Comparison of two apparent diffusion coefficient measurements of breast lesions / 实用放射学杂志

ABSTRACT

Objective To evaluate two methods of selecting region of interest (ROI)to measure the apparent diffusion coefficient (ADC)of breast lesions on diffusion-weighted imaging (DWI).Methods MRI findings (including plain MRI,dynamic contrast-en-hanced MRI and DWI)of 5 3 cases with breast mass confirmed by pathology were analyzed retrospectively.Two observers independ-ently measured the ADC of breast lesions by the method of fixed ROI with the size of 10 mm2 ±2 mm2 and the routine method.The mean ADCs of benign and malignant breast lesions were compared between two methods and two observers by using paired samples T-test.The values of ADC diagnosing breast cancer were compared between the two methods by using the receiver operating charac-teristic (ROC)curve.Results Among 62 lesions of 53 cases,33 lesions were malignant,and 29 lesions were benign.For the first observer,the mean ADCs of benign and malignant lesions were (1.647±0.359)×10-3 mm2/s and (1.136±0.227)×10-3 mm2/s measured by the fixed ROI method,respectively.The area under the ROC was 0.897.The mean ADCs of benign and malignant le-sions were (1.603±0.415)×10-3mm2/s and (1.251±0.237)×10-3 mm2/s measured by the routine method,respectively.The area under the ROC was 0.768.For another observer,the mean ADCs of benign and malignant lesions were (1.647±0.357)× 10-3 mm2/s and (1.130±0.250)×10-3 mm2/s measured by the fixed ROI method,respectively.The mean ADCs of benign and malignant lesions were (1.590± 0.390)×10-3 mm2/s and (1.250±0.237)×10-3 mm2/s measured by the routine method,respec-tively.There was no significant difference for the mean ADC of benign lesions between the two methods.However,there was sig-nificant difference for the mean ADC of malignant lesions between the two methods.The diagnostic value of ADC measured by the fixing method was better than that of the routine method (P=0.008).There were no significant differences for ADCs of benign and malignant lesions between the two observers.Conclusion DWI has an important value for differential diagnosis of benign and malignant breast lesions.The measurement of ADC by the fixed and smaller ROI is better than that by the routine ROI for dis-tinguishing malignant from benign breast lesions.