Patterns of shift in ADC distributions in abdominal tumours during chemotherapy-feasibility study.

BACKGROUND

Apparent diffusion coefficient (ADC) relates to tissue cellularity, and change in ADC during chemotherapy may be a promising tool for assessing oncological response.

OBJECTIVE

To investigate the feasibility of measuring changes in ADC distribution in solid abdominal and pelvic paediatric tumours during chemotherapy, and to assess patterns of change.

MATERIALS AND METHODS

Consecutive children were included in a prospective observational study. ADC maps were calculated at presentation and following chemotherapy from a diffusion-sensitised sequence. ADC distribution in the whole tumour, excluding areas of low or absent gadolinium-enhancement, was investigated. Change during chemotherapy was assessed for each patient individually. Histopathological slices from the resected specimens were reviewed.

RESULTS

There were seven children (nine tumours) included in the study. ADC in all except one deviated from a normal distribution. All tumours changed their ADC distribution during chemotherapy. Median ADC increased in all upper abdominal tumours, but more in tumours with histopathologically good or marked response to chemotherapy. Seven out of nine tumours attained a wider ADC distribution, the remaining two showed little chemotherapy response.

CONCLUSION

ADC distribution changes during chemotherapy in childhood abdominal tumours are measurable. Distinct patterns of shift can be observed and ADC change is therefore promising as a noninvasive biomarker for therapy response.