Quantitative diffusion weighted MRI: A functional biomarker of nodal disease in Hodgkin lymphoma?

摘要

Purpose: This study explores the relationship between MRI Apparent Diffusion Coefficient (ADC) and PET Standardized Uptake Value (SUV) measurements in pediatric Hodgkin lymphoma. Methods: Sixteen patients (mean age 15.4 yrs, 8 male) with proven Hodgkin lymphoma were recruited and staged using PET-CT, anatomical MRI and additional 1.5T diffusion weighted imaging (DWI) prior to and following chemotherapy. Pre-treatment lymph nodes and anatomically paired post-treatment residual tissue located on MRI were matched to the corresponding PET-CT. Region of interest (ROI) analysis was used to extract quantitative measurements. Mean ADC (ADC_{mean}) and maximum SUV (SUV_{max}) were recorded and correlation assessed using Spearman statistics. Results: Fifty-three ROIs were sampled. Pre- and post-treatment ADC_{mean} ranged from 0.77 × 10^{-3} to 1.79 × 10^{-3} (median 1.15 × 10^{-3} mm^{2}s^{-1}) and 1.08 × 10^{-3} to 3.18 × 10^{-3} (median 1.88 × 10^{-3}mm^{2}s^{-1}), and SUV_{max} from 2.60 to 25.4 (median 8.85 mg/ml) and 1.00 to 3.50 mg/ml (median 1.90 mg/ml). Median post-treatment ADC_{mean} was higher, and median SUV_{max} lower than pre-treatment values (p< 0.0001). There was an inverse correlation between pre-treatment ADC_{mean} and SUV_{max} (p=0.005) and between fractional change ([post-treatment – pre-treatment]/pre-treatment) in ADC_{mean} and SUV_{max} (p=0.002). Conclusion: Our results confirm a strong~reciprocal relationship between nodal ADC_{mean} and SUV_{max} in Hodgkin lymphoma; supporting the potential application of quantitative DWI as a functional biomarker of disease.