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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., Competing Interests: Christoph F Dietrich: Speaker honoraria, Bracco, Hitachi, GE, Mindray, Supersonic, Pentax, Olympus, Fuji, Boston Scientific, AbbVie, Falk Foundation, Novartis, Roche; Advisory Board Member, Hitachi, Mindray, Siemens; Research grant, GE, Mindray, SuperSonic Richard G Barr: Speaker honoraria, Bracco, Hitachi, GE, Mindray, Supersonic, Philips, Siemens, Lantheus, Canon; Advisory Board – Lanteus and Bracco Diagnostics; Board Member – ICUS; Research Grants – Siemens Ultrasound, Philips Ultrasound, GE Ultrasound, GE Medical, Mindray, SuperSonic Imagine, B and K Ultrasound Annalisa Berzigotti: Research grant, Bracco Byung Ihn Choi: Speaker honoraria, Samsung Dirk André Clevert: Speaker honoraria, Bracco, GE, Samsung, Philips, Siemens, Falk Foundation Jean-Michel Correas: Speaker Honoraria, Canon MS, Hitachi MS, Philips US, SuperSonic Imagine, Novartis, Johnson & Johnson; Speaker honoraria, Bracco SA: Principal investigator of BR1-127 et SonoCap studies; Speaker honoraria, Guerbet SA: Principal investigator of NsSafe and Secure studies Odd Helge Gilja: Speaker honoraria, GE Healthcare, Takeda AS; Advisory Consulting, GE, Takeda and Samsung Vito Cantisani: Speaker honoraria, Samsung, Bracco, Canon J. Brian Fowlkes: Research grants, Philips Healthcare, GE Healthcare; Stock Ownership, Histosonics Adrian Lim: Advisory Board, Canon Medical Systems, Carestream; Research grant – Philips Medical Systems; Speaker honoraria – Canon, Bracco Maria Franca Meloni: Speaker honoraria, Bracco Christian Jenssen: Speaker honoraia, Hitachi, Bracco, Falk Foundation; Expert witness, Hitachi Mirko D’Onofrio: Speaker honoraria, Bracco, Siemens; Advisory Board, Bracco, Siemens, Hitachi; Research grant, Hitach; Congress Support, Bracco, Siemens Fabio Piscaglia: Speaker honoraria, Bracco, Bayer, EISAI, Guerbet; Advisory board honoraria: Bayer, EISAI; Research Contract: ESAOTE Masatoshi Kudo: Speaker honoraria, Bayer, Eisai, MSD, Ajinomoto; Research Grants, Chugai, Otsuka, Takeda, Taiho, Sumitomo Dainippon, Daiichi Sankyo, MSD, Eisai, Bayer, Abbvie, Medico’s Hirata, Astellas Pharma, Bristol-Myers Squibb; Advisory Consulting, Kowa, MSD, BMS, Bayer, Chugai, Taiho, Eisai, Ono pharmaceutical Yi Dong: Speaker honoraria, Bracco, Siemens Yuko Kono: Equipment support Canon, GE; Contast agent support Lantheus, Bracco Andrej Lyshchik: Speaker honoraria, GE Healthcare, Siemens, Canon; Advisory Board, Bracco Diagnostics; Consulting, GE Healthcare; Speaker panel, GE Healthcare, SonoScape; Royalties, Elsevier Zheng Rongqin: Speaker honoraria, Bracco, Esaote; Research grant, Philips; Congress support, Bracco Paul Sidhu: Speaker honoraria, Bracco, Siemens, Hitachi, GE healthcare, Philips, Samsung, Advisory Board ITREAS Ltd The following have declared no conflict of interest: Peter Burns, Cristina Chammas, Nitin G Chaubal, Pintong Huang, Andre Ignee, Nathalie Lassau, Jae-Young Lee, Yasunori Minami, Carlos Nicolau, Christian Nolsoe, Xin-Wu Cui, Adrian Saftoiu, Guido Torzilli, Ping Liang, Fuminori Moriyasu, Xiaoyan Xie, (Thieme. All rights reserved.)

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.

Background US has served as a standard surveillance tool for hepatocellular carcinoma (HCC); however, the detection rate and false referral rate with this modality are suboptimal. Purpose To evaluate the added value of perfluorobutane-enhanced US when combined with conventional B-mode US as an HCC surveillance tool in participants with liver cirrhosis. Materials and Methods This prospective multi-institution diagnostic trial ( https://ClinicalTrials.gov , NCT02188901) used an intraindividual comparison design in a single arm of study participants and was conducted at five referral hospitals. Eligible participants who had liver cirrhosis related to viral hepatitis and were undergoing US for HCC surveillance were enrolled from October 2014 to August 2016. Immediately after completion of B-mode US but before performance of perfluorobutane-enhanced US, operating radiologists entered the results of B-mode US. After completion of subsequent perfluorobutane-enhanced US (Kupffer phase with or without vascular-phase US), the radiologists recorded the results. The presence of HCC was confirmed either with pathologic analysis or radiologically by using dynamic contrast material-enhanced CT or gadoxetic acid-enhanced MRI. The primary end points were the detection rate of early-stage HCC (Barcelona Clinic Liver Cancer staging system stage 0 or A) and false referral rate. The primary end points were compared in a per-participant manner by using the McNemar test. Results A total of 524 participants (mean age, 54 years ± 9 [standard deviation]) were included. Of these, 493 (94.1%) had liver cirrhosis related to the hepatitis B virus. Ten HCCs were confirmed in eight participants. The detection rate of early-stage HCC was not significantly improved by adding perfluorobutane-enhanced US to conventional B-mode US (difference, 0.4% [95% confidence interval: -0.3%, 1.1%]; P = .16). The false referral rate was significantly reduced (difference, -3.2% [95% confidence interval: -5.0%, -1.4%]; P < .001). Conclusion The addition of perfluorobutane-enhanced US to conventional B-mode US reduced the false referral rate without a significant improvement in the detection rate of early-stage hepatocellular carcinoma for surveillance in a population in which the hepatitis B virus predominated. © RSNA, 2019 Online supplemental material is available for this article.

Objectives: To differentiate between large (≥ 1 cm in diameter) gallbladder (GB) non-neoplastic and neoplastic polyps using quantitative analysis of contrast-enhanced ultrasound (CEUS) findings., Methods: From September 2017 to May 2018, 29 patients (10 males; median age, 63 years) with GB polyps of ≥ 1 cm in diameter who were undergoing cholecystectomy were consecutively enrolled. All patients underwent preoperative conventional US and CEUS examinations. Quantitative analysis of CEUS findings using time-intensity curves between the two groups was independently performed by two radiologists. The interobserver agreement for the quantitative analysis of the CEUS results was measured using the intraclass correlation coefficient. Receiver operating characteristic analysis was performed to evaluate the diagnostic performance of CEUS examination., Results: After the cholecystectomy, the patients were classified into the non-neoplastic polyp group (n = 12) and the neoplastic polyp group (n = 17) according to the pathological results. The interobserver agreement for quantitative assessment between the two radiologists was near perfect to substantial. Quantitative assessment of the CEUS findings revealed that the rise time, mean transit time, time to peak, and fall time of non-neoplastic GB polyps were significantly shorter than those of neoplastic polyps (p < 0.001, p = 0.008, p = 0.013, and p = 0.002, respectively). The sensitivity and specificity of the quantitative CEUS parameters for the differentiation between the two groups were 76.5-100% and 75%, respectively, with an area under the curve of 0.765-0.887., Conclusions: Quantitative analysis of CEUS findings could be valuable in differentiating GB neoplastic polyps from non-neoplastic polyps., Key Points: • Quantitative analysis of CEUS findings could be valuable in differentiating gallbladder neoplastic polyps from non-neoplastic polyps. • Quantitative analysis of CEUS findings in gallbladder polyps provides cut-off values for differentiation between neoplastic polyps and non-neoplastic polyps with near-perfect to substantial interobserver agreement.

The purpose of our study was to investigate the diagnostic performance of 2-D ultrasound attenuation imaging (ATI) for the assessment of hepatic steatosis in patients with chronic liver disease using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard. We prospectively analyzed 87 patients with chronic liver disease who had reliable measurements at both ATI and MRI-PDFF. For the detection of hepatic steatosis of MRI-PDFF ≥5% and MRI-PDFF ≥10%, ATI measurements yielded areas under the receiver operating characteristic curve of 0.76 and 0.88, respectively (95% confidence intervals: 0.66-0.85 and 0.79-0.94). Attenuation coefficients at ATI were moderately correlated with MRI-PDFF (ρ = 0.66). In conclusion, attenuation coefficients at ultrasound ATI were well correlated with MRI-PDFF and, thus, may provide good diagnostic performance in the assessment of hepatic steatosis, making these coefficients a promising tool for the non-invasive assessment and quantification of hepatic steatosis., (Copyright © 2019 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Purpose To determine factors that significantly affect the focal disturbance (FD) ratio calculated with an acoustic structure quantification (ASQ) technique in a dietary-induced fatty liver disease rat model and to assess the diagnostic performance of the FD ratio in the assessment of hepatic steatosis by using histopathologic examination as a standard of reference. Materials and Methods Twenty-eight male F344 rats were fed a methionine-choline-deficient diet with a variable duration (3.5 days [half week] or 1, 2, 3, 4, 5, or 6 weeks; four rats in each group). A control group of four rats was maintained on a standard diet. At the end of each diet period, ASQ ultrasonography (US) and magnetic resonance (MR) spectroscopy were performed. Then, the rat was sacrificed and histopathologic examination of the liver was performed. Receiver operating characteristic curve analysis was performed to assess the diagnostic performance of the FD ratio in the evaluation of the degree of hepatic steatosis. The Spearman correlation coefficient was calculated to assess the correlation between the ordinal values, and multivariate linear regression analysis was used to identify significant determinant factors for the FD ratio. Results The diagnostic performance of the FD ratio in the assessment of the degree of hepatic steatosis (area under the receiver operating characteristic curve: 1.000 for 5%-33% steatosis, 0.981 for >33% to 66% steatosis, and 0.965 for >66% steatosis) was excellent and was comparable to that of MR spectroscopy. There was a strong negative linear correlation between the FD ratio and the estimated fat fraction at MR spectroscopy (Spearman ρ, -0.903; P < .001). Multivariate linear regression analysis showed that the degree of hepatic steatosis (P < .001) and fibrosis stage (P = .022) were significant factors affecting the FD ratio. Conclusion The FD ratio may potentially provide good diagnostic performance in the assessment of the degree of hepatic steatosis, with a strong negative linear correlation with the estimated fat fraction at MR spectroscopy. The degree of steatosis and stage of fibrosis at histopathologic examination were significant factors that affected the FD ratio. © RSNA, 2017 Online supplemental material is available for this article.

Purpose: To compare the diagnostic accuracy of transabdominal high-resolution ultrasound (HRUS) for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with endoscopic ultrasound (EUS) and pathology., Materials and Methods: Among 125 patients who underwent both HRUS and EUS, we included 29 pathologically proven cancers (T1 = 7, T2 = 19, T3 = 3) including 15 polypoid cancers and 50 surgically proven polyps (neoplastic = 30, non-neoplastic = 20). We reviewed formal reports and assessed the accuracy of HRUS and EUS for diagnosing cancer as well as the differential diagnosis of neoplastic polyps. Statistical analyses were performed using chi-square tests., Results: The sensitivity, specificity, PPV, and NPV for gallbladder cancer were 82.7 %, 44.4 %, 82.7 %, and 44 % using HRUS and 86.2 %, 22.2 %, 78.1 %, and 33.3 % using EUS. HRUS and EUS correctly diagnosed the stage in 13 and 12 patients. The sensitivity, specificity, PPV, and NPV for neoplastic polyps were 80 %, 80 %, 86 %, and 73 % using HRUS and 73 %, 85 %, 88 %, and 69 % using EUS. Single polyps (8/20 vs. 21/30), larger (1.0 ± 0.28 cm vs. 1.9 ± 0.85 cm) polyps, and older age (52.5 ± 13.2 vs. 66.1 ± 10.3 years) were common in neoplastic polyps (p < 0.05)., Conclusion: Transabdominal HRUS showed comparable accuracy for diagnosing gallbladder cancer and differentiating neoplastic polyps compared with EUS. HRUS is also easy to use during our routine ultrasound examinations., Key Points: • HRUS showed comparable diagnostic accuracy for GB cancer compared with EUS. • HRUS and EUS showed similar diagnostic accuracy for differentiating neoplastic polyps. • Single, larger polyps and older age were common in neoplastic polyps. • HRUS is less invasive compared with EUS.

Background: Ultrasonography (US) is widely used as a standard surveillance tool for patients who are at a high risk of having hepatocellular carcinoma (HCC); however, conventional B-mode US appears to be insufficient in order to ensure the early detection of HCC. Perfluorobutane allows very stable Kupffer phase imaging for at least 60 min, which is tolerable for examinations of the entire liver. The purpose of our study is to evaluate the added value of contrast-enhanced US using perfluorobutane to that of conventional B-mode US as an HCC surveillance tool for patients with liver cirrhosis., Methods/design: SCAN (Sonazoid-US for surveillance of hepatoCellulArcarciNoma) is a prospective, multi-institutional, diagnostic trial using an intra-individual comparison design in a single arm of patients. This study was approved by our five institutional review board and informed consent was obtained from all participating. We obtained consent for publication of these data (contrast enhanced US images, CT or MRI images, laboratory findings, age, sex) from all participating patients. All patients will undergo conventional B-mode US immediately followed by contrast-enhanced US. The standardized case report forms will be completed by operating radiologists after B-mode US and contrast-enhanced US, respectively. If any lesion(s) is detected, the likelihood of HCC will be recorded. The primary endpoints are a detection rate of early-stage HCC and a false referral rate of HCC. Intra-individual comparison using Mcnemar's test will be performed between B-mode US and contrast-enhanced US. The study will include 523 patients under HCC surveillance in five medical institutions in Korea., Discussion: SCAN is the first study to investigate the efficacy of contrast-enhanced US in surveillance using two reciprocal endpoints specialized for the evaluation of a surveillance test. SCAN will provide evidence regarding whether patients can truly benefit from contrast-enhanced US in terms of the detection of early stage HCC while avoiding additional unnecessary examinations. In addition to the study protocol, we elaborate on potentially debatable components of SCAN, including the design of an intra-individual comparison study, study endpoints, composite reference standards, and indefinite imaging criteria regarding the likelihood of HCC., Trial Registration: The date of trial registration (ClincalTrials.gov: NCT02188901 ) in this study is July 3, 2014. The last patient enrolled in August 30, 2016 and follow up to see the primary end point is still ongoing. All authors have no other relationships/conditions/circumstances that present a potential conflict of interest of relationships. Our study protocol has undergone peer-review by the funding body (GE Healthcare). No other relationships/conditions/circumstances that present a potential conflict of interest. Also, we clearly stated in the 'competing interests' section of my manuscript.

This prospective study investigated the usefulness of contrast (perfluorobutane-containing microbubbles)-enhanced ultrasound in the non-invasive assessment of liver allograft damage. Forty-one liver recipients underwent contrast-enhanced ultrasound followed by a liver biopsy. The hepatic filling rate (time between the arrival of contrast agent in the right hepatic artery and the maximum intensity of hepatic parenchyma) and parenchymal intensity difference before and after instantaneous high-power emission in the Kupffer phase were measured. Patients with allograft damage had higher hepatic filling rates and lower parenchymal intensity differences than those without damage (42.0 ± 16.9 vs. 30.5 ± 7.7 s, p = 0.005; 6.1 ± 7.4 vs. 16.6 ± 16.1 dB, p = 0.047, respectively). In the diagnosis of liver allograft damage, hepatic filling rate and parenchymal intensity difference had sensitivities of 61.5% and 90.9% and specificities of 92.6% and 63.6% using cutoffs of >38.5 s and ≤10.3 dB, respectively. In conclusion, contrast-enhanced ultrasound may be a promising tool in the detection of liver allograft damage., (Copyright © 2016. Published by Elsevier Inc.)

Goal: Effective speckle reduction in ultrasound B-mode imaging is important for enhancing the image quality and improving the accuracy in image analysis and interpretation. In this paper, a new feature-enhanced speckle reduction (FESR) method based on multiscale analysis and feature enhancement filtering is proposed for ultrasound B-mode imaging. In FESR, clinical features (e.g., boundaries and borders of lesions) are selectively emphasized by edge, coherence, and contrast enhancement filtering from fine to coarse scales while simultaneously suppressing speckle development via robust diffusion filtering. In the simulation study, the proposed FESR method showed statistically significant improvements in edge preservation, mean structure similarity, speckle signal-to-noise ratio, and contrast-to-noise ratio (CNR) compared with other speckle reduction methods, e.g., oriented speckle reducing anisotropic diffusion (OSRAD), nonlinear multiscale wavelet diffusion (NMWD), the Laplacian pyramid-based nonlinear diffusion and shock filter (LPNDSF), and the Bayesian nonlocal means filter (OBNLM). Similarly, the FESR method outperformed the OSRAD, NMWD, LPNDSF, and OBNLM methods in terms of CNR, i.e., 10.70 ± 0.06 versus 9.00 ± 0.06, 9.78 ± 0.06, 8.67 ± 0.04, and 9.22 ± 0.06 in the phantom study, respectively. Reconstructed B-mode images that were developed using the five speckle reduction methods were reviewed by three radiologists for evaluation based on each radiologist's diagnostic preferences. All three radiologists showed a significant preference for the abdominal liver images obtained using the FESR methods in terms of conspicuity, margin sharpness, artificiality, and contrast, p<0.0001. For the kidney and thyroid images, the FESR method showed similar improvement over other methods. However, the FESR method did not show statistically significant improvement compared with the OBNLM method in margin sharpness for the kidney and thyroid images. These results demonstrate that the proposed FESR method can improve the image quality of ultrasound B-mode imaging by enhancing the visualization of lesion features while effectively suppressing speckle noise.

The aim of this study was to determine the value of near-isovoxel ultrasound (ISUS) using xMATRIX technology in assessment of ductal communications with pancreatic cystic lesions. Twenty patients with pancreatic cystic lesions (n = 21) on magnetic resonance cholangiopancreatography (MRCP), underwent 2-D ultrasound (US) and subsequent ISUS using a matrix probe. Two observers assessed the presence of ductal communications with pancreatic cystic lesions for all MRCP, 2-D US, and ISUS images with multi-planar reformation, using a 5-point confidence scale. Weighted-κ statistics and intra-class correlation coefficients were calculated. Inter-observer agreement for MRCP, 2-D US and ISUS was moderate, fair and moderate (0.475, 0.222 and 0.472), respectively. The intra-class correlation coefficients between ISUS and MRCP was higher than that between 2-D US and MRCP (0.8706 vs. 0.5353, observer 1; 0.7206 vs. 0.4818, observer 2, respectively). Correlation and inter-observer agreement were better with MRCP than with 2-D US. We conclude that ISUS may be useful in evaluating ductal communications with pancreatic cystic lesions., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate the diagnostic performance of transabdominal high-resolution ultrasound (HRUS) for differentiation of adenomyomatosis from early-stage, wall-thickening-type gallbladder (GB) cancer., Methods: HRUS was defined as the addition of high megahertz imaging to conventional low megahertz imaging with use of state-of-the-art imaging technology. HRUS findings were retrospectively compared in 45 patients with adenomyomatosis and 28 patients with stage T1/T2 wall-thickening-type GB cancer. For evaluating HRUS performance in the differential diagnosis of adenomyomatosis from GB cancer, receiver operating characteristic curve analysis was used with a five-point confidence scale independently scored by three blinded radiologists who also analysed morphological abnormalities., Results: The area under the receiver operating characteristic curve (A (z)) values of HRUS in the diagnosis of adenomyomatosis were 0.948, 0.915 and 0.917 for reviewers 1, 2 and 3. Symmetrical wall thickening, intramural cystic spaces, intramural echogenic foci and twinkling artefacts were significantly associated with adenomyomatosis (P < 0.05), whereas irregular thickening of the outer wall, focal innermost hyperechoic layer (IHL) discontinuity, IHL irregularity, IHL thickening greater than 1 mm, loss of multilayer pattern in the GB wall, and intralesional vascularity were significantly associated with cancer (P < 0.05). The sensitivity, specificity and accuracy of intramural cystic spaces/echogenic foci for the diagnosis of adenomyomatosis were 80.0 %, 85.7 % and 82.2 %., Conclusions: This study showed that HRUS can be helpful for distinguishing adenomyomatosis from early-stage, wall-thickening-type GB cancer.

Objective: The purpose of this article is to describe the roles of sonography, MDCT, MRI, and direct cholangiography in the evaluation of hilar cholangiocarcinoma., Conclusion: Hilar cholangiocarcinoma is a primary malignant tumor typically located at the confluence of the right and left ducts within the porta hepatis. Staging of hilar cholangiocarcinoma with various imaging techniques is crucial for management, and a comprehensive approach is needed for accurate preoperative assessment.

Liver transplantation has been considered to be the only causal treatment for liver cirrhosis patients with hepatocellular carcinoma (HCC) due to its theoretical advantage of eliminating both the tumor and liver disease. However, because of the shortage of donor organs, it is strongly recommended that liver transplantations should be performed on cirrhotic patients with HCCs only when the patients meet the predetermined criteria in terms of number and extent of HCCs. Imaging is thus decisive in the patient inclusion or exclusion from transplantation lists. The imaging techniques used are CT, MRI and ultrasonography. The latter has been proven to be ineffective for HCC surveillance in transplant recipients because of its heavy operator dependence and unreliable detection of small and intermediately sized HCCs. The purpose of this article, then, is to systematically review the diagnostic performances of single-/multidetector row CT, dynamic gadolinium-enhanced MRI, superparamagnetic iron oxide (SPIO)-enhanced MRI and double-contrast MRI using both gadolinium and SPIO for the detection of HCCs with special emphasis on liver transplantation., (Copyright 2008 S. Karger AG, Basel.)

Objective: The purpose of this article is to describe the characteristic findings of intrapancreatic accessory spleen over time on contrast-enhanced sonography., Conclusion: On contrast-enhanced sonography, intrapancreatic accessory spleens showed a characteristic inhomogeneous enhancement on the early vascular phase, enhancement similar to the main spleen during the postvascular phases, and prolonged enhancement on the delayed hepatosplenic phase.

The clinical value of the reliability measurement index (RMI), newly added to point shear wave elastography (pSWE), was investigated. Forty-nine patients underwent both pSWE providing RMI (range: 0.0-1.0) and transient elastography (TE) before hepatic surgery. Interclass correlation coefficients (ICCs) between the median of the first two to nine measurements (as categorized by RMI values ≥0.0 (liver stiffness-reliability measurement index [LS-RMI] 0.0), ≥0.4 (LS-RMI 0.4) and ≥0.7 (LS-RMI 0.7) and the median of 10 consecutive measurements (LS-REF) were obtained. Compared with LS-REF, minimums of 7 LS-RMI 0.0, 5 LS-RMI 0.4 and 3 LS-RMI 0.7 measurements were required to obtain an ICC ≥0.95 with high inter-observer agreement (ICC ≥0.90). Diagnostic performance did not differ (p values >0.05) using these reduced numbers of LS measurements. Significant correlations were found between the reduced number of LS measurements and TE or METAVIR (p values <0.001). Therefore, RMI helped to improve reliability and reduce the number of LS measurements while maintaining the diagnostic performance of pSWE. [ABSTRACT FROM AUTHOR]

Purpose: Registration between 2D ultrasound (US) and 3D preoperative magnetic resonance (MR) (or computed tomography, CT) images has been studied recently for US-guided intervention. However, the existing techniques have some limits, either in the registration speed or the performance. The purpose of this work is to develop a real-time and fully automatic registration system between two intermodal images of the liver, and subsequently an indirect lesion positioning/tracking algorithm based on the registration result, for image-guided interventions. Methods: The proposed position tracking system consists of three stages. In the preoperative stage, the authors acquire several 3D preoperative MR (or CT) images at different respiratory phases. Based on the transformations obtained from nonrigid registration of the acquired 3D images, they then generate a 4D preoperative image along the respiratory phase. In the intraoperative preparatory stage, they properly attach a 3D US transducer to the patient's body and fix its pose using a holding mechanism. They then acquire a couple of respiratory-controlled 3D US images. Via the rigid registration of these US images to the 3D preoperative images in the 4D image, the pose information of the fixed-pose 3D US transducer is determined with respect to the preoperative image coordinates. As feature(s) to use for the rigid registration, they may choose either internal liver vessels or the inferior vena cava. Since the latter is especially useful in patients with a diffuse liver disease, the authors newly propose using it. In the intraoperative real-time stage, they acquire 2D US images in real-time from the fixed-pose transducer. For each US image, they select candidates for its corresponding 2D preoperative slice from the 4D preoperative MR (or CT) image, based on the predetermined pose information of the transducer. The correct corresponding image is then found among those candidates via real-time 2D registration based on a gradient-based similarity measure. Finally, if needed, they obtain the position information of the liver lesion using the 3D preoperative image to which the registered 2D preoperative slice belongs. Results: The proposed method was applied to 23 clinical datasets and quantitative evaluations were conducted. With the exception of one clinical dataset that included US images of extremely low quality, 22 datasets of various liver status were successfully applied in the evaluation. Experimental results showed that the registration error between the anatomical features of US and preoperative MR images is less than 3 mm on average. The lesion tracking error was also found to be less than 5 mm at maximum. Conclusions: A new system has been proposed for real-time registration between 2D US and successive multiple 3D preoperative MR/CT images of the liver and was applied for indirect lesion tracking for image-guided intervention. The system is fully automatic and robust even with images that had low quality due to patient status. Through visual examinations and quantitative evaluations, it was verified that the proposed system can provide high lesion tracking accuracy as well as high registration accuracy, at performance levels which were acceptable for various clinical applications. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the additional value of superb microvascular imaging (SMI) to characterize focal liver lesions (FLLs).Method: Between July 2020 and December 2020, 70 patients (39 men and 31 women; mean age [± standard deviation], 61.1 ± 10.1 years) with FLLs were prospectively enrolled and underwent B-mode ultrasound (US), color Doppler imaging (CDI), power Doppler imaging (PDI), and SMI examinations on the same day. All the malignant FLLs were confirmed by histological diagnosis, while the benign FLLs were confirmed by typical imaging features at contrast-enhanced CT and/or MRI. Tumor vascularity scores in CDI, PDI, and SMI were graded using a 5-point scale. For tumors in which vascularity was detected on SMI, tumor vascular pattern on SMI was assessed in each lesion. The diagnostic performance of a combination of B-mode US and SMI, based on vascular pattern on SMI, was compared to B-mode US alone to diagnose malignant lesions; and hemangiomas.Results: Seventy FLLs (34 benign [31 hemangiomas, 3 focal nodular hyperplasias] and 36 malignant tumors [16 hepatocellular carcinomas, 10 cholangiocarcinomas, 10 metastases]) were enrolled. Tumor vascularity score in SMI was significantly higher than those in CDI and PDI (P < 0.001). Using a combination of B-mode US and SMI, the diagnostic performance was improved from 0.867 and 0.834 to 0.945 and 0.921 (P = 0.035 and 0.112) to diagnose malignant tumors and from 0.896 and 0.853 to 0.975 and 0.987 (P = 0.027 and 0.006) to diagnose hemangiomas by reviewers 1 and 2, respectively.Conclusions: SMI provides higher sensitivity than CDI and PDI to detect tumor vascularity, and a combination of B-mode US and SMI can improve the characterization of FLLs when vascular pattern of tumor is considered. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The aim of this study was to determine the registration error of an ultrasound (US) fusion imaging system during an ex vivo study and its clinical value for percutaneous radiofrequency ablation (pRFA) during an in vivo study. Materials and methods: An ex vivo study was performed using 4 bovine livers and 66 sonographically invisible lead pellets. Real-time CT-US fusion imaging was applied to assist the targeting of pellets with needles in each liver; the 4 sessions were performed by either an experienced radiologist (R1, 3 sessions) or an inexperienced resident (R2, 1 session). The distance between the pellet target and needle was measured. An in vivo study was retrospectively performed with 51 nodules (42 HCCs and 9 metastases; mean diameter, 16mm) of 37 patients. Fusion imaging was used to create a sufficient safety margin (>5mm) during pRFA in 24 nodules (group 1), accurately target 21 nodules obscured in the US images (group 2) and precisely identify 6 nodules surrounded by similar looking nodules (group 3). Image fusion was achieved using MR and CT images in 16 and 21 patients, respectively. The reablation rate, 1-year local recurrence rate and complications were assessed. Results: In the ex vivo study, the mean target–needle distances were 2.7mm±1.9mm (R1) and 3.1±3.3mm (R2) (p >0.05). In the in vivo study, the reablation rates in groups 1–3 were 13%, 19% and 0%, respectively. At 1year, the local recurrence rate was 11.8% (6/51). In our assessment of complications, one bile duct injury was observed. Conclusion: US fusion imaging system has an acceptable registration error and can be an efficacious tool for overcoming the major limitations of US-guided pRFA. [Copyright &y& Elsevier]

Abstract: The purpose of our study was to investigate the relationship between a twinkling artifact and the biochemical compositions of gallstones in phantom experiments. Fifty-two gallstones surgically extracted from 26 patients (26 cholesterol, 12 brown pigment and 14 black pigment stones) were included in the phantom study. Color Doppler sonography was performed to evaluate the occurrence of a twinkling artifact behind the stones. The artifacts were graded from grade 0 (no artifact) to grade 3 (very strong artifact). Micro computed tomography (CT) images were obtained to analyze the internal architecture and external surface of the stones. A total of 20 of 26 cholesterol stones (77%) produced grade 2 or 3 artifacts, whereas almost all the black pigment stones and more than half of the brown pigment stones produced no artifacts or grade 1 artifacts (p = 0.0010). The sensitivity and specificity of grade 2 or greater artifacts for cholesterol stones were 76.9% and 76.9%, respectively. The composition of the stones was strongly correlated with the internal shape on the micro CT image. Cholesterol stones with rough surfaces did not show stronger intensities of the artifacts than those with smooth surfaces (p > 0.05). In conclusion, most of the prominent artifacts arose from cholesterol stones having radial or radial-concentric internal architectures, whereas the black pigment stones mostly produced little artifact. (E-mail: leejy4u@snu.ac.kr) [Copyright &y& Elsevier]

Abstract: This study was designed to investigate the potential usefulness of acoustic radiation force impulse (ARFI) elastography to evaluate focal solid hepatic lesions. In total, 51 patients with 60 focal hepatic lesions, which included 17 hemangiomas, 25 hepatocellular carcinomas (HCCs), 15 metastases and three cholangiocarcinomas, underwent ARFI elastography. The lesions were classified into three groups: Group I consisted of metastatic liver tumors and cholangiocarcinomas, group II consisted of HCCs and group III consisted of hemangiomas. The stiffness and conspicuity of the tumors as depicted on ARFI elastography and the echogenicity and conspicuity of the tumors on corresponding B-mode images were analyzed. Shear wave velocity was obtained to quantify stiffness for 36 focal hepatic lesions: 11 hemangiomas, 17 HCCs and eight other malignant lesions. On ARFI elastography images, group I tumors (n =18) appeared stiffer than the background liver for 13 lesions (72%), softer for two lesions and had identical stiffness in three lesions compared with the background liver. For group II tumors (n =25), 13 lesions (52%) appeared stiffer than the liver, six lesions appeared softer than the liver and the remaining six lesions showed the same stiffness as the liver. For group III tumors (n =17), six lesions (35%) appeared stiffer than the liver, seven lesions appeared softer and the remaining four lesions showed the same stiffness as the liver. There were no statistical differences among the three groups in terms of tumor stiffness as seen on ARFI elastography images (p >0.05). Of the 60 lesions, 41 (68%) displayed a clearer or equivalent margin on the ARFI elastography compared with that seen on B-mode images. The shear wave velocities were: Group I, 2.18±0.96m/s (mean value±SD); group II, 2.45±0.81m/s; group III, 1.51±0.71m/s (p =0.012). With a cut-off value of 2m/s for the shear wave velocity, the positive predictive value and specificity for malignancy were 89% and 81%, respectively. Images obtained with ARFI elastography provided additional qualitative information regarding the stiffness and tumor margin of liver tumors. By measuring shear wave velocity, quantification of stiffness was made possible and showed the potential to differentiate malignant hepatic tumors from hepatic hemangiomas. (E-mail: leejy@radiol.snu.ac.kr) [Copyright &y& Elsevier]

Abstract: Over the last few decades sonographic techniques have progressed remarkably. Recent advances in ultrasonography include harmonics, real-time spatial compound imaging, adaptive image processing, 3D power Doppler imaging and contrast-enhanced gray-scale harmonic ultrasonography. These advances have had positive effects on the diagnosis of hepatocellular carcinomas and on the evaluation of their responses to therapy. In this article, we review recent sonographic advances for the diagnosis and treatment of hepatocellular carcinomas and its typical imaging features. [Copyright &y& Elsevier]