Table 2. Prevalence and computed tomographic findings of incidental lesions in the anterior mediastinal mediastinum.

Source	Study from the Early Lung Cancer Action Project	Study from the Framingham Heart Study	Study conducted at two health checkups centers
Size cutoff for defining incidental lesions*	≥7 mm	≥5 mm	≥5 mm
Number of incidental lesions	41	23	413
Prevalence (95% confidence interval)	0.45% (0.32–0.60%)	0.89% (0.59–1.35%)	0.73% (0.66–0.80%)
Computed tomographic findings
Median long-axis diameter (mm)	Between 10 and 30	18 [11–30]*	12 [9–16]*
Median short-axis diameter (mm)	Unknown	11 [7–14]*	8 [6–10]*
Attenuation (Hounsfield units)	Unknown	32 [10–56]*	43 [26–57]*
Round to oval shape	95%	68%	99%
Focal calcification	5%	9%	Unknown

*, Data in paracenteses indicate interquartile range.