Serial diffusion-weighted MRI in patients with hepatocellular carcinoma: Prediction and assessment of response to transarterial chemoembolization. Preliminary experience

ObjectiveTo assess the role of apparent diffusion coefficient (ADC) measured with diffusion-weighted imaging (DWI) in predicting and assessing response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE).MethodsThirty-six patients with cirrhosis and untreated HCC who underwent TACE and MRI within 3 months before and after TACE were assessed. MRI included DWI and contrast-enhanced T1-weighted imaging. Two observers measured ADC of HCCs and liver parenchyma on pre- and post-TACE MRIs and measured degree of tumor necrosis on subtracted post-contrast images on post-TACE MRI. Pre-, post-TACE tumor ADC, and changes in tumor ADC (ΔADC) were compared between lesions stratified by degree of tumor necrosis (measured on post-TACE MRI).ResultsForty seven HCCs were evaluated (mean size 4.4 cm, range 1.0–14.1 cm). HCCs with poor and incomplete response to TACE (<50% necrosis on post-TACE MRI) had significantly lower pre-treatment ADC and lower post TACE ADC compared to HCCs with good/complete response (≥50% necrosis): ADC pre-TACE 1.35 ± 0.42 vs. 1.64 ± 0.39 × 10−3 mm2/s (p = 0.042); post-TACE ADC 1.34 ± 0.36 vs. 1.92 ± 0.47 (p = 0.0008). There was no difference in ΔADC values.ConclusionThis preliminary data suggests that pre-TACE tumor ADC can be used to predict HCC response to TACE.