Dynamic MRI signals in the second week of radiotherapy relate to treatment outcomes of hepatocellular carcinoma: a preliminary result.

Aim: Radiotherapy (RT) has been used to treat hepatocellular carcinoma (HCC) in recent years. Despite its good local control, slow tumoral shrinkage and rapid recurrence compromise treatment outcomes. We evaluated the signal intensity of the hepatic parenchyma and tumours by using dynamic contrast enhanced magnetic resonance imaging (MRI) and correlated the findings with clinical outcomes. Nineteen patients with advanced HCC received 50 Gy in 25 fractions. They underwent a dynamic contrast-enhanced, turbo fast low-angle shot MR sequence at 1.5 T before therapy, at 2 weeks of therapy, and 1 month (week 9) later. Initial first-pass enhancement slopes (slope) and peak enhancement ratios (peak) were measured.

Results: Initial signal intensities were not associated with RT outcomes. An increased slope and peak of the tumour at week 2 was associated with an improved local response (P<0.05). In the parenchyma, an increased slope at week 2 was associated with recurrence outside the radiation fields or with progression over distant sites (P<0.05). The differences in signal changes at week 2 during RT were not persistent at a statistically significant level at 1 month after RT.

Conclusion: Dynamic contrast-enhanced MRI signals may act as biomarkers for early prediction of responses to RT in patients with HCC. Signal intensities at week 2 are important in evaluating treatment outcomes.