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Using Automated DICOM Prefetch for Legacy Applications with UltraPREFETCH

In the dynamic landscape of healthcare technology, the growth of Picture Archive and Communication Systems (PACS) has been remarkable. This growth has led to the need for innovative solutions to enhance the functionality and efficiency of PACS, particularly in radiology. In this blog post, we delve into the revolutionary UltraPREFETCH solution, focusing on its automated DICOM prefetch capabilities and its impact on radiology workflows.

Using automated DICOM prefetch capabilities and leveraging its impact on radiology workflows.

Understanding the Evolution of PACS

Over the past decade, PACS has undergone significant expansion, moving beyond its radiology-centric origins. This expansion can take two primary forms: the addition of specialized workstations and incremental reading sites (near-line workstations) or the replacement of PACS architecture, transforming online and integrated archives into near-line PACS devices. This shift to near-line devices, while integrated using the DICOM standard, presents challenges in fully integrating with modern PACS due to differing architectures.

Prefetch Triggering Mechanisms

Triggering Logic

  • Relevant prior patient information is crucial for accurate diagnoses, prompting the need for prefetching. Prefetch rules define when prior studies are relevant to the ongoing study, requiring defined logic. Whether triggered by HL7 messages or DICOM header information, the prefetch process hinges on precise rules to ensure optimal workflow.

HL7 Triggering

  • HL7, a standard for medical information system communication, plays a pivotal role in triggering prefetch events. Admission/Discharge/Transfer (ADT) and Request for Observation (ORM) messages provide patient and procedure details, aiding prefetch workflows. While both ADT and ORM messages offer patient information, ORM messages uniquely include ordered procedure data, enabling more precise prefetching.

DICOM Triggering

  • DICOM, the standard for storing and transferring medical images, complements HL7 in triggering prefetch events. The DICOM header information facilitates logic similar to HL7 messages, although extracting information from DICOM implies the event has already occurred, potentially leading to delays.

Triggering a Prefetch Event 

  • Both HL7 and DICOM-derived information is typically stored in a SQL database in a standard format. Periodic parsing of the database triggers prefetch events based on predefined criteria, allowing for efficient and timely data movement.

Finding Prior Studies

  • Prefetch systems utilize C-FIND DICOM messages to query associated DICOM devices for prior studies. The comprehensive list of prior studies allows prefetch to identify and transfer relevant data based on study type and logic.

Moving DICOM Data

  • The actual transfer of DICOM data matching the defined logic is accomplished using C-MOVE DICOM messages. This process automates data movement, optimizing workflow efficiency.

Near-line Archive Use Case

Retiring an Archive: 

  • As PACS archives near retirement, accessing and migrating data efficiently becomes imperative. There are challenges of retiring archives, but there are also benefits of prefetch in the context of transitioning from client/server to peer-to-peer PACS architectures.

Client/Server vs. Peer-to-peer PACS: 

  • The transition from client/server to peer-to-peer PACS architectures is examined, emphasizing the complexities of accessing data from old PACS when migrating to new PACS environments. Prefetch emerges as a viable alternative to costly and time-consuming data migration.

Prefetch vs. Migration: 

  • Comparing the options of migrating entire datasets versus pushing relevant prior data on demand, we argue in favor of prefetch as a cost-effective and efficient solution. Real-world examples underscore the potential savings in time and effort achieved through prefetch workflows.

Near-line Workstation Use Case

Dedicated and Specialized Workstations:

  • Certain DICOM data requires specialized workstations for accurate interpretation. There are challenges of integrating these workstations with client/server PACS environments and there are plenty of benefits of prefetch automation streamlining the process.

Automating Data Movement:

  • Prefetch automation proves invaluable in efficiently moving data to dedicated workstations. There are time and resource savings achieved through automated prefetch processes, particularly in scenarios where manual intervention is prone to errors.

Atypical Prefetch Application:

  • There is an unconventional use case of prefetch in a regionalized healthcare environment with limited bandwidth. In this scenario, prefetch automation, driven by HL7 and DICOM data feeds, enhances efficiency by offloading data transfers to off-peak hours.


Summarizing the benefits of prefetch usage, we categorize its applications into three key use cases: near-line archive to online archive, online to near-line workstation, and atypical applications in regionalized PACS environments. Triggering prefetch through HL7 and DICOM data feeds is discussed above, with a preference for HL7 due to its ability to drive prefetch based on data from radiology information systems. Check out our UltraPREFETCH solution to see how we can help you!


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