Mapping the diffusion tensor parameters at high spatial resolution provides a potential novel means for dissecting breast architecture. Parametric maps of λ1 and λ1-λ3 facilitate the detection and diagnosis of breast cancer.

Application of the three-time-point method permitted, in most cases, differentiation of malignant and benign lesions, even in the presence of complex breast enhancement patterns. Sensitivity for solid tumors was higher than for ductal carcinoma in situ.

The spatial resolution of three-dimensional (3D) gradientecho T1-weighted images, from 40 women with 25 malignant and 23 benign lesions, was purposely degraded to determine the role of spatial resolution in recording, analysis, and diagnosis of dynamic contrast-enhanced breast MRI. Images were recorded and analyzed at pixel resolution according to the 3TP method (Degani et al., Nat Med 1997;3:780 -782). Reduction in spatial resolution degraded the appearance of foci with fast wash-in and fast washout dynamics. This resulted in an increase in falsenegative diagnoses. The sensitivity for differentiating between malignant and benign lesions, using threshold criteria defined by the 3TP analysis, of 76% decreased to 60% and 24% for a 2-and 4-fold reduction in spatial resolution, respectively, without affecting significantly the high specificity ( Index terms: breast diagnosis; MRI; dynamic; contrast agent; spatial resolution BREAST LESIONS can be distinctly characterized by gadolinium (Gd)-based contrast-enhanced MRI (1-3). The sensitivity of breast MRI for cancer detection was found to be high (4 -13, and references cited therein); however, conflicting results were reported for the accuracy of diagnosis in terms of differentiating benign and malignant lesions (4 -13, and references cited therein). Both architectural features of the enhanced regions and dynamics of contrast enhancement served to improve the sensitivity and specificity of breast MRI diagnosis (13,14). Various methods, both empiric and model-based, have been used to extract diagnostic information from dynamic contrastenhanced signal intensity time curves (15-26). Clearly, the architectural features of lesions are better resolved in images recorded and displayed at high spatial resolution, while in dynamic contrast-enhanced images, high temporal and spatial resolution may be critical for extracting the relevant information. High temporal resolution provides detailed curves of enhancement vs. time that can be mathematically analyzed, empirically or with a modelbased equation. The spatial resolution of kinetic behavior is also significant, as tumors and particularly cancers are highly heterogeneous. Unfortunately, current standard MRI technology cannot record images with both high spatial resolution and high temporal resolution at a sufficient signal-to-noise ratio. To overcome this dilemma, we recently proposed a method that records high-resolution contrast-enhanced images at three specific time points (hence the term 3TP) (20), chosen using a model-based algorithm (27) so as to maximize the dynamic information that is guiding the diagnosis. The 3TP method was initially studied and verified in animal models of breast cancer (20, 28). The method relates changes in enhancement to the physiologic parameters that characterize malignant tumors, and differentiates them from benign ones, namely, the product of microvascular surface area and permeability of the contrast agent per unit volume (PS/V) and extracellular volume fraction (EVF) accessible to the contra...

Water diffusion anisotropy in the healthy breast can be similarly mapped by the normalized indices and by λ -λ . However, the normalized anisotropy indices fail to differentiate cancer from normal breast tissue, whereas λ -λ can assist in differentiating cancer from normal breast tissue. J. Magn. Reson. Imaging 2016;44:1624-1632.

DTI parameters are not sensitive to menstrual cycle changes, while menopause, long-term HRT, and presence of milk in lactating women affected the DTI parameters. Therefore, the timing for performing breast DTI is not restricted throughout the menstrual cycle, whereas the modulations in diffusion parameters due to HRT and lactation should be taken into account in DTI evaluation.