Diagnostic performance of ADCs in different ROIs for breast lesions

The purpose of this study was to explore the diagnostic performance of apparent diffusion coefficient (ADC) values for breast lesions by different measuring methods and find out the optimum measuring method.

ADCW-mean and ADCW-min were obtained by whole-measurement method, while ADCmean and ADCmin were extracted by spot-measurement method. Four ADCs were analyzed by One-way ANOVA and Independent T-test. The diagnostic performances of these four ADCs were calculated by receiver operating characteristics (ROC) curves and the area under the curves (AUC) were compared through Z-test.

For the whole-measurement method, there were significant differences between malignant and benign lesions (ADCW-mean=1.014±0.197 for malignant, ADCW-mean=1.650±0.348 for benign, F=37.511, P<0.001; ADCW-min=0.627±0.144 for malignant, ADCW-min=1.245±0.290 for benign, F=41.446, P<0.001), as well as the spot-measurement method (ADCmean=1.010±0.234 for malignant, ADCmean=1.648±0.392 for benign, F=34.580, P<0.001; ADCmin=0.817±0.203 for malignant, ADCmin=1.411±0.357 for benign, F=40.039, P<0.001). The optimal diagnostic threshold of ADCW-mean, ADCW-min, ADCmean, and ADCmin values were 1.223×10(-3) mm(2)/s, 0.897×10(-3) mm(2)/s, 1.315×10(-3) mm(2)/s, and 1.111×10(-3) mm(2)/s, respectively. ROC curves indicated that the AUC for ADCW-min (0.969) was statistically significant higher than the AUC for ADCW-mean (0.940; Z=2.473, p=0.013), ADCmean (0.919; Z=3.691, P=0.000), and ADCmin (0.928; Z=3.634, P=0.000). The AUC for ADCW-mean was also significantly higher than the AUC for ADCmean (Z=2.863, P=0.004).

The results provided evidence that the most reliable and accurate value in demonstrating the limitation of diffusion may be ADCW-min, and it has the highest diagnostic value in distinguishing breast lesions from malignant to benign.