Abstract 5282: Optical Coherence Tomography (oct) A New Method For In Vivo Imaging And Quantification Of Collateral Vessel Growth In Mice
Therapeutic augmentation of collateral vessel growth (arteriogenesis) is of particular clinical interest. Quantification of collateralization in small animal models is, however, difficult and the commonly used technique of Laser Doppler perfusion imaging (LDPI) has always been criticized, especially as determination of flow in the vascular system is infeasible. We hypothesized that the new technology of optical coherence tomography (OCT), a non-invasive high resolution tomography imaging technique, may constitute a valuable tool for in vivo imaging of the remodelling of an arteriole into a full collateral vessel in mice. The morphology of the collateral vessels in the adductor muscle was visualized by 3D imaging and the diameters of growing collaterals were determined after ligation of the left femoral artery of C57BL6 mice. The results were compared to the gold standard of LDPI and by histological workup. The diameter of collateral vessels in the adductor muscle measured by OCT increased from 28 μm before ligation to 112 ± 4 μm after 3 weeks (n= 5, p< 0.05). Histological workup of hind limb tissue sections approved the increase of collateralization. The ratio of collateral arteries (left/right) was calculated (each group n=7). It increased from 1.0 ± 0.05 (prior to ligation) to 1.35 ± 0.10 two weeks and 1.41 ± 0.08 three weeks after ligation (p< 0.05). Quantification of superficial skin perfusion by LDPI demonstrated a drop from 1.06 ± 0.06 (left/right ratio) before ligature to 0.37 ± 0.03 immediately after ligature, as well. However, skin perfusion recuperated completely within one week (1.01 ± 0.14) reaching even higher ratios in the ligated than in the unligated hind limb after 3 weeks (1.20 ± 0.29). OCT allows accurate quantification of collateral remodelling within the hind limb of mice after ligature of the femoral artery while the current standard of LDPI seems to rather quantify superficial skin perfusion.