From the Departments of Radiology (L.Z., X. Long, L.C., X.H., Z.L., B.L., X. Liu, H.S.) and Pathology (J.F.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Ave, Wuhan 430022, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China (L.Z., X. Long, L.C., X.H., Z.L., B.L., X. Liu, H.S.); Department of Clinical & Technical Solutions, Philips Healthcare, Beijing, China (X.Z., P.S., J.W.); Department of Pathology, Wuhan Hospital of Traditional Chinese and Western Medicine, Wuhan, China (Y.Y.); and National Engineering Research Center for Nanomedicine, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China (X. Liu).
Radiology. 2024 Oct;313(1):e240343. doi: 10.1148/radiol.240343.
Background The potential of time-dependent diffusion MRI in imaging the progression from liver fibrosis to cirrhosis has not been established. Purpose To assess the effectiveness of time-dependent diffusion MRI in mapping the microstructure and characterizing cellular attributes during the progression of liver fibrosis to cirrhosis and to investigate its potential in grading liver fibrosis. Materials and Methods This prospective study, performed between December 2022 and October 2023, used 60 rats to establish a liver fibrosis model by means of diethylnitrosamine administration, with five additional rats serving as control animals. Time-dependent diffusion MRI was performed with equivalent diffusion time of 5.4, 10.7, and 69.3 msec on a 3.0-T scanner. Time-dependent diffusion MRI-based microstructural parameters, including cell diameter, intracellular volume fraction (ICVF), cellularity, and extracellular diffusivity, were estimated with use of the imaging microstructural parameters using limited spectrally edited diffusion, or IMPULSED, model. The fitted microstructural parameters were validated with histopathologic measurements. Results All 60 rats developed liver fibrosis, with a noticeable decrease in cell diameter and an increase in ICVF and cellularity observed as liver fibrosis progressed. The diameter measured at pathologic examination ranged from 11.4 μm to 35.4 μm, aligning with the range of 12.4-33.4 μm observed in time-dependent diffusion MRI, which indicated a strong correlation ( = 0.84; < .001). The quantified ICVF at pathologic examination ranged from 0.28 to 0.89 and varied from 0.23 to 0.85 at time-dependent diffusion MRI, showing a high correlation ( = 0.62; < .001). The cellularity observed at pathologic examination increased from 0.74 to 5.85, while the cellularity measured at time-dependent diffusion MRI ranged from 0.77 to 3.70, showing a correlation ( = 0.44; < .001). Conclusion This study revealed the changes in quantitative microstructural mapping across the spectrum from liver fibrosis to cirrhosis. Cell diameter, ICVF, and cellularity are reliable markers for liver fibrosis, with diameter and ICVF presenting good discrimination ability. © RSNA, 2024 See also the editorial by Matos and Metens in this issue.
时变扩散 MRI 在成像肝纤维化向肝硬化进展方面的潜力尚未得到证实。目的：评估时变扩散 MRI 对肝纤维化向肝硬化进展过程中微观结构进行成像和对细胞属性进行特征描述的有效性，并研究其在肝纤维化分级中的潜在价值。材料与方法：本前瞻性研究于 2022 年 12 月至 2023 年 10 月期间进行，使用 60 只大鼠通过二乙基亚硝胺给药建立肝纤维化模型，另有 5 只大鼠作为对照动物。在 3.0-T 扫描仪上进行时变扩散 MRI，扩散时间相等，分别为 5.4、10.7 和 69.3 毫秒。使用基于成像微观结构参数的有限光谱编辑扩散或 IMPULSED 模型，估计时变扩散 MRI 相关的微观结构参数，包括细胞直径、细胞内体积分数（ICVF）、细胞密度和细胞外扩散率。拟合的微观结构参数通过组织病理学测量进行验证。结果：所有 60 只大鼠均发生肝纤维化，随着肝纤维化的进展，细胞直径明显减小，ICVF 和细胞密度增加。病理检查测量的直径范围为 11.4 μm 至 35.4 μm，与时变扩散 MRI 观察到的 12.4-33.4 μm 范围一致，表明两者之间存在很强的相关性（ = 0.84； <.001）。病理检查量化的 ICVF 范围为 0.28 至 0.89，时变扩散 MRI 范围为 0.23 至 0.85，相关性很高（ = 0.62； <.001）。病理检查观察到的细胞密度从 0.74 增加到 5.85，而时变扩散 MRI 测量的细胞密度范围从 0.77 增加到 3.70，相关性为 0.44； <.001）。结论：本研究揭示了从肝纤维化到肝硬化的定量微观结构图谱的变化。细胞直径、ICVF 和细胞密度是肝纤维化的可靠标志物，其中直径和 ICVF 具有良好的鉴别能力。© RSNA，2024 参见本期 Matos 和 Metens 的社论。
