Stereotactic Breast Imaging - Detailed Proposal - 2012-2013

1. Proposed Profile: Stereotactic Breast Imaging

• Proposal Editor: Janet Keyes (WG 15 industry co-chair)
• Editor: Janet Keyes (WG 15 industry co-chair)
• Other Contributors: DICOM WG 15, including Dr. Judith Wolfman (clinical co-chair)
• Domain: Radiology

Summary

It is challenging for radiologists to review images resulting from stereotactic breast imaging procedures on non-modality workstations after the procedure is complete.

DICOM provides attributes in the Digital Mammography X-Ray Image IOD that can be used to exchange information for optimal visualization of the images on non-modality workstations.

A Stereotactic Breast Imaging profile could define actors and transactions that specify how to record and use the necessary information for optimal visualization of the images on non-modality workstations.

Radiologists that consult on stereotactic breast imaging procedures after completion, e.g., to provide a second opinion, are willing to participate in Profile development.

Given experience with the improvement of mammography image display on non-modality specific workstations based on the IHE Mammography Image profile, IHE seems the natural vehicle to use to achieve improvement of stereotactic breast image display on non-modality workstations.

2. The Problem

Stereotactic Breast Imaging is a technique using “stereo” pairs of X-ray exposures acquired at predetermined angles to one another for a radiologist (breast imaging physician) to ascertain the proper placement of breast biopsy instruments. Review of the images (2D projections) as related pairs is critical to determining the target tissue’s 3rd dimension (“Z coordinate”), providing the radiologist’s confidence in the accurate placement of the biopsy instrument, and in the effectiveness in removing the correct target tissue.

Currently, only the vendor-dependent acquisition stations for the Stereotactic imaging systems permit selection and display of image pairs. Lack of DICOM header information currently results in limited ability to archive the necessary information and to optimally visualize these images on downstream workstations, with respect to hanging protocols, image enhancement, and targeting information.

Users desire interoperability between Acquisition Modalities, Image Manager/Archives and Image Displays.

The stereotactic image data that is currently archived does not include all of the pertinent image identification including image orientation, sequencing of the stereo pairs, correct image processing from the acquisition, and target information. Radiologists or physician consultants who are reviewing stereotactic images on non-modality workstations after the procedure, e.g., for a second opinion or patient management, must manually hang the stereo pair images without benefit of annotation of the paired sequence, and cannot view targeting information or image enhancements performed at the modality. Radiologists must take additional time, and do not have optimal access to all the desired information to complete the task.

3. Key Use Case

• A patient is scheduled for a Stereotactic Breast Biopsy procedure for the extraction of a suspect mammographic abnormality (e.g., microcalcifications).

• During the procedure, the technologist acquires stereotactic paired digital mammography images on the modality at prescribed plus and minus angles to a scout image.

• The radiologist utilizes these images on the modality to determine the location coordinates for introduction of a biopsy instrument and extraction of tissue from the site of abnormality.

• Additional stereo paired images are obtained to confirm needle positioning, subsequent placement of a tissue marker, and documentation of successful extraction of the targeted tissue. These image pairs are commonly referred to as “Scout”, “Pre-fire Plus / Minus”, “Post-fire Plus / Minus”, “Post-biopsy Plus / Minus”, “Post-marker Plus / Minus”, and single Post-biopsy or Post-marker images.

• After the procedure is completed the images are archived.

• If there is subsequent question as to the accuracy of removal of the targeted abnormality, a radiologist needs to be able to view these images on a non-modality workstation for problem-solving and/or second opinion. In order to provide for second opinion at a non-performing institution, optimal digital data is currently not available for transfer and display.

• In order to maintain a record of the procedure and its outcome, one current known workaround is to print the stereo paired images on a film printer from the modality, where the film contains the targets and image enhancement.

• The films are scanned into DICOM Secondary Capture Images and archived on a PACS and are available for review on a workstation, with some degradation to the information due to scanning.

In image instances stored to external devices, the modality should record the information identifying the stereotactic images (“Scout”, “Pre-fire Plus / Minus”, “Post-fire Plus / Minus”, “Post-biopsy Plus / Minus”, “Post-marker Plus / Minus”) and the correct patient orientation of the stored pixel data. In addition, the modality should record the targeting information and image enhancements applied at the modality.

The non-modality workstation should use the information provided in the stored image instances for automatic hanging (including orientation) of stereo paired images, and display of targeting information and image enhancements.

4. Standards & Systems

DICOM PS 3.3, A.27 Digital Mammography X-Ray Image IOD.

DICOM PS 3.3, C.8.11.7.1.4 Image Type (of the Mammography Image module), where Image Type (0008,0008) Value 3 records the information identifying the stereotactic images.

DICOM CP-xxxx (pending submission): Add optional attributes to record targeting information to the Mammography Image module of the Digital Mammography X-Ray Image IOD.

Systems involved/affected: Modalities that are used to perform stereotactic biopsy procedures, non-modality review workstations that are used to display resulting images after the procedure.

5. Technical Approach

Existing actors

Acquisition Modality, Image Display, Image Manager / Image Archive

New actors

None

Existing transactions

4.8 Modality Images Stored: Extend by adding paragraphs to specify attributes that the Acquisition Modality is required to record in Stereotactic Breast Images using the existing Digital Mammography X-Ray Image Storage – For Presentation SOP Class, similar to 4.8.4.1.2.3 Storage of Full Field Digital Mammography Images:

• Image Type (0008,0008) Value 3, according to DICOM PS 3.3, C.8.11.7.1.4.

• Referenced Image Sequence (0008,1140): A paired image shall reference the corresponding image in the pair (minus references plus, and vice versa).

• Patient Orientation (0020,0020): shall correctly identify the orientation of the stored pixel data

• Biopsy Target Sequence (gggg,eee1): DICOM CP in progress to add the necessary attributes to the Mammography Image module.

• The Acquisition Modality shall provide the opportunity to store image pixel data that includes user applied image enhancements (e.g., sharpening, smoothing).

4.16 Retrieve Images: Extend by adding paragraphs that specify how the Image Display is to use attributes from the Modality Images Stored transaction for optimal display of Stereotactic Breast Images, similar to 4.16.4.2.2.1.1 Display of Digital Mammography Images:

• Use Image Type (0008,0008) value 3 and Referenced Image Sequence (0008,1140) to identify paired images to configure to hang side-by-side automatically in defined hanging protocols.

• Use Patient Orientation (0020,0020) to orient the images per user preference (e.g., chest wall on top, bottom, left or right).

• Make the content of Biopsy Target Sequence (gggg,eee1) available for display.

New transactions (standards used)

None

Impact on existing integration profiles

None

New integration profiles needed

Stereotactic Breast Imaging profile, patterned after the Mammography Image profile.

The Stereotactic Breast Imaging profile specifies how DICOM stereotactic breast images are created, exchanged and used. It describes how Acquisition Modalities transfer the images, and how Image Displays would retrieve and make use of the images. It defines the basic display capabilities Image Displays are expected to provide, and which attributes should be used to implement those capabilities.

Managing the process of creating, storing and using Stereotactic Breast Image content is similar to workflow for other image content (e.g., see Scheduled Workflow, Mammography Image Profiles).

The Stereotactic Breast Imaging Profile is designed to provide faithful and complete storage and retrieval of stereotactic breast imaging data and sufficient display to allow optimal visualization of images for the purpose of consultation or second opinion. It does not address the use of other modalities appropriate for breast imaging such as MR or US.

Breakdown of tasks that need to be accomplished

• Profile description for IHE Radiology Technical Framework vol 1
• Obtain input from affected radiologists to ensure the Acquisition Modality and Image Display requirements are sufficient to produce the desired outcome of optimal visualization
• New transaction requirements for 4.8 and 4.16 in IHE Radiology Technical Framework vol 2

6. Support & Resources

DICOM WG 15, affected radiologists

• the key stakeholders/experts are already convening under the umbrella of WG-15 and agree to do the primary development work there.

7. Risks

Acquisition Modality and Image Display implementers may not add support for the profile if they do not perceive sufficient customer demand to make it a priority.

8. Open Issues

• How much of the existing IHE Mammography Image profile requirements in transactions 4.8 and 4.16 should be required for the Stereotactic Breast Imaging profile?

• Pending DICOM CP to add new optional attributes to record targeting information. DICOM WG 15 will submit this for the Nov 5 WG-6 meeting and track it's progress.

9. Tech Cmte Evaluation

Effort Evaluation (as a % of Tech Cmte Bandwidth):

• 20% given that WG-15 will complete the consensus/authoring prior to Rad TC meetings which will mostly just review the material.

Responses to Issues:

See italics in Risk and Open Issue sections

Candidate Editor:

Janet Keyes (w Paul Morgan as F2F editor)