MR line-scan diffusion imaging in ischemic epiphysis of femoral head:preliminary experimental study in piglets / 中华放射学杂志

ABSTRACT

Objective To observe diffusion changes of epiphysis of femoral head with ischemia of difference phases by line-scan diffusion weighted imaging(LSDWI),and determine whether LSDWI can provide temporal information and severity about ischemia of epiphysis.Methods lschemia was surgically induced in one hip of each piglet(n=25)and the other hip served as a normal control.Piglets were imaged before surgery and at 3 hours,72 hours and 1,3 and 6 weeks after surgery by using LSDWI.Apparent difrusion coefficients(A DC)in epiphysis of the femoral heads were calculated.Significant difierences in ADC values between ischemia group and control group were found by using paired t-test.After scan at individual time points,5 piglets were sacrificed for histological study each time.Results The ADC value in the ischemic femoral heads f(1.22±0.37)×10-3 mm2/s]decreased significantiy at 3 hours after surgery (t=3.914,P＜0.01),compared to that in control[(1.73±0.33)×10-3mm2/s},and increased at 72 hours[(2.15±0.32)×10-3mm2/s versus(1.70±0.22)×10-3 mm2/s](t=3.348,P＜0.01).Then ADC valne kept increasing until 6 weeks after surgery[(1.61±0.27)×10-3mm2/s in ischemia side vs (1.11±0.45)×10-3mm2/s in the control](t=4.136,P＜0.01).rrhe percentage change of the ADC value significandy increased at 3 hours,72 hours,1 and 3 week(s)after the surgery(P＜0.01),compared to that at the prior neighboring time point.No significant increase in the percentage change of ADC value was found between the 3rd week and the 6th week after the surgery(t=2.29.P＞0.05).Histological examinations revealed abnormal thickening within epiphyseal cartilage,and cartilaginous islands within ossified tissues.Growth disturbante wag found in form of focal growth plate disruption.Conclusions Dynamic changes of ADC values were found with the prolonged ischemia of the femoral head by LSDWI.It could serve as a useful marker for evaluating duration and extent of ischemic epiphyseal disruption.