PET Center, Huashan Hospital, Fudan University, Shanghai, China.
Ann Nucl Med. 2010 Oct;24(8):571-7. doi: 10.1007/s12149-010-0394-6. Epub 2010 Jul 17.
The objective of this study was to evaluate the incidence of incidental parotid masses with conventional whole-body ¹⁸F-deoxyglucose (FDG) PET/CT and assess the ability of PET/CT to characterize these unexpected parotid lesions.
Fifty eight incidental findings of parotid masses with routine FDG PET/CT whole-body scan were reviewed in this retrospective analysis, which were selected from the patients without any known or suspected parotid disease in our PET center, from June 2005 to May 2009. 51 cases were operated or underwent a biopsy after a short-term PET/CT study; the remaining 7 cases had a follow-up. Parotid mass that showed both noncontrast CT (irregular shape and blurry border) and PET malignant features (high FDG uptake, SUV(max) > 3.0) was considered as positive for malignancy. Correlation of FDG PET/CT with histology or follow-up outcome was performed.
Fifty eight unexpected findings of parotid masses accounted for 0.3% of the total cases in 4 years, including 11 (19.0%) malignant tumors and 47 (81.0%) benign lesions. 13 lesions manifested single nodule with malignant CT features and intense FDG activity, of which 6 were proved to be malignant; thus, sensitivity and positive predictive values were 54.5% (6 of 11) and 46.2% (6 of 13), respectively. 45 lesions showed either single nodule with benign CT features, or a low FDG uptake (SUV(max) ≤ 3.0), of which 40 were true negatives; therefore, specificity and negative predictive values were 85.1% (40 of 47) and 88.9% (40 of 45), respectively. All parotid masses except 9 benign and 1 malignant showed a high FDG uptake. Compared with SUV only, combined interpretation of PET and CT results displayed a lower sensitivity (90.9-54.5%), but a higher specificity (19.1-85.1%) and a higher overall accuracy.
Whole-body FDG-PET/CT at the time of surveying the entire body condition is helpful for detecting the asymptomatic parotid masses. Combined noncontrast CT is an essential evidence for improving the diagnostic accuracy of FDG-PET/CT for parotid masses.
本研究旨在评估常规全身¹⁸F-脱氧葡萄糖（FDG）PET/CT 检查中偶然发现的腮腺肿块的发生率，并评估 PET/CT 对这些意外腮腺病变的特征描述能力。
回顾性分析 2005 年 6 月至 2009 年 5 月期间，在我院 PET 中心，于常规 FDG PET/CT 全身扫描中偶然发现的 58 例腮腺肿块患者。51 例患者在短期 PET/CT 研究后接受了手术或活检；其余 7 例患者进行了随访。如果腮腺肿块的 CT 平扫表现为形态不规则、边界模糊（即非对比 CT 特征），且 PET 检查显示为高 FDG 摄取（SUV(max) > 3.0），则被认为具有恶性特征。将 FDG PET/CT 与组织学或随访结果进行相关性分析。
4 年内，58 例偶然发现的腮腺肿块占总病例的 0.3%，其中 11 例（19.0%）为恶性肿瘤，47 例（81.0%）为良性病变。13 例肿块表现为具有恶性 CT 特征和强烈 FDG 活性的单个结节，其中 6 例证实为恶性，因此，灵敏度和阳性预测值分别为 54.5%（6 例/11 例）和 46.2%（6 例/13 例）。45 例肿块表现为形态规则、边界清晰的单个结节或 FDG 摄取较低（SUV(max) ≤ 3.0），其中 40 例为真阴性，因此，特异性和阴性预测值分别为 85.1%（40 例/47 例）和 88.9%（40 例/45 例）。除了 9 例良性和 1 例恶性肿瘤外，所有腮腺肿块均表现为高 FDG 摄取。与仅使用 SUV 相比，联合解读 PET 和 CT 结果的灵敏度（90.9%54.5%）降低，但特异性（19.1%85.1%）和总体准确性提高。
在评估全身状况时进行全身¹⁸F-FDG-PET/CT 有助于检测无症状的腮腺肿块。非对比 CT 是提高 FDG-PET/CT 对腮腺肿块诊断准确性的重要依据。
