Whole-body diffusion-weighted MR and FDG-PET/CT in Hodgkin Lymphoma: Predictive role before treatment and early assessment after two courses of ABVD

Abstract

Purpose: To evaluate whether imaging features of pathologic lymph nodes on whole-body diffusion-weighted MR have a predictive role before treatment and may assess the response after two courses of chemotherapy in comparison to FDG-PET/CT in Hodgkin Lymphoma.

Materials and methods: We reviewed the whole-body MR and FDG-PET/CT performed on 41 patients with Hodgkin Lymphoma before and after two Doxorubicin-Bleomycin-Vinblastine-Dacarbazine (ABVD). Responder and non-responder lesions were identified on interim-FDG-PET/CT performed after two ABVD. We used Multivariate Generalized Estimating Equations model to assess statistical association between being-responder and baseline-Maximum Standard Uptake Value (SUV_max), baseline and interim-Apparent Diffusion Coefficient (ADC) and size, ADC and size changes during chemotherapy, site of disease, bulky, and stage.

Results: 10/41 (24%) patients were positive on interim-FDG-PET/CT. The interim-FDG-PET/CT positivity was associated with worse cumulative survival rate at 24 months in comparison to interim-FDG-PET/CT negativity (P < .05); 3/10 patients with positive interim-FDG-PET/CT and 1/31 with negative interim-FDG-PET/CT experienced disease progression. Baseline-SUV_max was 11.18 ± 5.58 (3.1-28.0) and baseline-ADC was 0.70 ± 0.14 × 10^-3 mm²/s (0.39-0.98). There was a significant difference between responder and non-responder lesions based on interim-ADC (1.83 ± 0.34 × 10^-3 mm²/s vs. 1.01 ± 0.27 × 10^-3 mm²/s;p <.001), interim-size (3.1 cm² vs. 9.4 cm²;p = .009), and bulky (8.2% vs. 66.7%;p = .002). There was no significant difference between responder and non-responder lesions based on baseline-SUV_max (p = .713), baseline-ADC (p = .253), ADC changes (p = .058), size changes (p = .085), site (p = .209), stage (p = .290), baseline-size (p = .064).

Conclusions: Interim-ADC is helpful for identifying non-responder lesions, while size changes are not useful. Baseline-SUV_max and ADC have no predictive role. Bulky is the most useful imaging parameter to predict suboptimal response to chemotherapy.

Keywords: ABVD; Diffusion weighted imaging; Hodgkin Lymphoma; Magnetic resonance imaging; Positron emission tomography; Whole body imaging.