New Device Classification Guidance published by GHTF: consequences for medical imaging software
The GHTF (Global Harmonization Task Force) issued a draft of a new guidance on medical device classification They recommend to implement four classes for medical devices based on intended use: from class A (lowest risk) to class D (highest risk). And they give a set of rules on how to choose the classification of the devices.
Comparison with regulations
Wait, I've already seen this elsewhere. Classification of devices in Europe (CE mark) and in Canada have systems very similar to what GHTF recommends. This is a good thing to have an ongoing harmonization process. National regulations copy what GHTF recommends and GHTF copies what national regulations require. This is a virtuous circle. Maybe one day the FDA will implement this classification system.
Let's dream of an harmonized world! By the way, the FDA has done a huge work
to classify the medical devices. Just have a look at their product
classification database and you will see that there are almost no shadow
zones, compared to the GHTF rules.
The main difference is that FDA has only 3 levels of classification, with very different paths to certification (premarket notification and premarket approval), compared to CE mark for example.
Classification of software
The document contains a definition of active medical devices, which includes software. And there is a paragraph in structure of the classification rules about how dealing with software: standalone, not standalone, software driving a device and so on. To sum-up:
- software are active devices,
- if they are not standalone, they fall into the category of the device they influence/drive/monitor/control,
- if they are standalone, apply the rules 9 to 12,
- the last rule (rule 12) is a fall-trough rule, which gives class A to every device, which doesn't match other rules.
No very different from CE mark or Canadian regulation.
Which classification for Medical Imaging Software?
Now let's have a closer look at Medical Imaging Software or PACS (Picture
Archiving Communication System). The GHTF gives samples for every rule. For
rule 12, you find: "powered equipment for the recording,
processing, viewing of diagnostic images". So every PACS and
standalone Medical Imaging Software are class A in the GHTF
Not only the viewers are class A but also software processing diagnostic images. Canada and CE didn't have those examples in their guidances. More, they issued notices about medical imaging software giving indications seemingly in contradiction with those of GHTF:
- The Canadian notice asserts that patient management software with capabilities beyond basic data visualization is considered a Class II medical device,
- The Manual on Borderline Classification in the EEC Regulatory Framework asserts that PACS which post-process the images without driving or influencing the source (i.e. CT, MRI, ultrasound) device and is intended to allow direct diagnosis is class IIa device.
I agree with CE and Canada guidances. Software post-processing images for
diagnosis shall be at level II, not level I. So I think that the samples given
by the GHTF should be redefined to match the CE and Canadian rules. The GHTF
rule 10(i) is about active devices for direct diagnosis. Inserting in the
samples the post-processing imaging software to allow diagnosis would be a
solution. This is not a big issue but it would clarify the situations of post
The harmonzation is ongoing but not for tomorrow!