Canada's Strategies for Lossy Compression in Medical Imaging

1. What is Canada doing about Lossy Compression? Peter R.G. Bak, Ph.D. Project Director, Diagnostic Imaging and Laboratory Architecture Canada Health Infoway 15 February, 2006

2. Disclosures • Peter R.G. Bak is a consultant working for Canada Health Infoway

3. Lossy Compression in Canada • Canadian Association of Radiologists (CAR) have endorsed the use of lossy compression “in principle” • CAR intends to fully endorse lossy compression as a standard of practice by end of 2006 • Confirm that lossy compression does not impact visual quality through clinical evaluation • Develop practice/ratio guidelines to assist radiologists/health authorities with implementation

4. Context: The Motivation for Compression • Canada has initiated the deployment of a pan-Canadian interoperable Electronic Health Record solution (EHRs) • Canada Health Infoway (Infoway) is an independent, not for profit corporation responsible for developing the architecture of the EHRs • A core component of a patient’s health record is the diagnostic imaging result: medical images, radiology reports and evidence documents • Canada is moving aggressively towards a fully filmless medical imaging environment – we want to print less than 2% of our exams

5. Context: The Motivation for Compression • Canada performs about 35,000,000 exams annually • This equates to about 3.5PB of storage annually • We have an aging population – expect an increase in exam volume and CT utilization • Canadian healthcare facilities are widely dispersed across a large geography • Over 540 facilities (<100 beds) in rural Canada • Network connectivity is limited – most rural areas have 1mbps connectivity • Canadian Radiologists and Specialists are centered in the larger metropolitan cities • The challenge is getting images from rural facilities to metropolitan centres in a timely manner

6. Context: The Motivation for Compression • Storage Costs • Storage costs are coming down but the storage volume is going up • We expect consumption increase will offset price decrease • Storage costs are significant (~$50M)… but not significant enough to drive change! • Storage “Total Cost of Ownership” is far more significant…enough to drive change! • Infoway is completing an economic assessment that indicates significant cost savings…yet to be completed and published! • Network Costs • Increasing bandwidth to rural areas is practical up to 5mbps (more or less) • Increasing bandwidth to rural areas at rates of 100mbps is not going to happen in the foreseeable future • Compression will have a positive impact on quality of care and cost

7. Challenging the Status Quo • Lossy compression does NOT degrade image quality and can be used safely in daily practice!

8. The Canadian Approach to Driving Change • Commissioned 2 independent reviews of the literature • To assess the degree of research conducted in the evaluation of lossy compression • To determine whether a consensus of opinion exists among those who have evaluated the effect of lossy compression on diagnostic image quality • Conclusion • Lossy compression is a clinically acceptable option for the compression of medical images • The extent of allowable lossy compression ratio is dependent on the modality of the image and the nature of the imaged pathology and anatomy

9. The Canadian Approach to Driving Change • Commissioned 2 independent legal reviews • To assess the legal risk of adopting lossy compression • Conclusion • If the professional body adopts lossy compression as a standard of practice, and • If institutions deem the use of lossy compression provides economic and practical operational benefits as well as contributes to better quality care, • Then: the exposure to legal risk is no greater than with current practice. • The key presumption, however, is that the use of lossy compression does not impact the visual quality of an image

10. The Canadian Approach to Driving Change • Commissioned 1 regulatory review • To assess regulatory constraints in Canada, USA, EU and Australia • Conclusion • No statements preventing or endorsing the use of irreversible compression • Commissioned an economic analysis • To assess the financial benefit to Canada in using lossy compression • Conclusion • Potential storage cost savings of C$100 million annually

11. The Canadian Approach to Driving Change • Commissioned clinical evaluation • To assess the impact of lossy compression on visual quality • To develop guidelines for use of lossy compression within Canada • In Progress…completion targeted for end 2006

12. The Canadian Approach to Driving Change • Evaluation Project Scope: • Evaluate the impact of JPEG and JPEG 2000 lossy compression at “safe” compression ratios • Large matrix images 25:1 • Small matrix images 10;1 • Evaluation Project Protocol: • Diagnostic accuracy with ROC analysis • Original Revealed First Choice Just Noticeable Difference • 27 different sessions, with 3 reviewers for each • 81 radiologists from all across Canada • Sample size for each session will be 60 to 80 images. • 5 modalities: CR/DR, CT, US, MR, NM • 7 radiological areas: Angio, Body, Breast, Chest, MSK, Neuro, Pediatrics)

13. The Canadian Approach to Driving Change • Solicited Regional Health Authority Administrations • To declare the use of lossy compression a matter of public policy and resource allocation • In Progress • Fraser Health Authority (largest HA in Canada) has made such a declaration • In discussion with Provincial Health Ministries

14. Conclusion • We expect CAR to formally endorse lossy compression as a standard of practice by year end • We expect most Provincial health ministries to declare the use of lossy compression as a matter of public policy and resource allocation by end of 2007 • We will declare DICOM JPEG, JPEG2000 and JPIP as pan-Canadian standards • Canada has a Standards Collaboration Process for declaring standards for the pan-Canadian EHR • We will implement a reference system to serve as: • An open source test harness • A standards compliance tool

15. Questions?