Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.
Department of Clinical Radiology, Faculty of Medical Technology, Teikyo University, Tokyo, Japan.
Dentomaxillofac Radiol. 2021 Feb 1;50(2):20200252. doi: 10.1259/dmfr.20200252. Epub 2020 Aug 14.
This study evaluated the correlation among the diffusion-derived parameters obtained by monoexponential (ME), intravoxel incoherent motion (IVIM) and γ distribution (GD) models and compared these parameters among representative orofacial tumours.
Ninety-two patients who underwent 1.5 T MRI including diffusion-weighted imaging were included. The shape parameter (κ), scale parameter (θ), ratio of the intracellular diffusion (ƒ), extracellular diffusion (ƒ) and perfusion (ƒ) were obtained by the GD model; the true diffusion coefficient (D) and perfusion fraction (f) were obtained by the IVIM model; and the apparent diffusion coefficient (ADC) was obtained by the ME model.
ƒ had a strongly negative correlation with the ADC (ρ = -0.993) and D (ρ = -0.926). A strong positive correlation between and ƒ (ρ = 0.709) was found. Malignant lymphoma (ML) had the highest ƒ, followed by squamous cell carcinoma (SCC), malignant salivary gland tumours, pleomorphic adenoma (Pleo) and angioma. Both the IVIM and GD models suggested the highest perfusion in angioma and the lowest perfusion in ML. The GD model demonstrated a high extracellular component in Pleo and revealed that the T+T SCC group had a lower ƒ than the T+T SCC group, and poor to moderately differentiated SCC had a higher ƒ than highly differentiated SCC.
Given the correlation among the diffusion-derived parameters, the GD model might be a good alternative to the IVIM model. Furthermore, the GD model's parameters were useful for characterizing the pathological structure.
本研究评估了单指数（ME）、体素内不相干运动（IVIM）和γ分布（GD）模型得出的扩散衍生参数之间的相关性，并比较了这些参数在代表性口腔颌面肿瘤中的表现。
纳入 92 例接受 1.5T MRI 检查（包括扩散加权成像）的患者。通过 GD 模型得到形状参数（κ）、尺度参数（θ）、细胞内扩散比（ƒ）、细胞外扩散比（ƒ）和灌注比（ƒ）；通过 IVIM 模型得到真实扩散系数（D）和灌注分数（f）；通过 ME 模型得到表观扩散系数（ADC）。
ƒ与 ADC（ρ=-0.993）和 D（ρ=-0.926）呈强烈负相关。与ƒ呈强正相关（ρ=0.709）。恶性淋巴瘤（ML）的ƒ最高，其次是鳞状细胞癌（SCC）、恶性涎腺肿瘤、多形性腺瘤（Pleo）和血管瘤。IVIM 和 GD 模型均提示血管瘤的灌注最高，ML 的灌注最低。GD 模型显示 Pleo 的细胞外成分较高，并表明 T+T SCC 组的ƒ低于 T+T SCC 组，低分化 SCC 的ƒ高于高分化 SCC。
鉴于扩散衍生参数之间的相关性，GD 模型可能是 IVIM 模型的良好替代方法。此外，GD 模型的参数对于表征病理结构很有用。
