How to deal with increasing imaging demand. Niek van der Putten Thoraxcentre ErasmusMC, Rotterdam, NL

Transcription

1 How to deal with increasing imaging demand. Niek van der Putten Thoraxcentre ErasmusMC, Rotterdam, NL

2 Background Cardiac imaging procedures: high grow rates Growth of advanced imaging techniques enormous growth in the amount of imaging data acquired Imaging data by volume the largest source of electronic health data Inaccessibility of prior studies is responsible for a significant number of duplicate studies (IHE) Most images often provided on portable media (CD, DVD) Long term archive often on CD-ROM. Shelf life of image data?

3 Changes in Image landscape I Angio: 512*512 (8 bits) Flat panel detectors 1024*1024 (12 bits) Rotational angio

4 Changes in Image landscape II New medical procedures (e.g.: Aortic valve replacement) New image modalities MRI MSCT IVUS OCT

5 Present storage and display of angios Long-term storage : CD-ROMs (2) or PACS (3) Short-term storage: Cathlab (1) Diagnostic display: dedicated monitors (4) Review display: consumer PC-monitors (5)

6 THOPACS (angio-pacs): DICOM CD PC angiography suites and administration 100 Mb/sec viewing station PC image server RAID disk system (1400 GB) 100 Mb/sec viewing station PC PC Cathlab outpatient clinic surgery dept. clinic

7 Angiographic system PACS I Issues: Uploading strategy Archive: Retention period Short term and long term Cathlab or Cardiology or Hospital or Enterprise archive Downsizing of images Compression of images Technical infrastructure Review images: angio, angio + report, multimedia

8 Angiographic system PACS : uploading strategy Alternative methods: 1. Angiographic system CD PACS entire study 2. Angiographic systeem PACS real time every run 3. Angiographic systeem PACS

9 Archive related aspects 1. Medico-legal issues: retention period 2. Compression, downsizing, reduction of images 3. Archive: Cathlab vs Cardiology vs Hospital vs Enterprise or regional 4. Short term vs long term archive 5. Technical infrastructure: network, diagnosis vs review workstations, servers, storage media (CD, Disk, Tape)

10 Problems with CD 1. Exchange of images Inconvenience and failures for producers and consumers of images Guidelines are out-of-date: 512*512 (8 bits) angiographic images Standardized compression ratio s are based on those images. Advice: use only lossless JPEG compression (ACC and ESC; Nissen, Simon 2000) (Long term) storage Shelf life of image data (2-70 years). Dependency: Silber or Gold layer (fast vs slow erosion) Speed of writing images. High speed Low shelf life Sun, heath, vertical/horizontal storage Quality of CD 650 Mb better than 700 Mb CR-R better than CD-RW Off line availability

11 (Legal) retention period of images 1. Determines minimal availability period of the images Digital image retention periods vary from country to country and are typically based upon the age of the patient. 2. Adults between 5 and 15 years with extremes of 30 years. 3. Costs: 60 Keuro per year (production: 3 Tb per year, retention period: 10 years, 2000 Euro per Tb per year). 4. Costs requiring personnel, power, cooling, and redundant infrastructure components, plus the cost for a second secure data center for disaster recovery. 5. Same quality of diagnostic information achieved in the original?!?!?

12 Compression, downsizing, reduction of images (Clinical) reduction of images: clinically relevant runs, mid run images Downsizing: 1024*1024*12bits 512*512*8bits?? NO!! Lossless vs lossly compresion

13 Compression I Angio mage reduction 50% %

14 Compression II Standard (tested for 512*512*8): JPEG-lossless (50%); evaluated in late 90 s (ESC and ACC) JPEG-lossy; evaluated in late 90 s (ESC and ACC) not suitable for 12 bits images JPEG-2000: not evaluated for angio s; employed since 2003 Good compression, but slow JPEG-LS: new Dicom-standard; not yet evaluated for angio s Good and fast compression

15 Compression III Two Biplane images (1024*1024*12 bits; framerate = 15) Compression #bits per 2 frames #bits per second Raw=JPEG-lossless 32 Mbit 480 Mbit JPEG (QF=85%; 8 bits) 2.5 Mbit 36 Mbit JPEG2000 (QF=85%; 12 bits)? Mbit? Mbit

16 Archive Cathlab: short (and long term) term angio archive Cardiology: short (and long term) term archive for angio, echo, (IVUS, OCT) and EFO, Nuclear archives Hospital: cardiology archives and MRI, MSCT, Chest images Enterprise: multicenter Future: -multimodality diagnostics -multicentered Required: standardized imaging and reporting

17 Changes in Image landscape III Diagnosis and Triage patients: Multimedia Show?

18 Storage strategy Raw data Raw data Lossless compressed image archive Thopacs servers Condensed data Lossy compressed image archive On-line long term archive

19 Technical infrastructure 1. Network Per year: 100 Mb: suitable for 512*512*8 lossless and lossy images suitable for 1024*1024*12 lossy images Preferably not for >=1024*1024*12 lossless images 1 Gb 2. Monitor Diagnosis: Dicom calibrated monitors No: home monitor or standard beamer Review: good monitor (or beamer and screen) 3. Archive media: SAN or redundant storage 5*9 or 7*24 support

20 THOPACS (clinical) : general architecture Cathlab ECHO THOPACS servers SAN Referral hospital Evocs DVD-publisher

21 Discussion 1. Compression evaluation: JPEG-LS, large images!! 2. Development of an archive of well-characterized representative digital angiographic images. 3. Standards for image exchange and reporting 4. Biplane images OR 5. Technical infrastructure challenges

22 FUTURE: storage DICOM-ECG s (from referral hospitals)