BACKGROUND: Animal models of peripheral partial epiphyseal plate closure are commonly used in related trials.OBJECTIVE: To modify the original animal models of distal femoral partial epiphyseal plate closure.DESIGN, TIME AND SETTING: A self-controlled trial was performed at the Experimental Animal Center of General Hospital of Chinese PLA from March to October 2007.MATERIALS: Twenty healthy New Zealand rabbits of 4-6 weeks old weighing 1.0-1.5 kg were selected.METHODS: A straight incision about 2 cm was made in lateral knee of 20 rabbits. The subcutaneous tissues and knee capsule were cut open to expose distal femoral condyle. The condylar plate line was clear. Two holes were drilled in the fight lateral condyle, about 3.0-4.0 mm deep, and partial normal epiphyseal plate (about 33%-44% of the total growth plate) was removed. An incision deep to periosteum was created in the left side and regarded as self-control.MAIN OUTCOME MEASURES: Femoral length, valgus angle of the distal femur, and femoral deformity were detected by X-ray photograph, and gross observation. Bone bridge formation of bilateral femora was observed by histological examination.RESULTS: One rabbit died of diarrhea 31 days after surgery, and 19 were included in final analysis. ①Radiographs showed that the mean length of left femur (control side) was significantly longer but valgus angle was significantly smaller than the right side (experimental side) 4 months after surgery (P ＜ 0.01). The left distal femur averagely grew for 2.27 cm,accounted for 57.6% of the overall femoral growth, and the right side averagely grew for 0.45 cm, accounted for 21.4% of the overall femoral growth.②Four months after surgery, femoral appearance of the control side was normal, with smooth and complete condylar and facies articularis patellae. While, the experimental side femur was significantly shortened, and severe vaigus deformity was observed in the distal femur. ③Five weeks after surgery, layer cells of the epiphyseal plate arranged regularly in the control side. Bone trabecula with many fibers was found in bone defect cavity of the experimental side, and the cell layer of the remnant epiphyseal plate was decreased. The epiphyseal plate was closed in the control side,and bone trabecula of the experimental side was thickened 10 weeks postoperatively.CONCLUSION: This modeling method is simple, efficient, and easy to manipulate; in addition, the bone bridge area is controllable. The models can meet the study demands for peripheral partial epiphyseal plate closure, and are significant for filling material selection during treatment.

Objective To explore clinical significance of muhidetector(64-row)computed tomography carotid atherosclerosis angiography(MDCTA)in detecting carotid atherosclerotic plaque.Methods Data of 116 patients with carotid atherosclerosis undergone with MDCTA stayed at Huashan Hospital,Shanghai from January to August,2008 were analyzed retrospectively.Results Three hundred and seventy-seven plaques were identified among all the 116 patients in the study,with an incidence of calcified plaque of 63.40 percent,and more detected at the common carotid artery(27.85%).the carotid bifurcation(39.78%)and the internal carotid artery (21.48%).There was significantly statistical difference in plaque types between those with mild,moderate and severe carotid stenosis(P=0.000)and between those aged equal to or lower than 50 years and equal to or greater than 70 years(P=0.005).Plaque types at the common carotid artery were significantly difierent from those at the carotid bifurcation(P=0.000)and at the internal carotid artery(P=0.000).Results of regression analysis showed a positive and significant association between carotid occlusion and clinical symptomatology(with a coefficient of correlation of 1.080.P=0.023)and inverse association between calcified plaque and clinical symptomatology(with a coefficient of correlation of 0.688,P=0.006).Conclusions Not only imaging characteristics of carotid atherosclerotic plaque can be accurately assessed by MDCTA,but also measurement of its stenosis degree.Assessment of plaque type,degree of stenosis and distribution of plaque in different Vascular segments with MDCTA can be used to predict clinical occurrence of cerebevaseular events in patients with carotid atherosclerosis.

Objective To assess the effect of iDose4 in image quality and radiation dosage in CT angiography of craniocervical arteries.Methods Imaging data of 50 patients with 256-slice spiral CT angiography of craniocervical arteries were randomly divided into two groups:(A) 120 kV,250 mAs (25 patients),(B) iDose4 100 kV,180 mAs (25 patients).Dose length product (DLP) of the two groups were compared.Objective image noise was compared by two blinded readers,t test and nonparametric tests were used for statistical analysis.Results The overall image quality score of group A (3 points =1 patient,4 points =6 patients and 5 points =18 patients) and group B (4 points =5 patients and 5 points =20 patients) were shown.The image noise of group A (1 point =1 patient,2 points =5 patients and3 points =19 patients) and group B (2 points =4 patients,3 points =21 patients) were also evaluated.There was no statistical difference in revealing rate of image quality scores and objective noise between the two groups (Z =-0.334,-0.218,P ＞ 0.05).The estimated effective radiation dose was reduced by 56％ in group B than in group A.DLP was significantly lower in group B [(642.4 ±36.6) mGy · cm]than in group A [(1462.1 ± 64.3) mGy · cm].Conclusion Low dose contrast medium of CT angiography can display craniocervical arteries and the intracranial arteries very well with high image quality.