Feasibility of Simultaneous Multislice Acceleration Technique in Diffusion-Weighted Magnetic Resonance Imaging of the Rectum

OBJECTIVE: To assess the feasibility of simultaneous multislice-accelerated diffusion-weighted imaging (SMS-DWI) of the rectum in comparison with conventional DWI (C-DWI) in rectal cancer patients. MATERIALS AND METHODS: This study included 65 patients with initially-diagnosed rectal cancer. All patients underwent C-DWI and SMS-DWI with acceleration factors of 2 and 3 (SMS2-DWI and SMS3-DWI, respectively) using a 3T scanner. Acquisition times of the three DWI sequences were measured. Image quality in the three DWI sequences was reviewed by two independent radiologists using a 4-point Likert scale and subsequently compared using the Friedman test. Apparent diffusion coefficient (ADC) values for rectal cancer and the normal rectal wall were compared among the three sequences using repeated measures analysis of variance. RESULTS: Acquisition times using C-DWI, SMS2-DWI, and SMS3-DWI were 173 seconds, 107 seconds, (38.2% shorter than C-DWI), and 77 seconds (55.5% shorter than C-DWI), respectively. For all image quality parameters other than distortion (margin sharpness, artifact, lesion conspicuity, and overall image quality), C-DWI and SMS2-DWI yielded better results than did SMS3-DWI (Ps < 0.001), with no significant differences observed between C-DWI and SMS2-DWI (Ps ≥ 0.054). ADC values of rectal cancer (p = 0.943) and normal rectal wall (p = 0.360) were not significantly different among C-DWI, SMS2-DWI, and SMS3-DWI. CONCLUSION: SMS-DWI using an acceleration factor of 2 is feasible for rectal MRI resulting in substantial reductions in acquisition time while maintaining diagnostic image quality and similar ADC values to those of C-DWI.ope

Intraindividual Comparison between Gadoxetate-Enhanced Magnetic Resonance Imaging and Dynamic Computed Tomography for Characterizing Focal Hepatic Lesions: A Multicenter, Multireader Study

OBJECTIVE: To compare the diagnostic accuracy of dynamic computed tomography (CT) and gadoxetate-enhanced magnetic resonance imaging (MRI) for characterization of hepatic lesions by using the Liver Imaging Reporting and Data System (LI-RADS) in a multicenter, off-site evaluation. MATERIALS AND METHODS: In this retrospective multicenter study, we evaluated 231 hepatic lesions (114 hepatocellular carcinomas [HCCs], 58 non-HCC malignancies, and 59 benign lesions) confirmed histologically in 217 patients with chronic liver disease who underwent both gadoxetate-enhanced MRI and dynamic CT at one of five tertiary hospitals. Four radiologists at different institutes independently reviewed all MR images first and the CT images 4 weeks later. They evaluated the major and ancillary imaging features and categorized each hepatic lesion according to the LI-RADS v2014. Diagnostic performance was calculated and compared using generalized estimating equations. RESULTS: MRI showed higher sensitivity and accuracy than CT for diagnosing hepatic malignancies; the pooled sensitivities, specificities, and accuracies for categorizing LR-5/5V/M were 59.0% vs. 72.4% (CT vs. MRI; p < 0.001), 83.5% vs. 83.9% (p = 0.906), and 65.3% vs. 75.3% (p < 0.001), respectively. CT and MRI showed comparable capabilities for differentiating between HCC and other malignancies, with pooled accuracies of 79.9% and 82.4% for categorizing LR-M, respectively (p = 0.139). CONCLUSION: Gadoxetate-enhanced MRI showed superior accuracy for categorizing LR-5/5V/M in hepatic malignancies in comparison with dynamic CT. Both modalities had comparable accuracies for distinguishing other malignancies from HCC.ope

간세포암의 발견: 3테슬라 자기공명영상에서 확산강조영상, Gadoxetic Acid 조영증강영상, 두 영상 조합의 비교1

Purpose To compare diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced (Gdx) magnetic resonance imaging (MRI), whether alone or in combination, for the detection of hepatocellular carcinoma (HCC) by using 3 T. Materials and Methods 84 HCCs in 66 patients (57 men, 9 women; mean age 69.2 years) were examined using 3 T MRI. DWI (b values 0, 50, and 800 sec/mm2) and dynamic gadoxetic acid-enhanced MRI as well as hepatobiliary phase were performed. Images were retrospectively reviewed by two radiologists to compare the diagnostic performances of DWI and Gdx MRI alone and in combination for the detection of HCC. Alternative free response receiver operating characteristic analysis and comparison of sensitivities were used for statistical analysis. Results The sensitivity of Gdx set (73/84, 87%) was significantly higher than that of DWI set (60.5/84, 72%) for both observers. The Az values of DWI and Gdx MRI for the detection of HCC were not statistically significant for either observer (Az for DWI = 0.818 and 0.864, Az for Gdx MR = 0.902 and 0.842, respectively, p = 0.107 for observer 1 and p = 0.738 for observer 2). The combination of both techniques did not increase the sensitivities of detecting HCC in either observer. When lesions smaller than 2 cm were considered, the DWI set yielded a significantly lower sensitivity as compared with either the Gdx set alone or the combination set. Conclusion Gadoxetic acid-enhanced MRI was better than DWI for detection the HCC by using 3 T MRI. The combination of DWI and Gdx MRI did not contribute to the successful detection of HCC.ope

위절제술 후에 간의 제4분절에서 발생한 간전이를 닮은 국소 지방 침윤: 두 증례 보고

We present two cases of focal fat deposition developed at the posterior area of the segment IV in the liver, following gastrectomy in patients with gastric cancer. There was no focal lesion in this area of the liver at preoperative computed tomography (CT) in both cases, and the aberrant right gastric vein (ARGV) was found on the retrospective review of this CT. After gastrectomy, a focal, low-attenuating lesion was developed in this area on a follow-up CT in both cases, which was confirmed as a focal fat deposition, by other imaging studies. In addition to its typical imaging findings, confirmation of the presence of the ARGV also supported this lesion to be a focal fat deposition. Furthermore, understanding of our cases may be of help to prevent us from unnecessary invasive procedures, such as liver biopsy.ope

Benign focal liver lesions masquerading as primary liver cancers on MRI

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common primary liver malignancies. HCC and ICC have characteristic imaging findings, but a number of benign entities can appear similar and can cause diagnostic dilemma. Ideally, accurate and timely diagnosis of these conditions can help the patient to avoid a needle biopsy or even unnecessary treatment. In this article, we present various benign liver lesions that display imaging characteristics that are similar to HCC and ICC on magnetic resonance imaging (MRI) and discuss salient features that may assist in accurate diagnosis.ope

Consensus report from the 8th International Forum for Liver Magnetic Resonance Imaging

Objectives The 8th International Forum for Liver Magnetic Resonance Imaging (MRI), held in Basel, Switzerland, in October 2017, brought together clinical and academic radiologists from around the world to discuss developments in and reach consensus on key issues in the field of gadoxetic acid-enhanced liver MRI since the previous Forum held in 2013. Methods Two main themes in liver MRI were considered in detail at the Forum: the use of gadoxetic acid for contrast-enhanced MRI in patients with liver cirrhosis and the technical performance of gadoxetic acid-enhanced liver MRI, both opportunities and challenges. This article summarises the expert presentations and the delegate voting on consensus statements discussed at the Forum. Results and conclusions It was concluded that gadoxetic acid-enhanced MRI has higher sensitivity for the diagnosis of hepatocellular carcinoma (HCC), when compared with multidetector CT, by utilising features of hyperenhancement in the arterial phase and hypointensity in the hepatobiliary phase (HBP). Recent HCC management guidelines recognise an increasing role for gadoxetic acid-enhanced MRI in early diagnosis and monitoring post-resection. Additional research is needed to define the role of HBP in predicting microvascular invasion, to better define washout during the transitional phase in gadoxetic acid-enhanced MRI for HCC diagnosis, and to reduce the artefacts encountered in the arterial phase. Technical developments are being directed to shortening the MRI protocol for reducing time and patient discomfort and toward utilising faster imaging and non-Cartesian free-breathing approaches that have the potential to improve multiphasic dynamic imaging.ope

Intramural Hypoattenuated Nodules in Thickened Wall of the Gallbladder: CT Features According to Their Primary Causes

According to published reports, a common feature of xanthogranulomatous chole-cystitis is the presence of intramural hypoattenuated nodules in thickened gallbladderwall. These nodules can, however, also be seen in pathological conditions such as acute cholecystitis, hyperplastic cholecystoses (cholesterolosis and adenomyomatosis),gallbladder cancer, and other inflammatory diseases such as tuberculosis. Retrospective review of the abdominal CT findings in 622 patients who for various reasons underwent cholecystectomy during a one-year period showed that intramural nodules were present in 60. In this pictorial essay we illustrate the imaging features of the many different pathological conditions which give rise to intramural hypoattenuated nodules in thickened wall of the gallbladder, correlating these features with the histopathological findings.ope

Noninvasive Biomarker for Predicting Treatment Response to Concurrent Chemoradiotherapy in Patients with Hepatocellular Carcinoma

Purpose: To investigate noninvasive biomarkers for predicting treatment response in patients with locally advanced HCC who underwent concurrent chemoradiotherapy (CCRTx). Materials and Methods: Thirty patients (55.5 ± 10.2 years old, M:F = 24:6) who underwent CCRTx due to advanced HCC were enrolled. Contrast-enhanced US (CEUS) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) were obtained before and immediately after CCRTx. The third CEUS was obtained at one month after CCRTx was completed. Response was assessed at three months after CCRTx based on RECIST 1.1. Quantitative imaging biomarkers measured with CEUS and MRI were compared between groups. A cutoff value was calculated with ROC analysis. Overall survival (OS) was compared by the Breslow method. Results: Twenty-five patients were categorized into the non-progression group and five patients were categorized into the progression group. Peak enhancement of the first CEUS before CCRTx (PE1) was significantly lower in the non-progression group (median, 18.6%; IQR, 20.9%) than that in the progression group (median, 59.1%; IQR, 13.5%; P = 0.002). There was no significant difference in other quantitative biomarkers between the two groups. On ROC analysis, with a cutoff value of 42.6% in PE1, the non-progression group was diagnosed with a sensitivity of 90.9% and a specificity of 100%. OS was also significantly longer in patients with PE1 < 42.6% (P = 0.014). Conclusion: Early treatment response and OS could be predicted by PE on CEUS before CCRTx in patients with HCC.ope

2 Cases of Duodenal Papillary Cancer with Polypoid Protrusion: Findings of MRCP

Endoscopic retrograde cholangiopancreatography(ERCP) is the most useful method of diagnosis in duodenal papillary cancer. There are two morphological features in duodenal papillary cancer. Exophytic tumors can be diagnosed with the use of forceps or snare biopsies, and intra-papillary tumors can be detected by ERCP and confirmed by intraductal brush cytology. ERCP has diagnostic limitations when cannulation of the bile duct is not possible or when confirmation of duodenal papillary cancer is difficult in cases of normal duodenal mucosa. Although ERCP is generally considered a safe procedure, it has a morbidity and mortality of 7% and 1%, respectively. This is why a noninvasive method is needed in order to substitute the role of diagnostic ERCP. Magnetic resonance cholangiopancreatography (MRCP) is a relatively new imaging technique for the evaluation of the pancreaticobiliary tract. Projectional images, similar in appearance to ERCP, are obtained without administration of any oral or intravenous contrast agents. MRCP has a diagnostic accuracy comparable to that of ERCP for most of the pancreaticobiliary diseases, but duodenal papillary cancer remains a challenge for this imaging tool. Previous study on the diagnostic accuracy of MRCP in duodenal papillary cancer reported that it confirmed only 2 out of 6 cases, but recent technical advances have optimized the image. Therefore, further studies on the advanced quality is needed in the future. We report 2 cases of duodenal papillary cancer with polypoid protrusion correctly diagnosed as MRCP.ope

Pathological Analysis of 62 Liver Biopsy Cases with Hepatocellular Cholestasis : Drug andToxin Induced Liver Injury

Background: Hepatocellular cholestasis denotes the alteration of bile secretion by hepatocytes. The causes, degree of hepatocyte injury and concomitant bile duct loss are considered to influence the clinical course. Methods: The causes and pathological features of hepatocellular cholestasis were analyzed in 62 cases of liver biopsies; and the causes of primary biliary cirrhosis, primary sclerosing cholangitis, and biliary obstruction were not included. Results: The mean age of the patients was 42.2 years, and the ratio of male to female was 1.8:1. Fiftyeight cases (94%) showed cholestatic hepatitis, and 4 cases (6%) showed pure cholestasis without hepatitis activity. The majority of the cases (52 cases, 84%), including 19 cases of herbal medicine, was related to drugs. Loss of bile duct was found in 12 cases (19%), which were all cases of chronic cholestasis. All of them had drug histories, including 9 cases of herbal medicine. Clinical follow-up was performed in 9 out of the 12 cases with bile duct loss, and all of them showed elevated total bilirubin and/or alkaline phosphatase levels for more than 6 months. Conclusions: Drugs are the major cause of hepatocellular cholestatic hepatitis/cholestasis; and information about drugs, including herbal medicines, should be considered for proper evaluation of liver biopsy with hepatocellular cholestasis. Bile duct loss should be evaluated in the cases of chronic hepatocellular cholestasis, especially in drug induced cases.ope