Abstract
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 (ADCmean) and maximum SUV (SUVmax) were recorded and correlation assessed using Spearman statistics.
Results:
Fifty-three ROIs were sampled. Pre- and post-treatment ADCmean ranged from 0.77 × 10-3 to 1.79 × 10-3 (median 1.15 × 10-3 mm2s-1) and 1.08 × 10-3 to 3.18 × 10-3 (median 1.88 × 10-3mm2s-1), and SUVmax 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 ADCmean was higher, and median SUVmax lower than pre-treatment values (p< 0.0001). There was an inverse correlation between pre-treatment ADCmean and SUVmax (p=0.005) and between fractional change ([post-treatment – pre-treatment]/pre-treatment) in ADCmean and SUVmax (p=0.002).
Conclusion:
Our results confirm a strong reciprocal relationship between nodal ADCmean and SUVmax in Hodgkin lymphoma; supporting the potential application of quantitative DWI as a functional biomarker of disease.