Objective To investigate the application value of rice bag in 1.5T MR imaging of maxillofacial frequency selective saturated fat suppression(FS)sequence.Methods Forty-one patients with maxillofacial MR examination were collected.Rapid fast spin echo(FSE)FS T2 routine scan and rice bag FSE FS T2 special scan were used to evaluate and analyze the sequence images of the two kinds by two experienced associate chief physicians in the department according to the Likert 7-point scoring system.The evaluation included FS,magnetic sensitive artifact,motion artifact,and overall image quality.Wilcoxon sign rank sum test was used to analyze the difference of image quality scores,and Kappa consistency test was used to analyze the correlation between two viewers.Results All the 41 patients completed the examination,and the FSE FS T2 plus rice bag group had significantly higher FS,magnetic sensitive artifact,motion artifact and overall image quality than the conventional FSE FS T2 group,with statistical significance(P<0.01).Kappa consistency was good in correlation analysis between the two viewers(Kappa value=0.737-0.877,P<0.01).Conclusion The application of rice bag in the 1.5T MR maxillofacial FS sequence scan has the advantages of good image quality,good FS effect and few artifacts,which can better display the maxillofacial anatomical structure and lesions,and has important clinical application value for the diagnosis of maxillofacial diseases.

Objective To investigate the application value of ultrasound combined with MRI in the diagnosis of fetal urinary system abnormalities.Methods The clinical data of 647 cases of fetal urinary system abnormalities suspected by prenatal ultrasound were ana-lyzed retrospectively.All pregnant women underwent MRI examination within 2 days after ultrasound examination.Using pathology and follow-up as the gold standard,the accuracy and imaging features of ultrasound and MRI in detecting fetal urinary system abnor-malities were analyzed.Results Among 600 cases confirmed by pathology and follow-up,the accuracy of MRI,ultrasound and com-bined diagnosis of fetal urinary system abnormalities were 96.50％,96.67％,97.00％,sensitivity were 95.28％,96.23％,98.11％,and specificity were 96.76％,96.76％,96.76％,respectively.There were no significant differences in accuracy,sensitivity,specificity,positive predictive value and negative predictive value between MRI,ultrasound and combined diagnosis(P＞0.05).The area under the curve(AUC)of MRI,ultrasound and combined diagnosis of fetal urinary system abnormalities were 0.960,0.965 and 0.974,respectively,with no statistical significance(P＞0.05).Conclusion Compared with prenatal ultrasound,MRI also has a higher accuracy(96.50％)in the diagnosis of fetal urinary system abnormalities,and can be used as an important supplement to prenatal ultrasound.