Non-small cell lung carcinoma: accuracy of PET/CT in determining the size of T1 and T2 primary tumors.

Abstract

The purpose of this study was to compare the measurements of primary T1 and T2 non-small cell lung carcinomas (NSCLCs) at PET/CT to determine which modality has the more accurate correlation with the histologic findings. A retrospective study was performed with the images of 59 patients who underwent surgical resection of T1 and T2 NSCLC and preoperative PET/CT. The maximum measurement of the primary lung tumor was recorded on the PET and unenhanced CT (soft-tissue and lung windows) scans in the largest plane and compared with the maximum dimensions of the histologic specimen. PET and CT measurements both had high concordance with the histologic measurements. CT soft-tissue window measurements had the highest concordance with histologic measurements, but PET had a smaller SD. The greatest linear correlation was between CT soft-tissue and CT lung window measurements, indicating they can be used interchangeably. Outliers were found in both the PET (four tumors) and the two CT (five tumors) groups owing to low (18)F-FDG uptake due to tumor type and surrounding consolidation, respectively. PET is better for delineating primary NSCLC if surrounding collapse or consolidation is present. Otherwise, CT with either soft-tissue or lung windows is accurate. Owing to low FDG accumulation, CT is more accurate for assessment of alveolar cell carcinoma.