A minimally invasive technique for multiple measurement of regional blood flow of the rat brain using radiolabeled microspheres.

To observe the rat brain blood flow with microspheres, a left ventricular catheter for sphere introduction was threaded into position via the right brachial artery. Cross-circulation with a donor rat was employed to prevent any mismatch between the infused and sampled blood volumes. Multiple measurements yielded stable flow data, and the responsiveness to hypercapnia was well preserved, irrespective of the dose of injected spheres (48 x 10(3) and 130 x 10(3)).