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The Low-dose Limits of Lung Nodule Detectability in Volumetric Computed TomographySilverman, Jordan 15 February 2010 (has links)
Purpose. Low-dose computed tomography is an important imaging modality for screening and surveillance of lung cancer. The goal of this study was to determine the extent to which dose could be minimized while maintaining diagnostic accuracy through knowledgeable selection of reconstruction techniques.
Methods. An anthropomorphic phantom was imaged on a 320-slice volumetric CT scanner. Detectability of small solid lung nodules was evaluated as a function of dose, patient size, reconstruction filter and slice thickness by means of 9-alternative forced-choice observer tests.
Results. Nodule detectability decreased sharply below a threshold dose level due to increased image noise. For large body habitus, optimal (smooth) filter selection reduced dose by a factor of ~3. Nodule detectability decreased for slice thicknesses larger than the nodule diameter.
Conclusions. Radiation dose can be reduced well below current clinical protocols. Smooth reconstruction filters and avoidance of large slice thickness permits lower-dose techniques without tradeoff in diagnostic performance.
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CT-based measurement of lung volume and attenuation of deceasedSylvan, Elin January 2005 (has links)
Because of the difficulties in concluding whether a person has drowned or not, information that could be relevant for postmortal diagnosis of drowning was studied. With postmortal CT images lung volume, mean attenuation, anterior-posterior difference, lung density profile and amount of water within the lungs were investigated. The report also evaluates three examples of software that calculates lung volume from postmortal CT images: Siemens’ Syngo Pulmo CT, Siemens‘ Volume Evaluation and GE Medical Systems’ Volume Viewer. The method used at autopsy was also studied. The repeatability and validity were tested and sources of errors identified. Repeatability and validity for the three tested types of software were acceptable, while the method used at autopsy had to be improved. The study also showed that lung volume related to length, anterior-posterior difference and lung density profile seemed to vary between drowned and other deceased. These measures might conclude whether a person has drowned.
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Correlation of lung collapse and gas exchangeWolf, Samuel J., Reske, Alexander P., Hammermüller, Sören, Costa, Eduardo L.V., Spieth, Peter M., Hepp, Pierre, Carvalho, Alysson R., Kraßler, Jens, Wrigge, Hermann, Amato, Marcelo B. P., Reske, Andreas W. 11 August 2015 (has links) (PDF)
Background: Atelectasis can provoke pulmonary and non-pulmonary complications after general anaesthesia. Unfortunately, there is no instrument to estimate atelectasis and prompt changes of mechanical ventilation during general anaesthesia. Although arterial partial pressure of oxygen (PaO2) and intrapulmonary shunt have both been suggested to correlate with atelectasis, studies yielded inconsistent results. Therefore, we investigated these correlations.
Methods: Shunt, PaO2 and atelectasis were measured in 11 sheep and 23 pigs with otherwise normal lungs. In pigs, contrasting measurements were available 12 hours after induction of acute
respiratory distress syndrome (ARDS). Atelectasis was calculated by computed tomography relative to total lung mass (Mtotal). We logarithmically transformed PaO2 (lnPaO2) to linearize its relationships with shunt and atelectasis. Data are given as median (interquartile range).
Results: Mtotal was 768 (715–884) g in sheep and 543 (503–583) g in pigs. Atelectasis was 26 (16–47)% in sheep and 18 (13–23) % in pigs. PaO2 (FiO2 = 1.0) was 242 (106–414) mmHg in sheep and 480 (437–514) mmHg in pigs. Shunt was 39 (29–51)% in sheep and 15 (11–20) % in pigs. Atelectasis correlated closely with lnPaO2 (R2 = 0.78) and shunt (R2 = 0.79) in sheep (P-values<0.0001). The correlation of atelectasis with lnPaO2 (R2 = 0.63) and shunt
(R2 = 0.34) was weaker in pigs, but R2 increased to 0.71 for lnPaO2 and 0.72 for shunt 12 hours after induction of ARDS. In both, sheep and pigs, changes in atelectasis correlated strongly with corresponding changes in lnPaO2 and shunt. Discussion and Conclusion: In lung-healthy sheep, atelectasis correlates closely with lnPaO2 and shunt, when blood gases are measured during ventilation with pure oxygen. In lung-healthy pigs, these correlations were significantly weaker, likely because pigs have stronger hypoxic pulmonary vasoconstriction (HPV) than sheep and humans. Nevertheless, correlations improved also in pigs after blunting of HPV during ARDS. In humans, the observed relationships may aid in
assessing anaesthesia-related atelectasis.
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Validation of the 60-second chair rise as a measure of physical function in patients with non-small cell lung cancerPereira, Lucy. January 2008 (has links)
Yearly, 22, 200 Canadians are diagnosed with lung cancer, with 80-85% of the cases being non-small cell lung cancer (NSCLC). With diagnoses being predominantly in the advanced stages, prognosis is poor and quality of life (QoL) becomes the focus of treatment. The main symptom cachexia, issues a loss of strength and impacts on an important aspect of QoL, physical function. Physical function is predominately assessed subjectively. Lately performance-based measures are gaining in popularity. One performance measure, the chair rise test, has not been validated in the NSCLC population and was the objective of this study. / Subjects completed the chair rise test, 6MWT, hand grip, and the SF-36 pre and post chemotherapy. Evidence for construct and discriminant validity but not predictive validity was provided for the chair rise test. The 60-second chair rise may be too strenuous for persons with severe disability but a standardized timed-based chair rise test is needed.
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Towards understanding patients' and caregivers' assessments of symptoms and quality of life in lung cancer /Broberger, Eva, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.
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Radiological imaging of pulmonary emphysema : preoperative evaluation of candidates for lung volume reduction surgery /Cederlund, Kerstin, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.
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Nitric oxide generation from nitroglycerin and other no-donors measured in the lung and studies on nitrate tolerance in the cardiovascular system /Agvald, Per, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.
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Apoptotic signaling in lung carcinoma cells with focus on mechanisms of radioresistance /Ekedahl, Jessica, January 2003 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.
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C/EBP transcription factors in lung cellular differentiation and development /Berg, Tove, January 2005 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.
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Nitric oxide and eicosanoids : significance and interactions during antigen-induced responses in peripheral lung tissue /Larsson, Anna-Karin, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.
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