Imaging of Heterogeneous Materials with a Turbo Spin Echo Single-Point Imaging Technique

Beyea, Steven; Balcom, Bruce J.; Mastikhin, Igor V.; Bremner, T. W.; Armstrong, Robin L.; Grattan-Bellew, P.E.

doi:10.1006/jmre.2000.2054

Cited by 54 publications

(28 citation statements)

References 53 publications

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“…Similarly, the use of 1 H MRI to map the immobile leaf constituents in tobacco filler inside cigarettes requires special 1 H pulse methods developed specifically for imaging solid materials. Single-point imaging (SPI) [4][5][6][7] and single-point ramped imaging with T 1 enhancement (SPRITE) [8][9][10][11][12][13] are two methods that meet this requirement [1].…”

Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging characterization of intact smoked cigarettes

Axelson¹,

Wooten²

2007

Journal of Analytical and Applied Pyrolysis

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Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging characterization of intact smoked cigarettes

Axelson¹,

Wooten²

2007

Journal of Analytical and Applied Pyrolysis

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“…76 This technique, known as single point imaging (SPI) (also referenced as constant time imaging, CTI), has been widely applied, in different modified forms, to solid-state NMR imaging. [77][78][79][80] The sensitivity and resolution of SPI have been well explored in a pioneering paper by Gravina and Cory. 81 The method essentially consists of generating k-space information in the presence of pure phase-encoding static gradients and is shown to provide artifact free images, because it does not measure the time evolution of the magnetization.…”

Section: Single Point Imagingmentioning

confidence: 99%

Radio frequency continuous‐wave and time‐domain EPR imaging and Overhauser‐enhanced magnetic resonance imaging of small animals: instrumental developments and comparison of relative merits for functional imaging

et al. 2004

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Electron paramagnetic resonance (EPR) imaging in the continuous wave (CW) and time-domain modes, as well as Overhauser-enhanced magnetic resonance imaging in vivo is described. The review is based mainly on the CW and time-domain EPR instrumentation at 300 MHz developed in our laboratory, and the relative merits of these methods for functional in vivo imaging of small animals to assess hypoxia and tissue redox status are described. Overhauser imaging of small animals at magnetic fields in the range 10-15 mT that is being carried out in our laboratory for tumor imaging and the evaluation of tumor hypoxia based on quantitative evaluation of Overhauser enhancement is also described. Alternate approaches to spectral-spatial imaging using the transverse decay constants to infer in situ line widths and hence in vivo pO 2 using CW and time-domain EPR imaging are also discussed. The nature of the spin probes used, the quality of the images obtained in all the three methods, the achievable resolution, limitations and possible future directions in small animal functional imaging with these modalities are summarized.

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“…In the present work the SE-SPI and turbo SE-SPI methods [9] are modified to create a new imaging technique, termed hybrid SE-SPI. The k-space origin data point is acquired with a near zero evolution time from the FID following the 90°excitation pulse.…”

Section: Introductionmentioning

confidence: 99%

Spin echo SPI methods for quantitative analysis of fluids in porous media

Li¹,

Han²,

Balcom³

2009

Journal of Magnetic Resonance

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Fluid density imaging is highly desirable in a wide variety of porous media measurements. The SPRITE class of MRI methods has proven to be robust and general in their ability to generate density images in porous media, however the short encoding times required, with correspondingly high magnetic field gradient strengths and filter widths, and low flip angle RF pulses, yield sub-optimal S/N images, especially at low static field strength. This paper explores two implementations of pure phase encode spin echo 1D imaging, with application to a proposed new petroleum reservoir core analysis measurement. In the first implementation of the pulse sequence, we modify the spin echo single point imaging (SE-SPI) technique to acquire the k-space origin data point, with a near zero evolution time, from the free induction decay (FID) following a 90 degrees excitation pulse. Subsequent k-space data points are acquired by separately phase encoding individual echoes in a multi-echo acquisition. T(2) attenuation of the echo train yields an image convolution which causes blurring. The T(2) blur effect is moderate for porous media with T(2) lifetime distributions longer than 5 ms. As a robust, high S/N, and fast 1D imaging method, this method will be highly complementary to SPRITE techniques for the quantitative analysis of fluid content in porous media. In the second implementation of the SE-SPI pulse sequence, modification of the basic measurement permits fast determination of spatially resolved T(2) distributions in porous media through separately phase encoding each echo in a multi-echo CPMG pulse train. An individual T(2) weighted image may be acquired from each echo. The echo time (TE) of each T(2) weighted image may be reduced to 500 micros or less. These profiles can be fit to extract a T(2) distribution from each pixel employing a variety of standard inverse Laplace transform methods. Fluid content 1D images are produced as an essential by product of determining the spatially resolved T(2) distribution. These 1D images do not suffer from a T(2) related blurring. The above SE-SPI measurements are combined to generate 1D images of the local saturation and T(2) distribution as a function of saturation, upon centrifugation of petroleum reservoir core samples. The logarithm mean T(2) is observed to shift linearly with water saturation. This new reservoir core analysis measurement may provide a valuable calibration of the Coates equation for irreducible water saturation, which has been widely implemented in NMR well logging measurements.

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Imaging of Heterogeneous Materials with a Turbo Spin Echo Single-Point Imaging Technique

Cited by 54 publications

References 53 publications

Magnetic resonance imaging characterization of intact smoked cigarettes

Magnetic resonance imaging characterization of intact smoked cigarettes

Radio frequency continuous‐wave and time‐domain EPR imaging and Overhauser‐enhanced magnetic resonance imaging of small animals: instrumental developments and comparison of relative merits for functional imaging

Spin echo SPI methods for quantitative analysis of fluids in porous media

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