Objective To study the value of three dimensional contrast enhanced subtraction MRA (3D CES MRA) in the diagnosis of extremity musculoskeletal diseases. Methods Fifteen cases of extremity musculoskeletal diseases proved by operation and pathology were studied, including upper extremity ( n =5), lower extremity ( n =10), soft tissue and vascular lesions ( n =8), and skeletal lesions ( n =7). All examinations were performed with GE 1.5 T MRI scanner. Sagittal scout images were obtained by 2D FMPSPGR sequences. Before and after contrast enhancement, coronal 3D FSPGR sequence was performed in the same parameters within 32 seconds. The plain source images were subtracted by enhanced source images in the workstation. The subtracted images were processed by MIP technique, such method is so called 3D CES MRA. Results All lesions were demonstrated accurately by 3D CES MRA, including vascular lesions ( n =6), tumors in the soft tissue ( n =3), benign skeletal tumors ( n =1), and malignant skeletal tumors ( n =3). Compared with pathology, the diagnosing accuracy rate of 3D CES MRA was more than 90%. Conclusion 3D CES MRA is an advanced, safe, and noninvasive method in diagnosing extremity musculoskeletal diseases, further more, it can save time and resources. In general, 3D CES MRA has a great value in clinical application.

An experimental animal model of malignant soft-tissue tumor was established to investigate the applied value of multi-slice spiral CT perfusion imaging preliminarily. Ten New Zealand white rabbits which were implanted with VX2 tumor in either proximal thigh were subjected to CT plain scan and perfusion scan two weeks later respectively, then the original perfusion images were transmitted to AW4.0 Workstation. The functional maps and perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were computed and analyzed. All the values of BF, BV and PS in VX2 soft-tissue tumors were obviously higher while the MTT-values were lower than those in the normal muscular tissues significantly. It was suggested that multi-slice spiral CT perfusion imaging is an accurate, convenient and relatively safe functional imaging technique, and can give a quantitative assessment to angiogenesis and blood perfusion of soft-tissue tumors.

To investigate the value of the guidance of three dimensional (3-D) reconstruction of multi-slice spiral CT (MSCT) for the placement of pedicle screws, the 3-D anatomical data of the thoracic pedicles were measured by MSCT in two embalmed human cadaveric thoracic pedicles spines (T1-T10) to guide the insertion of pedicle screws. After pulling the screws out, the pathways were filled with contrast media. The PW, PH, TSA and SSA of developed pathways were measured on the CT images and they were also measured on the real objects by caliper and goniometer. Analysis of variance demonstrated that the difference between the CT scans and real objects had no statistical significance (P > 0.05). Moreover, the difference between pedicle axis and developed pathway also had no statistical significance (P > 0.05). The data obtained from 3-D reconstruction of MSCT demonstrated that individualized standards, are not only accurate but also helpful for the successful placement of pedicle screws.

BACKGROUND: Traditional solid bone can not receive satisfied effects in repairing irregular bone defects in oral maxillofacial surgery due to uneven distribution of cells and growth factors. Therefore, it is a research direction to prepare injectable tissue engineering bone.OBJECTIVE: To explore the effects of chitosan/β-tricalcium phosphate/recombinant human bone morphogenetic protein-2(CS/β-TCP/rhBMP-2) composite on mandibular defect repair.DESIGN, TIME AND SETTING: A randomized controlled animal experiment. The experiment was performed atthe animal laboratory, Medical College of Jinnan University from May 2008 to March 2009.MATERIALS: The injectable tissue engineering bone was prepared by using complex of liquid CS and solid β-TCP as scaffold materials, and combined with freeze-dried rhBMP-2.METHODS: Twenty-four New Zealand white rabbits were prepared for double sides mandibular defect models, and randomized into 4 groups: ①CS/p-TCP/rhBMP-2 group: 1 mL CS/β-TCP/rhBMP-2 complex was injected into the defects.②CS/β-TCP group:0.5 mL CS/β-TCP complex was injected into defects. ③Autograft bone group: repairing the defects with sclerotin of the iliac crest.④Blank control group: no implantation. MAIN OUTCOME MEASURES: At weeks 2, 4 and 8 after surgery, the material degradation and new bone formation were evaluated with, haematoxylin-eosin staining, and electron microscope; the bone mineral density was detected by dual energy X-ray absorptiometry (DXA) to determine bone formation rate and quality.RESULTS: ①Gross observation demonstrated that the size and thickness of osteotylus in CS/β-TCP/rhBMP-2 group was equivalent with the autograft group, which were greater than that of the other groups.②Histologicalobservation demonstrated that there were more bone matrixes in the CS/β-TCP/rhBMP-2 group and autograft group than that in the CS/β-TCP group and blank control group at each time points. ③Scanning electron microscope image suggested that at 8 weeks after operation, the bone bed and the materials in CS/β-TCP/rhBMP-2 group were connected with bone, and the gap was diminished. The degradation of the materials was so obvious that the complete structure of materials could not be found. ⑤DXA detection appealed that the bone density of each group was gradually increased with time prolonged. The quantities of bone density in CS/β-TCP/rhBMP-2 group in weeks 2, 4 and 8 were significantly higher than CS/β-TCP group and blankcontrol group (P < 0.05).CONCLUSION: ①CS/β-TCP/rhBMP-2 has good biocompatibility, degradability and the capacity of bone guidance and bone induction. ②CS/β-TCP can be served as a promising carrier for BMP-2, which is a potential degradable biological material for repairing bone defects.

The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.
Epiphyses/*anatomy & histology ; Femur/anatomy & histology ; Femur/*growth & development ; Gadolinium/*diagnostic use ; Growth Plate/*anatomy & histology ; Growth Plate/blood supply ; Growth Plate/growth & development ; Image Enhancement ; Magnetic Resonance Imaging ; Swine ; Swine, Miniature

To analyze MR manifestations of postoperative spinal complications and investigate the value of MRI in the diagnosis and differentiated diagnosis, 114 cases of spinal postoperative complications were analyzed retrospectively and compared with the clinical data. The results showed that the main postoperative spinal complications included spinal stenosis (n=33, consisting of 21 cases of epidural fibrosis and 12 cases of epidural hematoma or epidural abscess), lack of spinal stability (n=43), infection (n=23, consisting of 7 cases of para-spinal soft-tissue infection, 5 cases of vertebral discitis, 4 cases of vertebral and appendix infection, 3 cases of epidural abscess, 2 cases of myelitis, 2 cases of spinal arachnoiditis), others (n=28, consisting of 12 cases of inner fixation failure, 9 cases of epidural hematoma, 7 cases of cerebrospinal fluid gusher). It is concluded that MRI can specifically display all kinds of postoperative spinal complications, and is of significant value in the diagnosis and differentiated diagnosis of postoperative spinal complications.

To determine the characteristics of magnetic resonance (MR) signals of normal growing cartilage and identify the difference in transverse relaxation times between physeal and epiphyseal cartilage in vivo. 24 distal femora of 12 two-week-old piglets were imaged on a 1.5 Tesla GE MR scanner. Comparison was made between signal intensity on MR images and the structure shown in corresponding histologic sections. T2 values were measured in eight piglets by means of multiecho spin-echo sequences. Our results showed that MR imaging delineated five regions between the secondary ossification center and the metaphysis, which histologically correspond to the zone of provisional calcification of the secondary ossification center, physis of the secondary ossification center, epiphyseal cartilage, physis and zone of provisional calcification. The T2 value in the physeal cartilage was much larger than that in the epiphyseal cartilage (P<0.05). It is concluded that MRI findings could differentiate the different regions of growing cartilage. T2 is longer in physeal than in epiphyseal cartilage, perhaps reflecting differences in water binding by proteoglycans.
Animals, Newborn ; Femur/anatomy & histology ; Femur/growth & development ; Femur/metabolism ; Growth Plate/*anatomy & histology ; Growth Plate/*growth & development ; Growth Plate/metabolism ; *Magnetic Resonance Imaging ; Osteogenesis/physiology ; Swine

Objective To determine the prevalence of fatigue among taxi drivers in Kunming city,to better understand their general working and health conditions,and to determine the risk factors associated with fatigued driving.Methods A total of 400 taxi drivers were randomly selected for participation in a self-administered questionnaire survey,which included height and weight measurements.The response rate was 88.3％.The survey consisted of four main categories:personal particulars,social habits,work patterns and sleep profile.The Epworth Sleepiness Scale was used to estimate the level of daytime sleepiness and fatigue.Multiple logistic regression analysis was used to estimate the adjusted odd ratios and 95％ confidence interval associated with risk factors related to fatigue among taxi drivers.Results A high proportion of taxi drivers were obese and had self-reported hypertension,diabetes mellitus and high cholesterol.Driver fatigue was associated with very poor/poor self-rating of quality of sleep,having an additional part-time job,and driving more than 10 hours a day.Conclusion The findings of the present study will improve awareness of the work and health conditions of taxi drivers,and contribute toward efforts to achieve a healthier workforce.A lower prevalence of fatigued driving may lead to lower risks of road traffic accidents,lower economic loss,higher productivity,and safer roads for all.

Pain is the common complication in the process of orthodontic treatment, which brings a lot of trouble to patients and doctors. In recent years, many scholars have studied many methods to alleviate orthodontic pain, such as drugs, laser irradiation, using new materials and some psychological therapy. This article will summarize the relief of orthodontic pain from two aspects of relieving physical and psychological discomfort.

An experimental animal model of malignant soft-tissue tumor was established to investigate the applied value of multi-slice spiral CT perfusion imaging preliminarily. Ten New Zealand white rabbits which were implanted with VX2 tumor in either proximal thigh were subjected to CT plain scan and perfusion scan two weeks later respectively, then the original perfusion images were transmitted to AW4.0 Workstation. The functional maps and perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were computed and analyzed. All the values of BF, BV and PS in VX2 soft-tissue tumors were obviously higher while the MTT-values were lower than those in the normal muscular tissues significantly. It was suggested that multi-slice spiral CT perfusion imaging is an accurate, convenient and relatively safe functional imaging technique, and can give a quantitative assessment to angiogenesis and blood perfusion of soft-tissue tumors.