Early detection of complete vascular occlusion in a pedicle flap model using quantitative [corrected] spectral imaging.
BACKGROUND
Vascular occlusion after tissue transfer is a devastating complication that can lead to complete flap loss. Spatial frequency domain imaging is a new, noncontact, noninvasive, wide-field imaging technology capable of quantifying oxygenated and deoxygenated hemoglobin levels, total hemoglobin, and tissue saturation.


METHODS
Pedicled fasciocutaneous flaps on Wistar rats (400 to 500 g) were created and underwent continuous imaging using spatial frequency domain imaging before and after selective vascular occlusion. Three flap groups (control, selective arterial occlusion, and selective venous occlusion) and a fourth group composed of native skin between the flaps were measured.


RESULTS
There were no statistically significant differences between the control flap group and the experimental flap groups before selective vascular occlusion: oxyhemoglobin (p=0.2017), deoxyhemoglobin (p=0.3145), total hemoglobin (p=0.2718), and tissue saturation, (p=0.0777). In the selective arterial occlusion flap group, percentage change in total hemoglobin was statistically different from that of the control flap group (p=0.0218). The remaining parameters were not statistically different from those of the control flap: percentage change in oxyhemoglobin (p=0.0888), percentage change in deoxyhemoglobin (p=0.5198), and percentage change in tissue saturation (p=0.4220). The selective venous occlusion flap group demonstrated changes statistically different compared with the control flap group: percentage change in oxyhemoglobin (p=0.0029) and deoxyhemoglobin, total hemoglobin, and tissue saturation (p<0.0001).


CONCLUSIONS
Spatial frequency domain imaging provides two-dimensional, spatially resolved maps of tissue oxyhemoglobin, deoxyhemoglobin, total hemoglobin, and tissue saturation. Results presented here indicate that this can be used to quantify and detect physiologic changes that occur after arterial and venous occlusion in a rodent tissue transfer flap model. This portable, noncontact, noninvasive device may have a high clinical applicability in monitoring postoperative patients.
Orange and Irvine, Calif. From the Department of Surgery, the Aesthetic and Plastic Surgery Institute, and the Beckman Laser Institute and Medical Clinic, University of California, Irvine, and Modulated Imaging, Inc., Beckman Laser Institute Photonic Incubator, Irvine.
Michael R
MR
Pharaon
Thomas
T
Scholz
Scott
S
Bogdanoff
David
D
Cuccia
Anthony J
AJ
Durkin
David B
DB
Hoyt
Gregory R D
GRD
Evans
D000465:Algorithms; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D004195:Disease Models, Animal; D006083:Graft Occlusion, Vascular / Q000175:diagnosis*; D006452:Hemoglobinometry; D006454:Hemoglobins / Q000378:metabolism*; D010108:Oxyhemoglobins / Q000378:metabolism*; D010865:Pilot Projects; D051381:Rats; D017208:Rats, Wistar; D013524:Surgical Flaps / Q000098:blood supply*; D041622:Tomography, Optical; D020246:Venous Thrombosis / Q000175:diagnosis*
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin