Yang Fan, Wei Haoran, Li Xiaolu, Yu Xiaoduo, Li Lin, Zhao Yanfeng, Xie Lizhi, Jiang Yueluan, Lin Meng, Zhang Hongmei
Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Department of Radiology, Division of Neuroimaging and Neurointervention, Stanford University, Stanford University Medical Center, Stanford, California, USA.
J Magn Reson Imaging. 2025 Jul;62(1):73-86. doi: 10.1002/jmri.29725. Epub 2025 Mar 10.
IVIM is a useful quantitative tool for predicting prognosis, but it is labor-intensive. Simplified b-value settings and post-processing could be more practicable for clinical applications.
To assess the value of model-free parameters (virtual MR elastography [vMRE] and signature-index [S-index]) derived from IVIM in evaluating pathological indicators and long-term survival in nasopharyngeal carcinoma (NPC), and to compare those with model-based parameters.
Prospective.
One hundred six patients (median: 49.5 years, 19.8% females).
FIELD STRENGTH/SEQUENCE: 3-T, IVIM, T1- and T2-weighted imaging, contrast-enhanced T1-weighted imaging.
The volumes of primary tumors were separately delineated. vMRE and S-index were calculated based on two b-values (200 and 1500 s/mm), and correlations with pathological indicators (histology, epidermal growth factor receptor [EGFR] level) were analyzed. Six types of model-based parameters were constructed using all b-values. The value in predicting overall survival (OS) and progression-free survival (PFS) was calculated. The vMRE/S-index-Clinic model and tumor-node-metastasis (TNM) staging model were constructed.
Spearman and intraclass correlation analysis (ICC), univariate and multivariate Cox analyses with seven clinical factors. Significance level: P-value < 0.05.
The median follow-up duration was 63.0 (interquartile range: 55.9, 100.3) months. All parameters showed excellent agreement (all ICC ≥ 0.790). The vMRE/S-index was significantly correlated with EGFR level and histology. Moreover, the vMRE/S-index was an independent predictor of PFS (hazard ratio [HR]: 0.639 and 2.365, respectively) and OS (HR: 0.690 and 2.116, respectively). The performance of the vMRE/S-index (C-index: 0.585 ~ 0.631) was comparable to that of the model-based parameters (C-index: 0.551 ~ 0.630). The vMRE-Clinic model (C-index: 0.700 and 0.702 for PFS and OS, respectively) and the S-index-Clinic model (C-index: 0.703 and 0.709 for PFS and OS, respectively) demonstrated superior performance compared to TNM staging model.
Model-free parameters from IVIM can predict long-term survival in NPC.
This study employed two simplified model-free parameters: the virtual MR Elastography (vMRE) to measure tissue stiffness and the signature index (S-index) to reveal the intricate tissues microstructures. These two parameters showed the comparable value in EGFR expression level and histology diagnosis as well as long-term survival prediction in nasopharyngeal carcinoma. Patients with high vMRE and low S-index value have favorable treatment outcome. Taking advantage of shorter MRI scan time and post-processing difficulty, the two model-free parameters showed good prospects in clinical application.
2 TECHNICAL EFFICACY: Stage 2.
体素内不相干运动（IVIM）是预测预后的一种有用的定量工具，但它劳动强度大。简化的b值设置和后处理对于临床应用可能更实用。
评估从IVIM得出的无模型参数（虚拟磁共振弹性成像[vMRE]和特征指数[S指数]）在评估鼻咽癌（NPC）的病理指标和长期生存中的价值，并将其与基于模型的参数进行比较。
前瞻性研究。
106例患者（中位数：49.5岁，19.8%为女性）。
场强/序列：3-T，IVIM、T1加权和T2加权成像、对比增强T1加权成像。
分别勾勒出原发肿瘤的体积。基于两个b值（200和1500 s/mm²）计算vMRE和S指数，并分析其与病理指标（组织学、表皮生长因子受体[EGFR]水平）的相关性。使用所有b值构建六种基于模型的参数。计算预测总生存（OS）和无进展生存（PFS）的价值。构建vMRE/S指数-临床模型和肿瘤-淋巴结-转移（TNM）分期模型。
Spearman检验和组内相关分析（ICC），对七个临床因素进行单因素和多因素Cox分析。显著性水平：P值<0.05。
中位随访时间为63.0（四分位间距：55.9，100.3）个月。所有参数均显示出极好的一致性（所有ICC≥0.790）。vMRE/S指数与EGFR水平和组织学显著相关。此外，vMRE/S指数分别是PFS（风险比[HR]：0.639和2.365）和OS（HR：0.690和2.116）的独立预测因子。vMRE/S指数（C指数：0.585～0.631）的性能与基于模型的参数（C指数：0.551～0.630）相当。vMRE-临床模型（PFS和OS的C指数分别为0.700和0.702）和S指数-临床模型（PFS和OS的C指数分别为0.703和0.709）与TNM分期模型相比表现出更好的性能。
IVIM的无模型参数可预测NPC的长期生存。
本研究采用了两个简化的无模型参数：用于测量组织硬度的虚拟磁共振弹性成像（vMRE）和用于揭示复杂组织微观结构的特征指数（S指数）。这两个参数在EGFR表达水平、组织学诊断以及鼻咽癌长期生存预测方面显示出相当的价值。vMRE高和S指数低的患者治疗效果良好。利用较短的MRI扫描时间和后处理难度，这两个无模型参数在临床应用中显示出良好的前景。
2 技术效能：2级
