细支气管肺泡癌^18F—FDG PET／CT显像的代谢和形态特征

目的分析细支气管肺泡癌（BAC）在^18F-脱氧葡萄糖（FDG）PET／CT图像中的代谢和形态结构特征，并与非细支气管肺泡型腺癌（non—BAC AC）的显像结果进行比较，探讨PET／CT在BAC诊断及鉴别诊断中的价值。方法回顾性分析经病理检查确诊的32例BAC及55例non—BAC AC的FDG PET／CT显像资料。测量病灶最大标准摄取值（SUVmax），分析病灶位置、形态及边界、密度分布及其他典型CT结构征象。统计分析比较2组的平均SUVmax，评价与肿瘤分型有关的CT征象，比较单独PET、CT及PET和CT联合诊断的准确性。采用SPSS12．0软件对数据行t检验、McNemar检验、Fisher精确检验等。结果BAC组共47个病灶，non—BACAC组共63个病灶，组间SUVmax差异有统计学意义（1．51±0．17与6．28±3．04，t=-10．374，P〈0．0001）。BAC组纯磨玻璃密度影（45％的病灶，21／47）是相关的CT征象（Fisher精确检验，P〈0．0001）。结合PET代谢和CT解剖结构特征的联合诊断准确性与单独PET或CT对比，差异均有统计学意义（P=0．001和0．039），诊断准确性分别为88％（28／32）、47％（15／32）和66％（21／32）。结论理解FDG PET／CT显像中BAC的代谢和形态结构特征，有利于提高诊断准确性。如动态观察中呈持续的CT磨玻璃密度影，即使低FDG摄取，也要考虑BAC可能。

Metabolic and anatomic characteristics of bronchioloalveolar carcinoma on 18F-FDG PET/CT

Objective The aims were to investigate the value of 18F-fluorodeoxyglucose (FDG) PET/CT in the diagnosis of bronehioloalveolar carcinoma (BAC) and its metabolic and anatomic features in differentiating from non-BAC adenocareinoma (non-BAC AC ). Methods This was a retrospective 18F-FDG PET/CT study on a consecutive series of 87 patients (32 BAC, 55 non-BAC AC) with 110 pathology-proven lesions. The maximum standardized uptake value ( SUVmax) was calculated for all lesions. Tumor's location, morphology and margins, internal structures were analyzed on CT. Statistical analysis compared the mean SUVmax between the two groups, analysed the relationship between tumor subtype and features on CT and compared the diagnostie aeeuraeies with PET alone, CT alone and PET/CT. The t-test, McNemar test, Fisher exact test were used to analyze the data using SPSS 12.0. Results Significant differences were found between mean SUVmax in a total of 47 lesions with BAC and 63 lesions with non-BAC AC (1.51±0.17 vs 6.28± 3.04, t=-10.374, P <0.0001 ). Pure ground glass density, which was foued in BAC, was the most significant CT feature in distinguishing tumor types ( Fisher exact test, P<0.0001 ). Diagnos-tic accuracies were 88% (28/32) with PET/CT, 47% (15/32) with PET and 66% (21/32) with CT. Differences in aeeuraeies between PET and PET/CT and between CT and PET/CT were statistically signifi-cant (P= 0.001,0.039 ). Conclusions Diagnostie accuracy can be higher by understanding the function-al eharaeteristies on PET and anatomical features on CT. The presence of persistent ground glass in a lesion on CT is a significant feature for BAC and should raise the suspicion of this tumor type even in cases of low 18F-FDG activity.