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Laser Doppler Imaging
Transcript of Laser Doppler Imaging
Blisters 2 superficial - medium - deep 1 Red skin
Pain st rd 3 Epidermal - Dermal - Full thickness Whitening
Loss of sensation Epidermal - Dermal - Full thickness Costs? 3000 - 5000 USD per day for patient.
> 10% (children)
> 15 % (adults) Total Burnt
Surface Area 1% hospitalized For burns if: Source: http://www.jaapa.com/circumferential-electrical-contact-burn-of-a-finger/article/137571/ 40 000 hospitalizations / year Reference: http://www.who.int/surgery/publications/Burns_management.pdf Circumferal Airways Skin grafting Cool Clean Remove necrotic tissue ! Hypothermia Antibiotics A Project in Selected chapters of Medical Technology, 2010 Vu Thanh-Hieu Nguyen
Trygve Utstumo Laser Doppler Technology State of the art History 1964, Cummins, Knable and Yeh measured velocity
1975, Durst and Zaré proposed to measure particle size via the phase.
1981, Flögel "Investigation of particle velocity and particle size using Laser Doppler anemometer" http://video.google.com/videoplay?docid=-73872844921836910&ei=EuOqSqy2K9DvlQeUyqCuAw&q=doppler&emb=1&so=2 Video demonstrating the principle: LDI Basics LSI Laser Speckle Imaging Depth: 1 - 2 mm
Point or line scanning Depth: 0.6 mm max
Cannot differentiate velocity from concentraion http://www.nmr.mgh.harvard.edu/~adunn/speckle/Speckle_Imaging_of_CBF.html MoorLDLS - Line scanner 64 pixels per line
100 ms per line
~ 5 seconds imaging Visual inspection Will the burn heal? Innovation Custom CMOS chip
Real-time processing Portable LDI 20fps at 512x512 pixels Ready in October 2010
FDA and CE approved
Our assesment LDI
Slow (requires scanning)
Depth of about 1-2mm
Depth limited to 0.6mm
Cannot distinguish velocity and concentration
Real-Time Aïmago LDI
LDI precision and depth
Portable and Real-time
Clinical trials remains
The Aimago device seems superior. A spin-off from EPFL Based on CMOS technology from Laboratoire d’Optique Biomedicale, led by Prof. Theo Lasser.
Aïmago SA CEO: Michael Friedrich
Located at EPFL scientific park Highly improved accuracy of Burn depth assesment: Intraoperative Brain Imaging Further applications: 70 % Clinical ass.
97 % LDI assisted Burns 27 (2001) 233– 239, An audit of the use of laser Doppler imaging (LDI) in the assessment of burns of intermediate depth, Sarah A. Pape a,*, Costas A. Skouras b, Phillip O. Byrne b
LDI, Blood perfusion image Aïmago expects a market share of 7%
by 2013, thus $57.4m of $820m.
Michael Friedrich, CEO Technology core advantage
In close cooperation with CHUV and others for ongoing clinical trials. Potential pitfalls Product launch announced for October 2010, will it be ready?
Advantages of LDI
Monitor healing in
intensive care. For the clinical part, we would like to address Sensitivity and Specificity. Sensitivity is the rate of true positives, here that means that the patient really need surgery and specificity is the rate of true negatives, the patients that will heal on their own without any need for skin grafts. In Pape’s audit, it was demonstrated that the specificity of laser Doppler was about 95% and a sensitivity of 100%. These are amazing figures when you consider clinical judgment to be around 71% and 66% respectively. This means that we can avoid surgery for 50% more patients by determining that they would heal by themselves. It also means that the technology catches 100% of people requiring surgery against “only” 71% without LDI. Holland et al.6 judged LDI to be 90% sensitive and 96% specific. We can conclude that the device is ideal for determining the need to operate or not.