| Objective: To evaluate the clinical significance of technetium-99m Methoxyisobutylisonitrile(99mTc-MIBI) in the differential diagnosis of thyroid nodules.Methods: 44 patients with solitary cold thyroid nodules visualized on 99mTc-pertechnetate scan were investigated. 48 hours after 99mTc-pertechnetate thyroid imaging, the anterior static images were acquired at 15min, 30min, 2h after injection of 370MBq 99mTc-MIBI. Then the nodular thyroid-to-thyroid normal tissue(T∕N) uptake ratio(UR) of the three phases and the retention index(RI) were calculated. N1 was the same side thyroid normal tissue's count and N2 was the other lobe normal tissue's count. RI was calculated using the formula : RI=(Ratio on Delayed images-Ratio on Early images) ∕Ratio on Early images. After 3 to 5 days of scintigraphy all patients underwent surgery. Finally the images were analyzed compared with the pathological results.Results: Qualitative analysis showed the sensitivity, specificity andaccuracy were 100.00％, 56.25％, 68.18％. Quantitative analysis showed the UR in 15min, 30min, 2h were higher in malignant groups than that in begin groups (P＜0.001). There were no significant differences in the RI between malignant and begin lesions (P＞0.05). And the same to T∕N1 and T∕N2(P＞0.05). If the UR of malignant groups (-S) was taken as the diagnostic threshold, the sensitivity, specificity and accuracy were 83.33％～100.00％, 81.25％～93.75％ and 86.36％～93.18％. There were no significant differences in the sensitivity between qualitative analysis and quantitative analysis(P＞0.05), but the specificity and accuracy of quantitative analyses were higher than that of qualitative analysis(P＜0.05). There were no significant differences in the sensitivity, specificity and accuracy between T∕N1 and T∕N2(P＞0.05).Conclusions: The thyroid 99mTc-MIBI imaging has clinical significance in the differential diagnosis of thyroid malignant nodules and begin lesions. And quantitative analysis is superior to qualitative analysis. |
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