Breast MRI
Encyclopedia
One alternative to mammography
, Breast MRI or contrast enhanced magnetic resonance imaging
(MRI), has shown substantial progress in the detection of breast cancer.
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.
and is generally reported to be in excess of 95% (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, 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 recently by CD Lehman. 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.
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)
, 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.
Mammography
Mammography is the process of using low-energy-X-rays to examine the human breast and is used as a diagnostic and a screening tool....
, Breast MRI or contrast enhanced magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI), has shown substantial progress in the detection of breast cancer.
Operation
In this method, the breast is scanned in an MRI device before and after the intravascular injection of a contrast agent (GadoliniumGadolinium
Gadolinium is a chemical element with the symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined form. Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited with...
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.
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 ultrasoundUltrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
and is generally reported to be in excess of 95% (though not all reported studies have been as encouraging).
The specificity
Sensitivity and specificity
Sensitivity and specificity are statistical measures of the performance of a binary classification test, also known in statistics as classification function. Sensitivity measures the proportion of actual positives which are correctly identified as such Sensitivity and specificity are statistical...
(the confidence that a lesion is cancerous and not a false positive) is only fair, 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 recently by CD Lehman. 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.
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)
Vendors
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. SiemensSiemens
Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
, General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
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.