Initial clinical experience with contrast-enhanced digital breast tomosynthesis

Abstract

Rationale and objectives: Contrast-enhanced digital mammography and digital breast tomosynthesis are two imaging techniques that attempt to increase malignant breast lesion conspicuity. The combination of these into a single technique, contrast-enhanced digital breast tomosynthesis (CE-DBT), could potentially integrate the strengths of both. The objectives of this study were to assess the clinical feasibility of CE-DBT as an adjunct to digital mammography, and to correlate lesion enhancement characteristics and morphology obtained with CE-DBT to digital mammography, ultrasound, and magnetic resonance (MR).

Materials and methods: CE-DBT (GE Senographe 2000D; Milwaukee, WI) was performed as a pilot study in an ongoing National Cancer Institute-funded grant (P01-CA85484) studying multimodality breast imaging. Thirteen patients with ACR BI-RADS category 4 or 5 breast lesions underwent imaging with digital mammography, ultrasound, MR, and CE-DBT. CE-DBT was performed at 49 kVp with a rhodium target and a 0.27-mm copper (Alfa Aesar, Ward Hill, MA) filter. Preinjection and postinjection DBT image sets were acquired in the medial lateral oblique projection with slight compression. Each image set consists of nine images acquired over a 50-degree arc and was obtained with a mean glandular x-ray dose comparable to two conventional mammographic views. Between the precontrast and postcontrast DBT image sets, a single bolus of iodinated contrast agent (1 ml/kg at 2 ml/s, Omnipaque-300; Amersham Health Inc., Princeton, NJ) was administered. Images were reconstructed using filtered-backprojection in 1-mm increments and transmitted to a clinical PACS workstation.

Results: Initial experience suggests that CE-DBT provides morphologic and vascular characteristics of breast lesions qualitatively concordant with that of digital mammography and MR.

Conclusion: As an adjunct to digital mammography, CE-DBT may be a potential alternative tool for breast lesion morphologic and vascular characterization.

Figures

Figure 1

Digital Mammogram (A-left, B-right) In the left breast, there is a 9 mm cluster of calcifications inferoposterior to a clip from prior core biopsy (arrow). Just anterior to this cluster there is a focal asymmetry related to the recent biopsy. Right breast provided for comparison.

Figure 2

MR – Pre-gadolinium T1-weighted fat suppressed (2A, 2B) and post-gadolinium subtracted (2C, 2D) MR images of the left breast.

1. 2A: In the location of the cluster of calcifications identified on digital mammogram, there is a 1.1 cm mass that is isointense to glandular tissue (arrow).

2. 2B: 5 mm laterally, there is an approximately 1 cm ovoid region of high signal focus representing a post-biopsy hematoma (arrowhead). The focal region of low signal intensity posterior to this hematoma represents the artifact from a titanium clip.

3. 2C: Subtracted image through the mass seen in figure 2A demonstrates avid enhancement (arrow). There is a suspicious area of nodular rim-enhancement. Pathology demonstrated infiltrating ductal carcinoma.

4. 2D. Subtracted image through the area of the post-biopsy hematoma demonstrates no enhancement (arrowhead).

Figure 3

CE-DBT

1. 3A: Inferoanterior to the biopsy clip, pre-contrast DBT demonstrates a density that is more conspicuous than on the digital mammogram (arrowhead). The cluster of calcifications identified on the digital mammogram is not well demonstrated here due to motion (arrow).

2. 3B: Reconstructed post-contrast DBT images display an enhancing mass posterior to and separate from the density seen on pre-contrast images (arrow). This enhancing mass corresponds in location to the cluster of calcifications on mammography. The appearance corresponds to findings on breast MR (Figure 2), which demonstrates an enhancing suspicious mass adjacent to and separate from a non-enhancing post-biopsy hematoma (arrowhead).

Figure 4

Digital Mammogram (A-left, B-right) In the right breast, there is a 1.4 cm ill-defined focal asymmetry overlying the pectoralis muscle (arrow). Left breast provided for comparison.

Figure 5

MR

1. 5A: Pre-contrast T1-weighted fat suppressed image demonstrates a spiculated mass in the superior right breast (arrow), corresponding to the asymmetry seen on digital mammogram.

2. 5B: Post-contrast subtracted image of the mass demonstrates avid enhancement consistent with malignancy (arrow). Pathology demonstrated a 1.2 cm infiltrating ductal carcinoma.

Figure 6

CE-DBT

1. 6A: Pre-contrast DBT demonstrates a spiculated mass in the upper right breast projecting over the pectoralis muscle and corresponding to the location of the focal asymmetry on the digital mammogram (arrow). The spiculated margins of the mass are more apparent on the reconstructed tomosynthesis images than on the digital mammogram.

2. 6B: This spiculated mass displays avid non-ionic contrast enhancement on CE-DBT.

3. 6C: Subtracted reconstructed CE-DBT image highlights this enhancing, spiculated mass (zoomed image included). Highly suspicious rim-enhancement is also seen on this subtraction image.