[Quantitative study of therapeutic efficacy on early intervention of hyperbaric oxygen to model of steroid-induced avascular osteonecrosis of femoral head by multi-slice perfusion imaging].

OBJECTIVE: To quantitatively evaluate the hemodynamic status in animal models of steroid-induced avascular osteonecrosis of femoral head (SANFH) by multislice CT (MSCT) perfusion imaging, and estimate the therapeutic efficacy on early intervention of hyperbaric oxygen (HBO) to improve the region blood flow (rBF) of ischemic femoral head.

METHODS: Forty-eight New Zealand male rabbits were injected with Escherichia coli endotoxin and methyl-prednisolone to establish SANFH models and then divided into 3 subgroups to undergo MSCT to measure the rBF, regional blood volume (rBV), and mean transit time (MTT) to obtain perfusion maps at the femoral head epiphysis, metaphysic, and neck of femur, and then were killed to undergo histological examination of the bilateral femoral heads 2, 4, and 6 weeks later respectively (Groups M(2), M(4), and M(6)). Twenty-four rabbits underwent HOB treatment after the second injection of E. c. endotoxin for 1-3 courses respectively (Groups H(1), H(2), and H(3)), and then underwent MSCT and pathological examination as described above. Eight rabbits were used as controls (Group N).

RESULTS: (1) The rBF values of Groups M(2), M(4), and M(6) were all significantly lower than that of Group N (P < 0.001, < 0.001, and < 0.002). The rBF value of femoral head epiphysis of Group M(2) was remarkably lower than that of Group N, decreased to the lowest in Group M(4), and re-increased in Group M(6). The rBV value demonstrated similar change pattern in femoral head epiphysis. The MTT values of Groups M(2) and M(4) were longer than that of Group N, and then re-decreased in Group M(6). (2) It did differ significantly between the perfusion data of different femoral head anatomic regions in Groups M(2), M(4), M(6) and N (rBF: F = 52.190, P < 0.001; rBV: F = 42.677, P < 0.001; MTT: F = 3.09, P = 0.048). The changes of the perfusion data in femoral head epiphysis were more significant than those in other anatomic regions. (3) There were no statistically significant differences in the rBF value of the femoral head epiphysis and metaphysis (F = 2.081, P = 0.115; F = 1.142, P = 0.341), in the rBV value of the femoral metaphysis and neck of femur (F = 2.642, P = 0.059; F = 1.568, P = 0.209), and the MTT value of all the anatomic regions (F = 1.111, P = 0.347) among Groups H(1), H(2), H(3), and N. The rBF values of Groups H(1), H(2), and H(3) were statistically higher than those of the corresponding phase model groups (all P < 0.05).

CONCLUSIONS: Able to detect hemodynamic status of femoral head, MSCT perfusion imaging technique may be used in the early detection of SANFH. Early intervention of HBO therapy can improve the blood perfusion of femoral head.