Scientists working on the MARIUS (magnetic resonance imaging using ultrasound--systems and processor multimodal MR imaging) Project, an undertaking of the Fraunhofer Institute for Biomedical Engineering IBMT in St. Ingbert and the Fraunhofer Institute for Medical Image Computing MEVIS in Bremen, are developing a more cost-effective breast cancer biopsy technique that is supposed to be easier on patients.
MRI sometimes is used in breast cancer biopsies to ensure correct needle insertion. The problem, according to the researchers, is that the process consists of two steps: the actual imaging inside the MRI scanner, and the insertion of the biopsy needle, which requires the patient to be removed from the scanner in order to place the needle accurately. In many cases, the process must be repeated several times in order to get a sample, which can exhaust patients and increase the cost of the procedure.
The new technique requires just one scan of a patient's chest--at the beginning of the procedure. The system renders the MRI scan on screen so that they have both a live ultrasound scan and corresponding MR image available to them to guide the biopsy and display exactly where the tumor is located.
One big challenge is that a patient has to lie in different positions while undergoing an MRI and during a biopsy procedure, altering the shape of the patient's breast and shifting the location of the tumor. For this procedure, the researchers attach ultrasound probes to the patients while they are in the MRI chamber during a scan to provide a succession of ultrasound images. In this way they are able to produce two comparable sets of data from two separate imaging techniques.
While the patient undergoes biopsy, the probes remain attached and record volume data and track changes to the breast. Meanwhile, special algorithms are used to analyze the changes and update the MRI scan, which changes analogously to the ultrasound scan. Consequently during biopsy, the physician can see the updated MRI scan along with the ultrasound image on screen, allowing him to place the needle more accurately.
The technique will be on display at MEDICA 2013 in Düsseldorf, Germany later this month.
"These scanners generate strong magnetic fields, and the ultrasound device must work reliably without affecting the MRI scan," IBMT project manager Steffen Tretbar said in an announcement. The team also is developing ultrasound probes that can be attached to the body in order to provide 3-D ultrasound imaging.
Use of an MRI technique called diffusion-weighted imaging (DWI) could decrease false positive breast cancer findings and prevent unnecessary biopsies, according to a study published last year in the journal Radiology.
To learn more:
- read the announcement