Aims: The aim of our study was to assess the correlations between apparent diffusion coefficient (ADC) values and standardized uptake values (SUVs) and their correlations with tumor size, tumor stage and histological grade in patients with head and neck squamous cell carcinomas (HNSSCs).
Methods: This retrospective study included 36 patients with histologically confirmed HNSSCs visible on diffusion weighted imaging (DWI) and fluorodeoxyglucose (FDG) positron emission tomography (PET/CT). Correlations of minimum ADC (ADCmin), mean ADC (ADCmean), and minimum-mean ADC ratio (ADCmin/mean) with maximum SUV (SUVmax) and lean body mass SUVlbm (SUVlbm) were analyzed using the Spearman’s correlation test. The Kruskal-Wallis one-way ANOVA test and Mann-Whitney U test were used to assess the correlations of ADC values and SUVs with tumor size, tumor stage and histological grade. Two experienced readers measured the ADC and SUVs independently, and intraclass correlation coefficient (ICC) was used to analyze the inter-observer agreement.
Results: The mean ADCmin, ADCmean, and ADCmin/mean for HNSSCs were 0.68±0.17×10−3 mm2/s, 0.82±0.17×10−3 mm2/s, and 0.83±0.10, respectively. The mean SUVmax and SUVlbm were 14.65±5.5 and 10.96±5.1, respectively. The correlations between ADC values and SUVs did not reach statistical significance. There were no significant correlations of ADC values and SUVs with tumor size, tumor stage or histological grade. There was a tendency of SUVs to increase and ADC values to decrease with tumor dedifferentiation; however, the changes were not significant. Inter-observer agreement for tumor ADC values and SUVs was almost perfect (ICC>0.81).
Conclusions: Pretreatment ADC values and SUVs in HNSSCs are reproducible and independent biomarkers