Navigated anterior cruciate ligament replacement: an experimental validation study

We wanted to test the following hypothesis: the location of the tibial and femoral ACL attachments measured by a navigation system differs from their actual anatomic location. A total of 10 gross specimens were studied. The standard navigated procedure was used. Metallic reference pins were implanted around the tibial and femoral ACL attachments and palpated with a navigated stylus. Their position was recorded in comparison with the same tibial or femoral reference point. All measurements were repeated with a caliper. Caliper and navigated measurements were compared with appropriate statistical tests at a 0.05 level of significance. There was a significant difference between caliper and navigated measurements at the tibia in absolute value (maximal range of 4 mm, mean difference about 2 mm), but the difference ratio was low (about 3%); there was no significant difference between caliper and navigated measurements at the femur. There was a strong correlation and a good agreement between caliper and navigated measurements. It is likely that these differences have few, if any, clinical relevance. We demonstrated that the navigation system used during the present study has the potential to enhance the precision of the intra-operative measurement of the tunnel placement during ACL replacement.     

Epigenetische Pathomechanismen der Epileptogenese

Recent studies point to a pathogenic role of epigenetic chromatin modifications during epileptogenesis. Epigenetic mechanisms are covalent posttranslational modifications of histone proteins and DNA, which can produce lasting alterations in chromatin structure and gene expression. They are increasingly recognized as fundamental regulatory processes in central nervous system development, synaptic plasticity, and memory, and also play a role in neurological disorders, such as schizophrenia or spinal muscular atrophy. The authors propose that the “methylation hypothesis??addresses the intriguing issue of seizure-induced epigenetic chromatin modifications, which aggravate the epileptogenic condition by targeting candidate epileptogenesis gene expression. Unravelling epigenetic pathomechanisms will open also new strategies to identify molecular targets for pharmacological treatment in epilepsies. This project will be supported by EpiGENet, one of four consortia from the newly established European EuroEPINOMICS initiative.     

Liver segmentation for contrast-enhanced MR images using partitioned probabilistic model

Purpose  

Liver volume segmentation is important in computer assisted diagnosis and therapy planning of liver tumors. Manual segmentation is time-consuming, tedious and error prone, so automated methods are needed. Automatic segmentation of MR images is more challenging than for CT images, so a robust system was developed.