Objective To investigate the application value of intravoxel incoherent motion (IVIM) MRI for evaluating the sensitivity of chemoradiotherapy on nasopharyngeal carcinoma (NPC). Methods Sixty eight consecutive patients newly diagnosed with NPC in the stage of T3 (30 patients) or T4 (38 patients) were retrospectively enrolled. They were divided into effective group (45 patients) and poor?effective group (23 patients) clinically after a standard chemoradiotherapy according to the RECIST criteria. IVIM with 13 b?values (range,0 to 800 s/mm2) and general MRI were performed at 3.0 T MR scanner before and after chemoradiotherapy. Two radiologists major in MRI diagnose analyzed all images independently and placed regions of interest (ROIs). Intraclass correlation coefficient (ICC) was used to evaluate intra?observer and inter?observer agreement. And Mann?Whitney test was used to assess the differences between the two groups. Results The reproducibility between intra?observer and inter?observer was relatively good. Statistically,D [(0.69±0.06)×10?3 mm2/s vs. (0.52±0.10)×10?3 mm2/s; U=51.5,P<0.01)] and D* [(161.33 ± 11.50)×10-3 mm2/s vs. (126.96 ± 10.27)×10-3 mm2/s; U=18.0, P<0.01] were significantly higher in effective group than those in poor?effective group, whereas the difference of f (16.68 ± 1.94% vs. 16.40±1.11%, U=434.5, P=0.282) and ADC (1.23±0.11)×10?3 mm2/s vs. (1.25±0.10)×10?3 mm2/s,U=427.0,P=0.240) could not reach statistical significance between the 2 groups (P>0.05). Conclusions IVIM may be potentially useful in assessing the chemoradiotherapy on NPC. The higher D value combined with higher D*value might indicate the chemoradiotherapy on NPC is more sensitive,and the higher D*value might reflect increased blood vessel generation and parenchymal perfusion in NPC.

Objective To investigate the morphological changes in the upper airway after bimaxillary surgery in patients with skeletal Class Ⅲ malocclusion and the relationship between jaw movement and airway changes using CBCT.Methods This study involved 44 individuals(21 males and 23 females)receiving Class Ⅲ bimaxillary surgery.Preoperative and 3-6-month postoperative CBCT data were examined using Dophin3D 11.95 software.The alterations before and after upper airway surgery were analysed using paired t-test and non-parametric Wilcoxon rank sum test.The association between airway alterations and jaw movement was examined using Pearson's correlation coefficient.Results Patients who underwent Class Ⅲ bimaxillary surgery had significantly reduced upper airway volume,sagittal cross-sectional area,and minimum cross-sectional area(P＜0.01).A correlation exists between oropharyngeal volume change and point B change(P＜0.05).When B point recession was＞7 mm,the decrease in upper airway volume increased significantly(P＜0.01),as did the risk of minimum cross-sectional area of the patient's airway(P＜0.01).Conclusion ClassⅢbimaxillary surgery re-duces upper airway capacity.Postoperative reduction in upper airway capacity coincides with mandibular recession.Mandibular reces-sion(＞7 mm)may reduce postoperative upper airway capacity and increase the risk of OSAHS.Patients at risk of upper airway stenosis should have their protocol modified to reduce airway risk.