Presentation on theme: "Dynamic holographic imaging of the beating heart. How far to go ? Patrick Hunziker, MD ICU / Cardiology / Physics in Medicine Research Group Basel University."— Presentation transcript:
Dynamic holographic imaging of the beating heart. How far to go ? Patrick Hunziker, MD ICU / Cardiology / Physics in Medicine Research Group Basel University Hospital, Switzerland Massachusetts General Hospital, Boston USA Massachusetts Institute of Technology, Cambridge USA
Display of Multidimensional Echo Data M-mode Static 2D dynamic 2D surface-rendered 3D true 3D/4D +/- color # of dimensions 234 Info content: Reporting: 0.2 MB page 2 MB videotapes digital loops ? print 20-100 MB ?
History of Echo Display DimensionDisplay type timestrip 1954 space X 1960s space Y 2D still image 1970s 2D movie 1980s flow field 2D color movie 2000s space Z hologram
What is holography ? interference pattern object beam reference beam holography = recording of data by light diffraction/interference photosensitive substrate fix pattern in substrate reference beam reconstructed object
Kinds of holography optical holographydigital holography Aim To explore the ability ofholography to displaycardiac motion space X space Y space ZHologram TIME Conventional hologram Dynamic heart motion hologram conventional holograms contains multiple perspective views dynamic heart motion holograms contains multiple timeframes static 3D image change of viewing angle change of perspective static 3D image change of viewing angle change of perspective moving object change of viewing angle change of timepoint Conventional Holography Dynamic Holography Production of Holograms: Optical technique: Computational technique: Laser Object reference beam object beam interference pattern light sensitive substrate virtual object calculation of hypothetical interference pattern HOE Laser light sensitive substrate Methods Echocardiogram HP Sonos 2500 optical disk reformatting PC HP software filter,crop,contrast NIH image One-step digital hologram printing postprocessing data acquisition Viewing of dynamic heart holograms Characteristics of dynamic heart holograms: Resolution / Sharpness: currently: 640*480 pixels*32 time-frames. practically limited by computer power. theoretically limited only by wavelength of laser. no distortion Color: B/W & color images Printing time: Conventional methods: days to weeks. Prototype one-step laser-printers: minutes. additional applications of dynamic heart holograms: -2D echo + motion +color Doppler -rendered 3D + motion -true 3D + motion -true 3D +color Doppler + motion Advantages of dynamic heart holograms: display & reporting of echocardiograms: -a single page: anatomy, contractile function, valvular function & Doppler -no need for viewing stations simple archiving scheme: -a single page contains complete original image info Holographic representation of heart motion -is feasible -allows printing & display of the complete heart cycle on a two-dimensional medium. This novel technique has the potential to improve visualisation and archiving of echocardiographic imaging. MEDIS Hypothesis: Computational, dynamic holography can be applied to echo imaging of cardiac motion in a variety of clinical states Laser LCD Hunziker P, Circulation 1998, in print
types of holography: optical vs computational real object Laser reference beam object beam interference pattern light sensitive substrate virtual object computation of virtual interference pattern HOE light sensitive substrate Laser LCD illumination of real object with light necessary virtual representation of object is enough
types of holography holographic storage interferometry
types of holography display holography holographic video
conventional display holography: static representation of 3D objects multiple perspective views conventional hologram: static 3D shape
prior uses of holography in medicine Display holography Create static 3D representation from X-rays (Redman, Nature 1968) holographic interferometry: nondestructive surface testing of heart valve prostheses (Zarubin, J Heart Valve Dis 1993)
conventional holography in cardiology Vannan et al. J Am Soc Echocardiogr. 1995;8:567–575 Excised bovine heart use ultrasound to create static, volumetric multiplexed display hologram
In echo, motion is key information Goal: to explore the ability of holography to display heart motion by integration of space and time dimensions into digital print holograms
Display of motion by dynamic holography static 3D image change of viewing angle change of perspective Conventional Holography moving object change of viewing angle change of timepoint Dynamic Holography
Methods Echocardiogram HP Sonos 2500 data acquisition optical disk reformatting PC HP software MEDIS filter,crop,contrast NIH image software postprocessing One-step digital hologram printing UNIX
Viewing of dynamic heart holograms
dynamic (2d + time) hologram from standard echo images Hunziker, Circulation 1999
Results - hologram printing pipeline - real-time preprocessing - printing time 10 min on prototype holographic printer ( technology similar to DVD reader/writer ) - plastic sheet of 0.3mm thickness - size 7x10cm - resolution >>> current echo machines - 640 x 480 pixels x 25 timeframes
Advantages of dynamic heart holograms display & reporting of echocardiograms: -a single page: anatomy, contractile function, valvular function & Doppler -no need for viewing stations simple archiving scheme: -a single page contains complete original image info
Summary Holographic representation of heart motion -is feasible -allows printing & display of the complete heart cycle on a two-dimensional medium -can convey 3D anatomy + motion + flow in a single printout This novel technique has the potential to improve visualisation, reporting and archiving of echocardiographic imaging.
parallax in holography -> representation of 4 kinds of image information horizontal parallax vertical parallax Smith, MIT Media Lab
Work in progress: Exploitation of independence of horizontal and vertical parallax in digital holograms => combination of true (volumetric) 3D + motion
work in progress II 3 laser wavelengths for RGB recording full color holograms -> 3D + time + flow in a simple printout ! Hunziker et al Smith SL, MIT Media Lab
Outlook: holographic video State of the art: - a few prototypes worldwide - still low resolution - 15 fps - monochrome - need for huge bandwidths -> display of moving 3D echo in the future ?
Will display holography ever play a role in echocardiography ? Pro: -currently, working with 3D echo is tedious -> no widespread application outside the research lab. -inherent problems of 3D display on a 2D screen -hologram printer technology ~ level of DVD ROM -capability of upcoming holographic video systems Contra: availability of hologram printers will the future society be all digital and all virtual ?
Thanks to My teachers in echocardiography Osmund Bertel, Zurich Dieter Burckhardt, Basel Peter Buser, Basel Mike Picard, Boston Bob Levine, Boston Arthur E Weyman, Boston My family for support The Swiss National Research Foundation