MRI in the differential diagnosis of primary architectural distortion detected by mammography

Abstract

Purpose: We aimed to evaluate the diagnostic accuracy of a combination of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and apparent diffusion coefficient (ADC) values in lesions that manifest with architectural distortion (AD) on mammography.

Methods: All full-field digital mammography (FFDM) images obtained between August 2010 and January 2013 were reviewed retrospectively, and 57 lesions showing AD were included in the study. Two independent radiologists reviewed all mammograms and MRI data and recorded lesion characteristics according to the BI-RADS lexicon. The gold standard was histopathologic results from biopsies or surgical excisions and results of the two-year follow-up. Receiver operating characteristic curve analysis was carried out to define the most effective threshold ADC value to differentiate malignant from benign breast lesions. We investigated the sensitivity and specificity of FFDM, DCE-MRI, FFDM+DCE-MRI, and DCE-MRI+ADC.

Results: Of the 57 lesions analyzed, 28 were malignant and 29 were benign. The most effective threshold for the normalized ADC (nADC) was 0.61 with 93.1% sensitivity and 75.0% specificity. The sensitivity and specificity of DCE-MRI combined with nADC was 92.9% and 79.3%, respectively. DCE-MRI combined with nADC showed the highest specificity and equal sensitivity compared with other modalities, independent of the presentation of calcification.

Conclusion: DCE-MRI combined with nADC values was more reliable than mammography in differentiating the nature of disease manifesting as primary AD on mammography.

Figure 1

The comparison of ROC curves between absolute (ADC_int) and normalized (nADC) apparent diffusion coefficients. Area under the curve of nADC is significantly higher than that of ADC_int (P = 0.011).

Figure 2

a–i. A 52-year-old female patient presented typical architectural distortion. Mammography craniocaudal (a) and mediolateral oblique views (b) of the right breast show architectural distortion (arrows) in inner upper quadrant. Axial T2-weighted turbo inversion recovery image (c) shows an irregular nodule (arrow) with low signal. Diffusion-weighted image (d) shows slightly high signal (arrow). Apparent diffusion coefficient map (e) shows low signal (arrow); the ADC_int and nADC values are 1.02×10⁻³ mm²/s and 0.59, respectively. Axial dynamic contrast-enhanced and subtracted T1-weighted image (f) shows irregular nodule with early significant enhancement (arrow). Sagittal postcontrast axial T1-weighted image (g) shows an irregular spiculated nodule (arrow). Enhancement kinetic curve (h) shows a washout pattern. Pathologic results (i) show ductal carcinoma in situ.