Dependence of Shape-Based Descriptors and Mass Segmentation Areas on Initial Contour Placement Using the Chan-Vese Method on Digital Mammograms

Table 6

Mean values for the Jaccard similarity coefficient (JSC) and the Euclidean distances of the masses. The mean values and ranges of percentage differences in boundary moments (, , and ), percentage differences in shape convexity (%ΔSC), and percentage differences in shape rectangularity (%ΔSC) for the masses, labelled as groups with predefined margin characteristics and also a group with arbitrary margin characteristics, due to changes in the location of the initial level set contours evolved with tuneable parameters , and , .

Margin characteristics	Obscured/ill-defined margins		Distinct/well-defined margins		Unlabelled margins
Tuneable parameters	,	,	,	,	,	,
Average JSC	0.81 ± 0.01	0.87 ± 0.13	0.96 ± 0.03	0.95 ± 0.06	0.89 ± 0.02	0.92 ± 0.09
Average DF	0.09 ± 0.05	0.05 ± 0.04	0.05 ± 0.02	0.04 ± 0.02	0.07 ± 0.05	0.05 ± 0.03
Mean of	23.9%	17.5%	8.9%	11.4%	16.4%	14.5%
Range of	1.0–87.0%	0–62.6%	0.3–25.0%	0–24.4%	1.0–87.0%	0–62.6%
Mean of	24.5%	17.2%	8.6%	9.6%	16.6%	13.4%
Range of	1.7–86.8%	0–59.1%	2.1–33%	0–46.0%	1.7–86.8%	0–59.1%
Mean of	32%	20.1%	14.1%	13.4%	23.1%	16.8%
Range of	1.4–86.0%	0–80.9%	0.9–53.0%	0–54.0%	0–86.0%	0–80.9%
Mean of %ΔSC	8.3%	2.4%	4.5%	2.9%	6.4%	2.7%
Range of %ΔSC	0.0–28.1%	0–21.0%	0.07–17.2%	0.2–13.9%	0.3–28.1%	0–21.0%
Mean of %ΔSR	11.7%	7.6%	5.7%	4.3%	8.7%	5.9%
Range of %ΔSR	0.1–42.0%	0–38.9%	0.04–14.9%	0–21.9%	0.1–42.0%	0–38.9%