Bar-Shalom Rachel, Kagna Olga, Israel Ora, Guralnik Ludmila
Department of Nuclear Medicine, Rambam Health Care Campus, Haifa, Israel.
Cancer. 2008 Dec 1;113(11):3213-21. doi: 10.1002/cncr.23928.
2-Fluoro-2-deoxy-D-glucose (FDG) imaging is highly accurate for assessing solitary pulmonary nodules (SPNs) in patients without known malignancy. In the current study, the authors evaluated FDG-positron emission tomography/computed tomography (PET/CT) for the characterization of SPN in cancer patients.
FDG-PET/CT was performed in 56 cancer patients to evaluate SPNs that measured 15 +/- 8 mm in greatest dimension. The diagnosis was confirmed by histology (n = 34 patients), or by CT or clinical follow-up (n = 22 patients). The performance of PET/CT was calculated for visual and semiquantitative assessment and was related to SPN size, location, histology, and time after initial cancer diagnosis.
Malignancy was diagnosed in 27 of 56 SPNs (48%; 18 second primary tumors and 9 metastases). There were 26 true-positive PET/CT studies (17 second primaries and 9 metastases), 5 false-positive studies, 24 true-negative studies, and 1 false-negative study. The sensitivity of PET/CT for diagnosing malignant SPN in patients with cancer was significantly greater for visual analysis than for semiquantitative analysis (96% vs 89%, respectively; P < .05). Specificity and accuracy were similar for both methods (83% and 89% vs 93% and 91%, respectively). The presence of low-intensity FDG uptake increased the detection rate of malignancy from 4% in non-FDG-avid SPNs to 40%, mainly in second primary tumors. False-positive results were more frequent with lower than mediastinal uptake versus higher than mediastinal uptake (3 of 5 SPNs vs 2 of 26 SPNs, respectively; P < .01) and in SPNs >10 mm.
FDG imaging was highly accurate for the diagnosis of malignant SPNs in patients with cancer, similar to the general population. The presence of any FDG avidity had significantly greater sensitivity than semiquantitative analysis. The current results indicated that lower than mediastinal uptake should be explored cautiously, particularly for second primary tumors, whereas no FDG avidity was a better predictor of SPN benignity than very low uptake.
2-氟-2-脱氧-D-葡萄糖（FDG）成像在评估无已知恶性肿瘤患者的孤立性肺结节（SPN）方面具有高度准确性。在本研究中，作者评估了FDG正电子发射断层扫描/计算机断层扫描（PET/CT）在癌症患者中对SPN的特征描述。
对56例癌症患者进行FDG-PET/CT检查，以评估最大直径为15±8mm的SPN。诊断通过组织学确诊（n = 34例患者），或通过CT或临床随访确诊（n = 22例患者）。计算PET/CT在视觉和半定量评估方面的表现，并与SPN大小、位置、组织学以及初次癌症诊断后的时间相关。
56个SPN中有27个被诊断为恶性（48%；18个第二原发性肿瘤和9个转移瘤）。PET/CT检查有26个真阳性结果（17个第二原发性肿瘤和9个转移瘤），5个假阳性结果，24个真阴性结果，1个假阴性结果。PET/CT在癌症患者中诊断恶性SPN的视觉分析敏感性显著高于半定量分析（分别为96%和89%；P < 0.05）。两种方法的特异性和准确性相似（分别为83%和89%对93%和91%）。FDG摄取强度低使恶性肿瘤的检出率从非FDG摄取阳性的SPN中的4%提高到40%，主要在第二原发性肿瘤中。与高于纵隔摄取相比，低于纵隔摄取的假阳性结果更常见（分别为5个SPN中的3个对26个SPN中的2个；P < 0.01），且在直径>10mm的SPN中更常见。
与普通人群相似，FDG成像在癌症患者中诊断恶性SPN具有高度准确性。任何FDG摄取阳性的敏感性显著高于半定量分析。目前的结果表明，对于低于纵隔摄取应谨慎评估，尤其是对于第二原发性肿瘤，而无FDG摄取阳性比极低摄取更能预测SPN的良性。
