56P - FDG PET/CT for evaluation of mediastinal lymph node staging using FDG uptake and volumetric CT histogram in non-small cell lung cancer

Date 17 April 2015
Event ELCC 2015
Session Poster lunch
Topics Imaging, Diagnosis and Staging
Lung and other Thoracic Tumours
Presenter Jeong Won Lee
Citation Annals of Oncology (2015) 26 (suppl_1): 15-16. 10.1093/annonc/mdv046
Authors S.M. Lee1, J.W. Lee2, J. Lee3
  • 1Department Of Nuclear Medicine, Soonchunhyang University Hospital, 330-721 - Cheonan/KR
  • 2Department Of Nuclear Medicine, Catholic Kwandong University International St. Mary’s Hospital, 404-834 - Incheon/KR
  • 3Department Of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 135-720 - Seoul/KR

Abstract

Aim/Background

The purpose of thise study was to evaluate the clinical implications of lymph node density based on CT histogram analysis on 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for mediastinal lymph node characterization in non-small cell lung cancer (NSCLC) patients.

Methods

In all, 152 NSCLC patients with 271 mediastinal lymph nodes who underwent FDG PET/CT and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for staging were enrolled. The maximum standardized uptake value (SUVmax), size, the primary cancer-to-lymph node ratio of SUVmax (PLR), and median HU based on CT histogram of the lymph nodes were measured and correlated to the histopathological results.

Results

Of enrolled 271 lymph nodes, 162 (59.8%) were malignant. SUVmax, size, and PLR of the malignant lymph nodes were significantly higher than those of the benign nodes (p < 0.05). The median HUs of malignant nodes were mainly distributed around 25-45 HU, while the most (78.9%) of the benign lymph nodes had lower or higher HU than 25-45 HU. Using the cut-off SUVmax of 4.0, SUVmax showed the highest diagnostic ability for detecting malignant lymph nodes among SUVmax, size and PLR with the specificity 94.5%, however, only showed the moderate sensitivity of 70.4%. Among the lymph nodes with SUVmax ≤ 4.0, 58.2% of lymph nodes between 25-45 HU were malignant; meanwhile, 83.3% of lymph nodes with < 25 HU or > 45 HU were benign.

Conclusions

The lymph node density based on CT histogram analysis provides useful information for the characterization of the lymph nodes with mild FDG uptake. With using both FDG uptake and lymph node density, we could stratify the risk of malignant involvement of the mediastinal lymph nodes in NSCLC patients.

Disclosure

All authors have declared no conflicts of interest.