The impact of cardiopulmonary hemodynamic factors in volumetry for pulmonary nodule management

Abstract

Background The acceptance of coronary CT angiogram (CCTA) scans in the management of stable angina has led to an exponential increase in studies performed and reported incidental findings, including pulmonary nodules (PN). Using low-dose CT scans, volumetry tools are used in growth assessment and risk stratification of PN between 5 and 8 mm in diameter. Volumetry of PN could also benefit from the increased temporal resolution of CCTA scans, potentially expediting clinical decisions when an incidental PN is first detected on a CCTA scan, and allow for better resource management and planning in a Radiology department. This study aims to investigate how cardiopulmonary hemodynamic factors impact the volumetry of PN using CCTA scans. These factors include the cardiac phase, vascular distance from the main pulmonary artery (MPA) to the nodule, difference of the MPA diameter between systole and diastole, nodule location, and cardiomegaly presence. Materials and methods Two readers reviewed all CCTA scans performed from 2016 to 2019 in a tertiary hospital and detected PN measuring between 5 and 8 mm in diameter. Each observer measured each nodule using two different software packages and in systole and diastole. A multiple linear regression model was applied, and inter-observer and inter-software agreement were assessed using intraclass correlation. Results A total of 195 nodules from 107 patients were included in this retrospective, cross-sectional and observational study. The regression model identified the vascular distance (p < 0.001), the difference of the MPA diameter between systole and diastole (p < 0.001), and the location within the lower or posterior thirds of the field of view (p < 0.001 each) as affecting the volume measurement. The cardiac phase was not significant in the model. There was a very high inter-observer agreement but no reasonable inter-software agreement between measurements. Conclusions PN volumetry using CCTA scans seems to be sensitive to cardiopulmonary hemodynamic changes independently of the cardiac phase. These might also be relevant to non-gated scans, such as during PN follow-up. The cardiopulmonary hemodynamic changes are a new limiting factor to PN volumetry. In addition, when a patient experiences an acute or deteriorating cardiopulmonary disease during PN follow-up, these hemodynamic changes could affect the PN growth estimation.

Factors influencing the outcome of volumetry tools for pulmonary nodule analysis: a systematic review and attempted meta-analysis

“…In a recent study by Guedes Pinto et al, the authors reported the location in both the axial (anterior, middle, or posterior) and coronal (upper, middle, lower) planes, additionally measuring the vascular distance along the pulmonary arteries, from the main pulmonary artery (MPA) to the nodule using multiplanar reformatting, which proved to be statistically significant [ 113 ]. Conversely, the location within a lobe [ 18 ] or segment [ 98 ] was not proven to be statistically significant.…”

“…Guedes Pinto et al investigated the impact of cardiopulmonary haemodynamic factors on volumetry tools, including the cardiac phase, calibre change of the MPA between systole and diastole, the vascular distance between the MPA and the nodule, and nodule's location along the axial (related to hydrostatic pressure) and coronal plane (related to vascular section area), all statistically significant except the cardiac phase. The authors proposed a theoretical model where the volume of a given nodule is affected by the dynamic vascular pressure as blood travels from the heart to the nodule [ 113 ]. In another study by the same authors, the variability of volumetry vastly exceeded the criterion for clinical significance when comparing measurements in opposing cardiac phases (systole vs diastole [− 47%, 52.3%]), with the lower variability seen when comparing two measurements in diastole ([− 18.9%, 19.7%]) [ 8 ].…”

“…However, there is considerable overlap in risk factors between coronary artery disease and lung cancer. Patients enrolled in LCS are also at risk of cardiovascular events, with some authors advocating a role for dual screening [ 113 ].…”

“…Counter-intuitively, allowing manual correction of the segmentation improves the tool’s performance [ 60 , 102 , 118 ]. This is explained because inadequately segmented nodules tend to be outliers (i.e., either including adjacent structures [ 113 ] or incompletely segmenting the nodule [ 20 ]), resulting in higher variability and lower observer agreement.…”