Objective: To investigate CT and MRI manifestations of Langerhans cell histiocytosis (LCH) involving the liver in children. Methods: CT and MRI findings of 22 children with LCH involving the liver were retrospectively analyzed. Results: Hepatomegaly was found in all 22 children, while widening of Glisson sheath and track sign and halo sign of portal area were observed in 20 cases. CT showed low density in 16 cases, 5 cases showed mild to moderate enhancement, and MRI showed high signal intensity in 4 cases and 2 cases showed mild enhancement of T2WI. Fourteen children presented multiple nodules in the liver, with diameters of 0.51-2.35 cm, distributed along the portal vein in 10 cases and diffusely distributed in 4 cases. Among them, CT showed low densities in 11 cases and 5 cases showed mild to moderate enhancement, while T1WI showed low signal intensities and T2WI showed high signal intensities in 3 cases and 2 cases showed mild enhancement. Intrahepatic bile duct alternative stenoses/dilatation were noticed in 8 cases. Conclusion: CT and MRI findings of LCH involving the liver in children have certain characteristics.

Objective To investigate the application value of magnetic resonance diffusion tensor imaging (DTI) in auditory pathway of sensorineural hearing loss (SNHL) infants caused by cytomegalovirus (CMV) infection.Methods Thirtyone SNHL infants caused by CMV infections were included,and were divided into bilateral hearing loss (BPHL;n=13) group and unilateral hearing impairment (UPHL;n=18) group (including damaged side [lpsi subgroup] and the undamaged side [contrast subgroup]).Thirty-one infants without hearing loss as control group.The fractional anisotropy (FA),the mean diffusivity (MD),the axial diffusivity (AD) and the radial diffusivity (RD) of bilateral inferior colliculus (IC)and lateral lemniscus (LL) were obtained with DTI technique.The statistical analysis was performed.Results Compared with the control group,the FA value reduced and the RD value increased at LL and IC in the BPHL group (all P＜0.001).Compared with the contrast subgroup,the FA value reduced and the RD value increased at IC and LL in lpsi subgroup (all P＜0.001).Compared with the control group,the FA value reduced at LL in the lpsi subgroup,and FA values reduced and RD value increased at IC (all P＜0.001).Compared with the contrast subgroup,the FA value reduced and RD value increased at LL,and RD value increased at IC in the BPHL group (all P＜0.001).The FA value at IC was negatively correlated with auditory threshold (r=-0.966,P＜0.001).No matter in IC or in LL,the MD and AD had no statistical differences (all P＞0.05).Conclusion White matter of auditory pathway of SNHL infant caused by CMV infection is obviously altered,suggesting white matter myelination or myelin dysplasia.

Objective To explore the value of 3D black bone sequence for measuring femoral head extrusion index and evaluating Herring classification of Legg-Calvé-Perthes disease(LCPD).Methods Data of hip joint MRI of 38 children with unilateral LCPD were retrospectively analyzed.Femoral head extrusion indices derived from coronal 3D black bone sequence and coronal fat suppression T2WI were compared to those from anteroposterior hip X-ray,respectively.Taken hip X-ray film as gold standards,receiver operating characteristic(ROC)curve was drawn,and the area under the curve(AUC)was calculated to evaluate the efficacy of 3D black bone sequence and fat suppression T2WI for evaluating Herring classification of LCPD,and DeLong test was performed for statistical comparison.Results Femoral head extrusion index of LCPD based on X-ray film and 3D black bone sequence simulated X-ray film was(11.31±6.16)％and(11.47±5.83)％on control side,respectively,being not significantly different(P＞0.05),while was(22.45±9.21)％and(22.82±7.92)％on the affected side,respectively,also being not significantly different(P＞0.05)but both higher than that on the control side(both P＜0.001).Femoral head extrusion index of LCPD based on fat suppression T2WI was(28.01±2.01)％on affected side and(27.25±1.92)％on control side,respectively,being not significantly different(P＞0.05)and both higher than those obtained based on X-ray film(both P＜0.001).AUC of 3D black bone sequence and fat suppression T2WI was 0.750-0.938 and 0.625-0.705,respectively.AUC of 3D black bone sequence for evaluating LCPD Herring B type was higher than that of fat suppression T2WI(P＜0.05),while no significant difference was found for evaluating other Herring type of LCPD(all P＞0.05).Conclusion 3D black bone sequences could be used to measure head extrusion index and assess Herring classification of LCPD,which was expected to replace hip X-ray to some extents combining with fat suppression T2WI.