title: T2*-weighted and arterial spin labeling MRI of calf muscles in healthy volunteers and patients with chronic exertional compartment syndrome: preliminary experience.
abstract: OBJECTIVE
  The purpose of our study was to assess temporal changes with exercise in T2* and arterial spin labeling signals in patients with chronic exertional compartment syndrome of the anterior compartment of the lower leg and in control subjects using T2* mapping and arterial spin labeling MRI.
  
  
  METHODS
  This prospective study was approved by the institutional research ethics board. Ten control subjects (five women and five men; mean age, 29.0 years) and nine patients with chronic exertional compartment syndrome (three women and six men; mean age, 33.7 years) gave informed written consent and underwent MRI of the calf muscles using an axial T2*-weighted multiecho gradient-recalled echo and a flow-sensitive alternating inversion recovery sequence with echo-planar imaging readouts before (baseline) and 3, 6, 9, 12, and 15 minutes after exercise. T2* and arterial spin labeling signal changes (DeltaT2* and DeltaASL, respectively) over time were calculated relative to the baseline examination. DeltaT2* and DeltaASL between patients and control subjects were compared using the Student's t test.
  
  
  RESULTS
  In both patients and control subjects, DeltaT2* and DeltaASL showed a peak at 3 minutes after exercise, followed by a decrease over time. The maximum DeltaT2* was 26% and 29% for patients and control subjects, respectively. The maximum DeltaASL was 183% and 224% for patients and control subjects, respectively. After 15 minutes, arterial spin labeling signal returned to baseline; however, T2* remained elevated (8% in patients; 10% in control subjects). No statistically significant differences between patients and control subjects in postexercise DeltaT2* and DeltaASL were found (p = 0.21-0.98).
  
  
  CONCLUSIONS
  After calf muscle exercise, no statistically significant differences in T2* relaxation times or arterial spin labeling signal, indicative of differences in muscle oxygenation and perfusion status, were found between patients with chronic exertional compartment syndrome and control subjects.
authors.affiliation: Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, Toronto, ON, Canada.
authors.forename: Gustav
authors.initials: G
authors.lastname: Andreisek
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: White
authors.forename: Marshall S
authors.initials: MS
authors.lastname: Sussman
authors.forename: Deanna L
authors.initials: DL
authors.lastname: Langer
authors.forename: Chirag
authors.initials: C
authors.lastname: Patel
authors.forename: Jason Wen-Shyang
authors.initials: JW
authors.lastname: Su
authors.forename: Masoom A
authors.initials: MA
authors.lastname: Haider
authors.forename: Jeff A
authors.initials: JA
authors.lastname: Stainsby
mesh_terms: D000328:Adult; D000868:Anterior Compartment Syndrome / Q000175:diagnosis*; D002908:Chronic Disease; D012090:Cumulative Trauma Disorders / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007866:Leg / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D005082:Physical Exertion; D010865:Pilot Projects; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels