In vivo real time monitoring of vasoconstriction and vasodilation by a combined diffuse reflectance spectroscopy and Doppler optical coherence tomography approach.
OBJECTIVE
A combined diffuse reflectance (DR) spectroscopy and doppler optical coherence tomography (DOCT) approach may offer a powerful means for assessment of tissue function, and potentially provide a way for earlier cancer detection through non-invasive local blood supply measurements. The goal of the study was to compare a DR-derived blood-content-related index to a measure of local blood supply flow as furnished by DOCT during manipulations with blood circulation (vasoconstriction and vasodilation), investigate similarities and differences, complementarity of techniques, and then applying these results to the underlying biology.


METHODS
Simultaneous DR-DOCT measurements of local blood supply were conducted during drug and mechanically-induced vasoconstriction and vasodilatation on an externalized intact rat gut in vivo. A simple heuristic metric, termed Blood Supply Index was derived from the spectroscopic DR data. This metric variance due to mechanical and pharmacological manipulation of the local blood supply was recorded, and compared with that of two DOCT-derived metrics, namely normalized blood velocity (v(rel)) and blood vessel diameter (D).


CONCLUSIONS
During vasoconstriction and vasodilatation, the local blood response was successfully visualized by both DOCT and DR metrics and a reproducible correlation was found between these two measurements. A combined DR-DOCT approach may evolve into a technologically-viable method for cross-validation of the derived haemodynamic metrics, yielding a more reliable functional tissue assessment tool for accurate cancer diagnosis and staging.
Douplik
A
A
Ontario Cancer Institute/Princess Margaret Hospital/University Health Network, Toronto, Canada. alexandre.douplik@aot.uni-erlangen.de
Morofke
D
D
Chiu
S
S
Bouchelev
V
V
Mao
L
L
Yang
V X D
VX
Vitkin
A
A
D000818:Animals; D007583:Jejunum / Q000098:blood supply*; D008297:Male; D008833:Microcirculation / Q000502:physiology; D051381:Rats; D011917:Rats, Inbred Lew; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013057:Spectrum Analysis; D041623:Tomography, Optical Coherence; D014661:Vasoconstriction / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*