An Interesting Case of Recurrent Small Bowel Obstruction

Sclerosing mesenteritis is associated with a spectrum of diseases which include mesenteric lipodystrophy and mesenteric panniculitis. This inflammatory and fibrosing disorder can affect the small and large bowel wall and mesenteric vessels by exerting a mass effect. The following case highlights the difficulties with diagnosing and managing this unusual disease. A 64-year-old man presented with acute central abdominal pain, radiating to his back, and profuse vomiting. He was diagnosed clinically with small bowel obstruction. He had had an episode of small bowel obstruction 6 years earlier. At this time, he underwent an exploratory laparotomy, and a mass was identified in the small bowel mesentery. The features were thought to be in keeping with sclerosing mesenteritis. He had a dramatically favourable response to the initiation of prednisolone. He continued to be well and asymptomatic for a further 5 years on long-term maintenance low-dose steroids and 6-mercaptopurine. He re-presented in 2009 (six years after initial presentation) with very severe acute abdominal pain and vomiting. He had no recent change in weight or appetite, and had not had time off work. He underwent a second laparotomy and the tissue diagnosis was of metastatic carcinoid tumour involving the small bowel mesentery. This is the first case to our knowledge where sclerosing mesenteritis has been confirmed histologically on biopsy and then subsequently diagnosed with histologically proven carcinoid tumour. For this particular reason it must be always remembered that sclerosing mesenteritis is a ‘pathological’ and not a radiological diagnosis and that a large proportion of cases are associated with neoplasia

Quantifying internal stress and internal resistance associated with thermal ageing and creep in a polycrystalline material

In situ neutron diffraction combined with the incremental deformation at room temperature has been used to provide a measure of the internal stress and internal resistance generated by prior inelastic deformation at high temperature in an austenitic stainless steel. Interactions between the internal stress and internal resistance are considered explicitly by using the proposed measurement technique. The magnitude of the intergranular internal stress is found to be a function of the total inelastic strain created by prior high temperature deformation. The deviation from linearity observed in the lattice strain response is used to derive the microscopic internal resistance, but a crystal plasticity model is required to infer the absolute value. The macroscopic internal resistance is shown to be consistent with Taylor hardening. A refined internal state concept is proposed based on the Kocks–Mecking model to provide a further step to predict the inelastic deformation

Quantitative comparison of sinc-approximating kernels for medical image interpolation

Interpolation is required in many medical image processing operations. From sampling theory, it follows that the ideal interpolation kernel is the sinc function, which is of infinite extent. In the attempt to obtain practical and computationally efficient image processing algorithms, many sinc-approximating interpolation kernels have been devised. In this paper we present the results of a quantitative comparison of 84 different sinc-approximating kernels, with spatial extents ranging from 2 to 10 grid points in each dimension. The evaluation involves the application of geometrical transformations to medical images from different modalities (CT, MR, and PET), using the different kernels. The results show very clearly that, of all kernels with a spatial extent of 2 grid points, the linear interpolation kernel performs best. Of all kernels with an extent of 4 grid points, the cubic convolution kernel is the best (28% – 75% reduction of the errors as compared to linear interpolation). Even better results (44% – 95% reduction) are obtained with kernels of larger extent, notably the Welch, Cosine, Lanczos, and Kaiser windowed sinc kernels. In general, the truncated sinc kernel is one of the worst performing kernels