ASTP/ONC recently issued a Diagnostic Imaging Request for Information. Here are the questions, and my (personal) responses to them:
I'll start off by saying we are well beyond the time where this capability needs to be available to patients and providers in the national Health IT Infrastructure.
PM-1. What barriers do patients experience with electronic access to diagnostic images? Are there examples today where patients can successfully access, exchange, and use diagnostic images outside of a particular hospital or network system without use of physical media?
My son's partner had to travel an extra 20 minutes each way for imaging instead of going to the closed imaging center associated with a hospital from the same system (UMASS). More than a year after UMASS acquired this facility, there still was not imaging interoperability between the related facilities. It simply wasn't a priority b/c only the patient is inconvenienced. That's within the SAME hospital system. It's even worse between different systems.
I'm still in the habit of getting CDs (physical media) from imaging providers b/c of the lack of interop between facilities. I don't have this problem with my present provider network b/c they do focus on access between providers, but I've seen that even they have challenges when trying to get images from hospital imaging centers they work with.
PM-2. What existing policies do you believe limit or interfere with diagnostic image access, exchange, and use? What policies would you introduce to accelerate the transition to electronic, standards-based diagnostic image access and exchange and to reduce the practice of imaging silos that impede electronic access, exchange, or use of diagnostic images
- PM-2A. What other policy or financial barriers do providers face in accessing diagnostic images from outside facilities? For example, are there concerns about compliance with health care facility policies or procedures (e.g.,
security or overall policies on data sharing outside the facility), state laws, or malpractice liability?
Accessing prior imaging results reduces the financial compensation provided to specialty providers with their own imaging centers, by reducing the need for subsequent imaging, as several studies have shown (e.g., Outside imaging in emergency department transfer patients: CD import reduces rates of subsequent imaging utilization - PubMed)
- PM-2B. What technical/interoperability concerns exist, such as compatibility between systems, authorization issues from external sources, or issues with the provenance of diagnostic images?
The same study listed above indicates that 78% of images were able to be imported. I wrote in 2012 about Medical Imaging Exchange and referenced a study (no longer available on the web) that cited 80% import success. David Clunie (the acknowledged Father of DICOM) presented at RSNA in 2010 on the key reasons for import failures, failure to follow the DICOM standard, and presented a number of recommendations. While this report applied to images on media, the import failures over the internet will use the same standards in that report. The standards are available; they simply need to be followed.
PM-3. What technical, operational, and policy approaches can best support health care providers in transitioning from physical media ( e.g., CDs and DVDs) to secure, electronic exchange-based methods for sharing diagnostic images outside of their operating environment/health care organization system? If possible, please be detailed in your response.
The technical approaches should focus on XCA-I, which builds on the existing XCA standards used for National Networks and TEFCA today, DICOM for imaging, including some of the requirements about use of DICOM in the IHE Portable Data for Imaging and other related image sharing profiles, and commonly used metadata standards, with the incorporation of RADLEX for certain imaging metadata. The application of these technical and to some degree operational approaches (e.g., for metadata) build incrementally from already existing, widely support standards available for sharing of health information over the internet.
One key policy to consider is that image sharing challenges occur not just across health systems, but even within health systems. For a provider to be considered compliant (from a CMS rather than an ASTP/ONC perspective), imaging should be available electronically WITHIN and ACROSS the entire health system as well as from outside the system.
PM-4. Do health care providers and/or patients (including patient-facing apps) need access to the full resolution diagnostic images stored in PACS or is a reference image (
e.g.,
a DICOM image rendered as a JPEG) sufficient for clinical decision-making and use by health care providers and patients? Does this vary by clinician specialty or by type(s) of care provided to the patient? Please feel free to elaborate with rationale.
For the most part, for personal use, patients typically only need a reference image ... UNTIL they need to provide imaging access to another provider. At that point, the full resolution diagnostic image will be needed so that the consulting provider (e.g., for a follow-up or second opinion) may want access to the full resolution image.
Many ambulatory primary care providers likely only need access to a reference image, but specialty providers will definitely want full resolution diagnostic images so that they can use the imaging tools they have at hand to manipulate and view the image data.
Image exchange should enable both reference image access, and full resolution access to the imaging study to enable all use cases.
PM-5. Do health care providers and/or patients need access to quantitative parameters derived from images for clinical decision-making and use by providers and patients? Please feel free to elaborate with rationale.
Numerous quantitive parameters are useful for clinical decision support, and many also have specific places in the provider chart that enable provider workflows (e.g., in flowsheets and diagnostic results such as Cardiac ECHO and Stress Test).
SC-1. What technical approaches are currently in use to enable access and/or exchange of diagnostic images between health care systems and health information networks? To what extent are these methods based on standards ( e.g., DICOM, DICOMwebTM, FHIR®, IHE® XDS-I, IHE® XCA-I) versus proprietary or custom integrations?
XDS-I.b is readily supported by 7 out of 8 vendors listed in Definitive Healthcare's "Top 13 PACS by Number of Installs" report. I determined this by downloading data from the IHE Connectathon Global Results page selecting the Cross Enterprise Document Sharing for Imaging (XDS-I.b) profile and comparing the listed companies against the companies listed in the Definitive Healthcare Report. There are 126 companies that have demonstrated support for XDS-I at IHE Connectathons.
XCA-I is readily supported by 5 out of 8 vendors listed in that report. XCA-I is simply the cross-community version of XDS-I and requires modest technical changes for implementation over the XDS-I implementation. I implemented a simple Web Viewer imaging application in 2010 using widely available open-source software while at RSNA on a system that already supported XDS and XCA in about 3 days, as I mentioned in "The Right Tools". It is a very modest lift from the existing XDS/XCA based national networking protocols.
SC-2. What metadata and other information is currently associated with diagnostic images for purposes of access and exchange, including images exchanged using different standards and custom integrations? Please feel free to elaborate on the use of artificial intelligence tools in adding metadata to images and additional information to accompany an image.
Key metadata for imaging that needs standardization are the codes used to describe the imaging procedure. Arguably, SNOMED CT and CPT could be used here but also consider RADLEX for the imaging procedure. Other metadata (e.g., reason for procedure, diagnosis) would also be useful for searching for imaging results. The modality (X-RAY, CT, MRI, SPECT, Ultrasound) is another key piece of metadata.
SC-3. What technical barriers, such as proprietary interfaces or ambiguous standards, limit the access, exchange, and use of diagnostic images across health IT systems (including by patient-facing apps), and should existing technical standards be further modified (please identify the standard)?
Assuming conformance to XDS-I.b or XCA-I, the real technical barriers are related to custom DICOM data supported and used by imaging modalities and/or generated by imaging workstations. Even so, several reports indicate 80% success rate importing DICOM images from media or networks. The failures are most often attributable to failure to follow the DICOM standard.
SC-4. How do certified health IT and/or EHRs enable or facilitate access, exchange, and use of diagnostic images today? Specifically, do EHRs play an active role in diagnostic image exchange, or is the functionality primarily driven by imaging systems such as PACS and VNAs?
While I'm told that you can get access to imaging studies through MyChart, my own experience with my provider is that such access is not available to patients. I have had in the past similar experience with EHR and PHR systems from vendors who have shown the capability to enable imaging access (in other words, the product supposedly supports image links, but the provider doesn't enable it), but that experience is somewhat dated.
Most imaging exchange systems that I have had experience with rely on PACS or VNAs, which makes this another reason to keep imaging exchange a separate criterion (see below).
SC-5. Should ASTP/ONC update the Certification Program to support the access, exchange, and use of diagnostic images? For example, an image access requirement could be added to the existing VDT certification criterion or additional imaging data elements could be included in the United States Core Data for Interoperability (USCDI).
ASTP should update the certification program. Additional data elements supporting imaging specific metadata should be included in USCDI, including imaging procedure and modality (see RADLEX). LOINC and SNOMED CT should be the vocabular used for other imaging metadata.
I'm not certain whether it would be more appropriate to create a separate certification criterion to support imaging data exchange, or if it would be better to combine this with the existing VDT criterion. I think generally, the long-term goal is that VDT should support both documents and images. Creating a separate criterion for it reduced vendor and provider burden by allowing for certification to the separate imaging access criteria, which would make it possible for it to be phased in over a longer period of time.
Because imaging data exchange is more usually handled by PACS or VNA, it's likely better kept as a separate criterion.
SC-6. Should there be a focus on particular, individual diagnosis and treatment use cases (e.g., ocular imaging)? Are there specific requirements that need to be considered for use cases in other fields?
I do not think imaging should NOT focus on a singular use case, modality or specialty. Instead, it should focus on imaging studies in general, perhaps with a specific minimum set of common modalities, including X-RAY, CT, MRI and Ultrasound.
I've had my eye doctor routinely text or otherwise send me my retina images (which I store on my phone), and the quality of that JPEG image is more than sufficient for retinopathy investigations, so would completely rule out the most common ocular imaging use case.
SC-7. Could image management systems, such as PACS and VNAs, be certified to specific certification criteria that would improve interoperability between these systems and EHRs and make access to diagnostic images available to “outside” providers and patients (including patient-facing apps)? What standards and capabilities should these certification criteria include?
IHE XCA-I, and DICOM provide sufficient criteria to support reliable imaging exchange.
SC-8. Beyond or absent the certification of health IT to specific technical standards, what diagnostic image-related standards should ASTP/ONC adopt on behalf of HHS to improve interoperability and health IT alignment?
Strict DICOM compliance is critical to ensure images can be used by the receiving system.
SC-9. Are there unique privacy and security concerns related to the access, exchange, and use of diagnostic images that may not exist with other types of health information?
Anyone who's watched any TV show that stars a medical examiner likely understands that imaging data IS PHI. The particular shape, placement, or measurement of internal organ characteristics is often sufficient to identify an individual, beyond just basic dental X-rays. It is simply NOT possible to deidentify such data.
SC-10. Would further development and adoption of the SMART® Imaging Access draft specification help address the access, exchange, and use of diagnostic images, as well as any specific privacy and security concerns related to such access, exchange, and use?
SMART Imaging Access relies on DICOM WADO, which is a later specification than XCA-I, and may be a more viable long-term approach. RSNA strongly supports the use of WADO-RS, which also has better integration than FHIR. I'm somewhat out of the loop on imaging systems these days, so cannot adequately speak to the support for WADO-RS in the imaging space, but it definitely seems like the appropriate long-term approach.
As to whether it would be better to adopt XCA-sooner I due to the light adaption necessary in existing national network specifications or focus more on WADO-RS and FHIR with SMART depends on timing and industry readiness. The lack of "hype" about SMART Imaging Access leads me to believe that it and possibly WADO-RS are not really ready for adoption yet.
References:
Top 13 PACS by Number of Installs, Definitive Healthcare, 2024, https://www.definitivehc.com/resources/healthcare-insights/top-PACS-number-installs
IHE Connectathon Global Results, Integrating the Healthcare Enterprise, 2025, https://connectathon-results.ihe.net/custom-search/
Outside imaging in emergency department transfer patients: CD import reduces rates of subsequent imaging utilization, PubMed, https://pubmed.ncbi.nlm.nih.gov/21507903/
The Right Tools, Healthcare Standards, Keith W. Boone, 2010, https://motorcycleguy.blogspot.com/2008/12/right-tools-make-any-job-easy.html
Medical Imaging Exchange, Healthcare Standards, Keith W. Boone, 2012, https://motorcycleguy.blogspot.com/2012/01/medical-imaging-exchange.html
Sharing Images on CD, DVD & USB: Standards, Tools & IHE PDI, IRWF and BIR Profiles, RSNAN, David Clunie, 2010, https://www.dclunie.com/papers/rsna2010_pdi_clunie.pdf
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