PACS helps move pathology toward enterprise integration

As informatics penetrates deeper into other medical specialties, so do the issues of standardization and integration surrounding PACS and digital imaging.

In pathology, for instance, the technology of whole slide images (WSI) has matured to the point that many vendors now offer solutions to produce these kinds of digital images, necessitating the development of standards.

Integration of WSI into PACS is clearly desirable. Pathologists consider WSI of much more diagnostic value than still images. A specific DICOM working group (WG26) was recently formed to achieve PACS/WSI integration.

A recent paper (Stud Health Technol Inform 2006;124:371-376) describes ongoing standardization efforts from the Integrating the Healthcare Enterprise, HL7, and DICOM in the field of pathology for defining a standard model of specimen (parts, blocks, and slides).

"Quality assessment studies in anatomic pathology show that each of the different steps from specimen processing to report editing may be the source of errors," said Dr. Christel Daniel-Le Bozec of L'Université Paris Descartes. "It is therefore important that information systems in pathology departments rely on a well-defined and shared standard specimen model."

Currently, information acquisition can be time-consuming, since pathology information systems are not integrated. Data must often be entered more than once, compounding opportunity for error. Orders, images, and reports are spread over different systems that do not communicate.

Daniel-Le Bozec's paper presents a methodology to integrate the anatomic department with the enterprise.

"Although standardization efforts conducted by HL7 and DICOM are progressing to provide integration solutions, HL7 or DICOM messages contain many optional data fields, so that being DICOM- or HL7-compliant does not necessarily imply integration," she said.

The principal contributions of this work were to analyze the specificity of anatomic pathology workflow with regards to radiology workflow, according to Daniel-Le Bozec. The diagnostic process in pathology differs from that in radiology since it is specimen-driven.

"When digital imaging is performed, many types of equipment - gross imaging, microscopic still imaging, WSI, multispectral imaging - may be involved for a single examination," she said.

In radiology, the diagnostic process is patient-driven. An examination usually involves a single image acquisition modality.

Another goal of the paper was to define the structure and content of cases, orders, image folders, and reports.

One issue was to define the links between information entities (order, image folder, report) and real-world objects (specimen, tissue samples, and slides), she said.

The paper documents the successful definition of XML schemas for case representation, based on DICOM Visible Light and DICOM Structured Reporting objects, and the development of a DICOM module to export DICOM image files and reports stored in PACS.