Transjugular Renal Biopsy Bleeding Risk and Diagnostic Yield: A Systematic Review

This study aimed to better define the safety and efficacy of transjugular renal biopsy (TJRB) based on published studies. Seventeen published articles were included (1,321 biopsies). Complications were classified as major if they resulted in blood transfusion or additional invasive procedures. All other bleeding complications were considered minor. Diagnostic tissue was obtained in 1,193 procedures (90.3%). The total incidence of bleeding complications among 15 articles with complete data was 202 of 892 procedures (22.6%): 162 (18.2%) minor and 40 (4.5 %) major. These results show that TJRB is a feasible procedure for obtaining renal tissue for diagnosis and that most complications are self-limiting.     

基于互信息的医学图像配准实验

基于互信息的配准方法，包括互信息和归一化互信息方法，是目前医学图像配准中无创、自动且精度很高的一种方法。已经被广泛应用。但是在其目标函数中存在着一定程度的幅值振荡现象。特别是在单模态图像配准中。我们研究发现，产生这种振荡的原因除了插值赝像外，还有由配准过程中图像重叠部分发生变化而引起的熵的变化不确定性。由插值赝像所带来的振荡基本上可以被消除掉；由熵的变化不确定性所带来的振荡很难被消除，但是这种振荡作用在归一化互信息中影响不大。归一化互信息比互信息具有更高的稳健性，适合于更广的应用范围。     

Supplementary formulas and tables for calculating and interconverting speech recognition scores in transformed arcsine units

Formulas that convert speech recognition scores, in percent or proportions, into units based on the arcsine transform have been described previously. This report reviews that work and presents various supplementary equations and tables for calculating and interconverting the proposed units. The relative merits of these data and their application to scores from closed-set tests are also discussed.     

Normalized gradient fields for nonlinear motion correction of DCE-MRI time series

Dynamic MR image recordings (DCE-MRI) of moving organs using bolus injections create two different types of dynamics in the images: (i) spatial motion artifacts due to patient movements, breathing and physiological pulsations that we want to counteract and (ii) signal intensity changes during contrast agent wash-in and wash-out that we want to preserve. Proper image registration is needed to counteract the motion artifacts and for a reliable assessment of physiological parameters. In this work we present a partial differential equation-based method for deformable multimodal image registration using normalized gradients and the Fourier transform to solve the Euler–Lagrange equations in a multilevel hierarchy. This approach is particularly well suited to handle the motion challenges in DCE-MRI time series, being validated on ten DCE-MRI datasets from the moving kidney. We found that both normalized gradients and mutual information work as high-performing cost functionals for motion correction of this type of data. Furthermore, we demonstrated that normalized gradients have improved performance compared to mutual information as assessed by several performance measures. We conclude that normalized gradients can be a viable alternative to mutual information regarding registration accuracy, and with promising clinical applications to DCE-MRI recordings from moving organs.     

Assessment of inflamed synovial membrane in the knee joint by dynamic magnetic resonance imaging

Dynamic magnetic resonance imaging (dynamic MRI) was used to examine the synovial membrane in the knee joints of 15 patients with rheumatoid arthritis (RA) in order to investigate the relationship between pathological and MRI findings. Signal intensities in the regions of interest (ROI), identified as the synovial membrane of the suprapatellar pouch, were measured on MR images. Signal intensities at various times after the injection of contrast medium Gd–diethylenetriaminopentoacetic acid (Gd–DTPA) were normalized relative to the signal intensity at 80s, and designated as the normalized signal intensity (NSI). Pathological findings were quantified, and the types of inflamed synovial membrane were classified as either acute or chronic. A significant difference in NSI was observed between acute and chronic types (P 0.05). Dynamic MRI was capable of classifying acute and chronic RA by measuring NSI 20s after contrast medium injection. Dynamic MRI was therefore shown to be useful for assessing regional synovial inflammation.     

Extremely Elevated International Normalized Ratio of Warfarin in a Patient with CYP2C9*1/*3 and Thyrotoxicosis

A 73-yr-old Korean man with permanent atrial fibrillation visited outpatient clinic with severely increased International Normalized Ratio (INR) values after taking a usual starting dosage of warfarin to prevent thromboembolism. We found out later from his blood tests that he had hyperthyroidism at the time of treatment initiation. His genetic analysis showed CYP2C9^*1/^*3 and VKORC1+1173TT genotypes. We suspect that both hyperthyroidism and genetic variant would have contributed to his extremely increased INR at the beginning of warfarin therapy. From this case, we learned that pharmacogenetic and thyroid function test might be useful when deciding the starting dosage of warfarin in patients with atrial fibrillation.

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