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Three‐dimensional triple‐quantum‐filtered 23 Na imaging of the dog head in vivo
Author(s) -
Kalyanapuram Roopa,
Seshan Viswanathan,
Bansal Navin
Publication year - 1998
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880080527
Subject(s) - imaging phantom , pulse (music) , pulse sequence , nuclear magnetic resonance , physics , signal (programming language) , computer science , optics , detector , programming language
Multiple‐quantum (MQ)‐filtered 23 Na NMR has been proposed as a means to partially discriminate between intracellular and extracellular sodium. However, low signal‐to‐noise ratio (SNR) has been a major obstacle to MQ‐filtered 23 Na imaging becoming an important technique for biological and clinical applications. We compared the various MQ‐filtered 23 Na imaging pulse sequences to select the optimum sequence that provides the best SNR. The results of phantom experiments show that the gradient‐echo MQ‐filtered 23 Na imaging sequence produces the best SNR. We also report, for the first time, three‐dimensional single‐quantum (SQ) and triple‐quantum (TQ)‐filtered 23 Na images of the live dog brain and demonstrate the sensitivity of these images to ischemia produced by euthanizing the animal. The SQ images showed a 10% to 15% decrease in signal intensity from the brain postmortem, whereas the TQ‐filtered images showed a 40% to 50% increase. These changes in signal intensities are consistent with the influx of Na + into the cells upon death. The feasibility of obtaining TQ‐filtered 23 Na images of in situ dog brain encourages us to apply this technique to humans.