Variations in apparent diffusion coefficient values following chemotherapy in pediatric neuroblastoma

Abstract

Purpose: In children the assessment of solid tumors' response to chemotherapy is based primarily on size reduction, which can be unreliable and a late marker, in the presence of necrosis. We aimed to establish whether apparent diffusion coefficient (ADC) values of childhood neuroblastomas show proportional changes in relation to chemotherapy response.

Methods: We evaluated 15 pediatric patients with abdominopelvic neuroblastomas, who had undergone MRI before and after chemotherapy. Two radiologists retrospectively analyzed all images by drawing a round uniform region-of-interest in the solid/contrast-enhancing portion of the lesions in consensus. The ADC values from pre- and postchemotherapy images were compared.

Results: Postchemotherapy ADC values were significantly higher than those obtained before treatment (P < 0.05, for minimum, maximum, and median ADC values).

Conclusion: Our results support diffusion-weighted MRI as a promising noninvasive biomarker of therapeutic responses. To the best of our knowledge, this is the first report to compare diffusion- weighted imaging findings before and after chemotherapy in childhood neuroblastic tumors.

Figure 1. a–c.

Axial T2-weighted (a), precontrast (b), and postcontrast (c) T1-weighted images showing the solid portion of a left-sided paravertebral ganglioneuroblastoma (arrow).

Figure 2. a, b.

An example of a region-of-interest drawn on an ADC map of a ganglioneuroblastoma before (a) and after chemotherapy (b). The mean ADC values were measured as 0.95×10⁻³ mm²/s and 1.42×10⁻³ mm²/s, respectively.