Department of Radiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325027, China.
Department of Oncologic Imaging, National Cancer Center, Singapore 169610 and Duke-NUS Graduate Medical School, Singapore, 169547, Singapore.
Cancer Imaging. 2021 Jan 14;21(1):12. doi: 10.1186/s40644-020-00377-0.
To compare different fitting methods for determining IVIM (Intravoxel Incoherent Motion) parameters and to determine whether the use of different IVIM fitting methods would affect differentiation of cervix cancer from normal cervix tissue.
Diffusion-weighted echo-planar imaging of 30 subjects was performed on a 3.0 T scanner with b-values of 0, 30, 100, 200, 400, 1000 s/mm. IVIM parameters were estimated using the segmented (two-step) fitting method and by simultaneous fitting of a bi-exponential function. Segmented fitting was performed using two different cut-off b-values (100 and 200 s/mm) to study possible variations due to the choice of cut-off. Friedman's test and Student's t-test were respectively used to compare IVIM parameters derived from different methods, and between cancer and normal tissues.
No significant difference was found between IVIM parameters derived from the segmented method with b-value cutoff of 200 s/mm and the simultaneous fitting method (P>0.05). Tissue diffusivity (D) and perfusion fraction (f) were significantly lower in cervix cancer than normal tissue (P< 0.05).
IVIM parameters derived using fitting methods with small cutoff b-values could be different, however, the segmented method with b-value cutoff of 200 s/mm are consistent with the simultaneous fitting method and both can be used to differentiate between cervix cancer and normal tissue.
比较不同的 IVIM（体素内不相干运动）参数拟合方法，并确定使用不同的 IVIM 拟合方法是否会影响宫颈癌与正常宫颈组织的区分。
在 3.0T 扫描仪上对 30 例受试者进行扩散加权平面回波成像，b 值分别为 0、30、100、200、400、1000s/mm。使用分段（两步）拟合法和双指数函数的同时拟合法来估计 IVIM 参数。分段拟合使用两种不同的截止 b 值（100 和 200s/mm）来研究由于截止值选择而可能产生的变化。分别使用 Friedman 检验和学生 t 检验比较不同方法得出的 IVIM 参数以及癌症组织和正常组织之间的 IVIM 参数。
截止 b 值为 200s/mm 的分段法与同时拟合法得出的 IVIM 参数无显著差异（P>0.05）。宫颈癌组织的弥散系数（D）和灌注分数（f）明显低于正常组织（P<0.05）。
使用小截止 b 值的拟合方法得出的 IVIM 参数可能不同，但截止 b 值为 200s/mm 的分段法与同时拟合法一致，两者均可用于区分宫颈癌与正常组织。
