Diagnosis of the presence of lymph node metastasis and decision of operative indication using fluorodeoxyglucose-positron emission tomography and computed tomography in patients with primary lung cancer

Abstract

: Objectives : We evaluate whether integrated fluorodeoxyglucose-positron emission tomography and computed tomography (FDG-PET/CT) scan can diagnose the presence of lymph node metastasis more accurately than computed tomography (CT) scan alone. Methods : Forty-two patients with lung cancer preoperatively underwent integrated PET/CT scan using FDG and CT scan and underwent pulmonary resection and lymph node dissection. We judged cases as lymph node metastasis if the lymph node visually accumulated FDG at PET/CT scan and measured 1 cm or greater in the short axis at CT scan. We retrospectively analyzed whether our judgments in each modality were consistent with the pathological diagnosis. Results : Two-hundred and seventeen stations of lymph node were dissected and 21 stations (9.7% %) were histologically diagnosed as positive metastasis. Thirty-two stations of lymph node visually accumulated FDG at PET/CT scan and 17 stations measured 1 cm or greater in the short axis at CT scan. Concerning the diagnosis of lymph node metastasis, PET/CT scan showed significantly higher sensitivity than CT scan (81% % vs. 48% %, p=0.024). The false-positive rate was significantly high in PET-positive lymph nodes measuring less than 1 cm in diameter. There were 4 falsenegative lymph nodes with both scans. All of these were less than 7 mm in diameter and had a low percentage of metastatic foci in the lymph node. Concerning the diagnosis of N staging, there was no significant difference between PET/CT scan and CT scan (83% vs. 69% %, p=0.124). However, the identification of N2 disease at PET/CT scan was significantly more accurate than that at CT scan (100% % vs. 38% %, p=0.031). Conclusions : PET/CT is superior to CT scan in lymph node staging. However, because the false-positive rate is high in PET-positive lymph nodes measuring less than 1 cm in diameter, we think that clinical background should be considered and other modalities or histological examinations should be undertaken if necessary. J. Med. Invest. 57 : 305-313, August, 2010

Diagnostic value of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography for the detection of metastases in non–small‐cell lung cancer patients

“…1). The characteristics of the 56 studies was shown in Supporting Information Table 1 4–6, 14, 23–74. Among the included studies, 46 evaluated LN metastatic disease and 13 assessed extrathoracic metastatic disease.…”

Dual-Energy CT in the Assessment of Mediastinal Lymph Nodes: Comparative Study of Virtual Non-Contrast and True Non-Contrast Images

“…Lymph nodes showing false positive FDG uptake have histopathologic characteristics that include anthracofibrosis, lymphoid follicular hyperplasia, and granulomatous infection, and may demonstrate calcification or CT attenuation greater than that caused by the great vessels on non-contrast CT images (1, 4-6). Li et al (2) reported that nodes showing CT attenuation higher than that of the aorta were determined to be benign despite showing positive FDG uptake.…”

“…First, the number of nodes showing visual scores of 1 or 2 was small (16/112 in TNC images), which may be because the study included only those nodes that were > 1 cm in short diameter. Most nodes that show false positive FDG uptake and high CT attenuation are small, usually < 1 cm in size (4). We did not include such small nodes because the measurement of CT attenuation may then be more strongly influenced by partial volume artifacts.…”

Role of FDG-PET scans in staging, response assessment, and follow-up care for non-small cell lung cancer

“…Toba et al (2010) showed the positive predictive value (PPV) of FDG-PET to be significantly lower with lesions <1 cm in size compared with larger lesions (0.36 vs 0.90, p = 0.015). The lower PPV of smaller lesions reflects a higher rate of falsely positive FDG-PET scans.…”