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PET/CT Aids Lung Adenocarcinoma Diagnoses

According to an article published ahead of print in the February 2020 issue of the American Journal of Roentgenology, FDG PET can be used to predict the histopathologic subtypes and growth patterns of early lung adenocarcinoma.

“FDG PET, combined with high-resolution CT [HRCT], has value for predicting invasive histopathologic subtypes, but there was no significance for predicting invasive growth patterns,” says lead author Xiaoliang Shao, MD, from the department of nuclear medicine at Soochow University in Changzhou, China.

Shao and colleagues’ retrospective analysis was conducted on the PET/CT data on ground-glass nodules (GGNs) resected from patients with stage IA lung adenocarcinoma, evaluating the efficacy of PET maximum standardized uptake value (SUVmax) combined with HRCT signs in prediction of histopathologic subtype and growth pattern of lung adenocarcinoma.

Although SUVmax measured significantly higher in GGNs with invasive HRCT signs, the diameter of GGN, as well as the attenuation value differential between ground-glass components and adjacent lung tissues, were independent predictors of FDG uptake by GGNs.

Additionally, SUVmax was higher in invasive adenocarcinoma than in adenocarcinoma in situ–minimally invasive adenocarcinoma, with SUVmax 2.0 the optimal cutoff value for differentiation.

Acinar-papillary adenocarcinoma had a higher SUVmax than lepidic adenocarcinoma, with SUVmax 1.4 the optimal cutoff value for differentiation.

“In stage IA lung adenocarcinoma characterized by GGNs, the SUVmax of GGNs with invasive CT features was high,” according to Shao, who adds that HRCT can be used in diagnosing the subtypes of lung adenocarcinoma.

“However, it cannot be used to differentiate different growth patterns of lung adenocarcinomas.”

Furthermore, “The efficacy of FDG PET SUVmax in differentiating lung adenocarcinoma subtypes is similar to that of HRCT signs, however, the diagnostic efficiency of FDG PET combined with HRCT is significantly higher than that of each imaging technique alone,” Shao says.