We present a case of retrocaval ureter and its MR appearances. This is the first case in reported literature. The findings on i.v. urography are correlated with the MRI findings. So far CT has been the procedure of choice to confirm the diagnosis of retrocaval ureter. However, we believe MRI is likely to replace CT in the diagnosis of retrocaval ureter.

No abstract

This instrument is useful for internal or external operations on the nose. The tube is smaller at the distal end, which prevents the tube from becoming clogged by chips of bone and blood clots as an ordinary tube often does. The end of the tube is smooth and bulbous. This instrument will fit the ordinary Nasal suction tube.

No abstract

Background: There is growing evidence for the use of augmented reality (AR) in pedicle screw placement in spinal surgery to increase surgical accuracy, improve clinical outcomes and reduce the radiation exposure required for intraoperative navigation. Auto-segmentation is the cornerstone of AR applications because it correlates patient-specific anatomy to structures segmented from preoperative computed tomography (pCT) images. These AR techniques allow for a reduction in the radiation dose required to acquire CT images while maintaining accurate segmentation. Methods: In this study, we methodically increase the noise that is introduced into CT images to determine the image quality threshold that is required for auto-segmentation on pCT. We then enhance the images with denoising algorithms to evaluate the effect on the segmentation. Results: The pCT radiation dose is decreased to below the current lowest clinical threshold and the resulting images still produce segmentations that are appropriate for input into AR applications. The application of denoising algorithms to the images resulted in increased artifacts and decreased bone density. Conclusions: The CT image quality that is required for successful AR auto-segmentation is lower than that which is currently employed in spine surgery. Future research is required to identify the specific, clinically relevant radiation dose thresholds.