Correlation of apparent diffusion coefficients measured by 3T diffusion-weighted MRI and SUV from FDG PET/CT in primary cervical cancer

Purpose Diffusion-weighted magnetic resonance imaging (DWI) and fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) are oncological feasible techniques. Currently, apparent diffusion coefficient (ADC) measured by DWI and standard uptake value (SUV) from FDG PET/CT have similar applications in clinical oncology. The aim of this study was to assess the correlation between ADC and SUV in primary cervical cancer. Materials and methods Patients with documented primary cervical cancer were recruited. All participants underwent abdominopelvic DWI at 3T and FDG PET/CT within 2 weeks. For the primary tumor, ADC was measured as minimum ADC (ADC(min)) and mean ADC (ADC(mean)) within the whole tumor by DWI. Maximum SUV (SUVmax) and mean SUV (SUVmean) were measured by FDG PET/CT. Results A total of 33 patients were included. There was no significant correlation either between ADC(min) and SUVmax or between ADC(mean) and SUVmean. The relative ADC(min) (rADC(min)) defined as ADC(min)/ADC(mean) ratio was significantly inversely correlated with the relative SUVmax (rSUV(max)) defined as SUVmax/SUVmean ratio (r=-0.526, P=0.0017) in all study patients. A significantly inverse correlation between rADC(min) and rSUV(max) was observed in patients with adenocarcinoma/adenosquamous carcinoma (r=-0.685, P=0.0012) and those with well-to-moderate differentiated tumor (r=-0.631, P=0.0050). No significant correlation was demonstrated in patients with squamous cell carcinoma or poorly differentiated tumor. Conclusions The significantly inverse correlation between rADC(min) and rSUV(max) in primary cervical tumor suggests that DWI and FDG PET/CT might play a complementary role for the clinical assessment of this cancer type.