3D/4D Echo White paper - List of use cases

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List of 3D/4D Echo use cases

Below is an initial list of clinical use cases for which 3D/4D Echocardiography is relevant. For each use case there will be a high level description, some basic steps, and open issues. At this point in time this is meant to be a starting point for discussions rather than detailed clinical use cases.

In the context of this whitepaper we will be focussing on interactions between the sonographer at the scanner and the reading physicin at a review workstation. The overall clinical workflow (including patient admission, ordering, scheduling, image acquisition, storage and reporting) is covered in the Echo workflow and will be most likely the same for 3D/4D Echo workflow, actually most likely it will be the same, since all studies will include 2D and 3D objects. The critical part for 3D/4D workflow is on the review of the 3D/4D datasets and the interaction with the volume data.

Generic Echo use case

In clincial routine, there will be no specific 3D Echo use cases, a general Echo exam will consist of 2D image data as well as of volume data. Therefore the generic use case will be described here and links to use cases for specific volume workflows provided. Again, this use case will only cover the interactions between acquisition modality, evidence creator, Image Manager/Archive and Image Display. For all other actors please refer to the Echocardiography workflow.

Basic steps:

  • On the scanner:
    • User claims a work item and start the corresponding exam
    • The user performs some of the following steps in the site specific order
      • optimizes settings and performs 2D acquisition of anatomy/morphology of interest using one of the following techniques:
        • B-Mode
        • B-Mode with color flow
        • M-Mode
        • CW
        • PW
        • ...
      • optimizes settings and performs a volume acquisition of anatomy/morphology of interest using one of the following techniques:
        • B-Mode
        • B-Mode with color flow
        • ...
      • performs measurements during data acquisition
      • performs volume stress echo acquisition
    • System stores images and measurements locaclly. For volume data the ECG is stored in a separate object and linked to the volume
    • User reviews acquired objects, performs additional measurements and manipulates volume data:
      • performs 3D quantification use case
      • performs visualization of valvular or congential disease use case
      • performs volume contrast echo use case
      • performs fetal stress echo use case
      • performs volume stress echo use case
    • Systems stores all additional images, derived views, measurements locally
    • User ends the exam
    • User either sends the study manually to PACS or system automatically forwards the study to the archive
  • At the workplace:
    • User or system intiates retrieval of study from archive
    • User opens study and reviews images, views and measurements done by the sonographer on the scanner:
      • performs 2D review (as usual)
      • performs 3D quantification use case
      • performs visualization of valvular or congential disease use case
      • performs volume contrast echo use case
      • performs fetal stress echo use case
      • performs volume stress echo use case
    • Systems stores all additional images, derived views, measurements locally
    • User ends the exam
    • User either sends additional images/views/measurements manually to PACS or system automatically forwards the study to the archive

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3D Quantification of chambers

It is proven that 3D quantification of the cardiac chambers is more accurate and reproducible for multiple reasons:

  • No geometric modelling is necessary
  • Improved endocardial visualization

Parameters to be quantified:

  • LV ejection fraction
  • LV mass
  • LA and RA volume
  • RV volume
  • Note: are there additional parameters which have not conventionally been used on 2D

Basic steps:

  • On the scanner:
    • User queries modality worklist and selects patient/procedure
    • User acquires a volume clip together with the associated ECG waveform
    • System stores the volume clips and associated ECG locally
    • User opens volume into review
    • system displays volume data synchronized with external ECG waveform
    • User performs chamber quantification
    • System saves measurements and calculations in DICOM comprehensive SR (TID 5200 or 5300) and marks them as 3D measurments.
    • User archives study to the local PACS system
  • At the review workstation
    • User retrieves study and opens it
    • User selects a volume and opens it
    • System displays volume synchronized with external waveform and measurements.
    • User reviews volume data and measurements
    • User performs additional measurements and derives some more views of the volume.
    • User ends study and stores additions back to the archive
    • User reviews volume data and measurement data

Open issues:

  • workflow must accomodate for manual, semi-automated, and automated methods to calculate chamber volumes. Depending on the method used, different requirements for derived views (and therefore presentation states) may apply (eg what is the starting point for manually tracing views or for semi-automated algorithms? Are spefic views needed, if so I assume it should be based on MPRs of standard views.)
  • Are there additional volume measurements which do not exist currently in 2D Echo
  • How are 3D measurements encoded (3D modifier?)
  ==> for measurements existing already the following mapping can be used:
      Image Mode: DCM 125231 3D mode 
      Echocardiography Volume Method : DCM 125206 Cube method
  • Annotations inside of image
  • How are quantification results displayed?
    • just as numbers in reporting package
    • MPR views with outline of segmented cavity
    • Volume rendered view of segmented cavity with/without surrounding tissue
    • 16/17 segment model in 3D

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Visualization of valvular or congential heart disease

The advantages of using 3D Echocardiography for visualizing valvular heart disease are

  • quantification of the mitral anulus
  • visualization of mitral leaflets, commisures and orrifice
  • perpendicular en-face views enable accurate valve area measurements
  • support of surgical planning
  • more accurate quantification of mitral and aortic stenosis
  • 3D color flow imaging combined with grayscale data for analysis of jets (origin, direction , orrifice areas, flow measurements ...)
  • Visualization of complex cardiac anatomy of congenital defects
  • perpendicular en face view of septal defects for determinig size

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Volume Stress Echo

  • Fast volume acquistion at different stress levels, wall motion analysis based on MPRs for standard views

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Interoperative 3D Echo

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Volume Contrast Echo

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Fetal Volume Echo

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