AIM: To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient (ADC) measurement and contrast-to-noise (CNR) for assessing tumor response to transarterial chemoembolization (TACE) i...AIM: To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient (ADC) measurement and contrast-to-noise (CNR) for assessing tumor response to transarterial chemoembolization (TACE) in a rabbit model. METHODS: Twelve New Zealand white rabbits bearing VX2 tumors in the liver were treated with TACE. Diffusion-weighted imaging (DWI) with various b values was performed using the same protocol before and 3 d after treatment with TACE. ADC values and CNR of each tumor pre-and post-treatment with different b factors were analyzed. Correlation between ADC values and extent of necrosis in histological specimens was analyzed by a Pearson's correlation test.RESULTS: The quality of diffusion-weighted images diminished as the b value increased. A substantial decrease in the mean lesion-to-liver CNR was observed on both pre-and post-treatment DW images, the largest difference in CNR pre-and post-treatment was manifested at a b value of 1000 s/mm2 (P = 0.036 ). The effect of therapy on diffusion early after treatment was shown by a significant increase in ADCs (P = 0.007), especially with large b factors (≥ 600 s/mm2). The mean percentage of necrotic cells present within the tumor was 76.3%-97.5%. A significant positive correlation was found between ADC values and the extent of necrosis with all b values except for b200, a higher relative coefficient between ADC values and percentage of necrosis was found on DWI with b1000 and b2000 (P= 0.002 and 0.006, respectively). CONCLUSION: An increasing b value of up to 600 s/mm2 would increase ADC contrast pre-and post-treatment, but decrease image quality. Taking into account both CNR and ADC measurement, diffusion-weighted imaging obtained with a b value of 1000 s/mm2 is recommended for monitoring early hepatic tumor response to TACE.展开更多
目的应用磁共振体素内不相干运动(intravoxel incoherent motion,IVIM)-扩散加权成像(diffusion-weighted imaging,DWI)序列联合定量非对称回波的最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo a...目的应用磁共振体素内不相干运动(intravoxel incoherent motion,IVIM)-扩散加权成像(diffusion-weighted imaging,DWI)序列联合定量非对称回波的最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence,IDEAL-IQ)测量早期活动性中轴型脊柱关节炎患者骶髂关节微循环灌注及脂肪含量变化,探讨其对早期活动性中轴型脊柱关节炎患者骶髂关节病变的临床诊断价值。方法37例早期活动性中轴型脊柱关节炎患者,均行磁共振常规T_(1)WI、T_(2)WI FSPD序列扫描,其中常规序列显示骶髂关节骨髓水肿为强直性脊柱炎阳性者29例为阳性组,强直性脊柱炎阴性者8例为阴性组,同期体检健康者20例为对照组;应用磁共振IVIM-DWI、IDEAL-IQ序列分别测量3组骶髂关节标准表观扩散系数(apparent diffusion coefficient,D_(stand))、慢速表观扩散系数(slow apparent diffusion coefficient,D_(slow))、快速表观扩散系数(fast apparent diffusion coefficient,D_(fast))、灌注分数(pseudo-diffusion coefficient,f)、骨髓脂肪分数(fat fraction,FF);绘制ROC曲线,评估磁共振IVIM-DWI、IDEAL-IQ序列D_(stand)、D_(slow)、D_(fast)、f、FF对早期活动性中轴型脊柱关节炎患者骶髂关节病变的诊断效能。结果IVIM-DWI序列显示,阳性组D_(stand)[(0.89±0.35)×10^(-3)mm^(2)/s]、D;[(0.95±0.27)×10^(-3)mm^(2)/s]、f(0.28±0.03)均高于阴性组[(0.61±0.12)×10^(-3)mm^(2)/s、(0.87±0.22)×10^(-3)mm^(2)/s、0.26±0.04]、对照组[(0.59±0.04)×10^(-3)mm^(2)/s、(0.73±0.17)×10^(-3)mm^(2)/s、0.25±0.02](P<0.05),阴性组均高于对照组(P<0.05);阳性组D;[(98.86±26.94)×10^(-3)mm^(2)/s]低于阴性组[(122.92±12.47)×10^(-3)mm^(2)/s]、对照组[(133.28±5.69)×10^(-3)mm^(2)/s](P<0.05),阴性组低于对照组(P<0.05);IDEAL-IQ序列显示,阳性组FF(38.38±13.99)低于阴性组(67.15±8.51)、对照组(62.38±8.44)(P<0.05),阴性组高于对照组(P<0.05)。D_(stand)、D_(slow)、D_(fast)、f、FF的最佳截断值分别为0.74×10^(-3)mm^(2)/s、0.67×10^(-3)mm^(2)/s、103.71×10^(-3)mm^(2)/s、0.27、57.71时,预测早期活动性中轴型脊柱关节炎患者骶髂关节病变的AUC分别为0.77(95%CI:0.65~0.86,P<0.001)、0.81(95%CI:0.70~0.89,P<0.001)、0.78(95%CI:0.67~0.87,P<0.001)、0.64(95%CI:0.52~0.75,P=0.037)、0.98(95%CI:0.91~0.99,P<0.001),灵敏度分别为65.52%、93.10%、55.17%、37.39%、96.55%,特异度分别为90.48%、61.90%、90.48%、88.10%、88.10%。结论磁共振IVIM-DWI、IDEAL-IQ序列可定量分析早期活动性中轴型脊柱关节炎患者骶髂关节微循环灌注及脂肪含量的变化,D_(stand)、D_(slow)、D_(fast)、FF对早期活动性中轴型脊柱关节炎患者骶髂关节病变有较高诊断价值。展开更多
基金The National Natural Science Foundation of China, NO. 30470503The Key Program of Shanghai Science and Technology Commission, NO. 04JC14074The Foundation of Shanghai Educational commission, NO. 03J405037
文摘AIM: To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient (ADC) measurement and contrast-to-noise (CNR) for assessing tumor response to transarterial chemoembolization (TACE) in a rabbit model. METHODS: Twelve New Zealand white rabbits bearing VX2 tumors in the liver were treated with TACE. Diffusion-weighted imaging (DWI) with various b values was performed using the same protocol before and 3 d after treatment with TACE. ADC values and CNR of each tumor pre-and post-treatment with different b factors were analyzed. Correlation between ADC values and extent of necrosis in histological specimens was analyzed by a Pearson's correlation test.RESULTS: The quality of diffusion-weighted images diminished as the b value increased. A substantial decrease in the mean lesion-to-liver CNR was observed on both pre-and post-treatment DW images, the largest difference in CNR pre-and post-treatment was manifested at a b value of 1000 s/mm2 (P = 0.036 ). The effect of therapy on diffusion early after treatment was shown by a significant increase in ADCs (P = 0.007), especially with large b factors (≥ 600 s/mm2). The mean percentage of necrotic cells present within the tumor was 76.3%-97.5%. A significant positive correlation was found between ADC values and the extent of necrosis with all b values except for b200, a higher relative coefficient between ADC values and percentage of necrosis was found on DWI with b1000 and b2000 (P= 0.002 and 0.006, respectively). CONCLUSION: An increasing b value of up to 600 s/mm2 would increase ADC contrast pre-and post-treatment, but decrease image quality. Taking into account both CNR and ADC measurement, diffusion-weighted imaging obtained with a b value of 1000 s/mm2 is recommended for monitoring early hepatic tumor response to TACE.
文摘目的应用磁共振体素内不相干运动(intravoxel incoherent motion,IVIM)-扩散加权成像(diffusion-weighted imaging,DWI)序列联合定量非对称回波的最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence,IDEAL-IQ)测量早期活动性中轴型脊柱关节炎患者骶髂关节微循环灌注及脂肪含量变化,探讨其对早期活动性中轴型脊柱关节炎患者骶髂关节病变的临床诊断价值。方法37例早期活动性中轴型脊柱关节炎患者,均行磁共振常规T_(1)WI、T_(2)WI FSPD序列扫描,其中常规序列显示骶髂关节骨髓水肿为强直性脊柱炎阳性者29例为阳性组,强直性脊柱炎阴性者8例为阴性组,同期体检健康者20例为对照组;应用磁共振IVIM-DWI、IDEAL-IQ序列分别测量3组骶髂关节标准表观扩散系数(apparent diffusion coefficient,D_(stand))、慢速表观扩散系数(slow apparent diffusion coefficient,D_(slow))、快速表观扩散系数(fast apparent diffusion coefficient,D_(fast))、灌注分数(pseudo-diffusion coefficient,f)、骨髓脂肪分数(fat fraction,FF);绘制ROC曲线,评估磁共振IVIM-DWI、IDEAL-IQ序列D_(stand)、D_(slow)、D_(fast)、f、FF对早期活动性中轴型脊柱关节炎患者骶髂关节病变的诊断效能。结果IVIM-DWI序列显示,阳性组D_(stand)[(0.89±0.35)×10^(-3)mm^(2)/s]、D;[(0.95±0.27)×10^(-3)mm^(2)/s]、f(0.28±0.03)均高于阴性组[(0.61±0.12)×10^(-3)mm^(2)/s、(0.87±0.22)×10^(-3)mm^(2)/s、0.26±0.04]、对照组[(0.59±0.04)×10^(-3)mm^(2)/s、(0.73±0.17)×10^(-3)mm^(2)/s、0.25±0.02](P<0.05),阴性组均高于对照组(P<0.05);阳性组D;[(98.86±26.94)×10^(-3)mm^(2)/s]低于阴性组[(122.92±12.47)×10^(-3)mm^(2)/s]、对照组[(133.28±5.69)×10^(-3)mm^(2)/s](P<0.05),阴性组低于对照组(P<0.05);IDEAL-IQ序列显示,阳性组FF(38.38±13.99)低于阴性组(67.15±8.51)、对照组(62.38±8.44)(P<0.05),阴性组高于对照组(P<0.05)。D_(stand)、D_(slow)、D_(fast)、f、FF的最佳截断值分别为0.74×10^(-3)mm^(2)/s、0.67×10^(-3)mm^(2)/s、103.71×10^(-3)mm^(2)/s、0.27、57.71时,预测早期活动性中轴型脊柱关节炎患者骶髂关节病变的AUC分别为0.77(95%CI:0.65~0.86,P<0.001)、0.81(95%CI:0.70~0.89,P<0.001)、0.78(95%CI:0.67~0.87,P<0.001)、0.64(95%CI:0.52~0.75,P=0.037)、0.98(95%CI:0.91~0.99,P<0.001),灵敏度分别为65.52%、93.10%、55.17%、37.39%、96.55%,特异度分别为90.48%、61.90%、90.48%、88.10%、88.10%。结论磁共振IVIM-DWI、IDEAL-IQ序列可定量分析早期活动性中轴型脊柱关节炎患者骶髂关节微循环灌注及脂肪含量的变化,D_(stand)、D_(slow)、D_(fast)、FF对早期活动性中轴型脊柱关节炎患者骶髂关节病变有较高诊断价值。
