When applying deep learning algorithms to magnetic resonance (MR) image segmentation, a large number of annotated images are required as data support. However, the specificity of MR images makes it difficult and costly to acquire large amounts of annotated image data. To reduce the dependence of MR image segmentation on a large amount of annotated data, this paper proposes a meta-learning U-shaped network (Meta-UNet) for few-shot MR image segmentation. Meta-UNet can use a small amount of annotated image data to complete the task of MR image segmentation and obtain good segmentation results. Meta-UNet improves U-Net by introducing dilated convolution, which can increase the receptive field of the model to improve the sensitivity to targets of different scales. We introduce the attention mechanism to improve the adaptability of the model to different scales. We introduce the meta-learning mechanism, and employ a composite loss function for well-supervised and effective bootstrapping of model training. We use the proposed Meta-UNet model to train on different segmentation tasks, and then use the trained model to evaluate on a new segmentation task, where the Meta-UNet model achieves high-precision segmentation of target images. Meta-UNet has a certain improvement in mean Dice similarity coefficient (DSC) compared with voxel morph network (VoxelMorph), data augmentation using learned transformations (DataAug) and label transfer network (LT-Net). Experiments show that the proposed method can effectively perform MR image segmentation using a small number of samples. It provides a reliable aid for clinical diagnosis and treatment.
Objective The method of metabonomics based on nuclear magnetic resonance (NMR) imaging was used to explore the difference in metabolites of serum and bile, and to analyze the metabolic variation related to the pathogenesis of gallbladder stones between normal people/liver transplantation donors and patients with gallbladder stones. Methods Prospectively collected the serum samples (17 cases) and bile samples (19 cases) in 19 patients with gallbladder stones who underwent surgery in West China Hospital form March 2016 to December 2016, as well as the serum samples of 10 healthy persons and the bile samples of 15 liver transplantation donors at the same time period. The differences of metabolites in the blood and bile in these 3 groups were compared by using 1H-NMR metabonomics technology and chemometric methods. Results The concentrations of valine, alanine, lysine, glutamine, glutamate, pyruvate, creatinine, choline, alpha-glucose, beta-glucose, tyrosine, histidine, and hypoxanthine in serum of patients with gallbladder stones decreased significantly, comparing with those of healthy people without gallbladder stones (P<0.05), while 1, 2-propanediol, acetoacetate, and lactate increased significantly in the serum of patients with gallbladder stones (P<0.05). The concentrations of taurine conjugated bile acids, glycine conjugated bile acids, choline, and phosphatidylcholine decreased significantly in the bile of patients with gallbladder stones when compared with those of liver transplantation donors (P<0.05), while cholesterol increased significantly in the bile of patients with gallbladder stones (P<0.05). Conclusions There are significant differences of the serum and bile metabolites between patients with gallbladder stones and healthy men without gallbladder stones/liver transplantation donors. 1H-NMR metabonomics is helpful to investigate the pathogenesis of gallbladder stones.
OBJECTIVE:To investigate the diagnostic meaning of MRI in intraocular tumors. METHODS:Forty-six cases of confirmed intraocular tumors,including choroidal melanoma(20 cases),retinoblastoma(18 cases),Coats disease(6 cases)and choroidal hemangioma(2 cases),were studied with MRI and compared with ultrasonography and CT. RESULTS:In making discoveries about intraocular tumors,there were no sighificant difference between MRI and B-ultrasonography or CT （P＞0.03，chi;2=1.0716）while there were highly statistic sighificance in dediding characters and position （P＜0.01，deceding character chi;2=29.8314，positionchi;2=13.659）of them. CONCLUSION:Among the examinations to find out about the position,character and secondary pathological insults of in traocular tumors MRI might be more available than CT and ultrasonography. （Chin J Ocul Fundus Dis,1997,13:93-95 ）
Objective To evaluate the clinical value of cardiac MRI for the diagnosis of viral myocarditis (VMC). Methods Such databases as PubMed (1950 to 2009), EMbase (1974 to 2009), and The Cochrane Library (December 2009) were searched to include clinical research reports of diagnosing viral myocarditis with MRI. QUADAS items were used to evaluate the quality of the included studies. The Meta-disc software was used to conduct merger analyses on sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. The Heterogeneity test was performed and summary receiver operating characteristic curve (SROC) was completed. Results Five trials were included. The value of merger sensitivity, specificity, and diagnostic odds ratio (DOR) were 0.94, 0.69, 2.76, and 28.11, respectively. The area under of SROC curve (AUC) was 0.871 9. Conclusion The current evidence shows that cardiac MRI has high sensitivity (94%) and moderate specificity (69%) in the diagnosis of viral myocarditis. The positive rate in the viral myocarditis group is 28.11 times as high as that in the non-viral myocarditis group, so Cardiac MRI has good diagnostic values for viral myocarditis.
The effect of deep brain stimulation (DBS) surgery treatment for Parkinson's disease is determined by the accuracy of the electrodes placement and localization. The subthalamic nuclei (STN) as the implant target is small and has no clear boundary on the images. In addition, the intra-operative magnetic resonance images (MRI) have such a low resolution that the artifacts of the electrodes impact the observation. The three-dimensional (3D) visualization of STN and other nuclei nearby is able to provide the surgeons with direct and accurate localizing information. In this study, pre- and intra-operative MRIs of the Parkinson's disease patients were used to realize the 3D visualization. After making a co-registration between the high-resolution pre-operative MRIs and the low-resolution intra-operative MRIs, we normalized the MRIs into a standard atlas space. We used a special threshold mask to search the lead trajectories in each axial slice. After checking the location of the electrode contacts with the coronal MRIs of the patients, we reconstructed the whole lead trajectories. Then the STN and other nuclei nearby in the standard atlas space were visualized with the grey images of the standard atlas, accomplishing the lead reconstruction and nerve nuclei visualization near STN of all patients. This study provides intuitive and quantitative information to identify the accuracy of the DBS electrode implantation, which could help decide the post-operative programming setting.
ObjectiveTo analyse the seizure semeiology of MRI negative insular epilepsy.MethodsA case of patient with insular epilepsy who presented in Epileptic Center, Guangdong 999 Brain Hospital was collected. Related literatures were thoroughly reviewed.ResultsThe patient was diagnosised as insular epilepsy by SEEG and postoperative pathology reported focal cortical dysplasia Ib.ConclusionsThe insula lobe is a part of the limbic system, and the seizure semeiology in insular epilepsy is varied. Seizure semeiology analysis is particularly important in the evaluation of presurgical especially in a MRI negative case. In this paper, we summarized the semeiology characteristics of various parts of insula lobe, and provided some references for the diagnosis and treatment of insular epilepsy.
ObjectiveTo make the model of Wistar suckling rats Focal cortical dysplasia (FCD) by liquid nitrogen freezing brain cortex and verify it. Analysed the electroencephalogram (EEG) and magnetic resonance imaging (MRI) features of the FCD model, in order to provide theoretical and experimental basis for human FCD diagnosis and treatment. MethodsTake the first day of Wistar suckling rats as experimental object, liquid nitrogen freezing Wistar suckling rats brain cortex.Make examination of EEG and MRI for Wistar suckling rats. The Brain tissue slice of Wistar suckling rats model dyed by HE and check with light microscope examination. ResultsIn experiment group, the sample epileptic discharge rate of EEG was about 41.6% on average, and showed visible spike wave, spine slow wave frequency distribution. Experimental Wistar suckling rats MRI showed positive performance for long T1 and long T2 signal, brain tissue slices HE staining showed brain cortex layer structure and columnar structure disorder, exist abnormal neurons and the balloon sample cells. ConclusionThe method of liquid nitrogen freezing Wistar suckling rats cortex can established FCDⅢd animal models successfully, and showed specific EEG and MRI, which has important value for diagnosis and treatment of human FCD.