DICOM Routers a Thing of the Past?

DICOM is an acronym for:  Digital Imaging and Communications in Medicine.  It is a standard for handling, storing, printing, and transmitting information in medical imaging.  The current version of the standard is 3.0.  I have been dealing with DICOM for the past twenty-five years.  The key to DICOM (or any other standard) is to make products from different vendors to be able to interconnect.  Before DICOM larger companies had a monopoly on systems.  Once a company got a foothold at a healthcare facility it was almost impossible to switch or get better equipment for specific captures.  For example, some companies specialize in ultrasound while others in MRI.  Before DICOM, healthcare facilities had to choose a vendor and run with it or have redundancies to accommodate the different vendors, which was and still is quite expensive.

The problems with DICOM are quite obvious and there are reasons why.  DICOM is cumbersome, inefficient and poorly specified.  The reason is that is was designed by committee whose members were not computer scientists and electrical engineers.  Representatives came from different vendors that wanted to impose their ideas and protocols in order to get faster and deeper market penetration.  One way or another the benefits that DICOM brought to the industry are obvious and welcomed by healthcare providers, not so much by vendors who still try to eliminate competition by stating that if other DICOM products are not certified with their implementations they will not be able to provide service or might even void warranties.  It is interesting that in all the years I have been dealing with DICOM I have run into a situation where a vendor would put such opposition in writing.

With the advent of globalization, specialization and costs (recent changes in healthcare reform have increased) medical images (e.g., CT, MRI, US) might be captured in an imaging center.  DICOM images need to be sent to a radiologist specializing in the type of modality (e.g., CT, MRI, US).  The radiologist generates a report that must be associated with the images and sent to the referring physician that ordered the study.  If time is not crucial to the outcome, then the DICOM data could be transferred using optical (i.e., CD, DVD) or other removable media (i.e., USB disk, USB memory).  In most cases transfer speeds are important and they are done over open (e.g., Internet) or virtual private networks (VPN).

To add to this, there are some regulations, courtesy of HIPAA (Health Insurance Portability and Accountability Act), that specify, among other things, who is responsible to store the DICOM data, for how long should the DICOM data be stored and who has access to such DICOM data.

There are other issues that fall in the realm of overall system design.  Most of these escape the design and implementation of most products just because of scope and reduced engineering resources available to most companies.  This is especially true now a day when most design and implementation activities are done abroad (i.e., China, India) by companies that bid the lowest on a project.  As an example of some of the missed requirements / qualities are consistency, redundancy and availability.  What if different copies of the same DICOM object are different?  The differences may be valid due to changes made on the object following standard procedures or they may be maliciously performed to hide some evidence that could require an insurance company to pay a considerable settlement in a malpractice lawsuit.  It becomes difficult to manage multiple copies of a DICOM object when they are in disparate media types, on different private systems or in some type of removable media forgotten in a drawer or in a closet in a private or public place.  When multiple copies of a DICOM object are floating around how can they be located when needed if they are in private systems at healthcare providers, referring physicians, or in removable media.

I have been designing and implementing computer based systems for disparate vertical markets for a rather long period of time.  I very well understand that thinking out of the box is quite rare.  Most junior engineers tend to believe that something they learned while attending school or read in the last issue of a technical publication could be blindly applied to improve on something that needs it (i.e., DICOM).  I recall an electrical engineer that had designed a computer bus that was faster that what was available at the time.  For a few years all he would consider was changing from EISA or VME to his creation.  The problems with using non-standard hardware or software are not just a unique feature but compatibility, overall performance, additional modules, and support just to mention a few.

Based on all what has been said so far, perhaps the time and technology is ripe for a next generation of DICOM routers.  The idea would be to come up with a design what is easy to use, does not break existing systems and follows the DICOM standard.

A typical set of DICOM routers would be used as follows:

1] DICOM images for a patient are captured by a modality (e.g., CT, MRI, US) and sent using the DICOM protocol to a DICOM router.

2] The DICOM router would have a set of rules to send a copy of the DICOM objects to local storage in a DICOM archive and another copy to a remote location to be read.

3] A DICOM router receives the DICOM objects and routes then to a local storage and to a viewing station.

4] A radiologist, specializing on the type of image, would read the set of DICOM images and generate a report.  The report would be typed in or transcribed and sent to the DICOM router.

5] The report and images would be sent to a DICOM router to be sent to the referring physician clinic.  A copy of the report would join the local copy of the DICOM images in case there are questions or they need to be resent to the destination or to a new destination at a later time.

6] The DICOM router at the final destination receives the DICOM objects and sends a copy to the local storage and a copy to a viewing station.

7] The DICOM objects, which include the images and report, await the referring physician.  Based on the report the referring physician decides on a course of action for the patient.

The typical system has several isolated private copies of the same DICOM objects.  The system as a whole makes use of several DICOM routers, each with its own set of rules, each controlled by different organizations.

A new DICOM router could be designed and implemented as illustrated in the following figure: 

1]  DICOM images for a patient are captured by a modality (e.g., CT, MRI, US) and sent using the DICOM protocol to a Content Addressable Storage (CAS) with a DICOM front end implementing a DICOM archive.  The archive uses the DICOM protocol to receive the DICOM objects.  It makes multiple copies in different locations and on different types of media.  The number of copies, their location and media type are configurable.

2] The DICOM front-end interface at the offshore reading center determines that the CAS has received DICOM objects specifying it as a destination.  The DICOM front end at that remote location transfers the DICOM objects to a DICOM viewing station for them to be read by a radiologist.

3]  When done with the read, a report is transcribed (if needed) and sent to the CAS.  Please note that the DICOM images do not need to be sent back unless they have been altered.

4] There are at least two ways the DICOM images and report can get to the final destination, which is the referring physician at a clinic.  In the first approach, after the CAS receives the report, the report and DICOM images are sent to the viewing workstation.  On a different approach, the DICOM objects are sent to both the offshore reading center and to the viewing station at the referring physician clinic.  Later when the report is completed and stored in the CAS, it is sent to the viewing workstation via the DICOM protocol.

As a system, the second implementation is quite more elegant, probably less expensive and quite more reliable than the first approach.

I welcome comments and suggestion regarding this blog entry.

The Naïve American

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