Question: Which computer-aided detection (CAD) code should I use to report CAD with a breast ultrasound (US)? Minnesota Subscriber Answer: According to the American College of Radiology (ACR), you should report CAD with code 76641 (Ultrasound, breast, unilateral, real time with image documentation, including axilla when performed; complete) or 76642 (Ultrasound, breast, unilateral, real time with image documentation, including axilla when performed; limited) using the unlisted code 76999 (Unlisted ultrasound procedure (eg, diagnostic, interventional)). Since you’re using an unlisted code, you’ll want to submit the full claim on paper, with documentation explaining what service the unlisted code is supporting. Make sure to include the dictation report along with a written explanation supporting the use of the code.