9. Assessment of Intrathoracic Metastatic Lung Cancer using FDG-PET and CT of the Thorax

Abstract

Purpose: The purpose of this study was to assess the accuracy in localizing mediastinal, hilar and intraparenchymal lymphadenopathy in patients with primary lung carcinomas, using FDG-PET and CT of the thorax and to correlate with surgical pathology.

Method: Thirty-five patients with primary lung carcinomas and minimal metastatic lymph node involvement, (either N⊘ or N1 disease) underwent FDG-PET and CT of the thorax prior to surgical intervention. Both FDG-PET and CT of the thorax were blindly read independent of one another.

Results: Histologically, 23 patients had negative lymph nodes (N⊘) and 12 patients had N1 disease. The imaging performance characteristics for FDG-PET and CT of the thorax in N⊘/N1 disease was evaluated and reported in Table 1

Table 1. Imaging performance characteristics

Empty Cell	FDG-PET (%)	CT of the Thorax (%)
sensitivity	58	67
specificity	87	65
accuracy	77	66
positive predictive II value	70	50
negative predictive II value	80	79

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Conclusion: This study demonstrates the higher specificity, accuracy, PPV, and NPV of FDG-PET over CT of the thorax in patients with minimal lymph node disease.