Digital storage of pathology slides on the Internet: techniques and issues Vincenzo Della Mea 1,...
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Transcript of Digital storage of pathology slides on the Internet: techniques and issues Vincenzo Della Mea 1,...
Digital storage of pathology slides on the Internet: techniques and issues
Vincenzo Della Mea1, Francesca Demichelis3,Vito Roberto2
1) Dept. of Medical Morphological Research, 2) Dept of Computer ScienceUniversity of Udine, Italy
3) ITC/Irst, Trento, ItalyPer vedere questa immagineoccorre QuickTime™ e undecompressore GIF.
MEDNET2001 - Udine, Italy
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Telepathology on the Internet
It’s a mammuth (frozen sections)
Fast diagnosis during surgery Needs realtime
main application: remote consultation Second opinion diagnosis On a peer-to-peer basis just like in traditional mail-based
consultation of expertsGrowing field: education
Access to microscope images without microscope
Self-learningQuality control
Proficiency testing
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Internet telepathology implementation
Store-and-forward Email Server-mediated (on the WWW) Proprietary tools
Realtime Remotely driven robotized microscope Videoconference-like tool
Della Mea V. Pre-recorded telemedicine. In: An introduction to telemedicine (Wootton R, Craig J eds.), RSM Press, London, 2000
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Acquisition devices: storage sizes
Resolution Storage size Compressed*
Analog cameras 800x600 1.4 MB 100 KB
Digitalphotocameras
1800x1200 6.3 MB 400 KB
Photoscanners 3400x2700 26.2 MB 1.7 MB
Digital glass slide Thousandsof images
1-5 GB ~300 MB
*Foran et al. Compression guidelines for diagnostic telepathology. IEEE Trans IT in Biomedicine, 1997; 1:55-60
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Human-computer interface problems
The usual computer screen has up to 1024x768-1600x1200 pixels; Images are larger than the display
The pathologist has specific habits coming from the use of the microscope, which are not often respected by computer systems
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.The pathologist’ behaviourDouble observation pattern:
First, a low magnification slide overview Then, a high magnification study of the
possibly diagnostic details (Tsuchihashi et al. The basic diagnostic approaches used in
robotic still-image telepathology. J Telemed Telecare 5(S1) (1999), 115-117)
Apart from cytology, useful details represent a minimum part of the total specimen area
Looking at images with a browser does not satisfy this constraints!
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Interaction with the glass slide
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.S&F Telepathology
Usually on selected imagesPractical, not expensive, but…
Limited: pathologists do not like diagnose on selected images (even when good diagnostic quality is demonstrated)
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Digital storage of Pathology slides
Idea: we acquire the whole glass slide using a high magnification objective
Issues: Maximum (useful) resolution Storage size - thousands of images!!! speed
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Microscope resolution
Depends on Numerical Aperture (NA) of the objective, and wavelength
At 100x, oil objective, up to 0.2 micron2 pixel/point => 10 pixel per micron
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Histological sample size
10 mm2 - 3 cm2
1cm2 = 10000 x 10000 micronThis corresponds to an image of:
100000x100000 pixels 10GB uncompressed 500 MB
safely compressed
Not easy to manage !
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Approaches
CD rom distribution Still more physical storage needed than the glass
slide
Online: exploitation of the double pattern used by pathologists (i.e., sending just what is needed) Need for protocols
Establishment of microscope-like interfaces
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Current status of storage
Very fashioned nowFolder-based storage
Dublin, Trento, Nikon(?)..
Proprietary, patented systems Flashpix BacusLab’s Webslide™
Proposals: Adapting DICOM
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Current status of protocols
Adapted from other uses IIP (Internet Imaging Protocol)
Open source protocols: iPath
(available on the Web, ipath.sourceforge.net)
Proposals: DICOM again?
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.IIP and telepathology
A possible correspondence: changing magnification ~ changing
resolution Moving the microscope stage ~image pan
Advantages: Slide overview available Transmission only of the needed details
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Standardization
One of the major lacks of telepathology is standards
A protocol is needed for dynamic telepathologyStatic and dynamic telepathology with the same
softwareSome extension would make the protocol
better, i.e., for managing focus or at least some focus plane
iPath? IIP? DICOM for virtual slides?
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.IIP in the Italian Network After these evaluations,
we recently added IIP access to images in all network databases
It is viewable with almost all Java-compliant browsers
Implementation: Apache (web server) Jserv (servlet engine) IIP reference
implementation running as an applet
Standard JPEG images
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The Trento SteMySys system
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.An iPath-based protocol
Mic. API Virtual Microscope Protocol
Stored cases
XML model of the robotized microscope features
Transport:•SOAP/XML_RPC•IP•HTTP•...
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Developments
Cytology needs more than one focus plane: IIP -as is- is not sufficient, need to extension
Client software: a separate slide overview might be useful (no need for protocol changes)
We are trying to develop a dynamic server for doing static as well dynamic telepathology with the same protocol) Starting from IIP and the iPath protocol
Per vedere questa immagineoccorre QuickTime™ e undecompressore GIF.Conclusions
Digital storage of glass slides seems promising for Education Quality control Sometimes telediagnosis
In the future, even as a substitute for legal storage of diagnostic material At present, glass is better than magnetic/optical
technologies...