In vitro measurement conditions for optical coherence tomography (OCT).
CONCLUSIONS
Tissue marking with soot-covered fine needles enables the optical coherence tomography (OCT) scanning plane to be localized within the histological specimen to an accuracy of approximately 50 microm. Tissue water content is an especially important parameter for in vitro measurements. Dehydration tends to produce an increase in surface reflections and a reduction in imaging depth.


OBJECTIVE
The aim of this in vitro study was to evaluate parameters relevant to the visualization and conservation process to allow optimal images to be generated for later differentiation between healthy and degenerated tissue in vivo.


METHODS
Various methods of marking samples were applied in vitro to achieve accurate overlaps of the OCT scanning plane and the corresponding section of the histological specimen. The influence of temperature and tissue water content was investigated using both porcine and human tissue. Samples were marked using fine needles, ablation craters generated by laser application, and colour markers introduced into the tissue.


RESULTS
It was demonstrated that the water content of tissue exerts a direct influence on OCT imaging, whereas above 15 degrees C temperature had no effect on image quality. With regard to the marking of samples, the best results were obtained using sooted fine needles.
Bornemann
J
J
Department of Otolaryngology, Medical University of Hannover, Hannover, Germany. bornemann@iht.rwth-aachen.de
Hagner
D
D
Brandenburg
R
R
Hauger
C
C
Wilkens
L
L
Lenarz
T
T
Heermann
R
R
D000273:Adipose Tissue / Q000033:anatomy & histology*; D000818:Animals; D044963:Biopsy, Fine-Needle; D001834:Body Water / Q000502:physiology; D006801:Humans; D007089:Image Enhancement; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D009339:Needles; D053260:Soot; D034421:Sus scrofa; D013696:Temperature; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000592:standards*
D053260:Soot