CT appearance of multifocal hepatic steatosis

Multifocal hepatic steatosis mimicking malignancy in two siblings

Multifocal hepatic steatosis (MHS) is a rare subtype of hepatic steatosis which can pose a diagnostic challenge due to difficulty in distinguishing it from malignant disease. Steatotic nodules in MHS can vary in size from a few millimeters to several centimeters and may mimic hepatocellular carcinoma or metastases by both ultrasound and computed tomography assessment. Accurate detection of this abnormality is important and may prevent unnecessary investigation and biopsy, as well as anxiety for the patient. Here we present two cases of MHS occurring in adult siblings. The characteristic radiographic appearances of MHS will be described as well as tips provided for accurate detection. Given the rarity of this entity, the occurrence in two otherwise well adult siblings also raises the possibility of an inherited pathogenesis.

Multiple echogenic liver masses from multifocal nodular steatosis in a 55-year-old male with chronic hepatitis C

Hepatic steatosis is often seen in patients with hepatitis on screening ultrasound as generalized increased liver echogenecity. However, its nodular form can present as multiple echogenic masses, which can mimic hepatocellular carcinoma or metastasis by ultrasound and computed tomography. Small hepatocellular carcinomas are often hyperechoic and have a trend towards lower alpha-fetoprotein levels. Magnetic resonance imaging can accurately identify microscopic fat within the lesions and demonstrate lack of associated enhancing soft tissue. If this entity is not appropriately characterized using magnetic resonance imaging, it can lead to additional imaging workup and unnecessary biopsy.

Multinodular focal fatty infiltration of the liver: Atypical imaging findings on delayed T1-weighted Gd-BOPTA-enhanced liver-specific MR images

We report a case of pathologically confirmed multinodular focal fatty infiltration. MRI was performed after bolus injection of gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco, Milan, Italy), a liver-specific paramagnetic, gadolinium (Gd)-based MR contrast agent that concomitantly enables the acquisition of a standard dynamic phase with timing strategies similar to those used for other extracellular fluid contrast agents, followed by a delayed T1-weighted liver-specific phase (the so-called hepatobiliary phase). In the present case, multiple rounded areas of fatty infiltration, although confidently diagnosed using chemical shift sequences due to a significant signal intensity reduction on out-of-phase images, were unexpectedly hypointense during the delayed liver-specific phase of Gd-BOPTA. Reduced Gd-BOPTA concentration during the liver-specific phase is generally correlated with liver malignancy. Since such lesions can be prospectively mistaken for metastatic disease, we performed a hepatic biopsy to establish a definitive diagnosis. Our empirical observations suggest that Gd-BOPTA uptake may be impaired in fatty infiltrated liver tissue. Because at present there is no report evaluating the kinetics of Gd-BOPTA in fatty liver, further studies are needed to specifically investigate this issue.

Imaging Features of Perivascular Fatty Infiltration of the Liver: Initial Observations

PURPOSE

To retrospectively identify and describe the imaging features that represent perivascular fatty infiltration of the liver.

MATERIALS AND METHODS

The institutional review board approved the study and waived informed consent. The study complied with the Health Insurance Portability and Accountability Act. Ten patients (seven women, three men; mean age, 78 years; range, 31-78 years) with fatty infiltration surrounding hepatic veins and/or portal tracts were retrospectively identified by searching the abdominal imaging teaching file of an academic hospital. The patients' medical records were reviewed by one author. Computed tomographic (CT), magnetic resonance (MR), and ultrasonographic (US) imaging studies were reviewed by three radiologists in consensus. Fatty infiltration of the liver on CT images was defined as absolute attenuation less than 40 HU without mass effect and, if unenhanced images were available, as relative attenuation at least 10 HU less than that of the spleen; on gradient-echo MR images, it was defined as signal loss on opposed-phase images compared with in-phase images; and on US images, it was defined as hyperechogenicity of liver relative to kidney, ultrasound beam attenuation, and poor visualization of intrahepatic structures. Perivascular fatty infiltration of the liver was defined as a clear predisposition to fat accumulation around hepatic veins and/or portal tracts. For multiphase CT images, the contrast-to-noise ratio was calculated for comparison of spared liver with fatty liver in each imaging phase.

RESULTS

Fatty infiltration surrounded hepatic veins in three, portal tracts in five, and both hepatic veins and portal tracts in two patients. Six of the 10 patients had alcoholic cirrhosis, two reported regular alcohol consumption (one of whom had acquired immunodeficiency syndrome and hepatitis B), one was positive for human immunodeficiency virus, and one had no risk factors for fatty infiltration of the liver. In three of the 10 patients, fatty infiltration was misdiagnosed as vascular or neoplastic disease on initial CT images but was correctly diagnosed on MR images.

CONCLUSION

Perivascular fatty infiltration of the liver has imaging features that allow its recognition.

Focal fatty infiltration of the liver: analysis of prevalence and CT findings in children and young adults

OBJECTIVE

Focal fatty infiltration of the liver, a benign entity that can be confused with a malignant lesion, is well characterized in adults but not in children. The goal of this study was to determine by CT the prevalence and characteristics of focal fatty infiltration in children and young adults.

MATERIALS AND METHODS

We retrospectively analyzed 305 consecutive contrast-enhanced abdominal CT examinations of 218 children and young adults with no known liver disease, performed during 2 years at our institution, to identify focal fatty infiltration of the liver. The imaging criterion for focal fatty infiltration of the liver on helical CT was a geometric or ovoid low-attenuation area adjacent to the falciform ligament, gallbladder fossa, or porta hepatis. If a patient's findings met the CT criterion for focal fatty infiltration of the liver, all previous abdominal CT and MR imaging examinations performed for that patient were reviewed to assess the evolution of focal fatty infiltration of the liver.

RESULTS

Of 218 children and young adults, 20 (9.2%) met the CT criterion for focal fatty infiltration of the liver. In our population, focal fatty infiltration of the liver was identified only adjacent to the falciform ligament. The prevalence of focal fatty infiltration of the liver increased significantly with advancing age: 0% for ages 1 month-4 years; 7.3% for 5-9 years; 10.2% for 10-14 years, and 25.6% for 15-19 years (p < 0.0001).

CONCLUSION

Focal fatty infiltration of the liver was identified in 9.2% of patients in our population, and occurrence of this lesion in children increases significantly with advancing age. However, focal fatty infiltration of the liver is uncommon in infants and young children and should be a diagnosis of exclusion.

Imaging of diffuse liver disease

Imaging can play an important role in the diagnosis and planning of treatment for patients with diffuse liver disease. In certain entities, such as iron overload disorders, fatty change, Budd-Chiari syndrome, and schistosomiasis, the imaging findings are characteristic and diagnostic. In others, the findings are less specific, but imaging still has utility in assessment for associated changes of cirrhosis and portal hypertension. In either case, familiarity with these diffuse hepatic diseases and their expected imaging findings enables an organized and thoughtful assessment, with careful attention paid to the key diagnostic features and the important sequlae, such as portal hypertension and the development of HCC.

Focal fatty change of the liver. A review and a case associated with continuous ambulatory peritoneal dialysis

Focal fatty change (FFC) of a liver with unequivocal normal architecture is rare. A review of the literature revealed 39 histologically well-documented cases. Well-known steatogenic conditions were present in most of these cases. Focal ischaemia or a varying rate of mobilization of fat in the liver have been suggested as a cause of the focality of the lesions. FFC occurring in a diabetic patient on continuous ambulatory peritoneal dialysis (CAPD) is presented. The FFC in this and in ten previously reported cases associated with CAPD and intraperitoneal insulin therapy had a unique subcapsular distribution, which may suggest a specific pathogenetic mechanism involving insulin. The clinical significance of FFC in the differential diagnosis from other fatty lesions of the liver is summarized.