T2*-Weighted and Arterial Spin Labeling MRI of Calf Muscles in Healthy Volunteers and Patients With Chronic Exertional Compartment Syndrome: Preliminary Experience

Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, Toronto, ON, Canada.
American Journal of Roentgenology (Impact Factor: 2.74). 10/2009; 193(4):W327-33. DOI: 10.2214/AJR.08.1579
Source: PubMed

ABSTRACT 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.
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.
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).
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.

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