Inter‐ and intra‐software reproducibility of computed tomography lung density measurements

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156221/2/mp14130.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156221/1/mp14130_am.pd

Relationship between diffusion capacity and small airway abnormality in COPDGene.

Impaired single breath carbon monoxide diffusing capacity (DLCO) is associated with emphysema. Small airways disease (SAD) may be a precursor lesion to emphysema, but the relationship between SAD and DLCO is undescribed. We hypothesized that in mild COPD, functional SAD (fSAD) defined by computed tomography (CT) and Parametric Response Mapping methodology would correlate with impaired DLCO. Using data from ever-smokers in the COPDGene cohort, we established that fSAD correlated significantly with lower DLCO among both non-obstructed and GOLD 1-2 subjects. The relationship between DLCO with CT-defined emphysema was present in all GOLD stages, but most prominent in severe disease. TRIAL REGISTRATION: NCT00608764. Registry: COPDGene. Registered 06 February 2008, retrospectively registered

Validation of a Robust Method for Quantification of Three-Dimensional Growth of the Thoracic Aorta Using Deformable Image Registration

Purpose: Accurate assessment of thoracic aortic aneurysm (TAA) growth is important for appropriate clinical management. Maximal aortic diameter is the primary metric that is used to assess growth, but it suffers from substantial measurement variability. A recently proposed technique, termed Vascular Deformation Mapping (VDM), is able to quantify three-dimensional aortic growth using clinical computed tomography angiography (CTA) data using an approach based on deformable image registration (DIR). However, the accuracy and robustness of VDM remains undefined given the lack of a ground truth from clinical CTA data, and furthermore the performance of VDM relative to standard manual diameter measurements is unknown. Methods: To evaluate the performance of the VDM pipeline for quantifying aortic growth we developed a novel and systematic evaluation process to generate 31 unique synthetic CTA growth phantoms with variable degrees and locations of aortic wall deformation. Aortic deformation was quantified using two metrics: Area Ratio (AR), defined as the ratio of surface area in triangular mesh elements, and the magnitude of deformation in the normal direction (DiN) relative to the aortic surface. Using these phantoms, we further investigated the effects on VDM’s measurement accuracy resulting from factors that influence quality of clinical CTA data such as respiratory translations, slice thickness and image noise. Lastly, we compare the measurement error of VDM TAA growth assessments against two expert raters performing standard diameter measurements of synthetic phantom images. Results: Across our population of 31 synthetic growth phantoms, the median ab- solute error was 0.048 (IQR: 0.077-0.037) for AR and 0.138mm (IQR: 0.227-0.107mm) for DiN. Median relative error was 1.9% for AR and < 6.4% for DiN at the highest tested noise level (CNR = 2.66). Error in VDM output increased with slice thickness, with highest median relative error of 1.4% for AR and 6.3% for DiN at slice thickness of 2.0 mm. Respiratory motion of the aorta resulted in maximal absolute error of 3% AR and 0.6 mm in DiN, but bulk translations in aortic position had a very small effect on measured AR and DiN values (relative errors < 1%). VDM-derived measurements of magnitude and location of maximal diameter change demonstrated significantly high accuracy and lower variability compared to two expert manual raters (p < 0.03 across all comparisons). Conclusions: VDM yields accurate, three-dimensional assessment of aortic growth in TAA patients and is robust to factors such as image noise, respiration-induced translations and differences in patient position. Further, VDM significantly outperformed two expert manual raters in assessing the magnitude and location of aortic growth despite optimized experimental measurement conditions. These results support validation of the VDM technique for accurate quantification of aortic growth in patients and highlight important several advantages over current measurement techniques.NIH R44HL145953http://deepblue.lib.umich.edu/bitstream/2027.42/166324/1/MedPhys-VDM-Synthetic-validation[1].pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/166324/3/VDM Vlidation Synthetic Phantom.pdfSEL

Multicenter evaluation of parametric response mapping as an indicator of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156134/2/ajt15814_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156134/1/ajt15814.pd

Intimate partner violence and infant morbidity: evidence of an association from a population-based study in eastern Uganda in 2003

<p>Abstract</p> <p>Background</p> <p>Although recent studies suggest that there is an association between intimate partner violence and child mortality, the underlying mechanisms are still unknown. It is against this background that as a secondary objective, we set out to explore whether an association exists between intimate partner violence and illness in infants.</p> <p>Methods</p> <p>We conducted a population based household survey in Mbale, eastern Uganda in 2003. Participants were 457 women (with 457 infants) who consented to participate in the study. We measured socio-demographics of women and occurrence of intimate partner violence. We measured socio-demographics, immunization, nutritional status, and illness in the previous two weeks of the children.</p> <p>Results</p> <p>The mean age of the women was 25 years (SD 5.7) while the mean age of the infants was 6 months (SD 3.5). The prevalence of lifetime intimate partner violence was 54% (95% CI 48%–60%). During the previous two weeks, 50% (95% CI 50%–54%) of the children had illness (fever, diarrhoea, cough and fast breathing). Lifetime intimate partner violence was associated with infant illness (OR 1.8, 95% CI 1.2–2.8) and diarrhoea (OR 2.0, 95% CI 1.2–3.4).</p> <p>Conclusion</p> <p>Our findings suggest that infant illnesses (fever, diarrhoea, cough and fast breathing) are associated with intimate partner violence, and provide insights into previous reports that have shown an association between intimate partner violence and child mortality, suggesting possible underlying mechanisms. Our findings also highlight the importance of intimate partner violence on the health of children, and the need for further research in this area.</p

Barriers to women journalists in Rwanda

THE PATTERNS OF gendered experiences that have led to barriers of entryand progression for respondents of the study in Rwanda, when compared to an earlier study1 conducted by Fojo and AWiM across 17 African countries, further demonstrates how many of these experiences are shared irrespective of the country. In the case of Rwanda, a country that scores highly in the shares of seats in parliament and labour force participation within the global gender equality indices, the results are perhaps more surprising for that reason. The situation in Rwanda when compared with data from the sub-Saharan Africa shows a similarity in barriers faced by women journalists, namely poor salaries, sexual harassment, and gendered roles at the workplace. Therefore, these findings, in some respects, highlight that the existence of written and well-defined gender policies does not result in their successful implementation because Rwanda is still a long way from gender equality. The results of this study, on the one hand, speak for themselves; training and education on gender equality would go a long way in successfully addressing many of the experiences shared by participants of the study. On the other hand, socio-cultural tensions surrounding the role of women in society further com- plicates how male colleagues perceive women rights and its importance. These tensions also highlight women’s rights and the ways in which society treat women journalists. Finally, this study outlines the extent to which women journalists in Rwanda themselves recognise gender discrimination and harassment when they experience them, because the data shows that whilst most women can identify when sexual harassment happens to them, there are few women who are unable to identify certain forms of sexual harassment. This study, therefore, offers a clear starting point for organisations tasked with motivating and implementing change. It helps to identify the pain points from the perspective of the women journalists they seek to support. The recommendations presented by the study stems from their lived experiences, and it is through the conscious and reflective interrogation of this, that we can truly set the path towards change

Fully Automated Pipeline for Measurement of the Thoracic Aorta Using Joint Segmentation and Localization Neural Network

Purpose: Diagnosis and surveillance of thoracic aortic aneurysm (TAA) involves measuring the aortic diameter at various locations along the length of the aorta, often using computed tomography angiography (CTA). Currently, measurements are performed by human raters using specialized software for 3D analysis, a time-consuming process, requiring 15-45 minutes of focused effort. Thus we aimed to develop a convolutional neural network (CNN)-based algorithm for fully automated and accurate aortic measurements. Approach: Using 212 CTA scans, we trained a CNN to perform segmentation and localization of key landmarks jointly. Segmentation mask and landmarks are subsequently used to obtain the centerline and cross-sectional diameters of the aorta. Subsequently, a cubic spline is fit to the aortic boundary at the sinuses of Valsalva to avoid errors related inclusions of coronary artery origins. Performance was evaluated on test set of 57 scans, with automated measurements compared against expert manual raters. Result: Joint training of segmentation and landmark localization tasks yielded higher accuracy for both tasks compared to networks trained for each task individually. Mean absolute error between human and automated was ≤ 1 mm at 6 of 9 standard clinical measurement locations. However, higher errors were noted in the aortic root and arch regions, ranging between 1.7 and 2.1 mm, although agreement of manual raters was also lower in these regions. Conclusion: Fully-automated aortic diameter measurements in TAA are feasible using a CNN-based algorithm. Automated measurements demonstrated low errors that are comparable in magnitude to those with manual raters, however, measurement error were highest in the aortic root and arch.http://deepblue.lib.umich.edu/bitstream/2027.42/177150/1/JMI.TAA.Automated.Seg.LLoc.pdfDescription of JMI.TAA.Automated.Seg.LLoc.pdf : Main Article. V1.7.2.23SEL