• The choice of b values significantly affects the ADC of breast lesions. • Sensitivity and specificity are not affected by the choice of b values. • b values 0 and 1,000 s/mm (2) are recommended for optimal differentiation between benign and malignant lesions. • Contrast medium prior to DWI does not significantly affect the ADC.

The influence of microperfusion and fat suppression technique on the apparent diffusion coefficient (ADC) values obtained with diffusion weighted imaging (DWI) of normal fibroglandular breast tissue was investigated. Seven volunteers (14 breasts) were scanned using diffusion weighting factors (b values) up to 1600 s/mm(2) and the four different fat suppression techniques: STIR, fat saturation, SPAIR, and Water Excitation. The relationship between the logarithmic DW attenuation curves and b was linear for b values up to 600 s/mm(2) (R(2) > 0.999). Small differences were noted between the ADC values obtained with the various fat suppression methods, especially at the higher b values. Water Excitation had the highest mean SNR, exceeding STIR (p = 0.03) though not significantly different from fat saturation and SPAIR. In conclusion, the ADC of fibroglandular breast tissue is not influenced by microperfusion and Water Excitation is recommended because it yielded the best SNR values. These factors may be crucial in the differentiation between benign and malignant lesions.

ObjectivesTo evaluate the additional value of computer-aided detection (CAD) in breast MRI by assessing radiologists’ accuracy in discriminating benign from malignant breast lesions.MethodsA literature search was performed with inclusion of relevant studies using a commercially available CAD system with automatic colour mapping. Two independent researchers assessed the quality of the studies. The accuracy of the radiologists’ performance with and without CAD was presented as pooled sensitivity and specificity.ResultsOf 587 articles, 10 met the inclusion criteria, all of good methodological quality. Experienced radiologists reached comparable pooled sensitivity and specificity before and after using CAD (sensitivity: without CAD: 89%; 95% CI: 78–94%, with CAD: 89%; 95%CI: 81–94%) (specificity: without CAD: 86%; 95% CI: 79–91%, with CAD: 82%; 95% CI: 76–87%). For residents the pooled sensitivity increased from 72% (95% CI: 62–81%) without CAD to 89% (95% CI: 80–94%) with CAD, however, not significantly. Concerning specificity, the results were similar (without CAD: 79%; 95% CI: 69–86%, with CAD: 78%; 95% CI: 69–84%).ConclusionsCAD in breast MRI has little influence on the sensitivity and specificity of experienced radiologists and therefore their interpretation remains essential. However, residents or inexperienced radiologists seem to benefit from CAD concerning breast MRI evaluation.

Quantitative DWI has a lower NPV compared to DCE-MRI for evaluation of breast lesions and may therefore not be able to replace DCE-MRI; when implemented after DCE-MRI as problem solver for BI-RADS 3 and 4 lesions, the combined specificity improves significantly. J. Magn. Reson. Imaging 2016;44:1642-1649.