Quantitative Computed Tomography and image analysis for advanced muscle assessment

Medical imaging is of particular interest in the field of translational myology, as extant literature describes the utilization of a wide variety of techniques to non-invasively recapitulate and quantity various internal and external tissue morphologies. In the clinical context, medical imaging remains a vital tool for diagnostics and investigative assessment. This review outlines the results from several investigations on the use of computed tomography (CT) and image analysis techniques to assess muscle conditions and degenerative process due to aging or pathological conditions. Herein, we detail the acquisition of spiral CT images and the use of advanced image analysis tools to characterize muscles in 2D and 3D. Results from these studies recapitulate changes in tissue composition within muscles, as visualized by the association of tissue types to specified Hounsfield Unit (HU) values for fat, loose connective tissue or atrophic muscle, and normal muscle, including fascia and tendon. We show how results from these analyses can be presented as both average HU values and compositions with respect to total muscle volumes, demonstrating the reliability of these tools to monitor, assess and characterize muscle degeneration.This research has been supported by the University Hospital Landspitali Scientific fund.Peer reviewe

SMM tækni : innleiðing, mat og ný aðferð til að bæta undirbúning skurðaðgerða

Every year more than 100 brain surgeries are performed at the neurosurgical department at Landspitali University Hospital (LSH). In many cases the use of a technology called Diffusion Tensor Imaging (DTI) tractography would be beneficial in surgical planning to visualize the nerve fibers preoperatively and as well intraoperatively associated with surgical navigation systems. The present work aims are: 1) to assess which conditions are needed at LSH in order to integrate DTI tractography in neurosurgical planning 2) develop a process that allow to combine DTI tractography and 3D printing technology that can improve surgical planning. Magnetic Resonance images (MRI) were acquired from 4 subjects with low grade glioma on a 1.5 T Siemens Avanto system. The image protocol included: 1) T1-weighted gradient echo structural and 2) echo planar imaging (SE-EPI) based diffusion tensor imaging (DTI) sequence with 20 diffusion directions. Five eloquent fiber tracts (Corpus callosum, Motor tracts, Sensory tracts, Optic tracts and arcuate fasciculus) were traced for all patients using two different DTI software platforms. A grading system was developed to rate anatomic accuracy and incorrectly displayed fibers tracts. Additionally a quantitative assessment in 3D was performed between the tracts volume in the two software systems. The results show that the DTI planning performed with different software platforms can provide diverse results. Even within the same software some tracts may result of better quality compared to others. In this work corpus callosum received the highest score. The results from the volumetric comparison show that in some case there are missing parts of a tract that can be important for surgical planning such as arcuate fasciculus. Moreover, this work demonstrate that the 3D printing process may be integrated with DTI planning and add valuable information for neurosurgical planning especially when associated to navigation systems. Finally, the results of this study show the variability of DTI planning between different software platforms and its unreliability in some cases, mostly because of the false positive results. Concluding, this study suggests a careful analysis and evaluation of the software platform before purchase

Recovery from muscle weakness by exercise and FES: lessons from Masters, active or sedentary seniors and SCI patients.

To access publisher's full text version of this article click on the hyperlink belowMany factors contribute to the decline of skeletal muscle that occurs as we age. This is a reality that we may combat, but not prevent because it is written into our genome. The series of records from World Master Athletes reveals that skeletal muscle power begins to decline at the age of 30 years and continues, almost linearly, to zero at the age of 110 years. Here we discuss evidence that denervation contributes to the atrophy and slowness of aged muscle. We compared muscle from lifelong active seniors to that of sedentary elderly people and found that the sportsmen have more muscle bulk and slow fiber type groupings, providing evidence that physical activity maintains slow motoneurons which reinnervate muscle fibers. Further, accelerated muscle atrophy/degeneration occurs with irreversible Conus and Cauda Equina syndrome, a spinal cord injury in which the human leg muscles may be permanently disconnected from the nervous system with complete loss of muscle fibers within 5-8 years. We used histological morphometry and Muscle Color Computed Tomography to evaluate muscle from these peculiar persons and reveal that contraction produced by home-based Functional Electrical Stimulation (h-bFES) recovers muscle size and function which is reversed if h-bFES is discontinued. FES also reverses muscle atrophy in sedentary seniors and modulates mitochondria in horse muscles. All together these observations indicate that FES modifies muscle fibers by increasing contractions per day. Thus, FES should be considered in critical care units, rehabilitation centers and nursing facilities when patients are unable or reluctant to exercise.European Regional Development Fund-Cross Border Cooperation Programme Slovakia-Austria (Interreg-IVa), project Mobilitat im Alter, MOBIL Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Austria Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria Faculty of Physical Education and Sports, Comenius University in Bratislava, Slovakia Austrian national cofinancing of the Austrian Federal Ministry of Science and Research Ludwig Boltzmann Society (Vienna, Austria) EU Commission Shared Cost Project RISE - Austrian Ministry of Science United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute of Arthritis & Musculoskeletal & Skin Diseases (NIAMS