Migration to native SNOMED CT electronic patient records is in progress in the United Kingdom National Health Service (NHS). In order to promote interoperability, usability and activity reporting, the NHS introduced a national standard set of imaging codes in 2005 – the National Clinical Imaging Procedure code set (NCIP).
While SNOMED CT was the prime candidate for populating the NCIP, many Radiology Information Systems (RIS) and Picture Archiving and Communication (PAC) systems at the time could not accommodate SNOMED CT 18-digit concept identifiers or (up to) 255 character descriptions without disruptive and costly software changes. There was also no consistent way to represent laterality of procedures, and some legacy systems required the creation of separate orderable items for each laterality – for example 'Plain X-ray left wrist', 'Plain X-ray right wrist', and 'Plan X-ray both wrists'. For these reasons, the NCIP code set was developed based on SNOMED CT, but with the addition of unique identifiers compatible with legacy system's character limitations (6 alphabetic characters), up to 40 character human readable descriptions, and additional laterality metadata. For example, 60027007 | Radiography of wrist| is represented within NCIP as:
Right and left
XR Wrist Both
XR Wrist Lt
XR Wrist Rt
NCIP short codes are 'meaningful', in that the modality of the procedure is defined by the first character of the code, and the finding site and laterality are both explicitly represented in the code.
Each hospital submits mandatory data extracts using NCIP from both legacy and SNOMED CT capable RIS. In addition to details of the imaging procedures, information about the referral source, patient type, demographics and times of each imaging related event are also collected centrally. The data from all sites is then combined and multiple reports are extracted. Hospitals can view their activity data via the iView web based reporting tool (see Figure 12.1.5-1) and compare their activity with other centers.
Analytics on this central platform are wholly SNOMED CT based. SNOMED CT hierarchies support sophisticated reports – for example, the monthly waiting times for Magnetic Resonance Imaging excluding Cardiac MRI and MRI guided procedures is specified as:
Includes hierarchy << 113091000 | Magnetic resonance imaging|
Excludes hierarchy << 258177008 | Magnetic resonance imaging guidance|
Excludes hierarchy << 241620005 | Magnetic resonance imaging of heart|
Figure 12.1.5-1: Detail of SNOMED CT based report on the NHS iView platform