ABSTRACT
We report the case of a fetus with a sonographic diagnosis of hyperechogenic cerebellum at 28 weeks' gestation, which was suspected to be of hemorrhagic origin on fetal ultrasound. As an adjunct to ultrasound, fetal MRI can confirm the hemorrhagic origin of hyperechogenic cerebellar lesions, particularly by showing a high signal on T1-weighted images. No etiological factors for fetal hemorrhage were found other than maternal hypertension and aspirin use. Postnatal MRI confirmed the prenatal diagnosis of cerebellar hemorrhage without underlying vascular anomaly.
ABSTRACT
In our perinatology service, we observed two cases of cardiac papillary fibroelastoma in fetuses. This case-report focused on assessing the prenatal diagnosis and outcome of these two fetal cases in which cardiac fibroelastoma was initially identified via fetal echocardiography and subsequently confirmed by histopathological analysis.
Subject(s)
Aortic Valve , Cardiac Papillary Fibroelastoma , Ultrasonography, Prenatal , Humans , Female , Pregnancy , Ultrasonography, Prenatal/methods , Aortic Valve/diagnostic imaging , Adult , Cardiac Papillary Fibroelastoma/diagnostic imaging , Echocardiography/methods , Heart Neoplasms/diagnostic imagingABSTRACT
Some adjustments are made to design weights to reduce the negative effects of non-response and out-of-scope problems. The calibration approach is a weighting process that agrees with the known population values by using auxiliary information. In this study, alternative calibration approaches and weight trimming process that can be used in large data sets with extreme weights and different correlation structures were analysed. In addition, the effect of the correlation structure of auxiliary variables on the efficiency of the calibration estimators was investigated by a simulation study. The 2017 Annual Industry and Service Statistics data were used in the simulation study and it was seen that restricted calibration estimators were more efficient than the generalized regression estimator in estimating the variables with a high variance such as turnover. Especially in small sample fractions, we recommend the application of restricted calibration estimators, as they are more efficient than the weight trimming in solving the negative and less than one weights problem encountered after the calibration process.
