[Burnout among Radiologists in Korea: Prevalence, Risk Factors, and Remedies]. / 한국 영상의학과 의사의 탈진: 빈도, 위험인자, 해결 방안.

Burnout among radiologists has recently emerged as an issue that poses a threat to patient safety. Burnout adversely effects the quality of patient care and may lead to health problems in physicians. Approximately 84% of board-certified radiologists working in large hospitals in Korea responded that they had experienced burnout at least once. To overcome this, the standardization of physicians' workloads, as well as improvements in the professional workflow are necessary to ensure a healthy lifestyle balance.

Multiparametric US for Identifying Patients with High-Risk NASH: A Derivation and Validation Study.

Background Nonalcoholic fatty liver disease (NAFLD) is common in the general population but identifying patients with high-risk nonalcoholic steatohepatitis (NASH) who are candidates for pharmacologic therapy remains a challenge. Purpose To develop a score to identify patients with high-risk NASH, defined as NASH with an NAFLD activity score (NAS) of 4 or greater and clinically significant fibrosis (stage 2 [F2] or higher). Materials and Methods This was a cross-sectional secondary analysis of data prospectively collected between April 2017 and March 2019 for a group of patients with NAFLD in Japan (Japan NAFLD, the derivation data set) with contemporaneous two-dimensional shear-wave elastography and biopsy-proven NAFLD (age range, 20-89 years). Three US markers (liver stiffness [LS, measured in kilopascals], attenuation coefficient [AC, measured in decibels per centimeter per megahertz], and dispersion slope [DS, measured in meters per second per kilohertz]) were determined, together with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the AST-to-ALT ratio. The best-fit multivariate logistic regression model for identifying patients with high-risk NASH was determined. Diagnostic performance was assessed by using the area under the receiver operating characteristic curve (AUC). The findings were validated in an independent data set (Korea NAFLD; age range, 20-78 years). Results The Japan NAFLD data set included 111 patients (mean age, 53 years ± 18 [standard deviation]; 57 men), 84 (76%) with NASH. The Korea NAFLD data set included 102 patients (mean age, 48 years ± 18; 43 men), 55 (36%) with NASH. The most predictive model (LAD NASH score) combined LS, AC, and DS. Performance was satisfactory in both the derivation sample (AUC, 0.86; 95% CI: 0.79, 0.93) and the validation sample (AUC, 0.88; 95% CI: 0.80, 0.95). The LAD NASH score showed a positive predictive value of 86.5% and a negative predictive value of 87.5% for high-risk NASH in the derivation sample. Conclusion A score combining three US markers may be useful for noninvasive identification of patients with high-risk nonalcoholic steatohepatitis for inclusion in clinical trials and pharmacologic therapy. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lockhart in this issue.

Severity of hyperechoic pancreas on ultrasonography as a risk factor for glycemic progression.

PURPOSE: The aim of this study was to evaluate the association between the severity of hyperechoic pancreas (HP) on ultrasonography (US) and glycemic progression. METHODS: In total, 1,386 participants who underwent abdominal US as part of health examinations between December 2008 and May 2014 were included in this retrospective study. We classified pancreatic echogenicity on a 4-point scale, and compared it using two distinct criteria: fatty pancreas (FP) 1 criterion (normal vs. ≥mild HP) and FP2 criterion (normal/mild HP vs. ≥moderate HP). According to the presence of nonalcoholic fatty liver disease (NAFLD), participants were subdivided into four groups: non-NAFLD and non-HP, isolated NAFLD, isolated HP, and HP with NAFLD. Glycemic progression was defined as progression from normoglycemia to prediabetes or diabetes or progression from prediabetes to diabetes. RESULTS: During the follow-up (median, 5.9 years), 262 of the 1,386 participants developed glycemic progression. Using FP2, the probability of glycemic progression across the four subgroups showed cumulative aggravation for NAFLD and HP (all P<0.05). Isolated HP showed a higher probability of glycemic progression than isolated NAFLD according to FP2 (P<0.001). The highest probability of glycemic progression was observed in patients with both NAFLD and HP (P<0.001). The hazard ratio for glycemic progression increased with the severity of HP. CONCLUSION: Increasing severity of HP on US was found to be significantly correlated with glycemic progression. Moreover, isolated HP of moderate or greater severity predicted glycemic progression independent of NAFLD.

Detection of Ureteral Stones in Kidney Ureter Bladder Radiography: Usefulness of Digital Post-processing.

PURPOSE: Kidney, Ureter, and Bladder radiography (KUB) has frequently been used in suspected urolithiasis, but its performance is known to be lower than that of Computed Tomography (CT). This study aimed to investigate the diagnostic performance of digitally KUB in the detection of ureteral stones. MATERIALS AND METHODS: Thirty patients who underwent digital KUB and CT were included in this retrospective study. The original digital KUB underwent post-processing that involved noise estimation, reduction, and whitening in improving the visibility of ureteral stones. Thus, 60 digital original or post-processed KUB images were obtained and ordered randomly for blinded review. After a period, a second review was performed after unblinding stone laterality. The detection rates were evaluated at both initial and second reviews, using CT as a reference standard. The objective (size) and subjective (visibility) parameters of ureteral stones were analyzed. Fisher's exact test was used to compare the detection sensitivity between the original and post-processed KUB data set. Visibility analysis was assessed with a paired t-test. The correlation of stone size between CT and digital KUB data sets was assessed with the Pearson's correlation test. RESULTS: The detection rate was higher for most reviewers once stone laterality was provided and was non-significantly better for the post-processed KUB images (p > 0.05). There was no significant difference in stone size among CT and digital KUB data sets. In all reviews, visibility grade was higher in the post-processed KUB images, irrespective of whether stone laterality was provided. CONCLUSION: Digital post-processing of KUB yielded higher visibility of ureteral stones and could improve stone detection, especially when stone laterality was available. Thus, digitally post-processed KUB can be an excellent modality for detecting ureteral stones and measuring their exact size.

Ultrasonographic features of uterine cervical lesions.

Currently, ultrasound (US) is a valuable imaging tool for the initial assessment and evaluation of the female genital organs, uterus, and adnexa. However, it is easy to overlook the uterine cervix while conducting a pelvic US. Uterine cervical lesions may range from benign to malignant in nature. Therefore, meticulous examination with US may play a key role in assessing uterine cervical lesions. Although there is substantial overlap in the US findings across various uterine cervical lesions, some US features, in tandem with clinical characteristics, may suggest a specific diagnosis. Familiarity with the clinical settings and US characteristics of different uterine cervical lesions can support prompt and accurate diagnosis of suspicious lesions. This review article aims to describe the features of US and possible values for distinction of these lesions in the uterine cervix.

2D shear wave elastography is better than transient elastography in predicting post-hepatectomy complication after resection.

OBJECTIVES: Both transient elastography (TE) and 2D shear wave elastography (SWE) are accurate methods to evaluate liver fibrosis. We aimed to evaluate the diagnostic performance of 2D-SWE in predicting post-hepatectomy complication and to compare it with TE. METHODS: We prospectively enrolled 125 patients with liver tumors. Liver stiffness (LS) (kilopascal [kPa]) was measured using both TE and 2D-SWE before surgery. All post-operative complication was evaluated using the comprehensive complication index (CCI), and CCI ≥ 26.2 was defined as severe complication. Logistic regression analysis was performed to identify predictive factors for severe complication. Receiver operating characteristic analysis was used to evaluate the diagnostic performance of TE/2D-SWE in detecting liver fibrosis and severe complication. RESULTS: Severe complication developed in 18 patients. The median LS in patients with severe complication was significantly higher for both 2D-SWE (11.4 kPa vs. 7.0 kPa, p < 0.001) and TE (8.9 kPa vs. 6.2 kPa, p = 0.009). LS obtained from 2D-SWE was a significant factor correlated with severe complication (odds ratio: 1.27 per kPa [1.10-1.46], p = 0.001). The diagnostic performance of 2D-SWE was significantly higher than that of TE in detecting both ≥F3 (p = 0.024) and F4 (p = 0.048). The area under the curve of 2D-SWE to predict severe complication was 0.854, significantly higher than 0.692 of TE (p = 0.004). The optimal cut-off LS from 2D-SWE to predict severe complication was 8.6 kPa, with sensitivity of 88.9% (16/18) and specificity of 73.8% (79/107). CONCLUSION: LS obtained from 2D-SWE was a significant predictive factor for severe complication, and 2D-SWE showed significantly a better diagnostic performance than TE in detecting liver fibrosis and severe complication. KEY POINTS: • The diagnostic performance of 2D-SWE was significantly higher than that of TE in detecting both ≥ F3 (AUC: 0.853 vs. 0.779, p = 0.024) and F4 (AUC: 0.929 vs. 0.872, p = 0.048). • Liver stiffness value obtained from 2D-SWE was a significant factor correlated with the development of severe complication defined as CCI ≥ 26.2 after hepatic resection for liver tumors (odds ratio: 1.27 per kPa [1.10-1.46], p = 0.001). • 2D-SWE provided significantly a better diagnostic performance in predicting severe complication after hepatic resection than TE (AUC for 2D-SWE: 0.853 vs. AUC for TE: 0.692, p = 0.004).

Accuracy of Two-Dimensional Shear Wave Elastography and Attenuation Imaging for Evaluation of Patients With Nonalcoholic Steatohepatitis.

BACKGROUND & AIMS: We evaluated the accuracy of a multiparametric approach using attenuation imaging and 2-dimensional shear wave elastography (2D-SWE) for the detection of steatosis and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). METHODS: We studied 102 patients with increased levels of liver enzymes or suspicion of NAFLD, examined by attenuation imaging and 2D-SWE, immediately before biopsy collection and analysis (reference standard), from January 2018 to July 2019. We collected data on the attenuation coefficient (dB/cm/MHz) from attenuation imaging, liver stiffness measurements, and shear wave dispersion slope (SWDS, [m/s]/kHz) from 2D-SWE. Multivariate linear regression analysis was performed to identify factors associated with each parameter. Diagnostic performance was determined from area under the receiver operating curve (AUROC) values. RESULTS: The attenuation coefficient was associated with steatosis grade (P < .01) and identified patients with steatosis grades S1 or higher, S2 or higher, and S3 or higher, with AUROC values of 0.93, 0.88, and 0.83, respectively. Liver stiffness associated with fibrosis stage (P < .01) and lobular inflammatory activity was the only factor associated with SWDS (P < .01). SWDS detected inflammation grades I1 or higher, I2 or higher, and I3 or higher with AUROC values of 0.89, 0.85, and 0.78, respectively. We developed a risk scoring system to detect steatohepatitis based on the attenuation coefficient (score of 1 for 0.64 < attenuation coefficient ≤ 0.70; score of 2 for 0.70 < attenuation coefficient ≤ 0.73; and score of 3 for attenuation coefficient >0.73) and SWDS (score of 2 for 10.5 [m/s]/kHz < SWDS ≤ 11.7 [m/s]/kHz; and score of 3 for SWDS >11.7 [m/s]/kHz), using an unweighted sum of each score. Based on histopathology analysis, 55 patients had steatohepatitis. Risk scores correlated with NAFLD activity score (rho = 0.73; P < .01). Our scoring system identified patients with steatohepatitis with an AUROC of 0.93-this value was significantly higher than that of other parameters (P < .05), except SWDS (AUROC, 0.89; P = .18). CONCLUSIONS: In the evaluation of patients with suspected NAFLD, the attenuation coefficient can identify patients with steatosis and liver stiffness can detect fibrosis accurately. SWDS was associated significantly with lobular inflammation. We developed a risk scoring system based on the attenuation coefficient and SWDS that might be used to detect steatohepatitis.

Quantitative Assessment of Fatty Liver using Ultrasound with Normalized Local Variance Technique.

PURPOSE: To assess the diagnostic performance of the normalized local variance (NLV) ultrasound technique in the detection of the fatty liver using histopathology as a reference standard. MATERIALS AND METHODS: We prospectively enrolled 194 consecutive patients with clinical suspicion of diffuse liver disease or history of liver transplantation. Conventional grayscale ultrasound and NLV examinations were performed and immediately followed by liver biopsies. The degrees of fatty liver, necroinflammatory activity, and fibrosis stage were evaluated by histopathological assessment. The diagnostic performance of the NLV values in detecting each grade of fatty liver was determined using receiver operating characteristics analyses, and multivariate linear regression analyses were performed to identify variables significantly associated with the NLV values. RESULTS: The number of patients in each degree of fatty liver and hepatic fibrosis was 118/37/26/13 and 81/68/24/6/14 for none/mild/moderate/severe steatosis and F0 / F1/F2 / F3/F4 fibrosis on histopathological examinations, respectively. The area under the receiver operating characteristics curve and optimal cut-off NLV value for detecting fatty liver of varying degrees were 0.911 and 1.095 for ≥ S1, 0.974 and 1.055 for ≥ S2, and 0.954 and 1.025 for ≥ S3, respectively. Multivariate analyses revealed that not fibrosis or inflammation but rather the degree of steatosis was associated with the NLV value. CONCLUSION: The NLV value demonstrated excellent diagnostic performance for detecting varying degrees of fatty liver, and the degree of steatosis on histopathological examinations was the only significant factor affecting the NLV value.

Added value of 2D shear wave imaging of the gallbladder bed of the liver for acute cholecystitis.

PURPOSE: The purpose of this study was to evaluate whether shear wave elastography (SWE) and the shear wave dispersion slope (SWD) obtained from 2-dimensional shear wave imaging (2D-SWI) of the gallbladder (GB) bed of the liver could be helpful in the diagnosis of acute cholecystitis. METHODS: We included 44 patients referred for abdominal ultrasonography (US) under the impression of acute cholecystitis from April 2018 to March 2019. Patients with chronic liver disease were excluded from this study. In addition to routine upper abdominal US, we performed 2D-SWI including liver stiffness measurements by SWE and SWD, which reflects tissue viscosity. 2D-SWI was performed at the GB bed of the liver through the right intercostal approach at least 3 times with different frames. We assessed typical US findings and the added value of 2D-SWI in diagnosing acute cholecystitis. Histopathologic results of surgical specimens were used as the standard of reference. If a surgical specimen was unavailable, a bile fluid test or clinical follow-up for more than 3 months served as the reference standard. RESULTS: The optimal cutoff values for SWE and SWD were 8 kPa and 10.9 (m/sec)/kHz, respectively. In the univariate analysis, SWE, GB distension, and sludge were predictive factors of acute cholecystitis. In the multivariate analysis, categorized SWE was the only significant predictor (P<0.01). By using 2D-SWI, the diagnostic performance of two readers did not significantly increase, although the inter-reader agreement improved (k=0.654-0.778). CONCLUSION: 2D-SWI of the GB bed of the liver could be helpful for diagnosing acute cholecystitis.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid.

The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

Two-Dimensional-Shear Wave Elastography with a Propagation Map: Prospective Evaluation of Liver Fibrosis Using Histopathology as the Reference Standard.

OBJECTIVE: The aim of this study was to prospectively evaluate whether liver stiffness (LS) assessments, obtained by two-dimensional (2D)-shear wave elastography (SWE) with a propagation map, can evaluate liver fibrosis stage using histopathology as the reference standard. MATERIALS AND METHODS: We prospectively enrolled 123 patients who had undergone percutaneous liver biopsy from two tertiary referral hospitals. All patients underwent 2D-SWE examination prior to biopsy, and LS values (kilopascal [kPa]) were obtained. On histopathologic examination, fibrosis stage (F0-F4) and necroinflammatory activity grade (A0-A4) were assessed. Multivariate linear regression analysis was performed to determine the significant factors affecting the LS value. The diagnostic performance of the LS value for staging fibrosis was assessed using receiver operating characteristic (ROC) analysis, and the optimal cut-off value was determined by the Youden index. RESULTS: Reliable measurements of LS values were obtained in 114 patients (92.7%, 114/123). LS values obtained from 2D-SWE with the propagation map positively correlated with the progression of liver fibrosis reported from histopathology (p < 0.001). According to the multivariate linear regression analysis, fibrosis stage was the only factor significantly associated with LS (p < 0.001). The area under the ROC curve of LS from 2D-SWE with the propagation map was 0.773, 0.865, 0.946, and 0.950 for detecting F ≥ 1, F ≥ 2, F ≥ 3, and F = 4, respectively. The optimal cut-off LS values were 5.4, 7.8, 9.4, and 12.2 kPa for F ≥ 1, F ≥ 2, F ≥ 3, and F = 4, respectively. The corresponding sensitivity and specificity of the LS value for detecting cirrhosis were 90.9% and 88.4%, respectively. CONCLUSION: The LS value obtained from 2D-SWE with a propagation map provides excellent diagnostic performance in evaluating liver fibrosis stage, determined by histopathology.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS.

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

Guidelines and Good Clinical Practice Recommendations for Contrast-Enhanced Ultrasound (CEUS) in the Liver-Update 2020 WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS.

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid.

The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

History of the Asian Society of Abdominal Radiology.

The history and administrative system of the Asian Society of Abdominal Radiology (ASAR) are described briefly with a focus on its academic activity, including congresses and education. ASAR is one of the three regional societies in the field of abdominal radiology, comprising approximately 2500 members from seven countries in Asia. A further increase in the numbers of members and affiliated societies is expected with the advancement of imaging technology and the distribution of radiologic equipment and knowledge. ASAR is responsible in Asia for matters of interdisciplinary collaboration in the field of abdominal radiology and has successfully represented Asia in the field of radiology.

Imaging Features of Extramammary Paget Disease of the Scrotum: A Case Report.

Extramammary Paget disease (EMPD) is a rare intraepithelial malignancy originating in areas rich in apocrine glands, such as the vulva, perineum, perianal area, scrotum, and penis. A few reports of EMPD involving the scrotum have been described in the literature. However, only few reports have described imaging features observed in patients presenting with EMPD. We report EMPD in a patient showing scrotal involvement, focusing on imaging features, particularly those determined ultrasonographically.

Technical success rates and reliability of spin-echo echo-planar imaging (SE-EPI) MR elastography in patients with chronic liver disease or liver cirrhosis.

OBJECTIVES: To determine the technical success rates of MR elastography (MRE) according to established gradient-recalled echo (GRE) and spin-echo echo-planar imaging (SE-EPI) sequences and to compare liver stiffness (LS) values between the sequences during expiratory and inspiratory phases in patients with chronic liver disease or liver cirrhosis. METHODS: One hundred and eight patients who underwent MRE were included in this retrospective study. MRE was performed at 3 T based on both sequences during expiration as well as inspiration. Technical failure of MRE was determined if there was no pixel value with a confidence index higher than 95% and/or no apparent shear waves imaged. LS measurements were performed using free-drawing region of interest. To evaluate clinical factors related to the technical success rate of MRE, we assessed etiology of liver disease, ascites, body habitus, iron deposition, and liver morphology of patients. Statistical analysis was performed with the Wilcoxon test, Bland-Altman plot, independent t test, Mann-Whitney test, and McNemar test. RESULTS: The technical success rate of MRE in SE-EPI was significantly higher than that of GRE (98.1% vs. 80.7%, p < 0.0001). On the basis of univariate analysis, height, weight, and BMI were significantly associated with failure of MRE (p < 0.05). There was no significant difference in LS values between GRE and SE-EPI (2.82 kPa vs. 2.92 kPa (p > 0.05)). However, the LS values were significantly higher during inspiration than expiration with both GRE and SE-EPI (p < 0.0001). CONCLUSION: MRE in SE-EPI during expiratory breath-hold can be used as a reliable examination to evaluate liver fibrosis. KEY POINTS: • The technical success rate of MR elastography in spin-echo echo-planar imaging (SE-EPI) was significantly higher than that in gradient-recalled echo (GRE) during both the inspiratory and expiratory phases. • Liver stiffness values were significantly higher during inspiration than during expiration in both GRE and SE-EPI. • MR elastography in SE-EPI during expiratory breath-hold can be used as a reliable examination in patients with liver fibrosis.

Assessment of hepatic steatosis by using attenuation imaging: a quantitative, easy-to-perform ultrasound technique.

OBJECTIVES: To evaluate the diagnostic performance of attenuation imaging (ATI) in the detection of hepatic steatosis compared with a histopathology gold standard. METHODS: We prospectively enrolled 108 consecutive patients (35 males; median age, 54.0 years) who underwent percutaneous liver biopsy for evaluation of diffuse liver disease between January 2018 and November 2018 in a tertiary academic center. Grayscale ultrasound examination with ATI was performed just before biopsy, and an attenuation coefficient (AC) was obtained from each patient. The degree of hepatic steatosis, fibrosis stage, and necroinflammatory activity were assessed on histopathologic examination. The significant factor associated with the AC was found by a linear regression analysis, and the diagnostic performance of the AC for the classification into each hepatic steatosis stage was evaluated by receiver operating characteristic (ROC) analysis. RESULTS: The distribution of hepatic steatosis grade on histopathology was 53/11/22/16/6 for none/mild (< 10%)/mild (≥ 10%)/moderate/severe steatosis, respectively. The area under the ROC curve, sensitivity, specificity, and optimal cutoff AC value for detection of hepatic steatosis ranged from 0.843-0.926, 74.5-100.0%, 77.4-82.8%, and 0.635-0.745, respectively. Multivariate analysis revealed that the degree of steatosis was the only significant determinant factor for the AC. CONCLUSIONS: The AC from ATI provided good diagnostic performance in detecting the varying degrees of hepatic steatosis. The degree of steatosis was the only significant factor affecting the AC, whereas fibrosis and inflammation were not. KEY POINTS: • Attenuation imaging (ATI) is based on two-dimensional grayscale ultrasound images that can incorporate into routine ultrasound examinations with less than 2 min of acquisition time. • ATI provided good diagnostic performance in detecting the varying degrees of hepatic steatosis with an area under the ROC curves ranging from 0.843 to 0.926, and there was no technical failure in this study indicating high applicability of this technique. • The degree of hepatic steatosis was the only significant factor affecting the result of ATI examination.

Liver Ultrasound Elastography: An Update to the World Federation for Ultrasound in Medicine and Biology Guidelines and Recommendations.

The World Federation for Ultrasound in Medicine and Biology has produced these guidelines for the use of elastography techniques in liver diseases. For each available technique, the reproducibility, results and limitations are analyzed, and recommendations are given. This set of guidelines updates the first version, published in 2015. Since the prior guidelines, there have been several advances in technology. The recommendations are based on the international published literature, and the strength of each recommendation is judged according to the Oxford Centre for Evidence-Based Medicine. The document has a clinical perspective and is aimed at assessing the usefulness of elastography in the management of liver diseases.

Efficacy of Superb Microvascular Imaging for Diagnosing Acute Cholecystitis: Comparison with Conventional Ultrasonography.

We evaluated the diagnostic performance of ultrasonography (US) plus superb microvascular imaging (SMI) compared with conventional US alone for diagnosing acute cholecystitis. We included 54 patients with suspected biliary disease. The SMI pixel count showing flow signal was measured in the region of interest of the gallbladder bed of the liver. Two radiologists independently evaluated imaging features and rated five-point diagnostic likelihood level before versus after the additional SMI using the cutoff SMI pixel count. The SMI pixel count was significantly higher in acute than in non-acute cholecystitis (169.84 vs. 27.48, p < 0.001). The optimal SMI cutoff pixel count for predicting acute cholecystitis obtained by receiver operating characteristic curve was 56.67(82.8% sensitivity, 92.0% specificity). The area under the curve value was significantly higher after the additional SMI than before (0.798-0.863 vs. 0.701-0.736, p < 0.05). US plus SMI could objectively improve diagnostic performance compared with conventional US for acute cholecystitis.