Computer-aided Detection (CAD) of Malignancy with Magnetic Resonance Imaging (MRI) of the Breast Printer-Friendly Version   

Medical Policy: 06.01.26 
Original Effective Date: May 2008 
Reviewed:  
Revised:  

This policy applies to all products unless specific contract limitations, exclusions or exceptions apply. Please refer to the member's coverage manual for benefit availability. Managed care guidelines related to referral authorization, and precertification of inpatient hospitalization, home health, home infusion and hospice services apply.

Description: 

The use of computer-aided detection (CAD) is proposed to supplement radiologists’ interpretation of contrast-enhanced magnetic resonance imaging (MRI) of the breast. MRI of the breast is suggested as an alternative to mammography or other screening and diagnostic tests because of its high sensitivity in detecting breast lesions, even among women—for example younger women and those with denser breasts—where mammography is less accurate. However, it has a high false-positive rate because of the difficulty in distinguishing between benign and malignant lesions. MRI is also being studied to look for more extensive disease in women diagnosed with breast cancer and to gauge the impact of treatment. The CAD 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. The use of CAD may also shorten the time needed to interpret breast MRI images, which currently takes much longer than reading mammograms.

CAD systems for MRI essentially provide easier ways of interpreting the patterns of contrast enhancement and washout across a series of images, which in turn may help identify lesions and their likelihood of being malignant. In contrast to CAD systems used with mammography, CAD for MRI is not aimed primarily 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 the number of time 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 select 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. CAD systems, in contrast, use color-coding and differences in hue to indicate the patterns of enhancement for each pixel in the breast image. They thereby may allow the radiologist to analyze the enhancement patterns systematically. Some CAD programs apparently incorporate morphological characteristics as well to estimate a probability of malignancy.

At the present time, it is not clear how CAD systems are to be used with MRI. In the case of CAD with conventional mammography, the radiologist reads the original films first, makes an interpretation, and then reviews the CAD results. Because CAD is not 100% sensitive, lesions detected both before the use of CAD and after viewing the CAD results may be worked up. In this way, CAD can add to the sensitivity of mammography, but not its specificity. With MRI of the breast, the sensitivity is already high and the focus is primarily on increasing the specificity. In some articles, it appears that CAD is intended as an adjunct to the initial MRI reading, just as with CAD and mammography. In other articles, it is proposed as a way of speeding up the MRI reading process, and the precise protocol to be followed in reading the MRI images is not clear.

A Technology Evaluation Center (TEC) Assessment published in 2006 summarized published articles and abstracts comparing the sensitivity and specificity of MRI of the breast interpreted with and without the use of CAD systems and reported on cancer detection based on histological results. Unfortunately, the literature on the use of CAD with MRI of the breast is sparse overall and few studies address the specific situations in which CAD with MRI may be used in the clinical setting. Many of the few articles and abstract reviewed by TEC calculated test characteristics on the basis of lesions and not the number of women or breasts. In the screening population, many women would not have any lesions. Including these women might alter the results. Given MRI’s lower sensitivity in detecting ductal carcinoma in situ (DCIS), the mix of DCIS versus masses would affect the calculations of sensitivity and specificity and might affect the impact of the CAD system.

Prospective, well-designed and executed studies that look specifically at the addition of CAD with MRI for the specific uses of interest are needed to determine whether or not the use of CAD provides a positive clinical benefit to these patients.

Policy: 

The use of computer-aided detection (CAD) for interpretation of contrast-enhanced magnetic resonance imaging (MRI) of the breast is considered investigational.

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Procedure Codes and Billing Guidelines: 

• To report provider services, use appropriate CPT* codes, Alpha Numeric (HCPCS level 2) codes, Revenue codes, and/or ICD-9-CM diagnostic codes.
• CPT code 0159T Computer-aided detection, including computer algorithm analysis of MRI imaging data for lesion characterization, pharmacokinetic analysis, with further physician review for interpretation, breast MRI. (List separately in addition to code for primary procedure).

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Selected References: 

• Blue Cross Blue Shield Association. Computer-aided detection of malignancy with magnetic resonance imaging of the breast. Blue Cross Blue Shield Association; 2006 Jun 1; vol. 21, no. 4.
• TARGET [database online]. Plymouth Meeting (PA): ECRI Institute; Computer-assisted detection (CAD) with magnetic resonance imaging (MRI) to detect breast cancer.  TARGET report 944. Oct 2003.
• DeMartini WB, Lehman CD, Peacock S et al. Computer-aided detection applied to breast MRI: assessment of CAD-generated enhancement and tumor size in breast cancers before and after neoadjuvant chemotherapy. Acad Radiol 2005;12(7):806-14.
• Williams TC, DeMartini WB, Partridge SC, Peacock S et al. Breast MR Imaging: computer-aided evaluation program for discriminating benign from malignant lesions. Radiology 2007 Jul;244(1):94-103.

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New information or technology that would be relevant for Wellmark to consider when this policy is next reviewed may be submitted to:

Wellmark Blue Cross and Blue Shield
Medical Policy Analyst
Station 304
636 Grand Ave 
Des Moines, Iowa 50309

*Current Procedural Terminology © 2008 American Medical Association. All Rights Reserved.

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