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Sample records for ak multidetector computed

  1. Cardiac Computed Tomography (Multidetector CT, or MDCT)

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Cardiac Computed Tomography (Multidetector CT, or MDCT) Updated:Sep 3,2015 ... facts MDCT is a very fast type of computed tomography (CT) scan. MDCT creates pictures of the healthy ...

  2. [Valvular heart disease: multidetector computed tomography evaluation].

    PubMed

    Franco, A; Fernández-Pérez, G C; Tomás-Mallebrera, M; Badillo-Portugal, S; Orejas, M

    2014-01-01

    Heart valve disease is a clinical problem that has been studied with classical imaging techniques like echocardiography and MRI. Technological advances in CT make it possible to obtain static and dynamic images that enable not only a morphological but also a functional analysis in many cases. Although it is currently indicated only in patients with inconclusive findings at echocardiography and MRI or those in whom these techniques are contraindicated, multidetector CT makes it possible to diagnose stenosis or regurgitation through planimetry, to evaluate and quantify valvular calcium, and to show the functional repercussions of these phenomena on the rest of the structures of the heart. Given that multidetector CT is being increasingly used in the diagnosis of ischemic heart disease, we think it is interesting for radiologists to know its potential for the study of valvular disease. PMID:23246401

  3. Multidetector computed tomographic angiography of the cardiovascular system

    PubMed Central

    Burrill, Joshua; Dabbagh, Zaid; Gollub, Frank; Hamady, Mohamed

    2007-01-01

    The introduction of multidetector computed tomography (MDCT) is considered a dramatic development in CT imaging that has direct implication in the imaging of various systems, in particular the cardiovascular system. The advantages of MDCT are an enormous increase in imaging acquisition speed, more coverage of the patient, and high spatial resolution. This article reviews the recent developments in CT angiography and discusses the clinical application relevant to diagnosis and endovascular treatment of cardiovascular diseases. PMID:17989269

  4. Multidetector Computer Tomography: Evaluation of Blunt Chest Trauma in Adults

    PubMed Central

    Matos, António P.; Mascarenhas, Vasco; Herédia, Vasco

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall. PMID:25295188

  5. Multidetector computer tomography: evaluation of blunt chest trauma in adults.

    PubMed

    Palas, João; Matos, António P; Mascarenhas, Vasco; Herédia, Vasco; Ramalho, Miguel

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall. PMID:25295188

  6. Multidetector computed tomography of temporomandibular joint: A road less travelled

    PubMed Central

    Pahwa, Shivani; Bhalla, Ashu Seith; Roychaudhary, Ajoy; Bhutia, Ongkila

    2015-01-01

    This article reviews the imaging anatomy of temporomandibular joint (TMJ), describes the technique of multi-detector computed tomography (MDCT) of the TMJ, and describes in detail various osseous pathologic afflictions affecting the joint. Traumatic injuries affecting the mandibular condyle are most common, followed by joint ankylosis as a sequel to arthritis. The congenital anomalies are less frequent, hemifacial microsomia being the most commonly encountered anomaly involving the TMJ. Neoplastic afflictions of TMJ are distinctly uncommon, osteochondroma being one of the most common lesions. MDCT enables comprehensive evaluation of osseous afflictions of TMJ, and is a valuable tool for surgical planning. Sagittal, coronal and 3D reformatted images well depict osseous TMJ lesions, and their relationship to adjacent structures. PMID:25984518

  7. Multidetector computed tomography findings in deaths with severe burns.

    PubMed

    Levy, Angela D; Harcke, Howard T; Getz, John M; Mallak, Craig T

    2009-06-01

    This study compared autopsy with postmortem multidetector computed tomography (MDCT) findings in charred remains. Seventeen consecutive male subjects (mean age, 29.4 years) who perished in a fire-related event resulting in charred remains underwent total body MDCT immediately prior to routine autopsy that included serum carboxyhemoglobin measurement. MDCT showed all thermal tissue changes (skin and subcutaneous fat loss, skeletal muscle retraction, pugilistic attitude, cortical fractures, bone and organ destruction, thermal epidural hematoma, and thermal amputation) and established all fracture patterns that were lethal, but autopsy added the fire as a contributory cause of death when there was carboxyhemoglobin elevation. MDCT had limited value in determination of lethal vascular and visceral injuries. MDCT is an effective complement to autopsy in the setting of charred remains and may serve to augment a limited autopsy. This may be particularly useful in mass casualty scenarios. PMID:19465802

  8. Cardiac Injuries: A Review of Multidetector Computed Tomography Findings

    PubMed Central

    Baxi, Ameya Jagdish; Restrepo, Carlos; Mumbower, Amy; McCarthy, Michael; Rashmi, Katre

    2015-01-01

    Trauma is the leading cause of death in United States in the younger population. Cardiac trauma is common following blunt chest injuries and is associated with high morbidity and mortality. This study discusses various multidetector computed tomography (MDCT) findings of cardiac trauma. Cardiac injuries are broadly categorized into the most commonly occurring blunt cardiac injury and the less commonly occurring penetrating injury. Signs and symptoms of cardiac injury can be masked by the associated injuries. Each imaging modality including chest radiographs, echocardiography, magnetic resonance imaging and MDCT has role in evaluating these patients. However, MDCT is noninvasive; universally available and has a high spatial, contrast, and temporal resolution. It is a one stop shop to diagnose and evaluate complications of cardiac injury. MDCT is an imaging modality of choice to evaluate patients with cardiac injuries especially the injuries capable of causing hemodynamic instability. PMID:26839855

  9. Detection of plaque rupture using 64-slice multidetector row computed tomography

    PubMed Central

    Reimann, Anja J; Beck, Torsten; Heuschmid, Martin; Brodoefel, Harald; Burgstahler, Christof; Schröder, Stephen; Kopp, Andreas F

    2008-01-01

    The present case report describes a 37-year-old man who presented to the emergency room with symptoms of a myocardial infarction but no high-grade stenosis on conventional catheter angiography. Consecutive multi-detector row computed tomography of the coronary arteries showed an intimal flap along a fibrous plaque formation in the left anterior descending artery. This finding was found to represent a plaque rupture, and the lesion was treated with an 18 mm stent. Multidetector row computed tomography helped to correctly position the stent by identifying the exact location of the rupture along the long plaque formation. PMID:18340394

  10. Multi-Detector Computed Tomography Angiography for Coronary Artery Disease

    PubMed Central

    2005-01-01

    Executive Summary Purpose Computed tomography (CT) scanning continues to be an important modality for the diagnosis of injury and disease, most notably for indications of the head and abdomen. (1) According to a recent report published by the Canadian Institutes of Health Information, (1) there were about 10.3 scanners per million people in Canada as of January 2004. Ontario had the fewest number of CT scanners per million compared to the other provinces (8 CT scanners per million). The wait time for CT in Ontario of 5 weeks approaches the Canadian median of 6 weeks. This health technology and policy appraisal systematically reviews the published literature on multidetector CT (MDCT) angiography as a diagnostic tool for the newest indication for CT, coronary artery disease (CAD), and will apply the results of the review to current health care practices in Ontario. This review does not evaluate MDCT to detect coronary calcification without contrast medium for CAD screening purposes. The Technology Compared with conventional CT scanning, MDCT can provide smaller pieces of information and can cover a larger area faster. (2) Advancing MDCT technology (8, 16, 32, 64 slice systems) is capable of producing more images in less time. For general CT scanning, this faster capability can reduce the time that patients must stay still during the procedure, thereby reducing potential movement artefact. However, the additional clinical utility of images obtained from faster scanners compared to the images obtained from conventional CT scanners for current CT indications (i.e., non-moving body parts) is not known. There are suggestions that the new fast scanners can reduce wait times for general CT. MDCT angiography that utilizes a contrast medium, has been proposed as a minimally invasive replacement to coronary angiography to detect coronary artery disease. MDCT may take between 15 to 45 minutes; coronary angiography may take up to 1 hour. Although 16-slice and 32-slice CT

  11. Multidetector computed tomography evaluation of cavernous haemangioma of the azygous vein

    PubMed Central

    Das, Karuna Moy; Ahmed, Ali M.; Aljubab, Abdulwahab; Alzoum, Mohammed A.

    2013-01-01

    Giant cavernous haemangioma of azygous arch is extremely rare. We present the multidetector computed tomography (MDCT) features of a mediastinal cavernous haemangioma in an asymptomatic child detected in a follow-up examination. MDCT features with multiple venous lakes filling from the periphery, focal specks of calcification, low-density soft tissue mass along with tortuous varicose veins and large feeding veins from the abdomen are suggestive of cavernous haemangioma. PMID:23660735

  12. Multi-detector row computed tomography angiography of peripheral arterial disease

    PubMed Central

    Dijkshoorn, Marcel L.; Pattynama, Peter M. T.; Myriam Hunink, M. G.

    2007-01-01

    With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD. PMID:17882427

  13. Bosniak classification of renal cystic lesions according to multidetector computed tomography findings*

    PubMed Central

    de Miranda, Christiana Maia Nobre Rocha; Maranhão, Carol Pontes de Miranda; dos Santos, Carla Jotta Justo; Padilha, Igor Gomes; de Farias, Lucas de Pádua Gomes; da Rocha, Milzi Sarmento

    2014-01-01

    Renal cystic lesions are usually diagnosed in the radiologists’ practice and therefore their characterization is crucial to determine the clinical approach to be adopted and prognosis. The Bosniak classification based on computed tomography findings has allowed for standardization and categorization of lesions in increasing order of malignancy (I, II, IIF, III and IV) in a simple and accurate way. The present iconographic essay developed with multidetector computed tomography images of selected cases from the archives of the authors’ institution, is aimed at describing imaging findings that can help in the diagnosis of renal cysts. PMID:25741060

  14. Evaluation of pulmonary sequestration with multidetector computed tomography angiography in a select cohort of patients: A retrospective study

    PubMed Central

    Long, Qihua; Zha, Yunfei; Yang, Zhigang

    2016-01-01

    OBJECTIVES: This study aimed to evaluate the role of multidetector computed tomography angiography in diagnosing patients with pulmonary sequestration. METHODS: We retrospectively analyzed the computed tomography studies and clinical materials of 43 patients who had undergone preoperative multidetector computed tomography angiography in our hospital and had pathologically proven pulmonary sequestration. Each examination of pulmonary sequestration was reviewed for type, location, parenchymal changes, arterial supply and venous drainage on two-dimensional and three-dimensional computed tomography images. RESULTS: Multidetector computed tomography successfully detected all pulmonary sequestrations in the 43 patients (100%). This included 40 patients (93.0%) with intralobar sequestration and 3 patients (7.0%) with extralobar sequestration. The locations of pulmonary sequestration were left lower lobe (28 cases, 70% of intralobar sequestrations), right lower lobe (12 cases, 30% of intralobar sequestrations) and costodiaphragmatic sulcus (3 cases). Cases of sequestered lung presented as mass lesions (37.2%), cystic lesions (32.6%), pneumonic lesions (16.3%), cavitary lesions (9.3%) and bronchiectasis (4.6%). The angioarchitecture of pulmonary sequestration, including feeding arteries from the thoracic aorta (86.1%), celiac truck (9.3%), abdominal aorta (2.3%) and left gastric artery (2.3%) and venous drainage into inferior pulmonary veins (86.0%) and the azygos vein system (14.0%), was visualized on multidetector computed tomography. Finally, the multidetector computed tomography angiography results of the sequestered lungs and angioarchitectures were surgically confirmed in all the patients. CONCLUSIONS: As a noninvasive modality, multidetector computed tomography angiography is helpful for making diagnostic decisions regarding pulmonary sequestration with high confidence and for visualizing the related parenchymal characteristics, arterial supply, and venous drainage

  15. Role of Multidetector Computed Tomography in the Diagnosis of Colorectal Perforations.

    PubMed

    Saturnino, Pietro Paolo; Pinto, Antonio; Liguori, Carlo; Ponticiello, Gianluca; Romano, Luigia

    2016-02-01

    Colonic perforations can be classified into perforations that occur at the site of a localized pathologic process and cecal perforations that occur secondary to distal colonic obstructions. Rectal perforations may result from foreign bodies inserted into the rectum; moreover, deep rectal biopsies, polypectomy, improper cleansing enema, or thermometer placement may also lead to rectal perforation. Correct identification of the cause and site of the perforation is crucial for appropriate management and surgical planning. Multidetector row computed tomography has a pivot role in planning the type of operative treatment, the prognosis, and in assessing those patients who have clinical symptoms of peritonitis but no radiographic signs of perforation. PMID:26827738

  16. Tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography: association with N categories

    PubMed Central

    Li, Hang; Chen, Xiao-li; Li, Jun-ru; Li, Zhen-lin; Chen, Tian-wu; Pu, Hong; Yin, Long-lin; Xu, Guo-hui; Li, Zhen-wen; Reng, Jing; Zhou, Peng; Cheng, Zhu-zhong; Cao, Ying

    2016-01-01

    OBJECTIVE: To determine whether the gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict the presence of regional lymph node metastasis and could determine N categories. MATERIALS AND METHODS: A total of 202 consecutive patients with gastric adenocarcinoma who had undergone gastrectomy 1 week after contrast-enhanced multidetector computed tomography were retrospectively identified. The gross tumor volume was evaluated on multidetector computed tomography images. Univariate and multivariate analyses were performed to determine whether the gross tumor volume could predict regional lymph node metastasis, and the Mann-Whitney U test was performed to compare the gross tumor volume among N categories. Additionally, a receiver operating characteristic analysis was performed to identify the accuracy of the gross tumor volume in differentiating N categories. RESULTS: The gross tumor volume could predict regional lymph node metastasis (p<0.0001) in the univariate analysis, and the multivariate analyses indicated that the gross tumor volume was an independent risk factor for regional lymph node metastasis (p=0.005, odds ratio=1.364). The Mann-Whitney U test showed that the gross tumor volume could distinguish N0 from the N1-N3 categories, N0-N1 from N2-N3, and N0-N2 from N3 (all p<0.0001). In the T1-T4a categories, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 12.3 cm3), N0-N1 from N2-N3 (cutoff, 16.6 cm3), and N0-N2 from N3 (cutoff, 24.6 cm3). In the T4a category, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 15.8 cm3), N0-N1 from N2-N3 (cutoff, 17.8 cm3), and N0-N2 from N3 (cutoff, 24 cm3). CONCLUSION: The gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict regional lymph node metastasis and N categories. PMID:27166769

  17. Congenital pulmonary venolobar syndrome: Value of multidetector computed tomography in preoperative assessment

    PubMed Central

    Hamad, Abdel-Mohsen Mahmoud

    2012-01-01

    A 6-month old baby referred to our department because of recurrent attacks of respiratory distress with chest infection. Chest radiology revealed reduction of the right hemithorax with mediastinal shift to the right. Multidetector computed tomography showed hypoplasia of the right lung and right pulmonary artery, systemic arterial supply to the lung from the abdominal aorta, and and absence of right venous drainage to the left atrium. This picture is consistent with congenital pulmonary venolobar syndrome. The patient underwent right pneumonectomy; the postoperative course was uneventful. PMID:22924077

  18. Multidetector computed tomography imaging of congenital anomalies of major airways: A pictorial essay.

    PubMed

    Sundarakumar, Dinesh Kumar; Bhalla, Ashu Seith; Sharma, Raju; Gupta, Arun Kumar; Kabra, Susheel Kumar; Jagia, Priya

    2011-12-28

    Congenital airway anomalies can be asymptomatic or may cause severe respiratory distress requiring immediate treatment. These anomalies can present early in life, or may be just incidental findings. It is important to recognize these entities to realize their clinical significance and to avoid false diagnosis. In this article, the various congenital airway anomalies and their imaging features by multidetector computed tomography (MDCT) are reviewed in order of occurrence during the embryological timeline. This pictorial essay reviews the various distinct congenital airway lesions and their MDCT manifestations. It also provides insight into the embryological basis of the congenital airway lesions encountered. PMID:22224177

  19. Multi-detector computed tomography imaging of large airway pathology: A pictorial review

    PubMed Central

    Jugpal, Tejeshwar Singh; Garg, Anju; Sethi, Gulshan Rai; Daga, Mradul Kumar; Kumar, Jyoti

    2015-01-01

    The tracheobronchial tree is a musculo-cartilagenous framework which acts as a conduit to aerate the lungs and consequently the entire body. A large spectrum of pathological conditions can involve the trachea and bronchial airways. These may be congenital anomalies, infections, post-intubation airway injuries, foreign body aspiration or neoplasms involving the airway. Appropriate management of airway disease requires an early and accurate diagnosis. In this pictorial essay review, we will comprehensively describe the various airway pathologies and their imaging findings by multi-detector computed tomography. PMID:26753061

  20. Sex estimation from sternal measurements using multidetector computed tomography.

    PubMed

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Bilgili, Mustafa Gokhan; Solmaz, Dilek; Erdil, Irem; Can, Ismail Ozgur

    2014-12-01

    We aimed to show the utility and reliability of sternal morphometric analysis for sex estimation.Sex estimation is a very important step in forensic identification. Skeletal surveys are main methods for sex estimation studies. Morphometric analysis of sternum may provide high accuracy rated data in sex discrimination. In this study, morphometric analysis of sternum was evaluated in 1 mm chest computed tomography scans for sex estimation. Four hundred forty 3 subjects (202 female, 241 male, mean age: 44 ± 8.1 [distribution: 30-60 year old]) were included the study. Manubrium length (ML), mesosternum length (2L), Sternebra 1 (S1W), and Sternebra 3 (S3W) width were measured and also sternal index (SI) was calculated. Differences between genders were evaluated by student t-test. Predictive factors of sex were determined by discrimination analysis and receiver operating characteristic (ROC) analysis. Male sternal measurement values are significantly higher than females (P < 0.001) while SI is significantly low in males (P < 0.001). In discrimination analysis, MSL has high accuracy rate with 80.2% in females and 80.9% in males. MSL also has the best sensitivity (75.9%) and specificity (87.6%) values. Accuracy rates were above 80% in 3 stepwise discrimination analysis for both sexes. Stepwise 1 (ML, MSL, S1W, S3W) has the highest accuracy rate in stepwise discrimination analysis with 86.1% in females and 83.8% in males. Our study showed that morphometric computed tomography analysis of sternum might provide important information for sex estimation. PMID:25501090

  1. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations*

    PubMed Central

    de Mello Júnior, Carlos Fernando; Araujo Neto, Severino Aires; de Carvalho Junior, Arlindo Monteiro; Rebouças, Rafael Batista; Negromonte, Gustavo Ramalho Pessoa; de Oliveira, Carollyne Dantas

    2016-01-01

    Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations.

  2. Comparison between clinical indicators of transmembrane oxygenator thrombosis and multidetector computed tomographic analysis.

    PubMed

    Panigada, Mauro; L'Acqua, Camilla; Passamonti, Serena Maria; Mietto, Cristina; Protti, Alessandro; Riva, Roberto; Gattinoni, Luciano

    2015-04-01

    This study aims to assess whether multidetector computed tomography (MDCT) could accurately confirm the clinical suspicion of transmembrane oxygenator thrombosis (MOT) during extracorporeal membrane oxygenation (ECMO). Twenty-seven oxygenators were examined using MDCT at the end of patient treatment. Transmembrane oxygenator thrombosis was suspected in 15 of them according to the presence of at least 2 of the following clinical indicators: (1) increase in d-dimer, (2) decrease in platelet count, (3) decrease in oxygenator performance, and (4) presence of clots on the surface of the oxygenator. Transmembrane oxygenator thrombosis was confirmed by MDCT in 5 (33%) of them. Transmembrane oxygenator thrombosis was unexpectedly found in 5 (41%) of the remaining 12 oxygenators not suspected for MOT. Eight (80%) of these oxygenators had clots accounting for less than 1% of total volume. Clots were mainly detectable at the apical corner of the oxygenator, most likely due to greater blood stasis. We found a significant increase in d-dimer and in membrane oxygenator shunt and a decrease in platelet count from the start to the discontinuation of ECMO. Hemostatic abnormalities significantly reverted 48 hours after oxygenator removal, suggesting the role of ECMO in activation of the coagulation cascade. Multidetector computed tomographic scan could not accurately confirm the clinical suspicion of MOT. PMID:25547046

  3. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations.

    PubMed

    de Mello Júnior, Carlos Fernando; Araujo Neto, Severino Aires; de Carvalho Junior, Arlindo Monteiro; Rebouças, Rafael Batista; Negromonte, Gustavo Ramalho Pessoa; de Oliveira, Carollyne Dantas

    2016-01-01

    Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations. PMID:27403020

  4. An Unusual Left Ventricular Outflow Pseudoaneurysm: Usefulness of Echocardiography and Multidetector Computed Tomography for Surgical Repair

    SciTech Connect

    Da Col, Uberto; Ramoni, Enrico Di Bella, Isidoro; Ragni, Temistocle

    2009-01-15

    Left ventricular outflow tract (LVOT) pseudoaneurysm is a rare but potentially lethal complication, mainly after aortic root endocarditis or surgery. Usually it originates from a dehiscence in the mitral-aortic intervalvular fibrosa and it arises posteriorly to the aortic root. Due to these anatomical features, its imaging assessment is challenging and surgical repair requires complex procedures. An unusual case of LVOT pseudoaneurysm is described. It was detected by transthoracic ecocardiography 7 months after aortic root replacement for acute endocarditis. Multidetector computed tomography (MDCT) confirmed the presence of a pouch located between the aortic root and the right atrium. Computed tomography also detected the origin of the pseudoaneurysm from the muscular interventricular septum of the LVOT, rather below the aortic valve plane. It was repaired with an extracardiac surgical approach, sparing the aortic root bioprosthesis previously implanted. The high-resolution three-dimensional details provided by the preoperative MDCT allowed us to plan a simple and effective surgical strategy.

  5. Multi-detector computed tomography demonstrates smoke inhalation injury at early stage.

    PubMed

    Koljonen, Virve; Maisniemi, Kreu; Virtanen, Kaisa; Koivikko, Mika

    2007-06-01

    A multitrauma victim was transported to our trauma centre. Smoke inhalation injury was suspected based on trauma history and clinical examination. The first trauma computer tomography (CT) obtained 2.8 h after the injury revealed subtle ground-glass opacifications with mainly peribronchial distribution and patchy peribronchial consolidations centrally in the left lung. A repeated scan showed a more distinctive demarcation of the peribronchial opacities, further substantiating the clinically verified smoke inhalation injury. The golden standard for diagnosing smoke inhalation injury still is fibroptic bronchoscopy examination. This paper shows that lesions typical to smoke inhalation injury appear much earlier than previously reported. Whether assessment of smoke inhalation injury severity using CT could clinically benefit patients is controversial and still requires further research. Multi-detector computed tomography is readily available in trauma centres and to simply neglect its potential as a diagnostic tool in some inhalation injury would be unwise. PMID:17285330

  6. Three-dimensional reconstruction of New Zealand rabbit antebrachium by multidetector computed tomography

    PubMed Central

    Özkadif, S; Eken, E; Beşoluk, K; Dayan, M. O.

    2015-01-01

    The aim of this study was to reveal biometric peculiarities of New Zealand white rabbit antebrachium (radius and ulna) by means of three-dimensional (3D) reconstruction of multidetector computed tomography (MDCT) images. Under general anesthesia, the antebrachiums of a total of sixteen rabbits of both sexes were scanned with a general diagnostic MDCT. Biometric measurements of the reconstructed models from high resolution MDCT images were analyzed statistically. Consequently, when biometric measurement values of corresponding bones of antebrachium were compared, it was revealed that there was no statistical significance within both sexes but there were statistically important differences between both sexes in some biometric measurements. It has been suggested that the results from the study can shed light on future studies on the skeletal system and can form a modern point of view to anatomical education. PMID:27175177

  7. [Multidetector computed tomography of coronary arteries: state of the art. Second part: clinical applications].

    PubMed

    González, Aloha Meave; Rosas, Erick Alexánderson; Valero, Mónica Rodríguez; Ramírez, Gabriela Meléndez; García, Alfonso Martínez; Fernández, Carlos Sierra; Torres, Rodrigo Calleja; Castillo, Leonardo García-Rojas; Molina, Pedro Alberto Lamothe; Zarza, Mary Carmen Herrera; de Avila, Martha Armas; López, Juan Manuel Ochoa; Vázquez-Lamadrid, Jorge; Hayama, Eric Kimura

    2008-01-01

    At the beginning of the evaluation of Coronary Artery Disease (CAD), Coronary Multidetector Computed Tomography (MDCT) was exclusively used to detect calcified plaques in coronary arteries through the Calcium Score, whose value by itself is limited. Nowadays, thanks to the technological advancements, potential clinical applications, with this method, include detection of coronary arterial stenosis, assessment of coronary bridges, and evaluation of anomalous coronaries. The intraluminal coronary stent evaluation is not possible yet, but this might become possible with the new-generation scanners. At the moment, the published results seem to be promising, nonetheless, the enthusiasm generated by this method should be accompanied by adequate training, as well as by its validation and certification. PMID:18754411

  8. Congenital coronary arteries anomalies: review of the literature and multidetector computed tomography (MDCT)-appearance.

    PubMed

    Montaudon, M; Latrabe, V; Iriart, X; Caix, P; Laurent, F

    2007-07-01

    The prevalence of coronary arteries congenital anomalies is 1 to 2% in the general population. Although the spectrum of their clinical manifestations is very broad from total inocuity to lethal, anomalies of coronary arteries need to be recognized by clinicians in certain circumstances: they are the first cause of death in young adults under physical exercise and an abnormal course of a coronary artery can complicate a cardiac surgery. Therefore, a non-invasive test is highly suitable for detecting anomalies of coronary arteries and multidetector computed tomography (MDCT) is likely to be the best one. To understand how anomalies of coronary arteries may occur, we have reviewed the recent literature about their development. Then, the main types of anomalies are presented with their clinical context, and representative MDCT images from our personal database are used for illustration. PMID:17563833

  9. Demonstration of normal and dilated testicular veins by multidetector computed tomography.

    PubMed

    Karcaaltincaba, Musturay

    2011-04-01

    Recent advances in multidetector computed tomography (MDCT) technology enabled better visualization of testicular (gonadal) vein using submillimeter slice thickness and three-dimensional images. Normally, the testicular vein measures 1-3 mm and drains into the inferior vena cava and left renal vein on the right and left sides, respectively. They can be seen in most patients during MDCT studies. Curved planar and volume-rendered images can be used to display testicular veins. We aim to demonstrate MDCT findings of normal testicular vein and its pathologies including varicocele, varices, the testicular vascular pedicle sign, and phlebolith. The testicular vein can be dilated owing to varicocele or portal hypertension and in patients with intraabdominal seminomas arising from undescended testis. The testicular vein can also cause ureteral compression at the crossing point. Understanding MDCT findings of the normal testicular vein and its various pathologies can allow a correct diagnosis, thereby avoiding further diagnostic tests. PMID:21519988

  10. [Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms].

    PubMed

    Casula, E; Lonjedo, E; Cerverón, M J; Ruiz, A; Gómez, J

    2014-01-01

    The increase in the frequency of abdominal aortic aneurysms (AAA) and the widely accepted use of endovascular aneurysm repair (EVAR) as a first-line treatment or as an alternative to conventional surgery make it necessary for radiologists to have thorough knowledge of the pre- and post-treatment findings. The high image quality provided by multidetector computed tomography (MDCT) enables CT angiography to play a fundamental role in the study of AAA and in planning treatment. The objective of this article is to review the cases of AAA in which CT angiography was the main imaging technique, so that radiologists will be able to detect the signs related to this disease, to diagnose it, to plan treatment, and to detect complications in the postoperative period. PMID:23489768

  11. Staging of colorectal cancer using contrast-enhanced multidetector computed tomographic colonography

    PubMed Central

    Narayanan, Srikala; Kalra, Naveen; Bhatia, Anmol; Wig, Jaidev; Rana, Surinder; Bhasin, Deepak; Vaiphei, Kim; Khandelwal, Niranjan

    2014-01-01

    INTRODUCTION Preoperative staging is essential for the optimal treatment and surgical planning of colorectal cancers. This study was aimed to evaluate the accuracy of colorectal cancer staging done using contrast-enhanced multidetector computed tomographic colonography (CEMDCTC). METHODS We recruited 25 patients with 28 proven colorectal cancers. A 16-slice multidetector computed tomography scanner was used to generate two-dimensional multiplanar reformatted sagittal, coronal and oblique coronal images, and three-dimensional virtual colonography (endoluminal) images. Axial and reformatted views were analysed, and TNM staging was done. Patients underwent surgery and conventional colonoscopy, and surgical histopathological correlation was obtained. RESULTS The diagnostic accuracies for TNM colorectal cancer staging were 92.3% for T staging, 42.3% for N staging and 96.1% for M staging using CEMDCTC. There was excellent positive correlation for T staging between CEMDCTC and both surgery (κ-value = 0.686) and histopathology (κ-value = 0.838) (p < 0.0001), and moderate positive correlation for N staging between CEMDCTC and surgery (κ-value = 0.424; p < 0.0001). The correlation between CEMDCTC and histopathology for N staging was poor (κ-value = 0.186; p < 0.05); the negative predictive value was 100% for lymph node detection. Moderate positive correlation was seen for M staging between CEMDCTC and both surgery (κ-value = 0.462) and histopathology (κ-value = 0.649). No false negatives were identified in any of the M0 cases. CONCLUSION CEMDCTC correlated well with pathologic T and M stages, but poorly with pathologic N stage. It is an extremely accurate tool for T staging, but cannot reliably distinguish between malignant lymph nodes and enlarged reactive lymph nodes. PMID:25630322

  12. Comparison of the Diagnostic Image Quality of the Canine Maxillary Dentoalveolar Structures Obtained by Cone Beam Computed Tomography and 64-Multidetector Row Computed Tomography.

    PubMed

    Soukup, Jason W; Drees, Randi; Koenig, Lisa J; Snyder, Christopher J; Hetzel, Scott; Miles, Chanda R; Schwarz, Tobias

    2015-01-01

    The objective of this blinded study was to validate the use of cone beam computed tomography (C) for imaging of the canine maxillary dentoalveolar structures by comparing its diagnostic image quality with that of 64-multidetector row CT Sagittal slices of a tooth-bearing segment of the maxilla of a commercially purchased dog skull embedded in methylmethacrylate were obtained along a line parallel with the dental arch using a commercial histology diamond saw. The slice of tooth-bearing bone that best depicted the dentoalveolar structures was chosen and photographed. The maxillary segment was imaged with cone beam CT and 64-multidetector row CT. Four blinded evaluators compared the cone beam CT and 64-multidetector row CT images and image quality was scored as it related to the anatomy of dentoalveolar structures. Trabecular bone, enamel, dentin, pulp cavity, periodontal ligament space, and lamina dura were scored In addition, a score depicting the evaluators overall impression of the image was recorded. Images acquired with cone beam CT were found to be significantly superior in image quality to images acquired with 64-multidetector row CT overall, and in all scored categories. In our study setting cone beam CT was found to be a valid and clinically superior imaging modality for the canine maxillary dentoalveolar structures when compared to 64-multidetector row CT. PMID:26415384

  13. Dose reduction by automatic exposure control in multidetector computed tomography: comparison between measurement and calculation.

    PubMed

    Lechel, U; Becker, C; Langenfeld-Jäger, G; Brix, G

    2009-04-01

    The aim of this study was to investigate the potential of dose reduction in multidetector computed tomography (MDCT) by current-modulated automatic exposure control (AEC) and to test the reliability of the dose estimation by the conventional CT dosimetry program CT-EXPO, when an average tube current is used. Phantom measurements were performed at a CT system with 64 detector rows for four representative examination protocols, each without and with current-modulated AEC. Organ and effective doses were measured by thermoluminescence dosimeters (TLD) at an anthropomorphic Alderson phantom and compared with those given by the calculation with CT-EXPO. The application of AEC yielded dose reductions between 27 and 40% (TLD measurements). While good linearity was observed between measured and computed effective dose values both without and with AEC, the organ doses showed large deviations between measurement and calculation. The dose to patients undergoing a MDCT examination can be reduced considerably by applying a current-modulated AEC. Dosimetric algorithms using a constant current-time product provide reliable estimates of the effective dose. PMID:18987864

  14. Multidetector computed tomography findings and correlations with proteinuria in nutcracker syndrome.

    PubMed

    Cho, Byoung Soo; Suh, Jin Soon; Hahn, Won Ho; Kim, Sung Do; Lim, Joo Won

    2010-03-01

    We evaluated the effectiveness of multidetector computed tomography (MDCT) as a diagnostic tool for nutcracker syndrome (NS) and its association with proteinuria. The angle and distance between the aorta and the superior mesenteric artery (SMA), the degree of difference in corticomedullary enhancement (DCE) between kidneys in the nephrographic phase of computed tomography, peak velocity ratio (PVR), and anteroposterior diameter ratio (APDR) in the sonogram were measured. The MDCT results, sonogram results, and the ratio of protein:creatinine were significantly different between NS patients and the controls. The area under the curve for angle, distance, and DCE were 0.895 +/- 0.058, 0.876 +/- 0.063, and 0.942 +/- 0.036, respectively. The cutoff values for angle and distance had sensitivity and specificity values of 96.2 and 80% for <22.4 degrees and 84.6 and 80% for <4.9 mm, respectively. The DCE had a sensitivity of 88.5% and a specificity of 100% for the positive scores. There were significant correlations between the degree of DCE and the ratio of protein:creatinine (r = 0.337, p = 0.031), and between distance and the ratio of protein:creatinine (r = -0.419, p = 0.006). We conclude that MDCT has diagnostic value for NS in children and that MDCT findings are correlated with proteinuria. PMID:20020159

  15. Multidetector computed tomography analysis of benign and malignant nodules in patients with chronic lymphocytic thyroiditis

    PubMed Central

    ZHU, CAISONG; LIU, WEI; YANG, JUN; YANG, JING; SHAO, KANGWEI; YUAN, LIXIN; CHEN, HAIRONG; LU, WEI; ZHU, YING

    2016-01-01

    The aim of the present study was to compare the multidetector computed tomography (MDCT) features of benign and malignant nodules in patients with chronic lymphocytic thyroiditis (CLT). MDCT findings, including the size, solid percentage, calcification, margin, capsule, anteroposterior-transverse diameter ratio as well as the mode and the degree of enhancement of 137 thyroid nodules in 127 CLT cases were retrospectively analyzed. Furthermore, the correlation between MDCT findings and pathological results combined with the CT perfusion imaging was analyzed for the differences between benign and malignant nodules. A total of 77.5% (31/40) of malignant nodules were completely solid, and 33% (32/97) of benign nodules were predominantly cystic. Compared with the benign nodules, micro-calcification and internal calcification were more frequently observed in the malignant nodules (P<0.05). MDCT features such as ill-defined margin, absence of capsule or incomplete capsule or homogeneous enhancement were more likely to be present in the malignant nodules (P<0.05). Nevertheless, no significant difference was observed in the enhancement degree at arterial or venous phase between benign and malignant nodules (P>0.05). MDCT features are useful in differentiating the benign and malignant nodules in CLT patients, and it may be essential for a radiologist to review the MDCT characteristics of nodules in the clinical practice. PMID:27347131

  16. Complete Preoperative Evaluation of Pulmonary Atresia with Ventricular Septal Defect with Multi-Detector Computed Tomography

    PubMed Central

    Liu, Jingzhe; Li, Hongyin; Liu, Zhibo; Wu, Qingyu; Xu, Yufeng

    2016-01-01

    Objective To compare multi-detector computed tomography (MDCT) with cardiac catheterization and transthoracic echocardiography (TTE) in comprehensive evaluation of the global cardiovascular anatomy in patients with pulmonary atresia with ventricular septal defect (PA-VSD). Methods The clinical and imaging data of 116 patients with PA-VSD confirmed by surgery were reviewed. Using findings at surgery as the reference standard, data from MDCT, TTE and catheterization were reviewed for assessment of native pulmonary vasculature and intracardiac defects. Results MDCT was more accurate than catheterization and TTE in identification of native pulmonary arteries. MDCT is also the most accurate test for delineation of the major aortopulmonary collateral arteries. The inter-modality agreement for evaluation of overriding aorta and VSD were both excellent. In the subgroup with surgical correlation, excellent agreement was found between TTE and surgery, and substantial agreement was also found at MDCT. Conclusion MDCT can correctly delineate the native pulmonary vasculatures and intracardiac defects and may be a reliable method for noninvasive assessment of global cardiovascular abnormalities in patients with PA-VSD. PMID:26741649

  17. Evaluation of hepatic arterial anatomy by multidetector computed tomographic angiography in living donor liver transplantation.

    PubMed

    Keles, Papatya; Yuce, Ihsan; Keles, Sait; Kantarci, Mecit

    2016-06-01

    The aim of this study was to define the different courses and percentages of hepatic artery that were detected during preoperative evaluation of living liver donors by multidetector computed tomographic angiography (MDCTA). We evaluated 150 donors before hepatic transplantation. All of the donors were evaluated by multislice CT scan with 256 detectors. For each patient, arterial, portal and venous phase images were obtained. The hepatic arterial variations were evaluated by the same radiologist according to Michels' classification. Common hepatic arterial anatomy (type I) was observed in 95 donors (63.3%). Other arterial variations were determined in the remaining 55 donors (36.6%). The second common variation was type XI which did not match with the description of Michels' classification variation in 15 donors (10%). The remaining variations described in Michels' classification were seen at lower rates. Type VII or X variation was not seen. MDCTA is a useful method to identify the blood supply of the liver before the liver transplantations, and surgeons can make their plan on the basis of CT data. PMID:26910605

  18. Advances of multidetector computed tomography in the characterization and staging of renal cell carcinoma

    PubMed Central

    Tsili, Athina C; Argyropoulou, Maria I

    2015-01-01

    Renal cell carcinoma (RCC) accounts for approximately 90%-95% of kidney tumors. With the widespread use of cross-sectional imaging modalities, more than half of RCCs are detected incidentally, often diagnosed at an early stage. This may allow the planning of more conservative treatment strategies. Computed tomography (CT) is considered the examination of choice for the detection and staging of RCC. Multidetector CT (MDCT) with the improvement of spatial resolution and the ability to obtain multiphase imaging, multiplanar and three-dimensional reconstructions in any desired plane brought about further improvement in the evaluation of RCC. Differentiation of RCC from benign renal tumors based on MDCT features is improved. Tumor enhancement characteristics on MDCT have been found closely to correlate with the histologic subtype of RCC, the nuclear grade and the cytogenetic characteristics of clear cell RCC. Important information, including tumor size, localization, and organ involvement, presence and extent of venous thrombus, possible invasion of adjacent organs or lymph nodes, and presence of distant metastases are provided by MDCT examination. The preoperative evaluation of patients with RCC was improved by depicting the presence or absence of renal pseudocapsule and by assessing the possible neoplastic infiltration of the perirenal fat tissue and/or renal sinus fat compartment. PMID:26120380

  19. Multidetector Computed Tomography Features in Differentiating Exophytic Renal Angiomyolipoma from Retroperitoneal Liposarcoma

    PubMed Central

    Wang, Qiushi; Juan, Yu-Hsiang; Li, Yong; Xie, Jia-Jun; Liu, Hui; Huang, Hongfei; Liu, Zaiyi; Zheng, Junhui; Saboo, Ujwala S.; Saboo, Sachin S.; Liang, Changhong

    2015-01-01

    Abstract This study aims to evaluate the multidetector computed tomography (CT) imaging features in differentiating exophytic renal angiomyolipoma (AML) from retroperitoneal liposarcoma. We retrospectively enrolled 42 patients with confirmed exophytic renal AML (31 patients) or retroperitoneal liposarcoma (11 patients) during 8 years period to assess: renal parenchymal defect at site of tumor contact, supply from branches of renal artery, tumoral vessel extending through the renal parenchyma, dilated intratumoral vessels, hemorrhage, non–fat-containing intratumoral nodules with postcontrast enhancement, calcification, renal sinus enlargement, anterior displacement of kidneys, and other associated AML. Renal parenchymal defect, renal arterial blood supply, tumoral vessel through the renal parenchyma, dilated intratumoral vessels, intratumoral/perirenal hemorrhage, renal sinus enlargement, and associated AML were seen only or mainly in exophytic renal AML (all P value < 0.05); however, non–fat-attenuating enhancing intratumoral nodules, intratumoral calcification, and anterior displacement of the kidney were more common in liposarcoma (all P value < 0.05). AMLs reveal renal parenchymal defect at the site of tumor contact, supply from renal artery, tumoral vessel extending through the renal parenchyma, dilated intratumoral vessels, intratumoral and/or perirenal hemorrhage, renal sinus enlargement, and associated AML. Non–fat-attenuating enhancing intratumoral nodules, intratumoral calcifications, and anterior displacement of kidney were more commonly seen in liposarcoma. PMID:26376398

  20. To assess vascular calcification in the patients of hypoparathyroidism using multidetector computed tomography scan

    PubMed Central

    Agarwal, Pooja; Prakash, Mahesh; Singhal, Manphool; Bhadada, Sanjay Kumar; Gupta, Yashdeep; Khandelwal, Niranjan

    2015-01-01

    Background: Our pilot data showed an increased intima media thickness in the patients with sporadic idiopathic hypoparathyroidism (SIH). Alteration in homeostasis of calcium, phosphate, and parathyroid hormone (PTH) may predispose to increase the risk of cardiovascular morbidity and mortality. The data on objective assessment of this increased risk is however lacking. Objective: To assess the effect of altered calcium, phosphate, and PTH homeostasis in the patients with SIH on coronary calcium score (a marker of increase vascular risk) by multidetector computed tomography scan (MDCT). Methods: In this case-control study, we measured coronary CT calcium score in 30 patients of SIH and compared with 40 age and sex matched healthy subjects. Correlation of coronary calcium score with biochemical parameters was evaluated. Results: Three of the 30 cases (10%) with SIH were found to have coronary artery calcification (CAC) of varying degree, whereas none of the control showed CAC (P = 0.07). The patients with CAC had significantly lower serum calcium levels (albumin corrected), as compared to the patients without CAC. Inverse correlation of CAC was found with serum calcium levels. No correlation was found with other biochemical parameters. Conclusion: The vascular risk is increased in the patients with SIH as assessed by coronary calcium score measured by MDCT. Low serum calcium levels might be a predisposing factor for this increased risk. PMID:26693429

  1. A Structural and Functional Assessment of the Lung via Multidetector-Row Computed Tomography

    PubMed Central

    Hoffman, Eric A.; Simon, Brett A.; McLennan, Geoffrey

    2006-01-01

    With advances in multidetector-row computed tomography (MDCT), it is now possible to image the lung in 10 s or less and accurately extract the lungs, lobes, and airway tree to the fifth- through seventh-generation bronchi and to regionally characterize lung density, texture, ventilation, and perfusion. These methods are now being used to phenotype the lung in health and disease and to gain insights into the etiology of pathologic processes. This article outlines the application of these methodologies with specific emphasis on chronic obstructive pulmonary disease. We demonstrate the use of our methods for assessing regional ventilation and perfusion and demonstrate early data that show, in a sheep model, a regionally intact hypoxic pulmonary vasoconstrictor (HPV) response with an apparent inhibition of HPV regionally in the presence of inflammation. We present the hypothesis that, in subjects with pulmonary emphysema, one major contributing factor leading to parenchymal destruction is the lack of a regional blunting of HPV when the regional hypoxia is related to regional inflammatory events (bronchiolitis or alveolar flooding). If maintaining adequate blood flow to inflamed lung regions is critical to the nondestructive resolution of inflammatory events, the pathologic condition whereby HPV is sustained in regions of inflammation would likely have its greatest effect in the lung apices where blood flow is already reduced in the upright body posture. PMID:16921136

  2. Multidetector computed tomography angiography of the celiac trunk and hepatic arterial system: normal anatomy and main variants *

    PubMed Central

    Araujo Neto, Severino Aires; de Mello Júnior, Carlos Fernando; Franca, Henrique Almeida; Duarte, Cláudia Martina Araújo; Borges, Rafael Farias; de Magalhães, Ana Guardiana Ximenes

    2016-01-01

    Although digital angiography remains as the gold standard for imaging the celiac arterial trunk and hepatic arteries, multidetector computed tomography in association with digital images processing by software resources represents a useful tool particularly attractive for its non invasiveness. Knowledge of normal anatomy as well as of its variations is helpful in images interpretation and to address surgical planning on a case-by-case basis. The present essay illustrates several types of anatomical variations of celiac trunk, hepatic artery and its main branches, by means of digitally reconstructed computed tomography images, correlating their prevalence in the population with surgical implications. PMID:26929461

  3. MULTIDETECTOR-ROW COMPUTED TOMOGRAPHIC CHARACTERISTICS OF PRESUMED PREURETERAL VENA CAVA IN CATS.

    PubMed

    Pey, Pascaline; Marcon, Oriana; Drigo, Michele; Specchi, Swan; Bertolini, Giovanna

    2015-01-01

    Preureteral vena cava (circumcaval ureter, retrocaval ureter) occurs in a third of the feline population and has been associated with ureteral strictures in humans. The aim of this retrospective cross-sectional study was to describe the contrast-enhanced multidetector row computed tomographic (MDCT) characteristics of presumed preureteral vena cava in a group of cats. Medical records from two institutions located in different continents were searched from 2010-2013 for cases with complete contrast-enhanced MDCT examinations of the abdomen (i.e. included the entire course of the ureters and prerenal and renal segments of the caudal vena cava) and a diagnosis of preureteral caudal vena cava. For cases meeting inclusion criteria, CT scan data were retrieved and characteristics of the preureteral caudal vena cava were recorded. Presence of concomitant renal or ureteral diseases was also recorded. A total of 272 cats had contrast-enhanced abdominal CT scans during the study period and of these, 68 cats (22.43 ± 4.96%) had a diagnosis of presumed preureteral vena cava. In all affected cats, a "reverse-J ureter" was observed, i.e. a ureter running medially at the level of L4-5, passing dorsally to the caudal vena cava and then exiting ventrally between the caudal vena cava and aorta returning to its normal position. Having a preureteral vena cava resulted in an increased risk for concurrent urinary signs (OR = 3.00; CI: 95%; 1.28-6.99; P = 0.01). Findings supported the use of contrast-enhanced MDCT for characterizing morphology of preureteral vena cava and its relation with ureters in cats. PMID:25786990

  4. Multidetector computed tomography in the evaluation of pediatric acute abdominal pain in the emergency department.

    PubMed

    Lin, Wei-Ching; Lin, Chien-Heng

    2016-06-01

    The accurate diagnosis of pediatric acute abdominal pain is one of the most challenging tasks in the emergency department (ED) due to its unclear clinical presentation and non-specific findings in physical examinations, laboratory data, and plain radiographs. The objective of this study was to evaluate the impact of abdominal multidetector computed tomography (MDCT) performed in the ED on pediatric patients presenting with acute abdominal pain. A retrospective chart review of children aged <18 years with acute abdominal pain who visited the emergency department and underwent MDCT between September 2004 and June 2007 was conducted. Patients with a history of trauma were excluded. A total of 156 patients with acute abdominal pain (85 males and 71 females, age 1-17 years; mean age 10.9 ± 4.6 years) who underwent abdominal MDCT in the pediatric ED during this 3-year period were enrolled in the study. One hundred and eighteen patients with suspected appendicitis underwent abdominal MDCT. Sixty four (54.2%) of them had appendicitis, which was proven by histopathology. The sensitivity of abdominal MDCT for appendicitis was found to be 98.5% and the specificity was 84.9%. In this study, the other two common causes of nontraumatic abdominal emergencies were gastrointestinal tract (GI) infections and ovarian cysts. The most common etiology of abdominal pain in children that requires imaging with abdominal MDCT is appendicitis. MDCT has become a preferred and invaluable imaging modality in evaluating uncertain cases of pediatric acute abdominal pain in ED, in particular for suspected appendicitis, neoplasms, and gastrointestinal abnormalities. PMID:27154197

  5. Tendon entrapments and dislocations in ankle and hindfoot fractures: evaluation with multidetector computed tomography.

    PubMed

    Ballard, David H; Campbell, Kevin J; Blanton, Lee E; Williams, Jason T; Sangster, Guillermo; Hollister, Anne M; Simoncini, Alberto A

    2016-08-01

    The purpose of this study was to assess the incidence of tendon entrapments and tendon dislocations associated with ankle and hindfoot fractures in patients studied by multidetector computed tomography (MDCT). Additionally, we describe particular tendon injuries associated with specific fractures. This was a retrospective review of all individuals with a trauma-protocol CT for suspected ankle and/or hindfoot fractures during a consecutive 41-month time period at a single Level I Trauma Center. Each patient's images were evaluated by two radiologists and an orthopedic surgeon for tendon entrapment, tendon dislocation, and bone(s) fractured or dislocated. There were 398 patients with ankle and/or hindfoot fractures that showed tendon entrapment or dislocation in 64 (16.1 %) patients. There were 30 (46.9 %) patients with 40 tendon entrapments, 31 (48.4 %) patients with 59 tendon dislocations, and three (4.7 %) patients with both tendon entrapment and dislocation. All patients with tendon entrapments were seen with either pilon fractures and/or a combination of posterior, medial, or lateral malleolar fractures. The most frequently entrapped tendon was the posterior tibialis tendon (PTT) in 27 patients (27/30, 90.0 %). The peroneal tendons were the most frequently dislocated, representing 27 (87.1 %) of patients with tendon dislocation; all resulted from a talar or calcaneal fracture or subluxation. This study demonstrates that tendon entrapments and tendon dislocations are commonly seen in complex fractures of the ankle and hindfoot. Pilon fractures were associated with the majority of tendon entrapments, whereas calcaneus fractures were associated with the majority of tendon dislocations. PMID:27234977

  6. Anthropometric Assessment of Neck Adipose Tissue and Airway Volume Using Multidetector Computed Tomography

    PubMed Central

    Maresky, Hillel S.; Sharfman, Zachary; Ziv-Baran, Tomer; Gomori, J.M.; Copel, Laurian; Tal, Sigal

    2015-01-01

    Abstract Neck adiposity tissue volume (NATV) accumulation is an indicator for metabolic syndrome and cardiovascular disease (CVD). Neck circumference is a poor measure of NATV, and a quantifier for this entity has not yet been established. To evaluate volumetric quantification by multidetector computed tomography (MDCT) as a reproducible anthropometric tool to measure NATV and airway volume (AWV). A total of 519 patients, including a subset of 70 random patients who underwent head and neck CT scanning in our hospital within 1 year (2013), were studied. Included patients were all those undergoing nonenhanced CT (NECT) or CT angiography (CTA). Neck cross-sectional areas (NCSA) were measured at 2 separate levels of the neck, and 3D postprocessing tissue reconstruction was performed, and NATV and AWVs were quantified volumetrically for all patients within the year. The average NCSA at the level of the soft palate and thyroid cartilage was 22,579 and 14,500 mm2, respectively. NATV when compared to the upper and lower levels of NCSA showed correlations of 0.64 and 0.79, respectively (P < 0.001). Interobserver analysis showed mean deviations of 0.46% and 0.32% for NATV and AWV, respectively. A strong correlation between NATV and body mass index (BMI) was found (r = 0.658, P < 0.001), and the top quartile of NATV:AWV patients (out of 519 patients) displayed a statistically significant mortality rate during 670 days of follow-up (d = 7.5%, P = 0.032). After adjustment for age and gender, the association between NATV:AWV and mortality was close to significant (P = 0.072). Volumetric quantification of NATV and AWV is a reproducible and prognostic anthropometric tool, as a high NATV:AWV demonstrated a significant risk factor for mortality; future research may further advance our understanding of this phenomenon. PMID:26559286

  7. Multidetector Computed Tomography and Magnetic Resonance Imaging Evaluation of Craniovertebral junction Abnormalities

    PubMed Central

    Dhadve, Rajshree U.; Garge, Shaileshkumar S.; Vyas, Pooja D.; Thakker, Nirav R.; Shah, Sonali H.; Jaggi, Sunila T.; Talwar, Inder A.

    2015-01-01

    Background: Craniovertebral junction (CVJ) abnormalities constitute an important group of treatable neurological disorders with diagnostic dilemma. Their precise diagnosis, identification of probable etiology, and pretreatment evaluation significantly affects prognosis and quality of life of patients. Aims: The study was to classify various craniovertebral junction disorders according to their etiology and to define the importance of precise diagnosis for pretreatment evaluation with multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI). Materials and Methods: This is a prospective observational study of 62 patients referred to our department between October 2012 and September 2014. All patients suspected to have a craniovertebral junction disorder were included in the study, from all age groups and both genders. Detailed clinical history was taken. Radiographs of cervical spine were collected if available. All patients were subjected to MDCT and/or MRI. Results: In our study of 62 patients; 39 were males and 23 were females, with male to female ratio of 1.6:1. Most common age group was 2nd -3rd decade (19 patients, 30.64%). Developmental anomalies (33 patients, 53.22%) were the most common etiology group followed by traumatic (10 patients, 16.12%), degenerative (eight patients, 12.90%), infective (four patients, 6.45%), inflammatory and neoplastic (three patients each, 4.8%), and no cause found in one patient. Conclusions: CVJ abnormalities constitute an important group of treatable neurological disorders, especially in certain ethnic groups and are approached with much caution by clinicians. Thus, it is essential that radiologists should be able to make a precise diagnosis of craniovertebral junction abnormalities, classify them into etiological group, and rule out important mimickers on MDCT and/or MRI, as this information ultimately helps determine the management of such abnormalities, prognosis, and quality of life of patients. PMID

  8. Multidetector computed tomography features of pancreatic metastases from leiomyosarcoma: Experience at a tertiary cancer center

    PubMed Central

    Suh, Chong Hyun; Keraliya, Abhishek; Shinagare, Atul B; Kim, Kyung Won; Ramaiya, Nikhil H; Tirumani, Sree Harsha

    2016-01-01

    AIM: To describe the multidetector computed tomography features of pancreatic metastasis from leiomyosarcoma (LMS). METHODS: Between January 1995 and December 2012, 13 consecutive patients (11 women, 2 men; mean age of 57 years; range, 38-78 years) with pancreatic metastases from LMS were included in our study. Imaging features including location, number, largest dimension, tumor attenuation and enhancement characteristics, presence of necrosis, pancreatic ductal dilatation, common bile duct (CBD) dilatation, presence of pancreatitis, and atrophy were documented. RESULTS: The most common site of origin of the pancreatic metastases from LMS was uterus (38.5%), followed by retroperitoneum (30.8%) and extremity (23.1%). None of the patients in our study had pancreas as the first site of metastasis. All patients developed pancreatic metastases at a median interval of 24 mo. Pancreatic metastases from LMS were solitary in 8/13 patients and multiple in 5/13 patients, had no predilection for any part of the pancreas, were hypovascular on arterial phase in 10/13 patients and associated with pancreatic duct dilatation in 3/13 patients. None had CBD dilatation. None of the pancreatic metastases in LMS cohort caused pancreatitis, and atrophy. Median duration of follow-up was 19 mo for LMS cohort during which two patients underwent resection of metastasis (median survival 45 mo) while the remaining underwent systemic therapy (median survival 13 mo). CONCLUSION: Pancreatic metastases from LMS are often solitary and hypovascular masses and less commonly associated with pancreatic ductal dilatation, CBD dilatation, pancreatitis or pancreatic atrophy. Surgical resection of solitary LMS pancreatic metastasis can be considered due to the long survival of these patients. PMID:27027985

  9. A case of fatal sigmoid volvulus visualized on postmortem radiography: The importance of image optimization with multidetector computed tomography.

    PubMed

    Usui, Akihito; Kawasumi, Yusuke; Hosokai, Yoshiyuki; Ishizuka, Yuya; Ikeda, Tomoya; Saito, Haruo; Funayama, Masato

    2016-03-01

    This report describes the case of a man who developed fatal sigmoid volvulus that was identified on postmortem radiography before forensic autopsy. Postmortem radiography is useful for visualizing the body prior to autopsy. We discuss postmortem multidetector computed tomography that was tailored for optimum image quality to allow reconstruction of the fatal findings in multiple axes and in three dimensions, helping to pinpoint the anatomical sites of interest. This involves techniques such as manipulation of the scanning beam pitch and overlapping CT section acquisition. These techniques are best performed by personnel with CT technology training. PMID:26980251

  10. Incidental finding of a papillary fibroelastoma on the aortic valve in 16 slice multi-detector row computed tomography.

    PubMed

    Bootsveld, A; Puetz, J; Grube, E

    2004-06-01

    Papillary fibroelastoma (PFE) is a benign, rare, gelatinous tumour derived from the endocardium, primarily the cardiac valves, which is usually diagnosed by high resolution echocardiography. Although rarely clinically symptomatic, PFEs have a potential for coronary ischaemia, systemic embolisation with neurologic symptoms, and sometimes valvar dysfunction. There are reports of coronary occlusion and even sudden cardiac death due to a ball valve phenomenon on the coronary ostia. This report describes the characteristics of a PFE with multidetector 16 slice computed tomography and 1.5 Tesla cardiac magnetic resonance imaging. PMID:15145899

  11. Rectal cancer staging: Multidetector-row computed tomography diagnostic accuracy in assessment of mesorectal fascia invasion

    PubMed Central

    Ippolito, Davide; Drago, Silvia Girolama; Franzesi, Cammillo Talei; Fior, Davide; Sironi, Sandro

    2016-01-01

    AIM: To assess the diagnostic accuracy of multidetector-row computed tomography (MDCT) as compared with conventional magnetic resonance imaging (MRI), in identifying mesorectal fascia (MRF) invasion in rectal cancer patients. METHODS: Ninety-one patients with biopsy proven rectal adenocarcinoma referred for thoracic and abdominal CT staging were enrolled in this study. The contrast-enhanced MDCT scans were performed on a 256 row scanner (ICT, Philips) with the following acquisition parameters: tube voltage 120 KV, tube current 150-300 mAs. Imaging data were reviewed as axial and as multiplanar reconstructions (MPRs) images along the rectal tumor axis. MRI study, performed on 1.5 T with dedicated phased array multicoil, included multiplanar T2 and axial T1 sequences and diffusion weighted images (DWI). Axial and MPR CT images independently were compared to MRI and MRF involvement was determined. Diagnostic accuracy of both modalities was compared and statistically analyzed. RESULTS: According to MRI, the MRF was involved in 51 patients and not involved in 40 patients. DWI allowed to recognize the tumor as a focal mass with high signal intensity on high b-value images, compared with the signal of the normal adjacent rectal wall or with the lower tissue signal intensity background. The number of patients correctly staged by the native axial CT images was 71 out of 91 (41 with involved MRF; 30 with not involved MRF), while by using the MPR 80 patients were correctly staged (45 with involved MRF; 35 with not involved MRF). Local tumor staging suggested by MDCT agreed with those of MRI, obtaining for CT axial images sensitivity and specificity of 80.4% and 75%, positive predictive value (PPV) 80.4%, negative predictive value (NPV) 75% and accuracy 78%; while performing MPR the sensitivity and specificity increased to 88% and 87.5%, PPV was 90%, NPV 85.36% and accuracy 88%. MPR images showed higher diagnostic accuracy, in terms of MRF involvement, than native axial images

  12. Precision of dosimetry-related measurements obtained on current multidetector computed tomography scanners

    SciTech Connect

    Mathieu, Kelsey B.; McNitt-Gray, Michael F.; Zhang, Di; Kim, Hyun J.; Cody, Dianna D.

    2010-08-15

    Purpose: Computed tomography (CT) intrascanner and interscanner variability has not been well characterized. Thus, the purpose of this study was to examine the within-run, between-run, and between-scanner precision of physical dosimetry-related measurements collected over the course of 1 yr on three different makes and models of multidetector row CT (MDCT) scanners. Methods: Physical measurements were collected using nine CT scanners (three scanners each of GE VCT, GE LightSpeed 16, and Siemens Sensation 64 CT). Measurements were made using various combinations of technical factors, including kVp, type of bowtie filter, and x-ray beam collimation, for several dosimetry-related quantities, including (a) free-in-air CT dose index (CTDI{sub 100,air}); (b) calculated half-value layers and quarter-value layers; and (c) weighted CT dose index (CTDI{sub w}) calculated from exposure measurements collected in both a 16 and 32 cm diameter CTDI phantom. Data collection was repeated at several different time intervals, ranging from seconds (for CTDI{sub 100,air} values) to weekly for 3 weeks and then quarterly or triannually for 1 yr. Precision of the data was quantified by the percent coefficient of variation (%CV). Results: The maximum relative precision error (maximum %CV value) across all dosimetry metrics, time periods, and scanners included in this study was 4.33%. The median observed %CV values for CTDI{sub 100,air} ranged from 0.05% to 0.19% over several seconds, 0.12%-0.52% over 1 week, and 0.58%-2.31% over 3-4 months. For CTDI{sub w} for a 16 and 32 cm CTDI phantom, respectively, the range of median %CVs was 0.38%-1.14% and 0.62%-1.23% in data gathered weekly for 3 weeks and 1.32%-2.79% and 0.84%-2.47% in data gathered quarterly or triannually for 1 yr. Conclusions: From a dosimetry perspective, the MDCT scanners tested in this study demonstrated a high degree of within-run, between-run, and between-scanner precision (with relative precision errors typically well

  13. Quantitative Analysis of Intraventricular Dyssynchrony Using Wall Thickness by Multidetector Computed Tomography

    PubMed Central

    Truong, Quynh A.; Singh, Jagmeet P.; Cannon, Christopher P.; Sarwar, Ammar; Nasir, Khurram; Auricchio, Angelo; Faletra, Francesco F.; Sorgente, Antonio; Conca, Cristina; Moccetti, Tiziano; Handschumacher, Mark; Brady, Thomas J.; Hoffmann, Udo

    2009-01-01

    OBJECTIVES We sought to determine the feasibility of cardiac computed tomography (CT) to detect significant differences in the extent of left ventricular dyssynchrony in heart failure (HF) patients with wide QRS, HF patients with narrow QRS, and age-matched controls. BACKGROUND The degree of mechanical dyssynchrony has been suggested as a predictor of response to cardiac resynchronization therapy. There have been no published reports of dyssynchrony assessment with the use of CT. METHODS Thirty-eight subjects underwent electrocardiogram-gated contrast-enhanced 64-slice multidetector CT. The left ventricular endocardial and epicardial boundaries were delineated from short-axis images reconstructed at 10% phase increments of the cardiac cycle. Global and segmental CT dyssynchrony metrics that used changes in wall thickness, wall motion, and volume over time were assessed for reproducibility. We defined a global metric using changes in wall thickness as the dyssynchrony index (DI). RESULTS The DI was the most reproducible metric (interobserver and intraobserver intraclass correlation coefficients ≥0.94, p < 0.0001) and was used to determine differences between the 3 groups: HF-wide QRS group (ejection fraction [EF] 22 ± 8%, QRS 163 ± 28 ms), HF-narrow QRS (EF 26 ± 7%, QRS 96 ± 11 ms), and age-matched control subjects (EF 64 ± 5%, QRS 87 ± 9 ms). Mean DI was significantly different between the 3 groups (HF-wide QRS: 152 ± 44 ms, HF-narrow QRS: 121 ± 58 ms, and control subjects: 65 ± 12 ms; p < 0.0001) and greater in the HF-wide QRS (p < 0.0001) and HF-narrow QRS (p = 0.005) groups compared with control subjects. We found that DI had a good correlation with 2-dimensional (r = 0.65, p = 0.012) and 3-dimensional (r = 0.68, p = 0.008) echocardiographic dyssynchrony. CONCLUSIONS Quantitative assessment of global CT-derived DI, based on changes in wall thickness over time, is highly reproducible and renders significant differences between subjects most likely to

  14. The effect of z overscanning on patient effective dose from multidetector helical computed tomography examinations

    SciTech Connect

    Tzedakis, A.; Damilakis, J.; Perisinakis, K.; Stratakis, J.; Gourtsoyiannis, N.

    2005-06-15

    z overscanning in multidetector (MD) helical CT scanning is prerequisite for the interpolation of acquired data required during image reconstruction and refers to the exposure of tissues beyond the boundaries of the volume to be imaged. The aim of the present study was to evaluate the effect of z overscanning on the patient effective dose from helical MD CT examinations. The Monte Carlo N-particle radiation transport code was employed in the current study to simulate CT exposure. The validity of the Monte Carlo simulation was verified by (a) a comparison of calculated and measured standard computed tomography dose index (CTDI) dosimetric data, and (b) a comparison of calculated and measured dose profiles along the z axis. CTDI was measured using a pencil ionization chamber and head and body CT phantoms. Dose profiles along the z axis were obtained using thermoluminescence dosimeters. A commercially available mathematical anthropomorphic phantom was used for the estimation of effective doses from four standard CT examinations, i.e., head and neck, chest, abdomen and pelvis, and trunk studies. Data for both axial and helical modes of operation were obtained. In the helical mode, z overscanning was taken into account. The calculated effective dose from a CT exposure was normalized to CTDI{sub freeinair}. The percentage differences in the normalized effective dose between contiguous axial and helical scans with pitch=1, may reach 13.1%, 35.8%, 29.0%, and 21.5%, for head and neck, chest, abdomen and pelvis, and trunk studies, respectively. Given that the same kilovoltage and tube load per rotation were used in both axial and helical scans, the above differences may be attributed to z overscanning. For helical scans with pitch=1, broader beam collimation is associated with increased z overscanning and consequently higher normalized effective dose value, when other scanning parameters are held constant. For a given beam collimation, the selection of a higher value of

  15. Clinical Structural Anatomy of the Inferior Pyramidal Space Reconstructed Within the Cardiac Contour Using Multidetector-Row Computed Tomography.

    PubMed

    Mori, Shumpei; Fukuzawa, Koji; Takaya, Tomofumi; Takamine, Sachiko; Ito, Tatsuro; Fujiwara, Sei; Nishii, Tatsuya; Kono, Atsushi K; Yoshida, Akihiro; Hirata, Ken-Ichi

    2015-07-01

    Although many studies have described the detailed anatomy of the inferior pyramidal space, it may not be easy for cardiologists who have few chances to study cadaveric hearts to understand the correct morphology of the structure. The inferior pyramidal space is the part of extracardiac fibro-adipose tissue wedging between the 4 cardiac chambers from the diaphragmatic surface of the heart. Many cardiologists have interests in pericardial adipose tissue, but the inferior pyramidal space seems to have been neglected. A number of important structures, including the coronary sinus, atrioventricular node, atrioventricular nodal artery, membranous septum, muscular atrioventricular sandwich (previously called the "muscular atrioventricular septum"), atrial septum, ventricular septum, aortic valvar complex, mitral valvar attachment, and tricuspid valvar attachment are associated with the inferior pyramidal space. We previously revealed its 3-dimensional live anatomy using multidetector-row computed tomography. Moreover, the 3-dimensional understanding of the anatomy in association with the cardiac contour is important from the viewpoints of clinical cardiac electrophysiology. The purpose of this article is to demonstrate extended findings regarding the clinical structural anatomy of the inferior pyramidal space, which was reconstructed in combination with the cardiac contour using multidetector-row computed tomography, and discuss the clinical implications of the findings. PMID:25884276

  16. Detection of root perforations using conventional and digital intraoral radiography, multidetector computed tomography and cone beam computed tomography

    PubMed Central

    Eskandarloo, Amir; Noruzi-Gangachin, Maruf; Khajeh, Samira

    2015-01-01

    Objectives This study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth. Materials and Methods Mesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test. Results The sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed. Conclusions If it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended. PMID:25671214

  17. [The role of multidetector computer tomography in diagnosis of acute pancreatitis].

    PubMed

    Lohanikhina, K Iu; Hordiienko, K P; Kozarenko, T M

    2014-10-01

    With the objective to improve the diagnostic semiotics of an acute pancreatitis (AP) 35 patients were examined, using 64-cut computeric tomograph Lightspeed VCT (GE, USA) with intravenous augmentation in arterial and portal phases. Basing on analysis of the investigations conducted, using multidetector computeric tomography (MDCT), the AP semiotics was systematized, which is characteristic for oedematous and destructive forms, diagnosed in 19 (44.2%) and 16 (45.8%) patients, accordingly. The procedure for estimation of preservation of the organ functional capacity in pancreonecrosis pres- ence was elaborated, promoting rising of the method diagnostic efficacy by 5.3 - 9.4%. PMID:25675779

  18. Validation of a paediatric thyroid phantom using different multidetector computed tomography models

    NASA Astrophysics Data System (ADS)

    Alsabbagh, M.; Ng, L. Y.; Tajuddin, A. A.; Manap, M. A.; Zainon, R.

    2016-03-01

    The aim of this study was to compare the attenuation values of a fabricated paediatric thyroid phantom material using different MDCT models. A paediatric thyroid phantom was designed to mimic the shape and size of a paediatric patient with an age of 9 years using high- density Polyethylene as the phantom material. The fabricated phantom was scanned using two different multidetector CT scanners (16- and 128-row detectors). The CT numbers were evaluated and the mass attenuation coefficients (μ/ρ) of the phantom material were obtained at each applied energy from each scanner. The results were compared with the tables of the National Institute of Standards and Technology (NIST). The CTs of 16- and 128-row detectors showed that the obtained attenuation values are very similar to the NIST's values. However, the CT of the 128-row detectors showed a slightly much closer match to the NIST's values. This refers to the type and quality of the electronic connections between the detectors. Furthermore, the type and number of detectors (16- and 128-detectors) could affect the details and quality of the output images. The results show that different multidetector CTs can be used to validate the phantom and determine the mass attenuation coefficients of its material.

  19. Epidemiology and association of vascular and valvular calcium quantified by multidetector computed tomography in elderly asymptomatic subjects.

    PubMed

    Cury, Ricardo C; Ferencik, Maros; Hoffmann, Udo; Ferullo, Ashley; Moselewski, Fabian; Abbara, Suhny; Booth, Sarah L; O'Donnell, Christopher J; Brady, Thomas J; Achenbach, Stephan

    2004-08-01

    The epidemiology of and association between vascular and valvular calcium as quantified by multidetector computed tomography (MDCT) were studied in 416 elderly subjects with no history of coronary artery disease. Coronary calcium (CC), descending thoracic aortic calcium (DTAC), aortic valve calcium (AVC), and mitral valve calcium (MVC) were present in 282 (68%), 214 (51%), 152 (37%), and 68 (16%) subjects, respectively. Multiple logistic regression analysis showed that after adjusting for age and gender, subjects with AVC (odds ratio [OR] 2.3), MVC (OR 2.81), and DTAC (OR 2.79) were independently and significantly more likely to have CC. Further evidence is provided for the notion that calcifications in those regions are associated and that MDCT can be used as a tool for the global assessment of vascular and valvular calcium. PMID:15276102

  20. Autopsy radiography: digital radiographs (DR) vs multidetector computed tomography (MDCT) in high-velocity gunshot-wound victims.

    PubMed

    Harcke, H Theodore; Levy, Angela D; Abbott, Robert M; Mallak, Craig T; Getz, John M; Champion, Howard R; Pearse, Lisa

    2007-03-01

    This study compared full-body digital radiography (DR) with multidetector computed tomography (MDCT) in the postmortem evaluation of gunshot wound (GSW) victims. Thirteen consecutive male GSW victims (mean age, 27 years) had full-body DR and MDCT prior to routine autopsy. DR successfully identified all metallic fragments, but MDCT was superior in its ability to precisely determine location because it provided 3-dimensional anatomic localization. In all cases, MDCT more accurately assessed organ injuries and wound tracks. Both DR and MDCT are limited in classifying multiple wounds and major vessel injury, but MDCT is generally superior to DR. MDCT shows significant advantages over DR in the forensic evaluation of GSW victims. This is particularly advantageous for the pathologist retrieving metallic fragments and for describing fracture detail accurately. Use of MDCT instead of radiographs will require medical examiners to become familiar with reading cross-sectional images. PMID:17325457

  1. Observational case series: an algorithm incorporating multidetector computed tomography in the medicolegal investigation of human remains after a natural disaster.

    PubMed

    Berran, Philip J; Mazuchowski, Edward L; Marzouk, Abubakr; Harcke, H Theodore

    2014-07-01

    An algorithm incorporating multidetector computed tomography (MDCT), digital radiographs, and external examination was used to triage cases for noninvasive or complete autopsy after a natural disaster. The algorithm was applied to 27 individuals who died during or soon after the earthquake that struck the Republic of Haiti on January 12, 2010. Of the 27 cases reviewed, 7 (26%) required a complete autopsy to determine cause and manner of death. In the remaining 20 (74%), cause and manner of death were determined with a reasonable degree of medical certainty after review of circumstances, an external examination, and postmortem imaging by MDCT and digital radiography (noninvasive autopsy). MDCT was particularly useful in detecting skeletal fractures caused by blunt force injury which were not evident on digital radiographs. The algorithm incorporating postmortem MDCT can be useful in the triage of human remains for autopsy after a natural disaster. PMID:24684535

  2. A Study of Internal Thoracic Arteriovenous Principal Perforators by Using Multi-detector Row Computed Tomography Angiography

    PubMed Central

    Hashikawa, Kazunobu; Sakakibara, Shunsuke; Onishi, Hiroyuki; Terashi, Hiroto

    2016-01-01

    Objective: There are numerous reports of perforating branches from the intercostal spaces of the internal thoracic vessels. These branches have varying diameters, and a main perforating branch, the principal perforator, most often found in the second or third intercostal space. We report different results based on multi-detector row computed tomography. Methods: We evaluated 121 sides from 70 women scheduled for breast reconstruction with free lower abdominal skin flaps who underwent preoperative multi-detector row computed tomographic scan between June 2008 and June 2015. For primary reconstruction, we analyzed both sides, and for 1-sided secondary reconstruction, we analyzed only the unaffected side. We evaluated both early arterial phase and late venous phase 5-mm horizontal, cross-sectional, and volume-rendering images for perforation sites and internal thoracic arteriovenous perforating branches’ intercostal space thickness. We analyzed differences in thickness between the internal thoracic arteries and veins and symmetry in cases involving both sides. Results: Venous principal perforators nearly always perforated the same intercostal spaces as accompanying veins of arterial principal perforators (99.2%), forming arteriovenous principal perforators. We found 49 principal perforators in the first intercostal space (37.4%), 52 in the second intercostal space (39.7%), 23 in the third intercostal space (17.6%), 6 in the fourth intercostal space (4.6%), and 1 in the fifth intercostal space (0.7%). Of the 51 cases in which we studied both sides, 25 cases (49%) had principal perforators with bilateral symmetry. Conclusions: In contrast to findings from past reports, we found that internal thoracic arteriovenous principal perforators were often present in almost the same numbers in the first and second intercostal spaces. PMID:26958104

  3. Multi-Detector Row Computed Tomography Findings of Pelvic Congestion Syndrome Caused by Dilated Ovarian Veins

    PubMed Central

    Eren, Suat

    2010-01-01

    Objective: To evaluate the efficacy of multi-detector row CT (MDCT) on pelvic congestion syndrome (PCS), which is often overlooked or poorly visualized with routine imaging examination. Materials and Methods: We evaluated the MDCT features of 40 patients with PCS (mean age, 45 years; range, 29–60 years) using axial, coronal, sagittal, 3D volume-rendered, and Maximum Intensity Projection MIP images. Results: MDCT revealed pelvic varices and ovarian vein dilatations in all patients. Bilateral ovarian vein dilatation was present in 25 patients, and 15 patients had unilateral dilatation. While 12 cases of secondary pelvic varices occurred simultaneously with a retroaortic left renal vein, 10 cases were due solely to a mass obstruction or stenosis of venous structures. Conclusion: MDCT is an effective tool in the evaluation of PCS, and it has more advantages than other imaging modalities. PMID:25610142

  4. Multi-detector computed tomography in the diagnosis and management of acute aortic syndromes

    PubMed Central

    Hallinan, James Thomas Patrick Decourcy; Anil, Gopinathan

    2014-01-01

    Acute aortic syndrome (AAS) is a spectrum of conditions, which may ultimately progress to potentially life-threatening aortic rupture. This syndrome encompasses aortic dissection (AD), intramural haematoma, penetrating atherosclerotic ulcer and unstable thoracic aortic aneurysms. Multi-detector CT (MDCT) is crucial for the diagnosis of AAS, especially in the emergency setting due to its speed, accuracy and ready availability. This review attends to the value of appropriate imaging protocols in obtaining good quality images that can permit a confident diagnosis of AAS. AD is the most commonly encountered AAS and also the one with maximum potential to cause catastrophic outcome if not diagnosed and managed promptly. Hence, this review briefly addresses certain relevant clinical perspectives on this condition. Differentiating the false from the true lumen in AD is often essential; a spectrum of CT findings, e.g., “beak sign”, aortic “cobwebs” that allows such differentiation have been described with explicit illustrations. The value of non enhanced CT scans, especially useful in the diagnosis of an intramural hematoma has also been illustrated. Overlap in the clinical and imaging features of the various conditions presenting as AAS is not unusual. However, on most instances MDCT enables the right diagnosis. On select occasions MRI or trans-esophageal echocardiography may be required as a problem solving tool. PMID:24976936

  5. [PROGNOSTIC VALUE OF SOME HEMOSTASIS-RELATED, HOMOCYSTEINE, HIGH SENSITIVE C R P AND MULTIDETECTOR COMPUTED TOMOGRAPHY PARAMETERS IN PULMONARY EMBOLISM].

    PubMed

    Todua, F; Akhvlediani, M; Vorobiova, E; Baramidze, A; Tsivtsivadze, G; Gachechiladze, D

    2016-05-01

    Nowadays, an arsenal of diagnostic methods is used in diagnosis of pulmonary embolism, which includes x-ray, angiography, perfusion-ventilation scintigraphy, CT and magnetic resonance imaging, Doppler and laboratory studies. Purpose of our study was to evaluate the diagnostic significance of determination of some parameters of hemostasis (D-dimer, Soluble fibrinmonomer complexes, fibrinogen), homocysteine, hs-CRP and multidetector computed tomography in suspected pulmonary embolism. We have examined 54 patients -31 men and 23 women, aged 18 to 76 years, with characteristics of pulmonary embolism. According to our data, Multidetector computed tomography angiopulmonography , measuring D-dimer, fibrinogen and related hyperhomocysteinemia with increased level of hs-CRP may serve as binding, diagnostically significant laboratory markers in the diagnosis and treatment efficacy of pulmonary thromboembolism. PMID:27348165

  6. Stature estimation based on measurements of the sternal medullary cavity using multidetector computed tomography images of Japanese cadavers.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Hayakawa, Mutsumi; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Iwase, Hirotaro

    2014-09-01

    Stature estimation using a skeleton is important for the medicolegal investigation of unidentified human remains. The aims of this study were to identify a correlation between stature and measurements of the sternal medullary cavity using multidetector computed tomography (MDCT) and derive regression equations for stature estimation in the Japanese population. Measurements were conducted on 215 Japanese subjects (107 males, 108 females) who underwent postmortem computed tomography with subsequent forensic autopsy between May 2012 and January 2014. For assessment, MDCT cross-sections through the mid-point of the first costal facets were chosen. The length of a rising diagonal stroke from the bottom left to the top right of the sternal medullary cavity (RS) and the length of a falling diagonal stroke from top left to bottom right of the sternal medullary cavity (FS) were measured. Statistical analyses indicated that both RS and FS were positively correlated with stature regardless of sex. The correlations were stronger for males than for females. The correlation coefficients for RS were higher than those for FS, and standard errors of estimation calculated by regression analysis using RS were lower than those using FS regardless of sex. Measurement of the sternal medullary cavity using MDCT images may be a potentially useful tool for stature estimation, particularly in cases where better predictors such as long bones are not available. PMID:25082372

  7. Feasibility of 320-row multi-detector computed tomography angiography to assess bioabsorbable everolimus-eluting vascular scaffolds.

    PubMed

    Asami, Masahiko; Aoki, Jiro; Serruys, Patrick W; Abizaid, Alexandre; Saito, Shigeru; Onuma, Yoshinobu; Kimura, Takeshi; Simonton, Charles A; Tanabe, Kengo

    2016-04-01

    Coronary computer tomographic angiography (CCTA) for screening intra-arterial vessel disease is gaining rapid clinical acceptance in recent years, but its use for such assessments in metal-stented vessel segments is very limited due to blooming artifacts introduced by the metal. However, vessel segments treated by the polymeric everolimus-eluting bioresorbable vascular scaffolds (Absorb) are readily monitored for intravascular disease over time with CCTA. The data on the accuracy of multi-detector computed tomography (MDCT) in patients treated with Absorb is still sparse. Results on 5 Japanese case studies from ABSORB EXTEND are presented here. Five patients were treated with Absorb, and follow-up angiography was conducted at 8 to 14 months as per routine site standard of practice. 320-row MDCT scan was performed within 1 month before the angiography. By MDCT, all Absorb-treated lesions were clearly evaluated and restenosis were not observed. Minimal diameter and % diameter stenosis were similar between MDCT and quantitative angiography (2.07 ± 0.13 vs. 2.03 ± 0.06 mm, P = 0.86, and 22.5 ± 5.0 vs. 21.5 ± 4.5 %, P = 0.88, respectively). MDCT appears to be feasible and useful for evaluating lumen patency and vessel disease in segments implanted with Absorb at follow-up. PMID:26445951

  8. Thoracic Injuries in earthquake-related versus non-earthquake-related trauma patients: differentiation via Multi-detector Computed Tomography

    PubMed Central

    Dong, Zhi-hui; Yang, Zhi-gang; Chen, Tian-wu; Chu, Zhi-gang; Deng, Wen; Shao, Heng

    2011-01-01

    PURPOSE: Massive earthquakes are harmful to humankind. This study of a historical cohort aimed to investigate the difference between earthquake-related crush thoracic traumas and thoracic traumas unrelated to earthquakes using a multi-detector Computed Tomography (CT). METHODS: We retrospectively compared an earthquake-exposed cohort of 215 thoracic trauma crush victims of the Sichuan earthquake to a cohort of 215 non-earthquake-related thoracic trauma patients, focusing on the lesions and coexisting injuries to the thoracic cage and the pulmonary parenchyma and pleura using a multi-detector CT. RESULTS: The incidence of rib fracture was elevated in the earthquake-exposed cohort (143 vs. 66 patients in the non-earthquake-exposed cohort, Risk Ratio (RR) = 2.2; p<0.001). Among these patients, those with more than 3 fractured ribs (106/143 vs. 41/66 patients, RR = 1.2; p<0.05) or flail chest (45/143 vs. 11/66 patients, RR = 1.9; p<0.05) were more frequently seen in the earthquake cohort. Earthquake-related crush injuries more frequently resulted in bilateral rib fractures (66/143 vs. 18/66 patients, RR = 1.7; p<0.01). Additionally, the incidence of non-rib fracture was higher in the earthquake cohort (85 vs. 60 patients, RR = 1.4; p<0.01). Pulmonary parenchymal and pleural injuries were more frequently seen in earthquake-related crush injuries (117 vs. 80 patients, RR = 1.5 for parenchymal and 146 vs. 74 patients, RR = 2.0 for pleural injuries; p<0.001). Non-rib fractures, pulmonary parenchymal and pleural injuries had significant positive correlation with rib fractures in these two cohorts. CONCLUSIONS: Thoracic crush traumas resulting from the earthquake were life threatening with a high incidence of bony thoracic fractures. The ribs were frequently involved in bilateral and severe types of fractures, which were accompanied by non-rib fractures, pulmonary parenchymal and pleural injuries. PMID:21789386

  9. MULTIDETECTOR-ROW COMPUTED TOMOGRAPHY PATTERNS OF BRONCHOESPHAGEAL ARTERY HYPERTROPHY AND SYSTEMIC-TO-PULMONARY FISTULA IN DOGS.

    PubMed

    Ledda, Gianluca; Caldin, Marco; Mezzalira, Giorgia; Bertolini, Giovanna

    2015-01-01

    Anomalies involving arterial branches in the lungs are one of the causes of hemoptysis in humans and dogs. Congenital and acquired patterns of bronchoesophageal artery hypertrophy have been reported in humans based on CT characteristics. The purpose of this retrospective study was to describe clinical, echocardiographic, and multidetector computed tomography features of bronchoesophageal artery hypertrophy and systemic-to-pulmonary arterial communications in a sample of 14 dogs. Two main vascular patterns were identified in dogs that resembled congenital and acquired conditions reported in humans. Pattern 1 appeared as an aberrant origin of the right bronchoesophageal artery, normal origin of the left one, and enlargement of both the bronchial and esophageal branches that formed a dense network terminating in a pulmonary artery through an orifice. Pattern 2 appeared as a normal origin of both right and left bronchoesophageal arteries, with an enlarged and tortuous course along the bronchi to the periphery of the lung, where they communicated with subsegmental pulmonary arteries. Dogs having Pattern 1 also had paraesophageal and esophageal varices, with the latter being confirmed by videoendoscopy examination. Authors conclude that dogs with Pattern 1 should be differentiated from dogs with other congenital vascular systemic-to-pulmonary connections. Dogs having Pattern 2 should be evaluated for underlying pleural or pulmonary diseases. Bronchoesophageal artery hypertrophy can be accompanied by esophageal venous engorgement and should be included in the differential diagnosis for esophageal and paraesophageal varices in dogs. PMID:25961802

  10. Myocardial bridging of the right coronary artery inside the right atrial myocardium identified by ECG-gated 64-slice multidetector computed tomography angiography.

    PubMed

    Chen, Chien-Cheng; Chen, Huan-Wu; Fu, Chen-Ju; Lin, Fen-Chiung; Wen, Ming-Shien; Liu, Yuan-Chang

    2010-01-01

    A myocardial bridge (MB) is defined as an intramyocardial course of a major epicardial coronary artery, and it is mainly confined to the left ventricle and the left anterior descending coronary artery. There are rare reports of right coronary MB seen during angiographic examination. Herein, we present a 49 year-old man with right coronary artery MB without luminal narrowing in the diastolic and systolic phases of electrocardiography-gated computed tomography images. The value of multi-detector computed tomography for the detection of anatomical variants in the cardiovascular system is further discussed. PMID:20438676

  11. Multidetector computed tomography angiography for assessment of in-stent restenosis: meta-analysis of diagnostic performance

    PubMed Central

    Vanhoenacker, Piet K; Decramer, Isabel; Bladt, Olivier; Sarno, Giovanna; Van Hul, Erik; Wijns, William; Dwamena, Ben A

    2008-01-01

    Background Multi-detector computed tomography angiography (MDCTA)of the coronary arteries after stenting has been evaluated in multiple studies. The purpose of this study was to perform a structured review and meta-analysis of the diagnostic performance of MDCTA for the detection of in-stent restenosis in the coronary arteries. Methods A Pubmed and manual search of the literature on in-stent restenosis (ISR) detected on MDCTA compared with conventional coronary angiography (CA) was performed. Bivariate summary receiver operating curve (SROC) analysis, with calculation of summary estimates was done on a stent and patient basis. In addition, the influence of study characteristics on diagnostic performance and number of non-assessable segments (NAP) was investigated with logistic meta-regression. Results Fourteen studies were included. On a stent basis, Pooled sensitivity and specificity were 0.82(0.72–0.89) and 0.91 (0.83–0.96). Pooled negative likelihood ratio and positive likelihood ratio were 0.20 (0.13–0.32) and 9.34 (4.68–18.62) respectively. The exclusion of non-assessable stents and the strut thickness of the stents had an influence on the diagnostic performance. The proportion of non-assessable stents was influenced by the number of detectors, stent diameter, strut thickness and the use of an edge-enhancing kernel. Conclusion The sensitivity of MDTCA for the detection of in-stent stenosis is insufficient to use this test to select patients for further invasive testing as with this strategy around 20% of the patients with in-stent stenosis would be missed. Further improvement of scanner technology is needed before it can be recommended as a triage instrument in practice. In addition, the number of non-assessable stents is also high. PMID:18671850

  12. Prediction of Small Bowel Obstruction Caused by Bezoars Using Risk Factor Categories on Multidetector Computed Tomographic Findings

    PubMed Central

    Kuang, Lian-qin; Cheng, Cheng

    2016-01-01

    Objectives. The aim of this study was to detect factors associated with small bowel obstruction (SBO) caused by bezoars on multidetector computed tomographic findings. Methods. We retrospectively reviewed 61 patients who had bezoars in the small bowels on MDCT. The patients were divided into SBO patients group and non-SBO patients group. The mean values of the diameter, volume, and CT attenuation as well as location and characteristics of the bezoars were compared between the two groups. Multivariate analysis was performed to determine factors associated with SBO. Results. There were 32 patients (52.5%) in the SBO group and 29 patients (47.5%) in the non-SBO group. The bezoars in the SBO group had greater values of each mean diameter and mean volume than those in the non-SBO group (3.2 ± 0.5 cm versus 1.6 ± 0.7 cm, P < 0.0001, 14.9 ± 6.4 cm3 versus 2.5 ± 2.7 cm3, P < 0.0001, resp.) and had a lower CT attenuation than the non-SBO group (55.5 ± 23.4 versus 173.0 ± 68.0, P < 0.0001). The SBO group had higher prevalence of phytobezoar appearance (75.0% versus 10.3%, P < 0.0001). Major diameters of bezoar and phytobezoar were significant independent risk factors associated with SBO (odds ratio = 36.09, 8.26, resp., and P = 0.0004, 0.044, resp.). Conclusions. Major diameter of bezoar or phytobezoar is a potential risk factor associated with SBO. PMID:27403434

  13. Relationship between Coronary Artery Calcium Score by Multidetector Computed Tomography and Plaque Components by Virtual Histology Intravascular Ultrasound

    PubMed Central

    Choi, Yun Ha; Park, In Hyae; Jeong, Myung Ho; Ahmed, Khurshid; Hwang, Seung Hwan; Lee, Min Goo; Park, Keun-Ho; Sim, Doo Sun; Kim, Ju Han; Ahn, Youngkeun; Cho, Jeong Gwan; Park, Jong Chun; Kang, Jung Chaee

    2011-01-01

    The aim of this study was to evaluate the relationship between coronary artery calcium score (CACS) assessed by multidetector computed tomography (MDCT) and plaque components assessed by virtual histology-intravascular ultrasound (VH-IVUS) in 172 coronary artery disease (CAD) patients with 250 coronary lesions. CACS was assessed according to Agatston scoring method by MDCT and patients were divided into four groups: Group I (CACS = 0 [n = 52]); Group II (CACS = 1-100 [n = 99]); Group III (CACS = 101-400 [n = 84]); and Group IV (CACS > 400 [n = 15]). Total atheroma volume was greatest in Group IV (152 ± 132 µL vs 171 ± 114 µL vs 195 ± 149 µL vs 321±182 µL, P < 0.001). The absolute dense calcium (DC) and necrotic core (NC) volumes were greatest, and relative DC volume was greatest in Group IV (5.5 ± 6.6 µL vs 11.0 ± 10.3 µL vs 15.6 ± 13.6 µL vs 36.6 ± 18.2 µL, P < 0.001, and 14.8 ± 18.2 µL vs 19.5 ± 18.9 µL vs 22.5 ± 19.1 µL vs 41.7 ± 27.9 µL, P < 0.001, and 6.4 ± 5.3% vs 11.0 ± 6.2% vs 14.0 ± 6.5% vs 20.0 ± 7.8%, P < 0.001, respectively). The absolute plaque and DC and NC volumes and the relative DC volume correlated positively with calcium score. CAD patients with high calcium score have more vulnerable plaque components (greater DC and NC-containing plaques) than those with low calcium score. PMID:21860556

  14. Multidetector computed tomography versus platelet/spleen diameter ratio as methods for the detection of gastroesophageal varices

    PubMed Central

    Karatzas, Andreas; Triantos, Christos; Kalafateli, Maria; Marzigie, Misiel; Labropoulou-Karatza, Chryssoula; Thomopoulos, Konstantinos; Petsas, Theodoros; Kalogeropoulou, Christina

    2016-01-01

    Background All patients with liver cirrhosis should undergo screening endoscopy, but there are limitations and this approach places a heavy burden upon endoscopy units. The aim of this study was to compare multidetector computed tomography (MDCT) and the platelet/spleen diameter ratio as non-invasive methods for the detection of gastroesophageal varices. Methods The study included 38 cirrhotics who underwent upper gastrointestinal (GI) endoscopy and MDCT within one month. Two radiologists reviewed the scans, in order to determine the presence and the size of varices. Blood tests and measurement of the spleen maximum diameter were also carried out and the platelet/spleen diameter ratio was calculated. Endoscopy was considered the gold standard and the results of the two methods were compared to it. Results Varices were detected by upper GI endoscopy in 24 of 38 patients. The mean sensitivity and specificity of MDCT for the two observers was 86.1% and 57.1% respectively. In patients with large varices (>5 mm), the sensitivity was 100% (4/4). Using 909 as a cut-off value of the platelet/spleen diameter ratio this method yielded a sensitivity of 56.5% and a specificity of 35.7%. The difference in sensitivity and specificity between the two methods was statistically significant P<0.05. Conclusion MDCT was accurate for the detection of gastroesophageal varices, especially those with clinically significant size (>5 mm), and superior to platelet/spleen diameter ratio. MDCT could replace, in selected patients, upper GI endoscopy as a method for detecting gastroesophageal varices in cirrhotic patients. PMID:26751694

  15. A Case of Coronary Cameral Fistula with Associated Aneurysm: Role of ECG Gated 256- Slice Dual Source Multidetector Computed Tomography in Diagnosis

    PubMed Central

    Garg, Lalit; Rissam, Harmeet Kaur; Puri, Sunil Kumar

    2016-01-01

    We report an interesting case of coronary cameral fistula with associated aneurysmal dilatation of coronary artery. The complete evaluation including anatomical relationships with surrounding vascular and non-vascular structures can be achieved with ECG gated multi-detector computed tomography (MDCT). MDCT has many advantages over echocardiography and digital subtraction catheter angiography, because of its ability to demonstrate the fistula separate from surrounding cardiovascular structures along with any aneurysm or obstruction in its course. Thus, MDCT is emerging as the initial non-invasive imaging technique for comprehensive preoperative evaluation of these rare congenital anomalies for cardiovascular surgeons to achieve better operative assessibity and outcome. PMID:27437325

  16. Ultrasound and multidetector computed tomography of mandibular salivary gland adenocarcinoma in two dogs

    PubMed Central

    Lenoci, D.; Ricciardi, M.

    2015-01-01

    Malignant tumors of the salivary glands are rare in dogs, with adenocarcinoma being the most represented. Parotid and mandibular glands are most commonly affected in dogs. Because of local invasivity and high metastatic potential, preoperative imaging evaluation of mandibular region and tumoral staging is essential along with biopsy sampling. The present manuscript describes the ultrasound and computed tomographic imaging findings of mandibular gland adenocarcinoma in two dogs and discusses their clinical utility. PMID:26753133

  17. Comparison of Multidetector Computed Tomography and Flat-Panel Computed Tomography Regarding Visualization of Cortical Fractures, Cortical Defects, and Orthopedic Screws: A Phantom Study.

    PubMed

    Neubauer, Jakob; Benndorf, Matthias; Lang, Hannah; Lampert, Florian; Kemna, Lars; Konstantinidis, Lukas; Neubauer, Claudia; Reising, Kilian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Goerke, Sebastian M

    2015-08-01

    To compare the visualization of cortical fractures, cortical defects, and orthopedic screws in a dedicated extremity flat-panel computed tomography (FPCT) scanner and a multidetector computed tomography (MDCT) scanner.We used feet of European roe deer as phantoms for cortical fractures, cortical defects, and implanted orthopedic screws. FPCT and MDCT scans were performed with equivalent dose settings. Six observers rated the scans according to number of fragments, size of defects, size of defects opposite orthopedic screws, and the length of different screws. The image quality regarding depiction of the cortical bone was assessed. The gold standard (real number of fragments) was evaluated by autopsy.The correlation of reader assessment of fragments, cortical defects, and screws with the gold standard was similar for FPCT and MDCT. Three readers rated the subjective image quality of the MDCT to be higher, whereas the others showed no preferences.Although the image quality was rated higher in the MDCT than in the FPCT by 3 out of 6 observers, both modalities proved to be comparable regarding the visualization of cortical fractures, cortical defects, and orthopedic screws and of use to musculoskeletal radiology regarding fracture detection and postsurgical evaluation in our experimental setting. PMID:26252281

  18. Comparison of Multidetector Computed Tomography and Flat-Panel Computed Tomography Regarding Visualization of Cortical Fractures, Cortical Defects, and Orthopedic Screws

    PubMed Central

    Neubauer, Jakob; Benndorf, Matthias; Lang, Hannah; Lampert, Florian; Kemna, Lars; Konstantinidis, Lukas; Neubauer, Claudia; Reising, Kilian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Goerke, Sebastian M.

    2015-01-01

    Abstract To compare the visualization of cortical fractures, cortical defects, and orthopedic screws in a dedicated extremity flat-panel computed tomography (FPCT) scanner and a multidetector computed tomography (MDCT) scanner. We used feet of European roe deer as phantoms for cortical fractures, cortical defects, and implanted orthopedic screws. FPCT and MDCT scans were performed with equivalent dose settings. Six observers rated the scans according to number of fragments, size of defects, size of defects opposite orthopedic screws, and the length of different screws. The image quality regarding depiction of the cortical bone was assessed. The gold standard (real number of fragments) was evaluated by autopsy. The correlation of reader assessment of fragments, cortical defects, and screws with the gold standard was similar for FPCT and MDCT. Three readers rated the subjective image quality of the MDCT to be higher, whereas the others showed no preferences. Although the image quality was rated higher in the MDCT than in the FPCT by 3 out of 6 observers, both modalities proved to be comparable regarding the visualization of cortical fractures, cortical defects, and orthopedic screws and of use to musculoskeletal radiology regarding fracture detection and postsurgical evaluation in our experimental setting. PMID:26252281

  19. Advances in imaging protocols for cardiac MDCT: from 16- to 64-row multidetector computed tomography.

    PubMed

    Kopp, Andreas F; Heuschmid, Martin; Reimann, Anja; Kuettner, Axel; Beck, Thorsten; Burgstahler, Christoph; Brodoefel, Harald; Claussen, Claus D; Schroeder, Stephen

    2005-12-01

    Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the Western world. Since the majority of all invasive diagnostic coronary angiography procedures are not followed by therapeutic interventions, interest is growing in noninvasive technologies to diagnose and visualize CAD. The most promising of these is multislice spiral computed tomography (MSCT), which can visualize human coronary arteries in vivo noninvasively. Since 1999, this technique has improved rapidly, offering faster gantry rotation times and smaller voxel sizes. The image quality has become significantly more stable and MSCT has become a robust imaging modality. Beginning with 4-slice scanners in 1999, the latest scanner generation employs 64 slices. The present article summarizes the technical principles, image protocols and possible clinical applications of the current 64-row scanners. PMID:18637233

  20. Criteria for establishing shielding of multi-detector computed tomography (MDCT) rooms.

    PubMed

    Verdun, F R; Aroua, A; Baechler, S; Schmidt, S; Trueb, P R; Bochud, F O

    2010-01-01

    The aim of this work is to compare two methods used for determining the proper shielding of computed tomography (CT) rooms while considering recent technological advances in CT scanners. The approaches of the German Institute for Standardisation and the US National Council on Radiation Protection and Measurements were compared and a series of radiation measurements were performed in several CT rooms at the Lausanne University Hospital. The following three-step procedure is proposed for assuring sufficient shielding of rooms hosting new CT units with spiral mode acquisition and various X-ray beam collimation widths: (1) calculate the ambient equivalent dose for a representative average weekly dose length product at the position where shielding is required; (2) from the maximum permissible weekly dose at the location of interest, calculate the transmission factor F that must be taken to ensure proper shielding and (3) convert the transmission factor into a thickness of lead shielding. A similar approach could be adopted to use when designing shielding for fluoroscopy rooms, where the basic quantity would be the dose area product instead of the load of current (milliampere-minute). PMID:20215444

  1. Sex estimation based on scapula analysis in a Japanese population using multidetector computed tomography.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Yamaguchi, Rutsuko; Hashimoto, Mari; Hoshioka, Yumi; Iwase, Hirotaro

    2016-05-01

    Accurate sex estimation based on measurements of dimorphic dimensions in human unknown remains is important as the first step toward making individual identification. The purpose of this study was to assess the sexual dimorphism of the scapula and to quantify the accuracy of sex estimation in a contemporary Japanese forensic sample using scapular measurements based on three-dimensional (3D) computed tomographic (CT) images. A total of 218 cadavers (109 males, 109 females) that underwent postmortem CT and subsequent forensic autopsy were used. Ten scapular measurements were performed on 3D CT reconstructed images that extracted only bone data, and were analyzed using descriptive statistics and discriminant function analyses (DFA). All measurements were dimorphic in terms of sex differences. Univariate DFA provided sex classification accuracy rates of 75.7-91.3%. Stepwise DFA yielded sex prediction accuracy rates of 93.1-94.5%. In conclusion, the scapular measurements using 3D CT images of a contemporary Japanese population may be useful for the estimation of skeletal sex in the field of forensic anthropology. PMID:26965402

  2. Multidetector-row Computed Tomographic Angiography in the Planning of the Local Perforator Flaps

    PubMed Central

    Sliesarenko, Sergii V.

    2015-01-01

    Background: The perforator vessels are highly variable in number, localization types, hemodynamic specifications, and the anatomical interactions with other structures. For these reasons, the identification of the best perforator before the operation is very important for the choice of the main feed vessel and the design of the perforator flap. Methods: The authors retrospectively analyzed all cases in which multiple detector computed tomography (MDCT) with 3-dimensional (3D) image reconstruction was used in the preoperative planning in preparation for the reconstruction with local perforator flaps, which took place between July 2012 and December 2014 in the hospital. Results: A total of 24 people were examined and underwent operations with 26 reconstructions using local perforator flaps. All perforators, which were identified during the MDCT with 3D reconstruction examination, were located intraoperationally without any errors. Conclusions: The preoperative MDCT with 3D reconstruction investigations of the topographic anatomical specifics of the perforator vessel on which the formation of the flap feed pedicle is planned allow for the fast and precise identification of the perforation at the preoperative stage while minimizing the amount of injury caused to the perforator during the operation and decrease the operation time. PMID:26495229

  3. Distribution of Mitral Annular and Aortic Valve Calcium as Assessed by Unenhanced Multidetector Computed Tomography.

    PubMed

    Koshkelashvili, Nikoloz; Codolosa, Jose N; Goykhman, Igor; Romero-Corral, Abel; Pressman, Gregg S

    2015-12-15

    Aging is associated with calcium deposits in various cardiovascular structures, but patterns of calcium deposition, if any, are unknown. In search of such patterns, we performed quantitative assessment of mitral annular calcium (MAC) and aortic valve calcium (AVC) in a broad clinical sample. Templates were created from gated computed tomography (CT) scans depicting the aortic valve cusps and mitral annular segments in relation to surrounding structures. These were then applied to CT reconstructions from ungated, clinically indicated CT scans of 318 subjects, aged ≥65 years. Calcium location was assigned using the templates and quantified by the Agatston method. Mean age was 76 ± 7.3 years; 48% were men and 58% were white. Whites had higher prevalence (p = 0.03) and density of AVC than blacks (p = 0.02), and a trend toward increased MAC (p = 0.06). Prevalence of AVC was similar between men and women, but AVC scores were higher in men (p = 0.008); this difference was entirely accounted for by whites. Within the aortic valve, the left cusp was more frequently calcified than the others. MAC was most common in the posterior mitral annulus, especially its middle (P2) segment. For the anterior mitral annulus, the medial (A3) segment calcified most often. In conclusion, AVC is more common in whites than blacks, and more intense in men, but only in whites. Furthermore, calcium deposits in the mitral annulus and aortic valve favor certain locations. PMID:26517948

  4. Visual vs Fully Automatic Histogram-Based Assessment of Idiopathic Pulmonary Fibrosis (IPF) Progression Using Sequential Multidetector Computed Tomography (MDCT)

    PubMed Central

    Colombi, Davide; Dinkel, Julien; Weinheimer, Oliver; Obermayer, Berenike; Buzan, Teodora; Nabers, Diana; Bauer, Claudia; Oltmanns, Ute; Palmowski, Karin; Herth, Felix; Kauczor, Hans Ulrich; Sverzellati, Nicola

    2015-01-01

    Objectives To describe changes over time in extent of idiopathic pulmonary fibrosis (IPF) at multidetector computed tomography (MDCT) assessed by semi-quantitative visual scores (VSs) and fully automatic histogram-based quantitative evaluation and to test the relationship between these two methods of quantification. Methods Forty IPF patients (median age: 70 y, interquartile: 62-75 years; M:F, 33:7) that underwent 2 MDCT at different time points with a median interval of 13 months (interquartile: 10-17 months) were retrospectively evaluated. In-house software YACTA quantified automatically lung density histogram (10th-90th percentile in 5th percentile steps). Longitudinal changes in VSs and in the percentiles of attenuation histogram were obtained in 20 untreated patients and 20 patients treated with pirfenidone. Pearson correlation analysis was used to test the relationship between VSs and selected percentiles. Results In follow-up MDCT, visual overall extent of parenchymal abnormalities (OE) increased in median by 5 %/year (interquartile: 0 %/y; +11 %/y). Substantial difference was found between treated and untreated patients in HU changes of the 40th and of the 80th percentiles of density histogram. Correlation analysis between VSs and selected percentiles showed higher correlation between the changes (Δ) in OE and Δ 40th percentile (r=0.69; p<0.001) as compared to Δ 80th percentile (r=0.58; p<0.001); closer correlation was found between Δ ground-glass extent and Δ 40th percentile (r=0.66, p<0.001) as compared to Δ 80th percentile (r=0.47, p=0.002), while the Δ reticulations correlated better with the Δ 80th percentile (r=0.56, p<0.001) in comparison to Δ 40th percentile (r=0.43, p=0.003). Conclusions There is a relevant and fully automatically measurable difference at MDCT in VSs and in histogram analysis at one year follow-up of IPF patients, whether treated or untreated: Δ 40th percentile might reflect the change in overall extent of lung

  5. The role of 64-slice multi-detector computed tomography in the detection of subclinical atherosclerosis of the coronary artery.

    PubMed

    Jeong, Hae Chang; Ahn, Youngkeun; Ko, Jum Suk; Lee, Min Goo; Sim, Doo Sun; Park, Keun Ho; Yoon, Nam Sik; Youn, Hyun Ju; Hong, Young Joon; Kim, Kye Hun; Park, Hyung Wook; Kim, Ju Han; Kim, Yun-Hyeon; Jeong, Myung Ho; Cho, Jeong Gwan; Park, Jong Chun; Kang, Jung Chaee

    2010-12-01

    Multi-detector computed tomography (MDCT) has been used for detecting or excluding coronary atherosclerotic stenosis in symptomatic patients. However, the role of MDCT for routine medical examination in asymptomatic, high-risk patients has not been established. We therefore conducted the present study to test the hypothesis that MDCT could be a valuable method for detecting subclinical coronary artery stenosis in asymptomatic patients. An observational, retrospective, single-centre study was conducted with a cohort of 1,529 patients (mean age, 56.4 ± 8.3 years; 1,353 males) who had undergone MDCT as part of their general medical checkups from November 2005 to April 2008. The patients who had a past history of coronary artery disease, typical chest pain, or evidence of myocardial ischemia were excluded. During clinical follow up of these patients, the incidence of subclinical coronary stenosis and the usefulness of MDCT for routine medical examination in asymptomatic patients were investigated. Of the 1,529 enrolled patients, 42.3% had hypertension, 13.5% had diabetes mellitus, 7.7% had hyperlipidemia, and 40.4% were current smokers. Abnormal MDCT findings were noted in 560 (36.6%) patients, who were classified into two groups. One group had the presence coronary calcium with a luminal diameter stenosis of the coronary artery of <50% (n = 508, 33.2%). These patients were treated with medication or clinical follow-up. The other group had a luminal diameter stenosis of the coronary artery of ≥50% with the presence or absence of coronary calcium (n = 52, 3.4%). These patients underwent a conventional coronary angiogram and intravascular ultrasound. A total of 29 of the 1,529 patients (1.9%) presented with insignificant stenosis or myocardial bridge, and 23 patients (1.5%) presented with significant stenosis. The patients with significant stenosis underwent percutaneous coronary intervention (PCI) with stent implantation. Major adverse cardiac events occurred

  6. Spinopelvic dissociation: multidetector computed tomographic evaluation of fracture patterns and associated injuries at a single level 1 trauma center.

    PubMed

    Gupta, Pushpender; Barnwell, Jonathan C; Lenchik, Leon; Wuertzer, Scott D; Miller, Anna N

    2016-06-01

    The objective of the present study is to evaluate multidetector computed tomographic (MDCT) fracture patterns and associated injuries in patients with spinopelvic dissociation (SPD). Our institutional trauma registry database was reviewed from Jan. 1, 2006, to Sept. 30, 2012, specifically evaluating patients with sacral fractures. MDCT scans of patients with sacral fractures were reviewed to determine the presence of SPD. SPD cases were characterized into the following fracture patterns: U-shaped, Y-shaped, T-shaped, H-shaped, and burst. The following MDCT features were recorded: level of the horizontal fracture, location of vertical fracture, kyphosis between major fracture fragments, displacement of fracture fragment, narrowing of central spinal canal, narrowing of neural foramina, and extension into sacroiliac joints. Quantitative evaluation of the sacral fractures was performed in accordance with the consensus statement by the Spine Trauma Study Group. Medical records were reviewed to determine associated pelvic and non-pelvic fractures, bladder and bowel injuries, nerve injuries, and type of surgical intervention. Twenty-one patients had SPD, of whom 13 were men and eight were women. Mean age was 41.8 years (range 18.8 to 87.7). Five fractures (24 %) were U-shaped, six (29 %) H-shaped, four (19 %) Y-shaped, and six (29 %) burst. Nine patients (43 %) had central canal narrowing, and 19 (90 %) had neural foramina narrowing. Eleven patients (52 %) had kyphotic angulation between major fracture fragments, and seven patients (33 %) had either anterior (24 %) or posterior (10 %) displacement of the proximal fracture fragment. Fourteen patients (67 %) had associated pelvic fractures, and 20 (95 %) had associated non-pelvic fractures. Two patients (10 %) had associated urethral injuries, and one (5 %) had an associated colon injury. Seven patients (33 %) had associated nerve injuries. Six patients (29 %) had surgical fixation while 15 (71 %) were

  7. Role of 16-multidetector computed tomography in the assessment of coronary artery stenoses: A prospective study of consecutive patients

    PubMed Central

    Postel, Thomas; Frick, Matthias; Feuchtner, Gudrun; Alber, Hannes; Zwick, Ralf; Suessenbacher, Alois; Mallouhi, Ammar; Friedrich, Guy; Pachinger, Otmar; Nedden, Dieter Zur; Weidinger, Franz

    2007-01-01

    BACKGROUND Recent studies have demonstrated a high sensitivity (S) of 16-multidetector computed tomography (16-MDCT) for the detection of significant coronary artery stenoses. Whether these results are applicable to clinical practice is unclear. Therefore, the aim of the present study was to compare 16-MDCT angiography with conventional coronary angiography (CCA) for the detection of significant coronary artery stenoses in a consecutive series of patients. METHOD A total of 93 consecutive patients (mean [± SD] age 59±9 years), in whom CCA was performed for stable angina pectoris, underwent 16-MDCT angiography (16×0.75 mm, table feed 6.5 mm/s, rotation time 0.42 s; Sensation 16, Siemens Medical Solutions, Germany) the day before performing CCA. Patients with diabetes mellitus, serum creatinine level higher than 132.6 μmol/L and/or acute coronary syndromes were excluded. Two observers blinded to CCA results evaluated MDCT angiograms according to standard criteria. Segment-based (13 segments per patient) and patient-based (at least one stenosis greater than 50% lumen diameter reduction) analyses were performed. RESULTS A total of 1209 segments were analyzed. Of these segments, 173 (14%) were excluded due to poor image quality or massive calcification. In 86 segments, CCA revealed significant coronary artery stenosis (greater than 50% diameter reduction). However, 16-MDCT detected only 47 of these, resulting in a S of 55% and a specificity (SP) of 97% (positive predictive value 64%; negative predictive value 96%). On a patient-based analysis, the S increased to 89%, whereas the SP still remained high (87%). CONCLUSION In this relatively large consecutive cohort, S for the detection of significant coronary artery stenoses was moderate on a segment-based analysis but increased on a patient-based analysis using 16-MDCT. In contrast, SP was high in both analyses, supporting the use of 16-MDCT for the exclusion of significant coronary artery stenoses. Further

  8. Relevant incidental findings at abdominal multi-detector contrast-enhanced computed tomography: A collateral screening?

    PubMed Central

    Sconfienza, Luca Maria; Mauri, Giovanni; Muzzupappa, Claudia; Poloni, Alessandro; Bandirali, Michele; Esseridou, Anastassia; Tritella, Stefania; Secchi, Francesco; Di Leo, Giovanni; Sardanelli, Francesco

    2015-01-01

    AIM: To investigate the prevalence of relevant incidental findings (RIFs) detected during routine abdominal contrast-enhanced computed tomography (CeCT). METHODS: We retrospectively evaluated the reports of a consecutive series of abdominal CeCT studies performed between January and May 2013. For each report, patients’ age and sex, admission as inpatient or outpatient, clinical suspicion as indicated by the requesting physician, availability of a previous abdominal examination, and name of the reporting radiologist were recorded. Based on the clinical suspicion, the presence and features of any RIFs (if needing additional workup) was noted. RESULTS: One thousand forty abdominal CeCT were performed in 949 patients (528 males, mean age 66 ± 14 years). No significant difference was found between inpatients and outpatients age and sex distribution (P > 0.472). RIFs were found in 195/1040 (18.8%) CeCT [inpatients = 108/470 (23.0%); outpatients = 87/570 (15.2%); P = 0.002]. RIFs were found in 30/440 (6.8%) CeCT with a previous exam and in 165/600 (27.5%) without a previous exam (P < 0.001). Radiologists’ distribution between inpatients or outpatients was significantly different (P < 0.001). RIFs prevalence increased with aging, except for a peak in 40-49 year group. Most involved organs were kidneys, gallbladder, and lungs. CONCLUSION: A RIF is detected in 1/5 patients undergoing abdominal CeCT. Risk of overdiagnosis should be taken into account. PMID:26516432

  9. Role of 64 slice multidetector computed tomography and angiography to establish relationship between tumor size, aneurysm formation and spontaneous rupture of renal angiomyolipomas: Single center experience

    PubMed Central

    Gandhi, Shruti P.; Pal, Bipin Chandra; Patel, Kajal N.; Sutariya, Harsh; Trivedi, Hargovind L.

    2016-01-01

    Objective: To evaluate the role of computed tomography (CT) angiography using 64 slice multidetector CT scan to establish relationships among tumor size, aneurysm formation, and spontaneous rupture of renal angiomyolipomas (AML). Materials and Methods: Total 27 patients were diagnosed as having renal angiomyolipoma (AML) at institute of kidney disease and research center from June 2008 to June 2015. All patients with renal AML underwent contrast-enhanced CT (CECT) with CT angiography with 64 slice multidetector CT scan. Results: Total 34 kidneys were found to be affected by AML. Out of which 6 AML were ruptured and remaining 28 were unruptured. If tumor size of 4 cm or larger is used as predictor of rupture; sensitivity 20%, specificity 89%, positive predictive value 83.3%, and negative predictive value 28.5%; and If aneurysm size >5 mm is used as predictor of rupture; sensitivity 75%, specificity 90%, positive predictive value 50%, and negative predictive value 96.4% was found. Conclusion: Tumor size, aneurysm size and tumor multiplicity cannot use as a predictor of spontaneous rupture of the tumor. PMID:27141187

  10. Dataset of calcified plaque condition in the stenotic coronary artery lesion obtained using multidetector computed tomography to indicate the addition of rotational atherectomy during percutaneous coronary intervention.

    PubMed

    Akutsu, Yasushi; Hamazaki, Yuji; Sekimoto, Teruo; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Suyama, Jumpei; Gokan, Takehiko; Sakai, Koshiro; Kosaki, Ryota; Yokota, Hiroyuki; Tsujita, Hiroaki; Tsukamoto, Shigeto; Sakurai, Masayuki; Sambe, Takehiko; Oguchi, Katsuji; Uchida, Naoki; Kobayashi, Shinichi; Aoki, Atsushi; Kobayashi, Youichi

    2016-06-01

    Our data shows the regional coronary artery calcium scores (lesion CAC) on multidetector computed tomography (MDCT) and the cross-section imaging on MDCT angiography (CTA) in the target lesion of the patients with stable angina pectoris who were scheduled for percutaneous coronary intervention (PCI). CAC and CTA data were measured using a 128-slice scanner (Somatom Definition AS+; Siemens Medical Solutions, Forchheim, Germany) before PCI. CAC was measured in a non-contrast-enhanced scan and was quantified using the Calcium Score module of SYNAPSE VINCENT software (Fujifilm Co. Tokyo, Japan) and expressed in Agatston units. CTA were then continued with a contrast-enhanced ECG gating to measure the severity of the calcified plaque condition. We present that both CAC and CTA data are used as a benchmark to consider the addition of rotational atherectomy during PCI to severely calcified plaque lesions. PMID:26977441

  11. Imaging of extralobar pulmonary sequestration in a patient with tetralogy of Fallot with pulmonary atresia, ventricular septal defect and multiple aorto-pulmonary collateral arteries with multidetector computed tomography.

    PubMed

    Greil, Gerald F; Schoebinger, Max; Kuettner, Axel; Schaefer, Jürgen F; Hofbeck, Michael; Claussen, Claus D; Meinzer, Hans-Peter; Sieverding, Ludger

    2008-01-01

    Complex pulmonary vascular blood supply is common in patients with tetralogy of Fallot with pulmonary atresia, major systemic to pulmonary collateral arteries and hypoplastic or deficient central pulmonary arteries. An extralobar lung sequestration, which has not been described previously in these patients, was imaged in a 6-week-old infant with multidetector computed tomography with sub-millimeter resolution. Arterial and venous vessels were analyzed using three-dimensional vascular exploration tools and results were confirmed with cardiac catheterization. PMID:18715464

  12. The Role of Multidetector Computed Tomography in the Early Diagnosis of Invasive Pulmonary Aspergillosis in Patients with Febrile Neutropenia Undergoing Hematopoietic Stem Cell Transplantation

    PubMed Central

    Çiledağ, Nazan; Arda, Kemal; Arıbaş, Bilgin Kadri; Tekgündüz, Ali Irfan Emre; Altuntaş, Fevzi

    2012-01-01

    Objective: To evaluate vessel involvement and the role of multidetector computed tomography (MDCT) in the earlydiagnosis of invasive pulmonary aspergillosis (IPA) in patients with febrile neutropenia and antibiotic-resistant feverundergoing autologous bone morrow transplantation. Material and Methods: In all, 74 pulmonary MDCT examinations in 37 consecutive hematopoietic stem celltransplantation patients with febrile neutropenia and clinically suspected IPA were retrospectively evaluated. Results: Diagnosis of IPA was based on Fungal Infections Cooperative Group, and National Institute of Allergy andInfectious Diseases Mycoses Study Consensus Group criteria. In all, 0, 14, and 11 patients were diagnosed as proven,probable, and possible IPA, respectively. Among the 25 patients accepted as probable and possible IPA, all had pulmonaryMDCT findings consistent with IPA. The remaining 12 patients were accepted as having fever of unknown origin (FUO)and had patent vessels based on MDCT findings.In the patients with probable and possible IPA, 72 focal pulmonary lesions were observed; in 41 of the 72 (57%) lesionsvascular occlusion was noted and the CT halo sign was observed in 25 of these 41 (61%) lesions. Resolution of feveroccurred following antifungal therapy in 19 (76%) of the 25 patients with probable and possible IPA. In all, 6 (25%)of the patients diagnosed as IPA died during follow-up. Transplant-related mortality 100 d post transplant in patientswith IPA and FUO was 24% and 0%, respectively. Conclusion: In conclusion, MDCT has a potential role in the early diagnosis of IPA via detection of vessel occlusion. PMID:24744620

  13. State of the Art. A structural and functional assessment of the lung via multidetector-row computed tomography: phenotyping chronic obstructive pulmonary disease.

    PubMed

    Hoffman, Eric A; Simon, Brett A; McLennan, Geoffrey

    2006-08-01

    With advances in multidetector-row computed tomography (MDCT), it is now possible to image the lung in 10 s or less and accurately extract the lungs, lobes, and airway tree to the fifth- through seventh-generation bronchi and to regionally characterize lung density, texture, ventilation, and perfusion. These methods are now being used to phenotype the lung in health and disease and to gain insights into the etiology of pathologic processes. This article outlines the application of these methodologies with specific emphasis on chronic obstructive pulmonary disease. We demonstrate the use of our methods for assessing regional ventilation and perfusion and demonstrate early data that show, in a sheep model, a regionally intact hypoxic pulmonary vasoconstrictor (HPV) response with an apparent inhibition of HPV regionally in the presence of inflammation. We present the hypothesis that, in subjects with pulmonary emphysema, one major contributing factor leading to parenchymal destruction is the lack of a regional blunting of HPV when the regional hypoxia is related to regional inflammatory events (bronchiolitis or alveolar flooding). If maintaining adequate blood flow to inflamed lung regions is critical to the nondestructive resolution of inflammatory events, the pathologic condition whereby HPV is sustained in regions of inflammation would likely have its greatest effect in the lung apices where blood flow is already reduced in the upright body posture. PMID:16921136

  14. Detection of Cement Leakage After Vertebroplasty with a Non-Flat-Panel Angio Unit Compared to Multidetector Computed Tomography - An Ex Vivo Study

    SciTech Connect

    Baumann, Clemens Fuchs, Heiko; Westphalen, Kerstin; Hierholzer, Johannes

    2008-11-15

    The purpose of this study was to investigate the detection of cement leakages after vertebroplasty using angiographic computed tomography (ACT) in a non-flat-panel angio unit compared to multidetector computed tomography (MDCT). Vertebroplasty was performed in 19 of 33 cadaver vertebrae (23 thoracic and 10 lumbar segments). In the angio suite, ACT (190{sup o}; 1.5{sup o} per image) was performed to obtain volumetric data. Another volumetric data set of the specimen was obtained by MDCT using a standard algorithm. Nine multiplanar reconstructions in standardized axial, coronal, and sagittal planes of every vertebra were generated from both data sets. Images were evaluated on the basis of a nominal scale with 18 criteria, comprising osseous properties (e.g., integrity of the end plate) and cement distribution (e.g., presence of intraspinal cement). MDCT images were regarded as gold standard and analyzed by two readers in a consensus mode. Rotational acquisitions were analyzed by six blinded readers. Results were correlated with the gold standard using Cohen's {kappa}-coefficient analysis. Furthermore, interobserver variability was calculated. Correlation with the gold standard ranged from no correlation (osseous margins of the neuroforamen, {kappa} = 0.008) to intermediate (trace of vertebroplasty canula; {kappa} = 0.615) for criteria referring to osseous morphology. However, there was an excellent correlation for those criteria referring to cement distribution, with {kappa} values ranging from 0.948 (paravertebral cement distribution) to 0.972 (intraspinal cement distribution). With a minimum of {kappa} = 0.768 ('good correlation') and a maximum of {kappa} = 0.91 ('excellent'), interobserver variability was low. In conclusion, ACT in an angio suite without a flat-panel detector depicts a cement leakage after vertebroplasty as well as MDCT. However, the method does not provide sufficient depiction of osseous morphology.

  15. Comparison of enhancement and image quality: different iodine concentrations for liver on 128-slice multidetector computed tomography in the same chronic liver disease patients

    PubMed Central

    Jo, Byoung Goo; Song, Yun Gyu; Shim, Sang Goon; Kim, Young Wook

    2016-01-01

    Background/Aims: The objective of this study was to compare the degree of hepatic enhancement and image quality using contrast media of different iodine concentrations with the same iodine dose. Methods: From July 2011 to June 2013, 50 patients with chronic liver disease who underwent baseline and follow-up 128-slice multidetector computed tomography(MDCT) using contrast media with 350 mg I/mL (group A) and 400 mg I/mL (group B) iodine concentrations were included in this prospective study. The patients were randomly allocated to one of two protocols: 350 mg I/mL initially and then 400 mg I/mL; and 400 mg I/mL initially and then 350 mg I/mL. The bolus tracking technique was used to initiate the arterial phase scan. The computed tomography values of hepatic parenchyma, abdominal aorta and portal vein were measured. The degrees of hepatic and vascular enhancement were rated on a 4-point scale for qualitative assessment. The paired Student t test was used to compare outcome variables. Results: The mean hepatic enhancement was significantly higher in group B than in group A during the portal (p = 0.025) and equilibrium phases (p = 0.021). In all phases, group B had significantly higher mean liver-to-aorta contrast (p < 0.05) and mean visual scores for hepatic and vascular enhancement (p < 0.001). Conclusions: This study showed that a higher iodine concentration (400 mg I/mL) in contrast media was more effective at improving hepatic enhancement in portal and equilibrium phase images and overall image quality using 128-slice MDCT in chronic liver disease patients. PMID:26701234

  16. Anthropometric Assessment of Neck Adipose Tissue and Airway Volume Using Multidetector Computed Tomography: An Imaging Approach and Association With Overall Mortality.

    PubMed

    Maresky, Hillel S; Sharfman, Zachary; Ziv-Baran, Tomer; Gomori, J M; Copel, Laurian; Tal, Sigal

    2015-11-01

    Neck adiposity tissue volume (NATV) accumulation is an indicator for metabolic syndrome and cardiovascular disease (CVD). Neck circumference is a poor measure of NATV, and a quantifier for this entity has not yet been established. To evaluate volumetric quantification by multidetector computed tomography (MDCT) as a reproducible anthropometric tool to measure NATV and airway volume (AWV). A total of 519 patients, including a subset of 70 random patients who underwent head and neck CT scanning in our hospital within 1 year (2013), were studied. Included patients were all those undergoing nonenhanced CT (NECT) or CT angiography (CTA). Neck cross-sectional areas (NCSA) were measured at 2 separate levels of the neck, and 3D postprocessing tissue reconstruction was performed, and NATV and AWVs were quantified volumetrically for all patients within the year. The average NCSA at the level of the soft palate and thyroid cartilage was 22,579 and 14,500 mm, respectively. NATV when compared to the upper and lower levels of NCSA showed correlations of 0.64 and 0.79, respectively (P < 0.001). Interobserver analysis showed mean deviations of 0.46% and 0.32% for NATV and AWV, respectively. A strong correlation between NATV and body mass index (BMI) was found (r = 0.658, P < 0.001), and the top quartile of NATV:AWV patients (out of 519 patients) displayed a statistically significant mortality rate during 670 days of follow-up (d = 7.5%, P = 0.032). After adjustment for age and gender, the association between NATV:AWV and mortality was close to significant (P = 0.072). Volumetric quantification of NATV and AWV is a reproducible and prognostic anthropometric tool, as a high NATV:AWV demonstrated a significant risk factor for mortality; future research may further advance our understanding of this phenomenon. PMID:26559286

  17. Perforated duodenal ulcer presenting with a subphrenic abscess revealed by plain abdominal X-ray films and confirmed by multi-detector computed tomography: a case report

    PubMed Central

    2013-01-01

    Introduction Peptic ulcer disease is still the major cause of gastrointestinal perforation despite major improvements in both diagnostic and therapeutic strategies. While the diagnosis of a perforated ulcer is straightforward in typical cases, its clinical onset may be subtle because of comorbidities and/or concurrent therapies. Case presentation We report the case of a 53-year-old Caucasian man with a history of chronic myeloid leukemia on maintenance therapy (100mg/day) with imatinib who was found to have a subphrenic abscess resulting from a perforated duodenal ulcer that had been clinically overlooked. Our patient was febrile (38.5°C) with abdominal tenderness and hypoactive bowel sounds. On the abdominal plain X-ray films, a right subphrenic abscess could be seen. On contrast-enhanced multi-detector computed tomography, a huge air-fluid collection extending from the subphrenic to the subhepatic anterior space was observed. After oral administration of 500cm3 of 3 percent diluted diatrizoate meglumine, an extraluminal leakage of the water-soluble iodinated contrast media could then be appreciated as a result of a perforated duodenal ulcer. During surgery, the abscess was drained and extensive adhesiolysis had to be performed to expose the duodenal bulb where the ulcer was first identified by methylene blue administration and then sutured. Conclusions While subphrenic abscesses are well known complications of perforated gastric or duodenal ulcers, they have nowadays become rare thanks to advances in both diagnostic and therapeutic strategies for peptic ulcer disease. However, when peptic ulcer disease is not clinically suspected, the contribution of imaging may be substantial. PMID:24215711

  18. Morphometric Evaluation of Bony Nasolacrimal Canal in a Caucasian Population with Primary Acquired Nasolacrimal Duct Obstruction: A Multidetector Computed Tomography Study

    PubMed Central

    Yazici, Alper; Yanik, Bahar; Yazici, Hasmet; Demirpolat, Gulen

    2016-01-01

    Objective The bony nasolacrimal duct (BNLD) morphology as a contributory factor in primary acquired nasolacrimal duct obstruction (PANDO) is still controversial. The objectives of this study were to evaluate the morphometric differences of BNLDs in unilateral PANDO patients between PANDO and non-PANDO sides, as compared with the control group using multidetector computed tomography (CT). Materials and Methods Bilateral BNLDs in 39 unilateral PANDO patients and 36 control subjects were retrospectively reviewed. CT images with 0.5-mm thickness were obtained with a 64-slice scanner. The length, volume, coronal orientation type, sagittal orientation angle of BNLD, and relative lacrimal sac-BNLD angle were assessed. The entrance, minimum and distal end transverse diameters (TD) of BNLD was investigated. Results The mean minimum and distal end BNLD TDs measurements were significantly narrower in PANDO patients, both in PANDO and non-PANDO sides, as compared with the control group (p < 0.001 and p = 0.040, respectively); however, there were no significant differences between PANDO and non-PANDO sides within PANDO patients. The length, entrance TD, volume, coronal orientation type, sagittal orientation angle of BNLD, and relative lacrimal sac-BNLD angle were not significantly different between PANDO patients and control subjects, as well as between PANDO and non-PANDO sides within PANDO patients. Conclusion The narrow mean minimum and distal end BNLD TD in PANDO patients, in both PANDO and non-PANDO sides, may be associated with PANDO development. The lack of difference between PANDO and non-PANDO sides within PANDO patients and some overlap between PANDO patients and control subjects suggest that narrow BNLD is not the sole factor. PMID:26957913

  19. Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

    SciTech Connect

    Fanelli, Fabrizio Bezzi, Mario; Bruni, Antonio; Corona, Mario; Boatta, Emanuele; Lucatelli, Pierleone; Passariello, Roberto

    2011-02-15

    We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound-color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

  20. Imaging pitfalls, normal anatomy, and anatomical variants that can simulate disease on cardiac imaging as demonstrated on multidetector computed tomography

    PubMed Central

    White, Charles S

    2015-01-01

    Advances in computed tomography have led to continuous improvement in cardiac imaging. Dedicated postprocessing capabilities, faster scan times, and cardiac gating methods reveal details of normal cardiac anatomy and anatomic variants that can mimic pathologic conditions. This article will review normal cardiac anatomy and variants that can mimic disease. Radiologists should be familiar with normal cardiac anatomy and anatomic variants to avoid misinterpretation of normal findings for pathologic processes. PMID:25610617

  1. Improved vessel morphology measurements in contrast-enhanced multi-detector computed tomography coronary angiography with non-linear post-processing.

    PubMed

    Ferencik, Maros; Lisauskas, Jennifer B; Cury, Ricardo C; Hoffmann, Udo; Abbara, Suhny; Achenbach, Stephan; Karl, W Clem; Brady, Thomas J; Chan, Raymond C

    2006-03-01

    Multi-detector computed tomography (MDCT) permits detection of coronary plaque. However, noise and blurring impair accuracy and precision of plaque measurements. The aim of the study was to evaluate MDCT post-processing based on non-linear image deblurring and edge-preserving noise suppression for measurements of plaque size. Contrast-enhanced MDCT coronary angiography was performed in four subjects (mean age 55 +/- 5 years, mean heart rate 54 +/- 5 bpm) using a 16-slice scanner (Siemens Sensation 16, collimation 16 x 0.75 mm, gantry rotation 420 ms, tube voltage 120 kV, tube current 550 mAs, 80 mL of contrast). Intravascular ultrasound (IVUS; 40 MHz probe) was performed in one vessel in each patient and served as a reference standard. MDCT vessel cross-sectional images (1 mm thickness) were created perpendicular to centerline and aligned with corresponding IVUS images. MDCT images were processed using a deblurring and edge-preserving noise suppression algorithm. Then, three independent blinded observers segmented lumen and outer vessel boundaries in each modality to obtain vessel cross-sectional area and wall area in the unprocessed MDCT cross-sections, post-processed MDCT cross-sections and corresponding IVUS. The wall area measurement difference for unprocessed and post-processed MDCT images relative to IVUS was 0.4 +/- 3.8 mm2 and -0.2 +/- 2.2 mm2 (p < 0.05), respectively. Similarly, Bland-Altman analysis of vessel cross-sectional area from unprocessed and post-processed MDCT images relative to IVUS showed a measurement difference of 1.0 +/- 4.4 and 0.6 +/- 4.8 mm2, respectively. In conclusion, MDCT permitted accurate in vivo measurement of wall area and vessel cross-sectional area as compared to IVUS. Post-processing to reduce blurring and noise reduced variability of wall area measurements and reduced measurement bias for both wall area and vessel cross-sectional area. PMID:16442768

  2. Magnetic resonance imaging and multi-detector computed tomography assessment of extracellular compartment in ischemic and non-ischemic myocardial pathologies

    PubMed Central

    Saeed, Maythem; Hetts, Steven W; Jablonowski, Robert; Wilson, Mark W

    2014-01-01

    Myocardial pathologies are major causes of morbidity and mortality worldwide. Early detection of loss of cellular integrity and expansion in extracellular volume (ECV) in myocardium is critical to initiate effective treatment. The three compartments in healthy myocardium are: intravascular (approximately 10% of tissue volume), interstitium (approximately 15%) and intracellular (approximately 75%). Myocardial cells, fibroblasts and vascular endothelial/smooth muscle cells represent intracellular compartment and the main proteins in the interstitium are types I/III collagens. Microscopic studies have shown that expansion of ECV is an important feature of diffuse physiologic fibrosis (e.g., aging and obesity) and pathologic fibrosis [heart failure, aortic valve disease, hypertrophic cardiomyopathy, myocarditis, dilated cardiomyopathy, amyloidosis, congenital heart disease, aortic stenosis, restrictive cardiomyopathy (hypereosinophilic and idiopathic types), arrythmogenic right ventricular dysplasia and hypertension]. This review addresses recent advances in measuring of ECV in ischemic and non-ischemic myocardial pathologies. Magnetic resonance imaging (MRI) has the ability to characterize tissue proton relaxation times (T1, T2, and T2*). Proton relaxation times reflect the physical and chemical environments of water protons in myocardium. Delayed contrast enhanced-MRI (DE-MRI) and multi-detector computed tomography (DE-MDCT) demonstrated hyper-enhanced infarct, hypo-enhanced microvascular obstruction zone and moderately enhanced peri-infarct zone, but are limited for visualizing diffuse fibrosis and patchy microinfarct despite the increase in ECV. ECV can be measured on equilibrium contrast enhanced MRI/MDCT and MRI longitudinal relaxation time mapping. Equilibrium contrast enhanced MRI/MDCT and MRI T1 mapping is currently used, but at a lower scale, as an alternative to invasive sub-endomyocardial biopsies to eliminate the need for anesthesia, coronary

  3. Value of two-phase dynamic multidetector computed tomography in differential diagnosis of post-inflammatory strictures from esophageal cancer

    PubMed Central

    Karmazanovsky, Grigory G; Buryakina, Svetlana A; Kondratiev, Evgeny V; Yang, Qin; Ruchkin, Dmitry V; Kalinin, Dmitry V

    2015-01-01

    AIM: To characterize the computed tomography (CT) findings in patients with post-inflammatory esophageal strictures (corrosive and peptic) and reveal the optimal scanning phase protocols for distinguishing post-inflammatory esophageal stricture and esophageal cancer. METHODS: Sixty-five patients with esophageal strictures of different etiology were included in this study: 24 patients with 27 histopathologically confirmed corrosive strictures, 10 patients with 12 peptic strictures and 31 patients with esophageal cancer were evaluated with a two-phase dynamic contrast-enhanced MDCT. Arterial and venous phases at 10 and 35 s after the attenuation of 200 HU were obtained at the descending aorta, with a delayed phase at 6-8 min after the start of injection of contrast media. For qualitative analysis, CT scans of benign strictures were reviewed for the presence/absence of the following features: “target sign”, luminal mass, homogeneity of contrast medium uptake, concentric wall thickening, conically shaped suprastenotic dilatation, smooth boundaries of stenosis and smooth mucous membrane at the transition to stenosis, which were compared with a control group of 31 patients who had esophageal cancer. The quantitative analysis included densitometric parameter acquisition using regions-of-interest measurement of the zone of stenosis and normal esophageal wall and the difference between those measurements (ΔCT) at all phases of bolus contrast enhancement. Esophageal wall thickening, length of esophageal wall thickening and size of the regional lymph nodes were also evaluated. RESULTS: The presence of a concentric esophageal wall, conically shaped suprastenotic dilatation, smooth upper and lower boundaries, “target sign” and smooth mucous membrane at the transition to stenosis were suggestive of a benign cause, with sensitivities of 92.31%, 87.17%, 94.87%, 76.92% and 82.05%, respectively, and specificities of 70.96%, 89.66%, 80.65%, 96.77% and 93.55%, respectively

  4. Role of multidetector computed tomography in the diagnosis and management of patients attending the rapid access chest pain clinic, The Scottish computed tomography of the heart (SCOT-HEART) trial: study protocol for randomized controlled trial

    PubMed Central

    2012-01-01

    Background Rapid access chest pain clinics have facilitated the early diagnosis and treatment of patients with coronary heart disease and angina. Despite this important service provision, coronary heart disease continues to be under-diagnosed and many patients are left untreated and at risk. Recent advances in imaging technology have now led to the widespread use of noninvasive computed tomography, which can be used to measure coronary artery calcium scores and perform coronary angiography in one examination. However, this technology has not been robustly evaluated in its application to the clinic. Methods/design The SCOT-HEART study is an open parallel group prospective multicentre randomized controlled trial of 4,138 patients attending the rapid access chest pain clinic for evaluation of suspected cardiac chest pain. Following clinical consultation, participants will be approached and randomized 1:1 to receive standard care or standard care plus ≥64-multidetector computed tomography coronary angiography and coronary calcium score. Randomization will be conducted using a web-based system to ensure allocation concealment and will incorporate minimization. The primary endpoint of the study will be the proportion of patients diagnosed with angina pectoris secondary to coronary heart disease at 6 weeks. Secondary endpoints will include the assessment of subsequent symptoms, diagnosis, investigation and treatment. In addition, long-term health outcomes, safety endpoints, such as radiation dose, and health economic endpoints will be assessed. Assuming a clinic rate of 27.0% for the diagnosis of angina pectoris due to coronary heart disease, we will need to recruit 2,069 patients per group to detect an absolute increase of 4.0% in the rate of diagnosis at 80% power and a two-sided P value of 0.05. The SCOT-HEART study is currently recruiting participants and expects to report in 2014. Discussion This is the first study to look at the implementation of computed

  5. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 2: Appendixes A-K

    NASA Technical Reports Server (NTRS)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The appendices A-K to the user's manual for the rocket combustor interactive design (ROCCID) computer program are presented. This includes installation instructions, flow charts, subroutine model documentation, and sample output files. The ROCCID program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can be easily added. The analysis models in ROCCID can account for the influences of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  6. Uncommon Complex Anomaly of Inferior Vena Cava and Left Iliac Vein Demonstrated by Multidetector-Row CT Angiography

    PubMed Central

    Ogul, Hayri; Yuce, Ihsan; Yalcin, Ahmet; Karaca, Leyla; Okur, Aylin; Kantarci, Mecit

    2014-01-01

    Retroperitoneal venous anomalies have clinical importance in retroperitoneal and pelvic surgery. Multidetector-row computed tomography (CT) angiography is an important imaging method to be preferred in evaluating vascular structures in this locality. We describe a complex retroperitoneal venous anomaly with a multidetector-row CT angiography. PMID:25437601

  7. Multidetector CT of blunt abdominal trauma.

    PubMed

    Soto, Jorge A; Anderson, Stephan W

    2012-12-01

    The morbidity, mortality, and economic costs resulting from trauma in general, and blunt abdominal trauma in particular, are substantial. The "panscan" (computed tomographic [CT] examination of the head, neck, chest, abdomen, and pelvis) has become an essential element in the early evaluation and decision-making algorithm for hemodynamically stable patients who sustained abdominal trauma. CT has virtually replaced diagnostic peritoneal lavage for the detection of important injuries. Over the past decade, substantial hardware and software developments in CT technology, especially the introduction and refinement of multidetector scanners, have expanded the versatility of CT for examination of the polytrauma patient in multiple facets: higher spatial resolution, faster image acquisition and reconstruction, and improved patient safety (optimization of radiation delivery methods). In this article, the authors review the elements of multidetector CT technique that are currently relevant for evaluating blunt abdominal trauma and describe the most important CT signs of trauma in the various organs. Because conservative nonsurgical therapy is preferred for all but the most severe injuries affecting the solid viscera, the authors emphasize the CT findings that are indications for direct therapeutic intervention. PMID:23175542

  8. Scenes from the past: initial investigation of early jurassic vertebrate fossils with multidetector CT.

    PubMed

    Bolliger, Stephan A; Ross, Steffen; Thali, Michael J; Hostettler, Bernhard; Menkveld-Gfeller, Ursula

    2012-01-01

    The study of fossils permits the reconstruction of past life on our planet and enhances our understanding of evolutionary processes. However, many fossils are difficult to recognize, being encased in a lithified matrix whose tedious removal is required before examination is possible. The authors describe the use of multidetector computed tomography (CT) in locating, identifying, and examining fossil remains of crocodilians (Mesosuchia) embedded in hard shale, all without removing the matrix. In addition, they describe how three-dimensional (3D) reformatted CT images provided details that were helpful for extraction and preparation. Multidetector CT can help experienced paleontologists localize and characterize fossils in the matrix of a promising rock specimen in a nondestructive manner. Moreover, with its capacity to generate highly accurate 3D images, multidetector CT can help determine whether the fossils warrant extraction and can assist in planning the extraction process. Thus, multidetector CT may well become an invaluable tool in the field of paleoradiology. PMID:22977034

  9. Multiplanar and three-dimensional multi-detector row CT of thoracic vessels and airways in the pediatric population.

    PubMed

    Siegel, Marilyn J

    2003-12-01

    Multi-detector row computed tomography (CT) has changed the approach to imaging of thoracic anatomy and disease in the pediatric population. At the author's institution, multi-detector row CT with multiplanar and three-dimensional reconstruction has become an important examination in the evaluation of systemic and pulmonary vasculature and the tracheobronchial tree. In some clinical situations, multi-detector row CT with reformatted images is obviating conventional angiography, which is associated with higher radiation doses and longer sedation times. Although multi-detector row CT with multiplanar and three-dimensional reconstruction is expanding the applications of CT of the thorax, its role as a diagnostic tool still needs to be better defined. The purposes of this article are to describe how to perform multi-detector row CT with multiplanar and three-dimensional reconstruction in young patients, to discuss various reconstruction techniques available, and to discuss applications in the evaluation of vascular and airways diseases. PMID:14563904

  10. Multidetector CT for Penetrating Torso Trauma: State of the Art.

    PubMed

    Dreizin, David; Munera, Felipe

    2015-11-01

    The use of computed tomography (CT) for hemodynamically stable victims of penetrating torso trauma continues to increase but remains less singular to the work-up than in blunt trauma. Research in this area has focused on the incremental benefits of CT within the context of evolving diagnostic algorithms and in conjunction with techniques such as laparoscopy, endoscopy, and angiographic intervention. This review centers on the current state of multidetector CT as a triage tool for penetrating torso trauma and the primacy of trajectory evaluation in diagnosis, while emphasizing diagnostic challenges that have lingered despite tremendous technological advances since CT was first used in this setting 3 decades ago. As treatment strategies have also changed considerably over the years in parallel with advances in CT, current management implications of organ-specific injuries depicted at multidetector CT are also discussed. PMID:26492022

  11. Extrahepatic, nonneoplastic, fat-containing lesions of the abdominopelvic cavity: spectrum of lesions, significance, and typical appearance on multidetector computed tomography.

    PubMed

    Kani, Kimia Khalatbari; Moshiri, Mariam; Bhargava, Puneet; Kolokythas, Orpheus

    2012-01-01

    Fat may be noted in a diffuse or focal manner in a variety of nonneoplastic abdominopelvic conditions. The specific signature of macroscopic fat on computed tomography along with the usually characteristic findings of these entities makes the diagnosis of most of these conditions relatively straightforward. In the intestinal tract, the "fat halo sign" usually arises in the context of subacute to chronic bowel wall inflammation. Excess fat in the renal sinus may occur with renal sinus lipomatosis or "replacement lipomatosis of the kidney." Some cases of "pancreatic lipomatosis" may culminate in steatopancreatitis and ultimately neoplastic transformations. "Fibrofatty mesenteric proliferation" is a characteristic feature of Crohn disease. In the setting of the acute abdomen, accurate diagnosis of fat-containing lesions (epiploic appendagitis or omental infarction) from other causes of the acute abdomen is critical. Mesenteric panniculitis is 1 of the causes of the "misty mesentery." Juxtacaval fat deposition is a benign process that has the potential to be confused with more serious conditions. More diffuse fat deposition (abdominal or pelvic lipomatosis) has the potential to become symptomatic by causing mass effect upon the adjacent structures. Fat can also be seen in a variety of postoperative/iatrogenic conditions or abdominal wall/diaphragmatic hernias. PMID:22285003

  12. Gd-EOB-DTPA-enhanced 3.0-Tesla MRI findings for the preoperative detection of focal liver lesions: Comparison with iodine-enhanced multi-detector computed tomography

    NASA Astrophysics Data System (ADS)

    Park, Hyong-Hu; Goo, Eun-Hoe; Im, In-Chul; Lee, Jae-Seung; Kim, Moon-Jib; Kwak, Byung-Joon; Chung, Woon-Kwan; Dong, Kyung-Rae

    2012-12-01

    The safety of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) has been confirmed, but more study is needed to assess the diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in patients with a hepatocellular carcinoma (HCC) for whom surgical treatment is considered or with a metastatic hepatoma. Research is also needed to examine the rate of detection of hepatic lesions compared to multi-detector computed tomography (MDCT), which is used most frequently to localize and characterize a HCC. Gd-EOB-DTPA-enhanced MRI and iodine-enhanced MDCT imaging were compared for the preoperative detection of focal liver lesions. The clinical usefulness of each method was examined. The current study enrolled 79 patients with focal liver lesions who preoperatively underwent MRI and MDCT. In these patients, there was less than one month between the two diagnostic modalities. Imaging data were taken before and after contrast enhancement in both methods. To evaluate the images, we analyzed the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) in the lesions and the liver parenchyma. To compare the sensitivity of the two methods, we performed a quantitative analysis of the percentage signal intensity of the liver (PSIL) on a high resolution picture archiving and communication system (PACS) monitor (paired-samples t-test, p < 0.05). The enhancement was evaluated based on a consensus of four observers. The enhancement pattern and the morphological features during the arterial and the delayed phases were correlated between the Gd-EOB-DTPA-enhanced MRI findings and the iodine-enhanced MDCT by using an adjusted x2 test. The SNRs, CNRs, and PSIL all had a greater detection rate in Gd-EOB-DTPA enhanced MRI than in iodine-enhanced MDCT. Hepatocyte-selective uptake was observed 20 minutes after the injection in the focal nodular hyperplasia (FNH, 9/9), adenoma (9/10), and highly-differentiated HCC (grade G1, 27/30). Rim

  13. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution: A cardiac phantom study

    SciTech Connect

    Greuter, M. J. W.; Groen, J. M.; Nicolai, L. J.; Dijkstra, H.; Oudkerk, M.

    2009-11-15

    Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative method which corrects for the influences of these parameters using a linear moving cardiac phantom. Methods: On a robotic arm with artificial arteries with four calcifications of increasing density, a linear movement was applied between 0 and 120 mm/s (step of 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT, and EBT using a standard acquisition protocol. The average Agatston, volume, and mass scores were determined for each velocity, calcification, and scanner. Susceptibility to motion was quantified using a cardiac motion susceptibility (CMS) index. Resemblance to EBT and physical volume and mass was quantified using a {Delta} index. Results: Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The calcium score showed a linear dependency on motion from which a correction factor could be derived. This correction factor showed a linear dependency on the mean calcification density with a good fit for all three scoring methods and all three scanners (0.73{<=}R{sup 2}{<=}0.95). The slope and offset of this correction factor showed a linear dependency on temporal resolution with a good fit for all three scoring methods and all three scanners (0.83{<=}R{sup 2}{<=}0.98). CMS was minimal for EBT and increasing values were observed for DSCT and highest values for 64-slice MDCT. CMS was minimal for mass score and increasing values were observed for volume score and highest values for Agatston score. For all densities and scoring methods DSCT showed on average the closest resemblance to EBT calcium scores. When using the correction factor, CMS index decreased on average by

  14. Multidetector Computed Tomography-Based Microstructural Analysis Reveals Reduced Bone Mineral Content and Trabecular Bone Changes in the Lumbar Spine after Transarterial Chemoembolization Therapy for Hepatocellular Carcinoma

    PubMed Central

    Takasu, Miyuki; Yamagami, Takuji; Nakamura, Yuko; Komoto, Daisuke; Kaichi, Yoko; Tani, Chihiro; Date, Shuji; Kiguchi, Masao; Awai, Kazuo

    2014-01-01

    Purpose It is well recognized that therapeutic irradiation can result in bone damage. However, long-term bone toxicity associated with computed tomography (CT) performed during interventional angiography has received little attention. The purpose of this study was to determine the prevalence of osteoporosis and trabecular microstructural changes in patients after transarterial chemoembolization (TACE) for hepatocellular carcinoma therapy using an interventional-CT system. Materials and Methods Spinal microarchitecture was examined by 64-detector CT in 81 patients who underwent TACE, 35 patients with chronic hepatitis, and 79 controls. For each patient, the volumetric CT dose index (CTDIv) during TACE (CTDIv (TACE)), the dose-length product (DLP) during TACE (DLP (TACE)), and CTDIv and DLP of routine dynamic CT scans (CTDIv (CT) and DLP (CT), respectively), were calculated as the sum since 2008. Using a three dimensional (3D) image analysis system, the tissue bone mineral density (tBMD) and trabecular parameters of the 12th thoracic vertebra were calculated. Using tBMD at a reported cutoff value of 68 mg/cm3, the prevalence of osteoporosis was assessed. Results The prevalence of osteoporosis was significantly greater in the TACE vs. the control group (39.6% vs. 18.2% for males, P<0.05 and 60.6% vs. 34.8% for females, P<0.01). Multivariate regression analysis demonstrated that sex, age, and CTDIv (CT) significantly affected the risk of osteoporosis. Of these indices, CTDIv (CT) had the highest area under the curve (AUC) (0.735). Correlation analyses of tBMD with cumulative radiation dose revealed weak correlations between tBMD and CTDIv (CT) (r2 = 0.194, P<0.001). Conclusion The prevalence of osteoporosis was significantly higher in post TACE patients than in control subjects. The cumulative radiation dose related to routine dynamic CT studies was a significant contributor to the prevalence of osteoporosis. PMID:25329933

  15. Advances in Multidetector CT Diagnosis of Pediatric Pulmonary Thromboembolism

    PubMed Central

    Thacker, Paul G.

    2016-01-01

    Although pediatric pulmonary thromboembolism is historically believed to be rare with relatively little information available in the medical literature regarding its imaging evaluation, it is more common than previously thought. Thus, it is imperative for radiologists to be aware of the most recent advances in its imaging information, particularly multidetector computed tomography (MDCT), the imaging modality of choice in the pediatric population. The overarching goal of this article is to review the most recent updates on MDCT diagnosis of pediatric pulmonary thromboembolism. PMID:26957904

  16. Analytical Computation of Effective Grid Parameters for the Finite-Difference Seismic Waveform Modeling With the PREM, IASP91, SP6, and AK135

    NASA Astrophysics Data System (ADS)

    Toyokuni, G.; Takenaka, H.

    2007-12-01

    We propose a method to obtain effective grid parameters for the finite-difference (FD) method with standard Earth models using analytical ways. In spite of the broad use of the heterogeneous FD formulation for seismic waveform modeling, accurate treatment of material discontinuities inside the grid cells has been a serious problem for many years. One possible way to solve this problem is to introduce effective grid elastic moduli and densities (effective parameters) calculated by the volume harmonic averaging of elastic moduli and volume arithmetic averaging of density in grid cells. This scheme enables us to put a material discontinuity into an arbitrary position in the spatial grids. Most of the methods used for synthetic seismogram calculation today receives the blessing of the standard Earth models, such as the PREM, IASP91, SP6, and AK135, represented as functions of normalized radius. For the FD computation of seismic waveform with such models, we first need accurate treatment of material discontinuities in radius. This study provides a numerical scheme for analytical calculations of the effective parameters for an arbitrary spatial grids in radial direction as to these major four standard Earth models making the best use of their functional features. This scheme can analytically obtain the integral volume averages through partial fraction decompositions (PFDs) and integral formulae. We have developed a FORTRAN subroutine to perform the computations, which is opened to utilization in a large variety of FD schemes ranging from 1-D to 3-D, with conventional- and staggered-grids. In the presentation, we show some numerical examples displaying the accuracy of the FD synthetics simulated with the analytical effective parameters.

  17. CHIMERA Multidetector at Laboratori Nazionali del Sud

    SciTech Connect

    Aiello, S.; Anzalone, A.; Baldo, M.; Barna, R.; Campisi, M.g.; Cardella, G.; Cavallaro, Sl., Amico, V.D.; De Filippo, E.; DePasquale, D.; Femino, S.; Geraci, E.; Giustolisi, F.; Guazzoni, P.; Iacono-Manno, C.M.; Italiano, A.; Lanzalone, G.; Lanzano, G.; LoNigro, S.; Lombardo, U.; Manfredi, G.; Pagano, A.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Sambataro, S.; Sperduto, M.L.; Sutera, C.M.; Zetta, L.

    2000-12-31

    The installation of CHIMERA multidetector, designed in order to study central collisions in heavy ion reactions at intermediate energy, is going on at LNS and the first experiment with the forward part (688 telescopes) is running since May 1999. The aim of this contribution is to present the status of the project.

  18. Multi-detector row CT of pancreatic islet cell tumors.

    PubMed

    Horton, Karen M; Hruban, Ralph H; Yeo, Charles; Fishman, Elliot K

    2006-01-01

    Pancreatic islet cell tumors (ICTs) are neuroendocrine neoplasms that produce and secrete hormones to a variable degree. These neoplasms can present a diagnostic challenge, both clinically and radiologically. ICTs can be classified as either syndromic or nonsyndromic on the basis of their clinical manifestations. Multi-detector row computed tomography (CT) plays an important role in the diagnosis and staging of both syndromic and nonsyndromic ICTs. In general, syndromic ICTs are less than 3 cm in size. They are typically hyperenhancing and are usually best seen on CT scans obtained during the arterial phase. Nonsyndromic ICTs tend to be larger than syndromic ICTs at presentation and are more likely to be cystic or necrotic. It is important for the radiologist to be familiar with appropriate CT protocol for the evaluation of patients with suspected pancreatic ICT and to understand the variable CT appearances of these neoplasms. PMID:16549609

  19. Multidetector CT diagnosis of massive hemobilia due to gallbladder polyposis in a child with metachromatic leukodystrophy.

    PubMed

    Wanner, Matthew R; Karmazyn, Boaz; Fan, Rong

    2015-12-01

    Hemobilia secondary to gallbladder polyposis is rare in children but has been reported in a few children with metachromatic leukodystrophy. We present a case with preoperative multidetector computed tomography (MDCT) diagnosis of massive hemobilia caused by gallbladder polyposis in a patient with metachromatic leukodystrophy. Our report highlights the importance of both awareness of the association of gallbladder polyposis with other syndromes such as metachromatic leukodystrophy as well as the possibility of this entity presenting with life-threatening bleeding. PMID:26160127

  20. Sinus CT scan

    MedlinePlus

    CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... 2014:chap 67. Shaw AS, Dixon AK. Multidetector computed tomography. In: Adam A, Dixon AK, eds. Grainger & Allison's ...

  1. Pelvic CT scan

    MedlinePlus

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... gov/pubmed/18381118 . Shaw AS, Dixon AK. Multidetector computed tomography. In: Grainger RC, Allison D, Adam, Dixon AK, ...

  2. Multidetector CT of the female pelvis.

    PubMed

    Siddall, Kristina A; Rubens, Deborah J

    2005-11-01

    In the emergency room setting, multidetector detector CT (MDCT) offers rapid, noninvasive, multiplanar evaluation of female patients who have acute pelvic pain. MDCT has been integrated into several of the major trauma centers, and its use may surpass the use of ultrasound in the trauma evaluation of the pregnant patient. In the nonemergent setting, MDCT can be used to stage gynecologic malignancy and to evaluate tumor recurrence. Multiplanar MDCT has received some acceptance for evaluation of small primary tumor volume and small metastatic implants. MDCT also has a role in the evaluation of pelvic varices and suspected pelvic congestion syndrome. PMID:16253664

  3. Heterogeneous Microinfarcts Caused by Coronary Microemboli: Evaluation with Multidetector CT and MR Imaging in a Swine Model1

    PubMed Central

    Saloner, David; Martin, Alastair J.; Ursell, Philip C.; Saeed, Maythem

    2010-01-01

    Purpose: To directly compare the sensitivity of 64-section multidetector computed tomography (CT) with that of 1.5-T magnetic resonance (MR) imaging in the depiction and measurement of heterogeneous 7–8-week-old microinfarcts and the quantification of regional left ventricular (LV) function and perfusion in the territory of coronary intervention in a swine model. Materials and Methods: Approval was obtained from the institutional animal committee. An x-ray/MR system was used to catheterize the left anterior descending (LAD) coronary artery with x-ray guidance and to delineate the perfusion territory. The vessel was selectively microembolized in six pigs with small-diameter embolic material (40–120 µm, 250000 count). At 7–8 weeks after microembolization, multidetector CT and MR imaging were used to assess LV function, first-pass perfusion, and delayed contrast enhancement in remote myocardium and microinfarct scars. Histochemical staining with triphenyltetrazolium chloride (TTC) was used to confirm and quantify heterogeneous microinfarct scars. The two-tailed Wilcoxon signed rank test was used to detect differences between modalities and myocardial regions. Results: The LAD territory was 32.4% ± 3.8(stadard error of the mean) of the LV mass. Multidetector CT and MR imaging have similar sensitivity in the detection of regional and global LV dysfunction and extent of microinfarct. The mean LV end-diastolic volume, end-systolic volume, and ejection fraction were 93 mL ± 8, 46 mL ± 4, and 50% ± 3, respectively, on multidetector CT images and 92 mL ± 8, 48 mL ± 5, and 48% ± 3, respectively, on MR images (P ≥ .05). The extent of heterogeneous microinfarct was not significantly different between multidetector CT (6.3% ± 0.8 of the LV mass), MR imaging (6.6% ± 0.5 of the LV mass), and TTC staining (7.0% ± 0.6 of the LV mass). First-pass multidetector CT and MR imaging demonstrated significant regional differences (P < .05) in time to peak between the

  4. Misty mesentery: a pictorial review of multidetector-row CT findings.

    PubMed

    Filippone, A; Cianci, R; Di Fabio, F; Storto, M L

    2011-04-01

    The term "misty mesentery" indicates a pathological increase in mesenteric fat attenuation at computed tomography (CT). It is frequently observed on multidetector CT (MDCT) scans performed during daily clinical practice and may be caused by various pathological conditions, including oedema, inflammation, haemorrhage, neoplastic infiltration or sclerosing mesenteritis. In patients suffering from acute abdominal disease, misty mesentery may be considered a feature of the underlying disease. Otherwise, it may represent an incidental finding on MDCT performed for other reasons. This article describes the MDCT features of misty mesentery in different diseases in order to provide a rational approach to the differential diagnosis. PMID:21311992

  5. Important Advances in Technology and Unique Applications to Cardiovascular Computed Tomography

    PubMed Central

    Chaikriangkrai, Kongkiat; Choi, Su Yeon; Nabi, Faisal; Chang, Su Min

    2014-01-01

    For the past decade, multidetector cardiac computed tomography and its main application, coronary computed tomography angiography, have been established as a noninvasive technique for anatomical assessment of coronary arteries. This new era of coronary artery evaluation by coronary computed tomography angiography has arisen from the rapid advancement in computed tomography technology, which has led to massive diagnostic and prognostic clinical studies in various patient populations. This article gives a brief overview of current multidetector cardiac computed tomography systems, developing cardiac computed tomography technologies in both hardware and software fields, innovative radiation exposure reduction measures, multidetector cardiac computed tomography functional studies, and their newer clinical applications beyond coronary computed tomography angiography. PMID:25574342

  6. Important advances in technology and unique applications to cardiovascular computed tomography.

    PubMed

    Chaikriangkrai, Kongkiat; Choi, Su Yeon; Nabi, Faisal; Chang, Su Min

    2014-01-01

    For the past decade, multidetector cardiac computed tomography and its main application, coronary computed tomography angiography, have been established as a noninvasive technique for anatomical assessment of coronary arteries. This new era of coronary artery evaluation by coronary computed tomography angiography has arisen from the rapid advancement in computed tomography technology, which has led to massive diagnostic and prognostic clinical studies in various patient populations. This article gives a brief overview of current multidetector cardiac computed tomography systems, developing cardiac computed tomography technologies in both hardware and software fields, innovative radiation exposure reduction measures, multidetector cardiac computed tomography functional studies, and their newer clinical applications beyond coronary computed tomography angiography. PMID:25574342

  7. Search for continuous gravitational waves: Metric of the multidetector F-statistic

    SciTech Connect

    Prix, Reinhard

    2007-01-15

    We develop a general formalism for the parameter-space metric of the multidetector F-statistic, which is a matched-filtering detection statistic for continuous gravitational waves. We find that there exists a whole family of F-statistic metrics, parametrized by the (unknown) amplitude parameters of the gravitational wave. The multidetector metric is shown to be expressible in terms of noise-weighted averages of single-detector contributions, which implies that the number of templates required to cover the parameter space does not scale with the number of detectors. Contrary to using a longer observation time, combining detectors of similar sensitivity is therefore the computationally cheapest way to improve the sensitivity of coherent wide-parameter searches for continuous gravitational waves. We explicitly compute the F-statistic metric family for signals from isolated spinning neutron stars, and we numerically evaluate the quality of different metric approximations in a Monte Carlo study. The metric predictions are tested against the measured mismatches and we identify regimes in which the local metric is no longer a good description of the parameter-space structure.

  8. Trapping volumetric measurement by multidetector CT in chronic obstructive pulmonary disease: Effect of CT threshold

    SciTech Connect

    Wang, Xiaohua; Yuan, Huishu; Duan, Jianghui; Du, Yipeng; Shen, Ning; He, Bei

    2013-08-15

    Purpose: The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD).Methods: Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and expiratory phase. CT thresholds of −950 Hu in inspiration and −950 to −890 Hu in expiration were used, after which trapping volumetric measurements were made using computer software. Trapping volume percentage (Vtrap%) under the different CT thresholds in the expiratory phase and below −950 Hu in the inspiratory phase was compared and correlated with lung function.Results: Mean Vtrap% was similar under −930 Hu in the expiratory phase and below −950 Hu in the inspiratory phase, being 13.18 ± 9.66 and 13.95 ± 6.72 (both lungs), respectively; this difference was not significant (P= 0.240). Vtrap% under −950 Hu in the inspiratory phase and below the −950 to −890 Hu threshold in the expiratory phase was moderately negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity and the measured value of forced expiratory volume in one second as a percentage of the predicted value.Conclusions: Trapping volumetric measurement with multidetector CT is a promising method for the quantification of COPD. It is important to know the effect of various CT thresholds on trapping volumetric measurements.

  9. Multidetector CT of Mandibular Fractures, Reductions, and Complications: A Clinically Relevant Primer for the Radiologist.

    PubMed

    Dreizin, David; Nam, Arthur J; Tirada, Nikki; Levin, Martin D; Stein, Deborah M; Bodanapally, Uttam K; Mirvis, Stuart E; Munera, Felipe

    2016-01-01

    After the nasal bones, the mandible is the second most common site of facial fractures, and mandibular fractures frequently require open reduction. In the trauma injury setting, multidetector computed tomography (CT) has become the cornerstone imaging modality for determining the most appropriate treatment management, fixation method, and surgical approach. Multidetector CT is also used to assess the adequacy of the reduction and evaluate potential complications in the postoperative period. For successful restoration of the mandible's form and function, as well as management of posttraumatic and postoperative complications, reconstructive surgeons are required to have a detailed understanding of mandibular biomechanics, occlusion, and anatomy. To provide added value in the diagnosis, treatment planning, and follow-up of mandibular fractures, radiologists should be aware of these concepts. Knowledge of the techniques commonly used to achieve occlusal and anatomic reduction and of the rationale behind the range of available treatment options for different injury patterns-from isolated and nondisplaced fractures to multisite and comminuted fractures-also is essential. This article focuses on the use of multidetector CT for pre- and postoperative evaluation of mandibular fractures and outlines fundamental concepts of diagnosis and management-beginning with an explanation of common fracture patterns and their biomechanical underpinnings, and followed by a review of the common postoperative appearances of these fractures after semirigid and rigid fixation procedures. Specific considerations regarding fractures in different regions of the tooth-bearing and non-tooth-bearing mandible and the unique issues pertaining to the edentulous atrophic mandible are reviewed, and key features that distinguish major from minor complications are described. (©)RSNA, 2016. PMID:27618328

  10. 46 CFR 7.170 - Alaska Peninsula, AK to Aleutian Islands, AK.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Alaska Peninsula, AK to Aleutian Islands, AK. 7.170... BOUNDARY LINES Alaska § 7.170 Alaska Peninsula, AK to Aleutian Islands, AK. (a) A line drawn from the southernmost extremity of Cape Kumlium to the westernmost extremity of Nakchamik Island; thence to...

  11. 46 CFR 7.170 - Alaska Peninsula, AK to Aleutian Islands, AK.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Alaska Peninsula, AK to Aleutian Islands, AK. 7.170... BOUNDARY LINES Alaska § 7.170 Alaska Peninsula, AK to Aleutian Islands, AK. (a) A line drawn from the southernmost extremity of Cape Kumlium to the westernmost extremity of Nakchamik Island; thence to...

  12. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  13. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  14. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  15. 46 CFR 7.170 - Alaska Peninsula, AK to Aleutian Islands, AK.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Alaska Peninsula, AK to Aleutian Islands, AK. 7.170... BOUNDARY LINES Alaska § 7.170 Alaska Peninsula, AK to Aleutian Islands, AK. (a) A line drawn from the southernmost extremity of Cape Kumlium to the westernmost extremity of Nakchamik Island; thence to...

  16. 46 CFR 7.170 - Alaska Peninsula, AK to Aleutian Islands, AK.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Alaska Peninsula, AK to Aleutian Islands, AK. 7.170... BOUNDARY LINES Alaska § 7.170 Alaska Peninsula, AK to Aleutian Islands, AK. (a) A line drawn from the southernmost extremity of Cape Kumlium to the westernmost extremity of Nakchamik Island; thence to...

  17. 46 CFR 7.170 - Alaska Peninsula, AK to Aleutian Islands, AK.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Alaska Peninsula, AK to Aleutian Islands, AK. 7.170... BOUNDARY LINES Alaska § 7.170 Alaska Peninsula, AK to Aleutian Islands, AK. (a) A line drawn from the southernmost extremity of Cape Kumlium to the westernmost extremity of Nakchamik Island; thence to...

  18. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  19. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  20. Value and Accuracy of Multidetector Computed Tomography in Obstructive Jaundice

    PubMed Central

    Mathew, Rishi Philip; Moorkath, Abdunnisar; Basti, Ram Shenoy; Suresh, Hadihally B.

    2016-01-01

    Summary Background Objective; To find out the role of MDCT in the evaluation of obstructive jaundice with respect to the cause and level of the obstruction, and its accuracy. To identify the advantages of MDCT with respect to other imaging modalities. To correlate MDCT findings with histopathology/surgical findings/Endoscopic Retrograde CholangioPancreatography (ERCP) findings as applicable. Material/Methods This was a prospective study conducted over a period of one year from August 2014 to August 2015. Data were collected from 50 patients with clinically suspected obstructive jaundice. CT findings were correlated with histopathology/surgical findings/ERCP findings as applicable. Results Among the 50 people studied, males and females were equal in number, and the majority belonged to the 41–60 year age group. The major cause for obstructive jaundice was choledocholithiasis. MDCT with reformatting techniques was very accurate in picking a mass as the cause for biliary obstruction and was able to differentiate a benign mass from a malignant one with high accuracy. There was 100% correlation between the CT diagnosis and the final diagnosis regarding the level and type of obstruction. MDCT was able to determine the cause of obstruction with an accuracy of 96%. Conclusions MDCT with good reformatting techniques has excellent accuracy in the evaluation of obstructive jaundice with regards to the level and cause of obstruction. PMID:27429673

  1. Cirsoid Aneurysm of Coronary Arteries Associated with Arterioventricular Fistula Evaluated by 64-Multidetector CT Coronary Angiography: Depiction of a Case

    SciTech Connect

    Marrone, Gianluca Mamone, Giuseppe; Milazzo, Mariapina; Caruso, Settimo; Baravoglia, Cesar Hernandez; Vitulo, Patrizio; Gridelli, Bruno; Luca, Angelo

    2009-05-15

    A female patient with severe pulmonary hypertension was admitted for lung transplant evaluation. As an incidental finding, the chest CT showed diffuse and dilated coronaries, not detected at previous echocardiography. A coronary CT angiography was then performed using a 64-multidetector computed tomography (MDCT) scanner to better evaluate the coronary tree. The images obtained after postprocessing demonstrated tremendously aneurysmatic and tortuous coronary arteries and the presence of a septal branch deepening into the myocardium and penetrating the right ventricle cavity, forming an abnormal arterioventricular fistula. A causal relation between the aneurysms and the fistula is suspected.

  2. Scenes from the past: multidetector CT of Egyptian mummies of the Redpath Museum.

    PubMed

    Wade, Andrew D; Garvin, Gregory J; Hurnanen, Jaana H; Williams, Licd Lana; Lawson, Barbara; Nelson, Andrew J; Tampieri, Donatella

    2012-01-01

    As a nondestructive method of historical and anthropologic inquiry, imaging has played an important role in mummy studies over the past several decades. Recent technologic advances have made multidetector computed tomography (CT) an especially useful means for deepening the present understanding of ancient cultures by examining preserved human remains. In April 2011, three ancient Egyptian human mummies from the Redpath Museum of McGill University were examined with 320-section multidetector CT as part of the IMPACT Radiological Mummy Database project headquartered at the University of Western Ontario. Whole-body scanning was performed with a section thickness of 0.5 mm and a peak voltage of 120 kVp, and the raw CT datasets were postprocessed by using smooth body and high-resolution bone convolution filters. Two of the mummies were scanned at different energy levels (80 and 135 keV). The high-resolution CT scans revealed the details of mummification and allowed observations about the socioeconomic and health status of the human subjects based on both the mummification technique used and the appearance of the remains, particularly the bones and teeth. The paleopathologic information obtained from the scans confirmed some findings in studies performed in the same mummies in the late 19th and 20th centuries. The CT scans also demonstrated a high degree of variability in Egyptian mortuary practice, variability that is not generally recognized in the literature. Unusual features that were observed included a relatively uncommon retained heart in mummy RM2718, retained lungs in a mummy from which the heart had been extracted (RM2720), and a cartonnage plaque placed over the left abdomen of a mummy that had been eviscerated transperineally (RM2717). PMID:22787004

  3. 46 CFR 7.150 - Canadian (BC) and United States (AK) Borders to Cape Spencer, AK.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Canadian (BC) and United States (AK) Borders to Cape Spencer, AK. 7.150 Section 7.150 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.150 Canadian (BC) and United States (AK) Borders to...

  4. 46 CFR 7.150 - Canadian (BC) and United States (AK) Borders to Cape Spencer, AK.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Canadian (BC) and United States (AK) Borders to Cape Spencer, AK. 7.150 Section 7.150 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.150 Canadian (BC) and United States (AK) Borders to...

  5. 64 Slice multi-detector row cardiac CT.

    PubMed

    Pannu, Harpreet K; Johnson, Pamela T; Fishman, Elliot K

    2009-01-01

    Cardiac imaging is feasible with multi-detector row (MDCT) scanners. Coronary arterial anatomy and both non-calcified and calcified plaques are depicted at CT coronary angiography. Vessel wall pathology and luminal diameter are depicted, and secondary myocardial changes may also be seen. Diagnostic capacity has increased with technological advancement, and preliminary investigations confirm the utility of 64-MDCT in low- and intermediate-risk patients who present to the emergency department with acute chest pain. The clinical indications, 64-MDCT technique, and MDCT findings in coronary artery disease are reviewed. PMID:18941811

  6. Multidetector CT of pulmonary cavitation: filling in the holes.

    PubMed

    Mortensen, K H; Babar, J L; Balan, A

    2015-04-01

    Pulmonary cavitation causes significant morbidity and mortality. Early diagnosis of the presence and aetiology of a cavity is therefore crucial in order to avoid further demise in both the localized pulmonary and systemic disorders that may manifest with pulmonary cavity formation. Multidetector CT has become the principal diagnostic technique for detecting pulmonary cavitation and its complications. This review provides an overview of the aetiologies and their imaging findings using this technique. Combining a literature review with case illustration, a synopsis of the different imaging features and constellations is provided, which may suggest a particular cause and aid the differentiation from diseases with similar findings. PMID:25623513

  7. Cam-type deformities: Concepts, criteria, and multidetector CT features.

    PubMed

    Mellado, J M; Radi, N

    2015-01-01

    Interpreting imaging studies of a painful hip requires detailed knowledge of the regional anatomy. Some variants of the proximal femur, such as cam-type deformities, can course asymptomatically or cause femoroacetabular impingement. The principal numerical criterion for defining cam-type deformities, the alpha angle, has some limitations. In this article, we review the anatomic variants of the anterior aspect of the proximal femur, focusing on cam-type deformities. Using diagrams and multidetector CT images, we describe the parameters that are useful for characterizing these deformities in different imaging techniques. We also discuss the potential correspondence of imaging findings of cam-type deformities with the terms coined by anatomists and anthropologists to describe these phenomena. PMID:25660594

  8. Toroid cavity/coil NMR multi-detector

    DOEpatents

    Gerald, II, Rex E.; Meadows, Alexander D.; Gregar, Joseph S.; Rathke, Jerome W.

    2007-09-18

    An analytical device for rapid, non-invasive nuclear magnetic resonance (NMR) spectroscopy of multiple samples using a single spectrometer is provided. A modified toroid cavity/coil detector (TCD), and methods for conducting the simultaneous acquisition of NMR data for multiple samples including a protocol for testing NMR multi-detectors are provided. One embodiment includes a plurality of LC resonant circuits including spatially separated toroid coil inductors, each toroid coil inductor enveloping its corresponding sample volume, and tuned to resonate at a predefined frequency using a variable capacitor. The toroid coil is formed into a loop, where both ends of the toroid coil are brought into coincidence. Another embodiment includes multiple micro Helmholtz coils arranged on a circular perimeter concentric with a central conductor of the toroid cavity.

  9. Cardiac Conduction System: Delineation of Anatomic Landmarks With Multidetector CT

    PubMed Central

    Saremi, Farhood; Torrone, Maria; Yashar, Nooshin

    2009-01-01

    Major components of the cardiac conduction system including the sinoatrial node (SAN), atrioventricular node (AVN), the His Bundle, and the right and left bundle branches are too small to be directly visualized by multidetector CT (MDCT) given the limited spatial resolution of current scanners. However, the related anatomic landmarks and variants of this system a well as the areas with special interest to electrophysiologists can be reliably demonstrated by MDCT. Some of these structures and landmarks include the right SAN artery, right atrial cavotricuspid isthmus, Koch triangle, AVN artery, interatrial muscle bundles, and pulmonary veins. In addition, MDCT has an imperative role in demarcating potential arrhythmogenic structures. The aim of this review will be to assess the extent at which MDCT can outline the described anatomic landmarks and therefore provide crucial information used in clinical practice. PMID:19898655

  10. Influence of z overscanning on normalized effective doses calculated for pediatric patients undergoing multidetector CT examinations

    SciTech Connect

    Tzedakis, Antonis; Damilakis, John; Perisinakis, Kostas; Karantanas, Apostolos; Karabekios, Spiros; Gourtsoyiannis, Nicholas

    2007-04-15

    The purpose of this study was to evaluate the effect of z overscanning on normalized effective dose for pediatric patients undergoing multidetector-computed tomography (CT) examinations. Five commercially available mathematical anthropomorphic phantoms representing newborn, 1-, 5-, 10-, and 15-year-old patients and the Monte Carlo N-Particle (MCNP, version 4C2) radiation transport code were employed in the current study to simulate pediatric CT exposures. For all phantoms, axial and helical examinations at 120 kV tube voltage were simulated. Scans performed at 80 kV were also simulated. Sex-specific normalized effective doses were estimated for four standard CT examinations i.e., head-neck, chest, abdomen-pelvis, and trunk, for all pediatric phantoms. Data for both axial and helical mode acquisition were obtained. In the helical mode, z overscanning was taken into account. The validity of the Monte Carlo results was verified by comparison with dose data obtained using thermoluminescence dosimetry and a physical pediatric anthropomorphic phantom simulating a 10-year-old child. In all cases normalized effective dose values were found to increase with increasing z overscanning. The percentage differences in normalized data between axial and helical scans may reach 43%, 70%, 36%, and 26% for head-neck, chest, abdomen-pelvis, and trunk studies, respectively. Normalized data for female pediatric patients was in general higher compared to male patients for all ages, examined regions, and z overscanning values. For both male and female children, the normalized effective dose values were reduced as the age was increased. For the same typical exposure conditions, dose values decreased when lower tube voltage was used; for a 1-year-old child, for example, the effective dose was 3.8 times lower when 80 kV instead of 120 kV was used. Normalized data for the estimation of effective dose to pediatric patients undergoing standard axial and helical CT examinations on an

  11. Influence of z overscanning on normalized effective doses calculated for pediatric patients undergoing multidetector CT examinations.

    PubMed

    Tzedakis, Antonis; Damilakis, John; Perisinakis, Kostas; Karantanas, Apostolos; Karabekios, Spiros; Gourtsoyiannis, Nicholas

    2007-04-01

    The purpose of this study was to evaluate the effect of z overscanning on normalized effective dose for pediatric patients undergoing multidetector-computed tomography (CT) examinations. Five commercially available mathematical anthropomorphic phantoms representing newborn, 1-, 5-, 10-, and 15-year-old patients and the Monte Carlo N-Particle (MCNP, version 4C2) radiation transport code were employed in the current study to simulate pediatric CT exposures. For all phantoms, axial and helical examinations at 120 kV tube voltage were simulated. Scans performed at 80 kV were also simulated. Sex-specific normalized effective doses were estimated for four standard CT examinations i.e., head-neck, chest, abdomen-pelvis, and trunk, for all pediatric phantoms. Data for both axial and helical mode acquisition were obtained. In the helical mode, z overscanning was taken into account. The validity of the Monte Carlo results was verified by comparison with dose data obtained using thermoluminescence dosimetry and a physical pediatric anthropomorphic phantom simulating a 10-year-old child. In all cases normalized effective dose values were found to increase with increasing z overscanning. The percentage differences in normalized data between axial and helical scans may reach 43%, 70%, 36%, and 26% for head-neck, chest, abdomen-pelvis, and trunk studies, respectively. Normalized data for female pediatric patients was in general higher compared to male patients for all ages, examined regions, and z overscanning values. For both male and female children, the normalized effective dose values were reduced as the age was increased. For the same typical exposure conditions, dose values decreased when lower tube voltage was used; for a 1-year-old child, for example, the effective dose was 3.8 times lower when 80 kV instead of 120 kV was used. Normalized data for the estimation of effective dose to pediatric patients undergoing standard axial and helical CT examinations on an

  12. Contrast enhanced multi-detector CT and MR findings of a well-differentiated pancreatic vipoma

    PubMed Central

    Camera, Luigi; Severino, Rosa; Faggiano, Antongiulio; Masone, Stefania; Mansueto, Gelsomina; Maurea, Simone; Fonti, Rosa; Salvatore, Marco

    2014-01-01

    Pancreatic vipoma is an extremely rare tumor accounting for less than 2% of endocrine pancreatic neoplasms with a reported incidence of 0.1-0.6 per million. While cross-sectional imaging findings are usually not specific, exact localization of the tumor by means of either computed tomography (CT) or magnetic resonance (MR) is pivotal for surgical planning. However, cross-sectional imaging findings are usually not specific and further characterization of the tumor may only be achieved by somatostatin-receptor scintigraphy (SRS). We report the case of a 70 years old female with a two years history of watery diarrhoea who was found to have a solid, inhomogeneously enhancing lesion at the level of the pancreatic tail at Gadolinium-enhanced MR (Somatom Trio 3T, Siemens, Germany). The tumor had been prospectively overlooked at a contrast-enhanced multi-detector CT (Aquilion 64, Toshiba, Japan) performed after i.v. bolus injection of only 100 cc of iodinated non ionic contrast media because of a chronic renal failure (3.4 mg/mL) but it was subsequently confirmed by SRS. The patient first underwent a successful symptomatic treatment with somatostatin analogues and was then submitted to a distal pancreasectomy with splenectomy to remove a capsulated whitish tumor which turned out to be a well-differentiated vipoma at histological and immuno-histochemical analysis. PMID:25349667

  13. Detection, visualization and evaluation of anomalous coronary anatomy on 16-slice multidetector-row CT.

    PubMed

    van Ooijen, Peter M A; Dorgelo, Joost; Zijlstra, Felix; Oudkerk, Matthijs

    2004-12-01

    Early identification and evaluation of relatively frequent anomalous coronary anatomy is quite relevant because of the occurrence of sudden cardiac death or related symptoms of myocardial ischemia. Selective coronary angiography (CAG) is invasive, expensive and cannot always provide the required information adequately. Recently, non-invasive imaging techniques such as magnetic resonance imaging and multidetector-row computed tomography (MDCT) have been shown to provide a good anatomical view of the coronary artery tree. This study aims to demonstrate the value of 16-MDCT for evaluation of anomalous coronary anatomy. In 13 patients scanned using 16-MDCT, six different coronary anomalies were diagnosed [two absent left main, one single vessel left coronary artery (LCA), three LCA originating from the right (two with interarterial course), six right coronary artery originating from the left, one double left anterior descending (LAD)]. Mean diagnostic quality, recorded by two observers using a 5-point scale (1= non-diagnostic to 5= excellent diagnostic quality), resulted in a mean score of 3.73 (SD 1.19) without any non-diagnostic result. MDCT offers an accurate diagnostic modality to visualize the origin and course of anomalous coronary arteries by a three-dimensional display of anatomy. Shortcomings in CAG can be overcome by the use of contrast-enhanced MDCT. PMID:15452665

  14. Multi-detector CT features of acute intestinal ischemia and their prognostic correlations

    PubMed Central

    Moschetta, Marco; Telegrafo, Michele; Rella, Leonarda; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe

    2014-01-01

    Acute intestinal ischemia is an abdominal emergency occurring in nearly 1% of patients presenting with acute abdomen. The causes can be occlusive or non occlusive. Early diagnosis is important to improve survival rates. In most cases of late or missed diagnosis, the mortality rate from intestinal infarction is very high, with a reported value ranging from 60% to 90%. Multi-detector computed tomography (MDCT) is a fundamental imaging technique that must be promptly performed in all patients with suspected bowel ischemia. Thanks to the new dedicated reconstruction program, its diagnostic potential is much improved compared to the past and currently it is superior to that of any other noninvasive technique. The increased spatial and temporal resolution, high-quality multi-planar reconstructions, maximum intensity projections, vessel probe, surface-shaded volume rending and tissue transition projections make MDCT the gold standard for the diagnosis of intestinal ischemia, with reported sensitivity, specificity, positive and negative predictive values of 64%-93%, 92%-100%, 90%-100% and 94%-98%, respectively. MDCT contributes to appropriate treatment planning and provides important prognostic information thanks to its ability to define the nature and extent of the disease. The purpose of this review is to examine the diagnostic and prognostic role of MDCT in bowel ischemia with special regard to the state of art new reconstruction software. PMID:24876917

  15. AK-cut crystal resonators

    NASA Technical Reports Server (NTRS)

    Kahan, A.; Euler, F. K.

    1983-01-01

    Calculations have predicted the existence of crystallographically doubly rotated quartz orientations with turnover temperatures which are considerably less sensitive to angular misorientation then comparable AT- or BT-cuts. These crystals are arbitrarily designated as the AK-cut. Experimental data is given for seven orientations, phi-angle variations between 30-46 deg and theta-angle variations between 21-28 deg measured on 3.3-3.4 MHz fundamental mode resonators vibrating in the thickness shear c-mode. The experimental turnover temperatures of these resonators are between 80 C and 150 C, in general agreement with calculated values. The normalized frequency change as a function of temperature has been fitted with a cubic equation.

  16. Quantitative Features of Liver Lesions, Lung Nodules, and Renal Stones at Multi-Detector Row CT Examinations: Dependency on Radiation Dose and Reconstruction Algorithm.

    PubMed

    Solomon, Justin; Mileto, Achille; Nelson, Rendon C; Roy Choudhury, Kingshuk; Samei, Ehsan

    2016-04-01

    Purpose To determine if radiation dose and reconstruction algorithm affect the computer-based extraction and analysis of quantitative imaging features in lung nodules, liver lesions, and renal stones at multi-detector row computed tomography (CT). Materials and Methods Retrospective analysis of data from a prospective, multicenter, HIPAA-compliant, institutional review board-approved clinical trial was performed by extracting 23 quantitative imaging features (size, shape, attenuation, edge sharpness, pixel value distribution, and texture) of lesions on multi-detector row CT images of 20 adult patients (14 men, six women; mean age, 63 years; range, 38-72 years) referred for known or suspected focal liver lesions, lung nodules, or kidney stones. Data were acquired between September 2011 and April 2012. All multi-detector row CT scans were performed at two different radiation dose levels; images were reconstructed with filtered back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) algorithms. A linear mixed-effects model was used to assess the effect of radiation dose and reconstruction algorithm on extracted features. Results Among the 23 imaging features assessed, radiation dose had a significant effect on five, three, and four of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). Adaptive statistical iterative reconstruction had a significant effect on three, one, and one of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). MBIR reconstruction had a significant effect on nine, 11, and 15 of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). Of note, the measured size of lung nodules and renal stones with MBIR was significantly different than those for the other two algorithms (P < .002 for all comparisons). Although lesion texture was

  17. Novel ultrahigh resolution data acquisition and image reconstruction for multi-detector row CT

    SciTech Connect

    Flohr, T. G.; Stierstorfer, K.; Suess, C.; Schmidt, B.; Primak, A. N.; McCollough, C. H.

    2007-05-15

    We present and evaluate a special ultrahigh resolution mode providing considerably enhanced spatial resolution both in the scan plane and in the z-axis direction for a routine medical multi-detector row computed tomography (CT) system. Data acquisition is performed by using a flying focal spot both in the scan plane and in the z-axis direction in combination with tantalum grids that are inserted in front of the multi-row detector to reduce the aperture of the detector elements both in-plane and in the z-axis direction. The dose utilization of the system for standard applications is not affected, since the grids are moved into place only when needed and are removed for standard scanning. By means of this technique, image slices with a nominal section width of 0.4 mm (measured full width at half maximum=0.45 mm) can be reconstructed in spiral mode on a CT system with a detector configuration of 32x0.6 mm. The measured 2% value of the in-plane modulation transfer function (MTF) is 20.4 lp/cm, the measured 2% value of the longitudinal (z axis) MTF is 21.5 lp/cm. In a resolution phantom with metal line pair test patterns, spatial resolution of 20 lp/cm can be demonstrated both in the scan plane and along the z axis. This corresponds to an object size of 0.25 mm that can be resolved. The new mode is intended for ultrahigh resolution bone imaging, in particular for wrists, joints, and inner ear studies, where a higher level of image noise due to the reduced aperture is an acceptable trade-off for the clinical benefit brought about by the improved spatial resolution.

  18. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required. PMID:16211320

  19. New absorbed dose measurement with cylindrical water phantoms for multidetector CT.

    PubMed

    Ohno, Takeshi; Araki, Fujio; Onizuka, Ryota; Hioki, Kazunari; Tomiyama, Yuuki; Yamashita, Yusuke

    2015-06-01

    The aim of this study was to develop new dosimetry with cylindrical water phantoms for multidetector computed tomography (MDCT). The ionization measurement was performed with a Farmer ionization chamber at the center and four peripheral points in the body-type and head-type cylindrical water phantoms. The ionization was converted to the absorbed dose using a (60)Co absorbed-dose-to-water calibration factor and Monte Carlo (MC) -calculated correction factors. The correction factors were calculated from MDCT (Brilliance iCT, 64-slice, Philips Electronics) modeled with GMctdospp (IMPS, Germany) software based on the EGSnrc MC code. The spectrum of incident x-ray beams and the configuration of a bowtie filter for MDCT were determined so that calculated photon intensity attenuation curves for aluminum (Al) and calculated off-center ratio (OCR) profiles in air coincided with those measured. The MC-calculated doses were calibrated by the absorbed dose measured at the center in both cylindrical water phantoms. Calculated doses were compared with measured doses at four peripheral points and the center in the phantom for various beam pitches and beam collimations. The calibration factors and the uncertainty of the absorbed dose determined using this method were also compared with those obtained by CTDIair (CT dose index in air). Calculated Al half-value layers and OCRs in air were within 0.3% and 3% agreement with the measured values, respectively. Calculated doses at four peripheral points and the centers for various beam pitches and beam collimations were within 5% and 2% agreement with measured values, respectively. The MC-calibration factors by our method were 44-50% lower than values by CTDIair due to the overbeaming effect. However, the calibration factors for CTDIair agreed within 5% with those of our method after correction for the overbeaming effect. Our method makes it possible to directly measure the absorbed dose for MDCT and is more robust and accurate than the

  20. New absorbed dose measurement with cylindrical water phantoms for multidetector CT

    NASA Astrophysics Data System (ADS)

    Ohno, Takeshi; Araki, Fujio; Onizuka, Ryota; Hioki, Kazunari; Tomiyama, Yuuki; Yamashita, Yusuke

    2015-06-01

    The aim of this study was to develop new dosimetry with cylindrical water phantoms for multidetector computed tomography (MDCT). The ionization measurement was performed with a Farmer ionization chamber at the center and four peripheral points in the body-type and head-type cylindrical water phantoms. The ionization was converted to the absorbed dose using a 60Co absorbed-dose-to-water calibration factor and Monte Carlo (MC) -calculated correction factors. The correction factors were calculated from MDCT (Brilliance iCT, 64-slice, Philips Electronics) modeled with GMctdospp (IMPS, Germany) software based on the EGSnrc MC code. The spectrum of incident x-ray beams and the configuration of a bowtie filter for MDCT were determined so that calculated photon intensity attenuation curves for aluminum (Al) and calculated off-center ratio (OCR) profiles in air coincided with those measured. The MC-calculated doses were calibrated by the absorbed dose measured at the center in both cylindrical water phantoms. Calculated doses were compared with measured doses at four peripheral points and the center in the phantom for various beam pitches and beam collimations. The calibration factors and the uncertainty of the absorbed dose determined using this method were also compared with those obtained by CTDIair (CT dose index in air). Calculated Al half-value layers and OCRs in air were within 0.3% and 3% agreement with the measured values, respectively. Calculated doses at four peripheral points and the centers for various beam pitches and beam collimations were within 5% and 2% agreement with measured values, respectively. The MC-calibration factors by our method were 44-50% lower than values by CTDIair due to the overbeaming effect. However, the calibration factors for CTDIair agreed within 5% with those of our method after correction for the overbeaming effect. Our method makes it possible to directly measure the absorbed dose for MDCT and is more robust and accurate than the

  1. Pancreatic pseudoaneurysm in a child with hereditary pancreatitis: diagnosis with multidetector CT angiography.

    PubMed

    Ahmed, Hossam K; Hagspiel, Klaus D; McGahren, Eugene D; Angle, John F; Leung, Daniel A; Spinosa, David J; Matsumoto, Alan H; Rodgers, Bradley M

    2004-08-01

    Pseudoaneurysm formation is a serious vascular complication of pancreatitis. It most commonly affects splenic and gastroduodenal arteries. We report a rare case of superior mesenteric artery pseudoaneurysm in a child with hereditary pancreatitis. Multidetector CT angiography allowed the comprehensive assessment of the aneurysm and allowed accurate surgical planning obviating the need for catheter angiography. PMID:15107963

  2. Study of statistical properties of hybrid statistic in coherent multidetector compact binary coalescences search

    NASA Astrophysics Data System (ADS)

    Haris, K.; Pai, Archana

    2016-05-01

    In this article, we revisit the coherent gravitational wave search problem of compact binary coalescences with multidetector network consisting of advanced interferometers like LIGO-Virgo. Based on the loss of the optimal multidetector signal-to-noise ratio (SNR), we construct a hybrid statistic as a best of maximum-likelihood-ratio (MLR) statistic tuned for face-on and face-off binaries. The statistical properties of the hybrid statistic is studied. The performance of this hybrid statistic is compared with that of the coherent MLR statistic for generic inclination angles. Owing to the single synthetic data stream, the hybrid statistic gives few false alarms compared to the multidetector MLR statistic and small fractional loss in the optimum SNR for a large range of binary inclinations. We demonstrate that, for a LIGO-Virgo network and binary inclination ɛ <7 0 ° and ɛ >11 0 ° , the hybrid statistic captures more than 98% of the network optimum matched filter SNR with a low false alarm rate. The Monte Carlo exercise with two distributions of incoming inclination angles—namely, U [cos ɛ ] and a more realistic distribution proposed by B. F. Schutz [Classical Quantum Gravity 28, 125023 (2011)]—are performed with the hybrid statistic and give approximately 5% and 7% higher detection probabilities, respectively, compared to the two stream multidetector MLR statistic for a fixed false alarm probability of 1 0-5.

  3. 77 FR 7228 - Alaska Disaster #AK-00023

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... ADMINISTRATION Alaska Disaster AK-00023 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This... applications to: U.S. Small Business Administration, Processing and Disbursement Center, 14925 Kingsport Road.... Small Business Administration, 409 3rd Street SW., Suite 6050, Washington, DC 20416....

  4. 76 FR 35936 - Alaska Disaster #AK-00020

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... From the Federal Register Online via the Government Publishing Office U.S. SMALL BUSINESS ADMINISTRATION Alaska Disaster AK-00020 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement...

  5. 78 FR 39821 - Alaska Disaster #AK-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... From the Federal Register Online via the Government Publishing Office ] SMALL BUSINESS ADMINISTRATION Alaska Disaster AK-00029 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This... applications to: U.S. Small Business Administration, Processing and Disbursement Center, 14925 Kingsport...

  6. 78 FR 39822 - Alaska Disaster #AK-00028

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alaska Disaster AK-00028 AGENCY: U.S. Small Business Administration. ACTION: Notice SUMMARY: This... Deadline Date: 03/25/2014. ADDRESSES: Submit completed loan applications to: U.S. Small...

  7. Computed Tomography of Pancreatitis and Pancreatic Cancer.

    PubMed

    Furlow, Bryant

    2015-01-01

    Pancreatic disease often is asymptomatic until tissue damage and complications occur or until malignancies have reached advanced stages and have metastasized. Contrast-enhanced multidetector computed tomography plays a central role in diagnosing, staging, and treatment planning for pancreatitis and pancreatic cancer. This article introduces the functional anatomy of the pancreas and common bile duct and the epidemiology, pathobiology, and computed tomography imaging of pancreatitis, calculi, and pancreatic cancer. PMID:26199449

  8. Dual-energy CT revisited with multidetector CT: review of principles and clinical applications.

    PubMed

    Karçaaltıncaba, Muşturay; Aktaş, Aykut

    2011-09-01

    Although dual-energy CT (DECT) was first conceived in the 1970s, it was not widely used for CT indications. Recently, the simultaneous acquisition of volumetric dual-energy data has been introduced using multidetector CT (MDCT) with two X-ray tubes and rapid kVp switching (gemstone spectral imaging). Two major advantages of DECT are material decomposition by acquiring two image series with different kVp and the elimination of misregistration artifacts. Hounsfield unit measurements by DECT are not absolute and can change depending on the kVp used for an acquisition. Typically, a combination of 80/140 kVp is used for DECT, but for some applications, 100/140 kVp is preferred. In this study, we summarized the clinical applications of DECT and included images that were acquired using the dual-source CT and rapid kVp switching. In general, unenhanced images can be avoided by using DECT for body and neurological applications; iodine can be removed from the image, and a virtual, non-contrast (water) image can be obtained. Neuroradiological applications allow for the removal of bone and calcium from the carotid and brain CT angiography. Thorax applications include perfusion imaging in patients with pulmonary thromboemboli and other chest diseases, xenon ventilation-perfusion imaging and solitary nodule characterization. Cardiac applications include dual-energy cardiac perfusion, viability and cardiac iron detection. The removal of calcific plaques from arteries, bone removal and aortic stent graft evaluation may be achieved in the vascular system. Abdominal applications include the detection and characterization of liver and pancreas masses, the diagnosis of steatosis and iron overload, DECT colonoscopy and CT cholangiography. Urinary system applications are urinary calculi characterization (uric acid vs. non-uric acid), renal cyst characterization and mass characterization. Musculoskeletal applications permit the differentiation of gout from pseudogout and a reduction of

  9. Preoperative Gross Classification of Gastric Adenocarcinoma: Comparison of Double Contrast-Enhanced Ultrasound and Multi-Detector Row CT.

    PubMed

    Yan, Caoxin; Bao, Xiaofeng; Shentu, Weihui; Chen, Jian; Liu, Chunmei; Ye, Qin; Wang, Liuhong; Tan, Yangbin; Huang, Pintong

    2016-07-01

    The aim of this study was to compare the accuracy of multi-detector computed tomography (MDCT) with double contrast-enhanced ultrasound (DCEUS), in which intravenous microbubbles are used alongside oral contrast-enhanced ultrasound, in determining the gross classification of patients with gastric carcinoma (GC). Altogether, 239 patients with GC proved by histology after endoscopic biopsy were included in this study. DCEUS and MDCT were performed pre-operatively. The diagnostic accuracies of DCEUS and MDCT in determining the gross classification were calculated and compared. The overall accuracy of DCEUS in determining the gross appearance of GC was higher than that of MDCT (84.9% vs. 79.9%, p < 0.001). There was no significant difference in accuracy between DCEUS and MDCT for Borrmann I and IV classifications of advanced gastric cancer (χ(2), p = 0.323 for Borrmann type I, p = 0.141 for Borrmann type IV). The accuracy of DCEUS for early GC and Borrmann II and III classifications of GC was higher than that of MDCT (χ(2), p = 0.000 for all). DCEUS may be regarded as a valuable complementary tool to MDCT in determining the gross appearance of gastric adenocarcinoma pre-operatively. PMID:27072076

  10. Cardiac Multi-detector CT Segmentation Based on Multiscale Directional Edge Detector and 3D Level Set.

    PubMed

    Antunes, Sofia; Esposito, Antonio; Palmisano, Anna; Colantoni, Caterina; Cerutti, Sergio; Rizzo, Giovanna

    2016-05-01

    Extraction of the cardiac surfaces of interest from multi-detector computed tomographic (MDCT) data is a pre-requisite step for cardiac analysis, as well as for image guidance procedures. Most of the existing methods need manual corrections, which is time-consuming. We present a fully automatic segmentation technique for the extraction of the right ventricle, left ventricular endocardium and epicardium from MDCT images. The method consists in a 3D level set surface evolution approach coupled to a new stopping function based on a multiscale directional second derivative Gaussian filter, which is able to stop propagation precisely on the real boundary of the structures of interest. We validated the segmentation method on 18 MDCT volumes from healthy and pathologic subjects using manual segmentation performed by a team of expert radiologists as gold standard. Segmentation errors were assessed for each structure resulting in a surface-to-surface mean error below 0.5 mm and a percentage of surface distance with errors less than 1 mm above 80%. Moreover, in comparison to other segmentation approaches, already proposed in previous work, our method presented an improved accuracy (with surface distance errors less than 1 mm increased of 8-20% for all structures). The obtained results suggest that our approach is accurate and effective for the segmentation of ventricular cavities and myocardium from MDCT images. PMID:26319010

  11. AkF ¯ chiral gauge theories

    NASA Astrophysics Data System (ADS)

    Shi, Yan-Liang; Shrock, Robert

    2015-11-01

    We study asymptotically free chiral gauge theories with an SU (N ) gauge group and chiral fermions transforming according to the antisymmetric rank-k tensor representation, Ak≡[k ]N , and the requisite number, nF ¯, of copies of fermions in the conjugate fundamental representation, F ¯ ≡[1] ¯ N , to render the theories anomaly-free. We denote these as AkF ¯ theories. We take N ≥2 k +1 so that nF ¯≥1 . The A2F ¯ theories form an infinite family with N ≥5 , but we show that the A3F ¯ and A4F ¯ theories are only asymptotically free for N in the respective ranges 7 ≤N ≤17 and 9 ≤N ≤11 , and that there are no asymptotically free AkF ¯ theories with k ≥5 . We investigate the types of ultraviolet to infrared evolution for these AkF ¯ theories and find that, depending on k and N , they may lead to a non-Abelian Coulomb phase, or may involve confinement with massless gauge-singlet composite fermions, bilinear fermion condensation with dynamical gauge and global symmetry breaking, or formation of multifermion condensates that preserve the gauge symmetry. We also show that there are no asymptotically free, anomaly-free SU (N ) SkF ¯ chiral gauge theories with k ≥3 , where Sk denotes the rank-k symmetric representation.

  12. Imaging of Herniated Discs of the Cervical Spine: Inter-Modality Differences between 64-Slice Multidetector CT and 1.5-T MRI

    PubMed Central

    Yi, Ji Sook; Han, Jong Kyu; Kim, Hyun-Joo

    2015-01-01

    Objective To assess inter-modality variability when evaluating cervical intervertebral disc herniation using 64-slice multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI). Materials and Methods Three musculoskeletal radiologists independently reviewed cervical spine 1.5-T MRI and 64-slice MDCT data on C2-3 though C6-7 of 51 patients in the context of intervertebral disc herniation. Interobserver and inter-modality agreements were expressed as unweighted kappa values. Weighted kappa statistics were used to assess the extents of agreement in terms of the number of involved segments (NIS) in disc herniation and epicenter measurements collected using MDCT and MRI. Results The interobserver agreement rates upon evaluation of disc morphology by the three radiologists were in fair to moderate agreement (k = 0.39-0.53 for MDCT images; k = 0.45-0.56 for MRIs). When the disc morphology was categorized into two and four grades, the inter-modality agreement rates were moderate (k-value, 0.59) and substantial (k-value, 0.66), respectively. The inter-modality agreements for evaluations of the NIS (k-value, 0.78) and the epicenter (k-value, 0.79) were substantial. Also, the interobserver agreements for the NIS (CT; k-value, 0.85 and MRI; k-value, 0.88) and epicenter (CT; k-value, 0.74 and MRI; k-value, 0.70) evaluations by two readers were substantial. MDCT tended to underestimate the extent of herniated disc lesions compared with MRI. Conclusion Multidetector-row computed tomography and MRI showed a moderate-to-substantial degree of inter-modality agreement for the assessment of herniated cervical discs. MDCT images have a tendency to underestimate the anterior/posterior extent of the herniated disc compared with MRI. PMID:26175589

  13. 40 CFR Appendixes A-K to Part 51 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 2 2012-07-01 2012-07-01 false A Appendixes A-K to Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Appendixes A-K to Part 51...

  14. 40 CFR Appendixes A-K to Part 51 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 2 2014-07-01 2014-07-01 false A Appendixes A-K to Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Appendixes A-K to Part 51...

  15. 40 CFR Appendixes A-K to Part 51 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 2 2013-07-01 2013-07-01 false A Appendixes A-K to Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Appendixes A-K to Part 51...

  16. 40 CFR Appendixes A-K to Part 51 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 2 2011-07-01 2011-07-01 false A Appendixes A-K to Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Appendixes A-K to Part 51...

  17. 46 CFR 7.180 - Kotzebue Sound, AK.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Kotzebue Sound, AK. 7.180 Section 7.180 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.180 Kotzebue Sound, AK. A line drawn from Cape Espenberg Light to latitude 66°52′ N. longitude 163°28′ W.;...

  18. 46 CFR 7.180 - Kotzebue Sound, AK.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Kotzebue Sound, AK. 7.180 Section 7.180 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.180 Kotzebue Sound, AK. A line drawn from Cape Espenberg Light to latitude 66°52′ N. longitude 163°28′ W.;...

  19. 46 CFR 7.180 - Kotzebue Sound, AK.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Kotzebue Sound, AK. 7.180 Section 7.180 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.180 Kotzebue Sound, AK. A line drawn from Cape Espenberg Light to latitude 66°52′ N. longitude 163°28′ W.;...

  20. 46 CFR 7.180 - Kotzebue Sound, AK.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Kotzebue Sound, AK. 7.180 Section 7.180 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.180 Kotzebue Sound, AK. A line drawn from Cape Espenberg Light to latitude 66°52′ N. longitude 163°28′ W.;...

  1. 46 CFR 7.180 - Kotzebue Sound, AK.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Kotzebue Sound, AK. 7.180 Section 7.180 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Alaska § 7.180 Kotzebue Sound, AK. A line drawn from Cape Espenberg Light to latitude 66°52′ N. longitude 163°28′ W.;...

  2. 76 FR 43824 - Revision of Class E Airspace; Talkeetna, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... revise Class E airspace at Talkeetna, AK (76 FR 27619). Interested parties were invited to participate in... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Talkeetna, AK AGENCY:...

  3. 77 FR 60660 - Proposed Establishment Class E Airspace; Kasigluk, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ...: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389... Federal Aviation Administration 14 CFR Part 71 Proposed Establishment Class E Airspace; Kasigluk, AK...: This action proposes to establish Class E airspace at Kasigluk Airport, Kasigluk, AK, to...

  4. 76 FR 66854 - Amendment of Class E Airspace; Nuiqsut, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... rulemaking (NPRM) in the Federal Register to revise Class E airspace at Nuiqsut, AK (76 FR 49386). Interested..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Nuiqsut, AK AGENCY:...

  5. 76 FR 8625 - Revision of Class E Airspace; Savoonga, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... Federal Register to amend Class E airspace at Savoonga, AK (75 FR 77574). Interested parties were invited... read as follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Savoonga, AK AGENCY:...

  6. 76 FR 8627 - Revision of Class E Airspace; Platinum, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... Class E airspace at Platinum AK (75 FR 77572). Interested parties were invited to participate in this... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Platinum, AK AGENCY:...

  7. 40 CFR Appendixes A-K to Part 51 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false A Appendixes A-K to Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Appendixes A-K to Part 51...

  8. 78 FR 14185 - Safety Zone; MODU KULLUK; Kiliuda Bay, Kodiak Island, AK to Captains Bay, Unalaska Island, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    .... SUPPLEMENTARY INFORMATION: ] Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; MODU KULLUK; Kiliuda Bay, Kodiak Island, AK to Captains Bay, Unalaska Island, AK AGENCY: Coast Guard, DHS. ACTION: Temporary final rule....

  9. Regional Mapping of Aortic Wall Stress by Using Deformable, Motion-coherent Modeling based on Electrocardiography-gated Multidetector CT Angiography: Feasibility Study.

    PubMed

    Mileto, Achille; Heye, Tobias J; Makar, Ryan A; Hurwitz, Lynne M; Marin, Daniele; Boll, Daniel T

    2016-07-01

    Purpose To investigate the feasibility of deformable, motion-coherent modeling based on electrocardiography-gated multidetector computed tomographic (CT) angiography of the thoracic aorta and to evaluate whether quantifiable information on aortic wall stress as a function of patient-specific cardiovascular parameters can be gained. Materials and Methods For this institutional review board-approved, HIPAA-compliant study, thoracic electrocardiography-gated dual-source multidetector CT angiographic images were used from 250 prospectively enrolled patients (150 men, 100 women; mean age, 79 years). On reconstructed 50-phase CT angiographic images, aortic strain and deformation were determined at seven cardiac and aortic locations. One-way analysis of variance was used by assessing the magnitude for longitudinal and axial strain and axial deformation, as well as time-resolved peak and maxima count for longitudinal strain and axial deformation. Interdependencies between aortic strain and deformation with extracted hemodynamic parameters were evaluated. Results With increasing heart rates, there was a significant decrease in longitudinal strain (P = .009, R(2) = 0.95) and a decrease in the number of longitudinal strain peaks (P < .001, R(2) = 0.79); however, a significant increase in axial deformation (P < .001, R(2) = 0.31) and axial strain (P = .009, R(2) = 0.61) was observed. Increasing aortic blood velocity led to increased longitudinal strain (P = .018, R(2) = 0.42) and longitudinal strain peak counts (P = .011, R(2) = 0.48). Pronounced motion in the longitudinal direction limited motion in the axial plane (P < .019, R(2) = 0.29-0.31). Conclusion The results of this study render a clinical basis and provide proof of principle for the use of deformable, motion-coherent modeling to provide quantitative information on physiological motion of the aorta under various hemodynamic circumstances. (©) RSNA, 2016 Online supplemental material is available for this article

  10. Cardiac Multidetector Computed Tomography: Basic Physics of Image Acquisition and Clinical Applications

    PubMed Central

    Bardo, Dianna M.E; Brown, Paul

    2008-01-01

    Cardiac MDCT is here to stay. And, it is more than just imaging coronary arteries. Understanding the differences in and the benefits of one CT scanner from another will help you to optimize the capabilities of the scanner, but requires a basic understanding of the MDCT imaging physics. This review provides key information needed to understand the differences in the types of MDCT scanners, from 64 – 320 detectors, flat panels, single and dual source configurations, step and shoot prospective and retrospective gating, and how each factor influences radiation dose, spatial and temporal resolution, and image noise. PMID:19936200

  11. Diagnosis of Variants of Single Right Coronary Trunk Using 64 Multidetector Computed Tomography

    PubMed Central

    Kempf, Ashley E.; Saremi, Farhood

    2008-01-01

    Single coronary anomalies are one of the rarest variants of coronary anatomy. Widespread use of coronary CT angiography has made it possible to diagnose these variants with increasing incidence. We report two cases of single right coronary trunk with different anatomic course of the left coronary artery; one anterior to the main pulmonary artery and the second between the main pulmonary artery and ascending aorta and then coursing within the interventricular septum. PMID:22470606

  12. Evaluation of cardiac function and myocardial viability with 16- and 64-slice multidetector computed tomography.

    PubMed

    Kopp, Andreas F; Heuschmid, Martin; Reimann, Anja; Kuettner, Axel; Beck, Thorsten; Ohmer, Martin; Burgstahler, Christoph; Brodoefel, Harald; Claussen, Claus D; Schroeder, Stephen

    2005-11-01

    Retrospectively ECG-gated MDCT shows a high correlation and acceptable agreement of left-ventricular functional parameters compared to MR imaging. Thus, in addition to the non-invasive evaluation of coronary arteries, further important additional information of left-ventricular functional parameters with clinical and prognostic relevance can be achieved by one single MDCT examination. For assessment of myocardial viability, low-dose CT late enhancement scanning is feasible, and preliminary results look promising. CT late enhancement adds valuable diagnostic information on the haemodynamical significance of coronary stenoses or prior to interventional procedures. PMID:16479639

  13. 97. View of International Business Machine (IBM) digital computer model ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    97. View of International Business Machine (IBM) digital computer model 7090 magnetic core installation, international telephone and telegraph (ITT) Artic Services Inc., Official photograph BMEWS site II, Clear, AK, by unknown photographer, 17 September 1965, BMEWS, clear as negative no. A-6604. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  14. 98. View of IBM digital computer model 7090 magnet core ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    98. View of IBM digital computer model 7090 magnet core installation. ITT Artic Services, Inc., Official photograph BMEWS Site II, Clear, AK, by unknown photographer, 17 September 1965. BMEWS, clear as negative no. A-6606. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  15. Comparison of Multidetector CT and Gadobutrol-Enhanced MR Imaging for Evaluation of Small, Solid Pancreatic Lesions

    PubMed Central

    Choi, Tae Won; Kim, Jung Hoon; Yu, Mi Hye; Han, Joon Koo; Choi, Byung Ihn

    2016-01-01

    Objective To compare multidetector computed tomography (MDCT) and MRI for lesion conspicuity, as well as the detection and characterization of small solid pancreatic lesions (SPLs). Materials and Methods 193 patients with small SPLs (< 3 cm) and 52 patients with normal pancreas who underwent both multiphasic MDCT and gadobutrol-enhanced MRI were included in our study. Two radiologists blinded to the pathologic diagnoses independently reviewed those images, and determined the detection of "SPL per se" and "SPL in consideration of secondary features", the lesion conspicuity, the probability of pancreatic ductal adenocarcinoma (PDAC), and the most likely specific diagnosis. Results The sensitivity of MRI for "detection of SPL per se" was significantly higher than that of CT in both reviewers: 92.7% (179/193) and 97.9% (189/193), respectively, for reviewer 1 (p = 0.031) and 90.7% (175/193) and 99.5% (192/193), respectively, for reviewer 2 (p < 0.001). In addition, MRI provided better lesion conspicuity than MDCT for both reviewers (p < 0.001). However, CT and MRI did not show significant difference in sensitivity for "detection of SPL in consideration of secondary features", specificity for SPL detection, and differentiation of PDAC vs. non-PDAC (p > 0.05). The accuracies of CT and MRI for making a specific diagnosis were as follows: 85.7% (210/245) vs. 86.9% (213/245), respectively, for reviewer 1 (p = 0.736), and 91.8% (225/245) vs. 93.5% (229/245), respectively, for reviewer 2 (p = 0.454). Conclusion MRI showed better lesion conspicuity than MDCT, but did not show significantly different diagnostic performance compared with MDCT for detecting and characterizing small SPLs. PMID:27390542

  16. The role of multidetector CT in local staging and evaluation of retroperitoneal surgical margin involvement in colon cancer

    PubMed Central

    Elibol, Funda Dinç; Obuz, Funda; Sökmen, Selman; Terzi, Cem; Canda, Aras Emre; Sağol, Özgül; Sarıoğlu, Sülen

    2016-01-01

    PURPOSE We aimed to evaluate preoperative T and N staging and retroperitoneal surgical margin (RSM) involvement in colon cancer using multidetector computed tomography (MDCT). METHODS In this retrospective study, preoperative MDCTs of 141 patients with colon adenocarcinoma were evaluated in terms of T and N staging and retroperitoneal surgical margin involvement by two observers. Results were compared with histopathology. RESULTS In determining extramural invasion, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MDCT were 81%, 50%, 95%, 26%, and 81% for observer 1 and 87%, 75%, 97%, 27%, and 84% for observer 2, respectively. Moderate interobserver agreement was observed (κ=0.425). In determining T stage of the tumor, accuracy of MDCT was 55% for observer 1 and 51% for observer 2. In the detection of lymph node metastasis, sensitivity, specificity, PPV, NPV, and accuracy of MDCT were 84%, 46%, 60%, 74% and 64% for observer 1 and 84%, 56%, 65%, 78%, and 70% for observer 2, respectively. Interobserver agreement was substantial (κ=0.650). RSM was involved in six cases (4.7%). When only retroperitoneal colon segments were considered, 1.6% of subjects demonstrated RSM involvement. Four of the six RSM-positive tumors were located on sigmoid colon and one tumor was on transverse colon and caecum. Considering all colon tumors, in the detection of RSM involvement, sensitivity and specificity of MDCT were 33% and 81% for observer 1 and 50% and 80% for observer 2. Interobserver agreement was moderate (κ=0.518). CONCLUSION MDCT is a promising technique with moderate interobserver agreement in detection of extramural invasion, lymph node metastases, and RSM involvement in colon carcinomas. PMID:26611110

  17. Multi-Detector Coronary CT Imaging for the Identification of Coronary Artery Stenoses in a “Real-World” Population

    PubMed Central

    Makaryus, Amgad N; Henry, Sonia; Loewinger, Lee; Makaryus, John N; Boxt, Lawrence

    2014-01-01

    BACKGROUND Multi-detector computed tomography (CT) has emerged as a modality for the non-invasive assessment of coronary artery disease (CAD). Prior studies have selected patients for evaluation and have excluded many of the “real-world” patients commonly encountered in daily practice. We compared 64-detector-CT (64-CT) to conventional coronary angiography (CA) to investigate the accuracy of 64-CT in determining significant coronary stenoses in a “real-world” clinical population. METHODS A total of 1,818 consecutive patients referred for 64-CT were evaluated. CT angiography was performed using the GE LightSpeed VCT (GE® Healthcare). Forty-one patients in whom 64-CT results prompted CA investigation were further evaluated, and results of the two diagnostic modalities were compared. RESULTS A total of 164 coronary arteries and 410 coronary segments were evaluated in 41 patients (30 men, 11 women, age 39–85 years) who were identified by 64-CT to have significant coronary stenoses and who thereafter underwent CA. The overall per-vessel sensitivity, specificity, positive predictive value, negative predictive value, and accuracy at the 50% stenosis level were 86%, 84%, 65%, 95%, and 85%, respectively, and 77%, 93%, 61%, 97%, and 91%, respectively, in the per-segment analysis at the 50% stenosis level. CONCLUSION 64-CT is an accurate imaging tool that allows a non-invasive assessment of significant CAD with a high diagnostic accuracy in a “real-world” population of patients. The sensitivity and specificity that we noted are not as high as those in prior reports, but we evaluated a population of patients that is typically encountered in clinical practice and therefore see more “real-world” results. PMID:25628513

  18. Nonalcoholic Hepatic Steatosis Is a Strong Predictor of High-Risk Coronary-Artery Plaques as Determined by Multidetector CT

    PubMed Central

    Osawa, Kazuhiro; Miyoshi, Toru; Yamauchi, Kentarou; Koyama, Yasushi; Nakamura, Kazufumi; Sato, Shuhei; Kanazawa, Susumu; Ito, Hiroshi

    2015-01-01

    Background Nonalcoholic fatty liver disease is associated with a risk of coronary artery disease (e.g., diabetes mellitus, dyslipidemia, metabolic syndrome). We evaluated whether nonalcoholic hepatic steatosis is associated with high-risk plaques as assessed by multidetector computed tomography (CT). Methods This retrospective study involved 414 participants suspected of having coronary artery disease. Nonalcoholic hepatic steatosis was defined as a liver-to-spleen fat ratio of <1.0 and the presence and appropriate characteristics of coronary-artery plaques as assessed by coronary CT angiography. High-risk plaques were identified, as were low-density plaques, positive remodeling, and spotty calcification. Results Compared with patients who did not have nonalcoholic hepatic steatosis, patients with nonalcoholic hepatic steatosis had more low-density plaques (21% vs. 44%, p<0.01), positive remodeling (41% vs. 58%, p = 0.01), and spotty calcification (12% vs. 36%, p<0.01). The number of high-risk plaques in patients with nonalcoholic hepatic steatosis was greater than in those without nonalcoholic hepatic steatosis (p<0.01). Patients with nonalcoholic hepatic steatosis were more likely to have high-risk plaques than were those with only an elevated level of visceral adipose tissue (≥86 cm2; 35% vs. 16%, p<0.01). Multivariate analyses that included nonalcoholic hepatic steatosis, amount of visceral adipose tissue, and the presence/absence of traditional risk factors demonstrated that nonalcoholic hepatic steatosis was an independent predictor of high-risk plaques (odds ratio: 4.60; 95% confidence interval: 1.94–9.07, p<0.01). Conclusions Diagnosis of nonalcoholic hepatic steatosis may be of value when assessing the risk of coronary artery disease. PMID:26125952

  19. 78 FR 55772 - Alaska Disaster Number AK-00028

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... From the Federal Register Online via the Government Publishing Office ] SMALL BUSINESS ADMINISTRATION Alaska Disaster Number AK-00028 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1... information in the original declaration remains unchanged. (Catalog of Federal Domestic Assistance...

  20. 75 FR 3641 - Television Broadcasting Services; Anchorage, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-22

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Anchorage, AK AGENCY: Federal Communications... broadcasting. 0 For the reasons discussed in the preamble, the Federal Communications Commission amends 47...

  1. The EINSTEIN-VARIĆAK Correspondence on Relativistic Rigid Rotation

    NASA Astrophysics Data System (ADS)

    Sauer, Tilman

    2008-09-01

    The historical significance of the problem of relativistic rigid rotation is reviewed in light of recently published correspondence between Einstein and the mathematician Vladimir Varićak from the years 1909 to 1913.

  2. Novel Wearable and Wireless Ring-Type Pulse Oximeter with Multi-Detectors

    PubMed Central

    Huang, Cheng-Yang; Chan, Ming-Che; Chen, Chien-Yue; Lin, Bor-Shyh

    2014-01-01

    The pulse oximeter is a popular instrument to monitor the arterial oxygen saturation (SPO2). Although a fingertip-type pulse oximeter is the mainstream one on the market at present, it is still inconvenient for long-term monitoring, in particular, with respect to motion. Therefore, the development of a wearable pulse oximeter, such as a finger base-type pulse oximeter, can effectively solve the above issue. However, the tissue structure of the finger base is complex, and there is lack of detailed information on the effect of the light source and detector placement on measuring SPO2. In this study, the practicability of a ring-type pulse oximeter with a multi-detector was investigated by optical human tissue simulation. The optimal design of a ring-type pulse oximeter that can provide the best efficiency of measuring SPO2 was discussed. The efficiency of ring-type pulse oximeters with a single detector and a multi-detector was also discussed. Finally, a wearable and wireless ring-type pulse oximeter was also implemented to validate the simulation results and was compared with the commercial fingertip-type pulse oximeter. PMID:25244586

  3. Monte Carlo simulations in multi-detector CT (MDCT) for two PET/CT scanner models using MASH and FASH adult phantoms

    NASA Astrophysics Data System (ADS)

    Belinato, W.; Santos, W. S.; Paschoal, C. M. M.; Souza, D. N.

    2015-06-01

    The combination of positron emission tomography (PET) and computed tomography (CT) has been extensively used in oncology for diagnosis and staging of tumors, radiotherapy planning and follow-up of patients with cancer, as well as in cardiology and neurology. This study determines by the Monte Carlo method the internal organ dose deposition for computational phantoms created by multidetector CT (MDCT) beams of two PET/CT devices operating with different parameters. The different MDCT beam parameters were largely related to the total filtration that provides a beam energetic change inside the gantry. This parameter was determined experimentally with the Accu-Gold Radcal measurement system. The experimental values of the total filtration were included in the simulations of two MCNPX code scenarios. The absorbed organ doses obtained in MASH and FASH phantoms indicate that bowtie filter geometry and the energy of the X-ray beam have significant influence on the results, although this influence can be compensated by adjusting other variables such as the tube current-time product (mAs) and pitch during PET/CT procedures.

  4. 75 FR 34624 - Revocation of Class D and E Airspace; Big Delta, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... airspace at Big Delta, AK (75 FR 17322). Controlled airspace serving Allen Army Airfield was revised in... TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Revocation of Class D and E Airspace; Big Delta, AK... Class D and E airspace at Big Delta, AK, to eliminate duplicated controlled airspace serving Allen...

  5. Usefulness of multidetector CT angiography for anomalous origin of coronary artery

    PubMed Central

    Ishisone, Takenori; Satoh, Mamoru; Okabayashi, Hitoshi; Nakamura, Motoyuki

    2014-01-01

    A 17-year-old man underwent clinical evaluation of exercise-induced syncope. Routine exercise stress test did not show any myocardial ischaemic changes or arrhythmias on the ECG recording. However, multidetector CT (MDCT) angiography of the coronary arteries revealed an abnormal origin of the left coronary artery from the right coronary sinus. The participants’ symptoms were diagnosed as cardiogenic syncope possibly due to transient stenosis of the left main coronary artery caught between the functionally distended aortic root and the pulmonary trunk during exercise. After successful patch coronary angioplasty, his symptoms disappeared completely even during a similar degree of strenuous exercise. It is important for clinicians not to overlook possible coronary artery anomalies during management of patients with exercise-induced syncope. MDCT coronary angiography may be a useful and non-invasive tool to establish diagnosis and a surgical approach to rectify congenital coronary artery anomalies. PMID:25150237

  6. Multidetector CT in emergency radiology: acute and generalized non-traumatic abdominal pain.

    PubMed

    Paolantonio, Pasquale; Rengo, Marco; Ferrari, Riccardo; Laghi, Andrea

    2016-05-01

    Multidetector CT (MDCT) is an imaging technique that provides otherwise unobtainable information in the diagnostic work-up of patients presenting with acute abdominal pain. A correct working diagnosis depends essentially on understanding the individual patient's clinical data and laboratory findings. In haemodynamically stable patients with acute severe and generalized abdominal pain, MDCT is now the preferred imaging test and gives invaluable diagnostic information, also in unstable patients after stabilization. In this descriptive review, we focus our attention on acute, severe and generalized or undifferentiated non-traumatic abdominal pain. The main differential diagnoses are acute pancreatitis, gastrointestinal perforation, ruptured abdominal aneurysm and acute mesenteric ischaemia. We will provide radiologist readers with a technical guide to optimize MDCT imaging protocols and list the major CT signs essential to reach a correct diagnosis and guide the best treatment. PMID:26689097

  7. Pulmonary arterial hypertension: an imaging review comparing MR pulmonary angiography and perfusion with multidetector CT angiography

    PubMed Central

    Junqueira, F P; Lima, C M A O; Coutinho, A C; Parente, D B; Bittencourt, L K; Bessa, L G P; Domingues, R C; Marchiori, E

    2012-01-01

    Pulmonary hypertension (PH) is a progressive disease that leads to substantial morbidity and eventual death. Pulmonary multidetector CT angiography (MDCTA), pulmonary MR angiography (MRA) and MR-derived pulmonary perfusion (MRPP) imaging are non-invasive imaging techniques for the differential diagnosis of PH. MDCTA is considered the gold standard for the diagnosis of pulmonary embolism, one of the most common causes of PH. MRA and MRPP are promising techniques that do not require the use of ionising radiation or iodinated contrast material, and can be useful for patients for whom such material cannot be used. This review compares the imaging aspects of pulmonary MRA and 64-row MDCTA in patients with chronic thromboembolic or idiopathic PH. PMID:22932061

  8. High resolution multidetector CT aided tissue analysis and quantification of lung fibrosis

    NASA Astrophysics Data System (ADS)

    Zavaletta, Vanessa A.; Karwoski, Ronald A.; Bartholmai, Brian; Robb, Richard A.

    2006-03-01

    Idiopathic pulmonary fibrosis (IPF, also known as Idiopathic Usual Interstitial Pneumontis, pathologically) is a progressive diffuse lung disease which has a median survival rate of less than four years with a prevalence of 15-20/100,000 in the United States. Global function changes are measured by pulmonary function tests and the diagnosis and extent of pulmonary structural changes are typically assessed by acquiring two-dimensional high resolution CT (HRCT) images. The acquisition and analysis of volumetric high resolution Multi-Detector CT (MDCT) images with nearly isotropic pixels offers the potential to measure both lung function and structure. This paper presents a new approach to three dimensional lung image analysis and classification of normal and abnormal structures in lungs with IPF.

  9. Multidetector CT angiography influences the choice of treatment for blunt carotid artery injury

    PubMed Central

    Beliaev, Andrei M; Civil, Ian

    2014-01-01

    A 43-year-old woman presented with a 2 h history of left neck pain after striking her neck against a marble bench while playing with her son. The patient was screened for blunt cerebrovascular injury (BCVI) and a left carotid bruit was identified. Subsequently, she underwent multidetector CT angiography (MCTA) of the aortic arch and neck vessels, which demonstrated a flow-limiting dissection of the left common carotid artery (CCA). The patient was started on heparin infusion and underwent an emergency operation. At surgery, a circumferential intimal dissection was excised and the arteriotomy defect closed with an autologous venous patch. This case emphasises the importance of adequately examining patients with direct injury to the neck, screening relevant patients for BCVI and investigating them with MCTA that influences the choice of a treatment option. PMID:25103313

  10. [Multidetector row CT in assessment of coronary artery calcification on hemodialisis].

    PubMed

    Caro, P; Delgado, R; Dapena, F; Núñez, A

    2007-01-01

    Vascular calcification is a strong predictor of cardiovascular and all-cause mortality. Coronary artery calcification is more frequent, more extensive and progresses more rapidly in CKD than in general population. They are also considered a marker of coronary heart disease, with high prevalence and functional significance. It suggests that detection and surveillance may be worthwhile in general clinical practice. New non-invasive image techniques, like Multi-detector row CT, a type of spiral scanner, assess density and volume of calcification at multiple sites and allow quantitative scoring of vascular calcification using calcium scores analogous to those from electron-beam CT. We have assessed and quantified coronary artery calcification with 16 multidetector row CT in 44 patients on hemodialysis and their relationship with several cardiovascular risk factors. Coronary artery calcification prevalence was of 84 % with mean calcium score of 1580 +/- 2010 ( r 0-9844) with calcium score > 400 in 66% of patients. It was usually multiple, affecting more than two vessels in more than 50%. In all but one patient, left anterior descending artery was involved with higher calcium score level at right coronary artery. Advanced age, male, diabetes, smoking, more morbidity, cerebrovascular disease previous, and calcium-binders phosphate and analogous vitamin D treatment would seem to be associated with coronary artery calcification. Coronary artery calcification is very frequent and extensive, usually multiple and associated to modifiable risk factors in hemodialysis patients. Multi-detector-row CT seems an effective, suitable, readily applicable method to assess and quantify coronary artery calcification. PMID:18336102

  11. Estimating radiation dose to organs of patients undergoing conventional and novel multidetector CT exams using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Angel, Erin

    Advances in Computed Tomography (CT) technology have led to an increase in the modality's diagnostic capabilities and therefore its utilization, which has in turn led to an increase in radiation exposure to the patient population. As a result, CT imaging currently constitutes approximately half of the collective exposure to ionizing radiation from medical procedures. In order to understand the radiation risk, it is necessary to estimate the radiation doses absorbed by patients undergoing CT imaging. The most widely accepted risk models are based on radiosensitive organ dose as opposed to whole body dose. In this research, radiosensitive organ dose was estimated using Monte Carlo based simulations incorporating detailed multidetector CT (MDCT) scanner models, specific scan protocols, and using patient models based on accurate patient anatomy and representing a range of patient sizes. Organ dose estimates were estimated for clinical MDCT exam protocols which pose a specific concern for radiosensitive organs or regions. These dose estimates include estimation of fetal dose for pregnant patients undergoing abdomen pelvis CT exams or undergoing exams to diagnose pulmonary embolism and venous thromboembolism. Breast and lung dose were estimated for patients undergoing coronary CTA imaging, conventional fixed tube current chest CT, and conventional tube current modulated (TCM) chest CT exams. The correlation of organ dose with patient size was quantified for pregnant patients undergoing abdomen/pelvis exams and for all breast and lung dose estimates presented. Novel dose reduction techniques were developed that incorporate organ location and are specifically designed to reduce close to radiosensitive organs during CT acquisition. A generalizable model was created for simulating conventional and novel attenuation-based TCM algorithms which can be used in simulations estimating organ dose for any patient model. The generalizable model is a significant contribution of this

  12. Characterizing string-of-pearls colloidal silica by multidetector hydrodynamic chromatography and comparison to multidetector size-exclusion chromatography, off-line multiangle static light scattering, and transmission electron microscopy.

    PubMed

    Brewer, Amandaa K; Striegel, André M

    2011-04-15

    The string-of-pearls-type morphology is ubiquitous, manifesting itself variously in proteins, vesicles, bacteria, synthetic polymers, and biopolymers. Characterizing the size and shape of analytes with such morphology, however, presents a challenge, due chiefly to the ease with which the "strings" can be broken during chromatographic analysis or to the paucity of information obtained from the benchmark microscopy and off-line light scattering methods. Here, we address this challenge with multidetector hydrodynamic chromatography (HDC), which has the ability to determine, simultaneously, the size, shape, and compactness and their distributions of string-of-pearls samples. We present the quadruple-detector HDC analysis of colloidal string-of-pearls silica, employing static multiangle and quasielastic light scattering, differential viscometry, and differential refractometry as detection methods. The multidetector approach shows a sample that is broadly polydisperse in both molar mass and size, with strings ranging from two to five particles, but which also contains a high concentration of single, unattached "pearls". Synergistic combination of the various size parameters obtained from the multiplicity of detectors employed shows that the strings with higher degrees of polymerization have a shape similar to the theory-predicted shape of a Gaussian random coil chain of nonoverlapping beads, while the strings with lower degrees of polymerization have a prolate ellipsoidal shape. The HDC technique is contrasted experimentally with multidetector size-exclusion chromatography, where, even under extremely gentle conditions, the strings still degraded during analysis. Such degradation is shown to be absent in HDC, as evidenced by the fact that the molar mass and radius of gyration obtained by HDC with multiangle static light scattering detection (HDC/MALS) compare quite favorably to those determined by off-line MALS analysis under otherwise identical conditions. The

  13. 77 FR 6463 - Amendment of Class E Airspace; Kwigillingok, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-08

    ...-2011-0881 was published in the Federal Register (77 FR 6), amending controlled airspace at Kwigillingok... published in the Federal Register on January 3, 2012 (77 FR 6), (FR Doc. 2011-33566), is corrected as... Administration 14 CFR Part 71 Amendment of Class E Airspace; Kwigillingok, AK AGENCY: Federal...

  14. 77 FR 5 - Amendment of Class E Airspace; Kipnuk, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ... Federal Register a notice of proposed rulemaking (NPRM) to amend controlled airspace at Kipnuk, AK (76 FR... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR.... 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in...

  15. 76 FR 60714 - Revision of Class E Airspace; Northway, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... proposed rulemaking (NPRM) in the Federal Register to revise Class E airspace at Northway, AK (76 FR 45475...: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389...; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034;...

  16. 78 FR 5128 - Amendment of Class E Airspace; Savoonga, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-24

    ... modify controlled airspace at Savoonga, AK (77 FR 61304). Interested parties were invited to participate... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of... read as follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR,...

  17. 75 FR 32269 - Revision of Class E Airspace; Wainwright, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-08

    ... rulemaking in the Federal Register to revise Class E airspace at Wainwright, AK (75 FR 11480). Interested...; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February... FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in 14 CFR...

  18. 76 FR 65944 - Establishment of Class E Airspace; Tatitlek, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... to establish Class E airspace at Tatitlek, AK (76 FR 49388). Interested parties were invited to... not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec....

  19. Ak-Chin Indian Community Biomass Feasiiblity Study

    SciTech Connect

    Mark A. Moser, RCM Digesters, Inc.; Mark Randall, Daystar Consulting, LLC; Leonard S. Gold, Ak-Chin Energy Services & Utility Strategies Consulting Group

    2005-12-31

    Study of the conversion of chicken litter to biogas for the production of energy. There was an additional requirement that after extracting the energy from the chicken litter the nutrient value of the raw chicken litter had to be returned to the Ak-Chin Farms for use as fertilizer in a form and delivery method acceptable to the Farm.

  20. 78 FR 4586 - Environmental Impact Statement: Kake Access, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-22

    ... Federal Highway Administration Environmental Impact Statement: Kake Access, AK ACTION: Notice of intent... issuing this notice to advise the public that FHWA will prepare an Environmental Impact Statement (EIS... Meetings will be held in the early Spring of 2013 to receive oral and written comments on...

  1. 77 FR 6 - Amendment of Class E Airspace; Kwigillingok, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ... follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp... controlled airspace at Kwigillingok, AK (76 FR 54151). Interested parties were invited to participate in this... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation...

  2. 76 FR 75447 - Amendment of Class E Airspace; Emmonak, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-02

    ... Federal Register a notice of proposed rulemaking (NPRM) to amend controlled airspace at Emmonak, AK (76 FR... 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034... FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in 14 CFR...

  3. 75 FR 33165 - Revision of Class E Airspace; Galena, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in 14 CFR 71.1... airspace at Galena, AK (75 FR 17892). Interested parties were invited to participate in this rulemaking... Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a regulatory...

  4. 78 FR 8962 - Establishment of Class E Airspace; Kasigluk, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-07

    ... rulemaking to modify controlled airspace at Kasigluk, AK (77 FR 60660). Interested parties were invited to... 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034..., 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The...

  5. 75 FR 62459 - Revision of Class E Airspace; Unalakleet, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... Federal Register to revise Class E airspace at Unalakleet, AK (75 FR 32865). Interested parties were...; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February.... 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 2. The incorporation by reference in 14...

  6. 76 FR 43823 - Revision of Class E Airspace; Yakutat, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Yakutat, AK AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action revises Class E airspace...

  7. 76 FR 8626 - Revision of Class E Airspace; Shungnak, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Shungnak, AK AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action revises Class E airspace...

  8. 76 FR 8624 - Revision of Class E Airspace; Barrow, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... revise Class E airspace at Barrow, Alaska (75 FR 71046). Interested parties were invited to participate..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Barrow, AK AGENCY:...

  9. 78 FR 59622 - Establishment of Class E Airspace; Akutan, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at..., Akutan, AK (78 FR 45477). Interested parties were invited to participate in this rulemaking effort by... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...

  10. 75 FR 11905 - Yukon Flats National Wildlife Refuge, Fairbanks, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ... or interests therein, from other willing sellers in other national wildlife refuges in Alaska, or to... Fish and Wildlife Service Yukon Flats National Wildlife Refuge, Fairbanks, AK AGENCY: U.S. Fish and... Wildlife Refuge final environmental impact statement. SUMMARY: We, the U.S. Fish and Wildlife...

  11. 76 FR 66178 - Revision of Class E Airspace; Umiat, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... proposed rulemaking (NPRM) in the Federal Register to revise Class E airspace at Umiat, AK (76 FR 49387... Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a regulatory evaluation.... 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in...

  12. 78 FR 16399 - Amendment of Class E Airspace; Unalakleet, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ... / Friday, March 15, 2013 / Rules and Regulations#0;#0; ] DEPARTMENT OF TRANSPORTATION Federal Aviation... (NPRM) to modify controlled airspace at Unalakleet, AK (77 FR 27149). Interested parties were invited to... Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of...

  13. 78 FR 45849 - Amendment of Class E Airspace; Gustavus, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-30

    ... Register a notice of proposed rulemaking (NPRM) to amend controlled airspace at Gustavus, AK (78 FR 31871... 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034...), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2....

  14. Synthetic streams in a gravitational wave inspiral search with a multidetector network

    NASA Astrophysics Data System (ADS)

    Haris, K.; Pai, Archana

    2014-07-01

    A gravitational wave inspiral search with a global network of interferometers when carried in a phase coherent fashion mimics a search with two effective synthetic data streams. The streams are constructed by the linear combination of the overwhitened data from individual detectors. We demonstrate here that the two synthetic data streams pertaining to the two polarizations of the gravitational wave can be derived prior to the maximum-likelihood analysis in a most natural way using the technique of singular-value decomposition applied to the network signal-to-noise ratio vector. The singular-value technique combined with the matched filtering in network plus spectral space enables the construction of the synthetic streams. We further show that the network log likelihood ratio is then the sum of the log-likelihood ratios of these synthetic streams. In this formalism, the four extrinsic parameters of the nonspinning inspiral signal, namely, amplitude, initial phase, binary inclination, and the polarization {A0,ϕa,ɛ ,Ψ}, are mapped to the two amplitudes and two phases, namely, {ρL,ρR,ΦL,ΦR}. We show that the maximization over the new extrinsic parameters is a straightforward exercise closely linked to the single detector approach in the literature. Toward the end, we connect all the previous works related to the multidetector gravitational wave inspiral search and present in the same notation.

  15. Recovery Act: Waste Energy Project at AK Steel Corporation Middletown

    SciTech Connect

    Joyce, Jeffrey

    2012-06-30

    In 2008, Air Products and Chemicals, Inc. (“Air Products”) began development of a project to beneficially utilize waste blast furnace “topgas” generated in the course of the iron-making process at AK Steel Corporation’s Middletown, Ohio works. In early 2010, Air Products was awarded DOE Assistance Agreement DE-EE002736 to further develop and build the combined-cycle power generation facility. In June 2012, Air Products and AK Steel Corporation terminated work when it was determined that the project would not be economically viable at that time nor in the foreseeable future. The project would have achieved the FOA-0000044 Statement of Project Objectives by demonstrating, at a commercial scale, the technology to capture, treat, and convert blast furnace topgas into electric power and thermal energy.

  16. A method of estimating conceptus doses resulting from multidetector CT examinations during all stages of gestation

    SciTech Connect

    Damilakis, John; Tzedakis, Antonis; Perisinakis, Kostas; Papadakis, Antonios E.

    2010-12-15

    Purpose: Current methods for the estimation of conceptus dose from multidetector CT (MDCT) examinations performed on the mother provide dose data for typical protocols with a fixed scan length. However, modified low-dose imaging protocols are frequently used during pregnancy. The purpose of the current study was to develop a method for the estimation of conceptus dose from any MDCT examination of the trunk performed during all stages of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study to model the Siemens Sensation 16 and Sensation 64 MDCT scanners. Four mathematical phantoms were used, simulating women at 0, 3, 6, and 9 months of gestation. The contribution to the conceptus dose from single simulated scans was obtained at various positions across the phantoms. To investigate the effect of maternal body size and conceptus depth on conceptus dose, phantoms of different sizes were produced by adding layers of adipose tissue around the trunk of the mathematical phantoms. To verify MCNP results, conceptus dose measurements were carried out by means of three physical anthropomorphic phantoms, simulating pregnancy at 0, 3, and 6 months of gestation and thermoluminescence dosimetry (TLD) crystals. Results: The results consist of Monte Carlo-generated normalized conceptus dose coefficients for single scans across the four mathematical phantoms. These coefficients were defined as the conceptus dose contribution from a single scan divided by the CTDI free-in-air measured with identical scanning parameters. Data have been produced to take into account the effect of maternal body size and conceptus position variations on conceptus dose. Conceptus doses measured with TLD crystals showed a difference of up to 19% compared to those estimated by mathematical simulations. Conclusions: Estimation of conceptus doses from MDCT examinations of the trunk performed on pregnant patients during all stages of gestation can be made

  17. Computed Tomography Angiography of the Small Bowel and Mesentery.

    PubMed

    Raman, Siva P; Fishman, Elliot K

    2016-01-01

    Multidetector computed tomography (MDCT) has largely supplanted other available radiologic modalities in the evaluation of a wide variety of different vascular and inflammatory abnormalities of the small bowel, with computed tomography angiography (CTA) playing a major role in the diagnostic efficacy of MDCT for these diseases. Improvements in CTA imaging have proved particularly valuable in the evaluation of small bowel vascular and inflammatory disorders, diagnoses in which arterial phase images might be able to offer greater information than standard venous phase imaging. This article details the MDCT imaging findings of several small bowel vascular and inflammatory disorders. PMID:26654393

  18. 39. View of checkout indicator computer console for DR beams, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. View of checkout indicator computer console for DR beams, TR chains, and special checkout target control located in CSMR in transmitter building no. 102. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  19. Efficient Activation of Apoptotic Signaling during Mitotic Arrest with AK301

    PubMed Central

    Bleiler, Marina; Yeagley, Michelle; Wright, Dennis; Giardina, Charles

    2016-01-01

    Mitotic inhibitors are widely utilized chemotherapeutic agents that take advantage of mitotic defects in cancer cells. We have identified a novel class of piperazine-based mitotic inhibitors, of which AK301 is the most potent derivative identified to date (EC50 < 200 nM). Colon cancer cells arrested in mitosis with AK301 readily underwent a p53-dependent apoptosis following compound withdrawal and arrest release. This apoptotic response was significantly higher for AK301 than for other mitotic inhibitors tested (colchicine, vincristine, and BI 2536). AK301-treated cells exhibited a robust mitosis-associated DNA damage response, including ATM activation, γH2AX phosphorylation and p53 stabilization. The association between mitotic signaling and the DNA damage response was supported by the finding that Aurora B inhibition reduced the level of γH2AX staining. Confocal imaging of AK301-treated cells revealed multiple γ-tubulin microtubule organizing centers attached to microtubules, but with limited centrosome migration, raising the possibility that aberrant microtubule pulling may underlie DNA breakage. AK301 selectively targeted APC-mutant colonocytes and promoted TNF-induced apoptosis in p53-mutant colon cancer cells. Our findings indicate that AK301 induces a mitotic arrest state with a highly active DNA damage response. Together with a reversible arrest state, AK301 is a potent promoter of a mitosis-to-apoptosis transition that can target cancer cells with mitotic defects. PMID:27097159

  20. Reticular dysgenesis–associated AK2 protects hematopoietic stem and progenitor cell development from oxidative stress

    PubMed Central

    Rissone, Alberto; Weinacht, Katja Gabriele; la Marca, Giancarlo; Bishop, Kevin; Giocaliere, Elisa; Jagadeesh, Jayashree; Felgentreff, Kerstin; Dobbs, Kerry; Al-Herz, Waleed; Jones, Marypat; Chandrasekharappa, Settara; Kirby, Martha; Wincovitch, Stephen; Simon, Karen Lyn; Itan, Yuval; DeVine, Alex; Schlaeger, Thorsten; Schambach, Axel; Sood, Raman

    2015-01-01

    Adenylate kinases (AKs) are phosphotransferases that regulate the cellular adenine nucleotide composition and play a critical role in the energy homeostasis of all tissues. The AK2 isoenzyme is expressed in the mitochondrial intermembrane space and is mutated in reticular dysgenesis (RD), a rare form of severe combined immunodeficiency (SCID) in humans. RD is characterized by a maturation arrest in the myeloid and lymphoid lineages, leading to early onset, recurrent, and overwhelming infections. To gain insight into the pathophysiology of RD, we studied the effects of AK2 deficiency using the zebrafish model and induced pluripotent stem cells (iPSCs) derived from fibroblasts of an RD patient. In zebrafish, Ak2 deficiency affected hematopoietic stem and progenitor cell (HSPC) development with increased oxidative stress and apoptosis. AK2-deficient iPSCs recapitulated the characteristic myeloid maturation arrest at the promyelocyte stage and demonstrated an increased AMP/ADP ratio, indicative of an energy-depleted adenine nucleotide profile. Antioxidant treatment rescued the hematopoietic phenotypes in vivo in ak2 mutant zebrafish and restored differentiation of AK2-deficient iPSCs into mature granulocytes. Our results link hematopoietic cell fate in AK2 deficiency to cellular energy depletion and increased oxidative stress. This points to the potential use of antioxidants as a supportive therapeutic modality for patients with RD. PMID:26150473

  1. 78 FR 30797 - Proposed Amendment of Class E Airspace; Point Thomson, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ...This action proposes to modify the airspace at Point Thomson, AK by establishing Class E Airspace at Point Thomson Airstrip Airport, Point Thomson, AK. This will accommodate aircraft using a new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at the airport. The FAA is proposing this action to enhance the safety and management of aircraft......

  2. Statistical iterative reconstruction for streak artefact reduction when using multidetector CT to image the dento-alveolar structures

    PubMed Central

    Hayakawa, Y; Kober, C

    2014-01-01

    Objectives: When metallic prosthetic appliances and dental fillings exist in the oral cavity, the appearance of metal-induced streak artefacts is not avoidable in CT images. The aim of this study was to develop a method for artefact reduction using the statistical reconstruction on multidetector row CT images. Methods: Adjacent CT images often depict similar anatomical structures. Therefore, reconstructed images with weak artefacts were attempted using projection data of an artefact-free image in a neighbouring thin slice. Images with moderate and strong artefacts were continuously processed in sequence by successive iterative restoration where the projection data was generated from the adjacent reconstructed slice. First, the basic maximum likelihood–expectation maximization algorithm was applied. Next, the ordered subset–expectation maximization algorithm was examined. Alternatively, a small region of interest setting was designated. Finally, the general purpose graphic processing unit machine was applied in both situations. Results: The algorithms reduced the metal-induced streak artefacts on multidetector row CT images when the sequential processing method was applied. The ordered subset–expectation maximization and small region of interest reduced the processing duration without apparent detriments. A general-purpose graphic processing unit realized the high performance. Conclusions: A statistical reconstruction method was applied for the streak artefact reduction. The alternative algorithms applied were effective. Both software and hardware tools, such as ordered subset–expectation maximization, small region of interest and general-purpose graphic processing unit achieved fast artefact correction. PMID:24754471

  3. Some aspects of the effects of PL-10.1.AK-15 on the gastrointestinal tract.

    PubMed

    Erceg, D; Simicevic, V N; Kolega, M; Dohoczky, C

    1997-01-01

    PL-10.1.AK-15 is an active fragment of a naturally occurring protein first isolated from human gastric juice. Among its other protective effects, PL-10.1.AK-15 has demonstrated a protective effect on the gastrointestinal tract. The aim of this study was to investigate the influence of PL-10.1.AK-15 on two functional parameters of gastrointestinal function: gastric acid secretion and gastrointestinal motility. Gastric acid secretion was assessed in male Wistar rats using a modified method of Shay, while gastrointestinal motility was assessed in male NMRI mice by charcoal propulsion. PL-10.1.AK-15 was given in three different doses (3, 10 and 100 micrograms/kg body weight) in accordance with the experimental protocol. The results of these experiments indicate that PL-10.1.AK-15 in the investigated doses had no influence on gastric acid secretion or gastrointestinal motility. PMID:9403791

  4. Absorbed Radiation Dose in Radiosensitive Organs Using 64- and 320-Row Multidetector Computed Tomography: A Comparative Study

    PubMed Central

    Khan, Atif N.; Nikolic, Boris; Khan, Mohammad K.; Kang, Jian; Khosa, Faisal

    2014-01-01

    Aim. To determine absorbed radiation dose (ARD) in radiosensitive organs during prospective and full phase dose modulation using ECG-gated MDCTA scanner under 64- and 320-row detector modes. Methods. Female phantom was used to measure organ radiation dose. Five DP-3 radiation detectors were used to measure ARD to lungs, breast, and thyroid using the Aquilion ONE scanner in 64- and 320-row modes using both prospective and dose modulation in full phase acquisition. Five measurements were made using three tube voltages: 100, 120, and 135 kVp at 400 mA at heart rate (HR) of 60 and 75 bpm for each protocol. Mean acquisition was recorded in milligrays (mGy). Results. Mean ARD was less for 320-row versus 64-row mode for each imaging protocol. Prospective EKG-gated imaging protocol resulted in a statistically lower ARD using 320-row versus 64-row modes for midbreast (6.728 versus 19.687 mGy, P < 0.001), lung (6.102 versus 21.841 mGy, P < 0.001), and thyroid gland (0.208 versus 0.913 mGy; P < 0.001). Retrospective imaging using 320- versus 64-row modes showed lower ARD for midbreast (10.839 versus 43.169 mGy, P < 0.001), lung (8.848 versus 47.877 mGy, P < 0.001), and thyroid gland (0.057 versus 2.091 mGy; P < 0.001). ARD reduction was observed at lower kVp and heart rate. Conclusions. Dose reduction to radiosensitive organs is achieved using 320-row compared to 64-row modes for both prospective and retrospective gating, whereas 64-row mode is equivalent to the same model 64-row MDCT scanner. PMID:25170427

  5. Stereological estimation of left-ventricular volumetric and functional parameters from multidetector-row computed tomography data.

    PubMed

    Mazonakis, Michalis; Pagonidis, Konstantin; Schlosser, Thomas; Hunold, Peter; Damilakis, John; Barkhausen, Jörg; Gourtsoyiannis, Nicholas

    2008-07-01

    This study aims to optimize the stereological method for estimating left-ventricular (LV) parameters from retrospectively electrocardiography-gated 16-row MDCT and to compare stereological estimations with those by MRI. MDCT was performed in 17 consecutive patients with known or suspected coronary disease. Stereological measurements based on point counting were optimized by determining the appropriate distance between grid points. LV parameters were evaluated by standard CT analysis using a semi-automatic segmentation method. Two independent observers evaluated the reproducibility of the stereological method. End-diastolic volume (EDV) and end-systolic volume (ESV) estimations with a coefficient of error below 5% were obtained in a mean time of 2.3 +/- 0.5 min with a point spacing of 25 and 15 pixels, respectively. The intra- and interobserver variability for estimating LV parameters was 2.6-4.4 and 4.9-8.2%, respectively. MRI estimations were highly correlated with those by standard CT analysis (R > 0.82) and stereology (R > 0.84). Stereological method significantly overestimated EDV and ESV compared to MRI (EDV: P = 0.0011; ESV: P = 0.0013), whereas for stroke volume (SV) and ejection fraction (EF), no difference was observed (P > 0.05). For standard CT analysis and MRI, significant differences were found except for SV and EF (EDV: P = 0.0008; ESV: P = 0.0004; EF: P = 0.051; SV: P = 0.064). The time-efficient optimized stereological method enables the reproducible evaluation of LV function from MDCT. PMID:18351349

  6. Multidetector CT Findings and Differential Diagnoses of Malignant Pleural Mesothelioma and Metastatic Pleural Diseases in Korea

    PubMed Central

    Kim, Yoon Kyung; Lee, Kyung Won; Yi, Chin A; Koo, Jin Mo; Jung, Soon-Hee

    2016-01-01

    Objective To compare the multidetector CT (MDCT) features of malignant pleural mesothelioma (MPM) and metastatic pleural disease (MPD). Materials and Methods The authors reviewed the MDCT images of 167 patients, 103 patients with MPM and 64 patients with MPD. All 167 cases were pathologically confirmed by sonography-guided needle biopsy of pleura, thoracoscopic pleural biopsy, or open thoracotomy. CT features were evaluated with respect to pleural effusion, pleural thickening, invasion of other organs, lung abnormality, lymphadenopathy, mediastinal shifting, thoracic volume decrease, asbestosis, and the presence of pleural plaque. Results Pleural thickening was the most common CT finding in MPM (96.1%) and MPD (93.8%). Circumferential pleural thickening (31.1% vs. 10.9%, odds ratio [OR] 3.670), thickening of fissural pleura (83.5% vs. 67.2%, OR 2.471), thickening of diaphragmatic pleura (90.3% vs. 73.4%, OR 3.364), pleural mass (38.8% vs. 23.4%, OR 2.074), pericardial involvement (56.3% vs. 20.3%, OR 5.056), and pleural plaque (66.0% vs. 21.9%, OR 6.939) were more frequently seen in MPM than in MPD. On the other hand, nodular pleural thickening (59.2% vs. 76.6%, OR 0.445), hilar lymph node metastasis (5.8% vs. 20.3%, OR 0.243), mediastinal lymph node metastasis (10.7% vs. 37.5%, OR 0.199), and hematogenous lung metastasis (9.7% vs. 29.2%, OR 0.261) were less frequent in MPM than in MPD. When we analyzed MPD from extrathoracic malignancy (EMPD) separately and compared them to MPM, circumferential pleural thickening, thickening of interlobar fissure, pericardial involvement and presence of pleural plaque were significant findings indicating MPM than EMPD. MPM had significantly lower occurrence of hematogenous lung metastasis, as compared with EMPD. Conclusion Awareness of frequent and infrequent CT findings could aid in distinguishing MPM from MPD. PMID:27390546

  7. Decolorization of sulfonated azo dye Metanil Yellow by newly isolated bacterial strains: Bacillus sp. strain AK1 and Lysinibacillus sp. strain AK2.

    PubMed

    Anjaneya, O; Souche, S Yogesh; Santoshkumar, M; Karegoudar, T B

    2011-06-15

    Two different bacterial strains capable of decolorizing a highly water soluble azo dye Metanil Yellow were isolated from dye contaminated soil sample collected from Atul Dyeing Industry, Bellary, India. The individual bacterial strains Bacillus sp. AK1 and Lysinibacillus sp. AK2 decolorized Metanil Yellow (200 mg L(-1)) completely within 27 and 12h respectively. Various parameters like pH, temperature, NaCl and initial dye concentrations were optimized to develop an economically feasible decolorization process. The maximum concentration of Metanil Yellow (1000 mg L(-1)) was decolorized by strains AK2 and AK1 within 78 and 84 h respectively. These strains could decolorize Metanil Yellow over a broad pH range 5.5-9.0; the optimum pH was 7.2. The decolorization of Metanil Yellow was most efficient at 40°C and confirmed by UV-visible spectroscopy, TLC, HPLC and GC/MS analysis. Further, both the strains showed the involvement of azoreductase in the decolorization process. Phytotoxicity studies of catabolic products of Metanil Yellow on the seeds of chick pea and pigeon pea revealed much reduction in the toxicity of metabolites as compared to the parent dye. These results indicating the effectiveness of strains AK1 and AK2 for the treatment of textile effluents containing azo dyes. PMID:21470774

  8. A Photometric Study of the Misclassified Variable AK Ursae Minoris

    NASA Astrophysics Data System (ADS)

    Dale, H.; Sgro, L. A., Jr.

    2015-07-01

    The star AK UMi [GSC 4656-0461] was originally misidentified as an RRc-Lyrae pulsating variable by analyzing undersampled survey data. We used greater time resolved differential photometry to positively identify this variable as a W UMa overcontact (subtype A) binary system. The secondary minimum is a total eclipse, which enabled us to approximate the model for this system using some well-known characteristics of overcontact binaries. Our model solution parameters were found to be: i = 90˚, q = 0.21 (M2/M1), and T1 = 6750K, which indicated that the primary should be an F4.

  9. High Level Expression and Purification of Recombinant Proteins from Escherichia coli with AK-TAG

    PubMed Central

    Luo, Dan; Wen, Caixia; Zhao, Rongchuan; Liu, Xinyu; Liu, Xinxin; Cui, Jingjing; Liang, Joshua G.; Liang, Peng

    2016-01-01

    Adenylate kinase (AK) from Escherichia coli was used as both solubility and affinity tag for recombinant protein production. When fused to the N-terminus of a target protein, an AK fusion protein could be expressed in soluble form and purified to near homogeneity in a single step from Blue-Sepherose via affinity elution with micromolar concentration of P1, P5- di (adenosine—5’) pentaphosphate (Ap5A), a transition-state substrate analog of AK. Unlike any other affinity tags, the level of a recombinant protein expression in soluble form and its yield of recovery during each purification step could be readily assessed by AK enzyme activity in near real time. Coupled to a His-Tag installed at the N-terminus and a thrombin cleavage site at the C terminus of AK, the streamlined method, here we dubbed AK-TAG, could also allow convenient expression and retrieval of a cleaved recombinant protein in high yield and purity via dual affinity purification steps. Thus AK-TAG is a new addition to the arsenal of existing affinity tags for recombinant protein expression and purification, and is particularly useful where soluble expression and high degree of purification are at stake. PMID:27214237

  10. Cardiac sarcoidosis evaluated with gadolinium-enhanced magnetic resonance and contrast-enhanced 64-slice computed tomography.

    PubMed

    Smedema, Jan-Peter; Truter, Rene; de Klerk, Petra A; Zaaiman, Leonie; White, Leonie; Doubell, Anton F

    2006-09-20

    Sarcoidosis is a multi-system granulomatous disorder of unknown etiology with symptomatic cardiac involvement in up to 7% of patients. The clinical features of sarcoid heart disease include congestive heart failure, arrhythmias, conduction disturbances, and sudden death. We evaluated the value of contrast-enhanced multi-detector computed tomography in delineating myocardial scar and granulomatous inflammation by comparing our findings with gadolinium magnetic resonance in a patient diagnosed with cardiac sarcoidosis. PMID:16257460

  11. Pulmonary multislice computed tomography findings in acute aortic dissection

    PubMed Central

    Okur, Aysegul; Sahin, Sinan

    2012-01-01

    Objective To document the type and incidence of pulmonary multislice computed tomography (CT) findings at presentation in patients with acute aortic dissection. Materials and methods Multidetector CT scans of 36 patients with a diagnosis of acute aortic dissection or intramural hematoma were retrospectively reviewed. Results Pleural effusion, dependent stasis, mosaic attenuation, interlobular septal thickening, thickening of the peribronchovascular interstitium, vascular enlargement, compression atelectasis were common findings. Additionally air trapping, emphysema, consolidation, nodules, bronchiectasis or scarring were also noted. Conclusions Various pulmonary imaging findings may accompany acute aortic dissection. These findings and their clinical significance should be further investigated. PMID:23050112

  12. Computed Tomography Angiography of the Hepatic, Pancreatic, and Splenic Circulation.

    PubMed

    Price, Melissa; Patino, Manuel; Sahani, Dushyant

    2016-01-01

    Multidetector computed tomography angiography (MDCTA) has become a routine imaging tool to assess visceral vascular anatomy and abdominal parenchymal pathology. Enhanced temporal resolution and rapid acquisition allow for precise delineation of arterial and venous anatomy. The excellent spatial resolution permits assessment of small parenchyma lesions and vasculature. The ability of CT to rapidly acquire data and reconstruct with thinner slices allows robust 3D mapping using maximum intensity projection before definitive surgical or interventional therapy. Emerging novel techniques of image acquisition offer sensitive methods for detecting enhancement and allow for virtual imaging subtraction, all while limiting the total radiation burden. PMID:26654391

  13. Virtual Monochromatic Images from Dual-Energy Multidetector CT: Variance in CT Numbers from the Same Lesion between Single-Source Projection-based and Dual-Source Image-based Implementations.

    PubMed

    Mileto, Achille; Barina, Andrew; Marin, Daniele; Stinnett, Sandra S; Roy Choudhury, Kingshuk; Wilson, Joshua M; Nelson, Rendon C

    2016-04-01

    Purpose To determine the variance in virtual monochromatic computed tomography (CT) numbers from the same lesion, comparing the two clinically available dual-energy multidetector CT hardware implementations (single-source projection-based and dual-source image-based), in a phantom-based simulated abdominal environment. Materials and Methods This phantom-based study was exempt from institutional review board oversight. Polyethylene terephthalate spheres (15 and 18 mm) with two iodine-to-saline dilutions (0.8 and 1.2 mg of iodine per millilliter) were serially suspended in a cylindrical polypropylene bottle filled with diluted iodinated contrast material. The bottle was placed into a 36-cm-wide torso-shaped water phantom simulating the abdomen of a medium-sized patient. Dual-energy (80/140 kVp) and single-energy (100 and 120 kVp) scans were obtained with single-source and dual-source multidetector CT implementations. Virtual monochromatic images were reconstructed at energy levels of 40-140 keV (in 10-keV increments) in either the projection-space or image-space domain. A multivariate regression analysis approach was used to investigate the effect of energy level, lesion size, lesion iodine content, and implementation type on measured CT numbers. Results There were significant differences in the attenuation values measured in the simulated lesions with the single-source projection-based platform and the dual-source image-based implementation (P < .001 for all comparisons). The magnitude of these differences was greatest at lower monochromatic energy levels and at lower iodine concentrations (average difference at 40 keV: 25.7 HU; average difference at 140 keV: 7 HU). The monochromatic energy level and the lesion iodine concentration had a significant effect on the difference in the measured attenuation values between the two implementations, which indicates that the two imaging platforms respond differently to changes in investigated variables (P < .001 for all

  14. 75 FR 5145 - AK Steel Corporation, Mansfield Works Division, Mansfield, OH; Notice of Affirmative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration AK Steel Corporation, Mansfield Works Division, Mansfield, OH; Notice of Affirmative Determination Regarding Application for Reconsideration By application dated...

  15. Photometric analysis of overcontact binaries AK Her, HI Dra, V1128 Tau, and V2612 Oph

    SciTech Connect

    Çalışkan, Ş.; Özavcı, İ.; Baştürk, Ö.; Şenavcı, H. V.; Kılıçoğlu, T.; Yılmaz, M.; Selam, S. O.; Latković, O.; Djurašević, G.; Cséki, A. E-mail: ozavci@science.ankara.edu.tr E-mail: hvsenavci@ankara.edu.tr E-mail: mesutyilmaz@ankara.edu.tr E-mail: olivia@aob.rs E-mail: attila@aob.rs

    2014-12-01

    We analyze new, high quality multicolor light curves of four overcontact binaries: AK Her, HI Dra, V1128 Tau, and V2612 Oph, and determine their orbital and physical parameters using the modeling program of G. Djurasevic and recently published results of radial velocity studies. The achieved precision in absolute masses is between 10% and 20%, and the precision in absolute radii is between 5% and 10%. All four systems are W UMa-type binaries with bright or dark spots indicative of mass and energy transfer or surface activity. We estimate the distances and the ages of the systems using the luminosities computed through our analysis, and perform an O – C study for V1128 Tau, which reveals a complex period variation that can be interpreted in terms of mass loss/exchange and either the presence of the third body, or the magnetic activity on one of the components. We conclude that further observations of these systems are needed to deepen our understanding of their nature and variability.

  16. Improving Image Quality of On-Board Cone-Beam CT in Radiation Therapy Using Image Information Provided by Planning Multi-Detector CT: A Phantom Study

    PubMed Central

    Yang, Ching-Ching; Chen, Fong-Lin; Lo, Yeh-Chi

    2016-01-01

    Purpose The aim of this study was to improve the image quality of cone-beam computed tomography (CBCT) mounted on the gantry of a linear accelerator used in radiation therapy based on the image information provided by planning multi-detector CT (MDCT). Methods MDCT-based shading correction for CBCT and virtual monochromatic CT (VMCT) synthesized using the dual-energy method were performed. In VMCT, the high-energy data were obtained from CBCT, while the low-energy data were obtained from MDCT. An electron density phantom was used to investigate the efficacy of shading correction and VMCT on improving the target detectability, Hounsfield unit (HU) accuracy and variation, which were quantified by calculating the contrast-to-noise ratio (CNR), the percent difference (%Diff) and the standard deviation of the CT numbers for tissue equivalent background material, respectively. Treatment plan studies for a chest phantom were conducted to investigate the effects of image quality improvement on dose planning. Results For the electron density phantom, the mean value of CNR was 17.84, 26.78 and 34.31 in CBCT, shading-corrected CBCT and VMCT, respectively. The mean value of %Diff was 152.67%, 11.93% and 7.66% in CBCT, shading-corrected CBCT and VMCT, respectively. The standard deviation within a uniform background of CBCT, shading-corrected CBCT and VMCT was 85, 23 and 15 HU, respectively. With regards to the chest phantom, the monitor unit (MU) difference between the treatment plan calculated using MDCT and those based on CBCT, shading corrected CBCT and VMCT was 6.32%, 1.05% and 0.94%, respectively. Conclusions Enhancement of image quality in on-board CBCT can contribute to daily patient setup and adaptive dose delivery, thus enabling higher confidence in patient treatment accuracy in radiation therapy. Based on our results, VMCT has the highest image quality, followed by the shading corrected CBCT and the original CBCT. The research results presented in this study should be

  17. Angular on-line tube current modulation in multidetector CT examinations of children and adults: The influence of different scanning parameters on dose reduction

    SciTech Connect

    Papadakis, Antonios E.; Perisinakis, Kostas; Damilakis, John

    2007-07-15

    The purpose of this study was to assess the potential of angular on-line tube current modulation on dose reduction in pediatric and adult patients undergoing multidetector computed tomography (MDCT) examinations. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-year-old, 5-year-old, 10-year-old, and adult were employed in the current study. Phantoms were scanned with the use of on-line tube current modulation (TCM). Percent dose reduction (%DR) factors achieved by applying TCM, were determined for standard protocols used for head and neck, shoulder, thorax, thorax and abdomen, abdomen, abdomen and pelvis, pelvis, and whole body examinations. A preliminary study on the application of TCM in MDCT examinations of adult patients was performed to validate the results obtained in anthropomorphic phantoms. Dose reduction was estimated as the percentage difference of the modulated milliamperes for each scan and the preset milliamperes prescribed by the scan protocol. The dose reduction in children was found to be much lower than the corresponding reduction achieved for adults. For helical scans the %DR factors, ranged between 1.6% and 7.4% for the neonate, 2.9% and 8.7% for the 1-year old, 2% and 6% for the 5-year-old, 5% and 10.9% for the 10-year-old, and 10.4% and 20.7% for the adult individual. For sequential scans the corresponding %DR factors ranged between 1.3% and 6.7%, 4.5% and 11%, 4.2% and 6.6%, 6.4% and 12.3%, and 8.9% and 23.3%, respectively. Broader beam collimations are associated with decreased %DR factors, when other scanning parameters are held constant. TCM did not impair image noise. In adult patients, the %DR values were found to be in good agreement with the corresponding results obtained in the anthropomorphic adult phantom. In conclusion, on-line TCM may be considered as a valuable tool for reducing dose in routine CT examinations of pediatric and adult patients. However, the dose reduction achieved with TCM

  18. Results from ORNL characterization of ZrO2-500-AK2 - surrogate TRISO material

    SciTech Connect

    Kercher, Andrew K; Hunn, John D

    2005-06-01

    This document is a compilation of the characterization data for the TRISO-coated surrogate particles designated ZrO2-500-AK2 that was produced at Oak Ridge National Laboratory (ORNL) as part of the Advanced Gas Reactor Fuel Development and Qualification (AGR) program. The ZrO2-500-AK2 material contains nominally 500 {micro}m kernels of yttria-stabilized zirconia (YSZ) coated with all TRISO layers (buffer, inner pyrocarbon, silicon carbide, and outer pyrocarbon). The ZrO2-500-AK2 material was created for: (1) irradiation testing in the High Flux Isotope Reactor (HFIR) and (2) limited dissemination to laboratories as deemed appropriate to the AGR program. This material was created midway into a TRISO fuel development program to accommodate a sudden opportunity to perform irradiation testing on surrogate material. While the layer deposition processes were chosen based on the best technical understanding at the time, technical progress at ORNL has led to an evolution in the perceived optimal deposition conditions since the creation of ZrO2-500-AK2. Thus, ZrO2-500-AK2 contains a reasonable TRISO microstructure, but does differ significantly from currently produced TRISO surrogates and fuel at ORNL. In this document, characterization data of the ZrO2-500-AK2 surrogate includes: size, shape, coating thickness, and density.

  19. Results from ORNL Characterization of Zr02-500-AK2 - Surrogate TRISO Material

    SciTech Connect

    Hunn, John D; Kercher, Andrew K

    2005-06-01

    This document is a compilation of the characterization data for the TRISO-coated surrogate particle batch designated ZrO2-500-AK2 that was produced at Oak Ridge National Laboratory (ORNL) as part of the Advanced Gas Reactor Fuel Development and Qualification (AGR) program. The ZrO2-500-AK2 material contains nominally 500 {micro}m kernels of yttria-stabilized zirconia (YSZ) coated with all TRISO layers (buffer, inner pyrocarbon, silicon carbide, and outer pyrocarbon). The ZrO2-500-AK2 material was created for: (1) irradiation testing in the High Flux Isotope Reactor (HFIR) and (2) limited dissemination to laboratories as deemed appropriate to the AGR program. This material was created midway into a TRISO fuel development program to accommodate a sudden opportunity to perform irradiation testing on surrogate material. While the layer deposition processes were chosen based on the best technical understanding at the time, technical progress at ORNL has led to an evolution in the perceived optimal deposition conditions since the createion of ZrO2-500-AK2. Thus, ZrO2-500-AK2 contains a reasonable TRISO microstructure, but does differ significanly from currently produced TRISO surrogates and fuel at ORNL. In this document, characterization data of the ZrO2-500-AK2 surrogate includes: size, shape, coating thickness, and density.

  20. Three-Dimensional Endo-Cardiovascular Volume-Rendered Cine Computed Tomography of Isolated Left Ventricular Apical Hypoplasia: A Case Report and Literature Review.

    PubMed

    Hong, Sun Hwa; Kim, Yang Min; Lee, Hyun Jong

    2016-01-01

    We report multidetector computed tomography (MDCT) and cardiac magnetic resonance (CMR) findings of a 34-year-old female with isolated left ventricular apical hypoplasia. The MDCT and CMR scans displayed a spherical left ventricle (LV) with extensive fatty infiltration within the myocardium at the apex, interventricular septum and inferior wall, anteroapical origin of the papillary muscle, right ventricle wrapping around the deficient LV apex, and impaired systolic function. MDCT visualized morphologic and also functional findings of this unique cardiomyopathy. PMID:26798219

  1. Myocardial hypoperfusion on conventional contrast computed tomography.

    PubMed

    Ching, Shing; Chung, Tak Shun

    2015-10-01

    Non–electrocardiogram (ECG)–gated contrast computed tomography (CT) is commonly performed to exclude aortic dissection in chest pain patients. Besides evaluating the aorta for dissection flap, attention should be paid to the myocardium for areas of hypoenhancement that may suggest ischemia. Current models of multidetector CT enable assessment of myocardial perfusion with minimal motion artifact even without ECG gating. Transmural hypoenhancement with preserved wall thickness in a coronary distribution is highly specific for acute myocardial infarction. We report 2 cases of acute chest pain with initial nondiagnostic studies that underwent CT aortogram to exclude dissection. Instead, the CT showed myocardial hypoenhancement in left anterior descending artery territory. Myocardial hypoenhancement occurred before ST-segment elevation on ECG, suggesting that recognition of this important finding may lead to earlier revascularization decisions. PMID:26321167

  2. Volume Changes of Experimental Carotid Sidewall Aneurysms Due to Embolization with Liquid Embolic Agents: A Multidetector CT Angiography Study

    SciTech Connect

    Dudeck, O. Okuducu, A. F.; Jordan, O.; Tesmer, K.; Pech, M.; Weigang, E.; Ruefenacht, D. A.; Doelker, E.; Felix, R.

    2006-12-15

    Iodine-containing polyvinyl alcohol polymer (I-PVAL) is a novel precipitating liquid embolic that allows for artifact-free evaluation of CT angiography (CTA). As accurate aneurysm volumetry can be performed with multidetector CTA, we determined volumes of experimental aneurysms before, immediately after, and 4 weeks after embolization of 14 porcine experimental carotid sidewall aneurysms with this liquid embolic. An automated three-dimensional software measurement tool was used for volumetric analysis of volume-rendering CTA data. Furthermore, intra-aneurysmal pressure changes during liquid embolization were measured in four silicone aneurysms and potential polymer volume changes within 4 weeks were assessed in vitro. Liquid embolic injection was performed during temporary balloon occlusion of the aneurysm neck, resulting in a mean occlusion rate of 98.3%. Aneurysms enlarged significantly during embolization by 61.1 {+-} 28.9%, whereas a significant shrinkage of 5.6 {+-} 2.7% was observed within the follow-up period. Histologic analysis revealed an inflammatory foreign body reaction with partial polymer degradation. In silicone aneurysm models, intra-aneurysmal pressure remained unchanged during liquid embolic injection, whereas balloon inflation resulted in a mean pressure increase of 31.2 {+-} 0.7%. No polymer shrinkage was observed in vitro. The aneurysm enlargement noted was presumably due to pressure elevation after balloon inflation, which resulted in dilatation of the weak venous wall of the newly constructed aneurysm-another shortcoming of this experimental aneurysm model. The volume decrease after 4 weeks expressed partial polymer degradation.

  3. Multidetector CT Enterography versus Double-Balloon Enteroscopy: Comparison of the Diagnostic Value for Patients with Suspected Small Bowel Diseases

    PubMed Central

    Guo, Qiaozhen; Zhao, Jianping; Liu, Mei; Liao, Guangquan; Chen, Nianjun; Tian, Dean; Wu, Xiaoli

    2016-01-01

    Aim. To compare the diagnostic value of multidetector CT enterography (MDCTE) and double-balloon enteroscopy (DBE) for patients with suspected small bowel diseases. Methods. From January 2009 to January 2014, 190 patients with suspected small bowel diseases were examined with MDCTE and DBE. The characteristics of the patients, detection rates, diagnostic yields, sensitivity, specificity, positive predictive value, and negative predictive value were described and analyzed. Results. The overall detection rates of DBE and MDCTE were 92.6% and 55.8%, respectively (P<0.05), while the overall diagnostic yields were 83.2% and 33.7%, respectively (P<0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of DBE were all higher than those of MDCTE. DBE had a higher diagnostic yield for OGIB (87.3% versus 20.9%, P<0.05). The diagnostic yields of DBE were higher than those of MDCTE for inflammatory diseases, angioma/angiodysplasia, and diverticulums, while being not for gastrointestinal tumors/polyps. Conclusions. The diagnostic value of DBE for small bowel diseases is better than that of MDCTE as a whole, but if gastrointestinal tumors are suspected, MDCTE is also needed to gain a comprehensive and accurate diagnosis. PMID:26962305

  4. Multidetector CT Enterography versus Double-Balloon Enteroscopy: Comparison of the Diagnostic Value for Patients with Suspected Small Bowel Diseases.

    PubMed

    Wang, Jingjing; Guo, Qiaozhen; Zhao, Jianping; Liu, Mei; Liao, Guangquan; Chen, Nianjun; Tian, Dean; Wu, Xiaoli

    2016-01-01

    Aim. To compare the diagnostic value of multidetector CT enterography (MDCTE) and double-balloon enteroscopy (DBE) for patients with suspected small bowel diseases. Methods. From January 2009 to January 2014, 190 patients with suspected small bowel diseases were examined with MDCTE and DBE. The characteristics of the patients, detection rates, diagnostic yields, sensitivity, specificity, positive predictive value, and negative predictive value were described and analyzed. Results. The overall detection rates of DBE and MDCTE were 92.6% and 55.8%, respectively (P<0.05), while the overall diagnostic yields were 83.2% and 33.7%, respectively (P<0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of DBE were all higher than those of MDCTE. DBE had a higher diagnostic yield for OGIB (87.3% versus 20.9%, P<0.05). The diagnostic yields of DBE were higher than those of MDCTE for inflammatory diseases, angioma/angiodysplasia, and diverticulums, while being not for gastrointestinal tumors/polyps. Conclusions. The diagnostic value of DBE for small bowel diseases is better than that of MDCTE as a whole, but if gastrointestinal tumors are suspected, MDCTE is also needed to gain a comprehensive and accurate diagnosis. PMID:26962305

  5. [Computed tomography and cranial paleoanthropology].

    PubMed

    Cabanis, Emmanuel Alain; Badawi-Fayad, Jackie; Iba-Zizen, Marie-Thérèse; Istoc, Adrian; de Lumley, Henry; de Lumley, Marie-Antoinette; Coppens, Yves

    2007-06-01

    Since its invention in 1972, computed tomography (C.T.) has significantly evolved. With the advent of multi-slice detectors (500 times more sensitive than conventional radiography) and high-powered computer programs, medical applications have also improved. CT is now contributing to paleoanthropological research. Its non-destructive nature is the biggest advantage for studying fossil skulls. The second advantage is the possibility of image analysis, storage, and transmission. Potential disadvantages include the possible loss of files and the need to keep up with rapid technological advances. Our experience since the late 1970s, and a recent PhD thesis, led us to describe routine applications of this method. The main contributions of CT to cranial paleoanthropology are five-fold: --Numerical anatomy with rapid acquisition and high spatial resolution (helicoidal and multidetector CT) offering digital storage and stereolithography (3D printing). --Numerical biometry (2D and 3D) can be used to create "normograms" such as the 3D craniofacial reference model used in maxillofacial surgery. --Numerical analysis offers thorough characterization of the specimen and its state of conservation and/or restoration. --From "surrealism" to virtual imaging, anatomical structures can be reconstructed, providing access to hidden or dangerous zones. --The time dimension (4D imaging) confers movement and the possibility for endoscopic simulation and internal navigation (see Iconography). New technical developments will focus on data processing and networking. It remains our duty to deal respectfully with human fossils. PMID:18402165

  6. Pulmonary capillary hemangiomatosis: a focus on the EIF2AK4 mutation in onset and pathogenesis

    PubMed Central

    Ma, Lijiang; Bao, Ruijun

    2015-01-01

    Pulmonary capillary hemangiomatosis (PCH) is a pulmonary vascular disease that mainly affects small capillaries in the lung, and is often misdiagnosed as pulmonary arterial hypertension or pulmonary veno-occlusive disease due to similarities in their clinical presentations, prognosis, and management. In patients who are symptomatic, there is a high mortality rate with median survival of 3 years after diagnosis. Both idiopathic and familial PCH cases are being reported, indicating there is genetic component in disease etiology. Mutations in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene were identified in familial and idiopathic PCH cases, suggesting EIF2AK4 is a genetic risk factor for PCH. EIF2AK4 mutations were identified in 100% (6/6) of autosomal recessively inherited familial PCH and 20% (2/10) of sporadic PCH cases. EIF2AK4 is a member of serine/threonine kinases. It downregulates protein synthesis in response to a variety of cellular stress such as hypoxia, viral infection, and amino acid deprivation. Bone morphogenetic protein receptor 2 (BMPR2) is a major genetic risk factor in pulmonary arterial hypertension and EIF2AK4 potentially connects with BMPR2 to cause PCH. L-Arginine is substrate of nitric oxide synthase, and L-arginine is depleted during the production of nitric oxide, which may activate EIF2AK4 to inhibit protein synthesis and negatively regulate vasculogenesis. Mammalian target of rapamycin and EIF2α kinase are two major pathways for translational regulation. Mutant EIF2AK4 could promote proliferation of small pulmonary arteries by crosstalk with mammalian targets of the rapamycin signaling pathway. EIF2AK4 may regulate angiogenesis by modulating the immune system in PCH pathogenesis. The mechanisms of abnormal capillary angiogenesis are suggested to be similar to that of tumor vascularization. Specific therapies were developed according to pathogenesis and are proved to be effective in reported cases. Targeting the

  7. A compact ECL system for fast data readout and event building in a multidetector environment

    NASA Astrophysics Data System (ADS)

    Finocchiaro, Paolo; Calì, Claudio

    1992-11-01

    A totally hardware readout system is described. It was conceived in order to coordinate a number of parallel chains of FERA_bus converters, and to output the event data in a general formal suitable for being directly handled by data acquisition computers.

  8. M. tuberculosis ferritin (Rv3841): Potential involvement in Amikacin (AK) & Kanamycin (KM) resistance.

    PubMed

    Sharma, Divakar; Lata, Manju; Faheem, Mohammad; Khan, Asad Ullah; Joshi, Beenu; Venkatesan, Krishnamurthy; Shukla, Sangeeta; Bisht, Deepa

    2016-09-16

    Tuberculosis is an infectious disease, caused by one of the most successful human pathogen, Mycobacterium tuberculosis. Aminoglycosides, Amikacin (AK) & Kanamycin (KM) are commonly used to treat drug resistant tuberculosis. They target the protein synthesis machinery by interacting with several steps of translation. Several explanations have been proposed to explain the mechanism of aminoglycoside resistance but still our information is inadequate. Iron storing/interacting proteins were found to be overexpressed in aminoglycosides resistant isolates. Iron assimilation and utilization in M. tuberculosis plays a crucial role in growth, virulence and latency. To establish the relationship of ferritin with AK & KM resistance ferritin (Rv3841/bfrB) was cloned, expressed and antimicrobial drug susceptibility testing (DST) was carried out. Rv3841/bfrB gene was cloned and expressed in E. coli BL21 using pQE2 expression vector. Etest results for DST against AK & KM showed that the minimum inhibitory concentration (MIC) of ferritin recombinant cells was changed. Recombinants showed two fold changes in MIC with AK and three fold with KM E-strips. Overexpression of ferritin reflect the MIC shift which might be playing a critical role in the survival of mycobacteria by inhibiting/modulating the effects of AK & KM. String analysis also suggests that ferritin interacted with few proteins which are directly and indirectly involved in M. tuberculosis growth, Iron assimilation, virulence, resistance, stresses and latency. PMID:27521892

  9. Lmax and imiquimod 3.75%: the new standard in AK management.

    PubMed

    Stockfleth, E

    2015-01-01

    The new target for the treatment of actinic keratosis (AK) is the detection and clearance of clinical and subclinical lesions across an entire sun-exposed field. This is because patients with AK have field cancerization as ultraviolet light affects the entire sun-exposed area and because it is not possible to predict which AK lesions will progress into invasive squamous cell carcinoma. To fully assess the effectiveness of field-directed therapies against the full burden of AK, a new efficacy concept has been developed which is based on the reduction in lesions from Lmax, or the maximum lesion count during treatment. This new parameter enables the efficacy of a field-directed therapy against both clinical and subclinical lesions to be assessed. Imiquimod 3.75% is a novel field-directed therapy which uniquely can detect and clear both clinical and subclinical lesions across a large sun-exposed field such as the full face or balding scalp, and so far is the only AK treatment to have had its efficacy assessed with the Lmax concept. The detection of subclinical lesions is evidenced by an increase in lesion count during each of the 2-week treatment cycles, which are separated by a 2-week treatment-free interval. The median percentage reduction in lesions from Lmax with imiquimod 3.75% is 92%, and the effective clearance of both clinical and subclinical lesions leads to sustained lesion clearance for at least 1 year. Imiquimod 3.75% has an acceptable tolerability profile. Rest periods from treatment may be taken if required to manage local skin reactions, with no loss in efficacy. In conclusion, Lmax and imiquimod 3.75% together set the new standard in the management of patients with AK. PMID:25470719

  10. Multi-detector CT assessment in pulmonary hypertension: techniques, systematic approach to interpretation and key findings

    PubMed Central

    Lewis, Gareth; Reynolds, John H.; Ganeshan, Arul; Ment, Jerome

    2015-01-01

    Pulmonary arterial hypertension (PAH) may be suspected based on the clinical history, physical examination and electrocardiogram findings but imaging is usually central to confirming the diagnosis, establishing a cause and guiding therapy. The diagnostic pathway of PAH involves a variety of complimentary investigations of which computed tomography pulmonary angiography (CTPA) has established a central role both in helping identify an underlying cause for PAH and assessing resulting functional compromise. In particular CTPA is considered as the gold standard technique for the diagnosis of thromboembolic disease. This article reviews the CTPA evaluation in PAH, describing CTPA techniques, a systematic approach to interpretation and spectrum of key imaging findings. PMID:26029645

  11. Crossed Fused Renal Ectopia: Presentations on 99mTc-MAG3 Scan, 99mTc-DMSA SPECT, and Multidetector CT.

    PubMed

    Moon, Eun Ha; Kim, Min-Woo; Kim, Young Jun; Sun, In O

    2015-10-01

    Crossed renal ectopia is an uncommon developmental anomaly in which both kidneys are located on the same side of the body. The present case describes a 20-year-old man who underwent the military entrance physical examination. The ultrasound showed the right kidney in normal site with slightly increased size, but the left kidney was not identified. Tc-MAG3 scan showed a single kidney with 2 ureters, and the orifices of the ureters were connected at both sides of bladder. Tc-DMSA SPECT and contrast-enhanced multidetector CT were performed and revealed crossed fused renal ectopia. PMID:26252333

  12. Development of a parallel detection and processing system using a multidetector array for wave field restoration in scanning transmission electron microscopy

    SciTech Connect

    Taya, Masaki; Matsutani, Takaomi; Ikuta, Takashi; Saito, Hidekazu; Ogai, Keiko; Harada, Yoshihito; Tanaka, Takeo; Takai, Yoshizo

    2007-08-15

    A parallel image detection and image processing system for scanning transmission electron microscopy was developed using a multidetector array consisting of a multianode photomultiplier tube arranged in an 8x8 square array. The system enables the taking of 64 images simultaneously from different scattered directions with a scanning time of 2.6 s. Using the 64 images, phase and amplitude contrast images of gold particles on an amorphous carbon thin film could be separately reconstructed by applying respective 8 shaped bandpass Fourier filters for each image and multiplying the phase and amplitude reconstructing factors.

  13. Development of a parallel detection and processing system using a multidetector array for wave field restoration in scanning transmission electron microscopy.

    PubMed

    Taya, Masaki; Matsutani, Takaomi; Ikuta, Takashi; Saito, Hidekazu; Ogai, Keiko; Harada, Yoshihito; Tanaka, Takeo; Takai, Yoshizo

    2007-08-01

    A parallel image detection and image processing system for scanning transmission electron microscopy was developed using a multidetector array consisting of a multianode photomultiplier tube arranged in an 8 x 8 square array. The system enables the taking of 64 images simultaneously from different scattered directions with a scanning time of 2.6 s. Using the 64 images, phase and amplitude contrast images of gold particles on an amorphous carbon thin film could be separately reconstructed by applying respective 8 shaped bandpass Fourier filters for each image and multiplying the phase and amplitude reconstructing factors. PMID:17764327

  14. Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT

    PubMed Central

    Dobeli, K L; Lewis, S J; Meikle, S R; Thiele, D L; Brennan, P C

    2013-01-01

    Objective: To compare the dose-optimisation potential of a smoothing filtered backprojection (FBP) and a hybrid FBP/iterative algorithm to that of a standard FBP algorithm at three slice thicknesses for hepatic lesion detection with multidetector CT. Methods: A liver phantom containing a 9.5-mm opacity with a density of 10 HU below background was scanned at 125, 100, 75, 50 and 25 mAs. Data were reconstructed with standard FBP (B), smoothing FBP (A) and hybrid FBP/iterative (iDose4) algorithms at 5-, 3- and 1-mm collimation. 10 observers marked opacities using a four-point confidence scale. Jackknife alternative free-response receiver operating characteristic figure of merit (FOM), sensitivity and noise were calculated. Results: Compared with the 125-mAs/5-mm setting for each algorithm, significant reductions in FOM (p<0.05) and sensitivity (p<0.05) were found for all three algorithms for all exposures at 1-mm thickness and for all slice thicknesses at 25 mAs, with the exception of the 25-mAs/5-mm setting for the B algorithm. Sensitivity was also significantly reduced for all exposures at 3-mm thickness for the A algorithm (p<0.05). Noise for the A and iDose4 algorithms was approximately 13% and 21% lower, respectively, than for the B algorithm. Conclusion: Superior performance for hepatic lesion detection was not shown with either a smoothing FBP algorithm or a hybrid FBP/iterative algorithm compared with a standard FBP technique, even though noise reduction with thinner slices was demonstrated with the alternative approaches. Advances in knowledge: Reductions in image noise with non-standard CT algorithms do not necessarily translate to an improvement in low-contrast object detection. PMID:23392194

  15. Clinical value of multidetector CT coronary angiography as a preoperative screening test before non‐coronary cardiac surgery

    PubMed Central

    Russo, Vincenzo; Gostoli, Valentina; Lovato, Luigi; Montalti, Maurizio; Marzocchi, Antonio; Gavelli, Giampaolo; Branzi, Angelo; Bartolomeo, Roberto Di; Fattori, Rossella

    2007-01-01

    Objective Myocardial scintigraphy and/or conventional angiography (CA) are often performed before cardiac surgery in an attempt to identify unsuspected coronary artery disease which might result in significant cardiac morbidity and mortality. Multidetector CT coronary angiography (MDCTCA) has a recognised high negative predictive value and may provide a non‐invasive alternative in this subset of patients. The aim of this study was to evaluate the clinical value of MDCTCA as a preoperative screening test in candidates for non‐coronary cardiac surgery. Methods 132 patients underwent MDCTCA (Somatom Sensation 16 Cardiac, Siemens) in the assessment of the cardiac risk profile before surgery. Coronary arteries were screened for ⩾50% stenosis. Patients without significant stenosis (Group 1) underwent surgery without any adjunctive screening tests while all patients with coronary lesions ⩾50% at MDCTCA (Group 2) underwent CA. Results 16 patients (12.1%) were excluded due to poor image quality. 72 patients without significant coronary stenosis at MDCTCA were submitted to surgery. 30 out of 36 patients with significant (⩾50%) coronary stenosis at MDCTCA and CA underwent adjunctive bypass surgery or coronary angioplasty. In 8 patients, MDCTCA overestimated the severity of the coronary lesions (>50% MDCTCA, <50% CA). No severe cardiovascular perioperative events such as myocardial ischaemia, myocardial infarction or cardiac failure occurred in any patient in Group 1. Conclusions MDCTCA seems to be effective as a preoperative screening test prior to non‐coronary cardiac surgery. In this era of cost containment and optimal care of patients, MDCTCA is able to provide coronary vessel and ventricular function evaluation and may become the method of choice for the assessment of a cardiovascular risk profile prior to major surgery. PMID:17164488

  16. Radiological protection in computed tomography and cone beam computed tomography.

    PubMed

    Rehani, M M

    2015-06-01

    The International Commission on Radiological Protection (ICRP) has sustained interest in radiological protection in computed tomography (CT), and ICRP Publications 87 and 102 focused on the management of patient doses in CT and multi-detector CT (MDCT) respectively. ICRP forecasted and 'sounded the alarm' on increasing patient doses in CT, and recommended actions for manufacturers and users. One of the approaches was that safety is best achieved when it is built into the machine, rather than left as a matter of choice for users. In view of upcoming challenges posed by newer systems that use cone beam geometry for CT (CBCT), and their widened usage, often by untrained users, a new ICRP task group has been working on radiological protection issues in CBCT. Some of the issues identified by the task group are: lack of standardisation of dosimetry in CBCT; the false belief within the medical and dental community that CBCT is a 'light', low-dose CT whereas mobile CBCT units and newer applications, particularly C-arm CT in interventional procedures, involve higher doses; lack of training in radiological protection among clinical users; and lack of dose information and tracking in many applications. This paper provides a summary of approaches used in CT and MDCT, and preliminary information regarding work just published for radiological protection in CBCT. PMID:25816279

  17. 78 FR 76055 - Establishment of Class E Airspace; Donlin Creek, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-16

    ... rulemaking (NPRM) to establish controlled airspace at Donlin Creek, AK (78 FR 58490). Interested parties were...'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant... FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in 14 CFR...

  18. 75 FR 54661 - Alaska Disaster #AK-00018 Declaration of Economic Injury

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-08

    ... ADMINISTRATION Alaska Disaster AK-00018 Declaration of Economic Injury AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Economic Injury Disaster Loan (EIDL) declaration for the...., Suite 6050, Washington, DC 20416. SUPPLEMENTARY INFORMATION: Notice is hereby given that as a result...

  19. 77 FR 71667 - Alaska Disaster #AK-00026 Declaration of Economic Injury

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-03

    ... ADMINISTRATION Alaska Disaster AK-00026 Declaration of Economic Injury AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Economic Injury Disaster Loan (EIDL) declaration for the...., Suite 6050, Washington, DC 20416. SUPPLEMENTARY INFORMATION: Notice is hereby given that as a result...

  20. 75 FR 77572 - Proposed Revision of Class E Airspace; Platinum AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-13

    ...; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February.... 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 2. The... Federal Aviation Administration 14 CFR Part 71 Proposed Revision of Class E Airspace; Platinum AK...

  1. 75 FR 32652 - Revocation and Establishment of Class E Airspace; Nuiqsut, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ... privately owned heliport facilities at Oooguruk, AK (74 FR 45554). The two heliports were named ``Oooguruk... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of.... 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0...

  2. 77 FR 50646 - Proposed Establishment of Class D Airspace; Bryant AAF, Anchorage, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR....S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1...), Anchorage AK. Controlled airspace is necessary due to an increase in the complexity, volume and variety...

  3. 78 FR 48299 - Establishment of Class D Airspace; Bryant AAF, Anchorage, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ..., Anchorage AK (77 FR 50646). Interested parties were invited to participate in this rulemaking effort by... would eliminate that portion east of Glenn Highway (FR 78 34608, June 10, 2013). Interested parties were... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...

  4. 77 FR 39172 - Safety Zone: Skagway Harbor, Skagway, AK for 4th of July Fireworks

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone: Skagway Harbor, Skagway, AK for 4th of July... 4th of July Fireworks display. Persons desiring to transit within this safety zone must contact the... Inlet for the City of Skagway, Alaska, sponsored 4th of July fireworks display. A no-action...

  5. 75 FR 62460 - Revocation and Establishment of Class E Airspace; Northeast Alaska, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... establish other Class E airspace near the Eagle Airport, Eagle, AK (75 FR 30746). The proposal did not fully... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec....

  6. 78 FR 19431 - Safety Zones; Annual Independence Day Fireworks Displays, Skagway, Haines, and Wrangell, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-01

    ... FR Federal Register NPRM Notice of Proposed Rulemaking A. Public Participation and Request for... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). 4. Public Meeting We... waters in the vicinity of Haines, Skagway and Wrangell, AK (77 FR 39172). This rule proposes to...

  7. 76 FR 56354 - Proposed Amendment of Class E Airspace; Anaktuvuk Pass, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-13

    ... Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a... read as follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959...: This action proposes to revise Class E airspace at Anaktuvuk Pass, AK. The creation of two...

  8. 76 FR 49388 - Proposed Establishment of Class E Airspace; Tatitlek, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-10

    ... 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 2. The incorporation by...: This action proposes to establish Class E airspace at Tatitlek, AK. The creation of a...

  9. 77 FR 6 - Amendment of Class E Airspace; Galbraith Lake, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ... amend controlled airspace at Galbraith Lake, AK (76 FR 54152). Interested parties were invited to... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR...), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2....

  10. The Library Haines Built: Best Small Library in America 2005--Haines Borough Public Library, Haines, AK

    ERIC Educational Resources Information Center

    Berry, John N., III

    2005-01-01

    "Community involvement," the standard cliche, does not come close to capturing the spirit and action that have structured the building, programs, collections, and services of the Haines Borough Public Library (HBPL), AK. Those achievements make HBPL the winner of the first annual award for the Best Small Library in America, cosponsored by Library…

  11. 75 FR 62457 - Establishment of Class E Airspace; Port Clarence, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... Federal Register to establish Class E airspace at Port Clarence, AK (75 FR 34393). Interested parties were... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does... U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec....

  12. 75 FR 81110 - Establishment of Class E Airspace; Port Clarence, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ..., Tuesday, October 12, 2010 (75 FR 62457), FR Doc 2010-25479, page 62458, column 2 is corrected as follows... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Port Clarence, AK AGENCY... errors in the legal description and airport coordinates for Port Clarence Coast Guard Station...

  13. 75 FR 17322 - Proposed Revocation of Class D and E Airspace; Big Delta, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ...This action proposes to revoke Class D and E airspace at Big Delta, AK. This airspace duplicates the controlled airspace for Delta Junction, Alaska, which serves Allen Army Airfield. The duplication makes this action necessary to eliminate possible confusion, and enhance safety and management of Instrument Flight Rules (IFR)...

  14. 78 FR 65239 - Proposed Establishment of Class E Airspace; Brevig Mission, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ...This action proposes to establish Class E airspace at Brevig Mission Airport, Brevig Mission, AK. Controlled airspace is necessary to accommodate aircraft using new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at the airport. The FAA is proposing this action to enhance the safety and management of aircraft operations at the...

  15. 78 FR 65237 - Proposed Establishment of Class E Airspace; Central, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ...This action proposes to establish Class E airspace at Central Airport, Central, AK. Controlled airspace is necessary to accommodate the new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at the airport. The FAA is proposing this action to enhance the safety and management of aircraft operations at Central Airport, Central,...

  16. 78 FR 65238 - Proposed Establishment of Class E Airspace; Eagle, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ...This action proposes to establish Class E airspace at Eagle Airport, Eagle, AK. Controlled airspace is necessary to accommodate the new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures developed for the airport. The FAA is proposing this action to enhance the safety and management of aircraft operations at Eagle Airport, Eagle,...

  17. 75 FR 17892 - Proposed Revision of Class E Airspace; Galena, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-08

    ... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of... follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp... Federal Aviation Administration 14 CFR Part 71 Proposed Revision of Class E Airspace; Galena, AK...

  18. 77 FR 65253 - Amendment of Area Navigation Route T-240; AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation... Administration 14 CFR Part 71 RIN 2120-AA66 Amendment of Area Navigation Route T-240; AK AGENCY: Federal...

  19. 78 FR 50322 - Amendment of Class E Airspace; Point Thomson, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... controlled airspace at Point Thomson, AK (78 FR 30797). Interested parties were invited to participate in... a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979..., 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The...

  20. 78 FR 17083 - Amendment of Class E Airspace; Scammon Bay, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... Bay, AK (77 FR 27146). Interested parties were invited to participate in this rulemaking effort by... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of... FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in 14 CFR...

  1. 77 FR 49720 - Establishment of Class E Airspace; Chenega Bay, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-17

    ... proposed rulemaking (NPRM) to establish controlled airspace at Chenega Bay, AK (77 FR 31548). Interested... Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a...: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p....

  2. 78 FR 65208 - Modification of Class D and E Airspace; Kenai, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ...This action modifies Class D and E airspace at Kenai Municipal Airport, Kenai, AK. Controlled airspace is necessary to accommodate aircraft using the new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at the airport. A minor adjustment is made to the geographic coordinates of the airport. Additionally, language establishing dates and times of use......

  3. 77 FR 31353 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... AGENCY An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, AK AGENCY... of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska'' (EPA-910-R-12-004a-d). The... significance of Bristol Bay's ecological resources and evaluate the potential impacts of large-scale mining...

  4. 77 FR 23269 - Determination That FUNDUSCEIN-25 (fluorescein sodium injection), 25%, and AK-FLUOR (fluorescein...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... HUMAN SERVICES Food and Drug Administration Determination That FUNDUSCEIN-25 (fluorescein sodium injection), 25%, and AK-FLUOR (fluorescein sodium injection), 25%, Were Not Withdrawn From Sale for Reasons... Food and Drug Administration (FDA) has determined that FUNDUSCEIN-25 (fluorescein sodium injection),...

  5. 78 FR 58158 - Establishment of Class D Airspace; Bryant AAF, Anchorage, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... Register establishing Class D airspace at Bryant AAF, Anchorage, AK (78 FR 48299, August 8, 2013). In the..., as published in the Federal Register on August 8, 2013 (78 FR 48299), FR Doc. 2013-18866, are... Federal Aviation Administration 14 CFR Part 71 Establishment of Class D Airspace; Bryant AAF,...

  6. 78 FR 59806 - Establishment of Class E Airspace; White Mountain, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-30

    ... Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at the airport..., Airport, White Mountain, AK (77 FR 75598). Interested parties were invited to participate in this... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...

  7. A retrospective comparison of smart prep and test bolus multi-detector CT pulmonary angiography protocols

    SciTech Connect

    Suckling, Tara; Smith, Tony; Reed, Warren

    2013-06-15

    Optimal arterial opacification is crucial in imaging the pulmonary arteries using computed tomography (CT). This poses the challenge of precisely timing data acquisition to coincide with the transit of the contrast bolus through the pulmonary vasculature. The aim of this quality assurance exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk. A total of 160 CTPA examinations (80 using each protocol) performed between January 2010 and February 2011 were assessed retrospectively. CT attenuation coefficients were measured in Hounsfield Units (HU) using regions of interest at the level of the pulmonary trunk. The average pixel value, standard deviation (SD), maximum, and minimum were recorded. For each of these variables a mean value was then calculated and compared for these two CTPA protocols. Minimum opacification of 200 HU was achieved in 98% of the TBP sample but only 90% of the SPP sample. The average CT attenuation over the pulmonary trunk for the SPP was 329 (SD = ±21) HU, whereas for the TBP it was 396 (SD = ±22) HU (P = 0.0017). The TBP also recorded higher maximum (P = 0.0024) and minimum (P = 0.0039) levels of opacification. This study has found that a TBP resulted in significantly better opacification of the pulmonary trunk than the SPP.

  8. Calpain inhibitor AK295 attenuates motor and cognitive deficits following experimental brain injury in the rat.

    PubMed Central

    Saatman, K E; Murai, H; Bartus, R T; Smith, D H; Hayward, N J; Perri, B R; McIntosh, T K

    1996-01-01

    Marked increases in intracellular calcium may play a role in mediating cellular dysfunction and death following central nervous system trauma, in part through the activation of the calcium-dependent neutral protease calpain. In this study, we evaluated the effect of the calpain inhibitor AK295 [Z-Leu-aminobutyric acid-CONH(CH2)3-morpholine] on cognitive and motor deficits following lateral fluid percussion brain injury in rats. Before injury, male Sprague-Dawley rats (350-425 g) were trained to perform a beam-walking task and to learn a cognitive test using a Morris water maze paradigm. Animals were subjected to fluid percussion injury (2.2-2.4 atm; 1 atm = 101.3 kPa) and, beginning at 15 min postinjury, received a continuous intraarterial infusion of AK295 (120-140 mg/kg, n = 15) or vehicle (n= 16) for 48 hr. Sham (uninjured) animals received either drug (n = 5) or vehicle (n = 10). Animals were evaluated for neurobehavioral motor function at 48 hr and 7 days postinjury and were tested in the Morris water maze to evaluate memory retention at 7 days postinjury. At 48 hr, both vehicle- and AK295-treated injured animals showed significant neuromotor deficits (P< 0.005). At 7 days, injured animals that received vehicle continued to exhibit significant motor dysfunction (P< 0.01). However, brain-injured, AK295-treated animals showed markedly improved motor scores (P<0.02), which were not significantly different from sham (uninjured) animals. Vehicle-treated, injured animals demonstrated a profound cognitive deficit (P< 0.001), which was significantly attenuated by AK295 treatment (P< 0.05). To our knowledge, this study is the first to use a calpain inhibitor following brain trauma and suggests that calpain plays a role in the posttraumatic events underlying memory and neuromotor dysfunction. PMID:8622952

  9. Kinetics of nutrient enhanced crude oil degradation by Pseudomonas aeruginosa AKS1 and Bacillus sp. AKS2 isolated from Guwahati refinery, India.

    PubMed

    Chettri, Bobby; Mukherjee, Arghya; Langpoklakpam, James S; Chattopadhyay, Dhrubajyoti; Singh, Arvind K

    2016-09-01

    Bacterial degradation of crude oil in response to nutrient treatments has been vastly studied. But there is a paucity of information on kinetic parameters of crude oil degradation. Here we report the nutrient stimulated kinetic parameters of crude oil degradation assessed in terms of CO2 production and oil removal by Pseudomonas aeruginosa AKS1 and Bacillus sp. AKS2. The hydrocarbon degradation rate of P. aeruginosa AKS1 in oil only amended sediment was 10.75 ± 0.65 μg CO2-C g(-1) sediment day(-1) which was similar to degradation rate in sediments with no oil. In presence of both inorganic N & P, the degradation rate increased to 47.22 ± 1.32 μg CO2-C g(-1) sediment day(-1). The half-saturation constant (Ks) and maximum degradation rate (Vmax) for P. aeruginosa AKS1 under increasing N and saturating P concentration were 13.57 ± 0.53 μg N g(-1) sediment and 39.36 ± 1.42 μg CO2-C g(-1) sediment day(-1) respectively. The corresponding values at increasing P and a constant N concentration were 1.60 ± 0.13 μg P g(-1) sediment and 43.90 ± 1.03 μg CO2-C g(-1) sediment day(-1) respectively. Similarly the degradation rate of Bacillus sp. AKS2 in sediments amended with both inorganic nutrients N & P was seven fold higher than the rates in oil only or nutrient only treated sediments. The Ks and Vmax estimates of Bacillus sp. AKS2 under increasing N and saturating P concentration were 9.96 ± 1.25 μg N g(-1) sediment and 59.96 ± 7.56 μg CO2-C g(-1) sediment day(-1) respectively. The corresponding values for P at saturating N concentration were 0.46 ± 0.24 μg P g(-1) sediment and 63.63 ± 3.54 μg CO2-C g(-1) sediment day(-1) respectively. The rates of CO2 production by both isolates were further stimulated when oil concentration was increased above 12.5 mg g(-1) sediment. However, oil degradation activity declined at oil concentration above 40 mg g(-1) sediment when treated with constant nutrient: oil ratio

  10. Reliability of vertebral fracture assessment using multidetector CT lateral scout views: the Framingham Osteoporosis Study

    PubMed Central

    Samelson, E. J.; Christiansen, B. A.; Demissie, S.; Broe, K. E.; Zhou, Y.; Meng, C. A.; Yu, W.; Cheng, X.; O’Donnell, C. J.; Hoffmann, U.; Genant, H. K.; Kiel, D. P.; Bouxsein, M. L.

    2010-01-01

    Summary Two radiologists evaluated images of the spine from computed tomography (CT) scans on two occasions to diagnose vertebral fracture in 100 individuals. Agreement was fair to good for mild fractures, and agreement was good to excellent for more severe fractures. CT scout views are useful to assess vertebral fracture. Introduction We investigated inter-reader agreement between two radiologists and intra-reader agreement between duplicate readings for each radiologist, in assessment of vertebral fracture using a semi-quantitative method from lateral scout views obtained by CT. Methods Participants included 50 women and 50 men (age 50-87 years, mean 70 years) in the Framingham Study. T4-L4 vertebrae were assessed independently by two radiologists on two occasions using a semi-quantitative scale as normal, mild, moderate, or severe fracture. Results Vertebra-specific prevalence of grade ≥1 (mild) fracture ranged from 3% to 5%. We found fair (κ=56-59%) inter-reader agreement for grade ≥1 vertebral fractures and good (κ=68-72%) inter-reader agreement for grade ≥2 fractures. Intra-reader agreement for grade ≥1 vertebral fracture was fair (κ=55%) for one reader and excellent for another reader (κ=77%), whereas intra-reader agreement for grade ≥2 vertebral fracture was excellent for both readers (κ=76% and 98%). Thoracic vertebrae were more difficult to evaluate than the lumbar region, and agreement was lowest (inter-reader κ=43%) for fracture at the upper (T4-T9) thoracic levels and highest (inter-reader κ=76-78%) for the lumbar spine (L1-L4). Conclusions Based on a semi-quantitative method to classify vertebral fractures using CT scout views, agreement within and between readers was fair to good, with the greatest source of variation occurring for fractures of mild severity and for the upper thoracic region. Agreement was good to excellent for fractures of at least moderate severity. Lateral CT scout views can be useful in clinical research settings

  11. Feature-based characterization of motion-contaminated calcified plaques in cardiac multidetector CT

    SciTech Connect

    King, Martin; Giger, Maryellen L.; Suzuki, Kenji; Pan, Xiaochuan

    2007-12-15

    features mostly involved intensity-based features. Edge-based volume/irregularity and average margin gradient/variance of margin gradient were the only two feature pairs out of 12 with stronger correlations that did not involve intensity-based features. Automatically extracted features of the motion artifacts affecting calcified plaques in cardiac computed tomography images potentially can be used to develop models for predicting image assessability with respect to motion artifacts.

  12. Monte Carlo simulations to assess the effects of tube current modulation on breast dose for multidetector CT

    PubMed Central

    Angel, Erin; Yaghmai, Nazanin; Jude, Cecilia Matilda; DeMarco, John J; Cagnon, Christopher H; Goldin, Jonathan G; Primak, Andrew N; Stevens, Donna M; Cody, Dianna D; McCollough, Cynthia H; McNitt-Gray, Michael F

    2010-01-01

    Tube current modulation was designed to reduce radiation dose in CT imaging while maintaining overall image quality. This study aims to develop a method for evaluating the effects of tube current modulation (TCM) on organ dose in CT exams of actual patient anatomy. This method was validated by simulating a TCM and a fixed tube current chest CT exam on 30 voxelized patient models and estimating the radiation dose to each patient’s glandular breast tissue. This new method for estimating organ dose was compared with other conventional estimates of dose reduction. Thirty detailed voxelized models of patient anatomy were created based on image data from female patients who had previously undergone clinically indicated CT scans including the chest area. As an indicator of patient size, the perimeter of the patient was measured on the image containing at least one nipple using a semi-automated technique. The breasts were contoured on each image set by a radiologist and glandular tissue was semi-automatically segmented from this region. Previously validated Monte Carlo models of two multidetector CT scanners were used, taking into account details about the source spectra, filtration, collimation and geometry of the scanner. TCM data were obtained from each patient’s clinical scan and factored into the model to simulate the effects of TCM. For each patient model, two exams were simulated: a fixed tube current chest CT and a tube current modulated chest CT. X-ray photons were transported through the anatomy of the voxelized patient models, and radiation dose was tallied in the glandular breast tissue. The resulting doses from the tube current modulated simulations were compared to the results obtained from simulations performed using a fixed mA value. The average radiation dose to the glandular breast tissue from a fixed tube current scan across all patient models was 19 mGy. The average reduction in breast dose using the tube current modulated scan was 17%. Results were

  13. Results of the Test Program for Replacement of AK-225G Solvent for Cleaning NASA Propulsion Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.; Mitchell, Mark A.

    2016-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance chlorofluorocarbon-113 was banned, NASA's propulsion test facilities at Marshall Space Flight Center and Stennis Space Center have relied upon the solvent Asahiklin AK-225 (hydrochlorofluorocarbon-225ca/cb or HCFC-225ca/cb) and, more recently AK-225G (the single isomer form, HCFC-225cb) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of Class II Ozone Depleting Substances, including AK-225G, was prohibited in the United States by the Clean Air Act. In 2012 through 2014, NASA test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility collaborated to seek out, test, and qualify a solvent replacement for AK-225G that is both an effective cleaner and safe for use with oxygen systems. This paper summarizes the tests performed, results, and lessons learned.

  14. Computerized assessment of motion-contaminated calcified plaques in cardiac multidetector CT

    SciTech Connect

    King, Martin; Giger, Maryellen L.; Suzuki, Kenji; Bardo, Dianna M. E.; Greenberg, Brent; Lan Li; Pan Xiaochuan

    2007-12-15

    An automated method for evaluating the image quality of calcified plaques with respect to motion artifacts in noncontrast-enhanced cardiac computed tomography (CT) images is introduced. This method involves using linear regression (LR) and artificial neural network (ANN) regression models for predicting two patient-specific, region-of-interest-specific, reconstruction-specific and temporal phase-specific image quality indices. The first is a plaque motion index, which is derived from the actual trajectory of the calcified plaque and is represented on a continuous scale. The second is an assessability index, which reflects the degree to which a calcified plaque is affected by motion artifacts, and is represented on an ordinal five-point scale. Two sets of assessability indices were provided independently by two radiologists experienced in evaluating cardiac CT images. Inputs for the regression models were selected from 12 features characterizing the dynamic, morphological, and intensity-based properties of the calcified plaques. Whereas LR-velocity (LR-V) used only a single feature (three-dimensional velocity), the LR-multiple (LR-M) and ANN regression models used the same subset of these 12 features selected through stepwise regression. The regression models were parameterized and evaluated using a database of simulated calcified plaque images from the dynamic NCAT phantom involving nine heart rate/multi-sector gating combinations and 40 cardiac phases covering two cardiac cycles. Six calcified plaques were used for the plaque motion indices and three calcified plaques were used for both sets of assessability indices. In one configuration, images from the second cardiac cycle were used for feature selection and regression model parameterization, whereas images from the first cardiac cycle were used for testing. With this configuration, repeated measures concordance correlation coefficients (CCCs) and associated 95% confidence intervals for the LR-V, LR-M, and ANN

  15. 75 FR 12976 - Amendment of Restricted Area R-2204 High and R-2204 Low; Oliktok Point, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-18

    ...This action amends R-2204 High and R-2204 Low at Oliktok Point, AK, by increasing the authorized times of designation and extending the duration of the restricted areas beyond 2009, until they are no longer needed by the Department of Energy (DOE). Continued access to R-2204 High and R-2204 Low at Oliktok, AK, is required for current moored balloon and future climate-related aviation......

  16. Crystal structure of Clostridium acetobutylicum Aspartate kinase (CaAK): An important allosteric enzyme for amino acids production.

    PubMed

    Manjasetty, Babu A; Chance, Mark R; Burley, Stephen K; Panjikar, Santosh; Almo, Steven C

    2014-09-01

    Aspartate kinase (AK) is an enzyme which is tightly regulated through feedback control and responsible for the synthesis of 4-phospho-L-aspartate from L-aspartate. This intermediate step is at an important branch point where one path leads to the synthesis of lysine and the other to threonine, methionine and isoleucine. Concerted feedback inhibition of AK is mediated by threonine and lysine and varies between the species. The crystal structure of biotechnologically important Clostridium acetobutylicum aspartate kinase (CaAK; E.C. 2.7.2.4; Mw=48,030Da; 437aa; SwissProt: Q97MC0) has been determined to 3Å resolution. CaAK acquires a protein fold similar to the other known structures of AKs despite the low sequence identity (<30%). It is composed of two domains: an N-terminal catalytic domain (kinase) domain and a C-terminal regulatory domain further comprised of two small domains belonging to the ACT domain family. Pairwise comparison of 12 molecules in the asymmetric unit helped to identify the bending regions which are in the vicinity of ATP binding site involved in domain movements between the catalytic and regulatory domains. All 12 CaAK molecules adopt fully open T-state conformation leading to the formation of three tetramers unique among other similar AK structures. On the basis of comparative structural analysis, we discuss tetramer formation based on the large conformational changes in the catalytic domain associated with the lysine binding at the regulatory domains. The structure described herein is homologous to a target in wide-spread pathogenic (toxin producing) bacteria such as Clostridium tetani (64% sequence identity) suggesting the potential of the structure solved here to be applied for modeling drug interactions. CaAK structure may serve as a guide to better understand and engineer lysine biosynthesis for the biotechnology industry. PMID:25170437

  17. The U.S. M-16 rifle versus the Russian AK-47 rifle. A comparison of terminal ballistics.

    PubMed

    Swan, K G; Swan, R C; Levine, M G; Rocko, J M

    1983-09-01

    The standard U.S. military rifle (M-16) is substantially more destructive than its Russian counterpart (AK-47) when fired at short range into clay blocks, despite the fact that the AK-47 is of larger caliber and fires a much heavier bullet with a kinetic energy (muzzle) 25% greater when compared to the M-16. The decisive factor is the 40% greater muzzle velocity of the M-16. PMID:6625357

  18. Silencing the HaAK Gene by Transgenic Plant-Mediated RNAi Impairs Larval Growth of Helicoverpa armigera

    PubMed Central

    Liu, Feng; Wang, Xiao-Dong; Zhao, Yi-Ying; Li, Yan-Jun; Liu, Yong-Chang; Sun, Jie

    2015-01-01

    Insect pests have caused noticeable economic losses in agriculture, and the heavy use of insecticide to control pests not only brings the threats of insecticide resistance but also causes the great pollution to foods and the environment. Transgenic plants producing double-stranded RNA (dsRNA) directed against insect genes have been is currently developed for protection against insect pests. In this study, we used this technology to silence the arginine kinase (AK) gene of Helicoverpa armigera (HaAK), encoding a phosphotransferase that plays a critical role in cellular energy metabolism in invertebrate. Transgenic Arabidopsis plants producing HaAK dsRNA were generated by Agrobacterium-mediated transformation. The maximal mortality rate of 55% was reached when H. armigera first-instar larvae were fed with transgenic plant leaves for 3 days, which was dramatically higher than the 18% mortality recorded in the control group. Moreover, the ingestion of transgenic plants significantly retarded larval growth, and the transcript levels of HaAK were also knocked down by up to 52%. The feeding bioassays further indicated that the inhibition efficiency was correlated with the integrity and concentration of the produced HaAK dsRNA in transgenic plants. These results strongly show that the resistance to H. armigera was improved in transgenic Arabidopsis plants, suggesting that the RNAi targeting of AK has the potential for the control of insect pests. PMID:25552931

  19. Computers and Computer Resources.

    ERIC Educational Resources Information Center

    Bitter, Gary

    1980-01-01

    This resource directory provides brief evaluative descriptions of six popular home computers and lists selected sources of educational software, computer books, and magazines. For a related article on microcomputers in the schools, see p53-58 of this journal issue. (SJL)

  20. Novel clinical applications of dual energy computed tomography.

    PubMed

    Kraśnicki, Tomasz; Podgórski, Przemysław; Guziński, Maciej; Czarnecka, Anna; Tupikowski, Krzysztof; Garcarek, Jerzy; Marek Sąsiadek, Marek

    2012-01-01

    Dual energy CT (DECT) was conceived at the very beginning of the computed tomography era. However the first DECT scanner was developed in 2006. Nowadays there are three different types of DECT available: dual-source CT with 80(100) kVp and 140 kVp tubes (Siemens Medical Solution); dual-layer multi-detector scanner with acquisition 120 or 140kVp (Philips Healthcare); CT unit with one rapid kVp switching source and new detector based on gemstone scintillator materials (GE Healthcare). This article describes the physical background and principles of DECT imaging as well as applications of this innovative method in routine clinical practice (renal stone differentiation, pulmonary perfusion, neuroradiology and metallic implant imaging). The particular applications are illustrated by cases from author's material. PMID:23457140

  1. 120. Back side technical facilities S.R. radar transmitter & computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    120. Back side technical facilities S.R. radar transmitter & computer building no. 102, section II "foundation & first floor plan" - structural, AS-BLT AW 35-46-04, sheet 65, dated 23 January, 1961. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  2. 119. Back side technical facilities S.R. radar transmitter & computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    119. Back side technical facilities S.R. radar transmitter & computer building no. 102, section I "tower plan, sections & details" - structural, AS-BLT AW 35-46-04, sheet 62, dated 23 January, 1961. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  3. 118. Back side technical facilities S.R. radar transmitter & computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    118. Back side technical facilities S.R. radar transmitter & computer building no. 102, "building sections - sheet I" - architectural, AS-BLT AW 35-46-04, sheet 13, dated 23 January, 1961. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  4. 122. Back side technical facilities S.R. radar transmitter & computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    122. Back side technical facilities S.R. radar transmitter & computer building no. 102, section II "elevations & details" - structural, AS-BLT AW 35-46-04, sheet 73, dated 23 January, 1961. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  5. 117. Back side technical facilities S.R. radar transmitter & computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    117. Back side technical facilities S.R. radar transmitter & computer building no. 102, "building sections - sheet I" - architectural, AS-BLT AW 35-46-04, sheet 12, dated 23 January, 1961. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  6. 121. Back side technical facilities S.R. radar transmitter & computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    121. Back side technical facilities S.R. radar transmitter & computer building no. 102, section II "sections & elevations" - structural, AS-BLT AW 35-46-04, sheet 72, dated 23 January, 1961. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  7. Diagnosing pulmonary embolism: new computed tomography applications.

    PubMed

    Nikolaou, Konstantin; Thieme, Sven; Sommer, Wieland; Johnson, Thorsten; Reiser, Maximilian F

    2010-05-01

    Computed tomographic pulmonary angiography has become the standard of care for the evaluation of patients with suspected pulmonary embolism (PE). In addition to the direct depiction or exclusion of a pulmonary embolus in suspected PE, a number of predictive markers have been established to evaluate the patient's prognosis in acute and in chronic PE. An accurate risk stratification based on CT findings is crucial because optimal management, monitoring, and therapeutic strategies depend on the prognosis. With the recent introduction of the so-called "dual-source" CT scanners, that is, a scanner consisting of 2 tubes and 2 detectors mounted orthogonally to each other, different tube voltages can be used simultaneously, resulting in different energies of the emitted x-ray spectra (dual-energy CT; DECT). Initial results have shown that DECT is capable of iodine mapping of the pulmonary parenchyma, reliably depicting the segmental defects in iodine distribution in locations corresponding to embolic vessel occlusions. This study deals with a number of actual topics on PE imaging with multidetector CT and DECT, including the discussion of the relevant imaging findings to assess the patient's prognosis, the potential and additional benefit of dual-energy information on the parenchymal iodine distribution, the optimization of scan protocols including low-radiation dose chest pain protocols, and the discussion on future perspectives of CT in PE patients, such as the role of computer-aided diagnostic tools or the potential of ventilation imaging with DECT. PMID:20463534

  8. Thermodynamic properties of La{sub 1−x}A{sub x}CoO₃ (A=K, Cd, Pr and Nd)

    SciTech Connect

    Thakur, Rasna; Gaur, N.K.

    2013-05-01

    We have calculated the thermal and allied properties of La{sub 1–x}A{sub x}CoO₃ (A=K, Cd, Pr, Nd and 0≤x≤1) as a function of temperature 1 K≤T≤300 K for the first time using Modified Rigid Ion Model (MRIM). The calculated bulk modulus, specific heat, thermal expansion and other thermodynamic properties obtained from MRIM have presented proper interpretation of the experimental data, for monovalent (K⁺), divalent (Cd₂⁺) and trivalent (Pr³⁺ and Nd³⁺) ion-doped LaCoO₃. In addition, the results on the cohesive energy (Φ), molecular force constant (f), Reststrahlen frequency (υ), Debye temperature (θ}) and Gruneisen parameter (γ) are also discussed. - Graphical abstract: Substitution to trivalent La³⁺ site by K⁺ ions increase the thermal expansion (α) whereas Cd²⁺, Pr³⁺ and Nd³⁺ results in decrease of α in La{sub 1–x}A{sub x}CoO₃₋ (A=K, Cd, Pr, Nd). Highlights: • Probably the first report on the specific heat and thermal expansion in La{sub 1–x}A{sub x}CoO₃. • Thermal properties are computed using the MRIM probably for the first time. • Effect of lattice distortions on bulk modulus and thermal properties is presented. • The negative values of cohesive energy show the stability of these compounds.

  9. Enhancement of CD3AK cell proliferation and killing ability by α-Thujone.

    PubMed

    Zhou, Yu; Liu, Jun-quan; Zhou, Zhong-hai; Lv, Xiao-ting; Chen, Yong-qiang; Sun, Lei-qing; Chen, Fu-xing

    2016-01-01

    Thujone is a monoterpene ketone natural substance found mainly in wormwood and sage. Previous studies have shown that Thujone has various pharmacological effects, such as anti-tumor, analgesic, and insecticide. The effect of α-Thujone to human immune cells is still unknown. Our study focuses on investigating the effects and mechanism of α-Thujone to CD3AK (anti- CD3 antibody induced activated killer) cells proliferation and cytotoxicity to colon cancer cell lines. With cell proliferation and FCM assay, it is found that α-Thujone could significantly enhance CD3AK cell proliferation and expression of CD107a in a dose-dependent manner. The cytotoxicity to colon cancer cells detected by CCK-8 assay is also improved. The expressions of TNF-α and FasL detected with ELISA assay were not significantly changed. Mechanically, the study shows that α-Thujone could enhance the expression of p-ERK1/2 and p-Akt. In addition, α-Thujone has no cytotoxicity to HCT116 and SW620 cells proliferation. In a word, α-Thujone enhances CD3AK cell proliferation and cytotoxicity via the improvement of expression of CD107a, p-Akt and p-ERK1/2. PMID:26655741

  10. The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Gu, J.; Bednarz, B.; Caracappa, P. F.; Xu, X. G.

    2009-05-01

    The latest multiple-detector technologies have further increased the popularity of x-ray CT as a diagnostic imaging modality. There is a continuing need to assess the potential radiation risk associated with such rapidly evolving multi-detector CT (MDCT) modalities and scanning protocols. This need can be met by the use of CT source models that are integrated with patient computational phantoms for organ dose calculations. Based on this purpose, this work developed and validated an MDCT scanner using the Monte Carlo method, and meanwhile the pregnant patient phantoms were integrated into the MDCT scanner model for assessment of the dose to the fetus as well as doses to the organs or tissues of the pregnant patient phantom. A Monte Carlo code, MCNPX, was used to simulate the x-ray source including the energy spectrum, filter and scan trajectory. Detailed CT scanner components were specified using an iterative trial-and-error procedure for a GE LightSpeed CT scanner. The scanner model was validated by comparing simulated results against measured CTDI values and dose profiles reported in the literature. The source movement along the helical trajectory was simulated using the pitch of 0.9375 and 1.375, respectively. The validated scanner model was then integrated with phantoms of a pregnant patient in three different gestational periods to calculate organ doses. It was found that the dose to the fetus of the 3 month pregnant patient phantom was 0.13 mGy/100 mAs and 0.57 mGy/100 mAs from the chest and kidney scan, respectively. For the chest scan of the 6 month patient phantom and the 9 month patient phantom, the fetal doses were 0.21 mGy/100 mAs and 0.26 mGy/100 mAs, respectively. The paper also discusses how these fetal dose values can be used to evaluate imaging procedures and to assess risk using recommendations of the report from AAPM Task Group 36. This work demonstrates the ability of modeling and validating an MDCT scanner by the Monte Carlo method, as well as

  11. Non-invasive Detection of Aortic and Coronary Atherosclerosis in Homozygous Familial Hypercholesterolemia by 64 Slice Multi-detector Row Computed Tomography Angiography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector-row ...

  12. Non-invasive detection of aortic and coronary atherosclerosis in homozygous familial hypercholesterolemia by 64 slice multi-detector row computed tomography angiography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector row ...

  13. Differentiation of Malignant and Benign Incidental Breast Lesions Detected by Chest Multidetector-Row Computed Tomography: Added Value of Quantitative Enhancement Analysis

    PubMed Central

    Lin, Yu-Pang; Hsu, Hsian-He; Ko, Kai-Hsiung; Chu, Chi-Ming; Chou, Yu-Ching; Chang, Wei-Chou; Chang, Tsun-Hou

    2016-01-01

    To retrospectively determine the association between breast lesion morphology and malignancy and to determine the optimal value of lesion enhancement (HU, Hounsfield units) to improve the diagnostic accuracy of breast cancer in patients with incidental breast lesions (IBLs). A total of 97 patients with 102 IBLs detected from July 2009 to December 2012 were enrolled in this study. Two radiologists analyzed CT images for the presence of malignancy based on the morphology of the lesions alone and in combination with an enhancement value (HU) analysis. There were 36 malignant and 66 benign IBLs. When the morphology and enhancement values were combined, the sensitivity, specificity, and accuracy were 92%, 97%, and 95%, respectively, for reader 1 and 89%, 94%, and 92%, respectively, for reader 2. The addition of HU values led to correct changes in the diagnosis; specifically, the accuracy of the diagnosis of reader 1 and reader 2 improved by 6.9% and 11.8%, respectively. The addition of the enhancement value (HU) to the CT morphology improved the diagnostic accuracy in the differentiation of malignant from benign IBLs by using the region of interest (ROI) to measure the HU within the most suspicious part of the lesion. PMID:27128524

  14. iAK692: A genome-scale metabolic model of Spirulina platensis C1

    PubMed Central

    2012-01-01

    Background Spirulina (Arthrospira) platensis is a well-known filamentous cyanobacterium used in the production of many industrial products, including high value compounds, healthy food supplements, animal feeds, pharmaceuticals and cosmetics, for example. It has been increasingly studied around the world for scientific purposes, especially for its genome, biology, physiology, and also for the analysis of its small-scale metabolic network. However, the overall description of the metabolic and biotechnological capabilities of S. platensis requires the development of a whole cellular metabolism model. Recently, the S. platensis C1 (Arthrospira sp. PCC9438) genome sequence has become available, allowing systems-level studies of this commercial cyanobacterium. Results In this work, we present the genome-scale metabolic network analysis of S. platensis C1, iAK692, its topological properties, and its metabolic capabilities and functions. The network was reconstructed from the S. platensis C1 annotated genomic sequence using Pathway Tools software to generate a preliminary network. Then, manual curation was performed based on a collective knowledge base and a combination of genomic, biochemical, and physiological information. The genome-scale metabolic model consists of 692 genes, 837 metabolites, and 875 reactions. We validated iAK692 by conducting fermentation experiments and simulating the model under autotrophic, heterotrophic, and mixotrophic growth conditions using COBRA toolbox. The model predictions under these growth conditions were consistent with the experimental results. The iAK692 model was further used to predict the unique active reactions and essential genes for each growth condition. Additionally, the metabolic states of iAK692 during autotrophic and mixotrophic growths were described by phenotypic phase plane (PhPP) analysis. Conclusions This study proposes the first genome-scale model of S. platensis C1, iAK692, which is a predictive metabolic platform

  15. AkP from mushroom Termitomyces clypeatus is a proteoglycan specific protease with apoptotic effect on HepG2.

    PubMed

    Majumder, Rajib; Banik, Samudra Prosad; Khowala, Suman

    2016-10-01

    Termitomyces clypeatus is an edible mushroom, prized for its therapeutic values and as producer of industrially important enzymes. However, the biomedical efficacies of anticancer proteases have not been reported yet. The present study aimed to purify and characterize a serine protease (AkP) from T. clypeatus for investigating cytotoxic potency on HepG2, Hep3B, and compared the effect on normal hepatic L-02 cells. Purification and biochemical characterization of AkP were evaluated by three stage chromatography, 1D/2D-SDS-PAGE, 1D zymography, far-UV CD spectral analysis, N-terminal sequencing, MALDI-TOF/MS-MS analysis and enzyme kinetics studies. AkP could cleave the growth promoting cell surface proteoglycans of HepG2, corroborated by RP-HPLC analysis. AkP (IC50: 75±1.18nM) mediated anti-proliferative activity solely on HepG2 cells through the induction of apoptosis. Augmentation of apoptosis was attributed to up-regulation of p53 and Bax protein expression succeeded by caspase-3 activation. Serine protease inhibitor phenyl methane sulfonyl fluoride (PMSF) inhibited both its proteolytic activity and cytotoxicity on HepG2. These findings demonstrate that AkP could be an effective biomolecule for killing of cancer cells by p53 restoration and surface proteoglycans cleavage. PMID:27180294

  16. Pulmonary Findings on Computed Tomography in Asymptomatic Total Joint Arthroplasty Patients.

    PubMed

    Vigdorchik, Jonathan M; Riesgo, Aldo M; Lincoln, Denis; Markel, David C

    2016-08-01

    An increase in the diagnosis of pulmonary embolus (PE) in the early postoperative period has been attributed to the use of multidetector 64-slice computed tomographic (CT) scans. It was suspected that this finding was the result of marrow or fat emboli that are commonly associated with arthroplasty rather than a true venous thromboembolic phenomenon. The purpose of this study was to determine the baseline pulmonary findings in asymptomatic patients after total joint arthroplasty (TJA). Over a 1-year period, an institutional review board-approved prospective study of 20 asymptomatic patients using a multidetector 64-slice CT scanner was performed. Overall, 15 TKAs and 5 total hip arthroplasties were included for analysis. All of the CT scans were negative for PE. There were no signs of microemboli or fat emboli on any scan. No patient went on to develop a PE at 2 years postoperatively. Despite the fact that emboli are created during TJA, if emboli are seen on a CT scan postoperatively, they should be assumed to be real events with clinical sequelae. If pulmonary symptoms develop postoperatively, they should not simply be assumed to be the result of fat or marrow embolism. PMID:26551068

  17. The role of computed tomography in terminal ballistic analysis.

    PubMed

    Rutty, G N; Boyce, P; Robinson, C E; Jeffery, A J; Morgan, B

    2008-01-01

    Terminal ballistics concerns the science of projectile behaviour within a target and includes wound ballistics that considers what happens when a projectile strikes a living being. A number of soft tissue ballistic simulants have been used to assess the damage to tissue caused by projectiles. Standard assessment of these materials, such as ballistic soap or ordnance gelatine, requires the block to be opened or that a mould to be made to visualize the wound track. This is time consuming and may affect the accuracy of the findings especially if the block dries and alters shape during the process. Therefore, accurate numerical analysis of the permanent or temporary cavity is limited. Computed tomography (CT) potentially offers a quicker non-invasive analysis tool for this task. Four commercially purchased ballistic glycerine soap blocks were used. Each had a single firearm discharged into it from a distance of approximately 15 cm using both gunshot and shotgun projectiles. After discharge, each block was imaged by a modern 16 slice multi-detector CT scanner and analysed using 3-D reconstruction software. Using the anterior-posterior and lateral scout views and the multi-plane reconstructed images, it was possible to visualize the temporary cavity, as well as the fragmentation and dispersal pattern of the projectiles, the distance travelled and angle of dispersal within the block of each projectile or fragment. A virtual cast of the temporary cavity can be also be made. Multi-detector CT with 3-D analysis software is shown to create a reliable permanent record of the projectile path allowing rapid analysis of different firearms and projectiles. PMID:17205351

  18. Improvement of distension and mural visualization of bowel loops using neutral oral contrasts in abdominal computed tomography

    PubMed Central

    Hashemi, Jahanbakhsh; Davoudi, Yasmin; Taghavi, Mina; Pezeshki Rad, Masoud; Moghadam, Amien Mahajeri

    2014-01-01

    AIM: To assess and compare the image quality of 4% sorbitol and diluted iodine 2% (positive oral contrast agent) in abdomino-pelvic multi-detector computed tomography. METHODS: Two-hundred patients, referred to the Radiology Department of a central educational hospital for multi-detector row abdominal-pelvic computed tomography, were randomly divided into two groups: the first group received 1500 mL of 4% sorbitol solution as a neutral contrast agent, while in the second group 1500 mL of meglumin solution as a positive contrast agent was administered in a one-way randomized prospective study. The results were independently reviewed by two radiologists. Luminal distension and mural thickness and mucosal enhancement were compared between the two groups. Statistical analysis of the results was performed by Statistical Package for the Social Sciences software version 16 and the Mann-Whitney test at a confidence level of 95%. RESULTS: Use of neutral oral contrast agent significantly improved visualization of the small bowel wall thickness and mural appearance in comparison with administration of positive contrast agent (P < 0.01). In patients who received sorbitol, the small bowel showed better distention compared with those who received iodine solution as a positive contrast agent (P < 0.05). CONCLUSION: The results of the study demonstrated that oral administration of sorbitol solution allows better luminal distention and visualization of mural features than iodine solution as a positive contrast agent. PMID:25550995

  19. An automated system for lung nodule detection in low-dose computed tomography

    NASA Astrophysics Data System (ADS)

    Gori, I.; Fantacci, M. E.; Preite Martinez, A.; Retico, A.

    2007-03-01

    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 Italian project. One of the main goals of this project is to build a distributed database of lung CT scans in order to enable automated image analysis through a data and cpu GRID infrastructure. The basic modules of our lung-CAD system, a dot-enhancement filter for nodule candidate selection and a neural classifier for false-positive finding reduction, are described. The system was designed and tested for both internal and sub-pleural nodules. The results obtained on the collected database of low-dose thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.

  20. Computed tomography imaging and angiography - principles.

    PubMed

    Kamalian, Shervin; Lev, Michael H; Gupta, Rajiv

    2016-01-01

    The evaluation of patients with diverse neurologic disorders was forever changed in the summer of 1973, when the first commercial computed tomography (CT) scanners were introduced. Until then, the detection and characterization of intracranial or spinal lesions could only be inferred by limited spatial resolution radioisotope scans, or by the patterns of tissue and vascular displacement on invasive pneumoencaphalography and direct carotid puncture catheter arteriography. Even the earliest-generation CT scanners - which required tens of minutes for the acquisition and reconstruction of low-resolution images (128×128 matrix) - could, based on density, noninvasively distinguish infarct, hemorrhage, and other mass lesions with unprecedented accuracy. Iodinated, intravenous contrast added further sensitivity and specificity in regions of blood-brain barrier breakdown. The advent of rapid multidetector row CT scanning in the early 1990s created renewed enthusiasm for CT, with CT angiography largely replacing direct catheter angiography. More recently, iterative reconstruction postprocessing techniques have made possible high spatial resolution, reduced noise, very low radiation dose CT scanning. The speed, spatial resolution, contrast resolution, and low radiation dose capability of present-day scanners have also facilitated dual-energy imaging which, like magnetic resonance imaging, for the first time, has allowed tissue-specific CT imaging characterization of intracranial pathology. PMID:27432657

  1. Computer Music

    NASA Astrophysics Data System (ADS)

    Cook, Perry R.

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and the study of perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.).

  2. Computer Music

    NASA Astrophysics Data System (ADS)

    Cook, Perry

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.). Although most people would think that analog synthesizers and electronic music substantially predate the use of computers in music, many experiments and complete computer music systems were being constructed and used as early as the 1950s.

  3. Accelerated glacier shrinkage in the Ak-Shyirak massif, Inner Tien Shan, during 2003-2013.

    PubMed

    Petrakov, Dmitry; Shpuntova, Alyona; Aleinikov, Alexandr; Kääb, Andreas; Kutuzov, Stanislav; Lavrentiev, Ivan; Stoffel, Markus; Tutubalina, Olga; Usubaliev, Ryskul

    2016-08-15

    The observed increase in summer temperatures and the related glacier downwasting has led to a noticeable decrease of frozen water resources in Central Asia, with possible future impacts on the economy of all downstream countries in the region. Glaciers in the Ak-Shyirak massif, located in the Inner Tien Shan, are not only affected by climate change, but also impacted by the open pit gold mining of the Kumtor Gold Company. In this study, glacier inventories referring to the years 2003 and 2013 were created for the Ak-Shyirak massif based on satellite imagery. The 193 glaciers had a total area of 351.2±5.6km(2) in 2013. Compared to 2003, the total glacier area decreased by 5.9±3.4%. During 2003-2013, the shrinkage rate of Ak-Shyirak glaciers was twice than that in 1977-2003 and similar to shrinkage rates in Tien Shan frontier ranges. We assessed glacier volume in 2013 using volume-area (VA) scaling and GlabTop modelling approaches. Resulting values for the whole massif differ strongly, the VA scaling derived volume is 30.0-26.4km(3) whereas the GlabTop derived volume accounts for 18.8-13.2km(3). Ice losses obtained from both approaches were compared to geodetically-derived volume change. VA scaling underestimates ice losses between 1943 and 2003 whereas GlabTop reveals a good match for eight glaciers for the period 2003-2012. In comparison to radio-echo soundings from three glaciers, the GlabTop model reveals a systematic underestimation of glacier thickness with a mean deviation of 16%. GlabTop tends to significantly underestimate ice thickness in accumulation areas, but tends to overestimate ice thickness in the lowermost parts of glacier snouts. Direct technogenic impact is responsible for about 7% of area and 5% of mass loss for glaciers in the Ak-Shyirak massif during 2003-2013. Therefore the increase of summer temperature seems to be the main driver of accelerated glacier shrinkage in the area. PMID:27100016

  4. JBIR-78 and JBIR-95: phenylacetylated peptides isolated from Kibdelosporangium sp. AK-AA56.

    PubMed

    Izumikawa, Miho; Takagi, Motoki; Shin-Ya, Kazuo

    2012-02-24

    The search for metabolites of Kibdelosporangium sp. AK-AA56 resulted in the discovery of novel N-phenylacetylated peptides, JBIR-78 (1) and JBIR-95 (2). Compounds 1 and 2 were established to be N-phenylacetylated heptapeptides by extensive NMR and HRESIMS analyses. The absolute configuration of the standard amino acids including a cysteic acid moiety was determined using Marfey's method on the acid hydrolysates of 1 and 2. The relative and absolute configurations of a nonstandard amino acid, β-hydroxyleucine, were elucidated using the J-based and modified Mosher's methods, respectively. In an antimicrobial test, 1 showed antibacterial activity against Micrococcus luteus. PMID:22264203

  5. Source mechanics for monochromatic icequakes produced during iceberg calving at Columbia Glacier, AK

    USGS Publications Warehouse

    O'Neel, Shad; Pfeffer, W.T.

    2007-01-01

    Seismograms recorded during iceberg calving contain information pertaining to source processes during calving events. However, locally variable material properties may cause signal distortions, known as site and path effects, which must be eliminated prior to commenting on source mechanics. We applied the technique of horizontal/vertical spectral ratios to passive seismic data collected at Columbia Glacier, AK, and found no dominant site or path effects. Rather, monochromatic waveforms generated by calving appear to result from source processes. We hypothesize that a fluid-filled crack source model offers a potential mechanism for observed seismograms produced by calving, and fracture-processes preceding calving.

  6. Evaluation of a possible sex difference in recombination for the ABO-AK linkage.

    PubMed Central

    Fenger, K; Sorensen, S A

    1975-01-01

    Thirty-five informative families were scored for linkage between the ABO and AK loci. The recombination fractions were estimated separately in females and males and were compared with values reported in the literature. A 1.33:1 ratio for the female:male recombination fraction was obtained by combining all sources, but the difference between the recombination fractions was not significantly different from zero. The present data, combined with those reported earlier, show that the most likely recombination fraction is about 14%. PMID:173186

  7. Missed rib fractures on evaluation of initial chest CT for trauma patients: pattern analysis and diagnostic value of coronal multiplanar reconstruction images with multidetector row CT

    PubMed Central

    Cho, S H; Sung, Y M; Kim, M S

    2012-01-01

    Objective The objective of this study was to review the prevalence and radiological features of rib fractures missed on initial chest CT evaluation, and to examine the diagnostic value of additional coronal images in a large series of trauma patients. Methods 130 patients who presented to an emergency room for blunt chest trauma underwent multidetector row CT of the thorax within the first hour during their stay, and had follow-up CT or bone scans as diagnostic gold standards. Images were evaluated on two separate occasions: once with axial images and once with both axial and coronal images. The detection rates of missed rib fractures were compared between readings using a non-parametric method of clustered data. In the cases of missed rib fractures, the shapes, locations and associated fractures were evaluated. Results 58 rib fractures were missed with axial images only and 52 were missed with both axial and coronal images (p=0.088). The most common shape of missed rib fractures was buckled (56.9%), and the anterior arc (55.2%) was most commonly involved. 21 (36.2%) missed rib fractures had combined fractures on the same ribs, and 38 (65.5%) were accompanied by fracture on neighbouring ribs. Conclusion Missed rib fractures are not uncommon, and radiologists should be familiar with buckle fractures, which are frequently missed. Additional coronal imagescan be helpful in the diagnosis of rib fractures that are not seen on axial images. PMID:22514102

  8. A cardiac phantom study on quantitative correction of coronary calcium score on multi-detector, dual source, and electron beam tomography for velocity, calcification density, and acquisition time

    NASA Astrophysics Data System (ADS)

    Greuter, Marcel J. W.; Groen, Jaap M.; Nicolai, Lieuwe J.; Dijkstra, Hildebrand; Oudkerk, Matthijs

    2009-02-01

    Objective: To quantify the influence of velocity, calcification density and acquisition time on coronary calcium determination using multi-detector CT, dual-source CT and EBT. Materials and Methods: Artificial arteries with four calcifications of increasing density were attached to a robotic arm to which a linear movement was applied between 0 and 120 mm/s (step 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT and EBT using a standard acquisition protocol and the average Agatston score was determined. Results: Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The Agatston score showed a linear dependency on velocity from which a correction factor was derived. This correction factor showed a linear dependency on calcification density (0.92<=R2<=0.95). The slope and offset of this correction factor also showed a linear dependency on acquisition time (0.84<=R2<=0.86). Conclusion: The Agatston score is highly dependent on the average density of individual calcifications. The dependency of the Agatston score on velocity shows a linear behaviour on calcification density. A quantitative method could be derived which corrects the measured calcium score for the influence of velocity, calcification density and acquisition time.

  9. A novel long noncoding RNA AK001796 acts as an oncogene and is involved in cell growth inhibition by resveratrol in lung cancer

    SciTech Connect

    Yang, Qiaoyuan; Xu, Enwu; Dai, Jiabin; Liu, Binbin; Han, Zhiyuan; Wu, Jianjun; Zhang, Shaozhu; Peng, Baoying; Zhang, Yajie; Jiang, Yiguo

    2015-06-01

    Lung cancer is the most common form of cancer throughout the world. The specific targeting of long noncoding RNAs (lncRNAs) by resveratrol opened a new avenue for cancer chemoprevention. In this study, we found that 21 lncRNAs were upregulated and 19 lncRNAs were downregulated in lung cancer A549 cells with 25 μmol/L resveratrol treatment determined by microarray analysis. AK001796, the lncRNA with the most clearly altered expression, was overexpressed in lung cancer tissues and cell lines, but its expression was downregulated in resveratrol-treated lung cancer cells. By monitoring cell proliferation and growth in vitro and tumor growth in vivo, we observed a significant reduction in cell viability in lung cancer cells and a slow growth in the tumorigenesis following AK001796 knockdown. We also found that AK001796 knockdown caused a cell-cycle arrest, with significant increases in the percentage of cells in G{sub 0}/G{sub 1} in lung cancer cells. By using cell cycle pathway-specific PCR arrays, we detected changes in a number of cell cycle-related genes related to lncRNA AK001796 knockdown. We further investigated whether AK001796 participated in the anticancer effect of resveratrol and the results showed that reduced lncRNA AK001796 level potentially impaired the inhibitory effect of resveratrol on cell proliferation. To our knowledge, this is the first study to report the changes in an lncRNA expression profile induced by resveratrol in lung cancer. - Highlights: • LncRNA AK001796 played an oncogenic role in lung carcinogenesis. • LncRNA AK001796 was downregulated in resveratrol-treated lung cancer cells. • LncRNA AK001796 was involved in the inhibition of cell growth by resveratrol.

  10. Pygmalion's Computer.

    ERIC Educational Resources Information Center

    Peelle, Howard A.

    Computers have undoubtedly entered the educational arena, mainly in the areas of computer-assisted instruction (CAI) and artificial intelligence, but whether educators should embrace computers and exactly how they should use them are matters of great debate. The use of computers in support of educational administration is widely accepted.…

  11. 76 FR 36157 - In the Matter of Alaska Industrial X-Ray, Inc., Anchorage, AK; Confirmatory Order Modifying...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... entities participating under 10 CFR 2.315(c), must be filed in accordance with the NRC E-Filing rule (72 FR... Alaska Industrial X-Ray, Inc., Anchorage, AK; Confirmatory Order Modifying License; Effective Immediately I Alaska Industrial X-Ray, Inc. (AIX or Licensee) is the holder of Materials License...

  12. 33 CFR 165.1712 - Safety Zones; Annual Independence Day Firework Displays, Skagway, Haines, and Wrangell, AK.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... regulations contained in 33 CFR 165.23, as well as the following regulations, apply. (2) No vessels, except... Day Firework Displays, Skagway, Haines, and Wrangell, AK. 165.1712 Section 165.1712 Navigation and... Areas Seventeenth Coast Guard District § 165.1712 Safety Zones; Annual Independence Day...

  13. 33 CFR 165.1712 - Safety Zones; Annual Independence Day Firework Displays, Skagway, Haines, and Wrangell, AK.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... regulations contained in 33 CFR 165.23, as well as the following regulations, apply. (2) No vessels, except... Day Firework Displays, Skagway, Haines, and Wrangell, AK. 165.1712 Section 165.1712 Navigation and... Areas Seventeenth Coast Guard District § 165.1712 Safety Zones; Annual Independence Day...

  14. Using macroalgal δ15N bioassay to detect cruise ship waste water effluent inputs in Skagway, AK

    EPA Science Inventory

    Nitrogen stable isotopes are a powerful tool for tracking sources of N to marine ecosystems. I used green macroalgae as a bioassay organism to evaluate if the δ15N signature of cruise ship waste water effluent (CSWWE) could be detected in Skagway Harbor, AK. Opportunistic green...

  15. 78 FR 73109 - Radio Broadcasting Services; Benjamin and Cisco, TX; De Beque, CO; Port Lions, AK; Rule and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-05

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Benjamin and Cisco, TX; De Beque, CO; Port Lions, AK... Commission amends the Table of FM Allotments by removing Channel 221C0 at Port Lions, Alaska; Channel 247C3...(b), the Table of FM Allotments, is amended by: 0 a. Under Alaska, removing Port Lions, Channel...

  16. Results of the Test Program for Replacement of AK-225G Solvent for Cleaning NASA Propulsion Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.; Mitchell, Mark A.

    2016-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon the solvent AsahiKlin AK-225 (hydrochlorofluorocarbon-225ca/cb or HCFC-225ca/cb) and, more recently AK-225G (the single isomer form, HCFC-225cb) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of Class II Ozone Depleting Substances, including AK-225G, was prohibited in the United States by the Clean Air Act. In 2012 through 2014, NASA test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a solvent replacement for AK-225G that is both an effective cleaner and safe for use with oxygen systems. This paper summarizes the tests performed, results, and lessons learned.

  17. 78 FR 7336 - Safety Zone; Alaska Marine Highway System Port Valdez Ferry Terminal, Port Valdez; Valdez, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ... of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed... Federal Register (73 FR 3316). 4. Public Meeting We do not now plan to hold a public meeting. But you may... Ferry Terminal, Port Valdez; Valdez, AK AGENCY: Coast Guard, DHS. ACTION: Notice of Proposed...

  18. A Disk-based Dynamical Mass Estimate for the Young Binary AK Sco

    NASA Astrophysics Data System (ADS)

    Czekala, I.; Andrews, S. M.; Jensen, E. L. N.; Stassun, K. G.; Torres, G.; Wilner, D. J.

    2015-06-01

    We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust in the disk orbiting the pre-main sequence (pre-MS) binary AK Sco. By forward-modeling the disk velocity field traced by CO J = 2–1 line emission, we infer the mass of the central binary, {M}*=2.49+/- 0.10 {M}ȯ , a new dynamical measurement that is independent of stellar evolutionary models. Assuming the disk and binary are co-planar within ∼2°, this disk-based binary mass measurement is in excellent agreement with constraints from radial velocity monitoring of the combined stellar spectra. These ALMA results are also compared with the standard approach of estimating masses from the location of the binary in the Hertzsprung–Russell diagram, using several common pre-MS model grids. These models predict stellar masses that are marginally consistent with our dynamical measurement (at ∼2σ), but are systematically high (by ∼10%). These same models consistently predict an age of 18 ± 1 Myr for AK Sco, in line with its membership in the Upper Centaurus–Lupus association but surprisingly old for it to still host a gas-rich disk. As ALMA accumulates comparable data for large samples of pre-MS stars, the methodology employed here to extract a dynamical mass from the disk rotation curve should prove extraordinarily useful for efforts to characterize the fundamental parameters of early stellar evolution.

  19. Mapping the magnetospheric structure at outburst of the pre-main sequence close binary AK Sco

    NASA Astrophysics Data System (ADS)

    Gomez De Castro, Ana

    2013-10-01

    Pre-main sequence {PMS} binaries are surrounded by circumbinary disks from which matter falls onto both components. The material dragged from the circumbinary disk flows onto each star through independent streams channelled by the variable gravitational field. The action of the bar-like potential is most prominent in high eccentricity systems made of two equal mass stars. AK Sco is a unique PMS system composed of two F5 stars that get as close as 11.3 stellar radii at periastron {e=0.47}. AK Sco is an ideal laboratory to study matter infall in binaries and its role in orbit circularization. Our team has reported recently, the discovery of an unexpected 1.3mHz ultra low frequency {ULF} oscillation in the ultraviolet light curve at periastron passage. The oscillation lasted 0.6% of the orbital period. According to our numerical simulations, the cirscumstellar structures get in contact at periastron producing an accretion outburst that triggered of the oscillation. If confirmed, this would unveil a new mechanism for angular momentum loss during pre-main sequence evolution and a new type of interacting binary. The objective of this project is to identify the source of the oscillation and the physical structure of the accretion flow before, during and after the oscillation is triggered. Since the accretion flow radiates in the ultraviolet range, this study requires an ultraviolet {UV} spectroscopic monitoring.

  20. Detection of Sharp Symmetric Features in the Circumbinary Disk around AK Sco

    NASA Astrophysics Data System (ADS)

    Janson, Markus; Thalmann, Christian; Boccaletti, Anthony; Maire, Anne-Lise; Zurlo, Alice; Marzari, Francesco; Meyer, Michael R.; Carson, Joseph C.; Augereau, Jean-Charles; Garufi, Antonio; Henning, Thomas; Desidera, Silvano; Asensio-Torres, Ruben; Pohl, Adriana

    2016-01-01

    The Search for Planets Orbiting Two Stars survey aims to study the formation and distribution of planets in binary systems by detecting and characterizing circumbinary planets and their formation environments through direct imaging. With the SPHERE Extreme Adaptive Optics instrument, a good contrast can be achieved even at small (<300 mas) separations from bright stars, which enables studies of planets and disks in a separation range that was previously inaccessible. Here, we report the discovery of resolved scattered light emission from the circumbinary disk around the well-studied young double star AK Sco, at projected separations in the ∼13–40 AU range. The sharp morphology of the imaged feature is surprising, given the smooth appearance of the disk in its spectral energy distribution. We show that the observed morphology can be represented either as a highly eccentric ring around AK Sco, or as two separate spiral arms in the disk, wound in opposite directions. The relative merits of these interpretations are discussed, as well as whether these features may have been caused by one or several circumbinary planets interacting with the disk. Based on observations collected at the European Southern Observatory, Chile, under observing program 095.C-0346(B).

  1. Characterization of a GHF45 cellulase, AkEG21, from the common sea hare Aplysia kurodai

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammad; Inoue, Akira; Ojima, Takao

    2014-08-01

    The common sea hare Aplysia kurodai is known to be a good source for the enzymes degrading seaweed polysaccharides. Recently four cellulases, i.e., 95 kDa, 66 kDa, 45 kDa and 21 kDa enzymes, were isolated from A. kurodai (Tsuji et al., PLoS ONE, 8, e65418, 2013). The former three cellulases were regarded as glycosyl-hydrolase-family 9 (GHF9) enzymes, while the 21 kDa cellulase was suggested to be a GHF45 enzyme. The 21 kDa cellulase was significantly heat stable, and appeared to be advantageous in performing heterogeneous expression and protein-engineering study. In the present study, we determined some enzymatic properties of the 21 kDa cellulase and cloned its cDNA to provide the basis for the protein engineering study of this cellulase. The purified 21 kDa enzyme, termed AkEG21 in the present study, hydrolyzed carboxymethyl cellulose with an optimal pH and temperature at 4.5 and 40oC, respectively. AkEG21 was considerably heat-stable, i.e., it was not inactivated by the incubation at 55oC for 30 min. AkEG21 degraded phosphoric-acid-swollen cellulose producing cellotriose and cellobiose as major end products but hardly degraded oligosaccharides smaller than tetrasaccharide. This indicated that AkEG21 is an endolytic ?-1,4-glucanase (EC 3.2.1.4). A cDNA of 1,013 bp encoding AkEG21 was amplified by PCR and the amino-acid sequence of 197 residues was deduced. The sequence comprised the initiation Met, the putative signal peptide of 16 residues for secretion and the catalytic domain of 180 residues, which lined from the N-terminus in this order. The sequence of the catalytic domain showed 47-62% amino-acid identities to those of GHF45 cellulases reported in other mollusks. Both the catalytic residues and the N-glycosylation residues known in other GHF45 cellulases were conserved in AkEG21. Phylogenetic analysis for the amino-acid sequences suggested the close relation between AkEG21 and fungal GHF45 cellulases.

  2. Characterization of a GHF45 cellulase, AkEG21, from the common sea hare Aplysia kurodai

    PubMed Central

    Rahman, Mohammad M.; Inoue, Akira; Ojima, Takao

    2014-01-01

    The common sea hare Aplysia kurodai is known to be a good source for the enzymes degrading seaweed polysaccharides. Recently four cellulases, i.e., 95, 66, 45, and 21 kDa enzymes, were isolated from A. kurodai (Tsuji et al., 2013). The former three cellulases were regarded as glycosyl-hydrolase-family 9 (GHF9) enzymes, while the 21 kDa cellulase was suggested to be a GHF45 enzyme. The 21 kDa cellulase was significantly heat stable, and appeared to be advantageous in performing heterogeneous expression and protein-engineering study. In the present study, we determined some enzymatic properties of the 21 kDa cellulase and cloned its cDNA to provide the basis for the protein engineering study of this cellulase. The purified 21 kDa enzyme, termed AkEG21 in the present study, hydrolyzed carboxymethyl cellulose with an optimal pH and temperature at 4.5 and 40°C, respectively. AkEG21 was considerably heat-stable, i.e., it was not inactivated by the incubation at 55°C for 30 min. AkEG21 degraded phosphoric-acid-swollen cellulose producing cellotriose and cellobiose as major end products but hardly degraded oligosaccharides smaller than tetrasaccharide. This indicated that AkEG21 is an endolytic β-1,4-glucanase (EC 3.2.1.4). A cDNA of 1013 bp encoding AkEG21 was amplified by PCR and the amino-acid sequence of 197 residues was deduced. The sequence comprised the initiation Met, the putative signal peptide of 16 residues for secretion and the catalytic domain of 180 residues, which lined from the N-terminus in this order. The sequence of the catalytic domain showed 47–62% amino-acid identities to those of GHF45 cellulases reported in other mollusks. Both the catalytic residues and the N-glycosylation residues known in other GHF45 cellulases were conserved in AkEG21. Phylogenetic analysis for the amino-acid sequences suggested the close relation between AkEG21 and fungal GHF45 cellulases. PMID:25147784

  3. Development and Reproducibility of a Computed Tomography–Based Measurement for Upper Body Subcutaneous Neck Fat

    PubMed Central

    Rosenquist, Klara J.; Therkelsen, Kate E.; Massaro, Joseph M.; Hoffmann, Udo; Fox, Caroline S.

    2014-01-01

    Background Upper body subcutaneous neck fat (UBSF) is a unique fat depot anatomically separate from visceral abdominal fat that appears to be associated with cardiometabolic risk above and beyond generalized adiposity. We sought to develop a protocol to quantify UBSF using multidetector computed tomography measurements. Methods and Results Protocol development was performed in participants from the Framingham Heart Study who had participated in the multidetector computed tomography scanning substudy, consisting of chest scans. Volumetric assessment of UBSF was defined by 40 contiguous 0.625‐mm slices superior to the body of the sternum. The reader manually traced the chest to identify total neck fat. Breast tissue exterior to the chest wall was excluded. Subcutaneous and visceral fat volumes were obtained using standard protocols. Age‐ and sex‐adjusted Pearson correlation coefficients were used to assess the association among UBSF, traditional adiposity measures, and cardiometabolic risk factors. Inter‐ and intrareader reproducibility was assessed using intraclass correlation coefficients. Volumetric assessments were obtained in 92 participants because 8 scans were not readable (51% women; mean age: 59 years [women], 58 years [men]). The mean volume of UBSF was 310 cm3 for women and 345 cm3 for men. Intra‐ and interreader class correlation coefficients were 0.99 and 0.99, respectively. UBSF was correlated with waist circumference (r=0.90), neck circumference (r=0.75), body mass index (r=0.89), subcutaneous adipose tissue (r=0.87), and visceral adipose tissue (r=0.86). Conclusions UBSF can be quantified reproducibly using computed tomography in a community‐dwelling sample from the Framingham Heart Study. PMID:25523152

  4. Coronary Computed Tomography Angiography of Spontaneous Coronary Artery Dissection: A Case Report and Review of the Literature

    PubMed Central

    Torres-Ayala, Stephanie C.; Maldonado, Jose; Scott Bolton, J.; Bhalla, Sanjeev

    2015-01-01

    Patient: Male, 23 Final Diagnosis: Spontaneous coronary artery dissection Symptoms: Chest discomfort • chest pain Medication: — Clinical Procedure: Coronary computed tomography angiography Specialty: Radiology Objective: Rare disease Background: Multidetector computed tomography (MDCT) has gained wide acceptance in the evaluation of the cardiovascular system. Of particular clinical interest is its ability to non-invasively evaluate coronary arteries in patients presenting to the emergency room. In acute coronary syndromes, myocardial ischemia is most often caused by atherosclerosis. We present a case of a rare cause of acute coronary syndrome, spontaneous coronary artery dissection (SCAD), which was initially evaluated with MDCT and followed by intravascular ultrasound (IVUS) and invasive coronary angiography (ICA). We discuss the findings and role of each modality with particular attention to coronary computed tomographic angiography (CCTA) in the diagnosis and management of SCAD. As the use of CCTA in the emergency department continues to rise, radiologists must become familiar with CT appearance of SCAD. Case Report: We report the multidetector computed tomography (MDCT), intravascular ultrasound (IVUS), and invasive coronary angiography (ICA) findings in a case of spontaneous coronary artery dissection of the left anterior descending artery in a previously healthy 23-year-old man. The role of coronary computed tomographic angiography (CCTA) in diagnosis and management of this potentially life-threatening condition is discussed. Conclusions: In the clinical setting of acute coronary syndrome, SCAD must be a consideration, particularly in young patients without clear risk factors for coronary artery disease and in women in the peripartum period. CCTA is a very helpful diagnostic tool to diagnose the condition in a non-invasive manner and to follow up after treatment. PMID:25738889

  5. Computational dosimetry

    SciTech Connect

    Siebert, B.R.L.; Thomas, R.H.

    1996-01-01

    The paper presents a definition of the term ``Computational Dosimetry`` that is interpreted as the sub-discipline of computational physics which is devoted to radiation metrology. It is shown that computational dosimetry is more than a mere collection of computational methods. Computational simulations directed at basic understanding and modelling are important tools provided by computational dosimetry, while another very important application is the support that it can give to the design, optimization and analysis of experiments. However, the primary task of computational dosimetry is to reduce the variance in the determination of absorbed dose (and its related quantities), for example in the disciplines of radiological protection and radiation therapy. In this paper emphasis is given to the discussion of potential pitfalls in the applications of computational dosimetry and recommendations are given for their avoidance. The need for comparison of calculated and experimental data whenever possible is strongly stressed.

  6. COMPUTATIONAL TOXICOLOGY

    EPA Science Inventory

    Over the last several years, there has been increased pressure to utilize novel technologies derived from computational chemistry, molecular biology and systems biology in toxicological risk assessment. This new area has been referred to as "Computational Toxicology". Our resear...

  7. Cloud Computing

    SciTech Connect

    Pete Beckman and Ian Foster

    2009-12-04

    Chicago Matters: Beyond Burnham (WTTW). Chicago has become a world center of "cloud computing." Argonne experts Pete Beckman and Ian Foster explain what "cloud computing" is and how you probably already use it on a daily basis.

  8. Computer Recreations.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1989-01-01

    Reviews the performance of computer programs for writing poetry and prose, including MARK V. SHANEY, MELL, POETRY GENERATOR, THUNDER THOUGHT, and ORPHEUS. Discusses the writing principles of the programs. Provides additional information on computer magnification techniques. (YP)

  9. Computational Toxicology

    EPA Science Inventory

    Computational toxicology’ is a broad term that encompasses all manner of computer-facilitated informatics, data-mining, and modeling endeavors in relation to toxicology, including exposure modeling, physiologically based pharmacokinetic (PBPK) modeling, dose-response modeling, ...

  10. DNA computing.

    PubMed

    Gibbons, A; Amos, M; Hodgson, D

    1997-02-01

    DNA computation is a novel and exciting recent development at the interface of computer science and molecular biology. We describe the current activity in this field following the seminal work of Adleman, who recently showed how techniques of molecular biology may be applied to the solution of a computationally intractable problem. PMID:9013647

  11. Computer Starters!

    ERIC Educational Resources Information Center

    Instructor, 1983

    1983-01-01

    Instructor's Computer-Using Teachers Board members give practical tips on how to get a classroom ready for a new computer, introduce students to the machine, and help them learn about programing and computer literacy. Safety, scheduling, and supervision requirements are noted. (PP)

  12. Computer Corner.

    ERIC Educational Resources Information Center

    Hampel, Paul J.

    1984-01-01

    Presents: (1) a computer program which will change a fraction into a decimal; (2) a program in which students supply missing lines to create the output given; and (3) suggestions for adding computer awareness to classrooms, including use of used punch cards and old computer-generated printouts. (JN)

  13. Computer Literacy.

    ERIC Educational Resources Information Center

    San Marcos Unified School District, CA.

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: After viewing many computer-literacy programs, we believe San Marcos Junior High School has developed a unique program which will truly develop computer literacy. Our hope is to give all students a comprehensive look at computers as they go through their two years here. They will not only learn the…

  14. Computer Literacy.

    ERIC Educational Resources Information Center

    Hunter, Beverly

    The concept of computer literacy is examined as it applies to two-year colleges. The paper begins with definitions of the term, emphasizing the skills, knowledge, and attitudes toward computers that are considered criteria for computer literacy. The paper continues by describing a conference at which educators attempted to visualize the technology…

  15. Computer Manual.

    ERIC Educational Resources Information Center

    Illinois State Office of Education, Springfield.

    This manual designed to provide the teacher with methods of understanding the computer and its potential in the classroom includes four units with exercises and an answer sheet. Unit 1 covers computer fundamentals, the mini computer, programming languages, an introduction to BASIC, and control instructions. Variable names and constants described…

  16. Salt bridge residues between I-Ak dimer of dimers alpha-chains modulate antigen presentation.

    PubMed

    Yadati, S; Nydam, T; Demian, D; Wade, T K; Gabriel, J L; Barisas, B G; Wade, W F

    1999-03-15

    Class II dimers of dimers are predicted to have functional significance in antigen presentation. The putative contact amino acids of the I-Ak class II dimer of dimers have been identified by molecular modeling based on the DR1 crystal structure (Nydam et al., Int. Immunol. 10, 1237,1998). We have previously reported the role in antigen presentation of dimer of dimers contact amino acids located in the C-terminal domains of the alpha- and beta-chains of class II. Our calculations show that residues Ealpha89 and Ralpha145 in the alpha2-domain form an inter alpha-chain salt bridge between pairs of alphabeta-heterodimers. Other residues, Qalpha92 and Nalpha115, may be involved in close association in that part of the alpha-chain. We investigated the role of these amino acids on class II expression and antigen presentation. Class II composed of an Ealpha89K substituted alpha-chain paired with a wt beta-chain exhibited inhibited antigen presentation and expression of alpha-chain serologic epitopes. In contrast, mutation of Ralpha145E had less affect on antigen presentation and did not affect I-Ak serologic epitopes. Interchanging charges of the salt bridge residues by expressing both Ralpha145E and Ealpha89K on the same chain obviated the large negative effect of the Ealpha89K mutation on antigen presentation but not on the serologic epitopes. Our results are similar for those reported for mutation of DR3's inter-chain salt bridge with the exception that double mutants did not moderate the DR3 defect. Interestingly, the amino acids differences between I-A and DR change the location of the inter-chain salt bridges. In DR1 these residues are located at positions Ealpha88 and Kalpha111; in I-Ak these residues are located at position Ealpha89 and Ralpha145. Inter alpha-chain salt bridges are thus maintained in various class II molecules by amino acids located in different parts of the alpha2-domain. This conservation of structure suggests that considerable functional

  17. Demonstrating the origin of cardiac air embolism using post-mortem computed tomography; an illustrated case.

    PubMed

    Saunders, Sarah; Kotecha, Deepjay; Morgan, Bruno; Raj, Vimal; Rutty, Guy

    2011-03-01

    An 83 year old female was found dead in her home. The deceased had been struck repeatedly to the head with at least one weapon, one of which was a hammer. The deceased had suffered both penetrating and non-penetrating blunt trauma to the head as a result of the assault. A multi-detector computed tomography (MDCT) scan was undertaken approximately 12h after death prior to the autopsy examination. This demonstrated the presence of a cardiac air embolus and continuity between the air embolus and the penetrating head injury. Air within the heart is a recognised post-mortem artefact frequently seen on MDCT scans and a common pitfall for inexperienced cadaveric MDCT reporters. This case builds upon a previous report by Kauczor, illustrating how MDCT can be used to demonstrate the origin and route of ingress of a genuine air embolism to the heart. PMID:21131225

  18. Usefulness and limitations of postmortem computed tomography in forensic analysis of gunshot injuries: Three case reports.

    PubMed

    Usui, Akihito; Kawasumi, Yusuke; Hosokai, Yoshiyuki; Kozakai, Masataka; Saito, Haruo; Funayama, Masato

    2016-01-01

    Gunshot injury has always been an important field of investigation in postmortem forensic radiology. The localization and retrieval of the bullet and of potentially important fragments are vital to these cases. Using postmortem multidetector-row computed tomography (MDCT) prior to forensic autopsy, we sought to illustrate the importance of this modality in the noninvasive characterization of gunshot wounds. We obtained and analyzed MDCT images in three cases of gunshot wounds (accidental close-range shotgun shooting, suicidal contact gunshot to the head and accidental long-range buckshot shooting). We discuss the value of postmortem MDCT findings in gunshot wound cases by comparing with forensic autopsy findings in Japan, a developing country with miserably low autopsy rate. PMID:26832386

  19. Spontaneous pneumomediastinum and Macklin effect: Overview and appearance on computed tomography.

    PubMed

    Murayama, Sadayuki; Gibo, Shinji

    2014-11-28

    Spontaneous pneumomediastinum (SPM) is described as free air or gas located within the mediastinum that is not associated with any noticeable cause such as chest trauma. SPM has been associated with many conditions and triggers, including bronchial asthma, diabetic ketoacidosis, forceful straining during exercise, inhalation of drugs, as well as other activities associated with the Valsalva maneuver. The Macklin effect appears on thoracic computed tomography (CT) as linear collections of air contiguous to the bronchovascular sheaths. With the recent availability of multidetector-row CT, the Macklin effect has been seen in the clinical setting more frequently than expected. The aim of this review article is to describe the CT imaging spectrum of the Macklin effect in patients with SPM, focusing on the common appearance of the Macklin effect, pneumorrhachis, and persistent SPM with pneumatocele. PMID:25431639

  20. Autophosphorylation at Thr279 of Entamoeba histolytica atypical kinase EhAK1 is required for activity and regulation of erythrophagocytosis.

    PubMed

    Mansuri, M Shahid; Babuta, Mrigya; Ali, Mohammad Sabir; Bharadwaj, Ravi; Deep jhingan, Gagan; Gourinath, Samudrala; Bhattacharya, Sudha; Bhattacharya, Alok

    2016-01-01

    Phagocytosis plays a key role in survival and pathogenicity of Entamoeba histolytica. We have recently demonstrated that an atypical kinase EhAK1 is involved in phagocytosis in this parasite. It is recruited to the phagocytic cups through interaction with EhCaBP1. EhAK1 manipulates actin dynamics by multiple mechanisms including phosphorylation of G-actin. Biochemical analysis showed that EhAK1 is a serine/threonine kinase with broad ion specificity and undergoes multiple trans-autophosphorylation. Three autophosphorylation sites were identified by mass spectrometry. Out of these Thr279 appears to be involved in both autophosphorylation as well as substrate phosphorylation. Over expression of the mutant Thr279A inhibited erythrophagocytosis showing dominant negative phenotype. Multiple alignments of different kinases including alpha kinases displayed conserved binding sites that are thought to be important for function of the protein. Mutation studies demonstrated the importance of some of these binding sites in kinase activity. Binding studies with fluorescent-ATP analogs supported our prediction regarding ATP binding site based on sequence alignment. In conclusion, EhAK1 has multiple regulatory features and enrichment of EhAK1 at the site of phagocytosis stimulates trans-autophosphorylation reaction that increases kinase activity resulting in enhanced actin dynamics and phagocytosis. Some of the properties of EhAK1 are similar to that seen in alpha kinases. PMID:26739245

  1. Autophosphorylation at Thr279 of Entamoeba histolytica atypical kinase EhAK1 is required for activity and regulation of erythrophagocytosis

    PubMed Central

    Mansuri, M Shahid; Babuta, Mrigya; Ali, Mohammad Sabir; Bharadwaj, Ravi; jhingan, Gagan Deep; Gourinath, Samudrala; Bhattacharya, Sudha; Bhattacharya, Alok

    2016-01-01

    Phagocytosis plays a key role in survival and pathogenicity of Entamoeba histolytica. We have recently demonstrated that an atypical kinase EhAK1 is involved in phagocytosis in this parasite. It is recruited to the phagocytic cups through interaction with EhCaBP1. EhAK1 manipulates actin dynamics by multiple mechanisms including phosphorylation of G-actin. Biochemical analysis showed that EhAK1 is a serine/threonine kinase with broad ion specificity and undergoes multiple trans-autophosphorylation. Three autophosphorylation sites were identified by mass spectrometry. Out of these Thr279 appears to be involved in both autophosphorylation as well as substrate phosphorylation. Over expression of the mutant Thr279A inhibited erythrophagocytosis showing dominant negative phenotype. Multiple alignments of different kinases including alpha kinases displayed conserved binding sites that are thought to be important for function of the protein. Mutation studies demonstrated the importance of some of these binding sites in kinase activity. Binding studies with fluorescent-ATP analogs supported our prediction regarding ATP binding site based on sequence alignment. In conclusion, EhAK1 has multiple regulatory features and enrichment of EhAK1 at the site of phagocytosis stimulates trans-autophosphorylation reaction that increases kinase activity resulting in enhanced actin dynamics and phagocytosis. Some of the properties of EhAK1 are similar to that seen in alpha kinases. PMID:26739245

  2. Quantum Computing

    NASA Astrophysics Data System (ADS)

    Steffen, Matthias

    2013-03-01

    Quantum mechanics plays a crucial role in many day-to-day products, and has been successfully used to explain a wide variety of observations in Physics. While some quantum effects such as tunneling limit the degree to which modern CMOS devices can be scaled to ever reducing dimensions, others may potentially be exploited to build an entirely new computing architecture: The quantum computer. In this talk I will review several basic concepts of a quantum computer. Why quantum computing and how do we do it? What is the status of several (but not all) approaches towards building a quantum computer, including IBM's approach using superconducting qubits? And what will it take to build a functional machine? The promise is that a quantum computer could solve certain interesting computational problems such as factoring using exponentially fewer computational steps than classical systems. Although the most sophisticated modern quantum computing experiments to date do not outperform simple classical computations, it is increasingly becoming clear that small scale demonstrations with as many as 100 qubits are beginning to be within reach over the next several years. Such a demonstration would undoubtedly be a thrilling feat, and usher in a new era of controllably testing quantum mechanics or quantum computing aspects. At the minimum, future demonstrations will shed much light on what lies ahead.

  3. Computer sciences

    NASA Technical Reports Server (NTRS)

    Smith, Paul H.

    1988-01-01

    The Computer Science Program provides advanced concepts, techniques, system architectures, algorithms, and software for both space and aeronautics information sciences and computer systems. The overall goal is to provide the technical foundation within NASA for the advancement of computing technology in aerospace applications. The research program is improving the state of knowledge of fundamental aerospace computing principles and advancing computing technology in space applications such as software engineering and information extraction from data collected by scientific instruments in space. The program includes the development of special algorithms and techniques to exploit the computing power provided by high performance parallel processors and special purpose architectures. Research is being conducted in the fundamentals of data base logic and improvement techniques for producing reliable computing systems.

  4. Computer software.

    PubMed

    Rosenthal, L E

    1986-10-01

    Software is the component in a computer system that permits the hardware to perform the various functions that a computer system is capable of doing. The history of software and its development can be traced to the early nineteenth century. All computer systems are designed to utilize the "stored program concept" as first developed by Charles Babbage in the 1850s. The concept was lost until the mid-1940s, when modern computers made their appearance. Today, because of the complex and myriad tasks that a computer system can perform, there has been a differentiation of types of software. There is software designed to perform specific business applications. There is software that controls the overall operation of a computer system. And there is software that is designed to carry out specialized tasks. Regardless of types, software is the most critical component of any computer system. Without it, all one has is a collection of circuits, transistors, and silicone chips. PMID:3536223

  5. Computer Literacy: Teaching Computer Ethics.

    ERIC Educational Resources Information Center

    Troutner, Joanne

    1986-01-01

    Suggests learning activities for teaching computer ethics in three areas: (1) equal access; (2) computer crime; and (3) privacy. Topics include computer time, advertising, class enrollments, copyright law, sabotage ("worms"), the Privacy Act of 1974 and the Freedom of Information Act of 1966. (JM)

  6. Assessment of AK (Above Knee) Prosthesis with Different Ankle Assembly Using GRF Pattern in Stance Phase

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Min; Kim, Sung-Jae; Bae, Ha-Suk

    In this study, ground reaction force (GRF), absolute symmetry index (ASI) and coefficient of variation (CV) of fixed, single-axis and multi-axis prosthetic ankle assemblies were investigated by biomechanical evaluation of above knee amputees. In the experiments, 37 normal male volunteers, two male and two female Above Knee (AK) amputees GRF data were tested with fixed, single-axis and multi-axis prosthetic ankle assembly. A gait analysis was carried out to derive the ratio of GRF to weight as the percentage of total stance phase for ten points. The results showed that fixed-axis ankle assembly was superior to other two ankle assemblies for forwarding and braking forces. Multi-axis ankle was relatively superior to other two ankle assemblies for gait balancing and movement of the mass center. Single-axis ankle was relatively superior to the other two ankle assemblies for CV and ASI of GRF.

  7. Sinulaflexiolides A-K, cembrane-type diterpenoids from the chinese soft coral Sinularia flexibilis.

    PubMed

    Wen, Ting; Ding, Yi; Deng, Zhiwei; van Ofwegen, Leen; Proksch, Peter; Lin, Wenhan

    2008-07-01

    A bioassay-guided fractionation and chemical examination of the soft coral Sinularia flexibilis resulted in the isolation and characterization of sinulaflexiolides A-K (1-11), along with sinulariolone (12), 5-dehydrosinularolide (13), capillolide (14), sinulariolide (15), 5,8-epoxy-9-acetoxysinulariolide (16), flexibilide (17), dihydroflexibilide (18), and the enantiomer of 14-deoxycrassin (19). Their structures were determined on the basis of extensive spectroscopic (IR, MS, 2D NMR) data analysis and by comparison with spectroscopic data reported in the literature. Sinulaflexiolides D and E showed selective inhibitory activity against the gastric gland carcinoma cell line BGC-823 at 8.5 and 0.12 microM, respectively. PMID:18553926

  8. Tectonic geomorphology of a large normal fault: Akşehir fault, SW Turkey

    NASA Astrophysics Data System (ADS)

    Topal, Savaş; Keller, Edward; Bufe, Aaron; Koçyiğit, Ali

    2016-04-01

    In order to better understand the activity of the Akşehir normal fault in SW Turkey and the associated seismic hazard, we investigated the tectonic geomorphology of a 60-km stretch of the 100-km-long Akşehir fault block. The fault can be separated into seven geomorphic segments (1 to 7 from NW to SE) along the mountain front. Segment length varies from about 9 to 14 km, and relief of the horst block varies from about 0.6 km in the SE to 1.0 km in the NW. Analysis of the tectonic geomorphology of 32 drainage basins and mountain front facets using a combination of geomorphic indices reveals a general pattern of high slip rates in the northern and central segments and low slip rates in the southern, probably older, segments. We show that mountain front sinuosity varies from about 1.1 to 1.4 on segments S1-S6 to 2.4 on segment S7, suggesting that the six northern segments are more active than the southernmost segment. Similarly, χ analysis and slope-area analysis of streams reveal a pattern of steepest channels draining the central and northern segments of the horst. The ratio of valley floor width to valley height varies from 0.2 to 0.6, which are typical values for tectonically active mountain fronts; and alluvial fans along segments S1, S2, and S4 are back-tilted. Finally, we show that (1) shapes of the ~ 100-900m high mountain front facets are mostly triangular (~ 80%) and partly trapezoidal (~ 20%); (2) facet slopes range from 6 to 22°; (3) facets at the NW and SE segment ends are larger than the intervening facets; and (4) steepest facets occur along the central segments. Uplift rates estimated from the slope of mountain front facets range from about 0.06 m/ky on the southernmost fault segment (S7) to 0.23 m/ky on the more central S5 and 0.16 m/ky on the northern segment (S1). The estimated pattern of uplift is consistent with the pattern of geomorphic indices. The vertical relief of the facets suggests that uplift of the mountain front initiated in the late

  9. Neurotransmitter receptor density changes in Pitx3ak mice--a model relevant to Parkinson's disease.

    PubMed

    Cremer, J N; Amunts, K; Graw, J; Piel, M; Rösch, F; Zilles, K

    2015-01-29

    Parkinson's disease (PD) is the second most common neurodegenerative disorder, characterized by alterations of nigrostriatal dopaminergic neurotransmission. Compared to the wealth of data on the impairment of the dopamine system, relatively limited evidence is available concerning the role of major non-dopaminergic neurotransmitter systems in PD. Therefore, we comprehensively investigated the density and distribution of neurotransmitter receptors for glutamate, GABA, acetylcholine, adrenaline, serotonin, dopamine and adenosine in brains of homozygous aphakia mice being characterized by mutations affecting the Pitx3 gene. This genetic model exhibits crucial hallmarks of PD on the neuropathological, symptomatic and pharmacological level. Quantitative receptor autoradiography was used to characterize 19 different receptor binding sites in eleven brain regions in order to understand receptor changes on a systemic level. We demonstrated striking differential changes of neurotransmitter receptor densities for numerous receptor types and brain regions, respectively. Most prominent, a strong up-regulation of GABA receptors and associated benzodiazepine binding sites in different brain regions and concomitant down-regulations of striatal nicotinic acetylcholine and serotonergic receptor densities were found. Furthermore, the densities of glutamatergic kainate, muscarinic acetylcholine, adrenergic α1 and dopaminergic D2/D3 receptors were differentially altered. These results present novel insights into the expression of neurotransmitter receptors in Pitx3(ak) mice supporting findings on PD pathology in patients and indicating on the possible underlying mechanisms. The data suggest Pitx3(ak) mice as an appropriate new model to investigate the role of neurotransmitter receptors in PD. Our study highlights the relevance of non-dopaminergic systems in PD and for the understanding of its molecular pathology. PMID:25451278

  10. Pediatric computed tomographic angiography: imaging the cardiovascular system gently.

    PubMed

    Hellinger, Jeffrey C; Pena, Andres; Poon, Michael; Chan, Frandics P; Epelman, Monica

    2010-03-01

    Whether congenital or acquired, timely recognition and management of disease is imperative, as hemodynamic alterations in blood flow, tissue perfusion, and cellular oxygenation can have profound effects on organ function, growth and development, and quality of life for the pediatric patient. Ensuring safe computed tomographic angiography (CTA) practice and "gentle" pediatric imaging requires the cardiovascular imager to have sound understanding of CTA advantages, limitations, and appropriate indications as well as strong working knowledge of acquisition principles and image post processing. From this vantage point, CTA can be used as a useful adjunct along with the other modalities. This article presents a summary of dose reduction CTA methodologies along with techniques the authors have employed in clinical practice to achieve low-dose and ultralow-dose exposure in pediatric CTA. CTA technical principles are discussed with an emphasis on the low-dose methodologies and safe contrast medium delivery strategies. Recommended parameters for currently available multidetector-row computed tomography scanners are summarized alongside recommended radiation and contrast medium parameters. In the second part of the article an overview of pediatric CTA clinical applications is presented, illustrating low-dose and ultra-low dose techniques, with an emphasis on the specific protocols. PMID:20609882

  11. Computational psychiatry

    PubMed Central

    Montague, P. Read; Dolan, Raymond J.; Friston, Karl J.; Dayan, Peter

    2013-01-01

    Computational ideas pervade many areas of science and have an integrative explanatory role in neuroscience and cognitive science. However, computational depictions of cognitive function have had surprisingly little impact on the way we assess mental illness because diseases of the mind have not been systematically conceptualized in computational terms. Here, we outline goals and nascent efforts in the new field of computational psychiatry, which seeks to characterize mental dysfunction in terms of aberrant computations over multiple scales. We highlight early efforts in this area that employ reinforcement learning and game theoretic frameworks to elucidate decision-making in health and disease. Looking forwards, we emphasize a need for theory development and large-scale computational phenotyping in human subjects. PMID:22177032

  12. Computational aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Deiwert, George S.; Green, Michael J.

    1987-01-01

    Computational aerothermodynamics (CAT) has in the past contributed to the understanding of real-gas flows encountered by hypervelocity reentry vehicles. With advances in computational fluid dynamics, in the modeling of high temperature phenomena, and in computer capability, CAT is an enabling technology for the design of many future space vehicles. An overview of the current capabilities of CAT is provided by describing available methods and their applications. Technical challenges that need to be met are discussed.

  13. Estimation of computed tomography dose index in cone beam computed tomography: MOSFET measurements and Monte Carlo simulations.

    PubMed

    Kim, Sangroh; Yoshizumi, Terry; Toncheva, Greta; Yoo, Sua; Yin, Fang-Fang; Frush, Donald

    2010-05-01

    To address the lack of accurate dose estimation method in cone beam computed tomography (CBCT), we performed point dose metal oxide semiconductor field-effect transistor (MOSFET) measurements and Monte Carlo (MC) simulations. A Varian On-Board Imager (OBI) was employed to measure point doses in the polymethyl methacrylate (PMMA) CT phantoms with MOSFETs for standard and low dose modes. A MC model of the OBI x-ray tube was developed using BEAMnrc/EGSnrc MC system and validated by the half value layer, x-ray spectrum and lateral and depth dose profiles. We compared the weighted computed tomography dose index (CTDIw) between MOSFET measurements and MC simulations. The CTDIw was found to be 8.39 cGy for the head scan and 4.58 cGy for the body scan from the MOSFET measurements in standard dose mode, and 1.89 cGy for the head and 1.11 cGy for the body in low dose mode, respectively. The CTDIw from MC compared well to the MOSFET measurements within 5% differences. In conclusion, a MC model for Varian CBCT has been established and this approach may be easily extended from the CBCT geometry to multi-detector CT geometry. PMID:20386198

  14. Computer Software.

    ERIC Educational Resources Information Center

    Kay, Alan

    1984-01-01

    Discusses the nature and development of computer software. Programing, programing languages, types of software (including dynamic spreadsheets), and software of the future are among the topics considered. (JN)

  15. Computed Tomography

    NASA Astrophysics Data System (ADS)

    Castellano, Isabel; Geleijns, Jacob

    After its clinical introduction in 1973, computed tomography developed from an x-ray modality for axial imaging in neuroradiology into a versatile three dimensional imaging modality for a wide range of applications in for example oncology, vascular radiology, cardiology, traumatology and even in interventional radiology. Computed tomography is applied for diagnosis, follow-up studies and screening of healthy subpopulations with specific risk factors. This chapter provides a general introduction in computed tomography, covering a short history of computed tomography, technology, image quality, dosimetry, room shielding, quality control and quality criteria.

  16. Development of adaptive noise reduction filter algorithm for pediatric body images in a multi-detector CT

    NASA Astrophysics Data System (ADS)

    Nishimaru, Eiji; Ichikawa, Katsuhiro; Okita, Izumi; Ninomiya, Yuuji; Tomoshige, Yukihiro; Kurokawa, Takehiro; Ono, Yutaka; Nakamura, Yuko; Suzuki, Masayuki

    2008-03-01

    Recently, several kinds of post-processing image filters which reduce the noise of computed tomography (CT) images have been proposed. However, these image filters are mostly for adults. Because these are not very effective in small (< 20 cm) display fields of view (FOV), we cannot use them for pediatric body images (e.g., premature babies and infant children). We have developed a new noise reduction filter algorithm for pediatric body CT images. This algorithm is based on a 3D post-processing in which the output pixel values are calculated by nonlinear interpolation in z-directions on original volumetric-data-sets. This algorithm does not need the in-plane (axial plane) processing, so the spatial resolution does not change. From the phantom studies, our algorithm could reduce SD up to 40% without affecting the spatial resolution of x-y plane and z-axis, and improved the CNR up to 30%. This newly developed filter algorithm will be useful for the diagnosis and radiation dose reduction of the pediatric body CT images.

  17. Bloodstain characterization in the EAP, Hp, Hb, AK and Glo I typing systems using minigels and the PhastSystem.

    PubMed

    Shutler, G G; Tompkins, D C

    1988-10-01

    Application of minigels and the PhastSystem to obtain phenotyping results from bloodstains in the EAP, Hp, AK, and Glo I typing systems was investigated. Nonequilibrium isoelectric focusing with 4-6.5 PhastGel produced readily interpretable phenotypes in the EAP typing system. Both 4-6.5 and 5-8 PhastGel produced AK typing system phenotypes using nonequilibrium isoelectric focusing conditions. The 8-25% PAG PhastGel developed by two staining techniques allowed discrimination of phenotypes for the Hp typing system. Phenotypes from the Glo I typing system were also obtained with this gel type. Variant haemoglobins could be detected on pH 5-8 PhastGel using isoelectric focusing conditions. Much potential for standardized, rapid phenotyping of bloodstains was found to exist utilizing the PhastSystem. PMID:2974826

  18. Emergent Kondo Lattice Behavior in Iron-Based Superconductors AFe_{2}As_{2} (A=K, Rb, Cs).

    PubMed

    Wu, Y P; Zhao, D; Wang, A F; Wang, N Z; Xiang, Z J; Luo, X G; Wu, T; Chen, X H

    2016-04-01

    Here, we experimentally study the origin of d-electron heavy fermion (HF) behavior in iron-based superconductors (FeSCs) AFe_{2}As_{2} (A=K, Rb, Cs). Nuclear magnetic resonance on ^{75}As reveals a universal coherent-incoherent crossover with a characteristic temperature T^{*}. Below T^{*}, a so-called "Knight shift anomaly" is first observed in FeSCs, which exhibits a scaling behavior similar to f-electron HF materials. Furthermore, the scaling rule also regulates the manifestation of magnetic fluctuation. These results undoubtedly support an emergent Kondo lattice scenario for the d-electron HF behavior, which qualifies the AFe_{2}As_{2} (A=K, Rb, Cs) as d-electron HF superconductors. PMID:27104721

  19. A Fortunate Story of an Unusual AK-47 Bullet Trajectory: Always Keep a Smartphone in Your Pocket.

    PubMed

    Thabouillot, Oscar; Perrier, Pierre; Roche, Nicolas-Charles; Agard, David; Barbier, Olivier; Martin, Guillaume; Viant, Eric; Leclere, Jean-Baptiste

    2016-06-01

    This is a report of a fortunate story of an unusual AK-47 bullet trajectory which took place during the Paris (France) attack of November 13th, 2015. A young man, trying to protect his girlfriend, interfered between her and a shooter. He had been wounded in the posterior compartment of the thigh. The bullet penetrated him and, instead of exiting, rebound against his Smartphone, which was in the front pocket of his pants. Thanks to that, the missile bullet did not injure his girlfriend but ended its trajectory in the fat tissue of his thigh. Thabouillot O , Perrier P , Roche NC , Agard D , Barbier O , Martin G , Viant E , Leclere JB . A fortunate story of an unusual AK-47 bullet trajectory: always keep a Smartphone in your pocket. Prehosp Disaster Med, 2016;31(3):343-345. PMID:27086713

  20. Performance of the high-resolution atmospheric model HRRR-AK for correcting geodetic observations from spaceborne radars

    PubMed Central

    Gong, W; Meyer, F J; Webley, P; Morton, D

    2013-01-01

    [1] Atmospheric phase delays are considered to be one of the main performance limitations for high-quality satellite radar techniques, especially when applied to ground deformation monitoring. Numerical weather prediction (NWP) models are widely seen as a promising tool for the mitigation of atmospheric delays as they can provide knowledge of the atmospheric conditions at the time of Synthetic Aperture Radar data acquisition. However, a thorough statistical analysis of the performance of using NWP production in radar signal correction is missing to date. This study provides a quantitative analysis of the accuracy in using operational NWP products for signal delay correction in satellite radar geodetic remote sensing. The study focuses on the temperate, subarctic, and Arctic climate regions due to a prevalence of relevant geophysical signals in these areas. In this study, the operational High Resolution Rapid Refresh over the Alaska region (HRRR-AK) model is used and evaluated. Five test sites were selected over Alaska (AK), USA, covering a wide range of climatic regimes that are commonly encountered in high-latitude regions. The performance of the HRRR-AK NWP model for correcting absolute atmospheric range delays of radar signals is assessed by comparing to radiosonde observations. The average estimation accuracy for the one-way zenith total atmospheric delay from 24 h simulations was calculated to be better than ∼14 mm. This suggests that the HRRR-AK operational products are a good data source for spaceborne geodetic radar observations atmospheric delay correction, if the geophysical signal to be observed is larger than 20 mm. PMID:25973360

  1. Quantitative assessment of lipiodol deposition after Chemoembolization: Comparison between cone-beam CT and multi-detector CT

    PubMed Central

    Chen, Rongxin; Geschwind, Jean-François; Wang, Zhijun; Tacher, Vania; Lin, MingDe

    2013-01-01

    Purpose To evaluate the ability of cone-beam computed tomography (CBCT) acquired directly after TACE to assess lipiodol deposition in hepatocellular carcinoma (HCC) and compare it to unenhanced MDCT. Materials and methods Fifteen HCC patients were treated with conventional TACE, and CBCT was used to assess the lipiodol deposition directly after TACE. Unenhanced MDCT was performed 24 hours after TACE. Four patients were excluded because the margin of tumor or area of lipiodol deposition was not clear. The image enhancement density of the entire tumor (T) and liver parenchyma (L) was measured by ImageJ software, and tumor-to-liver contrast (TLC) was calculated. In addition, volumetric measurement of tumor and lipiodol was performed by semiautomatic 3D volume segmentation and compared using linear regression to evaluate consistency between two imaging modalities. Results The mean value of TLC on CBCT was not significantly different from that on MDCT (337.7±233.5 HU versus 283.0±152.1 HU, P=0.103). The average volume of the whole tumor and of only the lipiodol deposited regions, and the calculated average percentage of lipiodol retention on CBCT were not significantly different when compared to MDCT (tumor volume: 9.6±11.8 cm3 versus 10.8±14.2 cm3, P=0.142; lipiodol volume: 6.3±7.7 cm3 versus 7.0±8.1 cm3, P=0.214; percentage of lipiodol retention: 68.9%±24.0% versus 72.2%±23.1%, P=0.578). Additionally, there was a high correlation in the volume of tumor and lipiodol between CBCT and MDCT (R2=0.919 and 0.903, respectively). Conclusions The quantitative image enhancement and volume analyses demonstrate that CBCT is similar to MDCT in assessing the lipiodol deposition in HCC after TACE. PMID:24094672

  2. Anchorage, AK

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Anchorage, Alaska and Cook Inlet are seen in this 30 by 30 km (19 by 19 miles) sub-image, acquired May 12, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Orbiting at an altitude of 705 km (430 miles) on board NASA's Terra satellite, ASTER provides data at a resolution of 15 m (47 feet) and allows creation of this simulated natural color image. At the center of the image is the Ted Stevens Anchorage International Airport; in the upper right corner is Elmendorf Air Force Base. Dark green coniferous forests are seen in the northwest part of the image. A golf course, with its lush green fairways, is just south of the Air Force Base.

    The image covers an area of 30 by 30 km, was acquired May 12, 2000, and is located at 61.2 degrees north latitude and 149.9 degrees west longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats, potentially active volcanoes, thermal pollution, and coral reef degradation; identifying crop stress; determining cloud morphology and physical properties; evaluating wetlands; mapping surface temperature of soils and geology; and measuring surface heat balance.

  3. Computing Life

    ERIC Educational Resources Information Center

    National Institute of General Medical Sciences (NIGMS), 2009

    2009-01-01

    Computer advances now let researchers quickly search through DNA sequences to find gene variations that could lead to disease, simulate how flu might spread through one's school, and design three-dimensional animations of molecules that rival any video game. By teaming computers and biology, scientists can answer new and old questions that could…

  4. Computational Pathology

    PubMed Central

    Louis, David N.; Feldman, Michael; Carter, Alexis B.; Dighe, Anand S.; Pfeifer, John D.; Bry, Lynn; Almeida, Jonas S.; Saltz, Joel; Braun, Jonathan; Tomaszewski, John E.; Gilbertson, John R.; Sinard, John H.; Gerber, Georg K.; Galli, Stephen J.; Golden, Jeffrey A.; Becich, Michael J.

    2016-01-01

    Context We define the scope and needs within the new discipline of computational pathology, a discipline critical to the future of both the practice of pathology and, more broadly, medical practice in general. Objective To define the scope and needs of computational pathology. Data Sources A meeting was convened in Boston, Massachusetts, in July 2014 prior to the annual Association of Pathology Chairs meeting, and it was attended by a variety of pathologists, including individuals highly invested in pathology informatics as well as chairs of pathology departments. Conclusions The meeting made recommendations to promote computational pathology, including clearly defining the field and articulating its value propositions; asserting that the value propositions for health care systems must include means to incorporate robust computational approaches to implement data-driven methods that aid in guiding individual and population health care; leveraging computational pathology as a center for data interpretation in modern health care systems; stating that realizing the value proposition will require working with institutional administrations, other departments, and pathology colleagues; declaring that a robust pipeline should be fostered that trains and develops future computational pathologists, for those with both pathology and non-pathology backgrounds; and deciding that computational pathology should serve as a hub for data-related research in health care systems. The dissemination of these recommendations to pathology and bioinformatics departments should help facilitate the development of computational pathology. PMID:26098131

  5. Computer Code

    NASA Technical Reports Server (NTRS)

    1985-01-01

    COSMIC MINIVER, a computer code developed by NASA for analyzing aerodynamic heating and heat transfer on the Space Shuttle, has been used by Marquardt Company to analyze heat transfer on Navy/Air Force missile bodies. The code analyzes heat transfer by four different methods which can be compared for accuracy. MINIVER saved Marquardt three months in computer time and $15,000.

  6. Computational astrophysics

    NASA Technical Reports Server (NTRS)

    Miller, Richard H.

    1987-01-01

    Astronomy is an area of applied physics in which unusually beautiful objects challenge the imagination to explain observed phenomena in terms of known laws of physics. It is a field that has stimulated the development of physical laws and of mathematical and computational methods. Current computational applications are discussed in terms of stellar and galactic evolution, galactic dynamics, and particle motions.

  7. Recreational Computing.

    ERIC Educational Resources Information Center

    Strot, Melody

    1999-01-01

    Urges teachers of gifted students to allow students unstructured recreational computer time in the classroom to encourage student exploration and discovery, to promote creativity, to develop problem-solving skills, and to allow time to revisit programs and complete their own tasks. Different types of educational computer programs are referenced.…

  8. Computer Insecurity.

    ERIC Educational Resources Information Center

    Wilson, David L.

    1994-01-01

    College administrators recently appealed to students and faculty to change their computer passwords after security experts announced that tens of thousands had been stolen by computer hackers. Federal officials are investigating. Such attacks are not uncommon, but the most effective solutions are either inconvenient or cumbersome. (MSE)

  9. I, Computer

    ERIC Educational Resources Information Center

    Barack, Lauren

    2005-01-01

    What child hasn't chatted with friends through a computer? But chatting with a computer? Some Danish scientists have literally put a face on their latest software program, bringing to virtual life storyteller Hans Christian Andersen, who engages users in actual conversations. The digitized Andersen resides at the Hans Christian Andersen Museum in…

  10. Computer Recreations.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1989-01-01

    Discussed are three examples of computer graphics including biomorphs, Truchet tilings, and fractal popcorn. The graphics are shown and the basic algorithm using multiple iteration of a particular function or mathematical operation is described. An illustration of a snail shell created by computer graphics is presented. (YP)

  11. Computer Graphics.

    ERIC Educational Resources Information Center

    Halpern, Jeanne W.

    1970-01-01

    Computer graphics have been called the most exciting development in computer technology. At the University of Michigan, three kinds of graphics output equipment are now being used: symbolic printers, line plotters or drafting devices, and cathode-ray tubes (CRT). Six examples are given that demonstrate the range of graphics use at the University.…

  12. Computer News

    ERIC Educational Resources Information Center

    Science Activities: Classroom Projects and Curriculum Ideas, 2007

    2007-01-01

    This article presents several news stories about computers and technology. (1) Applied Science Associates of Narragansett, Rhode Island is providing computer modeling technology to help locate the remains to the USS Bonhomme Richard, which sank in 1779 after claiming a Revolutionary War victory. (2) Whyville, the leading edu-tainment virtual world…

  13. Grid Computing

    NASA Astrophysics Data System (ADS)

    Foster, Ian

    2001-08-01

    The term "Grid Computing" refers to the use, for computational purposes, of emerging distributed Grid infrastructures: that is, network and middleware services designed to provide on-demand and high-performance access to all important computational resources within an organization or community. Grid computing promises to enable both evolutionary and revolutionary changes in the practice of computational science and engineering based on new application modalities such as high-speed distributed analysis of large datasets, collaborative engineering and visualization, desktop access to computation via "science portals," rapid parameter studies and Monte Carlo simulations that use all available resources within an organization, and online analysis of data from scientific instruments. In this article, I examine the status of Grid computing circa 2000, briefly reviewing some relevant history, outlining major current Grid research and development activities, and pointing out likely directions for future work. I also present a number of case studies, selected to illustrate the potential of Grid computing in various areas of science.

  14. s-triazine degrading bacterial isolate Arthrobacter sp. AK-YN10, a candidate for bioaugmentation of atrazine contaminated soil.

    PubMed

    Sagarkar, Sneha; Bhardwaj, Pooja; Storck, Veronika; Devers-Lamrani, Marion; Martin-Laurent, Fabrice; Kapley, Atya

    2016-01-01

    The Arthrobacter sp. strain AK-YN10 is an s-triazine pesticide degrading bacterium isolated from a sugarcane field in Central India with history of repeated atrazine use. AK-YN10 was shown to degrade 99 % of atrazine in 30 h from media supplemented with 1000 mg L(-1) of the herbicide. Draft genome sequencing revealed similarity to pAO1, TC1, and TC2 catabolic plasmids of the Arthrobacter taxon. Plasmid profiling analyses revealed the presence of four catabolic plasmids. The trzN, atzB, and atzC atrazine-degrading genes were located on a plasmid of approximately 113 kb.The flagellar operon found in the AK-YN10 draft genome suggests motility, an interesting trait for a bioremediation agent, and was homologous to that of Arthrobacter chlorophenolicus. The multiple s-triazines degradation property of this isolate makes it a good candidate for bioremediation of soils contaminated by s-triazine pesticides. PMID:26403923

  15. A founder EIF2AK4 mutation causes an aggressive form of pulmonary arterial hypertension in Iberian Gypsies.

    PubMed

    Tenorio, J; Navas, P; Barrios, E; Fernández, L; Nevado, J; Quezada, C A; López-Meseguer, M; Arias, P; Mena, R; Lobo, J L; Alvarez, C; Heath, K; Escribano-Subías, P; Lapunzina, P

    2015-12-01

    Pulmonary arterial hypertension (PAH) is a pathological condition characterized by a persistent and progressive elevation of pulmonary vascular resistance with devastating consequences if untreated. In the past recent years, several genes have been related to PAH, however, the molecular defect remains unknown in a significant proportion of patients with familial PAH (∼20%). During the past few years, we have observed that PAH shows a particular behavior in Iberian Gypsies, with more aggressive course and frequently affecting multiple members of the same family. We studied five Gypsy families in whom at least one individual from each family developed a severe form of PAH and in whom no mutation had been identified in the common genes. We applied SNP-array-based homozygosity mapping in three families and obtained, among others, one of which included the gene EIF2AK4, recently reported in patients with PAH from group-1' pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH). Subsequently, we sequenced EIF2AK4 and found a homozygous mutation in all five families: c.3344C>T(p.P1115L). The majority of our patients required early lung transplantation. Hence, this mutation appeared with a more severe phenotype than previously reported for other EIF2AK4 mutations. The finding of this novel mutation is important for genetic counseling and calculation of population recurrence risks. PMID:25512148

  16. Diagnosis of Small-Bowel Diseases: Prospective Comparison of Multi-Detector Row CT Enterography with MR Enterography.

    PubMed

    Masselli, Gabriele; Di Tola, Marco; Casciani, Emanuele; Polettini, Elisabetta; Laghi, Francesca; Monti, Riccardo; Bernieri, Maria Giulia; Gualdi, Gianfranco

    2016-05-01

    Purpose To prospectively compare the accuracies of computed tomographic (CT) enterography and magnetic resonance (MR) enterography for the detection and characterization of small-bowel diseases. Materials and Methods The institutional review board approved the study protocol, and informed consent was obtained from all participants. From June 2009 to July 2013, 150 consecutive patients (81 men and 69 women; mean age, 38.8 years; range, 18-74 years), who were suspected of having a small-bowel disease on the basis of clinical findings and whose previous upper and lower gastrointestinal endoscopy findings were normal, underwent CT and MR enterography. Two independent readers reviewed CT and MR enterographic images for the presence of small-bowel diseases, for differentiating between inflammatory and noninflammatory diseases, and for extraenteric complications. The histopathologic findings of surgical (n = 23) and endoscopic (n = 32) biopsy specimens were used as the reference standard; the results of video-capsule endoscopy (n = 36) and clinical follow-up (n = 59) were used only to confirm the absence of small-bowel disease. Results MR and CT enterography were successfully performed in all 150 patients. Overall sensitivity, specificity, and accuracy, respectively, in identifying patients with small-bowel lesions were 75.9% (41 of 54), 94.8% (91 of 96), and 88.0% (132 of 150) for CT enterography and 92.6% (50 of 54), 99.0% (95 of 96), and 96.7% (145 of 150) for MR enterography. The sensitivity of MR enterography was significantly higher than that of CT enterography for the detection of both overall small-bowel diseases (P = .0159) and neoplastic diseases (P = .0412) but not for the detection of inflammatory diseases (P > .99) or noninflammatory and nonneoplastic diseases (P = .6171). Conclusion MR enterography is more accurate than CT enterography in the detection of small-bowel diseases; MR enterography was more accurate in detecting neoplastic diseases in particular

  17. Multidetector CT with 3-dimensional volume rendering in the evaluation of the spine in patients with Neurofibromatosis type 1: a retrospective review in 73 patients

    PubMed Central

    2014-01-01

    Introduction Neurofibromatosis type 1 (NF-1) may involve the spine as various abnormalities including bony dysplasia, scoliosis, and nerve sheath tumors. Surgery may be performed for stabilization of the spine. We have seen an increase in requests for multidetector CT (MDCT) imaging with the (three-dimensional) 3D-volume rendered (VR) images in patients evaluated at our institution. We, therefore, investigated how MDCT could be best utilized in this patient population. Methods Seventy-three patients with NF-1 were identified in whom MDCT imaging was performed for diagnostic, pre-operative, or post-operative evaluation of spinal abnormalities. True axial source images and two dimensional (2D) orthogonal reconstructed MDCT images, as well as the VR images, were compared with plain radiographs and MRI. In addition, the MDCT study was compared to the VR images. These studies were reviewed to compare assessment of A) bony abnormalities such as remodeling from dural ectasia, dysplasia, and fusion, B) abnormal spinal curvature, C) nerve sheath tumors, and D) surgical instrumentation. Results When compared to plain radiographs, the MDCT and VR images were rated as helpful for evaluating the abnormalities of the spine in 19 of 24 patients for a total of 30 findings. This included the following categories A) (n = 6), B) (n = 5), C) (n = 7), and D) (n = 12). Compared to MR, the MDCT and VR study was helpful in evaluating the findings of NF-1 in 24 of 36 patients for a total of 40 findings. This included the following categories A) (n = 12), B) (n = 10), C) (n = 3), and D) (n = 15). When the VR images were compared to the orthogonal MDCT, the VR images was rated as helpful in 41 of 73 patients for a total of 60 findings, including the following categories: A) (n = 11), B) (n = 24), C) (n = 0), and D) (n = 25). Conclusion MDCT has distinct advantages over plain radiographs and MR imaging, and the VR images over MDCT in the

  18. Optical computing.

    NASA Technical Reports Server (NTRS)

    Stroke, G. W.

    1972-01-01

    Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.

  19. RH-TRU Waste Inventory Characterization by AK and Proposed WIPP RH-TRU Waste Characterization Objectives

    SciTech Connect

    Most, W. A.; Kehrman, R.; Gist, C.; Biedscheid, J.; Devarakonda, J.; Whitworth, J.

    2002-02-26

    The U.S. Department of Energy (DOE)-Carlsbad Field Office (CBFO) has developed draft documentation to present the proposed Waste Isolation Pilot Plant (WIPP) remote-handled (RH-) transuranic (TRU) waste characterization program to its regulators, the U.S. Environmental Protection Agency and the New Mexico Environment Department. Compliance with Title 40, Code of Federal Regulations, Parts 191 and 194; the WIPP Land Withdrawal Act (PL 102-579); and the WIPP Hazardous Waste Facility Permit, as well as the Certificates of Compliance for the 72-B and 10-160B Casks, requires that specific waste parameter limits be imposed on DOE sites disposing of TRU waste at WIPP. The DOE-CBFO must control the sites' compliance with the limits by specifying allowable characterization methods. As with the established WIPP contact handled TRU waste characterization program, the DOE-CBFO has proposed a Remote-Handled TRU Waste Acceptance Criteria (RH-WAC) document consolidating the requirements from various regulatory drivers and proposed allowable characterization methods. These criteria are consistent with the recommendation of a recent National Academy Sciences/National Research Council to develop an RH-TRU waste characterization approach that removes current self imposed requirements that lack a legal or safety basis. As proposed in the draft RH-WAC and other preliminary documents, the DOE-CBFO RH-TRU waste characterization program proposes the use of acceptable knowledge (AK) as the primary method for obtaining required characterization information. The use of AK involves applying knowledge of the waste in light of the materials or processes used to generate the waste. Documentation, records, or processes providing information about various attributes of a waste stream, such as chemical, physical, and radiological properties, may be used as AK and may be applied to individual waste containers either independently or in conjunction with radiography, visual examination, assay, and

  20. Evolutionary Computing

    SciTech Connect

    Patton, Robert M; Cui, Xiaohui; Jiao, Yu; Potok, Thomas E

    2008-01-01

    The rate at which information overwhelms humans is significantly more than the rate at which humans have learned to process, analyze, and leverage this information. To overcome this challenge, new methods of computing must be formulated, and scientist and engineers have looked to nature for inspiration in developing these new methods. Consequently, evolutionary computing has emerged as new paradigm for computing, and has rapidly demonstrated its ability to solve real-world problems where traditional techniques have failed. This field of work has now become quite broad and encompasses areas ranging from artificial life to neural networks. This chapter focuses specifically on two sub-areas of nature-inspired computing: Evolutionary Algorithms and Swarm Intelligence.

  1. Computer Stimulation

    ERIC Educational Resources Information Center

    Moore, John W.; Moore, Elizabeth

    1977-01-01

    Discusses computer simulation approach of Limits to Growth, in which interactions of five variables (population, pollution, resources, food per capita, and industrial output per capita) indicate status of the world. Reviews other books that predict future of the world. (CS)

  2. LHC Computing

    SciTech Connect

    Lincoln, Don

    2015-07-28

    The LHC is the world’s highest energy particle accelerator and scientists use it to record an unprecedented amount of data. This data is recorded in electronic format and it requires an enormous computational infrastructure to convert the raw data into conclusions about the fundamental rules that govern matter. In this video, Fermilab’s Dr. Don Lincoln gives us a sense of just how much data is involved and the incredible computer resources that makes it all possible.

  3. Advanced computing

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Advanced concepts in hardware, software and algorithms are being pursued for application in next generation space computers and for ground based analysis of space data. The research program focuses on massively parallel computation and neural networks, as well as optical processing and optical networking which are discussed under photonics. Also included are theoretical programs in neural and nonlinear science, and device development for magnetic and ferroelectric memories.

  4. Long noncoding RNA AK056155 involved in the development of Loeys-Dietz syndrome through AKT/PI3K signaling pathway

    PubMed Central

    Yu, Bo; Liu, Long; Sun, Huan; Chen, Yu

    2015-01-01

    Loeys-Dietz syndrome (LDS) is an autosomal dominant genetic connective tissue disorder, and most of LDS patients will develop into aortic aneurysm. Unfortunately, there is no known cure, and a high risk of death from aortic aneurysm rupture. However the detailed mechanism is still unknown. In order to explore the mechanism, we firstly used bioinformatics to predict, and then verified with biology methods. Firstly, we found that LncRNA AK056155 was differentially expressed in peripheral blood circulating endothelial cells between normal patients and LDS patients by bioinformatics. Then we further verified that AK056155 was also overexpressed in aortic aneurysm patients by RT-PCR. Moreover, we demonstrated that the expression of AK056155 can be enhanced by TGF-β1 in a concentration or time depended manner in HUVECs by RT-PCR. Furthermore, the expression of AK056155 was reduced with treatment of PI3K inhibitor (LY294002) or AKT inhibitor (GDC-0068) in combination with TGF-β1. These results indicate that AK056155 involved in the development of Loeys-Dietz syndrome through AKT/PI3K signaling pathway, it may provide a promising target gene to prevent LDS develop in to aortic aneurysm. PMID:26617788

  5. Chromatin Computation

    PubMed Central

    Bryant, Barbara

    2012-01-01

    In living cells, DNA is packaged along with protein and RNA into chromatin. Chemical modifications to nucleotides and histone proteins are added, removed and recognized by multi-functional molecular complexes. Here I define a new computational model, in which chromatin modifications are information units that can be written onto a one-dimensional string of nucleosomes, analogous to the symbols written onto cells of a Turing machine tape, and chromatin-modifying complexes are modeled as read-write rules that operate on a finite set of adjacent nucleosomes. I illustrate the use of this “chromatin computer” to solve an instance of the Hamiltonian path problem. I prove that chromatin computers are computationally universal – and therefore more powerful than the logic circuits often used to model transcription factor control of gene expression. Features of biological chromatin provide a rich instruction set for efficient computation of nontrivial algorithms in biological time scales. Modeling chromatin as a computer shifts how we think about chromatin function, suggests new approaches to medical intervention, and lays the groundwork for the engineering of a new class of biological computing machines. PMID:22567109

  6. Computational chemistry

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  7. Computational structures for robotic computations

    NASA Technical Reports Server (NTRS)

    Lee, C. S. G.; Chang, P. R.

    1987-01-01

    The computational problem of inverse kinematics and inverse dynamics of robot manipulators by taking advantage of parallelism and pipelining architectures is discussed. For the computation of inverse kinematic position solution, a maximum pipelined CORDIC architecture has been designed based on a functional decomposition of the closed-form joint equations. For the inverse dynamics computation, an efficient p-fold parallel algorithm to overcome the recurrence problem of the Newton-Euler equations of motion to achieve the time lower bound of O(log sub 2 n) has also been developed.

  8. Uncinate Process Variations and Their Relationship with Ostiomeatal Complex: A Pictorial Essay of Multidedector Computed Tomography (MDCT) Findings.

    PubMed

    Güngör, Gülay; Okur, Nazan; Okur, Erdoğan

    2016-01-01

    The ostiomeatal complex (OMC) is a key area for the drainage and ventilation of the paranasal sinuses. Stenosis created by inflammation and anatomic variations in this region causes an ideal ground for parasanal sinus infections, by preventing the drainage and ventilation of the sinuses. In today's diagnostics of paranasal sinus infections, the role of evaluation of OMC anatomical variations and soft tissue pathology has increased.. Knowing the anatomical details is important in terms of directing both medical and surgical treatment. The uncinate process (UP) constitutes the most important structure of the ostiomeatal complex, playing a role in mucociliary activity. UP variations can cause mucociliary drainage and ventilation problems, causing complications during surgery. Therefore, knowing and identifying their appearances in multidetector computed tomography (MDCT), the most frequently used radiological imaging method for these variations, becomes a very important consideration. PMID:27158282

  9. Uncinate Process Variations and Their Relationship with Ostiomeatal Complex: A Pictorial Essay of Multidedector Computed Tomography (MDCT) Findings

    PubMed Central

    Güngör, Gülay; Okur, Nazan; Okur, Erdoğan

    2016-01-01

    Summary The ostiomeatal complex (OMC) is a key area for the drainage and ventilation of the paranasal sinuses. Stenosis created by inflammation and anatomic variations in this region causes an ideal ground for parasanal sinus infections, by preventing the drainage and ventilation of the sinuses. In today’s diagnostics of paranasal sinus infections, the role of evaluation of OMC anatomical variations and soft tissue pathology has increased.. Knowing the anatomical details is important in terms of directing both medical and surgical treatment. The uncinate process (UP) constitutes the most important structure of the ostiomeatal complex, playing a role in mucociliary activity. UP variations can cause mucociliary drainage and ventilation problems, causing complications during surgery. Therefore, knowing and identifying their appearances in multidetector computed tomography (MDCT), the most frequently used radiological imaging method for these variations, becomes a very important consideration. PMID:27158282

  10. Sampling The Radon Transformation In Conventional Computed Tomography

    NASA Astrophysics Data System (ADS)

    Parker, Dennis L.; Smith, Vernon; Peschmann, Kristian R.; Couch, John L.

    1981-07-01

    The sampling geometry for conventional, multidetector, computed tomography is illustrated in terms of the Radon transformation for both rotate-rotate (3rd generation fan beam) and rotate-stationary (4th generation fan beam) scanners. By deriving an expression for the outline of the sampling region in the Radon transformation for each detector measurement it is demonstrated that the entire Radon transformation can be covered by non-overlapping sampling regions with the assumption of negligible detector dead space. An expression for angular aliasing is derived which demonstrates that object dependent artifacts can occur if the angular width of the sampling regions in conjunction with the angular sampling increment does not provide sufficient suppression of the high order angular harmonics in the representation of the scanned object. The number of views necessary to suppress angular aliasing, as well as the potential spatial resolution and general image quality are shown to be fundamentally related to the size, shape, and relative orientation of the Radon transformation sampling regions.

  11. Computed tomography studies of lung ventilation and perfusion.

    PubMed

    Hoffman, Eric A; Chon, Deokiee

    2005-01-01

    With the emergence of multidetector-row computed tomography (CT) it is now possible to image both structure and function via use of a single imaging modality. Breath-hold spiral CT provides detail of the airway and vascular trees along with texture reflective of the state of the lung parenchyma. Use of stable xenon gas wash-in and/or wash-out methods using an axial mode of the CT scanner whereby images are acquired through gating to the respiratory cycle provide detailed images of regional ventilation with isotropic voxel dimensions now on the order of 0.4 mm. Axial scanning during a breath hold and gating to the electrocardiogram during the passage of a sharp bolus injection of iodinated contrast agent provide detailed images of regional pulmonary perfusion. These dynamic CT methods for the study of regional lung function are discussed in the context of other methods that have been used to study heterogeneity of lung function. PMID:16352755

  12. [DNA computing].

    PubMed

    Błasiak, Janusz; Krasiński, Tadeusz; Popławski, Tomasz; Sakowski, Sebastian

    2011-01-01

    Biocomputers can be an alternative for traditional "silicon-based" computers, which continuous development may be limited due to further miniaturization (imposed by the Heisenberg Uncertainty Principle) and increasing the amount of information between the central processing unit and the main memory (von Neuman bottleneck). The idea of DNA computing came true for the first time in 1994, when Adleman solved the Hamiltonian Path Problem using short DNA oligomers and DNA ligase. In the early 2000s a series of biocomputer models was presented with a seminal work of Shapiro and his colleguas who presented molecular 2 state finite automaton, in which the restriction enzyme, FokI, constituted hardware and short DNA oligomers were software as well as input/output signals. DNA molecules provided also energy for this machine. DNA computing can be exploited in many applications, from study on the gene expression pattern to diagnosis and therapy of cancer. The idea of DNA computing is still in progress in research both in vitro and in vivo and at least promising results of these research allow to have a hope for a breakthrough in the computer science. PMID:21735816

  13. Computational mechanics

    SciTech Connect

    Goudreau, G.L.

    1993-03-01

    The Computational Mechanics thrust area sponsors research into the underlying solid, structural and fluid mechanics and heat transfer necessary for the development of state-of-the-art general purpose computational software. The scale of computational capability spans office workstations, departmental computer servers, and Cray-class supercomputers. The DYNA, NIKE, and TOPAZ codes have achieved world fame through our broad collaborators program, in addition to their strong support of on-going Lawrence Livermore National Laboratory (LLNL) programs. Several technology transfer initiatives have been based on these established codes, teaming LLNL analysts and researchers with counterparts in industry, extending code capability to specific industrial interests of casting, metalforming, and automobile crash dynamics. The next-generation solid/structural mechanics code, ParaDyn, is targeted toward massively parallel computers, which will extend performance from gigaflop to teraflop power. Our work for FY-92 is described in the following eight articles: (1) Solution Strategies: New Approaches for Strongly Nonlinear Quasistatic Problems Using DYNA3D; (2) Enhanced Enforcement of Mechanical Contact: The Method of Augmented Lagrangians; (3) ParaDyn: New Generation Solid/Structural Mechanics Codes for Massively Parallel Processors; (4) Composite Damage Modeling; (5) HYDRA: A Parallel/Vector Flow Solver for Three-Dimensional, Transient, Incompressible Viscous How; (6) Development and Testing of the TRIM3D Radiation Heat Transfer Code; (7) A Methodology for Calculating the Seismic Response of Critical Structures; and (8) Reinforced Concrete Damage Modeling.

  14. The Metabolic Pathway of 4-Aminophenol in Burkholderia sp. Strain AK-5 Differs from That of Aniline and Aniline with C-4 Substituents

    PubMed Central

    Takenaka, Shinji; Okugawa, Susumu; Kadowaki, Maho; Murakami, Shuichiro; Aoki, Kenji

    2003-01-01

    Burkholderia sp. strain AK-5 utilized 4-aminophenol as the sole carbon, nitrogen, and energy source. A pathway for the metabolism of 4-aminophenol in strain AK-5 was proposed based on the identification of three key metabolites by gas chromatography-mass spectrometry analysis. Strain AK-5 converted 4-aminophenol to 1,2,4-trihydroxybenzene via 1,4-benzenediol. 1,2,4-Trihydroxybenzene 1,2-dioxygenase cleaved the benzene ring of 1,2,4-trihydroxybenzene to form maleylacetic acid. The enzyme showed a high dioxygenase activity only for 1,2,4-trihydroxybenzene, with Km and Vmax values of 9.6 μM and 6.8 μmol min−1 mg of protein−1, respectively. PMID:12957929

  15. Protoplanetary Disk Shadowing by Gas Infalling onto the Young Star AK Sco

    NASA Astrophysics Data System (ADS)

    Gómez de Castro, Ana I.; Loyd, Robert O. P.; France, Kevin; Sytov, Alexey; Bisikalo, Dmitry

    2016-02-01

    Young solar-type stars grow through the accretion of material from the circumstellar disk during pre-main-sequence (PMS) evolution. The ultraviolet radiation generated in this process plays a key role in the chemistry and evolution of young planetary disks. In particular, the hydrogen Lyα line (Lyα) etches the disk surface by driving photoevaporative flows that control disk evolution. Using the Hubble Space Telescope, we have monitored the PMS binary star AK Sco during the periastron passage and have detected a drop of the H2 flux by up to 10% lasting 5.9 hr. We show that the decrease of the H2 flux can be produced by the occultation of the stellar Lyα photons by a gas stream in free fall from 3 R{}*. Given the high optical depth of the Lyα line, a very low gas column of {N}{{H}}\\gt 5× {10}17 cm‑2 suffices to block the Lyα radiation without producing noticeable effects in the rest of the stellar spectral tracers.

  16. Computational psychiatry.

    PubMed

    Wang, Xiao-Jing; Krystal, John H

    2014-11-01

    Psychiatric disorders such as autism and schizophrenia, arise from abnormalities in brain systems that underlie cognitive, emotional, and social functions. The brain is enormously complex and its abundant feedback loops on multiple scales preclude intuitive explication of circuit functions. In close interplay with experiments, theory and computational modeling are essential for understanding how, precisely, neural circuits generate flexible behaviors and their impairments give rise to psychiatric symptoms. This Perspective highlights recent progress in applying computational neuroscience to the study of mental disorders. We outline basic approaches, including identification of core deficits that cut across disease categories, biologically realistic modeling bridging cellular and synaptic mechanisms with behavior, and model-aided diagnosis. The need for new research strategies in psychiatry is urgent. Computational psychiatry potentially provides powerful tools for elucidating pathophysiology that may inform both diagnosis and treatment. To achieve this promise will require investment in cross-disciplinary training and research in this nascent field. PMID:25442941

  17. Computational Psychiatry

    PubMed Central

    Wang, Xiao-Jing; Krystal, John H.

    2014-01-01

    Psychiatric disorders such as autism and schizophrenia arise from abnormalities in brain systems that underlie cognitive, emotional and social functions. The brain is enormously complex and its abundant feedback loops on multiple scales preclude intuitive explication of circuit functions. In close interplay with experiments, theory and computational modeling are essential for understanding how, precisely, neural circuits generate flexible behaviors and their impairments give rise to psychiatric symptoms. This Perspective highlights recent progress in applying computational neuroscience to the study of mental disorders. We outline basic approaches, including identification of core deficits that cut across disease categories, biologically-realistic modeling bridging cellular and synaptic mechanisms with behavior, model-aided diagnosis. The need for new research strategies in psychiatry is urgent. Computational psychiatry potentially provides powerful tools for elucidating pathophysiology that may inform both diagnosis and treatment. To achieve this promise will require investment in cross-disciplinary training and research in this nascent field. PMID:25442941

  18. Computational mechanics

    SciTech Connect

    Raboin, P J

    1998-01-01

    The Computational Mechanics thrust area is a vital and growing facet of the Mechanical Engineering Department at Lawrence Livermore National Laboratory (LLNL). This work supports the development of computational analysis tools in the areas of structural mechanics and heat transfer. Over 75 analysts depend on thrust area-supported software running on a variety of computing platforms to meet the demands of LLNL programs. Interactions with the Department of Defense (DOD) High Performance Computing and Modernization Program and the Defense Special Weapons Agency are of special importance as they support our ParaDyn project in its development of new parallel capabilities for DYNA3D. Working with DOD customers has been invaluable to driving this technology in directions mutually beneficial to the Department of Energy. Other projects associated with the Computational Mechanics thrust area include work with the Partnership for a New Generation Vehicle (PNGV) for ''Springback Predictability'' and with the Federal Aviation Administration (FAA) for the ''Development of Methodologies for Evaluating Containment and Mitigation of Uncontained Engine Debris.'' In this report for FY-97, there are five articles detailing three code development activities and two projects that synthesized new code capabilities with new analytic research in damage/failure and biomechanics. The article this year are: (1) Energy- and Momentum-Conserving Rigid-Body Contact for NIKE3D and DYNA3D; (2) Computational Modeling of Prosthetics: A New Approach to Implant Design; (3) Characterization of Laser-Induced Mechanical Failure Damage of Optical Components; (4) Parallel Algorithm Research for Solid Mechanics Applications Using Finite Element Analysis; and (5) An Accurate One-Step Elasto-Plasticity Algorithm for Shell Elements in DYNA3D.

  19. Computational vision

    NASA Technical Reports Server (NTRS)

    Barrow, H. G.; Tenenbaum, J. M.

    1981-01-01

    The range of fundamental computational principles underlying human vision that equally apply to artificial and natural systems is surveyed. There emerges from research a view of the structuring of vision systems as a sequence of levels of representation, with the initial levels being primarily iconic (edges, regions, gradients) and the highest symbolic (surfaces, objects, scenes). Intermediate levels are constrained by information made available by preceding levels and information required by subsequent levels. In particular, it appears that physical and three-dimensional surface characteristics provide a critical transition from iconic to symbolic representations. A plausible vision system design incorporating these principles is outlined, and its key computational processes are elaborated.

  20. Computer viruses

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    The worm, Trojan horse, bacterium, and virus are destructive programs that attack information stored in a computer's memory. Virus programs, which propagate by incorporating copies of themselves into other programs, are a growing menace in the late-1980s world of unprotected, networked workstations and personal computers. Limited immunity is offered by memory protection hardware, digitally authenticated object programs,and antibody programs that kill specific viruses. Additional immunity can be gained from the practice of digital hygiene, primarily the refusal to use software from untrusted sources. Full immunity requires attention in a social dimension, the accountability of programmers.

  1. Computer systems

    NASA Technical Reports Server (NTRS)

    Olsen, Lola

    1992-01-01

    In addition to the discussions, Ocean Climate Data Workshop hosts gave participants an opportunity to hear about, see, and test for themselves some of the latest computer tools now available for those studying climate change and the oceans. Six speakers described computer systems and their functions. The introductory talks were followed by demonstrations to small groups of participants and some opportunities for participants to get hands-on experience. After this familiarization period, attendees were invited to return during the course of the Workshop and have one-on-one discussions and further hands-on experience with these systems. Brief summaries or abstracts of introductory presentations are addressed.

  2. Quantum Computation

    NASA Astrophysics Data System (ADS)

    Ekert, Artur

    1994-08-01

    As computers become faster they must become smaller because of the finiteness of the speed of light. The history of computer technology has involved a sequence of changes from one type of physical realisation to another - from gears to relays to valves to transistors to integrated circuits and so on. Quantum mechanics is already important in the design of microelectronic components. Soon it will be necessary to harness quantum mechanics rather than simply take it into account, and at that point it will be possible to give data processing devices new functionality.

  3. Long noncoding RNA AK126698 inhibits proliferation and migration of non-small cell lung cancer cells by targeting Frizzled-8 and suppressing Wnt/β-catenin signaling pathway

    PubMed Central

    Fu, Xiao; Li, Hui; Liu, Chunxiao; Hu, Bin; Li, Tong; Wang, Yang

    2016-01-01

    Background Recent studies indicate that long noncoding RNAs (lncRNAs) play a key role in the control of cellular processes such as proliferation, metastasis, and differentiation. The lncRNA dysregulation has been identified in all types of cancer. We previously found that lncRNA AK126698 suppresses cisplatin resistance in A549 cells through the Wnt/β-catenin signaling pathway. However, the clinical significance of lncRNA AK126698 and the molecular mechanisms through which it regulates cancer cell proliferation and migration are largely unknown. Methods We examined the expression of lncRNA AK126698 in 56 non-small cell lung cancer (NSCLC) tissue samples and three NSCLC cell lines using quantitative real-time polymerase chain reaction. Gain and loss of function approaches were used to evaluate the biological function of AK126698 in NSCLC cells. The effects of lncRNA AK126698 on cell proliferation were investigated using cell counting kit-8 and 5-ethynyl-2′-deoxyuridine assays, and apoptosis was measured by flow cytometry. Protein levels of AK126698 targets were evaluated by Western blotting. Results Our results showed that lncRNA AK126698 was significantly downregulated in NSCLC tissues, compared with paired adjacent nontumor tissue samples. Furthermore, lower AK126698 expression was associated with larger tumor size and advanced tumor stage. Ectopic AK126698 expression inhibited cell proliferation and migration and induced apoptosis. Conversely, decreased AK126698 expression promoted cell proliferation and migration and inhibited cell apoptosis. Importantly, we demonstrated that Frizzled-8, a receptor of Wnt/β-catenin pathway, was a target of AK126698. Furthermore, AK126698 could inhibit the activation of Wnt/β-catenin pathway, which was demonstrated by measuring the expression levels of Axin1, β-catenin, c-myc, cyclin D1, and E-cadherin. Conclusion It was found in the study that lncRNA AK126698 inhibits the proliferation and migration of NSCLC cells by

  4. Computer Guerrillas.

    ERIC Educational Resources Information Center

    Immel, A. Richard

    1983-01-01

    Describes several cases in which microcomputers were used to prevent large organizations (e.g., utility companies, U.S. Government Forestry Commission) from carrying out actions considered not to be in the public's best interests. The use of the computers by social activitists in their efforts to halt environmental destruction is discussed. (EAO)

  5. Computer Corner.

    ERIC Educational Resources Information Center

    Smith, David A.; And Others

    1986-01-01

    APL was invented specifically as a mathematical teaching tool, and is an excellent vehicle for teaching mathematical concepts using computers. This article illustrates the use of APL in teaching many different topics in mathematics, including logic, set theory, functions, statistics, linear algebra, and matrices. (MNS)

  6. Computer Corner.

    ERIC Educational Resources Information Center

    Mason, Margie

    1985-01-01

    Provides tips to help primary-aged students with computer keyboarding skills (suggesting the use of color codes and listing currently available software). Also describes (and lists) a program which helps test students' understanding of IF-THEN statements and illustrates some hazards of "spaghetti programming" (debugging). (JN)

  7. Computational Musicology.

    ERIC Educational Resources Information Center

    Bel, Bernard; Vecchione, Bernard

    1993-01-01

    Asserts that a revolution has been occurring in musicology since the 1970s. Contends that music has change from being only a source of emotion to appearing more open to science and techniques based on computer technology. Describes recent research and other writings about the topic and provides an extensive bibliography. (CFR)

  8. Computational trigonometry

    SciTech Connect

    Gustafson, K.

    1994-12-31

    By means of the author`s earlier theory of antieigenvalues and antieigenvectors, a new computational approach to iterative methods is presented. This enables an explicit trigonometric understanding of iterative convergence and provides new insights into the sharpness of error bounds. Direct applications to Gradient descent, Conjugate gradient, GCR(k), Orthomin, CGN, GMRES, CGS, and other matrix iterative schemes will be given.

  9. Computer proposals

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    To expand the research community's access to supercomputers, the National Science Foundation (NSF) has begun a program to match researchers who require the capabilities of a supercomputer with those facilities that have such computer resources available.Recent studies on computer needs in scientific and engineering research underscore the need for greater access to supercomputers (Eos, July 6, 1982, p. 562), especially those categorized as “Class VI” machines. Complex computer models for research on astronomy, the oceans, and the atmosphere often require such capabilities. In addition, similar needs are emerging in the earth sciences: A Union session at the AGU Fall Meeting in San Francisco this week will focus on the research computing needs of the geosciences. A Class VI supercomputer has a memory capacity of at least 1 megaword, a speed of upwards of 100 MFLOPS (million floating point operations per second), and both scalar and vector registers in the CPU (central processing unit). Examples of Class VI machines are the CRAY-1 and the CYBER 205. The high costs o f these machines, the most powerful ones available, preclude most research facilities from owning one.

  10. Interaction of cCMP with the cGK, cAK and MAPK Kinases in Murine Tissues

    PubMed Central

    Wolfertstetter, Stefanie; Reinders, Jörg; Schwede, Frank; Ruth, Peter; Schinner, Elisabeth; Schlossmann, Jens

    2015-01-01

    cAMP and cGMP are well established second messengers that are essential for numerous (patho)physiological processes. These purine cyclic nucleotides activate cAK and cGK, respectively. Recently, the existence of cCMP was described, and a possible function for this cyclic nucleotide was investigated. It was postulated that cCMP plays a role as a second messenger. However, the functions regulated by cCMP are mostly unknown. To elucidate probable functions, cCMP-binding and -activated proteins were identified using different methods. We investigated the effect of cCMP on purified cyclic nucleotide-dependent protein kinases and lung and jejunum tissues of wild type (WT), cGKI-knockout (cGKI KO) and cGKII-knockout (cGKII KO) mice. The catalytic activity of protein kinases was measured by a (γ-32P) ATP kinase assay. Cyclic nucleotide-dependent protein kinases (cAK, cGKI and cGKII) in WT tissue lysates were stimulated by cCMP. In contrast, there was no stimulation of phosphorylation in KO tissue lysates. Competitive binding assays identified cAK, cGKI, and cGKII as cCMP-binding proteins. An interaction between cCMP/MAPK and a protein-protein complex of MAPK/cGK were detected via cCMP affinity chromatography and co-immunoprecipitation, respectively. These complexes were abolished or reduced in jejunum tissues from cGKI KO or cGKII KO mice. In contrast, these complexes were observed in the lung tissues from WT, cGKI KO and cGKII KO mice. Moreover, cCMP was also able to stimulate the phosphorylation of MAPK. These results suggest that MAPK signaling is regulated by cGMP-dependent protein kinases upon activation by cCMP. Based on these results, we propose that additional cCMP-dependent protein kinases that are capable of modulating MAPK signaling could exist. Hence, cCMP could potentially act as a second messenger in the cAK/cGK and MAPK signaling pathways and play an important role in physiological processes of the jejunum and lung. PMID:25978317

  11. Strain-Driven Approach to Quantum Criticality in AFe_{2}As_{2} with A=K, Rb, and Cs.

    PubMed

    Eilers, Felix; Grube, Kai; Zocco, Diego A; Wolf, Thomas; Merz, Michael; Schweiss, Peter; Heid, Rolf; Eder, Robert; Yu, Rong; Zhu, Jian-Xin; Si, Qimiao; Shibauchi, Takasada; Löhneysen, Hilbert V

    2016-06-10

    The iron-based superconductors AFe_{2}As_{2} with A=K, Rb, Cs exhibit large Sommerfeld coefficients approaching those of heavy-fermion systems. We have investigated the magnetostriction and thermal expansion of this series to shed light on this unusual behavior. Quantum oscillations of the magnetostriction allow identifying the band-specific quasiparticle masses which by far exceed the band-structure derived masses. The divergence of the Grüneisen ratio derived from thermal expansion indicates that with increasing volume along the series a quantum critical point is approached. The critical fluctuations responsible for the enhancement of the quasiparticle masses appear to weaken the superconducting state. PMID:27341252

  12. Amorphous Computing

    NASA Astrophysics Data System (ADS)

    Sussman, Gerald

    2002-03-01

    Digital computers have always been constructed to behave as precise arrangements of reliable parts, and our techniques for organizing computations depend upon this precision and reliability. Two emerging technologies, however, are begnning to undercut these assumptions about constructing and programming computers. These technologies -- microfabrication and bioengineering -- will make it possible to assemble systems composed of myriad information- processing units at almost no cost, provided: 1) that not all the units need to work correctly; and 2) that there is no need to manufacture precise geometrical arrangements or interconnection patterns among them. Microelectronic mechanical components are becoming so inexpensive to manufacture that we can anticipate combining logic circuits, microsensors, actuators, and communications devices integrated on the same chip to produce particles that could be mixed with bulk materials, such as paints, gels, and concrete. Imagine coating bridges or buildings with smart paint that can sense and report on traffic and wind loads and monitor structural integrity of the bridge. A smart paint coating on a wall could sense vibrations, monitor the premises for intruders, or cancel noise. Even more striking, there has been such astounding progress in understanding the biochemical mechanisms in individual cells, that it appears we'll be able to harness these mechanisms to construct digital- logic circuits. Imagine a discipline of cellular engineering that could tailor-make biological cells that function as sensors and actuators, as programmable delivery vehicles for pharmaceuticals, as chemical factories for the assembly of nanoscale structures. Fabricating such systems seem to be within our reach, even if it is not yet within our grasp Fabrication, however, is only part of the story. We can envision producing vast quantities of individual computing elements, whether microfabricated particles, engineered cells, or macromolecular computing

  13. Computational method for analysis of polyethylene biodegradation

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaji; Kawai, Fusako; Shibata, Masaru; Yokoyama, Shigeo; Sudate, Yasuhiro

    2003-12-01

    In a previous study concerning the biodegradation of polyethylene, we proposed a mathematical model based on two primary factors: the direct consumption or absorption of small molecules and the successive weight loss of large molecules due to β-oxidation. Our model is an initial value problem consisting of a differential equation whose independent variable is time. Its unknown variable represents the total weight of all the polyethylene molecules that belong to a molecular-weight class specified by a parameter. In this paper, we describe a numerical technique to introduce experimental results into analysis of our model. We first establish its mathematical foundation in order to guarantee its validity, by showing that the initial value problem associated with the differential equation has a unique solution. Our computational technique is based on a linear system of differential equations derived from the original problem. We introduce some numerical results to illustrate our technique as a practical application of the linear approximation. In particular, we show how to solve the inverse problem to determine the consumption rate and the β-oxidation rate numerically, and illustrate our numerical technique by analyzing the GPC patterns of polyethylene wax obtained before and after 5 weeks cultivation of a fungus, Aspergillus sp. AK-3. A numerical simulation based on these degradation rates confirms that the primary factors of the polyethylene biodegradation posed in modeling are indeed appropriate.

  14. Bacteria as computers making computers

    PubMed Central

    Danchin, Antoine

    2009-01-01

    Various efforts to integrate biological knowledge into networks of interactions have produced a lively microbial systems biology. Putting molecular biology and computer sciences in perspective, we review another trend in systems biology, in which recursivity and information replace the usual concepts of differential equations, feedback and feedforward loops and the like. Noting that the processes of gene expression separate the genome from the cell machinery, we analyse the role of the separation between machine and program in computers. However, computers do not make computers. For cells to make cells requires a specific organization of the genetic program, which we investigate using available knowledge. Microbial genomes are organized into a paleome (the name emphasizes the role of the corresponding functions from the time of the origin of life), comprising a constructor and a replicator, and a cenome (emphasizing community-relevant genes), made up of genes that permit life in a particular context. The cell duplication process supposes rejuvenation of the machine and replication of the program. The paleome also possesses genes that enable information to accumulate in a ratchet-like process down the generations. The systems biology must include the dynamics of information creation in its future developments. PMID:19016882

  15. RATIO COMPUTER

    DOEpatents

    Post, R.F.

    1958-11-11

    An electronic computer circuit is described for producing an output voltage proportional to the product or quotient of tbe voltages of a pair of input signals. ln essence, the disclosed invention provides a computer having two channels adapted to receive separate input signals and each having amplifiers with like fixed amplification factors and like negatlve feedback amplifiers. One of the channels receives a constant signal for comparison purposes, whereby a difference signal is produced to control the amplification factors of the variable feedback amplifiers. The output of the other channel is thereby proportional to the product or quotient of input signals depending upon the relation of input to fixed signals in the first mentioned channel.

  16. Computational Combustion

    SciTech Connect

    Westbrook, C K; Mizobuchi, Y; Poinsot, T J; Smith, P J; Warnatz, J

    2004-08-26

    Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surface and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.

  17. Singularity computations

    NASA Technical Reports Server (NTRS)

    Swedlow, J. L.

    1976-01-01

    An approach is described for singularity computations based on a numerical method for elastoplastic flow to delineate radial and angular distribution of field quantities and measure the intensity of the singularity. The method is applicable to problems in solid mechanics and lends itself to certain types of heat flow and fluid motion studies. Its use is not limited to linear, elastic, small strain, or two-dimensional situations.

  18. Barrow Ak: A Focal Point for Ice-Albedo-Transmission Feedback Processes in Arctic Sea Ice.

    NASA Astrophysics Data System (ADS)

    Grenfell, T. C.; Perovich, D. K.; Eicken, H.

    2003-12-01

    represents a serious oversimplification that will significantly limit the predictive power of regional and large scale climate and dynamics models. An approach to dealing with this problem is to carry out surface-based observations of the processes involved to determine the detailed spatial and temporal variability associated with the various surface types and develop appropriate models to apply this information on larger scales. We argue that Barrow AK is critically situated for studies of the processes described above. We will present supporting results from a three-year observational sequence of heat and mass balance of the ice cover in conjunction with the interaction of solar radiation with the ice and adjacent tundra and lakes. This information allows us to make an accurate determination of partitioning of solar heating in this zone and provides the basis for IAT feedback modeling. We will also describe some modifications that will be important for generalizing to conditions attendant to increases in the length of the melt season. We propose that this type of study be continued during IPY 2007/08 and that Barrow Ak is an area of critical importance. It offers a key scientific location in combination with superior logistics support and extensive opportunities for K-12 outreach and support of higher education.

  19. The measurement of bromine monoxide from Fairbanks, AK and comparison with OMI/AURA

    NASA Astrophysics Data System (ADS)

    Mount, G. H.; Spinei, E.; Herman, J. R.; Cede, A.; Abuhassan, N.; Simpson, W. R.; McPeters, R. D.; Bhartia, P. K.; Johnson, B. J.; Salawitch, R. J.; Canty, T. P.; Chance, K.; Kurosu, T. P.; Suleiman, R. M.

    2011-12-01

    Enhanced column bromine monoxide in the Arctic has been observed by satellites for some time and is related to bromine "hotspots" that result in nearly complete removal of surface ozone in springtime. Salawitch et al. (2010) have demonstrated that these enhancements show little relation, at times, to satellite-enhanced column BrO. Several recent studies have shown that closure of the budget for total column BrO is achieved by summing observed tropospheric partial column BrO with a calculated stratospheric partial column that accounts for the supply of 7 ppt of Bry from natural, short-lived biogenic bromocarbons to the lowermost stratosphere. However, the burden of Bry in the upper stratosphere in these studies, 26 ppt, is at the upper limit of Bry levels inferred from upper stratospheric BrO. A ground-based NASA-sponsored field campaign was held in Fairbanks, AK in March and April 2011 to measure bromine monoxide and other trace gases by direct sun and multi-axis scattered skylight in combination with daily ozonesondes and OMI/AURA satellite data of BrO. The tropospheric contribution to column BrO should be near zero at this time/location. The campaign was therefore focused on defining the stratospheric BrO burden and evaluating the accuracy of total column BrO reported by OMI. The comparison of the ground-based BrO data with the OMI data is reported. Additionally, the DOAS derivation of BrO is explored using various spectral fitting windows and an error budget compiled showing the sensitivity of the deduced BrO vertical column with instrument-dependent spectral window.

  20. Changes in the IR internal reflection and absorption spectra of AK 60/40 polyamide films after the action of a glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Lunin, V. V.; Rode, S. V.; Samoilovich, V. G.

    2008-12-01

    The modification of surface layers of AK 60/40 polyamide under the action of a gas discharge plasma was studied. Measurements were performed by infrared internal reflection spectroscopy. The results were analyzed to establish possible mechanisms of the interaction of a plasma with the polymer and structural changes in the polymer.

  1. The Entamoeba histolytica, Arp2/3 Complex Is Recruited to Phagocytic Cups through an Atypical Kinase EhAK1

    PubMed Central

    Babuta, Mrigya; Mansuri, M Shahid; Bhattacharya, Sudha; Bhattacharya, Alok

    2015-01-01

    The parasite Entamoeba histolytica is the etiological agent of amoebiasis and phagocytosis plays a key role in virulence of this organism. Signaling pathways involved in activation of cytoskeletal dynamics required for phagocytosis remain to be elucidated. Phagocytosis is initiated with sequential recruitment of EhC2PK, EhCaBP1, EhCaBP3 and an atypical kinase EhAK1 after particle attachment. Here we show that EhARPC1, an essential subunit of the actin branching complex Arp 2/3 is recruited to the phagocytic initiation sites by EhAK1. Imaging, expression knockdown of different molecules and pull down experiments suggest that EhARPC1 interacts with EhAK1 and that it is required during initiation of phagocytosis and phagosome formation. Moreover, recruitment of EhARPC2 at the phagocytosis initiation by EhAK1 is also observed, indicating that the Arp 2/3 complex is recruited. In conclusion, these results suggests a novel mechanism of recruitment of Arp 2/3 complex during phagocytosis in E. histolytica. PMID:26646565

  2. Computer vision

    NASA Technical Reports Server (NTRS)

    Gennery, D.; Cunningham, R.; Saund, E.; High, J.; Ruoff, C.

    1981-01-01

    The field of computer vision is surveyed and assessed, key research issues are identified, and possibilities for a future vision system are discussed. The problems of descriptions of two and three dimensional worlds are discussed. The representation of such features as texture, edges, curves, and corners are detailed. Recognition methods are described in which cross correlation coefficients are maximized or numerical values for a set of features are measured. Object tracking is discussed in terms of the robust matching algorithms that must be devised. Stereo vision, camera control and calibration, and the hardware and systems architecture are discussed.

  3. Availability of ground water on Federal land near the Ak-Chin Indian Reservation, Arizona: a reconnaissance study

    USGS Publications Warehouse

    Wilson, Richard P.

    1979-01-01

    Sufficient ground water to provide about 2.1 million acre-feet in a 25-year period is available for delivery to the Ak-Chin Indian Reservation from Federal land in the Vekol Valley, Waterman Wash area, and Bosque area in south-central Arizona. Withdrawal of 85,000 acre-feet per year as required by the Ak-Chin water-supply act--Public Law 95-328--will greatly deplete the amount of water in storage and may cause land subsidence in the areas. Study concurrent with well-field development will enable design changes to minimize pumping costs , water-level declines, movement of poor-quality water into the well fields, and potential land subsidence and associated earth fissures. Surface and bore-hole geophysical testing, aquifer tests, and the development of simulative mathematical models will accomplish these goals and permit quantitative evaluations of the potential deleterious effects resulting from development of the water supply. (Woodard-USGS)

  4. Transcriptional response of Desulfatibacillum alkenivorans AK-01 to growth on alkanes: insights from RT-qPCR and microarray analyses.

    PubMed

    Herath, Anjumala; Wawrik, Boris; Qin, Yujia; Zhou, Jizhong; Callaghan, Amy V

    2016-05-01

    Microbial transformation of n-alkanes in anaerobic ecosystems plays a pivotal role in biogeochemical carbon cycling and bioremediation, but the requisite genetic machinery is not well elucidated.Desulfatibacillum alkenivorans AK-01 utilizes n-alkanes (C13 to C18) and contains two genomic loci encoding alkylsuccinate synthase (ASS) gene clusters. ASS catalyzes alkane addition to fumarate to form methylalkylsuccinic acids. We hypothesized that the genes in the two clusters would be differentially expressed depending on the alkane substrate utilized for growth. RT-qPCR was used to investigate ass-gene expression across AK-01's known substrate range, and microarray-based transcriptomic analysis served to investigate whole-cell responses to growth on n-hexadecane versus hexadecanoate. RT-qPCR revealed induction of ass gene cluster 1 during growth on all tested alkane substrates, and the transcriptional start sites in cluster 1 were determined via 5'RACE. Induction of ass gene cluster 2 was not observed under the tested conditions. Transcriptomic analysis indicated that the upregulation of genes potentially involved in methylalkylsuccinate metabolism, including methylmalonyl-CoA mutase and a putative carboxyl transferase. These findings provide new directions for studying the transcriptional regulation of genes involved in alkane addition to fumarate, fumarate recycling and the processing of methylalkylsuccinates with regard to isolates, enrichment cultures and ecological datasets. PMID:27009900

  5. New computer architectures

    SciTech Connect

    Tiberghien, J.

    1984-01-01

    This book presents papers on supercomputers. Topics considered include decentralized computer architecture, new programming languages, data flow computers, reduction computers, parallel prefix calculations, structural and behavioral descriptions of digital systems, instruction sets, software generation, personal computing, and computer architecture education.

  6. Computed tomographic arthrography of the normal canine elbow.

    PubMed

    Gendler, Andrew; Keuler, Nicholas S; Schaefer, Susan L

    2015-01-01

    Comprehensive evaluation of canine elbow joint dysfunction includes assessment of articular cartilage, which can noninvasively be performed with contrast arthrography. Aims of this prospective study were to compare positive contrast computed tomographic (CT) arthrography and histomorphometry measures of cartilage thickness in normal canine elbows, and to determine the optimal contrast medium concentration. Thirty-two canine cadaver elbows were examined using multidetector CT, before and after intra-articular administration of iohexol at one of three different concentrations. Articular cartilage thickness was measured on both the CT arthrography images and corresponding histologic specimens. Mean difference (bias) between the CT arthrography and histomorphologic measurements was 0.18 and 0.19 mm in the sagittal and dorsal planes, respectively. Mean bias and precision of CT arthrography measurements made in the sagittal or dorsal reformations were not significantly different from one another. Computed tomographic arthrography measurements from elbows with 75 mg I/ml were significantly larger and had greater bias compared to other contrast medium groups (150 and 37.5 mg I/ml). There was no significant difference in CT arthrography measurement precision between different contrast medium concentrations. Histomorphologic thickness of the articular cartilage overlying the cranial aspect of the ulna (mean 0.32 mm) was significantly thinner than cartilage of the radius (0.36 mm) or humerus (0.36 mm). Findings from this cadaver study indicated that CT arthrography delineates articular cartilage of the normal canine elbow; yields cartilage thickness measures slightly greater than histomorphometry measures; and provides high measurement precision regardless of image plane, contrast medium concentration, or anatomic zone. PMID:25154869

  7. Assessment of liver ablation using cone beam computed tomography

    PubMed Central

    Abdel-Rehim, Mohamed; Ronot, Maxime; Sibert, Annie; Vilgrain, Valérie

    2015-01-01

    AIM: To investigate the feasibility and accuracy of cone beam computed tomography (CBCT) in assessing the ablation zone after liver tumor ablation. METHODS: Twenty-three patients (17 men and 6 women, range: 45-85 years old, mean age 65 years) with malignant liver tumors underwent ultrasound-guided percutaneous tumor ablation [radiofrequency (n = 14), microwave (n = 9)] followed by intravenous contrast-enhanced CBCT. Baseline multidetector computed tomography (MDCT) and peri-procedural CBCT images were compared. CBCT image quality was assessed as poor, good, or excellent. Image fusion was performed to assess tumor coverage, and quality of fusion was rated as bad, good, or excellent. Ablation zone volumes on peri-procedural CBCT and post-procedural MDCT were compared using the non-parametric paired Wilcoxon t-test. RESULTS: Rate of primary ablation effectiveness was 100%. There were no complications related to ablation. Local tumor recurrence and new liver tumors were found 3 mo after initial treatment in one patient (4%). The ablation zone was identified in 21/23 (91.3%) patients on CBCT. The fusion of baseline MDCT and peri-procedural CBCT images was feasible in all patients and showed satisfactory tumor coverage (at least 5-mm margin). CBCT image quality was poor, good, and excellent in 2 (9%), 8 (35%), and 13 (56%), patients respectively. Registration quality between peri-procedural CBCT and post-procedural MDCT images was good to excellent in 17/23 (74%) patients. The median ablation volume on peri-procedural CBCT and post-procedural MDCT was 30 cm3 (range: 4-95 cm3) and 30 cm3 (range: 4-124 cm3), respectively (P-value > 0.2). There was a good correlation (r = 0.79) between the volumes of the two techniques. CONCLUSION: Contrast-enhanced CBCT after tumor ablation of the liver allows early assessment of the ablation zone. PMID:25593467

  8. Computed tomography for pancreatic injuries in pediatric blunt abdominal trauma

    PubMed Central

    Almaramhy, Hamdi Hameed; Guraya, Salman Yousuf

    2012-01-01

    AIM: To evaluate the efficacy of computed tomography scan in diagnosing and grading the pattern of pancreatic injuries in children. METHODS: We conducted a retrospective study to review medical files of children admitted with blunt pancreatic injuries to the Maternity and Children Hospital Al-Madina Al-Munawwarah, Kingdom of Saudi Arabia. The demographic details and mechanisms of injury were recorded. From the database of the Picture Archiving and Communication System of the radiology department, multidetector computed tomography (MDCT) images of the pancreatic injuries, severity, type of injuries and grading of pancreatic injuries were established. RESULTS: Seven patients were recruited in this study over a period of 5 years; 5 males and 2 females with a mean age of 7 years (age range 5-12 years). Fall from height was the most frequent mechanism of injury, reported in 5 (71%), followed by road traffic accident (1 patient, 14%) and cycle handlebar (1 patient, 14%) injuries. According to the American Association for the Surgery of Trauma grading system, 1 (14%) patient sustained Grade I, 1 (14%) Grade II, 3 (42%) Grade III and 2 (28%) patients were found to have Grade V pancreatic injuries. This indicated a higher incidence of severe pancreatic injuries; 5 (71.4%) patients were reported to have Grade III and higher on the injury scale. Three (42%) patients had associated abdominal organ injuries. CONCLUSION: Pediatric pancreatic injuries due to blunt abdominal trauma are rare. The majority of the patients sustained extensive pancreatic injuries. MDCT findings are helpful and reliable in diagnosing and grading the pancreatic injuries. PMID:22905284

  9. Computational Astrophysics

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Astsatryan, H. V.

    2015-07-01

    Present astronomical archives that contain billions of objects, both Galactic and extragalactic, and the vast amount of data on them allow new studies and discoveries. Astrophysical Virtual Observatories (VO) use available databases and current observing material as a collection of interoperating data archives and software tools to form a research environment in which complex research programs can be conducted. Most of the modern databases give at present VO access to the stored information, which makes possible also a fast analysis and managing of these data. Cross-correlations result in revealing new objects and new samples. Very often dozens of thousands of sources hide a few very interesting ones that are needed to be discovered by comparison of various physical characteristics. VO is a prototype of Grid technologies that allows distributed data computation, analysis and imaging. Particularly important are data reduction and analysis systems: spectral analysis, SED building and fitting, modelling, variability studies, cross correlations, etc. Computational astrophysics has become an indissoluble part of astronomy and most of modern research is being done by means of it.

  10. Computational crystallization.

    PubMed

    Altan, Irem; Charbonneau, Patrick; Snell, Edward H

    2016-07-15

    Crystallization is a key step in macromolecular structure determination by crystallography. While a robust theoretical treatment of the process is available, due to the complexity of the system, the experimental process is still largely one of trial and error. In this article, efforts in the field are discussed together with a theoretical underpinning using a solubility phase diagram. Prior knowledge has been used to develop tools that computationally predict the crystallization outcome and define mutational approaches that enhance the likelihood of crystallization. For the most part these tools are based on binary outcomes (crystal or no crystal), and the full information contained in an assembly of crystallization screening experiments is lost. The potential of this additional information is illustrated by examples where new biological knowledge can be obtained and where a target can be sub-categorized to predict which class of reagents provides the crystallization driving force. Computational analysis of crystallization requires complete and correctly formatted data. While massive crystallization screening efforts are under way, the data available from many of these studies are sparse. The potential for this data and the steps needed to realize this potential are discussed. PMID:26792536

  11. Computer vision

    SciTech Connect

    Not Available

    1982-01-01

    This paper discusses material from areas such as artificial intelligence, psychology, computer graphics, and image processing. The intent is to assemble a selection of this material in a form that will serve both as a senior/graduate-level academic text and as a useful reference to those building vision systems. This book has a strong artificial intelligence flavour, emphasising the belief that both the intrinsic image information and the internal model of the world are important in successful vision systems. The book is organised into four parts, based on descriptions of objects at four different levels of abstraction. These are: generalised images-images and image-like entities; segmented images-images organised into subimages that are likely to correspond to interesting objects; geometric structures-quantitative models of image and world structures; relational structures-complex symbolic descriptions of image and world structures. The book contains author and subject indexes.

  12. Positron emission tomography/computed tomography.

    PubMed

    Townsend, David W

    2008-05-01

    Accurate anatomical localization of functional abnormalities obtained with the use of positron emission tomography (PET) is known to be problematic. Although tracers such as (18)F-fluorodeoxyglucose ((18)F-FDG) visualize certain normal anatomical structures, the spatial resolution is generally inadequate for accurate anatomic localization of pathology. Combining PET with a high-resolution anatomical imaging modality such as computed tomography (CT) can resolve the localization issue as long as the images from the two modalities are accurately coregistered. However, software-based registration techniques have difficulty accounting for differences in patient positioning and involuntary movement of internal organs, often necessitating labor-intensive nonlinear mapping that may not converge to a satisfactory result. Acquiring both CT and PET images in the same scanner obviates the need for software registration and routinely provides accurately aligned images of anatomy and function in a single scan. A CT scanner positioned in line with a PET scanner and with a common patient couch and operating console has provided a practical solution to anatomical and functional image registration. Axial translation of the couch between the 2 modalities enables both CT and PET data to be acquired during a single imaging session. In addition, the CT images can be used to generate essentially noiseless attenuation correction factors for the PET emission data. By minimizing patient movement between the CT and PET scans and accounting for the axial separation of the two modalities, accurately registered anatomical and functional images can be obtained. Since the introduction of the first PET/CT prototype more than 6 years ago, numerous patients with cancer have been scanned on commercial PET/CT devices worldwide. The commercial designs feature multidetector spiral CT and high-performance PET components. Experience has demonstrated an increased level of accuracy and confidence in the

  13. Integrated Airborne and In-Situ Measurements Over Land-Fast Ice Near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Richter-Menge, J.; Abelev, A.; Liang, R.; Ball, D.; Claffey, K. J.; Hebert, D. A.; Jones, K.

    2015-12-01

    The Naval Research Laboratory has collected two field seasons of integrated airborne and in-situ measurements over multiple sites of floating, but land-fast ice north of Barrow, AK. During the first season in March of 2014 the Cold Regions Research and Engineering Laboratory led the on-ice group including NRL personnel and Naval Academy midshipmen. The second season (March 2015) included only NRL scientists and midshipmen. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439), a low-frequency SAR (P-band in 2014 and P and L bands in 2015) and a snow/Ku radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The CReSIS radar was updated in 2015 to integrate the snow and Ku radars into a single continuous chirp, thus improving resolution. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects a sites generally consisting of a 2 km long profile of Magnaprobe and EM31 measurements with periodic boreholes. A 60 m x 400 m swath of Magnaprobe measurements was centered on this profile. Airborne data were collected on multiple overflights of the transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The SAR imaged the ice beneath the snow and the snow/Ku radar measured snow thickness. The freeboard measurements and snow thickness are used to estimate ice thickness via isostasy and density estimates. Comparisons and processing methodology will be shown. The results of this ground-truth experiment will inform our analysis of grids of airborne data collected

  14. Integrated Airborne and In-Situ Measurements over Land-Fast Ice near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Gardner, J. M.; Liang, R.; Ball, D.; Richter-Menge, J.; Claffey, K. J.; Abelev, A.; Hebert, D. A.; Jones, K.

    2014-12-01

    During March of 2014, the Naval Research Laboratory and the Cold Regions Research and Engineering Laboratory collected an integrated set of airborne and in-situ measurements over two areas of floating, but land-fast ice near the coast of Barrow, AK. The near-shore site was just north of Point Barrow, and the "offshore" site was ~ 20 km east of Point Barrow. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439) and a snow radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects at both sites consisting of a 2 km long profile of snow depth and ice thickness measurements with periodic boreholes. A 60 m x 400 m swath of snow depth measurements was centered on this profile. Airborne data were collected on five overflights of the two transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The radar measured snow thickness. The freeboard and snow thickness measurements are used to estimate ice thickness via isostasy and density estimates. The central swath of in situ snow depth data allows examination of the effects of cross-track variations considering the relatively large footprint of the snow radar. Assuming a smooth, flat surface the radar range resolution in air is < 4 cm, but the along-track sampling distance is ~ 3 m after unfocussed SAR processing. The width of the footprint varies from ~ 9 m up to about 40 m (beam-limited) for uneven surfaces. However, the radar could not resolve snow thickness

  15. Physical analysis of breast cancer using dual-source computed tomography

    NASA Astrophysics Data System (ADS)

    Kim, H. J.; Lee, H. K.; Cho, J. H.

    2014-12-01

    This study was aimed to analyze various physical characteristics of breast cancer using dual-source computed tomography (CT). A phantom study and a clinical trial were performed in order and a 64-multidetector CT device was used for the examinations. In the phantom study, single-source (SS) CT was set up with a conventional scanning condition that is usually applied for breast CT examination and implementation was done at tube voltage of 120 kVp. Dual-source CT acquired images by irradiating X-ray sources with fast switching between two kilovoltage settings (80 and 140 kVp). After scanning, Hounsfield Unit (HU) values and radiation doses in a region of interest were measured and analyzed. In the clinical trial, the HU values were measured and analyzed after single-source computed tomography (SSCT) and dual-source CT in patients diagnosed with breast cancer. Also, the tumor size measured by dual-source CT was compared with the actual tumor size. The phantom study determined that the tumor region was especially measured by dual-source CT, while nylon fiber and specks region were especially measured by SSCT. The radiation dose was high with dual-source CT. The clinical trial showed a higher HU value of cancerous regions when scanned by dual-source CT compared with SSCT.

  16. The Spectrum of Presentations of Cryptogenic Organizing Pneumonia in High Resolution Computed Tomography

    PubMed Central

    Mehrian, Payam; Shahnazi, Makhtoom; Dahaj, Ali Ahmadi; Bizhanzadeh, Sorour; Karimi, Mohammad Ali

    2014-01-01

    Summary Background Various radiologic patterns of cryptogenic organizing pneumonia (COP) in X-rays have been reported for more than 20 years, and later, in computed tomography scans. The aim of the present study was to describe the spectrum of radiologic findings on high resolution computed tomography (HRCT) scans in patients with COP. Material/Methods HRCT scans of 31 sequential patients (mean age: 54.3±11 years; 55% male) with biopsy-proven COP in a tertiary lung center between 2009 and 2012 were reviewed by two experienced pulmonary radiologists with almost perfect interobserver agreement (kappa=0.83). Chest HRCTs from the lung apex to the base were performed using a 16-slice multi-detector CT scanner. Results The most common HRCT presentation of COP was ground-glass opacity (GGO) in 83.9% of cases, followed by consolidation in 71%. Both findings were mostly asymmetric bilateral and multifocal. Other common findings were the reverse halo (48.4%), parenchymal bands (54.8%) and subpleural bands (32.3%). Pulmonary nodules were found in about one-third of patients and were frequently smaller than 5 mm in diameter. Both GGOs and consolidations were revealed more often in the lower lobes. Conclusions The main presentations of COP on HRCT include bilateral GGOs and consolidations in the lower lobes together with the reverse halo sign. PMID:25493105

  17. Application of three-dimensional computed tomography in craniofacial clinical practice and research.

    PubMed

    Anderson, P J; Yong, R; Surman, T L; Rajion, Z A; Ranjitkar, S

    2014-06-01

    Following the invention of the first computed tomography (CT) scanner in the early 1970s, many innovations in three-dimensional (3D) diagnostic imaging technology have occurred, leading to a wide range of applications in craniofacial clinical practice and research. Three-dimensional image analysis provides superior and more detailed information compared with conventional plain two-dimensional (2D) radiography, with the added benefit of 3D printing for preoperative treatment planning and regenerative therapy. Current state-of-the-art multidetector CT (MDCT), also known as medical CT, has an important role in the diagnosis and management of craniofacial injuries and pathology. Three-dimensional cone beam CT (CBCT), pioneered in the 1990s, is gaining increasing popularity in dental and craniofacial clinical practice because of its faster image acquisition at a lower radiation dose, but sound guidelines are needed to ensure its optimal clinical use. Recent innovations in micro-computed tomography (micro-CT) have revolutionized craniofacial biology research by enabling higher resolution scanning of teeth beyond the capabilities of MDCT and CBCT, presenting new prospects for translational clinical research. Even after four decades of refinement, CT technology continues to advance and broaden the horizons of craniofacial clinical practice and phenomics research. PMID:24611727

  18. What can computed tomography and magnetic resonance imaging tell us about ventilation?

    PubMed Central

    Simon, Brett A.; Kaczka, David W.; Bankier, Alexander A.

    2012-01-01

    This review provides a summary of pulmonary functional imaging approaches for determining pulmonary ventilation, with a specific focus on multi-detector x-ray computed tomography and magnetic resonance imaging (MRI). We provide the important functional definitions of pulmonary ventilation typically used in medicine and physiology and discuss the fact that some of the imaging literature describes gas distribution abnormalities in pulmonary disease that may or may not be related to the physiological definition or clinical interpretation of ventilation. We also review the current state-of-the-field in terms of the key physiological questions yet unanswered related to ventilation and gas distribution in lung disease. Current and emerging imaging research methods are described, including their strengths and the challenges that remain to translate these methods to more wide-spread research and clinical use. We also examine how computed tomography and MRI might be used in the future to gain more insight into gas distribution and ventilation abnormalities in pulmonary disease. PMID:22653989

  19. Computational Cosmology

    NASA Astrophysics Data System (ADS)

    Abel, Tom

    2013-01-01

    Gravitational instability of small density fluctuations, possibly created during an early inflationary period, is the key process leading to the formation of all structure in the Universe. New numerical algorithms have recently enabled much progress in understanding the relevant physical processes dominating the first billion years of structure formation. Computational cosmologists are attempting to simulate on their supercomputers how galaxies come about. In recent years first attempts trying to follow the formation and eventual death of every single star in these model galaxies has become to be within reach. The models now include gravity for both dark matter and baryonic matter, hydrodynamics, follow the radiation from massive stars and its impact in shaping the surrounding material, gas chemistry and all the key radiative atomic and molecular physics determining the thermal state of the model gas. In a small number of cases even the rold of magnetic fields on galactic scales is being studied. At the same time we are learning more about the limitations of certain numerical techniques and developing new schemes to more accurately follow the interplay of these many different physical processes. This talk is in two parts. First we consider a birds eye view of the relevant physical processes relevant for structure formation and potential approaches in solving the relevant equations efficiently and accurately on modern supercomputers. Secondly, we focus in on one of those processes. Namely the intricate and fascinating dynamics of the likely collsionless fluid dynamics of dark matter. A novel way of following the intricate evolution of such collisionless fluids in phase space is allowing us to construct new numerical methods to help understand the nature of dark matter halos as well as problems in astrophysical and terrestial plasmas.

  20. Computer Technology and Education.

    ERIC Educational Resources Information Center

    Senter, Joy

    1981-01-01

    Examines educational tasks in general computing, including computer-assisted instruction, computer-managed instruction, word processing, secretarial and business applications, time sharing, and networking to larger computers. (CT)

  1. Computer security in DOE distributed computing systems

    SciTech Connect

    Hunteman, W.J.

    1990-01-01

    The modernization of DOE facilities amid limited funding is creating pressure on DOE facilities to find innovative approaches to their daily activities. Distributed computing systems are becoming cost-effective solutions to improved productivity. This paper defines and describes typical distributed computing systems in the DOE. The special computer security problems present in distributed computing systems are identified and compared with traditional computer systems. The existing DOE computer security policy supports only basic networks and traditional computer systems and does not address distributed computing systems. A review of the existing policy requirements is followed by an analysis of the policy as it applies to distributed computing systems. Suggested changes in the DOE computer security policy are identified and discussed. The long lead time in updating DOE policy will require guidelines for applying the existing policy to distributed systems. Some possible interim approaches are identified and discussed. 2 refs.

  2. Making the Computer Neuter.

    ERIC Educational Resources Information Center

    Sanders, Jo Shuchat

    1985-01-01

    Summarizes findings of Computer Equity Training Project studies concerning female presence in computer magazines; home computer use variability by sex; student software evaluation; and influence on computer use of teacher gender, gender of other computer users, and work environment. Successful classroom computer equity approaches based on these…

  3. Computed tomographic quantification of canine adrenal gland volume and attenuation.

    PubMed

    Bertolini, Giovanna; Furlanello, Tommaso; De Lorenzi, Davide; Caldin, Marco

    2006-01-01

    We conducted a retrospective study in presumed normal dogs to determine the adrenal gland attenuation and volume values. Multidetector computer tomography (MDCT 16) analysis of the gland was carried out in 48 adult dogs without evidence of adrenal gland disease that underwent CT examination for acute spinal injuries. The mean nonenhanced attenuation value +/- SD of the left adrenal gland was 36.0 +/- 5.3 HU (range: 22.0-42.0 HU). The mean nonenhanced attenuation value +/- SD of the right gland was 34.3 +/- 7.0 HU (range: 20.4-48.6HU). The mean enhanced attenuation value +/- SD were: left gland 101.5 +/- 10.6HU (range: 86.8-128.0 HU), and right gland 97.4 +/- 12.4 HU (range: 58.9-123.6 HU). The mean CT volume +/- SD were: left gland was 0.60 cm3 (range: 0.20-0.95; SD 0.17), and right gland (0.55cm3, range: 0.22-1.01; SD 0.19). Attenuation values and volume data were related to age, weight, and gender, using ANOVA. There was no statistically significant difference between the left and right side or in adrenal measurements, because of body weight class effects. The animal effect was the most important source of variation for all adrenal measurements. Based on our study, CT is an effective method for assessing adrenal characteristics in the dog. Normative CT data are provided to allow estimation of normal adrenal gland size and volume. PMID:17009504

  4. Optimization of Free-Breathing Whole-Heart 3D Cardiac MRI at 3Tesla to Identify Coronary Vein Anatomy and to Compare with Multi-Detector Computed Tomography

    PubMed Central

    Ibrahim, Wael G.; El Khouli, Riham H.; Abd-Elmoniem, Khaled Z.; Matta, Jatin Raj; McAreavey, Dorothea; Gharib, Ahmed M

    2014-01-01

    Objective This study optimizes use of 3T MRI to delineate coronary venous anatomy, and compares 3T MRI with MDCT measurements. Methods The study population included 37 consecutive subjects (22 men, 19-71 years). Whole-heart contrast-enhanced MRI images at 3T were acquired using segmented k-space gradient echo with inversion recovery prepared technique. MDCT images were obtained using nonionic iodinated contrast. Results The coronary sinus, and great cardiac, posterior interventricular, and anterior interventricular veins were visualized in 100% of cases by both MRI and MDCT. Detection of the posterior vein of left ventricle and left marginal vein by MRI was 97% and 81% respectively. Bland Altman plots showed agreement in ostial diameter measured by both modalities with correlation coefficients ranging 0.5-0.76. Vein length and distances also agreed closely. Conclusion Free-breathing whole-heart 3D MRI at 3T provides high spatial resolution images and could offer an alternative imaging technique instead of MDCT scans. PMID:24983436

  5. Activation of the EIF2AK4-EIF2A/eIF2α-ATF4 pathway triggers autophagy response to Crohn disease-associated adherent-invasive Escherichia coli infection

    PubMed Central

    Bretin, Alexis; Carrière, Jessica; Dalmasso, Guillaume; Bergougnoux, Agnès; B'chir, Wafa; Maurin, Anne-Catherine; Müller, Stefan; Seibold, Frank; Barnich, Nicolas; Bruhat, Alain; Darfeuille-Michaud, Arlette; Nguyen, Hang Thi Thu

    2016-01-01

    ABSTRACT The intestinal mucosa of Crohn disease (CD) patients is abnormally colonized by adherent-invasive E. coli (AIEC). Upon AIEC infection, autophagy is induced in host cells to restrain bacterial intracellular replication. The underlying mechanism, however, remains unknown. Here, we investigated the role of the EIF2AK4-EIF2A/eIF2α-ATF4 pathway in the autophagic response to AIEC infection. We showed that infection of human intestinal epithelial T84 cells with the AIEC reference strain LF82 activated the EIF2AK4-EIF2A-ATF4 pathway, as evidenced by increased phospho-EIF2AK4, phospho-EIF2A and ATF4 levels. EIF2AK4 depletion inhibited autophagy activation in response to LF82 infection, leading to increased LF82 intracellular replication and elevated pro-inflammatory cytokine production. Mechanistically, EIF2AK4 depletion suppressed the LF82-induced ATF4 binding to promoters of several autophagy genes including MAP1LC3B, BECN1, SQSTM1, ATG3 and ATG7, and this subsequently inhibited transcription of these genes. LF82 infection of wild-type (WT), but not eif2ak4−/−, mice activated the EIF2AK4-EIF2A-ATF4 pathway, inducing autophagy gene transcription and autophagy response in enterocytes. Consequently, eif2ak4−/− mice exhibited increased intestinal colonization by LF82 bacteria and aggravated inflammation compared to WT mice. Activation of the EIF2AK4-EIF2A-ATF4 pathway was observed in ileal biopsies from patients with noninflamed CD, and this was suppressed in inflamed CD, suggesting that a defect in the activation of this pathway could be one of the mechanisms contributing to active disease. In conclusion, we show that activation of the EIF2AK4-EIF2A-ATF4 pathway upon AIEC infection serves as a host defense mechanism to induce functional autophagy to control AIEC intracellular replication. PMID:26986695

  6. Quantifying Seasonal Dynamics of Surface Inundation on the Barrow Peninsula, AK

    NASA Astrophysics Data System (ADS)

    Wilson, C. J.; Chen, M.; Rowland, J. C.; Altmann, G. L.

    2013-12-01

    Wetlands are commonly distributed across the Arctic Coastal Plain of Northern Alaska, a low-gradient region underlain by continuous permafrost. They are important components of the global biogeochemical cycle because of the large carbon stores and potential release of this carbon as CO2 and CH4 due to climate change. These wetlands are recharged seasonally by water from snowmelt and summer rainfall, but their area shrinks significantly during the snow free season every year. While seasonal and long-term thaw lake area change is well documented, the seasonal dynamics of smaller wetland features including polygon ponds is poorly quantified. Understanding and quantifying the factors driving and controlling the spatial redistribution of surface water will help in the parameterization of models and evaluation of predictions of water, energy and carbon budgets for lowland Arctic regions. In this study, we used high spatial resolution images (WorldView 2 and QuickBird) on 9 dates from 2006-2012 to investigate the seasonal change and spatial pattern of surface water area for a 4700 ha wetland near Barrow, AK. We found that the surface water area decreased dramatically throughout the summer each year. For example, it decreased by 782 ha (74%) from June 24 to July 21 and continued to decrease by 153 ha (54%) from July 21 to August 4 in 2010. The correlation between the seasonal change in surface water area and local precipitation minus evapotranspiration was low, indicating that the local water balance had little direct control on the change in surface water area through the Summer. Instead, the post snowmelt change in the area of surface inundation as a function of time was well fit by the equation for hydrograph recession, indicating that drainage of ponded water in July and August may be primarily controlled by shallow subsurface flow rather than through evapotranspiration, even in this very low gradient environment. The rate of drainage of surface water was significantly

  7. Quinolone-Resistant Escherichia coli O127a:K63 Serotype with an Extended-Spectrum-Beta-Lactamase Phenotype from a Food Poisoning Outbreak in China

    PubMed Central

    Hao, Rongzhang; Qiu, Shaofu; Yang, Guang; Su, Wenli; Song, Lixue; Zhang, Jia; Chen, Jiaxu; Jia, Leili; Wang, Ligui

    2012-01-01

    We report an atypical enteropathogenic Escherichia coli O127a:K63 strain with resistance to quinolones and extended-spectrum cephalosporins isolated from a 2010 food poisoning outbreak involving 112 adults in China. Two resistance genes [blaCTX-M-15, aac(6′)-Ib-c] and five mutations (two in gyrA, two in parC, one in parE) coexisted in this enteropathogenic E. coli strain. PMID:22553233

  8. Detergent-, solvent- and salt-compatible thermoactive alkaline serine protease from halotolerant alkaliphilic Bacillus sp. NPST-AK15: purification and characterization.

    PubMed

    Ibrahim, Abdelnasser S S; Al-Salamah, Ali A; El-Badawi, Yahya B; El-Tayeb, Mohamed A; Antranikian, Garabed

    2015-09-01

    Alkaline protease produced by the halotolerant alkaliphilic Bacillus sp. strain NPST-AK15 was purified to homogeneity by the combination of ammonium sulfate precipitation, anion-exchange and gel permeation chromatography. The purified enzyme was a monomeric protein with an estimated molecular weight of 32 kDa. NPST-AK15 protease was highly active and stable over a wide pH range, with a maximal activity at pH 10.5. The enzyme showed optimum activity at 60 °C and was stable at 30-50 °C for at least 1 h. Thermal stability of the purified protease was substantially improved by CaCl2 (1.1- to 6.6-fold). The K m, V max and k cat values for the enzyme were 2.5 mg ml(-1), 42.5 µM min(-1) mg(-1), and 392.46 × 10(3) min(-1), respectively. NPST-AK15 protease activity was strongly inhibited by PMSF, suggesting that the enzyme is a serine protease. The enzyme was highly stable in NaCl up to 20 % (w/v). Moreover, the purified enzyme was stable in several organic solvents such as diethyl ether, benzene, toluene, and chloroform. In addition, it showed high stability and compatibility with a wide range of surfactants and commercial detergents and was slightly activated by hydrogen peroxide. These features of NPST-AK15 protease make this enzyme a promising candidate for application in the laundry and pharmaceutical industries. PMID:26159877

  9. CAA: Computer Assisted Athletics.

    ERIC Educational Resources Information Center

    Hall, John H.

    Computers have been used in a variety of applications for athletics since the late 1950's. These have ranged from computer-controlled electric scoreboards to computer-designed pole vaulting poles. Described in this paper are a computer-based athletic injury reporting system and a computer-assisted football scouting system. The injury reporting…

  10. The Old Computers' Home.

    ERIC Educational Resources Information Center

    Angier, Natalie

    1983-01-01

    The Computer Museum in Marlborough, Massachusetts houses old and not-so-old calculators, famous old computers and parts of computers, photographs and assorted memorabilia, computer-generated murals, and even a computer made of Tinkertoys that plays tick-tack-toe. The development of the museum and selected exhibits is described. (Author/JN)

  11. The assumptions of computing

    SciTech Connect

    Huggins, J.K.

    1994-12-31

    The use of computers, like any technological activity, is not content-neutral. Users of computers constantly interact with assumptions regarding worthwhile activity which are embedded in any computing system. Directly questioning these assumptions in the context of computing allows us to develop an understanding of responsible computing.

  12. Democratizing Computer Science

    ERIC Educational Resources Information Center

    Margolis, Jane; Goode, Joanna; Ryoo, Jean J.

    2015-01-01

    Computer science programs are too often identified with a narrow stratum of the student population, often white or Asian boys who have access to computers at home. But because computers play such a huge role in our world today, all students can benefit from the study of computer science and the opportunity to build skills related to computing. The…

  13. Overview of Computer Hardware.

    ERIC Educational Resources Information Center

    Tidball, Charles S.

    1980-01-01

    Reviews development in electronics technology of digital computers, considering the binary number representation, miniaturization of electronic components, cost and space requirements of computers, ways in which computers are used, and types of computers appropriate for teaching computer literacy and demonstrating physiological simulation. (CS)

  14. Tying into Computers.

    ERIC Educational Resources Information Center

    Canipe, Stephen L.

    Topics in this paper include: sources of computer programs, public domain software, copyright violations, purposes of computers in classrooms (drill/practice and interactive learning), computer assisted instruction, flow charts, and computer clubs (such as App-le-kations in Charlotte, North Carolina). A complete listing of two computer programs…

  15. Computer Inequities in Opportunities for Computer Literacy.

    ERIC Educational Resources Information Center

    Anderson, Ronald E.; And Others

    The Science Assessment and Research Project conducted an assessment of the opportunities for computer learning in the nation's schools. As part of this study, 15,847 junior and senior high school students (13 and 17 years old) responded to a questionnaire regarding computers and computer usage. This is a summary of the findings: Opportunities for…

  16. computePk: Power spectrum computation

    NASA Astrophysics Data System (ADS)

    L'Huillier, Benjamin

    2014-03-01

    ComputePk computes the power spectrum in cosmological simulations. It is MPI parallel and has been tested up to a 4096^3 mesh. It uses the FFTW library. It can read Gadget-3 and GOTPM outputs, and computes the dark matter component. The user may choose between NGP, CIC, and TSC for the mass assignment scheme.

  17. Computational thinking and thinking about computing

    PubMed Central

    Wing, Jeannette M.

    2008-01-01

    Computational thinking will influence everyone in every field of endeavour. This vision poses a new educational challenge for our society, especially for our children. In thinking about computing, we need to be attuned to the three drivers of our field: science, technology and society. Accelerating technological advances and monumental societal demands force us to revisit the most basic scientific questions of computing. PMID:18672462

  18. Scanning protocol optimization and dose evaluation in coronary stenosis using multi-slices computed tomography

    NASA Astrophysics Data System (ADS)

    Huang, Yung-hui; Chen, Chia-lin; Sheu, Chin-yin; Lee, Jason J. S.

    2007-02-01

    Cardiovascular diseases are the most common incidence for premature death in developed countries. A major fraction is attributable to atherosclerotic coronary artery disease, which may result in sudden cardiac failure. A reduction of mortality caused by myocardial infarction may be achieved if coronary atherosclerosis can be detected and treated at an early stage before symptoms occur. Therefore, there is need for an effective tool that allows identification of patients at increased risk for future cardiac events. The current multi-detector CT has been widely used for detection and quantification of coronary calcifications as a sign of coronary atherosclerosis. The aim of this study is to optimize the diagnostic values and radiation exposure in coronary artery calcium-screening examination using multi-slice CT (MSCT) with different image scan protocols. The radiation exposure for all protocols is evaluated by using computed tomography dose index (CTDI) phantom measurements. We chose an optimal scanning protocol and evaluated patient radiation dose in the MSCT coronary artery screenings and preserved its expecting diagnostic accuracy. These changes make the MSCT have more operation flexibility and provide more diagnostic values in current practice.

  19. Computer-aided detection of small bowel strictures in CT enterography

    NASA Astrophysics Data System (ADS)

    Sainani, Nisha I.; Näppi, Janne J.; Sahani, Dushyant V.; Yoshida, Hiroyuki

    2011-03-01

    The workflow of CT enterography in an emergency setting could be improved significantly by computer-aided detection (CAD) of small bowel strictures to enable even non-expert radiologists to detect sites of obstruction rapidly. We developed a CAD scheme to detect strictures automatically from abdominal multi-detector CT enterography image data by use of multi-scale template matching and a blob detector method. A pilot study was performed on 15 patients with 22 surgically confirmed strictures to study the effect of the CAD scheme on observer performance. The 77% sensitivity of an inexperienced radiologist assisted by CAD was comparable with the 81% sensitivity of an unaided expert radiologist (p=0.07). The use of CAD reduced the reading time to identify strictures significantly (p<0.0001). Most of the false-positive CAD detections were caused by collapsed bowel loops, approximated bowel wall, muscles, or vessels, and they were easy to dismiss. The results indicate that CAD could provide radiologists with a rapid and accurate interpretation of strictures to improve workflow in an emergency setting.

  20. Effective Doses in Four-Dimensional Computed Tomography for Lung Radiotherapy Planning

    SciTech Connect

    Mori, Shinichiro Ko, Susumu; Ishii, Takayoshi; Nishizawa, Kanae

    2009-04-01

    The recent broad adoption of 4-D computed tomography (4DCT) scanning in radiotherapy has allowed the accurate determination of the target volume of tumors by minimizing image degradation caused by respiratory motion. Although the radiation exposure of the treatment beam is significantly greater than that of CT scans used for treatment planning, it is important to recognize and optimize the radiation exposure in 4DCT from the radiological protection point of view. Here, radiation exposure in 4DCT was measured with a 16 multidetector CT. Organ doses were measured using thermoluminescence radiation dosimeter chips inserted at respective anatomical sites of an anthropomorphic phantom. Results were compared with those with the helical CT scan mode. The effective dose measured for 4DCT was 24.7 mSv, approximately four times higher than that for helical CT. However, the increase in treatment accuracy afforded by 4DCT means its use in radiotherapy is inevitable. The patient exposure in the 4DCT could be of value by clarifying the advantage of the treatment planning using 4DCT.