Lung nodule volumetry is used to diagnose the likelihood of malignancy in nodules detected during thoracic CT scans. These measurements are unreliable when the patient is subject to respiratory motion. We seek to understand the relationship between reconstructed images and the actual size of nodules subject to motion induced by quiet breathing. CT images of solid spheres of varying size and composition were acquired while travelling through a known path to approximate the motion of a pulmonary nodule during respiration. The measured size of the sphere’s image was found to increase non-linearly with speed. However, these relationships were dependent on the CT number of the sphere and the reconstruction filter used to generate the image. From these results we expect that for a specific CT number we can estimate the size of an object from a CT image if the speed of the object at the time of the scan is known.

Lung nodule volumetry is used to diagnose the likelihood of malignancy in nodules detected during thoracic CT scans. These measurements are unreliable when the patient is subject to respiratory motion. We seek to understand the relationship between reconstructed images and the actual size of nodules subject to motion induced by quiet breathing. CT images of solid spheres of varying size and composition were acquired while travelling through a known path to approximate the motion of a pulmonary nodule during respiration. The measured size of the sphere’s image was found to increase non-linearly with speed. However, these relationships were dependent on the CT number of the sphere and the reconstruction filter used to generate the image. From these results we expect that for a specific CT number we can estimate the size of an object from a CT image if the speed of the object at the time of the scan is known.

Determining the most efficient use of diagnostic tests is one of the complex issues facing the medical practitioners. It is generally accepted that excessive use of tests is common practice in medical diagnosis. Many tests are performed even though the incremental knowledge gained does not affect the course of diagnosis. With the soaring cost of healthcare in the US, there is a critical need for cutting costs of diagnostic tests, while achieving a higher level of diagnostic accuracy. Various decision making tools assisting physicians in diagnosis management have been presented to the literature. One such method, called analytical hierarchy process, utilize a multilevel structure of decision criterion for sequential pair wise comparison of available test choices. Many of the decision-analytic methods are based on Bayes' theory and decision trees. These methods use threshold treatment probabilities and performance characteristics of the tests, such as true-positive rate and false-positive rates, to choose among the available alternatives. Sequential testing approaches tend to elongate the diagnosis process, whereas the parallel testing approach generally involves higher number of tests. This research is focused on developing a machine learning based methodology for finding an efficient testing strategy for medical diagnosis. The method, based on the patient parameters (both observed and tested), recommends test(s) with the objective of optimizing a measure of performance for the diagnosis process. The performance measure is a combined cost of the testing, the risk and discomfort associated with the tests and the time taken to reach diagnosis. The performance measure also considers the diagnostic ability of the tests. The methodology is developed combining tools from the fields of data mining (rough set theory, in particular), utility theory, Markov decision processes (MDP), and reinforcement learning (RL). The rough set theory is used in extracting diagnostic information in the form of rules from the medical databases. Utility theory is used to bring three non-homogenous measures (cost of testing, risk and discomfort and diagnostic ability) into one cost based measure of performance. The MDP framework along with an RL algorithm facilitates obtaining efficient testing strategies. The methodology is implemented on a sample problem of diagnosing Solitary Pulmonary Nodule (SPN). The results obtained are compared with those from four other approaches. It is shown that the RL based methodology holds significant promise in improving the performance of diagnostic process.

No description available.

Cardiac arrest due to air embolism is an infrequent complication. Air embolism can be associated with procedures like endoscopic retrograde cholangiopancreatography, endoscopic variceal ligation, operative hysteroscopy, laparoscopic surgery, pacemaker placement, cardiac ablation, fiberoptic bronchoscopy, and decompression sickness. In rare cases, air embolus can be a catastrophic complication of computed tomography (CT) guided lung biopsy, which can lead to cardiac arrest. We present a case of a 67-year-old male chronic smoker with a left lower lobe pulmonary nodule who had a cardiac arrest due to air embolism as a consequence of CT guided biopsy of the pulmonary nodule found on a CT scan of the chest. He was successfully resuscitated and intubated for mechanical ventilation. He was managed conservatively and discharged home in a stable condition.

Lung cancer is the leading cause of cancer death in the United States. While low-dose computed tomography (CT) screening reduces lung cancer mortality by 20%, 97% of suspicious lesions are found to be benign upon further investigation. Computer-aided diagnosis (CAD) tools can improve the accuracy of CT screening, however, current CAD tools which focus on imaging characteristics of the nodule alone are challenged by the limited data captured in small, early identified nodules. We hypothesize a CAD tool that incorporates quantitative CT features from the surrounding lung parenchyma will improve the ability of a CAD tool to determine the malignancy of a pulmonary nodule over a CAD tool that relies solely on nodule features. Using a higher resolution research cohort and a retrospective clinical cohort, two CAD tools were developed with different intentions. The research-driven CAD tool incorporated nodule, surrounding parenchyma, and global lung measurements. Performance was improved with the inclusion of parenchyma and global features to 95.6%, compared to 90.2% when only nodule features were used. The clinically-oriented CAD tool incorporated nodule and parenchyma features and clinical risk factors and identified several features robust to CT variability, resulting in an accuracy of 71%. This study supports our hypothesis that the inclusion of parenchymal features in the developed CAD tools resulted in improved performance compared to the CAD tool constructed solely with nodule features. Additionally, we identified the optimal amount of lung parenchyma for feature extraction and explored the potential of the CAD tools in a clinical setting.

In der Studie wurde die Drahtmarkierung als Operationshilfsmethode vor der VATSvideo- assistierten Thorakoskopie bei der Abklärung von solitären pulmonalen Rundherden untersucht. Mit dieser Methode konnte der Lungenherd exakt markiert und transthorakal fixiert werden. Intraoperativ wurde der am Draht hängende Herd mit dosierter Kraft nach außen gezogen, endoskopisch verifiziert und komplikationslos entfernt. Bei der Drahtmarkierung wurden drei verschiedene Drähte benutzt, der größte Teil der Markierungen wurde mit dem Somatex-Lokalisationsset 18 G (84) Spiraldraht durchgeführt. Bei 3 Patienten wurde ein minimaler Pneumothorax, bei 5 Patienten eine geringe Einblutung und bei 2 Patienten ein großer Pneumothorax (>1 cm) und bei 3 Patienten beide Komplikationen festgestellt. Bei keinem Patienten war eine Dislokalisation des Drahtes aufgetreten. Chirurgen und Radiologen teilen die Meinung, dass der Spiraldraht patientenkomfortabel, treffsicher anwendbar und zukunftsträchtig ist. Die kombinierte Anwendung von Herdfixation mittels Spiraldraht und videothorakoskopischer Entfernung von Lungenherden ist für pleuraferne und daher oberflächlich nicht sichtbare Lungenherde empfehlenswert. / With the increasing use of multi-slice computed tomography (MSCT) pulmonary nodules are more often detected. The propose of our study was to evaluate use of the computed tomography guided spiral-wire localization before video-assisted thoracoscopic surgery (VATS). 54 patients with pulmonary nodules underwent ct-guided application of a spiralwire lung localization-set (Somatom, Berlin, Germany). The average age was 58 years, the mean distance between the nodule and the visceral pleura was 7,9 mm and the mean diameter was 13,1 mm. Following this procedure, the patients underwent a VATS resection. In all patients the placement of the spiral-wire was succesful without any dislocation. The major complications were: Asymtomatic pneumothorax, local bleeding and in 3 patients a combination of local bleeding and a minor pneumothorax. In conclusion wire localization of peripheral pulmonary nodules is a safe and effective procedure to assist VATS resection.

Introduction : L'installation de caméras de Tomographie à Emission de Positons (TEP) a eu lieu en 2003 dans l'inter région Grand-Est de la France. Plusieurs études ont montré ses performances diagnostiques et ses bénéfices en évitant: des interventions de chirurgie exploratrice devenue inutile (thoracotomie aux séquelles douloureuses, laparotomie exploratrice), et certains examens complémentaires d'imagerie ou d'exploration fonctionnelle inutile. Objectifs : 1) évaluer le changement des stratégies diagnostiques du Nodule Pulmonaire Isolé (NPI) et du Cancer du Poumon Non à Petites Cellules (CPNPC) induit par l'implantation de la TEP dans l'inter - région Grand - Est de la France ; 2) mesurer l'impact du changement sur la qualité de vie des patients atteints d'un NPI et d'un CPNPC ; et 3) étudier le rôle pronostique de la QV sur la survie des patients atteint d'un CPNPC.Méthodes : Etude prospective multicentrique constituant 2 cohortes « Avant (2001 - 2002) » et « Après (2004 - 2005) » de l'implantation de la TEP. Ont été recueillis : les caractéristiques sociodémographiques des patients, clinique du NPI et du CPNPC, les examens diagnostiques et traitements réalisés jusqu'à 6 mois après la fin du bilan. Deux auto-questionnaires de QV (SF36 et QLQ C-30) ont été distribués à 3 et 6 mois après la fin du bilan diagnostique.Résultats : 1) Nous avons observé une diminution du nombre d'examens réalisés au cours du bilan diagnostique d'un NPI de 4 examens en phase avant à 3 en moyenne en phase après. Néanmoins, la fréquence des examens invasifs jugés évitables a posteriori pratiqués chez les patients ayant un NPI bénin n'était pas différente (47% phase avant versus 49% phase après). Un an après son installation, la TEP a été utilisée chez 11% des patients. 2) Les patients atteints d'un NPI et quelque soit sa nature, maligne ou bénigne, ont eu un score moyen de QV plus bas (-8 à -32 points, p<0.001) que celui mesuré dans la population générale française indépendamment du sexe et de l'âge. Les scores QV des patients ayant un NPI bénin se révélaient être statistiquement plus élevés que ceux des patients ayant un NPI malin, notamment dans les dimensions « fonctionnement social », « rôle physique » et « rôle émotionnel » (+10, +14 et +18 points respectivement, p=0,02 à 0,04).3) Les bons scores en fonctionnement physique en SF-36 (HR=0.78 ; IC=0.68 - 0.90 ; p<0.001), et en la limitation due à l?état physique en QLQ-C30 (HR=0.53 ; IC=0.59 - 0.89 ; p=0.003) indiquant une bonne perception des patients sur leurs fonctionnement physique sont liés à une meilleure survie. Les symptômes élevés de constipation (HR=1.18 ; IC=1.005-1.38 ; p=0.04) en QLQ-C30, par contre, est lié à une mauvaise survie. Le sexe féminin est lié à une meilleure survie (HR=0.55 ; IC=0,33 - 0,94 ; p=0,04). Cependant, le stade III et IV du CPNPC est associé à une mauvaise probabilité de survie (HR=1,72 ; IC=1,16 - 2,57 ; p=0,007).Discussion/conclusion : Les stratégies diagnostiques du NPI ont changé. L'impact de cette maladie, mesuré de façon subjective par la qualité de vie (QV) des patients peut indiquer certains domaines essentiels à améliorer dans sa prise en charge car une meilleure QV en oncologie broncho-pulmonaire est associée à une meilleure survie / Background: The Positron Emission Tomography was installed in 2003 in the North-eastern region of France. Previous studies showed its diagnostic performance and its benefices in avoiding: surgical exploratory interventions proved to be unnecessary a posteriori (for example, thoracotomy or laparotomy with painful consequences), and certain complementary imaging tests or unnecessary functional explorations. Objectives : 1) to evaluate changes in diagnostic strategies of Solitary Pulmonary Nodule (SPN) and Non Small Cell Lung Cancer (NSCLC) induced by the implantation of PET in the Northeastern region of France ; 2) to mesure the impact of these changes on the health related quality of life (HRQoL) of patients with SPN and NSCLC; and 3) to study the prognostic role of the HRQoL on the survival of patients with NSCLC.Methodes: An observational, prospective, multi-center design was applied. Two cohorts « Before (2001 - 2002) - After (2004 - 2005) » the PET implantation in the regions were settled up. Data collected included: patients' socio-demographic and clinical characteristics, the diagnostic tests and then treatments that were carried out during 6 months after the end of the diagnostic process. Two HRQoL questionnaires (the generic questionnaire SF-36 and the cancer specific one QLQ-C30) were distributed at 3 and 6 months after the end of the diagnostic process.Results:1) The number of diagnostic tests of patients with SPN decreased significantly from a mean of 4 in the before-PET to 3 tests in the after-PET period. Meanwhile, there was not any difference of the frequency of invasive tests considered unnecessary aposteriori for patients with benign SPN (47% before-PET versus 49% after-PET period). One year after its installation, the PET was used in 11 % of diagnostic strategies. In 7.7% of cases it was used after the bronchoscopy. 2) A comparison of the QoL with that of the French general population revealed that patients with SPN, whatever the diagnosis, benign or malignant, had worse mean scores (-8 to -32 points, p<0.001) compared to the general population with similar age and sex. A difference of 24, 30 and 32 points were observed in the "physical functioning", "emotional role" and "physical role" (p<0.001). The scores of patients with benign nodule were higher than those of malignant, especially on "social functioning", "physical role", and "emotional role" (+10, +14 and +18 points respectively, p=0.02 to 0.04). 3) Good scores on "physical functioning" of SF-36 (HR=0.78; CI=0.68 - 0.90; p<0.001) as well as "role functioning" of QLQ-C30 (HR=0.53; CI=0.59 - 0.89; p=0.003) were related to a better survival. Higher symptoms of constipation (HR=1.18; CI=1.005-1.38; p=0.04) in QLQ-C30 were associated to a worse one. While being a woman was associated to a better survival (HR=0.55 ; CI=0,33 - 0,94 ; p=0,04), the stage III and IV of the NSCLC was related to a lower one (HR=1,72 ; CI=1,16 ? 2,57 ; p=0,007) .Conclusion: The diagnostic strategies of SPN changed after PET was available for medical practice. This study showed the negative impact of SPN to patients' HRQoL. It indicates the domains in which health practitioners could interfere in order to improve the management of these diseases, because this study confirmed previous studies in pulmonary oncology, that patients' QoL is related to the survival

Made available in DSpace on 2016-08-17T14:53:20Z (GMT). No. of bitstreams: 1 dissertacao Leonardo.pdf: 864322 bytes, checksum: 557c6817aff39c2f398ebe22a59ad5c6 (MD5) Previous issue date: 2012-04-20 / FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO / Lung cancer is still the leading cause of cancer mortality worldwide, with one of the lowest survival rates after diagnosis. Therefore, early detection is important to increase the chances of curing the patient. The diagnosis is more accurate if the specialist has more information. In view of the above, this work presents a methodology for characterization about the malignancy or benignity of pulmonary nodules, acting as a second opinion for the expert. The methodology was applied in two different databases, one with 73 nodes, 26 malignant and 47 benign, and other with 1034 nodes and 517 malignant and 517 benign. The Diversity Indices of Shannon and Simpson were used as texture descriptors. The features generated were then subjected to the step of feature selection using the stepwise Discriminant Analysis. After this stage, they were classified by the Support Vector Machine (SVM) where we obtained sensitivity of 85.64%, specificity of 97.89% and accuracy of 92.78%. / O câncer de pulmão é ainda a maior causa de mortalidade por câncer em todo mundo, com uma das menores taxas de sobrevida a partir do diagnóstico. Por isso, sua detecção precoce é importante para aumentar a chances de cura do paciente, e de quanto mais informações o médico dispuser, mais preciso será o diagnóstico. Diante do exposto, o presente trabalho apresenta uma metodologia de caracterização de nódulos pulmonares, objetivando se tornar uma ferramenta computacional utilizada para sugerir sobre a malignidade ou benignidade dos mesmos, atuando como uma segunda opinião junto ao especialista. A metodologia foi aplicada em duas bases de dados diferentes, uma com 73 nódulos, sendo 26 malignos e 47 benignos, e outra com 1034 nódulos sendo 517 malignos e 517 benignos. Os Índices de Diversidade de Shannon e de Simpson foram utilizados como descritores de textura. As características geradas foram submetidas à etapa de seleção de características com a utilização da Análise Discriminante stepwise. Após essa etapa foi realizada a classificação pela Máquina de Vetores de Suporte (MVS) onde foram obtidas taxas de sensibilidade de 85,64%, especificidade de 97,89% e acurácia de 92,78%.

In einer initialen Studie verglichen wir das XQi Revolution, welches auf indirektem CsI (Cäsium Iodit) /a: Si (amorphes Silizium) basiert mit einem direkten Digitalröntgengerät a: SE (amorphes Selen) an einem CDRAD-Phantom bei vier unterschiedlichen Eintrittsdosen und an einem TRG-Phantom bei zwei unterschiedlichen Eintrittsdosen. Mittels des berechneten Bildqualitätsfaktors des CDRAD-Phantoms konnten wir zeigen, daß das indirekte im Vergleich zum direkten System bei niedrigeren Dosen eine bessere Detailerkennungsrate aufweist. Ein positiver Trend läßt sich auch beim TRG-Phantom darstellen. In einer weiteren Studie untersuchten wir anhand von Patientenbildern die Bildqualität des Dual Energy Systems bei zwei unterschiedlichen Dosisniveaus, der Standarddosis sowie einer doppelten Dosis, was einem Speed-Äquivalent von 400/1000 bzw. 200/500 entspricht. Bei hoher Dosis konnten wir eine signifikante Reduktion des Rauschens im Knochen- und Weichteilbild feststellen, gleichzeitig nahmen die Störungen durch Bewegungsartefakte signifikant zu. Im Anschluß verglichen wir die Erkennbarkeit verkalkter Lungenpathologien im Standard P/A Bild mit zusätzlichem Einsatz von Dual Energy. Als Goldstandard erfolgte der sichere Nachweis der Pathologien im CT. Bei zusätzlichem Einsatz von Dual Energy konnten wir eine signifikante Steigerung der Sensitivität erkennen. Dieses Ergebnis wurde durch den Qualitätsfaktor, der die Bildeigenschaften kumulativ beschreibt, bestätigt. Weiterhin untersuchten wir analog die Erkennbarkeit von nichtverkalkten Lungenrundherden. Auch bei diesen Pathologien ließ sich ein positiver Trend der Sensitivität und Spezifität bei zusätzlichem Einsatz von Dual Energy erkennen. Zusätzlich stieg die durchschnittliche Entscheidungssicherheit der Gutachter signifikant an. Damit bietet die Dual Energy Subtraktionstechnik eine wertvolle Ergänzung in der Diagnostik verkalkter und nichtverkalkter Lungenpathologien eine wertvolle Ergänzung zum Standardröntgen. / First study assess and quantify the image quality at two dose levels for an amorphous Silicon (a:Si) Cesium Iodide (CsI) flat panel system compared with a direct amorphous Selenium (a:Se) digital radiography system. Image quality of a:Si flat panel digital radiography proved to be superior to a:Se drum digital radiography using low-dose settings. Second study assess the image quality of subtracted soft tissue and bone images of a CsIdetector-based dual-energy system for chest radiography at varying dose levels. Radiation dose did not significantly influence the perception of dual-energy image quality. Next study assess the value of dual-energy chest radiography obtained using a cesium iodide flat-panel detector in addition to standard posteroanterior chest radiography for the detection of calcified chest abnormalities. When dual-energy images were added, sensitivity increased significantly. Brunner and Langer’s test revealed a highly significant difference between posteroanterior chest radiography and dual-energy imaging in the detection of calcified chest abnormalities. Dual-energy images added to standard posteroanterior chest radiographs significantly improve the detection of calcified chest lesions. Last study compare the sensitivity and specificity of digital chest radiography alone with digital chest radiography combined with dual-energy chest radiography in the detection of small non-calcified pulmonary nodules. Standard and dual-energy radiographs were obtained with a flat-panel digital chest system. The increase of nodule detection overall as well as for different size categories was significant. The increase of the confidence level rating was also significant. Dual energy added to standard posteroanterior chest radiography significantly improves the sensitivity, specificity, and confidence in detection of small non-calcified pulmonary nodules. Dual-energy subtraction has the potential to become a future routine application in chest radiography.