title: MR-based in vivo follow-up study of Achilles tendon volume and hydration state after ankle-loading activity.
abstract: The purpose of this study was to evaluate temporal alterations of the Achilles tendon volume and hydration state after cross-country-running. Achilles tendons of six untrained participants were examined on a 3T MR-scanner before running, immediately afterwards, and in the following 24, 48, and 72 h. Using a 3D-UTE sequence, caudal (CA) and cranial (CR) mid-portion tendon areas were examined with off-resonance saturation ratios (OSR) and T2* relaxation times. Tendon volume was measured with a self-written Matlab-based automated contour detection algorithm (AVAT) in submillimeter T2-weighted MR images. A significant influence of running in caudal (P = 0.017) and cranial OSR values (P = 0.001), tendon volume (P = 0.024), and cranial T2* measurements (P = 0.046), but not in caudal T2* values (P = 0.298) were found. In detail, mean individual OSR and tendon volume measurements demonstrated a similar but inverted course in their values after exercise: initially, OSR values increased after running (and tendon volume decreased), while subsequently a decrease of OSR values (with an increase of tendon volume) could be observed. OSR and tendon volume measurements are able to detect a physiological response of tendons to a mechanical stimulus. After a transient decrease of free water in the Achilles tendon, an increase with a maximum free water content 48 h after ankle loading and a tendency toward normalization after 72 h was found.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.|Department of Radiology, University Hospital Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: U
authors.initials: U
authors.lastname: Grosse
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany. roland.syha@med.uni-tuebingen.de.
authors.forename: R
authors.initials: R
authors.lastname: Syha
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Gatidis
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Grözinger
authors.affiliation: Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Martirosian
authors.affiliation: Department of Radiology, University Hospital Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: S
authors.initials: S
authors.lastname: Partovi
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Nikolaou
authors.affiliation: Department of Radiology, University Hospital Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Robbin
authors.affiliation: Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Schick
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany.|Musculoskeletal Centre X-Ray Department, Chapel Allerton Hospital, Leeds, UK.
authors.forename: F
authors.initials: F
authors.lastname: Springer
mesh_terms: D000125:Achilles Tendon / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000378:metabolism*; D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009929:Organ Size; D012420:Running / Q000502:physiology*; D013997:Time Factors; D014867:Water / Q000378:metabolism; D016474:Weight-Bearing / Q000502:physiology*
chemical_list: D014867:Water
keywords: Achilles tendon; magnetization transfer; off-resonance saturation ratios; physiological tendon adaptation; ultrashort echo time