^(18)F-FDG PET/CT显像对孤立结节型细支气管肺泡癌的诊断价值

Diagnostic value of ^(18)F-FDG PET/CT for solitary nodular-type bronchoalveolar carcinoma

目的探讨18F-FDG PET/CT显像诊断孤立结节型细支气管肺泡癌的价值。方法采用回顾性分析,研究对象为2005年8月-2009年12月在广州军区广州总医院行18F-FDG PET/CT显像并经手术病理确诊为细支气管肺泡癌的患者30例。分别记录其形态学表现及放射性分布,同时测量其最大SUV值(SUVmax),并分析PET、PET/CT和HRCT三者的确诊率。结果 PET显示30例细支气管肺泡癌病例中有19例SUVmax≥2.5,呈阳性改变,占63%。5例表现为磨玻璃样改变,另外还有3例为混合性结节(实变结节周围伴有磨玻璃影),22例为实变结节。HRCT显示这类病灶多位于双肺上叶,大多位于肺野外围胸膜下,病灶呈小斑片状或结节状,形态不规则,有分叶征22例,毛刺征15例,胸膜凹陷征21例,空泡征4例。PET、PET/CT和HRCT三者的确诊率分别为36.67%、93.33%和93.33%。结论细支气管肺泡癌的SUVmax值对判断病变的良恶性价值有限,对病变活性程度可作一般性参考。在诊断时应充分发挥PET/CT影像与功能融合的作用,多从影像学角度进行判断(特别是HRCT的BAC征象),以减少误诊率。

Objective To assess the value of 18F-FDG PET/CT in the diagnosis of solitary nodular-type bronchoalveolar carcinoma （BAC）. Methods The clinical and radiographic data were analyzed retrospectively in 30 patients with pathologically confirmed solitary nodular-type BAC who underwent 18F-FDG PET/CT examinations between August, 2005 and December, 2006. The morphological and radioactive findings of the lesions were reviewed, and the maximum standard uptake values （SUVmax） were measured. The diagnostic accuracy of PET, PET/CT, and HRCT were analyzed. Results The 18F-FDG SUV was markedly lower in BAC than in other well differentiated adenocarcinoma. In 19 of the BAC cases, PET showed a SUVmax of no less than 2.5, demonstrating positive changes. Of the total of 30 cases, 5 had ground glass opacity （GGO） changes, 3 exhibited mixed nodules with GGO changes around the lesions, and 22 cases presented with solid nodules. HRCT showed that BAC located often in the superior lobes of the bilateral lungs, mostly below the pleura in the surrounding lung field; the lesions were patchy or nodular with irregular shapes, showing lobulation in 22 cases, spiculation in 15 cases, pleural indentation in 21 cases, and vacuolar changes in 4 cases. The diagnostic accuracy of PET, PET/CT and HRCT for solitary nodular-type BAC was 36.67%, 93.33%, and 93.33%, respectively. Conclusion The SUVmax of BAC provides only limited value for defining the nature of the lesions, but can serve as a general reference for assessing the disease activity. PET/CT, which allows both functional and imaging assessment, can be a valuable modality to reduce the misdiagnosis rate of BAC.