Role of PET/CT in Differentiating Bronchogenic Carcinoma from Inseparable Pseudo-Neoplastic Lesions

Abstract

Background: Bronchogenic carcinoma is the single most important cause of cancer-related deaths with approximately 1.5 million cases worldwide every year. Computed tomography (CT) scanning can only estimate the proximal extent “with difficulty in visualization the real borders” of a tumor. The role of MRI in local staging of bronchogenic carcinoma is limited by the signal loss secondary to respiratory motion and heterogeneity of the magnetic field caused by the tissue/air interfaces. Positron Emission tomography combined with CT (PET/CT can accurately delineate the viable tumor from surrounding atelectasis and collapse/consolidation, this information cannot only demarcate the size and extent of the tumor for accurate T staging, but also provide guidance for biopsies if histological confirmation is required Purpose: It was to emphasize the role of PET/CT in differentiation the bronchogenic carcinoma from its inseparable pseudo-neoplastic lesions for better staging and increase the accuracy of follow up by ruling out the pseudo progression as well as pseudo regression. Patients and Methods: The study involved 32 patients proved histo-pathologically to have bronchogenic carcinoma and referred for PET/CT scanning. Each patient included in the study was subjected to full history taking, reviewing medical sheet and PET/CT examination. The study was done in private center (Techno-scan holding center, Heliopolis branch using PET-CT machine (GE Discovery VCT 64 PET/CT, USA); in which PET-CT examination was followed by diagnostic contrast enhanced CT examination and processed at Ain Shams University, Radiology department. Results: In this study we found presence of inseparable pseudo neoplastic lesions among 20 patients out of 32 patients and the mean diameter of the bronchogenic mass lesion was 6.89 +/- 3.65 SD as measured by CT, while it was 5.77 +/-3.38 SD as measured by PET/CT in centimeters. Conclusion: The combined PET/CT using 18F-FDG is the best oncologic imaging modality with valuable role in local staging and follows up in patients of bronchogenic carcinoma.