Objective:To explore the value of multi-parametric MRI for thyroid gland in differentiating benign and malignant thyroid nodules.Methods:From December 2018 to May 2020, 78 patients with 91 post-surgically pathologically confirmed thyroid nodules were enrolled in Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. For each patient, the following MRI findings were obtained including the nodules′ location, size, shape, margin, signal intensity, cystic change, degree and pattern of contrast enhancement, involvement of surrounding structure, and ADC values. The time-intensity curve (TIC) were plotted and subtyped based on dynamic contrast enhancement MRI. The MRI findings between the benign and malignant thyroid nodules were compared using Mann-Whitney U test, χ 2 test or Fisher exact test. Multiple logistic regression analysis was used to select independent predictive variables and build a combined model, and the ROC curve was used to evaluate the diagnostic performance of each MRI finding and the combined model. Results:Between the benign and malignant thyroid nodules, the significant differences were found in size, shape, margin, presence of cystic changes, T 1WI signal intensity, ADC value, enhancement homogeneity, TIC subtypes and presence of thyroid capsule involvement ( P<0.05). Multivariate logistic analysis showed that ill-defined margin (OR=77.61), no presence of cystic changes (OR=36.11) and difference between TIC subtypes (OR=83.41) were independent predictive variables, and the area under the ROC curve (AUC) was 0.879, 0.788, and 0.751, respectively. The AUC, sensitivity and specificity of the combined model were 0.977, 0.986, and 0.904, respectively. Conclusions:Thyroid multi-parametric MRI derived findings can be used for the differential diagnosis of benign and malignant nodules. Combined with the independent risk factors with ill-defined margin, no presence of cystic changes, TIC of type plateau or washout, the diagnostic model has a higher diagnostic efficiency.

目的 与甲状腺超声检查对比,评估使用8通道甲状腺专用表面线圈进行磁共振检查的价值.方法 前瞻性对49名健康志愿者行甲状腺磁共振和超声检查,磁共振检查采用8通道甲状腺专用表面线圈.以超声检查结果为金标准,分别从结节数目、大小、位置、性质多方面评估磁共振对甲状腺结节的检查价值,将甲状腺超声检出的结节分为长径≤3 mm、3mm＜长径＜10 mm、长径≥10 mm三组,分析磁共振对不同组别甲状腺结节的检出效能.结果 甲状腺超声检查,49名志愿者中共有23名检出30个结节,MR检出其中21名的27个结节,结节检出率为90％.MR分别检出超声所检出长径≤3 mm、3 mm＜长径＜10 mm、长径≥10 mm三组结节11个、15个、4个中的9个(81.82％)、14个(93.33％)、4个(100％).对于甲状腺超声和磁共振均检出的27个结节,甲状腺超声检查长径、短径平均分别为6.17 mm、3.76 mm,MR检查长径、短径平均分别为5.58 mm、3.91 mm,两种检查方式长径和短径的差异均没有统计学意义;在结节性质方面,磁共振检出的27个结节中有26个性质和超声是一致的,其余1个结节,超声诊断为囊实性,而磁共振诊断为囊性.结论 与甲状腺超声检查相比,使用8通道甲状腺专用表面线圈进行磁共振扫描,在结节数目、大小、位置以及性质方面均具有明显的一致性.

目的 探讨采用甲状腺专用表面线圈的术前多参数MRI特征对甲状腺癌区域淋巴结转移的预测价值.材料与方法 回顾性分析中国医学科学院肿瘤医院深圳医院经手术病理证实的甲状腺癌51例,均行甲状腺病灶切除及颈部淋巴结清扫,术前均行3.0 T增强MRI扫描.以术后病理为对照,分析比较转移淋巴结和非转移淋巴结的MRI征象,构建转移淋巴结的预测模型.计量资料的比较采用t检验或U检验,计数资料比较采用χ2检验,多元逻辑回归分析用于构建预测模型,ROC曲线用于评估预测模型的诊断效能.结果 51例甲状腺癌患者共135枚淋巴结纳入研究,其中转移淋巴结74枚,非转移淋巴结61枚.转移与非转移淋巴结的长短径、ADC值、T1WI和抑脂T2WI信号、形状、边缘、是否囊变、强化程度等差异具有统计学意义(P均<0.05).其中抑脂T2WI呈混杂信号、明显强化、低ADC值(<0.91×10-3 mm2/s)是转移淋巴结的独立预测因子,联合这3个MRI征象所建立的预测模型其AUC为0.93,敏感度为82.4％,特异度为88.5％.甲状腺癌伴有桥本氏甲状腺炎时,其Ⅵ区非转移淋巴结的长径、短径均大于不伴桥本氏甲状腺炎组(P<0.05).结论 术前多参数MRI特征对甲状腺癌区域淋巴结转移有较高的预测价值,转移淋巴结多表现为抑脂T2WI呈混杂信号、明显强化、更低的ADC值,为甲状腺癌的术前临床决策提供非常有价值的依据.

目的 探讨8通道特制甲状腺专用表面线圈对甲状腺磁共振检查图像质量的影响.材料与方法 对49名健康志愿者使用8通道甲状腺专用表面线圈行甲状腺磁共振检查,扫描序列包括T1WI、T2WI、T2WI-FS(fat-suturation)、扩散加权成像(diffusion weighted imaging,DWI)-STIR和DWI-FOCUS.然后对图像质量进行主观评价和客观评价,主观评价为由两名影像诊断经验丰富的医师依据Likert Scale评分法对图像质量进行双盲评价,并对评分结果进行一致性分析.客观评价为测量不同序列图像甲状腺组织的信号强度、信噪比和对比噪声比,并对左右叶甲状腺组织的一致性进行分析.结果 基于主观评分标准,两名评分者评分结果为:T1WI、T2WI和T2WI-FS评分均达到4分以上,DWI-STIR和DWI-FOCUS序列均达到3分以上,二者对T1WI、T2WI、T2WI-FS、DWI-STIR和DWI-FOCUS各序列评分一致性分别为0.92、0.94、0.96、0.93和0.89.基于客观评价,T1WI、T2WI、T2WI-FS、DWI-STIR和DWI-FOCUS各序列甲状腺组织信号强度分别为1246.39、1345.03、860.88、236.91和569.06,左右叶一致性分别为0.957、0.937、0.924、0.871和0.848.各序列甲状腺组织信噪比分别为17.56、33.18、42.82、27.99和19.53,左右叶一致性分别为0.945、0.957、0.885、0.825和0.773.各序列甲状腺组织对比噪声比分别为0.20、5.36、3.07、16.01和9.91,左右叶一致性分别为0.577、0.704、0.740、0.710和0.589.结论 使用甲状腺专用表面线圈扫描图像主观评分高,信号均匀,信号强度、信噪比以及对比噪声比高,可以满足诊断要求.

目的探讨动态对比增强磁共振成像(dynamic contrast-enhanced MRI,DCE-MRI)的定量及半定量参数在鉴别甲状腺良恶性结节中的诊断效能.材料与方法回顾性分析经手术病理证实的甲状腺结节患者45例,术前均行颈部DCE-MRI增强检查,获取定量参数:容积转运常数(volume transfer constant,Ktrans)、速率常数(rate constant,Kep)、血管外细胞外容积分数(extravascular extracellular volume fraction,Ve)和非定量参数:增强曲线下初始面积(initial area under the gadolinium curve,IAUGC)、最大增强斜率(maximum slope of increase,Max Slope)、对比增强比率(contrast enhancement rate,CER)以及时间-信号曲线(time-intensity curves,TIC);应用Mann-Whitney U检验及Fisher检验分析两组间连续变量和分类变量是否有统计学差异,并通过绘制ROC曲线来评价DCE-MRI中的各参数在鉴别甲状腺良恶性结节方面的诊断效能.结果在45例甲状腺结节患者中,良性结节12个(良性组),恶性结节34个(恶性组),良性结节:平均Kep、Ktrans、Ve值分别为(3.63±2.83)min?1、(1.41±1.01)min?1、(0.48±0.19)min?1;恶性结节分别为(2.70±2.42)min?1、(1.23±1.23)min?1、(0.51±0.22)min?1,两组之间差异无统计学意义(P值均>0.05);良性结节:Max Slope、CER、IAUGC值分别为(0.10±0.10)s、(2.04±0.67)s、(0.78±0.38)s,恶性结节分别为(0.07±0.10)s、(1.55±0.67)s、(0.94±0.67)s,且两组间CER值差异有统计学差异(P<0.05),其对于区分良恶性结节的最佳特异度、敏感度分别为0.75、0.62,ROC曲线下面积AUC为0.72.TIC曲线显示甲状腺恶性结节多表现为Ⅱ型曲线,良性结节多表现为Ⅲ型曲线,且差异具有统计学意义(P=0.02).结论DCE-MRI中的半定量参数(CER)及TIC曲线类型对鉴别甲状腺良恶性结节有一定的诊断效能,初步数据显示基于DCE-MRI的定量参数在鉴别甲状腺良恶性结节方面价值有限,尚需要更大样本研究证实.

Objective:To investigate the feasibility and reproducibility of using three-dimensional arterial spin labeling (3D-ASL) technique to evaluate the thyroid blood flow (TBF) in healthy adults and compare the difference in TBF between subjects with different gender and age.Methods:In this prospective study, 100 healthy adult subjects were enrolled from November 2018 to June 2019 in Chinese Academy of Medical Sciences Cancer Hospital, Shenzhen Hospital. All subjects received thyroid 3D-ASL MRI scanning, but several subjects were excluded from analysis for reasons including intolerance to examination ( n=1), overt artifacts ( n=11), abnormality detected in thyroid gland during conventional MRI ( n=15), resulting in 73 subjects included. Two attending radiologists independently evaluated the quality of ASL images and measured the TBF in upper, middle and lower poles of each lobe in thyroid gland bilaterally. Cohen’s Kappa was used to test the agreement in image quality between 2 radiologists, while intraclass correlation (ICC) analysis was implemented to evaluate the consistency in TBF measurements. Univariate variance analysis was used to compare the TBF in upper, middle and lower pole of thyroid gland unilaterally, and student t-test was performed to test the difference in TBF between two lobes, or in the same lobe but between different gender or age groups. Results:For image quality, 2 radiologists have good agreement (Kappa=0.753, P<0.001). In terms of TBF, consistency was moderate in the lower pole of left lobe between 2 radiologists (ICC=0.648, P<0.001), but good in the remaining parts of thyroid gland (all ICC>0.75, P<0.001). Unilaterally, TBF in the middle pole was significantly higher than those in the upper or lower pole ( P<0.001), but no significant difference was found between the upper and lower pole ( P>0.05). Regardless of upper, middle or lower pole, TBF in the right lobe was higher than the counterpart in the left lobe ( t=6.182, 6.294, 4.896, P<0.001). Between male subjects ( n=31) and female subjects ( n=42), no significant difference was found in the corresponding upper, middle or lower pole of thyroid lobe unilaterally ( P>0.05). As for age group, TBF in the middle pole of thyroid gland was higher in the middle age group (45-59 years old, n=12) than that in the young adult group (18-44 years old, n=61) ( t=3.868, P=0.003 for the left lobe, and t=2.647, P=0.022 for the right lobe), but no significant difference was found in the upper or lower pole of the unilateral thyroid lobe ( P>0.05). Conclusion:ASL can accurately measure blood flow perfusion in the thyroid gland with good reproducibility.