Advertisement

Easy transfer of digital image data: Principle vs implementation

      It is one of the advantages listed in every introductory digital imaging lecture: easy transfer, and thus improved communication, of patient image data. But is it true? Sometimes it seems that it was easier to exchange images when film was used as the recording medium. A 2-film packet provided the ability to retain 1 image on site and mail the other to the appropriate party. Even more convenient and time saving was the compatibility of viewing the film with a light box. With film, there was no need to buy a separate optical scanner to connect to your computer so that you could retrieve image data from a CD because your computer did not come with a CD drive. Likewise, depending on your clinical setup and the vendor-specific software on the CD, you may not have been able to view the images directly due to compatibility issues. For example, let's say the CD contains image data from a vendor that does not allow easy extraction of compatible .dcm files for import into your onsite reading software. This situation means different things for different people depending on your IT infrastructure, but for me it means having to locate someone from the IT department to help install the software from the CD because only IT personnel have the appropriate administrative rights required to install applications on university computers. This naturally delays the process and occasionally leads to image reacquisition to avoid participating in the information technology obstacle course.
      When physical media are involved, the digital transfer of image data can be time consuming and quite often frustrating. But direct transfer of digital imaging data should be easy, right? Well, it can be. Nonetheless, time has proven that it is not always easy for patients to get access to their digital images. This process often requires considerable effort on their part and on the part of the office staff that is trying to request access to the images from referring offices. The patients are often unsuccessful, or the process takes too long, or, worse yet, the received product is a printed radiographic image sent as an image file. This last scenario is almost as useful as when the digital image is sent via fax. Unfortunately, the hassle caused by the lack of a standard, easily accessible, compatible transfer method often leads to patients having their radiographs acquired again.
      This unnecessary re-exposure to radiation affects both 2-dimensional and 3-dimensional imaging. It is not uncommon for a patient with complex dental needs to undergo a cone beam computed tomography (CBCT) scan at one dental practice only to receive multiple additional CBCT examinations at other practices rather than having the initial exam transferred between the offices. Of course, there are instances in which the transferred image does not contain the area of interest that is needed, is not of adequate diagnostic quality, or is not acquired at the appropriate resolution. In these situations, reacquisition is necessary. Even so, the images should be retrieved and evaluated to determine if they are adequate before re-exposing the patient to radiation. Similarly, quality images should be made available to the patients so they can transfer them to a different treatment location. Unfortunately, transferring digital imaging exams is not always straightforward. It can lead to frustration and, again, the tendency to re-expose images rather than transfer them electronically between offices. And so, maybe there is a need for an electronic transfer method that accounts for the variable experience of the end user, software compatibility issues, and, as always, security.
      Due to experiences in medicine similar to those described above, the National Institutes of Health charged the Radiological Society of North America (RSNA) with creating an image exchange transfer method that would address these issues.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      The charge was not only to eliminate CD exchanges but to allow for impromptu transfer of imaging studies between unrelated clinical sites that are not part of the same network or picture archiving and communication system (PACS). The aim was also to make this process truly accessible; specifically, available in an open network environment and including patients in the process.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      Subsequently, RSNA has been working on developing an image share network (ISN) for sharing medical images along with the accompanying radiology reports.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      ,
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      Transfer between out-of-network clinical practices without the use of physical media such as CDs can occur through a virtual private network or through cross-enterprise document sharing (XDS).
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      Because the latter method is more amenable to impromptu data transmission, RSNA has collaborated with LifeIMAGE Inc (Newton, MA, USA) to develop a cloud-based method of transferring image data from a server located on a clinical site to a personal health record system accessible to the patient or to another unrelated clinical site.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      ,
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      To improve interoperability, the Integrating Healthcare Enterprise (IHE) XDS standards are used.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      IHE XDS is a set of policies and specifications, basically integration profiles, for exchanging medical documents.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      XDS-I (where “I” stands for imaging) adds digital imaging and communications in medicine (DICOM)based transactions and can be used for exchange of imaging data.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      XDS allows for exchange of DICOM-formatted image data for importing into the receiving site's software, and it can be packaged with an embedded viewer, which is necessary in the case of image data transmission to the patient.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      The LifeIMAGE cloud-based transfer system is referred to as the clearing house and is HIPAA-compliant.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      The clearing house is based on the IHE XDS-I.b profile (I.b is the current version in use) and serves multiple roles that include document registry and repository, imaging document source, DICOM image manager, and Patient Identifier Cross Referencing manager.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      ,

      Oracle. PIX/PDQ Manager Overview. Available at: https://docsoraclecom/cd/E19182-01/821-0867/hcp_overview_c/indexhtml. 2010. Accessed 2022.

      All communications between the acquisition clinical site's server, the clearing house, and the patient or destination clinical site are made through secure sockets layer transmission.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      Once offsite, the data is encrypted using hash functions.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      An edge server application is supplied by RNSA and is required to join the ISN. This application is freely downloadable from github.com and provides a user interface to send the image data to the clearing house.

      RSoNA (RSNA). RSNA/Image-Sharing-Network-Edge-Server. Available at: https://githubcom/RSNA/Image-Sharing-Network-Edge-Server. 2022. Accessed 2022.

      The end server also encrypts the data to be sent, and it remains encrypted while residing on the clearing house.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      ,

      RSoNA (RSNA). RSNA/Image-Sharing-Network-Edge-Server. Available at: https://githubcom/RSNA/Image-Sharing-Network-Edge-Server. 2022. Accessed 2022.

      Once the data has been present on the clearing house for 30 days, it is deleted.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      Any radiology site with an HL7-compliant radiology information system and PACS can link to the RSNA ISN.

      RSoNA (RSNA). RSNA/Image-Sharing-Network-Edge-Server. Available at: https://githubcom/RSNA/Image-Sharing-Network-Edge-Server. 2022. Accessed 2022.

      The patient's demographic characteristics and other protected health information (PHI) only become accessible at the receiving site (the patient or the clinical destination site). PHI is not directly stored within the clearing house.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      A hash function is used to encrypt the data, and only the end user with the appropriate information or key is able to decode the hash and access the PHI. This process enables patient demographic characteristics to be kept with the image data in the case of transfer between clinical sites, allowing the radiologists at the destination site to import and read the imaging study in their own software.
      • Langer SG
      • Tellis W
      • Carr C
      • et al.
      The RSNA Image Sharing Network.
      Therefore, when the image data is transferred between clinical sites, it does not have to be packaged with software, so it circumvents the compatibility issues we encounter sometimes with CDs. In cases of image data transfer to patients, an embedded viewer is used so that the patients can view their imaging exams.
      • Zhang J
      • Zhang K
      • Yang Y
      • et al.
      Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
      This is no easy task. It requires participation from multiple groups including software vendors; radiographic equipment manufacturers; and the societies, groups, and committees responsible for developing standards. Some vendors market their product as a closed system, meaning the user is required to use both their equipment and software. On the other hand, there are vendors who market their products for compatibility and interoperability. It is this latter structure, along with image and data exchange standards, that will ultimately allow improved patient care through better image transfer.
      Dentistry has stepped into the territory of image transfer by using cloud-based transfer services and promoting the DICOM standard. But a universally accepted transfer system does not exist at this time. Instead, systems provided by different vendors are used. Because the process in dentistry is not being pushed by standards groups, there are multiple systems with different steps, and therefore different learning curves, involved. For example, there is a cloud-based transfer service system at our institution that is both HIPAA- and FERPA-compliant, but it is not designed for image transfer. Therefore, there is no end-user application like the edge server used by RSNA's ISN that encrypts the data and pushes it to the cloud-based server. Furthermore, there is no mechanism to bundle the data with an embedded viewer to send to the patient. There are settings that enable password protection and auto-deletion from the cloud-based transfer service's storage after a certain period, but users must set all these details each time they send image data. Users also must download the image data from the PACS system, with or without a viewer depending on the destination site, and then upload it to the cloud-based transfer service provider. Therefore, the system is a little less user-friendly and comes with variable learning curves. Unfortunately, all these things threaten to incentivize clinicians to reacquire images rather than obtain them electronically.
      From the perspectives of radiation safety and diagnosis, the ability to transfer imaging data among multiple treatment sites is not only beneficial but a necessity that patients and clinicians deserve. How many times just in the past month have you recommended that your findings from an imaging exam be compared with previous imaging studies? I know it would make my life easier to have access to older images for comparison with current radiographic findings. This ability would enable a more definitive radiographic diagnosis in many cases and avoid the necessity of resorting to the adage “initial, periodic follow-up is needed to confirm the radiographic impression.” And so, although dentistry has come a long way and has improved the digital transfer of imaging exams, there is still quite a lot of work to do. Perhaps there is room in dentistry for a universal standard method of transferring patient imaging data. Maybe dentistry should follow the lead of RSNA's ISN. Though time will tell, it seems quite possible that, with time, dentistry will develop a more user-friendly ISN to better serve the imaging needs of patients and clinicians.

      Disclosures

      None.

      Funding

      No financial support was received from any external source or vendor for this project.

      References

        • Langer SG
        • Tellis W
        • Carr C
        • et al.
        The RSNA Image Sharing Network.
        J Digit Imaging. 2015; 28: 53-61
        • Zhang J
        • Zhang K
        • Yang Y
        • et al.
        Implementation methods of medical image sharing for collaborative health care based on IHE XDS-I profile.
        J Med Imaging (Bellingham). 2015; 2046501
      1. Oracle. PIX/PDQ Manager Overview. Available at: https://docsoraclecom/cd/E19182-01/821-0867/hcp_overview_c/indexhtml. 2010. Accessed 2022.

      2. RSoNA (RSNA). RSNA/Image-Sharing-Network-Edge-Server. Available at: https://githubcom/RSNA/Image-Sharing-Network-Edge-Server. 2022. Accessed 2022.