Use of angulation in the detection of tendinitis with US

The purpose of the study was to examine the possible benefit of the longitudinal probe angle deviation in the detection of tendinitis. The influence of the ultrasound beam angle in longitudinal view on the echo intensity was studied on a bovine tendon in vitro, and in vivo on symptomatic human Achilles tendons, one of which was operated on the following day. Five other consecutive patients with clinically unilateral tendinitis in the Achilles tendon, were treated conservatively. Experimental tendinitis was induced in the bovine tendon by injecting saline water inside the tendon with subsequent swelling of the tendon and separation of the collagen bundles, thus disrupting the anisotropic intratendinous structure. The echogenicity of the intact and injected bovine tendons was studied perpendicularly and with slight angulation of 7-10 degrees. The symptomatic Achilles tendons were studied in a similar way using the asymptomatic tendon as comparison. For in vivo studies, the asymptomatic tendons were used as comparison in clinical and sonographic studies. When increasing the longitudinal probe angle up to 7-10 degrees the normal tendons became hypoechoic, but tendinitic tendons did not lose their echogenicity as rapidly. Moreover the anterior peritenon was seen more clearly in tendinitic tendons compared to the normal side. The method is very useful especially in diagnosing early stage tendinitis, where the treatment should be more effective than in more severe and chronic stages.