Correlation between apparent diffusion coefficients and metabolic parameters in hypopharyngeal squamous cell carcinoma: A prospective study with integrated PET/MRI.

PURPOSE

Apparent diffusion coefficients (ADCs) derived from diffusion-weighted magnetic resonance imaging (DW-MRI) and metabolic parameters derived from F-FDG positron emission tomography (PET) are promising prognostic indicators for head and neck squamous cell carcinoma (SCC). However, the relationship between them remains unclear. This study aimed to investigate the relationship between ADCs and metabolic parameters in hypopharyngeal SCC (HSCC) using integrated PET/MRI.

MATERIALS AND METHODS

Twenty-seven patients with biopsy-proven HSCC underwent integrated F-FDG neck PET/MRI. ADCs of HSCC, including the mean and minimum ADC values (ADC and ADC), were measured manually on ADC maps. Metabolic parameters of HSCC, including maximum and mean standardized uptake values (SUV and SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), were calculated automatically on PET images. Spearman correlation coefficients were used to assess the relationships between ADCs and metabolic parameters in HSCC tumors as well as in tumor groups with different histological grading, clinical staging, and anatomical subsites. P values < 0.05 were considered statistically significant.

RESULTS

No significant correlation was observed between ADCs and F-FDG PET metabolic parameters in the entire cohort, except for a significant inverse correlation between ADC and MTV (r = -0.556, P = 0.003). Furthermore, a significant inverse correlation was observed between ADC and MTV of HSCC in the moderately to well differentiated group (r = -0.692, P = 0.006), stage III group (r = -0.758, P = 0.003), and pyriform sinus group (r = -0.665, P = 0.007), whereas no significant correlation was observed in the poorly differentiated group, stage IV group, or non-pyriform sinus group.

CONCLUSIONS

Inverse correlation between ADC and MTV in the HSCC population was observed and the correlativity depended on histological grading, clinical staging, and anatomical subsites of HSCC.