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Visual Analysis (visual + analysis)
Selected AbstractsInvestigative Visual Analysis of Global TerrorismCOMPUTER GRAPHICS FORUM, Issue 3 2008Xiaoyu Wang Abstract Recent increases in terrorist activity around the world have made analyzing and understanding such activities more critical than ever. With the help of organizations such as the National Center for the Study of Terrorism and Responses to Terrorism (START), we now have detailed historical information on each terrorist event around the world since 1970. However, due to the size and complexity of the data, identifying terrorists' patterns and trends has been difficult. To better enable investigators in understanding terrorist activities, we propose a visual analytical system that focuses on depicting one of the most fundamental concepts in investigative analysis, the five W's (who, what, where, when, and why). Views in our system are highly correlated, and each represents one of the W's. With this approach, an investigator can interactively explore terrorist activities efficiently and discover reasons of attacks (why) by identifying patterns temporally (when), geo-spatially (where), between multiple terrorist groups (who), and across different methods or modes of attacks (what). By coupling a global perspective with the details gleaned from asking these five questions, the system allows analysts to think both tactically and strategically. [source] Selecting Nanotechnology-Based Composites Using Colorimetric and Visual Analysis for the Restoration of Anterior Dentition: A Case ReportJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2004FRANK J. MILNAR DDS ABSTRACT Currently it is possible to use direct composites and layering techniques to replicate the complex internal structures, visible shape, color, and surface anatomy of natural teeth. To do so, however, requires dentists to understand the principles of nature and the science of dental materials to determine the most suitable restorative material for a specific indication. By incorporating relatively new technologies,colorimetric analysis, which provides computerized shade guide definitions of a tooth and essential information to verify shade mapping, and a new nanotechnology-based direct composite,into composite layering techniques, dentists can more predictably replicate the esthetics of natural teeth. This article presents a case in which both technologies, used in combination with a composite layering technique, contributed to the esthetic and functional restoration of the maxillary central incisors. [source] Visual Analysis or Semi-Automated Gray-Scale-Based Color Mapping of the Carotid Plaque: Which Method Correlates the Best with the Presence of Cerebrovascular Symptoms and/or Lesions on MRI?JOURNAL OF NEUROIMAGING, Issue 2 2009Isabelle Momjian MD ABSTRACT BACKGROUND AND PURPOSE To determine the correlation between carotid plaque morphology, assessed by two different ultrasonographic methods, and presence of cerebrovascular events and/or lesions on magnetic resonance imaging (MRI). PATIENTS AND METHODS Visual analysis of plaque echogenicity using a five-type classification was performed. Further, a semi-automated gray-scale-based color mapping of the whole plaque and of its surface was achieved. RESULTS There were 31 (35%) symptomatic (23 strokes and 8 transitory ischemic attacks [TIAs]) and 58 (65%) asymptomatic carotid stenoses. MRI lesions related to the carotid stenosis if located in the ipsilateral cortical, subcortical, or watershed area, were present in 27 cases (30%). In a multivariate logistic regression model, degree of stenosis (P= .03) and a predominant red color on the surface (P= .04) were independent factors associated with the presence of cerebrovascular events and/or lesions on MRI. Sensitivity and specificity were, respectively, 80% and 63% by combining degree of stenosis and color mapping of plaque surface. CONCLUSION Degree of stenosis and a predominant red color on plaque surface were independent factors associated with the presence of cerebrovascular events and/or lesions on MRI. No correlation was observed with any particular type of plaque based on visual analysis alone. [source] Early detection of bone infection and differentiation from post-surgical inflammation using 2-deoxy-2-[18F]-fluoro- D -glucose positron emission tomography (FDG-PET) in an animal modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2005Laurie Jones-Jackson Abstract Diagnosing bone infection in the context of post-surgical inflammation is problematic since many of the early signs of infection are similar to normal post-surgical changes. We used a rabbit osteomyelitis model to evaluate the use of 2-deoxy-2-[18F]-fluoro- D -glucose positron emission tomography (FDG-PET) as a means of detecting post-operative infection in the context of post-surgical inflammation. Comparisons were made between infected and non-infected rabbits in which infection with Staphylococcus aureus was initiated at the time of surgery. Weekly PET scans were obtained 30 and 60 min after the introduction of FDG and analyzed based on standardized uptake values (SUV) at the surgical site and visual assessment of the presence or absence of infection. Concurrent X-rays were taken immediately prior to scanning. At 4 weeks post-operatively, animals were sacrificed for histologic and bacteriologic confirmation of infection. Uptake of FDG was evident in the bone of all rabbits on day 1 post-surgery, however, SUV comparisons from the surgical site could not be used to distinguish between the infected and uninfected groups until day 15. Visual analysis of FDG-PET scans revealed a significant difference (p < 0.01) between the infected and uninfected groups as early as day 8. This was due in part to the ability to visualize regional lymph nodes by FDG-PET.© 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Incident investigation: Process to identify root causes of mechanical failures,PROCESS SAFETY PROGRESS, Issue 1 2006A. M. (Art) Dowell III P.E. This paper describes an actual incident investigation into unexpected premature failure of sealed diaphragm pressure transmitters in a chemical process. Some nontypical investigation tools from the CCPS Guidelines for Investigating Chemical Process Incidents (2nd edition) were used. A typical failure allowed a release of a corrosive process fluid with potential injury to personnel. The failures also required a shutdown of the process with loss of production. The cause of the problem was elusive; pressure transmitters from the same manufacturer had no problems in a similar process unit, although component designs differed between the two units. The investigation included confirmation of materials of construction, photographic and visual analyses of failed components, simulation of assembly of the pressure transmitter in the process and measurement of torque values, and brainstorming of possible failure mechanisms. Several hypotheses were tested using a fact,hypothesis matrix to determine most likely cause scenarios. Similarly, a matrix was used to illustrate which scenarios could be prevented by which corrective actions. The investigation included a root cause analysis tree to confirm cause scenarios. The paper discusses the incident investigation process, including diversity of skills on the investigation team, and how each of the tools was used. The paper also discusses the communication of the findings to operations. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2006 [source] A Screen Space Quality Method for Data AbstractionCOMPUTER GRAPHICS FORUM, Issue 3 2008J. Johansson Abstract The rendering of large data sets can result in cluttered displays and non-interactive update rates, leading to time consuming analyses. A straightforward solution is to reduce the number of items, thereby producing an abstraction of the data set. For the visual analysis to remain accurate, the graphical representation of the abstraction must preserve the significant features present in the original data. This paper presents a screen space quality method, based on distance transforms, that measures the visual quality of a data abstraction. This screen space measure is shown to better capture significant visual structures in data, compared with data space measures. The presented method is implemented on the GPU, allowing interactive creation of high quality graphical representations of multivariate data sets containing tens of thousands of items. [source] Interactive Visualization with Programmable Graphics HardwareCOMPUTER GRAPHICS FORUM, Issue 3 2002Thomas Ertl One of the main scientific goals of visualization is the development of algorithms and appropriate data models which facilitate interactive visual analysis and direct manipulation of the increasingly large data sets which result from simulations running on massive parallel computer systems, from measurements employing fast high-resolution sensors, or from large databases and hierarchical information spaces. This task can only be achieved with the optimization of all stages of the visualization pipeline: filtering, compression, and feature extraction of the raw data sets, adaptive visualization mappings which allow the users to choose between speed and accuracy, and exploiting new graphics hardware features for fast and high-quality rendering. The recent introduction of advanced programmability in widely available graphics hardware has already led to impressive progress in the area of volume visualization. However, besides the acceleration of the final rendering, flexible graphics hardware is increasingly being used also for the mapping and filtering stages of the visualization pipeline, thus giving rise to new levels of interactivity in visualization applications. The talk will present recent results of applying programmable graphics hardware in various visualization algorithms covering volume data, flow data, terrains, NPR rendering, and distributed and remote applications. [source] Cortical inhibitory circuits in eye-movement generationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2003Peter H. Schiller Abstract The role inhibitory circuits play in target selection with saccadic eye movements was examined in area V1, the frontal eye fields (FEF) and the lateral intraparietal sulcus (LIP) of the Rhesus Macaque monkey by making local infusions of the GABA agonist muscimol and antagonist bicuculline. In V1, both agents greatly interfered with target selection and visual discrimination of stimuli placed into the receptive field of the affected neurons. In the FEF, bicuculline facilitated target selection without affecting visual discrimination and generated many spontaneous saccades. Muscimol in the FEF interfered with saccadic eye-movement generation. In the LIP, bicuculline was ineffective and muscimol had only a small effect. These findings suggest that in the FEF GABAergic inhibitory circuits play a central role in eye-movement generation whereas in V1 these circuits are essential for visual analysis. Inhibitory circuits in the LIP do not appear to play a central role in target selection and in visual discrimination. [source] Taking Television Seriously: A Sound and Image Bite Analysis of Presidential Campaign Coverage, 1992,2004JOURNAL OF COMMUNICATION, Issue 4 2007Erik P. Bucy This study updates and builds on Hallin's landmark investigation of sound-bite news by documenting the prevalence of candidate image bites, where candidates are shown but not heard (as opposed to being shown and heard), in general election news over 4 election cycles. A visual analysis of broadcast network (ABC, CBS, and NBC) news coverage of the 1992, 1996, 2000, and 2004 U.S. presidential elections finds that image bites constituted a greater percentage of total campaign coverage than sound bites, with candidates appearing in image bites significantly more than sound bites. Even as candidate sound bites continue to shrink over time, image-bite time is increasing in duration,and candidates are being presented in image bites almost twice as much as journalists. Sound bites are also found to be largely attack and issue focused. Based on these findings, we call for greater appreciation of visual processing, nonverbal communication, and voter learning from television news in the study of media and politics. Résumé Prendre la télévision au sérieux : Une analyse des clips sonores et visuels de la couverture des campagnes électorales présidentielles, 1992-2004 Cette étude met à jour et raffine l,enquête qu'avait faite Hallin sur les clips sonores d,actualités en documentant la prévalence des clips visuels des candidats, dans lesquels ceux-ci sont montrés mais non entendus (par opposition àêtre montrés et entendus), dans les bulletins d'information sur les élections générales au travers de quatre cycles électoraux. Une analyse visuelle de la couverture par les bulletins d,information des réseaux de télédiffusion (ABC, CBS et NBC) des élections présidentielles américaines de 1992, 1996, 2000 et 2004 démontre que les clips visuels ont constitué un plus grand pourcentage de la couverture électorale totale que les clips sonores, les candidats apparaissant plus fréquemment (de façon significative) dans les clips visuels que dans les clips sonores. Alors que les clips sonores des candidats ne cessent de raccourcir au fil du temps, la durée des clips visuels augmente , et les candidats sont présentés dans des clips visuels dans une proportion presque deux fois plus grande que les journalistes. L'étude démontre également que les clips sonores sont largement centrés sur les attaques et les enjeux. D'après ces résultats, nous réclamons une plus grande compréhension du traitement visuel, de la communication non verbale et de l,apprentissage que font les électeurs à partir des bulletins de nouvelles, dans l'étude des médias et de la politique. Abstract Fernsehen ernst nehmen: Eine Analyse der Sound und Bild Bites der Präsidentschaftskampagnenberichterstattung 1992-2004 Diese Untersuchung basiert auf und erweitert die zentrale Studie von Hallin zu Sound Bite Nachrichten, indem sie über 4 Wahlzyklen hinweg die Verbreitung von Kandidaten Bild Bites dokumentiert. Bild Bites sind dabei Nachrichtenteile, in denen die Kandidaten zwar sichtbar, aber nicht hörbar sind (im Gegensatz zu sichtbar und hörbar). Eine visuelle Analyse der Nachrichtenberichterstattung zu den Präsidentschaftswahlen von 1992, 1996, 2000 und 2004 auf ABC, CBS und NBC zeigte, dass Bild Bites einen größeren Anteil der Kampagnengesamtberichterstattung ausmachen als Sound Bites, und dass die Kandidaten signifikant häufiger in Bild Bites erscheinen als in Sound Bites. Auch wenn die Zahl der Sound Bites der Kandidaten über die Jahre hinweg abnahmen, nehmen die Bild Bites in diesem Zeitraum zu - und Kandidaten werden in Bild Bites fast doppelt so oft gezeigt wie Journalisten. Sound Bites konzentrieren sich inhaltlich außerdem eher auf Angriffe und Themen. Basierend auf diesen Ergebnissen, fordern wir eine Konzentration auf die Untersuchung von visueller Verarbeitung, nonverbaler Kommunikation und dem Aspekt des Lernens von Fernsehnachrichten in der Erforschung von Medien und Politik. Resumen Tomando a la Televisión Seriamente: Un Análisis de los fragmentos de Sonido e Imagen de la Cobertura de Campañas Presidenciales, 1992-2004 Este estudio actualiza y extiende la investigación pionera de Hallin sobre los fragmentos de sonidos de noticias a través de la documentación de la prevalencia de las imágenes fragmentadas de los candidatos, en las cuales los candidatos fueron mostrados pero no escuchados (en vez de ser mostrados y escuchados), en las noticias de las elecciones generales durante 4 ciclos electivos. Un análisis visual de la cobertura de noticias de las redes de televisión (ABC, CBS, y NBC) y de las elecciones presidenciales de los Estados Unidos de 1992, 1996, 2000, y 2004 encontró que los fragmentos de imágenes, más que los de los sonidos, constituían un gran porcentaje de la cobertura total de la campaña, con los candidatos apareciendo más significativamente en los fragmentos de imágenes que en los fragmentos de sonido. Aún cuando los fragmentos de sonidos de los candidatos continúan reduciéndose a través del tiempo, el tiempo del fragmento de la imagen está incrementando en duración-y los candidatos son presentados en fragmentos de imágenes casi dos veces más que los periodistas. Los fragmentos de sonido, en su mayoría, se enfocan en ataques y asuntos. Basados en estos resultados, hacemos un llamado a la apreciación del procesamiento visual, de la comunicación no-verbal, y del aprendizaje del votante por medio de las noticias televisivas en el estudio de los medios y la política. ZhaiYao Yo yak [source] Photoelastic stress analysis in perforated (Rochette) resin bonded bridge designJOURNAL OF ORAL REHABILITATION, Issue 5 2000H. M. Ziada Rochette described the perforated cast metal bonded design for splinting periodontally compromised teeth. The design was later used for replacing missing teeth. The main causes of failure of the perforated (Rochette) type design were attributed to inappropriate case selection and erosion of the composite from perforations. The aim of this study was to analyse the effect of stress magnitude and direction on failure of perforated resin bonded bridges (RBBs). The objective was to compare stress magnitudes in this design with those reported on the non-perforated RBBs. Photoelastic modelling materials were selected to represent the relative stiffnesses of a posterior mandibular and an anterior maxillary perforated (Rochette) type design. The sizes of the models were scaled to ×2·5 in order to enhance visual analysis of the stress patterns. Stress magnitudes were quantified from isochromatic fringes and stress directions were evaluated from stress trajectories. These revealed a high-stress concentration around the perforations, particularly for those at the proximo-lingual/palatal (connector) areas. This experimental study revealed that the main reason for failure of Rochette designs is deformation at the perforations. [source] Electroencephalogram spindle activity during dexmedetomidine sedation and physiological sleepACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2008E. HUUPPONEN Background: Dexmedetomidine, a selective ,2 -adrenoceptor agonist, induces a unique, sleep-like state of sedation. The objective of the present work was to study human electroencephalogram (EEG) sleep spindles during dexmedetomidine sedation and compare them with spindles during normal physiological sleep, to test the hypothesis that dexmedetomidine exerts its effects via normal sleep-promoting pathways. Methods: EEG was continuously recorded from a bipolar frontopolar,laterofrontal derivation with Entropy Module (GE Healthcare) during light and deep dexmedetomidine sedation (target-controlled infusions set at 0.5 and 3.2 ng/ml) in 11 healthy subjects, and during physiological sleep in 10 healthy control subjects. Sleep spindles were visually scored and quantitatively analyzed for density, duration, amplitude (band-pass filtering) and frequency content (matching pursuit approach), and compared between the two groups. Results: In visual analysis, EEG activity during dexmedetomidine sedation was similar to physiological stage 2 (S2) sleep with slight to moderate amount of slow-wave activity and abundant sleep spindle activity. In quantitative EEG analyses, sleep spindles were similar during dexmedetomidine sedation and normal sleep. No statistically significant differences were found in spindle density, amplitude or frequency content, but the spindles during dexmedetomidine sedation had longer duration (mean 1.11 s, SD 0.14 s) than spindles in normal sleep (mean 0.88 s, SD 0.14 s; P=0.0014). Conclusions: Analysis of sleep spindles shows that dexmedetomidine produces a state closely resembling physiological S2 sleep in humans, which gives further support to earlier experimental evidence for activation of normal non-rapid eye movement sleep-promoting pathways by this sedative agent. [source] Intensity-based signal separation algorithm for accurate quantification of clustered centrosomes in tissue sectionsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 12 2006Markus C. Fleisch Abstract Centrosomes are small organelles that organize the mitotic spindle during cell division and are also involved in cell shape and polarity. Within epithelial tumors, such as breast cancer, and some hematological tumors, centrosome abnormalities (CAs) are common, occur early in disease etiology, and correlate with chromosomal instability and disease stage. In situ quantification of CA by optical microscopy is hampered by overlap and clustering of these organelles, which appear as focal structures. CA has been frequently associated with Tp53 status in premalignant lesions and tumors. Here the authors described an approach to accurately quantify centrosome frequencies in tissue sections and tumors, independently of background or noise levels. Applying simple optical rules in nondeconvolved conventional 3D images of stained tissue sections, the authors showed that they could evaluate more accurately and rapidly centrosome frequencies than with traditional investigator-based visual analysis or threshold-based techniques. The resulting population-based frequency of centrosomes per nucleus could then be used to approximate the proportion of cells with CA in that same population. This was done by taking into account baseline centrosome amplification and proliferation rates measured in the tissue. Using this technique, the authors showed that 20,30% of cells have amplified centrosomes in Tp53 null mammary tumors. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source] Fully automated analysis of colonic manometry recordingsNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2002A. M. P. De Schryver AbstractThe purpose of this study was to develop a computer program for fully automated analysis of all presently known motor patterns in human colonic motility recordings. Colonic pressure recordings obtained from 24 healthy volunteers were used. Algorithms were developed for the detection and numerical analysis of five types of pressure waves: antegrade, retrograde, simultaneous, high-amplitude and isolated pressure waves. Furthermore, periodical motor activity was quantified. Validation was performed by comparison with visual analysis by two experienced observers. Patterns recorded during day- and night-time were compared using multiple-factor analysis of variance with Bonferroni correction. Automated analysis correlated well with visual peak detection (r = 0.98, P <0.01) and detection of antegrade pressure waves (r = 0.98, P <0.01). Most motor patterns showed a diurnal variation. During the night, prevalences of antegrade (938 vs 455; P <0.05), retrograde (112 vs 81; P <0.05), high-amplitude (12.9 vs 1.3; P <0.05), isolated pressure waves (1114 vs 765; P <0.05), and periodic motor activity were decreased (7.33 vs 4.47%; P <0.05). However, when expressed as percentage of absolute numbers of pressure waves, prevalences remained constant. In conclusion, fully automated analysis of all hitherto described colonic motility patterns is feasible. During the night, overall wave prevalences markedly decreased, but the distribution over the various motor patterns was preserved. [source] Evaluating the efficacy of tele-cognitive rehabilitation for functional performance in three case studiesOCCUPATIONAL THERAPY INTERNATIONAL, Issue 1 2003Dr Sing-Fai Tam PhD Associate Professor Abstract Traumatic brain injury (TBI) is one of the main causes of long-term disability, and its rehabilitation is a challenge to the healthcare team. Tele-rehabilitation, through using advancements in networking and tailor-made software, has been developed and applied to the cognitive rehabilitation of persons with brain injury in the present study. Tele-cognitive rehabilitation uses customized online computer software as a treatment mode. The online treatment software is operated on an interactive tele-communication platform , for example, video conferencing with screen sharing. Through implementing the tele-cognitive rehabilitation activities, therapists can help clients to practise and thus improve their cognitive skills through using the treatment software successfully. Moreover, hypermedia programming techniques allow the therapist to adjust the software to meet the client's treatment needs, so that the treatment is appropriate to his/her functional levels and living environment. Also the software can customize immediate visual, auditory and personalized feedback to motivate the client and training can be set at the right pace for the client's needs. The present study aimed to evaluate the effectiveness and perceived efficacy of the newly developed customized tele-cognitive rehabilitation programme for three subjects with traumatic brain injury through using single-case and qualitative research design. The cognitive factors investigated in this pilot study were, respectively, Chinese word recognition, prospective memory and semantic memory. The subjects had undergone a recruitment process with stipulated screening criteria. A single case experimental design (ABA reversal/withdrawal design) consisted of a no-intervention baseline phase (A), an intervention phase (B) and a no-intervention withdrawal phase (A). There were six sessions in each phase, making a total of 18 sessions. Tele-cognitive rehabilitation software was tailor-made according to each subject's cognitive functional needs. To monitor the change in cognitive functions, variables were tapped by tailor-made assessment and qualitative questionnaires through interviews, and they were then used to explore subjects' opinions of the programme and to test the treatment efficacy of the tele-cognitive rehabilitation programme. Finally, the relationships among the three phases were analysed through visual analysis and trend line analysis by means of the split-middle method. The three persons with brain injury showed improving trends and levels of specific cognitive performance during the treatment phase. Qualitative findings were analysed and confirmed the efficacy of the treatment module. The tele-cognitive rehabilitation approach was well received by subjects. The authors suggest that further replication studies of this kind should be conducted in the future and that more subjects should be recruited to improve the generalizability of the results. Copyright © 2003 Whurr Publishers Ltd. [source] Muscle magnetic resonance imaging involvement in muscular dystrophies with rigidity of the spineANNALS OF NEUROLOGY, Issue 2 2010Eugenio Mercuri MD Objective The aim of the study was to evaluate whether the visual analysis of muscle magnetic resonance imaging scans can identify specific patterns of muscle involvement. Methods We assessed scans from 83 patients with muscle disorders characterized by rigidity of the spine secondary to mutations in 4 different genes. The conditions studied were rigid spine syndrome (SEPN1 defects), Bethlem myopathy, and Ullrich congenital muscular dystrophy, allelic disorders caused by Col6A1, Col6A2, and Col6A3 mutations, the autosomal dominant form of Emery,Dreifuss muscular dystrophy (LMNA defects) and calpain-deficient limb girdle muscular dystrophy (CAPN3 defects). The scans of 25 patients affected by other myopathies were also reviewed as a control group. The scans were compared with the previously described patterns. Results In 82% of the scans in the study group (68/83) the patterns were classified as "typical" of 1 of the 5 forms studied, and in 7 (8%) were consistent with 1 of the reported patterns but not entirely typical. With one exception, the patterns identified were always consistent with the appropriate genetic diagnosis. The remaining scans (9%) had only minimal changes and were uninformative. None of the scans of the 25 patients in the control group had patterns that could be classified as typical of the 5 forms examined. The sensitivity to detect selective patterns in relation to the genetic diagnosis was 0.9. Interpretation These findings suggest that muscle magnetic resonance imaging could be used in clinical practice as an additional tool in the differential diagnosis of muscle disorders with prominent spinal rigidity. ANN NEUROL 2010;67:201,208 [source] Paraconsistent Artificial Neural Network as Auxiliary in Cephalometric DiagnosisARTIFICIAL ORGANS, Issue 7 2010Mauricio C. Mario Abstract This work presents an application of the paraconsistent artificial neural network (PANN) in the analysis of cephalometric variables and provides an orthodontic diagnosis. An expert's analysis is subject to the inherent imprecision of measurements, registers, and individual variability of physician visual analysis. Patient input cephalometric values are compared with means drawn from individuals considered normal in the cephalometric point of view by the PANN. This reference is constituted by individuals from 6 to 18 years old, both genders. The applied cephalometric analysis was targeted to measure skeletal and dental discrepancies and established a cephalometric diagnosis. The analysis results in degrees of skeletal, anteroposterior, and dental discrepancy, pertinent to upper and lower incisors. A sample of 120 orthodontic patients was processed by the proposed model and three orthodontic experts. Comparisons between the model and the human expert's performance provided kappa indexes that varied from moderate to almost perfect agreement. The agreement between the model and specialist's performance was equivalent. In addition, the model pointed out contradictions presented in the data that were not noticed by the orthodontists, which highlight the contribution that this kind of system could carry out in the orthodontics decision support. [source] Diagnostic performance of cardiac magnetic resonance imaging in coronary artery diseaseCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 2 2010Jussi P. Pärkkä Summary Background:, Cardiac magnetic resonance imaging (CMR) is a promising method for detecting coronary artery disease (CAD). The first reports of new diagnostic techniques indicated generally unrealistic diagnostic performance relying on retrospectively observed cut-off values of quantitative parameters. Although visual analysis of CMR is the most applicable method for clinical work, its diagnostic performance is not fully elucidated for study components such as wall motion, perfusion and late enhancement in patients with different severity of CAD. Methods:, A total of 30 subjects including 20 patients with CAD and 10 healthy volunteers were selected for the study. Of the patients, ten had stable CAD, five confirmed myocardial infarction (MI) without Q-waves in electrocardiogram (ECG) and five confirmed MI with Q-waves in ECG. All patients underwent coronary angiography and CMR for evaluating resting wall motion, rest and stress perfusion and late enhancement. Results:, Combining the data from the three CMR techniques, 12 out of 20 patients were correctly identified as having CAD, and all controls were found to be healthy. Sensitivity, specificity, accuracy, positive and negative predictive values were 60·0%, 100·0%, 73·0%, 100·0% and 55·6%, respectively. Of the CMR components, resting wall motion and late enhancement gave the most diagnostic yield. Conclusions:, We conclude that evaluation of CAD is feasible in patients with different severity of CAD using visually analysed CMR, especially when available CMR methodologies are combined together. [source] Validation of a new automated method for analysis of gated-SPECT imagesCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 3 2006Milan Lomsky Summary We recently presented a new method for quantification of CArdiac FUnction , denoted CAFU , as the first step in the development of an automated method for integrated interpretation of gated myocardial perfusion single photon emission computed tomography (SPECT) images. The aim of this study was to validate CAFU in the assessment of global and regional function of the left ventricle. Quantitative gated-SPECT (QGS), the most widely used software package for quantification of gated-SPECT images, was used as reference method for the measurements of ejection fraction (EF) and ventricular volumes, and visual analysis by an experienced physician was used as reference method for the measurements of regional wall motion and thickening. Two different groups of consecutive patients referred for myocardial perfusion scintigraphy were studied. Global function was evaluated in 316 patients and regional function in 49 other patients. The studies were performed using a 2-day stress/rest 99 m-Tc-sestamibi protocol. A good correlation was found between EF values from QGS and CAFU (EF CAFU = 0·84 EF QGS + 13, r = 0·94), but CAFU values were on average 4 EF points higher than QGS values. With CAFU the segments with normal thickening according to the physician showed significantly higher thickening values (in all parts of the myocardium) compared to the segments classified as having abnormal thickening. In conclusion, this study demonstrates that CAFU can be used to quantify global and regional function in gated-SPECT images. This is an important step in our development of an automated method for integrated interpretation of gated-SPECT myocardial perfusion scintigraphy studies. [source] | |||||||||||||