Unfortunately, mammograms miss 20-25% of all cancers. They also underestimate the size of DCIS in a third of all lumpectomy patients. When this happens, the surgeon misses some DCIS and another surgery is needed. MRIs, which use magnets rather than radiation, can find what mammograms miss.
According to a new study published in Academic Radiology in 2018, performing MRI on patients with non-invasive breast cancer can provide additional value.
The authors studied data from 295 patients with ductal carcinoma in situ (DCIS), focusing on 123 patients who received both mammography and breast MRI. The mean patient age was 57 years old. The mean tumor size was 39.6 mm.
Overall, the DCIS was clinically occult in the mammography results for more than 24 percent of patients. DCIS was clinically occult in more than 1 percent of the breast MRI results.
MRI outperforms MG in the detection and size estimation of DCIS and can reduce positive margin rates.
According to a 2010 JNCI article by Dr. Constance Lehman: “Over the last decade, research has confirmed that of all imaging tools, MRI has the highest sensitivity in detection of DCIS (compared with mammography and ultrasound).” This is especially true of the more aggressive high grade DCIS. A 2007 study by University of Bonn radiologist Professor Christiane Kuhl found that MRI detected 98% of high grade DCIS while mammography found only 52%. According to her, this is because high grade DCIS does not develop the micro calcifications that mammograms detect, but instead develops blood vessels which absorb the contrast dye used in an MRI. Dr. Kuhl’s most recent study demonstrated that a shorter and possibly less expensive breast (FAST ) MRI protocol seems to be just as accurate and far less expensive.
In 1996, a small study concluded: RODEO MR imaging enabled accurate determination of tumor extent in 21 of 22 (95%) patients. Mammography depicted 18 of 19 DCIS lesions. No mammographic feature helped differentiate pure DCIS from DCIS with micro-invasion. Mammography enabled accurate determination of tumor extent in 14 of 19 (74%) patients. See Abstract here.
The Aurora RODEO MRI offered at 35 locations in the United States, is a dedicated MRI, meaning it is used only for breast imaging. Its unique technology provides sharper 3-D images and better resolution than a standard whole body MRI. According to Dr. Steven Harms, referring to the RODEO MRI in a 2006 interview for Radiology Today, “We get three times the signal-to-noise ratio (SNR) of most 3DFT images. We’re using that SNR to improve resolution and improve the contrast resolution. And there are significant gains in both of those. The image resolution by the number of voxels we generate is three times that of what we had before. We also reduce scan time, which is less than half of what it was and contrast is about twice what it was before. It’s a considerable gain.”
In fact, a 2012 study by Dr. Bruce J. Hillman etal showed that, while the false negative rate for whole body MRI has historically averaged 15%, the false negative rate for the RODEO MRI is less than 1%. In other words, if a RODEO MRI finds no cancer, there is only a 1% chance that it missed something, while with whole body MRI there is still a 15% chance cancer was missed. This study also showed that while whole body MRI has been criticized for its high false positive rates, typically between 32 and 41%, RODEO MRI has a very low false positive rate of only 11%. This means if a RODEO MRI finds something suspicious, the chances of an unnecessary biopsy are much lower.
With such good numbers, the Aurora RODEO MRI is a highly accurate and useful imaging tool, especially for DCIS. With its 1% false negative rate, it can provide peace of mind as an annual screening device for higher risk patients. Its accurate 3-D mapping can also assist surgeons in providing more tailored excisions and biopsies of DCIS that cannot be seen on a mammogram, while its low 11% false positive rate protects patients from unnecessary biopsies.
More information about Aurora 1.5T Dedicated Breast MRI System here.
*According to Dr. Michael Lagios, any “dedicated” breast MRI is as effective as an Aurora RODEO MRI. This means the MRI machine is used exclusively for breast imaging and is not used to image other body parts. Just like mammography is used at breast imaging centers strictly for breast imaging.