Ultrasound with a shear-wave elastography (SWE) technique offers an effective way to evaluate Achilles tendon health in both athletes and nonathletes, according to a study published online January 14 in Academic Radiology.
Studies have demonstrated that SWE is useful for evaluating tendon stiffness and can aid radiologists in diagnosing tendinopathy better than other ultrasound modes, as diseased or injured tendons are generally softer than healthy ones, wrote a team led by Dr. Timm Dirrichs of RWTH Aachen University Hospital in Germany. But reference data from varying population groups are lacking.
"[Our main] objective ... was to analyze tendon stiffness in semiprofessional long- and middistance running athletes and to compare [their] tendon stiffness to a nonathletic control group," the group wrote. "[The] second objective was to evaluate the specificity with which SWE was able to predict the absence of clinical symptoms."
Tendons are currently imaged primarily with B-mode ultrasound, power Doppler ultrasound, and MRI. But these methods do not always accurately visualize tendinopathy -- or help clinicians track the transition from asymptomatic to symptomatic disease, according to the researchers.
"In up to 59% of asymptomatic patients, especially athletes, abnormal imaging is present in various tendons, while ... B-mode ultrasound and power Doppler ultrasound might remain inconspicuous in patients with clinical relevant tendinopathy," they noted.
That's where SWE comes in, the researchers wrote. It provides quantitative information about tissue stiffness and, therefore, about the mechanical properties of a tendon, which could be used to estimate tendon integrity.
The study included 68 asymptomatic healthy participants: 33 were semiprofessional athletes who completed at least five training sessions of running per week, and 35 were nonathletic individuals. Each participant's Achilles tendons were imaged with B-mode ultrasound, power Doppler ultrasound, and SWE (136 tendons). SWE values were expressed in kilopascals (kPa).
The mean SWE value for the Achilles tendon was 183.8 kPa in athletes and 103.6 kPa in nonathletes, a difference that was statistically significant (p < 0.001).
"We found athletes' Achilles tendons to be 1.8 times as hard as nonathletes' tendons obtained by SWE," the group noted. "This phenomenon may be caused by repeated training effects."
The researchers found that SWE outperformed both B-mode and power Doppler ultrasound in terms of the specificity of classifying an asymptomatic tendon as healthy:
- B-mode ultrasound: 60.6%
- Power Doppler ultrasound: 93.9%
- SWE: 96.3%
SWE is useful for measuring and displaying the effects of training on the Achilles tendons of athletes, and its high specificity could help clinicians better care for patients, the group wrote.
"[SWE] ... has a high specificity to predict absence of clinical symptoms," Dirrichs and colleagues concluded. "This might be of great clinical interest, especially in asymptomatic athletes, where the rate of false-positive findings in conventional B-mode ultrasound and power Doppler ultrasound is high."
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
