Role of Diffusion MRI & Dynamic Contrast-enhanced MRI in Assessment of Hepatocellular Carcinoma after Trans-arterial Chemoembolization

Abstract:Purpose: to assess the effectiveness of diffusion & Dynamic contrast enhanced MRI in imaging of hepatocellular carcinoma after chemoembolization.
Patients and Methods: between November 2011 & September 2013, 30 patients were treated with chemoembolization in our interventional radiology unit. All patients underwent pretreatment MRI within 10 days before chemoembolization & post-treatment MRI after one month from treatment. The arterial enhancement as well as the mean Apparent Diffusion Coefficient (ADC) of the focal lesion was prospectively assessed & the percent change in both was assessed. The significance of differences between ADC values of complete & partially responding lesions was calculated.
 Results: Thirty male patients, ranging in age between 51 & 73 years who met the inclusion criteria were prospectively studied. According to the results of this study, there was a statistically significant difference between patients with partial response & those with complete response as regard the percent change in the mean ADC value of the focal lesion after treatment with P-value less than 0.001. There was significant positive correlation between the percent change in the mean ADC value & the percent change in the diameter of the enhancing tumor tissue after treatment. The percent change in the mean ADC value among patients with complete response was higher than that among patients with partial response with P-value less than 0.001. The best predictive cut off value for differentiation between complete & partial response was 24 % increase in the mean ADC value, with 99 % sensitivity, 84 % specificity, 90 % positive predictive value, 99 % negative predictive value & 86 % accuracy. The % change of the mean ADC value is considered better positive than negative predictor for response to treatment. On the otherhand, there was no statistically significant difference between patients with complete & partial response as regard the mean ADC of the focal lesion before chemoembolization.
Conclusion: After chemoembolization, completely responding HCC lesions exhibited more increases in the mean ADC than partially responding lesions. Pretreatment mean ADC values were not predictive of response to chemoembolization