Single-click, semi-automatic lung nodule contouring using hierarchical conditional random fields

Lung cancer is the second most common cancer in the United States, regardless of gender. Lung cancer staging is a critical process for diagnosis and prognosis that is commonly done through the analysis of computed tomography of the chest. Analysis can be done by extracting quantitative metrics from clinician defined contours; however, defining contours manually can be a time consuming process which, in an environment where fast staging is necessary, is undesirable. Semi-automatic methods are desirable for minimizing user input while achieving similar contouring results. However, they can be hampered by image noise and complex shapes. In this paper, we present a single-click, semi-automatic contouring method for lung nodules that formulates the problem as a texture-based hierarchical conditional random field, making it robust to noise and capable of contouring complex shapes. Comparing against other semi-automatic contouring methods using clinician contours as ground truth, the proposed method achieves higher results in the sensitivity, Dice, and Jaccard metrics while achieving comparable results with the specificity and accuracy metrics.