Friday, July 23, 2010

Development of a DICOM Structured Report Viewer for IRMACON

For diagnosing in Radiology it can be very helpful to examine similiar pictures with regarding results, comparing them to the new one. This way a second opinion to the current results can be obtained. IRMA (Image Retrieval in Medical Applications) implements a similarity search based on a given PACS (Picture Archiving System). Within the scope of the project IRMACON, IRMA is integrated exemplarily into radiologic routine for any given CBIR-systems. The results of the similarity search are being processed into DICOM Structured Reporting Documents (SR) by an Evidence-Creator, realized in a diploma thesis. The DICOM SR contains information to source and resulting pictures as well as patient and device data. Picture data can also exist in form of Region of Interest (ROI) if similarities should be compared only for a specified area of the given picture. SRs are based on a defined template, which specifies the structure and value types.

jansen_en_detail[1] In the context of this student research project a web based viewer for SRs is to be realized, which allows displaying SR data, given in binary format, with all relevant information (source and resulting pictures, patient and device data, Regions of Interest). To be independent of any given PACS, the viewer contains several possibilities of displaying pictures, which are linked within the SR.

1) On the one hand, pictures can be directly loaded and displayed from the DICOM-PACS. Because DICOM pictures cannot be displayed directly by a webbrowser, they need to be converted into a compatible format. This is achieved by the use of the DICOM OFFIS Toolkit (DCMTK).

2) On the other hand, IRMA uses a matching database for the similarity search, which matches DICOM-IDs to corresponding IRMA-IDs (since the search works on PNG-files). So pictures, referenced with their DICOM-IDs from within the SR, can be loaded from the IRMA-DB. This way we do neither need to access the DICOM-DB nor need to convert the DICOM binary format. Though IRMA-DB access is done by the Evidence Creator.

The viewer is also to be entirely integrated into the IRMA framework and is based, to some amount, on its components. The whole project is developed in PHP so results can be generated dynamically during runtime. The single steps needed to display a SR are:

  1. Download SR from the DICOM-DB, with its unique DICOM-ID given as a parameter
  2. Converting the SR into a XML-file using OFFIS DCMTK
  3. Parsing the XML-file using Xerces
  4. Transforming the XML data into an HTML-file using PHP
  5. Downloading pictures as described above
  6. Displaying ROIs for given pictures, if available

Schedule: since 08/2009

arranged by: Sebastian Jansen

supervised by: Dipl.-Inform. Petra Welter

Read More

No comments: