Department of Radiology, University Paris Diderot, Sorbonne Paris Cité, France.
Radiology. 2012 Aug;264(2):464-72. doi: 10.1148/radiol.12111530. Epub 2012 Jun 12.
To determine if diffusion-weighted (DW) magnetic resonance (MR) imaging with measurements of the apparent diffusion coefficient (ADC), pure diffusion coefficient, perfusion-related diffusion coefficient, and perfusion fraction can be used to differentiate between viable tumor and fibrous and necrotic regions within malignant liver tumors.
The prospective study was approved by the institutional review board, and informed consent was obtained from all patients. Forty-eight patients with 51 malignant tumors were assessed. MR images of the liver were obtained by using DW imaging with 11 b factors (0-500 sec/mm(2)) and gadolinium-enhanced three-dimensional gradient-echo T1-weighted imaging. Tumors were segmented into viable tumor and fibrous and necrotic regions according to the enhancement pattern after injection of a nonspecific gadolinium chelate and, in surgically removed lesions, results of histopathologic correlation. The ADC, pure diffusion coefficient, perfusion-related diffusion coefficient, and perfusion fraction were calculated, and values were compared between viable tumor and fibrous and necrotic regions with the Kruskal-Wallis test followed by the Dunn multiple comparison test.
The pure diffusion coefficient differed significantly between regions of viable tumor tissue and fibrosis (1.16 × 10(-3) mm(2)/sec ± 0.29 and 1.48 × 10(-3) mm(2)/sec ± 0.31, respectively; P = .016) and between regions of viable tumor tissue and necrosis (1.70 × 10(-3) mm(2)/sec ± 0.49, P = .002). There was a significantly lower perfusion fraction in necrotic regions (14% ± 6) than in viable tumor regions (21% ± 8, P = .005), but the perfusion fraction of the fibrous regions (21% ± 7) did not differ significantly from that of the other two regions. ADCs and perfusion-related diffusion coefficients did not differ significantly among the three regions.
Results of this study show that viable tumor regions in malignant liver tumors can be differentiated from fibrous and necrotic regions with use of the pure diffusion coefficient but not with the other diffusion parameters.
旨在确定磁共振弥散加权成像（DWI）测量表观弥散系数（ADC）、纯弥散系数、灌注相关弥散系数和灌注分数是否可用于鉴别恶性肝肿瘤中的存活肿瘤与纤维和坏死区域。
本前瞻性研究经机构审查委员会批准，并获得所有患者的知情同意。对 48 例 51 个恶性肿瘤患者进行了评估。采用 11 个 b 值（0-500 sec/mm²）的 DWI 和钆增强三维梯度回波 T1 加权成像获得肝脏 MR 图像。根据注射非特异性顺磁螯合物后的增强模式以及手术切除病变的组织病理学相关性，将肿瘤分为存活肿瘤、纤维和坏死区域。计算 ADC、纯弥散系数、灌注相关弥散系数和灌注分数，并采用 Kruskal-Wallis 检验和 Dunn 多重比较检验比较存活肿瘤与纤维和坏死区域之间的各参数值。
存活肿瘤组织区域与纤维化区域的纯弥散系数（分别为 1.16×10⁻³mm²/sec±0.29 和 1.48×10⁻³mm²/sec±0.31）之间差异有统计学意义（P =.016），存活肿瘤组织区域与坏死区域的纯弥散系数（1.70×10⁻³mm²/sec±0.49）之间差异也有统计学意义（P =.002）。坏死区域的灌注分数（14%±6）明显低于存活肿瘤区域（21%±8，P =.005），但纤维区域的灌注分数（21%±7）与其他两个区域之间差异无统计学意义。ADC 和灌注相关弥散系数在 3 个区域之间差异无统计学意义。
本研究结果表明，恶性肝肿瘤中的存活肿瘤区域可通过纯弥散系数而不是其他弥散参数与纤维和坏死区域进行区分。
