Objective To investigate the clinical value of MRI in treatment choice of anterior disc displacement with reduction. Methods 1.5 T superconducting MR was used to scan bilateral temporomandibular joints in 72 consecutive patients who were diagnosed by MRI as unilateral(66 patients)/bilateral(6 patients) anterior disc displacement with reduction at closed and open mouth. MRI sequences included oblique sagittal T2 weighted image and proton density weighted image, and 78 joints' images were acquired. According to the severity of clinical symptoms, all joints were divided into severe symptom group (45 joints) and mild symptom group (33 joints). Treatment was performed in severe symptom group , while follow up was conducted in mild symptom group. Disk position(angle between posterior margin of the disc and the condyle vertical line), disk morphology(biconcave, biplanar, biconvex, rounded, folded, thick posterior band), and joint effusion (none effusion, mild effusion, moderate effusion, marked effusion) were evaluated by two radiologists. The observer agreement for image evaluation was calculated using Kappa statistics. Group difference in disk position was compared using t-test and Chi-square test was used to compare group difference in disk morphology and joint effusion. Results The Kappa value between two radiologists were 0.816 and 0.832 (P<0.01) on evaluation of disk morphology and joint effusion. Statistical results indicated that the angles between posterior margin of the disc and the condyle vertical line in severe symptom group (54.2 ± 10.9)° were larger than those in mild symptom group (46.4 ± 9.0)° (t=3.37, P<0.05). There was no significant difference in disc deformation incidence between the two groups (χ2=1.18,P=0.277). The common deformation in sever symptom group was thick posterior band (χ2=5.65, P<0.05), and in mild symptom group was biplanar (χ2=5.67, P<0.05). No statistical difference in joint effusion incidence was observed(χ2=1.02,P=0.312). Moderate and marked effusion were more common in sever symptom group than that in mild symptom group (χ2=6.55,P<0.05). Conclusions MRI is a useful tool for making treatment choice in anterior disc displacement with reduction. Treatment should be given when the following occurred on MRI:moderate anterior disc displacement, disc deformation (excepting for biplanar), moderate or marked joint effusion.

Objective To explore a promising system for tumor CD 44 receptor-targeted imaging and to investigate their physic-chemical properties and targeting effect on CD 44 abundant cancer cells in vitro.Methods The superparamagnetic iron oxide ( SPIO) nanoparticles were prepared by a coprecipitation in alkaline media starting from a mixed of the ferrous and ferric solution.And then the surface of the SPIO nanoparticles were modified with APTMS by a reaction with the hydroxyl groups.Finally, the hyaluronan-modified SPIO ( SPIO-HA) nanoparticles were prepared.Control and experimental groups were established after adding SPIO or SPIO-HA as agents respectively.Transmission electron microscopy ( TEM) and particle size analyzer were used to measure these nanoparticle sizes and the hydrodynamic diameters.Thermogravimetric analysis ( TGA) was carried out to evaluate the HA-content on the surface of SPIO-HA.The MRI T2 ralaxivities (1/T2 ) of the two groups at different Fe concentrations (0.09, 0.18, 0.27, 0.36, 0.45 mmol/L ) were measured on a 3.0T MR system.HepG2 cells and HL7702 cells were used for assessment of cells viability by methyl thiazolyl tetrazolium ( MTT ) assay.Prussian blue staining , immunoassay fluorescence image and flow cytometry were carried out to determine the targeted cellular uptake of SPIO-HA nanoparticles.MRI were performed to show the MR T 2 value changes after incubating with HepG2 cancer cells by using T 2 WI sequences at a clinical 3.0 T MR system.One-way analysis of variance was performed to determine significant changes in MR T 2 values of blank control , SPIO-HA and SPIO groups.Results The SPIO-HA and SPIO NPs were fairly homogeneous with an average core size of 18.2 and 22.4 nm, hydrodynamic diameter of 91.1 and 103.2 nm, Zeta potential of (-45.00 ±0.86) mV and (-18.50 ±0.73) mV, and magnetic relaxivity of 0.212 ×106 M-1 · s-1 and 0.191 ×106 M-1 · s-1.Based on the TGA data , HA accounted for 24%weight of each SPIO-HA.The internalization of the SPIO-HA was confirmed by prussian blue staining , while the cells showed no obvious blue stains with SPIO , incubation of SPIO-HA with tumor cells led to blue color inside the cells.After that, we examined cancer cell binding of FITC-SPIO-HA by immunoassay fluorescence image and flow cytometry.The green fluorescence resulting from FITC-SPIO-HA was observed inside the cells in both the cytoplasm and the plasmalemma.Tumor cells treated with SPIO-HA exhibited higher fluorescence signals with 7.97-fold enhancement observed for HepG 2 cells over control particles.In vitro MR, mean T2 values of blank control , SPIO and SPIO-HA groups were ( 115.20 ±0.36 ), ( 115.07 ±0.81 ) and ( 21.67 ±0.21 ) ms, respectively.There was significant difference among those three groups (F=31 703.339,P<0.01), MR T2 values of HepG2 cells treated with the SPIO-HA NPs were lower than blank and SPIO group.In comparison, SPIO did not generate any MRI signal changes compared with blank group.Conclusion The tumor CD44 receptor-targeted MR molecular probe SPIO-HA had a good physic-chemical property and well targeted HepG2 cells.