Comparison of magnetic resonance spectroscopy, proton density fat fraction and histological analysis in the quantification of liver steatosis in children and adolescents.

AIM: To establish a threshold value for liver fat content between healthy children and those with non-alcoholic fatty liver disease (NAFLD) by using magnetic resonance imaging (MRI), with liver biopsy serving as a reference standard. METHODS: The study was approved by the local ethics committee, and written informed consent was obtained from all participants and their legal guardians before the study began. Twenty-seven children with NAFLD underwent liver biopsy to assess the presence of nonalcoholic steatohepatitis. The assessment of liver fat fraction was performed using MRI, with a high field magnet and 2D gradient-echo and multiple-echo T1-weighted sequence with low flip angle and single-voxel point-resolved ¹H MR-Spectroscopy (¹H-MRS), corrected for T1 and T2* decays. Receiver operating characteristic curve analysis was used to determine the best cut-off value. Lin coefficient test was used to evaluate the correlation between histology, MRS and MRI-PDFF. A Mann-Whitney U-test and multivariate analysis were performed to analyze the continuous variables. RESULTS: According to MRS, the threshold value between healthy children and those with NAFLD is 6%; using MRI-PDFF, a cut-off value of 3.5% is suggested. The Lin analysis revealed a good fit between the histology and MRS as well as MRI-PDFF. CONCLUSION: MRS is an accurate and precise method for detecting NAFLD in children.

Hepatocellular carcinoma (HCC) in non-cirrhotic liver: clinical, radiological and pathological findings.

OBJECTIVES: Our aim was to evaluate the clinical and pathological findings, mutidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI) appearances, treatment and 1-year survival of patients with HCC in non-cirrhotic liver. METHODS: Histopathological and laboratory findings of 30 non-cirrhotic patients with 32 HCCs were reviewed retrospectively. MDCT and gadobenate dimeglumine-enhanced MR images were evaluated in consensus by two radiologists in terms of HCC size, presence of tumour capsule, necrosis, haemorrhage, fat and calcification, and vascular involvement. Imaging patterns were compared directly with HCC findings in a matched group of cirrhotic patients. RESULTS: No differences between non-cirrhotic and cirrhotic patients were noted in terms of serum α-fetoprotein levels (elevated in 11 [36.7%] and 21 [35%] patients, respectively). The imaging appearance at CT and contrast-enhanced MRI was typical in 27 (84.3%) and 28 (87.5%) cases respectively. Most lesions presented as a well-differentiated large solitary mass, with well-defined margins, areas of necrosis and peripheral capsule. No significant differences in HCC pattern were observed between cirrhotic and non-cirrhotic liver. CONCLUSIONS: In non-cirrhotic patients, HCC is more likely to manifest as an asymptomatic mass with elevation of serum tumour markers similar to that seen in cirrhotic patients. HCC in cirrhotic and non-cirrhotic livers show similar enhancement patterns. KEY POINTS: HCC shows similar CT/MRI pattern in cirrhotic and non-cirrhotic livers. Non-invasive diagnostic criteria for HCC should also be extended to non-cirrhotic livers. No differences were found between α-fetoprotein levels in non-cirrhotic and cirrhotic patients.

Detection of small (≤2 cm) HCC in cirrhotic patients: added value of diffusion MR-imaging.

OBJECTIVES: To evaluate the usefulness of the diffusion-weighted sequence in the detection of small (≤2 cm) hepatocellular carcinoma (HCC) in patients with cirrhosis. METHODS: Seventy cirrhotic patients with 93 HCCs underwent MR-Imaging at 1.5 T. MR acquisitions comprised unenhanced T1- and T2-weighted images and post-contrast Gd-BOPTA-enhanced T1W GRE-3D images acquired after approximately 25, 60, 180 s (dynamic phases) and 90 min (hepatobiliary phase). DWI was performed by a SSEPI sequence (b values 0, 50, 400, 800 s/mm(2)). Quantitative analysis was performed to establish significant difference of ADC values of benign lesions compared with that of HCC. Sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of two different protocols with and without diffusion MRI sequence were also calculated and compared each other. RESULTS: A good inverse correlation was found between reference standard and ADC values (ρ = -0.688). The mean ADC value of HCC was significantly lower than the mean value of benign focal liver lesions (p < 0.0001). No significant difference was reported in term of sensitivity, specificity, PPV, NPV and diagnostic accuracy between the two datasets. A trend to a better sensitivity was found when DWI images were considered. CONCLUSIONS: The adjunction of DWI does not significantly improve the diagnostic accuracy in the detection of small HCC.