Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography

AIM:To clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT). METHODS:Twenty-six patients with 61 hepatic hem- angiomas who underwent both Gd-EOB-DTPA-enhanced MRI and enhanced CT were retrospectively reviewed. Hemangioma appearances (presence of peripheral nodular enhancement, central nodular enhancement, diffuse homogenous enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and prolonged enhancement during the equilibrium phase) on Gd-EOB-DTPA-enhanced MRI and enhanced CT were evaluated.The degree of contrast enhancement at the enhancing portion within the hemangioma was visually assessed using a five-point scale during each phase. For quantitative analysis, the tumor-muscle signal intensity ratio (SIR), the liver-muscle SIR, and the attenuation value of the tumor and liver parenchyma were calculated. The McNemar test and the Wilcoxon's signed rank test were used to assess the significance of differences in the appearances of hemangiomas and in the visual grade of tumor contrast enhancement between Gd-EOB-DTPA-enhanced MRI and enhanced CT. RESULTS:There was no significant difference between Gd-EOB-DTPA-enhanced MRI and enhanced CT in the presence of peripheral nodular enhancement (85% vs 82%), central nodular enhancement (3% vs 3%), diffuse enhancement (11% vs 16%), or arterioportal shunt (23% vs 34%) during arterial phase, or fill-in enhancement (79% vs 80%) during portal venous phase. Prolonged enhancement during equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than on enhanced CT (52% vs 100%, P < 0.001). On visual inspection, there was significantly less contrast enhancement of the enhancing portion on Gd-EOB-DTPA-enhanced MRI than on enhanced CT during the arterial (3.94 ± 0.98 vs 4.57 ± 0.64, respectively, P < 0.001), portal venous (3.72 ± 0.82 vs 4.36 ± 0.53, respectively, P < 0.001), and equilibrium phases (2.01 ± 0.95 vs 4.04 ± 0.51, respectively, P < 0.001). In the quantitative analysis, the tumor-muscle SIR and the liver-muscle SIR observed with Gd-EOB-DTPA-enhanced MRI were 0.80 ± 0.24 and 1.28 ± 0.33 precontrast, 1.92 ± 0.58 and 1.57 ± 0.55 during the arterial phase, 1.87 ± 0.44 and 1.73 ± 0.39 during the portal venous phase, 1.63 ± 0.41 and 1.78 ± 0.39 during the equilibrium phase, and 1.10 ± 0.43 and 1.92 ± 0.50 during the hepatobiliary phase, respectively. The attenuation values in the tumor and liver parenchyma observed with enhanced CT were 40.60 ± 8.78 and 53.78 ± 7.37 precontrast, 172.66 ± 73.89 and 92.76 ± 17.92 during the arterial phase, 152.76 ± 35.73 and 120.12 ± 18.02 during the portal venous phase, and 108.74 ± 18.70 and 89.04 ± 7.25 during the equilibrium phase, respectively. Hemangiomas demonstrated peak enhancement during the arterial phase, and both the SIR with Gd-EOB-DTPA-enhanced MRI and the attenuation value with enhanced CT decreased with time. The SIR of hemangiomas was lower than that of liver parenchyma during the equilibrium and hepatobiliary phases on Gd-EOB-DTPA-enhanced MRI. However, the attenuation of hemangiomas after contrast injection was higher than that of liver parenchyma during all phases of enhanced CT. CONCLUSION:Prolonged enhancement during the equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than enhanced CT, which may exacerbate differentiating between hemangiomas and malignant tumors.

Computed tomography and magnetic resonance imaging features of lipid-rich neuroendocrine tumors of the pancreas

AIM:To clarify the computed tomography(CT) and magnetic resonance imaging(MRI) characteristics of lipid-rich pancreatic neuroendocrine tumors(Pan NETs).METHODS:Enhanced CT and MRI performed before pancreatectomy in 29 patients with 34 histologicallyconfirmed Pan NETs was retrospectively reviewed. Tumor attenuation on CT and signal intensities on conventional(T1- and T2-weighted) and chemical shift MRI were qualitatively analyzed and compared alongside adipose differentiation-related protein(ADRP) immunostaining(ADRP-positive:lipid-rich; ADRP-negative:non-lipid-rich) results using Fisher's exact test or the Mann-Whitney U test. Signal intensity index on chemical shift MRI was quantitatively assessed.RESULTS:There were 15 lipid-rich Pan NETs(44.1%) in 12 patients(41.4%). Tumor attenuation during the early,portal venous,and delayed phases of enhanced CT(P = 0.888,0.443,and 0.359,respectively) and signal intensities on conventional MRI(P = 0.698 and 0.798,respectively) were not significantly differentbetween lipid-rich and non-lipid-rich Pan NETs. Four of the 15 lipid-rich Pan NETs exhibited high signal intensity on subtraction chemical shift MRI,and the association of high signal intensity on subtraction imaging with lipid-rich Pan NETs was significant(4 of 15 lipid-rich Pan NETs,26.73%,vs 0 of 19 non-lipid-rich Pan NETs,0%,P = 0.029). Lipid-rich Pan NETs showed a significantly higher signal intensity index than non-lipidrich Pan NETs(0.6% ± 14.1% vs-10.4% ± 14.4%,P = 0.004). Eight of 15 lipid-rich Pan NETs,vs 0 of 19 nonlipid-rich Pan NETs,had positive signal intensity index values in concordance with lipid contents.C O N C L U S I O N :C T c o n t ra s t e n h a n c e m e n t a n d conventional MR signal intensities are similar in lipidrich and non-lipid-rich Pan NETs. Chemical shift MRI can demonstrate cytoplasmic lipids in Pan NETs.