Mammography CAD Workflow - Brief Proposal

1. Proposed Profile: Mammography Acquisition and CAD Workflow

• Proposal Editor: Carolyn Reynolds
• Date: N/A (Wiki keeps history)
• Version: N/A (Wiki keeps history)
• Domain: Radiology

2. The Problem

There are common practices in mammography which can have a wide variety of workflow results. Even when deploying the Scheduled Workflow and Mammography Image Profiles, variances in the way users and systems behave can lead to department inefficiencies, ambiguous data, special cases for automated billing, and less than optimal acquisition and reading environments.

Below are just a few examples of such concerns:

Additional Views

Radiologists often request retakes or additional views after the initial imaging service is completed. Doing so can lead to some of the following issues:

• Additional views may effectively change the type of the exam (i.e. screening to diagnostic, or uni-lateral to bi-lateral). The resulting final exam type is not evident to systems and users.

• Using another study or accession number to add the views leads to archiving, billing, and display presentation problems.

• Some workstation behaviors are incompatible with the needs of mammography, such as not allowing the addition of images to studies that are open or have already been viewed.

• Additional views can be mistaken for complete prior exams.

CAD Processing and Workflow Race Conditions

• CAD systems do not know precisely when to start and stop case level processing and exactly what objects should be considered for processing. Common practice uses a timeout strategy which has its own issues.

• Race conditions between image and CAD availability can bring about reading inefficiencies.

• Additional views complicate case level processing and can result in multiple CAD reports, leaving the workstation and radiologist uncertain as to which CAD report(s) to view.

Determining Exam Completion

• Because additional views (both on the day of the study and at a later time) are common practice and other objects (annotations, CAD results) can be added to studies at a later time, it is difficult for both users and systems to determine when a patient exam is actually complete. Many systems have implicit ways of treating exams as complete or open which can conflict with the actual state of the mammography exam.

Correcting Mistakes

• A common problem for technologists is the incorrect labeling of views. When the view is corrected at the acquisition modality and resent, the corrected view may appear as a separate study with a different accession number.

3. Key Use Cases

Some use cases can be inferred from the description of the problems above. Other use cases are available, but are omitted in the interest of brevity.

1. A patient comes in for a screening mammogram which is converted to a diagnostic exam upon the technologist discovering a lump. The tech adds an extra view, but no exam type, so the hanging protocol at the workstation is unacceptable.

2. A patient comes in for follow-up in one breast. Since she is close to her yearly exam date, the radiologist calls for imaging the other breast while the patient is waiting. The original room is unavailable, so another machine is used. The tech generates a new study and accession number. The right and left breasts do not hang together at the diagnostic workstation. The following year, the prior images are hung as two prior studies, not as one complete comparison study.

3. A radiologist views a screening exam and toggles on CAD which shows findings. The radiologist requests additional images to better demonstrate the abnormality. Should the tech add the views to the existing order? Does it depend upon whether or not the patient is still available for imaging that day? How should the exam type (and billing) change from screening to diagnostic if this is necessary?

4. The technologist labels a view incorrectly and doesn’t realize it until after the case is completed and sent to PACS. The view information is corrected at the acquisition modality and the view resent. The images do not hang properly on the workstations and multiple copies of the same image exist, one which is labeled incorrectly.

5. A PACS will not distribute images until a study is complete. A technologist wants the radiologist to view the images before completing the exam. The radiologist can not access the images from the local workstation.

4. Standards & Systems

Existing standards and mechanisms to consider include:

• DICOM

• Existing IHE profiles, actors, and transactions

Existing systems that could be involved in the problem/solution include: FFDM modalities, Mammography CAD servers, Diagnostic and Technologists’ workstations, PACS, and RIS.

5. Discussion

The Topic “Mammography Acquisition and CAD Workflow” is currently a catch-all topic for issues related to the workflow of ordering, acquisition, processing, archiving, display, and billing for mammography procedures. Upon further investigation, the IHE Mammography committee may further refine the scope of this proposal to keep aligned with the time and resources available to deliver viable solutions to specific use cases.

IHE is a great forum to consider solutions to these clinical challenges. The challenges with additional views might be solved by defining how to apply more generalized scheduled workflow use cases to mammography practices. Where existing profiles may not meet mammography departmental needs, it is believed that the IHE venue may be able to identify other solutions or identify gaps in technology that could be handed off to the appropriate resources (i.e. DICOM committees).

The IHE Post Processing Profile has been discussed as a candidate for mammography CAD workflow. An effort into understanding why this profile has not been adopted and addressing barriers to its adoption could lead to agreeable solution (or a more viable profile) among the mammography community without waiting for the greater radiology community to adopt the already existing profile.