Chang Hee Lee

“Pseudo Washout” Sign in High-Flow Hepatic Hemangioma on Gadoxetic Acid Contrast-Enhanced MRI Mimicking Hypervascular Tumor

OBJECTIVEnThe purpose of this article is to describe the pseudo washout sign of high-flow hepatic hemangioma that mimics hypervascular tumor on gadoxetic acid-enhanced MRI.nnnCONCLUSIONnHigh-flow hemangiomas might show relatively low signal intensity because of gadoxetic acid contrast uptake in the surrounding normal liver parenchyma during the equilibrium (3-minute delay) phase. Such findings are called pseudo washout and can mimic hypervascular hepatic tumors. However, high-flow hemangioma can be diagnosed by observing bright signal intensity on T2-weighted imaging, arterial phase-dominant enhancement, pseudo washout sign during the equilibrium phase, and isointense or slightly increased signal intensity on subtraction images.

Comparison of the methods for tumor response assessment in patients with hepatocellular carcinoma undergoing transarterial chemoembolization

BACKGROUND & AIMSnRecently, new methods, including the concept of viable enhancing tumor such as EASL and mRECIST, have been proposed for substitution of the conventional WHO and RECIST criteria in hepatocellular carcinoma (HCC) undergoing transarterial chemoembolization (TACE). Herein, we evaluated the differences of four methods and compared the association of these methods with the prognosis of HCC patients undergoing TACE.nnnMETHODSnWe retrospectively reviewed 114 consecutive newly diagnosed HCC patients who underwent TACE as initial treatment. We evaluated the intermethod agreement (κ values) between the methods and compared their association with the prognosis of HCC patients.nnnRESULTSnThe κ values for EASL vs. WHO, EASL vs. RECIST, mRECIST vs. WHO, and mRECIST vs. RECIST were low, of 0.102, 0.088, 0.112, and 0.122, respectively. However, good correlations were observed for WHO vs. RECIST and EASL vs. mRECIST (κ=0.883, κ=0.759, respectively p<0.001). The median OS was 32.3 months. Hazard ratios (HR) for survival in responders compared with non-responders were 0.21 (95% CI; 0.12-0.37, p<0.001) for EASL and 0.27 (95% CI; 0.15-0.48, p<0.001) for mRECIST. The mean survival of responders was significantly longer than that of non-responders in both EASL (40.8 vs. 16.9 months, p<0.001) and mRECIST (41.1 vs. 20.7 months, p<0.001). In multivariate analysis, EASL response (HR 0.21, 95% CI 0.11-0.40, p<0.001) and mRECIST response (HR; 0.31, 95% CI, 0.17-0.59, p<0.001) were independently associated with survival.nnnCONCLUSIONSnThe response assessment by EASL and mRECIST could reliably predict the survival of HCC patients undergoing TACE and could be applicable in practice in preference to the conventional WHO and RECIST criteria.

Increased Selenoprotein P Levels in Subjects with Visceral Obesity and Nonalcoholic Fatty Liver Disease

Background Selenoprotein P (SeP) has recently been reported as a novel hepatokine that regulates insulin resistance and systemic energy metabolism in rodents and humans. We explored the associations among SeP, visceral obesity, and nonalcoholic fatty liver disease (NAFLD). Methods We examined serum SeP concentrations in subjects with increased visceral fat area (VFA) or liver fat accumulation measured with computed tomography. Our study subjects included 120 nondiabetic individuals selected from participants of the Korean Sarcopenic Obesity Study. In addition, we evaluated the relationship between SeP and cardiometabolic risk factors, including homeostasis model of insulin resistance (HOMA-IR), high sensitivity C-reactive protein (hsCRP), adiponectin values, and brachial-ankle pulse wave velocity (baPWV). Results Subjects with NAFLD showed increased levels of HOMA-IR, hsCRP, VFA, and several components of metabolic syndrome and decreased levels of adiponectin and high density lipoprotein cholesterol than those of controls. Serum SeP levels were positively correlated with VFA, hsCRP, and baPWV and negatively correlated with the liver attenuation index. Not only subjects with visceral obesity but also those with NAFLD exhibited significantly increased SeP levels (P<0.001). In multiple logistic regression analysis, the subjects in the highest SeP tertile showed a higher risk for NAFLD than those in the lowest SeP tertile, even after adjusting for potential confounding factors (odds ratio, 7.48; 95% confidence interval, 1.72 to 32.60; P=0.007). Conclusion Circulating SeP levels were increased in subjects with NAFLD as well as in those with visceral obesity and may be a novel biomarker for NAFLD.

Crystal Structure and Microwave Dielectric Properties of CaTiO3–(Li1/2Nd1/2) TiO3–(Ln1/3Nd1/3)TiO3 (Ln=La, Dy) Ceramics

Crystal structure and microwave dielectric properties of a xCaTiO3–y(Li1/2Nd1/2)TiO3–z(Ln1/3Nd1/3)TiO3 (Ln=La, Dy) ternary system were studied. Crystal structures were refined by the Rietveld method using X-ray and neutron diffraction data. (Li1/2Nd1/2)TiO3 and 0.2CaTiO3–0.8(La1/3Nd1/3)TiO3 ceramics showed the most reliable R-values with a tetragonal structure with a space group P-4b2 and lattice constants of a=b≈5.4 A, and c≈7.6 A. The A-site cations were ordered along the c-axis. When x≥0.3, the crystal structure changed to an orthorhombic CaTiO3 type. The xCaTiO3–y(Li1/2Nd1/2)TiO3–z(La1/3Nd1/3)TiO3 system showed microwave dielectric properties of er=133, Qf=1,450 GHz and τf=-17 ppm/°C at a composition of x=0.2, y=0.68, z=0.12. In xCaTiO3–y(Li1/2Nd1/2)TiO3–z(Dy1/3Nd1/3)TiO3, dielectric properties of er=97.6, Qf=5,150 GHz and τf=+0.4 ppm/°C were obtained at x=0.30, y=0.40, z=0.30. The effect of each ternary system component on the dielectric properties is discussed.

Typical and atypical imaging findings of intrahepatic cholangiocarcinoma using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging.

Purpose The objective of this study was to examine the imaging features of classic mass-forming intrahepatic cholangiocarcinoma (MICC) and nonclassic hypervascular MICC on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid–enhanced magnetic resonance imaging. Methods Twenty pathologically confirmed MICCs were included. Two radiologists retrospectively reviewed the imaging characteristics on T2-weighted imaging, diffusion-weighted imaging, dynamic contrast-enhanced images, and hepatobiliary phase (HBP) of each MICC. For the morphologic feature of defect, HBP signal intensity (SI) ratio was calculated by dividing the SI of the MICC by nearby normal liver parenchyma SI. Results Classic MICCs (n = 14) showed classic rim or peripheral enhancement at arterial dominant phase with centripetal enhance in the delayed phases. Hypervascular MICCs (n = 6) showed complete (n = 4) or near-complete (n = 2) arterial enhancement and washout (n = 6) on delayed phases. On HBP, 13 classic MICCs (93%) and 2 hypervascular MICCs (33%) showed cloud-like SI in the center (“EOB cloud”) with peripheral defect. Mean SI ratio was 0.77 in classic MICCs and 0.59 in hypervascular MICC (P = 0.057). Conclusions Classic MICCs (70%) frequently showed progressive centripetal enhancement on dynamic phase, and central EOB-cloud appearance with distinct peripheral defect on HBP. Nonclassic hypervascular MICCs comprised 30% of the MICCs in this study. Compared with classic MICCs, hypervascular MICCs showed wash-in on arterial dominant phase and washout on delayed phase.

Usefulness of controlled aliasing in parallel imaging results in higher acceleration in gadoxetic acid-enhanced liver magnetic resonance imaging to clarify the hepatic arterial phase.

PurposeWe aimed to determine whether the controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique could improve the image quality of the hepatic arterial phase of gadoxetic acid–enhanced liver magnetic resonance (MR) imaging. Materials and MethodsA total of 320 patients underwent gadoxetic acid–enhanced liver MR imaging: a conventional protocol (a fixed scan delay and 2-mL/s injection) using a standard 3-T MR system (Trio-Tim; Siemens, commercialized since 2005) (group A), an optimized protocol (bolus tracking and 1-mL/s injection) using a standard 3-T MR (group B), an optimized protocol using a new 3-T MR (Skyra; Siemens, commercialized since 2012) (group C), and an optimized protocol with CAIPIRINHA using a new 3-T MR (group D). The image quality of the hepatic arterial phase was graded using a 4-point rating scale from 1 (no artifacts) to 4 points (non–diagnostic images with severe artifacts). The differences in image quality scores among the 4 groups were evaluated. In addition, the detection rates of hypervascular hepatocellular carcinomas among the 4 groups were evaluated. ResultsScores of 4 points were observed in groups A (n = 7), B (n = 5), and C (n = 3) but not in group D. The median image quality score was 2 in groups A and B and 1 in groups C and D. From group A to group D, the median image quality score decreased significantly (P = 0.0001). The median image quality score was significantly lower in group D than in groups A and B (P = 0.0001 and 0.001, respectively), whereas there was no significant difference observed between groups C and D (P = 0.656). The detection rates of hypervascular hepatocellular carcinomas on the hepatic arterial phase were not significantly different among the groups (all P > 0.03), except between groups A and D (P = 0.007). ConclusionsThe CAIPIRINHA technique improved the image quality of hepatic arterial phase imaging with gadoxetic acid, reducing the number of non–diagnostic arterial phase studies.

Cutoff points of abdominal obesity indices in screening for non-alcoholic fatty liver disease in Asians.

Background/aims: Abdominal obesity is associated with metabolic syndrome and non‐alcoholic fatty liver disease (NAFLD). Although there have been many studies to determine the optimal cutoff points of waist circumference or visceral fat area in screening for metabolic syndrome, there have been no reports to establish adequate cutoff points of abdominal obesity indices in screening for NAFLD. Therefore, we examined the appropriate cutoff points of abdominal obesity indices associated with NAFLD in Korean men and women using receiver operating characteristic (ROC) curve analysis. Furthermore, we compared the usefulness of various abdominal obesity indices measured using computed tomography (CT), dual‐energy X‐ray absorptiometry (DXA) and anthropometric parameters for detecting NAFLD.

Using intravoxel incoherent motion (IVIM) MR imaging to predict lipiodol uptake in patients with hepatocellular carcinoma following transcatheter arterial chemoembolization: A preliminary result☆

PURPOSEnTo assess the usefulness of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) for predicting lipiodol uptake in patients with hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE).nnnMATERIALS AND METHODSnThe institutional review board approved this study. 44 HCC patients underwent IVIM-DWI and Gd-EOB-DTPA-enhanced MRI prior to TACE. Using post-TACE CT as a reference standard, each HCC was classified into either lipiodol good uptake (LGU) or poor uptake (LPU) group. Apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f) in HCC were calculated. Arterial enhancement ratio (AER) and IVIM parameters were compared between those two groups using the Mann-Whitney U test.nnnRESULTSnOf the 51 HCCs, 37 (72.5%) were LGU group and 14 (27.5%) were LPU group. AER of HCC was significantly higher in LGU than LPU (0.99±0.54 and 0.67±0.45; P=.034). ADC, D, and f values were not significantly different (P=.073, .059, and .196, respectively) between these two groups. D* was significantly elevated in LGU than LPU (48.10±15.33 and 26.75±9.55; P=.001).nnnCONCLUSIONnBoth AER derived from contrast enhanced MRI and D* values derived from IVIM-DWI for HCC were significantly higher in LGU than in LPU. These parameters would be helpful for predicting the lipiodol uptake.

Prediction of liver cirrhosis, using diagnostic imaging tools

Early diagnosis of liver cirrhosis is important. Ultrasound-guided liver biopsy is the gold standard for diagnosis of liver cirrhosis. However, its invasiveness and sampling bias limit the applicability of the method. Basic imaging for the diagnosis of liver cirrhosis has developed over the last few decades, enabling early detection of morphological changes of the liver by ultrasonography (US), computed tomography, and magnetic resonance imaging (MRI). They are also accurate diagnostic methods for advanced liver cirrhosis, for which early diagnosis is difficult. There are a number of ways to compensate for this difficulty, including texture analysis to more closely identify the homogeneity of hepatic parenchyma, elastography to measure the stiffness and elasticity of the liver, and perfusion studies to determine the blood flow volume, transit time, and velocity. Amongst these methods, elastography using US and MRI was found to be slightly easier, faster, and able to provide an accurate diagnosis. Early diagnosis of liver cirrhosis using MRI or US elastography is therefore a realistic alternative, but further research is still needed.

The short breath-hold technique, controlled aliasing in parallel imaging results in higher acceleration, can be the first step to overcoming a degraded hepatic arterial phase in liver magnetic resonance imaging: A prospective randomized control study

ObjectiveThe aim of this study was to assess whether a short breath-hold technique can improve hepatic arterial phase (HAP) image quality in gadoxetic acid–enhanced magnetic resonance (MR) imaging compared with a conventional long breath-hold technique. Materials and MethodsInstitutional review board approval and patient consent were obtained for this prospective randomized control study. One hundred nineteen patients undergoing gadoxetic acid–enhanced MR imaging were randomly assigned to groups A or B. Group A patients underwent an 18-second long breath-hold MR technique (conventional VIBE [volumetric interpolated breath-hold examination] technique with GRAPPA [generalized autocalibrating partially parallel acquisition]), and group B patients underwent a 13-second short breath-hold MR technique (VIBE technique with CAIPIRINHA [controlled aliasing in parallel imaging results in higher acceleration]). Respiratory-related graphs of the precontrast and HAP were acquired. The breath-hold degree was graded based on the standard deviation (SD) value of respiratory waveforms. Gadoxetic acid–related dyspnea was defined as when the SD value of the HAP was 200 greater than that of the precontrast phase without degraded image quality in the portal and transitional phases (SD value of the HAP − SD value of the precontrast phase). The overall image quality and motion artifacts of the precontrast and HAP images were evaluated. The groups were compared using the Student t or Fisher exact test, as appropriate. ResultsThe incidence of breath-holding difficulty (breath-hold grades 3 and 4) during the HAP was 43.6% (27/62) and 36.8% (21/57) for group A and B, respectively. The SD value during the precontrast phase and the SD value difference between the precontrast and HAP were both significantly higher in group A than in group B (P = 0.047 and P = 0.023, respectively). Gadoxetic acid–related dyspnea was seen in 19.4% (12/62) of group A and 7.0% (4/57) of group B. Group B showed better precontrast and HAP image quality than group A (P < 0.001). Degraded HAP (overall image quality ≥4) was observed in 9.7% (6/62) and 3.5% (2/57) of group A and B, respectively. ConclusionsThe short breath-hold MR technique, CAIPIRINHA, showed better HAP image quality with less degraded HAP and a lower incidence of breath-hold difficulty and gadoxetic acid–related dyspnea than the conventional long breath-hold technique.