Cochlear Blood Flow in the Rat: A Comparison of 10- and 15- m Spheres

Abstract
• The microsphere method combined with surface preparation dissection is described for measuring cochlear blood flow in the rat. Two sphere sizes, 10 and 15 μm, were compared. No difference between the two sizes was found for measuring total cochlear blood flow. Shunting of the 10-μm spheres appeared to be similar to shunting of the 15-μm spheres and thus was minimal. However, the 15-μm spheres distributed poorly to the apical cochlea, especially the spiral portion. The 10-μm sphere was less toxic, allowing larger numbers of spheres to be infused. Consequently, more 10-μm spheres lodged in the cochlea, which is important for reducing random error. For these reasons, we recommend the 10-μm sphere, as opposed to the 15-μm sphere, for studying cochlear blood flow in the rat. (Arch Otolaryngol Head Neck Surg 1986;112:180-185)