CT and MRI based contouring in two examples with high and low cavity visualization scores (CVS). Observers’ delineations are white and expert consensus (EC) contours black. (A) Case with a CVS of 4.8 on CT and 5 on MRI: mean generalized conformity index (CIgen), accuracy index (AI) and inter-delineation distance (IDD) were 0.79, 0.85 and 2.4 mm on CT and 0.80, 0.86 and 2.2 mm on MRI. (B) Case with a CVS of 2 on CT and 3 on MRI: mean CIgen, AI and IDD were 0.46, 0.61 and 6 mm for CT and 0.63, 0.73 and 4.5 mm for MRI.