220
C. Blazek and V. Blazek
variation and influencibility of tissue perfusion. The PPGI software can automatically
calculate the perfusion intensity for a selected frequency range and for every part
of the recorded skin surface and visualize these results—pixel per pixel—in a new
kind of color-coded multidimensional PPGI perfusion maps. Besides the mapping of
the heartbeat related perfusion intensity, also parameters related to other perfusion
rhythmicity behavior can be visualized, e.g., vasomotion activity.
Especially, in context with standardized dermatological tests (prick test, dermograpraphometry test), photoplethysmography imaging offers new possibilities for the
noninvasive functional assessment of the “multi-spectral” dermal perfusion status.
It not only permits contactless data acquisition (also perfusion studies in wounds are
now possible) but also provides additional spatial resolution which allows to directly,
quantitatively compare the dermal perfusion in different skin regions. On the other
side, the contactless measuring principle can often lead to disturbing artifacts, when
the measurement object is moving relative to the camera.
There are different algorithmic methods to detect and minimize existing movements in the original PPGI image sequences. They are based on, for example, the
principle of the pattern search (block matching) and iterative approximation method
for motion estimation. In a further step, each frame of the video sequence PPGI can
then be compensated by using the calculated motion vector field.
From our preliminary findings, evident distinctions in rhythmical perfusion
patterns between normal skin, diseased skin, and skin under medicament provocation
were found:
• In normal (physiological) skin, different perfusion rhythms are observed, for
example, arterial blood volume pulse (heart rate) but also respiratory synchronous
rhythms and rhythms with other lower frequencies;
• in the area of the treated skin or skin wounds, the heart synchronous perfusion
rhythms are dominant, all other perfusion rhythms with lower frequencies are
more or less attenuated (or masked?);
• we found a highly spatially distributed increase in the tumor perfusion;
• under Finalgon or histamine provocation, the amplitude of the arterial blood
volume pulse increases significantly;
• due to the contactless measuring strategy, motion-induced artefacts can occur and
should be algorithmically compensated.
References
1. A.B. Hertzman, The blood supply of various skin areas as estimated by the photoelectric
plethysmograph. Amer. J. Physiol. 124, 329–340 (1938)
2. A.B. Hertzman, J.B. Dillon, Applications of photoelectric plethysmography in peripheral
vascular diseases. Amer. Heart J. 20, 750–761 (1940)
3. A. Fronek, Noninvasive Diagnostics in Vascular Diseases (Mc Graw-Hill, New York, 1989)
C. Blazek and V. Blazek
variation and influencibility of tissue perfusion. The PPGI software can automatically
calculate the perfusion intensity for a selected frequency range and for every part
of the recorded skin surface and visualize these results—pixel per pixel—in a new
kind of color-coded multidimensional PPGI perfusion maps. Besides the mapping of
the heartbeat related perfusion intensity, also parameters related to other perfusion
rhythmicity behavior can be visualized, e.g., vasomotion activity.
Especially, in context with standardized dermatological tests (prick test, dermograpraphometry test), photoplethysmography imaging offers new possibilities for the
noninvasive functional assessment of the “multi-spectral” dermal perfusion status.
It not only permits contactless data acquisition (also perfusion studies in wounds are
now possible) but also provides additional spatial resolution which allows to directly,
quantitatively compare the dermal perfusion in different skin regions. On the other
side, the contactless measuring principle can often lead to disturbing artifacts, when
the measurement object is moving relative to the camera.
There are different algorithmic methods to detect and minimize existing movements in the original PPGI image sequences. They are based on, for example, the
principle of the pattern search (block matching) and iterative approximation method
for motion estimation. In a further step, each frame of the video sequence PPGI can
then be compensated by using the calculated motion vector field.
From our preliminary findings, evident distinctions in rhythmical perfusion
patterns between normal skin, diseased skin, and skin under medicament provocation
were found:
• In normal (physiological) skin, different perfusion rhythms are observed, for
example, arterial blood volume pulse (heart rate) but also respiratory synchronous
rhythms and rhythms with other lower frequencies;
• in the area of the treated skin or skin wounds, the heart synchronous perfusion
rhythms are dominant, all other perfusion rhythms with lower frequencies are
more or less attenuated (or masked?);
• we found a highly spatially distributed increase in the tumor perfusion;
• under Finalgon or histamine provocation, the amplitude of the arterial blood
volume pulse increases significantly;
• due to the contactless measuring strategy, motion-induced artefacts can occur and
should be algorithmically compensated.
References
1. A.B. Hertzman, The blood supply of various skin areas as estimated by the photoelectric
plethysmograph. Amer. J. Physiol. 124, 329–340 (1938)
2. A.B. Hertzman, J.B. Dillon, Applications of photoelectric plethysmography in peripheral
vascular diseases. Amer. Heart J. 20, 750–761 (1940)
3. A. Fronek, Noninvasive Diagnostics in Vascular Diseases (Mc Graw-Hill, New York, 1989)