Dataset Information

Simultaneous T₁ and T₂ mapping of hyperpolarized ¹³C compounds using the bSSFP sequence.

ABSTRACT: As in conventional ¹H MRI, T₁ and T₂ relaxation times of hyperpolarized (HP) ¹³C nuclei can provide important biomedical information. Two new approaches were developed for simultaneous T₁ and T₂ mapping of HP ¹³C probes based on balanced steady state free precession (bSSFP) acquisitions: a method based on sequential T₁ and T₂ mapping modules, and a model-based joint T₁/T₂ approach analogous to MR fingerprinting. These new methods were tested in simulations, HP ¹³C phantoms, and in vivo in normal Sprague-Dawley rats. Non-localized T₁ values, low flip angle EPI T₁ maps, bSSFP T₂ maps, and Bloch-Siegert B₁ maps were also acquired for comparison. T₁ and T₂ maps acquired using both approaches were in good agreement with both literature values and data from comparative acquisitions. Multiple HP ¹³C compounds were successfully mapped, with their relaxation time parameters measured within heart, liver, kidneys, and vasculature in one acquisition for the first time.

SUBMITTER: Milshteyn E

PROVIDER: S-EPMC7227792 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Publications

Simultaneous T1 and T2 mapping of hyperpolarized 13C compounds using the bSSFP sequence.

Milshteyn Eugene E Reed Galen D GD Gordon Jeremy W JW von Morze Cornelius C Cao Peng P Tang Shuyu S Leynes Andrew P AP Larson Peder E Z PEZ Vigneron Daniel B DB

Journal of magnetic resonance (San Diego, Calif. : 1997) 20200201

As in conventional 1H MRI, T1 and T2 relaxation times of hyperpolarized (HP) 13C nuclei can provide important biomedical information. Two new approaches were developed for simultaneous T1 and T2 mapping of HP 13C probes based on balanced steady state free precession (bSSFP) acquisitions: a method based on sequential T1 and T2 mapping modules, and a model-based joint T1/T2 appr ...[more]

PMID: 32058912

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Project description:BackgroundThree-dimensional (3D) multiecho balanced steady-state free precession (ME-bSSFP) has previously been demonstrated in preclinical hyperpolarized (HP) 13 C-MRI in vivo experiments, and it may be suitable for clinical metabolic imaging of prostate cancer (PCa).PurposeTo validate a signal simulation framework for the use of sequence parameter optimization. To demonstrate the feasibility of ME-bSSFP for HP 13 C-MRI in patients. To evaluate the metabolism in PCa measured by ME-bSSFP.Study typeRetrospective single-center cohort study.Phantoms/populationPhantoms containing aqueous solutions of [1-13 C] lactate (2.3 M) and [13 C] urea (8 M). Eight patients (mean age 67 ± 6 years) with biopsy-confirmed Gleason 3 + 4 (n = 7) and 4 + 3 (n = 1) PCa. FIELD STRENGTH/SEQUENCES: 1 H MRI at 3 T with T2 -weighted turbo spin-echo sequence used for spatial localization and spoiled dual gradient-echo sequence used for B0 -field measurement. ME-bSSFP sequence for 13 C MR spectroscopic imaging with retrospective multipoint IDEAL metabolite separation.AssessmentThe primary endpoint was the analysis of pyruvate-to-lactate conversion in PCa and healthy prostate regions of interest (ROIs) using model-free area under the curve (AUC) ratios and a one-directional kinetic model (kP ). The secondary objectives were to investigate the correlation between simulated and experimental ME-bSSFP metabolite signals for HP 13 C-MRI parameter optimization.Statistical testsPearson correlation coefficients with 95% confidence intervals and paired t-tests. The level of statistical significance was set at P < 0.05.ResultsStrong correlations between simulated and empirical ME-bSSFP signals were found (r > 0.96). Therefore, the simulation framework was used for sequence optimization. Whole prostate metabolic HP 13 C-MRI, observing the conversion of pyruvate into lactate, with a temporal resolution of 6 seconds was demonstrated using ME-bSSFP. Both assessed metrics resulted in significant differences between PCa (mean ± SD) (AUC = 0.33 ± 012, kP = 0.038 ± 0.014) and healthy (AUC = 0.15 ± 0.10, kP = 0.011 ± 0.007) ROIs.Data conclusionMetabolic HP 13 C-MRI in the prostate using ME-bSSFP allows for differentiation between aggressive PCa and healthy tissue.Evidence level2 TECHNICAL EFFICACY: Stage 1.

Dataset Information

Simultaneous T₁ and T₂ mapping of hyperpolarized ¹³C compounds using the bSSFP sequence.

Publications

Simultaneous T<sub>1</sub> and T<sub>2</sub> mapping of hyperpolarized <sup>13</sup>C compounds using the bSSFP sequence.

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