Chlorine and sodium chemical shift imaging during acute stroke in a rat model at 9.4 Tesla.

Object: A triple-resonant coil setup with an (1)H linear resonator and a double-tuned (23)Na/(35)Cl surface coil was used to study the evolution of T 2 (*) and M 0 for (35)Cl and (23)Na in a rat stroke model during the acute phase at 9.4 Tesla.

Materials And Methods: In vivo measurements were performed 1.5-7 h after onset of stroke (n = 2), ten days after onset (n = 1) and on a healthy control rat by a chemical shift imaging sequence. Measurement times were 15 min ((23)Na) and 57 min ((35)Cl).

Results: The relaxation times ten days after onset [T 2 (*) = 14.3 ± 1.8 ms ((23)Na) and 6.0 ± 1.3 ms ((35)Cl)] are clearly prolonged in comparison to a healthy rat [T 2 (*) = 4.8 ± 0.6 ms ((23)Na) and 2.1 ± 0.3 ms ((35)Cl)] and the acute phase [T 2 (*) = 5.6 ± 0.2 ms ((23)Na) and 1.9 ± 0.1 ms ((35)Cl)].

Conclusion: M 0 in the infarcted region clearly rises later and slower for chlorine than for sodium. To the best of our knowledge, these are the first combined proton, sodium, and chlorine measurements in an animal stroke model during the acute phase.