1138 AJR:185, November 2005 AJR 2005; 185:1138–1140 0361–803X/05/1855–1138 © American Roentgen Ray Society Cook et al. Vascularity of Tendons on Sonography After Exercise Musculoskeletal Imaging  Clinical Observations Is Vascularity More Evident After Exercise? Implications for Tendon Imaging Jill L. Cook 1 Z. Stephen Kiss 2 Ron Ptasznik 3 Peter Malliaras 1 Cook JL, Kiss ZS, Ptasznik R, Malliaras P DOI:10.2214/AJR.04.1205 Received July 29, 2004; accepted after revision November 10, 2004. 1 Musculoskeletal Research Centre, La Trobe University, Melbourne, Victoria 3086, Australia. Address correspondence to J. L. Cook (j.cook@latrobe.edu.au). 2 Medical Imaging Australia, Melbourne, Australia. 3 Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Australia. OBJECTIVE. The objective of our study was to investigate the effect of activity on tendon vascularity in 17 abnormal patellar tendons. CONCLUSION. Tendon vascularity is significantly increased by activity (p < 0.001). From this finding, we infer that imaging abnormal tendons with color Doppler sonography to detect neovascularization may be most useful after the patient exercises. Investigations to de- termine how much activity is necessary to ensure maximal vascularity is detected by Doppler sonography are required. eovascularization in abnormal ten- dons shown on Doppler sonogra- phy has a varied relationship with pain and outcome. Some studies have reported an absolute association [1] and others a less clear relationship [2–4]. Overall, however, these studies indicate that abnormal tendons with detectable vascularity seem to be more painful than those without vascularity. Imaging vascularity in tendons can be prob- lematic because the detection of vascularity with Doppler sonography is sensitive to muscle stretch and contraction, both of which can elim- inate detectable blood flow. This is now clearly understood, and most examiners now ensure a relaxed muscle when the tendon is imaged. The activity of the tendon before imaging may have a crucial effect on tendon vascu- larity when imaged with Doppler sonogra- phy. It is known that resting tendons have a low blood flow and that even exercise may increase it only submaximally [5]. To our knowledge, only one previous article has re- ported the effect of activity on tendons; that study examined patellar tendons of subjects before and after playing a basketball game [6]. Three of four tendons that were vascular after the game had vascularity before the game. It is unclear from that article how much change was apparent in those tendons because no attempt to quantify the change was made. Although there are now several articles on tendon vascularity, none of the authors have reported the activity of the person before im- aging or described a standardized warm-up before imaging. Tendon imaging is usually done in a clinical setting, often after the pa- tient has sat quietly waiting for examination for a variable period of time. If activity affects vascularity, then this tendon “quiet time” be- fore imaging may mean that all vascularity that is present in the tendon is not detected be- cause of a lack of blood flow in the vessels. This pilot study aimed to examine patellar tendons in subjects before and after playing a volleyball game and quantify the change in tendon vascularity due to intense activity of the musculotendinous unit. Materials and Methods Seventeen volleyball players (three grades rang- ing from elite to domestic competitions) with known tendon vascularity were taken from a larger cohort of players. Their patellar tendons were examined before and after (within 1 hr) a competitive game of volley- ball with sonography by an experienced musculosk- eletal radiologist. The examinations were performed with the subject supine and the knee extended, and care was taken to ensure relaxation of the quadriceps muscle. Approval for the study was gained from the La Trobe University Human Ethics Committee, and all subjects provided informed consent. Tendons were imaged in the sagittal plane with both gray-scale and color Doppler sonography us- ing a unit with a 13.5-MHz linear transducer (Acu- son CV70, Siemens Medical Solutions). Color Doppler settings were standardized with a gain of 68 dB, sensitivity of 8 cm/sec, and pulse repetition frequency of 1,250 Hz. These settings were chosen because they represent the mid range of settings N