Proton imaging of siloxanes to map tissue oxygenation levels (PISTOL): a tool for quantitative tissue oximetry

Kodibagkar, Vikram D.; Wang, Xianghui; Pacheco-Torres, Jesús; Gulaka, Praveen; Mason, Ralph P.

doi:10.1002/nbm.1279

Cited by 49 publications

(58 citation statements)

References 43 publications

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“…It is being studied for making low-k dielectric materials for the semi-conductor industries by plasma-enhanced chemical vapor deposition (PECVD) (Barni et al 2012). HMDSO has recently been used in quantitative tissue oximetry (Kodibagkar et al 2006;Kodibagkar et al 2008). To our knowledge, HMDSO is highly inert and has not previously been employed as an internal standard or frequency reference for quantitative purposes in conventional NMR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

A 1H NMR method for the estimation of hydrogen content for all petroleum products

et al. 2015

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Background: Hydrogen content is an important parameter for all petroleum products, because the performance of the products for specific application depends on the concentration of hydrogen in it. Further, hydrogen content can be used as a measure for quality control during the production process and assess the quality of the products, which is governed by the catalyst used. Therefore, to get the desired petroleum products like MS and HSD, pilot scale evaluation of different catalysts plays an important role in problem solving during troubleshooting in refineries. During evaluation studies the performance of catalyst depends upon the hydrogen consumption and mass balance in any catalytic process. In order to calculate total hydrogen consumption during production of different petroleum products an effort has been made to develop a universal method based on nuclear magnetic resonance (NMR) technique, that allows estimating hydrogen content in all petroleum fractions, ranging from IBP to 530+°C.

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Section: Introductionmentioning

confidence: 99%

A 1H NMR method for the estimation of hydrogen content for all petroleum products

et al. 2015

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“…A chemical shift selective (CHESS) spin echo sequence was initially employed to locate the HMDSO resonance. The PISTOL sequence used is described in detail in 20 . The PISTOL-LL sequence, developed and tested here, consists of an inversion-recovery Look-Locker sequence with EPI readout.…”

Section: Pistol-ll Oximetry Pulse Sequencementioning

confidence: 99%

“…In proton MRI, PISTOL (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels) 20 is a recently developed 1 H MR oximetry technique that is based on the 1 H relaxometry of hexamethyldisiloxane (HMDSO), which is a 1 H pO 2 reporter molecule 21 . HMDSO is a promising reporter molecule as its spin-lattice relaxation rate R 1 exhibits a linear dependence on the pO 2 in the temperature range 26 -46 o C 21 .…”

Section: Introductionmentioning

confidence: 99%

A rapid Look-Locker imaging sequence for quantitative tissue oximetry

Shankar

Kodibagkar

2015

SPIE Proceedings

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Tissue oximetry studies using magnetic resonance imaging are increasingly contributing to advances in the imaging and treatment of cancer. The non-invasive measurement of tissue oxygenation (pO 2 ) may facilitate a better understanding of the pathophysiology and prognosis of diseases, particularly in the assessment of the extensive hypoxic regions associated with cancerous lesions. The availability of tumor hypoxia maps could help quantify and predict tumor response to intervention and therapy. The PISTOL (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels) oximetry technique maps the T 1 of administered hexamethyldisiloxane (HMDSO), an 1 H NMR pO 2 reporter molecule in about 3 ½ min. This allows us to subsequently monitor static and dynamic changes in the tissue pO 2 (in response to intervention) at various locations due to the linear relationship between 1/T 1 and pO 2 . In this work, an HMDSO-selective Look-Locker imaging sequence with EPI readout has been developed to enable faster PISTOL acquisitions. The new sequence incorporates the fast Look-Locker measurement method to enable T 1 , and hence, pO 2 mapping of HMDSO in under one minute. To demonstrate the application of this pulse sequence in vivo, 50 µL of neat HMDSO was administered to the thigh muscle of a healthy rat (Fischer F344, n=4). Dynamic changes in the mean pO 2 of the thigh muscle were measured using both PISTOL and the developed LL oximetry sequence in response to oxygen challenge and compared. Results demonstrate the efficacy of the new sequence in rapidly mapping the pO 2 changes, leading to advances in fast quantitative 1 H MR oximetry.

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“…Of the popular techniques for measuring pH, including 31 P-NMR spectroscopy, ion-sensitive microelectrodes, positron emission tomography (PET) and magnetic resonance imaging (MRI) [2][3][4][5], fluorescent pH indicator dyes seem to be highly attractive, due to their higher sensitivity and ability for continuous monitoring of rapid kinetic pH changes [6]. The pH response of these dyes in the form of changes in their upper state lifetime [7][8], or their excitation emission spectrum or intensity [9][10], has been exploited to accurately measure the intracellular pH.…”

Section: Introductionmentioning

confidence: 99%

Targeted nanosensor aided three-dimensional pH mapping in tumor spheroids using two-photon microscopy

et al. 2012

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Tumors are generally characterized by a pH lower than the surrounding tissues. The mapping of tumor pH is of great importance as it plays a critical role in drug delivery and its effectiveness. Here we present a pH mapping technique in tumor spheroids, using targeted, ratiometric, fluorescent, pH nano-sensor that is based on two-photon excitation. Spheroids are micro-tumors that are widely used as an in-vitro three dimensional tumor model to study the different properties of the tumor for the purpose of drug delivery, therapy etc. The nanosensor consists of 8-Hydroxypyrene-1,3,6-trisulfonic acid (HPTS), a pH sensitive dye, encapsulated in polyacrylamide hydrogel nanoparticle matrix and F3 peptide, conjugated to the nanoparticle's surface. The nanosensor has an average size of 68nm and contains approximately 0.5% dye by weight. The fluorescence intensity ratio, at the two-photon excitation wavelengths of 900nm and 750nm, increases linearly in the pH range from 6.0 to 8.0 and is used to determine the pH of the local environment. Our study reveals the pH distribution inside human cervix cancer spheroids (of different sizes) during the various stages of their formation. This information can be used to develop more efficient drug delivery mechanisms. The two-photon excitation used for this purpose is especially useful as it drastically minimizes both photobleaching and autofluorescence, thus leading to an increase in the signal-to-noise ratio. It also enables deep tissue imaging due to higher photon penetration depth.

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Proton imaging of siloxanes to map tissue oxygenation levels (PISTOL): a tool for quantitative tissue oximetry

Cited by 49 publications

References 43 publications

A 1H NMR method for the estimation of hydrogen content for all petroleum products

A 1H NMR method for the estimation of hydrogen content for all petroleum products

A rapid Look-Locker imaging sequence for quantitative tissue oximetry

Targeted nanosensor aided three-dimensional pH mapping in tumor spheroids using two-photon microscopy

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