使用磁振造影IVIM技術比較甲狀腺結節經TAE治療前後的變化

研究目的 使用體素內不同調運動(Intravoxel incoherent motion, IVIM) 磁振造影技術來評估甲狀腺結節病人經甲狀腺動脈栓塞術（Thyroid Artery Embolization,TAE）治療前後影像微結構與微血流之變化。材料與方法 本研究納入20名甲狀腺結節病人，於 TAE 治療前、治療後及治療後一個月進行 3T MRI 掃描。根據結節體積縮小率（Volume Reduction Ratio, VRR）進行分組，其中VRR ≥ 50%組8名，年齡中位數為43.5歲（IQR：38.75–47.25），12名為VRR<50%組，年齡中位數為40.50歲(IQR：30.75-48.75)。手動 ROI 於 T2權重影像上繪製，計算每位病患的 D、D*、f 值中位數與 ROI 體積。統計分析採用 Mann-Whitney U 檢定比較VRR≥50%組和VRR<50%組IVIM 參數的差異，並以 Kruskal-Wallis 檢定分析不同時間點 IVIM 參數的變化。結果 病人經TAE後VRR≥50%組和VRR<50%組的normalized f值有顯著差異（p <0.05），代表治療後的normalized f值會影響到治療後一個月體積縮小的比例。治療後一個月VRR≥50%組和VRR<50%組的D值有顯著差異（p <0.05），可能是由於缺血，組織修復的差異、細胞脫水以及纖維化的程度不同所致。VRR < 50% 組中，D 與 normalized D 在不同時間點間皆呈現顯著變化（p < 0.05），其中 post hoc 分析顯示 D 值在治療後與 1 個月間，normalized D 則在治療前和治療後以及治療後與治療後1個月之間有顯著差異。此外，還進行了ROC曲線分析，以評估治療後的IVIM參數是否能有效預測一個月的治療效果，結果顯示，normalized f在區分 VRR ≥ 50% 與 VRR < 50% 兩組別上表現最為突出，其曲線下面積(Area Under the Curve ,AUC)達 0.885。結論 本研究初步顯示，IVIM磁振造影技術可以反應甲狀腺結節在TAE 治療前後組織微環境之變化， 其中normalized f 值上升可能與一個月治療效果較差有關，normalized f值的ROC分析可提供最佳的甲狀腺結節體積縮減預測。

Purpose Intravoxel incoherent motion (IVIM) magnetic resonance imaging was used to evaluate the changes in imaging microstructure and microvascular flow in patients with thyroid nodules before and after thyroid artery embolization (TAE).Materials and Methods This study included 20 patients with thyroid nodules who underwent 3T MRI scans before, after, and one month after TAE treatment. The patients were divided into groups according to the volume reduction ratio (VRR), including 8 patients in the VRR ≥ 50% group with a median age of 43.5 years (IQR: 38.75–47.25) and 12 patients in the VRR < 50% group with a median age of 40.50 years (IQR: 30.75-48.75). ROIs were manually drawn on T2-weighted images, and the median D, D*, f values, and ROI volume of each patient were calculated. Statistical analysis The Mann-Whitney U test was used to compare the differences in IVIM parameters between the VRR ≥ 50% group and the VRR < 50% group, and the Kruskal-Wallis test was used to analyze the changes in IVIM parameters at different time points.Results There was a significant difference in the normalized f value between the VRR ≥ 50% group and the VRR < 50% group after TAE (p < 0.05), indicating that the normalized f value after treatment will affect the proportion of volume reduction one month after treatment. There was a significant difference in the D value between the VRR ≥ 50% group and the VRR < 50% group one month after treatment (p < 0.05), which may be due to ischemia, differences in tissue repair, cell dehydration, and different degrees of fibrosis. In the VRR < 50% group, D and normalized D showed significant changes at different time points (p < 0.05), among which post hoc analysis showed that D values were significantly different between after treatment and 1 month, and normalized D was significantly different between before and after treatment and between after treatment and 1 month after treatment. In addition, ROC curve analysis was performed to evaluate whether the IVIM parameters after treatment can effectively predict the treatment effect at one month. The results showed that normalized f performed best in distinguishing the two groups of VRR ≥ 50% and VRR < 50%, and its area under the curve (AUC) reached 0.885.ConclusionThis study preliminarily showed that IVIM magnetic resonance imaging technology can reflect the changes in the tissue microenvironment of thyroid nodules before and after TAE treatment. Among them, the increase in normalized f value may be related to the poor treatment effect at one month. ROC analysis of normalized f value can provide the best prediction of thyroid nodule volume reduction.