[Color Doppler imaging in the study of normal orbital vessels and its hemodynamics].

Color Doppler Imaging (CDI) is a recent development in ultrasonography, which can display simultaneously two dimensional images of structure and Doppler evaluation of blood flow. Using the technique, we examined 74 normal eyes. Orbital vessels including ophthalmic artery (OA), posterior ciliary arteries (PCA), center retinal artery (CRA) and central retinal vein (CRV) could be located to make Doppler spectrum analysis and quantification of hemodynamics. Blood velocity (Unit cm/s) in these vessels was obtained as following: the average peak systolic flow velocity for OA was 31.9 +/- 5.01; for PCA, 14.74 +/- 3.85 and for CRA, 11.5 +/- 2.45. The time-averaged maximum velocity for OA was 14.91 +/- 1.83 and for PCA, 8.09 +/- 2.00 and for CRA, 5.78 +/- 1.14. The end-diastolic velocity for OA was 9.04 +/- 1.15; for PCA, 5.46 +/- 1.61 and for CRA, 3.73 +/- 1.06. The resistivity indices for OA were 0.715 +/- 0.04 and for PCA, 0.63 +/- 0.04 and for CRA, 0.68 +/- 0.04. The blood velocities in these vessels significantly declined with increasing age of subjects (P < 0.05). CDI is a noninvasive, accurate and reproducible modality for the study of ocular and orbital hemodynamics.