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C. Blazek and V. Blazek
An algorithm implemented in PPGI software can now place an ROI of a specified
size on one edge of the image sequence and then scan the whole region from there. For
each position, the total PPGI signal variation is obtained and the functional perfusion
parameter PI PPGI is calculated. According to this value, the actual ROI is colorised
by a specified colormap. The ROI is then moved to an adjusted position and again
colorized; this process is repeated until the whole skin area is assessed. The Fig. 12.2
and Fig. 12.3 visualize this algorithm. The resulting PPGI perfusion map does not
depend on morphological skin parameters anymore but only represents functional
data of the dermal perfusion status.
By choosing different filter parameters, for example, the respiration-dependent
perfusion dynamics of the skin can be visualized with spatial resolution [9, 10].
12.4 Selected Results
12.4.1 New Insights into the Phenomenon of Distributed
Dermal Blood Circulation
The mentioned algorithms have been tested on different PPGI recordings. The
achieved potential of the computer-aided mapping procedure is illustrated in
Fig. 12.2. In this first test, the perfusion effect of treatment with vasoactive liniment (Finalgon
® Crème) inside of a marked skin region on the lower arm is assessed
(healthy control in horizontal position; 120 s video sequence starting 15 min after
local application). The treated skin regions exhibit an increase in perfusion intensity
of up to 600%.
The complete (virtual) perfusion map of the lower arm related to the amplitude
to the local blood volume pulse is shown in Fig. 12.3 and is independent of the skin
surface structure and morphology, as mentioned above.
The next clinical PPGI application example in dermatology shows a PPGI perfusion map of a forearm area taken nearly 2 min after mechanical irritation along the
arm axis (Fig. 12.4). This is a functional, quantitative alternative to the classical
dermographometry examination [11–13]. Following the heavy force application, the
heartbeat synchronous perfusion changes in the stressed skin area were considerably
increased (physiological reaction) for a limited time period (factor 2.2, if the mean
perfusion intensity value in ROI 2 is compared to the value in ROI 1).
Figure 12.5 shows the distributed microcirculation situation of a malignant skin
tumor in the heel area. The microcirculation of human skin tumors can be visualized
with state-of-the-art noninvasive imaging methods (dermoscopy, capillaroscopy) and
with the laser Doppler fluxmetry (LDF). The distributed perfusion status can be
quantified also with laser Doppler perfusion imaging (LDPI), but not in all tumor
areas at the same time [14–16]. For the first time, this is possible using the introduced
PPGI device. To transilluminate deeper skin layers, LED near-infrared light with
wavelengths about 940 nm was used in this study. As can be seen in the PPGI
C. Blazek and V. Blazek
An algorithm implemented in PPGI software can now place an ROI of a specified
size on one edge of the image sequence and then scan the whole region from there. For
each position, the total PPGI signal variation is obtained and the functional perfusion
parameter PI PPGI is calculated. According to this value, the actual ROI is colorised
by a specified colormap. The ROI is then moved to an adjusted position and again
colorized; this process is repeated until the whole skin area is assessed. The Fig. 12.2
and Fig. 12.3 visualize this algorithm. The resulting PPGI perfusion map does not
depend on morphological skin parameters anymore but only represents functional
data of the dermal perfusion status.
By choosing different filter parameters, for example, the respiration-dependent
perfusion dynamics of the skin can be visualized with spatial resolution [9, 10].
12.4 Selected Results
12.4.1 New Insights into the Phenomenon of Distributed
Dermal Blood Circulation
The mentioned algorithms have been tested on different PPGI recordings. The
achieved potential of the computer-aided mapping procedure is illustrated in
Fig. 12.2. In this first test, the perfusion effect of treatment with vasoactive liniment (Finalgon
® Crème) inside of a marked skin region on the lower arm is assessed
(healthy control in horizontal position; 120 s video sequence starting 15 min after
local application). The treated skin regions exhibit an increase in perfusion intensity
of up to 600%.
The complete (virtual) perfusion map of the lower arm related to the amplitude
to the local blood volume pulse is shown in Fig. 12.3 and is independent of the skin
surface structure and morphology, as mentioned above.
The next clinical PPGI application example in dermatology shows a PPGI perfusion map of a forearm area taken nearly 2 min after mechanical irritation along the
arm axis (Fig. 12.4). This is a functional, quantitative alternative to the classical
dermographometry examination [11–13]. Following the heavy force application, the
heartbeat synchronous perfusion changes in the stressed skin area were considerably
increased (physiological reaction) for a limited time period (factor 2.2, if the mean
perfusion intensity value in ROI 2 is compared to the value in ROI 1).
Figure 12.5 shows the distributed microcirculation situation of a malignant skin
tumor in the heel area. The microcirculation of human skin tumors can be visualized
with state-of-the-art noninvasive imaging methods (dermoscopy, capillaroscopy) and
with the laser Doppler fluxmetry (LDF). The distributed perfusion status can be
quantified also with laser Doppler perfusion imaging (LDPI), but not in all tumor
areas at the same time [14–16]. For the first time, this is possible using the introduced
PPGI device. To transilluminate deeper skin layers, LED near-infrared light with
wavelengths about 940 nm was used in this study. As can be seen in the PPGI