On 22 January 2020 the U.S. Food and Drug Administration (FDA or the agency) published three regulations formally classifying certain radiological image analyzers and related software, including computer-assisted/aided detection (CADe), as class II medical devices subject to 510(k) premarket notification with special controls. FDA also formally codified two CAD device types (radiological computer-assisted diagnostic (CADx) software and radiological computer aided triage and notification software (CADt)) addressed through De Novo Requests as class II devices and provided detailed classification regulations, including special controls, for such products going forward.
On 22 January 2020 the U.S. Food and Drug Administration (FDA or the agency) published three regulations formally classifying certain radiological image analyzers and related software, including computer-assisted/aided detection (CADe), as class II medical devices subject to 510(k) premarket notification with special controls. FDA also formally codified two CAD device types (radiological computer-assisted diagnostic (CADx) software and radiological computer aided triage and notification software (CADt)) addressed through De Novo Requests as class II devices and provided detailed classification regulations, including special controls, for such products going forward.
Reclassification of medical image analyzers and associated software
FDA reclassified from class III (premarket approval) to class II (premarket notification with special controls) certain radiological medical image analyzers, including computer-assisted/aided detection (CADe) devices for mammography breast cancer, ultrasound breast lesions, radiograph lung nodules, and radiograph dental caries detection. The reclassified device type (regulated under product code MYN) is intended to direct clinicians’ attention during interpretation of a radiology image to portions of the image that may reveal abnormalities. Device manufacturers are no longer required to submit a premarket approval application (PMA) for these devices and, instead, the devices are now subject to 510(k) premarket notification. FDA also confirmed the special controls that the agency believes are necessary to provide a reasonable assurance of safety and effectiveness of the CADe device type.
The order is published at 85 Fed. Reg. 3545 and finalizes a proposed order from 2018. The reclassification is codified at 21 CFR 892.2070. The order will be effective 21 February 2020.
In addition, the associated final guidance provides detailed information regarding clinical performance assessment studies for CADe devices applied to radiology images and radiology device data and CADe devices applied to mammography breast cancer, ultrasound breast lesions, radiograph lung nodules, and radiograph dental caries. See Clinical Performance Assessment: Considerations for Computer Assisted Detection Devices Applied to Radiology Images and Radiology Device Data in Premarket Notification (510(k)) Submissions. This guidance was previously in draft form since 2012 and the updates to it are minor to reflect the appropriate product codes and regulatory pathway. The prior information regarding clinical performance assessment studies for CADe devices in the guidance remains largely unchanged.
Two prior De Novo Request classifications codified
On a related note and in an effort to define the differences between various CAD software device types, the agency simultaneously announced the codification of two prior De Novo request classifications for class II CAD software devices. FDA previously granted De Novo Requests from sponsors for classification into class II for the QuantX (CADx) and ContaCT (CADt) devices.
With these orders, the agency has formally added two new device classification regulations:
“Radiological computer-assisted diagnostic (CADx) software for lesions suspicious of cancer” (21 CFR 892.2060) is intended to aid in the characterization of lesions as suspicious for cancer identified on acquired medical images such as magnetic resonance, mammography, radiography, or computed tomography. Diagnostic and patient management decisions are made by the clinical user.
“Radiological computer aided triage and notification software” (21 CFR 892.2080) is intended to aid in prioritization and triage of radiological medical images. The device notifies a designated list of clinicians of the availability of time sensitive radiological medical images for review based on computer aided image analysis. The device does not mark, highlight, or direct users’ attention to a specific location in the original image.
Similar to CADe devices, FDA has determined that special controls, in addition to general controls, provide reasonable assurance of the safety and effectiveness of CADx and CADt devices as demonstrated by the prior granted De Novo Requests and subsequent use of the 510(k) pathway for CADx and CADt devices. The necessary special controls for each device type (CADx and CADt) appear in the associated regulations codified by this order. Design verification and validation requirements include details of the image analysis algorithms, performance testing, and software documentation. For CADt devices, FDA has emphasized the need to meet the special control of effective triage whereas the special controls for CADx devices focus on the possible false positive and negative results from a diagnostic device. It will be important for device manufacturers to correctly identify their CAD software device type and to focus on the agency’s provided special controls for CADe, CADx and CADt software devices, respectively.
Conclusions
These classification regulations and guidance document provide clarity and help ensure consistency in the regulatory standards and data requirements required to support 510(k) notices for these types of radiological analysis software devices. As innovation in this area continues, companies should look to these defined special controls and engage with FDA regarding the necessary studies to support clearance.
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