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Objective:To demonstrate whether image quality and measurement accuracy of vessel wall thickening could be improved using a deep learning image reconstruction (DLIR) algorithm in children with Takayasu arteritis.Methods:From September 2019 to April 2020, 32 patients with Takayasu arteritis underwent low-dose contrast-enhanced CT with 100 kVp in Beijing Children′s Hospital were enrolled retrospectively. The raw data were reconstructed at 0.625 mm slice thickness using the filtered back projection (FBP), 50% adaptive statistical iterative reconstruction-V (ASIR-V) at 50% (50%ASIR-V), ASIR-V at 100% (100%ASIR-V) and DLIR. Subjective evaluation including the image quality of vessel wall identification, overall image noise and diagnostic confidence were evaluated using a 5 points scales by 2 observers. Objective evaluation including the thickness and standard deviation of vessel wall were measured, then the coefficient of variation (CV) was calculated. The CT value and noise of aorta were measured to calculate the contrast to noise ratio (CNR) of image. Friedman test was used to compare the differences of subjective scores among the four groups, and the analysis of variance of random blocks was used to compare the differences of objective measurement indices.Results:In terms of subjective score results, there was no significant difference between 100%ASIR-V and DLIR of overall image noise ( P>0.05), and the image scores of the two groups were higher than those of FBP and 50%ASIR-V (all P<0.05). The vessel wall identification and diagnostic confidence of DLIR were higher than those of other images (all P<0.05). The objective measurement results showed that the standard deviation and CV of vessel wall thickness in DLIR were significantly lower than those in other images (all P<0.05). There was no significant difference in vascular noise, muscle noise and CNR between 100%ASIR-V and DLIR (all P>0.05), which were lower than those in FBP and 50%ASIR-V (all P<0.05). Compared with 50%ASIR-V, the CV of DLIR was reduced by 22.9%, and the CNR was increased by 46.8%. Conclusion:DLIR can improve the overall image quality of CECT in children with Takayasu arteritis and the measurement accuracy of vascular wall, making it possible to further reduce the radiation dose.
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Objective To analyze the CT and MR imaging characteristics of the subcutaneous and organ lesions of uvenile xanthogranuloma (JXG) in children.Methods The CT and MR images of the head,chest,abdomen and subcutaneous soft tissue of 11 patients (6 females and 5 males,aged 2 months-12 years old,median age 8 months old) with JXG from 2006 to 2018 were collected and retrospectively analyzed.Eight patients underwent CT scan and/or contrast-enhanced CT scan,and 7 patients underwent MRI and/or MRI and contrast-enhancement MRI.Results In 11 cases of JXG,5 cases were classified as simple skin type,involving the skin and deep soft tissue in the right posterior neck,the right frontal and parietal parts of the head,the nose root,and the fat layer and the deep muscle in the extremities.The lesions were the subcutaneous soft tissue nodules or mass showing isodensity on CT or high signal on T2WI.And the other 6 cases were classified as systemic type whose lesions involved one or more than one part except the skin.In the 6 cases,3 cases involved the central nervous system,including the pituitary gland,cerebral hemisphere,cerebellum,brain stem,basal ganglia,thalamus,optic chiasma and spinal cord.The lesions of the pituitary gland were manifested as pituitary enlargement,thickening of the pituitary stalk,and disappearance of high signal on T1WI in the neurohypophysis.The brain parenchyma,the spinal cord and the optic chiasma showed multiple flake or nodular masses,which were iso/low signal on T1WI,low / high signal on T2WI,diffusion restricted,and enhanced markedly.Two cases involved lung tissue,and their lesions showed diffuse or scattered multiple cloudy shadow,reticular opacity,strip and small nodule shadow on chest CT.There was pleural effusion in one case.Two cases involved the livers and 2 cases involved the kidneys,showing multiple nodules with low signal on T2,WI and slight enhancement.One case involving the pancreas showed a low density in the head of the pancreas and slight enhancement on CT.One case involving the greater omentum,chest wall and peritoneum showed thickening of the corresponding tissues on CT.Conclusions Subcutaneous and systemic lesions of JXG show some characteristics on CT and MRI images.The main manifestations are single or multiple nodulars,which are diffusely distributed and vary in size in subcutaneous soft tissue and various organs.The combination of imaging appearances,clinical manifestations and biopsy has important clinical significance for the correct diagnosis and evaluation of JXG.
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To observe the transcriptional regulation of the two isoflavones genistein and daidzein on target genes.
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Teaching method of Problem-based Learning(PBL)is very popular now.PBL can arouse the enthusiasm and creativity of the students through carefully designed questions,focused discussions and related experiments etc.It can create an easy and active learning atmosphere thus it can improve the quality of teaching.
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The progress of modern science and technology stimulates reformation of teaching.PBL(Problem Based Learning) encourages the students to explore and solve the problems in the learning process.PBL can arouse the enthusiasm and creativity of the students through the carefully designed questions,focused discussions and(related) experiments etc.It can create an easy and active learning atmosphere that can improve the quality of teaching.
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Objective:To study the effect of corticotrophin-releasing hormone(CRH) on estrogen production in human trophoblasts and its mechanisms. Methods: Cytotrophoblasts were isolated from term human placentas and cultured for 72 h. The cultured cells were then treated with various concentrations of CRH and CRH receptor antagonist,?-Helical CRH9-41 for 24 h; estradiol was measured by radioimmunoassay in the culture media. Expression of aromatase(P450arom),the key enzyme for estrogen synthesis,was analyzed by Northern blot. Results: CRH significantly stimulated estradiol production and the expression of P450arom mRNA in placental cells. It was found that ?-Helical CRH9-41 blocked the effect of CRH and inhibited estradiol production and P450arom mRNA expression(P