Proton observed phosphorus editing (POPE) for <i>in vivo</i> detection of phospholipid metabolites

Wijnen, Jannie P.; Klomp, Dennis W. J.; Nabuurs, Christine I. H. C.; Graaf, Robin A. de; Kalleveen, Irene M. L. van; Kemp, Wybe J. M. van der; Luijten, Peter R.; Kruit, Mark C.; Webb, Andrew; Kan, Hermien E.; Boer, Vincent O.

doi:10.1002/nbm.3440

Cited by 12 publications

(11 citation statements)

References 31 publications

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“…The use of a B1‐calibration reference marker (such as in Purvis et al) would also facilitate quantification of metabolite concentration. Further improvements in spectral SNR are possible through implementation of various imaging techniques including AMESING, DIMEPT, and proton observed phosphorus editing . Purvis et al used a 16‐channel phosphorus receive array to acquire 31 P of the liver and Valkovic et al have demonstrated the use of a 31 P birdcage for transmit in combination with a 31 P receive array for cardiac studies .…”

Section: Discussionmentioning

confidence: 99%

“…Further improvements in spectral SNR are possible through implementation of various imaging techniques including AMESING, 22 DIMEPT, 35 and proton observed phosphorus editing. 36 Purvis et al used a 16-channel phosphorus receive array 21 to acquire 31 P of the liver and Valkovic et al have demonstrated the use of a 31 P birdcage for transmit in combination with a 31 P receive array for cardiac studies. 37 In such an approach, both the SNR and the homogeneity of the transmit pulse can be improved.…”

Section: Contributions Strengths and Limitationsmentioning

confidence: 99%

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Inherently decoupled¹H antennas and³¹P loops for metabolic imaging of liver metastasis at 7 T

et al. 2020

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High field 31P spectroscopy has thus far been limited to diffuse liver disease. Unlike lower field‐strength scanners, there is no body coil in the bore of the 7 T and despite inadequate penetration depth (<10 cm), surface coils are the current state‐of‐the‐art for acquiring anatomical images to support multinuclear studies. We present a system of proton antennas and phosphorus loops for 31P spectroscopy and provide the first ultrahigh‐field phosphorus metabolic imaging of a tumor in the abdomen. Herein we characterize the degree to which antennas are isolated from underlying loops. Next, we evaluate the penetration depth of the two antennas available during multinuclear examinations. Finally, we combine phosphorus spectroscopy (two loops) with parallel transmit imaging (eight antennas) in a patient. The loops and antennas are inherently decoupled (no added circuitry, <0.1% power coupling). The penetration depth of two antennas gives twice that of conventional loops. The liver and full axial slice of the abdomen were imaged with eight transmit/receive antennas using parallel transmit B1‐shimming to overcome image voids. Phosphorus spectroscopy from a liver metastasis resolved individual peaks for phosphocholine and phosphoethenalomine. Proton antennas are inherently decoupled from phosphorus loops. By using two proton antennas it is possible to perform region‐of‐interest image‐based shimming in over 80% of the liver volume, thereby enabling phosphorus spectroscopy of localized disease. Shimming of the full extent of the abdominal cross‐section is feasible using a parallel transmit array of eight antennas. A system architecture capable of supporting eight‐channel parallel transmit and multinuclear spectroscopy is optimal for supporting multiparametric body imaging, including metabolic imaging, for monitoring the response of patients with liver metastases to cancer treatments and for patient risk stratification. In the meantime, the existing infrastructure using two antennas is sufficient for preliminary studies in metabolic imaging of tumors in the liver.

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Section: Discussionmentioning

confidence: 99%

Section: Contributions Strengths and Limitationsmentioning

confidence: 99%

Inherently decoupled¹H antennas and³¹P loops for metabolic imaging of liver metastasis at 7 T

et al. 2020

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“…Further improvements in spectral SNR are possible through implementation of various imaging techniques including AMESING, 19 DIMEPT, 27 and proton observed phosphorus editing. 28 Although not widely available, hardware improvements can also be used to boost the 31P SNR. Purvis et al use a 16-channel phosphorus receive array 18 to acquire 31P of the liver and have demonstrated the use of a 31P birdcage for transmit in combination with a 31P receive array for cardiac studies.…”

Section: Discussionmentioning

confidence: 99%

Improved localizers and anatomical images to enable phosphorus magnetic resonance spectroscopy of liver metastasis at 7T

Rivera¹,

Kalleveen²,

Castro³

et al. 2018

Preprint

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Phosphorus spectroscopy (31P) at 7T (300 MHz) enables clinically-relevant spatial resolutions and time scales with high potential for monitoring response to cancer treatment. However, at 7T collecting a radiological-grade anatomical image of the liver—which is required for performing localized 31P spectroscopy—presents a challenge. Unlike lower field-strength scanners, there is no body coil in the bore of the 7T and despite inadequate penetration depth (<10 cm), surface coils are the current state-of-the-art for acquiring anatomical (1H) images. Therefore, thus far, high field 31P spectroscopy has been limited to diffuse liver disease. However, the use of antennas enable improved penetration depths at 300 MHz, and when combined with parallel transmit, can enable body imaging at 7T. We have developed a protocol for imaging liver metastases of patients using parallel transmit and 31P spectroscopy at 7T. We used a custom-made liver coil consisting of eight 30-cm dipole antennas tuned to the proton (300 MHz) frequency, and two partially overlapping 20-cm-diameter loops tuned for 31P (120 MHz). The field of view afforded by the two antennas underneath the 31P loops is not sufficient to image the complete boundaries of the liver for chemical shift imaging (CSI) planning and region-of-interest-based B0 shimming. The liver and full axial slice of the abdomen was imaged with eight transmit/receive antennas using parallel transmit B1-shimming to overcome image voids. Through the use of antennas we overcome the challenges for multi-parametric body imaging, and can begin to explore the possibility of monitoring the response of patients with liver metastasis to cancer treatments.ABBREVIATIONS(PDE)Phosphodiester(GPE)Glycerophosphoethanolamine(GPC)Glycerophosphocholine(PME)Phosphomonoesther(PC)Phosphocholine(PE)Phosphoethanalomine(PI)Inorganic Phosphate(PCR)Phosphocreatine(PTC)Phophotidylcholine(CSI)Chemical Shift Imaging(GE)Gradient Echo(L)Left(R)Right(H)Head(F)Foot(A)Anterior(P)Posterior(TR)Repetition Time(TE)Echo Time

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“…With the availability of higher‐field‐strength magnets for MRI in clinics and the use of efficient dedicated quadrature RF coils for the breast along with editing RF sequences, improved sensitivity of 31 P signals was seen. It is now possible to resolve individual phosphate metabolites such as the combined peak for PME and PDE and other phosphorus resonances . Moreover, the use of multi‐voxel MRS at 7 T in breast cancer patients showed detection of various phospholipid metabolites such as PCho, GPC, phosphoethanolamine, glycerophosphoethanolamine and nucleotide triphosphates, and their absolute concentrations could be determined .…”

Section: In Vivo Mrs Methods In the Study Of Breast Cancer Metabolismmentioning

confidence: 99%

Application of in vivo MR methods in the study of breast cancer metabolism

Jagannathan

2018

NMR in Biomedicine

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In the last two decades, various in vivo MR methodologies have been evaluated for their potential in the study of cancer metabolism. During malignant transformation, metabolic alterations occur, leading to morphological and functional changes. Among various MR methods, in vivo MRS has been extensively used in breast cancer to study the metabolism of cells, tissues or whole organs. It provides biochemical information at the metabolite level. Altered choline, phospholipid and energy metabolism has been documented using proton ( 1 H), phosphorus ( 31 P) and carbon ( 13 C) isotopes. Increased levels of choline-containing compounds, phosphomonoesters and phosphodiesters in breast cancer, which are indicative of altered choline and phospholipid metabolism, have been reported using in vivo, in vitro and ex vivo NMR studies. These changes are reversed on successful therapy, which depends on the treatment regimen given.Monitoring the various tumor intermediary metabolic pathways using nuclear spin hyperpolarization of 13 C-labeled substrates by dynamic nuclear polarization has also been recently reported. Furthermore, the utility of various methods such as diffusion, dynamic contrast and perfusion MRI have also been evaluated to study breast tumor metabolism. Parameters such as tumor volume, apparent diffusion coefficient, volume transfer coefficient and extracellular volume ratio are estimated. These parameters provide information on the changes in tumor microstructure, microenvironment, abnormal vasculature, permeability and grade of the tumor. Such changes seen during cancer progression are due to alterations in the tumor metabolism, leading to changes in cell architecture. Due to architectural changes, the tissue mechanical properties are altered; this can be studied using magnetic resonance elastography, which measures the elastic properties of tissues. Moreover, these structural MRI methods can be used to investigate the effect of therapy-induced changes in tumor characteristics. This review discusses the potential of various in vivo MR methodologies in the study of breast cancer metabolism.

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Proton observed phosphorus editing (POPE) for in vivo detection of phospholipid metabolites

Cited by 12 publications

References 31 publications

Inherently decoupled¹H antennas and³¹P loops for metabolic imaging of liver metastasis at 7 T

Inherently decoupled¹H antennas and³¹P loops for metabolic imaging of liver metastasis at 7 T

Improved localizers and anatomical images to enable phosphorus magnetic resonance spectroscopy of liver metastasis at 7T

Application of in vivo MR methods in the study of breast cancer metabolism

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Proton observed phosphorus editing (POPE) for in vivo detection of phospholipid metabolites

Cited by 12 publications

References 31 publications

Inherently decoupled1H antennas and31P loops for metabolic imaging of liver metastasis at 7 T

Inherently decoupled1H antennas and31P loops for metabolic imaging of liver metastasis at 7 T

Improved localizers and anatomical images to enable phosphorus magnetic resonance spectroscopy of liver metastasis at 7T

Application of in vivo MR methods in the study of breast cancer metabolism

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Inherently decoupled¹H antennas and³¹P loops for metabolic imaging of liver metastasis at 7 T

Inherently decoupled¹H antennas and³¹P loops for metabolic imaging of liver metastasis at 7 T