Optimization of the method for assessment of brain perfusion in humans using contrast-enhanced reflectometry: multidistance time-resolved measurements.
The aim of the study was to determine optimal measurement conditions for assessment of brain perfusion with the use of optical contrast agent and time-resolved diffuse reflectometry in the near-infrared wavelength range. The source-detector separation at which the distribution of time of flights (DTOF) of photons provided useful information on the inflow of the contrast agent to the intracerebral brain tissue compartments was determined. Series of Monte Carlo simulations was performed in which the inflow and washout of the dye in extra- and intracerebral tissue compartments was modeled and the DTOFs were obtained at different source-detector separations. Furthermore, tests on diffuse phantoms were carried out using a time-resolved setup allowing the measurement of DTOFs at 16 source-detector separations. Finally, the setup was applied in experiments carried out on the heads of adult volunteers during intravenous injection of indocyanine green. Analysis of statistical moments of the measured DTOFs showed that the source-detector separation of 6 cm is recommended for monitoring of inflow of optical contrast to the intracerebral brain tissue compartments with the use of continuous wave reflectometry, whereas the separation of 4 cm is enough when the higher-order moments of DTOFs are available.
Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, 4Ks. Trojdena Street 02-109 Warsaw, Poland.
Daniel
D
Milej
Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, 4Ks. Trojdena Street 02-109 Warsaw, Poland.
Dariusz
D
Janusek
Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, 4Ks. Trojdena Street 02-109 Warsaw, Poland.
Anna
A
Gerega
Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, 4Ks. Trojdena Street 02-109 Warsaw, Poland.
Stanislaw
S
Wojtkiewicz
Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, 4Ks. Trojdena Street 02-109 Warsaw, Poland.
Piotr
P
Sawosz
Warsaw Praski Hospital, Department of Intensive Care and Anesthesiology, 67 Al. Solidarnosci Street, 03-401 Warsaw, Poland.
Joanna
J
Treszczanowicz
Warsaw Praski Hospital, Department of Intensive Care and Anesthesiology, 67 Al. Solidarnosci Street, 03-401 Warsaw, PolandcUppsala University, Department of Surgical Sciences/Anesthesiology and Intensive Care, 751 85 Uppsala, Sweden.
Wojciech
W
Weigl
Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, 4Ks. Trojdena Street 02-109 Warsaw, Poland.
Adam
A
Liebert
D000328:Adult; D001783:Blood Flow Velocity; D001921:Brain; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000493:pharmacokinetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D055420:Perfusion Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
D003287:Contrast Media