VALUE OF DIFFUSION-WEIGHTED IMAGE AND APPARENT DIFFUSION COEFFICIENT FACTOR IN DIFFERENTIATION OF SOLID BREAST LESIONS

Abstract

Conventional imaging modalities as mammography and ultrasound remain the method of choice for routine screening programs and is the 1st imaging aid, but conventional assessment have well-known limitations, such as inaccurate differentiation between benign and malignant lesions and estimation of the size of malignant tumors also,there is limitation in differentiation between recurrence and scar tissue in post operative cases. The sensitivity of breast MRI for the detection of cancer is the greatest of all imaging techniques and when the findings of conventional imaging are inconclusive (i.e. BI-RADS 0), MRI can be used as a problem-solving modality, it is also better at identifying the true extent of cancer when multifocal disease or ductal carcinoma in situ is present. Although contrast material–enhanced magnetic resonance (MR) imaging of the breast is exquisitely sensitive for detection of invasive breast cancer, its reported specificity is variable. Diffusion-weighted imaging (DWI), if further clinical evaluation is needed, represents an easy non time consuming complementary quantitative breast imaging sequence. Based on diffusion properties; ADC mapping provides valuableinformation on benign and malignant lesions by characterizing tumor cellularity. DWI has high specificity for breast malignant lesions and has the potential to analyze cancer extension. The ADC is a sensitive and specific parameter in differentiating benign and malignant breast lesions. The calculated ADC value is clearly affected by the scanning parameters used for DWI. That is the reason for the different cut off values found for the discrimination of the malignant from benign lesions among different studies. So, all MRI sites should determine their own cut off values according to the DWI sequence used for breast imaging. In conclusion, we can say that DWI is a short unenhanced scan that can be inserted easily into standard clinical breast MRI protocols as a potential adjunct that can be added routinely to conventional breast MRI. ADC values derived from it can have apotential role in differentiation between benign andmalignant breast lesions with high sensitivity and specificity.