Comparison of regional blood flow values measured by radioactive and fluorescent microspheres

Fluorescent microspheres (FM) have become an attractive alternative
to radioactive microspheres (RM) for the measurement of regional
blood flow (RBF). The aim of the present study was to investigate
the comparability of both methods by measuring RBF with FM and RM.
Eight anaesthetised pigs received simultaneous, left atrial
injections of FM and RM with a diameter of 15 mum at six different
time points. Blood reference samples were collected from the
descending aorta. RBF was determined in tissue samples of the
myocardium, spleen and kidneys of all 8 animals. After
radioactivity of the tissue samples was determined, the samples
were processed automatically for measuring fluorescence using a
recently developed filter device (SPU). RBF was calculated with
both the isotope and spectrometric data of both methods for each
sample resulting in a total of 10,512 blood flow values. The
comparison of the RBF values yielded high linear correlation (mean
r(2) = 0.95 +/- 0.03 to 0.97 +/- 0.02) and excellent agreement
(bias 5.4-6.7%, precision 9.9-16.5%) of both methods. Our results
indicate the validity of MS and of the automated tissue processing
technique by means of the SPU. Copyright (C) 2002 S. Karger AG,
Basel.