MR imaging can detect lesions that are not seen on mammography and sonography. Because tissue diagnosis of suspicious lesions is often required, the ability to perform MR-guided biopsy or wire localization is important. However, MR-guided core needle biopsies have been restricted because of the limited availability of MR compatible core biopsy needles, says Xiaoming Chen, MD, PhD, assistant professor in the department of radiology at University of Washington School of Medicine, Seattle, and an author of the study.
“This new method uses an MR-compatible coaxial device, which consists of an outer titanium sheath and an inner titanium stylet to target the lesion, and a standard stainless steel 14-gauge core biopsy needle to sample the lesion. The titanium sheath, which is inserted into the breast tissue, is imaged with the breast so we can confirm that the tip of the sheath is right at the location of the lesion,” says Dr. Chen. After the lesion is localized, the patient is moved outside of the bore of the magnet, where the biopsy is performed. Because the sheath is in line with the lesion, the radiologist can use the stainless steel core biopsy needle to complete the procedure. “The 14-gauge stainless steel needle is very effective in terms of sampling and is less expensive,” Dr. Chen adds.
Constance Lehman, MD, PhD, Dr. Chen, and other researchers from University of Washington Medical Center and Seattle Cancer Care Alliance reviewed 35 breast biopsies from 29 women ages 35-74. Each patient underwent an MR-guided breast biopsy using this new method. All biopsies were technically successful, says Dr. Chen. Biopsies indicated cancer in eight patients, and high-risk lesions (atypical ductal hyperplasia) in five patients. Surgical follow-up confirmed malignancy in all eight patients. Two of the five patients with high-risk lesions were also upgraded to malignancy after surgery, says Dr. Chen.
“Other studies have been done on MR-guided biopsy using MR compatible core biopsy needles and a 1.5T closed MR scanner, or using steel core biopsy needles with a 0.5T open scanner, but this is the first time the 14-gauge stainless steel needle has been used with a closed 1.5T MR imaging scanner,” says Dr. Chen.
The study will be presented May 5, during the American Roentgen Ray Society Annual Meeting in San Diego.
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