[Diagnostic value of ADC and rADC of diffusion weighted imaging in malignant breast lesions]

The aim of this study was to evaluate the value of diffusion weighted imaging (DWI) in the diagnosis of patients with breast diseases.

Fifty-three consecutive patients were scanned with GE signa HDx 1.5 T magnetic resonance system equipped with 8-channel breast coil. DWI was scanned by SE-EPI sequence in b values of 500 s/mm(2) and 800 s/mm(2), respectively. The apparent diffusion coefficients (ADC) of these lesions were measured. The mean apparent diffusion coefficients (ADC) of these lesions were calculated in b values of 500 s/mm(2) and 800 s/mm(2), respectively. These lesions' ADC value (rADC) was counted respectively and the result of the rADC was equal to the lesion's ADC divided by the ADC of the ipsilateral normal breast tissue. Threshold of ADC and rADC for differential diagnosis was acquired by ROC (receiver operating characteristic curve) analysis. Different imaging technologies were evaluated emphasizing their sensitivity, specificity and accuracy.

Sixty-six lesions of 53 cases were confirmed by pathology, including 39 malignant lesions and 27 benign lesions. (1) b = 500 s/mm(2), the threshold of ADC value was 1.435 x 10(-3) mm(2)/s, with a sensitivity of 82.1% and a specificity of 81.5%. The threshold of rADC value was 0.62, with a sensitivity of 76.9% and a specificity of 100%. (2) b = 800 s/mm(2), the threshold of ADC value was 1.295 x 10(-3) mm(2)/s, with a sensitivity of 79.5% and a specificity of 81.5%. The threshold of rADC value was 0.71, with a sensitivity of 89.7% and specificity of 88.9%. (3) The area under the ROC curve was increased for the four diagnostic indicators (ADC(500), ADC(800), rADC(500), rADC(800)).

DWI spends short time, and it doesn't need contrast material. ADC value and rADC value have a high sensitivity and specificity as a diagnostic indicator. DWI is helpful in improving the specificity of MR and may become one of valuable conventional procedures for breast tumor diagnosis.