超声结合增强CT对甲状腺癌术后局部复发／残留的诊断价值

The role of combination of ultrasonography and contrast-enhanced CT in diagnosis of recurrent/residual cancer after thyroidectomy

目的对比分析甲状腺癌术后局部复发／残留的高频彩色多普勒超声与增强CT表现，探讨超声、增强CT及二者结合对甲状腺癌术后局部复发／残留的诊断符合率。方法回顾性分析46例经手术病理证实的甲状腺癌术后局部复发／残留患者同期高频彩色多普勒超声与增强CT影像学资料及诊断符合率。结果甲状腺癌术后复发／残留时间7d～10年，平均（14．6±12．1）月。局部复发／残留结节20例，大小0．5～4．6cm，平均2．1cm，超声声像图以低回声实性结节为主（60％），砂粒样钙化占40％。颈部淋巴结转移40例，以Ⅵ区为主（75％），超声检出最小转移性淋巴结3mm；40例中12例（30％）伴液化囊性变，10例（25％）伴点状钙化，5例（12．5％）同时合并钙化及囊性变，结内微钙化、囊性变及高回声等为特异性表现。超声及增强CT对局部复发／残留结节检出率均为90％，颈部淋巴结转移检出率分别为80％和72．5％。超声与增强CT对局部复发／残留结节、颈部淋巴结及总诊断率分别为65％、67．5％和65．2％对75％、55％和65．2％，二者联合诊断率为86．4％、77．5％和91．3％，与单纯高频彩色多普勒超声及增强CT相比，差异有统计学意义（P〈0．05）。结论高频彩色多普勒超声可作为甲状腺癌术后随访的首选影像学检查方法之一，联合增强CT可进一步提高诊断符合率。

Objective To analyze the findings of recurrent/residual caner after thyroidectomy for thyroid cancer in both ultrasonography （US） and contrast-enhanced CT （CECT）, and to assess the diagnostic value of combination of these two modalities. Methods Forty-six patients with recurrence/ residue of thyroid cancer underwent both high-frequency US and CECT examinations and were enrolled in this study. The imaging features on US and CECT were reviewed and diagnostic accuracies for local residual lesions and cervical lymph node metastasis were evaluated according to pathological results. Results In 46 patients, the average period between thyroidectomy and diagnosis of recurrent/residual cancer was （14.6±12.1 ）months（range,7 days- 10 years）. Twenty patients had local recurrent tumors at the surgical bed and the average size of tumors was 2.1 em（range,0.5 - 4.6 cm）. On US finding,the recurrent/residual tumors were hypoechoic in 60 % of eases, had microealeification in 40 %. Cervical lymph node metastasis were found in 40 patients,and 75% of them were located in zone gI. The smallest size of abnormal lymph node which can be detected by US was 3 ram. In cases of lymph node metastasis, 12 cases （30%/40） became cystic, 10 （25 %） presented microcalcifications,and 5 （12.5 %） showed microcalcifications and cystic change within a lymph node. Microcalcifications,cystic change and hyperechoic appearance within a lymph node suggested malignant. The detection rate of US and CECT in the local recurrent/residual cancer were 90% and 90%, respectively. The detection rate of cervical lymph nodes metastasis were 80 % and 72.5 %, respectively. The diagnostic accuracy of US and CECT in local recurrence, cervical lymph node metastasis and both were 65%,67.5% and 65.2% vs 75%, 55% and 65.2%, respectively （ P 〉 0.05 for all comparisons）, the diagnostic accuracy of combination of US and CECT were increased to 86.4%, 77.5% and 91.3%, respectively. US combined with CECT significantly improved the diagnostic capability compared with US or CECT alone（ P 〈0.05）. Conclusions US should be used as the first choice of imaging examination for post-thyroidectomy of thyroid cancer. US combined with CECT could further increase the diagnostic accuracy in recurrent/residual thyroid cancer.