Medical image analysis and 3-d modeling to quantify changes and functional restoration in denervated muscle undergoing electrical stimulation treatment

Background and purpose: Muscle tissue composition can be efficiently analyzed and quantified using images from spiral computed tomography technology (SCT) and the associated values of Hounsfield unit (HU) for different tissues. This work propose a novel approaches to monitor muscle condition in denervated muscle undergoing electrical stimulation (ES) treatment based on image segmentation and Three Dimensional (3D) modeling. Method: Three paraplegic patients with fully denervated muscles in the lower extremities were treated with ES. To follow changes in size, composition and shape of the quadriceps muscle, SCT scans are taken every 6 months from the trochanter major to the knee for 4 years. Using segmentation techniques we isolated rectus femoris muscle (RF) and analyzed its content of fat, connective, and muscle tissue. Results: The results showed the muscle restoration and growth induced by ES. The amount of normal muscle fibers increased from 45% to 60% of the whole volume while connective tissue and fat was reduced respectively of 30% and 50%. It was also found that muscles undergoing ES were restored in certain areas while declined in others depending on patient’s anatomy and positioning the surface electrodes. Conclusion: The 3D approach combined with muscle tissue analysis provides information on the whole muscle and on its structural changes during ES treatment otherwise not accessible with other monitoring techniques.