French Society of Radiology: Automated selection of archived images cuts costs
The guidance clearly distinguishes between storage of modifiable image data for current and recent clinical cases and subsequent non-modifiable archive material – also recommending separate systems for data handling, as well as automatic storage and archiving protocols to optimize the processes, minimizing labor and lowering archiving costs.
“Hospitals in France produce many terabytes of data per year. This is a lot of archiving space and a huge financial burden. Our goal was to decrease this,” said Dr Daniel Reizine, Neuroradiologist at Lariboisière Hospital (University Hospital Paris 7), PACS coordinator for Paris Public Hospitals, and member of the SFR informatics working group charged with creating the good practice recommendations.
The guidance is for use in the selection and conservation of digital medical images, the objective being to store and archive information pertinent to the diagnosis and follow-up of patients in line with legal requirements. For all French hospitals, whether private or public, medical files must be archived for 20 years from the date of the patient’s last consultation in the establishment or until the patient turns 28 if the legal duration terminates before then. If the patient dies within ten years of the last visit to the hospital the file is to be kept for ten years from time of death. Any time limits are suspended for legal cases taken against the establishment or staff practice.
Legally, ‘storing’ can be defined as any action, tool, or method that captures electronic data and that allows later treatment of these contents. The stored data are not ‘fixed’, and can be modified, deleted, or replaced, which means the duration of storing is not defined by law.
Archiving, by contrast, includes any action, tool, or method that captures, identifies, selects, classes, and preserves electronic data securely so that falsification is not possible, guaranteeing the integrity of the information for either informing or for serving as evidence in legal cases. Although accessible, the data are fixed and cannot be modified, therefore archiving is subject to a legal framework that includes the length of time data must be preserved.
For efficiency purposes, SFR recommends automatic storage protocols should be in place at the time of production, adapted to modality and clinical indication. A CT scan can generate around 20,000 images but not all of these should be sent to the picture archiving and communications system (PACS). Such automatic selection would save radiologists time and eventually reduce the number of images to be archived.
In addition, storage systems should provide the option of a reversible compression (without loss) in line with digital imaging and communication in medicine (DICOM) Lossless specification. Authorized users such as clinicians or radiologists should benefit from immediate access to all exams in the storage system, which might be standalone or shared between different centers for primary or secondary interpretation. Medical image archiving systems can also be standalone or shared between establishments, and may house several types of data, according to the SFR.
“Archives should be independent from PACS so that if you change the PACS system you don’t need to systematically change the archiving system,” Reizine said. “Imaging data transferred to the archives should only be a portion of the entire production, this automatically selected through adequate archiving protocols.”