Assessment of microheterogeneity of blood flow in the rat urinary bladder by high-resolution digital radiography.

OBJECTIVES: To assess high-resolution digital radiography for measuring blood flow and thus examine the microheterogeneity of bladder microcirculation in a rat model. MATERIALS AND METHODS: Microheterogeneity of blood flow in both mucosa and detrusor muscle of eight anaesthetized rats was investigated using an imaging technique with very high spatial resolution (0.1 x 0.1 mm(2)) using digital radiography combined with the deposition of (3)H-labelled desmethylimipramine. The spatial pattern of blood flow was quantified by the coefficient of variation of the regional flow (CV = sd/mean). RESULTS Muscle blood flow was less than mucous blood flow (muscle : mucosa, 2.9 : 5) in the empty bladder. In the muscle layer the blood flow distribution was more heterogeneous than that in the mucosa, with a mean (sd) CV in muscle and mucosa of 0.33 (0.033) and 0.16 (0.019), respectively (P < 0.001) at the capillary level. CONCLUSION: There was a heterogeneous distribution of blood flow in the microcirculation to capillary vessels in the muscular layer, possibly reflecting a difference in dynamic blood flow of regional perfusion of the emptied bladder.