The cancellation rate for MRI-guided breast biopsies due to nonvisualization of suspicious lesions detected with 3T MRI is 13 percent, which is similar to rates reported for lesions detected with 1.0 and 1.5T MRI, according to a study published in the May issue of Academic Radiology.

The results also support the canceling of MRI-guided biopsies because of nonvisualization as a reasonable approach, as no subsequent cancers were detected in patients on follow-up imaging, according to authors Karen S. Johnson, MD, of Duke University Medical Center in Durham, N.C., and colleagues.

“Not seeing a previously described suspicious breast lesion on the day of MRI-guided breast biopsy can be confusing and raises issues regarding appropriate patient management in this setting,” they wrote. “It is therefore important for radiologists to be aware of the frequency of occurrence, which lesions are most likely to resolve, and what steps to take when the situation arises.”

Studies have shown that nonvisualization of previously identified MR-detected lesions leads to biopsy cancellation between 5-15 percent of the time, though those studies largely consisted of the use of 1.0 and 1.5T MRI, explained the authors.

To determine how 3T MRI compares, Johnson and colleagues conducted a retrospective review of 117 suspicious 3T MRI-detected lesions in 101 patients who were scheduled for MRI-guided procedures, with comparisons made between completed and canceled procedures.

Results showed MRI-guided breast biopsies were canceled in 13 percent of cases due to nonvisualization, reported the authors. Breaking down the canceled procedures by suspected lesion subtype revealed 73 percent were nonmasslike enhancements, 20 percent were masses, and 7 percent were of the focus subtype. Nonvisualization was not associated with patient age, menopausal status, lesion type, size, breast density or background parenchymal enhancement, according to Johnson and colleagues.

Since no cancers were discovered on follow-up imaging after a canceled procedure, the authors concluded that a six-month follow-up MRI is a safe and reasonable approach in the situation as long as “prudent and cautious measures are taken at the time of biopsy to ensure lesion resolution and if follow-up imaging can be consistently performed.”