By Shaun Smale, Solutions Architect, BridgeHead Software

Ask yourself these questions: what cost would you put on short and long term data loss or unavailability (i.e. from planned outages and unplanned disasters) within radiology, both in economic terms and in relation to the level of patient care? What would be the impact on patients if, for example, four-year-old medical images were lost or not instantly available? In most cases, I suspect the answer will be ‘not significant’, but with the caveat that ‘for chronic conditions that require regular check-ups’, loss of data or lack of data availability could be critical’.

In the days before the digitisation of images, film was frequently unavailable when clinicians needed it – either misplaced in and around the hospital, left in the clinician’s car, or misfiled in the library. Fortunately, the report could be more readily found in the patient’s notes or in Radiology Information System (RIS). Unavailability of film is the equivalent of loss of data. At the time, this data loss was deemed almost acceptable. So why is it that data loss is now considered such a serious issue? What has changed? The answer may lie in the fact that, post-digitisation all data is expected to be instantly available and so the easy option is to store everything.

Just to be clear, I am not suggesting that data loss is acceptable, quite the contrary – I am a firm advocate that all patient data should be treated with the utmost sensitivity and proper measures should be put in place to protect it. But how much would you pay for ‘zero data loss’ and how does this relate to both NHS guidelines on data retention or that of private hospitals? To me, this is very interesting as there is a fine line between the clinical and financial argument.

Having secured your data, what financial value would you place on having immediate access to all priors? If you ask a clinician today about what data they want and how quickly they need it, I suspect the answer would be ‘I need to have all priors on my workstation at the start of the consultation’. Let’s explore what that means for the archive in which your images are managed?

Take the following scenario: patient clinics are not scheduled via the Radiology Information System (RIS) and so a means to trigger a quick retrieval of off-line studies from the archive is required. Once you start discussing the financial implications of storing everything on expensive fast access media, then PACS managers themselves begin to ask how they balance the cost of that access to relevant priors against the probability of them being in the PACS short-term cache. This is where intelligent pre-fetch or auto-routing, and effective storage management, can balance the cost of storage against the probability of review after the initial episode has been concluded.

Recent healthcare storage studies show that once data is purged from a PACS cache only a very small percentage of the total volume archived is viewed again (estimated at around 2%). Therefore, where is the logic in storing data that is unlikely to be accessed again on super quick, and often expensive, fast spinning and high availability disk storage?  Surely there is a better way? (You can read more on correctly archiving data to ensure image retrieval in a recent blog from us here).

So, ask yourself a related question – if we have policies to cull data, do we believe ‘zero data loss’ is a critical requirement? As far as I am concerned, the answer is ‘yes’, but not at a premium cost. To ensure that a relevant prior study is available at an annual consultation, should all data be on-line or instantly accessible from the archive by investing in vast arrays of high performance storage? Or, alternatively, should we apply complex algorithms to endeavour to deliver the relevant study in advance to the viewing workstation? If one of your goals is to maximise efficiency and minimise storage costs without impact to patient care, then surely the latter suggestion has more appeal?

Finally, in the days of film, physical space was a premium in terms of both cost and accessibility. Armies of clinical staff routinely purged and destroyed film to save room. In this digital age, would you sign the dotted line granting the deletion of an electronic study? At what point would the financial argument for storage space and accessibility justify the destruction of electronic studies, performed not by armies making clinical decisions, but by programmers and algorithms?