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DESCRIPTIONThe use of computer-aided evaluation (CAE) may assist radiologists’ interpretation of contrast-enhanced magnetic resonance imaging (MRI) of the breast, and improve the accuracy of diagnosis of malignancy.
The use of computer-aided evaluation (CAE) is proposed to assist radiologists’ interpretation of contrast-enhanced magnetic resonance imaging (MRI) of the breast. MRI of the breast is suggested as an alternative or adjunct to mammography or other screening and diagnostic tests because of its high sensitivity in detecting breast lesions. However, it has a high false positive rate because of the difficulty in distinguishing between benign and malignant lesions. MRI may be used to screen women at high genetic risk of breast cancer or to look for more extensive disease in women diagnosed with breast cancer who are eligible for breast-conserving surgery; it is also being studied to gauge the impact of cancer treatment. The CAE systems reviewed in this policy are intended to improve the specificity of MRI in detecting or measuring malignant tissue, while maintaining the generally high sensitivity of MRI. This could potentially reduce biopsy rates if it improves the ability to identify which MRI-detected lesions are almost certainly benign. There is anecdotal information that MRI may also be used in an effort to reduce re-operation rates among patients undergoing breast-conserving surgery by more clearly identifying the tissue that should be removed. The use of CAE may also shorten the time needed to interpret breast MRI images, which currently takes longer than reading mammograms.
CAE systems for MRI essentially provide easier ways of interpreting the patterns of contrast enhancement across a series of images, which in turn may help identify lesions and their likelihood of being malignant. Two key aspects of enhancement (also called kinetics) are examined: 1) within the first minute or so, does the lesion enhance up to a certain threshold (e.g., 50%, 100% of the initial value), and 2) what is the subsequent pattern of enhancement (continues to increase, plateaus, or declines [called washout])? In contrast to computer-aided detection (CAD) systems used with mammography, CAE for MRI is not primarily aimed at identifying lesions for consideration by a radiologist. Unlike the subtle appearance of lesions on mammography, most cancers enhance on MRI. The challenge is determining which lesions are benign and which are malignant. A large number of images are produced during MRI of the breast: images are taken at varying “depths” throughout each breast multiplied by the number of times the breast is imaged to capture different time points in the enhancement process; this can produce hundreds of images. Radiologists view the images to detect suspicious areas, and then they can pick a region of interest and look at the enhancement pattern. However, there may be variations across radiologists in the regions of interest selected and in the precise definition of the region of interest. CAE systems, in contrast, use color-coding and differences in hue to indicate the patterns of enhancement for each pixel in the breast image, thereby allowing the radiologist to analyze the enhancement patterns systematically.
CAE systems for MRI of the breast were initially called CAD (computer-aided detection) systems, the same terminology used for mammography. However, the focus with MRI of the breast is on improving specificity (distinguishing malignant from benign) rather than increasing sensitivity (i.e., detection), as in mammography. The authors of 2 recent studies refer to CADStream as a computer-aided evaluation (CAE) program, and that terminology has been adopted in this policy.
Several CAE systems for use with MRI of the breast have 510(k) marketing clearance from the U.S. Food and Drug Administration (FDA). The 3TP Software Option, manufactured by 3TP LLC (now called CAD Sciences, White Plains, NY), was cleared on June 23, 2003. iCAD acquired CAD Sciences in 2008 and is now marketing a system called SpectraLook™ with CADVue™. CADstream™, which is manufactured by Confirma, Inc. (Kirkland, WA), was cleared on July 30, 2003; Merger Healthcare (Hartland, WI) subsequently acquired Confirma. A third system called Aegis (Sentinelle Medical Inc, Toronto, Ontario, Canada) received 510(k) marketing clearance from the FDA on February 9, 2007, as substantially equivalent to CADStream Version 4.0. However, in the 510(k) documents, the manufacturer states that the primary goal of Aegis is “to identify where and how deep a biopsy or localization needle should be inserted into an imaged breast.” Additional products include DynaCAD (MRI Devices Corporation, Waukesha, WI; now apparently from Invivo Corp, Orlando, FL), which was cleared July 21, 2004; and Z3D Contrast Acuity Software (Clario Medical Imaging, Inc., Seattle, WA), which was cleared September 5, 2008 and is apparently used in conjunction with CAE for MRI systems. Some of these systems may have broader uses beyond breast MRI. There also may be some overlap in the functions performed by these devices and other image-processing systems.
According to documents filed with the FDA, the 3TP Software Option is “intended to be used as a post-processing software package designed to provide a reliable means for visualizing the presence and pattern of contrast-induced enhancement on MR datasets.” It provides a color-coded image that indicates the likelihood that each pixel shows malignant or benign tissue based on the changes in enhancement at 3 points in time, which are defined by the software program. CADstream is described as a “Computer Aided Detection (CAD) system intended for use in analyzing magnetic resonance imaging (MRI) studies. CADstream automatically registers serial patient image acquisitions to minimize the impact of patient motion, segments and labels tissue types based on enhancement characteristics (parametric image maps), and performs other user-defined post-processing functions (image subtractions, multiplanar reformats, maximum intensity projections). When interpreted by a skilled physician, this device provides information that may be useful in screening and diagnosis…Patient management should not be based solely on the results of the CADstream analysis.” It also provides automated determination of volumes of interest. In addition, CADstream can be used during MRI-guided biopsies.
POLICYThe use of computer-aided evaluation (CAE) for interpretation of magnetic resonance imaging (MRI) of the breast is considered investigational.
POLICY EXCEPTIONSFederal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
POLICY GUIDELINESInvestigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
POLICY HISTORY05/09/2012: Policy added.
04/04/2013: Policy reviewed; no changes.
03/11/2014: Policy reviewed; no changes.
SOURCE(S)Blue Cross Blue Shield Association policy # 6.01.45
This may not be a comprehensive list of procedure codes applicable to this policy.