Yong Moon Shin

Which Response Criteria Best Help Predict Survival of Patients with Hepatocellular Carcinoma Following Chemoembolization? A Validation Study of Old and New Models

PURPOSE To identify differences in radiologic assessment methods and determine optimal imaging criteria for response evaluation in hepatocellular carcinoma (HCC) patients treated with chemoembolization. MATERIALS AND METHODS Institutional review board approval was obtained, and patient informed consent was waived. The present study included 332 patients with intermediate stage HCC and Child-Pugh A cirrhosis who underwent serial chemoembolization. All measurable target lesions of 1 cm or larger in diameter were uni- and bidimensionally measured both at baseline and during follow-up. Intermodel agreement among the guidelines of the World Health Organization (WHO), Response Evaluation Criteria in Solid Tumors (RECIST), the European Association for the Study of the Liver (EASL), and modified RECIST (mRECIST) were examined. The most reliable model was selected on the basis of the correlation with survival prediction. RESULTS The κ values of comparisons among WHO, RECIST, and mRECIST guidelines were less than 0.20, whereas the κ value for the comparison of EASL and mRECIST guidelines was 0.94. In patients with a partial response (PR), stable disease (SD), or progressive disease (PD), compared with patients with a complete response (CR), hazard ratios (HRs) for survival were 2.99 (95% confidence interval [CI]: 2.14, 4.17), 3.49 (95% CI: 1.71, 7.10), and 15.63 (95% CI: 9.51, 25.69), respectively, for EASL criteria. In patients with a PR, SD, or PD, compared with patients with a CR, the HRs were 2.75 (95% CI: 1.96, 3.87), 6.32 (95% CI: 3.67, 10.90), and 16.06 (95% CI: 9.76, 26.43), respectively, for mRECIST guidelines (P<.001). The C index for the multivariate model was 0.76 (95% CI: 0.72, 0.79) for both EASL and mRECIST guidelines, thus exhibiting satisfactory capability to help predict survival. The Cox regression model revealed that both mRECIST and EASL guidelines were independent predictors of overall survival (P<.001 for both). CONCLUSION The enhancement models more accurately helped predict long-term survival in HCC patients treated with chemoembolization.

Radiofrequency Ablation for the Treatment of Primary Intrahepatic Cholangiocarcinoma

OBJECTIVE We present the results of percutaneous radiofrequency ablation (RFA) in patients with unresectable primary intrahepatic cholangiocarcinoma. MATERIALS AND METHODS From 2000 to 2009, 13 patients with 17 primary intrahepatic cholangiocarcinomas underwent RFA at our institution. Intrahepatic cholangiocarcinoma was unresectable because of poor hepatic reserve due to liver cirrhosis in nine patients, extrahepatic extension in two, atrophy of the left hepatic lobe in one, and underlying comorbidities in one. Ten tumors had a diameter of less than 3 cm, five were between 3 and 5 cm, and two were larger than 5 cm. Technical effectiveness was defined as the complete ablation of the tumor, shown by imaging follow-up 1 month later. Local progression-free survival, overall survival periods, and complications after RFA were also evaluated. RESULTS Technical effectiveness of RFA was achieved for 15 of the 17 tumors (88%), all smaller than 5 cm in diameter. Treatment failure occurred in two patients with large tumors (7 and 8 cm). After the 17 RFA sessions, one major complication (6%), a liver abscess, occurred 1 month later. During follow-up (median, 19.5 months; range, 3.3-82.1 months), nine patients died and four remain alive. Median local progression-free survival and overall survival periods were 32.2 and 38.5 months, respectively. The 1-, 3-, and 5-year survival rates were 85%, 51%, and 15%, respectively. CONCLUSION RFA may provide successful local tumor control in patients with primary intrahepatic cholangiocarcinomas of intermediate (3-5 cm) or small (< 3 cm) diameter. RFA for unresectable primary intrahepatic cholangiocarcinoma resulted in a median overall survival period of 38.5 months.

Efficient liver segmentation using a level-set method with optimal detection of the initial liver boundary from level-set speed images

Automatic liver segmentation is difficult because of the wide range of human variations in the shapes of the liver. In addition, nearby organs and tissues have similar intensity distributions to the liver, making the livers boundaries ambiguous. In this study, we propose a fast and accurate liver segmentation method from contrast-enhanced computed tomography (CT) images. We apply the two-step seeded region growing (SRG) onto level-set speed images to define an approximate initial liver boundary. The first SRG efficiently divides a CT image into a set of discrete objects based on the gradient information and connectivity. The second SRG detects the objects belonging to the liver based on a 2.5-dimensional shape propagation, which models the segmented liver boundary of the slice immediately above or below the current slice by points being narrow-band, or local maxima of distance from the boundary. With such optimal estimation of the initial liver boundary, our method decreases the computation time by minimizing level-set propagation, which converges at the optimal position within a fixed iteration number. We utilize level-set speed images that have been generally used for level-set propagation to detect the initial liver boundary with the additional help of computationally inexpensive steps, which improves computational efficiency. Finally, a rolling ball algorithm is applied to refine the liver boundary more accurately. Our method was validated on 20 sets of abdominal CT scans and the results were compared with the manually segmented result. The average absolute volume error was 1.25+/-0.70%. The average processing time for segmenting one slice was 3.35 s, which is over 15 times faster than manual segmentation or the previously proposed technique. Our method could be used for liver transplantation planning, which requires a fast and accurate measurement of liver volume.

Focal Fatty Replacement of the Pancreas: Usefulness of Chemical Shift MRI

OBJECTIVE The purpose of this study was to describe the typical CT and chemical shift MRI findings and to evaluate their usefulness in the diagnosis of focal fatty replacement of the pancreas in five patients. CONCLUSION The presence of a perceptible focal low-attenuation lesion in the pancreas on CT and the reduction in signal intensity of the lesion on the opposed phase of chemical shift MR images are useful for differentiating focal fatty replacement of the pancreas from true pancreatic neoplasm. Therefore, these imaging findings obviate invasive diagnostic procedures and surgery in the care of patients with focal fatty replacement of the pancreas.

Sorafenib Alone versus Sorafenib Combined with Transarterial Chemoembolization for Advanced-Stage Hepatocellular Carcinoma: Results of Propensity Score Analyses

PURPOSE To compare the time to progression (TTP) and overall survival (OS) in patients with advanced-stage hepatocellular carcinoma (HCC) who are undergoing sorafenib treatment combined with transarterial chemoembolization (TACE) versus sorafenib monotherapy. MATERIALS AND METHODS The retrospective analysis of the data was approved by the institutional review board, and the requirement to obtain informed consent was waived. Of 355 patients with advanced-stage HCC (Barcelona Clinic Liver Cancer stage C) who were undergoing sorafenib therapy for at least 5 weeks between April 2007 and July 2011, 164 (46.2%) underwent repeat TACE (or chemolipiodolization if indicated) along with sorafenib therapy (combined group); the remaining 191 patients (53.8%) received sorafenib alone (monotherapy group). The median patient age was 53 years (range, 22-84 years). The median age was 53 years (range, 26-84 years) for men and 56 years (range, 22-75 years) for women. Propensity score-based methods were used to minimize bias when evaluating TTP on the basis of modified Response Evaluation Criteria in Solid Tumors and OS. Statistical analysis was performed with the Kaplan-Meier method by using the log-rank test and Cox regression models. RESULTS In the combined and monotherapy groups, respectively, 64.6% and 49.2% of patients had vascular invasion, 87.8% and 91.1% had extrahepatic metastasis, and 54.3% and 47.1% had both. During follow-up (median duration, 5.5 months), the median TTP and OS in the combined group were longer than those in the monotherapy group (TTP: 2.5 months vs 2.1 months, respectively, P = .008; OS: 8.9 months vs 5.9 months, P = .009). At univariate and subsequent multivariate analyses, additional TACE was an independent predictor of favorable TTP and OS (adjusted hazard ratio: 0.74 and 0.57, respectively; P < .05 for both), consistent with the outcomes of inverse probability of treatment weighting. In the propensity score-matched cohort (96 pairs), the median TTP in the combined group was significantly longer than that in the monotherapy group (2.7 months vs 2.1 months, respectively; P = .011), but median OS was not (9.1 months vs 6.7 months, P = .21). CONCLUSION In this retrospective study, TACE plus sorafenib was superior to sorafenib alone with respect to TTP in patients with advanced-stage HCC, although it may or may not improve OS. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13130150/-/DC1.

Flat Polyps of the Colon: Detection with 16-MDCT Colonography—Preliminary Results

OBJECTIVE This study evaluates the ability of contrast-enhanced, 16-MDCT colonography to display flat colonic lesions when a very narrow slice thickness (1 mm) is used. CONCLUSION Less than 50% of flat lesions in our population could be visualized by blinded and unblinded review. Before they could be visualized, flat lesions were 2 mm or greater in height and 7 mm or greater in diameter. Lesions with a height of 1 mm or less were not seen on CT colonography. Contrast enhancement, location on a haustral fold, and abnormal 2D and 3D morphology contributed to lesion conspicuity.

Image quality and focal lesion detection on T2‐weighted MR imaging of the liver: Comparison of two high‐resolution free‐breathing imaging techniques with two breath‐hold imaging techniques

To evaluate image quality and accuracy for the detection of focal hepatic lesions depicted on T2‐weighted images obtained with two high‐resolution free‐breathing techniques (navigator‐triggered turbo spin‐echo [TSE] and respiratory‐triggered TSE) and two standard‐resolution breath‐hold techniques (breath‐hold TSE with restore pulse and half‐Fourier acquisition single‐shot TSE [HASTE]).

CT-guided Radiofrequency Ablation for Hepatocellular Carcinomas That Were Undetectable at US: Therapeutic Effectiveness and Safety

PURPOSE To determine the therapeutic effectiveness and safety of computed tomography (CT)-guided radiofrequency (RF) ablation for hepatocelluar carcinomas (HCCs) that were undetectable at ultrasonography (US). MATERIALS AND METHODS CT-guided RF ablation with use of internally cooled electrodes was performed in 66 patients with 97 HCCs (diameter range, 3-39 mm) in 78 sessions. Two radiologists retrospectively evaluated in consensus the presence or absence of local tumor progression as well as the complications at CT performed immediately after RF ablation and at 1-, 3-, 6-, and 12-month follow-up. The relationship between the occurrence of pneumothorax and the electrode length in the lung in patients treated with the transpulmonary approach was statistically evaluated with use of the Mann-Whitney test. RESULTS The technical success rate of CT-guided RF ablation immediately after RF ablation was 97% (94 of 97 HCCs). The primary technique effectiveness rates of complete ablation 1, 3, 6, and 12 months after RF ablation were 97% (94 of 97 HCCs), 94% (91 of 97 HCCs), 84% (81 of 96 HCCs), and 74% (66 of 89 HCCs), respectively. Major complications were observed in six of the 78 treatment sessions (7.7%). In five of these six sessions, pneumothorax developed immediately after RF ablation; the remaining complication was tumor seeding along the electrode tract. Self-limiting pneumothorax was observed in 12 of 38 sessions (32%) in which the transpulmonary approach was used. The electrode length in the lung was not statistically related to the occurrence of pneumothorax (P = .26). CONCLUSIONS For HCCs that are undetectable at US, CT-guided RF ablation is effective and relatively safe.

Gastric schwannomas: radiological features with endoscopic and pathological correlation

AIM To describe the radiological, endoscopic, and pathological findings of gastric schwannomas in 16 patients. MATERIALS AND METHODS The radiological, endoscopic, and pathological findings of 16 surgically proven cases of gastric schwannoma were retrospectively reviewed. All patients underwent computed tomography (CT) and four patients were evaluated with upper gastrointestinal series. Two radiologists reviewed the CT and upper gastrointestinal series images by consensus with regard to tumour size, contour, margin, and growth pattern, the presence or absence of ulcer, cystic change, and the CT enhancement pattern. Endoscopy was performed in eight of these 16 patients. Six patients underwent endoscopic ultrasonography. Pathological specimens were obtained from and reviewed in all 16 patients. Immunohistochemistry was performed for c-kit, CD34, smooth muscle actin, and S-100 protein. RESULTS On radiographic examination, gastric schwannomas appeared as submucosal tumours with the CT features of well-demarcated, homogeneous, and uncommonly ulcerated masses. Endoscopy with endoscopic ultrasonography demonstrated homogeneous, submucosal masses contiguous with the muscularis propria in all six examined cases. On pathological examination, gastric schwannomas appeared as well-circumscribed and homogeneous tumours in the muscularis propria and consisted microscopically of interlacing bundles of spindle cells. Strong positivity for S-100 protein was demonstrated in all 16 cases on immunohistochemistry. CONCLUSION Gastric schwannomas appear as submucosal tumours of the stomach and have well-demarcated and homogeneous features on CT, endoscopic ultrasonography, and gross pathology. Immunohistochemistry consistently reveals positivity for S-100 protein in the tumours.

Biopsy-proven Nonsteatotic Liver in Adults: Estimation of Reference Range for Difference in Attenuation between the Liver and the Spleen at Nonenhanced CT

PURPOSE To establish the reference range for hepatic attenuation minus splenic attenuation difference (CT(L-S)) values on nonenhanced computed tomographic (CT) images obtained in adults with a biopsy-proved nonsteatotic liver and determine the CT(L-S) criterion for diagnosing hepatic steatosis. MATERIALS AND METHODS This retrospective study was institutional review board approved, and all subjects had provided written informed consent. The CT(L-S) was measured in 315 liver donor candidates (207 men, 108 women; mean age, 31.5 years ± 10.1 [standard deviation]) who underwent nonenhanced CT of the liver and subsequent ultrasonographically guided liver biopsy on the same day. Nonenhanced liver CT was performed with a 16-section multidetector scanner in 154 individuals and with a 64-section multidetector scanner in 161 individuals. Biopsy specimens were analyzed for degree of hepatic steatosis and iron deposition. The CT(L-S) reference range was determined according to Clinical and Laboratory Standards Institute guideline C28-A3 in individuals with a histologically proved nonsteatotic liver. The sensitivity of nonenhanced CT for the diagnosis of 5% or greater and 30% or greater hepatic steatosis with use of the lower limit of the reference range as the diagnostic cutoff was determined. The effects of subject age and sex, CT scanner type, and hepatic iron on the CT(L-S) were evaluated by using multiple linear regression analysis. RESULTS Ninety-six subjects (48 men, 48 women) were found to have a histologically proved nonsteatotic liver, with an estimated reference range for CT(L-S) values of 1-18 HU. With a CT(L-S) of less than 1 HU as the criterion for hepatic steatosis, the sensitivities of nonenhanced CT for 5% or greater and 30% or greater hepatic steatosis were 18.6% (29 of 156 subjects) and 67% (26 of 39 subjects), respectively. Subject age had a significant but negligible effect on CT(L-S) (0.076-HU increase per year of age, P = .009), subject sex and scanner type had no effects on CT(L-S), and hepatic iron deposition significantly increased the CT(L-S) (1.434-HU increase per increase in iron deposition grade, P = .011). CONCLUSION The histologically proved reference range of CT(L-S) values for nonsteatotic livers was 1-18 HU. A CT(L-S) of less than 1 HU could be used as a conservative criterion for diagnosing hepatic steatosis with nonenhanced CT more consistently.