title: Impaired skeletal muscle microcirculation in systemic sclerosis.
abstract: BACKGROUND
  Muscle symptoms in systemic sclerosis (SSc) may originate from altered skeletal muscle microcirculation, which can be investigated by means of blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI).
  
  
  METHODS
  After ethics committee approval and written consent, 11 consecutive SSc patients (5 men, mean age 52.6 years, mean SSc disease duration 5.4 years) and 12 healthy volunteers (4 men, mean age 45.1 years) were included. Subjects with peripheral arterial occlusive disease were excluded. BOLD MRI was performed on calf muscles during cuff-induced ischemia and reactive hyperemia, using a 3-T whole-body scanner (Verio, Siemens, Erlangen, Germany) and fat-suppressed single-short multi-echo echo planar imaging (EPI) with four different effective echo times. Muscle BOLD signal time courses were obtained for gastrocnemius and soleus muscles: minimal hemoglobin oxygen saturation (T2*min) and maximal T2* values (T2*max), time to T2* peak (TTP), and slopes of oxygen normalization after T2* peaking.
  
  
  RESULTS
  The vast majority of SSc patients lacked skeletal muscle atrophy, weakness or serum creatine kinase elevation. Nevertheless, more intense oxygen desaturation during ischemia was observed in calf muscles of SSc patients (mean T2*min -15.0%), compared with controls (-9.1%, P = 0.02). SSc patients also had impaired oxygenation during hyperemia (median T2*max 9.2% vs. 20.1%, respectively, P = 0.007). The slope of muscle oxygen normalization was significantly less steep and prolonged (TTP) in SSc patients (P<0.001 for both). Similar differences were found at a separate analysis of gastrocnemius and soleus muscles, with most pronounced impairment in the gastrocnemius.
  
  
  CONCLUSIONS
  BOLD MRI demonstrates a significant impairment of skeletal muscle microcirculation in SSc.
authors.forename: Sasan
authors.initials: S
authors.lastname: Partovi
authors.forename: Anja-Carina
authors.initials: AC
authors.lastname: Schulte
authors.forename: Markus
authors.initials: M
authors.lastname: Aschwanden
authors.forename: Daniel
authors.initials: D
authors.lastname: Staub
authors.forename: Daniela
authors.initials: D
authors.lastname: Benz
authors.forename: Stephan
authors.initials: S
authors.lastname: Imfeld
authors.forename: Björn
authors.initials: B
authors.lastname: Jacobi
authors.forename: Pavel
authors.initials: P
authors.lastname: Broz
authors.forename: Kurt A
authors.initials: KA
authors.lastname: Jäger
authors.forename: Martin
authors.initials: M
authors.lastname: Takes
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Huegli
authors.forename: Deniz
authors.initials: D
authors.lastname: Bilecen
authors.forename: Ulrich A
authors.initials: UA
authors.lastname: Walker
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000473:pathology / Q000503:physiopathology; D007511:Ischemia / Q000473:pathology / Q000503:physiopathology; D007866:Leg / Q000098:blood supply; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology*; D010100:Oxygen / Q000097:blood; D012595:Scleroderma, Systemic / Q000473:pathology / Q000503:physiopathology*
chemical_list: D010100:Oxygen