Objective To discuss the image characteristics of enlarged prostatic utricle in children.Methods 13 children with enlarged prostatic utricle were retrospectively analyzed,6 of whom checked by voiding cystic urethrography (VCUG),5 of whom by MRI,2 of whom by both VCUG and MRI.Results 8 cases with VCUG showed round-like or long circle utricle filled with contrast media located in the rear posterior urethra.Among them,3 cases showed the tubiform between utricle and posterior urethra.The other 5 cases displayed overlap between utricle and urethra,and there was no tubiform between utricle and posterior urethra.7 cases with MRI showed oblong cyst at the right rear middle of the bladder that showed low signal with T1 weighted image and high signal with T2 weighted image,crossing the center of prostate gland.Among them,5 cases showed the communication between oblong cyst and posterior urethra.Also,among them,5 cases were associated with the orchitis,epididymis phlogistic,scrotal phlogistic,and 1 case showed the right renal agenesis.Conclusion The VCUG and MRI are helpful to check enlarged prostatic utricle in children.They have different advantages in different aspect.

Objective To explore the MRI features of Langerhans cell histiocytosis (LCH) in central nervous system (CNS) in children. Methods Clinical and MRI data of 25 cases with LCH in CNS from three children's hospitals between January 2009 and December 2014 were retrospectively studied. All cases were confirmed by surgery or biopsy. All cases underwent non?contrast and contrast pituitary and/or cranial MRI examinations. The location, morphology, MRI signal and enhanced patterns of LCH lesions were observed and analyzed. Result A total of 17 cases had hypothalamic-pituitary LCH, with 2 of them complicated with pineal cyst, 2 complicated with brain parenchymal lesions, and one complicated with both pineal cyst and brain parenchymal lesions. MR images showed that neurohypophysis lost its original hyper?intensity on T1WI, and nodular or homogeneous thickening was seen in the pituitary stalks. Dura matter was involved in 3 cases, 2 of them had single lesion, and the other one got multiple lesions. Neoplasm in choroid plexus was seen in trigone of left lateral ventricles in one case. Three cases with pineal gland involved demonstrated cystic change. Four cases had gray matter involved, with cerebellar dentate nuclei involvement in 2 cases, and both thalamus and basal ganglia involvement in the other two cases. Three cases showed white matter involvement without obvious Virchow-Robin space enlargement and brain atrophy. Conclusions MR imaging of LCH in CNS shows certain specific characteristics. The diagnosis can be made comprehensively based on both clinic features and other imaging findings.

Objective To investigate the value of combined 3D-constructive interference in steady state(3D-CISS) with phase-contrast MR(PC-MR) in diagnosis of hydrocephalus children.Methods We collected retrospectively 28 children with hydrocephalus who caused by obstructive membranes.They all underwent MR imaging examination with a 1.5 T consisting of 3D-CISS, conventional sequences and PC-MR.With the result of surgery and CT cisternography as gold standard,we analysised different sequence in the diagnosis of membranous obstruction.The results of obstructive were analysed by x2 test between 3D-CISS combined with PC-MR and conventional sequences.Results The study included 28 children, of whom 16 showed obstructive membranes in CSF pathways of ventricle and 12 displayed obstructive membranes in CSF pathways of cistern.Conventional sequences diagnosed obstructive membranes of 15 children, and obstructive membranes of 11 children were consistent with gold standard, and 4 cases were false positive.The 3D-CISS diagnosed obstructive membranes of 40, and 12 cases were false positive.There were significant difference between 3D-CISS combined with PC-MR and conventional sequence about obstructive membranes diagnosis of CSF pathways(x2=24.410, P=0.001).Conclusions Making use of jointing 3D-CISS sequence and PC-MR sequence successively, and we can diagnose the position of obstructive membrane for hydrocephalus, which can be helpful to select a perfect surgical approach.

Objective To study MRI manifestations of cerebral developmental venous anomaly (DVA)and to analyze the diagnos-tic value of different sequences.Methods Conventional MRI and contrast enhancement 3D-T1 WI were performed in all 10 patients who were collected in our hospital.Among the 10 cases,6 patients underwent MRA and 4 patients underwent MRV.The diaplay of the draining veins and medullary veins were assessed.Results All 10 cases were sporadic lesion,the lesions of 9 cases were located in supra tentorium and which of 1 case was located in infra tentorium.Abnormal signals without characteristics of draining veins in 6 cases and dilated medullary veins in 4 cases were found in conventional MRI,while 6 draining veins showed flow void signal on T2 WI and 3 of the 4 medullary veins showed hypointensity on T1 WI and hyperintensity on T2 WI.Contrast enhancement 3D-T1 WI displayed the markedly enhanced draining veins and dilated medullary veins in all 10 cases of DVA.Numerous medullary veins gath-ered together into large draining veins radially and flowed into superficial or deeper veins,so-called“caput medusae”appearance were found as the characteristics in all cases.MRA and MRV revealed draining veins only partially but no medullary veins.Conclusion MRI could diagnose DVA clearly,the sensitivity of detecting DVA on conventional MRI is low and there are no characteristics ap-pearances.Contrast enhancement 3D-T1 WI is the most accurate and sensitive method,MRA and MRV are not highly worthwhile for diagnosing DVA.

Objective To determine the effect of reducing the value of mA or kV on the image quality and the radiation dose of the patients undergoing low-dose spiral CT for orthodontics.Methods Thirty patients were divided into three groups,each group has 10 patients.They were group 1(80 kV and 200 mA),group 2 (120 kV and 80 mA),group 3(120 kV and 200 mA)The volume CT dose index(CTDI)was recorded and the average dose-length produce(DLP)was calculated in three groups,respectively.Image quality of three groups were compared and scored by two radiologists,and the results were statistically analysed.Results The CTDI among three groups in diagnostic image quality.Conclusions Low-dose spiral CT for orthodontics,especially the low-kV scan,may decrease the radiation exposure and guarantee the image quality.

Objective To investigate the objective factors that affect the image quality of infant cranial CT using different mAs. Materials and Methods Ninety infants were divided into three groups randomly. The maximum anteroposterior diameter (MAPD) of skull of each infant was measured. Three reference levels, cerebellar, basal ganglia and centrum semiovale levels were selected respectively. Only one level was studied in each group and scanned with 150, 100 and 80 mAs. The subjective quality grade and the objective noise of all images were recorded and analysed statistically. Result The average MAPD of ninety patients was (148.0 ± 17.4)mm. On the cerebellar level, the subjective quality grade was lower than the other two levels, which were 6.3% , 9.4% and 22.9% respectively when mAs were 150, 100 and 80 mAs. Both quality grade of image and objective noise were significantly correlated with MAPD.Conclusion The inherent high noise of cerebellar level and MAPD were the objective factors that affect the image quality of low-dose cranial CT of infant.

Objective:To investigate the value of CT findings of childhood hepatoblastoma (HB) in predicting preoperative tumor risk stratification.Methods:Totally 46 children with HB confirmed by surgery and pathology were retrospectively enrolled from October 2010 to October 2019 in Shenzhen Children′s Hospital and Xuzhou Children′s Hospital. The preoperative abdominal plain CT and three-phasic contrast-enhanced CT with complete clinical files were evaluated. According to the clinical risk stratification established by the multidisciplinary diagnosis and treatment consensus for children with HB, the HB children were divided into high-risk group and non-high-risk group with 16 and 30 cases respectively. The maximum diameter of tumor, relative tumor volume index, cystic change or necrosis, bleeding, calcification, fibrous septations, tumor rupture, liver capsule retraction and subcapsular effusion were evaluated. Enhancement percentage and enhancement index on arterial, venous and delayed phases of each tumor were measured and calculated. Pearson′s χ 2 test or Fisher′s exact test were used to compare the differences in gender and lesion morphological characteristics between the high-risk group and the non-high-risk group. Two independent sample t test or Mann-Whitney U test were used to compare the differences in age, gestational age, birth weight, α-fetoprotein, platelets, maximum diameter of tumor, relative tumor volume index and CT parameters of the lesion between the two groups. Statistically significant features were included in the binary logistic regression analysis and independent predictors related to high-risk group were obtained. The ROC curve was used to determine the critical value of the high-risk group. Results:There were statistically significant differences in age, maximum diameter of tumor, relative tumor volume index and tumor rupture between the high-risk group and the non-high-risk group (all P<0.05). The logistic regression analysis showed that the maximum diameter of tumor (OR=1.906, P=0.004) and tumor rupture (OR=16.558, P=0.005) were risk factors of the high-risk group. Based on ROC curve, the optimum cut-off point of maximum diameter of tumor to predict high-risk group was 10.5 cm. Tumor rupture, maximum diameter of tumor and maximum diameter of tumor combined with tumor rupture for predicting the incidence of high-risk group resulted in the area under the curve of 0.744, 0.807 and 0.879, respectively. The sensitivity and specificity of maximum diameter of tumor combined with tumor rupture were 75.0% and 96.7%, respectively. Conclusion:The age of onset in high-risk group is relatively older. The maximum diameter of tumor greater than 10.5 cm accompanied by tumor rupture can be regarded as a high-risk sign.