Quantitative <i>in vivo</i> tissue sodium concentration maps: The effects of biexponential relaxation

Boada, Fernando E.; Christensen, James; Huang-Hellinger, Frank; Reese, Timothy G.; Thulborn, Keith R.

doi:10.1002/mrm.1910320210

Cited by 65 publications

(54 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Each of these limitations have been addressed in other reports (29)(30)(31). They have not been applied in the current study which was completed before those modifications were available.…”

Section: Discussionmentioning

confidence: 78%

Quantitative tissue sodium concentration mapping of normal rat brain

Christensen

Barrere

Boada

et al. 1996

Magnetic Resonance in Med

Self Cite

104

View full text Add to dashboard Cite

A quantitative in vivo method for obtaining maps of tissue sodium concentration (TSC) by MRI is compared to the invasive, global 22Na radionuclide dilutional technique in the normal rat brain. The MR method uses a three-dimensional projectional acquisition scheme to minimize signal losses from transverse relaxation. Internal calibration standards are used to convert the signal intensity into TSC after correction for B1 inhomogeneities by using the ratio of 23Na and 1H images obtained with identical B1 distributions and sensitivities at the two frequencies. Over the biological range of concentrations, the TSC, measured as the ratio of MR signals of 23Na and 1H, gives a linear response with concentration. In the normal rat brain, the mean TSC measured using the MRI method (TSC = 45 +/- 4 mM, animals = 5) is not significantly different from the global 22Na radionuclide method (TSC = 49 +/- 6 mM, animals = 7).

show abstract

“…Each of these limitations have been addressed in other reports (29)(30)(31). They have not been applied in the current study which was completed before those modifications were available.…”

Section: Discussionmentioning

confidence: 78%

Quantitative tissue sodium concentration mapping of normal rat brain

Christensen

Barrere

Boada

et al. 1996

Magnetic Resonance in Med

Self Cite

104

View full text Add to dashboard Cite

show abstract

“…Physiological processes associated with the infraction may result in exchange or redistribution of chloride ions between compartments with very short and long relaxation times, thus giving a contribution to the 35 Cl signal intensity in the MR images which does not depend on the concentration of chloride ions. On the other hand, Boada et al (6) showed that 23 Na MRI pulse sequences with radial k-space acquisition and very short echo time of TE < 0.5 ms provide accurate estimates for the tissue sodium concentration, even if short T 2 components with T 2 $ 2 ms are present. Assuming equal mobility of sodium and chloride ions, theory predicts shorter transverse relaxation times for 35 Cl (34).…”

Section: Resultsmentioning

confidence: 98%

In vivo chlorine‐35, sodium‐23 and proton magnetic resonance imaging of the rat brain

et al. 2010

View full text Add to dashboard Cite

In this study we demonstrate the feasibility of combined chlorine-35, sodium-23 and proton magnetic resonance imaging (MRI) at 9.4 Tesla, and present the first in vivo chlorine-35 images obtained by means of MRI. With the experimental setup used in this study all measurements could be done in one session without changing the setup or moving the subject. The multinuclear measurement requires a total measurement time of 2 h and provides morphological (protons) and physiological (sodium-23, chlorine-35) information in one scanning session. Chlorine-35, sodium-23 and high resolution proton images were acquired from a phantom, a healthy rat and from a rat displaying a focal cerebral infarction. Compared to the healthy tissue a signal enhancement of a factor of 2.2 +/- 0.2 in the chlorine-35 and a factor of 2.9 +/- 0.6 in the sodium-23 images is observed in the areas of infarction. Exemplary unlocalized measurement of the in vivo longitudinal and transversal relaxation time of chlorine-35 in a healthy rat showed multi-exponential behaviour. A biexponential fit revealed a fast and a slow relaxing component with T(1,a) = (1.7 +/- 0.4) ms, T(1,b) = (25.1 +/- 1.4) ms, amplitudes of A = 0.26 +/- 0.02, (1-A) = 0.74 +/- 0.02 and T(2,a) = (1.3 +/- 0.1) ms, T(2,b) = (11.8 +/- 1.1) ms, A = 0.64 +/- 0.02, (1-A) = 0.36 +/- 0.02. Combined proton, sodium-23 and chlorine-35 MRI may provide a new approach for non-invasive studies of ionic regulatory processes under physiological and pathological conditions in vivo.

show abstract

“…In order to detect both T 2 components, as well as for the accurate quantification of the total sodium concentration, imaging techniques with ultra-short echo times of less than 500 µs are required [1,11]. Up to now, only echo times of more than 3 ms have been realised with ECG-triggered gradient echo 23 Na-MRI techniques [12,13].…”

Section: Introductionmentioning

confidence: 99%

ECG-gated 23 Na-MRI of the human heart using a 3D-radial projection technique with ultra-short echo times

Jerec̆ić

Bock

Nielles‐Vallespin

et al. 2004

MAGMA Magnetic Resonance Materials in Physics, Biology and Medi

View full text Add to dashboard Cite

Pathological changes in tissue often manifest themselves in an altered sodium gradient between intra- and extracellular space due to a malfunctioning Na+-K+ pump, resulting in an increase in total sodium concentration in ischaemic regions. Therefore, 23Na-MRI has the potential to non-invasively differentiate viable from non-viable tissue by detecting concentration changes of intra- and extracellular sodium. As the in vivo sodium signal shows a bi-exponential T2 decay, with a short component of less than 1 ms, the accurate quantification of the total sodium content requires imaging techniques with ultra-short echo times (TE) below 0.5 ms. A 3D-radial projection technique has been developed which allows the acquisition of ECG-triggered sodium images of the human heart with a TE of 0.4 ms. With this pulse sequence 23Na-MRI volunteer measurements of the head or the heart were performed in less than 18 min on a 1.5-T clinical scanner with an isotropic resolution of 10 mm3. The signal to noise ratio of the radial projection technique is twofold higher than that of a Cartesian gradient echo pulse sequence (TE = 3.2 ms). Radial 23Na-MRI provides a tool for clinical studies, aiming at the differentiation of viable and non-viable tissue.

show abstract

Quantitative in vivo tissue sodium concentration maps: The effects of biexponential relaxation

Cited by 65 publications

References 12 publications

Quantitative tissue sodium concentration mapping of normal rat brain

Quantitative tissue sodium concentration mapping of normal rat brain

In vivo chlorine‐35, sodium‐23 and proton magnetic resonance imaging of the rat brain

ECG-gated 23 Na-MRI of the human heart using a 3D-radial projection technique with ultra-short echo times

Contact Info

Product

Resources

About