Numerical solutions to the time-dependent Bloch equations revisited

Murase, Kenya; Tanki, Nobuyoshi

doi:10.1016/j.mri.2010.07.003

Cited by 78 publications

(86 citation statements)

References 19 publications

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“…A and B in Figure 1 represent the pools of bulk water protons and labile solute protons, respectively. The time-dependent Bloch-McConnell equations for the two-pool chemical exchange model in CEST or APT MRI are expressed as [17,18]. …”

Section: Two-pool Chemical Exchange Modelmentioning

confidence: 99%

“…The CEST effect has usually been analyzed using the so-called Z-spectrum [18]. The Z-spectrum is given by the following equation:…”

Section: Calculation Of Z-spectrum Mtr Asym and Ptrmentioning

confidence: 99%

“…The magnetization transfer asymmetry (MTR asym ) analysis has been performed using the following equation [18]:…”

Section: Calculation Of Z-spectrum Mtr Asym and Ptrmentioning

confidence: 99%

“…Instead of MTR asym , the following equation for proton transfer ratio (PTR) has also been used for analyzing the CEST effect [18]:…”

Section: Calculation Of Z-spectrum Mtr Asym and Ptrmentioning

confidence: 99%

“…When there are multiple exchangeable pools within a single CEST system, the contrast mechanism of CEST becomes all the more complex [16]. Numerical simulations are useful and effective for analyzing the complex CEST contrast mechanism and for investigating the optimal imaging parameter values [17,18]. In order to perform extensive numerical simulations for CEST or APT MRI, it requires the development of a simple and fast numerical method for obtaining the solutions to the time-dependent Bloch-McConnell equations.…”

Section: Introductionmentioning

confidence: 99%

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Basics of Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging

Murase¹

2018

High-Resolution Neuroimaging - Basic Physical Principles and Clinical Applications

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Chemical exchange saturation transfer (CEST) is one of the contrast mechanisms in magnetic resonance imaging (MRI) and has been used to detect dilute proteins through the interaction between bulk water and labile solute protons. Amide proton transfer (APT) MRI has been developed for imaging diseases such as acute stroke. Moreover, various CEST agents have been explored to enhance the CEST effect. The contrast mechanism of CEST or APT MRI, however, is complex and depends not only on the concentration of amide protons or CEST agents and exchange properties, but also varies with imaging parameters such as radiofrequency (RF) power and magnetic field strength. When there are multiple exchangeable pools within a single CEST system, the contrast mechanism of CEST becomes even more complex. Numerical simulations are useful and effective for analyzing the complex contrast mechanism of CEST and for investigating the optimal imaging parameter values. In this chapter, we present the basics of CEST or APT MRI and a simple and fast numerical method for solving the time-dependent Bloch-McConnell equations for analyzing the behavior of magnetization and/or contrast mechanism in CEST or APT MRI. We also present a method for analyzing the behavior of magnetization in spin-locking CEST MRI.

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Section: Two-pool Chemical Exchange Modelmentioning

confidence: 99%

“…The CEST effect has usually been analyzed using the so-called Z-spectrum [18]. The Z-spectrum is given by the following equation:…”

Section: Calculation Of Z-spectrum Mtr Asym and Ptrmentioning

confidence: 99%

“…The magnetization transfer asymmetry (MTR asym ) analysis has been performed using the following equation [18]:…”

Section: Calculation Of Z-spectrum Mtr Asym and Ptrmentioning

confidence: 99%

“…Instead of MTR asym , the following equation for proton transfer ratio (PTR) has also been used for analyzing the CEST effect [18]:…”

Section: Calculation Of Z-spectrum Mtr Asym and Ptrmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Basics of Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging

Murase¹

2018

High-Resolution Neuroimaging - Basic Physical Principles and Clinical Applications

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Paramagnetic CEST MRI Contrast Agents

Terreno¹,

Castelli²,

Aime³

2013

The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging

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Left ventricular puncture: No frontier is risk free

Block

2010

Cathet Cardio Intervent

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Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is capable of measuring dilute labile protons and microenvironmental properties. However, the CEST contrast is dependent upon experimental conditions—particularly, the radiofrequency (RF) irradiation scheme. Although continuous‐wave RF irradiation has been used conventionally, the limited RF pulse duration or duty cycle of most clinical systems requires the use of pulsed RF irradiation. Here, the conventional numerical simulation is extended to describe pulsed‐CEST MRI contrast as a function of RF pulse parameters (i.e., RF pulse duration and flip angle) and labile proton properties (i.e., exchange rate and chemical shift). For diamagnetic CEST agents undergoing slow or intermediate chemical exchange, simulation shows a linear regression relationship between the optimal mean RF power of pulsed‐CEST MRI and continuous‐wave‐CEST MRI. The optimized pulsed‐CEST contrast is approximately equal to that of continuous‐wave‐CEST MRI for exchange rates less than 50 s−1, as confirmed experimentally using a multicompartment pH phantom. In the acute stroke animals, we showed that pulsed‐ and continuous‐wave‐amide proton CEST MRI demonstrated similar contrast. In summary, our study elucidated the RF irradiation dependence of pulsed‐CEST MRI contrast, providing useful insights to guide its experimental optimization and quantification. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.

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Numerical solutions to the time-dependent Bloch equations revisited

Cited by 78 publications

References 19 publications

Basics of Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging

Basics of Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging

Paramagnetic CEST MRI Contrast Agents

Left ventricular puncture: No frontier is risk free

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