High spatiotemporal resolution bSSFP imaging of hyperpolarized [1‐<sup>13</sup>C]pyruvate and [1‐<sup>13</sup>C]lactate with spectral suppression of alanine and pyruvate‐hydrate

Milshteyn, Eugene; Morze, Cornelius von; Gordon, Jeremy W.; Zhu, Zihan; Larson, Peder E. Z.; Vigneron, Daniel B.

doi:10.1002/mrm.27104

Cited by 20 publications

(40 citation statements)

References 45 publications

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“…At this stage, it appears that existing kinetic models do not adequately account for T 2 or T 2 * weightings. One option is to estimate relaxation times using the HP‐ 13 C T 1 and T 2 mapping methods based on bSSFP …”

Section: Discussionmentioning

confidence: 99%

“…One solution is to delay the start of acquisition until bolus clearance from arteries. Appealing alternatives to DSE are balanced steady‐state free precession (bSSFP) sequences, which can also exploit long T 1 and T 2 to improve lactate SNR.…”

Section: Discussionmentioning

confidence: 99%

“…One option is to estimate relaxation times using the HP-13 C T 1 and T 2 mapping methods based on bSSFP. 47,52 Generally speaking, the amount of a priori knowledge about the tissue properties and pharmacokinetic behaviors still imposes a limit on model performance. Akaike's information criterion serves as a good benchmark to determine if additional factors will benefit the model/fit based on in vivo data.…”

Section: Potential Strategies For Robust Quantificationmentioning

confidence: 99%

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Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion k_PL in hyperpolarized ¹³C imaging

et al. 2019

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Hyperpolarized 13C MRI takes advantage of the unprecedented 50 000‐fold signal‐to‐noise ratio enhancement to interrogate cancer metabolism in patients and animals. It can measure the pyruvate‐to‐lactate conversion rate, kPL, a metabolic biomarker of cancer aggressiveness and progression. Therefore, it is crucial to evaluate kPL reliably. In this study, three sequence components and parameters that modulate kPL estimation were identified and investigated in model simulations and through in vivo animal studies using several specifically designed pulse sequences. These factors included a magnetization spoiling effect due to RF pulses, a crusher gradient‐induced flow suppression, and intrinsic image weightings due to relaxation. Simulation showed that the RF‐induced magnetization spoiling can be substantially improved using an inputless kPL fitting. In vivo studies found a significantly higher apparent kPL with an additional gradient that leads to flow suppression (kPL,FID‐Delay,Crush/kPL,FID‐Delay = 1.37 ± 0.33, P < 0.01, N = 6), which agrees with simulation outcomes (12.5% kPL error with Δv = 40 cm/s), indicating that the gradients predominantly suppressed flowing pyruvate spins. Significantly lower kPL was found using a delayed free induction decay (FID) acquisition versus a minimum‐TE version (kPL,FID‐Delay/kPL,FID = 0.67 ± 0.09, P < 0.01, N = 5), and the lactate peak had broader linewidth than pyruvate (Δωlactate/Δωpyruvate = 1.32 ± 0.07, P < 0.000 01, N = 13). This illustrated that lactate's T2*, shorter than that of pyruvate, can affect calculated kPL values. We also found that an FID sequence yielded significantly lower kPL versus a double spin‐echo sequence that includes spin‐echo spoiling, flow suppression from crusher gradients, and more T2 weighting (kPL,DSE/kPL,FID = 2.40 ± 0.98, P < 0.0001, N = 7). In summary, the pulse sequence, as well as its interaction with pharmacokinetics and the tissue microenvironment, can impact and be optimized for the measurement of kPL. The data acquisition and analysis pipelines can work synergistically to provide more robust and reproducible kPL measures for future preclinical and clinical studies.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Potential Strategies For Robust Quantificationmentioning

confidence: 99%

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Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion k_PL in hyperpolarized ¹³C imaging

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“…[9][10][11][12] The MR signals of the hyperpolarized [1-13 C]pyruvate (173 ppm) and its downstream metabolites-[1-13 C] lactate (185 ppm), [1-13 C]pyruvate hydrate (181 ppm), [1-13 C] bicarbonate (163 ppm) and [1-13 C]alanine (178 ppm)-are typically acquired using gradient echo ("GRE") sequences (CSI, 2,13 multi-echo IDEAL, 14,15 metabolite-specific EPI 16,17 or spiral 18 acquisition), where the transverse magnetization is spoiled at the end of each repetition time. Compared to GRE acquisitions, the balanced steady-state free precession ("bSSFP") [19][20][21][22][23][24][25] sequence can acquire the nonrenewable hyperpolarized magnetization more efficiently by repetitively refocusing transverse spins, which is especially valuable for imaging metabolites with long T 2 s 23,26 such as [1-13 C]pyruvate or [1-13 C] lactate.…”

Section: Introductionmentioning

confidence: 99%

“…The second strategy 24 reduced the number of excited compounds-only excited lactate, pyruvate hydrate, and alanine-and applied a saturation pulse to suppress undesired signals from alanine and pyruvate hydrate at the beginning of each bSSFP acquisition. There are three main drawbacks in this strategy.…”

Section: Introductionmentioning

confidence: 99%

A metabolite‐specific 3D stack‐of‐spiral bSSFP sequence for improved lactate imaging in hyperpolarized [1‐¹³C]pyruvate studies on a 3T clinical scanner

Tang

Bok

Qin

et al. 2020

Magnetic Resonance in Med

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Purpose:The balanced steady-state free precession sequence has been previously explored to improve the efficient use of nonrecoverable hyperpolarized 13 C magnetization, but suffers from poor spectral selectivity and long acquisition time.The purpose of this study was to develop a novel metabolite-specific 3D bSSFP ("MS-3DSSFP") sequence with stack-of-spiral readouts for improved lactate imaging in hyperpolarized [1-13 C]pyruvate studies on a clinical 3T scanner. Methods: Simulations were performed to evaluate the spectral response of the MS-3DSSFP sequence. Thermal 13 C phantom experiments were performed to validate the MS-3DSSFP sequence. In vivo hyperpolarized [1-13 C], pyruvate studies were performed to compare the MS-3DSSFP sequence with metabolite-specific gradient echo ("MS-GRE") sequences for lactate imaging. Results: Simulations, phantom, and in vivo studies demonstrate that the MS-3DSSFP sequence achieved spectrally selective excitation on lactate while minimally perturbing other metabolites. Compared with MS-GRE sequences, the MS-3DSSFP sequence showed approximately a 2.5-fold SNR improvement for lactate imaging in rat kidneys, prostate tumors in a mouse model, and human kidneys. Conclusions: Improved lactate imaging using the MS-3DSSFP sequence in hyperpolarized [1-13 C]pyruvate studies was demonstrated in animals and humans. The MS-3DSSFP sequence could be applied for other clinical applications such as in the brain or adapted for imaging other metabolites such as pyruvate and bicarbonate. K E Y W O R D S13 C, bSSFP, hyperpolarized, lactate, metabolic imaging, MRI, pyruvate 1114 | TANG eT Al.

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Fast Imaging for Hyperpolarized MR Metabolic Imaging

Gordon

Chen

Dwork

et al. 2020

Magnetic Resonance Imaging

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MRI with hyperpolarized carbon‐13 agents has created a new type of noninvasive, in vivo metabolic imaging that can be applied in cell, animal, and human studies. The use of 13C‐labeled agents, primarily [1‐13C]pyruvate, enables monitoring of key metabolic pathways with the ability to image substrate and products based on their chemical shift. Over 10 sites worldwide are now performing human studies with this new approach for studies of cancer, heart disease, liver disease, and kidney disease. Hyperpolarized metabolic imaging studies must be performed within several minutes following creation of the hyperpolarized agent due to irreversible decay of the net magnetization back to equilibrium, so fast imaging methods are critical. The imaging methods must include multiple metabolites, separated based on their chemical shift, which are also undergoing rapid metabolic conversion (via label exchange), further exacerbating the challenges of fast imaging. This review describes the state‐of‐the‐art in fast imaging methods for hyperpolarized metabolic imaging. This includes the approach and tradeoffs between three major categories of fast imaging methods—fast spectroscopic imaging, model‐based strategies, and metabolite specific imaging—as well additional options of parallel imaging, compressed sensing, tailored RF flip angles, refocused imaging methods, and calibration methods that can improve the scan coverage, speed, signal‐to‐noise ratio (SNR), resolution, and/or robustness of these studies. To date, these approaches have produced extremely promising initial human imaging results. Improvements to fast hyperpolarized metabolic imaging methods will provide better coverage, SNR, resolution, and reproducibility for future human imaging studies. Level of Evidence 5 Technical Efficacy Stage 1

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High spatiotemporal resolution bSSFP imaging of hyperpolarized [1‐¹³C]pyruvate and [1‐¹³C]lactate with spectral suppression of alanine and pyruvate‐hydrate

Abstract: The developed framework presented here shows the capability for dynamic high resolution volumetric hyperpolarized bSSFP imaging of pyruvate-to-lactate conversion on a clinical 3T MR scanner.

Cited by 20 publications

References 45 publications

Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion k_PL in hyperpolarized ¹³C imaging

Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion k_PL in hyperpolarized ¹³C imaging

A metabolite‐specific 3D stack‐of‐spiral bSSFP sequence for improved lactate imaging in hyperpolarized [1‐¹³C]pyruvate studies on a 3T clinical scanner

Fast Imaging for Hyperpolarized MR Metabolic Imaging

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High spatiotemporal resolution bSSFP imaging of hyperpolarized [1‐13C]pyruvate and [1‐13C]lactate with spectral suppression of alanine and pyruvate‐hydrate

Abstract: The developed framework presented here shows the capability for dynamic high resolution volumetric hyperpolarized bSSFP imaging of pyruvate-to-lactate conversion on a clinical 3T MR scanner.

Cited by 20 publications

References 45 publications

Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion kPL in hyperpolarized 13C imaging

Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion kPL in hyperpolarized 13C imaging

A metabolite‐specific 3D stack‐of‐spiral bSSFP sequence for improved lactate imaging in hyperpolarized [1‐13C]pyruvate studies on a 3T clinical scanner

Fast Imaging for Hyperpolarized MR Metabolic Imaging

Contact Info

Product

Resources

About

High spatiotemporal resolution bSSFP imaging of hyperpolarized [1‐¹³C]pyruvate and [1‐¹³C]lactate with spectral suppression of alanine and pyruvate‐hydrate

Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion k_PL in hyperpolarized ¹³C imaging

Pulse sequence considerations for quantification of pyruvate‐to‐lactate conversion k_PL in hyperpolarized ¹³C imaging

A metabolite‐specific 3D stack‐of‐spiral bSSFP sequence for improved lactate imaging in hyperpolarized [1‐¹³C]pyruvate studies on a 3T clinical scanner