OHIF DICOM Viewer - Measurements off?

[Chris Smith]

Hi all, 

I'm doing some testing with a number of our researchers using US scans and one of the researchers has noticed that the Annotated measurements are off in two different ways - 1) The magnitude is 10x larger than it should be and 2) Using the side markings for comparison, we're getting 1cm = 161mm.  

I have no clue where to even begin looking for anything that might fix this - I'd appreciate any help!

I've attached the XNAT Image with the Researcher's comments in text boxes so you can see what I'm seeing.

Thanks

Chris

[Chris Smith]

Forgot to mention we're running XNAT version 1.7.6, build: 1694 and OHIF-XNAT Viewer version 2.1.0....

Chris

[Chris Smith]

Hi all, 

Just to follow up as I'm getting a lot of pressure from the Research team to come up with solutions to these issues (from my original email which has a screenshot):

1) The magnitude is 10x larger than it should be and 

2) Using the side markings for comparison, we're getting 1cm = 161mm.    

The other question that has come up is how to purge all annotations from OHIF - either by a "Select all" | "Delete" by a user or via a script or some other automated process.  We are using XNAT for a blinded study and so each screener needs to see the same scans but cannot have any annotations on it when they're doing the review. 

Any direction or suggestions would be much appreciated.

Chis

[Simon Doran]

Hi Chris,

  Apologies not to have picked this up initially. I (and several others in the team, I think) was on an annual leave when you first posted.

  To the best of my knowledge, this part of the XNAT-OHIF viewer annotation framework is inherited from the core OHIF project and not something we have worked on directly. However, we will take a look. It would be extremely helpful if you could provide (either publicly via this discussion group) or privately an anonymised example dataset that we could use to reproduce your issue. Having just checked, I can certainly say with a high degree of confidence that the length measurements are not a factor of 10 off in MR, CT or PET, so it may be that there is a modality-specific issue here.

  Regarding your other query, support for blinded readings is something that we are keen to work on, as this is potentially a common use case where XNAT could be a very useful platform. In my view, purging the annotations is not necessarily the best idea in the long term,  but for the moment, you can achieve this goal by scripting a call to the ROI xapi, as shown below:

  Best wishes,

Simon