TmDOTP5- as a23Na shift reagent for the subcutaneously implanted 9L gliosarcoma in rats

Abstract

The use of TmDOTP5– as an in vivo 23Na NMR shift reagent (SR) for subcutaneously implanted 9L gliosarcoma was evaluated. TmDOTP5– produced a single sharp extracellular peak after about 50–60 min of infusion, and did not cause any changes in the 31P resonance areas or chemical shifts, suggesting that the SR is homogeneously distributed in the extracellular space and does not alter tumor bioenergetic status. TmDOTP5– and CoEDTA– as extracellular space markers gave identical results for relative extracellular space (0.25 ± 0.03 and 0.25 ± 0.04, respectively) and intracellular Na+ concentration (19.3 ± 4.0 mM and 18.6 ± 3.9 mM, respectively), indicating that the biodistribution of the SR is the same as the well‐accepted extracellular space marker. The in vivo T1 and T2 relaxation times of intra‐ and extracellular Na+ were also measured. Our results indicate that TmDOTP5– promises to be an effective shift reagent and extracellular space marker in the 9L gliosarcoma and perhaps other tumors. Magn Reson Med 45:436–442, 2001. © 2001 Wiley‐Liss, Inc.

Acute changes in extracellular volume fraction in skeletal muscle monitored by23Na NMR spectroscopy

“…Monoexponential T 1 recovery and biexponential ${\mathrm{T}}_2^{\ast }$ decay behaviors were observed in the calf muscle tissues. This corresponds to what is generally observed in the skeletal muscle (Winter and Bansal 2001), and is explained by a two‐component model in fast‐exchange regime with a pool of Na + ions within bulk isotropic medium and a pool of Na + ions bound to macromolecules experiencing quadrupolar interactions. Global 23 Na T 1 relaxation times were significantly increased during vascular filling but this parameter did not allow to differentiate between vascular draining and control conditions.…”

Regional and temporal variations in tissue sodium concentration during the acute stroke phase

“…Using this technique, a TE of 853 ms was achieved, which helped to minimize T 2 -weighting effects on the measured signal intensity. T 1 -weighting effects were also minimized by a relatively long TR of 200 ms, considering the T 1 for 23 Na in vivo to be in the region of 40 ms (17,18). Details of the acquisition parameters are presented in Table 1.…”

How can sodium MRI techniques help us understand acute stroke?

“…The first involves the use of shift reagents such as TmDOTP(5-), first introduced in 2001 (62) . However, all such reagents are highly toxic to humans and it remains to be seen whether non-toxic variants can be developed.…”