Photothermolysis of blood vessels using indocyanine green and pulsed diode laser irradiation in the dorsal skinfold chamber model.
OBJECTIVE
For the treatment of vascular lesions, the use of laser light absorbed by the endogenous chromophore hemoglobin may still be improved.


METHODS
Laser treatment (lambda(em) = 805 nm; fluence rate: 106 kW/cm2; fluence: 3.2 J/cm2 (3 milliseconds)), of blood vessels directly after i.v. application of indocyanine green (ICG) (ICG-concentration: 0, 2, or 4 mg/kg body weight (b.w.)) (n = 14,117) was investigated in the skinfold chamber model. Vessel diameters (1-351 microm) were measured using intravital fluorescence microscopy up to 24 hours following irradiation. Histology was taken 1 or 24 hours after irradiation. Results were compared to a mathematical model based on the finite element method.


RESULTS
The reduction of blood vessel perfusion was proportional to ICG-concentration and pulse duration; only a 30 milliseconds pulse duration (2 or 4 mg/kg b.w. ICG-concentration) induced a loss of perfusion even of blood vessels with a diameter <30 microm. Histology revealed photocoagulation of blood vessels up to 24 hours. Results were in agreement with mathematical calculations.


CONCLUSIONS
ICG-mediated laser irradiation induces irreversible photocoagulation of blood vessels of all diameters in this model.
Babilas
Philipp
P
Department of Dermatology, Regensburg University Medical Center, 93042 Regensburg, Germany. philipp.babilas@klinik.uni-regensburg.de
Shafirstein
Gal
G
Baier
Jürgen
J
Schacht
Vivien
V
Szeimies
Rolf-Markus
RM
Landthaler
Michael
M
Bäumler
Wolfgang
W
Abels
Christoph
C
D000818:Animals; D004396:Coloring Agents / Q000494:pharmacology*; D006224:Cricetinae; D062109:Dermatologic Surgical Procedures; D020342:Finite Element Analysis; D007208:Indocyanine Green / Q000494:pharmacology*; D017075:Laser Coagulation / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008856:Microscopy, Fluorescence; D012867:Skin / Q000098:blood supply
D004396:Coloring Agents; D007208:Indocyanine Green