Presentation of CAD/Annotations/Markups - Detailed Proposal: Difference between revisions

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New page: ==1. Proposed Workitem: == * Proposal Editor: Michael Planchart/Peter Maton * Domain: Radiology ==2. The Problem== Advanced image processing algorithms (e.g. Soft tissue or bone suppres...
 
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==2. The Problem==
==2. The Problem==


Advanced image processing algorithms (e.g. Soft tissue or bone suppression, temporal subtraction) are being developed by various medical software companies.  These algorithms provide various outputs that enhance the source images obtained directly from the modalities.
CAD and clinical processing applications create processed images with annotations/markups. Different products are using different mechanisms for the markup, e.g.:


As more post processing algorithms become available and more combination of outputs are possible the practicality of generating and storing all possible output images rapidly decreases.
:*burned into the DICOM image,


A more practical approach is to generate the required output on demand invoking only the required algorithms, or possibly using pre calculated intermediate results, and only creating the requested output combinations.
:*encoded in the image overlay,
 
:*encoded in separate presentation state graphics,
 
:*encoded in a separate SR,
 
:*rendered onto the image in a separate JPEG
 
With so many mechanisms, display systems support some of them poorly or not at all, so workflow is disrupted and key information may be inaccessible.
The variability also makes it very difficult to create robust hanging protocols.
 
Of all the methods available the DICOM Structured Report (SR) is the preferred one and by industry-wide consensus, to contain the encoded markups.


==3. Key Use Cases==
==3. Key Use Cases==


*'''On-Demand Request of Advanced Processed Images:'''
*'''DR/CR Chest X-Ray Lung CAD:'''


A radiologist reading a patient case would select additional computed information from a list of available processing options and parameter settings using GUI element definitions provided to the viewing workstation application by the computation server. This request would be processed via HTTP/HTTPS to the WADO sub-system of the Dynamically Computed Image Server.  By means of a server side script the requested images would be fetched and/or processed according to the request and the resulting images and/or DICOM annotation/markup objects would be sent back to the PACS image viewing workstation.
Chest X-Ray Lung CAD devices process the digital images of AP/PA projections (frontal chest) obtained from the DR/CR modalities in order to detect nodules or abnormalities and to identify and mark the coordinates of the regions of interest (ROI).  
 
The CAD processed output shall be delivered as a DICOM Chest CAD SR SOP Class to the PACS server.
 
The PACS image viewing workstation shall provide the means of toggling on off the markers atop the source image.  The markers should be off by default on the PACS viewing workstation.  The SR should be independently toggled from other overlays.


==4. Standards & Systems==
==4. Standards & Systems==
*DICOM – Chest CAD SR SOP Class


*DICOM – Web Access to DICOM Persistent Objects (WADO)
==5. Discussion==
*DICOM – Hanging Protocols
*DICOM – Post-Processing Worklist
*HTTP and HTTPS


==5. Discussion==
IHE has proven to succesfully develop profiles that harmonize the DICOM and HL7 standards to solve many integration problems where vendors were using disparate approaches.


DICOM has defined a standard that could be leveraged for On-Demand services: Web Access to DICOM Persistent Objects (WADO).
A profile based on this proposal would allow vendors to implement the same functionality accross the board.


Since computation servers will provide different capabilities with various associated parameters a general mechanism is required for the server to specify the selection mechanisms including the types of GUI elements to be used by the workstation client.
The profile would be tested during Connectathons to validate DICOM compliance.

Revision as of 08:40, 17 September 2009

1. Proposed Workitem:

  • Proposal Editor: Michael Planchart/Peter Maton
  • Domain: Radiology

2. The Problem

CAD and clinical processing applications create processed images with annotations/markups. Different products are using different mechanisms for the markup, e.g.:

  • burned into the DICOM image,
  • encoded in the image overlay,
  • encoded in separate presentation state graphics,
  • encoded in a separate SR,
  • rendered onto the image in a separate JPEG

With so many mechanisms, display systems support some of them poorly or not at all, so workflow is disrupted and key information may be inaccessible. The variability also makes it very difficult to create robust hanging protocols.

Of all the methods available the DICOM Structured Report (SR) is the preferred one and by industry-wide consensus, to contain the encoded markups.

3. Key Use Cases

  • DR/CR Chest X-Ray Lung CAD:

Chest X-Ray Lung CAD devices process the digital images of AP/PA projections (frontal chest) obtained from the DR/CR modalities in order to detect nodules or abnormalities and to identify and mark the coordinates of the regions of interest (ROI).

The CAD processed output shall be delivered as a DICOM Chest CAD SR SOP Class to the PACS server.

The PACS image viewing workstation shall provide the means of toggling on off the markers atop the source image. The markers should be off by default on the PACS viewing workstation. The SR should be independently toggled from other overlays.

4. Standards & Systems

  • DICOM – Chest CAD SR SOP Class

5. Discussion

IHE has proven to succesfully develop profiles that harmonize the DICOM and HL7 standards to solve many integration problems where vendors were using disparate approaches.

A profile based on this proposal would allow vendors to implement the same functionality accross the board.

The profile would be tested during Connectathons to validate DICOM compliance.

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