Finding an effective MRI sequence to visualise the electroporated area in plant-based models by quantitative mapping

Abstract

Plant-based models can reduce the number of animal studies for electroporation research in medical cancer treatment modalities like irreversible electroporation. Magnetic resonance imaging (MRI) provides volumetric visualisation of electroporated animal or plant tissues; however, contrast behaviour is complex, depending on tissue and sequence parameters. This study numerically analysed contrast between electroporated and non-electroporated tissue at 1.5 T in various MRI sequences (DWI, T1W, T2W, T2*W, PDW, FLAIR) performed 4 h after electroporation in apples (N = 4) and potatoes (N = 8). Sequence parameters (inversion time [TI], echo time [TE], b-value) for optimal contrast and electroporation-mediated changes in T1 and T2 relaxation times and apparent diffusion coefficient (ADC) were determined for potato (N = 4) using quantitative parameter mapping. FLAIR showed the electroporated zone in potatoes with best contrast, whereas no sequence yielded clear visibility in apples. After electroporation, T1 and T2 in potato decreased by 29% ([1245 ± 54 to 886 ± 119] ms) and 12% ([249 ± 17 to 217 ± 12] ms), respectively. ADC increased by 11% ([1303 ± 25 to 1449 ± 28] × 10-6 mm²/s). Optimal contrast was found for TI = 1000 ms, low TE and high b-value. T1 was most sensitive to EP-mediated tissue changes. Future research could use this methodology and findings to obtain high-contrast MR images of electroporated and non-electroporated biological tissues.

Keywords: Image contrast; Irreversible electroporation; Magnetic resonance imaging; Quantitative mapping; Sequence optimization.