An introduction to DICOM

To send digital images from one workstation to another, they must speak the same language—and that language should be DICOM.

Digital Imaging Communications in Medicine (DICOM), a set of comprehensive communication standards, was developed to promote interoperability of digital imaging devices in human medicine.1-3 Before DICOM, digital image formats in human medicine were not standardized, and digital images created on one manufacturer's equipment could not be viewed on a competing manufacturer's workstation. This lack of standardization not only hampered the exchange of information among physicians but also exerted undue pressure on hospitals to purchase equipment from the same manufacturer.3 The American College of Radiology and the National Electrical Manufacturers Association recognized the need to develop imaging and data standards and addressed it by jointly developing DICOM,4 which is now the accepted imaging standard in human medicine.


Jonathan T. Shiroma, DVM, MS, DACVR
Although digital imaging is relatively new to veterinary medicine, it is becoming increasingly important that the profession standardize its digital format so we do not suffer the same difficulties human medicine faced. Consequently, the American College of Veterinary Radiology (ACVR) supports the use of DICOM as the digital imaging standard for veterinary medicine and sponsors a committee (DICOM workgroup 25) to incorporate veterinary terminology and nomenclature into the DICOM standard.

DICOM BASICS

Making up the most basic level of dicom, which is also the most relevant to veterinary medicine, are standards for image exchange between senders and receivers. Several different types of images (e.g. JPEG, RLE, JPEG-LS, JPEG 200) can be used in DICOM files.4 While DICOM is commonly referred to as a type of image, it is not—it's an image format. DICOM files consist of image pixel data and precise attributes (identification, management, and acquisition information) combined with services (e.g. commands for transmitting data), resulting in service-object pair (SOP) classes. SOP classes represent the basic unit of DICOM conformance: Devices can be a service class user, which sends images, or a service class provider, which receives images and stores them for the user.1,2,5

Implementing digital imaging typically involves adopting some format for archiving images and for distributing images (and associated data) to workstations and, possibly, outside the hospital (e.g. to other veterinarians or veterinary radiologists). DICOM is the tool that permits standardized communication among various devices (e.g. acquisition device, archive device, display device).3