99Tcm-MIBI亲肿瘤显像对甲状腺结节的诊断价值

目的:探讨99Tcm-甲氧基异丁基异睛（99Tcm-MIBI）甲状腺亲肿瘤显像对甲状腺结节良恶性的鉴别诊断价值。方法:回顾性分析165例经超声诊断为甲状腺结节，且接受手术治疗获得病理诊断的患者，所有患者先进行99TcmO4-甲状腺显像，依据图像判断“冷结节”或“凉结节”，次日进行99Tcm-MIBI甲状腺亲肿瘤显像，包括早期显像和延迟显像。以早期显像或/和延迟显像原“冷/凉结节”部位出现异常摄取，判断为阳性。并以ROI技术测定结节部位99Tcm-MIBI的摄取T/N比值。对甲状腺癌结节按长径分组，计算各组的显像阳性率。以病理结果为标准，计算99Tcm-MIBI显像检查的灵敏度、特异性、阳性预测值、阴性预测值和准确度，甲状腺癌组早期显像和延迟显像之间T/N比值的比较、甲状腺癌和甲状腺良性结节之间早期显像和延迟显像T/N比值的比较，采用t检验。不同结节大小组别之间显像阳性率的比较，采用Chi-Square检验。结果:165例患者，手术后病理证实甲状腺癌97例，甲状腺良性病变68例，99Tcm-MIBI显像对甲状腺结节的诊断灵敏度为84.5%（82/97），特异性为76.4%（52/68），阳性预测值为83.6%（82），阴性预测值为77.6%（52），准确度为81.2%（134/165）。在甲状腺癌，早期显像结节T/N比值（t=2.706 6, P<0.005）以及延迟显像T/N比值（t=2.398 1, P<0.01），均显著高于甲状腺良性病变组。甲状腺癌结节长径≥20 mm组阳性检出率74.1%，≥30 mm组为91.6%，长径≥30 mm组和20~29 mm组比较，阳性检出率未见显著性差异（[χ2]=3.575 9, P>0.05），但20~29 mm组比10~19 mm组（[χ2]=3.857 1, P<0.05）以及<10 mm组（[χ2]=8.851 7, P<0.01）阳性检出率明显提高。结论:99Tcm-MIBI甲状腺亲肿瘤显像，对甲状腺结节具有较好的诊断价值，与甲状腺良性病变比较，甲状腺癌对99Tcm-MIBI的摄取更多。当甲状腺癌结节长径大于20 mm，诊断阳性率高，结节大小是影响甲状腺癌诊断灵敏度的重要因素。

Diagnostic value of technetium-99m methoxy-isobutyl-isonitrile for thyroid nodules

Abstract: Objective To evaluate the value of radionuclide imaging with technetium-99m methoxy-isobutyl-isonitrile (99Tcm-MIBI) for the differential diagnosis of benign and malignant thyroid nodules. Methods A total of 165 patients with thyroid nodules confirmed by ultrasound and pathological diagnosis postoperatively were included in the study. All patients received 99TcmO4- thyroid imaging and the "cold or cool nodules" were judged based on the image. 99Tcm-MIBI thyroid imaging, including early imaging and delayed imaging, was performed the next day. Early imaging or/and delayed imaging showed abnormal uptake of 99Tcm-MIBI on the original "cold /cool nodules", which was assessed to be positive. The uptake T/N ratio of 99Tcm-MIBI at the nodules was determined by region-of-interest technique. Thyroid cancer nodules were grouped according to their lengths and diameters, and the positive detection rate of each group was calculated. On the basis of pathological results, the sensitivity,specificity, positive predictive value, negative predictive value and accuracy of 99Tcm-MIBI thyroid imaging were calculated. The T/N ratio of nodules between early imaging and delayed imaging in thyroid cancer group, and the T/N ratio of nodules in early imaging and delayed imaging between thyroid cancer and benign thyroid nodules were compared by t-test. The positive detection rates of different nodule size groups were compared by Chi-Square test. Results Among the 165 patients, 97 were diagnosed with thyroid cancer and 68 were diagnosed with benign thyroid nodules by postoperative pathology. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 99Tcm-MIBI imaging for thyroid nodules was 84.5%(82/97), 76.4% (52/68), 83.6%(82/98), 77.6%(52/67) and 81.2%(134/165), respectively. The T/N ratios in the early imagingand delayed imaging of thyroid cancer were significantly higher than those of benign thyroid nodules (t=2.706 6, P<0.005 t=2.398 1, P<0.01). For the thyroid cancer nodule grouped according to their lengths (≤10 mm, 10-19 mm, 20-29 mm and ≥30 mm groups), the positive detection rate of thyroid cancer nodules was 74.1% in 20-29 mm group and 91.6% in ≥30 mm group.There was no statistical differences in positive detection rate between 20-29 mm group and ≥30 mm group ([χ2]=3.575 9, P>0.05), but the positive detection rate of 20-29 mm group was significantly higher than that of 10-19 mm group ([χ2]=3.857 1, P<0.05) and that of <10 mm group ([χ2]=8.851 7, P<0.01). Conclusion 99Tcm-MIBI thyroid imaging has a good diagnostic value for thyroid nodules. Compared with benign thyroid lesions, thyroid cancer has a higher uptake of 99Tcm-MIBI. When the length of thyroid cancer nodules are greater than 20 mm, a high positive rate of diagnosis can be obtained, and the size of nodules is an important factor affecting the diagnostic sensitivity of thyroid cancer.