Analysis of Tarsal Tunnel Syndrome Using Image Correlation

Tarsal tunnel syndrome (TTS), also known as posterior tibial neuralgia is a painful disorder of the foot. It is a medical condition arising due to the compression of the tibial nerve in the tarsal tunnel, resulting in numbness, parenthesis and muscle weakness in foot. A number of imaging methodologies such as ultrasound as well as MRI imaging has been used in the past in order to analyze the strain pattern of gastrocnemius tendon and aponeurosis from the surface of the skin without analyzing the internal tendons. The DIC code developed, computes the in-plane strain with a correlation function using pictures taken before and after stretching, using a CCD camera. The shift between the initial picture and subsequent one is evaluated by cross-correlation using FFT. This paper gives in detail description of the preprocessing steps necessary to extract Zone of Interest from the two images. The effects of stretching on the superficial components of the tibial nerve, the posterior tibial artery and vein, and the tibialis posterior, flexor digitorum longus and flexor hallucis longus tendons in the calf and foot are studied.