Preliminary assessment of dynamic contrast-enhanced CT implementation in pretreatment FDG-PET/CT for outcome prediction in head and neck tumors

Background: Recently published data show some controversy concerning the impact of [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in predicting head and neck tumors (HNT) outcome. Assessment of tumor blood supply parameters using dynamic contrast-enhanced CT (DCE-CT) may deliver additional information concerning this important question. Purpose: To evaluate the contribution of DCE-CT implemented in pretherapeutic FDG-PET/CT protocol for prognosis prediction in patients with HNT. Material and Methods: Ten consecutive patients (median age 50 years, range 47–74 years) with histologically proven HNT underwent FDG-PET/CT with DCE-CT before treatment. FDG uptake was measured by maximum standardized uptake value (SUVmax). Relative tumor blood volume (rTBV) was determined from DCE-CT using Patlak analysis. Intratumoral heterogeneity was assessed by means of lacunarity analysis. Obtained values were compared with time-to-progression and overall survival. PET and DCE-CT images were compared on a pixel-by-pixel basis using Pearson coefficient of correlation. Results: Three patients with lower FDG uptake (SUVmax: 8±1) and five patients with higher FDG uptake (SUVmax: 15±4, P=0.004) were free of local recurrence for 24 months. Two groups of patients with significantly differing lower (group A: 0.37±0.02, n=6) and higher (group B: 0.52±0.01, n=4; P2=0.1). Conclusion: FDG-PET/CT and DCT-CT are complementary methods for surveillance assessment in patients with HNT. Implementation of DCE-CT in the pretreatment FDG-PET/CT protocol may improve tumor outcome prediction.