Errors in bone blood flow measured with microspheres due to sample preparation technique

Regional blood flow and strontium-85 incorporation rate in the rat hindlimb skeleton

Regional distribution of radioactive microspheres and 85Sr incorporation rate in the os ilium, femur, and tibia were determined in 44 rats. In 15 additional animals, regional blood flow was measured with the reference sample technique. Highest numbers of microspheres were found in the distal femoral and proximal tibial metaphyses. Highest blood flow rates were found in the os ilium, the caput femoris, and distal femoral and proximal tibial metaphyses. The diaphyses and epiphyses of the femur and tibia had a relatively lower perfusion. The regional 85Sr incorporation rate was correlated (r = 0.67) to the regional distribution of the microspheres. The dispersion of the data was large and this was mainly due to biological variation. The results describe the regional distribution of blood flow in the rat hindlimb and demonstrate a close association between blood flow and mineral turnover in normal rat skeletal tissue as shown by the correlation between microsphere and 85Sr incorporation rate distribution.