Improved tolerance to off‐resonance in spectral‐spatial EPI of hyperpolarized [1‐<sup>13</sup>C]pyruvate and metabolites

Lau, Justin Y. C.; Geraghty, Benjamin; Chen, Albert P.; Cunningham, Charles H.

doi:10.1002/mrm.27086

Cited by 10 publications

(10 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this will place more of a burden on shimming and frequency calibration, as a further increase in echo‐spacing would make the acquisition more susceptible to geometric distortion and bulk shifts in the blip dimension. In this case, alternating the blip polarity each time frame or using a dual‐echo EPI acquisition could potentially be used to correct for distortion and signal loss arising from B 0 inhomogeneity.…”

Section: Discussionmentioning

confidence: 99%

Translation of Carbon‐13 EPI for hyperpolarized MR molecular imaging of prostate and brain cancer patients

Gordon

Chen

Autry

et al. 2018

Magnetic Resonance in Med

View full text Add to dashboard Cite

Purpose To develop and translate a metabolite‐specific imaging sequence using a symmetric echo planar readout for clinical hyperpolarized (HP) Carbon‐13 (13C) applications. Methods Initial data were acquired from patients with prostate cancer (N = 3) and high‐grade brain tumors (N = 3) on a 3T scanner. Samples of [1‐13C]pyruvate were polarized for at least 2 h using a 5T SPINlab system operating at 0.8 K. Following injection of the HP substrate, pyruvate, lactate, and bicarbonate (for brain studies) were sequentially excited with a singleband spectral‐spatial RF pulse and signal was rapidly encoded with a single‐shot echo planar readout on a slice‐by‐slice basis. Data were acquired dynamically with a temporal resolution of 2 s for prostate studies and 3 s for brain studies. Results High pyruvate signal was seen throughout the prostate and brain, with conversion to lactate being shown across studies, whereas bicarbonate production was also detected in the brain. No Nyquist ghost artifacts or obvious geometric distortion from the echo planar readout were observed. The average error in center frequency was 1.2 ± 17.0 and 4.5 ± 1.4 Hz for prostate and brain studies, respectively, below the threshold for spatial shift because of bulk off‐resonance. Conclusion This study demonstrated the feasibility of symmetric EPI to acquire HP 13C metabolite maps in a clinical setting. As an advance over prior single‐slice dynamic or single time point volumetric spectroscopic imaging approaches, this metabolite‐specific EPI acquisition provided robust whole‐organ coverage for brain and prostate studies while retaining high SNR, spatial resolution, and dynamic temporal resolution.

show abstract

Section: Discussionmentioning

confidence: 99%

Translation of Carbon‐13 EPI for hyperpolarized MR molecular imaging of prostate and brain cancer patients

Gordon

Chen

Autry

et al. 2018

Magnetic Resonance in Med

View full text Add to dashboard Cite

show abstract

“…Another weakness results from the use of SPSP excitation: when acquiring data over large volumes, shimming becomes more challenging and so does off‐resonance excitation artifacts. In a recent study by Lau et al, such artifacts were mitigated by increasing the spectral passband of the SPSP pulse and acquiring multiple echoes to resolve signal contamination in the reconstruction, similar to IDEAL . Besides being sensitive to off‐resonance, the used SPSP pulse was also rather long.…”

Section: Discussionmentioning

confidence: 99%

Coil profile estimation strategies for parallel imaging with hyperpolarized ¹³C MRI

Hansen

Sánchez‐Heredia

Bøgh

et al. 2019

Magnetic Resonance in Med

View full text Add to dashboard Cite

Purpose To investigate auto‐ and pre‐calibration coil profile estimation for parallel imaging reconstruction of hyperpolarized 13C MRI volumetric data. Methods Parallel imaging reconstruction was studied with 3 different approaches for coil profile estimation: auto‐calibration, phantom calibration, and theoretic calibration. Acquisition was performed with a 3D stack‐of‐spirals sequence with spectral–spatial excitation and Cartesian undersampling. Parallel imaging reconstructions were done with conjugate gradient SENSE and 3D gridding with inhomogeneity correction. The approaches were compared in simulations with different SNR, through phantom experiments, and in an in vivo pig study focused on the kidneys. All imaging was done with a rigid home‐built 12‐channel 13C receive coil at 3T. Results The phantom calibrated and theoretic approaches resulted in the best structural similarities in simulations and demonstrated higher image quality in the phantom experiments compared to the auto‐calibrated approach. In vivo mapping of pyruvate uptake and lactate conversion improved for accelerated acquisitions because of a better temporal resolution. From a practical and image quality point of view, use of theoretic coil profiles led to improved results compared to the other approaches. Conclusion The success of the theoretic coil profile estimation demonstrates a negligible effect of load on sensitivity profiles at the carbon frequency at 3T. Through theoretic or phantom calibrated parallel imaging, accelerated 3D volumes could be reconstructed with sufficient sensitivity, temporal, and spatial resolution to map the metabolism of kidneys exemplifying abdominal organs. This approach overcomes a critical step in the clinical translation of parallel imaging in hyperpolarized 13C MR.

show abstract

“…Therefore, we suggest that the sensitivity toward changes in oxygen supply defines an alternative diabetic phenotype, indicating reduction in active cellular uptake of pyruvate. A potential limitation in the study design is the use of CSI for spatial localization of the metabolites, limiting the spatial resolution and especially the temporal resolution compared with faster or higher resolution imaging methods (26, 36–39). Another limitation is the need for anesthetics, which have been shown to impact the renal metabolism (40), although the used regime has only mild renal effects compared with other anesthetic regimes.…”

Section: Discussionmentioning

confidence: 99%

High Intrarenal Lactate Production Inhibits the Renal Pseudohypoxic Response to Acutely Induced Hypoxia in Diabetes

et al. 2019

View full text Add to dashboard Cite

Intrarenal hypoxia develops within a few days after the onset of insulinopenic diabetes in an experimental animal model (ie, a model of type-1 diabetes). Although diabetes-induced hypoxia results in increased renal lactate formation, mitochondrial function is well maintained, a condition commonly referred to as pseudohypoxia. However, the metabolic effects of significantly elevated lactate levels remain unclear. We therefore investigated in diabetic animals the response to acute intrarenal hypoxia in the presence of high renal lactate formation to delineate mechanistic pathways and compare these findings to healthy control animals. Hyperpolarized 13 C-MRI and blood oxygenation level–dependent 1 H-MRI was used to investigate the renal metabolism of [1- 13 C]pyruvate and oxygenation following acutely altered oxygen content in the breathing gas in a streptozotocin rat model of type-1 diabetes with and without insulin treatment and compared with healthy control rats. The lactate signal in the diabetic kidney was reduced by 12%–16% during hypoxia in diabetic rats irrespective of insulin supplementation. In contrast, healthy controls displayed the well-known Pasteur effect manifested as a 10% increased lactate signal following reduction of oxygen in the inspired air. Reduced expression of the monocarboxyl transporter-4 may account for altered response to hypoxia in diabetes with a high intrarenal pyruvate-to-lactate conversion. Reduced intrarenal lactate formation in response to hypoxia in diabetes shows the existence of a different metabolic phenotype, which is independent of insulin, as insulin supplementation was unable to affect the pyruvate-to-lactate conversion in the diabetic kidney.

show abstract

Improved tolerance to off‐resonance in spectral‐spatial EPI of hyperpolarized [1‐¹³C]pyruvate and metabolites

Abstract: Improved tolerance to off-resonance in the new C data acquisition pipeline was demonstrated in vitro and in vivo. Magn Reson Med 80:925-934, 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Cited by 10 publications

References 32 publications

Translation of Carbon‐13 EPI for hyperpolarized MR molecular imaging of prostate and brain cancer patients

Translation of Carbon‐13 EPI for hyperpolarized MR molecular imaging of prostate and brain cancer patients

Coil profile estimation strategies for parallel imaging with hyperpolarized ¹³C MRI

High Intrarenal Lactate Production Inhibits the Renal Pseudohypoxic Response to Acutely Induced Hypoxia in Diabetes

Contact Info

Product

Resources

About

Improved tolerance to off‐resonance in spectral‐spatial EPI of hyperpolarized [1‐13C]pyruvate and metabolites

Abstract: Improved tolerance to off-resonance in the new C data acquisition pipeline was demonstrated in vitro and in vivo. Magn Reson Med 80:925-934, 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Cited by 10 publications

References 32 publications

Translation of Carbon‐13 EPI for hyperpolarized MR molecular imaging of prostate and brain cancer patients

Translation of Carbon‐13 EPI for hyperpolarized MR molecular imaging of prostate and brain cancer patients

Coil profile estimation strategies for parallel imaging with hyperpolarized 13C MRI

High Intrarenal Lactate Production Inhibits the Renal Pseudohypoxic Response to Acutely Induced Hypoxia in Diabetes

Contact Info

Product

Resources

About

Improved tolerance to off‐resonance in spectral‐spatial EPI of hyperpolarized [1‐¹³C]pyruvate and metabolites

Coil profile estimation strategies for parallel imaging with hyperpolarized ¹³C MRI