Focal sparing in fatty infiltration of the liver

Abstract

Four cases of focal sparing in otherwise diffuse fatty infiltration of the liver are reported. The characteristic features are described as shown at sonography, computed tomography (CT) and scintigraphy. It is emphasised that, with ultrasound, if the increased echogenicity of the majority of the liver is not appreciated, then the area of normal hepatic parenchyma may be misinterpreted as a pathological hypoechoic lesion.

Diagnosis of fatty infiltration of the liver on contrast enhanced CT: limitations of liver-minus-spleen attenuation difference measurements

“…Moderate and severe fatty liver were more accurately diagnosed by L-S attenuation difference measurements; however, these cases are often easily diagnosed on CECT by subjective evaluation alone. Subjective observation of a pronounced L-S attenuation difference or recognition of additional clues such as ''focal sparing'' [22][23][24][25] will likely remain the most practical methods for diagnosing fatty infiltration on CECT. Noncontrast CT is probably a more reliable standard for the detection of fatty infiltration of the liver, and preliminary noncontrast images should be obtained if more accurate diagnosis of fatty liver is an important clinical or research concern.…”

Focal sparing in the fatty liver as a sign of an adjacent space-occupying lesion.

“…Conversely, â€oe¿ spared― areas of normal liver parenchymawithin the otherwise diffusely steatotic liver may be misinterpreted asabnormal [3]. The term â€oe¿ pseudotumors― has beenusedsometimesto describeboth the het erogeneousfat deposits in the liver and the focal sparedareasto stressthat they arebenign entities despite their ominous appearance.…”

Differentiation between true focal liver lesions and pseudolesions in patients with fatty liver: evaluation of helical CT criteria

“…However, there have been some reports that have emphasised that pseudolesions in fatty liver may have an atypical and equivocal appearance [17][18][19]. Therefore, in some cases, focal spared areas may be misinterpreted as true lesions, thus leading to incorrect patient management or additional examinations, including liver biopsy, to ascertain the diagnosis [19,20]. Conversely, when a true lesion is present, its definitive characterisation may be challenging on imaging examination when the liver is diffusely fatty [21][22][23][24].…”