Quantitative imaging guidance arrives for OEMs from FDA
The FDA has issued final guidance for medical imaging manufacturers seeking the agency’s approval of devices with functionality for quantitative imaging.
Defining quantitative imaging as any medical imaging that acquires not only images and image data but also numerically expressed values, FDA lists as examples standard uptake values (SUVs) in nuclear medicine, volumetry measurements in tomographic CT and MR imaging, and relaxometry (T1 or T2 values) in MR.
“Quantitative imaging values are usually subject to both systematic error and random variation,” the guidance points out. “Thus, a quantitative imaging value can often differ from the true value of the measurand (the quantity being estimated). Systematic errors and random variation in quantitative imaging impact the reported outputs and may affect clinical decision making.”
The document offers manufacturing stakeholders and other interested parties some common sources of error to consider when planning or conducting quantitative imaging exams. Sample sources include:
- Patient Characteristics
- Demographic (e.g., patient age, gender, race)
- Physiological (e.g., weight, heart rate, body temperature)
- Temporal variability in the measurand (e.g., lesion shape, size, location, blood oxygenation)
- Image Acquisition
- Patient positioning and preparation during image acquisition
- Imaging hardware (manufacturer, model, software version) of the imaging device
- Image acquisition protocol (e.g., MR sequence and timings; x-ray dose; amount, type,
- Image Processing
- Algorithm specifics (e.g., filtering, software version, database selection)
- User interaction (e.g., manual segmentation, seed point selection)
- Non-deterministic algorithm (e.g., curve fitting for dynamic contrast enhanced MRI exams)
The document also walks the reader through three categories of information FDA will expect to see detailed in any premarket submissions.
In general, the agency states, manufacturers preparing premarket submissions for radiological devices that include quantitative imaging functions should “provide performance specifications for the quantitative imaging functions, supporting performance data to demonstrate that the quantitative imaging functions meet those performance specifications, and sufficient information for the end user to obtain, understand and interpret the values provided by the quantitative imaging functions” (emphasis added).
FDA also notes:
The contents of this document do not have the force and effect of law and are not meant to bind the public in any way, unless specifically incorporated into a contract. This document is intended only to provide clarity to the public regarding existing requirements under the law. FDA guidance documents, including this guidance, should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidance means that something is suggested or recommended but not required.”
The guidance arrives three years after FDA’s posting of the document’s original draft in spring 2019.
Full final guidance here.
Dave P. has worked in journalism, marketing and public relations for more than 30 years, frequently concentrating on hospitals, healthcare technology and Catholic communications. He has also specialized in fundraising communications, ghostwriting for CEOs of local, national and global charities, nonprofits and foundations.