Seong Hyun Kim

Gastric cancer staging at isotropic MDCT including coronal and sagittal MPR images: endoscopically diagnosed early vs. advanced gastric cancer

BackgroundThe aims of this study are to evaluate and compare the accuracies of isotropic multi-detector row CT (MDCT) including multiplanar reconstruction (MPR) images for preoperative staging of endoscopically diagnosed early gastric cancer (eEGC) and advanced gastric cancer (eAGC).MethodsOne hundred and five patients with endoscopically proven gastric cancer underwent isotropic MDCT. Three independent radiologists evaluated T and N staging both on transverse images only and on three orthogonal MPR images. The staging of each tumor was surgico-pathologically confirmed. The receiver operating characteristic (ROC) analysis and the Wilcoxon signed ranked test were used for statistical analyses.ResultsIn 30 eAGCs, the accuracies for T and N staging with MPR imaging were better than those with transverse imaging (each Pxa0<xa00.05). In 34 eEGCs, however, only the accuracy of T2 or higher with MPR imaging was higher than that with transverse imaging (Pxa0<xa00.05).ConclusionsIsotropic MDCT with MPR images including coronal or sagittal reconstructions can improve the accuracies of preoperative T and N staging of eAGC, while having little impact on the accuracy for eEGC.

Needle tract implantation after percutaneous interventional procedures in hepatocellular carcinomas: lessons learned from a 10-year experience.

Percutaneous interventional procedures under image guidance, such as biopsy, ethanol injection therapy, and radiofrequency ablation play important roles in the management of hepatocellular carcinomas. Although uncommon, the procedures may result in tumor implantation along the needle tract, which is a major delayed complication. Implanted tumors usually appear as one or a few, round or oval-shaped, enhancing nodules along the needle tract on CT, from the intraperitoneum through the intercostal or abdominal muscles to the subcutaneous or cutaneous tissues. Radiologists should understand the mechanisms and risk factors of needle tract implantation, minimize this complication, and also pay attention to the presence of implanted tumors along the needle tract during follow-up.

Differentiating combined hepatocellular and cholangiocarcinoma from mass-forming intrahepatic cholangiocarcinoma using gadoxetic acid-enhanced MRI

To examine the differential features of combined hepatocellular and cholangiocarcinoma (HCC‐CC) from mass‐forming intrahepatic cholangiocarcinoma (ICC) on gadoxetic acid‐enhanced MRI.

Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced MRI versus Gadobenate Dimeglumine (Gd-BOPTA)-Enhanced MRI for Preoperatively Detecting Hepatocellular Carcinoma: an Initial Experience

Objective This study was designed to compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine-enhanced MRI for preoperatively detecting hepatocellular carcinoma (HCC). Materials and Methods Eighteen consecutive patients (17 men and one woman, age range: 31-73 years) with 22 HCCs underwent examinations with gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI on a 3.0-Tesla unit. The diagnosis of HCC was established after surgical resection and pathological conformation. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC was assessed by performing an alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated. Results The average value of the area under the ROC curve (Az) for gadoxetic acid enhanced MRI (0.887) was not significantly different from the Az (0.899) for gadobenate dimeglumine-enhanced MRI (p > 0.05). The overall sensitivities of gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI were 80% and 83%, respectively, with no significant difference (p > 0.05). The differences of the positive predictive values for the two contrast agents for each observer were not statistically significant (p > 0.05). Conclusion The diagnostic performance of gadoxetic acid-enhanced MRI and gadobenate dimeglumine-enhanced MRI for preoperatively detecting HCC is quite similar.

Assessment of triple-phase CT findings for the differentiation of fat-deficient hepatic angiomyolipoma from hepatocellular carcinoma in non-cirrhotic liver.

BACKGROUNDnTo evaluate the triple-phase CT findings for the differentiation of fat-deficient angiomyolipoma from hepatocellular carcinoma in non-cirrhotic liver.nnnMETHODSnWe retrospectively reviewed contrast-enhanced triple-phase CT images of 10 patients with fat-deficient hepatic angiomyolipoma and 28 patients with 29 hepatocellular carcinomas in non-cirrhotic liver proved on histologic examination. The CT findings for the two types of tumors were compared using Fishers exact test.nnnRESULTSnEarly draining vein depicted on arterial or portal phases was seen in eight (80%) angiomyolipomas and two hepatocellular carcinomas (7%) (p<0.001), in which the early draining vein was connected with tumoral vessels. The tumoral vessels in the angiomyolipoma were more prominent and ectatic, were distributed both centrally and peripherally, and were seen in smaller tumors than in the hepatocellular carcinoma. Tumor capsule enhancement was absent in all angiomyolipomas as compared with two (7%) hepatocellular carcinomas with no tumor capsule (p<0.001). The other CT findings were not significantly different for the two different types of tumors.nnnCONCLUSIONSnThe presence of early draining vein connecting with prominent tumoral vessels and absent tumor capsule were useful CT findings for the differentiation of fat-deficient angiomyolipoma from hepatocellular carcinoma in non-cirrhotic liver.

The value of gadoxetic acid-enhanced and diffusion-weighted MRI for prediction of grading of pancreatic neuroendocrine tumors.

Background Parenchyma-preserving resection for the treatment of benign pancreatic neuroendocrine tumors (NETs) has been tried, and preoperative prediction of benign pancreatic NET is important. Recently, diffusion-weighted imaging (DWI) of abdomen magnetic resonance imaging (MRI) has been used to characterize benign and malignant tumors and DWI might be helpful in prediction of benign pancreatic NETs. Purpose To evaluate the value of gadoxetic acid-enhanced MRI and DWI in predicting benign pancreatic NETs for determination of parenchyma-preserving resection. Material and Methods Our ethics committee approved this study with a waiver of informed consent given its retrospective design. We searched radiology and pathology databases from November 2010 to July 2012 to identify patients who underwent surgery for pancreatic NETs (<4u2009cm). Twenty patients in the benign group and 14 patients in the non-benign group were included in this study. Two radiologists analyzed the morphologic features, signal intensity on MR images including DWI (bu2009=u2009800), and dynamic enhancement pattern of the tumors with consensus. The tumor-to-parenchyma ratio and tumor apparent diffusion coefficients (ADCs) were quantitatively assessed. Results The benign pancreatic NETs were more often round (7/20, 35%) or ovoid (13/20, 65%) in shape and less hypovascular on the arterial phase (3/20, 15%) than were the non-benign pancreatic NETs (1/14, 7.1% and 5/14, 35.8%; 7/14, 50% respectively; Pu2009<u20090.05). Main pancreatic duct dilatation by tumors was demonstrated only in non-benign pancreatic NETs (4/14, 28.4%; Pu2009=u20090.021). ADC values and ratios were significantly different between benign pancreatic NETs (mean, 1.48u2009×u200910−3u2009mm2/sec, 1.11u2009±u20090.25, each) and non-benign pancreatic NETs (mean, 1.04u2009×u200910−3u2009mm2/sec, 0.74u2009±u20090.13, each) (Pu2009<u20090.01). Other qualitative and quantitative analyses between benign and non-benign pancreatic NETs were not significantly different (Pu2009>u20090.05). Conclusion Abdominal MRI with DWI may be useful for differentiating benign pancreatic NETs from non-benign pancreatic NETs, which might be helpful for determination of parenchyma-preserving resection.

Evaluation of esophageal varices on liver computed tomography: Receiver operating characteristic analyses of the performance of radiologists and endoscopists

Background and Aim:u2002 Recent liver multi‐detector row computed tomography (MDCT) always covers the distal esophagus with an excellent image quality. The aim of this study was to compare the performance of faculty abdominal radiologists with those of radiology residents and endoscopists for the detection of esophageal varices and high‐risk esophageal varices on liver MDCT.

Differentiating hepatic abscess from malignant mimickers: Value of diffusion‐weighted imaging with an emphasis on the periphery of the lesion

To evaluate the efficacy of diffusion‐weighted imaging (DWI) in differentiating hepatic abscess from malignant mimickers with an emphasis on periphery of the lesions.

Early diffuse recurrence of hepatocellular carcinoma after percutaneous radiofrequency ablation: analysis of risk factors

AbstractObjectiveTo evaluate the risk factors affecting early diffuse recurrence within 1xa0year of percutaneous ultrasound-guided radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).MethodsOut of 146 patients who received transcatheter arterial chemoembolisation (TACE) for treatment of recurrent HCC after percutaneous ultrasound-guided RFA, we selected 23 patients with early diffuse recurrence. Early diffuse recurrence was defined as three or more new recurrent HCCs within 1xa0year of initial RFA. As a control group, we selected 23 patients, matched exactly for age and sex, in which there was no local tumour progression or new recurrence after RFA. To analyse the risk factors, we examined patient factors and tumour factors.ResultsRecurrent tumours occurred from 30 to 365xa0days after RFA (median time, 203xa0days). Univariate analysis indicated that larger tumour size and poorly defined margin were significant risk factors (Pu2009<u20090.05). Multivariate analysis indicated that poorly defined margin was a significant risk factor (Pu2009<u20090.05).ConclusionLarger tumour size and poorly defined margin may be risk factors for early diffuse recurrence of HCC within 1xa0year of RFA. Tumours with such risk factors should be treated with a combination of TACE to minimise the potential for therapeutic failure.Key Points• Ultrasound-guided radiofrequency ablation (RFA) is widely used for hepatocellular carcinoma (HCC).n • Early diffuse recurrence after RFA is an important prognostic factorn • The risk factors for recurrence are larger tumour size and poorly defined marginsn • Tumours with such risk factors should be treated with transarterial chemoembolisation.

Gadoxetic acid-enhanced MRI versus multiphase multidetector row computed tomography for evaluating the viable tumor of hepatocellular carcinomas treated with image-guided tumor therapy

To compare the diagnostic performance of gadoxetic acid‐enhanced MRI with that of multi‐phase 40‐ or 64‐multidetector row computed tomography (MDCT) to evaluate viable tumors of hepatocellular carcinomas (HCCs) treated with image‐guided tumor therapy.