Analysis of OCR, ECAR and OCR/ECAR ratio between different sizes of CRCs and adjacent normal mucosae. (a) OCR of normal mucosae and CRCs (<4 cm, 4 to 6 cm and ≥ 6 cm. N = 34, 41 and 18. P = .040, 0.005 and 0.013, respectively). (b) ECAR of normal mucosae and CRCs (<4 cm, 4 to 6 cm and ≥ 6 cm. N = 34, 41 and 18. P = .113, 0.159 and 0.480, respectively). (c) OCR/ECAR of normal mucosae and CRCs (<4 cm, 4 to 6 cm and ≥ 6 cm. N = 34, 41 and 18. P = .0002, 0.003 and 0.011, respectively). Groups were compared by paired t-test. The box and whisker plot shows a 5-number data summary: minimum, 1st quartile, median, 3rd quartile and maximum. The box is divided at the median. The length of the box is the interquartile range. The 1st quartile is the bottom line. The 3rd quartile is the top line.