title: Intratendinous alterations as imaged by ultrasound and contrast medium-enhanced magnetic resonance in chronic achillodynia.
abstract: OBJECTIVE
  We performed a comparative study of ultrasonography and gadolinium imaging contrast-enhanced T1-weighted magnetic resonance to evaluate tendon pathology in chronic Achilles tendon disorder. Another main issue was to evaluate the structural basis as defined by histopathology from hypoechoic compared with normoechoic areas within the same tendon.
  
  
  METHODS
  Twenty patients (16 male, 4 females, median age 40 years) with chronic achillodynia participated in the study. Clinical examination revealed swelling and tenderness localized to the midportion of the Achilles tendon. Contrast medium-enhanced magnetic resonance imaging (CME-MRI) was performed in all patients. Ultrasonography-guided core biopsies were taken from regions with a clear widening of the tendon and a pathologic low-echo signal as well as from normoechoic areas. The specimens were analyzed with a standardized protocol giving a total tendon score (0-24), and a stereologic method for quantification of glycosaminoglycan (GAG)-rich areas.
  
  
  RESULTS
  The volume of the intratendinous abnormality was larger in 13 of 20 when imaged by CME-MR (P < 0.05), whereas the shape and enlargement of the tendon per se were similarly imaged by ultrasound (US) and CME-MR. Tendon pathology as imaged by US was graded as severe from hypoechoic regions and moderate from normoechoic regions. The corresponding quantification of GAGs was 0.36 compared with 0.17, respectively (P < 0.001).
  
  
  CONCLUSIONS
  CME-MR imaging revealed greater sensitivity in demonstrating intratendinous pathology than the ultrasound; this was documented by the larger size of the corresponding lesion and the fact that the pathology was occurring in areas that were considered normal by ultrasonography. US hypoechoic areas showed a markedly abnormal tendon structure including an increased amount of GAG-rich areas. However, moderate pathology was also found in the neighboring normoechogenous areas within the same tendon, indicating a more generalized disorder than depicted by echogenic properties.
authors.affiliation: Department of Orthopedic Surgery, Huddinge University Hospital, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Movin
authors.forename: M
authors.initials: M
authors.lastname: Kristoffersen-Wiberg
authors.forename: A
authors.initials: A
authors.lastname: Shalabi
authors.forename: A
authors.initials: A
authors.lastname: Gad
authors.forename: P
authors.initials: P
authors.lastname: Aspelin
authors.forename: C
authors.initials: C
authors.lastname: Rolf
mesh_terms: D000125:Achilles Tendon / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D000368:Aged; D001706:Biopsy; D002908:Chronic Disease; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000000981:diagnostic imaging* / Q000473:pathology*; D012680:Sensitivity and Specificity; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D005682:Gadolinium