Sanghyeok Lim

Sarcopenia as a Useful Predictor for Long-Term Mortality in Cirrhotic Patients with Ascites

This study aimed to assess and compare sarcopenia with other prognostic factors for predicting long-term mortality in cirrhotic patients with ascites. Clinical data of 65 among 89 patients with measurement of all parameters were consecutively collected. Sarcopenia was evaluated as right psoas muscle thickness measurement divided by height (PMTH) (mm/m). During a mean follow-up of 20 (range: 1-49) months, 19 (29.2%) of 65 patients died. The values of the area under the receiver operating characteristics curve (AUROC) of Child-Pugh score, Model for End-Stage Liver Disease (MELD) score, MELD-Na, and PMTH for predicting 1-yr mortality were 0.777 (95% CI, 0.635-0.883), 0.769 (95% CI, 0.627-0.877), 0.800 (95% CI, 0.661-0.900), and 0.833 (95% CI, 0.699-0.924), whereas hepatic venous pressure gradient was not significant (AUROC, 0.695; 95% CI. 0.547-0.818, P=0.053). The differences between PMTH and other prognostic variables were not significant (all P>0.05). The best cut-off value of PMTH to predict long-term mortality was 14 mm/m. The mortality rates at 1-yr and 2-yr with PMTH>14 mm/m vs. PMTH≤14 mm/m were 2.6% and 15.2% vs. 41.6% and 66.8%, respectively (P<0.001). The mortality in cirrhotic patients with PMTH≤14 mm/m was higher than those with PMTH>14 mm/m (HR, 5.398; 95% CI, 2.111-13.800, P<0.001). In conclusion, sarcopenia, evaluated by PMTH, is an independent useful predictor for long-term mortality in cirrhotic patients with ascites. Graphical Abstract

Fusion imaging-guided percutaneous biopsy of focal hepatic lesions with poor conspicuity on conventional sonography.

The purpose of this study was to evaluate the effectiveness of real‐time fusion imaging (sonography combined with computed tomography or magnetic resonance imaging) for percutaneous sonographically guided biopsy of focal hepatic lesions with poor sonographic conspicuity.

Prediction of microvascular invasion of hepatocellular carcinomas with gadoxetic acid-enhanced MR imaging: Impact of intra-tumoral fat detected on chemical-shift images

PURPOSE To investigate the impact of intra-tumoral fat detected by chemical-shift MR imaging in predicting the MVI of HCC. MATERIALS AND METHODS Gadoxetic acid-enhanced MR imaging of 365 surgically proven HCCs from 365 patients (306 men, 59 women; mean age, 55.6 years) were evaluated. HCCs were classified into two groups, fat-containing and non-fat-containing, based on the presence of fat on chemical-shift images. Fat-containing HCCs were subdivided into diffuse or focal fatty change groups. Logistic regression analyses were used to identify clinical and MR findings associated with MVI. RESULTS Based on MR imaging, 66 tumors were classified as fat-containing HCCs and 299 as non-fat-containing HCCs. Among the 66 fat-containing HCCs, 38 (57.6%) showed diffuse fatty changes and 28 (42.4%) showed focal fatty changes. MVI was present in 18 (27.3%) fat-containing HCCs and in 117 (39.1%) non-fat-containing HCCs (P=0.07). Univariate analysis revealed that serum alpha-fetoprotein (AFP) and tumor size were significantly associated with MVI (P<0.001). A multiple logistic regression analysis showed that log AFP (odds ratio 1.178, P=0.0016), tumor size (odds ratio 1.809, P<0.001), and intra-tumoral fat (odds ratio 0.515, P=0.0387) were independent variables associated with MVI. CONCLUSION Intra-tumoral fat detected with MR imaging may suggest lower risk for MVI of HCC and, therefore, a possibly more favorable prognosis, but the clinical value of this finding is uncertain.

Value of Diffusion-Weighted MRI for Differentiating Malignant From Benign Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE The purpose of this study was to evaluate whether the use of diffusion-weighted MRI (DWI) increases diagnostic accuracy in the differentiation of malignant from benign intraductal papillary mucinous neoplasms (IPMNs) of the pancreas over the accuracy of contrast-enhanced MRI with MRCP. MATERIALS AND METHODS A total of 61 patients with surgically resected IPMNs (19 malignant, 42 benign) who underwent gadoxetic acid-enhanced MRI, DWI, and MRCP were included. Two blinded observers evaluated two image sets, that is, conventional MRI with MRCP images versus combined conventional MRI with MRCP and DW images, and scored their confidence for malignancy of IPMNs. Qualitative analyses of the IPMNs were also conducted. Diagnostic performance (ROC curve analysis), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated. The Fisher exact test was used to compare groups. RESULTS The diagnostic performance (area under the ROC curve [Az]) with respect to predicting malignancy of IPMNs improved significantly for both observers after additional review of DW images (p < 0.05). The diagnostic accuracy, sensitivity, specificity, PPV, and NPV of combined conventional and DW images were higher than those of conventional MR images alone. Diffusion restriction was more often present in malignant IPMNs (78.9%) than in benign IPMNs (16.7%) (p < 0.001) with excellent interobserver agreement (ĸ = 0.965). CONCLUSION Compared with conventional MRI alone, adding DWI to conventional MRI improves diagnostic accuracy with increased specificity for differentiating malignant from benign IPMNs of the pancreas.

Hilar Cholangiocarcinoma: Value of Adding DW Imaging to Gadoxetic Acid–enhanced MR Imaging with MR Cholangiopancreatography for Preoperative Evaluation

PURPOSE To assess the benefit of adding diffusion-weighted (DW) imaging to gadoxetic acid-enhanced magnetic resonance (MR) imaging and MR cholangiopancreatography in the preoperative evaluation of hilar cholangiocarcinoma. MATERIALS AND METHODS The institutional review board approved this retrospective study and waived the requirement for informed consent. The study included 52 patients (36 men, 16 women; mean age, 63.4 years) with surgically confirmed hilar cholangiocarcinoma who underwent gadoxetic acid-enhanced MR imaging and DW imaging at 3.0 T between August 2010 and December 2011. Two observers independently reviewed two image sets--a gadoxetic acid set, including images from MR cholangiopancreatography, and a combined gadoxetic acid set and DW imaging set--to evaluate the tumor involvement of each biliary confluence and vascular and liver invasion by using receiver operating characteristic (ROC) curve analysis. RESULTS For each observer, area under the ROC curve (Az) values for tumor involvement of the biliary confluence were 0.965 and 0.957 for the gadoxetic acid set and 0.980 and 0.975 for the combined set, respectively (P > .05). For detecting 105 biliary confluences with tumor involvement, the sensitivities with the combined set (97.1% [102 of 105] and 98.1% [103 of 105]) were higher than those with the gadoxetic acid set (91.4% [96 of 105] for both observers) (P = .029 and P = .016), although the specificities were similar with both image sets (P > .05). For the detection of liver invasion, the combined set (75.0% [15 of 20] for both observers) yielded better sensitivity than the gadoxetic acid set (50.0% [10 of 20] and 45.0% [nine of 20]) (P = .016 and P = .031). For evaluation of vascular invasion, the two image sets showed similar diagnostic performance. CONCLUSION In the preoperative evaluation of hilar cholangiocarcinoma, the addition of DW imaging to gadoxetic acid-enhanced MR imaging could improve sensitivity in the evaluation of tumor extent along the bile duct and liver invasion.

Added value of diffusion-weighted MRI for evaluating viable tumor of hepatocellular carcinomas treated with radiotherapy in patients with chronic liver disease.

OBJECTIVE The purpose of this article is to evaluate the added value of diffusion-weighted imaging (DWI) to the diagnostic performance of conventional MRI in diagnosing viable hepatocellular carcinoma (HCC) tumors treated with radiotherapy in patients with chronic liver disease. MATERIALS AND METHODS Twenty-nine patients with viable tumor and 35 patients without viable tumor were enrolled. We assessed the signal intensity of viable tumor compared with irradiated liver on MRI and DWI. Signal intensity ratios and apparent diffusion coefficient (ADC) ratios of viable tumor to nonirradiated liver were also assessed on DWI with ADC maps. Two observers reviewed conventional MRI and combined MRI and DWI and rated them using a 5-point scale. Diagnostic performance was evaluated using a receiver operating characteristic (ROC) curve. RESULTS Viable tumors showed hyperintensity on T2-weighted and arterial phase images (16/29 [55.2%]) and hypointensity on portal (22/29 [75.9%]), 3-minute late (19/29 [65.5%]), and hepatobiliary phase (23/29 [79.3%]) images. Twenty-seven (93.1%) viable tumors showed hyperintensity on DWI and hypointensity on ADC maps. Mean signal intensity ratios and ADC ratios of viable tumor on DWI with ADC maps were significantly higher and lower than those of irradiated liver. Diagnostic performance (area under the ROC curve) improved significantly after adding DWI, and interobserver agreement was moderate for conventional MRI (κ = 0.450) and good after adding DWI (κ = 0.748). CONCLUSION Adding DWI to conventional MRI can improve the detection of viable HCC tumors treated with radiotherapy compared to conventional MRI alone.

Diagnostic Performance of Shear Wave Elastography for Predicting Esophageal Varices in Patients With Compensated Liver Cirrhosis

The purpose of this study was to investigate the diagnostic performance of shear wave elastography (SWE) for predicting the presence of esophageal varices and high‐risk esophageal varices in patients with compensated cirrhosis and to compare it with other nonspecific predictors and according to the presence of splenomegaly.

A novel electrode with electromagnetic tip tracking in ultrasonography-guided radiofrequency ablation: a phantom, ex vivo, and in vivo experimental study.

ObjectivesThe objective of this study was to compare the targeting and ablation performance between a newly developed radiofrequency (RF) electrode embedded with an electromagnetic position sensor (EMPS) at the electrode tip and a conventional RF electrode. Materials and MethodsThe institutional animal care and use committee approved this study. The targeting of paint balls within phantoms was performed under ultrasonography guidance by 2 radiologists (beginner vs expert) with an “in-plane” and “out-of-plane” approaches using the new RF electrode and a conventional RF electrode (n = 20 for each method). To evaluate the targeting performance, the electrode placement time and the number of electrode pullbacks for redirection were compared between the 2 electrodes. The ablation performance was also compared by analyzing the ablation volumes in ex vivo bovine and in vivo porcine livers (n = 30 and n = 24, respectively) and the cellular viability of the ablation zone in in vivo specimens. ResultsIn the phantom study, the RF electrode embedded with an EMPS showed a significantly shorter electrode placement time compared with the conventional RF electrode in both the in-plane and out-of-plane approaches by both radiologists (P < 0.05). The electrode pullback rate for both radiologists was lower in the new RF electrode than in the conventional RF electrode, but it did not reach statistical significance in the in-plane approach by the expert (P = 0.059). The ablation volumes analyzed with and without cellular viability in the ex vivo and in vivo studies were not significantly different between the 2 electrodes (P > 0.05). ConclusionsThe RF electrode embedded with an EMPS is faster than the conventional electrode in the electrode placement into the target lesions. The ablation performance is not significantly different between the 2 electrodes.

Comparison of therapeutic efficacy and safety of radiofrequency ablation of hepatocellular carcinomas between internally cooled 15-G and 17-G single electrodes

OBJECTIVE To compare the ablation volume, local tumour progression rate and complication rate of radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) using 15-G and 17-G single electrodes. METHODS This retrospective study was approved by the institutional review board and informed consent was waived. We reviewed percutaneous RFA cases for HCCs using 15-G or 17-G electrodes without multiple overlapping ablations. A total of 36 pairs of HCCs matched according to tumour size and active tip length were included. We compared ablation volume and complication rate between the two electrode groups. Cumulative local tumour progression rates were estimated using the Kaplan–Meier method and compared using the log-rank test. RESULTS Tumour size and ablation time were not significantly different between the 15-G and 17-G groups (p50.661 and p50.793, respectively). However, ablation volume in the 15-G electrode group was larger than that in the 17-G group (14.465.4cm3 vs 8.762.5cm3; p,0.001). No statistical difference in complication rates between the two electrode groups was found. The 10- and 20-month local tumour progression rates were not significantly different between the two groups (2.8% and 5.6% vs 11.1% and 19.3%; p50.166). CONCLUSION Ablation volume by the 15-G electrode was larger than that by the 17-G electrode. However, local tumour progression rate and complication rate were not significantly different between the two electrode groups. ADVANCES IN KNOWLEDGE RFA of HCC using a 15-G electrode is useful to create larger ablation volumes than a 17-G electrode.

How many times should we repeat measuring liver stiffness using shear wave elastography?: 5-repetition versus 10-repetition protocols

The purpose of this study is to evaluate whether a 5-repetition liver stiffness (LS) measurement as the standard protocol of shear wave elastography (SWE) is comparable to a conventional 10-repetition measurement protocol and to identify factors that influence the reliability of the 5-repetition protocol. A total of 346 patients (mean, 48.0years; range, 15-81years, M:F=192:154) who underwent SWE were enrolled. The median, first quartile, third quartile, and interquartile range divided by the median (IQR/M) of LS measurement were calculated and compared between 5-repetition and 10-repetition protocols. Subgroup analyses were also performed to identify factors associated with measurement reliability. The overall mean LS from the 10-repetition protocol was 7.97kPa, which was not significantly different from the mean LS of the 5-repetition protocol (7.91kPa; p=0.192). However, the third quartile and IQR/M values of the two groups were significantly different from each other (p=0.003 and <0.001). Subgroup analysis revealed that the 5-repetition results were significantly different from the 10-repetition results in the fatty liver and high LS subgroups. Therefore, the 5-repetition SWE measurement protocol can replace the conventional 10-repetition protocol, with the exception of patients with fatty liver disease or an LS value higher than 10kPa.