-rasLA1 transgenic mouse was used. Three-dimensional MR imaging was performed with radial k-space acquisition and echo times of 20 µs and 1 ms. For investigation of the short T 2 component in the recorded signal, subtraction images were generated from these data sets and used for consensus identification of tumors. Next, manual segmentation was performed on all MR images by two independent investigators. MRI data were compared with the results from histologic investigations and among the investigators. Tumor number and total tumor burden from imaging experiments correlated strongly with the results of histologic investigations. Intra- and interuser comparison showed highest correlations between the individual measurements for ultra-short TE MRI. Three-dimensional MRI protocols facilitate accurate tumor identification in mice harboring lung tumors. Ultrashort TE MRI is the superior imaging strategy when investigating lung tumors of miscellaneous size with 3D MR imaging strategies. Magn Reson Med 79:1052-1060, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  14. Material decomposition through weighted imaged subtraction in dual-energy spectral mammography with an energy-resolved photon-counting detector using Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Ji Soo; Kang, Soon Cheol; Lee, Seung Wan [Konyang University, Daejeon (Korea, Republic of)

    2017-09-15

    Mammography is commonly used for screening early breast cancer. However, mammographic images, which depend on the physical properties of breast components, are limited to provide information about whether a lesion is malignant or benign. Although a dual-energy subtraction technique decomposes a certain material from a mixture, it increases radiation dose and degrades the accuracy of material decomposition. In this study, we simulated a breast phantom using attenuation characteristics, and we proposed a technique to enable the accurate material decomposition by applying weighting factors for the dual-energy mammography based on a photon-counting detector using a Monte Carlo simulation tool. We also evaluated the contrast and noise of simulated breast images for validating the proposed technique. As a result, the contrast for a malignant tumor in the dual-energy weighted subtraction technique was 0.98 and 1.06 times similar than those in the general mammography and dual-energy subtraction techniques, respectively. However the contrast between malignant and benign tumors dramatically increased 13.54 times due to the low contrast of a benign tumor. Therefore, the proposed technique can increase the material decomposition accuracy for malignant tumor and improve the diagnostic accuracy of mammography.

  15. Intraarterial digital subtraction angiography

    International Nuclear Information System (INIS)

    Davis, P.C.

    1987-01-01

    Digital subtraction angiography (DSA) refers to a radiographic technique of amplifying low levels of contrast from intravascular iodine into an acceptable image of vascular anatomy. Initial enthusiasm suggested that DSA using intravenous injections (IV-DSA) would eliminate most conventional film-screen angiographic studies. It was soon apparent, however, that IV-DSA examinations were often compromised in those patients who most needed a less invasive study. Indeed, only a 70 to 85 percent accuracy rate was achieved with IV-DSA, primarily due to motion artifact, poor cardiac output, overlap of pertinent vessels, and inability to resolve smaller vessels

  16. Real-time out-of-plane artifact subtraction tomosynthesis imaging using prior CT for scanning beam digital x-ray system

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng, E-mail: mengwu@stanford.edu [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2014-11-01

    Purpose: The scanning beam digital x-ray system (SBDX) is an inverse geometry fluoroscopic system with high dose efficiency and the ability to perform continuous real-time tomosynthesis in multiple planes. This system could be used for image guidance during lung nodule biopsy. However, the reconstructed images suffer from strong out-of-plane artifact due to the small tomographic angle of the system. Methods: The authors propose an out-of-plane artifact subtraction tomosynthesis (OPAST) algorithm that utilizes a prior CT volume to augment the run-time image processing. A blur-and-add (BAA) analytical model, derived from the project-to-backproject physical model, permits the generation of tomosynthesis images that are a good approximation to the shift-and-add (SAA) reconstructed image. A computationally practical algorithm is proposed to simulate images and out-of-plane artifacts from patient-specific prior CT volumes using the BAA model. A 3D image registration algorithm to align the simulated and reconstructed images is described. The accuracy of the BAA analytical model and the OPAST algorithm was evaluated using three lung cancer patients’ CT data. The OPAST and image registration algorithms were also tested with added nonrigid respiratory motions. Results: Image similarity measurements, including the correlation coefficient, mean squared error, and structural similarity index, indicated that the BAA model is very accurate in simulating the SAA images from the prior CT for the SBDX system. The shift-variant effect of the BAA model can be ignored when the shifts between SBDX images and CT volumes are within ±10 mm in the x and y directions. The nodule visibility and depth resolution are improved by subtracting simulated artifacts from the reconstructions. The image registration and OPAST are robust in the presence of added respiratory motions. The dominant artifacts in the subtraction images are caused by the mismatches between the real object and the prior CT

  17. Digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Ludwig, J.W.; Eikelboom, B.C.; Van Schaik, C.C.; Taams, A.J.; Teeuwen, C.

    1985-01-01

    Besides the non-invasive techniques, angiography remains essential. The disadvantages of angiography are the complexity of the procedure and the possibility of complications. Digital subtraction angiography (DSA) is a considerable improvement in the examination of vessels. In DSA, subtraction combined with enhancement of the signals allows the use of intravenous injection to obtain good images of the arteries. However, when the contrast material is supplied intravenously, a rather large amount of contrast material is necessary to obtain images of good quality. Quantities of 30-40 cc of contrast material are required. The advantage of the intravenous injection of contrast material rather than the use of a catheter to deliver the contrast material in loco is that it is almost non-invasive thus circumventing the complications caused by catheter manipulation in the arterial system. This makes it possible to apply this method on an out-patient basis. DSA can also be applied with intra-arterial selective injection of the contrast material. In this case, the strong enhancement with DSA allows the use of a small quantity of contrast material while still obtaining images of the vessels with good contrast definition

  18. Self-masking subtraction tomosynthesis

    International Nuclear Information System (INIS)

    Chakraborty, D.P.; Yester, M.V.; Barnes, G.T.; Lakshminarayanan, A.V.

    1984-01-01

    The authors tested the image quality and dose savings of self-masking subtraction tomosynthesis (SST), which combines digital tomosynthesis with subtraction of a blurred self-mask. High-quality images of the inner ear of a head phantom were obtained at moderate dose savings. Although they were taken with linear motion, they did not exhibit the streaking due to off-fulcrum objects that is characteristic of conventional linear tomography. SST could reduce patient dose by a factor of at least 12 in examinations of the inner ear, and the mechanical aspects can be implemented with moderate modifications of existing instrumentation

  19. Fluorescence background subtraction technique for hybrid fluorescence molecular tomography/x-ray computed tomography imaging of a mouse model of early stage lung cancer.

    Science.gov (United States)

    Ale, Angelique; Ermolayev, Vladimir; Deliolanis, Nikolaos C; Ntziachristos, Vasilis

    2013-05-01

    The ability to visualize early stage lung cancer is important in the study of biomarkers and targeting agents that could lead to earlier diagnosis. The recent development of hybrid free-space 360-deg fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) imaging yields a superior optical imaging modality for three-dimensional small animal fluorescence imaging over stand-alone optical systems. Imaging accuracy was improved by using XCT information in the fluorescence reconstruction method. Despite this progress, the detection sensitivity of targeted fluorescence agents remains limited by nonspecific background accumulation of the fluorochrome employed, which complicates early detection of murine cancers. Therefore we examine whether x-ray CT information and bulk fluorescence detection can be combined to increase detection sensitivity. Correspondingly, we research the performance of a data-driven fluorescence background estimator employed for subtraction of background fluorescence from acquisition data. Using mice containing known fluorochromes ex vivo, we demonstrate the reduction of background signals from reconstructed images and sensitivity improvements. Finally, by applying the method to in vivo data from K-ras transgenic mice developing lung cancer, we find small tumors at an early stage compared with reconstructions performed using raw data. We conclude with the benefits of employing fluorescence subtraction in hybrid FMT-XCT for early detection studies.

  20. The comparison of Tc99m-pertechnetate/mibi subtraction and double phase Tc99m-mibi techniques in parathyroid imaging

    International Nuclear Information System (INIS)

    Bilkay, Ue.; Erinc, R.; Karapolat, I.; Kumanlioglu, K.

    2001-01-01

    Experienced parathyroid surgeons can localize nearly %90-95 of the abnormal parathyroid glands with total thyroid bed exploration. For this reason, for the first surgical exploration preoperative imaging of the gland could be considered unnecessary. However, localization of the abnormal parathyroid tissue preoperatively could be beneficial in ectopic adenomas which consists %20 of all adenomas and also in shortening surgical procedure in single adenomas with the use of unilateral exploration. Re-exploration after an unsuccessful surgery is the most widely accepted indication for parathyroid imaging. Today, although Tc99m-MIBI is the accepted radionuclide with the advantages of giving better image quality with lower radiation dose over Tl-201, for imaging hyper functioning parathyroid tissue, there is no consensus on the ideal imaging protocol. Single-tracer double-phase imaging (STDP) and dual-tracer subtraction technique (Tc99m-pertechnetate/Tc99m-MIBI) (DTST) are proposed protocols using Tc99m-MIBI. The aim of this ongoing study is; to compare STDP imaging with DTST and to compare sensitivity of pinhole and high resolution parallel hole images in STDP protocol

  1. sup(99m)Tc particle perfusion/sup(99m)Tc aerosol ventilation imaging using a subtraction technique in suspected pulmonary embolism

    International Nuclear Information System (INIS)

    Poeyhoenen, L.; Turjanmaa, V.; Virjo, A.

    1985-01-01

    It is generally acknowledged that ventilation-perfusion mismatch is diagnostic of pulmonary embolism. Lung ventilation imaging with radioactive gases is a good method for the detection of pulmonary embolism, but it is not in widespread use because of the limited availability of sup(81m)Kr gas and the poor physical properties of 133 Xe. Aerosols have been proposed, instead of gases for use in lung ventilation imaging. As perfusion and ventilation distributions may change very rapidly, the two imaging procedures should be done in rapid succession. The cheapest way to perform the combined perfusion-ventilation (Q/V) imaging is to use sup(99m)Tc-labelled macroaggregates and aerosols. In our method the perfusion imaging was done first, immediately followed by the ventilation imaging with sup(99m)Tc-labelled aerosols. A computer program was used to subtract the contribution of the perfusion from the combined Q/V image so that the pure ventilation image alone was obtained. The method was tested in 41 patients with suspected pulmonary embolism. (orig.)

  2. Digital subtraction angiography

    International Nuclear Information System (INIS)

    Gmelin, E.; Arlart, I.P.

    1987-01-01

    The introduction explains the technical and physical fundamentals of digital radiography, the principles of digital subtraction, and the various filtering methods. The authors then define the requirements to be met by a DSA equipment in terms of technical components and operational performance. A very extensive chapter deals with the indications supporting intravenous or intraarterial DSA and compares the two methods, showing advantages and drawbacks with respect to practical results. Another chapter discusses the applications of DSA for cardiological diagnostics, as e.g. imaging of the coronary arteries or arterial bypasses, and explains the densitometric and planimetric evaluation of the coronary functional processes. The book also discusses less customary applications of DSA such as the sialography or dacryocystography, as well as angiologic examinations in children. The limits of the DSA methods are discussed in the last chapter, together with aspects such as the radiation exposure of the patient, and cost-benefit analyses, and potential future improvements. With 204 figs., 44 tabs [de

  3. Tests of variable-band multilayers designed for investigating optimal signal-to-noise vs artifact signal ratios in Dual-Energy Digital Subtraction Angiography (DDSA) imaging systems

    International Nuclear Information System (INIS)

    Boyers, D.; Ho, A.; Li, Q.; Piestrup, M.; Rice, M.; Tatchyn, R.

    1993-08-01

    In recent work, various design techniques were applied to investigate the feasibility of controlling the bandwidth and bandshape profiles of tungsten/boron-carbon (W/B 4 C) and tungsten/silicon (W/Si) multilayers for optimizing their performance in synchrotron radiation based angiographical imaging systems at 33 keV. Varied parameters included alternative spacing geometries, material thickness ratios, and numbers of layer pairs. Planar optics with nominal design reflectivities of 30%--94% and bandwidths ranging from 0.6%--10% were designed at the Stanford Radiation Laboratory, fabricated by the Ovonic Synthetic Materials Company, and characterized on Beam Line 4-3 at the Stanford Synchrotron Radiation Laboratory, in this paper we report selected results of these tests and review the possible use of the multilayers for determining optimal signal to noise vs. artifact signal ratios in practical Dual-Energy Digital Subtraction Angiography systems

  4. TU-CD-207-03: Time Evolution of Texture Parameters of Subtracted Images Obtained by Contrast-Enhanced Digital Mammography (CEDM)

    Energy Technology Data Exchange (ETDEWEB)

    Mateos, M-J; Brandan, M-E [Instituto de Fisica, Universidad Nacional Autonom de Mexico, Mexico, Distrito Federal (Mexico); Gastelum, A; Marquez, J [Centro de Ciencias Aplicadas y Desarrollo Tecnologico Universidad Nacional Autonoma de Mexico, Mexico, Distrito Federal (Mexico)

    2015-06-15

    Purpose: To evaluate the time evolution of texture parameters, based on the gray level co-occurrence matrix (GLCM), in subtracted images of 17 patients (10 malignant and 7 benign) subjected to contrast-enhanced digital mammography (CEDM). The goal is to determine the sensitivity of texture to iodine uptake at the lesion, and its correlation (or lack of) with mean-pixel-value (MPV). Methods: Acquisition of clinical images followed a single-energy CEDM protocol using Rh/Rh/48 kV plus external 0.5 cm Al from a Senographe DS unit. Prior to the iodine-based contrast medium (CM) administration a mask image was acquired; four CM images were obtained 1, 2, 3, and 5 minutes after CM injection. Temporal series were obtained by logarithmic subtraction of registered CM minus mask images.Regions of interest (ROI) for the lesion were drawn by a radiologist and the texture was analyzed. GLCM was evaluated at a 3 pixel distance, 0° angle, and 64 gray-levels. Pixels identified as registration errors were excluded from the computation. 17 texture parameters were chosen, classified according to similarity into 7 groups, and analyzed. Results: In all cases the texture parameters within a group have similar dynamic behavior. Two texture groups (associated to cluster and sum mean) show a strong correlation with MPV; their average correlation coefficient (ACC) is r{sup 2}=0.90. Other two groups (contrast, homogeneity) remain constant with time, that is, a low-sensitivity to CM uptake. Three groups (regularity, lacunarity and diagonal moment) are sensitive to CM uptake but less correlated with MPV; their ACC is r{sup 2}=0.78. Conclusion: This analysis has shown that, at least groups associated to regularity, lacunarity and diagonal moment offer dynamical information additional to the mean pixel value due to the presence of CM at the lesion. The next step will be the analysis in terms of the lesion pathology. Authors thank PAPIIT-IN105813 for support. Consejo Nacional de Ciencia Y

  5. Left-right subtraction of brain CT

    International Nuclear Information System (INIS)

    Ishiguchi, Tsuneo; Sakuma, Sadayuki

    1986-01-01

    A new image-processing method to obtain a left-right subtraction image of CT was designed for the automated detection of abnormalities in brain CT. An original CT image was divided in two by a centerline. Then the right half of the image was subtracted from the left half by calculating the absorption value of the pixels on the symmetrical positions against the centerline. The mean and the standard deviation of the absorption value of the pixels in the subtraction image were used as parameters for analysis, and the detectability of abnormal CT findings was evaluated in 100 cases - 50 cases each with normal and abnormal CT. The presence of abnormalities could be diagnosed with a sensitivity of 86 %, a specificity of 90 %, and an overall accuracy of 88 % when the borderline of these parameters between normal and abnormal CT was set at the mean + 2SD in the normal group. As a further analysis, the CT image was subdivided into several areas from a functional or anatomical viewpoint, such as cerebral vascular territories, and the left-right subtraction image of each area was obtained. The possibilities of diagnosing the location of an abnormality and of detecting smaller lesions with this method were shown. Left-right subtraction was considered to be a useful method for the detection of asymmetric abnormalities in the automated diagnosis of brain CT. (author)

  6. Temporal subtraction of dual-energy chest radiographs

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Doshi, Devang J.; Engelmann, Roger; Caligiuri, Philip; MacMahon, Heber

    2006-01-01

    Temporal subtraction and dual-energy imaging are two enhanced radiography techniques that are receiving increased attention in chest radiography. Temporal subtraction is an image processing technique that facilitates the visualization of pathologic change across serial chest radiographic images acquired from the same patient; dual-energy imaging exploits the differential relative attenuation of x-ray photons exhibited by soft-tissue and bony structures at different x-ray energies to generate a pair of images that accentuate those structures. Although temporal subtraction images provide a powerful mechanism for enhancing visualization of subtle change, misregistration artifacts in these images can mimic or obscure abnormalities. The purpose of this study was to evaluate whether dual-energy imaging could improve the quality of temporal subtraction images. Temporal subtraction images were generated from 100 pairs of temporally sequential standard radiographic chest images and from the corresponding 100 pairs of dual-energy, soft-tissue radiographic images. The registration accuracy demonstrated in the resulting temporal subtraction images was evaluated subjectively by two radiologists. The registration accuracy of the soft-tissue-based temporal subtraction images was rated superior to that of the conventional temporal subtraction images. Registration accuracy also was evaluated objectively through an automated method, which achieved an area-under-the-ROC-curve value of 0.92 in the distinction between temporal subtraction images that demonstrated clinically acceptable and clinically unacceptable registration accuracy. By combining dual-energy soft-tissue images with temporal subtraction, misregistration artifacts can be reduced and superior image quality can be obtained

  7. Automatic dipole subtraction

    International Nuclear Information System (INIS)

    Hasegawa, K.

    2008-01-01

    The Catani-Seymour dipole subtraction is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. We automatized the procedure in a computer code. The code is useful especially for the processes with many parton legs. In this talk, we first explain the algorithm of the dipole subtraction and the whole structure of our code. After that we show the results for some processes where the infrared divergences of real emission processes are subtracted. (author)

  8. Digital subtraction angiography system evaluation with phantoms

    International Nuclear Information System (INIS)

    Wenstrup, R.S.; Sweeney, K.P.; Scholz, F.J.

    1985-01-01

    Advances in digital subtraction angiography imaging demonstrate the need for critical evaluation of the performance of digital subtraction equipment. The design of a phantom set for noninvasive assessment of the imaging quality of digital subtraction equipment is described; components include a remotely controlled transport system and individual patterns to evaluate the contrast and detail properties of the image intensifier, low-contrast sensitivity and resolution of the system, geometric distortion of image, linearity, mechanical and electronic stability of equipment, and effects of bone and bowel gas on iodine perception. The performance of an add-on digital radiographic system is presented, along with radiation exposure levels at the image intensifier for a range of radiographic techniques

  9. Non-enhanced magnetic resonance imaging of unruptured intracranial aneurysms at 7 Tesla: Comparison with digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, Karsten H.; Chen, Bixia [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Department of Neurosurgery, Essen (Germany); Matsushige, Toshinori [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Department of Neurosurgery, Essen (Germany); Hiroshima University, Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima (Japan); Goericke, Sophia L.; Umutlu, Lale; Forsting, Michael [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Quick, Harald H. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, High Field and Hybrid MR Imaging, Essen (Germany); Ladd, Mark E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); German Cancer Research Center (DKFZ), Division of Medical Physics in Radiology (E020), Heidelberg (Germany); Johst, Soeren [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Sure, Ulrich [University Hospital Essen, Department of Neurosurgery, Essen (Germany); Schlamann, Marc [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University Hospital Giessen, Department of Neuroradiology, Giessen (Germany)

    2017-01-15

    To prospectively evaluate non-contrast-enhanced 7-Tesla (T) MRA for delineation of unruptured intracranial aneurysms (UIAs) in comparison with DSA. Forty patients with single or multiple UIAs were enrolled in this IRB-approved trial. Sequences acquired at 7 T were TOF MRA and non-contrast-enhanced MPRAGE. All patients additionally underwent 3D rotational DSA. Two neuroradiologists individually analysed the following aneurysm and image features on a five-point scale in 2D and 3D image reconstructions: delineation of parent vessel, dome and neck; overall image quality; presence of artefacts. Interobserver accordance was assessed by the kappa coefficient. A total of 64 UIAs were detected in DSA and in all 2D and 3D MRA image reconstructions. Ratings showed comparable results for DSA and 7-T MRA when considering all image reconstructions. Highest ratings for individual image reconstructions were given for 2D MPRAGE and 3D TOF MRA. Interobserver accordance was almost perfect for the majority of ratings. This study demonstrates excellent delineation of UIAs using 7-T MRA within a clinical setting comparable to the gold standard, DSA. The combination of 7-T non-enhanced MPRAGE and TOF MRA for assessment of untreated UIAs is a promising clinical application of ultra-high-field MRA. (orig.)

  10. The value of magnetic resonance imaging for the detection of the bleeding source in non-traumatic intracerebral haemorrhages: a comparison with conventional digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lummel, Nina; Lutz, Juergen; Brueckmann, Hartmut; Linn, Jennifer [University of Munich, Department of Neuroradiology, Munich (Germany)

    2012-07-15

    Conventional digital subtraction angiography (DSA) is currently regarded as the gold standard in detecting underlying vascular pathologies in patients with intracerebral haemorrhages (ICH). However, the use of magnetic resonance imaging (MRI) in the diagnostic workup of ICHs has considerably increased in recent years. Our aim was to evaluate the diagnostic accuracy and yield of MRI for the detection of the underlying aetiology in ICH patients. Sixty-seven consecutive patients with an acute ICH who underwent MRI (including magnetic resonance angiography (MRA) and DSA during their diagnostic workup) were included in the study. Magnetic resonance images were retrospectively analysed by two independent neuroradiologists to determine the localisation and cause of the ICH. DSA was used as a reference standard. In seven patients (10.4%), a DSA-positive vascular aetiology was present (one aneurysm, four arteriovenous malformations, one dural arteriovenous fistula and one vasculitis). All of these cases were correctly diagnosed by both readers on MRI. In addition, MRI revealed the following probable bleeding causes in 39 of the 60 DSA-negative patients: cerebral amyloid angiopathy (17), cavernoma (9), arterial hypertension (8), haemorrhagic transformation of an ischaemic infarction (3) and malignant brain tumour with secondary ICH (2). Performing MRI with MRA proved to be an accurate diagnostic tool in detecting vascular malformations in patients with ICH. In addition, MRI provided valuable information regarding DSA-negative ICH causes, and thus had a high diagnostic yield in ICH patients. (orig.)

  11. Effect of Donepezil on Wernicke Aphasia After Bilateral Middle Cerebral Artery Infarction: Subtraction Analysis of Brain F-18 Fluorodeoxyglucose Positron Emission Tomographic Images.

    Science.gov (United States)

    Yoon, Seo Yeon; Kim, Je-Kyung; An, Young-Sil; Kim, Yong Wook

    2015-01-01

    Aphasia is one of the most common neurologic deficits occurring after stroke. Although the speech-language therapy is a mainstream option for poststroke aphasia, pharmacotherapy is recently being tried to modulate different neurotransmitter systems. However, the efficacy of those treatments is still controversial. We present a case of a 53-year-old female patient with Wernicke aphasia, after the old infarction in the territory of left middle cerebral artery for 8 years and the recent infarction in the right middle cerebral artery for 4 months. On the initial evaluation, the Aphasia Quotient in Korean version of the Western Aphasia Battery was 25.6 of 100. Baseline brain F-18 fluorodeoxyglucose positron emission tomographic images demonstrated a decreased cerebral metabolism in the left temporoparietal area and right temporal lobe. Donepezil hydrochloride, a reversible acetylcholinesterase inhibitor, was orally administered 5 mg/d for 6 weeks after the initial evaluation and was increased to 10 mg/d for the following 6 weeks. After the donepezil treatment, the patient showed improvement in language function, scoring 51.0 of 100 on Aphasia Quotient. A subtraction analysis of the brain F-18 fluorodeoxyglucose positron emission tomographic images after donepezil medication demonstrated increased uptake in both middle temporal gyri, extended to the occipital area and the left cerebellum. Thus, we suggest that donepezil can be an effective therapeutic choice for the treatment of Wernicke aphasia.

  12. Digital subtraction angiography in ischemic cerebrovascular accidents

    Energy Technology Data Exchange (ETDEWEB)

    Manelfe, C.; Bonafe, A.; Ducos de Lahitte, M.; Rascol, A.; Prere, J.; Guiraud, B.; Marc-Vergnes, J.P. (Hopital Purpan, 31 - Toulouse (France))

    1983-12-29

    Recent advances in computer and radiological technology have permitted reassessment of intravenous angiography in the evaluation of cerebrovascular disorders. Although digital subtraction angiography is a relatively new technique, it has rapidly gained a widespread acceptance. It has extended the use of angiography to outpatients and to people in whom conventional angiography is contraindicated. This reliable, safe, and relatively noninvasive technique offers the user two benefits: real-time subtraction and enhanced image quality. The system allows angiographic evaluation of the extracranial and intracranial vessels by means of intravenous injection of contrast material. Extracranial studies clearly demonstrate stenoses and occlusions of the major cervicocephalic arteries. Intracranial studies usually detect major cerebrovascular occlusions and provide insight into the collateral flow patterns. Intravenous digital subtraction angiography permits accurate assessment of cervicocephalic vessels after surgical repair. Although intravenous digital subtraction angiography obviates the need for conventional angiography in many cases, movements from the patients, or superimposition of vascular structures can substantially degrade the quality of the images. Digital subtraction angiography with intra-arterial injection of contrast medium will be contemplated in patients with poor intravenous digital subtraction angiography studies prior to surgery.

  13. Digital subtraction angiography in ischemic cerebrovascular accidents

    International Nuclear Information System (INIS)

    Manelfe, C.; Bonafe, A.; Ducos de Lahitte, M.; Rascol, A.; Prere, J.; Guiraud, B.; Marc-Vergnes, J.P.

    1983-01-01

    Recent advances in computer and radiological technology have permitted reassessment of intravenous angiography in the evaluation of cerebrovascular disorders. Although digital subtraction angiography is a relatively new technique, it has rapidly gained a widespread acceptance. It has extended the use of angiography to outpatients and to people in whom conventional angiography is contraindicated. This reliable, safe, and relatively noninvasive technique offers the user two benefits: real-time subtraction and enhanced image quality. The system allows angiographic evaluation of the extracranial and intracranial vessels by means of intravenous injection of contrast material. Extracranial studies clearly demonstrate stenoses and occlusions of the major cervicocephalic arteries. Intracranial studies usually detect major cerebrovascular occlusions and provide insight into the collateral flow patterns. Intravenous digital subtraction angiography permits accurate assessment of cervicocephalic vessels after surgical repair. Although intravenous digital subtraction angiography obviates the need for conventional angiography in many cases, movements from the patients, or superimposition of vascular structures can substantially degrade the quality of the images. Digital subtraction angiography with intra-arterial injection of contrast medium will be contemplated in patients with poor intravenous digital subtraction angiography studies prior to surgery [fr

  14. COMPARISON OF BACKGROUND SUBTRACTION, SOBEL, ADAPTIVE MOTION DETECTION, FRAME DIFFERENCES, AND ACCUMULATIVE DIFFERENCES IMAGES ON MOTION DETECTION

    Directory of Open Access Journals (Sweden)

    Dara Incam Ramadhan

    2018-02-01

    Full Text Available Nowadays, digital image processing is not only used to recognize motionless objects, but also used to recognize motions objects on video. One use of moving object recognition on video is to detect motion, which implementation can be used on security cameras. Various methods used to detect motion have been developed so that in this research compared some motion detection methods, namely Background Substraction, Adaptive Motion Detection, Sobel, Frame Differences and Accumulative Differences Images (ADI. Each method has a different level of accuracy. In the background substraction method, the result obtained 86.1% accuracy in the room and 88.3% outdoors. In the sobel method the result of motion detection depends on the lighting conditions of the room being supervised. When the room is in bright condition, the accuracy of the system decreases and when the room is dark, the accuracy of the system increases with an accuracy of 80%. In the adaptive motion detection method, motion can be detected with a condition in camera visibility there is no object that is easy to move. In the frame difference method, testing on RBG image using average computation with threshold of 35 gives the best value. In the ADI method, the result of accuracy in motion detection reached 95.12%.

  15. A Wide-Field Fluorescence Microscope Extension for Ultrafast Screening of One-Bead One-Compound Libraries Using a Spectral Image Subtraction Approach.

    Science.gov (United States)

    Heusermann, Wolf; Ludin, Beat; Pham, Nhan T; Auer, Manfred; Weidemann, Thomas; Hintersteiner, Martin

    2016-05-09

    The increasing involvement of academic institutions and biotech companies in drug discovery calls for cost-effective methods to identify new bioactive molecules. Affinity-based on-bead screening of combinatorial one-bead one-compound libraries combines a split-mix synthesis design with a simple protein binding assay operating directly at the bead matrix. However, one bottleneck for academic scale on-bead screening is the unavailability of a cheap, automated, and robust screening platform that still provides a quantitative signal related to the amount of target protein binding to individual beads for hit bead ranking. Wide-field fluorescence microscopy has long been considered unsuitable due to significant broad spectrum autofluorescence of the library beads in conjunction with low detection sensitivity. Herein, we demonstrate how such a standard microscope equipped with LED-based excitation and a modern CMOS camera can be successfully used for selecting hit beads. We show that the autofluorescence issue can be overcome by an optical image subtraction approach that yields excellent signal-to-noise ratios for the detection of bead-associated target proteins. A polymer capillary attached to a semiautomated bead-picking device allows the operator to efficiently isolate individual hit beads in less than 20 s. The system can be used for ultrafast screening of >200,000 bead-bound compounds in 1.5 h, thereby making high-throughput screening accessible to a wider group within the scientific community.

  16. A Theoretical and Experimental Study of the Subtraction of Two Scintigraphic Images - As Applied to Visualization of the Pancreas; Etude Theorique et Experimentale de la Soustraction de Deux Images Scintigraphiques

    Energy Technology Data Exchange (ETDEWEB)

    Desgrez, A.; Razafindramamba, V.; Saint-Laurent, J. de; Kellershohn, C. [CEA, Service Hospitalier Frederic Joliot, Orsay (France)

    1969-05-15

    Some scintigraphic studies are limited because the tissue being depicted is not selective with respect to the radioactive product available. For example, the radioactivity of the circulating blood interferes with mercury scanning of bucco-pharyngeal tumours. Scintigraphy of the pancreas is likewise impeded by localization of selenomethionine in the liver. Similarly, certain types of liver incorporation impair the visualization of insufficiency in the right kidney. One solution to this problem is to use two different labelled compounds to produce two images and then subtract one from the other so as to separate out the tissue to be depicted. The paper deals with the various problems involved in such subtraction. For example, exact spatial coincidence ofthedata to be subtracted can be ensured only by simultaneous recording of the two images; aconsecutive recording, even if it is fast, may be detrimental. The operation often consists in a double technique: suppression of the unwanted tissue by subtraction and amplification of the contrast between the tissue under investigation and residual background noise. These two operations, subtraction and amplification, relate to variable magnitudes; the resolution of the final image is thus a function of certain statistical parameters, which are also discussed. In studies carried out on the pancreas, attention is paid to the respective advantages and conditions of spectrometric separation of the various products which can be used for subtraction; the value of labelled rose bengal, which can also be used for eliminating certain intestinal loops, is stressed. A description is given of two types of apparatus which can be used in making the subtraction. The first and cheaper device involves storing the data obtained on four-track magnetic tape; the second and more rapid method utilizes the memory of a 4096-channel analyser. With both of these devices it is possible to make several subtractions during a single examination and the

  17. Tomosynthesis applied to digital subtraction angiography

    International Nuclear Information System (INIS)

    Kruger, R.A.; Sedaghati, M.; Roy, D.G.; Liu, P.; Nelson, J.A.; Kubal, W.; Del Rio, P.

    1984-01-01

    This extension of the author's previous work on tomographic digital subtraction angiography (DSA) describes the theory of tomosynthetic DSA image reconstruction techniques. In addition to developing the resolution limits resulting from x-ray exposure length and image intensifier field curvature, the authors describe one method of image formation and show tomosynthetic DSA images of animal and human anatomy. Methods for improving the present technique are discussed

  18. Cerebral bone subtraction CT angiography using 80 kVp and sinogram-affirmed iterative reconstruction: contrast medium and radiation dose reduction with improvement of image quality

    Energy Technology Data Exchange (ETDEWEB)

    Nagayama, Yasunori [Kumamoto City Hospital, Department of Radiology, Kumamoto (Japan); Kumamoto University, Department of Diagnostic Radiology, Chuo-ku, Kumamoto (Japan); Nakaura, Takeshi; Oda, Seitaro; Kidoh, Masafumi; Utsunomiya, Daisuke; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Chuo-ku, Kumamoto (Japan); Tsuji, Akinori; Urata, Joji; Furusawa, Mitsuhiro; Yuki, Hideaki; Hirarta, Kenichiro [Kumamoto City Hospital, Department of Radiology, Kumamoto (Japan)

    2017-02-15

    The purpose of this study was to evaluate the feasibility of a contrast medium (CM), radiation dose reduction protocol for cerebral bone-subtraction CT angiography (BSCTA) using 80-kVp and sinogram-affirmed iterative reconstruction (SAFIRE). Seventy-five patients who had undergone BSCTA under the 120- (n = 37) or the 80-kVp protocol (n = 38) were included. CM was 370 mgI/kg for the 120-kVp and 296 mgI/kg for the 80-kVp protocol; the 120- and the 80-kVp images were reconstructed with filtered back-projection (FBP) and SAFIRE, respectively. We compared effective dose (ED), CT attenuation, image noise, and contrast-to-noise ratio (CNR) of two protocols. We also scored arterial contrast, sharpness, depiction of small arteries, visibility near skull base/clip, and overall image quality on a four-point scale. ED was 62% lower at 80- than 120-kVp (0.59 ± 0.06 vs 1.56 ± 0.13 mSv, p < 0.01). CT attenuation of the internal carotid artery (ICA) and middle cerebral artery (MCA) was significantly higher on 80- than 120-kVp (ICA: 557.4 ± 105.7 vs 370.0 ± 59.3 Hounsfield units (HU), p < 0.01; MCA: 551.9 ± 107.9 vs 364.6 ± 62.2 HU, p < 0.01). The CNR was also significantly higher on 80- than 120-kVp (ICA: 46.2 ± 10.2 vs 36.9 ± 7.6, p < 0.01; MCA: 45.7 ± 10.0 vs 35.7 ± 9.0, p < 0.01). Visibility near skull base and clip was not significantly different (p = 0.45). The other subjective scores were higher with the 80- than the 120-kVp protocol (p < 0.05). The 80-kVp acquisition with SAFIRE yields better image quality for BSCTA and substantial reduction in the radiation and CM dose compared to the 120-kVp with FBP protocol. (orig.)

  19. Temporal subtraction in chest radiography: Automated assessment of registration accuracy

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Doshi, Devang J.; Engelmann, Roger; Croteau, Charles L.; MacMahon, Heber

    2006-01-01

    Radiologists routinely compare multiple chest radiographs acquired from the same patient over time to more completely understand changes in anatomy and pathology. While such comparisons are achieved conventionally through a side-by-side display of images, image registration techniques have been developed to combine information from two separate radiographic images through construction of a 'temporal subtraction image'. Although temporal subtraction images provide a powerful mechanism for the enhanced visualization of subtle change, errors in the clinical evaluation of these images may arise from misregistration artifacts that can mimic or obscure pathologic change. We have developed a computerized method for the automated assessment of registration accuracy as demonstrated in temporal subtraction images created from radiographic chest image pairs. The registration accuracy of 150 temporal subtraction images constructed from the computed radiography images of 72 patients was rated manually using a five-point scale ranging from '5-excellent' to '1-poor'; ratings of 3, 4, or 5 reflected clinically acceptable subtraction images, and ratings of 1 or 2 reflected clinically unacceptable images. Gray-level histogram-based features and texture measures are computed at multiple spatial scales within a 'lung mask' region that encompasses both lungs in the temporal subtraction images. A subset of these features is merged through a linear discriminant classifier. With a leave-one-out-by-patient training/testing paradigm, the automated method attained an A z value of 0.92 in distinguishing between temporal subtraction images that demonstrated clinically acceptable and clinically unacceptable registration accuracy. A second linear discriminant classifier yielded an A z value of 0.82 based on a feature subset selected from an independent database of digitized film images. These methods are expected to advance the clinical utility of temporal subtraction images for chest

  20. A NEW CEPHEID DISTANCE TO THE GIANT SPIRAL M101 BASED ON IMAGE SUBTRACTION OF HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS OBSERVATIONS

    International Nuclear Information System (INIS)

    Shappee, Benjamin J.; Stanek, K. Z.

    2011-01-01

    We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival Hubble Space Telescope (HST)/Advanced Camera for Surveys V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal differential light curves from HST data. We discovered 827 Cepheids with periods between 3 and 80 days, the largest extragalactic sample of Cepheids observed with HST by a factor of two. With this large Cepheid sample, we find that the relative distance of M101 from the Large Magellanic Cloud is Δμ LMC = 10.63 ± 0.04 (random) ± 0.06 (systematic) mag. If we use the geometrically determined maser distance to NGC 4258 as our distance anchor, the distance modulus of M101 is μ 0 = 29.04 ± 0.05 (random) ± 0.18 (systematic) mag or D = 6.4 ± 0.2 (random) ± 0.5 (systematic) Mpc. The uncertainty is dominated by the maser distance estimate (±0.15 mag), which should improve over the next few years. We determine a steep metallicity dependence, γ, for our Cepheid sample through two methods, yielding γ = -0.80 ± 0.21 (random) ± 0.06 (systematic) mag dex -1 and γ = -0.72 +0.22 -0.25 (random) ± 0.06 (systematic) mag dex -1 . We see marginal evidence for variations in the Wesenheit period-luminosity relation slope as a function of deprojected galactocentric radius. We also use the tip of the red giant branch method to independently determine the distance modulus to M101 of μ 0 = 29.05 ± 0.06 (random) ± 0.12 (systematic) mag.

  1. Evaluation of sacroiliitis: contrast-enhanced MRI with subtraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Algin, Oktay; Gokalp, Gokhan; Baran, Bulent; Ocakoglu, Gokhan; Yazici, Zeynep [Uludag University, Medical Faculty, Department of Radiology, Gorukle, Bursa (Turkey)

    2009-10-15

    The purpose of the study was to investigate the diagnostic value of contrast-enhanced MRI using the subtraction technique in the detection of active sacroiliitis. Magnetic resonance imaging was performed in 8 asymptomatic volunteers and 50 patients with clinically suspected active sacroiliitis. On precontrast MR images, T1-weighted spin-echo images with and without fat saturation (T1WFS and T1W), STIR and 3D-FLASH images with fat saturation were obtained in the semicoronal plane using a 1.5 Tesla imager. Postcontrast MRI was performed using the same T1WFS sequence as before contrast injection for all volunteers and patients. Postcontrast images were subtracted from fat-suppressed precontrast images. Enhancement within the joint space and bone marrow was considered to demonstrate active sacroiliitis. In 50 patients (100 sacroiliac joints [SIJs]), 40 (76 SIJs) were considered to have active sacroiliitis based on MR images. Bone marrow edema was present in 33 patients (62 SIJs) on STIR images. Routine MRI allowed identification of contrast enhancement in SIJs on postcontrast T1WFS images in 31 patients (49 SIJs). Contrast enhancement was observed in 40 patients (76 SIJs) who were examined by MRI using the subtraction technique. Contrast enhancement was significantly more conspicuous on subtraction images than on non-subtracted postcontrast T1WFS images (Mann-Whitney U test, p<0.001). Contrast-enhanced MRI with subtraction technique may be useful for early detection of active sacroiliitis. (orig.)

  2. Development of Shimadzu digital subtraction system

    International Nuclear Information System (INIS)

    Nishioka, Hiroyuki; Shibata, Koichi; Shimizu, Yasumitsu; Shibata, Kenji; Wani, Hidenobu

    1985-01-01

    Shimadzu has recently developed a digital subtraction system. It can perform intra-arterial digital subtraction angiography (DSA) using low concentration of contrast medium, or can visualize arteries with intravenuous injection. It can extremely reduce patient's pain in angiography. Image quality of DSA has been much improved by the development of high quality image amplifiers, improvement of signal-to-noise ratio of the x-ray television unit and the development of digital disk recorders. The peak-hold subtraction method that is now under clinical study presents images of blood vessels as the trace of the flow of contrast medium. The maximum-hold memory where the maximum value of the brightness in some period is stored for every picture element is subtracted from the minimum-hold memory where the minimum value is stored, and thus images of blood vessels can be obtained. Hardware of this method is rather simple and it is expected that the amount of contrast medium may be reduced or x-ray dose of the patient may be decreased. (author)

  3. Exercise intravenous digital subtraction angiography

    International Nuclear Information System (INIS)

    Yiannikas, J.

    1986-01-01

    Attempts to use exercise ventriculography have been made, not only to give diagnostic and perhaps even prognostic information in patients with coronary artery disease, but also in patients with valvular heart disease both before and after surgical intervention. Clearly an accurate method of assessing ventricular function under conditions of stress in various cardiac diseases would provide important information that would help in patient management. Exercise ventriculography using gated blood pool equilibrium technetium studies are widely used, but are limited by spatial resolution and by the foreshortening affects of visualizing the left ventricular chamber in the left anterior oblique view. First pass radionuclide studies have the added advantage of being able to visualize the ventricular chamber in the anterior or even the right anterior oblique view, but are even more limited by their spatial resolution problems. Several investigations have shown that digital subtraction angiography produces left ventricular images with a spatial resolution almost identical to that of conventional contrast ventriculography, but without the inherent problems of cardiac arrhythmias, which often limit the assessment of left ventricular function. Because of its ability to accurately delineate wall motion abnormalities, the technique may provide an adequate assessment of global and regional left ventricular function after exercise. Digital subtraction angiography may identify ischemic wall motion abnormalities produced by exercise in patients who already had significant permanent left ventricular damage from myocardial infarction

  4. Role of quantitative chemical shift magnetic resonance imaging and chemical shift subtraction technique in discriminating adenomatous from non adenomatous adrenal solid lesions

    Directory of Open Access Journals (Sweden)

    Ahmed H. Afifi

    2017-03-01

    Conclusion: The signal intensity index and adrenal to spleen ratio are the most reliable quantitative chemical shift MRI methods in differentiation of adrenal adenomas from other non-adenomatous adrenal solid lesions. Chemical shift subtraction MRI is a recent technique that gives highly confident discrimination between two categories of pathology without using of any reference organ.

  5. Digital subtraction cardiopulmonary angiography using FCR (Fuji computed radiography)

    International Nuclear Information System (INIS)

    Tanimura, Shigeo; Tomoyasu, Hiroshi; Banba, Jiro; Masaki, Mikio; Kanno, Yukio; Abe, Kazuo

    1987-01-01

    Digital subtraction cardiopulmonary angiography using FCR was performed on 46 patients including lung cancer, mediastinal tumor, giant bullous formation and others. The images of digital subtraction for pulmonary artery, pulmonary vein and thoracic aorta were studied by comparing to the conventional pulmonary angiogram. Good images of pulmonary artery due to digital subtraction were obtained in 80 % of the 45 cases. This method needed only half volume of contrast media compared to the conventional for obtaining good images and thus reduced side effect. Therefore this method seems to be an usefull pre-operative examination in various chest diseases, especially in case of lung cancer. (author)

  6. Digital subtraction angiography in patients with central vertigo

    International Nuclear Information System (INIS)

    Inamori, Toru; Takayasu, Yukio; Umetani, Yoshio; Taruoka, Akinori.

    1985-01-01

    Digital subtraction angiography (DSA) is a recently developed non-invasive intravenous angiography which has become possible through real time digital subtraction of x-ray transmission data from an image intensifier and television system. The output signals of the image intensifier-television camera system are digitized by an analog-digital converter. The digital information, 512x512 pixels and 9 bits deep, is fed into the image processing assembly after logarithmic amplification, where 2-8 frames are added and subtracted from mask images for the final digital images. Intravenous digital subtraction angiography was performed in 21 patients with intractable dizzy spells of central origin resistant to treatment. These patients showed some signs of CNS disturbance, although there were no significant findings on CT scans. Surprisingly, findings were abnormal in 14 of 21 patients (66.7%). DSA is, therefore, considered to be an important aid in the diagnosis of vertigo of the central type. (J.P.N.)

  7. Digital contrast subtraction radiography for proximal caries diagnosis

    International Nuclear Information System (INIS)

    Kang, Byung Cheol; Yoon, Suk Ja

    2002-01-01

    To determine whether subtraction images utilizing contrast media can improve the diagnostic performance of proximal caries diagnosis compared to conventional periapical radiographic images. Thirty-six teeth with 57 proximal surfaces were radiographied using a size no.2 RVG-ui sensor (Trophy Radiology, Marne-la-Vallee, France). The teeth immersed in water-soluble contrast media and subtraction images were taken. Each tooth was then sectioned for histologic examination. The digital radiographic images and subtraction images were examined and interpreted by three dentists for proximal caries. The results of the proximal caries diagnosis were then verified with the results of the histologic examination. The proximal caries sensitivity using digital subtraction radiography was significantly higher than simply examining a single digital radiograph. The sensitivity of the proximal dentinal carious lesion when analyzed with the subtraction radiograph and the radiograph together was higher than with the subtraction radiograph or the radiograph alone. The use of subtraction radiography with contrast media may be useful for detecting proximal dentinal carious lesions.

  8. Automating dipole subtraction

    International Nuclear Information System (INIS)

    Hasegawa, K.; Moch, S.; Uwer, P.

    2008-07-01

    We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg→t anti tggg. (orig.)

  9. Automating dipole subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Uwer, P. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Theoretische Teilchenphysik

    2008-07-15

    We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg{yields}t anti tggg. (orig.)

  10. Colourful FKS subtraction

    CERN Document Server

    Frixione, Stefano

    2011-01-01

    I formulate in a colour-friendly way the FKS method for the computation of QCD cross sections at the next-to-leading order accuracy. This is achieved through the definition of subtraction terms for squared matrix elements, constructed with single colour-dressed or pairs of colour-ordered amplitudes. The latter approach relies on the use of colour flows, is exact to all orders in $N$, and is thus particularly suited to being organized as a systematic expansion in 1/N.

  11. Digital subtraction cerebral angiography by intraarterial injection: comparison with conventional angiography

    International Nuclear Information System (INIS)

    Brant-Zawadzki, M.; Gould, R.; Norman, D.; Newton, T.H.; Lane, B.

    1983-01-01

    For 4 months, a prototype digital subtraction system was used to obtain images of the cerebral vasculature after intraarterial contrast injections. In 12 instances, the intraarterial injections were recorded with both a digital subtraction unit and conventional direct magnification film-screen system. The digital subtraction and conventional film subtraction images were compared and graded for quality and information content by three skilled observers. In addition, quantitative measurements of contrast-detail performance and spatial resolution were obtained on both the digital system and the screen-film imaging chain. In a clinical setting, both the digital subtraction and conventional film-screen systems provided similar quality images and angiographic information. Contrast-detail curves demonstrated that digital subtraction angiography outperformed conventional film technique for low-contrast objects. Digital subtraction angiography also reduced the time required to obtain the angiogram, markedly reduced film cost, and lowered the contrast agent burden

  12. Hardware Implementation of a Bilateral Subtraction Filter

    Science.gov (United States)

    Huertas, Andres; Watson, Robert; Villalpando, Carlos; Goldberg, Steven

    2009-01-01

    A bilateral subtraction filter has been implemented as a hardware module in the form of a field-programmable gate array (FPGA). In general, a bilateral subtraction filter is a key subsystem of a high-quality stereoscopic machine vision system that utilizes images that are large and/or dense. Bilateral subtraction filters have been implemented in software on general-purpose computers, but the processing speeds attainable in this way even on computers containing the fastest processors are insufficient for real-time applications. The present FPGA bilateral subtraction filter is intended to accelerate processing to real-time speed and to be a prototype of a link in a stereoscopic-machine- vision processing chain, now under development, that would process large and/or dense images in real time and would be implemented in an FPGA. In terms that are necessarily oversimplified for the sake of brevity, a bilateral subtraction filter is a smoothing, edge-preserving filter for suppressing low-frequency noise. The filter operation amounts to replacing the value for each pixel with a weighted average of the values of that pixel and the neighboring pixels in a predefined neighborhood or window (e.g., a 9 9 window). The filter weights depend partly on pixel values and partly on the window size. The present FPGA implementation of a bilateral subtraction filter utilizes a 9 9 window. This implementation was designed to take advantage of the ability to do many of the component computations in parallel pipelines to enable processing of image data at the rate at which they are generated. The filter can be considered to be divided into the following parts (see figure): a) An image pixel pipeline with a 9 9- pixel window generator, b) An array of processing elements; c) An adder tree; d) A smoothing-and-delaying unit; and e) A subtraction unit. After each 9 9 window is created, the affected pixel data are fed to the processing elements. Each processing element is fed the pixel value for

  13. Breast MRI at very short TE (minTE). Image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

    International Nuclear Information System (INIS)

    Wenkel, Evelyn; Janka, Rolf; Kaemmerer, Nadine; Uder, Michael; Hammon, Matthias; Brand, Michael; Hartmann, Arndt

    2017-01-01

    The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50%. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. With minTE sequences, no lesion was rated with ''definitely want to see nTE sequences for final assessment''. The difference of the longitudinal and transverse diameter did not differ significantly (p>0.05). With minTE, lesions and skin were rated to be significantly more blurry (p<0.01 for lesions and p<0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences.

  14. Breast MRI at very short TE (minTE). Image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Wenkel, Evelyn; Janka, Rolf; Kaemmerer, Nadine; Uder, Michael; Hammon, Matthias; Brand, Michael [Univ. Hospital Erlangen (Germany). Dept. of Radiology; Geppert, Christian [Siemens Healthcare GmbH, Erlangen (Germany); Hartmann, Arndt [Univ. Hospital Erlangen (Germany). Dept. of Pathology

    2017-02-15

    The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50%. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. With minTE sequences, no lesion was rated with ''definitely want to see nTE sequences for final assessment''. The difference of the longitudinal and transverse diameter did not differ significantly (p>0.05). With minTE, lesions and skin were rated to be significantly more blurry (p<0.01 for lesions and p<0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences.

  15. Motion subtraction of the larynx using digital radiography

    International Nuclear Information System (INIS)

    Kumakawa, Kohzoh; Miyakawa, Kouichi

    1990-01-01

    The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. The authors first used the DR system for time subtraction of the larynx during inspiration and phonation. The images are acquired by means of frontal tomography of the larynx using the imaging plate during inspiration and phonation separately, and stored into the memory of the DR system. The thickness of the slices is 5.0 mm. Time subtraction between the mask image during inspiration and the live image during phonation is performed using digital processing on CRT. Superimposing the two images at the upper trachea and the thyroid cartilage of the same depth, makes it possible to measure movement of the vocal cord and false vocal cord quantitatively in three dimensions. The authors named this time subtraction as motion subtraction of the larynx. This motion subtraction image can be obtained by on-line digital processing without complicated development technique, but has so high spatial resolution. This image processing seems to be useful in functional radiographic analysis of laryngeal diseases. (author)

  16. Background subtraction theory and practice

    CERN Document Server

    Elgammal, Ahmed

    2014-01-01

    Background subtraction is a widely used concept for detection of moving objects in videos. In the last two decades there has been a lot of development in designing algorithms for background subtraction, as well as wide use of these algorithms in various important applications, such as visual surveillance, sports video analysis, motion capture, etc. Various statistical approaches have been proposed to model scene backgrounds. The concept of background subtraction also has been extended to detect objects from videos captured from moving cameras. This book reviews the concept and practice of back

  17. Physical principles of cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Buonocore, E.; Pavlicek, W.

    1986-01-01

    Advances in the applications of computers with standard radiologic equipment have resulted in the development of electronic, or so-called ''film-less'' imaging. This technique, discussed by the authors, has become of particular value in the visualization of the central vascular system and has become known as digital subtraction angiography (DSA). Commercial products have become increasingly available and are capable of converting T.V. signals, obtained by conventional fluorography, to a computed array of digital values. Addition, subtraction, and averaging of this data, result in images with adequate signal-to-noise ratios that achieve detection of low concentrations of contrast media not possible with conventional screen film techniques. Computer subtraction of unnecessary background information improves the conspicuity of the opacified vessels to permit detection of vascular structures containing a concentration of no more than 1-3 percent of contrast media. This improved visualization is possible even with intravenous peripheral injections or reduced amounts of contrast media given intraarterially. With either method of contrast media administration, DSDA has become an excellent means of anatomic demonstration of the heart and great vessels with decreased morbidity and at lower cost

  18. Digital subtraction radiography in the study of moving laryngeal structures

    International Nuclear Information System (INIS)

    Perri, G.; Falaschi, F.; Pieri, L.; Esposito, S.; Ursino, F.

    1988-01-01

    Digital subtraction radiography (DSR) was applied to the study of the larynx in 11 healthy subjects and 15 pathological cases. The method, consisting in the subtraction of images obtained at rest and during phonation or respiratory phases, allowed a clear definition of the normal moving structures - i.e. vocal cords, false cords, pyriform sinuses, thyroid cartilage. Moreover, several pathological conditions could be demonstrated. DSR asserts thus itself as a suitable technique in the functional evaluation of glottis

  19. Arthrography of painful hips following arthroplasty: Digital versus plain film subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Walker, C W; FitzRandolph, R L; Dalrymple, G V [Arkansas Univ. for Medical Sciences, Little Rock, AR (USA). Dept. of Radiology John McClellan Memorial Veterans Hospital, Little Rock, AR (USA); Collins, D N [Arkansas Univ. for Medical Sciences, Little Rock, AR (USA). Dept. of Orthopedics John McClellan Memorial Veterans Hospital, Little Rock, AR (USA)

    1991-08-01

    Digital and manual subtraction images obtained during the arthrographic evaluation of 78 painful hip prostheses were reviewed retrospectively. Revision arthroplasty was performed in 53 of these cases, and the arthrographic and surgical findings were correlated. The digital and manual subtraction images were evaluated without knowledge of the surgical results using established criteria for component loosening. The difference between detection of femoral component loosening on digital as opposed to manual subtraction images was statistically significant (P < 0.05). This study demonstrates that digital subtraction improves the evaluation of femoral component loosening in painful hip prostheses. (orig./GDG).

  20. Digital subtraction radiographic evaluation of the standardize periapical intraoral radiographs

    International Nuclear Information System (INIS)

    Cho, Bong Hae; Nah, Kyung Soo

    1993-01-01

    The geometrically standardized intraoral radiographs using 5 occlusal registration material were taken serially from immediate, 1 day, 2, 4, 8, 12 and 16 weeks after making the bite blocks. The qualities of those subtracted images were evaluated to check the degree of reproducibility of each impression material. The results were as follows: 1. The standard deviations of the grey scales of the overall subtracted images were 4.9 for Exaflex, 7.2 for Pattern resin, 9.0 for Tooth Shade Acrylic, 12.2 for XCP only, 14.8 for Impregum. 2. The standard deviation of the grey scales of the overall subtracted images were grossly related to those of the localized horizontal line of interest. 3. Exaflex which showed the best subtracted image quality had 15 cases of straight, 14 cases of wave, 1 case of canyon shape. Impregum which showed the worst subtracted image quality had 4 cases of straight, 8 cases of wave, 18 cases of canyon shape respectively.

  1. Subtractive Structural Modification of Morpho Butterfly Wings.

    Science.gov (United States)

    Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen

    2015-11-11

    Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    International Nuclear Information System (INIS)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul

    2000-01-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.=20

  3. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2000-06-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.

  4. ECG-gating in non-cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Gattoni, F.; Baldini, V.; Cairo, F.

    1987-01-01

    This paper reports the results of the ECG-gating in non-cardiac digital subtraction angiography (DSA). One hundred and fifteen patients underwent DSA (126 examinations); ECG-gating was applied in 66/126 examinations: images recorded at 70% of R wave were subtracted. Artifacts produced by vascular movements were evaluated in all patients: only 40 examinations, carried out whithout ECG-gating, showed vascular artifacts. The major advantage of the ECG-gated DSA is the more efficent subtraction because of the better images superimposition: therefore, ECG-gating can be clinically helpful. On the contrary, it could be a problem in arrhytmic or bradycardic patients. ECG-gating is helpful in DSA imaging of the thoracic and abdominal aorta and of the cervical and renal arteries. In the examinations of peripheral vessels of the limbs it is not so efficent as in the trunk or in the neck

  5. Clinical application of digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Morimoto, Tadashi; Kaku, Suiei; Morikawa, Eiji

    1984-01-01

    Intra-arterial digital subtraction angiography (IA-DSA) by the direct puncture of the carotid artery was described with special reference to its techniques, and cases were presented. This method was safe and painless and could be performed repeatedly. Cerebral angiographic images obtained by this method were either superior or fully compatible to the conventional cerebral angiography. It is therefore of great diagnostic value and can replace the conventional method. Furthermore, since the pretreatment is unnecessary and the time required is short, IA-DSA can be used as an adjuvant method for emergency diagnosis. (Namekawa, K)

  6. Intraarterial digital subtraction angiography in neuroradiology

    International Nuclear Information System (INIS)

    Zeumer, H.

    1987-01-01

    Neuroradiology always could make best use of subtraction methods, due to the relative immobility and constant shape of the skull. Arterial DSA now has extended the potential uses while reducing the patient's radiation exposure, the contrast medium dosage and osmolarity. The considerable cut-back in time required for invasive examination has reduced the risk of diagnostic and therapeutic measures. The advantages consisting of immediate image display with high contrast resolution in most of the diagnostic tasks counterbalance the disadvantage of low focal resolution of the DSA in neuroradiology. Interventional neuroradiology today cannot do without i.a. DSA. (orig.) [de

  7. A study on the geometric correction for the digital subtraction radiograph

    International Nuclear Information System (INIS)

    Lim, Suk Young; Koh, Kwang Joon

    2001-01-01

    To develop a new subtraction program for registering digital images based on the correspondence of anatomic structures. The digital periapical images were obtained by Digora system with Rinn XCP equipment after translation of 1-16 mm, and rotation of 2-20 at the premolar and molar areas of the human dried mandible. The new subtraction program, NIH Image program and Emago/Advanced program were compared by the peak-signal -to noise ratio (PSNR). The new subtraction program was superior to NIH Images program and Emago/Advanced program up to 16 mm translation and horizontal angulation up to 4. The new subtraction program can be used for subtracting digital periapical images

  8. Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

    Science.gov (United States)

    Bahr, Christopher J.; Horne, William C.

    2015-01-01

    An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

  9. Color Addition and Subtraction Apps

    Science.gov (United States)

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  10. Digital subtraction angiography in traumatology

    International Nuclear Information System (INIS)

    Steudel, A.; Harder, T.; Lackner, K.; Schneider, B.; Orellano, L.; Bonn Univ.; Bonn Univ.

    1986-01-01

    The methods, indications and results of digital subtraction angiography in traumatology are presented, based on 56 examinations. The different use of intravenous or intraarterial DSA will be discussed with respect to expanding and localisation of traumatic vascular injury. DSA is recommended as the method of choice for follow-up after vascular reconstructive procedure. (orig.) [de

  11. Hybrid intravenous digital subtraction angiography of the carotid bifurcation

    International Nuclear Information System (INIS)

    Burbank, F.H.; Enzmann, D.; Keyes, G.S.; Brody, W.R.

    1984-01-01

    A hybrid digital subtraction angiography technique and noise-reduction algorithm were used to evaluate the carotid bifurcation. Temporal, hybrid, and reduced-noise hybrid images were obtained in right and left anterior oblique projections, and both single- and multiple-frame images were created with each method. The resulting images were graded on a scale of 1 to 5 by three experienced neuroradiologists. Temporal images were preferred over hybrid images. The percentage of nondiagnostic examinations, as agreed upon by two readers, was higher for temporal alone than temporal + hybrid. In addition, also by agreement between two readers, temporal + hybrid images significantly increased the number of bifurcations seen in two views (87%) compared to temporal subtraction alone

  12. Digital subtraction angiography (DSA) of the heart and coronary arteries

    International Nuclear Information System (INIS)

    Struyven, J.J.; Delcour, C.; Brion, J.P.; Vandenbosch, G.; Claessens, J.

    1986-01-01

    Digital subtraction angiography has potential advantages over conventional radiography. The removal of background structures makes possible to visualize chambers of the heart, great vessels and coronary arteries with a lower iodine signal than with conventional cineangiography. Digital data used for imaging can been manipulated for assessment and quantitation of the ventricular fonction and the coronary circulation

  13. Analysis of the principal factors that intervene in the quantification of planar images of uniform distributions of 99mTc by the conjugate view method with background correction by simple subtraction

    International Nuclear Information System (INIS)

    Mora Araya, Luis Diego

    2013-01-01

    The activity of uniform distributions of 99m Tc was quantified by the conjugate view method. The necessary factors of calibration and transmission were calculated to realize the quantification. The dependence of the estimated number of accounts within the source region and variability of the value of the transmission factor were determined, according to the size established for the region of interest, keeping constant its geometry. The images of all acquisitions were corrected by environmental background radiation and radiation dispersed, by the dual energy window method (DEW). The impact of corrections in the image were checked, both qualitatively and quantitative. The acquisition to obtain the calibration factor was realized with the same configuration and the same conditions that were used to realize the acquisition for quantification; in which, the same volume and the same geometry were used to contain the distribution of the activity of 99m Tc. The volume and geometry of the same medium attenuator have obtained a calibration factor exactly in the same circumstances in which have quantified. The behavior of the estimation of the calibration factor of the gamma camera was analyzed, according to the decay corrections of the activity and the attenuation that are applied. The dependence of the calibration factors and transmission were analyzed, according to the region of interest used in the corresponding images to estimate their values. The behavior of the estimation of the activity was determined, according to all possible combinations of the factors studied that have intervened in the quantification algorithm of conjugate view, namely, the size of the region of interest corresponding to the source region, the transmission factor , the calibration factor and background correction by simple subtraction. The results obtained of the estimates of the activity were compared. A tendency is established, indicating which have been combinations of the studied factors that

  14. The digital subtraction technique in lateral urethrocystography. Die laterale Urethrozystographie in digitaler Subtraktionstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K. (Radiologische Abt., Caritas-Krankenhaus, Bad Mergentheim (Germany)); Peterseim, H. (Frauenklinik, Caritas-Krankenhaus, Bad Mergentheim (Germany)); Grehn, S. (Radiologische Abt., Caritas-Krankenhaus, Bad Mergentheim (Germany))

    1994-09-01

    The first application of the digital subtraction technique to lateral urethrocystography is described. This methodology facilitates gynecological-urological operations by providing reliable investigation results and an unambiguous image interpretation. Methods and first experiences with the digital subtraction technique in gynecological-urological diagnosis are reported. (orig.)

  15. Digital subtraction arthrography of the hips and of the shoulders

    International Nuclear Information System (INIS)

    Fink, B.K.; Schedel, J.; Fink, U.; Hansen, M.; Hilbertz, T.; Hagena, F.W.

    1991-01-01

    In a study on 60 patients, it could be shown that very good results can be achieved in the region of the shoulder joint with the use of the digital subtraction technique and of digital image intensifier radiography. A further possibility of using the digital subtraction technique for proving endoprosthesis loosenings of the hip demonstrated its importance after a short time and has become a routine method in the meantime. These two examination techniques are displayed methodologically and their clinical possibilities of use are assessed in this contribution. (orig.)

  16. Subtracted dynamic MR perfusion source images (sMRP-SI) provide collateral blood flow assessment in MCA occlusions and predict tissue fate

    International Nuclear Information System (INIS)

    Villringer, Kersten; Serrano-Sandoval, Rafael; Galinovic, Ivana; Ostwaldt, Ann-Christin; Brunecker, Peter; Fiebach, Jochen B.; Grittner, Ulrike; Schneider, Alice; Rocco, Andrea

    2016-01-01

    Collateral blood flow is accepted as a predictive factor of tissue fate in ischemic stroke. Thus, we aimed to evaluate a new method derived from MR perfusion source images to assess collateral flow in patients with ICA/MCA occlusions. A total of 132 patients of the prospective 1000+ study were examined. MR perfusion source images were assessed according to Δimg n = img n + 1 - img n - 1 using the five-grade Higashida collateral flow rating system. Higashida scores were correlated to mismatch (MM) volume, mismatch ratio, day 6 FLAIR lesion volumes and day 90 mRS. Patients with Higashida scores 3 and 4 had significantly lower admission NIHSS, smaller FLAIR day 6 lesion volumes (p < 0.001) and higher rates of better long-term outcome (mRS 0-2, p = 0.002). There was a linear trend for the association of Higashida grade 1 (p = 0.002) and 2 (p = 0.001) with unfavourable outcome (day 90 mRS 3-6), but no significant association was found for MM volume, MM ratio and day 90 mRS. Inter-rater agreement was 0.58 (95 % CI 0.43-0.73) on day 1, 0.70 (95 % CI 0.58-0.81) on day 2. sMRP-SI Higashida score offers a non-invasive collateral vessel and tissue perfusion assessment of ischemic tissue. The predictive value of Higashida rating proved superior to MM with regard to day 90 mRS. (orig.)

  17. Subtracted dynamic MR perfusion source images (sMRP-SI) provide collateral blood flow assessment in MCA occlusions and predict tissue fate

    Energy Technology Data Exchange (ETDEWEB)

    Villringer, Kersten; Serrano-Sandoval, Rafael; Galinovic, Ivana; Ostwaldt, Ann-Christin; Brunecker, Peter; Fiebach, Jochen B. [Charite-Universitaetsmedizin, Academic Neuroradiology, Center for Stroke Research (CSB), Berlin (Germany); Grittner, Ulrike [Charite, Universitaetsmedizin Berlin, Center for Stroke Research, Berlin (Germany); Charite, Department for Biostatistics and Clinical Epidemiology, Berlin (Germany); Schneider, Alice [Charite, Universitaetsmedizin Berlin, Center for Stroke Research, Berlin (Germany); Rocco, Andrea [Charite, Department of Neurology and Center for Stroke Research, Berlin (Germany)

    2016-05-15

    Collateral blood flow is accepted as a predictive factor of tissue fate in ischemic stroke. Thus, we aimed to evaluate a new method derived from MR perfusion source images to assess collateral flow in patients with ICA/MCA occlusions. A total of 132 patients of the prospective 1000+ study were examined. MR perfusion source images were assessed according to Δimg{sub n} = img{sub n} + 1 - img{sub n} - 1 using the five-grade Higashida collateral flow rating system. Higashida scores were correlated to mismatch (MM) volume, mismatch ratio, day 6 FLAIR lesion volumes and day 90 mRS. Patients with Higashida scores 3 and 4 had significantly lower admission NIHSS, smaller FLAIR day 6 lesion volumes (p < 0.001) and higher rates of better long-term outcome (mRS 0-2, p = 0.002). There was a linear trend for the association of Higashida grade 1 (p = 0.002) and 2 (p = 0.001) with unfavourable outcome (day 90 mRS 3-6), but no significant association was found for MM volume, MM ratio and day 90 mRS. Inter-rater agreement was 0.58 (95 % CI 0.43-0.73) on day 1, 0.70 (95 % CI 0.58-0.81) on day 2. sMRP-SI Higashida score offers a non-invasive collateral vessel and tissue perfusion assessment of ischemic tissue. The predictive value of Higashida rating proved superior to MM with regard to day 90 mRS. (orig.)

  18. Digital subtraction radiography in the study of the lacrimal system

    International Nuclear Information System (INIS)

    Falaschi, F.; Pieri, L.; Perri, G.; Signorini, G.; Genovese Ebert, F.

    1988-01-01

    The authors emphasize the usefulness of digital dacrycystography (DCG), as compared with various current technoques. Utilizing a radiographic unit equipped with a video-fluoroscopic system and interfaced to a digital video-processor, several digitalized images are acquired before, during and after the injection of contrast medium. Final images are obtained by subtraction of suitable pairs of source frames. Twenty-six patients affected by epiphora have been examined so far. In 21 cases digital subtraction DCG allowed an accurate visualization of the lacrimal system; in the other five patients the amount of information was acceptable. This methodology allows the assessment of both the normal anatomy of the lacrimal passages and their pathological patterns, such as obstructions, stenoses, fistulas, chronic dacrycystites, lacrimal stones. The examination is easy and quick to perform, with no discomfort for the patient. Digital subtraction DCG proves thus to be a very valuable technique thanks to its possible electronic elaboration - i.e. the subtraction and the magnification of images - to its better contrast resolution, and to the possibility it yields of dynamic studies under radioscopic control

  19. Introduction to the principles of Digital Subtraction Angiography (DSA)

    International Nuclear Information System (INIS)

    Kaplanis, P.

    1997-01-01

    Medical applications of advanced technology have rapidly become more sophisticated and more widespread. The field of diagnostic imaging is by no means an exception. There has been a number of breathtaking developments in the field of medical imaging in recent years. Today higher quality, greater clarity and more minute precision are considered not advantages but necessities. Hence new developments are concentrated in the data acquisition and image processing based on the microprocessor controlled modules interfaced with state of the art radiological imaging equipment. One such development is the subtraction of x-rays vis a computer for better visualization of blood vessels, cavities of the heart and of the coronary and pulmonary vascular system. This procedure is termed Digital Subtraction Angiography (DSA). (author)

  20. Introduction to the principles of Digital Subtraction Angiography (DSA)

    Energy Technology Data Exchange (ETDEWEB)

    Kaplanis, P [Medical Physics Department, Nicosia General Hospital, Nicosia (Cyprus)

    1998-12-31

    Medical applications of advanced technology have rapidly become more sophisticated and more widespread. The field of diagnostic imaging is by no means an exception. There has been a number of breathtaking developments in the field of medical imaging in recent years. Today higher quality, greater clarity and more minute precision are considered not advantages but necessities. Hence new developments are concentrated in the data acquisition and image processing based on the microprocessor controlled modules interfaced with state of the art radiological imaging equipment. One such development is the subtraction of x-rays vis a computer for better visualization of blood vessels, cavities of the heart and of the coronary and pulmonary vascular system. This procedure is termed Digital Subtraction Angiography (DSA). (author). 5 refs, 3 figs.

  1. Temporal subtraction of chest radiographs compensating pose differences

    Science.gov (United States)

    von Berg, Jens; Dworzak, Jalda; Klinder, Tobias; Manke, Dirk; Kreth, Adrian; Lamecker, Hans; Zachow, Stefan; Lorenz, Cristian

    2011-03-01

    Temporal subtraction techniques using 2D image registration improve the detectability of interval changes from chest radiographs. Although such methods are well known for some time they are not widely used in radiologic practice. The reason is the occurrence of strong pose differences between two acquisitions with a time interval of months to years in between. Such strong perspective differences occur in a reasonable number of cases. They cannot be compensated by available image registration methods and thus mask interval changes to be undetectable. In this paper a method is proposed to estimate a 3D pose difference by the adaptation of a 3D rib cage model to both projections. The difference between both is then compensated for, thus producing a subtraction image with virtually no change in pose. The method generally assumes that no 3D image data is available from the patient. The accuracy of pose estimation is validated with chest phantom images acquired under controlled geometric conditions. A subtle interval change simulated by a piece of plastic foam attached to the phantom becomes visible in subtraction images generated with this technique even at strong angular pose differences like an anterior-posterior inclination of 13 degrees.

  2. Bone marrow edema pattern identification in patients with lytic bone lesions using digital subtraction angiography-like bone subtraction on large-area detector computed tomography.

    Science.gov (United States)

    Gondim Teixeira, Pedro Augusto; Hossu, Gabriela; Lecocq, Sophie; Razeto, Marco; Louis, Matthias; Blum, Alain

    2014-03-01

    The objective of this study was to evaluate the performance of digital subtraction angiography (DSA)-like bone subtraction with 2 different registration methods for the identification of bone marrow edema pattern (BMEP) in patients with lytic bone lesions, using magnetic resonance imaging as the criterion standard. Fifty-five patients with a lytic bone lesion were included in this prospective study with approval from the ethics committee. All patients underwent magnetic resonance imaging and low-dose computed tomographic (CT) perfusion after signing an informed consent. Two CT volumes were used for bone subtraction, which was performed with 2 different algorithms (rigid and nonrigid). Enhancement at the nonlytic bone marrow was considered as a sign of BMEP. Two readers evaluated the images blindly. The presence of BMEP on bone-subtracted CT images was evaluated subjectively and quantitatively. Image quality was assessed. Magnetic resonance imaging was used as the criterion standard. Using a rigid registration method, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT with DSA-like bone subtraction BMEP was 77%, 100%, 100%, 68%, and 85%, respectively. The interobserver agreement was good (κ, 0.782). Image quality was better using a nonrigid registration. With this algorithm, artifacts interfered with image interpretation in only 5% of cases. However, there was a noticeable drop in sensitivity and negative predictive value when a nonrigid algorithm was used: 56% and 52%, respectively. The interobserver agreement was average with a nonrigid subtraction algorithm. Computed tomography with DSA-like bone subtraction is sensitive and highly specific for the identification of BMEP associated with lytic bone lesions. Rigid registering should be preferred, but nonrigid algorithms can be used as a second option when artifacts interfere with image interpretation.

  3. Digital subtraction angiography in the assessment of cardiovascular disease

    International Nuclear Information System (INIS)

    Harrington, D.P.; Boxt, L.M.

    1985-01-01

    Digital subtraction angiography (DSA) is a new radiographic method for evaluating the cardiovascular system. It represents another in a continuing series of computer-assisted diagnostic imaging modalities. The advantages of this technique are its relatively noninvasive nature combined with diagnostically acceptable angiographic images of a variety of cardiovascular structures. Major clinical applications of DSA include its use in imaging of localized regions of peripheral arterial disease and as a screening procedure in evaluating extracranial carotid and vertebral artery disease and renovascular hypertension. Cardiac applications of DSA include assessment of ventricular function, recognition and quantification of intracardiac shunts, visualization of coronary artery bypass grafts, and the study of complex congenital cardiac malformations. Digital subtraction angiography may also be used to evaluate intracranial aneurysms and vascular tumors

  4. 99mTc-RBC subtraction scintigraphy

    International Nuclear Information System (INIS)

    Inagaki, Syoichi; Tonami, Syuichi; Yasui, Masakazu; Kuranishi, Makoto; Sugishita, Kouki; Nakamura, Mamoru

    1994-01-01

    Sequential abdominal scintigrams with 99m Tc-labelled red blood cells (RBC) were subtracted for observing a site of gastrointestinal bleeding and calculating the bleeding rate. This method is technically very easy and can detect the site of bleeding with the minimum rate, as low as 0.2 ml/min., in a phantom experiment. In 23 cases with final diagnosis of gastrointestinal bleeding, conventional non-subtraction scintigraphy detected only 30% (7/23), but subtraction scintigraphy detected 61% (14/23). It was concluded that subtraction scintigraphy had higher sensitivity than conventional scintigraphy for early diagnosing bleeding. A combination of non-subtraction and subtraction scintigraphy is recommended to detect a site of gastrointestinal bleeding in a clinical setting. (author)

  5. The study of myocardial ischemic quality with weighted-subtraction-bull's-eye analysis

    International Nuclear Information System (INIS)

    Chen Wuduan; Tian Jiahe; Hou Qingtian

    1993-01-01

    Weighted-Subtraction-Bull's-eye analysis was studied in 33 normal subjects and 58 patients with coronary artery disease after dipyridamole 99m Tc-MIBI myocardial SPECT imaging. Two kinds of Bull's-eye were produced: (1) subtract rest from 1.2 times dipyridamole from 1.2 times rest Bull's-eye; (2) subtract dipyridamole Bull's-eye. The results showed that the weighted-subtraction-Bull's-eye could clearly displayed the location and puality of ischemic myocardium. And also 74% segments showed so called combined ischemic i.e the blood perfusion reduced, increased and sustained simultaneously after dipyridamole. Therefore weighted-subtraction-Bull's-eye analysis had provided a new method for determination of the quality of ischemia

  6. Dual-energy subtraction radiography of the breast

    International Nuclear Information System (INIS)

    Asaga, Taro; Masuzawa, Chihiro; Kawahara, Satoru; Motohashi, Hisahiko; Okamoto, Takashi; Tamura, Nobuo

    1988-01-01

    Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, beign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses. (author)

  7. Dual-energy subtraction radiography of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Asaga, Taro; Masuzawa, Chihiro; Kawahara, Satoru; Motohashi, Hisahiko; Okamoto, Takashi; Tamura, Nobuo

    1988-06-01

    Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, beign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses.

  8. Importance and Limitations of Scintigraphy of the Pancreas: Results of 200 Examinations involving Electronic Subtraction of the Image of the Liver; Interet et Limites de la Scintigraphie Pancreatique: Resultats de 200 Examens Pratiques avec Soustraction Electronique de l'Image du Foie

    Energy Technology Data Exchange (ETDEWEB)

    Blanquet, P.; Beck, C.; Pigneux, J.; Hecquet, M. F. [Hopital Saint-Andre, Unite de Recherches INSERM, Bordeaux (France)

    1969-05-15

    In the course of routine hospital practice, the authors carried out 200 scintigraphic scans of the pancreas with suppression of the image of the liver. The examinations were made with an Anger camera, used in conjunction with the integrating memory of a 4096-channel pulse analyser. With this arrangement it was possible to subtract the data provided by heavy colloids of {sup 198}Au taken up by the liver from data relating to {sup 75}Se-labelled selenomethionine incorporated by the liver or the pancreas. The technique used is simple and requires immobilization of the patient for about one hour. Its purpose is to give an image of the pancreas free from any superimposed image of the liver and also to provide information on the rate at which the labelled compound is stored in the gland. The dose absorbed by the pancreas is minimal, owing to the short length of time that the radioisotope remains within the gland. The dose received by the whole body is not negligible and therefore the number of examinations made on subjects with a clinically normal pancreas was limited to five. Although its principle is open to criticism, the subtraction technique gave completely satisfactory results in practice. Suppression of the liver image was not always complete but in all cases the image of the pancreas was sufficiently isolated to allow interpretation of it as a whole. It should, however, be noted that the zone of projection common to the two organs is often somewhat inhomogenous after subtraction has been effected. In subjects free from pancreatic disorders, the scintigram was in all cases normal. In the cases of confirmed chronic pancreatitis the picture is unequivocal. The tumours can manifest themselves in a variety of scintigraphic images, but the definition of the images may be regarded as satisfactory since in one case the scintigram showed up a tumorous formation estimated to measure 2 cm at that time. (author) [French] Les auteurs ont pratique, en routine hospitaliere, 200

  9. Deblurring in digital tomosynthesis by iterative self-layer subtraction

    Science.gov (United States)

    Youn, Hanbean; Kim, Jee Young; Jang, SunYoung; Cho, Min Kook; Cho, Seungryong; Kim, Ho Kyung

    2010-04-01

    Recent developments in large-area flat-panel detectors have made tomosynthesis technology revisited in multiplanar xray imaging. However, the typical shift-and-add (SAA) or backprojection reconstruction method is notably claimed by a lack of sharpness in the reconstructed images because of blur artifact which is the superposition of objects which are out of planes. In this study, we have devised an intuitive simple method to reduce the blur artifact based on an iterative approach. This method repeats a forward and backward projection procedure to determine the blur artifact affecting on the plane-of-interest (POI), and then subtracts it from the POI. The proposed method does not include any Fourierdomain operations hence excluding the Fourier-domain-originated artifacts. We describe the concept of the self-layer subtractive tomosynthesis and demonstrate its performance with numerical simulation and experiments. Comparative analysis with the conventional methods, such as the SAA and filtered backprojection methods, is addressed.

  10. BPHZL-subtraction scheme and axial gauges

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M.; Rebhan, A.; Schweda, M.; Piguet, O.

    1986-03-27

    The application of the BPHZL subtraction scheme to Yang-Mills theories in axial gauges is presented. In the auxillary mass formulation we show the validity of the convergence theorems for subtracted momentum space integrals, and we give the integral formulae necessary for one-loop calculations. (orig.).

  11. Development of digital subtraction system DAR-1200

    International Nuclear Information System (INIS)

    Kawai, Masumi; Shimizu, Yasumitsu; Ozaki, Takeshi; Sawada, Hiroshi; Uzuyama, Kazuhiro; Nishioka, Hiroyuki

    1989-01-01

    Digital subtraction angiography (DSA) has been of widespread use clinically, and it has attracted considerable attention in angiographic examination today. The merits of Shimadzu high resolution digital subtraction system DAR-1200 are reported in this paper. Furthermore, the principle and clinical usefullness of a new method of DSA called the Peak-Hold DSA are explained especially in details. (author)

  12. Digital subtraction angiography of the heart and lungs

    International Nuclear Information System (INIS)

    Moodie, D.S.; Yiannikas, J.

    1986-01-01

    This book contains 12 chapters. Some of the chapter titles are: Physical Principles of Cardiac Digital Subtraction Angiography, The Use of Intravenous Digital Subtraction Angiography in Evaluating Patients with Complex Congenital Heart Disease, Exercise Intravenous Digital Subtraction Angiograpny, Cardiomyopathic and Cardiac Neoplastic Disease, Digital Subtraction Angiography in the Catheterization Laboratory, and Cardiac Digital Subtraction Angiography - Future Directions

  13. Improved detection of pulmonary nodules on energy-subtracted chest radiographs with a commercial computer-aided diagnosis software: comparison with human observers

    International Nuclear Information System (INIS)

    Szucs-Farkas, Zsolt; Patak, Michael A.; Yuksel-Hatz, Seyran; Ruder, Thomas; Vock, Peter

    2010-01-01

    To retrospectively analyze the performance of a commercial computer-aided diagnosis (CAD) software in the detection of pulmonary nodules in original and energy-subtracted (ES) chest radiographs. Original and ES chest radiographs of 58 patients with 105 pulmonary nodules measuring 5-30 mm and images of 25 control subjects with no nodules were randomized. Five blinded readers evaluated firstly the original postero-anterior images alone and then together with the subtracted radiographs. In a second phase, original and ES images were analyzed by a commercial CAD program. CT was used as reference standard. CAD results were compared to the readers' findings. True-positive (TP) and false-positive (FP) findings with CAD on subtracted and non-subtracted images were compared. Depending on the reader's experience, CAD detected between 11 and 21 nodules missed by readers. Human observers found three to 16 lesions missed by the CAD software. CAD used with ES images produced significantly fewer FPs than with non-subtracted images: 1.75 and 2.14 FPs per image, respectively (p=0.029). The difference for the TP nodules was not significant (40 nodules on ES images and 34 lesions in non-subtracted radiographs, p = 0.142). CAD can improve lesion detection both on energy subtracted and non-subtracted chest images, especially for less experienced readers. The CAD program marked less FPs on energy-subtracted images than on original chest radiographs. (orig.)

  14. [Development of a digital chest phantom for studies on energy subtraction techniques].

    Science.gov (United States)

    Hayashi, Norio; Taniguchi, Anna; Noto, Kimiya; Shimosegawa, Masayuki; Ogura, Toshihiro; Doi, Kunio

    2014-03-01

    Digital chest phantoms continue to play a significant role in optimizing imaging parameters for chest X-ray examinations. The purpose of this study was to develop a digital chest phantom for studies on energy subtraction techniques under ideal conditions without image noise. Computed tomography (CT) images from the LIDC (Lung Image Database Consortium) were employed to develop a digital chest phantom. The method consisted of the following four steps: 1) segmentation of the lung and bone regions on CT images; 2) creation of simulated nodules; 3) transformation to attenuation coefficient maps from the segmented images; and 4) projection from attenuation coefficient maps. To evaluate the usefulness of digital chest phantoms, we determined the contrast of the simulated nodules in projection images of the digital chest phantom using high and low X-ray energies, soft tissue images obtained by energy subtraction, and "gold standard" images of the soft tissues. Using our method, the lung and bone regions were segmented on the original CT images. The contrast of simulated nodules in soft tissue images obtained by energy subtraction closely matched that obtained using the gold standard images. We thus conclude that it is possible to carry out simulation studies based on energy subtraction techniques using the created digital chest phantoms. Our method is potentially useful for performing simulation studies for optimizing the imaging parameters in chest X-ray examinations.

  15. Digital subtraction angiography for breast cancer

    International Nuclear Information System (INIS)

    Tsurumi, Kiyohiko; Okuyama, Nobuo

    1987-01-01

    We performed digital subtraction angiography (DSA) on 42 patients with breast diseases to investigate its efficiency. As a result we came to the following conclusions: 1. The sensitivity was well evaluated in intraarterial digital subtraction angiography (IA-DSA) of breast. 2. IA-DSA could diagnose difficult cases like cancer which had undergone augmentation mammoplasty, or like Paget's disease and others. 3. DSA was a safe examination method. 4. The sensitivity of IA-DSA of breast cancer is superior to intravenous digital subtraction angiography (IV-DSA). (author)

  16. Clinical usefulness of subtraction scintigraphy of the liver with Ga-67-citrate and Tc-99m-colloid

    International Nuclear Information System (INIS)

    Oyamada, H.; Terui, S.; Nagaiwa, K.; Kawai, H.; Fukukita, H.

    1983-01-01

    Subtraction scintigraphy of the liver with Ga-67-citrate and Tc-99m-colloid was performed for the radionuclide image diagnosis of intrahepatic masses, especially hepatoma. In this method the Tc-99m image was subtracted from the Ga-67 image. After normalizing both images, 4 different factors (0.6, 0.8, 1.0, and 1.2) were applied to the Tc-99m image before the subtraction. Finally, 4 subtraction images with different contrasts were obtained in one X-ray film. This method was found to be very useful in the assessment of intrahepatic focal accumulation of Ga-67, especially in cases with hepatoma, because it eliminated the uncertainty in the former method in which only visual judgment was done

  17. Temporal digital subtraction radiography with a personal computer digital workstation

    International Nuclear Information System (INIS)

    Kircos, L.; Holt, W.; Khademi, J.

    1990-01-01

    Technique have been developed and implemented on a personal computer (PC)-based digital workstation to accomplish temporal digital subtraction radiography (TDSR). TDSR is useful in recording radiologic change over time. Thus, this technique is useful not only for monitoring chronic disease processes but also for monitoring the temporal course of interventional therapies. A PC-based digital workstation was developed on a PC386 platform with add-in hardware and software. Image acquisition, storage, and processing was accomplished using 512 x 512 x 8- or 12-bit frame grabber. Software and hardware were developed to accomplish image orientation, registration, gray scale compensation, subtraction, and enhancement. Temporal radiographs of the jaws were made in a fixed and reproducible orientation between the x-ray source and image receptor enabling TDSR. Temporal changes secondary to chronic periodontal disease, osseointegration of endosseous implants, and wound healing were demonstrated. Use of TDSR for chest imaging was also demonstrated with identification of small, subtle focal masses that were not apparent with routine viewing. The large amount of radiologic information in images of the jaws and chest may obfuscate subtle changes that TDSR seems to identify. TDSR appears to be useful as a tool to record temporal and subtle changes in radiologic images

  18. Intra-arterial digital subtraction angiography of the carotid arteries

    International Nuclear Information System (INIS)

    Nakstad, P.; Bakke, S.J.; Kjartansson, O.; Nyhus, S.

    1986-01-01

    A cross-over test in intra-arterial digital subtraction angiography (IADSA) of the carotid arteries was performed in 50 patients to evaluate image quality and side-effects with iohexol and metrizoate injected at concentrations of 100 mg I/ml by hand. The image quality was excellent or good in all cases. Although the severity and the frequency of side-effects were higher with metrizoate, both contrast media were suitable for IADSA at this low concentration. No complications were seen. It was assumed that the risk with IADSA was less than that of conventional-selectivity and with small amounts of contrast media, as in this study. (orig.)

  19. [Design and development of the DSA digital subtraction workstation].

    Science.gov (United States)

    Peng, Wen-Xian; Peng, Tian-Zhou; Xia, Shun-Ren; Jin, Guang-Bo

    2008-05-01

    According to the patient examination criterion and the demands of all related departments, the DSA digital subtraction workstation has been successfully designed and is introduced in this paper by analyzing the characteristic of video source of DSA which was manufactured by GE Company and has no DICOM standard interface. The workstation includes images-capturing gateway and post-processing software. With the developed workstation, all images from this early DSA equipment are transformed into DICOM format and then are shared in different machines.

  20. Magnetization transfer contrast (MTC) and MTC-subtraction: enhancement of cartilage lesions and intracartilaginous degeneration in vitro

    International Nuclear Information System (INIS)

    Vahlensieck, M.; Dombrowski, F.; Leutner, C.; Wagner, U.; Reiser, M.

    1994-01-01

    Human articular cartilage from 16 cadaveric or amputated knees was studied using standard magnetic resonance imaging (MRI), on-resonance magnetization transfer contrast (MTC) and MTC-subtraction MRI. Results were compared with subsequent macroscopic and histopathological findings. MTC-subtraction and T2-weighted spin-echo images visualized cartilaginous surface defects with high sensitivity and specificity. MTC and T2-weighted spin-echo images revealed intra-cartilaginous signal loss without surface defects in 80% of the cases, corresponding to an increased collagen concentration. It is concluded that MTC is sensitive to early cartilage degeneration and MTC-subtraction can be helpful in detecting cartilage defects. (orig.)

  1. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the subtraction terms I

    Science.gov (United States)

    Somogyi, Gábor; Trócsányi, Zoltán

    2008-08-01

    In previous articles we outlined a subtraction scheme for regularizing doubly-real emission and real-virtual emission in next-to-next-to-leading order (NNLO) calculations of jet cross sections in electron-positron annihilation. In order to find the NNLO correction these subtraction terms have to be integrated over the factorized unresolved phase space and combined with the two-loop corrections. In this paper we perform the integration of all one-parton unresolved subtraction terms.

  2. Digital subtraction angiography with an Isocon camera system: clinical applications

    International Nuclear Information System (INIS)

    Barbaric, Z.L.; Gomes, A.S.; Deckard, M.E.; Nelson, R.S.; Moler, C.L.

    1984-01-01

    A new imaging system for digital subtraction angiography (DSA) was evaluated in 30 clinical studies. The image receptor is a 25 X 25 cm, 12 par gadolinium oxysulfate rare-earth screen whose light output is focused to a low-light-level Isocon camera. The video signal is digitized and processed by an image-array processor containing 31 512 X 512 memories 8 bits deep. In most patients, intraarterial DSA studies were done in conjunction with conventional arteriography. In these arterial studies, images adequate to make a specific diagnosis were obtained using half the radiation dose and half the amount of contrast material needed for conventional angiography. In eight intravenous studies performed either to identify renal artery stenosis or for evaluation of congenital heart anomalies, the images were diagnostic but objectionably noisy

  3. Method and apparatus for performing digital intravenous subtraction angiography

    International Nuclear Information System (INIS)

    Stein, J.A.

    1986-01-01

    This invention relates to digital intravenous subtraction angiography (DISA), and more particularly concerns novel apparatus and techniques for providing high resolution angiograms with equipment that coacts with existing standard medical X-ray equipment. A typical medical X-ray generator provides low mA, continuous X-ray exposures illuminating a standard image intensifier producing an image scanned by a conventional television camera to produce a video signal. An analog-to-digital converter digitizes the signal, and adding means adds the digital frame signals together in real time to provide an intermediate digital signal representing the addition of 5 to 20 frames. Digital storage means store the intermediate image signals. Preferably there are two system memories with means for summing a subsequent intermediate image in the second memory while a previously-formed intermediate image is being transferred to disk storage

  4. Methods in Astronomical Image Processing

    Science.gov (United States)

    Jörsäter, S.

    A Brief Introductory Note History of Astronomical Imaging Astronomical Image Data Images in Various Formats Digitized Image Data Digital Image Data Philosophy of Astronomical Image Processing Properties of Digital Astronomical Images Human Image Processing Astronomical vs. Computer Science Image Processing Basic Tools of Astronomical Image Processing Display Applications Calibration of Intensity Scales Calibration of Length Scales Image Re-shaping Feature Enhancement Noise Suppression Noise and Error Analysis Image Processing Packages: Design of AIPS and MIDAS AIPS MIDAS Reduction of CCD Data Bias Subtraction Clipping Preflash Subtraction Dark Subtraction Flat Fielding Sky Subtraction Extinction Correction Deconvolution Methods Rebinning/Combining Summary and Prospects for the Future

  5. On the usefulness of portal monitor unit subtraction in radiation therapy

    International Nuclear Information System (INIS)

    Kuperman, Vadim Y; Lubich, Leslie M

    2003-01-01

    In order to avoid additional dose to patients caused by portal imaging with megavoltage x-rays, portal monitor units (MUs) are frequently subtracted from the actual treatment MUs. This study examines the usefulness of portal MU subtraction in radiation therapy. For 11 prostate cancer patients treated with 23 MV photons, dose to prostate due to portal filming with 6 MV photons was determined. In all 11 patients subtraction of portal MU values from the actual treatment MUs resulted in a small underdosing of the prostate with an average treatment error of -0.5%. Portal filming without MU subtraction would cause small overdosing of the prostate with an average treatment error of 1.2%. The results of this study indicate that the benefits of portal MU subtraction are in doubt if (a) the energy of treatment x-rays is much higher than that of the portal x-rays and/or (b) when radiotherapy is performed with physical wedges. Based on the obtained results, we argue against unconditional use of the portal MU subtraction method to eliminate the dose from portal imaging

  6. Thallium-201 and technetium-99m pertechnetate subtraction scintigraphy in patients with hyperparathyroidism

    International Nuclear Information System (INIS)

    Kuwashima, Shigeko; Koizumi, Mitsuru; Goto, Masafumi; Nomura, Toshiharu; Fujioka, Mutsuhisa; Watari, Tsutomu

    1992-01-01

    A reliable technique for detecting and localizing abnormal parathyroid tissue has been a persistent problem. We evaluated thallium-technetium (Tl/Tc) subtraction scintigraphy in 16 patients with clinical biochemical evidence of hyperparathyroidism prior to other diagnostic methods and surgery. Seven patients had surgery and were confirmed to have parathyroid adenoma or hyperplasia. The other methods included ultrasonography (US) in 6 patients, computed tomography (CT) in 10 patients, magnetic resonance imaging (MRI) in 8 patients, and bone scintigraphy in 7 patients. In patients who had several imaging modalities, the detection rate was significantly better for Tl/Tc subtraction scan than for US, CT or MRI. Bote scintigraphy, though not so sensitive as Tl/Tc subtraction studies, was an important tool for evaluating metabolic bone disorder including hyperparathyroidism and renal osteodystrophy. Thus, Tl/Tc subtraction scan is more useful for diagnosis when hyperparathyroidism is suspected if both Tl/Tc subtraction scan and bone scan are performed. The detectability depended on the mass size, and detection of abnormal glands was greater for adenoma than for hyperplasia. The results suggest that Tl/Tc subtraction scan is a simple, non-invasive and useful tool for locating parathyroid abnormality even when compared with MRI. (author)

  7. Detection of intracranial aneurysms using three-dimensional multidetector-row CT angiography: Is bone subtraction necessary?

    International Nuclear Information System (INIS)

    Hwang, Seung Bae; Kwak, Hyo Sung; Han, Young Min; Chung, Gyung Ho

    2011-01-01

    Purpose: The aim of this study was to evaluate the usefulness of three-dimensional CT angiography (3D CTA) with bone subtraction in a comparison with 3D CTA without bone subtraction for the detection of intracranial aneurysms. Materials and methods: Among 337 consecutive patients who had intracranial aneurysms detected on 3D CTA, 170 patients who underwent digital subtraction angiography (DSA) were included in the study. CTA was performed with a 16-slice multidetector-row CT (MDCT) scanner. We created the 3D reconstruction images with and without bone subtraction by using the volume rendering technique. Three neuroradiologists in a blinded fashion interpreted both 3D CTA images with and without bone subtraction. The diagnostic accuracy of both techniques was evaluated using the alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive value were also evaluated. Results: A total of 200 aneurysms (size: 2-23 mm) were detected in 170 patients. The area under the receiver operating characteristic curve (Az) for 3D CTA with bone subtraction (mean, Az = 0.933) was significantly higher than that for 3D CTA without bone subtraction (mean, Az = 0.879) for all observers (P < 0.05). The sensitivity of 3D CTA with bone subtraction for three observers was 90.0, 92.0 and 92.5%, respectively, while the sensitivity of 3D CTA without bone subtraction was 83.5, 83.5 and 87.5%, respectively. No significant difference in positive predictive value was observed between the two modalities. Conclusions: 3D CTA with bone subtraction showed significantly higher diagnostic accuracy for the detection of intracranial aneurysms as compared to 3D CTA without bone subtraction.

  8. Counting the mismatches - lung ventilation/perfusion subtraction index

    International Nuclear Information System (INIS)

    Anderson, T.C.; Evans, S.G.; Larcos, G.; Farlow, D.C.

    1998-01-01

    Full text: There is potential for interobserver variability in interpretation of ventilation/perfusion (V/Q) scans. Objective quantification of V/Q mismatch could be useful. Thus, the aim of this study is to determine the validity of image subtraction in a group of 27 patients (11 men, 8 women; mean age 59.4 years [range 21-81 years])investigated by V/Q scans for suspected pulmonary emboli. A standard 6 view V/Q scan was obtained with two cobalt markers used on the anterior and posterior surfaces for image alignment. Ventilation images were normalised to the perfusion using an area of normal ventilation and perfusion. With the use of automated, and if required, manual alignment, perfusion images were subtracted from ventilation, with a median filter applied. A summed index of mismatch for each lung scan was calculated from the difference. This index was then retrospectively compared to the result reported by one of four experienced physicians. Two patients with chronic obstructive airways disease were excluded from analysis. We conclude that high probability V/Q scans can be differentiated from low probability studies using this index; further prospective investigation in a larger cohort is warranted

  9. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA.

    Science.gov (United States)

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Schwenke, Carsten; Hamm, Bernd; Wagner, Moritz

    2016-12-01

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). • 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust NE-MRA technique at 3T • 2D-bSSFP-MRA outperforms 3D flow-dependent subtractive MRA (3D-FSE-MRA) as NE-MRA of calf arteries • 2D-bSSFP-MRA is a promising alternative to CE-MRA for calf PAOD evaluation.

  10. Evaluation of left ventricular function using digital subtraction ventriculography

    International Nuclear Information System (INIS)

    Yiannikas, J.; Detrano, R.

    1986-01-01

    Digital subtraction ventriculography following injections of contrast via peripheral veins provides excellent images to assess left ventricular function. The images are essentially identical to those following DCV, but allow more uniform mixing of contrast in the left ventricular chamber. Furthermore, few, if any, cardiac arrhythmias occur, hence obviating difficulties that arise from DCV. The spatial resolution of the method is such that regional wall motion assessment of ventricular function is more accurate than that of other noninvasive imaging methods. The use of video-densitometry allows accurate assessment of left ventricular function even when the left ventricular cavity is nonsymmetrically deformed and aneurysmal. In the setting of the cardiac catheterization laboratory, digital ventriculography may provide a safer means of assessing left ventricular function when critical coronary or myocardial disease is present and allows multiple assessments of ventricular function during the same study. Although excellent correlations with standard ventriculography have been noted by all workers, significant discrepancies still exist in individual patients, particularly in the calculations of end diastolic volumes. In the authors experience and in those of most workers, the largest discrepancies existed in patients in whom suboptimal studies are included for analysis. The most frequent reason for the occasional suboptimal study as with all digital subtraction work is the misregistration that results from motion

  11. Intraarterial digital subtraction angiography applied to diagnosis of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Nishizawa, Sadahiko; Sano, Akira; Imanaka, Kazufumi; Sasai, Keisuke; Nagae, Toshiyuki; Mizutani, Masaru; Hatabu, Hiroto; Sadatou, Norihiro; Kuroda, Yasumasa

    1985-12-01

    This paper deals with diagnostic values of intraarterial digital subtraction angiography (IADSA) for evaluating hepatocellular carcinoma. The present series consists of 44 patients with hepatocellular carcinoma, who underwent IADSA combined with conventional hepatic angiography 67 times in total. The evaluated vessels by IADSA included 70 hepatic arteries and 36 portal veins. Comparative studies on the image quality of IADSA with conventional angiography were made in referring to the tumor stain for arteriograms and resolution of intrahepatic portal branches for portograms. Diagnostic superiority including equality of DSA image to conventional was noted in arteriograms: 72.7 % in the right lobe and 86 % in the left. Most deteriorated DSA images were caused by misregistration artifacts. IADSA portography revealed basically diagnostic values to demonstrate lobar, segmental or more peripheral branches in about 95 % of cases studied. DSA, characterized by high contrast resolution and real-time subtraction, offered important and effective informations for interventional angiography as well as resectability of the tumors, requiring less contrast medium.

  12. Using a digital signal processor as a data stream controller for digital subtraction angiography

    International Nuclear Information System (INIS)

    Meng, J.D.; Katz, J.E.

    1991-10-01

    High speed, flexibility, and good arithmetic abilities make digital signal processors (DSP) a good choice as input/output controllers for real time applications. The DSP can be made to pre-process data in real time to reduce data volume, to open early windows on what is being acquired and to implement local servo loops. We present an example of a DSP as an input/output controller for a digital subtraction angiographic imaging system. The DSP pre-processes the raw data, reducing data volume by a factor of two, and is potentially capable of producing real-time subtracted images for immediate display

  13. Evaluation and quality control of digital subtraction angiography systems

    International Nuclear Information System (INIS)

    Louisot, P.

    1986-04-01

    After reviewing the development of systems used in angiography, we rewind the medical interest and describe the steps of an angiographic examination. The following chapter is dedicated to the techniques used for the digitalization of video images. The components of the system involved in the image acquisition are thoroughly investigated in chapter 4. Then, we analyse the capabilities of the machines available in France in 1985. Chapter 6 is devoted to the criteria of quality in digital imaging. In order to assign qualitative values to the above criteria, we design a control procedure which is described in chapter 7. The procedure thus allows the estimate of the physical performances of angiographic digital subtraction systems [fr

  14. A simple digital subtraction angiographic instrument

    International Nuclear Information System (INIS)

    Ando, Hiroshi; Kobayashi, Tsuyoshi; Imai, Yutaka; Yanagishita, Akira

    1983-01-01

    A digital subtraction angiographic instrument was manufactured using a conventional x-ray TV for gastrointestinal series and a computer for processing of nuclear medical data. The results of visualization of the aorta and its primary branches were reviewed with demonstrable cases. (Chiba, N.)

  15. Digital subtraction angiography: myths and reality

    International Nuclear Information System (INIS)

    Levin, D.C.

    1984-01-01

    Some of the claims made about digital subtraction angiography (DSA) when it was first developed have turned out to be greatly exaggerated, and some members of the radiologic community have become disillusioned with its capabilities. The author discusses some of the limitations of DSA, and concludes that the advantages of DSA outweigh its limitations

  16. Digital subtraction angiography of carotid bifurcation

    International Nuclear Information System (INIS)

    Vries, A.R. de.

    1984-01-01

    This study demonstrates the reliability of digital subtraction angiography (DSA) by means of intra- and interobserver investigations as well as indicating the possibility of substituting catheterangiography by DSA in the diagnosis of carotid bifurcation. Whenever insufficient information is obtained from the combination of non-invasive investigation and DSA, a catheterangiogram will be necessary. (Auth.)

  17. Probabilistic Model-based Background Subtraction

    DEFF Research Database (Denmark)

    Krüger, Volker; Anderson, Jakob; Prehn, Thomas

    2005-01-01

    is the correlation between pixels. In this paper we introduce a model-based background subtraction approach which facilitates prior knowledge of pixel correlations for clearer and better results. Model knowledge is being learned from good training video data, the data is stored for fast access in a hierarchical...

  18. Digital subtraction angiography: first 900 cases

    International Nuclear Information System (INIS)

    Rodgers, H.

    1984-01-01

    The diagnostic technique of digital subtraction angiography (DSA) is briefly outlined. The operational and technical experiences with a DR-960 DSA system used in the examination of the first 900 cases at St. Thomas' Hospital, London are described. (U.K.)

  19. Radionuclide identification using subtractive clustering method

    International Nuclear Information System (INIS)

    Farias, Marcos Santana; Mourelle, Luiza de Macedo

    2011-01-01

    Radionuclide identification is crucial to planning protective measures in emergency situations. This paper presents the application of a method for a classification system of radioactive elements with a fast and efficient response. To achieve this goal is proposed the application of subtractive clustering algorithm. The proposed application can be implemented in reconfigurable hardware, a flexible medium to implement digital hardware circuits. (author)

  20. Dynamic contrast-enhanced subtraction MR angiography in intracranial vascular abnormalities

    International Nuclear Information System (INIS)

    Takano, K.; Ono, H.; Utsunomiya, H.; Okazaki, M.; Tanaka, A.

    1999-01-01

    We present our clinical experience with dynamic contrast-enhanced MR angiography (MRA) with subtraction for assessing intracranial vascular abnormalities. Ten patients with various cerebrovascular disorders underwent dynamic contrast-enhanced MRA on a 1.0-T system. Thirty sections (2 mm) were acquired in 29-30 s. Maximum intensity projection images and subtracted source images were compared with those obtained by conventional angiography. In all cases, the presence or absence of abnormalities in the targeted vessels, as well as the morphology of the sagittal sinuses, was clearly visualized as in conventional angiography, without any obstructions such as hyperintense hematomas or thrombi, or intraluminal turbulence. Although the temporal and spatial resolutions with current hardware are insufficient, these preliminary results suggest that dynamic contrast-enhanced MRA with subtraction may be useful for assessing vascular lesions with hemorrhage or thrombus, and the dural sinuses. (orig.)

  1. Digital subtraction angiography in 105 living renal transplant donors

    International Nuclear Information System (INIS)

    Suh, Ho Jong; Oh, Kyung Seung; Kim, So Sun; Huh, Jin Do; Kim, Ho Joon; Chun, Byung Hee; Joh, Young Duck

    1989-01-01

    In order to analyze the number and length of the renal arteries and to evaluate abnormalities of the renal parenchyma and vessel, digital subtraction angiogram images of 105 potential renal donors (45 men and 60 women aged 17-66 years) were studied retrospectively. For the entire series, 31 donors had multiple renal arteries on one side (15 on the left, 11 on the right) and 5 donors on the both sides. 89 donors were family related either parents or siblings of recipients. The estimation of the length of the renal artery was based on the mean height of the second lumbar vertebral body (L2). The right renal artery is significant longer than on the left and measured more than the height of L2 vertebral body in 84 cases on the right and 60 cases on the left. Twenty two donors underwent right nephrectomy due to presence of multiple renal arteries on the left (N=14), proximal bifurcation of left main renal artery (N=3), and young females in reproductive age (N=5). Unexpected abnormalities found with angiogram were seen in 7 cases and they include renal artery stenosis (N=2), renal cysts (N=4) and focal infarction (N=1). In cases of the renal cysts and focal infarction, there were no serious complications related to the abnormalities. It is conclude that intra-arterial digital subtraction angiography is safe and efficient method to image renal anatomy of the potential renal donors

  2. Motion compensation in digital subtraction angiography using graphics hardware.

    Science.gov (United States)

    Deuerling-Zheng, Yu; Lell, Michael; Galant, Adam; Hornegger, Joachim

    2006-07-01

    An inherent disadvantage of digital subtraction angiography (DSA) is its sensitivity to patient motion which causes artifacts in the subtraction images. These artifacts could often reduce the diagnostic value of this technique. Automated, fast and accurate motion compensation is therefore required. To cope with this requirement, we first examine a method explicitly designed to detect local motions in DSA. Then, we implement a motion compensation algorithm by means of block matching on modern graphics hardware. Both methods search for maximal local similarity by evaluating a histogram-based measure. In this context, we are the first who have mapped an optimizing search strategy on graphics hardware while paralleling block matching. Moreover, we provide an innovative method for creating histograms on graphics hardware with vertex texturing and frame buffer blending. It turns out that both methods can effectively correct the artifacts in most case, as the hardware implementation of block matching performs much faster: the displacements of two 1024 x 1024 images can be calculated at 3 frames/s with integer precision or 2 frames/s with sub-pixel precision. Preliminary clinical evaluation indicates that the computation with integer precision could already be sufficient.

  3. Intravenous digital subtraction angiography contrast media time-concentration curves

    International Nuclear Information System (INIS)

    Burbank, F.H.; Brody, W.R.

    1985-01-01

    At any specified radiation dose and system signal-to-noise ratio, temporal (masked-mode) intravenous digital subtraction angiography (IV-DSA) image quality is dependent upon the shape of the arterial time-concentration curve produced by the intravenous injection of iodinated contrast media. If contrast media appears in the arterial circulation as a compact bolus and reaches a high peak, images containing low or no iodine (the mask image or images) and high iodine concentration (the enhanced image or images) can be obtained close together in time, maximizing contrast media enhancement and minimizing the potential for spatial movement (misregistration). However, if the contrast media bolus is broad, rising slowly to a low concentration peak, sufficient time may pass for movement to occur and the opacification difference between the mask image and the enhanced image may be too small to visualize vessels of interest. Consequently, knowledge of the rules which govern the formation of time-concentration curves is central to IV-DSA

  4. Visualization of the renal venous system by renal arteriography with digital subtraction angiography

    International Nuclear Information System (INIS)

    Nagai, Jun

    1989-01-01

    The purpose of this study was to obtain vivid and precise images of intrarenal venous branching using DSA for renal arteriography. The type of system used was an ADAC DPS-4100C with 70-80 kVp, and 320 mA, 25-50 msec at 6 frames/sec. The duration was 10 sec and the matrix size was 512x512. In order to retain clear subtracted images of intrarenal venous branching with minimal noise the three frames were selected on the time-density curve of DSA: (Fig.3). 1) a frame on which renal arteries disappear (frame X), 2) the frame with highest renal venous density value as (frame Y), 3) the difference of the nephrogram density between X and Y frames in which only the density of the nephrogram decreases (frame Z). The mask image is the image subtracted by the equation of the weighted averaging method on X and Z frame and is subtracted from the image of Y frame in the final step. By this method, 40 kidneys in 36 patients were studied, and the intrarenal venous branches up to the interlobar vein was clearly demonstrated in 28 of these cases (70%). This method is useful to estimate the extent of intrarenal lesions and detect abnormal renal blood flow compared with conventional temporal subtraction method. (author)

  5. Signal-to-noise ratio measurement in parallel MRI with subtraction mapping and consecutive methods

    International Nuclear Information System (INIS)

    Imai, Hiroshi; Miyati, Tosiaki; Ogura, Akio; Doi, Tsukasa; Tsuchihashi, Toshio; Machida, Yoshio; Kobayashi, Masato; Shimizu, Kouzou; Kitou, Yoshihiro

    2008-01-01

    When measuring the signal-to-noise ratio (SNR) of an image the used parallel magnetic resonance imaging, it was confirmed that there was a problem in the application of past SNR measurement. With the method of measuring the noise from the background signal, SNR with parallel imaging was higher than that without parallel imaging. In the subtraction method (NEMA standard), which sets a wide region of interest, the white noise was not evaluated correctly although SNR was close to the theoretical value. We proposed two techniques because SNR in parallel imaging was not uniform according to inhomogeneity of the coil sensitivity distribution and geometry factor. Using the first method (subtraction mapping), two images were scanned with identical parameters. The SNR in each pixel divided the running mean (7 by 7 pixels in neighborhood) by standard deviation/√2 in the same region of interest. Using the second (consecutive) method, more than fifty consecutive scans of the uniform phantom were obtained with identical scan parameters. Then the SNR was calculated from the ratio of mean signal intensity to the standard deviation in each pixel on a series of images. Moreover, geometry factors were calculated from SNRs with and without parallel imaging. The SNR and geometry factor using parallel imaging in the subtraction mapping method agreed with those of the consecutive method. Both methods make it possible to obtain a more detailed determination of SNR in parallel imaging and to calculate the geometry factor. (author)

  6. Accuracy of digital subtraction radiography in combination with a contrast media in assessment of proximal caries depth

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2008-07-01

    Full Text Available Background and aims. Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these lesions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiography in combination with barium sulfate in diagnosing proximal dental caries with histopathologic evaluation. Materials and methods. In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments. Results. The mean depths (± SD of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P < 0.05. However, the differences were not statistically significant between subtracted images and histopathologic sections. The average intra-class correlation coefficient was 0.7241 (CI: 95%. Conclusion. The present study has demonstrated that digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation.

  7. The role of contrast-enhanced digital subtraction MRI in the diagnosis of vertebral metastasic tumors

    International Nuclear Information System (INIS)

    Xiao Yeyu; Yang Jun; Qi Weili; Liu Qize; Hong Bikai; Wu Renhua

    2008-01-01

    Objective: To evaluate the contrast-enhanced digital subtraction MRI in the diagnosis of vertebral metastasic tumors. Methods 66 vertebral metastasic tumors in 43 patients were examined with conventional MRI (T 1 WI, STIR and Contrast-enhanced T 1 WI) and contrast-enhanced digital subtraction MR imaging. All lesions were histologically proved. The quantity and characteristic imaging signs (including spiculation, bull eye sign and irregular edge) of lesions were detected separately by different sequences. K independent samples test was used. Results: The detection rates of 35 vertebral metastasic tumors with vertebral morphological changes were same in all MR sequences. But in the other 31 lesions without vertebral morphological changes, the detection rates were different and STIR was the highest in all sequences. Contrast-enhanced digital subtraction MRI was more sensitive than all the conventional MR sequences in finding characteristic imaging signs with statistically significant differences. Conclusion: Contrast enhanced subtraction MRI is an useful and convenient technique which has great value in finding vertebral metastasic tumors and depicting the characteristic imaging signs. (authors)

  8. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk [Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    2009-03-15

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 {mu}m and the range of lesional area was 36.95-138.52 mm{sup 2}. The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  9. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    International Nuclear Information System (INIS)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk; Choi, Yong Suk; Hwang, Eui Hwan

    2009-01-01

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 μm and the range of lesional area was 36.95-138.52 mm 2 . The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  10. Wilson expansion in the minimal subtraction scheme

    International Nuclear Information System (INIS)

    Smirnov, V.A.

    1989-01-01

    The small distance expansion of the product of composite fields is constructed for an arbitrary renormalization procedure of the type of minimal subtraction scheme. Coefficient functions of the expansion are expressed explicitly through the Green functions of composite fields. The expansion has the explicity finite form: the ultraviolet (UV) divergences of the coefficient functions and composite fields are removed by the initial renormalization procedure while the infrared (IR) divergences in massless diagrams with nonvanishing contribution into the coefficient functions are removed by the R-operation which is the IR part of the R-operation. The latter is the generalization of the dimensional renormalization in the case when both UV and IR divergences are present. To derive the expansion, a ''pre-subtracting operator'' is introduced and formulas of the counter-term technique are exploited

  11. Subtracting and Fitting Histograms using Profile Likelihood

    CERN Document Server

    D'Almeida, F M L

    2008-01-01

    It is known that many interesting signals expected at LHC are of unknown shape and strongly contaminated by background events. These signals will be dif cult to detect during the rst years of LHC operation due to the initial low luminosity. In this work, one presents a method of subtracting histograms based on the pro le likelihood function when the background is previously estimated by Monte Carlo events and one has low statistics. Estimators for the signal in each bin of the histogram difference are calculated so as limits for the signals with 68.3% of Con dence Level in a low statistics case when one has a exponential background and a Gaussian signal. The method can also be used to t histograms when the signal shape is known. Our results show a good performance and avoid the problem of negative values when subtracting histograms.

  12. Subleading power corrections for N -jettiness subtractions

    Science.gov (United States)

    Moult, Ian; Rothen, Lorena; Stewart, Iain W.; Tackmann, Frank J.; Zhu, Hua Xing

    2017-04-01

    The N -jettiness observable TN provides a way of describing the leading singular behavior of the N -jet cross section in the τ =TN/Q →0 limit, where Q is a hard interaction scale. We consider subleading-power corrections in the τ ≪1 expansion, and employ soft-collinear effective theory to obtain analytic results for the dominant αsτ ln τ and αs2τ ln3τ subleading terms for thrust in e+e- collisions and 0-jettiness for q q ¯-initiated Drell-Yan-like processes at hadron colliders. These results can be used to significantly improve the numerical accuracy and stability of the N -jettiness subtraction technique for performing fixed-order calculations at next-to-leading order and next-to-next-to-leading order. They reduce the size of missing power corrections in the subtractions by an order of magnitude. We also point out that the precise definition of N -jettiness has an important impact on the size of the power corrections and thus the numerical accuracy of the subtractions. The sometimes employed definition of N -jettiness in the hadronic center-of-mass frame suffers from power corrections that grow exponentially with rapidity, causing the power expansion to deteriorate away from central rapidity. This degradation does not occur for the original N -jettiness definition, which explicitly accounts for the boost of the Born process relative to the frame of the hadronic collision, and has a well-behaved power expansion throughout the entire phase space. Integrated over rapidity, using this N -jettiness definition in the subtractions yields another order of magnitude improvement compared to employing the hadronic-frame definition.

  13. Background dose subtraction in personnel dosimetry

    International Nuclear Information System (INIS)

    Picazo, T.; Llorca, N.; Alabau, J.

    1997-01-01

    In this paper it is proposed to consider the mode of the frequency distribution of the low dose dosemeters from each clinic that uses X rays as the background environmental dose that should be subtracted from the personnel dosimetry to evaluate the doses due to practice. The problems and advantages of this indirect method to estimate the environmental background dose are discussed. The results for 60 towns are presented. (author)

  14. Moving object detection using background subtraction

    CERN Document Server

    Shaikh, Soharab Hossain; Chaki, Nabendu

    2014-01-01

    This Springer Brief presents a comprehensive survey of the existing methodologies of background subtraction methods. It presents a framework for quantitative performance evaluation of different approaches and summarizes the public databases available for research purposes. This well-known methodology has applications in moving object detection from video captured with a stationery camera, separating foreground and background objects and object classification and recognition. The authors identify common challenges faced by researchers including gradual or sudden illumination change, dynamic bac

  15. Sky Subtraction with Fiber-Fed Spectrograph

    Science.gov (United States)

    Rodrigues, Myriam

    2017-09-01

    "Historically, fiber-fed spectrographs had been deemed inadequate for the observation of faint targets, mainly because of the difficulty to achieve high accuracy on the sky subtraction. The impossibility to sample the sky in the immediate vicinity of the target in fiber instruments has led to a commonly held view that a multi-object fibre spectrograph cannot achieve an accurate sky subtraction under 1% contrary to their slit counterpart. The next generation of multi-objects spectrograph at the VLT (MOONS) and the planed MOS for the E-ELT (MOSAIC) are fiber-fed instruments, and are aimed to observed targets fainter than the sky continuum level. In this talk, I will present the state-of-art on sky subtraction strategies and data reduction algorithm specifically developed for fiber-fed spectrographs. I will also present the main results of an observational campaign to better characterise the sky spatial and temporal variations ( in particular the continuum and faint sky lines)."

  16. Subtractive fabrication of ferroelectric thin films with precisely controlled thickness

    Science.gov (United States)

    Ievlev, Anton V.; Chyasnavichyus, Marius; Leonard, Donovan N.; Agar, Joshua C.; Velarde, Gabriel A.; Martin, Lane W.; Kalinin, Sergei V.; Maksymovych, Petro; Ovchinnikova, Olga S.

    2018-04-01

    The ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. However, common thin-film growth techniques introduce a number of limitations related to the concentration of defects on film interfaces and surfaces that limit the scope of systems that can be produced and studied experimentally. Here, we developed an ion-beam based subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. To accomplish this we transformed a multimodal imaging platform that combines time-of-flight secondary ion mass spectrometry with atomic force microscopy to a unique fabrication tool that allows for precise sputtering of the nanometer-thin layers of material. To demonstrate fabrication of thin-films with in situ feedback and control on film thickness and functionality we systematically studied thickness dependence of ferroelectric switching of lead-zirconate-titanate, within a single epitaxial film. Our results demonstrate that through a subtractive film fabrication process we can control the piezoelectric response as a function of film thickness as well as improve on the overall piezoelectric response versus an untreated film.

  17. Removal of arterial wall calcifications in CT angiography by local subtraction

    International Nuclear Information System (INIS)

    Straten, Marcel van; Venema, Henk W.; Streekstra, Geert J.; Reekers, Jim A.; Heeten, Gerard J. den; Grimbergen, Cornelis A.

    2003-01-01

    CT Angiography (CTA) is an established technique for the minimally invasive imaging of arteries. The technique of maximum intensity projection (MIP) is often used to get a comprehensive overview of the vascular anatomy. On a MIP, however, arterial wall calcifications may hinder the visualization of the arterial lumen. These calcifications are in direct contact with the contrast-enhanced blood, which makes removal difficult. We present a local subtraction method for the automatic removal of these calcifications. In our approach a second CT scan has to be made, prior to contrast injection. The calcifications in both scans are registered prior to subtraction to compensate for displacements in between the two scans. Local subtraction results are compared with results obtained by thresholding. The method was tested in a phantom and with data from four patients. The phantom represented an artery with different types of stenosis. Data were used from patients for which CTA of the renal arteries was performed. For two patients the electrocardiogram (ECG) was recorded during the CTA examination, making retrospective cardiac gated reconstructions possible. Both the phantom and the patient study showed that the local subtraction method is capable of removing calcifications and visualizing the residual lumen. In the patient study it appeared that some artifacts remained for higher pitch values. We conclude that the local subtraction method is less subjective and more accurate than thresholding. Best results are obtained by use of a small pitch, at the expense of the volume covered during a single breath hold

  18. Effect of relative nanohole position on colour purity of ultrathin plasmonic subtractive colour filters

    International Nuclear Information System (INIS)

    Sun, L B; Hu, X L; Zhang, D X; Zeng, Beibei; Wang, L S; Yang, S M; Tai, R Z; Fecht, H J; Jiang, J Z

    2015-01-01

    Plasmonic subtractive color filters through patterning periodic nanostructures on ultrathin Ag films deposited on a glass substrate, exhibiting good durability, simple fabrication, and flexible color tunability, have attracted considerable attention due to their tremendous potential applications. While previous studies have mainly focused on their extraordinary physical mechanisms, color purity, which is another key parameter for high quality imaging applications, has been much less investigated. In this work, we demonstrate that the relative position of nanoholes patterned on ultrathin Ag films can largely affect the color purity of plasmonic subtractive color filters. The calculated results agree reasonably well with the experimental data, revealing that the purity of subtractive colors can be improved by changing the nanohole arrays from square lattice to triangular lattice without reducing transmission at visible frequencies. In addition, underlying mechanisms are clarified by systematically analyzing the dominant valley in transmission spectra. (paper)

  19. A study on computer-aided diagnosis based on temporal subtraction of sequential chest radiographs (in Japanese)

    International Nuclear Information System (INIS)

    Kano, Akiko

    2001-01-01

    An automated digital image subtraction technique for use with pairs of temporally sequential chest radiographs has been developed to aid radiologists in the detection of interval changes. Automated image registration based on nonlinear geometric warping is performed prior to subtraction in order to deal with complicated radiographic misregistration. Processing includes global matching, to achieve rough registration between the entire lung fields in the two images, and local matching, based on a cross-correlation method, to determine local shift values for a number of small regions. A proper warping of x,y-coordinates is determined by fitting two-dimensional polynomials to the distributions of the shift values. One image is warped and then subtracted from the other. The resultant subtraction images were able to enhance the conspicuity of various types of interval changes. Improved global matching based on a weighted template matching method achieved robust registration even with photofluorographs taken in chest mass screening programs, which had previously presented us with a relatively large number of poor-registration images. The new method was applied to 129 pairs of chest mass screening images, and offered registration accuracy as good as manual global matching. An observer test using 114 cases including 57 lung cancer cases presented better sensitivity and specificity on average compared to conventional comparison readings. In addition, newly developed image processing that eliminates the rib edge artifacts in subtraction images was applied to 26 images having pathological interval changes; results showed the potential for application to automated schemes for the detection of interval change patterns. With its capacity to improve the diagnostic accuracy of chest radiographs, the chest temporal subtraction technique promises to become an important element of computer-aided diagnosis (CAD) systems

  20. Evaluation of left ventricular function by digital subtraction angiography

    International Nuclear Information System (INIS)

    Kuribayashi, Sachio; Ootaki, Makoto; Matsuyama, Seiya; Kanemoto, Nariaki; Furuya, Hideo

    1985-01-01

    Effects of contrast medium doses on left ventriculographic images using intravenous digital subtraction angiography (IVDSA-LVG) were assessed. The validity of IVDSA-LVG in evaluating ejection fraction (FF) and left ventricular regional wall motion was determined by comparison with conventional left ventriculography using direct injection (direct LVG). The advantages of left ventriculography using intraarterial subtraction angiography (IADSA-LVG) performed by injecting small doses of contrast media directly into the left ventricle were stressed. 1. To assess the effects of doses of contrast media on IVDSA-LVG, 10, 20, and 30 ml Urografin-76 were injected into the superior vena cava in 16 patients, and the resulting images were compared in each patient. With only 10 ml contrast medium, left ventricular opacification was fairly good, and regional wall motion was evaluated in many cases, but 30 ml were needed to calculate ventricular volume and EF. 2. To determine the validity of IVDSA-LVG in evaluating EF and regional wall motion, we compared IVDSA-LVG using 30 ml of contrast medium with direct LVG in 18 patients. There was a good correlation between the two methods in determining EF (r = 0.877), and 90 % of the interpretations of regional wall motion were in agreement by the two methods. IVDSA-LVG was useful and accurate in evaluating EF and regional wall motion of the left ventricle. 3. IADSA-LVG was performed for five patients, and good quality images were obtained in many cases, even with relatively small doses (10 ml) of contrast media. These results suggested that this method may be used in cases with impaired LV function, to avoid hemodynamic derangement induced by conventional direct LVG using large doses of contrast medium. (author)

  1. Confirmation of T1-Bright Vein of Galen Aneurysm Spontaneous Thrombosis by Subtraction Magnetic Resonance Venography: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Irfan, M.; Lohman, B.; McKinney, A.M. (Dept. of Radiology/Neuroradiology, Univ. of Minnesota, Minneapolis, Minnesota (United States))

    2009-08-15

    Spontaneous thrombosis of a vein of Galen aneurysmal malformation (VOGM) is rare. We describe a 2-month-old patient with a patent VOGM and hydrocephalus, also confirmed patent at 6 months, but with subsequent lack of filling on pre-embolization catheter digital subtraction angiography (DSA) at 9 months' age. Due to the presence of T1- and T2-bright signal, noncontrast T1-weighted images (T1WI), T2-weighted images (T2WI), two-dimensional (2D) time-of-flight (TOF) magnetic resonance venography (MRV), and postcontrast T1WI were ambiguous for patency. However, subtracting the pre- from the postcontrast MRV images confirmed closure compared to subtracted images at 6 months' age. The factors contributing to thrombosis were likely a combination of a disproportionately small straight sinus, ventriculostomy, and contrast medium from DSA.

  2. NNLO jet cross sections by subtraction

    International Nuclear Information System (INIS)

    Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

    2010-06-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

  3. Digital subtraction angiography of the thoracic aorta

    International Nuclear Information System (INIS)

    Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

    1984-01-01

    Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram

  4. Digital subtraction angiography of the thoracic aorta

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

    1984-02-01

    Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.

  5. NNLO jet cross sections by subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Bolzoni, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Z. [CERN, Geneva (Switzerland)

    2010-06-15

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

  6. NNLO jet cross sections by subtraction

    CERN Document Server

    Somogyi, Gabor; Trocsanyi, Zoltan

    2010-01-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  7. Evaluation of left ventricular function using digital subtraction angiography

    International Nuclear Information System (INIS)

    Kozuka, Takahiro; Ohta, Mitsushige

    1985-01-01

    To evaluate function of the left ventricle and myocardial perfusion images, digital subtraction angiography (DSA) was performed in 45 patients with ischemic heart disease. Validity of the technique was compared with data obtained from cine left ventriculogram in all patients and 201 T1 myocardial images in 20 patients. End-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) calculated from DSA were correlated closely with those from cine left ventriculogram (r = 0.92, r = 0.94 and r = 0.86, respectively). Regional contractility at the antero-lateral wall of the left ventricle, assessed by DSA, was also correlated well with cine left ventriculogram (r = 0.75). Evaluation of the inferior wall motion showed less correlation in both procedures (r = 0.68). Phase and amplitude analysis with the same technique with radionuclide cardiac angiography was successfully applied in left ventriculogram obtained by DSA. The procedure seems to be helpful for objective evaluation of the left ventricular wall motion. Myocardial perfusion image, obtained with modified Radtke's technique, showed good coincidence with 201 T1 images. Thus, DSA is applicable for evaluation of function of the left ventricle and myocardial perfusion in patients with ischemic heart disease. (author)

  8. The Pedestrian Detection Method Using an Extension Background Subtraction about the Driving Safety Support Systems

    Science.gov (United States)

    Muranaka, Noriaki; Date, Kei; Tokumaru, Masataka; Imanishi, Shigeru

    In recent years, the traffic accident occurs frequently with explosion of traffic density. Therefore, we think that the safe and comfortable transportation system to defend the pedestrian who is the traffic weak is necessary. First, we detect and recognize the pedestrian (the crossing person) by the image processing. Next, we inform all the drivers of the right or left turn that the pedestrian exists by the sound and the image and so on. By prompting a driver to do safe driving in this way, the accident to the pedestrian can decrease. In this paper, we are using a background subtraction method for the movement detection of the movement object. In the background subtraction method, the update method in the background was important, and as for the conventional way, the threshold values of the subtraction processing and background update were identical. That is, the mixing rate of the input image and the background image of the background update was a fixation value, and the fine tuning which corresponded to the environment change of the weather was difficult. Therefore, we propose the update method of the background image that the estimated mistake is difficult to be amplified. We experiment and examines in the comparison about five cases of sunshine, cloudy, evening, rain, sunlight change, except night. This technique can set separately the threshold values of the subtraction processing and background update processing which suited the environmental condition of the weather and so on. Therefore, the fine tuning becomes possible freely in the mixing rate of the input image and the background image of the background update. Because the setting of the parameter which suited an environmental condition becomes important to minimize mistaking percentage, we examine about the setting of a parameter.

  9. Pediatric head and neck lesions: assessment of vascularity by MR digital subtraction angiography.

    Science.gov (United States)

    Chooi, Weng Kong; Woodhouse, Neil; Coley, Stuart C; Griffiths, Paul D

    2004-08-01

    Pediatric head and neck lesions can be difficult to characterize on clinical grounds alone. We investigated the use of dynamic MR digital subtraction angiography as a noninvasive adjunct for the assessment of the vascularity of these abnormalities. Twelve patients (age range, 2 days to 16 years) with known or suspected vascular abnormalities were studied. Routine MR imaging, time-of-flight MR angiography, and MR digital subtraction angiography were performed in all patients. The dynamic sequence was acquired in two planes at one frame per second by using a thick section (6-10 cm) selective radio-frequency spoiled fast gradient-echo sequence and an IV administered bolus of contrast material. The images were subtracted from a preliminary mask sequence and viewed as a video-inverted cine loop. In all cases, MR digital subtraction angiography was successfully performed. The technique showed the following: 1) slow flow lesions (two choroidal angiomas, eyelid hemangioma, and scalp venous malformation); 2) high flow lesions that were not always suspected by clinical examination alone (parotid hemangioma, scalp, occipital, and eyelid arteriovenous malformations plus a palatal teratoma); 3) a hypovascular tumor for which a biopsy could be safely performed (Burkitt lymphoma); and 4) a hypervascular tumor of the palate (cystic teratoma). Our early experience suggests that MR digital subtraction angiography can be reliably performed in children of all ages without complication. The technique provided a noninvasive assessment of the vascularity of each lesion that could not always have been predicted on the basis of clinical examination or routine MR imaging alone.

  10. Clinical evaluation of dual-energy bone removal in CT angiography of the head and neck: comparison with conventional bone-subtraction CT angiography

    International Nuclear Information System (INIS)

    Deng, K.; Liu, C.; Ma, R.; Sun, C.; Wang, X.-M.; Ma, Z.-T.; Sun, X.-L.

    2009-01-01

    Aim: To evaluate the bone-subtraction effect of dual-energy bone removal in computed tomography angiography (CTA) of the head and neck in comparison with conventional bone-subtraction CTA. Material and Methods: The study comprised 52 patients who were divided into two groups at random, and examined using dual-source CT for head and neck CTA. Dual-energy bone removal CTA and conventional bone-subtraction CTA were applied to each of the two groups, respectively. The bone subtraction was performed automatically in both methods. Vascular structures, as well as brain tissue remained visible. The subtracted images were further processed with maximum intensity projection (MIP) and volume-rendering technique (VRT) for image evaluation. Two experienced radiologists reviewed the resulting subtracted and non-subtracted volume data with respect to the delineation and detection of image quality and vascular pathology. Results: The means of the weighted CT dose index (CTDIvol) for bone-removal dual-energy CTA and conventional bone-subtraction CTA were 20.56 ± 0.01 mGy and 25.57 ± 0.56 mGy, respectively. There was a significant difference between them. The percentage of carotid and vertebral arteries and all other vessels that could be successfully assessed with these two methods were 87.8, 68, and 83%, and 93.5, 91.8, and 92.6%, respectively. There were no significant differences in the visualization of the carotid arteries; however, there were significant differences in the visualization of the vertebral arteries. Conclusion: Compared with conventional bone-subtraction CTA, dual-energy bone-removal CTA had a lower radiation dose. It eliminated most bones in the head and neck successfully; however, the bone subtraction effect around the vertebral artery was unsatisfactory. Dual-energy bone-removal CTA provides a new method for detecting vascular diseases in routine clinical work.

  11. Parallel decompositions of Mueller matrices and polarimetric subtraction

    Directory of Open Access Journals (Sweden)

    Gil J.J.

    2010-06-01

    Full Text Available From a general formulation of the physically realizable parallel decompositions of the Mueller matrix M of a given depolarizing system, a procedure for determining the set of pure Mueller matrices susceptible to be subtracted from M is presented. This procedure provides a way to check if a given pure Mueller matrix N can be subtracted from M or not. If this check is positive, the value of the relative cross section of the subtracted component is also determined.

  12. Spectral amplitude coding OCDMA using and subtraction technique.

    Science.gov (United States)

    Hasoon, Feras N; Aljunid, S A; Samad, M D A; Abdullah, Mohamad Khazani; Shaari, Sahbudin

    2008-03-20

    An optical decoding technique is proposed for a spectral-amplitude-coding-optical code division multiple access, namely, the AND subtraction technique. The theory is being elaborated and experimental results have been done by comparing a double-weight code against the existing code, Hadamard. We have proved that the and subtraction technique gives better bit error rate performance than the conventional complementary subtraction technique against the received power level.

  13. Updates to Constituent Subtraction in Heavy Ions at CMS

    CERN Document Server

    CMS Collaboration

    2018-01-01

    The latest upgrades and performance of constituent subtraction in 5.02 TeV PbPb collisions is presented. The constituent subtraction is extended through the full tracker acceptance, increasing the rapidity reach of correctly subtracted jets. A modulation in azimuthal angle is added to the subtraction, accounting for flow on an event-by-event basis and improving jet energy resolution. Closure of jet energy scale after corrections and jet energy resolution is shown for R=0.4 and R=0.8 jets, the latter for the first time in CMS Heavy-Ions.

  14. Photon Subtraction by Many-Body Decoherence

    DEFF Research Database (Denmark)

    Murray, C. R.; Mirgorodskiy, I.; Tresp, C.

    2018-01-01

    We experimentally and theoretically investigate the scattering of a photonic quantum field from another stored in a strongly interacting atomic Rydberg ensemble. Considering the many-body limit of this problem, we derive an exact solution to the scattering-induced spatial decoherence of multiple...... stored photons, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis reveals a correlated coherence-protection process in which the scattering from one excitation can shield all others from spatial decoherence. We discuss how...... this effect can be used to manipulate light at the quantum level, providing a robust mechanism for single-photon subtraction, and experimentally demonstrate this capability....

  15. NNLO jet cross sections by subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Bolzoni, P. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Trocsanyi, Z. [CERN PH-TH, on leave from University of Debrecen and Institute of Nuclear Research of HAS, H-4001 P.O.Box 51 (Hungary)

    2010-08-15

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  16. NNLO jet cross sections by subtraction

    International Nuclear Information System (INIS)

    Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

    2010-01-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  17. An evaluation of the subtraction photoshop software accuracy to detect minor changes in optical density by radiovisiography

    Directory of Open Access Journals (Sweden)

    Talaeipour AR.

    2004-06-01

    Full Text Available Statement of Problem: Subtraction is a newly presented radiography technique to detect minor density"nchanges that are not visible by conventional radiography."nPurpose: The aim of this In-vitro study was to evaluate the efficacy of photoshop subtraction software for"ndetecting minor density changes between two dental images."nMaterials and Methods: In this research, five dried human mandibles were held in fixed position while thin"naluminium sheets were superimposed on each mandible on the 1th and 2nd molar teeth regions."nA reference image, without aluminium sheet placement, was obtained from each mandible subsequently series"nconsist of 20 images with aluminium sheets, ranging from 50p. to "5Q0"x were recorded by radiovisiography"n(RVG system. Initial images were subtracted from subsequent ones by Photoshop subtraction software. The"ndifference in density between the two images at the 1st and 2nd molar sites was related to the aluminium"nsheets. The optical density of aluminium sheets was determined by densitometer."nResults: In the present study, 6.6% of the optical density changes of the minimum aluminium thickness as"n300u. could be detected by photoshop software software."nConclusion: The findings of this study showed that the accuracy of photoshop subtraction software was equal"nto that of the conventional subtraction softwares. Additionally, the accuracy of this software was proved to be"nsuitable for clinical investigations of small localized changes in alveolar bone.

  18. Evaluation of chronic periapical lesions by digital subtraction radiography by using Adobe Photoshop CS: a technical report.

    Science.gov (United States)

    Carvalho, Fabiola B; Gonçalves, Marcelo; Tanomaru-Filho, Mário

    2007-04-01

    The purpose of this study was to describe a new technique by using Adobe Photoshop CS (San Jose, CA) image-analysis software to evaluate the radiographic changes of chronic periapical lesions after root canal treatment by digital subtraction radiography. Thirteen upper anterior human teeth with pulp necrosis and radiographic image of chronic periapical lesion were endodontically treated and radiographed 0, 2, 4, and 6 months after root canal treatment by using a film holder. The radiographic films were automatically developed and digitized. The radiographic images taken 0, 2, 4, and 6 months after root canal therapy were submitted to digital subtraction in pairs (0 and 2 months, 2 and 4 months, and 4 and 6 months) choosing "image," "calculation," "subtract," and "new document" tools from Adobe Photoshop CS image-analysis software toolbar. The resulting images showed areas of periapical healing in all cases. According to this methodology, the healing or expansion of periapical lesions can be evaluated by means of digital subtraction radiography by using Adobe Photoshop CS software.

  19. Digital video subtraction fluorography (DVSF) in the diagnosis of bronchial abnormality associated with congenital heart diseases

    International Nuclear Information System (INIS)

    Sano, Tetsuya; Arisawa, Jun; Nakajima, Toru

    1990-01-01

    To assess bronchial morphology and abnormality, 14 children with congenital heart diseases including 2 postoperative patients (age, 2 m.-4 yr) were studied by digital video subtraction fluorography (DVSF) using digital subtraction and image processing system (Philips, DVI-2). This newly developed technique clearly defined bronchial anatomy in all 14 patients. Bronchial situs could be determined in all 8 patients with complex heart anomalies. Out of 8 patients with respiratory distress in this study, obvious bronchial stenosis or obstruction was found by DVSF in 5 patients. Thus, DVSF image defined anatomies of main and lobar bronchi more clearly than previous noninvasive methods. Moreover, DVSF is noninvasive and easily performed even for small infants and critically ill patients. In conclusion, DVSF may be a useful technique to assess bronchial morphology and abnormality in patients with congenital heart diseases. (author)

  20. Thallium-201 chloride dynamic analysis using thallium-201 chloride and sodium iodide-131 thyroid subtraction scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Morimoto, Setsuo; Hiraki, Yoshio; Togami, Izumi [Okayama Univ. (Japan). School of Medicine

    1984-10-01

    The mechanism of /sup 201/Tl chloride accumulation is unclear in thyroid gland and thyroid tumor. This report examines 108 patients that received thyroid scintigraphy examinations with both /sup 201/Tl chloride and sodium /sup 131/I. The patients were diagnosed clinically and histologically whenever possible. The ROI were obtained by subtraction imaging with both isotopes and by subtraction positive and negative areas of imaging. Dynamic curves were obtained for /sup 201/Tl chloride per square unit of each ROI. The dynamic curve in the radioiodide-accumulated area was examined. The data indicate that the clearance rate of /sup 201/Tl chloride (T/sub 15/) was correlated with the sodium /sup 131/I uptake rate at 24 h (r=0.70).

  1. Tomography of photon-added and photon-subtracted states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the

  2. Use of the digital subtraction angiography in the study of aortic dissecting aneurisms

    Energy Technology Data Exchange (ETDEWEB)

    Orlacchio, A; Fanucci, E; Pocek, M; Cirillo, F

    1984-01-01

    Authors on the basis of their data discuss the opportunity affered by the digital subtraction angiography (DSA) in the study of the aorta dissecting aneurisms. DSA as a consequence of the image formation and processing techniques allows the optimization of information concerning the reflux kinetics in the true and false lumen and offers a vascular mapping of the body district under study which is enough indicative to the subsequent therapy.

  3. Robotic digital subtraction angiography systems within the hybrid operating room.

    Science.gov (United States)

    Murayama, Yuichi; Irie, Koreaki; Saguchi, Takayuki; Ishibashi, Toshihiro; Ebara, Masaki; Nagashima, Hiroyasu; Isoshima, Akira; Arakawa, Hideki; Takao, Hiroyuki; Ohashi, Hiroki; Joki, Tatsuhiro; Kato, Masataka; Tani, Satoshi; Ikeuchi, Satoshi; Abe, Toshiaki

    2011-05-01

    Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery. To describe initial clinical experience with a robotic DSA system in the hybrid OR. A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation. Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement. This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

  4. Pelvic digital subtraction catheter angiography-Are routine oblique projections necessary?

    International Nuclear Information System (INIS)

    Rane, Neil; Imam, Atique; Foley, Peter; Timmons, Grace; Uberoi, Raman

    2011-01-01

    The oblique projection is used widely in imaging of the lower vascular tree. Much of the evidence justifying the oblique projection is anecdotal. This study compares the sensitivity of the anteroposterior (AP) projection alone in lower limb vascular catheter angiography to that combined with the oblique projection. 110 digitally subtracted angiograms were analysed initially on AP and subsequently on oblique views. Oblique imaging increases confidence, demonstrates stenoses not seen on AP and changes the diagnosis. This supports the use of the oblique projection in lower limb vascular interventional imaging.

  5. An automated subtraction of NLO EW infrared divergences

    Energy Technology Data Exchange (ETDEWEB)

    Schoenherr, Marek [CERN, Theoretical Physics Department, Geneva (Switzerland)

    2018-02-15

    In this paper a generalisation of the Catani-Seymour dipole subtraction method to next-to-leading order electroweak calculations is presented. All singularities due to photon and gluon radiation off both massless and massive partons in the presence of both massless and massive spectators are accounted for. Particular attention is paid to the simultaneous subtraction of singularities of both QCD and electroweak origin which are present in the next-to-leading order corrections to processes with more than one perturbative order contributing at Born level. Similarly, embedding non-dipole-like photon splittings in the dipole subtraction scheme discussed. The implementation of the formulated subtraction scheme in the framework of the Sherpa Monte-Carlo event generator, including the restriction of the dipole phase space through the α-parameters and expanding its existing subtraction for NLO QCD calculations, is detailed and numerous internal consistency checks validating the obtained results are presented. (orig.)

  6. Effects of global signal regression and subtraction methods on resting-state functional connectivity using arterial spin labeling data.

    Science.gov (United States)

    Silva, João Paulo Santos; Mônaco, Luciana da Mata; Paschoal, André Monteiro; Oliveira, Ícaro Agenor Ferreira de; Leoni, Renata Ferranti

    2018-05-16

    Arterial spin labeling (ASL) is an established magnetic resonance imaging (MRI) technique that is finding broader applications in functional studies of the healthy and diseased brain. To promote improvement in cerebral blood flow (CBF) signal specificity, many algorithms and imaging procedures, such as subtraction methods, were proposed to eliminate or, at least, minimize noise sources. Therefore, this study addressed the main considerations of how CBF functional connectivity (FC) is changed, regarding resting brain network (RBN) identification and correlations between regions of interest (ROI), by different subtraction methods and removal of residual motion artifacts and global signal fluctuations (RMAGSF). Twenty young healthy participants (13 M/7F, mean age = 25 ± 3 years) underwent an MRI protocol with a pseudo-continuous ASL (pCASL) sequence. Perfusion-based images were obtained using simple, sinc and running subtraction. RMAGSF removal was applied to all CBF time series. Independent Component Analysis (ICA) was used for RBN identification, while Pearson' correlation was performed for ROI-based FC analysis. Temporal signal-to-noise ratio (tSNR) was higher in CBF maps obtained by sinc subtraction, although RMAGSF removal had a significant effect on maps obtained with simple and running subtractions. Neither the subtraction method nor the RMAGSF removal directly affected the identification of RBNs. However, the number of correlated and anti-correlated voxels varied for different subtraction and filtering methods. In an ROI-to-ROI level, changes were prominent in FC values and their statistical significance. Our study showed that both RMAGSF filtering and subtraction method might influence resting-state FC results, especially in an ROI level, consequently affecting FC analysis and its interpretation. Taking our results and the whole discussion together, we understand that for an exploratory assessment of the brain, one could avoid removing RMAGSF to

  7. Analytical optimization of digital subtraction mammography with contrast medium using a commercial unit.

    Science.gov (United States)

    Rosado-Méndez, I; Palma, B A; Brandan, M E

    2008-12-01

    Contrast-medium-enhanced digital mammography (CEDM) is an image subtraction technique which might help unmasking lesions embedded in very dense breasts. Previous works have stated the feasibility of CEDM and the imperative need of radiological optimization. This work presents an extension of a former analytical formalism to predict contrast-to-noise ratio (CNR) in subtracted mammograms. The goal is to optimize radiological parameters available in a clinical mammographic unit (x-ray tube anode/filter combination, voltage, and loading) by maximizing CNR and minimizing total mean glandular dose (D(gT)), simulating the experimental application of an iodine-based contrast medium and the image subtraction under dual-energy nontemporal, and single- or dual-energy temporal modalities. Total breast-entrance air kerma is limited to a fixed 8.76 mGy (1 R, similar to screening studies). Mathematical expressions obtained from the formalism are evaluated using computed mammographic x-ray spectra attenuated by an adipose/glandular breast containing an elongated structure filled with an iodinated solution in various concentrations. A systematic study of contrast, its associated variance, and CNR for different spectral combinations is performed, concluding in the proposal of optimum x-ray spectra. The linearity between contrast in subtracted images and iodine mass thickness is proven, including the determination of iodine visualization limits based on Rose's detection criterion. Finally, total breast-entrance air kerma is distributed between both images in various proportions in order to maximize the figure of merit CNR2/D(gT). Predicted results indicate the advantage of temporal subtraction (either single- or dual-energy modalities) with optimum parameters corresponding to high-voltage, strongly hardened Rh/Rh spectra. For temporal techniques, CNR was found to depend mostly on the energy of the iodinated image, and thus reduction in D(gT) could be achieved if the spectral energy

  8. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA

    Energy Technology Data Exchange (ETDEWEB)

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Hamm, Bernd; Wagner, Moritz [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS Statistical Consulting, Berlin (Germany)

    2016-12-15

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p < 0.0001) with lower rates of non-diagnostic vessel segments on 2D-bSSFP-MRA (reader 1: <1 % vs. 15 %; reader 2: 1 % vs. 29 %; p < 0.05). Diagnostic performance of 2D-bSSFP-MRA and 3D-FSE-MRA across readers showed sensitivities of 89 % (214/240) vs. 70 % (168/240), p = 0.0153; specificities: 91 % (840/926) vs. 63 % (585/926), p < 0.0001; and diagnostic accuracies of 90 % (1054/1166) vs. 65 % (753/1166), p < 0.0001. 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust nonenhanced MRA technique for assessment of the calf arteries at 3 Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). (orig.)

  9. Cardiac complications of intravenous digital subtraction angiography

    International Nuclear Information System (INIS)

    Neergaard, K.; Dirksen, K.L.; Andersen, I.; Galloee, A.M.; Madsen, E.B.

    1989-01-01

    In a prospective study of 103 patients the incidence of cardiac events during intravenous digital subtraction angiography (i.v. DSA) was investigated. Of 103 patients 17 had known ischaemic heart disease. The examination was performed with an ionic contrast medium, Urografin 76% (sodium megluminediatrizoate), administered by bolus injection into the right atrium. Patients with severe cardiac disease were examined only if the procedure was considered of vital importance. Cardiac events were defined as ST-segment changes of more than 0.1 mV, changes in heart rate of more than 20%, arrhythmias and such symptoms as chest pain and dyspnoea. Ischaemic ST-segment changes during i.v. DSA were observed in approximately 20% of the patients and were not related to the presence of known ischaemic heart disease. Three patients developed angina during the procedure. Among 12 patients with known angina only one patient developed angina during the procedure. In this study chest pain was infrequent (3%), but there was a relative high frequency of ECG changes (20%) not related to patients with ischaemic heart disease only. It is concluded that there is a risk of cardiac events during i.v. DSA, but the risk is not increased in patients with known ischaemic heart disease (if they do not suffer from congestive heart failure) as compared with other patients without known ischaemic heart disease. (orig.)

  10. Diffraction, chopping, and background subtraction for LDR

    Science.gov (United States)

    Wright, Edward L.

    1988-01-01

    The Large Deployable Reflector (LDR) will be an extremely sensitive infrared telescope if the noise due to the photons in the large thermal background is the only limiting factor. For observations with a 3 arcsec aperture in a broadband at 100 micrometers, a 20-meter LDR will emit 10(exp 12) per second, while the photon noise limited sensitivity in a deep survey observation will be 3,000 photons per second. Thus the background subtraction has to work at the 1 part per billion level. Very small amounts of scattered or diffracted energy can be significant if they are modulated by the chopper. The results are presented for 1-D and 2-D diffraction calculations for the lightweight, low-cost LDR concept that uses an active chopping quaternary to correct the wavefront errors introduced by the primary. Fourier transforms were used to evaluate the diffraction of 1 mm waves through this system. Unbalanced signals due to dust and thermal gradients were also studied.

  11. Accessing the diffracted wavefield by coherent subtraction

    Science.gov (United States)

    Schwarz, Benjamin; Gajewski, Dirk

    2017-10-01

    Diffractions have unique properties which are still rarely exploited in common practice. Aside from containing subwavelength information on the scattering geometry or indicating small-scale structural complexity, they provide superior illumination compared to reflections. While diffraction occurs arguably on all scales and in most realistic media, the respective signatures typically have low amplitudes and are likely to be masked by more prominent wavefield components. It has been widely observed that automated stacking acts as a directional filter favouring the most coherent arrivals. In contrast to other works, which commonly aim at steering the summation operator towards fainter contributions, we utilize this directional selection to coherently approximate the most dominant arrivals and subtract them from the data. Supported by additional filter functions which can be derived from wave front attributes gained during the stacking procedure, this strategy allows for a fully data-driven recovery of faint diffractions and makes them accessible for further processing. A complex single-channel field data example recorded in the Aegean sea near Santorini illustrates that the diffracted background wavefield is surprisingly rich and despite the absence of a high channel count can still be detected and characterized, suggesting a variety of applications in industry and academia.

  12. NNLO jet cross sections by subtraction

    Science.gov (United States)

    Somogyi, G.; Bolzoni, P.; Trócsányi, Z.

    2010-08-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 06, 024 (2005), arXiv:hep-ph/0502226; G. Somogyi and Z. Trócsányi, (2006), arXiv:hep-ph/0609041; G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 01, 070 (2007), arXiv:hep-ph/0609042; G. Somogyi and Z. Trócsányi, JHEP 01, 052 (2007), arXiv:hep-ph/0609043] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  13. The potential for neurovascular intravenous angiography using K-edge digital subtraction angiography

    International Nuclear Information System (INIS)

    Schueltke, E.; Fiedler, S.; Kelly, M.; Griebel, R.; Juurlink, B.; LeDuc, G.; Esteve, F.; Le Bas, J.-F.; Renier, M.; Nemoz, C.; Meguro, K.

    2005-01-01

    Background: Catheterization of small-caliber blood vessels in the central nervous system can be extremely challenging. Alternatively, intravenous (i.v.) administration of contrast agent is minimally invasive and therefore carries a much lower risk for the patient. With conventional X-ray equipment, volumes of contrast agent that could be safely administered to the patient do not allow acquisition of high-quality images after i.v. injection, because the contrast bolus is extremely diluted by passage through the heart. However, synchrotron-based digital K-edge subtraction angiography does allow acquisition of high-quality images after i.v. administration of relatively small doses of contrast agent. Materials and methods: Eight adult male New Zealand rabbits were used for our experiments. Animals were submitted to both angiography with conventional X-ray equipment and synchrotron-based digital subtraction angiography. Results: With conventional X-ray equipment, no contrast was seen in either cerebral or spinal blood vessels after i.v. injection of iodinated contrast agent. However, using K-edge digital subtraction angiography, as little as 1 ml iodinated contrast agent, when administered as i.v. bolus, yielded images of small-caliber blood vessels in the central nervous system (both brain and spinal cord). Conclusions: If it would be possible to image blood vessels of the same diameter in the central nervous system of human patients, the synchrotron-based technique could yield high-quality images at a significantly lower risk for the patient than conventional X-ray imaging. Images could be acquired where catheterization of feeding blood vessels has proven impossible

  14. Use of subvoxel registration and subtraction to improve demonstration of contrast enhancement in MRI of the brain

    International Nuclear Information System (INIS)

    Curati, W.L.; Williams, E.J.; Oatridge, A.; Hajnal, J.V.; Saeed, N.; Bydder, G.M.

    1996-01-01

    To assess the potential of registration of images before and after contrast medium for improving the demonstration of contrast enhancement, we compared conventional 2 D T 1-weighted spin-echo images with precisely registered 3 D volume images and subtraction images derived from them in 2 normal subjects and 30 patients with a variety of brain disease. The volume images were registered to subvoxel accuracy using a rigid body translation and rotation, sinc interpolation and a least-squares fit; subtraction images were obtained from these. Normal contrast enhancement was demonstrated better with positionally registered volume and subtraction images than with conventional images in the meninges, ependyma, diploic veins, scalp, skin, orbit and sinuses. Abnormal enhancement was seen better in meningeal disease, multiple sclerosis and tumours as well as on follow-up studies. Subvoxel registration of images before and after contrast medium may be of considerable value in the recognition of contrast enhancement where there are small changes, or where the changes affect tissues with high or low baseline signal values. The technique also appears likely to be of value in demonstrating contrast enhancement in tissues at inferfaces and at other areas of complex anatomy, and in follow-up studies. (orig.). With 4 figs., 4 tabs

  15. Longitudinal development of subtraction performance in elementary school.

    Science.gov (United States)

    Artemenko, Christina; Pixner, Silvia; Moeller, Korbinian; Nuerk, Hans-Christoph

    2017-10-05

    A major goal of education in elementary mathematics is the mastery of arithmetic operations. However, research on subtraction is rather scarce, probably because subtraction is often implicitly assumed to be cognitively similar to addition, its mathematical inverse. To evaluate this assumption, we examined the relation between the borrow effect in subtraction and the carry effect in addition, and the developmental trajectory of the borrow effect in children using a choice reaction paradigm in a longitudinal study. In contrast to the carry effect in adults, carry and borrow effects in children were found to be categorical rather than continuous. From grades 3 to 4, children became more proficient in two-digit subtraction in general, but not in performing the borrow operation in particular. Thus, we observed no specific developmental progress in place-value computation, but a general improvement in subtraction procedures. Statement of contribution What is already known on this subject? The borrow operation increases difficulty in two-digit subtraction in adults. The carry effect in addition, as the inverse operation of borrowing, comprises categorical and continuous processing characteristics. What does this study add? In contrast to the carry effect in adults, the borrow and carry effects are categorical in elementary school children. Children generally improve in subtraction performance from grades 3 to 4 but do not progress in place-value computation in particular. © 2017 The British Psychological Society.

  16. A colorful alternative to digital subtraction

    International Nuclear Information System (INIS)

    O'Connell, W.; Ortendahl, D.; Faulkner, D.; Engelstad, B.; Okerlund, M.; Botvinick, E.; Dae, M.; Garrett, J.

    1986-01-01

    It is often useful to compare two different, but related clinical images, I1 and I2 e.g. dual isotope images of an organ, the end-diastolic and end-systolic frames of a gated blood-pool study, or T1 and T2 images from a magnetic resonance study. The authors describe a comparison technique which retains the two-dimensional nature of the image data called the polar comparison technique. This technique uses color to display the original image data. (Auth.)

  17. A case of aortitis syndrome diagnosed by digital subtraction angiography

    International Nuclear Information System (INIS)

    Tamaki, Atsushi; Sakai, Masashi; Yano, Kimio

    1984-01-01

    A 45-year-old female was admitted to our hospital with complaints of anemia, hypertension, and a dull, throbbing pain in the right side of the neck. On physical examination, a pulsating tumor in the right side of the neck and a ''to-and-fro'' murmur at the right 2nd intercostal space were noted. Laboratory tests revealed ESR 90 mm/hour and CRP 5+. Digital subtraction angiography (DSA) showed an aneurysm distal to the narrowing of the right common carotid artery, in addition to winding and narrowing of the right vertebral and the left common carotid arteries. These findings are typical of Type I aortitis syndrome. Aortogram showed aortic regurgitation (AR). Furthermore, we found the presence of HLA Bw52 and a conspicuous increase of tromboxane B 2 . Treatment involving a combination of prednisolone, azathioprine and estriol was effective, resulting in marked improvement of the patient's general condition as well as laboratory test results. In cases of aortitis syndrome combined with an aneurysm of a large artery and AR, direct opacification of the aorta with a catheter is occasionally hazardous and is difficult to perform repeatedly. DSA is useful in such circumstances because it can be performed repeatedly with little risk and it offers an image as clear as these obtained by direct injection of contrast medium in the aorta. (author)

  18. Segmentation of Moving Object Using Background Subtraction Method in Complex Environments

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2016-06-01

    Full Text Available Background subtraction is an extensively used approach to localize the moving object in a video sequence. However, detecting an object under the spatiotemporal behavior of background such as rippling of water, moving curtain and illumination change or low resolution is not a straightforward task. To deal with the above-mentioned problem, we address a background maintenance scheme based on the updating of background pixels by estimating the current spatial variance along the temporal line. The work is focused to immune the variation of local motion in the background. Finally, the most suitable label assignment to the motion field is estimated and optimized by using iterated conditional mode (ICM under a Markovian framework. Performance evaluation and comparisons with the other well-known background subtraction methods show that the proposed method is unaffected by the problem of aperture distortion, ghost image, and high frequency noise.

  19. Usefulness of multi-plane dynamic subtraction CT (MPDS-CT) for intracranial high density lesions

    Energy Technology Data Exchange (ETDEWEB)

    Takagi, Ryo; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan)

    1996-02-01

    We present a new CT technique using the high speed CT scanner in detection and evaluation of temporal and spatial contrast enhancement of intracranial high density lesions. A multi-plane dynamic subtraction CT (MPDS-CT) was performed in 21 patients with intracranial high density lesions. These lesions consisted of 10 brain tumors, 7 intracerebral hemorrhages and 4 vascular malformations (2 untreated, 2 post-embolization). Baseline study was first performed, and 5 sequential planes of covering total high density lesions were selected. After obtaining the 5 sequential CT images as mask images, three series of multi-plane dynamic CT were performed for the same 5 planes with an intravenous bolus injection of contrast medium. MPDS-CT images were reconstructed by subtracting dynamic CT images from the mask ones. MPDS-CT were compared with conventional contrast-enhanced CT. MPDS-CT images showed the definite contrast enhancement of high density brain tumors and vascular malformations which were not clearly identified on conventional contrast-enhanced CT images because of calcified or hemorrhagic lesions and embolic materials, enabling us to eliminate enhanced abnormalities with non-enhanced areas such as unusual intracerebral hemorrhages. MPDS-CT will provide us further accurate and objective information and will be greatly helpful for interpreting pathophysiologic condition. (author).

  20. A technique of scatter and glare correction for videodensitometric studies in digital subtraction videoangiography

    International Nuclear Information System (INIS)

    Shaw, C.G.; Ergun, D.L.; Myerowitz, P.D.; Van Lysel, M.S.; Mistretta, C.A.; Zarnstorff, W.C.; Crummy, A.B.

    1982-01-01

    The logarithmic amplification of video signals and the availability of data in digital form make digital subtraction videoangiography a suitable tool for videodensitometric estimation of physiological quantities. A system for this purpose was implemented with a digital video image processor. However, it was found that the radiation scattering and veiling glare present in the image-intensified video must be removed to make meaningful quantitations. An algorithm to make such a correction was developed and is presented. With this correction, the videodensitometry system was calibrated with phantoms and used to measure the left ventricular ejection fraction of a canine heart

  1. Performance of computed tomography for contrast agent concentration measurements with monochromatic x-ray beams: comparison of K-edge versus temporal subtraction

    International Nuclear Information System (INIS)

    Elleaume, H.; Charvet, A.M.; Corde, S.; Esteve, F.; Le Bas, J.F.

    2002-01-01

    We investigated the performance of monochromatic computed tomography for the quantification of contrast agent concentrations. Two subtraction methods (K-edge subtraction and temporal subtraction) were evaluated and compared theoretically and experimentally in terms of detection limit, precision and accuracy. Measurements were performed using synchrotron x-rays with Lucite phantoms (10 cm and 17.5 cm in diameter) containing iodine or gadolinium solutions ranging from 50 μg ml -1 to 5 mg ml -1 . The experiments were carried out using monochromators developed at the European Synchrotron Radiation Facility (ESRF) medical beamline. The phantoms were imaged either above and below the contrast agent K-edge, or before and after the addition of the contrast agent. Both methods gave comparable performance for phantoms less than 10 cm in diameter. For large phantoms, equivalent to a human head, the temporal subtraction is more suitable for detecting elements such as iodine, keeping a reasonable x-ray dose delivered to the phantom. A good agreement was obtained between analytical calculations, simulations and measurements. The beam harmonic content was taken into account in the simulations. It explains the performance degradation with high contrast agent concentrations. The temporal subtraction technique has the advantage of energy tunability and is well suited for imaging elements, such as iodine or gadolinium, in highly absorbing samples. For technical reasons, the K-edge method is preferable when the imaged organ is moving since the two measurements can be performed simultaneously, which is mandatory for obtaining a good subtraction. (author)

  2. Model Checking Timed Automata with Priorities using DBM Subtraction

    DEFF Research Database (Denmark)

    David, Alexandre; Larsen, Kim Guldstrand; Pettersson, Paul

    2006-01-01

    In this paper we describe an extension of timed automata with priorities, and efficient algorithms to compute subtraction on DBMs (difference bounded matrices), needed in symbolic model-checking of timed automata with priorities. The subtraction is one of the few operations on DBMs that result...... in a non-convex set needing sets of DBMs for representation. Our subtraction algorithms are efficient in the sense that the number of generated DBMs is significantly reduced compared to a naive algorithm. The overhead in time is compensated by the gain from reducing the number of resulting DBMs since...... this number affects the performance of symbolic model-checking. The uses of the DBM subtraction operation extend beyond timed automata with priorities. It is also useful for allowing guards on transitions with urgent actions, deadlock checking, and timed games....

  3. Increasing Entanglement between Gaussian States by Coherent Photon Subtraction

    DEFF Research Database (Denmark)

    Ourjoumtsev, Alexei; Dantan, Aurelien Romain; Tualle Brouri, Rosa

    2007-01-01

    We experimentally demonstrate that the entanglement between Gaussian entangled states can be increased by non-Gaussian operations. Coherent subtraction of single photons from Gaussian quadrature-entangled light pulses, created by a nondegenerate parametric amplifier, produces delocalized states...

  4. Soft-collinear factorization and zero-bin subtractions

    International Nuclear Information System (INIS)

    Chiu Juiyu; Fuhrer, Andreas; Kelley, Randall; Manohar, Aneesh V.; Hoang, Andre H.

    2009-01-01

    We study the Sudakov form factor for a spontaneously broken gauge theory using a (new) Δ-regulator. To be well defined, the effective theory requires zero-bin subtractions for the collinear sectors. The zero-bin subtractions depend on the gauge boson mass M and are not scaleless. They have both finite and 1/ε contributions and are needed to give the correct anomalous dimension and low-scale matching contributions. We also demonstrate the necessity of zero-bin subtractions for soft-collinear factorization. We find that after zero-bin subtractions the form factor is the sum of the collinear contributions minus a soft mass-mode contribution, in agreement with a previous result of Idilbi and Mehen in QCD. This appears to conflict with the method-of-regions approach, where one gets the sum of contributions from different regions.

  5. Digital Subtraction Angiography (DSA) "Road Map": An Angiographic Tool

    Science.gov (United States)

    Turski, P. A.; Stieghorst, M. F.; Strother, C. M.; Crummy, A. B.; Lieberman, R. P.; Mistretta, C. A.

    1982-12-01

    Continuous Digital subtraction combined with intraarterial injections of contrast medium permits the display of arterial structures during real time fluoroscopy. This DSA "road map" facilitates selective catheterization and has proved useful in interventional procedures.

  6. Decoupling Subtraction Conserving Full Gauge Symmetries : Particles and Fields

    OpenAIRE

    Noriyasu, OHTSUBO; Hideo, MIYATA; Department of Phycics, Kanazawa Technical College; Department of Information Science, Kanazawa Institute of Technolgy

    1984-01-01

    A new subtraction scheme (^^^) which realizes the decoupling and conserves the symmetries of full gauge group simultaneously, is proposed. One particle irreducible Green's functions subtracted by ^^^ reveal the effective low energy symmetries at -p^2≪M^2 and the full symmetries at -p^2≫M^2, where M denotes a heavy mass. Also discussed are conditions in order to carry out ^^^ under two-loop approximation.

  7. AutoDipole - Automated generation of dipole subtraction terms

    International Nuclear Information System (INIS)

    Hasegawa, K.; Uwer, P.

    2009-11-01

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  8. Developing a Model to Support Students in Solving Subtraction

    Directory of Open Access Journals (Sweden)

    Nila Mareta Murdiyani

    2013-01-01

    Full Text Available Subtraction has two meanings and each meaning leads to the different strategies. The meaning of “taking away something” suggests a direct subtraction, while the meaning of “determining the difference between two numbers” is more likely to be modeled as indirect addition. Many prior researches found that the second meaning and second strategy rarely appeared in the mathematical textbooks and teacher explanations, including in Indonesia. Therefore, this study was conducted to contribute to the development of a local instruction theory for subtraction by designing instructional activities that can facilitate first grade of primary school students to develop a model in solving two digit numbers subtraction. Consequently, design research was chosen as an appropriate approach for achieving the research aim and Realistic Mathematics Education (RME was used as a guide to design the lesson. This study involved 6 students in the pilot experiment, 31 students in the teaching experiment, and a first grade teacher of SDN 179 Palembang. The  result of this study shows that the beads string could bridge students from the contextual problems (taking ginger candies and making grains bracelets to the use of the empty number line. It also shows that the empty number line could promote students to  use different strategies (direct subtraction, indirect addition, and indirect subtraction in solving subtraction problems. Based on these findings, it is recommended to apply RME in the teaching learning process to make it more meaningful for students. Keywords: Subtraction, Design Research, Realistic Mathematics Education, The Beads String, The Empty Number Line DOI: http://dx.doi.org/10.22342/jme.4.1.567.95-112

  9. IR subtraction schemes. Integrating the counterterms at NNLO in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, Paolo; Somogyi, Gabor

    2010-06-15

    We briefly review a subtraction scheme for computing radiative corrections to QCD jet cross sections that can be defined at any order in perturbation theory. Hereafter we discuss the computational methods used to evaluate analytically and numerically the integrated counterterms arising from such a subtraction scheme. Basically these methods the Mellin-Barnes (MB) representations technique together with the harmonic summation and the sector decomposition. (orig.)

  10. IR subtraction schemes. Integrating the counterterms at NNLO in QCD

    International Nuclear Information System (INIS)

    Bolzoni, Paolo; Somogyi, Gabor

    2010-06-01

    We briefly review a subtraction scheme for computing radiative corrections to QCD jet cross sections that can be defined at any order in perturbation theory. Hereafter we discuss the computational methods used to evaluate analytically and numerically the integrated counterterms arising from such a subtraction scheme. Basically these methods the Mellin-Barnes (MB) representations technique together with the harmonic summation and the sector decomposition. (orig.)

  11. AutoDipole - Automated generation of dipole subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Uwer, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2009-11-15

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  12. Digital subtraction radiography evaluation of the bone repair process of chronic apical periodontitis after root canal treatment.

    Science.gov (United States)

    Benfica e Silva, J; Leles, C R; Alencar, A H G; Nunes, C A B C M; Mendonça, E F

    2010-08-01

    To monitor radiographically the progress of bone repair within chronic periapical lesions after root canal treatment using digital subtraction radiography (DSR). Twelve patients with 17 single-rooted teeth with chronic apical periodontitis associated with an infected necrotic pulp were selected for root canal treatment. Periapical radiographs were taken before treatment (baseline) and immediately post-treatment, 45, 90, 135 and 180 days after treatment. The radiographic protocol included the use of individualized film holders with silicone bite blocks. The six radiographic images were digitized and submitted to digital subtraction using DSR software, resulting in five subtracted images (SI). Quantitative analysis of these SI was performed using Image Tool software to assess pixel value changes, considering a step-wedge as the gold standard and a cut-off value of 128 pixels. The aim was to identify any increase or decrease in mineral density in the region of the periapical lesion. A minor decrease in mineral density at the canal filling session and a significant progressive mineral gain in the following evaluations (P < 0.001) occurred. Pairwise comparison of pixel grey values revealed that only the 180-day follow-up differed significantly from the previous SI. Digital subtraction radiography is a useful method for evaluating the progress of bone repair after root canal treatment. Noticeable mineral gain was observed approximately 90 days after root canal filling and definite bone repair after 180 days.

  13. Digital subtraction angiography for breast diseases

    International Nuclear Information System (INIS)

    Okuyama, Nobuo; Okamoto, Yasushi; Kurita, Minoru; Nonaka, Naomichi; Ozawa, Yoshiyuki; Tsurumi, Kiyohiko

    1986-01-01

    We performed digital subtraction angiography (DSA) via arteries (IA-DSA) and veins (IV-DSA) on 42 patients with breast diseases to investigate its availability. The findings by DSA in cases with breast cancer included: tumor stains, hypervascularity and tortuosity, enlarged blood vessels, encasement and pooling. Metastatic lymph nodes and daughter nodules were also recognized by DSA. In benign tumors of the breast, a tumor stain was observed only in one case of fibroadenoma; otherwise no remarkable changes were noticed. The incidence of signs in cases with breast cancer using IA-DSA was 65 % for hypervascularity, 59 % for tumor stain, 41 % for vascular tortuosity and 41 % for enlargement of vessels. IV-DSA, on the contrary, revealed less incidences. However, tumor stain was seen frequently, and hypervascularity was seldom observed. The number of signs out of the abovementioned six appearing in each case was tabulated. With IA-DSA, there were 5 signs noted in 2 cases, but the majority had fewer: 4 cases in 4 cases and only 2 signs in 4 cases. There were no signs evident in 18 % of the cases. The incidence of the appearance of signs with IV-DSA was lower: there were no signs in 36 % of the cases. Therefore, the diagnostic accuracy of IA-DSA seemed to be fairly good in comparison with that of IV-DSA. The rate of appearance of abnormal signs was also examined, according to the size of the tumors. In IA-DSA, T 1 breast cancers revealed malignant signs in 80 % of the cases, in T 2 there were such signs 75 % and 100 % of the T 3 cases exhibited malignant signs, for an overall average of 82 %. In IV-DSA, T 1 showed 33 %, T 2 showed 70 %, and T 3 , 1 out of 1 case, showed malignant signs, 64 % altogether. It was the bigger the tumor, the larger the number of signs. The smallest breast cancer that exhibited abnormality in DSA was 1.0 x 0.7 cm in size. (J.P.N.)

  14. A comparative study of additive and subtractive manufacturing for dental restorations.

    Science.gov (United States)

    Bae, Eun-Jeong; Jeong, Il-Do; Kim, Woong-Chul; Kim, Ji-Hwan

    2017-08-01

    Digital systems have recently found widespread application in the fabrication of dental restorations. For the clinical assessment of dental restorations fabricated digitally, it is necessary to evaluate their accuracy. However, studies of the accuracy of inlay restorations fabricated with additive manufacturing are lacking. The purpose of this in vitro study was to evaluate and compare the accuracy of inlay restorations fabricated by using recently introduced additive manufacturing with the accuracy of subtractive methods. The inlay (distal occlusal cavity) shape was fabricated using 3-dimensional image (reference data) software. Specimens were fabricated using 4 different methods (each n=10, total N=40), including 2 additive manufacturing methods, stereolithography apparatus and selective laser sintering; and 2 subtractive methods, wax and zirconia milling. Fabricated specimens were scanned using a dental scanner and then compared by overlapping reference data. The results were statistically analyzed using a 1-way analysis of variance (α=.05). Additionally, the surface morphology of 1 randomly (the first of each specimen) selected specimen from each group was evaluated using a digital microscope. The results of the overlap analysis of the dental restorations indicated that the root mean square (RMS) deviation observed in the restorations fabricated using the additive manufacturing methods were significantly different from those fabricated using the subtractive methods (Padditive manufacturing methods (P=.466). Similarly, no significant differences were found between wax and zirconia, the subtractive methods (P=.986). The observed RMS values were 106 μm for stereolithography apparatus, 113 μm for selective laser sintering, 116 μm for wax, and 119 μm for zirconia. Microscopic evaluation of the surface revealed a fine linear gap between the layers of restorations fabricated using stereolithography apparatus and a grooved hole with inconsistent weak scratches

  15. Quantitation of left ventricular dimensions and function by digital video subtraction angiography

    International Nuclear Information System (INIS)

    Higgins, C.B.; Norris, S.L.; Gerber, K.H.; Slutsky, R.A.; Ashburn, W.L.; Baily, N.

    1982-01-01

    Digital video subtraction angiography (DVSA) after central intravenous administration of contrast media was used in experimental animals and in patients with suspected coronary artery disease to quantitate left ventricular dimensions and regional and global contractile function. In animals, measurements of left ventricular (LV) volumes, wall thickness, ejection fraction, segmental contraction, and cardiac output correlated closely with sonocardiometry or thermodilution measurements. In patients, volumes and ejection fractions calculated from mask mode digital images correlated closely with direct left ventriculography. Global and segmental contractile function was displayed in patients by ejection shell images, stroke volume images, and time interval difference images. Central cardiovascular function was also quantitated by measurement of pulmonary transit time and calculation of pulmonary blood volume from digital fluoroscopic images. DVSA was shown to be useful and accurate in the quantitation of central cardiovascular physiology

  16. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Noise minimization

    International Nuclear Information System (INIS)

    Contillo, Adriano; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo

    2016-01-01

    Purpose: Dual-energy image subtraction represents a useful tool to improve the detectability of small lesions, especially in dense breasts. A feature it shares with all x-ray imaging techniques is the appearance of fluctuations in the texture of the background, which can obscure the visibility of interesting details. The aim of the work is to investigate the main noise sources, in order to create a better performing subtraction mechanism. In particular, the structural noise cancellation was achieved by means of a suitable extension of the dual-energy algorithm. Methods: The effect of the cancellation procedure was tested on an analytical simulation of a target with varying structural composition. Subsequently, the subtraction algorithm was also applied to a set of actual radiographs of a breast phantom exhibiting a nonuniform background pattern. The background power spectra of the outcomes were computed and compared to the ones obtained from a standard subtraction algorithm. Results: The comparison between the standard and the proposed cancellations showed an overall suppression of the magnitudes of the spectra, as well as a flattening of the frequency dependence of the structural component of the noise. Conclusions: The proposed subtraction procedure provides an effective cancellation of the residual background fluctuations. When combined with the polychromatic correction already described in a companion publication, it results in a high performing dual-energy subtraction scheme for commercial mammography units.

  17. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Noise minimization

    Energy Technology Data Exchange (ETDEWEB)

    Contillo, Adriano, E-mail: contillo@fe.infn.it; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo [Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122 Ferrara (Italy)

    2016-06-15

    Purpose: Dual-energy image subtraction represents a useful tool to improve the detectability of small lesions, especially in dense breasts. A feature it shares with all x-ray imaging techniques is the appearance of fluctuations in the texture of the background, which can obscure the visibility of interesting details. The aim of the work is to investigate the main noise sources, in order to create a better performing subtraction mechanism. In particular, the structural noise cancellation was achieved by means of a suitable extension of the dual-energy algorithm. Methods: The effect of the cancellation procedure was tested on an analytical simulation of a target with varying structural composition. Subsequently, the subtraction algorithm was also applied to a set of actual radiographs of a breast phantom exhibiting a nonuniform background pattern. The background power spectra of the outcomes were computed and compared to the ones obtained from a standard subtraction algorithm. Results: The comparison between the standard and the proposed cancellations showed an overall suppression of the magnitudes of the spectra, as well as a flattening of the frequency dependence of the structural component of the noise. Conclusions: The proposed subtraction procedure provides an effective cancellation of the residual background fluctuations. When combined with the polychromatic correction already described in a companion publication, it results in a high performing dual-energy subtraction scheme for commercial mammography units.

  18. Quantitative analysis of alveolar bone change following implant placement using intraoral radiographic subtraction

    International Nuclear Information System (INIS)

    Kimura, Hiroyuki; Kanda, Shigenobu; Tanaka, Takemasa

    2002-01-01

    The purpose of this study was to develop a procedure for quantitative analysis using intraoral radiographs of alveolar bone after placement of dental implants and to consider the validity of the method. We evaluated the ten patients (2 males and 8 females, average age: 48.4 years-old), who were treated with dental implant operation in the site of mandibular molar region, since October of 1999 until September of 2000 in Kimura Dental Clinic (Kumamoto, Japan). We evaluated the intraoral radiographs taken pre- and post- operatively and at follow-up examination. To detect alveolar bone change on radiograph, we adopted the digital subtraction method. Although the radiographs were taken under an ordinary technique with cone indicator, we did not apply the standardized technique with fixing material customized for each patient. Therefore, we used geometric correction and density compensation before subtraction. We assessed the basic statistical values (mean, variance, kurtosis and skewness) of the region of interest (ROI) of the subtracted images. Also, we noted PPD (probing pocket depth) and BOP (bleeding on probing) at each site as indicators of clinical findings and all implanted sites were classified according to the PPD or BOP, i.e. PPD increased group ''PPD (+)'' and PPD stable group ''PPD (-)'', likewise BOP positive group ''BOP (+)'' and negative group ''BOP (-)''. We considered the statistical values of ROI in each group and compared these findings. Mean and variance values of PPD (+) were higher than those of PPD (-) and there was a significant difference in mean value (p=0.031). Similarly, mean and variance values of BOP (+) were statistically higher than those of BOP (-) (p=0.041 and p=0.0087, respectively). Concerning kurtosis and skewness, there was no difference between PPD (+) and PPD (-), or between BOP (+) and BOP (-). Using our method, the radiographs taken for follow-up examination could be assessed quantitatively. It is suggested that geometric

  19. Effectiveness of digital subtraction radiography in detecting artificially created osteophytes and erosions in the temporomandibular joint

    Energy Technology Data Exchange (ETDEWEB)

    Kocasarac, Husniye Demirturk [Dept. of Comprehensive Dentistry, The University of Texas Health Science Center, San Antonio (United States); Celenk, Peruze [Dept. of Oral and Maxillofacial Radiology, Faculty of Dentistry, Ondokuz Mayis University, Samsun (Turkmenistan)

    2017-06-15

    Erosions and osteophytes are radiographic characteristics that are found in different stages of temporomandibular joint (TMJ) osteoarthritis. This study assessed the effectiveness of digital subtraction radiography (DSR) in diagnosing simulated osteophytes and erosions in the TMJ. Five intact, dry human skulls were used to assess the effectiveness of DSR in detecting osteophytes. Four cortical bone chips of varying thicknesses (0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm) were placed at the medial, central, and lateral aspects of the condyle anterior surface. Two defects of varying depth (1.0 mm and 1.5 mm) were created on the lateral, central, and medial poles of the condyles of 2 skulls to simulate erosions. Panoramic images of the condyles were acquired before and after artificially creating the changes. Digital subtraction was performed with Emago dental image archiving software. Five observers familiar with the interpretation of TMJ radiographs evaluated the images. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic accuracy of the imaging methods. The area under the ROC curve (Az) value for the overall diagnostic accuracy of DSR in detecting osteophytic changes was 0.931. The Az value for the overall diagnostic accuracy of panoramic imaging was 0.695. The accuracy of DSR in detecting erosive changes was 0.854 and 0.696 for panoramic imaging. DSR was remarkably more accurate than panoramic imaging in detecting simulated osteophytic and erosive changes. The accuracy of panoramic imaging in detecting degenerative changes was significantly lower than the accuracy of DSR (P<.05). DSR improved the accuracy of detection using panoramic images.

  20. Effectiveness of digital subtraction radiography in detecting artificially created osteophytes and erosions in the temporomandibular joint

    International Nuclear Information System (INIS)

    Kocasarac, Husniye Demirturk; Celenk, Peruze

    2017-01-01

    Erosions and osteophytes are radiographic characteristics that are found in different stages of temporomandibular joint (TMJ) osteoarthritis. This study assessed the effectiveness of digital subtraction radiography (DSR) in diagnosing simulated osteophytes and erosions in the TMJ. Five intact, dry human skulls were used to assess the effectiveness of DSR in detecting osteophytes. Four cortical bone chips of varying thicknesses (0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm) were placed at the medial, central, and lateral aspects of the condyle anterior surface. Two defects of varying depth (1.0 mm and 1.5 mm) were created on the lateral, central, and medial poles of the condyles of 2 skulls to simulate erosions. Panoramic images of the condyles were acquired before and after artificially creating the changes. Digital subtraction was performed with Emago dental image archiving software. Five observers familiar with the interpretation of TMJ radiographs evaluated the images. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic accuracy of the imaging methods. The area under the ROC curve (Az) value for the overall diagnostic accuracy of DSR in detecting osteophytic changes was 0.931. The Az value for the overall diagnostic accuracy of panoramic imaging was 0.695. The accuracy of DSR in detecting erosive changes was 0.854 and 0.696 for panoramic imaging. DSR was remarkably more accurate than panoramic imaging in detecting simulated osteophytic and erosive changes. The accuracy of panoramic imaging in detecting degenerative changes was significantly lower than the accuracy of DSR (P<.05). DSR improved the accuracy of detection using panoramic images

  1. A subtraction pipeline for automatic detection of new appearing multiple sclerosis lesions in longitudinal studies

    Energy Technology Data Exchange (ETDEWEB)

    Ganiler, Onur; Oliver, Arnau; Diez, Yago; Freixenet, Jordi; Llado, Xavier [University of Girona, VICOROB Computer Vision and Robotics Group, Girona (Spain); Vilanova, Joan C. [Girona Magnetic Resonance Center, Girona (Spain); Beltran, Brigitte [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Girona (Spain); Ramio-Torrenta, Lluis [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Multiple Sclerosis and Neuroimmunology Unit, Girona (Spain); Rovira, Alex [Vall d' Hebron University Hospital, Magnetic Resonance Unit, Department of Radiology, Barcelona (Spain)

    2014-05-15

    Time-series analysis of magnetic resonance images (MRI) is of great value for multiple sclerosis (MS) diagnosis and follow-up. In this paper, we present an unsupervised subtraction approach which incorporates multisequence information to deal with the detection of new MS lesions in longitudinal studies. The proposed pipeline for detecting new lesions consists of the following steps: skull stripping, bias field correction, histogram matching, registration, white matter masking, image subtraction, automated thresholding, and postprocessing. We also combine the results of PD-w and T2-w images to reduce false positive detections. Experimental tests are performed in 20 MS patients with two temporal studies separated 12 (12M) or 48 (48M) months in time. The pipeline achieves very good performance obtaining an overall sensitivity of 0.83 and 0.77 with a false discovery rate (FDR) of 0.14 and 0.18 for the 12M and 48M datasets, respectively. The most difficult situation for the pipeline is the detection of very small lesions where the obtained sensitivity is lower and the FDR higher. Our fully automated approach is robust and accurate, allowing detection of new appearing MS lesions. We believe that the pipeline can be applied to large collections of images and also be easily adapted to monitor other brain pathologies. (orig.)

  2. Three extensions to subtractive crosstalk reduction

    NARCIS (Netherlands)

    Smit, F.A.; Liere, van R.; Fröhlich, B.; Fröhlich, B.; Blach, R.; Liere, van R.

    2007-01-01

    Stereo displays suffer from crosstalk, an effect that reduces or even inhibits the viewer¿s ability to correctly fuse stereoscopic images. In this paper, three extensions for improved software crosstalk reduction are introduced. First, we propose a reduction method operating in CIELAB color space to

  3. Assessment of maximal myocardial perfusion by ECG-triggered digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Pijls, N.H.J.; Uijen, G.J.H.; Werf, T. van der (Katholieke Univ. Nijmegen (Netherlands). Cardiology Dept.)

    1991-01-01

    Early studies about calculation of coronary blood flow by analysis of contrast agent passage on the coronary arteriogram were reported more than 2 decades ago by Rutishauser et al. and Smith et al. Thereafter is was shown that visualization of contrast passage through the myocardium could be enhanced by ECG-triggered digital subtraction imaging and it was suggested that myocardial flow could be calculated by studying the temporal changes in contrast intensity in a myocardial region of interest (ROI) as a function of time: the time density curve (TDC). (orig./GDG).

  4. Intravenous digital subtraction angiography of transplanted kidney artery

    International Nuclear Information System (INIS)

    Tessier, J.P; Teyssou, H.; Verdier, J.P.; Tison, E.; Meyblum, J.; Marchal, M.

    1986-01-01

    Results of 351 intravenous digital subtraction angiographs (AN) of transplanted kidneys emphasized reliability of this examination for detection of renal artery stenosis. A prospective study of 219 patients (188 interpretable AN) showed significant stenosis of grafted artery in 22% of cases: 17% of the 126 patients with normal blood pressure and 34% of the 62 cases of hypertension. Digital subtraction allows, with a single injection, assessment of renal artery, nephrogram and excretory cavities, but it is not a substitute for conventional intravenous urography 1 to 2 months after grafting [fr

  5. On a gauge invariant subtraction scheme for massive quantum electrodynamics

    International Nuclear Information System (INIS)

    Abdalla, E.; Gomes, M.; Koeberle, R.

    A momentum-space subtraction scheme for massive quantum electrodynamics is proposed which respects gauge invariance, in contrast to ordinary normal product techniques. As a consequence the dependence of Green functions on the ghost mass becomes very simple and formally gauge invariant normal products of degree up to four, when subtracted according to the proposed scheme, are automatically gauge invariant. As an aplication we discuss the proof of the Adler-Bardeen theorem. Zero mass limits can be taken for Green function after the integration over intermediate states has been carried out [pt

  6. Power corrections in the N-jettiness subtraction scheme

    Energy Technology Data Exchange (ETDEWEB)

    Boughezal, Radja [High Energy Physics Division, Argonne National Laboratory,Argonne, IL 60439 (United States); Liu, Xiaohui [Department of Physics, Beijing Normal University,Beijing, 100875 (China); Center of Advanced Quantum Studies, Beijing Normal University,Beijing, 100875 (China); Center for High-Energy Physics, Peking University,Beijing, 100871 (China); Maryland Center for Fundamental Physics, University of Maryland,College Park, MD 20742 (United States); Petriello, Frank [Department of Physics & Astronomy, Northwestern University,Evanston, IL 60208 (United States); High Energy Physics Division, Argonne National Laboratory,Argonne, IL 60439 (United States)

    2017-03-30

    We discuss the leading-logarithmic power corrections in the N-jettiness subtraction scheme for higher-order perturbative QCD calculations. We compute the next-to-leading order power corrections for an arbitrary N-jet process, and we explicitly calculate the power correction through next-to-next-to-leading order for color-singlet production for both qq̄ and gg initiated processes. Our results are compact and simple to implement numerically. Including the leading power correction in the N-jettiness subtraction scheme substantially improves its numerical efficiency. We discuss what features of our techniques extend to processes containing final-state jets.

  7. Remodeling a tissue: subtraction adds insight.

    Science.gov (United States)

    Axelrod, Jeffrey D

    2012-11-27

    Sculpting a body plan requires both patterning of gene expression and translating that pattern into morphogenesis. Developmental biologists have made remarkable strides in understanding gene expression patterning, but despite a long history of fascination with the mechanics of morphogenesis, knowledge of how patterned gene expression drives the emergence of even simple shapes and forms has grown at a slower pace. The successful merging of approaches from cell biology, developmental biology, imaging, engineering, and mathematical and computational sciences is now accelerating progress toward a fuller and better integrated understanding of the forces shaping morphogenesis.

  8. Digital subtraction angiography of lower limb arteries using and automatic table translation. Feasibility. Preliminary results

    International Nuclear Information System (INIS)

    Seka, R.; Amiel, M.; Boller, A.; Chapelon, C.; Clermont, A.; Revel, D.; Pinet, F.

    1988-01-01

    Digital subtraction angiography (DSA) as a method of evaluating lower limb arteries required examination of one limb at a time up to now. Moreover repeated injections of contrast material were necessary. This problem was mainly due to the relative small image intensifier field available and to the difficulty of repositionning the patient between mask and image acquisition. The preliminary results obtained with 24 patients studied on angiographic unit equipped with: a DSA system (DG 300-CGR) using 512x512 matrix size, an angiographic table (Angix M 200) allowing an automatic sequantial translation, a removable image intensifier using a 16 inch field below the table, are reported. Thus, all those characteristics allow DSA of lower limb arteries. Only one injection of contrast material (Ioxaglate: 80 ml at 8-10 ml/second) was used per procedure. This, usually, allows good quality examination of lower limb arteries [fr

  9. Evaluation of intracranial arteriovenous malformations before and after embolization with dynamic MR digital subtraction angiography

    International Nuclear Information System (INIS)

    Chen Shuang; Feng Xiaoyuan; Baleriaux, D.; Metens, T.

    2005-01-01

    Objective: To evaluate the clinical utility and accuracy of dynamic MR digital subtraction angiography (MR-DSA) in the detection of intracranial arteriovenous malformations before and after embolization. Methods: A prospective blinded comparison of MR-DSA, 3D contrast-enhanced T 1 -weighted MR angiography (3D-CEMRA), proton-weighted imaging and conventional digital subtraction angiography (DSA) were underwent in 22 consecutive AVMs patients before and after embolization. Two readers independently interpreted images and compared with DSA images. Results: There was complete agreement between MR-DSA and DSA for classification and size of nidus before and after embolization in all cases. MR-DSA showed the modified hemodynamic features (the time of nidus, early venous enhancement delayed after carotid arteries appearance) in 17 cases, and nidus size were reduced in 13 cases (including 4 complete embolized cases) after embolization, which were 100% consistence compared with DSA. MR-DSA failed to depict 1 intranidal aneurysm and missed 1 less dilated artery and draining vein after embolization respectively, which were demonstrated clearly by 3D-CEMRA confirmed with DSA. The relatively more or less hyperintensity could be seen on proton-weighted imaging in all cases after embolization than before. Conclusion: MR-DSA is a fast, efficient, and noninvasive technique to provide hemodynamic information relevant for AVMs before and after embolization. Proton imaging is sensitive in delineation of the embolized region, MR-DSA, 3D-CEMRA and proton-weighted imaging should be combined in the evaluation and follow-up AVMs after partial embolization. (authors)

  10. Use of digital subtraction angiography for renal transplant evaluation

    International Nuclear Information System (INIS)

    Fanucci, E.; Orlacchio, A.; Pocek, M.; Svegliati, F.

    1986-01-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 6 renal allograft recipients and 3 potential renal donors. In 4 potential renal donors and in 2 allograft recipients, angiographic data were confirmed by surgery. IVDSA is a safe, accurate, easily performed, outpatient procedure; in our opinion DSA should became the procedure of choice to study vascular anatomy in renal transplant evaluation

  11. Summation and subtraction using a modified autoshaping procedure in pigeons.

    Science.gov (United States)

    Ploog, Bertram O

    2008-06-01

    A modified autoshaping paradigm (significantly different from those previously reported in the summation literature) was employed to allow for the simultaneous assessment of stimulus summation and subtraction in pigeons. The response requirements and the probability of food delivery were adjusted such that towards the end of training 12 of 48 trials ended in food delivery, the same proportion as under testing. Stimuli (outlines of squares of three sizes and colors: A, B, and C) were used that could be presented separately or in any combination of two or three stimuli. Twelve of the pigeons (summation groups) were trained with either A, B, and C or with AB, BC, and CA, and tested with ABC. The remaining 12 pigeons (subtraction groups) received training with ABC but were tested with A, B, and C or with AB, BC, and CA. These groups were further subdivided according to whether stimulus elements were presented either in a concentric or dispersed manner. Summation did not occur; subtraction occurred in the two concentric groups. For interpretation of the results, configural theory, the Rescorla-Wagner model, and the composite-stimulus control model were considered. The results suggest different mechanisms responsible for summation and subtraction.

  12. Digital subtraction angiography in the diagnosis of Fallot's tetralogy

    International Nuclear Information System (INIS)

    Ivanitskij, A.V.; Tereshkin, Ya.A.; Sobolev, A.V.; Stolyar, V.L.; Slyunyastikov, M.A.

    1995-01-01

    The authors analyze the efficacy of digital subtraction angiography (DSA) in the diagnosis of Fallot's tetralogy (FT); this method helps simplity and cut down their scope of investigations but does not deteriorate their informative value. DSA findings in 120 patients with TF are analyzed. 5 refs.; 6 figs

  13. Novel Ratio Subtraction and Isoabsorptive Point Methods for ...

    African Journals Online (AJOL)

    Purpose: To develop and validate two innovative spectrophotometric methods used for the simultaneous determination of ambroxol hydrochloride and doxycycline in their binary mixture. Methods: Ratio subtraction and isoabsorptive point methods were used for the simultaneous determination of ambroxol hydrochloride ...

  14. Determination of the kalium-subtracted total beta in food

    International Nuclear Information System (INIS)

    Liu Guofan

    1985-01-01

    A procedure for measuring the kalium-subtracted total beta in food can be applied to estimating the contamination of beta nuclides except 40 K. The procedure, calculating formula, and some experiences in practice are described in this paper. The method is simple, rapid, and very useful to food contamination monitoring

  15. Enriching Addition and Subtraction Fact Mastery through Games

    Science.gov (United States)

    Bay-Williams, Jennifer M.; Kling, Gina

    2014-01-01

    The learning of "basic facts"--single-digit combinations for addition, subtraction, multiplication, and division--has long been a focus of elementary school mathematics. Many people remember completing endless worksheets, timed tests, and flash card drills as they attempted to "master" their basic facts as children. However,…

  16. New electronic filtering technique in digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Stacul, F; Pozzi-Mucelli, R; Predonzan, F; Magnaldi, S; Godina, G

    1986-01-01

    The authors report their experience with a new electronic filtering technique in digital subtraction angiography (DSA). The principles of the technique are reported and the advantages in comparison with conventional filters are stressed (accurate and fast placement without fluoroscopic exposure). The system provided excellent results in about 900 DSA examinations.

  17. Children's Understanding of the Addition/Subtraction Complement Principle

    Science.gov (United States)

    Torbeyns, Joke; Peters, Greet; De Smedt, Bert; Ghesquière, Pol; Verschaffel, Lieven

    2016-01-01

    Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal…

  18. N-jettiness Subtractions for NNLO QCD calculations

    International Nuclear Information System (INIS)

    Gaunt, Jonathan R.; Stahlhofen, Maximilian; Tackmann, Frank J.; Walsh, Jonathan R.; California Univ., CA

    2015-05-01

    We present a subtraction method utilizing the N-jettiness observable, Τ N , to perform QCD calculations for arbitrary processes at next-to-next-to-leading order (NNLO). Our method employs soft-collinear effective theory (SCET) to determine the IR singular contributions of N-jet cross sections for Τ N → 0, and uses these to construct suitable Τ N -subtractions. The construction is systematic and economic, due to being based on a physical observable. The resulting NNLO calculation is fully differential and in a form directly suitable for combining with resummation and parton showers. We explain in detail the application to processes with an arbitrary number of massless partons at lepton and hadron colliders together with the required external inputs in the form of QCD amplitudes and lower-order calculations. We provide explicit expressions for the Τ N -subtractions at NLO and NNLO. The required ingredients are fully known at NLO, and at NNLO for processes with two external QCD partons. The remaining NNLO ingredient for three or more external partons can be obtained numerically with existing NNLO techniques. As an example, we employ our method to obtain the NNLO rapidity spectrum for Drell-Yan and gluon-fusion Higgs production. We discuss aspects of numerical accuracy and convergence and the practical implementation. We also discuss and comment on possible extensions, such as more-differential subtractions, necessary steps for going to N 3 LO, and the treatment of massive quarks.

  19. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Altaha, Mustafa A. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Rick, Manuela; Schmitt, Peter [Siemens Healthcare, Erlangen (Germany); Wintersperger, Bernd J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Toronto General Hospital, Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-03-15

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm{sup 2}) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm{sup 3}) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  20. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    International Nuclear Information System (INIS)

    Altaha, Mustafa A.; Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J.; Rick, Manuela; Schmitt, Peter; Wintersperger, Bernd J.

    2017-01-01

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm 2 ) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm 3 ) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  1. Assessment of blood supply to intracranial pathologies in children using MR digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Chooi, Weng Kong; Coley, Stuart C. [Royal Hallamshire Hospital, Department of Radiology, Sheffield (United Kingdom); Connolly, Dan J.A. [Royal Hallamshire Hospital, Department of Radiology, Sheffield (United Kingdom); Sheffield Children' s Hospital, Department of Radiology, Sheffield (United Kingdom); Griffiths, Paul D. [Royal Hallamshire Hospital, Department of Radiology, Sheffield (United Kingdom); Sheffield Children' s Hospital, Department of Radiology, Sheffield (United Kingdom); University of Sheffield, Academic Unit of Radiology, Sheffield (United Kingdom); Floor C, Royal Hallamshire Hospital, Section of Academic Radiology, Sheffield (United Kingdom)

    2006-10-15

    MR digital subtraction angiography (MR-DSA) is a contrast-enhanced MR angiographic sequence that enables time-resolved evaluation of the cerebral circulation. We describe the feasibility and technical success of our attempts at MR-DSA for the assessment of intracranial pathology in children. We performed MR-DSA in 15 children (age range 5 days to 16 years) referred for MR imaging because of known or suspected intracranial pathology that required a dynamic assessment of the cerebral vasculature. MR-DSA consisted of a thick (6-10 mm) slice-selective RF-spoiled fast gradient-echo sequence (RF-FAST) acquired before and during passage of an intravenously administered bolus of Gd-DTPA. The images were subtracted and viewed as a cine loop. MR-DSA was performed successfully in all patients. High-flow lesions were shown in four patients; these included vein of Galen aneurysmal malformation, dural fistula, and two partially treated arteriovenous malformations (AVMs). Low-flow lesions were seen in three patients, all of which were tumours. Normal flow was confirmed in eight patients including two with successfully treated AVMs, and in three patients with cavernomas. Our early experience suggests that MR-DSA is a realistic, non-invasive alternative to catheter angiography in certain clinical settings. (orig.)

  2. Assessment of blood supply to intracranial pathologies in children using MR digital subtraction angiography

    International Nuclear Information System (INIS)

    Chooi, Weng Kong; Coley, Stuart C.; Connolly, Dan J.A.; Griffiths, Paul D.

    2006-01-01

    MR digital subtraction angiography (MR-DSA) is a contrast-enhanced MR angiographic sequence that enables time-resolved evaluation of the cerebral circulation. We describe the feasibility and technical success of our attempts at MR-DSA for the assessment of intracranial pathology in children. We performed MR-DSA in 15 children (age range 5 days to 16 years) referred for MR imaging because of known or suspected intracranial pathology that required a dynamic assessment of the cerebral vasculature. MR-DSA consisted of a thick (6-10 mm) slice-selective RF-spoiled fast gradient-echo sequence (RF-FAST) acquired before and during passage of an intravenously administered bolus of Gd-DTPA. The images were subtracted and viewed as a cine loop. MR-DSA was performed successfully in all patients. High-flow lesions were shown in four patients; these included vein of Galen aneurysmal malformation, dural fistula, and two partially treated arteriovenous malformations (AVMs). Low-flow lesions were seen in three patients, all of which were tumours. Normal flow was confirmed in eight patients including two with successfully treated AVMs, and in three patients with cavernomas. Our early experience suggests that MR-DSA is a realistic, non-invasive alternative to catheter angiography in certain clinical settings. (orig.)

  3. Assessment of blood supply to intracranial pathologies in children using MR digital subtraction angiography.

    Science.gov (United States)

    Chooi, Weng Kong; Connolly, Dan J A; Coley, Stuart C; Griffiths, Paul D

    2006-10-01

    MR digital subtraction angiography (MR-DSA) is a contrast-enhanced MR angiographic sequence that enables time-resolved evaluation of the cerebral circulation. We describe the feasibility and technical success of our attempts at MR-DSA for the assessment of intracranial pathology in children. We performed MR-DSA in 15 children (age range 5 days to 16 years) referred for MR imaging because of known or suspected intracranial pathology that required a dynamic assessment of the cerebral vasculature. MR-DSA consisted of a thick (6-10 mm) slice-selective RF-spoiled fast gradient-echo sequence (RF-FAST) acquired before and during passage of an intravenously administered bolus of Gd-DTPA. The images were subtracted and viewed as a cine loop. MR-DSA was performed successfully in all patients. High-flow lesions were shown in four patients; these included vein of Galen aneurysmal malformation, dural fistula, and two partially treated arteriovenous malformations (AVMs). Low-flow lesions were seen in three patients, all of which were tumours. Normal flow was confirmed in eight patients including two with successfully treated AVMs, and in three patients with cavernomas. Our early experience suggests that MR-DSA is a realistic, non-invasive alternative to catheter angiography in certain clinical settings.

  4. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  5. Comparison of CT angiography and digital subtraction angiography in the evaluation of intracranial aneurysmal neck

    International Nuclear Information System (INIS)

    Kim, Yoo Kyung; Baik, Seung Kug; Shin, Mi Jeong; Choi, Han Yong

    2001-01-01

    To compare the usefulness of three-dimensional multislice CT angiography(CTA) and digital subtraction angiography (DSA) in the evaluation of intracranial aneurysmal neck. Nineteen patients with intracranial aneurysm (23 cases) underwent DSA and subsequent CTA. Using a multislice CT scanner and the SSD(shaded surface display) technique, clipping, cutting and the MPR technique, three-dimensional images were obtained. These were (a) external, (b) internal, from the direction of the parent artery, (c) internal, from the direction of the aneurysmal dome, and (d) an aneurysmal cutting image. The CTA findings were retrospectively compared with the DSA images. Twenty aneurysms were small and three were large. In eleven cases aneurysm neck was small, in nine it was wide, and in three it was relatively wide. For aneurysmal neck evaluation, CTA was superior to DSA in six of nine wide-neck aneurysms and all three large-sized wide-neck aneurysms. In small neck aneurysms 8 of 11 cases and in relatively wide neck all 3 cases showed similarly good images by both modalities. Of the 23 cases demonstrated by four different images, 14 cases showed the best image in internal image from parent artery direction and 6 cases showed similarly good image in both aneurysmal cutting image and internal image from parent artery direction. In the evaluation of wide neck aneurysms, 7 of 9 cases showed the best image at internal image from parent artery direction, compared with other three different images. In two cases of aneurysms, calcification was visible in the aneurysmal wall, so it was difficult to evaluate the aneurysmal neck. CTA was superior to DSA in the evaluating the intracranial aneurysmal neck. CTA maybe an additional available modality to evaluate the aneurysmal neck which is difficult to detect by the DSA. And the information of intracranial aneurysmal neck through CTA will be of value in surgical and endovascular treatment

  6. Multi-slice CT for visualization of acute pulmonary embolism: single breath-hold subtraction technique

    International Nuclear Information System (INIS)

    Wildberger, J.E.; Mahnken, A.H.; Spuentrup, E.; Guenther, R.W.; Klotz, E.; Ditt, H.

    2005-01-01

    Purpose: the purpose of our preliminary animal study was to evaluate the feasibility of a new subtraction technique for visualization of perfusion defects within the lung parenchyma in segmental and subsegmental pulmonary embolism (PE). Materials and methods: in three healthy pigs, PE were artificially induced by fresh human clot material. Within a single breath-hold, CT angiography (CTA) was performed on a 16-slice multi-slice CT scanner (SOMATOM Sensation 16; Siemens, Forchheim, Germany) before and after intravenous application of 80 mL of contrast-medium, followed by a saline chaser. Scan parameters were 120 kV and 100 mAs eff. , using a collimation of 16 x 1.5 mm and a table speed/rot. of 36 mm (pitch: 1.5; rotation time: 0.5 s). A new 3D subtraction technique was developed, which is based on automated segmentation, non-linear spatial filtering and non-rigid registration. Data were analysed using a color-encoded ''compound view'' of parenchymal enhancement and CTA information displayed in axial, coronal and sagittal orientation. Results: subtraction was technically feasible in all three data sets. The mean scan time for each series was 4.7 s, interscan delay was 14.7 s, respectively. Therefore, an average breath-hold of approximately 24 s was required for the overall scanning procedure. Downstream of occluded segmental and subsegmental arteries, perfusion defects were clearly assessable, showing lower or missing enhancement compared to normally perfused lung parenchyma. In all pigs, additional peripheral areas with triangular shaped perfusion defects were delineated, considered typical for PE. Conclusions: our initial results from the animal model studied slow that perfusion imaging of PE is feasible within a single breath-hold. It allows a comprehensive assessment of perfusion deficits as the direct proof of a pulmonary embolus, can be combined with an indirect visual quantification of the density changes in the adjacent lung tissue. (orig.)

  7. [Affine transformation-based automatic registration for peripheral digital subtraction angiography (DSA)].

    Science.gov (United States)

    Kong, Gang; Dai, Dao-Qing; Zou, Lu-Min

    2008-07-01

    In order to remove the artifacts of peripheral digital subtraction angiography (DSA), an affine transformation-based automatic image registration algorithm is introduced here. The whole process is described as follows: First, rectangle feature templates are constructed with their centers of the extracted Harris corners in the mask, and motion vectors of the central feature points are estimated using template matching technology with the similarity measure of maximum histogram energy. And then the optimal parameters of the affine transformation are calculated with the matrix singular value decomposition (SVD) method. Finally, bilinear intensity interpolation is taken to the mask according to the specific affine transformation. More than 30 peripheral DSA registrations are performed with the presented algorithm, and as the result, moving artifacts of the images are removed with sub-pixel precision, and the time consumption is less enough to satisfy the clinical requirements. Experimental results show the efficiency and robustness of the algorithm.

  8. Application of a stereoscopic digital subtraction angiography approach to blood flow analysis

    International Nuclear Information System (INIS)

    Fencil, L.E.; Doi, K.; Hoffmann, K.R.

    1986-01-01

    The authors are developing a stereoscopic digital subtraction angiographic (DSA) approach for accurate measurement of the size, magnification factor, orientation, and blood flow of a selected vessel segment. We employ a Siemens Digitron 2 and a Stereolix x-ray tube with a 25-mm tube shift. Absolute vessel sizes in each stereoscopic image are determined using the magnification factor and an iterative deconvolution technique employing the LSF of the DSA system. From data on vessel diameter and three-dimensional orientation, the effective attenuation coefficient of the diluted contrast medium can be determined, thus allowing accurate blood flow analysis in high-frame-rate DSA images. The accuracy and precision of the approach will be studied using both static and dynamic phantoms

  9. Data analysis of x-ray fluorescence holography by subtracting normal component from inverse hologram

    International Nuclear Information System (INIS)

    Happo, Naohisa; Hayashi, Kouichi; Hosokawa, Shinya

    2010-01-01

    X-ray fluorescence holography (XFH) is a powerful technique for determining three-dimensional local atomic arrangements around a specific fluorescing element. However, the raw experimental hologram is predominantly a mixed hologram, i.e., a mixture of hologram generated in both normal and inverse modes, which produces unreliable atomic images. In this paper, we propose a practical subtraction method of the normal component from the inverse XFH data by a Fourier transform for the calculated hologram of a model ZnTe cluster. Many spots originating from the normal components could be properly removed using a mask function, and clear atomic images were reconstructed at adequate positions of the model cluster. This method was successfully applied to the analysis of experimental ZnTe single crystal XFH data. (author)

  10. Research on the algorithm of infrared target detection based on the frame difference and background subtraction method

    Science.gov (United States)

    Liu, Yun; Zhao, Yuejin; Liu, Ming; Dong, Liquan; Hui, Mei; Liu, Xiaohua; Wu, Yijian

    2015-09-01

    As an important branch of infrared imaging technology, infrared target tracking and detection has a very important scientific value and a wide range of applications in both military and civilian areas. For the infrared image which is characterized by low SNR and serious disturbance of background noise, an innovative and effective target detection algorithm is proposed in this paper, according to the correlation of moving target frame-to-frame and the irrelevance of noise in sequential images based on OpenCV. Firstly, since the temporal differencing and background subtraction are very complementary, we use a combined detection method of frame difference and background subtraction which is based on adaptive background updating. Results indicate that it is simple and can extract the foreground moving target from the video sequence stably. For the background updating mechanism continuously updating each pixel, we can detect the infrared moving target more accurately. It paves the way for eventually realizing real-time infrared target detection and tracking, when transplanting the algorithms on OpenCV to the DSP platform. Afterwards, we use the optimal thresholding arithmetic to segment image. It transforms the gray images to black-white images in order to provide a better condition for the image sequences detection. Finally, according to the relevance of moving objects between different frames and mathematical morphology processing, we can eliminate noise, decrease the area, and smooth region boundaries. Experimental results proves that our algorithm precisely achieve the purpose of rapid detection of small infrared target.

  11. Diagnostic yield and accuracy of CT angiography, MR angiography, and digital subtraction angiography for detection of macrovascular causes of intracerebral haemorrhage: Prospective, multicentre cohort study

    NARCIS (Netherlands)

    C.J.J. Van Asch (Charlotte J.J.); B.K. Velthuis (Birgitta K.); G.J.E. Rinkel (Gabriël J.E.); A. Algra (Ale); G.A.P. de Kort (G. A P); T.D. Witkamp (Theo); J.C.M. De Ridder (Johanna C.M.); K.M. Van Nieuwenhuizen (Koen M.); F.-E. De Leeuw (Frank-Erik); W.J. Schonewille (Wouter); P.L.M. de Kort (Paul); D.W.J. Dippel (Diederik); T.W.M. Raaymakers (Theodora W.M.); J. Hofmeijer; M.J.H. Wermer (Marieke); H. Kerkhoff (Henk); K. Jellema (Korné); I.M. Bronner (Irene M.); M.J.M. Remmers (Michel ); H.P. Bienfait (Henri); R.J.G.M. Witjes (Ron J.G.M.); J.P. Greving (Jacoba); C.J.M. Klijn (Catharina J.M.); H.F. de Leeuw (Frank); H.B. Boogaarts; E.J. van Dijk (Ewoud); W.J. Schonewille; W.M.J. Pellikaan; C. Puppels-De Waard; P.L.M. De Kort; J.P. Peluso; J. van Tuijl (Jordie); J. Hofmeijer; F.B.M. Joosten (Frank); D.W.J. Dippel (Diederik); L. Khajeh (Ladbon); T.W.M. Raaijmakers; M.J. Wermer; M.A.A. van Walderveen (Marianne); H. Kerkhoff; E. Zock; K. Jellema (Korné); G.J. Lycklama à Nijeholt (Geert); I.M. Bronner; M.J.M. Remmers; R.J.G.M. Witjes; H.P. Bienfait; K.E. Droogh-Greve; R. Donders (Rogier); V.I.H. Kwa; T.H.C.M.L. Schreuder (Tobien H. C. M. L.); C.L. Franke (Cees); J.S. Straver; C. Jansen; S.L.M. Bakker (Stef); C.C. Pleiter (C.); M.C. Visser; C.J.J. Van Asch; B.K. Velthuis (Birgitta); G.J.E. Rinkel (Gabriel); K.M. Van Nieuwenhuizen; C.J.M. Klijn (Catharina J.M.)

    2015-01-01

    textabstractStudy question What are the diagnostic yield and accuracy of early computed tomography (CT) angiography followed by magnetic resonance imaging/angiography (MRI/MRA) and digital subtraction angiography (DSA) in patients with non-traumatic intracerebral haemorrhage? Methods This

  12. Evaluation of the pulmonary vascular bed by digital subtraction angiography

    International Nuclear Information System (INIS)

    Shikuwa, Masahiro; Asai, Sadahiro; Hara, Shiro; Yamasa, Toshihiko; Miyahara, Yoshiyuki; Hara, Kohei; Nishijima, Kyoji.

    1995-01-01

    We studied the usefulness of digital subtraction angiography for evaluating the pulmonary capillary bed. Four individuals underwent the procedure. One was a healthy volunteer and the others were patients with chronic pulmonary emphysema. During catheterization, an 8 F balloon catheter was manipulated into the right pulmonary artery. A total of 20 ml of contrast material was injected at a rate of 10 ml/sec at full inspiration. In the normal subject, the capillary bed filled homogeneously and no defect was seen. In the patients, the pulmonary artery was nearly normal, but severe defects were observed in the pulmonary capillaries. Contrast resolvability was greater with digital subtraction pulmonary angiography than with pulmonary perfusion scintigraphy or pulmonary arteriography. This technique makes possible the visual evaluation of the pulmonary capillary bed. (author)

  13. Momentum-subtraction renormalization techniques in curved space-time

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O.

    1987-10-01

    Momentum-subtraction techniques, specifically BPHZ and Zimmermann's Normal Product algorithm, are introduced as useful tools in the study of quantum field theories in the presence of background fields. In a model of a self-interacting massive scalar field, conformally coupled to a general asymptotically-flat curved space-time with a trivial topology, momentum-subtractions are shown to respect invariance under general coordinate transformations. As an illustration, general expressions for the trace anomalies are derived, and checked by explicit evaluation of the purely gravitational contributions in the free field theory limit. Furthermore, the trace of the renormalized energy-momentum tensor is shown to vanish at the Gell-Mann Low eigenvalue as it should.

  14. Momentum-subtraction renormalization techniques in curved space-time

    International Nuclear Information System (INIS)

    Foda, O.

    1987-01-01

    Momentum-subtraction techniques, specifically BPHZ and Zimmermann's Normal Product algorithm, are introduced as useful tools in the study of quantum field theories in the presence of background fields. In a model of a self-interacting massive scalar field, conformally coupled to a general asymptotically-flat curved space-time with a trivial topology, momentum-subtractions are shown to respect invariance under general coordinate transformations. As an illustration, general expressions for the trace anomalies are derived, and checked by explicit evaluation of the purely gravitational contributions in the free field theory limit. Furthermore, the trace of the renormalized energy-momentum tensor is shown to vanish at the Gell-Mann Low eigenvalue as it should

  15. Multivariate spatial condition mapping using subtractive fuzzy cluster means.

    Science.gov (United States)

    Sabit, Hakilo; Al-Anbuky, Adnan

    2014-10-13

    Wireless sensor networks are usually deployed for monitoring given physical phenomena taking place in a specific space and over a specific duration of time. The spatio-temporal distribution of these phenomena often correlates to certain physical events. To appropriately characterise these events-phenomena relationships over a given space for a given time frame, we require continuous monitoring of the conditions. WSNs are perfectly suited for these tasks, due to their inherent robustness. This paper presents a subtractive fuzzy cluster means algorithm and its application in data stream mining for wireless sensor systems over a cloud-computing-like architecture, which we call sensor cloud data stream mining. Benchmarking on standard mining algorithms, the k-means and the FCM algorithms, we have demonstrated that the subtractive fuzzy cluster means model can perform high quality distributed data stream mining tasks comparable to centralised data stream mining.

  16. Practical applications and methods in performing cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Markovic, D.M.; Withrow, S.; Moodie, D.S.

    1986-01-01

    One of the purposes of this book is to outline the utility of digital subtraction angiography (DSA) in common clinical practice. No text has dealt with the actual physical setup of the room or the patient prior and during a digital subtraction angiographic study at rest and with exercise. This chapter outlines the steps commonly used when cardiac DSA is performed on patients in the authors' laboratory. The authors have learned over the last few years the best way to prepare the patient and the equipment and it is hoped that utilizing this experience, other centers may avoid the mistakes the authors have made in the past and develop new techniques for the future

  17. Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients

    Science.gov (United States)

    Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul

    2013-01-01

    In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided. PMID:24340276

  18. Self-mixing differential vibrometer based on electronic channel subtraction

    International Nuclear Information System (INIS)

    Donati, Silvano; Norgia, Michele; Giuliani, Guido

    2006-01-01

    An instrument for noncontact measurement of differential vibrations is developed, based on the self-mixing interferometer. As no reference arm is available in the self-mixing configuration, the differential mode is obtained by electronic subtraction of signals from two (nominally equal) vibrometer channels, taking advantage that channels are servo stabilized and thus insensitive to speckle and other sources of amplitude fluctuation. We show that electronic subtraction is nearly as effective as field superposition. Common-mode suppression is 25-30 dB, the dynamic range (amplitude) is in excess of 100 μm, and the minimum measurable (differential) amplitude is 20 nm on aB=10 kHz bandwidth. The instrument has been used to measure vibrations of two metal samples kept in contact, revealing the hysteresis cycle in the microslip and gross-slip regimes, which are of interest in the study of friction induced vibration damping of gas turbine blades for aircraft applications

  19. Digital subtraction angiography in pediatric cerebrovascular occlusive disease

    International Nuclear Information System (INIS)

    Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.

    1984-01-01

    While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease

  20. Intravenous digital subtraction angiography investigation of reversible cerebral ischemia

    International Nuclear Information System (INIS)

    Pistolesi, G.F.; Maso, R.; Filosto, L.; Piovan, E.; Morgante, D.; Taddei, G.; Tonegutti, M.; Portuese, A.

    1986-01-01

    The brachio-cephalic, carotid, vertebral and intra-cranial vessels of 497 patients presenting reversible ischemic attacks (R.I.A) were evaluated with venous digital subtraction angiography (V.D.S.A.). Alterations of the vascular wall were observed in 289/497 (58.2%) patients, of whom 60% presented multiple locations (539 lesions): obstruction (12%), stenosis >50% (29%), stenosis 50%. The incidence of vascular lesions was higher (p [fr

  1. A System based on Adaptive Background Subtraction Approach for Moving Object Detection and Tracking in Videos

    Directory of Open Access Journals (Sweden)

    Bahadır KARASULU

    2013-04-01

    Full Text Available Video surveillance systems are based on video and image processing research areas in the scope of computer science. Video processing covers various methods which are used to browse the changes in existing scene for specific video. Nowadays, video processing is one of the important areas of computer science. Two-dimensional videos are used to apply various segmentation and object detection and tracking processes which exists in multimedia content-based indexing, information retrieval, visual and distributed cross-camera surveillance systems, people tracking, traffic tracking and similar applications. Background subtraction (BS approach is a frequently used method for moving object detection and tracking. In the literature, there exist similar methods for this issue. In this research study, it is proposed to provide a more efficient method which is an addition to existing methods. According to model which is produced by using adaptive background subtraction (ABS, an object detection and tracking system’s software is implemented in computer environment. The performance of developed system is tested via experimental works with related video datasets. The experimental results and discussion are given in the study

  2. Quantitative assessment of angiographic perfusion reduction using color-coded digital subtraction angiography during transarterial chemoembolization.

    Science.gov (United States)

    Wang, Ji; Cheng, Jie-Jun; Huang, Kai-Yi; Zhuang, Zhi-Guo; Zhang, Xue-Bin; Chi, Jia-Chang; Hua, Xiao-Lan; Xu, Jian-Rong

    2016-03-01

    The aim of this study was to develop a quantitative measurement of perfusion reduction using color-coded digital subtraction angiography (ccDSA) to monitor intra-procedural arterial stasis during TACE. A total number of 35 patients with hepatocellular carcinoma who had undergone TACE were enrolled into the study. Pre- and post-two-dimensional digital subtraction angiography scans were conducted with same protocol and post-processed with ccDSA prototype software. Time-contrast-intensity (CI[t]) curve was obtained by region-of-interest (ROI) measurement on the generated ccDSA image. Quantitative 2D perfusion parameters time to peak, area under the curve (AUC), maximum upslope, and contrast intensity peak (CI-Peak) derived from the ROI-based CI[t] curve for pre- and post-TACE were evaluated to assess the reduction of antegrade blood flow and tumor blush. Relationships between 2D perfusion parameters, subjective angiographic chemoembolization endpoint (SACE) scale, and clinical outcomes were analyzed. Area normalized AUC and CI-Peak revealed significant reduction after the TACE (P SACE level III and a reduction ranging from 60% to 70% was equivalent to SACE level IV. For intermediate reduction (SACE level III), better tumor response was found after TACE rather than a higher reduction (SACE level IV). ccDSA application provides an objective approach to quantify the perfusion reduction and subjectively evaluate the arterial stasis of antegrade blood flow and tumor blush caused by TACE.

  3. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

    CERN Document Server

    Somogyi, Gabor

    2013-01-01

    We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of the regularised doubly virtual contribution to the NNLO cross section becomes feasible.

  4. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

    Science.gov (United States)

    Somogyi, Gábor

    2013-04-01

    We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of fully differential rates for electron-positron annihilation into two and three jets at NNLO accuracy becomes feasible.

  5. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

    OpenAIRE

    Somogyi, Gabor

    2013-01-01

    We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of fully differential rates for electron-positron annihilation into two and three jets at NNLO accuracy becomes feasible.

  6. The Role of Bone Subtraction Computed Tomographic Angiography in Determining Intracranial Aneurysms in Non-Traumatic Subarachnoid Hemorrhage

    International Nuclear Information System (INIS)

    Kayhan, Aysegul; Koc, Osman; Keskin, Suat; Keskin, Fatih

    2014-01-01

    The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm. The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms. Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data. Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms. BSCTA is easily accessible, less time consuming, and most importantly, a non

  7. The Role of Bone Subtraction Computed Tomographic Angiography in Determining Intracranial Aneurysms in Non-Traumatic Subarachnoid Hemorrhage

    Science.gov (United States)

    Kayhan, Aysegul; Koc, Osman; Keskin, Suat; Keskin, Fatih

    2014-01-01

    Background: The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm. Objectives: The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms. Patients and Methods: Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data. Results: Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms. Conclusions: BSCTA is

  8. Digital cardiovascular imaging

    International Nuclear Information System (INIS)

    Myerowitz, P.D.; Mistretta, C.A.; Shaw, C.-G.; Van Lysel, M.S.; Swanson, D.K.; Lasser, T.A.; Dhanani, S.P.; Zarnstorff, W.C.; Vander Ark, C.R.; Dobbins, J.T.; Peppler, W.W.; Crummy, A.B.

    1982-01-01

    The authors have previously reported on real time digital fluoroscopic subtraction techniques developed in the laboratory during the past 10 years. This paper outlines basic apparatus configuration and imaging modes used for preliminary studies involving visualization of the canine and human heart. All of the techniques involve the use of real time digital subtraction processing of data from an image intensified television fluoroscopy system. Based on the configuration of the digital processing equipment a number of different imaging modalities are possible. A brief description of the apparatus and these imaging modes is given. (Auth.)

  9. Intra-arterial digital subtraction angiography (IA-DSA) with carbon dioxide

    International Nuclear Information System (INIS)

    Takeda, Toshiaki; Ido, Kunio; Yuasa, Yuji

    1988-01-01

    Intra-Arterial Digital Subtraction Angiography (IA-DSA) with Carbon Dioxide (CO 2 ) was performed on 41 patients mainly with liver or renal diseases, and its angiographic manifestation was compared with that of conventional angiography. Although the image quality of the arterial or capillary phase was inferior to that of conventional angiography with iodinated contrast media, the detectablity of arterio-venous shunting was excellent. In fact, DSA with CO 2 revealed the presence of A-V (A-P) shunt in 26 patients (26/41:63.4 % HCC, 13/15:86.7% metastatic liver tumor, 2/3:66.7 % RCC, 1/5:20 %). On the other hand, conventional angiography was able to show in only 5 cases. DSA with CO 2 will become an effective method for detecting minute arterio-venous shunting which can not be demonstrated with conventional angiography. (author)

  10. Selective intra-arterial digital subtraction angiography (IADSA) in cerebrovascular disease

    International Nuclear Information System (INIS)

    Uchino, Akira; Satoh, Yoshiyuki; Ohno, Masato

    1987-01-01

    Selective right transbrachial intra-arterial digital subtraction angiography (transbrachial selective IADSA) was successfully performed for 24 of 26 patients with known or suspected cerebrovascular disease, four of whom were outpatients. Catheterization failed in two elderly hypertensive men because of tortuosity of their brachial arteries, and in one woman whose aberrant right subclavian artery (SCA) prevented bilateral common carotid arterial (CCA) catheterizations. No complications occurred. One-hundred and ten ''excellent'' images were obtained by means of 118 injections for the 24 patients. Iopamidol, the contrast medium, was diluted to 50 % concentration with saline, then warmed to 37 deg C. Nearly all the injections of both CCAs and right vertebral arteries (VAs) were completed using 10 ml injections and a 5 ml/sec flow rate. The mean examination time for the three-vessel study was 29.4 minutes. Transbrachial selective IADSA thus proved to be a safe, useful, and relatively easy means of diagnosing cerebrovascular disease. (author)

  11. Intraarterial digital subtraction angiography after coronary bypass surgery - an alternative to coronary angiography

    International Nuclear Information System (INIS)

    Hauenstein, H.K.; Roeren, T.; Schlosser, V.; Urbani, B.

    1985-01-01

    Intraarterial digital subtraction angiography after coronary bypass surgery - an alternative to coronary angiography. Intraarterial DSA is a suitable method for early postoperative control of coronary artery bypass grafts. Small quantities of contrast media with low iodine content are injected into the aortic root. Investigations can be carried out with a routine fluoroscopic and digital equipment; additional cine-technique and analogue memory disc are not necessary. At an image rate of 3/s the bypass anastomoses can be exactly visualized in 75%, whereas diagnostic information was not sufficient in only 4% of all cases. The use of modern F-5-catheters and the nonselective injection make this method a less invasive alternative to coronary angiography. It is paticularly useful in evaluation of short- and long-term results. (orig.) [de

  12. Routine evaluation ot arteriopathies of the lower extremities by digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Stacul, F; Pozzi-Mucelli, R; Predonzan, F; Magnaldi, S; Abbona, M; Pozzi-Mucelli, R S; Dalla Palma, L

    1985-11-01

    Intravenous digital subtraction angiography (DSA) was performed in 119 patients with lower extremity ischemia using a 14'' amplifier. Four injections of contrast medium were usually necessary for a complete evaluation of this vascular region. Images of good quality were obtained in most cases; movement artifacts and a faint opacification accounted for any poor results, which occured mainly under the knee. The technique of pixel shifting turned out to be very useful to remove movement artifacts. The 'measuring field' allowed us to minimize the problem of the inhomogeneous saturation of the amplifier. In 8% of the cases an intra-arterial DSA has been performed after an unsatisfactory intravenous examination. Conventional angiography appears to be no longer necessary.

  13. Intravenous digital subtraction angiography of the lower limbs combined with field movement (2-field DSA)

    International Nuclear Information System (INIS)

    Fritschy, P.; Terrier, F.

    1988-01-01

    We evaluated a bolus-chase technique designed to reduce the volume of contrast material and to shorten examination time during intravenous digital subtraction angiography (IV-DSA) of the lower limbs. With this technique, after a single injection of contrast material, two contiguous fields can be sequentially imaged (two-field DAS) using a step translated X-ray tube. 67 patients with peripheral vascular disease were studied. All examinations provided diagnostic information, so that in no instance additional intra-arterial injections were required. With the two-field DSA only 3.49 injections were needed in the average for five fields examined in each patient, resulting in a 30% reduction of contrast agent used. (orig.) [de

  14. Digital subtraction angiography in the evaluation of chemodectomas

    International Nuclear Information System (INIS)

    Vlahos, L.; Papathanasiou, M.; Gouliamos, A.; Dimakakos, P.; Papavassiliou, C.

    1988-01-01

    During the last 2 years eleven patients with surgically confirmed chemodectomas have been investigated by means of digital subtraction angiography (DSA). Seven patients underwent i.v. DSA, which revealed eight carotid body tumours, and in the remaining four with jugulotympanic chemodectomas intra-arterial (i.a.) DSA was performed. We found i.v. DSA an easy and satisfactory method for the investigation of carotid body tumours but when glomus intravagale, tympanicum or jugulare is suspected an i.a. selective injection is required. (orig.) [de

  15. Digital subtraction angiography in the evaluation of chemodectomas

    Energy Technology Data Exchange (ETDEWEB)

    Vlahos, L.; Papathanasiou, M.; Gouliamos, A.; Dimakakos, P.; Papavassiliou, C.

    1988-05-01

    During the last 2 years eleven patients with surgically confirmed chemodectomas have been investigated by means of digital subtraction angiography (DSA). Seven patients underwent i.v. DSA, which revealed eight carotid body tumours, and in the remaining four with jugulotympanic chemodectomas intra-arterial (i.a.) DSA was performed. We found i.v. DSA an easy and satisfactory method for the investigation of carotid body tumours but when glomus intravagale, tympanicum or jugulare is suspected an i.a. selective injection is required.

  16. Clinical application of digital subtraction angiography for arterial portography

    International Nuclear Information System (INIS)

    Ohtomo, Kuni; Furui, Shigeru; Yashiro, Naofumi; Itai, Yuji; Iio, Masahiro

    1983-01-01

    Intra-arterial digital subtraction portography(IADSP) after superior mesenteric artery injection was described. A total dose of 15 ml to 20 ml of 76% contrast medium was injected at a rate of 5 ml/sec in 14 cases (9 hepatomas, 2 metastatic liver tumors, 2 cavernous hemangiomas, 1 liver cirrhosis). In 11 cases, portal venous system was clearly demonstrated by IADSP. In 8 hepatomas tumor thrombus of portal venous system could be ruled out by IADSP and embolization therapy was carried out. IADSP was also useful for demonstrating esophageal varix and splenorenal shunt. (author)

  17. A subtractive approach to interior intrusion detection system design

    International Nuclear Information System (INIS)

    Sons, R.J.; Graham, R.H. Jr.

    1986-01-01

    This paper discusses the subtractive approach to interior intrusion detection system design which assumes that all sensors are viable candidates until they are subjected to the constraints imposed by a particular facility. The constraints are determined by a sequence of questions concerning parameters such as threat definition, facility description and operation, environment, assets to be protected, security system capabilities, and cost. As a result of the questioning, some sensors will be eliminated from the candidate list, and the ''best'' set of sensors for the facility will remain. This form of questioning could be incorporated into an expert system aiding future intrusion detection system designs

  18. Digital subtraction angiography in head and neck radiology

    International Nuclear Information System (INIS)

    Carmody, R.F.; Seeger, J.F.; Smith, R.L.; Horsley, W.W.; Miller, R.W.

    1984-01-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally. (orig.)

  19. Digital subtraction angiography in head and neck radiology

    Energy Technology Data Exchange (ETDEWEB)

    Carmody, R F; Seeger, J F; Smith, R L; Horsley, W W; Miller, R W

    1984-07-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally.

  20. Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

    International Nuclear Information System (INIS)

    Hyare, Harpreet; Desigan, Sharmini; Nicholl, Helen; Guiney, Michael J.; Brookes, Jocelyn A.; Lees, William R.

    2006-01-01

    Purpose: Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease. Materials and methods: A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram. Results: Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively. Conclusion: Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients

  1. A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

    International Nuclear Information System (INIS)

    Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung

    2014-01-01

    Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

  2. A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung [Yonsei University, Wonju (Korea, Republic of)

    2014-06-15

    Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

  3. Diagnosis and evaluation of diseases of the hand by intravenous digital subtraction angiography done by an improved method

    International Nuclear Information System (INIS)

    Minakuchi, Kazuo; Nakamura, Kenji; Kudoh, Hiroaki; Takashima, Sumio; Manabe, Takao; Kaminoh, Toshio; Onoyama, Yasuto

    1988-01-01

    Twenty patients with various diseases of the hand were studied by intravenous digital subtraction angiography (IV-DSA). We used clay preparation as a compensatory filter to improve the radiological conditions and increased local circulation by use of a hot compress. By IV-DSA done in this way, excellent or good images of the carpal arteries were obtained in 21 of 23 hands examined (91%). For the metacarpal region, images were excellent or good for 13 hands (57%), and for the digital region, for 4 (17%). The arteries of the hand could be seen in all studies, although sometimes the image was poor. Further improvements of images by IV-DSA should make it possible to use IV-DSA for screening and follow-up studies of many parts of the body. (author)

  4. [sup 99m]Tc-RBC subtraction scintigraphy; Assessmet of bleeding site and rate

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Syoichi; Tonami, Syuichi; Yasui, Masakazu; Kuranishi, Makoto; Sugishita, Kouki; Nakamura, Mamoru (Toyama Medical and Pharmaceutical Univ. (Japan). Hospital)

    1994-03-01

    Sequential abdominal scintigrams with [sup 99m]Tc-labelled red blood cells (RBC) were subtracted for observing a site of gastrointestinal bleeding and calculating the bleeding rate. This method is technically very easy and can detect the site of bleeding with the minimum rate, as low as 0.2 ml/min., in a phantom experiment. In 23 cases with final diagnosis of gastrointestinal bleeding, conventional non-subtraction scintigraphy detected only 30% (7/23), but subtraction scintigraphy detected 61% (14/23). It was concluded that subtraction scintigraphy had higher sensitivity than conventional scintigraphy for early diagnosing bleeding. A combination of non-subtraction and subtraction scintigraphy is recommended to detect a site of gastrointestinal bleeding in a clinical setting. (author).

  5. Comparison of conventional panoramic radiography and panoramic digital subtraction radiography in detection of simulated lesions of mandibular condyle

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2008-12-01

    Full Text Available "n  "nBackground and Aim: Digital subtraction Radiography (DSR is a method of accurate assessing condylar head changes. several studies have been carried out in applying DSR in dentistry, however there is a few number of studies in efficacy of DSR method in assesment of condylar head changes, The aim of this study was to compare panoramic radiography and DSR detecting simulated lesions of the mandibular condyl. "nMaterials and Methods: this was a process reaserch study, in which two dry human skulls with no obvious temporomandibular joint pathology were used. Osteophytic lesions were simulated using three sizes of bone chips that were placed on the medial portion of anterior and superolateral aspects of the condyle. Osteolytic lesions were simulated making 1 and 2 mm holes using round burr in the central portion of anterior aspect and Lateral pole of the condyle. Panoramic radiographs were prepared with and without the lesions in place. These paired radiographs were digitized and digital- subtraction images of the original panoramic images were obtained. Eight observers evaluated 155 images of each modality for the presence or absence and the type of simulated lesions of the mandibular condyle. Sensitivity, specificity, reliability and measure of agreement were analyzed using kappa test and crossed tables and qualitative variables were assess by chi-square and fisher's Exact test. "nResults: Specificity of panoramic and DSR methods were 15.4% and 66.7% respectively. Sensitivity of panoramic and DSR methods were 61.1% and 80.6% for osteophytic lesions and 37.5% and 83.3% for Osteolytic lesions. The percentage of correct decisions made in DSR method was significantly more than conventional panoramic method (82.6% vs 41.9% (p<0.0001. "nConclusion: Based on the results of this study digital subtraction technique was significantly more accurate than the panoramic radiographs in detection of simulated lesions of the mandibular condyle.

  6. Qualitative and quantitative measurement of human brain activity using pixel subtraction algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Myoung; Jeong, Gwang Woo; Kim, Hyung Joong; Cho, Seong Hoon; Kang, Heoung Keun; Seo, Jeong Jin; Park, Seung Jin [School of Medicine, Chonnam National Univ., Kwangju (Korea, Republic of)

    2004-08-01

    To develop an automated quantification program, which is called FALBA (Functional and Anatomical Labeling of Brain Activation), and to provide information on the brain centers, brain activity (%) and hemispheric lateralization index on the basis of a brain activation map obtained from functional MR imaging. The 3-dimensional activation MR images were processed by a statistical parametric mapping program (SPM99, The Wellcome Department of Cognitive Neurology, University College London, UK) and MRIcro software (www.micro.com). The 3-dimensional images were first converted into 2-dimensional sectional images, and then overlapped with the corresponding T1-weighted images. Then, the image dataset was extended to -59 mm to 83 mm with a 2 mm slice-gap, giving 73 axial images. By using a pixeI subtraction method, the differences in the R, G, B values between the T1-weighted images and the activation images were extracted, in order to produce black and white (B/W) differentiation images, in which each pixel is represented by 24-bit R, G, B true colors. Subsequently, another pixel differentiation method was applied to two template images, namely one functional and one anatomical index image, in order to generate functional and anatomical differentiation images containing regional brain activation information based on the Brodmann's and anatomical areas, respectively. In addition, the regional brain lateralization indices were automatically determined, in order to evaluate the hemispheric predominance, with the positive (+) and negative (-) indices showing left and right predominance, respectively. The manual counting method currently used is time consuming and has limited accuracy and reliability in the case of the activated cerebrocortical regions. The FALBA program we developed was 240 times faster than the manual counting method: -10 hours for manual accounting and -2.5 minutes for the FALBA program using a Pentium IV processor. Compared with the FALBA program, the

  7. Qualitative and quantitative measurement of human brain activity using pixel subtraction algorithm

    International Nuclear Information System (INIS)

    Lee, Jin Myoung; Jeong, Gwang Woo; Kim, Hyung Joong; Cho, Seong Hoon; Kang, Heoung Keun; Seo, Jeong Jin; Park, Seung Jin

    2004-01-01

    To develop an automated quantification program, which is called FALBA (Functional and Anatomical Labeling of Brain Activation), and to provide information on the brain centers, brain activity (%) and hemispheric lateralization index on the basis of a brain activation map obtained from functional MR imaging. The 3-dimensional activation MR images were processed by a statistical parametric mapping program (SPM99, The Wellcome Department of Cognitive Neurology, University College London, UK) and MRIcro software (www.micro.com). The 3-dimensional images were first converted into 2-dimensional sectional images, and then overlapped with the corresponding T1-weighted images. Then, the image dataset was extended to -59 mm to 83 mm with a 2 mm slice-gap, giving 73 axial images. By using a pixeI subtraction method, the differences in the R, G, B values between the T1-weighted images and the activation images were extracted, in order to produce black and white (B/W) differentiation images, in which each pixel is represented by 24-bit R, G, B true colors. Subsequently, another pixel differentiation method was applied to two template images, namely one functional and one anatomical index image, in order to generate functional and anatomical differentiation images containing regional brain activation information based on the Brodmann's and anatomical areas, respectively. In addition, the regional brain lateralization indices were automatically determined, in order to evaluate the hemispheric predominance, with the positive (+) and negative (-) indices showing left and right predominance, respectively. The manual counting method currently used is time consuming and has limited accuracy and reliability in the case of the activated cerebrocortical regions. The FALBA program we developed was 240 times faster than the manual counting method: -10 hours for manual accounting and -2.5 minutes for the FALBA program using a Pentium IV processor. Compared with the FALBA program, the manual

  8. Comparison of spiral CT angiography with conventional digital subtraction angiography in the evaluation of renal transplant donors: a pilot study

    International Nuclear Information System (INIS)

    Chu, C.; Young, N.; Lau, H.

    2001-01-01

    Conventional digital subtraction renal arteriography (IA-DSA) has been traditionally used as the preoperative imaging modality for assessment of renal vascular anatomy for renal transplant donors. This study evaluates the potential use of spiral CT angiography in replacing IA-DSA in the preoperative assessment of this group of patients. Seven patients underwent both spiral CT angiography and IA-DSA between October 1997 and April 1998. It is concluded that spiral CT angiography can demonstrate the number, length and location of renal arteries and it is suggested that spiral CT angiography can potentially replace IA-DSA in the preoperative assessment of renal donors. Copyright (2001) Blackwell Science Pty Ltd

  9. Digital subtraction CT angiography for the detection of posterior inferior cerebellar artery aneurysms: comparison with digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Guo Zhong; Luo, Song; Zhou, Chang Sheng; Zhang, Long Jiang; Lu, Guang Ming [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China)

    2017-09-15

    To evaluate the diagnostic accuracy of digital subtraction CT angiography (DS-CTA) in detecting posterior inferior cerebellar artery (PICA) aneurysms with digital subtraction angiography (DSA) as reference standard. A total of 115 patients, including 56 patients diagnosed with PICA aneurysms by CTA or DSA and 59 non-PICA-aneurysm patients were included in this retrospective study. All patients underwent DS-CTA and DSA. The site of PICA aneurysms and the pattern of haemorrhage were analysed. Sensitivity and specificity of DS-CTA without and with combining haemorrhage pattern in diagnosing PICA aneurysms were evaluated on a per patient and per aneurysm basis with DSA. Of 115 patients, 56 patients (48.7%) had 61 PICA aneurysms (size range, 1.1-13.5 mm; mean size, 4.9 ± 2.8 mm) on DSA. The sensitivity and specificity in depicting PICA aneurysms were 89.3% and 96.6% on a per patient basis and 90.2% and 93.4% on a per aneurysm basis, while the corresponding values were 94.6% and 96.6% on a per patient basis and 95.1% and 93.4% on a per aneurysm basis when combining with haemorrhage site. DS-CTA has a high sensitivity and specificity in detecting PICA aneurysms compared with DSA. It may be helpful for clinical diagnosis of PICA aneurysms to combine with haemorrhage sites. (orig.)

  10. Combined nuclear and digital subtraction contrast arthrography in painful knee prosthesis

    International Nuclear Information System (INIS)

    Namasivayam, J.; Forrester, A.; Poon, F.W.; Cuthbert, G.F.; McKillop, J.H.; Bryan, A.S.

    1992-01-01

    The evaluation of a painful knee prosthesis remains a difficult problem for both orthopaedic surgeons and radiologists. We have compared digital subtraction arthrography with nuclear-arthrography in 7 patients with a painful knee prosthesis. Three patients showed a loose tibial component, demonstrated by both digital subtraction and nuclear arthrography. All 3 underwent revision of their prosthesis. One patient had an equivocal digital subtraction arthrogram and negative nuclear arthrogram, while both studies were negative in the 3 remaining patients. Nuclear arthrography is a simple procedure and can provide useful additional information when combined with digital subtraction arthrography. (orig.)

  11. A digital subtraction radiography based tool for periodontal bone resorption analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schiabel, Homero; Rodrigues, Eveline B., E-mail: homero@sc.usp.br [University of Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Dept. of Electrical Engineering; Rubira-Bullen, Izabel R.F. [University of Sao Paulo (USP), Bauru, SP (Brazil). Bauru Dentistry School

    2011-07-01

    The aim of this paper was to describe an aided diagnosis scheme for periodontal bone resorption so that the dentist can make an early diagnosis of the periodontal disease and establish the best treatment plan to increase the success of healing. Three ways of displaying the results are provided: qualitative, simple quantitative and colored-percentage quantitative views. A total of 72 pairs of in vitro radiographic images were used. The main procedure registers the images perspective projection aimed to align them in rotation and translation, and is followed by the application of a contrast correction technique. The results from the subtraction were evaluated firstly by the comparison between the actual and the digital sizes corresponding to the holes made by drills in phantoms. The mean error was 4.2%. The method was also applied to actual tooth radiographic images and could detect clearly the effect of treatment of periodontal diseases. It is dependent on the reproducibility of the process of radiographs acquisition and digitization, but the calculated mean error allows to conclude its better efficacy compared to usual procedures in this field. (author)

  12. Developmental venous anomalies: appearance on whole-brain CT digital subtraction angiography and CT perfusion

    International Nuclear Information System (INIS)

    Hanson, Eric H.; Roach, Cayce J.; Ringdahl, Erik N.; Wynn, Brad L.; DeChancie, Sean M.; Mann, Nathan D.; Diamond, Alan S.; Orrison, William W.

    2011-01-01

    Developmental venous anomalies (DVA) consist of dilated intramedullary veins that converge into a large collecting vein. The appearance of these anomalies was evaluated on whole-brain computed tomography (CT) digital subtraction angiography (DSA) and CT perfusion (CTP) studies. CT data sets of ten anonymized patients were retrospectively analyzed. Five patients had evidence of DVA and five age- and sex-matched controls were without known neurovascular abnormalities. CT angiograms, CT arterial-venous views, 4-D CT DSA and CTP maps were acquired on a dynamic volume imaging protocol on a 320-detector row CT scanner. Whole-brain CTP parameters were evaluated for cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT), and delay. DSA was utilized to visualize DVA anatomy. Radiation dose was recorded from the scanner console. Increased CTP values were present in the DVA relative to the unaffected contralateral hemisphere of 48%, 32%, and 26%; and for the control group with matched hemispheric comparisons of 2%, -10%, and 9% for CBF, CBV, and MTT, respectively. Average effective radiation dose was 4.4 mSv. Whole-brain DSA and CTP imaging can demonstrate a characteristic appearance of altered DVA hemodynamic parameters and capture the anomalies in superior cortices of the cerebrum and the cerebellum. Future research may identify the rare subsets of patients at increased risk of adverse outcomes secondary to the altered hemodynamics to facilitate tailored imaging surveillance and application of appropriate preventive therapeutic measures. (orig.)

  13. A digital subtraction radiography based tool for periodontal bone resorption analysis

    International Nuclear Information System (INIS)

    Schiabel, Homero; Rodrigues, Eveline B.; Rubira-Bullen, Izabel R.F.

    2011-01-01

    The aim of this paper was to describe an aided diagnosis scheme for periodontal bone resorption so that the dentist can make an early diagnosis of the periodontal disease and establish the best treatment plan to increase the success of healing. Three ways of displaying the results are provided: qualitative, simple quantitative and colored-percentage quantitative views. A total of 72 pairs of in vitro radiographic images were used. The main procedure registers the images perspective projection aimed to align them in rotation and translation, and is followed by the application of a contrast correction technique. The results from the subtraction were evaluated firstly by the comparison between the actual and the digital sizes corresponding to the holes made by drills in phantoms. The mean error was 4.2%. The method was also applied to actual tooth radiographic images and could detect clearly the effect of treatment of periodontal diseases. It is dependent on the reproducibility of the process of radiographs acquisition and digitization, but the calculated mean error allows to conclude its better efficacy compared to usual procedures in this field. (author)

  14. Developmental venous anomalies: appearance on whole-brain CT digital subtraction angiography and CT perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Eric H. [Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); University of Nevada Las Vegas, Department of Health Physics and Diagnostic Sciences, 4505 Maryland Parkway, Box 453037, Las Vegas, NV (United States); Amigenics, Inc, Las Vegas, NV (United States); Roach, Cayce J. [Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); University of Nevada Las Vegas, School of Life Sciences, Las Vegas, NV (United States); Ringdahl, Erik N. [University of Nevada Las Vegas, Department of Psychology, Las Vegas, NV (United States); Wynn, Brad L. [Family Medicine Spokane, Spokane, WA (United States); DeChancie, Sean M.; Mann, Nathan D. [Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); Diamond, Alan S. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); Orrison, William W. [Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); University of Nevada Las Vegas, Department of Health Physics and Diagnostic Sciences, 4505 Maryland Parkway, Box 453037, Las Vegas, NV (United States); CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); University of Nevada School of Medicine, Department of Medical Education, Reno, NV (United States)

    2011-05-15

    Developmental venous anomalies (DVA) consist of dilated intramedullary veins that converge into a large collecting vein. The appearance of these anomalies was evaluated on whole-brain computed tomography (CT) digital subtraction angiography (DSA) and CT perfusion (CTP) studies. CT data sets of ten anonymized patients were retrospectively analyzed. Five patients had evidence of DVA and five age- and sex-matched controls were without known neurovascular abnormalities. CT angiograms, CT arterial-venous views, 4-D CT DSA and CTP maps were acquired on a dynamic volume imaging protocol on a 320-detector row CT scanner. Whole-brain CTP parameters were evaluated for cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT), and delay. DSA was utilized to visualize DVA anatomy. Radiation dose was recorded from the scanner console. Increased CTP values were present in the DVA relative to the unaffected contralateral hemisphere of 48%, 32%, and 26%; and for the control group with matched hemispheric comparisons of 2%, -10%, and 9% for CBF, CBV, and MTT, respectively. Average effective radiation dose was 4.4 mSv. Whole-brain DSA and CTP imaging can demonstrate a characteristic appearance of altered DVA hemodynamic parameters and capture the anomalies in superior cortices of the cerebrum and the cerebellum. Future research may identify the rare subsets of patients at increased risk of adverse outcomes secondary to the altered hemodynamics to facilitate tailored imaging surveillance and application of appropriate preventive therapeutic measures. (orig.)

  15. Describable ability of blood vessels in head and neck by intravenous digital subtraction angiography

    International Nuclear Information System (INIS)

    Minakuchi, Kazuo; Takada, Keiji; Nakamura, Kenji

    1989-01-01

    Ninety-four patients with various symptoms of the head and neck were studied by intravenous digital subtraction angiography (IV-DSA). Abnormal findings were obesrved in 12 patients; one with aneurysm in the left internal carotid artery, and 11 with obstruction in the right middle cerebral artery (2), the right internal carotid artery (one), the left subclavian artery (one), the right vertebral artery (6), and the left vertebral artery (one). Motion artifacts were observed in 2 patients. The vertebral arteries were bilaterally equal in size in 42%, and the left vertebral artery was bigger than the right one in 38%. The superior sagittal dural sinus was clearly imaged in 94%. The incidence of excellent images was higher in the right sided than the left sided vein -- 85% vs 50% for the transverse dural sinus, 84% vs 54% for the sigmoid dural sinus, and 88% vs 57% for the jugular vein. Sites of excellent images were all of the dural sinuses and veins (37 cases), confined to the right side (37), confined to the left side (8), and undefined (12). (N.K.)

  16. Analysis of digital subtraction angiography for estimating flow reserve in critical coronary artery stenosis

    International Nuclear Information System (INIS)

    Kotoku, Shinya; Matsuzaki, Masunori; Otani, Nozomi

    1988-01-01

    To assess the accuracy of digital subtraction angiography in evaluating coronary flow reserve in cases with critical coronary artery stenosis, time-density curves were obtained from digital subtraction coronary angiograms in the myocardial region of interest. Time to peak contrast (TPC) and time constant of the washout exponential curve (T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty (PTCA). All patients had normal left ventricular ejection fraction (59±7%) and 201 Tl myocardial images at rest. The values of TPC and T were significantly shortened from 5.4±1.3 to 4.5±1.0 sec (p<0.02) and from 10.9±3.8 to 5.3±1.3 sec (p<0.001) after PTCA, respectively. However, in 9 patients TPC values were approximately the same before and after PTCA. In five experimental dogs with critical circumflex coronary artery stenosis, coronary flow (CF; Doppler flowmeter) and systolic thickening of the posterior wall (by sonomicrometry) at rest did not differ from those of the controls. However, contrast media-induced reactive hyperemia was markedly attenuated, accompanied by a significant increase in T (7.7±4.5 vs 15.8±10.9 sec, p<0.01) and totally unchanged TPC (both 6.8 sec). With simultaneous tracings of CF and time-density curves, TPC and washout phases corresponded with contrast-induced transient CF reduction and hyperemic phases, respectively. We concluded that T may be more sensitive for estimating CF maintained nearly normal, e.g., in patients with stable effort angina pectoris having normal left ventricular wall motion at rest. (author)

  17. Analysis of digital subtraction coronary angiography for estimation of flow reserve in critical coronary stenosis

    International Nuclear Information System (INIS)

    Kohtoku, Shinya

    1988-01-01

    To examine the accuracy of digital subtraction angiographic assessment of coronary flow reserve in critical coronary stenosis, time-density curve was obtained from digital subtraction coronary angiograms for myocardial region of interest. Time to peak contrast(TPC) and time constant of the washout exponential curve(T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty(PTCA). All patients had normal left ventricular ejection fraction (59 ± 7 %) and Tl 201 myocardial image at rest. The values of TPC and T were significantly shortened from 5.4 ± 1.3 to 4.5 ± 1.0 sec (p < 0.02) and from 10.9 ± 3.8 to 5.3 ± 1.3 sec(p < 0.001) after PTCA, respectively. However, in 9 of all patients TPC after PTCA showed approximately the same valued as those before PTCA. In 5 experimental dogs with critical circumflex stenosis, coronary flow(CF;Doppler flow meter) and systolic thickning of the posterior wall(by sonomicrometry) at rest were not different from control, however, contrast media-induced reactive hyperemia was markedly attenuated, accompanied with a significant of T (7.7 ± 4.5 vs 15.8 ± 10.9 sec, p < 0.01) and completely unchanged TPC (both 6.8 sec). With simultaneous tracing of CF and time-density curve, TPC and washout phase corresponded with contrast-induced transient CF reduction and hyperemic phase, respectively. We conclude that T might be more sensitive for estimation of CF is maintained almost normal, such as patients with stable effort angina pectoris having normal left ventricular wall motion at rest. (author)

  18. Double-nuclide subtraction scintiscanning of the pancreas

    International Nuclear Information System (INIS)

    Streithoff, E.C.

    1978-01-01

    The paper intends to find out if there is a correlation between clinical pancreas diagnoses and diagnoses by subtraction scintiscanning; furthermore, the findings of scintiscanning are compared with those of radiological and sonographic methods. In order to get a picture of the efficiency of the methods applied, not only their accuracy is determined but also their validity sum and validity product. The best results are achieved here with angiography, ERCP, and sonography. In the case of pancreatic scintiscanning, an optimal result well above the international standard is only obtained for sensitivity. On the basis of these results, the indications for an optimal and useful application of pancreatic scintiscanning are determined. (orig./AJ) [de

  19. Background subtraction system for pulsed neutron logging of earth boreholes

    International Nuclear Information System (INIS)

    Hopkinson, E.C.

    1977-01-01

    A neutron generator in well logging instrument is pulsed 100 times having a time between pulses of 1400 microseconds. This is followed by an off period of four cycles wherein 2800 microseconds is allowed for capture radiation to decay to an insignificant level and the remaining 2800 microseconds is used to measure background radiation. This results in the neutron source being disabled four pulses after every hundred pulses of operation, or approximately a 4 percent loss of neutron output. A first detector gate is open from 400 to 680 microseconds and a second detector gate is open from 700 to 980 microseconds. During the 100 cycles, each of the gates is thus open for 280 microseconds times 100 for a total of 28,000 microseconds. By scaling the gate count rate by a factor of 10, the background is subtracted directly

  20. Thallium-technetium-subtraction scintigraphy in secondary hyperparathyroidism

    International Nuclear Information System (INIS)

    Adalet, I.; Hawkins, T.; Clark, F.; Wilkinson, R.

    1994-01-01

    Between 1983 and 1992 thallium-technetium subtraction scintigraphy (TTS) was performed on 74 patients with clinical and biochemical evidence of hyperparathyroidism. Twenty-five of the 53 investigations since 1988 were conducted on patients with renal failure with a suspicion of secondary hyperparathyroidism. In a retrospective study we have evaluated radioisotope scintigraphy for patients with adenoma and for renal failure patients with possible parathyroid hyperplasia. Thirty of 74 patients underwent neck exploration. Scintigraphy detected 17 of 24 parathyroid adenomas (sensitivity 71%). In contrast, in six renal patients who came to operation, scintigraphy localised only 5 of 20 hyperplastic parathyroid glands (sensitivity 25%) and in one renal patient we localised a parathyroid adenoma. A review of the literature shows low detection rates for hyperplasia by TTS to be a common observation. Based on these findings a rational approach is offered for parathyroid localisation in renal patients prior to neck exploration. (orig.)

  1. A subtraction and 3D display program for the assessment of pulmonary embolism in SPECT V/Q scans

    International Nuclear Information System (INIS)

    Barnden, Leighton; Badger, Daniel P.

    2009-01-01

    Full text: There is interest in whether SPECT can improve the detection of pulmonary emboli with ventilation/perfusion (V /Q) scanning compared to the conventional multi-view planar imaging approach. We have extended V/Q SPECT processing to include coregistration, normalization and subtraction of the two scans. The unpredictable deposition of technegas activity in bronchi can introduce significant differences between otherwise normal V and Q scans and poses a challenge to both the coregistration and normalization needed before performing subtraction. QONSUB, a graphical-user-interface driven program originally written to assess epilepsy with brain SPECT (Badger and Barnden. Proc ANZSNM, 2008) has been adapted for assessment of V/Q lung SPECT. It includes rigid (+zoom) coregistration of the whole images or automatically determined sub images that contain the entire lungs. Count normalization was performed with either the mean or median counts. Extreme hot spots in ventilation images were observed to adversely affect the co-registration. We show that truncation to an upper threshold before co-registration corrects this. Similarly, normalization using a mean was seriously affected by such ventilation hotspots. This was circumvented by using the median instead. The program offers display of the ventilation, perfusion and difference images in 3 linked panels with mouse-driven roam through their transaxial, sagittal and coronal sections, and mouse-driven scaling. Dragging the cursor horizontally across a sagittal image causes the corresponding coronal sections to change in all 4 panels, and so on. The multi-panel 3D display was well accepted by physicians and the program's clinical usefulness is under evaluation.

  2. Optimization of dual-energy subtraction chest radiography by use of a direct-conversion flat-panel detector system.

    Science.gov (United States)

    Fukao, Mari; Kawamoto, Kiyosumi; Matsuzawa, Hiroaki; Honda, Osamu; Iwaki, Takeshi; Doi, Tsukasa

    2015-01-01

    We aimed to optimize the exposure conditions in the acquisition of soft-tissue images using dual-energy subtraction chest radiography with a direct-conversion flat-panel detector system. Two separate chest images were acquired at high- and low-energy exposures with standard or thick chest phantoms. The high-energy exposure was fixed at 120 kVp with the use of an auto-exposure control technique. For the low-energy exposure, the tube voltages and entrance surface doses ranged 40-80 kVp and 20-100 % of the dose required for high-energy exposure, respectively. Further, a repetitive processing algorithm was used for reduction of the image noise generated by the subtraction process. Seven radiology technicians ranked soft-tissue images, and these results were analyzed using the normalized-rank method. Images acquired at 60 kVp were of acceptable quality regardless of the entrance surface dose and phantom size. Using a repetitive processing algorithm, the minimum acceptable doses were reduced from 75 to 40 % for the standard phantom and to 50 % for the thick phantom. We determined that the optimum low-energy exposure was 60 kVp at 50 % of the dose required for the high-energy exposure. This allowed the simultaneous acquisition of standard radiographs and soft-tissue images at 1.5 times the dose required for a standard radiograph, which is significantly lower than the values reported previously.

  3. A subtraction scheme for computing QCD jet cross sections at NNLO. Integrating the iterated singly-unresolved subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, Paolo [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Zoltan [Debrecen Univ. (Hungary); Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research

    2010-11-15

    We perform the integration of all iterated singly-unresolved subtraction terms over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent-expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurentexpansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets. (orig.)

  4. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the iterated singly-unresolved subtraction terms

    Science.gov (United States)

    Bolzoni, Paolo; Somogyi, Gábor; Trócsányi, Zoltán

    2011-01-01

    We perform the integration of all iterated singly-unresolved subtraction terms, as defined in ref. [1], over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurent-expansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets.

  5. Mental Computation or Standard Algorithm? Children's Strategy Choices on Multi-Digit Subtractions

    Science.gov (United States)

    Torbeyns, Joke; Verschaffel, Lieven

    2016-01-01

    This study analyzed children's use of mental computation strategies and the standard algorithm on multi-digit subtractions. Fifty-eight Flemish 4th graders of varying mathematical achievement level were individually offered subtractions that either stimulated the use of mental computation strategies or the standard algorithm in one choice and two…

  6. The Use of Procedural Knowledge in Simple Addition and Subtraction Problems

    Science.gov (United States)

    Fayol, Michel; Thevenot, Catherine

    2012-01-01

    In a first experiment, adults were asked to solve one-digit additions, subtractions and multiplications. When the sign appeared 150 ms before the operands, addition and subtraction were solved faster than when the sign and the operands appeared simultaneously on screen. This priming effect was not observed for multiplication problems. A second…

  7. Subtraction with hadronic initial states at NLO: an NNLO-compatible scheme

    Science.gov (United States)

    Somogyi, Gábor

    2009-05-01

    We present an NNLO-compatible subtraction scheme for computing QCD jet cross sections of hadron-initiated processes at NLO accuracy. The scheme is constructed specifically with those complications in mind, that emerge when extending the subtraction algorithm to next-to-next-to-leading order. It is therefore possible to embed the present scheme in a full NNLO computation without any modifications.

  8. Subtraction with hadronic initial states at NLO: an NNLO-compatible scheme

    International Nuclear Information System (INIS)

    Somogyi, Gabor

    2009-01-01

    We present an NNLO-compatible subtraction scheme for computing QCD jet cross sections of hadron-initiated processes at NLO accuracy. The scheme is constructed specifically with those complications in mind, that emerge when extending the subtraction algorithm to next-to-next-to-leading order. It is therefore possible to embed the present scheme in a full NNLO computation without any modifications.

  9. SU-D-17A-02: Four-Dimensional CBCT Using Conventional CBCT Dataset and Iterative Subtraction Algorithm of a Lung Patient

    International Nuclear Information System (INIS)

    Hu, E; Lasio, G; Yi, B

    2014-01-01

    Purpose: The Iterative Subtraction Algorithm (ISA) method generates retrospectively a pre-selected motion phase cone-beam CT image from the full motion cone-beam CT acquired at standard rotation speed. This work evaluates ISA method with real lung patient data. Methods: The goal of the ISA algorithm is to extract motion and no- motion components form the full reconstruction CBCT. The workflow consists of subtracting from the full CBCT all of the undesired motion phases and obtain a motion de-blurred single-phase CBCT image, followed by iteration of this subtraction process. ISA is realized as follows: 1) The projections are sorted to various phases, and from all phases, a full reconstruction is performed to generate an image CTM. 2) Generate forward projections of CTM at the desired phase projection angles, the subtraction of projection and the forward projection will reconstruct a CTSub1, which diminishes the desired phase component. 3) By adding back the CTSub1 to CTm, no motion CBCT, CTS1, can be computed. 4) CTS1 still contains residual motion component. 5) This residual motion component can be further reduced by iteration.The ISA 4DCBCT technique was implemented using Varian Trilogy accelerator OBI system. To evaluate the method, a lung patient CBCT dataset was used. The reconstruction algorithm is FDK. Results: The single phase CBCT reconstruction generated via ISA successfully isolates the desired motion phase from the full motion CBCT, effectively reducing motion blur. It also shows improved image quality, with reduced streak artifacts with respect to the reconstructions from unprocessed phase-sorted projections only. Conclusion: A CBCT motion de-blurring algorithm, ISA, has been developed and evaluated with lung patient data. The algorithm allows improved visualization of a single phase motion extracted from a standard CBCT dataset. This study has been supported by National Institute of Health through R01CA133539

  10. Evaluation of the cardiovascular system by digital subtraction angiography in 246 patients

    Energy Technology Data Exchange (ETDEWEB)

    Higuma, Kikuhiko; Ohta, Takashi; Hiroto, Seiji

    1987-07-01

    Usefulness of intravenous digital subtraction angiography (DSA) was examined in 246 patients with cardiovascular disorders. This examination was done by centrally intravenous DSA (CIVDSA) in all patients to reduce the risks and discomforts by peripheral intravenous DSA. 1) CIVDSA could be done safely in patients aged 18 to 81 years. 2) The good diagnostic quality by CIVDSA was obtained in 81.3% of patients. These images were classified into 7 groups according to the cardiovascular system, that is, the jugular arteries, the upper extremity arteries, the thoracic aorta, the left ventricle, the abnominal aorta, the renal arteries, and the lower extremity arteries, whose rate of good diagnostic quality were 100%, 70%, 67.7%, 79.5%, 84.8%, 87%, and 71.4% respectively. 3) The poor diagnostic quality was obtained in 18.7%. 4) The severe complications were not found in any case during this examination. Our results indicate that DSA is the safe, simple and useful method to obtain the diagnostic quality image of the cardiovascular system, especially, of the occulsive arterial disease, the aortic aneurisma, the renovascular stenosis and the cardiac function of postmyocardial infarction, even in aged patients.

  11. Evaluation of the cardiovascular system by digital subtraction angiography in 246 patients

    International Nuclear Information System (INIS)

    Higuma, Kikuhiko; Ohta, Takashi; Hiroto, Seiji

    1987-01-01

    Usefulness of intravenous digital subtraction angiography (DSA) was examined in 246 patients with cardiovascular disorders. This examination was done by centrally intravenous DSA (CIVDSA) in all patients to reduce the risks and discomforts by peripheral intravenous DSA. 1) CIVDSA could be done safely in patients aged 18 to 81 years. 2) The good diagnostic quality by CIVDSA was obtained in 81.3 % of patients. These images were classified into 7 groups according to the cardiovascular system, that is, the jugular arteries, the upper extremity arteries, the thoracic aorta, the left ventricle, the abnominal aorta, the renal arteries, and the lower extremity arteries, whose rate of good diagnostic quality were 100 %, 70 %, 67.7 %, 79.5 %, 84.8 %, 87 %, and 71.4 % respectively. 3) The poor diagnostic quality was obtained in 18.7 %. 4) The severe complications were not found in any case during this examination. Our results indicate that DSA is the safe, simple and useful method to obtain the diagnostic quality image of the cardiovascular system, especially, of the occulsive arterial disease, the aortic aneurisma, the renovascular stenosis and the cardiac function of postmyocardial infarction, even in aged patients. (author)

  12. A posteriori registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment.

    Science.gov (United States)

    Kreich, Eliane Maria; Chibinski, Ana Cláudia; Coelho, Ulisses; Wambier, Letícia Stadler; Zedebski, Rosário de Arruda Moura; de Moraes, Mari Eli Leonelli; de Moraes, Luiz Cesar

    2016-03-01

    This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the posttreatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. The mean EARR observed was 15.44±12.1 pixels (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment.

  13. A posterior registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kreich, Eliane Maria; Chibinski, Ana Claudia; Coelho, Ulisses; Wambier, Leticia Stadler; Zedebski, Rosaio De Arruda Moura [School of Dentistry, Ponta Grossa State University, Ponta Grossa, Parana (Brazil); De Moraes, Mari Eli Leonelli; De Moraes, Luiz Cesar [Dept. of Dental Radiology, School of Dentistry, State University of Sao Paulo, Sao Jose dos Campos, Sao Paulo (Brazil)

    2016-03-15

    This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the posttreatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. The mean EARR observed was 15.44±12.1 pixels (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment.

  14. A posterior registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment

    International Nuclear Information System (INIS)

    Kreich, Eliane Maria; Chibinski, Ana Claudia; Coelho, Ulisses; Wambier, Leticia Stadler; Zedebski, Rosaio De Arruda Moura; De Moraes, Mari Eli Leonelli; De Moraes, Luiz Cesar

    2016-01-01

    This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the posttreatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. The mean EARR observed was 15.44±12.1 pixels (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment

  15. Influence of homeopathic treatment with comfrey on bone density around titanium implants: a digital subtraction radiography study in rats.

    Science.gov (United States)

    Sakakura, Celso Eduardo; Neto, Rubens Spin; Bellucci, Marina; Wenzel, Ann; Scaf, Gulnara; Marcantonio, Elcio

    2008-06-01

    The objective of this study was to evaluate the influence of homeopathic treatment with comfrey (Shymphytum officinalis 6CH) on radiographic bone density and area around titanium implants. Forty-eight rats were divided into two groups of 24 animals each: a control group (C) and a test group (SO). Each animal received one titanium micro-implant placed in the tibia. The animals in Group SO were subjected to 10 drops of comfrey 6CH per day mixed into their drinking water until the day of sacrifice. Eight animals of each group were sacrificed at 7, 14 and 28 days post-surgery, respectively. Standardized digital radiographs were obtained on the day of implant installation (baseline images) and on the day of sacrifice (final images). Digital subtraction of the two corresponding images was performed to evaluate changes in bone density and the area related to change around the implant between baseline and final images. Subtraction images demonstrated that a significant difference existed in mean shade of gray at 14 days post-surgery between Group SO (mean 175.3+/-14.4) and Group C (mean 146.2+/-5.2). Regarding the area in pixels corresponding to the bone gain in Group SO, the differences observed between the sacrifice periods and groups were only significant at 7 days sacrifice between Group SO (mean 171.2+/-21.9) and Group C (mean 64.5+/-60.4). Within the limits of this study, comfrey administration promotes an increase in radiographic bone density around titanium implants in the initial period of bone healing.

  16. Identification of formaldehyde-responsive genes by suppression subtractive hybridization

    International Nuclear Information System (INIS)

    Lee, Min-Ho; Kim, Young-Ae; Na, Tae-Young; Kim, Sung-Hye; Shin, Young Kee; Lee, Byung-Hoon; Shin, Ho-Sang; Lee, Mi-Ock

    2008-01-01

    Formaldehyde is frequently used in indoor household and occupational environments. Inhalation of formaldehyde invokes an inflammatory response, including a variety of allergic signs and symptoms. Therefore, formaldehyde has been considered as the most prevalent cause of sick building syndrome, which has become a major social problem, especially in developing urban areas. Further formaldehyde is classified as a genotoxicant in the respiratory tract of rats and humans. To better understand the molecular mechanisms involved in formaldehyde intoxication, we sought differentially regulated genes by formaldehyde exposure to Hs 680.Tr human trachea cells, using polymerase chain reaction (PCR)-based suppression subtractive hybridization. We identified 27 different formaldehyde-inducible genes, including those coding for the major histocompatibility complex, class IA, calcyclin, glutathione S-transferase pi, mouse double minute 2 (MDM2), platelet-derived growth factor receptor alpha, and which are known to be associated with cell proliferation and differentiation, immunity and inflammation, and detoxification. Induction of these genes by formaldehyde treatment was confirmed by reverse transcription PCR and western blot analysis. Further, the expression of calcyclin, glutathione S-transferase pi, PDGFRA and MDM2 were significantly induced in the tracheal epithelium of Sprague Dawley rats after formaldehyde inhalation. Our results suggest that the elevated levels of these genes may be associated with the formaldehyde-induced toxicity, and that they deserve evaluation as potential biomarkers for formaldehyde intoxication

  17. Radiation doses to patients from digital subtraction angiography

    International Nuclear Information System (INIS)

    Goni, H.; Tsalafoutas, I. A.; Tzortzis, G.; Pappas, P.; Bouzas, N.; Loulakas, J.; Georgiou, A.; Georgiou, E.; Yakoumakis, E. N.

    2005-01-01

    This investigation determined patient doses during digital subtraction angiography (DSA). Fluoroscopy time, dose-area product (DAP) and entrance surface air kerma (ESAK) were analysed from 263 DSA examinations, classified into seven categories: (1) abdominal aorta, iliac, femoral, popliteal and leg arteries; (2) abdominal aorta and super-selective DSA of renal arteries; (3) combination of (1) and (2); (4) super-selective DSA of common carotid and vertebral arteries, intracranial branches in face and profile projections; (5) super-selective DSA of hepatic, splenic, superior and inferior mesenteric arteries; (6) combination of (1) and (4); and (7) celiac trunk and branches. Median DAP values were 67.7, 92.9, 76.6, 53.6, 105.7, 76.1 and 2.6 Gy cm 2 , respectively. With the exception of one examination, ESAK values were below 2 Gy: the limit for erythema. Compared with published data, DAP values were within the range reported for (1) and (4), slightly larger for (2) and (5), whereas no references were identified for the remaining three categories. (authors)

  18. Matching the quasiparton distribution in a momentum subtraction scheme

    Science.gov (United States)

    Stewart, Iain W.; Zhao, Yong

    2018-03-01

    The quasiparton distribution is a spatial correlation of quarks or gluons along the z direction in a moving nucleon which enables direct lattice calculations of parton distribution functions. It can be defined with a nonperturbative renormalization in a regularization independent momentum subtraction scheme (RI/MOM), which can then be perturbatively related to the collinear parton distribution in the MS ¯ scheme. Here we carry out a direct matching from the RI/MOM scheme for the quasi-PDF to the MS ¯ PDF, determining the non-singlet quark matching coefficient at next-to-leading order in perturbation theory. We find that the RI/MOM matching coefficient is insensitive to the ultraviolet region of convolution integral, exhibits improved perturbative convergence when converting between the quasi-PDF and PDF, and is consistent with a quasi-PDF that vanishes in the unphysical region as the proton momentum Pz→∞ , unlike other schemes. This direct approach therefore has the potential to improve the accuracy for converting quasidistribution lattice calculations to collinear distributions.

  19. Experience with digital subtraction angiography of cervicocranial region

    International Nuclear Information System (INIS)

    Bohutova, J.; Neuwirth, J.; Kuncova, S.; Lerlova, L.

    1988-01-01

    Digital subtraction angiography (DSA) of the head was performed in 100 patients for mostly neurological indications, less frequently pathological processes in the region of the external carotid artery. The intravenous or intraarterial route was selected according to the condition and age of the patient and clinical diagnosis. In 55% of cases the contrast medium was administered into the ascending aorta, in 13% selectively into the carotid or vertebral arteries. The examination was performed intravenously in 32%, most frequently via inferior vena cava (26%). The visualization of the whole area of the carotid and vertebral arteries from the ramification of the aortal arc up to the periphery requires to make at least 4 to 5 administrations of contrast medium, since simultaneous representation of lateral and AP projection for DSA has not been so far possible and the screen size is small. In intravenous DSA the amount of contrast medium increases up to 200 ml. Instillation into the ascending artery is therefore preferred and half of the amount is thus sufficient. DSA has proved of advantage in the examination of patients with arteriosclerosis, angiomas and arteriovenous malformations, vascularized and avascular expansive processes in intracranial and extracranial localizations. Quality angiograms were obtained in 84%, those still suitable for evaluation in 14% and useless in 2% of cases. (author). 14 figs., 1 tab., 16 refs

  20. Role of digital tomosynthesis and dual energy subtraction digital radiography in detecting pulmonary nodules

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sarvana G. [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Garg, Mandeep Kumar, E-mail: gargmandeep01@gmail.com [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Khandelwal, Niranjan; Gupta, Pankaj [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Gupta, Dheeraj; Aggarwal, Ashutosh Nath [Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Bansal, Subash Chand [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India)

    2015-07-15

    Highlights: • Accuracy of digital tomosynthesis for nodule detection is substantially higher. • Improvement in diagnostic accuracy is most pronounced for nodules <10 mm. • There is five times increase in radiation dose compared to DR. - Abstract: Objective: Digital tomosynthesis (DT) and dual-energy subtraction digital radiography (DES-DR) are known to perform better than conventional radiography in the detection of pulmonary nodules. Yet the comparative diagnostic performances of DT, DES-DR and digital radiography (DR) is not known. The present study compares the diagnostic performances of DT, DES-DR and DR in detecting pulmonary nodules. Subjects and methods: The institutional Review Board approved the study and informed written consent was obtained. Fifty-five patients (30 with pulmonary nodules, 25 with non-nodular focal chest pathology) were included in the study. DT and DES-DR were performed within14 days of MDCT. Composite images acquired at high kVp as part of DES-DR were used as DR images. Images were analyzed for presence of nodules and calcification in nodules. Interpretations were assigned confidence levels from 1 to 5 according to Five-Point rating scale. Areas under the receiver operating characteristic curves were compared using Z test. Results: A total of 110 (88 non-calcified, 22 calcified) nodules were identified on MDCT. For detection of nodules, DR showed cumulative sensitivity and specificity of 25.45% and 67.97%, respectively. DT showed a cumulative sensitivity and specificity of 60.9% and 85.07%, respectively. The performance was significantly better than DR (p < 0.003). DES-DR showed sensitivity and specificity of 27.75% and 82.64%, not statistically different from those of DR (p—0.92). In detection of calcification, there was no statistically significant difference between DT, DES-DR and DR. Conclusions: DT performs significantly better than DES-DR and DR at the cost of moderate increase in radiation dose.

  1. Digital subtraction arthrography in preoperative evaluation of painful total hip arthroplasty

    International Nuclear Information System (INIS)

    Ginai, A.Z.; Biezen, F.C. van; Kint, P.A.M.; Oei, H.Y.; Hop, W.C.J.

    1996-01-01

    Digital subtraction arthrograms, scintigrams and plain radiographs of 70 consecutive patients who underwent revision hip arthroplasty were scored individually and in masked fashion for the presence or absence of features indicating loosening of femoral and/or acetabular components. The operative findings acted as the gold standard. Digital subtraction arthrography was best for predicting a loose acetabular component, while no significant additional predictive value was found for plain radiographs and scintigraphy. Digital subtraction arthrography was also the most important modality for predicting a loose femoral component, while the plain radiograph was of significant additional value and scintigraphy was of no additional value on multivariate analysis. (orig./MG)

  2. A comparison between magnetic resonance angiography at 3 teslas (time-of-flight and contrast-enhanced and flat-panel digital subtraction angiography in the assessment of embolized brain aneurysms

    Directory of Open Access Journals (Sweden)

    Guilherme S. Nakiri

    2011-01-01

    Full Text Available PURPOSE: To compare the time-of-flight and contrast-enhanced- magnetic resonance angiography techniques in a 3 Tesla magnetic resonance unit with digital subtraction angiography with the latest flat-panel technology and 3D reconstruction in the evaluation of embolized cerebral aneurysms. INTRODUCTION: Many embolized aneurysms are subject to a recurrence of intra-aneurismal filling. Traditionally, imaging surveillance of coiled aneurysms has consisted of repeated digital subtraction angiography. However, this method has a small but significant risk of neurological complications, and many authors have advocated the use of noninvasive imaging methods for the surveillance of embolized aneurysms. METHODS: Forty-three aneurysms in 30 patients were studied consecutively between November 2009 and May 2010. Two interventional neuroradiologists rated the time-of-flight-magnetic resonance angiography, the contrast-enhanced-magnetic resonance angiography, and finally the digital subtraction angiography, first independently and then in consensus. The status of aneurysm occlusion was assessed according to the Raymond scale, which indicates the level of recanalization according to degrees: Class 1: excluded aneurysm; Class 2: persistence of a residual neck; Class 3: persistence of a residual aneurysm. The agreement among the analyses was assessed by applying the Kappa statistic. RESULTS: Inter-observer agreement was excellent for both methods (K = 0.93; 95 % CI: 0.84-1. Inter-technical agreement was almost perfect between time-of-flight-magnetic resonance angiography and digital subtraction angiography (K = 0.98; 95 % CI: 0.93-1 and between time-of-flight-magnetic resonance angiography and contrast-enhanced-magnetic resonance angiography (K = 0.98; 95% CI: 0.93-1. Disagreement occurred in only one case (2.3%, which was classified as Class I by time-of-flight-magnetic resonance angiography and Class II by digital subtraction angiography. The agreement between

  3. Feasibility study of 2D thick-slice MR digital subtraction angiography

    International Nuclear Information System (INIS)

    Ishimori, Yoshiyuki; Takeuchi, Miho; Higashimura, Kyouji; Komuro, Hiroyuki

    2000-01-01

    Conditions required to perform contrast MR digital subtraction angiography using a two-dimensional thick-slice high-speed gradient echo were investigated. The conditions in the phantom experiment included: slice profile, flip angle, imaging matrix, fat suppression, duration of IR pulse and frequency selectivity, flip angle of IR pulse and inversion time. Based on the results of the experiment, 2D thick-slice MRDSA was performed in volunteers. Under TR/TE=5.3-9/1.3-1.8 ms conditions, the requirements were a slice thick enough to include the target region, a flip angle of 10 degrees, and a phase matrix of 96 or more. Fat suppression was required for adipose-tissue-rich regions, such as the abdomen. The optimal conditions for applying the IR preparation pulse of the IR prepped fast gradient recalled echo as spectrally selective inversion recovery appeared to be: duration of IR pulse =20 ms, flip angle =100 degrees, and inversion time =40 ms. The authors concluded that it was feasible to perform 2D thick-slice MRDSA with time resolution within 1 second. (K.H.)

  4. Computed tomography versus digital subtraction angiography for the diagnosis of obscure gastrointestinal bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Wildgruber, Moritz, E-mail: moritzwildgruber@ukmuenster.de [Institut für Röntgendiagnostik, Universitätsklinikum Regensburg, D-93053 Regensburg (Germany); Institut für klinische Radiologie, Universitätsklinikum Münster, D-48149 Münster (Germany); Wrede, Christian E. [Notfallzentrum, Helios Klinikum Berlin-Buch, D-13125 Berlin (Germany); Zorger, Niels [Institut für Radiologie, Neuroradiologie und Nuklearmedizin, Krankenhaus Barmherzige Brüder, D-93049 Regensburg (Germany); Müller-Wille, René; Hamer, Okka W. [Institut für Röntgendiagnostik, Universitätsklinikum Regensburg, D-93053 Regensburg (Germany); Zeman, Florian [Zentrum für Klinische Studien, Universitätsklinikum Regensburg, D-93053 Regensburg (Germany); Stroszczynski, Christian; Heiss, Peter [Institut für Röntgendiagnostik, Universitätsklinikum Regensburg, D-93053 Regensburg (Germany)

    2017-03-15

    Purpose: The diagnostic yield of computed tomography angiography (CTA) compared to digital subtraction angiography (DSA) for major obscure gastrointestinal bleeding (OGIB) is not known. Aim of the study was to prospectively evaluate the diagnostic yield of CTA versus DSA for the diagnosis of major OGIB. Material and methods: The institutional review board approved the study and informed consent was obtained from each patient. Patients with major OGIB were prospectively enrolled to undergo both CTA and DSA. Two blinded radiologists each reviewed the CTA and DSA images retrospectively and independently. Contrast material extravasation into the gastrointestinal lumen was considered diagnostic for active bleeding. Primary end point of the study was the diagnostic yield, defined as the frequency a technique identified an active bleeding or a potential bleeding lesion. The diagnostic yield of CTA and DSA were compared by McNemar's test. Results: 24 consecutive patients (11 men; median age 64 years) were included. CTA and DSA identified an active bleeding or a potential bleeding lesion in 92% (22 of 24 patients; 95% CI 72%–99%) and 29% (7 of 24 patients; 95% CI 12%–49%) of patients, respectively (p < 0.001). CTA and DSA identified an active bleeding in 42% (10 of 24; 95% CI 22%–63%) and 21% (5 of 24; 95% CI 7%–42%) of patients, respectively (p = 0.06). Conclusion: Due to the lower invasiveness and higher diagnostic yield CTA should be favored over DSA for the diagnosis of major OGIB.

  5. Computed tomography versus digital subtraction angiography for the diagnosis of obscure gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Wildgruber, Moritz; Wrede, Christian E.; Zorger, Niels; Müller-Wille, René; Hamer, Okka W.; Zeman, Florian; Stroszczynski, Christian; Heiss, Peter

    2017-01-01

    Purpose: The diagnostic yield of computed tomography angiography (CTA) compared to digital subtraction angiography (DSA) for major obscure gastrointestinal bleeding (OGIB) is not known. Aim of the study was to prospectively evaluate the diagnostic yield of CTA versus DSA for the diagnosis of major OGIB. Material and methods: The institutional review board approved the study and informed consent was obtained from each patient. Patients with major OGIB were prospectively enrolled to undergo both CTA and DSA. Two blinded radiologists each reviewed the CTA and DSA images retrospectively and independently. Contrast material extravasation into the gastrointestinal lumen was considered diagnostic for active bleeding. Primary end point of the study was the diagnostic yield, defined as the frequency a technique identified an active bleeding or a potential bleeding lesion. The diagnostic yield of CTA and DSA were compared by McNemar's test. Results: 24 consecutive patients (11 men; median age 64 years) were included. CTA and DSA identified an active bleeding or a potential bleeding lesion in 92% (22 of 24 patients; 95% CI 72%–99%) and 29% (7 of 24 patients; 95% CI 12%–49%) of patients, respectively (p < 0.001). CTA and DSA identified an active bleeding in 42% (10 of 24; 95% CI 22%–63%) and 21% (5 of 24; 95% CI 7%–42%) of patients, respectively (p = 0.06). Conclusion: Due to the lower invasiveness and higher diagnostic yield CTA should be favored over DSA for the diagnosis of major OGIB.

  6. Visualization of μ1 opiate receptors in rat brain by using a computerized autoradiographic subtraction technique

    International Nuclear Information System (INIS)

    Goodman, R.R.; Pasternak, G.W.

    1985-01-01

    The authors have developed a quantitative computerized subtraction technique to demonstrate in rat brain the regional distribution of μ 1 sites, a common very-high-affinity binding site for both morphine and the enkephalins. Low concentrations of [D-Ala 2 , D-Leu 5 ]enkephalin selectively inhibit the μ 1 binding of [ 3 H]dihydromorphine, leaving μ 2 -sites, while low morphine concentrations eliminate the μ 1 binding of [ 3 H][D-Ala 2 , D-Leu 5 ]enkephalin, leaving sigma sites. Thus, quantitative differences between images of sections incubated in the presence and absence of these low concentrations of unlabeled opioid represent μ 1 binding sites. The regional distributions of μ 1 sites labeled with [ 3 H]dihydromorphine were quite similar to those determined by using [ 3 H][D-Ala 2 , D-Leu 5 ]enkephalin. High levels of μ 1 binding were observed in the periaqueductal gray, medial thalamus, and median raphe, consistent with the previously described role of μ 1 sites in analgesia. Other regions with high levels of μ 1 binding include the nucleus accumbens, the clusters and subcallosal streak of the striatum, hypothalamus, medial habenula, and the medial septum/diagonal band region. The proportion of total specific binding corresponding to μ 1 sites varied among the regions, ranging from 14% to 75% for [ 3 H][D-Ala 2 , D-Leu 5 ]enkephalin and 20% to 52% for [ 3 H]dihydromorphine

  7. 3D printing of intracranial aneurysm based on intracranial digital subtraction angiography and its clinical application.

    Science.gov (United States)

    Wang, Jian-Li; Yuan, Zi-Gang; Qian, Guo-Liang; Bao, Wu-Qiao; Jin, Guo-Liang

    2018-06-01

    The study aimed to develop simulation models including intracranial aneurysmal and parent vessel geometries, as well as vascular branches, through 3D printing technology. The simulation models focused on the benefits of aneurysmal treatments and clinical education. This prospective study included 13 consecutive patients who suffered from intracranial aneurysms confirmed by digital subtraction angiography (DSA) in the Neurosurgery Department of Shaoxing People's Hospital. The original 3D-DSA image data were extracted through the picture archiving and communication system and imported into Mimics. After reconstructing and transforming to Binary STL format, the simulation models of the hollow vascular tree were printed using 3D devices. The intracranial aneurysm 3D printing simulation model was developed based on DSA to assist neurosurgeons in aneurysmal treatments and residency training. Seven neurosurgical residents and 15 standardization training residents received their simulation model training and gave high assessments for the educational course with the follow-up qualitative questionnaire. 3D printed simulation models based on DSA can perfectly reveal target aneurysms and help neurosurgeons select therapeutic strategies precisely. As an educational tool, the 3D aneurysm vascular simulation model is useful for training residents.

  8. Experience with intravenous digital subtraction angiography following shunting in 4 cases of congenital heart diseases

    Energy Technology Data Exchange (ETDEWEB)

    Higashidate, Masafumi; Konno, Susumu; Sumitomo, Naokata; Ito, Sango; Kobayashi, Hiroshi

    1985-01-01

    Intravenous digital subtraction angiography (IV-DSA) was performed in two patients with Fallot's tetralogy who underwent Blalock-Taussing operation, a patient with coarctation of the aortic arch who underwent extra-anastomic bypass between the ascending aorta and the descending aorta, and a patient with stenosis of the tricuspid valve who underwent Fontan type operation (anastomosis between the right atrium and the pulmonary artery). The conventional cardiac angiography was also performed for the comparison with IV-DSA in all patients. IV-DSA revealed the thickness of the subclavian artery anastomosed by Blaloch-Taussing operation, but failed to determine the accurate thickness of the pulmonary artery required for PA-index for radical surgery in cases of Fallot's tetralogy. Bypass from the ascending aorta to the descending aorta was well visualized by IV-DSA because the heart did not overlap on the image. In cases of Fontan type operation, IV-DSA permitted the visualization of blood flow from the right atrium to the pulmonary artery and the shape of the pulmonary artery. It is concluded that IV-DSA is a less invasive, simple technique to evaluate patients' condition following shunting for congenital heart diseases, as compared to the conventional method. (Namekawa, K.).

  9. Detection and characterization of intracranial aneurysms: magnetic resonance angiography versus digital subtraction angiography

    International Nuclear Information System (INIS)

    Shahzad, R.; Younas, F.

    2011-01-01

    Objective: To compare magnetic resonance angiography (MRA) with Intra-arterial digital subtraction angiography (IA-DSA) in detection and characterization of intracranial aneurysms. Study Design: Comparative cross-sectional study. Place and Duration of Study: Department of Diagnostic Imaging, Lahore General Hospital, Lahore, from January to June 2007. Methodology: Thirty patients presented with aneurysmal subarachnoid haemorrhage (SAH) and focal neurological signs were selected by convenience sampling. Three dimensional time of flight (3D TOF) MRA using maximum intensity projection (MIP) was performed on all patients along with DSA. Results of 3D TOF MRA were compared with those of IA-DSA taking IA-DSA as Gold standard. Results: Out of 30 patients 14 (46.7%) were males and 16 (53.3%) were females with mean age of 41+-14.1 years. MRA detected 29 out of 30 aneurysmal lesions with sensitivity of 96.7%. Regarding characterization of aneurysms results of MRA were comparable to those of IA-DSA. Conclusion: 3D TOF MRA technique showed a high sensitivity in this study. This technique can be used as a non-invasive screening test for intracranial aneurysms and as a suitable alternative primary examination to IA-DSA prior to aneurysmal surgery. (author)

  10. Headache-like Subarachnoid Hemorrhage After Digital Subtraction Angiography: A Case Report

    Directory of Open Access Journals (Sweden)

    Fettah Eren

    2018-03-01

    Full Text Available Subarachnoid hemorrhage (SAH is a clinical condition with acute-onset, sudden, and severe headache. In addition to headache, severe nausea, vomiting, dizziness, confusion, agitation, focal neurologic deficits, and hypertension can be detected. Findings of meningeal irritation may accompany to these clinical features, 6-24 hours after the hemorrhage. Digital subtraction angiography (DSA is used for surgical or endovascular treatment planning in order to identify vascular abnormalities, in addition to other imaging studies. After DSA, the frequency of all neurologic complications is between 0.2% and 4.5%. Headache may occur after DSA in an average 50% of patients. This rate is especially higher in female patients. Headache types are usually classified as migraine, tension or postoperative atypical headaches The incidence of severe headache after DSA is low. Vascular wall rupture should be considered first in severe headache after the procedure. It should also be kept in mind that after all other secondary causes are excluded; SAH-like headaches after DSA can be detected

  11. Intravenous vs. left ventricular injection of ionic contrast material: hemodynamic implications for digital subtraction angiography

    International Nuclear Information System (INIS)

    Mancini, G.B.; Ostrander, D.R.; Slutsky, R.A.; Shabetai, R.; Higgins, C.B.

    1983-01-01

    Because of the increased use of intravenous injection of contrast material for the evaluation of cardiac structure and function by digital subtraction techniques, a study was done to assess the hemodynamic effects of contrast material when used in this fashion in man. In 10 patients, with each serving as his own control, the effects of intravenous and intraventricular injections of sodium meglumine diatrizoate (Renografin 76) in the same dose were compared. There was no difference between these two methods with respect to changes in pulmonary wedge pressures, systemic pressures, and pulmonary vascular resistance. The elevation of mean pulmonary artery and right atrial pressure was greater after the intraventricular injection (p <0.05). The elevated cardiac output and systemic vascular resistance returned to control values somewhat more quickly after the intravenous injection (p<0.001 and p<0.05, respectively); and the increase in cardiac output was greater after the intravenous injection at 1 min (p<0.05), but less than after the intraventricular injection at 2 min (p<0.05). Despite the detection of these statistically significant differences, the magnitude and timing of these differences are too small to justify the notion that imaging by intravenous injections of standard ionic contrast media provides any substantial hemodynamic benefits or decreased risk to the patient

  12. Experience with intravenous digital subtraction angiography following shunting in 4 cases of congenital heart diseases

    International Nuclear Information System (INIS)

    Higashidate, Masafumi; Konno, Susumu; Sumitomo, Naokata; Ito, Sango; Kobayashi, Hiroshi

    1985-01-01

    Intravenous digital subtraction angiography (IV-DSA) was performed in two patients with Fallot's tetralogy who underwent Blalock-Taussing operation, a patient with coarctation of the aortic arch who underwent extra-anastomic bypass between the ascending aorta and the descending aorta, and a patient with stenosis of the tricuspid valve who underwent Fontan type operation (anastomosis between the right atrium and the pulmonary artery). The conventional cardiac angiography was also performed for the comparison with IV-DSA in all patients. IV-DSA revealed the thickness of the subclavian artery anastomosed by Blaloch-Taussing operation, but failed to determine the accurate thickness of the pulmonary artery required for PA-index for radical surgery in cases of Fallot's tetralogy. Bypass from the ascending aorta to the descending aorta was well visualized by IV-DSA because the heart did not overlap on the image. In cases of Fontan type operation, IV-DSA permitted the visualization of blood flow from the right atrium to the pulmonary artery and the shape of the pulmonary artery. It is concluded that IV-DSA is a less invasive, simple technique to evaluate patients' condition following shunting for congenital heart diseases, as compared to the conventional method. (Namekawa, K.)

  13. DIAGNOSTIC ACCURACY OF MAGNETIC RESONANCE ANGIOGRAPHY FOR UNRUPTURED CEREBRAL ANEURYSMS IN CORRELATION WITH DIGITAL SUBTRACTION ANGIOGRAPHY

    Directory of Open Access Journals (Sweden)

    Aleksandra Aracki-Trenkić

    2015-09-01

    Full Text Available Intracranial aneurysm is a focal, abnormal dilation of an artery of the brain. Magnetic resonance angiography (MRA is a non-invasive technique for vascular imaging and is thus widely used for screening for intracranial vascular lesions. The aim of the study was to show the diagnostic accuracy of 3D Time-of-Flight (3D TOF MRA in the detection of unruptured cerebral aneurysms with the use of digital subtraction angiography (DSA as the gold standard. A total of 2.612 consecutive patients underwent 3DTOF MRA. It showed unruptured aneurysms in 94 (3.6% patients. They included 68 women and 26 men ranging in age from 29 to 76 years (mean, 52.5 years. Twenty-six of them, 20 women and 6 men, underwent DSA. The Mann-Whitney U test was used for the correlation of size. Fisher’s test was used for the correlation of location. The statistical level of significance was set at p0.05 of aneurysms between TOF MRA and DSA. MRA is an accurate and non-invasive method for diagnosis of unruptured intracranial aneurysms. The results of study show the compatibility of MRA findings, the location and the size of an aneurysm in comparison with the “gold standard” – cerebral DSA.

  14. Experimental determination of the weighting factor for the energy window subtraction-based downscatter correction for I-123 in brain SPECT studies

    DEFF Research Database (Denmark)

    de Nijs, Robin; Holm, Søren; Thomsen, Gerda

    2010-01-01

    Correction for downscatter in I-123 SPECT can be performed by the subtraction of a secondary energy window from the main window, as in the triple-energy window method. This is potentially noise sensitive. For studies with limited amount of counts (e.g. dynamic studies), a broad subtraction window...... were investigated in this study. Energy windows with a width of 32 keV were centered at 159 keV and 200 keV. The weighting factor was measured both with an I-123 point source and in a dopamine transporter brain SPECT study in 10 human subjects (5 healthy subjects and 5 patients) by minimizing...... the background outside the head. Weighting factors ranged from 1.11 to 1.13 for the point source and from 1.16 to 1.18 for human subjects. Point source measurements revealed no position dependence. After correction, the measured specific binding ratio (image contrast) increased significantly for healthy subjects...

  15. Safety of Diagnostic Cerebral and Spinal Digital Subtraction Angiography in a Developing Country: A Single-Center Experience.

    Science.gov (United States)

    Bashir, Qasim; Ishfaq, Asim; Baig, Ammad Anwar

    2018-02-01

    Digital subtraction angiography (DSA) remains the gold standard imaging modality for cerebrovascular disorders. In contrast to developed countries, the safety of the procedure is not extensively reported from the developing countries. Herein, we present a retrospective analysis of the basic technique, indications, and outcomes in 286 patients undergoing diagnostic cerebral and spinal angiography in a developing country, Pakistan. A retrospective review of patient demographics, procedural technique and complication rates of 286 consecutive patients undergoing the diagnostic cerebral/spinal angiography procedure at one institution from May 2013 to December 2015 was performed. Neurological, systemic, or local complications occurring within and after 24 h of the procedure were recorded. Mean age reported for all patients was 49.7 years. Of all the 286 cases, 175 were male (61.2%) and the rest female (111, 38.8%). Cerebral DSA was performed in 279 cases (97.6%), with 7 cases of spinal DSA (2.4%). Subarachnoid hemorrhage was the most common indication for DSA accounting for 88 cases (30.8%), closely followed by stroke (26.6%) and arteriosclerotic vascular disease (23.1%). No intra- or post-procedural neurological complications of any severity were seen in any of the 286 cases. One case of asymptomatic aortic dissection was reported (0.3%) in the entire cohort of patient population. Diagnostic cerebral/spinal digital subtraction angiography was found to be safe in Pakistan, with complication rates at par with and comparable to those reported in the developed world.

  16. Femoral head vascularisation in Legg-Calve-Perthes disease: comparison of dynamic gadolinium-enhanced subtraction MRI with bone scintigraphy

    International Nuclear Information System (INIS)

    Lamer, Sylvie; Dorgeret, Sophie; Brillet, Pierre-Yves; Hassan, Max; Sebag, Guy H.; Khairouni, Abdeslam; Mazda, Keyvan; Bacheville, Eric; Pennecot, Georges F.; Bloch, Juliette

    2002-01-01

    Heading AbstractBackground. It has been reported that MRI using a dynamic gadolinium-enhanced subtraction technique can allow the early identification of ischaemia and the pattern of revascularisation in Legg-Calve-Perthes (LCP) disease with increased spatial and contrast resolution. Therefore, dynamic gadolinium-enhanced subtraction (DGS) MRI may be a possible non-ionising substitute for bone scintigraphy.Objective. The purpose of this prospective study was to compare DGS MRI and bone scintigraphy in the assessment of femoral head perfusion in LCP disease.Materials and methods. Twenty-six DGS MR images and bone scintigraphies of 25 hips in 23 children were obtained at different stages of LCP disease; three stage I, 12 stage II, six stage III and five stage IV (Waldenstroem classification). The extent of necrosis, epiphyseal revascularisation pathways (lateral pillar, medial pillar, and/or transphyseal perfusion) and metaphyseal changes were analysed.Results. Total agreement between both techniques was noted in the depiction of epiphyseal necrosis (kappa=1), and metaphyseal abnormalities (kappa=0.9). DGS MRI demonstrated better revascularisation in the lateral (kappa=0.62) and medial pillars (kappa=0.52). The presence of basal transphyseal reperfusion was more conspicuous with MRI.Conclusions. DGS MRI allows early detection of epiphyseal ischaemia and accurate analysis of the different revascularisation patterns. These changes are directly related to the prognosis of LCP disease and can aid therapeutic decision making. (orig.)

  17. Ultrasound contrast-agent improves imaging of lower limb occlusive disease

    DEFF Research Database (Denmark)

    Eiberg, J P; Hansen, M A; Jensen, F

    2003-01-01

    to evaluate if ultrasound contrast-agent infusion could improve duplex-ultrasound imaging of peripheral arterial disease (PAD) and increase the agreement with digital subtraction arteriography (DSA).......to evaluate if ultrasound contrast-agent infusion could improve duplex-ultrasound imaging of peripheral arterial disease (PAD) and increase the agreement with digital subtraction arteriography (DSA)....

  18. K-Edge Subtraction Angiography with Synchrotron X-Rays

    CERN Document Server

    Giacomini, J C

    1996-01-01

    The purpose of this project was to utilize dual energy, monochromatic X-rays produced from synchrotrons radiation in order to obtain noninvasive medical imaging. The application of synchrotrons radiation to medical imaging is based on the principle of iodine dichromography, first described by Bertil Jacobson of the Karolinska Institute in 1953. Medical imaging using synchrotrons radiation and K-edge dichromography was pioneered at Stanford University under the leadership of Dr. Ed Rubenstein, and the late Nobel Laureate in Physics, Dr. Robert Hofstadter. With progressive refinements in hardware, clinical-quality images were obtained of human coronary arteries utilizing peripheral injections of iodinated contrast agent. These images even now are far superior to those being presented by investigators using MRI as an imaging tool for coronary arteries. However, new supplies and instruments in the cardiac catheterization laboratory have served to transform coronary angiography into an outpatient procedure, with r...

  19. Lung nodule detection by microdose CT versus chest radiography (standard and dual-energy subtracted).

    Science.gov (United States)

    Ebner, Lukas; Bütikofer, Yanik; Ott, Daniel; Huber, Adrian; Landau, Julia; Roos, Justus E; Heverhagen, Johannes T; Christe, Andreas

    2015-04-01

    The purpose of this study was to investigate the feasibility of microdose CT using a comparable dose as for conventional chest radiographs in two planes including dual-energy subtraction for lung nodule assessment. We investigated 65 chest phantoms with 141 lung nodules, using an anthropomorphic chest phantom with artificial lung nodules. Microdose CT parameters were 80 kV and 6 mAs, with pitch of 2.2. Iterative reconstruction algorithms and an integrated circuit detector system (Stellar, Siemens Healthcare) were applied for maximum dose reduction. Maximum intensity projections (MIPs) were reconstructed. Chest radiographs were acquired in two projections with bone suppression. Four blinded radiologists interpreted the images in random order. A soft-tissue CT kernel (I30f) delivered better sensitivities in a pilot study than a hard kernel (I70f), with respective mean (SD) sensitivities of 91.1%±2.2% versus 85.6%±5.6% (p=0.041). Nodule size was measured accurately for all kernels. Mean clustered nodule sensitivity with chest radiography was 45.7%±8.1% (with bone suppression, 46.1%±8%; p=0.94); for microdose CT, nodule sensitivity was 83.6%±9% without MIP (with additional MIP, 92.5%±6%; pmicrodose CT for readers 1, 2, 3, and 4 were 84.3%, 90.7%, 68.6%, and 45.0%, respectively. Sensitivities with chest radiography for readers 1, 2, 3, and 4 were 42.9%, 58.6%, 36.4%, and 90.7%, respectively. In the per-phantom analysis, respective sensitivities of microdose CT versus chest radiography were 96.2% and 75% (pmicrodose CT, the applied dose was 0.1323 mSv. Microdose CT is better than the combination of chest radiography and dual-energy subtraction for the detection of solid nodules between 5 and 12 mm at a lower dose level of 0.13 mSv. Soft-tissue kernels allow better sensitivities. These preliminary results indicate that microdose CT has the potential to replace conventional chest radiography for lung nodule detection.

  20. A multiple regression analysis for accurate background subtraction in 99Tcm-DTPA renography

    International Nuclear Information System (INIS)

    Middleton, G.W.; Thomson, W.H.; Davies, I.H.; Morgan, A.

    1989-01-01

    A technique for accurate background subtraction in 99 Tc m -DTPA renography is described. The technique is based on a multiple regression analysis of the renal curves and separate heart and soft tissue curves which together represent background activity. It is compared, in over 100 renograms, with a previously described linear regression technique. Results show that the method provides accurate background subtraction, even in very poorly functioning kidneys, thus enabling relative renal filtration and excretion to be accurately estimated. (author)

  1. Comparison of two interpolative background subtraction methods using phantom and clinical data

    International Nuclear Information System (INIS)

    Houston, A.S.; Sampson, W.F.D.

    1989-01-01

    Two interpolative background subtraction methods used in scintigraphy are tested using both phantom and clinical data. Cauchy integral subtraction was found to be relatively free of artefacts but required more computing time than bilinear interpolation. Both methods may be used with reasonable confidence for the quantification of relative measurements such as left ventricular ejection fraction and myocardial perfusion index but should be avoided if at all possible in the quantification of absolute measurements such as glomerular filtration rate. (author)

  2. Subtractions in the Adler sum rule and violation of charge symmetry

    International Nuclear Information System (INIS)

    Dominguez, C.A.; Moreno, H.; Zepeda, A.

    1976-01-01

    The consequences of a once-subtracted dispersion relation in the derivation of the Adler sum rule are investigated. It is shown that one can expect a breakdown of charge symmetry, of the isotriplet-current hypothesis, and of scaling of the structure functions. These breakdowns are related to the possible presence of a nonzero subtraction function at asymptotic energies and arbitrary q 2 . We also comment about second-class currents and PCAC (partial conservation of axial-vector current) relations

  3. Subtraction of random coincidences in γ-ray spectroscopy: A new approach

    International Nuclear Information System (INIS)

    Pattabiraman, N.S.; Ghugre, S.S.; Basu, S.K.; Garg, U.; Ray, S.; Sinha, A.K.; Zhu, S.

    2006-01-01

    A new analytical method for estimation and subsequent subtraction of random coincidences has been developed. It utilizes the knowledge of the counts in the main diagonal of a background-subtracted symmetric data set for the estimation of the events originating from random coincidences. This procedure has been successfully applied to several data sets. It could be a valuable tool for low-fold data sets, especially for low-cross-section events

  4. Detection of intracranial aneurysms with 64 channel multidetector row computed tomography: Comparison with digital subtraction angiography

    International Nuclear Information System (INIS)

    Pozzi-Mucelli, Fabio; Bruni, Stefano; Doddi, Marco; Calgaro, Antonio; Braini, Massimiliano; Cova, Maria

    2007-01-01

    Purpose: To compare the contribution of 64 channel multidetector row computed tomography angiography (64MDCT-angiography) with digital subtraction angiography (DSA) in the detection of intracranial aneurysms. Methods and materials: Twenty-nine patients (10 males and 19 females, age: 40-84 years; average: 61.9 years) with clinical and imaging findings strongly suggesting the presence of subaracnoid hemorrhage underwent 64MDCT-angiography and DSA with a short interval between the two examinations (less than 12 h-5 days). CT parameters were: 64 mm x 0.5 mm collimation, pitch-0.828 and helical pitch-53. DSA were performed with standard technique (four vessel catheterization) and multiple projections. Axial CT scans as well as maximum intensity projection, volume rendering and multiplanar reformations and angiographic views were independently reviewed by four readers (two for 64MDCT-angiography and two for DSA). Consensus was reached for discordant cases. DSA was considered as the standard of reference. Results: In 29 patients, 28 aneurysms were found (14 patients had 1 aneurysm, 4 patients had 2 aneurysms and 2 patients had 3 aneurysms; in 9 patients no aneurysm were found). 64MDCT-angiography detected 26/28 aneurysms. No false-positive sites were recognized. The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy were, respectively, 92.8, 100, 100, 99.4 and 99.5%. Conclusions: 64MDCT-angiography is helpful in detecting intracranial aneurysms with results similar to those of DSA but with less discomfort and risks for the patients and can be considered for the first line imaging technique. Conventional angiography is still needed in doubtful cases or negative MDCT-angiography associated with a strong clinical suspect

  5. Intravenous digital subtraction angiography and helical computed tomography in evaluation of living renal donors

    International Nuclear Information System (INIS)

    Watarai, Yoshihiko; Usuki, Tomoaki; Takeuchi, Ichiro; Nonomura, Katsuya; Koyanagi, Tomohiko; Kubo, Kozo; Hirano, Tetsuo; Togashi, Masaki; Ohashi, Nobuo

    2001-01-01

    The present study was carried out to evaluate the accuracy of helical computed tomography (CT) and intravenous digital subtraction angiography (IV-DSA) on anatomical assessment of renal vasculature for living renal donors. Forty-two healthy potential renal donors were prospectively evaluated and 35 subsequently underwent donor nephrectomy after helical CT and IV-DSA evaluation. The vascular and non-vascular findings were compared between the findings on helical CT, IV-DSA and surgery. Ten prehilar branches and five accessory renal arteries were found at nephrectomy. Overall, operative findings agreed with the findings by IV-DSA in 89% and by helical CT in 83%. In delineating accessory arteries, IV-DSA had a sensitivity of 60% and specificity of 97%, whereas helical CT had a sensitivity of 40% and specificity of 100%. In delineating prehilar branches, IV-DSA had a sensitivity of 90% and specificity of 100%, whereas helical CT had a sensitivity of 70% and specificity of 100%. Accessory arteries and prehilar branches that were not detected by helical CT or IV-DSA, were less than 2 mm in diameter and did not require vascular reconstruction. Renal veins were delineated in 63% by IV-DSA, whereas they were clearly imaged by helical CT in all cases, including a case with a circumaortic renal vein. Non-vascular findings were obtained in 64% by helical CT, including two renal tumors. None of these findings were obtained by IV-DSA. Helical CT and IV-DSA provide comparably sufficient information on renal artery vasculature. However, helical CT provides significantly more information on venous and non-vascular findings as a single-imaging modality. (author)

  6. K-Edge Subtraction Angiography with Synchrotron X-Rays

    International Nuclear Information System (INIS)

    Giacomini, John C.

    1996-01-01

    The purpose of this project was to utilize dual energy, monochromatic X-rays produced from synchrotrons radiation in order to obtain noninvasive medical imaging. The application of synchrotrons radiation to medical imaging is based on the principle of iodine dichromography, first described by Bertil Jacobson of the Karolinska Institute in 1953. Medical imaging using synchrotrons radiation and K-edge dichromography was pioneered at Stanford University under the leadership of Dr. Ed Rubenstein, and the late Nobel Laureate in Physics, Dr. Robert Hofstadter. With progressive refinements in hardware, clinical-quality images were obtained of human coronary arteries utilizing peripheral injections of iodinated contrast agent. These images even now are far superior to those being presented by investigators using MRI as an imaging tool for coronary arteries. However, new supplies and instruments in the cardiac catheterization laboratory have served to transform coronary angiography into an outpatient procedure, with relatively little morbidity. We extended the principles learned with coronary angiography to noninvasive imaging of the human bronchial tree. For these images, we utilized xenon as the contrast agent, as it has a K-edge very similar to that of iodine. In this case, there is no true competing diagnostic test, and pulmonary neoplasm is an enormous public health concern. In early experiments, we demonstrated remarkably clear images of the human bronchial tree. These images have been shown internationally; however, funding difficulties primarily with the Department of Energy have not allowed for progression of this promising avenue of research. One potential criticism of the project is that in order to obtain these images, we utilized national laboratories. Some have questioned whether this would lead to a practical imaging modality. However, we have shown that the technology exists to allow for construction of a miniature storage ring, with a superconducting

  7. Measurements of image characteristics of DSA installations

    International Nuclear Information System (INIS)

    Busch, H.P.; Strauss, L.G.; Freimarck, R.D.

    1984-01-01

    Measurements for quantifying the image characteristics were carried out on three DSA installations (DVI 1 - Philips, Angiotron - Siemens and DF 3000 - General Eletric). Contrast resolution was measured with a vessel phantom (General Electric) and spatial resolution with a lead grid. A further parameter was the dose entering the image intensifier. The Angiotron was used with an intensifier with 53 cm. diameter and the DF 3000 with temporal subtraction of the video images and the subtraction of dual energy images (hybrid technique). These measurements can be carried out quickly and easily and are a step towards standardisation of measurements of image characteristics of DSA installations. (orig.) [de

  8. Pedicle subtraction osteotomy in elderly patients with degenerative sagittal imbalance.

    Science.gov (United States)

    Cho, Kyu-Jung; Kim, Ki-Tack; Kim, Whoan-Jeang; Lee, Sang-Hoon; Jung, Jae-Hoon; Kim, Young-Tae; Park, Hae-Bong

    2013-11-15

    Retrospective, radiographical analysis. To evaluate pedicle subtraction osteotomy (PSO) as a means of correcting severe degenerative sagittal imbalance in elderly patients. PSO in patients with degenerative sagittal imbalance is likely to cause more complications than in patients with iatrogenic flatback deformity. This study analyzed 34 patients who underwent fusion to the sacrum, with a minimum 2-year follow-up. Age of the patients were in the range from 58 to 73 with the mean at 65.5 years. PSO was performed at one segment in all cases, consisting of L3 (n = 26), L4 (n = 4), L2 (n = 3), and L1 (n = 1). The average number of levels fused was 8.15. Ten patients had structural interbody fusion at the lumbosacral junction. Applying PSO at one segment, the mean correction of the lordotic angle at the osteotomy site was 33.3°, of which the loss of correction (LOC) was 4.0° at the last visit. The correction of lumbar lordosis was 33.7° and the LOC was 8.5°. The sagittal C7 plumb was 215.9 mm before surgery, corrected to 35.1 mm after surgery, and changed to 95.9 mm by the last visit. The correction of the sagittal C7 plumb was 119.9 mm and the LOC was 60.9 mm. There was substantial LOC in lumbar lordosis and sagittal C7 plumb. In 10 patients with addition of posterior lumbar interbody fusion, the LOC of lumbar lordosis was 7.4°, which was less than 9° in those without it. PSO for the correction of degenerative sagittal imbalance in elderly patients resulted in correction of sagittal alignment with a significant LOC of lumbar lordosis and sagittal C7 plumb. The LOC of lumbar lordosis occurred at both the osteotomy and non-osteotomy site. The addition of anterior column support is helpful to maintain correction and reduce complications. N/A.

  9. Selected topics in image science

    International Nuclear Information System (INIS)

    Nalcioglu, O.; Cho, Z.H.

    1984-01-01

    A review of the state of the art in diagnostic imaging via computers. Applications covered include emission tomography, digital radiography, and ultrasound and nuclear magnetic resonance imaging. Contents, abridged: Direct Fourier reconstruction techniques. Radiation detectors for CT instrumentation. Single photon emission computed tomography: potentials and limitations. Matched filtering for digital subtraction angiography

  10. Efficiency of observer brightness discrimination in original and subracted images

    International Nuclear Information System (INIS)

    Swensson, R.G.; Kazda, I.; Nawfel, R.; Judy, P.F.

    1990-01-01

    This paper reports that, for an optimal image calculation, discriminating pairs of objects that differ only in brightness is equivalent to discriminating polarity differences in their subtraction images. This experiment measured and compared how efficiently human observers could perform the two different discriminations posed by such original and subtracted images. Disks of equal size, separated by their diameter, were superimposed on incorrelated, Gaussian noise backgrounds at different contrasts that made the two disks readily visible on the displayed radiographs. The digitally subtracted image-regions containing the two disks of each pair (shifted to registration) produced subtraction images with low-contrast disks that were either brighter or darker than the background. Observer performances in each task (measured by receiver operating characteristic [ROC] analysis) was compared with that of an optimal calculation (cross- correlator)

  11. Dispersed-fringe-accumulation-based left-subtract-right method for fine co-phasing of a dispersed fringe sensor.

    Science.gov (United States)

    Li, Yang; Wang, Shengqian; Rao, Changhui

    2017-05-20

    In this paper, a dispersed-fringe-accumulation (DFA)-based left-subtract-right (LSR) piston estimation method (DFA-LSR), in which the dispersed fringe image is accumulated in the dispersed direction, and then the LSR method is used to estimate the piston error, is proposed for dispersed fringe sensors (DFS) in the fine co-phasing stage. The DFS is usually used to detect the piston errors (optical path difference) between different segmented mirrors or synthetic aperture telescopes. The DFA-LSR makes up for the shortcomings of the main peak position (MPP) method, which suffers from the constant offset in the pixel counts. The analysis and experiment results show that the proposed method can keep relatively better performance even at the condition of poor signal-to-noise ratio, compared with the MPP method in fine co-phasing stage.

  12. 320-Multidetector row whole-head dynamic subtracted CT angiography and whole-brain CT perfusion before and after carotid artery stenting: Technical note

    International Nuclear Information System (INIS)

    San Millan Ruiz, Diego; Murphy, Kieran; Gailloud, Philippe

    2010-01-01

    Introduction: Multidetector CT (MDCT) is increasingly used for the investigation of neurovascular disorders, but restricted z-axis coverage (3.2 cm for 64-MDCT) currently limits perfusion to a small portion of the brain close to the circle of Willis, and precludes dynamic angiographic appreciation of the entire brain circulation. We illustrate the clinical potential of recently developed 320-MDCT extending the z-axis coverage to 16 cm in a patient with symptomatic carotid artery stenosis. Methods: In a 74-year-old patient presenting with critical symptomatic stenosis of the left CCA, pre- and post-carotid artery stenting whole-head subtracted dynamic MDCT angiography and perfusion were obtained in addition to CT angiography of the supra-aortic trunks. Both whole-head subtracted MDCT angiography and perfusion demonstrated delayed left ICA circulation, which normalized after carotid stenting. Discussion: 320-MDCT offers unprecedented z-axis coverage allowing for whole-brain perfusion and subtracted dynamic angiography of the entire intracranial circulation. These innovations can consolidate the role of MDCT as a first intention imaging technique for cerebrovascular disorders, in particular for the acute management of stroke.

  13. Contribution of subtraction ictal SPECT coregistered to MRI to epilepsy surgery. A multicenter study

    International Nuclear Information System (INIS)

    Matsuda, Hiroshi; Matsuda, Kazumi; Nakamura, Fumihiro

    2009-01-01

    A multicenter prospective study was performed to assess the additional value of a subtraction ictal single photon emission computed tomography (SPECT) coregistered to MRI (SISCOM) technique to traditional side-by-side comparison of ictal- and interictal SPECT images in epilepsy surgery. One hundred and twenty-three patients with temporal and extratemporal lobe epilepsy who had undergone epilepsy surgery after evaluation of scalp ictal and interictal electroencephalogram (EEG), MRI, and ictal and interictal SPECT scans were followed up in terms of postsurgical outcome for a period of at least 1 year. Three reviewers localized the epileptogenic focus using ictal and interictal SPECT images first by side-by-side comparison and subsequently by SISCOM. Concordance of the localization of the epileptogenic focus by SPECT diagnosis with the surgical site and inter-observer agreement between reviewers was compared between side-by-side comparison and SISCOM. Logistic regression analysis was performed in predicting the surgical outcome with the dependent variable being the achievement of a good postsurgical outcome and the independent variables using the SISCOM, side-by-side comparison of ictal and interictal SPECT images, MRI, and scalp ictal EEG. The SISCOM presented better concordance in extratemporal lobe epilepsy and less concordance in temporal lobe epilepsy than side-by-side comparison. Inter-observer concordance was higher in SISCOM than in side-by-side comparison. Much higher concordance of the epileptogenic focus by SPECT diagnosis with the surgical site was obtained in patients with good surgical outcome than in those with poor surgical outcome. These differences in concordance between good and poor surgical outcomes were greater in SISCOM than in side-by-side comparison. Logistic regression analysis showed the highest odds ratio of 12.391 (95% confidence interval; 3.319, 46.254) by SISCOM evaluation for concordance of the epileptogenic focus with the surgical site

  14. Improved MDCT monitoring of pelvic myeloma bone disease through the use of a novel longitudinal bone subtraction post-processing algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Horger, Marius; Thaiss, Wolfgang M.; Nikolaou, Konstantin; Kloth, Christopher [Eberhard-Karls-University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Ditt, Hendrik [Sector Imaging and Interventional Radiology, Siemens AG Healthcare, Forchheim (Germany); Weisel, Katja [Eberhard-Karls-University Tuebingen, Department of Internal Medicine II, Tuebingen (Germany); Fritz, Jan [Johns Hopkins University School of Medcine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Liao, Shu [Siemens Medical Solutions, Malvern, PA (United States)

    2017-07-15

    To evaluate the diagnostic performance of a novel CT post-processing software that generates subtraction maps of baseline and follow-up CT examinations in the course of myeloma bone lesions. This study included 61 consecutive myeloma patients who underwent repeated whole-body reduced-dose MDCT at our institution between November 2013 and June 2015. CT subtraction maps classified a progressive disease (PD) vs. stable disease (SD)/remission. Bone subtraction maps (BSMs) only and in combination with 1-mm (BSM+) source images were compared with 5-mm axial/MPR scans. Haematological response categories at follow-up were: complete remission (n = 9), very good partial remission (n = 2), partial remission (n = 17) and SDh (n = 19) vs. PDh (n = 14). Five-millimetre CT scan yielded PD (n = 14) and SD/remission (n = 47) whereas bone subtraction + 1-mm axial scans (BSM+) reading resulted in PD (n = 18) and SD/remission (n = 43). Sensitivity/ specificity/accuracy for 5-mm/1-mm/BSM(alone)/BSM + in ''lesion-by-lesion'' reading was 89.4 %/98.9 %/98.3 %/ 99.5 %; 69.1 %/96.9 %/72 %/92.1 % and 83.8 %/98.4 %/92.1 %/98.3 %, respectively. The use of BSM+ resulted in a change of response classification in 9.8 % patients (n = 6) from SD to PD. BSM reading is more accurate for monitoring myeloma compared to axial scans whereas BSM+ yields similar results with 1-mm reading (gold standard) but by significantly reduced reading time. (orig.)

  15. Improved MDCT monitoring of pelvic myeloma bone disease through the use of a novel longitudinal bone subtraction post-processing algorithm

    International Nuclear Information System (INIS)

    Horger, Marius; Thaiss, Wolfgang M.; Nikolaou, Konstantin; Kloth, Christopher; Ditt, Hendrik; Weisel, Katja; Fritz, Jan; Liao, Shu

    2017-01-01

    To evaluate the diagnostic performance of a novel CT post-processing software that generates subtraction maps of baseline and follow-up CT examinations in the course of myeloma bone lesions. This study included 61 consecutive myeloma patients who underwent repeated whole-body reduced-dose MDCT at our institution between November 2013 and June 2015. CT subtraction maps classified a progressive disease (PD) vs. stable disease (SD)/remission. Bone subtraction maps (BSMs) only and in combination with 1-mm (BSM+) source images were compared with 5-mm axial/MPR scans. Haematological response categories at follow-up were: complete remission (n = 9), very good partial remission (n = 2), partial remission (n = 17) and SDh (n = 19) vs. PDh (n = 14). Five-millimetre CT scan yielded PD (n = 14) and SD/remission (n = 47) whereas bone subtraction + 1-mm axial scans (BSM+) reading resulted in PD (n = 18) and SD/remission (n = 43). Sensitivity/ specificity/accuracy for 5-mm/1-mm/BSM(alone)/BSM + in ''lesion-by-lesion'' reading was 89.4 %/98.9 %/98.3 %/ 99.5 %; 69.1 %/96.9 %/72 %/92.1 % and 83.8 %/98.4 %/92.1 %/98.3 %, respectively. The use of BSM+ resulted in a change of response classification in 9.8 % patients (n = 6) from SD to PD. BSM reading is more accurate for monitoring myeloma compared to axial scans whereas BSM+ yields similar results with 1-mm reading (gold standard) but by significantly reduced reading time. (orig.)

  16. Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Schueltke, Elisabeth [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK (Canada); Department of Neurological Sciences, Walton Medical Centre, University of Liverpool, Liverpool L97 LJ (United Kingdom)], E-mail: e.schultke@usask.ca; Fiedler, Stefan [European Molecular Biology Laboratory (EMBL), Nottkestrasse 85, 22603 Hamburg (Germany); Nemoz, Christian [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Ogieglo, Lissa [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Kelly, Michael E. [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Department of Neurosurgery, Section of Cerebrovascular and Endovascular Neurosurgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH (United States); Crawford, Paul [Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herfordshire AL9 7TA (United Kingdom); Esteve, Francois [INSERM U836-ESRF, 6 rue Horowitz, 38043 Grenoble (France); Brochard, Thierry; Renier, Michel; Requardt, Herwig; Le Duc, Geraldine [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Juurlink, Bernhard [Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK (Canada); Meguro, Kotoo [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada)

    2010-03-15

    Background: K-edge digital subtraction angiography (KEDSA) combined with the tunability of synchrotron beam yields an imaging technique that is highly sensitive to low concentrations of contrast agents. Thus, contrast agent can be administered intravenously, obviating the need for insertion of a guided catheter to deliver a bolus of contrast agent close to the target tissue. With the high-resolution detectors used at synchrotron facilities, images can be acquired at high spatial resolution. Thus, the KEDSA appears particularly suited for studies of neurovascular pathology in animal models, where the vascular diameters are significantly smaller than in human patients. Materials and methods: This feasibility study was designed to test the suitability of KEDSA after intravenous injection of iodine-based contrast agent for use in a pig model. Four adult male pigs were used for our experiments. Neurovascular angiographic images were acquired using KEDSA with a solid state Germanium (Ge) detector at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Results: After intravenous injection of 0.9 ml/kg iodinated contrast agent (Xenetix), the peak iodine concentrations in the internal carotid and middle cerebral arteries reached 35 mg/ml. KEDSA images in radiography mode allowed the visualization of intracranial arteries of less than 1.5 mm diameter.

  17. Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: A feasibility study

    International Nuclear Information System (INIS)

    Schueltke, Elisabeth; Fiedler, Stefan; Nemoz, Christian; Ogieglo, Lissa; Kelly, Michael E.; Crawford, Paul; Esteve, Francois; Brochard, Thierry; Renier, Michel; Requardt, Herwig; Le Duc, Geraldine; Juurlink, Bernhard; Meguro, Kotoo

    2010-01-01

    Background: K-edge digital subtraction angiography (KEDSA) combined with the tunability of synchrotron beam yields an imaging technique that is highly sensitive to low concentrations of contrast agents. Thus, contrast agent can be administered intravenously, obviating the need for insertion of a guided catheter to deliver a bolus of contrast agent close to the target tissue. With the high-resolution detectors used at synchrotron facilities, images can be acquired at high spatial resolution. Thus, the KEDSA appears particularly suited for studies of neurovascular pathology in animal models, where the vascular diameters are significantly smaller than in human patients. Materials and methods: This feasibility study was designed to test the suitability of KEDSA after intravenous injection of iodine-based contrast agent for use in a pig model. Four adult male pigs were used for our experiments. Neurovascular angiographic images were acquired using KEDSA with a solid state Germanium (Ge) detector at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Results: After intravenous injection of 0.9 ml/kg iodinated contrast agent (Xenetix), the peak iodine concentrations in the internal carotid and middle cerebral arteries reached 35 mg/ml. KEDSA images in radiography mode allowed the visualization of intracranial arteries of less than 1.5 mm diameter.

  18. Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: a feasibility study.

    Science.gov (United States)

    Schültke, Elisabeth; Fiedler, Stefan; Nemoz, Christian; Ogieglo, Lissa; Kelly, Michael E; Crawford, Paul; Esteve, Francois; Brochard, Thierry; Renier, Michel; Requardt, Herwig; Le Duc, Geraldine; Juurlink, Bernhard; Meguro, Kotoo

    2010-03-01

    K-edge digital subtraction angiography (KEDSA) combined with the tunability of synchrotron beam yields an imaging technique that is highly sensitive to low concentrations of contrast agents. Thus, contrast agent can be administered intravenously, obviating the need for insertion of a guided catheter to deliver a bolus of contrast agent close to the target tissue. With the high-resolution detectors used at synchrotron facilities, images can be acquired at high spatial resolution. Thus, the KEDSA appears particularly suited for studies of neurovascular pathology in animal models, where the vascular diameters are significantly smaller than in human patients. This feasibility study was designed to test the suitability of KEDSA after intravenous injection of iodine-based contrast agent for use in a pig model. Four adult male pigs were used for our experiments. Neurovascular angiographic images were acquired using KEDSA with a solid state Germanium (Ge) detector at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. After intravenous injection of 0.9 ml/kg iodinated contrast agent (Xenetix), the peak iodine concentrations in the internal carotid and middle cerebral arteries reached 35 mg/ml. KEDSA images in radiography mode allowed the visualization of intracranial arteries of less than 1.5mm diameter. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  19. Intra-arterial digital subtraction portography with a blood-isotonic, non-ionic, dimeric contrast medium

    International Nuclear Information System (INIS)

    Minakuchi, Kazuo; Tamaoka, Koichi; Nishio, Hiroshi; Matsuo, Ryoichi; Takada, Keiji; Morimoto, Atsuko; Toyoshima, Masami; Murata, Katsuko; Onoyama, Yasuto

    1993-01-01

    Intra-arterial digital subtraction portography (IA-DSP) with a blood-isotonic, non-ionic, dimeric contrast medium was carried out in 27 patients with hepatocellular carcinoma. It was possible to obtain images of excellent or good quality of the portal vein and its bilateral main branches in all patients. The third-order branches of the portal vein in the right lobe could be identified in all patients, and images of excellent or good quality were obtained in a mean of 80.2% of patients. Images of third-order branches in the left lobe were of lower quality than those of third-order branches in the right lobe; in particular, images obtained were of poor quality for 27.3% of the medial branches of the left lobe. It was impossible to identify the caudal branches in almost all patients. The side effects of IA-DSP, pain and sensations of heat were very mild; only one patient complained of mild pain, while 18 patients (69.2%) complained of no sensations of heat whatsoever. (author)

  20. Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries.

    Science.gov (United States)

    Seymour, H R; Matson, M B; Belli, A M; Morgan, R; Kyriou, J; Patel, U

    2001-02-01

    Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.

  1. Informed baseline subtraction of proteomic mass spectrometry data aided by a novel sliding window algorithm.

    Science.gov (United States)

    Stanford, Tyman E; Bagley, Christopher J; Solomon, Patty J

    2016-01-01

    Proteomic matrix-assisted laser desorption/ionisation (MALDI) linear time-of-flight (TOF) mass spectrometry (MS) may be used to produce protein profiles from biological samples with the aim of discovering biomarkers for disease. However, the raw protein profiles suffer from several sources of bias or systematic variation which need to be removed via pre-processing before meaningful downstream analysis of the data can be undertaken. Baseline subtraction, an early pre-processing step that removes the non-peptide signal from the spectra, is complicated by the following: (i) each spectrum has, on average, wider peaks for peptides with higher mass-to-charge ratios ( m / z ), and (ii) the time-consuming and error-prone trial-and-error process for optimising the baseline subtraction input arguments. With reference to the aforementioned complications, we present an automated pipeline that includes (i) a novel 'continuous' line segment algorithm that efficiently operates over data with a transformed m / z -axis to remove the relationship between peptide mass and peak width, and (ii) an input-free algorithm to estimate peak widths on the transformed m / z scale. The automated baseline subtraction method was deployed on six publicly available proteomic MS datasets using six different m/z-axis transformations. Optimality of the automated baseline subtraction pipeline was assessed quantitatively using the mean absolute scaled error (MASE) when compared to a gold-standard baseline subtracted signal. Several of the transformations investigated were able to reduce, if not entirely remove, the peak width and peak location relationship resulting in near-optimal baseline subtraction using the automated pipeline. The proposed novel 'continuous' line segment algorithm is shown to far outperform naive sliding window algorithms with regard to the computational time required. The improvement in computational time was at least four-fold on real MALDI TOF-MS data and at least an order of

  2. Value and limitation of digital subtraction angiography for assessment of myocardial perfusion with varying coronary stenosis

    International Nuclear Information System (INIS)

    Ohtani, Nozomu

    1988-01-01

    We examined the value of digital subtraction angiography (DSA) for the assessment of regional myocardial perfusion by comparing with regional myocardial function in 10 anesthetized dogs. With varying degrees of reduction in left circumflex coronary artery (LCX) blood flow (CBF:categories of stenosis (S1-S5)), myocardial perfusion was assessed by injecting the contrast medium(1ml by power injector) selectively into LCX, and the regional myocardium with contrast was imaged with DSA. We recorded aortic pressure (AOP) and systolic wall thickening (%WTh: sonomicrometry) in the left ventricular posterior wall simultaneously with cine pulse. On the time-density curve obtained from the myocardial regin of interest, we calculated a time interval from the contrast injection to peak concentration (TPC) and exponential washout rate (T). Under varying LCX stenosis, there were no significant change of heart rate and mean AOP and a significant linear correlations were found between %WTh and both 1/TPC(r=0.51)and 1/T(r=0.55). At S1(CBF:100-90% of control), neither %WTh nor 1/TPC differed from control, but 1/T was significantly decreased (80% of contral p<0.01). At S3(CRF:79-60%) to S5(CBF:39-0%), all%WTh, 1/TPC and 1/T were significantly decreased from control (all p<0.01), however, at S5(CBF:39-0%) the value of 1/TPC(71% of control) and 1/T(33%) were not different from that at S4, whereas %WTh was markedly reduced and took place to systolic thinning.. Therefore, in critical coronary stenosis, 1/T was more sensitive than 1/TPC or wall dynamics for assessing myocardial perfusion, however, these indices from DSA had a considerable limitation for evaluating the severity of myocardial ischemia when CBF was markedly reduced. (author)

  3. A method for subtraction of the extrarenal 'background' in dynamic 131I-hippurate renoscintigraphy

    International Nuclear Information System (INIS)

    Mlodkowska, E.; Liniecki, J.; Surma, M.

    1979-01-01

    Using a Toshiba GC-401 gamma camera with MDS computer Trinary a new method was developed for subtracting the extrarenal (extracanalicular) 'background' from the count rate recorded over the kidneys after intravenous administration of 131 I-hippurate. Mean subtraction factors of the 'blood' activity curve were calculated from a study of 27 patients who were given 51 Cr-HSA for purposes of conventional renography with 'background' subtraction. The values of the mean subtraction factors anti Fsub(R,L) for the right and left kidney, by which a blood count rate should be multiplied amounted to 0.86 +- 0.12 and 0.79 +- 0.13, respectively. A comparison of the coefficients of variation of the pure renal signal when mean vs. individually determined subtraction factors were used, and the verification of the method in unilaterally nephrectomized patients have demonstrated that determination of the factors, anti Fsub(R,L), for each patient individually is not required and sufficient precision can be obtained by using the method and factors reported in this study. (orig.) [de

  4. Dose related, comparative evaluation of a novel bone-subtraction algorithm in 64-row cervico-cranial CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Siebert, E.; Bohner, G. [Department of Neuroradiology, Charite Universitary Medicine Berlin (Germany); Dewey, M.; Bauknecht, C. [Department of Radiology, Charite Universitary Medicine Berlin (Germany); Klingebiel, R. [Department of Neuroradiology, Charite Universitary Medicine Berlin (Germany)], E-mail: randolf.klingebiel@charite.de

    2010-01-15

    Purpose: Comparative evaluation of a low-dose scan protocol for a novel bone-subtraction (BS) algorithm, applicable to 64-row cervico-cranial (cc) CT angiography (MSCTA). Methods and patients: BS algorithm assessment was performed in cadaveric phantom studies by stepwise variation of tube current and head malrotation using a 64-row CT scanner. In order to define minimum dose requirements and the rotation correction capacity, a low dose BS MSCTA protocol was defined and evaluated in 12 patients in comparison to a common manual bone removal algorithm. Standard MIPs of both modalities were evaluated in a blinded manner by two neuroradiologists for image quality composed, of vessel contour sharpness and bony vessel superposition, by using a five-point score each. Effective Dose (E) and data post-processing times were defined. Results: In experimental studies prescan tube current could be cut down to one-sixth of post-contrast scan doses without compromise of bone-subtraction whereas incomplete subtraction appeared from four degrees head malrotation on. Prescan E amounted to additional 1.1 mSv (+25%) in clinical studies. BS MSCTA performed significantly superior in terms of bony superposition for vascular segments C3-C7 (p < 0.001), V1-V2, V3-V4 (p < 0.05, p < 0.001 respectively) and the ophthalmic artery (p < 0.05), whereas vessel contour sharpness in BS MSCTA only proved superior for arterial segments V3-V4 (p < 0.001) and C3-C7 (p < 0.001). MBR MSCTA received higher ratings in vessel contour sharpness for C1-C2 (p < 0.001), callosomarginal artery (p < 0.001), M1, M2, M3 (p < 0.001 each) and the basilar artery (p < 0.001). Reconstruction times amounted to an average of 1.5 (BS MSCTA) and 3 min (MBR MSCTA) respectively. Conclusion: The novel BS algorithm provides superior skull base artery visualisation as compared to common manual bone removal algorithms, increasing the Effective Dose by one-fourth. Yet, inferior vessel contour sharpness was noted intracranially, thus

  5. Dose related, comparative evaluation of a novel bone-subtraction algorithm in 64-row cervico-cranial CT angiography

    International Nuclear Information System (INIS)

    Siebert, E.; Bohner, G.; Dewey, M.; Bauknecht, C.; Klingebiel, R.

    2010-01-01

    Purpose: Comparative evaluation of a low-dose scan protocol for a novel bone-subtraction (BS) algorithm, applicable to 64-row cervico-cranial (cc) CT angiography (MSCTA). Methods and patients: BS algorithm assessment was performed in cadaveric phantom studies by stepwise variation of tube current and head malrotation using a 64-row CT scanner. In order to define minimum dose requirements and the rotation correction capacity, a low dose BS MSCTA protocol was defined and evaluated in 12 patients in comparison to a common manual bone removal algorithm. Standard MIPs of both modalities were evaluated in a blinded manner by two neuroradiologists for image quality composed, of vessel contour sharpness and bony vessel superposition, by using a five-point score each. Effective Dose (E) and data post-processing times were defined. Results: In experimental studies prescan tube current could be cut down to one-sixth of post-contrast scan doses without compromise of bone-subtraction whereas incomplete subtraction appeared from four degrees head malrotation on. Prescan E amounted to additional 1.1 mSv (+25%) in clinical studies. BS MSCTA performed significantly superior in terms of bony superposition for vascular segments C3-C7 (p < 0.001), V1-V2, V3-V4 (p < 0.05, p < 0.001 respectively) and the ophthalmic artery (p < 0.05), whereas vessel contour sharpness in BS MSCTA only proved superior for arterial segments V3-V4 (p < 0.001) and C3-C7 (p < 0.001). MBR MSCTA received higher ratings in vessel contour sharpness for C1-C2 (p < 0.001), callosomarginal artery (p < 0.001), M1, M2, M3 (p < 0.001 each) and the basilar artery (p < 0.001). Reconstruction times amounted to an average of 1.5 (BS MSCTA) and 3 min (MBR MSCTA) respectively. Conclusion: The novel BS algorithm provides superior skull base artery visualisation as compared to common manual bone removal algorithms, increasing the Effective Dose by one-fourth. Yet, inferior vessel contour sharpness was noted intracranially, thus

  6. [The backgroud sky subtraction around [OIII] line in LAMOST QSO spectra].

    Science.gov (United States)

    Shi, Zhi-Xin; Comte, Georges; Luo, A-Li; Tu, Liang-Ping; Zhao, Yong-Heng; Wu, Fu-Chao

    2014-11-01

    At present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around [OIII] line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem that the width of Hβ-[OIII] line is effected by the backgroud sky subtraction. The exprimental results show that, for different redshift quasars, the spectral quality has been significantly improved using our method relative to the original batch program by LAMOST. It provides a complementary solution for the small part of LAMOST spectra which are not well handled by LAMOST 2D pipeline. Meanwhile, This method has been used in searching for candidates of double-peaked Active Galactic Nuclei.

  7. Aggression-related brain function assessed with the Point Subtraction Aggression Paradigm in fMRI

    DEFF Research Database (Denmark)

    Skibsted, Anine P; Cunha-Bang, Sofi da; Carré, Justin M

    2017-01-01

    The Point Subtraction Aggression Paradigm (PSAP) measures aggressive behavior in response to provocations. The aim of the study was to implement the PSAP in a functional neuroimaging environment (fMRI) and evaluate aggression-related brain reactivity including response to provocations and associa......The Point Subtraction Aggression Paradigm (PSAP) measures aggressive behavior in response to provocations. The aim of the study was to implement the PSAP in a functional neuroimaging environment (fMRI) and evaluate aggression-related brain reactivity including response to provocations...... and associations with aggression within the paradigm. Twenty healthy participants completed two 12-min PSAP sessions within the scanner. We evaluated brain responses to aggressive behavior (removing points from an opponent), provocations (point subtractions by the opponent), and winning points. Our results showed...... with the involvement of these brain regions in emotional and impulsive behavior. Striatal reactivity may suggest an involvement of reward during winning and stealing points....

  8. Enhancing quantum entanglement for continuous variables by a coherent superposition of photon subtraction and addition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su-Yong; Kim, Ho-Joon [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Ji, Se-Wan [School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-012 (Korea, Republic of); Nha, Hyunchul [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Institute fuer Quantenphysik, Universitaet Ulm, D-89069 Ulm (Germany)

    2011-07-15

    We investigate how the entanglement properties of a two-mode state can be improved by performing a coherent superposition operation ta+ra{sup {dagger}} of photon subtraction and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each mode. We show that the degree of entanglement, the Einstein-Podolsky-Rosen-type correlation, and the performance of quantum teleportation can be all enhanced for the output state when the coherent operation is applied to a two-mode squeezed state. The effects of the coherent operation are more prominent than those of the mere photon subtraction a and the addition a{sup {dagger}} particularly in the small-squeezing regime, whereas the optimal operation becomes the photon subtraction (case of r=0) in the large-squeezing regime.

  9. Spectral Subtraction Approach for Interference Reduction of MIMO Channel Wireless Systems

    Directory of Open Access Journals (Sweden)

    Tomohiro Ono

    2005-08-01

    Full Text Available In this paper, a generalized spectral subtraction approach for reducing additive impulsive noise, narrowband signals, white Gaussian noise and DS-CDMA interferences in MIMO channel DS-CDMA wireless communication systems is investigated. The interference noise reduction or suppression is essential problem in wireless mobile communication systems to improve the quality of communication. The spectrum subtraction scheme is applied to the interference noise reduction problems for noisy MIMO channel systems. The interferences in space and time domain signals can effectively be suppressed by selecting threshold values, and the computational load with the FFT is not large. Further, the fading effects of channel are compensated by spectral modification with the spectral subtraction process. In the simulations, the effectiveness of the proposed methods for the MIMO channel DS-CDMA is shown to compare with the conventional MIMO channel DS-CDMA.

  10. A simultaneous all-optical half/full-subtraction strategy using cascaded highly nonlinear fibers

    Science.gov (United States)

    Singh, Karamdeep; Kaur, Gurmeet; Singh, Maninder Lal

    2018-02-01

    Using non-linear effects such as cross-gain modulation (XGM) and cross-phase modulation (XPM) inside two highly non-linear fibres (HNLF) arranged in cascaded configuration, a simultaneous half/full-subtracter is proposed. The proposed simultaneous half/full-subtracter design is attractive due to several features such as input data pattern independence and usage of minimal number of non-linear elements i.e. HNLFs. Proof of concept simulations have been conducted at 100 Gbps rate, indicating fine performance, as extinction ratio (dB) > 6.28 dB and eye opening factors (EO) > 77.1072% are recorded for each implemented output. The proposed simultaneous half/full-subtracter can be used as a key component in all-optical information processing circuits.

  11. Venous digital subtraction angiography for diagnosis of renal artery stenosis in arterial hypertony

    International Nuclear Information System (INIS)

    Schoerner, W.; Kempter, H.; Banzer, D.; Aviles, C.; Weiss, T.; Felix, R.

    1984-01-01

    Venous digital subtraction angiography was performed in 248 patients for the diagnosis of renal arterial stenosis. In 88% of the investigations the stenosis could be found. Comparison of digital angiography and conventional angiography was made for 57 renal arteries (25 investigations). In 52 renal arteries we found the same results with both methods, in 5 renal arteries we found the same results with both methods, in 5 renal arteries the digital angiography showed false positive results. The spatial resolution of digital subtraction angiography is sufficient for the correct diagnosis of significant renal arterial stenosis. With regard to the lower invasion of digital subtraction angiography compared to conventional angiography the first method should be used for clarification of renal arterial hypertension. (orig.)

  12. Continuous-variable measurement-device-independent quantum key distribution with photon subtraction

    Science.gov (United States)

    Ma, Hong-Xin; Huang, Peng; Bai, Dong-Yun; Wang, Shi-Yu; Bao, Wan-Su; Zeng, Gui-Hua

    2018-04-01

    It has been found that non-Gaussian operations can be applied to increase and distill entanglement between Gaussian entangled states. We show the successful use of the non-Gaussian operation, in particular, photon subtraction operation, on the continuous-variable measurement-device-independent quantum key distribution (CV-MDI-QKD) protocol. The proposed method can be implemented based on existing technologies. Security analysis shows that the photon subtraction operation can remarkably increase the maximal transmission distance of the CV-MDI-QKD protocol, which precisely make up for the shortcoming of the original CV-MDI-QKD protocol, and one-photon subtraction operation has the best performance. Moreover, the proposed protocol provides a feasible method for the experimental implementation of the CV-MDI-QKD protocol.

  13. Simultaneous optical digital half-subtraction and -addition using SOAs and a PPLN waveguide.

    Science.gov (United States)

    McGeehan, John E; Kumar, Saurabh; Willner, Alan E

    2007-04-30

    We demonstrate an optical half-subtracter and half-adder module that performs simultaneous bit-wise subtraction and addition of two 5 Gbit/s RZ data streams. We generate Borrow (/X*Y) and Difference/Sum (X plus sign in circleY, or XOR) outputs using cross-gain modulation (XGM) in two parallel SOAs. Taking advantage of the gain saturation inherent to SOAs, we generate two signals, /X*Y, and X*/Y, and combine them using a passive optical coupler to generate the XOR Difference/Sum output. We use difference-frequency-generation-based lambda-conversion in a PPLN waveguide to generate the Carry (X*Y) output. The PPLN waveguide allows bit-synchronous wavelength shifting, is wide-bandwidth, and offers no intrinsic chirp. Our module uses three active elements to perform simultaneous half-subtraction and addition, and carries a maximum power penalty of 1.0 dB.

  14. Multislice CT Angiography in Renal Artery Stent Evaluation: Prospective Comparison with Intra-Arterial Digital Subtraction Angiography

    International Nuclear Information System (INIS)

    Raza, Syed A.; Chughtai, Aamer R.; Wahba, Mona; Cowling, Mark G.; Taube, David; Wright, Andrew R.

    2004-01-01

    Purpose: To assess the role of multislice computed tomography angiography (MCTA) in the evaluation of renal artery stents, using intra-arterial digital subtraction angiography (DSA) as the gold standard. Methods: Twenty consecutive patients (15 men, 5 women) with 23 renal artery stents prospectively underwent both MCTA and DSA. Axial images, multiplanar reconstructions and maximum intensity projection images were used for diagnosis. The MCTA and DSA images were each interpreted without reference to the result of the other investigation. Results:The three cases of restenosis on DSA were detected correctly by MCTA; in 19 cases where MCTA showed a fully patent stent, the DSA was also negative. Sensitivity and negative predictive value (NPV) of MCTA were therefore 100%. In four cases, MCTA showed apparently minimal disease which was not shown on DSA. These cases are taken as false positive giving a specificity of 80% and a positive predictive value of 43%. Conclusion: The high sensitivity and NPV suggest MCTA may be useful as a noninvasive screen for renal artery stentrestenosis. MCTA detected mild disease in a few patients which was not confirmed on angiography

  15. Evaluation of the minimum iodine concentration for contrast-enhanced subtraction mammography

    International Nuclear Information System (INIS)

    Baldelli, P; Bravin, A; Maggio, C Di; Gennaro, G; Sarnelli, A; Taibi, A; Gambaccini, M

    2006-01-01

    Early manifestation of breast cancer is often very subtle and is displayed in a complex and variable pattern of normal anatomy that may obscure the disease. The use of dual-energy techniques, that can remove the structural noise, and contrast media, that enhance the region surrounding the tumour, could help us to improve the detectability of the lesions. The aim of this work is to investigate the use of an iodine-based contrast medium in mammography with two different double exposure techniques: K-edge subtraction mammography and temporal subtraction mammography. Both techniques have been investigated by using an ideal source, like monochromatic beams produced at a synchrotron radiation facility and a clinical digital mammography system. A dedicated three-component phantom containing cavities filled with different iodine concentrations has been developed and used for measurements. For each technique, information about the minimum iodine concentration, which provides a significant enhancement of the detectability of the pathology by minimizing the risk due to high dose and high concentration of contrast medium, has been obtained. In particular, for cavities of 5 and 8 mm in diameter filled with iodine solutions, the minimum concentration needed to obtain a contrast-to-noise ratio of 5 with a mean glandular dose of 2 mGy has been calculated. The minimum concentrations estimated with monochromatic beams and K-edge subtraction mammography are 0.9 mg ml -1 and 1.34 mg ml -1 for the biggest and smallest details, respectively, while for temporal subtraction mammography they are 0.84 mg ml -1 and 1.31 mg ml -1 . With the conventional clinical system the minimum concentrations for the K-edge subtraction mammography are 4.13 mg ml -1 (8 mm diameter) and 5.75 mg ml -1 (5 mm diameter), while for the temporal subtraction mammography they are 1.01 mg ml -1 (8 mm diameter) and 1.57 mg ml -1 (5 mm diameter)

  16. CT Angiography of Peripheral Arterial Disease by 256-Slice Scanner: Accuracy, Advantages and Disadvantages Compared to Digital Subtraction Angiography.

    Science.gov (United States)

    Mishra, Atul; Jain, Narendra; Bhagwat, Anand

    2017-07-01

    Peripheral arterial occlusive disease (PAOD) may cause disabling claudication or critical limb ischemia. Multidetector computed tomography (CT) technology has evolved to the level of 256-slice CT scanners which has significantly improved the spatial and temporal resolution of the images. This has provided the capability of chasing the contrast bolus at a fast speed enabling angiographic imaging of long segments of the body. These images can be reconstructed in various planes and various modes for detailed analysis of the peripheral vascular diseases which helps in making treatment decision. The aim of this retrospective study was to compare the CT angiograms (CTAs) of all cases of PAOD done by 256-slice CT scanner at a tertiary care vascular center and comparing these images with the digital subtraction angiograms (DSAs) of these patients. The retrospective study included 53 patients who underwent both CTA and DSA at our center over a period of 3 years from March 2013 to March 2016. The CTA showed high sensitivity (93%) and specificity (92.7%) for overall assessment of degree of stenosis in a vascular segment in cases of aortic and lower limb occlusive disease. The assessment of lesions of infrapopliteal segment was comparatively inferior (sensitivity 91.6%, accuracy 73.3%, and positive predictive value 78.5%), more so in the presence of significant calcification. The advantages of CTA were its noninvasive nature, ability to image large area of body, almost no adverse effects to the patients, and better assessment of vessel wall disease. However, the CTA assessment of collaterals was inferior with a sensitivity of only 62.7% as compared to DSA. Overall, 256-slice CTA provides fast and accurate imaging of vascular tree which can restrict DSA only in few selected cases as a problem-solving tool where clinico-radiological mismatch is present.

  17. Subtracted Dispersion Relations for In-medium Meson Correlators in QCD Sum Rules

    Energy Technology Data Exchange (ETDEWEB)

    Florkowski, W; Broniowski, W [The H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

    1999-01-01

    We analyze subtracted dispersion relations for meson correlators at finite baryon density and temperature. Such relations are needed for QCD sum rules. We point out that importance of scattering terms, as well as finite, well-defined subtraction constants. Both are necessary for consistency, in particular for the equality of the longitudinal and transverse correlators in the limit of the vanishing three-momentum of mesons relative to the medium. We present detailed calculations in various mesonic channels of the Fermi gas of nucleons. (author)

  18. A single injection technique for subtraction of blood background in 131I-hippuran renograms

    International Nuclear Information System (INIS)

    Rutland, M.D.

    1979-01-01

    A method of subtracting blood background during probe-renography is presented which does not require a prior injection of RIHSA and which produces results approximately 11% higher than the RIHSA method. The new method treats the renogram up to two-and-a-half minutes as a combination of a fraction of the blood curve and a fraction of the integral of the blood curve. Analysis of the data, using either a computer or a programmed calculator, enables these two fractions to be calculated, hence producing the 'background subtraction factor' and the 'uptake constant'. (author)

  19. Higgs boson production in association with a jet using jettiness subtraction

    Directory of Open Access Journals (Sweden)

    Radja Boughezal

    2015-09-01

    Full Text Available We use the recently proposed jettiness-subtraction scheme to provide the complete calculation of Higgs boson production in association with a jet in hadronic collisions through next-to-next-to-leading order in perturbative QCD. This method exploits the observation that the N-jettiness event-shape variable completely describes the singularity structure of QCD when final-state colored particles are present. Our results are in agreement with a recent computation of the gg and qg partonic initial states based on sector-improved residue subtraction. We present phenomenological results for both fiducial cross sections and distributions at the LHC.

  20. Speech Enhancement by Multichannel Crosstalk Resistant ANC and Improved Spectrum Subtraction

    Directory of Open Access Journals (Sweden)

    Zeng Qingning

    2006-01-01

    Full Text Available A scheme combining multichannel crosstalk resistant adaptive noise cancellation (MCRANC algorithm and improved spectrum subtraction (ISS algorithm is presented to enhance noise carrying speech signals. The scheme would permit locating the microphones in close proximity by virtue of using MCRANC which has the capability of removing the crosstalk effect. MCRANC would also permit canceling out nonstationary noise and making the residual noise more stationary for further treatment by ISS algorithm. Experimental results have indicated that this scheme outperforms many commonly used techniques in the sense of SNR improvement and music effect reduction which is an inevitable byproduct of the spectrum subtraction algorithm.

  1. Similarity renormalization group evolution of N N interactions within a subtractive renormalization scheme

    Directory of Open Access Journals (Sweden)

    Durães F.O.

    2010-04-01

    Full Text Available We apply the similarity renormalization group (SRG approach to evolve a nucleon-nucleon (N N interaction in leading-order (LO chiral effective field theory (ChEFT, renormalized within the framework of the subtracted kernel method (SKM. We derive a fixed-point interaction and show the renormalization group (RG invariance in the SKM approach. We also compare the evolution of N N potentials with the subtraction scale through a SKM RG equation in the form of a non-relativistic Callan-Symanzik (NRCS equation and the evolution with the similarity cutoff through the SRG transformation.

  2. Parathyroid localizlation by 201Tl-99mTc subtraction scintigraphy

    International Nuclear Information System (INIS)

    Rademaker, P.; Meijer, S.; Piers, D.A.

    1990-01-01

    Subtraction scintigraphy with 201 Tl and 99m Tc for parathyroid localization was performed preoperatively in 13 patients with chronic renal failure and secondary hyperparathyroidism. Twenty of the 37 examined pathological glands were predicted correctly (sensitivity 54%). In 3 patients with recurrent hyperparathyroidism after surgery all pathological glands found at second operation had been detected correctly by subtraction scintigraphy. We conclude that this localization method has a limited value when used prior to first neck exploration in secondary hyperparathyroidism. In persistent hyperparathyroidism after surgery it may play a useful role in localizing missed and ectopic glands. (author)

  3. Subtraction method of computing QCD jet cross sections at NNLO accuracy

    Science.gov (United States)

    Trócsányi, Zoltán; Somogyi, Gábor

    2008-10-01

    We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.

  4. Subtraction method of computing QCD jet cross sections at NNLO accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Trocsanyi, Zoltan [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen P.O.Box 51 (Hungary)], E-mail: Zoltan.Trocsanyi@cern.ch; Somogyi, Gabor [University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)], E-mail: sgabi@physik.unizh.ch

    2008-10-15

    We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.

  5. Development of low-cost digital subtraction angiography system

    International Nuclear Information System (INIS)

    Ando, Yutaka; Kobayashi, Takeshi; Imai, Yutaka; Yagishita, Akira; Kunieda, Etsuo.

    1983-01-01

    We developed a simple and low-cost DSA system. This system consists of a conventional fluoroscopic equipment for the GI tract and a mini-computer (GAMMA-11) which are connected each other with a video-disc recorder. The uniqueness of our system are 1. low-cost, 2. low-radiation dose, 3. off-line processing, 4. flexibility of software. The analysis of the time-density curve and image processing will bring us a more usefull information than DSA alone. (author)

  6. Temporal Subtraction of Digital Breast Tomosynthesis Images for Improved Mass Detection

    National Research Council Canada - National Science Library

    Li, Christina M

    2007-01-01

    Digital breast tomosynthesis (DBT) strives to overcome the obstacles presented in conventional 2D mammography by taking multiple projections over a fixed angle and reconstructing volumetric data isolates overlying anatomy...

  7. Feasibility of coronary calcium and stent image subtraction using 320-detector row CT angiography

    DEFF Research Database (Denmark)

    Fuchs, Andreas; Kühl, J Tobias; Chen, Marcus Y

    2015-01-01

    BACKGROUND: The reader confidence and diagnostic accuracy of coronary CT angiography (CCTA) can be compromised by the presence of calcified plaques and stents causing blooming artifacts. Compared to conventional invasive coronary angiography (ICA), this may cause an overestimation of stenosis....... We defined target segments on CCTAconv as motion-free coronary segments with calcification or stent and low reader confidence. The effect of CCTAsub was assessed. No approval from the ethics committee was required according to Danish law. RESULTS: A total of 76 target segments were identified...

  8. Addition Table of Colours: Additive and Subtractive Mixtures Described Using a Single Reasoning Model

    Science.gov (United States)

    Mota, A. R.; Lopes dos Santos, J. M. B.

    2014-01-01

    Students' misconceptions concerning colour phenomena and the apparent complexity of the underlying concepts--due to the different domains of knowledge involved--make its teaching very difficult. We have developed and tested a teaching device, the addition table of colours (ATC), that encompasses additive and subtractive mixtures in a single…

  9. Application of the singularity subtraction method for (d,p) reactions on light nuclei

    International Nuclear Information System (INIS)

    Borbely, I.

    1974-01-01

    It is shown that the method of subtraction the nearest singularity can be used successfully for data processing of (d,p) reactions. The data on the nuclear structure, thus obtained, can then be used for a more efficient study of the reaction mechanism with the use of traditional methods

  10. Misconception on Addition and Subtraction of Fraction at Primary School Students in Fifth-Grade

    Science.gov (United States)

    Trivena, V.; Ningsih, A. R.; Jupri, A.

    2017-09-01

    This study aims to investigate the mastery concept of the student in mathematics learning especially in addition and subtraction of fraction at primary school level. By using qualitative research method, the data were collected from 23 grade five students (10-11-year-old). Instruments included a test, that is accompanied by Certainty Response Index (CRI) and interview with students and teacher. The result of the test has been obtained, then processed by analyzing the student’s answers for each item and then grouped by the CRI categories that combined with the results of the interview with students and teacher. The results showed that student’s mastery-concept on additional and subtraction dominated by category ‘misconception’. So, we can say that mastery-concept on addition and subtraction of fraction at fifth-grade students is still low. Finally, the impact can make most of primary student think that learning addition and subtraction of fraction in mathematics is difficult.

  11. Infinity subtraction in a quantum field theory of charges and monopoles

    International Nuclear Information System (INIS)

    Panagiotakopoulos, C.

    1982-03-01

    Subtraction of ultraviolet infinities in Zwanziger's local quantum field theory of charges and monopoles is described. It involves an infinite number of graphs. The whole programme rests on the assumption that the infinite summations involved do not give rise to pathological situations and the Ward identities are satisfied even after the string cancellations. The resulting finite theory is Lorentz invariant. (author)

  12. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

    Science.gov (United States)

    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  13. Application of digital subtraction angiography in disease of large cardiac vessel

    Energy Technology Data Exchange (ETDEWEB)

    Arisawa, Jun; Sone, Shusuke; Morimoto, Shizuo; Ikezoe, Junpei; Higashibara, Tokuro; Hanayama, Masayuki

    1983-06-01

    Digital subtraction angiography (DSA) was performed in 31 cases of disease of large cardiac vessel. DSA was useful for the diagnosis of aortic aneurysm and malformation of large vessels, follow-up after A-C bypass operation and Blalock's shunt operation for tetralogy of Fallot and as an adjuvant modality in cardiac catheterization.

  14. Application of digital subtraction angiography in disease of large cardiac vessel

    International Nuclear Information System (INIS)

    Arisawa, Jun; Sone, Shusuke; Morimoto, Shizuo; Ikezoe, Junpei; Higashibara, Tokuro; Hanayama, Masayuki

    1983-01-01

    Digital subtraction angiography (DSA) was performed in 31 cases of disease of large cardiac vessel. DSA was useful for the diagnosis of aortic aneurysm and malformation of large vessels, follow-up after A-C bypass operation and Blalock's shunt operation for tetralogy of Fallot and as an adjuvant modality in cardiac catheterization. (Chiba, N.)

  15. [X-ray semiotics of sialolithiasis in functional digital subtraction sialography].

    Science.gov (United States)

    Iudin, L A; Kondrashin, S A; Afanas'ev, V V; Shchipskiĭ, A V

    1995-01-01

    Twenty-seven patients with sialolithiasis were examined using functional subtraction sialography developed by the authors. Differential diagnostic signs characterizing the degree of involvement of the salivary gland were defined. High efficacy of the method helps correctly plan the treatment strategy.

  16. On Semiotics and Jumping Frogs: The Role of Gesture in the Teaching of Subtraction

    Science.gov (United States)

    Farrugia, Marie Therese

    2017-01-01

    In this article, I describe a research/teaching experience I undertook with a class of 5-year-old children in Malta. The topic was subtraction on the number line. I interpret the teaching/learning process through a semiotic perspective. In particular, I highlight the role played by the gesture of forming "frog jumps" on the number line.…

  17. Geometrical accuracy of metallic objects produced with additive or subtractive manufacturing: A comparative in vitro study.

    Science.gov (United States)

    Braian, Michael; Jönsson, David; Kevci, Mir; Wennerberg, Ann

    2018-04-06

    To evaluate the accuracy and precision of objects produced by additive manufacturing systems (AM) for use in dentistry and to compare with subtractive manufacturing systems (SM). Ten specimens of two geometrical objects were produced by five different AM machines and one SM machine. Object A mimics an inlay-shaped object, while object B imitates a four-unit bridge model. All the objects were sorted into different measurement dimensions (x, y, z), linear distances, angles and corner radius. None of the additive manufacturing or subtractive manufacturing groups presented a perfect match to the CAD file with regard to all parameters included in the present study. Considering linear measurements, the precision for subtractive manufacturing group was consistent in all axes for object A, presenting results of additive manufacturing groups had consistent precision in the x-axis and y-axis but not in the z-axis. With regard to corner radius measurements, the SM group had the best overall accuracy and precision for both objects A and B when compared to the AM groups. Within the limitations of this in vitro study, the conclusion can be made that subtractive manufacturing presented overall precision on all measurements below 0.050mm. The AM machines also presented fairly good precision, additive techniques are now being implemented. Thus all these production techniques need to be tested, compared and validated. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

  18. Addition and Subtraction but Not Multiplication and Division Cause Shifts of Spatial Attention

    Directory of Open Access Journals (Sweden)

    Mengjin Li

    2018-05-01

    Full Text Available Many studies have shown that solving addition and subtraction problems can induce overt shifts of spatial attention. In particular, right-side targets are detected faster than left-side targets when preceded by an addition operation, while left-side targets are detected faster than right-side targets when preceded by a subtraction operation. However, the interaction between space and arithmetic in multiplication or division is hardly studied and remains controversial. In order to make a strong case for the interaction between space and mental arithmetic, we attempted to replicate the spatial-arithmetic association in addition and subtraction (Experiment 1, and at the same time investigated whether shift of spatial attention would also be induced by multiplication or division operations (Experiment 2. We found that solving addition problems facilitated the detection of right-side targets, whereas left-side targets were detected faster after solving subtraction problems. However, no interaction between space and arithmetic operation was observed in multiplication or division. The implication of these findings is discussed.

  19. Non-perturbative subtractions in the heavy quark effective field theory

    International Nuclear Information System (INIS)

    Maiani, L.; Martinelli, G.; Sachrajda, C.T.

    1992-01-01

    We demonstrate the presence of ultraviolet power divergences in the O(1/m h ) corrections to matrix elements of hadronic operators containing a heavy quark field (where m h is the mass of the heavy quark). These power divergences must be subtracted non-perturbatively. The implications for lattice computations are discussed in detail. (orig.)

  20. Digital subtraction angiography and intraarterial contrast medium injection for coronary examinations

    Energy Technology Data Exchange (ETDEWEB)

    Tobio, R; Kallmeyer, C; Castello, J

    1985-01-01

    Digital subtraction angiography (DSA) is an established method of vasography, most extensively used as i.v. DSA. Intraarterial injection, however, applying selective or non-selective contrast medium injection, seems to be at least as important a technique although it has not yet met with corresponding interest. The article explains advantages of the technique for angiographic examinations, in particular of coronary angiography.

  1. Digital subtraction angiography - a new approach to brain death determination in the newborn

    International Nuclear Information System (INIS)

    Albertini, A.; Schonfeld, S.; Hiatt, M.; Hegyi, T.

    1993-01-01

    The diagnosis of brain death in the newborn infants is elusive and often difficult. The lack of cerebral blood flow has become an identified criterion for loss of cerebral function. The diagnosis can be obtained by the technique of digital subtraction angiography, which is presented in two case reports demonstrating the utility of this technique. (orig.)

  2. Heritage Language Learners in Mixed Spanish Classes: Subtractive Practices and Perceptions of High School Spanish Teachers

    Science.gov (United States)

    Randolph, Linwood J., Jr.

    2017-01-01

    This qualitative study investigated the language ideologies and instructional practices of an entire Spanish language faculty at a high school in a new gateway state for immigration. The study examined additive and subtractive practices of teachers as they strived to teach Spanish to heritage language learners (HLLs) enrolled in mixed…

  3. Does one see gluon condensation after subtraction of mean field perturbation theory from Monte Carlo data

    International Nuclear Information System (INIS)

    Schlichting, H.

    1985-01-01

    We do a linearised mean field calculation in axial gauge for the four dimensional mixed fundamental adjoint SU(2) lattice gauge theory and extract the gluon condensate parameter from the expectation values of the plaquette and the action by subtracting mean field perturbation theory from Monte Carlo data. (orig.)

  4. Low-cost addition-subtraction sequences for the final exponentiation computation in pairings

    DEFF Research Database (Denmark)

    Guzmán-Trampe, Juan E; Cruz-Cortéz, Nareli; Dominguez Perez, Luis

    2014-01-01

    In this paper, we address the problem of finding low cost addition–subtraction sequences for situations where a doubling step is significantly cheaper than a non-doubling one. One application of this setting appears in the computation of the final exponentiation step of the reduced Tate pairing d...

  5. Infrared Thermography Approach for Effective Shielding Area of Field Smoke Based on Background Subtraction and Transmittance Interpolation.

    Science.gov (United States)

    Tang, Runze; Zhang, Tonglai; Chen, Yongpeng; Liang, Hao; Li, Bingyang; Zhou, Zunning

    2018-05-06

    Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR) range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

  6. Infrared Thermography Approach for Effective Shielding Area of Field Smoke Based on Background Subtraction and Transmittance Interpolation

    Directory of Open Access Journals (Sweden)

    Runze Tang

    2018-05-01

    Full Text Available Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

  7. Comparison of digital subtraction angiography with gadolinium-enhanced magnetic resonance angiography in the diagnosis of renal artery stenosis

    International Nuclear Information System (INIS)

    Thornton, J.; O'Callaghan, J.; Varghese, J.C.; Lee, M.J.; Walshe, J.; O'Brien, E.

    1999-01-01

    Renal artery stenosis (RAS) is a treatable cause of hypertension and renal failure for which no ideal screening technique is currently available. We evaluated the use of dynamic gadolinium-enhanced magnetic resonance angiography (MRA) for the diagnosis of RAS. Sixty-two patients with secondary hypertension were enrolled in the study. All patients had conventional renal angiography and gadolinium enhanced MRA. The sequence used was a 3D FMP SPGR sequence with the following parameters (TR: 26 ms, TE: 6.9 ms, flip angle 40 , field of view 36 x 36 cm, matrix 246 x 256, 1 excitation). Gadolinium 0.3 mmol/kg was administered and 60 1.5-mm-thick partitions were obtained over a duration of 3.5 min. The MRA images were then compared with conventional digital subtraction angiography (DSA) images. Conventional DSA demonstrated 138 renal arteries, whereas gadolinium-enhanced MRA demonstrated 129 (93 %). Twenty-one renal artery stenoses and four occluded arteries were seen at conventional DSA. Gadolinium-enhanced MRA had a sensitivity of 88 %, specificity of 98 %, accuracy of 96 %, positive predictive value of 92 % and negative predictive value of 97 % when compared with conventional DSA. Gadolinium-enhanced MRA is an accurate technique for identifying patients with RAS. It is less sensitive in picking up accessory renal arteries. (orig.)

  8. Correlation Between Contrast Time-Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study.

    Science.gov (United States)

    Brunozzi, Denise; Shakur, Sophia F; Ismail, Rahim; Linninger, Andreas; Hsu, Chih-Yang; Charbel, Fady T; Alaraj, Ali

    2018-02-01

    Digital subtraction angiography (DSA) provides an excellent anatomic characterization of cerebral vasculature, but hemodynamic assessment is often qualitative and subjective. Various clinical algorithms have been produced to semiquantify flow from the data obtained from DSA, but few have tested them against reliable flow values. An arched flow model was created and injected with contrast material. Seventeen injections were acquired in anterior-posterior and lateral DSA projections, and 4 injections were acquired in oblique projection. Image intensity change over the angiogram cycle of each DSA run was analyzed through a custom MATLAB code. Time-density plots obtained were divided into 3 components (time-density times, TDTs): TDT 10%-100% (time needed for contrast material to change image intensity from 10% to 100%), TDT 100%-10% (time needed for contrast material to change image intensity from 100% to 10%), and TDT 25%-25% (time needed for contrast material to change from 25% image intensity to 25%). Time-density index (TDI) was defined as model cross-sectional area to TDT ratio, and it was measured against different flow rates. TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% all correlated significantly with flow (P < 0.001). TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% showed, respectively, a correlation coefficient of 0.91, 0.91, and 0.97 in the anterior-posterior DSA projections (P < 0.001). In the lateral DSA projection, TDI 100%-10% showed a weaker correlation (r = 0.57; P = 0.03). Also in the oblique DSA projection, TDIs correlated significantly with flow. TDI on DSA correlates significantly with flow. Although in vitro studies might overlook conditions that occur in patients, this method appears to correlate with the flow and could offer a semiquantitative method to evaluate the cerebral blood flow. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Blood Pool Contrast-enhanced Magnetic Resonance Angiography with Correlation to Digital Subtraction Angiography: A Pictorial Review

    Directory of Open Access Journals (Sweden)

    Martha-Grace Knuttinen

    2014-01-01

    Full Text Available Magnetic resonance angiography (MRA provides noninvasive visualization of the vascular supply of soft tissue masses and vascular pathology, without harmful radiation. This is important for planning an endovascular intervention, and helps to evaluate the efficiency and effectiveness of the treatment. MRA with conventional extracellular contrast agents relies on accurate contrast bolus timing, limiting the imaging window to first-pass arterial phase. The recently introduced blood pool contrast agent (BPCA, gadofosveset trisodium, reversibly binds to human serum albumin, resulting in increased T1 relaxivity and prolonged intravascular retention time, permitting both first-pass and steady-state phase high-resolution imaging. In our practice, high-quality MRA serves as a detailed "roadmap" for the needed endovascular intervention. Cases of aortoiliac occlusive disease, inferior vena cava thrombus, pelvic congestion syndrome, and lower extremity arteriovenous malformation are discussed in this article. MRA was acquired at 1.5 T with an 8-channel phased array coil after intravenous administration of gadofosveset (0.03 mmol/kg body weight, at the first-pass phase. In the steady-state, serial T1-weighted 3D spoiled gradient echo images were obtained with high resolution. All patients underwent digital subtraction angiography (DSA and endovascular treatment. MRA and DSA findings of vascular anatomy and pathology are discussed and correlated. BPCA-enhanced MRA provides high-quality first-pass and steady-state vascular imaging. This could increase the diagnostic accuracy and create a detailed map for pre-intervention planning. Understanding the pharmacokinetics of BPCA and being familiar with the indications and technique of MRA are important for diagnosis and endovascular intervention.

  10. Imaging of the peripheral vascular system

    International Nuclear Information System (INIS)

    Gould, S.A.; Pond, G.D.; Pinsky, S.; Moss, G.S.; Srikantaswamy, S.; Ryo, U.Y.

    1984-01-01

    This book is limited neither to the peripheral vascular system nor to diagnostic imaging techniques. Its 18 chapters cover nonimaging blood-flow techniques (Doppler ultrasound, plethysmography) as well as noninvasive and invasive imaging techniques (ultrasound, computed tomography, radionuclide digital-subtraction angiography, and contrast angiography). These are applied not only to the peripheral vascular system but also to the aorta and vena cava

  11. Third Harmonic Imaging using a Pulse Inversion

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Du, Yigang; Jensen, Jørgen Arendt

    2011-01-01

    The pulse inversion (PI) technique can be utilized to separate and enhance harmonic components of a waveform for tissue harmonic imaging. While most ultrasound systems can perform pulse inversion, only few image the 3rd harmonic component. PI pulse subtraction can isolate and enhance the 3rd...

  12. Follow-up after embolization of ruptured intracranial aneurysms: a prospective comparison of two-dimensional digital subtraction angiography, three-dimensional digital subtraction angiography, and time-of-flight magnetic resonance angiography.

    Science.gov (United States)

    Serafin, Zbigniew; Strześniewski, Piotr; Lasek, Władysław; Beuth, Wojciech

    2012-11-01

    To prospectively compare of the diagnostic value of digital subtraction angiography (DSA) and time-of-flight magnetic resonance angiography (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular treatment. Seventy-two consecutive patients were examined 3 months after the embolization. The index tests included: two-dimensional DSA (2D-DSA), three-dimensional DSA (3D-DSA), and TOF-MRA. The reference test was a retrospective consensus between 2D-DSA images, 3D-DSA images, and source rotational DSA images. The evaluation included: detection of the residual flow, quantification of the flow, and validity of the decision regarding retreatment. Intraobserver agreement and interobserver agreement were determined. The sensitivity and specificity of residual flow detection ranged from 84.6 % (2D-DSA and TOF-MRA) to 92.3 % (3D-DSA) and from 91.3 % (TOF-MRA) to 97.8 % (3D-DSA), respectively. The accuracy of occlusion degree evaluation ranged from 0.78 (2D-DSA) to 0.92 (3D-DSA, Cohen's kappa). The 2D-DSA method presented lower performance in the decision on retreatment than 3D-DSA (P < 0.05, ROC analysis). The intraobserver agreement was very good for all techniques (κ = 0.80-0.97). The interobserver agreement was moderate for TOF-MRA and very good for 2D-DSA and 3D-DSA (κ = 0.72-0.94). Considering the invasiveness of DSA and the minor difference in the diagnostic performance between 3D-DSA and TOF-MRA, the latter method should be the first-line modality for follow-up after aneurysm embolization.

  13. Follow-up after embolization of ruptured intracranial aneurysms: A prospective comparison of two-dimensional digital subtraction angiography, three-dimensional digital subtraction angiography, and time-of-flight magnetic resonance angiography

    International Nuclear Information System (INIS)

    Serafin, Zbigniew; Strzesniewski, Piotr; Lasek, Wladyslaw; Beuth, Wojciech

    2012-01-01

    To prospectively compare of the diagnostic value of digital subtraction angiography (DSA) and time-of-flight magnetic resonance angiography (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular treatment. Seventy-two consecutive patients were examined 3 months after the embolization. The index tests included: two-dimensional DSA (2D-DSA), three-dimensional DSA (3D-DSA), and TOF-MRA. The reference test was a retrospective consensus between 2D-DSA images, 3D-DSA images, and source rotational DSA images. The evaluation included: detection of the residual flow, quantification of the flow, and validity of the decision regarding retreatment. Intraobserver agreement and interobserver agreement were determined. The sensitivity and specificity of residual flow detection ranged from 84.6 % (2D-DSA and TOF-MRA) to 92.3 % (3D-DSA) and from 91.3 % (TOF-MRA) to 97.8 % (3D-DSA), respectively. The accuracy of occlusion degree evaluation ranged from 0.78 (2D-DSA) to 0.92 (3D-DSA, Cohen's kappa). The 2D-DSA method presented lower performance in the decision on retreatment than 3D-DSA (P < 0.05, ROC analysis). The intraobserver agreement was very good for all techniques (κ = 0.80-0.97). The interobserver agreement was moderate for TOF-MRA and very good for 2D-DSA and 3D-DSA (κ = 0.72-0.94). Considering the invasiveness of DSA and the minor difference in the diagnostic performance between 3D-DSA and TOF-MRA, the latter method should be the first-line modality for follow-up after aneurysm embolization. (orig.)

  14. Follow-up after embolization of ruptured intracranial aneurysms: A prospective comparison of two-dimensional digital subtraction angiography, three-dimensional digital subtraction angiography, and time-of-flight magnetic resonance angiography

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    Serafin, Zbigniew; Strzesniewski, Piotr; Lasek, Wladys