Re: Reading DICOM tag's from the DICOM file before loading the image data

Hi there, I tried to do this using the DicomDataSet class, however I found that the Load method still tried to load the image data (well, that's what I assume was happening as each 50mb DICOM file I enumerated took around 10sec to load, while smaller DICOM files had a much faster load time).

Is it possible to just look for a particular tag in the file without loading the image data (so i can determine whether I need to load the image data or not!)? I only need to know if the tag is present, not it's value.

I'm using Leadtools v15 with C# .Net.

This is only possible with a small number of tags, which are
detailed in the help topic "DICOM File Comments" in the main API help
file. For these tags, you can use the LEADTOOLS Read Comment function instead of the LEADTOOLS DICOM functions.

Unfortunately, it's a private tag I'm trying to read so I'm sure the Read Comment function won't work for me. Is there no other way?

I'm afraid that the only way to read private tags is to load the entire data set.

Dear Yasir,

with version 14.5 and 14.0 we had a DicomDS Com-Object. Using that COM component, we could simply use the LoadDS() method. That was lightning fast. After that, you could freely browse through the dataset. Unless you didn't call the GetBitmapValue() method, there was absolutely no performance issue. I would definitely need a workaround. The current implementation is unusable for us. Imagine, we have 100 micron Dicom images with up to 120 MB each. Impossible to implement performant code with the current approach.

Any idea?

Although any .NET application could be slower than its unmanaged counterpart, the difference should not that great.

 

Are you running your tests inside the Visual Studio .NET
debugger? If yes, this could dramatically slow things down because of the way
Visual Studio loads our DLLs. Please try to make a Release build of your application and test it outside the debugger to see if this is the cause of the delay.

Unfortunately, the behaviour is exactly the same regardless of whether the code is run in Debug or Release mode.

I want to test this myself and see if I can ask our engineers to do any changes in the toolkit. Can you send me 3 things:

1. A sample DICOM data set that can be used to show the problem.

2. A small V14.5 COM project (not your full application) that shows the fast behavior.

3. A small V15 .NET project (also not your full application) that shows the slow behavior.

 

If you want to send these files, please pack them in a ZIP
or RAR file and you can either post it here, or send it in an email to support@leadtools.com. Please mention this forum post if you choose the email option.

Hi Yasir,

I've uploaded two projects and some sample images to the LeadTools FTP site in the directory "/upload/FujiFilm/SlowDicomDataSet". The v14 COM project is written in Delphi, the v15 .Net project is written in C#.

The v14 project is a GUI app and gives you a file browser to the images, the v15 project is a console app and uses a hard-coded path to a directory containing DICOM files. There is a code comment at the top of the main class in this project letting you know what to set the path to.

Thanks for looking into this,

Josh.

Thank you so much for that! I believed I was gaining by passing LoadAndClose since I wasn't holding an open file handle, however I guess if you pass that parameter the DicomDataSet class must load the whole file into memory to acheive it's goals. Once I modified my code to pass None it worked wonderfully.