Subtraction MRI versus diffusion weighted imaging: Which is more accurate in assessment of hepatocellular carcinoma after Trans Arterial Chemoembolization (TACE)?

This study aims to compare the role of both subtraction MRI and Diffusion weighted images in assessment of HCC after trans-arterial chemo embolization (TACE). Patients and methods: 32 patients having 54 HCC lesions underwent TACE. Ages ranged between 59 and 73 years (mean age 59.6); there were 26 males and 6 females. All examinations were performed using Philips 1.5 T MRI (Achieva). Pre contrast: T1, T2W and In phase and out phase gradient echo sequence, dynamic: eTHRIVE technique performed. Subtraction of an unenhanced T1-weighted was from the identical post enhancement sequences in early angiographic and late arterial phases. Diffusion imaging: it was performed using single-shot spin-echo echo-planar imaging with b = 0, 300, 600 mm/s2. DWI was used to create ADC maps. Two readers blinded to each other assessed subtraction of dynamic study and DWI technique to evaluate post treatment response. Results: Reader 1 subtraction dynamic MRI sensitivity = 97%, specificity = 100% PPV = 100% and NPV = 95% compared to 70.59%, 75%, 82.76% and 60% respectively in DWI. Reader 2 subtraction dynamic MRI sensitivity = 97%, specificity = 100% PPV = 100% and NPV = 95% compared to 76.5%, 90%, 92.8% and 69% respectively in DWI. Conclusion: DW-MRI had lower accuracy measures compared to subtraction MRI with increased false negative. DWI may act as a supplementary sequence to compensate for the dynamic MRI in patients who couldn't hold their breath adequately.