Analysis of echotexture of tendons with US.

Abstract

To evaluate changes in echotexture of normal tendons at different frequencies and establish an anatomic correlation for fibrillar echoes, normal calcaneal tendons were examined in vitro at 7.5, 10, 13, and 15 MHz in calves (n = 8) and sheep (n = 6) and in vivo in humans (n = 8). Histologic correlation was obtained in vitro with 22-gauge needles that marked the position of echogenic fibrils under ultrasound (US) guidance. The human study group consisted of 25 patients with a clinical diagnosis of calcaneal tendon disease and 15 patients who underwent surgery for rupture of the Achilles tendon. At all four frequencies, normal tendons showed an internal network of fine parallel and linear fibrillar echoes that became more numerous and thinner as US frequency increased. These echoes were caused by specular reflections at the interface between collagen bundles and endotendineum septa. In patients, tendons showed a variety of basic changes in fibrillar pattern: increased fibrillar thickness (33 patients), interruption (17 patients), fragmentation (12 patients), and disappearance of echotexture (15 patients). It is concluded that US holds promise in detection of minimal changes in tendinous structure.

Sonography of chronic Achilles tendinopathy: A case–control study

“…The collagenous bundles are separated by connective tissue septa (endotenon) continuous with the outer connective sheath (peritenon). 7 Vessels run within the endotenon. 18 Overall vascularity of the normal tendon is poor, with the middle third of the tendon being almost avascular.…”

“…19 The sonographic fibrillar echotexture results from the large endotenon septa. 7 The normal Achilles tendon usually has a flat or concave anterior margin. 20 Our study confirms previous studies by showing that the tendon decreases in antero-posterior diameter and widens at the calcaneal insertion in normal subjects 21 and that there is significant positive correlation between tendon thickness and body height.…”

“…2 Sonography is commonly used to evaluate the Achilles tendon and paratendinous structures (subcutaneous tissues, Kager's fat pad [or preAchilles fat pad], bursae, calcaneal insertion, and plantar fascia). Although some features relating to chronic Achilles tendinopathy have been described previously, [7][8][9][10][11][12][13] there are no established sonographic diagnostic criteria for this entity. The purpose of our study was to analyze the sonographic appearances of Achilles tendon in normal subjects and in patients with chronic Achilles tendinopathy with the aim of establishing diagnostic sonographic criteria for chronic Achilles tendinopathy.…”

How does a cadaver model work for testing ultrasound diagnostic capability for rheumatic-like tendon damage?

“…The group has worked on validation of US-detected and graded tendon damage in RA [19,20], which is an essential component of the structural damage in this disease [19,20]. This comes in the wake of proven US capability in the diagnosis of superficial tendon lesions, as shown in a number of studies [5][6][7][8][9][10][11][12][13], most using surgical findings [6][7][8] or cadaver models [9,11,12] as criterion standard. In particular, concurrent validity of US in detecting hand tendon tears in RA was shown using surgical findings as criterion standard [8].…”

“…Over the last decades, musculoskeletal (MS) ultrasound (US) has been successfully validated for the diagnosis of tendon injuries at the wrist/hand and ankle/foot [5][6][7][8][9][10][11][12][13], with an accuracy comparable to that of magnetic resonance imaging (MRI) [6,8,10,11]. Both imaging techniques are especially useful in the detection of partial tendon tears, which are much more challenging to diagnose by clinical assessment than complete tears [8].…”