Hemodynamic changes vs pathologic foundation in rabbit models of radiation-induced lung injury: a preliminary study / 中华放射学杂志

ABSTRACT

Objective To study the hemodynamic changes and pathologic foundation of rabbit models of radiation-induced lung injury (RILI) via 64-slice CT pulmonary perfusion imaging ( CTPI),in order to seek the correlation between the alterations of the hemodynamic parameters and pathophysiology.Methods Seventy-two healthy New Zealand rabbits were randomly classified into two groupstest group ( n =36),received 25 Gy with single fraction irradiation in a whole unilateral lung; control group ( n =36),received sham-irradiation.Each group was divided into 12 subgroups respectively according to post- and pseudo-irradiation time points (1,6,12,24,48,72 h and 1,2,4,8,16,24 w).Each rabbit underwent HRCT and CTPI at every pre- and post-radiation time point.All rabbits were sacrificed,and morphology of specimens was observed using light- and electron microscope. The changing regularity of HRCT,CTPI parameters and pathology were analyzed and compared with each other in order to find the correlation among them.The CTPI parameters of the test and control groups were compared using t test.The CTPI parameters and pathological values were analyzed using linear correlation with two variables,the detection rates of RILI by CTPI and HRCT was compared using Chi-square test.Results ( 1 ) The changes of CTPI parameters from control group after irradiation was relatively stable,but in test group those parameters including rBF,rBV and rPS,at pre- and post-irradiation time points (0,72 h and 2 w),were respectively 1.01 ± 0.09,1.86 ± 0.20,1.43 ±0.12,1.03 ±0.08,1.63 ±0.19,1.56±0.14,0.96±0.12,1.54 ±0.17 and 1.83 ±0.24.The corresponding parameters before and after irradiation were significantly different ( t =2.90-6.37,P ＞ 0.05).(2)In test group,capillary endothelial cells,basement membrane and alveolar epithelial cells,as the main injury targets,showed certain alterations in pathology.There was a significant correlation between the changes of CTPI parameters ( rBF and rBV) and pathophysiology in control group ( r =0.74,0.83,P ＜0.05 ),with the dependent relationship between rPS and the amounts of RBC outside the capillary and the destruction of basement membrane( r =0.87,0.88,P ＜ 0.01 ).(3)The detection rate of RILI with CTPI (72.2％,26/36) was obviously higher than that with HRCT( 16.7％,6/36,x2 =4.37,P =0.036).Conclusions CTPI parameters is capable of revealing the rule of hemodynamic process and reflecting the pathophysiologic state of different stages of RILI.By the time of detecting RILI,the detection rate of CTPI is clearly superior to that of HRCT,which yields potential value in predicting RILL