Correlation of apparent diffusion coefficient value with prognostic parameters of endometrioid carcinoma

<jats:sec><jats:title>Purpose</jats:title><jats:p>To correlate the apparent diffusion coefficient (ADC) of endometrioid carcinoma with histological tumor grade and degree of myometrial invasion.</jats:p></jats:sec><jats:sec><jats:title>Materials and Methods</jats:title><jats:p>3T diffusion‐weighted (DW) magnetic resonance (MR) images of 63 patients were retrospectively reviewed. Two readers measured tumor ADC according to a freehand region of interest (ROI) and a round ROI. Mean and minimum ADCs were correlated with prognostic parameters.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The minimum ADC was 0.64 × 10<jats:sup>−3</jats:sup>mm<jats:sup>2</jats:sup>/s for grade 1 (G1, <jats:italic>n</jats:italic> = 42), 0.62 for grade 2 (G2, <jats:italic>n</jats:italic> = 14), 0.46 for grade 3 (G3, <jats:italic>n</jats:italic> = 7) on freehand ROI. There were significant differences between G1 and G3 (<jats:italic>P</jats:italic> = 0.007), and G2 and G3 (<jats:italic>P</jats:italic> = 0.038). No significant correlation was found between tumor grade and mean ADC (0.85 for G1, 0.82 for G2, and 0.72 for G3, <jats:italic>P</jats:italic> = 0.166). The minimum ADC was significantly lower for patients with deep (<jats:italic>n</jats:italic> = 21, 0.54) than for those with superficial (<jats:italic>n</jats:italic> = 39, 0.65) myometrial invasion. Conversely, mean ADC did not differ significantly (0.84 for superficial and 0.78 for deep myometrial invasion, <jats:italic>P</jats:italic> = 0.081). The same tendency was shown on round ROI.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The minimum ADC correlates with prognostic parameters of endometrial carcinoma more strongly than mean ADC. Lower minimum ADC is associated with higher histological tumor grade and higher degree of myometrial invasion. <jats:bold>J. Magn. Reson. Imaging 2015;41:213–219.</jats:bold> © <jats:bold>2013 Wiley Periodicals, Inc</jats:bold>.</jats:p></jats:sec>