PACS Migration Service – pdfNIPACS Case Study

MDI has comprehensive knowledge and experience on a wide variety of PACS Systems.

Often PACS vendors can move their own data from one system to a new generation of their solutions. However, changing vendors is often a daunting task which exposes both the owner of a legacy PACS and the new vendor to uncomfortable risks in assuring data quality and solving unanticipated problems as they are encountered in any PACS Data Migration project.

A PACS Migration needs to address a variety of complicating factors and the process needs to be managed effectively.

For example, some considerations are as follows:

  • The growth in the use of CT produces many images.  Each represents a slice of the body.  Care and attention to detail are required to move each of these studies in a complete manner.
  • Patient identification is complex. There are a variety of techniques to register and identify a patient for their hospital visit; hospital work flow considerations such as patient verification and how this is carried out at a particular modality, or by means of a RIS work list. There are unintended fail points that trigger errors in how captured images are associated with patient details required by other information systems.
  • Each PACS system has its own routine to verify a study, i.e., accept it into its database.
  • Older source PACS hardware is prone to failure. Care must be taken even with how often any given disk in a source PACS’ archive can be read.
  • A migration often brings a study into a PACS’ cache prior to moving it, so a balance must be struck if the legacy PACS is still required to be available.
  • Demand on network infrastructure varies throughout the day, so study retrieval coordination must be done with consideration given to time of day and volume.

Migration projects that are well planned can take a few weeks to several months. Those that are several months in duration often benefit from an ability to prioritize migrations with scheduling systems, to get prior studies moved to support the radiologist seeking prior studies for comparison. This involves listening to the RIS systems through HL7 messaging to prioritize the move of prior studies, to service a currently scheduled patient.

MDI has the expertise to assist Radiology and Diagnostic Imaging centers to seamlessly transition to a new PACS system by providing cost-effective, real-time access to legacy images. MDI has successfully migrated data from a variety of DICOM compliant systems including:

  • GE
  • Siemens
  • AGFA
  • Fujitsu
  • Cerner

The following themes and questions should be reviewed when considering a PACS migration:
Merger of two or more archives
There are business and technical drivers behind merging an archive. A hospital could have acquired a clinic. A migration often follows as part of an effort to reduce overall costs and standardizing on one PACS vendor. Also, information systems and clinical workflow considerations can drive an archive merger. For example, it may be that Mammography and Cardiology studies need to be consolidated with studies from other sources.
XDS-I to enable referencing foreign studies and documents as an alternative to migration
XDS-I is gaining acceptance as a technique to enable a PACS to make its studies available to another XDS-I enabled PACS. This may be an alternative to a complete PACS Migration – often there is a need to share studies and build a common repository.
Mismatched patient/study information
It is possible to clean up mismatched data and it is possible to automate most of the clean up, for example, make modifications to study identification in the DICOM header and maintain the original identifiers.
Value from studies that do not pass RIS verifications tests
It is often a good idea to consider an unverified store that can be queried by external applications. There are sometime minor issues that make a study unverifiable, for example, date of birth or family name errors that are input at the modality. The study can still make a considerable difference to a radiologist seeking prior studies from a variety of sources.
Archive vendor proprietary issues
It is not unusual for vendors to charge handsomely for a study list and an estimated volume of studies in the current PACS. Migrating just a few studies with a variety of dates, study-types and media sources provides indications of the migration effort. It is also not unusual for a PACS vendor to underestimate the migration effort. This can create a difficult scenario to carry out the migration when the migration effort is tied to acquisition of a new PACS, because it may not meet committed time frames.
Vendor proprietary tags & annotations
It is often a surprise that many annotations and tags used on studies are not DICOM compliant. It is difficult to retain the tags and annotations in a migration because the migration uses DICOM standards to move the studies. Setting expectations in this regard is key to addressing this issue.
Maintaining LIVE PACS availability levels
Regional PACS implementations often have specific service levels of availability and the DICOM study migration adds a risk factor. Scheduling the migration for after core hours when network loads and archive activity is minimal is the best technique. However, it is possible to perform the migration during core hours at a slower pace that will not interfere with daily operations.
Estimating the migration duration
This is difficult to be certain until the migration is in process and requires non-traditional planning considerations. The duration is as much a function of identifiable controls over the network and target archive capabilities as unidentifiable obstacles such as environmental activities that affect the data centre.
Options to reduce migration cost
The adage “time is money” certainly applies to DICOM study migrations. It is often a detailed background activity that escapes the attention of tangible undertakings. It is best to identify directly interested parties and indirectly interested parties that have a stake in the migration process whether they know it or not. In sum, anything that can reduce or eliminate migration disruptions presents a quantifiable opportunity to reduce costs.

PACS Migration planning tips:

  • What are the sources of PACS data: e.g. – archive(s), directory of image files, off‐line media and cache?
  • How many source locations are there?
  • How many exams do you need to move?
  • What is the estimated volume of data that you need to move in Terabytes? (Please note that applying archive compression in a uniform manner doesn’t account for variations in compression.)
  • Does the destination PACS already contain any exams that are also on the source? (For example, this could happen after the destination PACS has gone live and it has queried the source PACS for the study and moves it as part of a pre-fetch activity.)
  • Do you need to change any of the data?
  • Do you need the migrated data to be verified by a RIS or other checks?
  • Do you need to fetch prior studies during the migration? (May be required if you have a large migration project that is likely to take more than 6 months to complete.)
  • Where are the upcoming patients or exams defined? (e.g. ‐ modality work list server)
  • Do you have a particular schedule that dictates when and how fast you can migrate studies? (Consider network bandwidth.  Also, it is often faster to pull studies from a source PACS rather than have them moved to a target destination and have the study verified on the RIS)
  • Do you need to run slower during the daytime working hours?
  • Are the source and destination archives fully DICOM compatible?
  • Can Query Retrieves be issued to the source PACS and the destination PACS and do they each have a DICOM Q/R interface?
  • Are there any proprietary tags, annotations or mark ups? (Please note, often these are not DICOM compliant and are not transferable to the destination PACS)

Free Site Survey & Cost Analysis

At no cost to your facility, MDI will provide prospective migration sites with a Site Survey template, which details the current and future PACS environment.  Based on the Site Survey information, MDI will provide a written assessment, including costs, that details the tasks required to migrate your legacy PACS. Please contact to arrange the Site Survey.