Quantification of Prostate Cancer Metabolism Using 3D Multiecho bSSFP and Hyperpolarized [1‐¹³C] Pyruvate: Metabolism Differs Between Tumors of the Same Gleason Grade.

Chowdhury, Rafat; Mueller, Christoph A.; Smith, Lorna; Gong, Fiona; Papoutsaki, Marianthi‐Vasiliki; Rogers, Harriet; Syer, Tom; Singh, Saurabh; Brembilla, Giorgio; Retter, Adam; Bullock, Max; Caselton, Lucy; Mathew, Manju; Dineen, Eoin; Parry, Thomas; Hennig, Jürgen; von Elverfeldt, Dominik; Schmidt, Andreas B.; Hövener, Jan‐Bernd; Emberton, Mark

Background: Three‐dimensional (3D) multiecho balanced steady‐state free precession (ME‐bSSFP) has previously been demonstrated in preclinical hyperpolarized (HP) 13C‐MRI in vivo experiments, and it may be suitable for clinical metabolic imaging of prostate cancer (PCa). Purpose: To validate a signal simulation framework for the use of sequence parameter optimization. To demonstrate the feasibility of ME‐bSSFP for HP 13C‐MRI in patients. To evaluate the metabolism in PCa measured by ME‐bSSFP. Study Type: Retrospective single‐center cohort study. Phantoms/Population: Phantoms containing aqueous solutions of [1‐13C] lactate (2.3 M) and [13C] 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: 1H 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 13C MR spectroscopic imaging with retrospective multipoint IDEAL metabolite separation. Assessment: The 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 13C‐MRI parameter optimization. Statistical Tests: Pearson correlation coefficients with 95% confidence intervals and paired t‐tests. The level of statistical significance was set at P < 0.05. Results: Strong 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 13C‐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 Conclusion: Metabolic HP 13C‐MRI in the prostate using ME‐bSSFP allows for differentiation between aggressive PCa and healthy tissue. Evidence Level: 2 Technical Efficacy: Stage 1

PROSTATE cancer; PYRUVATES; METABOLISM; PEARSON correlation (Statistics); SPECTROSCOPIC imaging; MAGNETIC resonance imaging

Journal of Magnetic Resonance Imaging, 2023, Vol 57, Issue 6, p1865

1053-1807

Academic Journal

10.1002/jmri.28467