Hepatic parenchymal changes after ethanol injection in rabbits: Correlation of conventional and dynamic MR imaging with pathologic findings

Abstract

The purpose of this study is to clarify the changes of peripheral normal liver parenchyma before and after ethanol injection, with respect to MR appearances and pathologic findings and, in so doing, to clinically evaluate the therapeutic effectiveness of percutaneous ethanol injection (PEI) therapy. The normal liver in 12 rabbits was injected with ethanol. We performed conventional and dynamic MR imaging and prepared the histopathologic specimens 1 week (group 1), 2 weeks (group 2), and 1 month (group 3) after ethanol injection. On conventional MR images, coagulative necrosis in the normal liver was demonstrated as an area of low signal intensity on T1-weighted images and high signal intensity on T2-weighted images in all groups. On dynamic MR images, contrast enhancement in the coagulative necrosis was not seen in groups 1 and 2; however, gradual and concentric enhancement was seen in the direction of the central necrotic portion from early-to-delayed phase image in group 3. Although signal intensity of the coagulative necrotic area in the normal liver after ethanol injection may mimic that of untreated or viable hepatocellular carcinoma (HCC) when clinically encountered on conventional MR images, coagulative necrosis of the normal liver parenchyma will be discriminated from viable HCC by using dynamic MR imaging.

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

“…The mechanism underlying this enhancement is presumably a combination of increased arterial supply, slow transit rate of blood, an extensive interstitial space, and changes in the diffusion rate between the interstitial and vascular spaces [11]. In our study of normal rabbits whose liver parenchyma was injected with ethanol [6], the same MR imaging and pathologic correlations were recognized.…”

“…However, to assess the therapeutic efficacy of PEI therapy correctly, it is also important to clarify the pathologic changes in the surrounding normal liver parenchyma seen at MR imaging before and after ethanol injection because ethanol is not always injected into only cancerous tissue, and it easily infiltrates into the surrounding normal liver parenchyma. Some investigators have reported changes in surrounding liver parenchyma on MR images after PEI therapy [3,6]. Fan-shaped hyperperfused areas were sometimes seen in the liver parenchyma adjacent to treated tumors on arterial-dominant-phase dynamic MR images within 1 month after PEI therapy [3].…”

“…However, the gradual enhancement from arterial-to delayed-phase images on dynamic MR study may be attributable to thick fibrous tissue. It is well established that fibrous tissue shows gradual, concentric enhancement on dynamic or contrast-enhanced T1-weighted MR images [6]. The mechanism underlying this enhancement is presumably a combination of increased arterial supply, slow transit rate of blood, an extensive interstitial space, and changes in the diffusion rate between the interstitial and vascular spaces [11].…”

Improved detection of metastases on magnetic resonance images by digital tissue recognition: Validation using VX‐2 tumor in the rabbit

“…Each rabbit was injected in four sites in the lumbar paraspinal muscles, the kidney, the liver, and in either the bladder or the spleen. In two rabbits, the liver and kidney were injected with pure ethanol (2.0 mL) to create areas of coagulative necrosis (21), which added the potential for false positive interpretations.…”

Trends in Contrast Media

“…Briefly, an alcohol injection is given to produce focal infarction in the tissue of interest under ultrasound guidance (FUJITA et al 1996). Briefly, an alcohol injection is given to produce focal infarction in the tissue of interest under ultrasound guidance (FUJITA et al 1996).…”