Loading...
1 results
Search Results
Now showing 1 - 1 of 1
- The influence ofthe cardiac cycle phase on the volumetry of pulmonary nodulesPublication . Pinto, Erique Manuel Correia Guedes; Irion, KIaus Loureiro; Barata, Luís Manuel TabordaThere is a significant overlap in the risk factors and population at risk of lung cancer and coronary artery disease (CAD). Lung cancer screening (LCS) has proven to reduce cancer-related mortality, and there is an ongoing, worldwide effort to implement LCS programmes. This will undoubtedly increase requests for low-dose cr (LDCf) scans. Likewise, as new cr scanner technology becomes more ubiquitous, demand for coronary cr angiography (CCTA) is also expected to rise in this population, as cardiovascular diseases remain one of the maio causes of morbidity and mortality in the industrialised world. This trend creates an opportunity for dual-screening oflung cancer and CAD, which has been suggested before but not yet investigated. The ability to screen for lung cancer using CerA scans, could avoid unnecessary duplication of resources, improve the costeffectiveness of screening programmes and avoid side effects of radiation exposure. ln this thesis dissertation, I will explore the use of pulmonary nodule volumetry tools in CCTAscans. To approach this question, we reviewed the scientific literature on incidental findings (IF) in CerA scans and found that pulmonary IFs are the most common despite the lack of consensus regarding their reporting and management. The prevalence of pulmonary IFs, mostly small pulmonary nodules, supports the premise of dual-role screening and our research 's c1inical relevance. Volumetry plays a crucial role in managing indetenninate pulmonary nodules. Volume doubling time (VDT) is current1y considered the best predictor of malignancy for indetenninate nodules and is criticaI to their management and the early diagnosis oflung cancero However, volumetry is affected b:y numerous known influencing factors, some of which will be relevant when comparing d ifferent scanning protocols such as LDCT and CerA. Important1y, the volumetry tools dedicated to pulmonary nodules are not validated in CCTA scans. This research has systematica1ly reviewed the current body of evidence regarding the influencing factors of volumetry and consolidated the current knowledge, highlighting its high heterogeneity and poor c1inical applicability. I approached the question from two complernentcuy perspectives. ln the first original study, a multiple linear regression model was used to identify the statistica11y significant cardiopulmoncuy hemodynamic factors affecting pulmonary nodule volumetry, including the cardiac cycle phase, the vascular distance between the main pulmonary artery (MP A) and the nodule, and the anteroposterior and craniocaudallocation of the nodule as it relates to hydrostatic pressure and vascular cross-sectional area, respectively. Contrary to the results from BoIl et aI., the cardiac phase was not significant in this study, while the other factors were. ln the second original study, a relative Bland-Altman analysis between the sarne and opposing cardiac phases found that measurement variability between opposing cardiac phases was increased in a matter that could be c1inica1ly significant, potentially resulting in false-positive growth estimation. Based on the results from these two original studies, a model is presented explaining the influence of cardiopulmonary hemodynamic factors of volumetry based on the physiologica1 notion of 'transit time'. This dissertation argues that cardiopulmoncuy events like heart failure, which could occur or resolve between two follow-up examinations in LCS, can potentially lead to faJse positive screening results and must be considered. To minimise measurement variability, measurements in diastole should be consistent1y favoured when using volumetry in ECG-gated scans. Significant gaps in current knowledge are exposed and are suggested for future research.