Breast MRI demonstrating marked enhancement (bright area) which was confirmed to be cancer.
In this method, the breast is scanned in an MRI device before and after the intravascular injection of a contrast agent (Gadolinium DTPA). The pre-contrast images are "subtracted" from the post-contrast images, and any areas that have increased blood flow are seen as bright spots on a dark background. Since breast cancers generally have an increased blood supply, the contrast agent causes these lesions to "light up" on the images.
Current indications for breast MRI include but are not limited to the screening of high-risk patients (such as those with a personal or strong family history of breast cancer), evaluation of breast implants in cases of suspected implant rupture, and pre-treatment evaluation of patients with newly diagnosed breast cancer to assess the extent of the disease).
Comparison to other technologies
The available literature suggests that the sensitivity of contrast-enhanced breast MRI in detection of cancer is considerably higher than that of either radiographic mammography or ultrasound and is generally reported to be in excess of 94% (though not all reported studies have been as encouraging).
The specificity (the confidence that a lesion is cancerous and not a false positive) is only fair ('modest'), (or 37%-97%) thus a positive finding by MRI should not be interpreted as a definitive diagnosis.
The reports of 4,271 breast MRIs from eight large scale clinical trials were reviewed in 2006. Overall the sensitivity ranged from 71% to 100% in these reports, however the call-back rates were low at 10% and the risk of having a benign biopsy was reported at 5%, a significant improvement over mammography.
Several medical instrument vendors have entered this arena with breast MRI solutions. One company, Aurora Systems, is the only manufacturer to make a breast-dedicated unit and as the exclusive patent holder of certain solutions to fat signal suppression that appear to be more or less essential. Siemens, General Electric and Philips Medical, main manufacturers of MRI instruments, offer breast MRI products or add-ons, and several third-party companies offer aftermarket products to enable breast MRI on conventional MRI instruments.
- Magnetic Resonance Imaging of the Breast
- DeMartini W, Lehman C, Partridge S (April 2008). "Breast MRI for cancer detection and characterization: a review of evidence-based clinical applications". Acad Radiol 15 (4): 408–16. doi:10.1016/j.acra.2007.11.006. PMID 18342764.
- Lehman CD (2006). ""Role of MRI in screening women at high risk for breast cancer"". Journal of Magnetic Resonance Imaging 24 (5): 964. doi:10.1002/jmri.20752. PMID 17036340.