2007 Blood oxygen level-dependent MRI in myocardium and skeletal muscle at 1.5 T and 3.0 T

Background

Blood-oxygen level dependent (BOLD) cardiac magnetic resonance imaging (CMR) is a potential diagnostic tool to differentiate ischemic from non-ischemic myocardium.

Methods

T2* values of the myocardial and calf muscle were measured and compared between 1.5 T and 3 T to quantify the respective changes in the tissue T2* property, its dependency on the spatial resolution and to assess the sensitivity of the different field strength for hypoxia. T2* mapping of the calf muscle was performed in 15 volunteers before, during and after no-flow ischemia of the leg. In 23 healthy volunteers T2* maps of the myocardium were generated. Additionally, T2* was measured during adenosine infusion in eight volunteers.

Results

Mean myocardial T2* at 1.5 T was 47.96 ± 10.69 ms and at 3 T 20.44 ± 4.49 ms. After obstruction of the leg the T2* reduction of the calf at 1.5 T was 3.4% (p = 0.001) and 13.0% at 3 T (p < 0.0001). T2* relaxation increased significantly during adenosine at 1.5 T and 3 T (p < 0.0001).

Conclusion

T2* quantification at 1.5 T and 3 T yields a linear relationship. No significant difference could be observed between breath hold and respiratory navigator gated techniques indicating the feasibility of T2* quantification at high spatial resolution. The T2* decrease during hypoxemia of the calf ant the increase during hyperemia of the myocardium indicate that our presented protocol could possibly be applied for evaluation of inducible myocardial ischemia.