Measurement of Transverse Relaxation Times and Content Ratio of23Na in Phantoms Simulating Biological Systems by Use of Multiple-Quantum Filtering

✍ Scribed by K.J. Jung; P.J. Cannon; J. Katz

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 158 KB
• Volume: 124
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.1996.1039

✦ Synopsis

Sodium in most biological systems relaxes biexponentially and nentially with fast (R in 2 f and R ex 2 f ) and slow (R in 2s and R ex 2s ) generates a multiple-quantum signal. In a multiple-quantum filtransverse relaxation rates, respectively (4-7). Thus, both tering sequence, the sodium contributing to the multiple-quantum intracellular and extracellular sodium can generate MQ sigsignal is in single-quantum coherences during the preparation and nals through biexponential relaxation, and consequently, acquisition times, while it is in multiple-quantum coherences durshift reagents are still needed in MQ filtering to distinguish ing the evolution time. In contrast to the biexponential relaxation between intracellular and extracellular sodium (6-8). Unof single-quantum coherences, double-and triple-quantum coherfortunately, shift reagents are potentially toxic and, in genences relax monoexponentially during the evolution time with fast eral, themselves alter the relaxation rates. Therefore, a techand slow transverse relaxation rates, respectively. This unique feanique has been sought to distinguish between intracellular ture of multiple-quantum filtering is exploited to measure the and extracellular sodium without using shift reagents (4, 9).

transverse relaxation rates of phantoms simulating intracellular and extracellular sodium by analyzing the double-and triple-quan-

We here exploit the unique characteristics of MQ sodium tum signals acquired at various evolution times. As a byproduct, signals to develop a technique which can permit the measurethe relative ratio of multiple-quantum signals derived from intrament of the transverse relaxation rates for both intracellular cellular and extracellular sodium can also be simultaneously deterand extracellular sodium without the need of shift reagents mined. This technique may enable the distinction between intracel- (10,11). We also demonstrate that with these measurements lular and extracellular sodium content in biological systems withit is possible to determine the relative ratio of the intracelluout using potentially toxic shift reagents. ᭧ 1997 Academic Press lar and extracellular sodium generating MQ signals.

METHODS