Dual-phase Fluorodeoxyglucose Positron Emission Tomography / Computed Tomography for Differentiation of Tuberculoma from Malignancy in Patients Presenting with Solitary Pulmonary Nodules: Local Experience in a Single Centre

Full Article

BT Kung, MO Kong, CP Wong, KS Chu, TK AuYong, CM Tong

Hong Kong J Radiol 2012;15:220-6

Objective: To evaluate whether dual-phase fluorodeoxyglucose (FDG) positron emission tomography / computed tomography (PET/CT) can differentiate tuberculoma from malignancy in patients presenting with solitary pulmonary nodules.

Methods:This was a retrospective study of patients referred to our centre for evaluation of a solitary pulmonary nodule from December 2003 to September 2008. FDG PET/CT studies were performed using a hybrid PET/ CT scanner. Imaging was taken 1 hour and 3.5 hours after injection of the tracer. The maximum standardised uptake value (SUVmax) of the lung lesion in 1 hour and 3.5 hours imaging was designated as SUVe and SUVd, respectively. The difference between them (SUVd – SUVe) was designated as ΔSUV. Results were correlated with the final (histological or clinical) diagnoses. Patients with primary lung cancer and tuberculosis were selected for the analysis.

Results:A total of 26 patients (15 males, 11 females) were investigated during the study period. Among them, 21 (10 males, 11 females) had primary bronchogenic carcinoma and 5 had a tuberculoma (all males). They were followed up for a mean duration of 37 months (range, 6 to 63 months). The malignant nodules had a mean SUVe of 5.2 (range, 0.7 to 15.7) and mean SUVd of 6.5 (range, 0.7 to 19.7), respectively. Tuberculomas had a mean SUVe of 5.1 (range, 1.4 to 9.1) and mean SUVd of 5.6 (range, 1.0 to 8.9), respectively. No statistical significance was found between the two patient groups in terms of SUVe (p = 0.871, Mann-Whitney U test). The mean ΔSUV of malignant solitary pulmonary nodules was 1.3 (range, -1.2 to 7.7) while that of tuberculomas was 0.5 (range, -1.8 to 2.3). Thus, there was no statistically significant difference between the two groups in terms of ΔSUV (p = 0.72, Mann-Whitney U test).

Conclusions: Tuberculomas behave similarly to solitary malignant pulmonary nodules. Dual-phase FDG PET/ CT cannot accurately differentiate between them.



雙相氟化脫氧葡萄糖正電子發射/計算機斷層顯像分辨孤立性肺結節患者 中的肺癌和結核瘤:本地單中心經驗分享


目的:探討雙相氟化脫氧葡萄糖正電子發射/計算機斷層顯像(FDG PET/CT)是否能分辨孤立性肺 結節患者中的肺癌和結核瘤。

方法:本回顧性研究包括有2003年12月至2008年9月因患有孤立性肺結節而轉介至本中心的病人。利 用PET/CT聯合掃描機作出FDG PET/CT檢查。病人注射示踪劑1及3.5小時後作影像檢查,而肺部病變 的最大標準化攝取值(SUVmax)分別設定為SUVe(1小時後)和SUVd(3.5小時後)。兩者的差值 (即SUVd–SUVe)為ΔSUV。結果與最終診斷(即組織學或臨床)作相關性分析。患有原發性肺癌 及肺結核的病人結果將用作分析用途。

結果:研究期間共有26名病人,包括15男11女,其中21人(10男11女)患有原發性支氣管癌,另5 名男病人患有結核瘤。病人的隨訪期平均為37個月(介乎6至63個月)。惡性結節的SUVe平均值為 5.2(介乎0.7至15.7)、SUVd平均值為6.5(介乎0.7至19.7)。結核瘤的SUVe平均值為5.1(介乎1.4 至9.1)、SUVd平均值為5.6(介乎1.0至8.9)。比較兩組病人的SUVe值並無統計顯著性(p = 0.871, 曼—惠特尼U檢定)。惡性孤立性肺結節的ΔSUV平均值為1.3(介乎-1.2至7.7),而結核瘤的相應值 為0.5(介乎-1.8至2.3)。因此,兩個組別的ΔSUV值並無顯著統計學差異(p = 0.72,曼—惠特尼U檢 定)。

結論:結核瘤的表現與惡性孤立性肺結節類似,所以雙相FDG PET/CT檢查並不能分辨兩種病患。