W134 AJR:193, August 2009 cal developments, such as for calculation of axial and lateral displacement of tissue struc- tures under compression, allow better spatial resolution, a reduction in artifacts, and in- creased accuracy in using real-time sono- elastography for routine examinations [4]. Using conventional ultrasound, it is some- times difficult or even impossible to dis- tinguish pathologic tissue because it often presents with the same echogenicity as the surrounding healthy tissue [5]. However, it is well known that inflammation and tumors lead to changes in tissue elasticity [5]. Al- though real-time sonoelastography is not yet used in routine clinical practice, it has been shown to be useful in the differential diag- nosis of breast [6, 7], thyroid [8], and pros- tate [4] cancers and recently was applied to lymph node characterization [9]. Estima- tion of tissue elasticity might also be a use- Real-Time Sonoelastography Findings in Healthy Achilles Tendons Tobias De Zordo 1 Christian Fink 2 Gudrun M. Feuchtner 1 Vinzenz Smekal 2 Markus Reindl 3 Andrea Sabine Klauser 1 De Zordo T, Fink C, Feuchtner GM, Smekal V, Reindl M, Klauser AS 1 Department of Radiology II, Medical University Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria. Address correspondence to A. S. Klauser (andrea.klauser@i-med.ac.at). 2 Department of Trauma Surgery and Sports Medicine, Medical University Innsbruck, Innsbruck, Austria. 3 Department of Neurology, Medical University Innsbruck, Innsbruck, Austria. Musculoskeletal฀Imaging฀•฀Original฀Research WEB This is a Web exclusive article. AJR 2009; 193:W134–W138 0361–803X/09/1932–W134 © American Roentgen Ray Society R eal-time sonoelastography is a new ultrasound-based technique able to assess tissue elasticity [1]. Ophir et al. [2] first described the principle of strain imaging (“elastogra- phy”) in 1991; in 1999, Pesavento et al. [3] developed a fast cross-sectional technique based on real-time elastography to allow its use in clinical practice. The principle of real- time sonoelastography is as follows: Tissue compression produces displacement within the tissue, which is less in hard tissue than in soft tissue. Real-time sonoelastography can show different degrees of displacement by comparing image pairs before and after com- pression is applied on tissue [2, 3]. Tissue displacement is calculated in real time by an ultrasound scanner modified so different grades of elasticity can be displayed over a conventional ultrasound image. New techni- Keywords: Achilles tendon, elastography, sonoelastography, sports medicine, tendinosis, ultrasound DOI:10.2214/AJR.08.1843 Received September 18, 2008; accepted after revision November 24, 2008. OBJECTIVE. Real-time sonoelastography is a new ultrasound-based technique able to assess tissue elasticity that has already shown feasibility in tumor diagnosis. The aim of this study was to assess the performance of real-time sonoelastography in depicting the Achilles tendons of healthy volunteers and to compare sonoelastography findings with conventional ultrasound findings. MATERIALS฀AND฀METHODS. Eighty asymptomatic Achilles tendons of 40 healthy volunteers (19 men, 21 women; mean age, 38 years; range, 20–76 years) were examined on real-time sonoelastography and ultrasound. The Achilles tendons were divided into the fol- lowing thirds for image evaluation: proximal (musculotendinous junction), middle (2–6 cm above insertion at the calcaneus), and distal (insertion at the calcaneus). Longitudinal and axial images of each tendon third were obtained using ultrasound and real-time sonoelastog- raphy. Real-time sonoelastography images were evaluated by reviewers using an experimen- tally proven color grading system. RESULTS. The Achilles tendons showed mainly a hard structured pattern (86.7%) (208/240 tendon thirds) on sonoelastography; however, mild softening was found in 12.1% (29/240) of the tendons. Distinct softening corresponding to alterations found also on ultra- sound and, therefore, suggesting subclinical changes was detected in 1.3% (3/240). The over- all correlation (κ) between real-time sonoelastography and ultrasound findings was 1.00. CONCLUSION. In healthy volunteers, the Achilles tendon appeared hard on real-time sonoelastography with excellent correlation to ultrasound. Further investigation including pathologic tendons should be performed to prove the value of real-time sonoelastography in the assessment of Achilles tendinopathy. De Zordo et al. Sonoelastography of Healthy Achilles Tendons Musculoskeletal Imaging Original Research Downloaded from www.ajronline.org by 52.73.204.196 on 05/17/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved