Time to enhancement derived from ultrafast breast MRI as a novel parameter to discriminate benign from malignant breast lesions

- New view-sharing sequences (e.g. TWIST) enable ultrafast dynamic breast MRI.
- TWIST sequences accurately characterize the inflow of contrast in breast lesions.
- TTE evaluation allows breast lesion classification with very high accuracy.
- The use of TTE significantly increases the specificity of breast MRI.
- TWIST imaging may increase the potential of breast MRI as screening tool.

ObjectivesTo investigate time to enhancement (TTE) as novel dynamic parameter for lesion classification in breast magnetic resonance imaging (MRI).MethodsIn this retrospective study, 157 women with 195 enhancing abnormalities (99 malignant and 96 benign) were included. All patients underwent a bi-temporal MRI protocol that included ultrafast time-resolved angiography with stochastic trajectory (TWIST) acquisitions (1.0 × 0.9 × 2.5 mm, temporal resolution 4.32 s), during the inflow of contrast agent. TTE derived from TWIST series and relative enhancement versus time curve type derived from volumetric interpolated breath-hold examination (VIBE) series were assessed and combined with basic morphological information to differentiate benign from malignant lesions. Receiver operating characteristic analysis and kappa statistics were applied.ResultsTTE had a significantly better discriminative ability than curve type (p < 0.001 and p = 0.026 for reader 1 and 2, respectively). Including morphology, sensitivity of TWIST and VIBE assessment was equivalent (p = 0.549 and p = 0.344, respectively). Specificity and diagnostic accuracy were significantly higher for TWIST than for VIBE assessment (p < 0.001). Inter-reader agreement in differentiating malignant from benign lesions was almost perfect for TWIST evaluation (κ = 0.86) and substantial for conventional assessment (κ = 0.75).ConclusionsTTE derived from ultrafast TWIST acquisitions is a valuable parameter that allows robust differentiation between malignant and benign breast lesions with high accuracy.