The diagnostic ability of 18F-FDG PET/CT for mediastinal lymph node staging using 18F-FDG uptake and volumetric CT histogram analysis in non-small cell lung cancer

To evaluate the clinical implications of lymph node (LN) density on F-18-FDG PET/CT for mediastinal LN characterization in non-small cell lung cancer (NSCLC). One hundred and fifty-two patients with 271 mediastinal LNs who underwent PET/CT and endobronchial ultrasound-guided transbronchial needle aspiration for staging were enrolled. Maximum standardized uptake value (SUVmax), short axis diameter, LN-to-primary cancer ratio of SUVmax, and median Hounsfield unit (HU) based on CT histogram were correlated to histopathology. Of 271 nodes, 162 (59.8 %) were malignant. SUVmax, short axis diameter, and LPR of malignant LNs were higher than those of benign nodes. Among malignant LNs, 71.0 % had median HU between 25 and 45, while 78.9 % of benign LNs had values < 25 HU or > 45 HU. Using a cutoff value of 4.0, SUVmax showed the highest diagnostic ability for detecting malignant LNs with a specificity of 94.5 %, but showing a sensitivity of 70.4 %. Using additional density criteria (median HU 25-45) in LNs with 2.0 < SUVmax aecurrency sign4.0, the sensitivity increased to 88.3 % with the specificity of 82.6 %. LN density is useful for the characterization of LNs with mild F-18-FDG uptake. The risk of mediastinal LN metastasis in NSCLC patients could be further stratified using both F-18-FDG uptake and LN density. aEuro cent SUVmax showed the highest diagnostic ability for detecting malignant LNs. aEuro cent LN density was useful in characterization of LNs with mild FDG uptake. aEuro cent SUVmax and LN density together could stratify the risk of LN metastasis.