Nondiffuse fatty change of the liver: Discerning pseudotumor on MR images enhanced with ferumoxides initial observations

PURPOSE: To clarify the findings of nondiffuse fatty change of the liver on ferumoxides-enhanced magnetic resonance (MR) images. MATERIALS AND METHODS: Of 202 patients who underwent ferumoxides-enhanced M R imaging, eight who had nondiffuse fatty change of the liver at computed t omography (CI) were examined as study subjects. MR imaging findings before and 1 hour after ferumoxides administration were compared with CF findings. RESULTS: Focal fatty areas of the liver showing low attenuation-on CT image s were depicted as areas of relatively high intensity on the ferumoxides-en hanced T1-weighted images in ail patients. On enhanced T2-weighted images, focal fatty change showed relatively high intensity in three and isointensi ty in one of the four patients. Focal spared areas appearing as areas of re latively-high attenuation on Cf images were depicted as areas of relatively low intensity on the ferumoxides-enhanced T1- and T2-weighted images in al l patients. CONCLUSION: Although prior reports of hepatic MR imaging with ferumoxides i ndicated that there is accumulation of ferumoxides within focal fatty areas that are no longer seen after the administration of contrast medium, this study: revealed that focal fatty change and focal spared areas Of fatty liv er may-be pseudotumors because of the relatively high intensity of fatty ar eas of the liver. Radiologists can distinguish these condition; from hepati c tumors by using the opposed-phase ii gradient-echo sequence or the fat-sa turation technique.