Comparing algorithms for automated vessel segmentation in computed tomography scans of the lung: the VESSEL12 study.

The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of different algorithms to identify vessels in thoracic computed tomography (CT) scans. Vessel segmentation is fundamental in computer aided processing of data generated by 3D imaging modalities. As manual vessel segmentation is prohibitively time consuming, any real world application requires some form of automation. Several approaches exist for automated vessel segmentation, but judging their relative merits is difficult due to a lack of standardized evaluation. We present an annotated reference dataset containing 20 CT scans and propose nine categories to perform a comprehensive evaluation of vessel segmentation algorithms from both academia and industry. Twenty algorithms participated in the VESSEL12 challenge, held at International Symposium on Biomedical Imaging (ISBI) 2012. All results have been published at the VESSEL12 website http://vessel12.grand-challenge.org. The challenge remains ongoing and open to new participants. Our three contributions are: (1) an annotated reference dataset available online for evaluation of new algorithms; (2) a quantitative scoring system for objective comparison of algorithms; and (3) performance analysis of the strengths and weaknesses of the various vessel segmentation methods in the presence of various lung diseases.

Motion analysis of right ventricular dysfunction under mild or moderate pressure overload caused by acute pulmonary embolism.

Acute pulmonary embolism (APE) is the third most common cause of death in the United States. Appearing as a sudden blockage in a major pulmonary artery, APE may cause mild, moderate or severe right ventricular (RV) overload. Although severe RV overload produces diagnostically obvious RV mechanical failure, little progress has been made in gaining a clinical and biophysical understanding of moderate and mild acute RV overload and its impact on RV functionality. In the research described here, we conducted a pilot study in pigs using echocardiography and observed the following abnormalities in RV functionality under acute mild or moderate RV overload: (i) occurrence of paradoxical septal motion with "waving" dynamics; (ii) decrease in local curvature of the septum (p < 0.01); (iii) lower positive correlation between movement of the RV free wall and movement of the septum (p < 0.05); (iv) slower rate of RV fractional area change (p < 0.05); and (v) decrease in movement stability, particularly in the middle of the septum (p < 0.05).