Objective:To compare 2DMRCP and 3DMRCP and It’s clinical application.Methods:Eighty patients underwent 2D and 3D MRCP with 3.0T MR.Routine axial and coronal spin echo pulse sequence were performed at the same time.The ability of these two different techniques to depict the bile duct and pancreatic duct were compared.Results:Gallblader,cystic duct,three grade hepatic duct and common bile duct were shown both in 2D and in 3D MRCP 100%.4th grade hepatic duct 92.5%,5th grade hepatic duct 77.5%,pancreatic duct 90% and accessory pancreatic duct 11.25% were shown in 2D MRCP while the corresponding display rate were 85%,70%,87.5% and 6.25% respectively in 3D MRCP.Conclusion:Breath-hold 2D MRCP and breath-control 3D MRCP in 3.0T is an efficient technique to depict biliary system and pancreatic duct.Combining 2D with 3D MRCP will improve the ability display of bile duct and pancreatic duct.

BACKGROUND:Tissue-engineered intervertebral disc has provided a new biological therapeutic approach for intervertebral disc degeneration. Tissue-engineered annulus fibrosus is one key step of constructing a complete tissue-engineered intervertebral disc. OBJECTIVE:To sum up the research progress of tissue-engineered annulus fibrosus from the folowing aspects: structural features, scaffold materials, seed cels. METHODS:PubMed database and Wanfang database (2000-2015) were retrieved by the key words of “tissue engineering, intervertebral disc, annulus fibrosus, seed cel, scaffold, construction” in Chinese and in English, respectively. According to inclusion and exclusion criteria, 48 literatures were involved for summarization. RESULTS AND CONCLUSION: Previous studies about tissue-engineered annulus fibrosus only focused on cel adhesion, proliferation and extracelular matrix secretion on the scaffold. Currently, tissue-engineered annulus fibrosus exhibit similar features to the natural annulus fibrosus in the folowing aspects: cel function, tissue structure and mechanical features, and relevant animal experiments have achieved certain results in animal experiments. However, it is stil difficult to build a tissue-engineered annulus fibrosus entirely similar to the natural one, and we need to further improve scaffold materials, culture conditions, colection of seed cels. The current strategies of annulus fibrosus construction stil focus on single phase of scaffold, and the biphasic scaffold and complete intervertebral disc scaffold wil be the trend of the researches. Technology of induced differentiation of stem cels provides a broach source of seed cels for tissue-engineered annulus fibrosus.

Objective To investigate the best digestion time for rabbit rib cartilage cells separation by collagenase Ⅱ diges‐tion method .Methods Rabbit cartilage tissue was taken from 3‐month‐old New Zealand white rabbits ,and then digested in 0 .2%collagenase Ⅱ solution for 4 ,8 ,12 ,16 and 20 h under vibration at 37 ℃ ,respectively .The corresponding experiments were named as group A ,B ,C ,D ,and E .The obtained primary cells were cultured and passaged after counting .The cell morphology ,proliferation rate ,secretion of extracellular matrix of passage 2 cells were compared to chose the best digestion time .Results The primary chon‐drocytes obtained in group C ,D and E were more than the other two group A and B .The chondrocytes cytoactive in group C and D were better than the other three group A ,B and E .The passage 2 chondrocytes in group C ,D had better secretion of extracellular matrix capability than the other three groups .Conclusion The best collagenase Ⅱ digestion time is 12 to 16 h ,at this digestion time period ,more primary chondrocytes with high cytoactive and strong proliferation capability can be obtained ,and the phenotype of their passage 2 cells is quite good .

Objective To construct a novel tissue?engineered bone matrix gelatin (BMG)/poly[butylene succinate?co?tere?phthalate] (PBST) biphasic scaffold for annulus fibrosus. Methods The PBST spinning fibers were prepared by electrospinning and the porosity and water absorption rate were tested. Rabbit annulus fibrosus cells were isolated, cultured and identified through SafraninOstaining, and collagenⅡimmunohistochemical staining in vitro. And then annulus fibrosus cells were implanted on the PBST fiber, whose growth situation was observed by scanning electron microscope (SEM). Then the BMG/PBST biphasic scaf?fold was constructed by BMG as the outer annular fibrosus and PBST fiber as the inner annular fibrosus. The annulus fibrosus cells were implanted on the biphasic scafflod and cultured for 3, 7 and 21 days in vitro. The biomechanical and biological property was observed at the predetermined time point. Results The porosity of the fiber was 61.83%±7.33%and its water absorption rate was 297.34%± 57.13%. The identified result of annulus fibrosus cells were positive, suggesting that the cells have still kept their annulus fibrosus cells characteristics. The cells growth could be observed through SEM at 3rd and 7th day after implanted on the fi?bers. After cultured on the BMG/PBST scaffold, HE staining proved that the cells could ingress into the inner of fiber with time. SafraninOstaining and collagenⅡimmunohistochemical staining proved that the cells can secreted abundant proteoglycan and collagenⅡ, the special annulus fibrosus cell extracellular matrix. Compared with the BMG/PBST scaffold without cells, the elastic modulus of biphasic scaffold was increased from 14.83±1.02 MPa to 17.56±1.47 MPa after cultured with cells for 21 days in vitro. Conclusion The novel tissue?engineered biphasic scaffold for annulus fibrosus constructed with BMG and PBST fiber spinning has good cytocompatibility and biomechanical characteristics, which provide a basis for the complete tissue engineered interverte?bral disc.

Objective To fabricate a novel tissue-engineered cartilage with adipose-derived stem cells (ADSCs) seeded on the chitosan hydrogel scaffold to repair articular cartilage defect.Methods Adipose tissue and costal cartilage were harvested from New Zealand rabbits,and ADSCs in passage one and chondrocytes were obtained after the samples were digested and cultured in vitro.ADSCs were digested,suspended,seeded onto the sterile chitosan gel,and cultured in vitro for 1 week to fabricate the tissue-engineered cartilage.The defects were respectively filled with the tissue-engineered cartilage (composite group),chondrocyte suspension (cell group),chitosan gel (material group) and nothing at all (control group).At postoperative 12 weeks,cartilage repair was evaluated using the gross examination,histological staining,immunohistochemical staining and international cartilage repair society (ICRS) histological score.Results Effect of cartilage repair in composite group was significantly better compared to other groups.The regenerated tissue in composite group seemed tightly bound in normal tissue,with similar structure and extracellular matrix secretion.ICRS histological score in composite group was (13.89 ± 0.14) points,which differed significantly from (7.06 ± 0.19) points in control group,(7.14 ± 0.22) points in cell group and (7.46 ± 0.26) points in material group (P ＜0.01).Conclusion The tissue-engineered cartilage with ADSCs seeded onto the chitosan hydrogel is effective for repair of articular cartilage defect.

Objective To observe the MR findings of myxoid-round cell liposarcoma of the lower extremities and to evaluate therelationship between MR findings and pathologic features. Methods MR findings of 6 myxoid-round cell liposarcomas of the lowerextremities confirmed pathologically were retrospectively reviewed,including tumor's location,size,morphology,internal architecture and signal intensity characteristics on T_1WI,T_2WI and SPIR T_2WI and the pattern of enhancement.Results All tumors were located in thedeep space among skeletal muscles of the lower extremities,with unregular shape,sharp borber and thick septal structures.Tumors werehomogeneous or heterogeneous isointense on T_1WI and hyperintense on T_2WI relative to the signal intensity of skeletal muscles and heterogeneous enhancement after the injection of GdDTPA.Conclusion MRI may lead to a correct diagnosis of myxoidround cell liposarcoma of the lower extremities.

Objective To detect the meshwork of tiny lymphatic channels at bilateral vertebral body and ventral aorta at 3.0 Tesla and to probe the relationship between its detective ratio and some diseases.Methods Fat-suppressed T2-weighted imaging in 91 patients was performed at the upper abdomen. The meshworks of tiny lymphatic channels at bilateral vertebral body and ventral aorta on contiguous axial and coronal images were reviewed. The classifications of the lymphatic meshwork were made according to its width and length on coronal images. The differences in the detective ratios of the lymphatic meshwork between control group and the risk ones including portal hypertension group, choledochus obstruction group and malignant tumour group were analyzed.Results Right- or left-sided lymphatic meshwork at vertebral body or ventral aorta were 34.07%(31/91),32.97%(30/91),32.97%(30/91) and 43.96%(40/91) respectively. The detective ratio of the lymphatic meshwork on the side of the ventral aorta was higher significantly in the portal hypertension group than that in the control or malignant tumour one (P0.05). Conclusion Meshwork of tiny lymphatic channels at bilateral vertebral body and ventral aorta allows to be detected on fat-suppressed T2-weighted imaging at 3.0 Tesla, and the portal hypertension may influence the detective ratio of the lymphatic meshwork on the side of the ventral aorta.