Ten Key Considerations with Breast MRI

Emphasizing that magnetic resonance imaging (MRI) is the most sensitive imaging test for the detection of breast cancer, Linda Moy, MD, FSBI, FACR, FISMRM, discussed a variety of tips for maximizing lesion conspicuity, minimizing false positives, and improving consistency in interpreting exam findings during her recent lecture at the Society of Breast Imaging (SBI)/American College of Radiology (ACR) conference.

Here are a few pertinent points from Dr. Moy’s lecture:

1. In order to facilitate optimal breast imaging with MRI, ensure the system:

• allows good fat saturation over both breasts;

• has a bilateral breast coil with prone positioning;

• has sufficient magnetic field gradients to facilitate fast gradient-echo imaging; and

• has sufficient magnetic field strength with good magnetic field homogeneity.1

2. While one study found that 1.5 T and 3 T MRI scanners are both suitable for breast MRI, Dr. Moy said 3T scanners are preferred for ultrafast MRI imaging as minimum spatial resolution is difficult to achieve with other scanners.2

3. In regard to coils, Dr. Moy emphasizes that radiologists should ensure the current hardware and software of the MRI system can accommodate the number of channels in the breast coil.

4. When it comes to axial versus sagittal imaging, sagittal imaging offers a small field of view with high spatial resolution and field uniformity, according to Dr. Moy, a professor of radiology at the New York University Grossman School of Medicine. She adds that you can get twice the number of slices in less than two minutes of acquisition time.

5. Dr. Moy said axial imaging is preferred with multiplanar reformation in the sagittal plane. She noted this approach makes it easier for radiologists to appreciate bilateral focal background parenchymal enhancement (BPE).

6. When it comes to slice thickness, Dr. Moy noted that thin slices are beneficial in evaluating foci and minimizing partial volume effects on diffuse non-mass enhancement (NME) (e.g. ductal carcinoma in situ (DCIS)).

7. In regard to breast MRI enhancement patterns, the ideal time to maximize cancer detection and normal BPE is at 90 seconds.

8. Obtain the first scan 60 to 90 seconds after contrast injection to maximize conspicuity of the cancer.

9. For high-quality breast MRI, Dr. Moy recommends multiphase T1-weighted contrast-enhanced scanning. Key aspects would include high in-plane spatial resolution (1 mm pixel sizes), thin slices (< 2.5 mm thickness) and adequate temporal resolution (one to two minutes).

10. For patients with higher BPE, there are no significant decreases in sensitivity and cancer detection rates.

References

1. Hendrik RE. High-quality breast MRI. Radiol Clin North Am. 2014;52(3):547-62.

2. Dietzel M, Wenkel E, Hammon M, et al. Does higher field strength translate into better diagnostic accuracy? A prospective comparison of breast MRI at 3 and 1.5 Tesla. Eur J Radiol. 2019;114(5):51-56.