Figure 1

Early ADC change before HCC lesion reduction obtained at baseline and at different times post-SABR. A 71-year-old man with hepatitis B virus-related liver cirrhosis and a 2.8 cm HCC in segment 7. At baseline MRI, the lesion shows strong enhancement in the arterial phase (A-phase) and washout in the portal venous phase (PV-phase), with moderate hyperintensity on DWI (b = 500) and an ADC of 1.37 × 10−3 mm2/s. At the 2-month follow-up, the lesion was stable in size by mRECIST. Lower hyperintensity at DWI was noted with a corresponding ADC of 2.00 × 10−3 mm2/s (a 46% increase). Geographic parenchymal hyperenhancement was noted in both the A- and PV-phases, consistent with focal liver reaction to SABR. At the 5-month follow-up, the lesion had a lower enhancement size (1.9 cm), indicative of partial response, with resolution of geographic parenchyma hyperenhancement. At the 8-month follow-up, no enhancement was observed, indicating complete response. Continuous volume loss of the overlying liver parenchyma was observed at 5 and 8 months.