Chronic obstructive pulmonary disease (COPD), is a major contributor to hospitalization and healthcare costs in North America. While the hallmark of COPD is airflow limitation, it is also associated with abnormalities of the cardiovascular system. Enlargement of the pulmonary artery (PA) is a morphological marker of pulmonary hypertension, and was previously shown to predict acute exacerbations using a one-dimensional diameter measurement of the main PA. We hypothesized that a three-dimensional (3D) quantification of PA size would be more sensitive than 1D methods and encompass morphological changes along the entire central pulmonary artery. Hence, we developed a 3D measurement of the main (MPA), left (LPA) and right (RPA) pulmonary arteries as well as total PA volume (TPAV) from thoracic CT images. This approach incorporates segmentation of pulmonary vessels in cross-section for the MPA, LPA and RPA to provide an estimate of their volumes. Three observers performed five repeated measurements for 15 ex-smokers with ≥10 pack-years, and randomly identified from a larger dataset of 199 patients. There was a strong agreement (r2=0.76) for PA volume and PA diameter measurements, which was used as a gold standard. Observer measurements were strongly correlated and coefficients of variation for observer 1 (MPA:2%, LPA:3%, RPA:2%, TPA:2%) were not significantly different from observer 2 and 3 results. In conclusion, we generated manual 3D pulmonary artery volume measurements from thoracic CT images that can be performed with high reproducibility. Future work will involve automation for implementation in clinical workflows.
Carotid artery total plaque volume (TPV) is a three-dimensional (3D) ultrasound (US) imaging measurement of carotid
atherosclerosis, providing a direct non-invasive and regional estimation of atherosclerotic plaque volume - the direct
determinant of carotid stenosis and ischemic stroke. While 3DUS measurements of TPV provide the potential to
monitor plaque in individual patients and in populations enrolled in clinical trials, until now, such measurements have
been performed manually which is laborious, time-consuming and prone to intra-observer and inter-observer variability.
To address this critical translational limitation, here we describe the development and application of a semi-automated
3DUS plaque volume measurement. This semi-automated TPV measurement incorporates three user-selected
boundaries in two views of the 3DUS volume to generate a geometric approximation of TPV for each plaque measured.
We compared semi-automated repeated measurements to manual segmentation of 22 individual plaques ranging in
volume from 2mm3 to 151mm3. Mean plaque volume was 43±40mm3 for semi-automated and 48±46mm3 for manual
measurements and these were not significantly different (p=0.60). Mean coefficient of variation (CV) was 12.0±5.1%
for the semi-automated measurements.