Novel use of laser Doppler imaging for investigating epicondylitis

Objective. This investigation evaluated a novel form of tissue perfusion me asurement, laser Doppler imaging (LDI), in a case of lateral epicondylitis to establish if it might have applications in assessing soft tissue lesions . LDI was used in conjunction with ultrasonography to provide information a bout tissue oedema as well as the power Doppler signal as an alternative me thod of assessing blood flow. Methods. A laser Doppler imager with a near-infrared (NIR) laser source was used to improve tissue penetration and yield measurements of perfusion (Au x) from structures under the skin. Skin temperature over the lateral epicon dylar region was also measured. Ultrasonography was used in both grey-scale and power Doppler modes. LDI, temperature measurements and ultrasonographi c data were obtained before treatment and serially after local injection of methylprednisolone. Results. Before treatment there was increased perfusion and skin temperatur e and the presence of a power Doppler sign associated with the right latera l epicondyle as well as oedema at the extensor origin. None of these was pr esent at the asymptomatic contralateral epicondylar region. Twenty-four hou rs after methylprednisolone administration, both perfusion and skin tempera ture had increased, and they declined over the subsequent 48 h. Although sk in temperature had declined to normal (referenced to the contralateral epic ondyle) by the third day after injection, it took until the eleventh day af ter injection for perfusion to normalize. Conclusions. LDI using an NIR laser source appears to be an effective non-i nvasive method for the examination of inflammatory responses in soft tissue , with greater sensitivity than thermally based methods. In addition, LDI w as found to correlate with power Doppler ultrasonography.