Dae Jung Kim MD, Presenter: Nothing to Disclose

Jeong-Sik Yu MD, Abstract Co-Author: Nothing to Disclose

Joo Hee Kim, Abstract Co-Author: Nothing to Disclose

Jae-Joon Chung MD, Abstract Co-Author: Nothing to Disclose

To compare the value of diffusion-weighted MRI (DWI) with the venous “washout” appearance during the dynamic MRI in the assessment of small hypervascular lesions in the cirrhotic liver.

A total of 109 small hypervascular lesions (0.5-3 cm) in 65 cirrhotic patients, who underwent gadolinium-enhanced dynamic MR imaging and DWI (b =50,400,800 s/mm2) at 1.5T unit during a 16-month period, were retrospectively analyzed to determine presence of “washout” appearance in portal or equilibrium phase during dynamic imaging and sustaining hyperintensity regardless of b values on DWI. Ninty-nine lesions were verified as hepatocelular carcinomas (HCCs) histologically (n=21) or by serial follow-up (lipiodol deposition after chemoembolization or more than 20% increase in diameter,n=78). Hypervascular benign or pseudolesions (n=10) were diagnosed by serial follow-up(no change or spontaneous disappearance). According to the longest dimension of each lesion measured on the arterial phase images of dynamic MRI(<10 mm,n=35; 10–14 mm,n=27; 15–20 mm,n=22; >20 mm,n=25), relative prevalence of the two imaging features were compared each other using McNemar test in four separate groups. A likelihood ratio chi-squared test was performed to evaluate correlation between lesion size and presence of “washout” on dynamic imaging or hyperintensity on DWI.

Among 99 hypervascular HCCs, sustaining hyperintensity on DWI (92/99, 93%) was more prevalent than “washout” appearance (77/99, 78%) on the dynamic MRI (p<0.05). Depending on size of lesions, subcentimeter HCCs had a significantly lower prevalence of venous “washout” (18/30, 60%) compared with the sustaining hyperintensity on DWI (27/30, 90%) (p=0.035). The lager lesion, prevalence of “washout” was higher (p<0.001) while there was no different prevalence of the sustaining hyperintensity on DWI (p=0.11) according to lesion size(Fig). In all 10 hypervascular benign or pseudolesions, there was no venous washout on dynamic imaging and sustaining hyperintensity on DWI.

Compared with the “washout” appearance during the dynamic imaging,DWI would provide more reliable information in the MRI assessment of small hypervascular HCCs distinguished from the hypervascular benign or pseudolesions.

DWI could considerably complement the early diagnosis of small hypervascular HCCs that do not display venous washout during the gadolinium-enhanced dynamic imaging.

Kim, D, Yu, J, Kim, J, Chung, J, Small Hypervascular Hepatocellular Carcinomas: Value of Diffusion-weighted Imaging Compared with “Washout” Appearance on Dynamic MRI.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9014081.html