符合线路SPECT／低剂量CT^(18)F-FDG显像在肺肿瘤术前诊断中的应用

^(18)F-FDG imaging by coincidence circuit SPECT with low-dose CT in preoperative assessment of pulmonary lesions

目的评价带有低剂量定位CT系统的SPECT对肺癌诊断和非小细胞性肺癌(NSCLC)纵隔淋巴结转移诊断的临床价值。方法使用GE-Millennium VG with Hawkeye成像仪对高分辨CT不能确诊的48例可疑肺癌患者进行了18F-FDG符合线路显像,将显像结果与术后病理诊断进行比较,评价其对肺部原发肿瘤良、恶性鉴别诊断的价值;同时,对24例NSCLC患者术中摘取的74个淋巴结在相应淋巴结区内进行18F-FDG符合线路显像与病理诊断之间的病灶与病灶对比,评价其对淋巴结转移诊断的临床价值。结果18F-FDG符合线路显像显示,有40例患者出现了肺部异常FDG摄取情况。根据形态及核素摄取特征,18F-FDG符合线路显像正确检出恶性病变34例,排除恶性病变6例,出现假阳性6例和假阴性2例,对原发肺癌诊断的灵敏度、特异性和准确性分别为94．4％、50．0％和83．3％;同时,在4例患者中检出了CT未发现的、发生于肾上腺和骨的肺外转移。恶性肿瘤对FDG的摄取明显高于良性肿瘤,且鳞癌高于腺癌。在NSCLC纵隔淋巴结转移的诊断中,淋巴结区与淋巴结区的对比显示,18F-FDG符合线路显像对纵隔淋巴结转移诊断的灵敏度、特异性和准确性分别为57．9%、90．9％和82．4％;而影像诊断与临床诊断之间的比较显示,其诊断的灵敏度、特异性和准确性分别为61．5％、81．8％和70．8％。结论使用带有低剂量定位CT系统的SPECT行18F-FDG显像,对肺部肿瘤的良、恶性鉴别诊断及肺外转移病灶的检出具有较高的诊断价值,但在对NSCLC患者的临床分期上其应用价值有限。

Objective To assess the clinical diagnostic value of ^18F-FDG imaging by coincidence circuit SPECT with low-dose CT in differential diagnosis of pulmonary lesions and mediastinal lymph node involvement, which can not be definitely diagnosed based on regular CT image in patients with non-small-cell lung cancer （NSCLC）. Methods By using GE-Millennium VG with Hawkeye, IS F-FDG imaging was carried out in 48 patients with suspected lung cancer. Clinical value of ^18F-FDG imaging for diagnosing malignancy was evaluated through comparison with the final pathological results. Mediastinal lymph node involvement was also assessed through lesion-by-lesion comparison with pathologic results in 74 lymph node regions from 24 patients. Results Final pathologic diagnoses of these patients were 36 malignancies consisting of 20 adenocarcinomas, 12 squamous cell carcinomas, 3 small cell carcinomas and 1 large cell carcinoma; 12 benign tumors including 6 pneumonias, 2 tuberculosis, 2 hamatomas, 1 cyst and 1 neurofibroma. Of 48 patients, uptake of ^18F-FDG in the chest was found to be abnormal in 40. Correct diagnosis were made in 34 malignancies and 6 false positive lesions were excluded based on morphology and ^18F-FDG uptake status of the lesion. There were 6 false positive and 2 false negative cases. Furthermore, extrathoracic metastases which were not showed on previous CT image in 4 patients including one in the adrenal gland and 3 in the bone were detected by ^18F-FDG imaging. The sensitivity, specificity and accuracy of the ^18F-FDG imaging for differentiating malignant tumor from benign was 94.4%, 50.0% and 83.3%, respectively. Squamous cell carcinoma was found to uptake more FDG than adenocarcinoma. For determination of mediastinal lymph node involvement, the sensitivity, specificity and accuracy of ^18F-FDG imaging was 57.9%, 90. 9% and 82.4%, respectively through lesion-by-lesion comparison; whereas,which was 61.5%, 81.8% and 70.8%, respectively, based on case-by-case comparison. Conclusion ^18F-FDG imaging by coincidence circuit SPECT with low-dose CT is quite helpful in differential diagnosis for patient with undetermined lesion on regular CT image, but it is limited for staging of lung cancer in the patients with non-small cell lung cancer,