The diagnostic value of MRI for architectural distortion categorized as BI-RADS category 3-4 by mammography

Abstract

Background: Architectural distortion is a common mammographic sign that can be benign or malignant. This study investigated the diagnostic value of magnetic resonance imaging (MRI) for architectural distortions that were category 3-4 under the breast imaging reporting and data system (BI-RADS) by mammography.

Methods: We retrospectively analyzed 219 pathologically confirmed lesions in 208 patients who had BI-RADS category 3-4 architectural distortion in mammography images. Two radiologists described and categorized the architectural distortion and assigned the BI-RADS categories to the corresponding lesions on MRI images. Using the postoperative pathological diagnosis as the gold standard, we performed receiver operating characteristic (ROC) analysis for the efficacy of mammography and MRI in differentiating patients with benign or malignant lesions.

Results: Totally 151 benign lesions and 68 malignant lesions were confirmed. According to the full-field digital mammography (FFDM), 82 lesions were in BI-RADS category 3, 104 lesions in 4A, 29 lesions in 4B, and 4 lesions in 4C. The positive predictive values of FFDM for BI-RADS categories 3, 4A, 4B, and 4C were 13.4% (11/82), 27.9% (29/104), 82.8% (24/29), and 100.0% (4/4), respectively. According to MRI, 59 lesions were in BI-RADS categories 1-2, 87 lesions in 3, 39 lesions in 4, and 34 lesions in 5, with their positive predictive values being 0.0% (0/58), 2.3% (2/87), 89.7% (35/39), and 100.0% (34/34), respectively. The area under the ROC curve (AUC) of breast benign and malignant lesions differentiated by FFDM was 0.647, and the diagnostic sensitivity, specificity, and Youden index were 86.3%, 41.7%, and 0.280, respectively. The AUC of FFDM combined with dynamic contrast-enhanced MRI (DCE-MRI) in differentiating breast benign vs. malignant lesions was 0.851, and the diagnostic sensitivity, specificity, and Youden index were 89.2%, 80.7%, and 0.699, respectively. The AUC of FFDM combined with DCE-MRI and the apparent diffusion coefficient (ADC) in differentiating benign vs. malignant lesions was 0.983, and the diagnostic sensitivity, specificity, and Youden index were 98.1%, 97.5%, and 0.956, respectively.

Conclusions: MRI can improve the diagnostic efficiency of mammography in diagnosing BI-RADS category 3-4 architectural distortions and can help in the qualitative diagnosis of architectural distortion lesions.

Keywords: Mammography; architectural distortion; magnetic resonance imaging (MRI).

Figure 1

A 34-year-old female patient with right breast invasive ductal carcinoma. (A) Craniocaudal view of the FFDM with an architectural distortion in the inner upper region of the right breast that was in BI-RADS category 3 by mammography (arrow); (B) MRI diffuse axial view with a nodular DWI high-signal-intensity opacity in the inner upper region of the right breast (arrow); (C) MRI diffuse axial view, with the lesion ADC showing a significantly low signal (arrow); (D) significant enhancement of the lesion, with the TIC curve being flat. FFDM, full-field digital mammography; BI-RADS, breast imaging reporting and data system; TIC, time-intensity curve.

Figure 2

A 46-year-old female patient with left breast adenosis. (A) Craniocaudal view of the FFDM with an architectural distortion in the slightly lower region of the left breast that was in BI-RADS category 3 (arrow); (B) on the MRI diffuse axial view, DWI showed a slightly highly striped signal (arrow); (C) on the MRI enhanced oblique sagittal view, the lesion was enhanced in a patch and belonged to BI-RADS category 3 (arrow). FFDM, full-field digital mammography; BI-RADS, breast imaging reporting and data system.

Figure 3

The AUCs of FFDM, FFDM + DCE-MRI, and FFDM + DCE-MRI + ADC in differentiating breast benign vs. malignant tumors were 0.647, 0.851, and 0.983, respectively. FFDM, full-field digital mammography; DCE-MRI, dynamic contrast-enhanced MRI; ADC, apparent diffusion coefficient.