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Relationship between sodium intensity and perfusion deficits in acute ischemic stroke

Authors


Abstract

Purpose

To assess the relationship between sodium signal intensity changes and oligemia, measured with perfusion-weighted imaging (PWI), in ischemic stroke patients.

Materials and Methods

Nine ischemic stroke patients (55 ± 13 years), four with follow-up scans, underwent sodium and proton imaging 4–32 hours after symptom onset. Relative sodium intensity was calculated as the ratio of signal intensities in core (identified as hypertintense lesions on diffusion-weighted imaging [DWI]) or putative penumbra (PWI-DWI mismatch) to contralateral homologous regions.

Results

Sodium intensity increases in the core were not correlated with the severity of hypoperfusion, measured with either cerebral blood flow (rho = 0.157; P = 0.61) or cerebral blood volume (rho = −0.234; P = 0.44). In contrast, relative sodium intensity was not elevated (4–7 hours 0.96 ± 0.07; 17–32 hours 1.00 ± 0.07) in PWI-DWI mismatch regions.

Conclusion

Sodium signal intensity cannot be predicted by the degree of hypoperfusion acutely. Sodium intensity also remains unchanged in PWI-DWI mismatch tissue, indicating preservation of ionic homeostasis. Sodium magnetic resonance imaging (MRI), in conjunction with PWI and DWI, may permit identification of patients with viable tissue, despite an unknown symptom onset time. J. Magn. Reson. Imaging 2011;33:41–47. © 2010 Wiley-Liss, Inc.

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