Dynamic Subtraction MRI Versus Diffusion Weighted Imaging in Assessment of Hepatocellular Carcinoma after Trans Arterial Chemoembolization (TACE)

Abstract Background: Hepatocellular carcinoma (HCC) was found to be the 4th leading cause of cancer-related deaths. Guided by the Barcelona Clinic Liver Cancer (BCLC) classification system, trans-arterial chemoembolization (TACE) is the first line of treatment for HCC patients with intermediate stage and possibly those with sizable or multi-centric HCC. Aim of Study: The current study aim was to compare subtraction dynamic contrast enhanced MRI to diffusion weighted imaging in assessment of HCC cases following TACE regarding their accuracy in detecting Tumoral activity. Patients and Methods: The current study included 66 cases of Hepatocellular carcinoma (HCC) lesions underwent trans-arterial chemo-embolization procedure. Follow-up Dy-namic contrast enhanced MRI study (DCE-MRI) of the liver, dynamic subtraction technique and diffusion WIs were obtained 1 to 1.5 months post trans-arterial chemo-embolization. Results: Sensitivity of MRI subtraction in detection of the HCC recurrence=88.5%, with specificity in exclusion of recurrence=100%, PPV 100% and the NPV 70%. Regarding tumor activity there was a highly significant strong agreement between dynamic MRI and the MRI subtraction (p<0.001) and the k (Kappa)=0.765, Area of (95%CI) 0.942 ranging between (0.888-0.997). MRI diffusion Sensitivity of=71.2%, specificity=78.6%, PPV=92.5% and the NPV=42.3%. There was a significant weak agreement between the tumor activity by the dynamic MRI study and MRI diffusion (p=0.001) and the k=0.375, Area of (95%CI) 0.749 ranging between (0.604- 0.893). The mean ADC value of the Residual/recurrence enhanced tissue=1.437±0.4058 and the mean ADC value of necrotic tissues was 1.701±0.4408. The increased mean ADC in the necrotic tissue was statistically significant (p-value <0.001) with Area of (95%CI) 0.651 (0.462-0.840). Acute off equal to 1.374 of ADC value was found to predict the recur-rence with sensitivity=80.77%, specificity=57.14%, PPV= 87.5% and NP=44.4. Conclusion: We believe that the addition of subtraction images to the dynamic study combined with Diffusion WIs would be useful for post TACE evaluation of HCC. The data they yieldedwere complementary and consensus between DCEMRI, subtraction and diffusion WIs data should be made by the reader before final decision to be made.