^131I治疗后单光子发射计算机断层成像术与多层螺旋CT同机融合显像诊断甲状腺癌术后肺转移的价值

Diagnostic value of therapeutic dose ^131I-SPECT/CT fusion imaging for the postoperative pulmonary metastasis of thyroid carcinoma

目的探讨甲状腺癌术后治疗剂量^131I-单光子发射计算机断层成像术与多层螺旋cT断层融合显像（Rx ^131I-SPECT／CT）诊断肺转移的价值，并与治疗剂量^131I-全身扫描（Rxn-I-WBS）比较。方法回顾性分析18例甲状腺癌术后血清甲状腺球蛋白（Tg）水平增高、临床拟诊为肺转移患者的Rx ^131I-WBS和肺部Rx ^131I-SPECT／CT显像结果，分析转移灶的CT特征和摄碘程度，比较RxntI-SPECT／CT与Rx ^131I-WBS诊断甲状腺癌肺部转移灶的准确性及其增益作用。结果18例拟诊甲状腺癌术后肺转移患者最终临床及随访证实15例为肺转移，Rx ^131I-WBS正确诊断、假阳性、假阴性分别有12、5、1例，Rx ^131I-SPECT／CT分别有18、0、0例，二者诊断准确率分别为66．7％（12／18）和100％（18／18），差异有统计学意义（P〈0．05）。15例甲状腺癌术后肺转移患者血清Tg为（541．5±274．3）ng／ml，Rx ^131I-WBS和Rx ^131I-SPECT／CT分别发现30个和46个肺转移灶；3例无肺转移患者Rx ^131I-WBS和Rx ^131I-SPECT／CT分别发现5个和7个病灶。15例甲状腺癌术后肺转移和3例无肺转移者肺部病灶平均浓聚^131I分别为（368．25±354.31）kBq和（5．87±6．97）kBq。结论Rx ^131I-SPECT／CT诊断甲状腺癌术后肺转移准确率高，其定位、定性肺转移灶较^131I-WBS有明显优势，可发现隐匿性病灶并提供转移灶^131I摄取程度及形态学信息。对于血清Tg升高、Rx ^131I-WBS无法确定或定位的肺部病灶，进一步行肺胁^131I—SPECT／CT有助于病情评估和术后分期。

Objective To explore diagnostic value of therapeutic dose ^131I-SPECT/CT fusion imaging （Rx ^131I-SPECT/CT） for the pulmonary metastasis of postoperative thyroid cancer, and to compare with therapeutic doses ^131I-whole body scan （Rx ^131I-WBS）. Methods The Rx ^131I-WBS and lung Rx ^131I-SPECT/CT findings in 18 patients who were suspected pulmonary metastasis of postoperative thyroid cancer with serum thyroglobulin （Tg） levels increased were retrospectively analyzed on the CT features and the iodine intake degree of the pulmonary lesions. The accuracy and the incremental value of the diagnosis for pulmonary metastases by Rx ^131I-WBS and lung Rx ^131I-SPECT/CT were compared. Results Among 18 patients, 15 cases pulmonary metastasis of postoperative thyroid carcinoma were confirmed by the final clinical diagnosis and follow-up. 12 cases, 5 cases and 1 case were diagnostic accuracy, false positives, and false negatives by Rx ^131I-WBS, respectively, and 18 cases, 0 case and 0 case by Rx ^131I-SPECT/CT, respectively. The diagnostic accuracy rates of Rx ^131I-WBS and Rx ^131I-SPECT/CT were 66.7 % （12/18） and 100 % （18/18）, respectively （P 〈 0.05）. In 15 patients with pulmonary metastasis, serum thyroglobulin （Tg） was （541.5±274.3） ng/ml, and 30 and 46 pulmonary metastases were found by Rx ^131I-WBS and Rx ^131I-SPECT/CT, respectively. 5 and 7 pulmonary lesions were found by Rx ^131I-WBS and Rx ^131I-SPECT/CT in 3 cases of pulmonary non-metastases, respectively. The mean degrees of iodine intake in pulmonary lesions were （368.25±354.31） kBq and （5.87± 6.97） kBq in 15 patients with pulmonary metastasis and 3 patients without pulmonary metastasis, respectively. Conclusions Rx ^131I-SPECT/CT fusion imaging has a high identification accuracy for the diagnosis of pulmonary metastasis of postoperative thyroid carcinoma, featured by the better localization and qualitative diagnosis compared with ^131I-WBS, and it could detect occult lesions to provide the degree of iodine intake and the morphology of lesions. Lung Rx ^131I-SPECT/CT plays an important role in the disease assessment and postoperative stage for the elevated serum Tg or uncertain localization of pulmonary lesions by Rx ^131I-WBS in thyroid carcinoma postoperative patients.