From the Department of Radiology (I.J., J.M.L., J.K.H., B.I.C.) and Institute of Radiation Medicine (J.M.L., J.K.H., B.I.C.), Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.
Radiology. 2014 Aug;272(2):417-26. doi: 10.1148/radiol.14131165. Epub 2014 Apr 3.
To evaluate the diagnostic value of intravoxel incoherent motion (IVIM) diffusion-weighted (DW) magnetic resonance (MR) imaging in the quantitative assessment of the therapeutic efficacy of a vascular disrupting agent (VDA) (CKD-516) in rabbit VX2 liver tumors.
The institutional animal care and use committee approved this study. In 21 VX2 liver tumor-bearing rabbits, IVIM DW imaging examinations were serially performed with a 3.0-T imaging unit by using 12 b values from 0 to 800 sec/mm(2). The apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and blood flow-related parameter (fD*) of tumors at different time points (baseline, 4 hours, 24 hours, 3 days, and 7 days after CKD-516 administration) were compared within the treated group (n = 15) by using the Friedman test as well as between the control (n = 6) and treated groups by using the Mann-Whitney test. Correlation between the change in tumor size and IVIM DW imaging parameters was analyzed by using the Spearman rank test.
In the treated group, D* and f significantly decreased at 4 hours and then recovered to baseline at 24 hours, while D significantly increased at 24 hours (P < .005). All IVIM-derived parameters showed no significant differences between the control and treated groups at 3- and at 7-day follow-up. The greater decrease observed in f and fD* at 4 hours correlated with the smaller increase in tumor size during the 7 days of follow-up (ρ = 0.53 and 0.65, respectively; P < .05 for both).
The therapeutic effect induced by a VDA could be effectively evaluated by using IVIM DW imaging, and f and fD* may be early predictive indicators of tumor response.
评估体素内不相干运动（IVIM）扩散加权（DW）磁共振成像在定量评估血管破坏剂（VDA）（CKD-516）治疗兔 VX2 肝肿瘤疗效中的诊断价值。
本研究获得机构动物护理和使用委员会批准。在 21 只 VX2 肝肿瘤荷瘤兔中，使用 3.0T 成像仪进行 IVIM DW 成像检查，采用 12 个 b 值（0 至 800 sec/mm²）。通过 Friedman 检验比较治疗组（n = 15）不同时间点（CKD-516 给药前、给药后 4 小时、24 小时、3 天和 7 天）肿瘤的表观扩散系数（ADC）、真实扩散系数（D）、假性扩散系数（D*）、灌注分数（f）和血流相关参数（fD*），并通过 Mann-Whitney 检验比较对照组（n = 6）和治疗组之间的差异。采用 Spearman 秩检验分析肿瘤大小变化与 IVIM DW 成像参数之间的相关性。
在治疗组中，D和 f 在 4 小时时显著降低，24 小时时恢复至基线，而 D 在 24 小时时显著增加（P <.005）。在 3 天和 7 天随访时，对照组和治疗组之间所有 IVIM 衍生参数均无显著差异。在 4 小时时 f 和 fD的较大下降与在 7 天随访期间肿瘤体积的较小增加相关（ρ = 0.53 和 0.65，P <.05 均）。
IVIM DW 成像可有效评估 VDA 诱导的治疗效果，f 和 fD*可能是肿瘤反应的早期预测指标。
