Correlation Between ^99mTc-MIBI Imaging And ¹³¹I Whole Body Imaging In Patients With Lung Metastasis Of Differentiated Thyroid Carcinoma

ObjectiveTo compare the results of ^99mTc-methoxyisobutylisonitrile(^99mTc-MIBI)imaging and ¹³¹I whole body scan(¹³¹I-WBS)in patients with lung metastasis from differentiated thyroid cancer（DTC）,objective to explore the application value of ^99mTc-MIBI imaging results in patients with DTC lung metastasis after radioiodine therapy.Methods120 patients with lung metastases of DTC treated with radioiodine in our department were retrospectively analyzed.The patients with lung metastases of DTC were treated with radioiodine for the first time.Six months after the residual thyroid tissue was removed,^99mTc MIBI imaging was performed.The next day,¹³¹I（150-220mci）was taken.Five days later,¹³¹I whole body imaging was performed,the patients were divided into four groups:^99mTc-MIBI imaging positive group and ¹³¹I whole body imaging positive group（group A）;^99mTc-MIBI imaging positive,¹³¹I whole body imaging negative group（group B）;^99mTc-MIBI imaging was negative,¹³¹I whole body imaging was positive（Group C）;^99mTc-MIBI imaging negative,¹³¹I whole body imaging negative group（Group D）.Spearman rank sum correlation was used to analyze the correlation between ^99mTc-MIBI imaging and ¹³¹I whole body imaging.Combined with thyroglobulin（Tg）,the results of ^99mTc-MIBI imaging and ¹³¹I whole body imaging were compared to further explore the application value of ^99mTc-MIBI imaging in patients with DTC lung metastasis after radioiodine therapy.Results1.The imaging results of 120 patients were finally included.There were 106 positive cases(indicating that ^99mTc-MIBI imaging was positive and/or ¹³¹I whole body imaging was positive),including 28 positive cases of ^99mTc-MIBI imaging and 90 positive cases of ¹³¹I whole body imaging.The sensitivity of ^99mTc-MIBI imaging in finding positive cases was significantly lower than that of ¹³¹I whole body imaging（χ²=12.6,P<0.05）.2.Imaging results of four groups:group A,n=12;Group B,n=16;Group C,n=78;Group D,n=14.Spearman rank sum correlation test showed that there was a moderate negative correlation between the two imaging results,and the correlation coefficient was r_s=-0.410（P<0.0001）.3.There was significant difference in Tg value among the four groups（H=20.526,P<0.001）.The rank sum pairwise comparison of significance level corrected by Bonferroni method showed that there was significant difference in TG value between"all positive group"and"MIBI^-、¹³¹I⁺"group（adjusted P=0.002）,"MIBI⁺、¹³¹I^-"and"MIBI^-、¹³¹I⁺"group（adjusted P=0.011）,but there was no significant difference among other groups.The level of Tg in patients with positive ^99mTc-MIBI was significantly higher than that in patients with negative ^99mTc-MIBI and positive ¹³¹I whole body imaging（P<0.05）.Spearman rank correlation analysis was used to analyze the correlation of Tg levels between positive and negative ^99mTc-MIBI imaging groups.The results showed that^99mTc-MIBI imaging was moderately positively correlated with Tg levels,and the correlation coefficient was r_s=0.402（P<0.0001）.Conclusion1.The combination of ^99mTc-MIBI imaging and ¹³¹I whole body imaging can better evaluate the lung metastasis of DTC patients with lung metastasis.2.^99mTc-MIBI imaging results were correlated with serum Tg level.