Picture Archiving Communication Systems, commonly termed PACS are a combination of systems including servers, software, and networks. The images are usually stored on an image server which the software application accesses when clinical personnel click to view an exam or patient record. The servers in the PACS architecture are linked by the hospital's network, commonly called the LAN or Local Area Network.

The Hospital Info System or commonly called the HIS is the main hospital software system which maintains the full patient record. Radiology exams are usually ordered through the HIS or some ancillary order-entry system and then routed to the PACS system via interface or direct integration. Generally, if it is a new patient, the HIS creates the new database record which would include information such as: MRN, account and/or visit number, and the unique radiology exam id or accession number. When the radiologist reads the exam, the result is created and added to the patient record in the HIS. Sometimes the HIS receives this result directly through a voice recognition system or from a transcription system.

The modality receives the exam order from the HIS via an interfaced worklist or sometimes directly from the PACS. The different clinical software systems send exam information using various standardized programming languages( e.g. HL7 2.x or xml) via the hospital LAN(Local Area Network). As the modality generates the images they are sent to the PACS server(s) via the LAN. The PACS application receives the images in standardized DICOM(includes information about the patient) format and usually stores the images in a special image archive storage system(usually a Storage Area Network-SAN).

The imaging technologist uses a workstation connected to the hospital network or the web to process and view the PACS images using the hospital's standard quality control procedures. All annotations, documents, and notes are passed to the patient's database record via the PACS user interface.

DICOM images are accessed through the workstation by requesting to view an exam to the PACS server.

Dicom Structured Report(SR) files are special DICOM files generated in the ultrasound machine containing measurement and other procedural data with the images. Some ultrasound vendors may have DICOM-SR capability. DICOM-SR can aid in report efficiency and accuracy and automatically pass measured data to PACS and transcription systems. DICOM-SR can also improve tech workflow by eliminating manual measurement documentation.

The Radiologist views the patient exam using a workstation that resides on the hospital network or via the web. The PACS software application provides a user interface for the radiologist to request images, documents, and exam information. Commonly, the radiologist dictates into a transcription or voice recognition system which sends the information over the network to the PACS and/or the HIS.

Teleradiology is a method for giving image and patient exam access to radiologists who work outside the imaging department. Teleradiology systems are often directly integrated into the PACS system or an added module. The radiologist can access patient images stored in the PACS system via a worklist either through a secured web connection or a Virtual Private Tunnel(VPN) into the hospital network. Teleradiology can improve patient care in many ways, including better access to radiologists who specialize in certain areas. Additionally, teleradiology firms can offer 24/7 services to improve report turnaround time and off-hours services.