title: Bi-exponential T2 analysis of healthy and diseased Achilles tendons: an in vivo preliminary magnetic resonance study and correlation with clinical score.
abstract: OBJECTIVE
  To compare mono- and bi-exponential T2 analysis in healthy and degenerated Achilles tendons using a recently introduced magnetic resonance variable-echo-time sequence (vTE) for T2 mapping.
  
  
  METHODS
  Ten volunteers and ten patients were included in the study. A variable-echo-time sequence was used with 20 echo times. Images were post-processed with both techniques, mono- and bi-exponential [T2 m, short T2 component (T2 s) and long T2 component (T2 l)]. The number of mono- and bi-exponentially decaying pixels in each region of interest was expressed as a ratio (B/M). Patients were clinically assessed with the Achilles Tendon Rupture Score (ATRS), and these values were correlated with the T2 values.
  
  
  RESULTS
  The means for both T2 m and T2 s were statistically significantly different between patients and volunteers; however, for T2 s, the P value was lower. In patients, the Pearson correlation coefficient between ATRS and T2 s was -0.816 (P = 0.007).
  
  
  CONCLUSIONS
  The proposed variable-echo-time sequence can be successfully used as an alternative method to UTE sequences with some added benefits, such as a short imaging time along with relatively high resolution and minimised blurring artefacts, and minimised susceptibility artefacts and chemical shift artefacts. Bi-exponential T2 calculation is superior to mono-exponential in terms of statistical significance for the diagnosis of Achilles tendinopathy.
  
  
  CONCLUSIONS
  • Magnetic resonance imaging offers new insight into healthy and diseased Achilles tendons • Bi-exponential T2 calculation in Achilles tendons is more beneficial than mono-exponential • A short T2 component correlates strongly with clinical score • Variable echo time sequences successfully used instead of ultrashort echo time sequences.
authors.affiliation: Center of Excellence for High field MR, Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria, vladimir.juras@meduniwien.ac.at.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Juras
authors.forename: Sebastian
authors.initials: S
authors.lastname: Apprich
authors.forename: Pavol
authors.initials: P
authors.lastname: Szomolanyi
authors.forename: Oliver
authors.initials: O
authors.lastname: Bieri
authors.forename: Xeni
authors.initials: X
authors.lastname: Deligianni
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
mesh_terms: D000125:Achilles Tendon / Q000473:pathology*; D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052256:Tendinopathy / Q000473:pathology*