M.Sc Thesis | |
M.Sc Student | Ben-Harim Tal |
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Subject | Quantification of Perfusion in an Experimental Model Using Sub-Harmonic Contrast Doppler |
Department | Department of Biomedical Engineering | Supervisors | PROFESSOR EMERITUS Dan Adam |
ASSOCIATE PROF. Amir Landesberg |
The hypothesis of this study
was: Blood flow in the microcirculation can be assessed by US-induced
destruction and measurements of refilling curves of Ultrasound Contrast Agents
(UCA), acquired using a new modality -Subharmonic color Doppler (SCD). The
goals of the study were: To quantify perfusion at low velocities using UCA and
SCD with different vessel widths and contrast microbubbles concentrations. The
experiments were performed on two flow phantoms: A 1.2mm tube and Perfusion
Dialysis cartridge. With both phantoms, refilling curves were obtained using
different UCA concentrations, and different flow rates. Another experiment was
performed to assess the influence of the emission power. The relation between
color area and time interval was assumed to follow the function: .
The model provided an excellent fit to the obtained data (r>0.98), in all experiments
with both phantoms. Higher flow rates correspond to faster replenishment with a
steeper slope of the replenishment curve and to a higher β value. An
excellent correlation (r>0.9) between flow rate and β values was found.
The results of the experiments made with both phantoms, demonstrate that there
are no significant differences between the slopes (P>0.05), but in the elevation
(P<0.05) of the regression lines. The impact of the emission power on
replenishment kinetics: the values of both parameters A and β increased
significantly (P<0.001) with increasing MI, approaching a plateau value at
the higher MI’s. Our main finding is that it is
possible to assess blood flow in the microcirculation using SCD.