Currently, image exchange portals (IEPs) are the national vendor-neutral solution for sharing radiology images in a multivendor environment -- at least in the U.K. Radiology image exchange happens irrespective of the PACS vendor. The PACS community is working together to make this exchange possible, but can vendors really collaborate effectively?
IEPs have been successfully implemented in England, where there is a multivendor PACS environment. All vendors support the DICOM C-Store standard to make IEP interoperability feasible. A multivendor environment of PACS enables healthy competition and reduces costs to a public-funded National Health Service (NHS).
However, IEPs consist of a push-based model for sharing images and reports. Whilst "push IEPs" can be very useful, they have limitations because they require prior knowledge of what exists in other PACS destinations for the patients. Hence, there is now a need to modernize to a query- or access-based model for sharing for both images and reports -- as described on page 26 of the 2016 guidance document on DICOM-based vendor-neutral indexes from the U.K. Royal College of Radiologists (RCR).
Adopting a query- and access-based approach has some potential benefits. It can save time for radiologists and other doctors because they will have access to images instantly, rather than having to request them via the current IEPs. It can also save time for administrative staff because manual processes for IEP transfers will be reduced as more hospitals adopt IEP 2. At my hospital in Doncaster, around 30 hours a week of administrative staff time is spent on IEP processes.
Lower radiation dose to patients can occur due to fewer unnecessary duplicate examinations. Further, radiologists can provide more accurate reports for patients due to instant access to prior images and reports held in other organizations by a cross-enterprise timeline (on their local PACS).
Challenges for industry
Improving image sharing requires vendor collaboration on vendor-neutral standards of DICOM. In the U.K., the challenges to the PACS community related to sharing are as follows:
- Can the current IEP vendor (Sectra) invest to modernize the national sharing solution to a DICOM-based vendor-neutral index (VNI)? Are other national vendor-neutral DICOM indexes available that can serve as an alternative to Sectra's IEP? If so, how quickly can they be made available as a national solution?
- Are PACS vendors willing to collaborate with a national vendor-neutral DICOM index (Sectra or any other vendor) using the DICOM C-Find or DICOM C-Move standards? Also, can PACS vendors treat these images moved from another hospital differently from those permanently archived? Can the images be purged after two weeks, knowing that they are permanently archived elsewhere, thereby creating a temporary PACS to house the regional images moved for display?
- Will radiologists be able to see a regional/national patient timeline for radiology exams on their local PACS viewer? PACS needs to support a DICOM C-Find query of its local PACS DICOM directory and also the national DICOM index to populate the PACS timeline for the patient. Will radiologists be able to view images and reports on their local PACS viewer, even though the images lie on a different PACS, which is moved using DICOM C-Move? Will the PACS vendor support a DICOM C-Move trigger from a radiologist's PACS viewer?
- To mitigate any information governance concerns, will the local PACS keep a full, auditable access log for patient image and report access, even though some of the images may not be local within its own archive?
The RCR had a very positive dialogue with industry on this concept in March 2019. The PACS industry understood the issues and was keen to support radiologists having regional access to images and reports on their local PACS viewers.
Practical implementation remains elusive, and we still need to see some real-world pilot projects between PACS and VNI vendors. For instance, vendors need to install a DICOM VNI for a region. They must be able to receive HL7 admission, discharge, and transfer (ADT) feeds from hospital A and hospital B, and receive HL7 ORM (order) and ORU (observation) feeds from hospital A and hospital B. Also, they need to support DICOM C-Find queries from PACS A and PACS B and receive and forward DICOM C-Move queries to the appropriate PACS.
For PACS A and B, it is important to support DICOM C-Find queries to VNI -- to populate the patient imaging timeline. Another consideration is the PACS viewer-display patient timeline from the local PACS archive, but also the information in the VNI. If the user wishes to display images, it should trigger a C-Move query to the VNI, which then forwards it to the appropriate PACS. Images from other hospitals are temporarily stored in a quarantine/temporary folder in PACS and purged after a month. Audit trails for viewing are required.
Dr. Neelam Dugar is a consultant radiologist at the Doncaster and Bassetlaw Teaching Hospitals National Health Service (NHS) Foundation Trust, U.K., and informatics adviser to the Royal College of Radiologists (RCR). This article was written in her personal capacity, and her views and ideas are not necessarily shared by the RCR.
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