Objective To investigate the changes of microstructure and blood perfusion of thalamus and basal ganglia in patients with untreated depressive disorder using diffusion kurtosis imaging (DKI) and three-dimensional arterial spin labeling (3D ASL) perfusion imaging.Methods Totally 21 untreated patients with depressive disorder (disease group) and 32 healthy volunteers (control group) underwent DKI,3D ASL and routine MR scanning were enrolled.DKI parameters (mean kurtosis [MK],axial kurtosis [Ka],radial kurtosis [Kr],fractional anisotropy [FA],mean diffusivity [MD],axial diffusivity [Da] and radial diffusivity [Dr]) and 3D ASL parameters (cerebral blood flow [CBF]) of bilateral heads of caudate nucleus,thalamus and putamens were measured and compared between the 2 groups.Results Compared with control group,Ka of left caudate head in disease group was significantly higher,while Kr was significantly lower (both P＜ 0.05).Ka of right putamens in disease group was significantly higher than that in control group (P＜0.05).Compared with control group,CBF of left caudate head and bilateral putamens decreased significantly in disease group (all P＜0.05).Conclusion Untreated depressed patients show abnormal DKI parameters and blood perfusion in basal ganglia,which indicating that microstructure integrity is impaired and blood perfusion decreases.The abnormalities in basal ganglia microstructure and blood perfusion may serve as one of the neuroimaging features of depressive disorders.

Since 1950s,the idea of liver transplantation (LT) was proposed,the technique of LT had been gradually and widely applied in the field of surgery.The development of LT experienced three stages,including animal experiment,clinical probation and clinical application.It is well known that LT is the only effective therapeutic method for terminal stage of liver diseases.In liver transplantation,the ischemia-reperfusion injury is difficult to avoid,and an important factor causing poor liver function.Meanwhile,hemodynamic volatility and internal environment disorder are important prognostic factors.How to reduce ischemia-reperfusion injury of the transplanted liver and improve intraoperative hemodynamic changes in liver transplantation is a clinical research focus.Recent studies has indicated that orthotopic liver transplantation retrograde perfusion method can effectively reduce the transplanted liver ischemia-reperfusion injury and improve liver function early after transplantation,and thus significantly improve the success rate of liver transplantation and survival.

BACKGROUND:At present, col agen as a material in periodontal tissue engineering has some disadvantages such as poor mechanical strength and rapid degradation speed. Col agen combined with chitosan can improve above-mentioned problems.
OBJECTIVE:To evaluate the biocompatibility of a novel chitosan-col agen scaffold in vitro.
METHODS:Cytotoxicity of the extract of chitosan-col agen scaffold in different concentrations (100%, 75%, 50%, 25%) was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Human periodontal ligament cel s at 4-6 passages were cocultured with the chitosan-col agen scaffold. Cel growth on the scaffold was observed. Changes in alkaline phosphatase activity were detected in periodontal ligament cel s before and after coculture.
RESULTS AND CONCLUSION:The novel chitosan-col agen scaffold was made up of double layers with one dense layer and another loose layer. The grade of the cytotoxicity of the scaffold was from 0 to 1. Scanning electron microscope and histological observation demonstrated that cel s grew wel on the chitosan-col agen scaffold;the dense layer could prevent cel s to migrate into the scaffold. There were no significant differences in alkaline phosphatase activity in human periodontal ligament cel s before and 24 hours after combined culture (P>0.05). Alkaline phosphatase activity in human periodontal ligament cel s was greatly higher at 48 and 72 hours after combined culture compared with that before culture (P<0.05). Above results indicated that the novel chitosan-col agen scaffold has a good biocompatibility and barrier function, and potential as a scaffold for periodontal tissue engineering.

Objective To evaluate MR relaxometry techniques and dual-energy X-ray absorptiometry (DXA) for the diagnosis of osteoporotic diseases in rats. Methods Thirty 3-month-old female rats were randomly divided (using completely randomized grouping method) into two groups (each contained 15 rats). Animals in group A without osteoporotic castration were included as normal controls, whereas osteoporotic castration was created in each animal in group B. Three parameters (BMC, BMD, Hbmdl)was measured for both groups by DXA at two time points, one immediately before the castration and another at the 12 th week after the castration. Then animals from the control group and the osteoporotic group went through the following three diagnostic procedures using a 1.5 T MR system: (1) A fast multi echo gradient echo (MEGRE) pulse train sequence with different inter-echo intervals (1000, 500, 400, 300, 200, 100) to obtain the T_2~* value. (2) A multi-echo fast spin echo sequence to obtain the T_2map. (3) A conventional spin-echo (CSE) sequence to obtain the T_1map. The statistical difference between group A and group B was tested by t-test to analyze parameters. And, the most significant parameter for diagnosis ofosteoporotic diseases was picked out from all parameters by Fisher Sequential diseriminant analysis. At the end of experiments, animals were killed and histopathological examination was performed on the femurs of animals from both control and osteoporotic groups. Results (1) Histopathological examination confirmed the presence of osteoperosis in all animals in group B. (2) BMD was picked out from 3 DXA parameters (BMC,BMD,Hbmdl) by fisher stepwise discriminant analysis, and its discriminant rates was 87.6%. (3) All 2-sample t-test results(t=6.20, 4.79, 5.18, 5.22, 5.59, 4.37, 6.14, 5.12, 5.09, 4.99, 5.57, 4.84, 4.07, 2.98, 6.75 individually) for MR relaxometry parameters(T_2~* 1000,R_2~* 1000,T_2~* 500,R-2~* 500,T_2~* 400,R_2~* 400,T_2~* 300,R_2~* 300,T_2~* 200, R_2~* 200, T_2~* 100, R_2~* 100, T_2map, R_2map, T_1map) showed statistically significant differences between groups A and B (P=0.01 for T_2~* map, P=0.00 for all other parameters) except the R_2map(P=0.07). (4) Using fisher stepwise discriminafion method in the analysis of 14 parameters of MR relaxometry techniques and 3 parameters of dual X-ray absorptiometry(T_2~* 1000,T_2~* 500,T_2~* 400,T_2~* 300,T_2~* 200,T_2~* 100,T_2map, R_2~* 1000, R_2~* 500, R_2~* 400, R_2~* 300, R_2~* 2OO, R_2~* 100,T_1map,BMC,BMD,Hbmdl), we found that the most significant difference was from the T_2map and T_1map. Conclusions The MR relaxometry parameter-T_2map in the present study is shown to be appropriate parameter for the diagnosis of osteoperotie diseases, and stability of magnetic field plays an important role in this process. It would be the optimal method to make a diagnosis of osteoporotic diseases with both MR relaxometry and DXA technological means.

Objective To study the value of diffusion tensor imaging(DTI) in early assessment of prognosis of hypoxic-ischemicencephalopathy(HIE) in new infants. Methods 96 cases of full term infants with HIE underwent DTI examinations at 0～12 days and 6～36 months. Based on clinical diagnostic criteria, 96 cases were divided into three groups: mild, moderate and severe HIE groups. Fractional anisotropy(FA) values in the corpus callosum splenium and the posterior limb of internal capsules were measured. Results (1) Varying degrees of FA groups was significantly different from the same site, increased linearly with time,but the magni-tude of change was different;(2)When FA value of corpus callosum splenium in the cut-off point was ≥0.437,the sensitivity(SE) was 83.8% , the specificity(SP) was 18.6% , ROC area under the curve was 0.903 , 95% confidence interval was from 0.846 to 0.961,standard error was 0.029;when FA value of posterior limb of internal capsule in the cut-off point ≥0.391,SE was 86.5%, SP was 11.9% ,ROC area under the curve was 0.940,95% confidence interval was from 0.898 to 0.984,standard error was 0.022. Conclusion MR DTI examination is of significant value in evaluating early the prognosis of HIE in infants.

0.05). Conclusions DTI is valuable in assessing the directionality and density of white matter and can reflect the age-related physiological changes of white matter in vivo non- invasively.

Objective To compare with the advantage or shortage of several scan series in imaging of normal articular cartilage in knee.The MR manifestation were observed and thickness of different location of cartilage in knee in different series were calulated.Methods The knees of 30 healthy volunteers were imaged with five different MR imaging sequences including T 1-weighted,proton density-weighted,T 2-weighted FSE,STIR and 3D-FS-SPGR.The value of CNR were determined for cartilage versus a saline fluid phantom,marrow fat,and muscle.The MR 2D and 3D manifestation were observed and thickness of different location of cartilage in knee in different series were calculated.Results The value of CNR of 3D-FS-SPGR for cartilage versus a saline fluid phantom,marrow fat,and muscle were compared with other sequences and were significantly different.The values of cartilage thickness with 3D-FS-SPGR were more than those with other series.The mulplaner appearance was observed.There was five-plane manifestation when cartilage thickness was more than 4 mm.The value of cartilage thickness of male and female were 2.63 mm and 2.52 mm,respectively.Conclusion 3D-FS-SPGR sequences have significant advantage compared with other series in imaging normal articular cartilage of knee.The cartilage is show clearly than other sequences.The value of cartilage thickness with 3D-FS-SPGR is more accurate.Moreover it can also provide much information adding to 3D construction of cartilage.

Objective To study the roles of isotropic diffusion weighted imaging and apparent diffusion coefficients (ADC) mapping in diagnosing cerebral infarction, monitoring the development of cerebral infarction and defining the infarction stages.Methods 86 work-ups in 70 patients with cerebral infarction (8 hyperacute, 13 acute, 32 subacute, 11 steady, and 22 chronic) were imaged with both conventional MRI and single-shot echo-planar isotropic diffusion weighted imaging.The change of the infarct lesion in DWI and T_2WI was also analyzed.The average ADC, relative ADC (rADC), and the ADC from center to periphery of the lesion were calculated.Results 8 hyperacute cerebral ischemic regions were revealed at DWI and ADC mapping.Hyperacute and acute infarcts appeared as areas of hyperintensity on DWI, and their average ADC was significantly depressed compared with that of homologous contralateral tissue [(0.698?0.104) ?10 -3 mm 2/s versus (0.990?0.161)?10 -3 mm 2/s; t=-14.372, P

Objective To study the value of MR perfusion-weighted imaging(PWI)after administration of acetazolamide(ACZ)in evaluating the cerebrovascular capacity.Methods MR perfusion-weighted imaging were performed before and after ACZ administeredorally in 7 cases with cerebral infarction.The values of rCBV and rMTT were analysed and the cerebrovascular capacity were evaluated.Results The prolonged rMTT was found in rMTT map before and after ACZ in all cases.Only 5 subjects were abnormal at rCBV map visually.rMTT was increased at the abnormal region on rMTT map.The abnormal regions at rCBV maps included both rCBV increased or decreased.The abnormal region was larger at rMTT map than that at rCBV map.Conclusion MR perfusion-weighted imaging with ACZ test has significant value in assessing the cerebrovascular capacity.

Objective:To eveluate and study the anatomic basis of the posterior contour sign of lumbar intervertebral disc.Methods:The most protruding length of the soft tissue mass behind intervertebral spase on lumbar plain film were measured in 100 cases and compared with CT or MR findings.Results:41 posterior contour sign of the interlumbar disc were fined in 39 cases,of which there were 25 in L4/5(61.0%),15 in L3/4(15.6%)and 1 in L2/3(2.4%).The protruding was less than 0.2 cm in 26 and larger than 0.2 cm in 15,there were 10 lumbar disc protruding confirmed by CT or MR ,7 of which the pesterior contour ≥0.2 cm,and 3＞0.3 cm,none was ≤0.2 cm.Conclusion:The adipose tissue in the posterior border of lumbar body and disc was the anatomic basis of the sign,and it was an importent sign for diagnosing of lumbar disc hernia on plain film.