Adrian Lim’s research while affiliated with Imperial College Healthcare NHS Trust and other places
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Vascular liver diseases (VLDs) include different pathological conditions that affect the liver vasculature at the level of the portal venous system, hepatic artery, or venous outflow system. Although serological investigations and sometimes histology might be required to clarify the underlying diagnosis, imaging has a crucial role in highlighting liver inflow or outflow obstructions and their potential causes. Cross-sectional imaging provides a panoramic view of liver vascular anatomy and parenchymal patterns of enhancement, making it extremely useful for the diagnosis and follow-up of VLDs. Nevertheless, multiparametric ultrasound analysis provides information useful for differentiating acute from chronic portal vein thrombosis, distinguishing neoplastic invasion of the portal vein from bland thrombus, and clarifying the causes of venous outflow obstruction. Color Doppler analysis measures blood flow velocity and direction, which are very important in the assessment of VLDs. Finally, liver and spleen elastography complete the assessment by providing intrahepatic and intrasplenic stiffness measurements, offering further diagnostic information.
Simple Summary
This review paper deals with incidentally found focal liver lesions (IFLLs) in otherwise healthy subjects, which is a frequent occurrence in daily practice. The clinical presentation and the imaging aspects play an important role in deciding whether and what further evaluation is required. In low-risk patients (i.e., those without a history of malignant or chronic liver disease or related symptoms, younger than 40 years old), more than 95% of IFLLs are benign. Shear Wave liver Elastography of the surrounding liver parenchyma should be considered to exclude liver cirrhosis and for further risk stratification. If an IFLL in a low-risk patient has a typical appearance on a B-mode ultrasound of a benign lesion, no further imaging is needed. Contrast-Enhanced Ultrasound (CEUS) should be considered as the first-line contrast imaging modality to differentiate benign from malignant IFLLs. In high-risk patients (i.e., with chronic liver disease or an oncological history), each IFLL should initially be considered as potentially malignant, and every effort should be made to confirm or exclude malignancy.
Abstract
An incidental focal liver lesion (IFLL) is defined as a hepatic lesion identified in a patient imaged for an unrelated reason. They are frequently encountered in daily practice, sometimes leading to unnecessary, invasive and potentially harmful follow-up investigations. The clinical presentation and the imaging aspects play an important role in deciding if, and what further evaluation, is needed. In low-risk patients (i.e., without a history of malignant or chronic liver disease or related symptoms), especially in those younger than 40 years old, more than 95% of IFLLs are likely benign. Shear Wave liver Elastography (SWE) of the surrounding liver parenchyma should be considered to exclude liver cirrhosis and for further risk stratification. If an IFLL in a low-risk patient has a typical appearance on B-mode ultrasound of a benign lesion (e.g., simple cyst, calcification, focal fatty change, typical hemangioma), no further imaging is needed. Contrast-Enhanced Ultrasound (CEUS) should be considered as the first-line contrast imaging modality to differentiate benign from malignant IFLLs, since it has a similar accuracy to contrast-enhanced (CE)-MRI. On CEUS, hypoenhancement of a lesion in the late vascular phase is characteristic for malignancy. CE-CT should be avoided for characterizing probable benign FLL and reserved for staging once a lesion is proven malignant. In high-risk patients (i.e., with chronic liver disease or an oncological history), each IFLL should initially be considered as potentially malignant, and every effort should be made to confirm or exclude malignancy. US-guided biopsy should be considered in those with unresectable malignant lesions, particularly if the diagnosis remains unclear, or when a specific tissue diagnosis is needed.
The manifestation of benign hematological infiltration in the liver is a challenge due to their rare occurrence and therefore, limited awareness and the general need for biopsy and histological confirmation. Owing to the rarity of these lesions, there are limited data concerning their appearance on ultrasound and, specifically, contrast-enhanced ultrasound. In a series of papers, we have compiled the US and CEUS characteristics of rare FLL, where there are few reports and images available, in order to build up a library of these cases. This paper describes the US and CEUS features of benign hematological FLL which include hepatic extramedullary hematopoiesis (EMH), hemophagocytic lymphohistiocytosis (HLH) and reactive lymphoid hyperplasia (RLH). Although these lesions occur rarely in the liver, their correct identification is imperative for appropriate patient`s management.
Background Attenuation coefficient (AC) and shear-wave speed (SWS) are established US markers for assessing patients with metabolic dysfunction-associated steatotic liver disease (MASLD), while shear-wave dispersion slope (DS) is not. Purpose To assess the relationship between the multiparametric US imaging markers DS, AC, and SWS and liver histopathologic necroinflammation in patients with MASLD. Materials and Methods This international multicenter prospective study enrolled consecutive patients with biopsy-proven MASLD between June 2019 and March 2023. Before biopsy, all participants underwent multiparametric US, and measurements of DS, AC, and SWS were obtained. Multivariable linear regression analyses were performed to assess the association of clinical variables and imaging markers with pathologic findings. The diagnostic performance of imaging markers for determining inflammation grade, steatosis grade, and fibrosis stage was assessed using the area under the receiver operating characteristic curve (AUC). Results A total of 124 participants (mean age, 53 years ± 15 [SD]; 62 males) were evaluated. In multivariable regression, lobular inflammation was associated with DS (regression coefficient, 0.06; P = .02), alanine aminotransferase level (regression coefficient, 0.002; P = .002), and Hispanic or Latino ethnicity (regression coefficient, -0.68; P = .047), while steatosis was associated with AC (regression coefficient, 3.66; P < .001) and fibrosis was associated with SWS (regression coefficient, 2.02; P < .001) and body mass index (regression coefficient, 0.05; P = .02). DS achieved an AUC of 0.72 (95% CI: 0.63, 0.82) for identifying participants with inflammation grade A2 or higher (moderate to severe inflammation). AC showed excellent performance for identifying participants with grade S1 (mild) or higher steatosis (AUC, 0.92 [95% CI: 0.87, 0.97]), while SWS showed excellent performance for identifying participants with fibrosis stage F2 or higher (clinically significant fibrosis) (AUC, 0.91 [95% CI: 0.86, 0.96]). Of the three US markers, SWS showed the highest AUC (0.81 [95% CI: 0.74, 0.89]) for the diagnosis of metabolic dysfunction-associated steatohepatitis. Conclusion Of the three US imaging markers (DS, AC, and SWS), DS was most associated with lobular inflammation grade at histologic examination and demonstrated fair diagnostic performance in distinguishing moderate to severe lobular inflammation. ClinicalTrials.gov Identifier: NCT04012242 Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Yin in this issue.
The 50th year of the European Federation of Societies in Ultrasound in Medicine and Biology (EFSUMB) has been celebrated 2022 publishing articles on the history of US. Contrast enhanced ultrasound (CEUS) allows to visualize blood flow and tissue perfusion. CEUS has proven to be safe without risk of nephrotoxicity. The availability of a contrast agent (tracer) for ultrasound imaging allows for the first time a dynamic assessment of tissue perfusion (blood flow and wash-in/wash-out pattern) which is an essential part for the detection and characterisation of pathological tissue and abnormal organ function. It was an outstanding achievement of academic centers in close cooperation with EFSUMB to investigate and validate the clinical potential of this new technology for the diagnosis and monitoring of various diseases and to develop clinical guidelines based on an in-depth assessment of the existing scientific publications. An important part of the implementation of CEUS in clinical practice was the development of contrast-specific imaging modes on the ultrasound scanners (in close cooperation with the machine manufacturers), the optimization of the machine setups for contrast imaging and the education provided to clinical users in form of workshops, webinars, textbooks and scientific congresses.
The diagnosis or rare, non-hematologic malignant lesions of the liver may be a challenge owing to the rarity of the disease, and is usually made by histological confirmation. Ultrasound with color Doppler and contrast-enhanced, if required, taking into account the clinical background of the patient, may help to focus the differential diagnosis. In this review, we describe the pathological and ultrasound features of rare malignant neuroendocrine and predominantly epithelioid liver lesions including primary neuroendocrine tumor of the liver, Invasive mucinous cystic neoplasm of the liver, and also hepatoblastoma.
... An editorial and booklet also summarize the birth and 50 years of EFSUMB [5,6]. In addition, the history of contrastenhanced ultrasound has been summarized [7]. Highlights of ultrasound over the past 70 years were summarized by Nielsen et al. [8]. ...
... [6,7] More recently, the guidelines have been commented and illustrated. [8][9][10][11][12][13][14][15][16][17][18][19] Improved detection and characterization of common focal pancreatic lesions such as ductal adenocarcinoma, neuroendocrine tumors, and pancreatic metastases are the main topics of these guidelines. The Asian Federation of Societies of Ultrasound in Medicine and Biology has established guidelines for contrast-enhanced EUS. ...
... [6,7] More recently, the guidelines have been commented and illustrated. [8][9][10][11][12][13][14][15][16][17][18][19] Improved detection and characterization of common focal pancreatic lesions such as ductal adenocarcinoma, neuroendocrine tumors, and pancreatic metastases are the main topics of these guidelines. The Asian Federation of Societies of Ultrasound in Medicine and Biology has established guidelines for contrast-enhanced EUS. ...
... However, the diagnostic utility of US is limited by the operator who requires a detailed knowledge of anatomic structures which may not conform to the appearance of orthogonal planes acquired during cross-sectional imaging. 12,13 In addition, normal fascial interfaces and tissue echogenicity may be altered by the effects of edema, hemorrhage, or surgical metalwork. An awareness of expected postoperative appearances as well as sufficient clinical history are essential to clinch the diagnosis. ...
... SWE offers both qualitative and quantitative assessments of liver stiffness and allows for a larger sampling area compared to ARFI. One of the key benefits of SWE is its ability to assess liver stiffness in real-time, allowing for dynamic evaluation during breathing cycles or in different body positions [12]. ...
... [6,7] More recently, the guidelines have been commented and illustrated. [8][9][10][11][12][13][14][15][16][17][18][19] Improved detection and characterization of common focal pancreatic lesions such as ductal adenocarcinoma, neuroendocrine tumors, and pancreatic metastases are the main topics of these guidelines. The Asian Federation of Societies of Ultrasound in Medicine and Biology has established guidelines for contrast-enhanced EUS. ...
... [6,7] More recently, the guidelines have been commented and illustrated. [8][9][10][11][12][13][14][15][16][17][18][19] Improved detection and characterization of common focal pancreatic lesions such as ductal adenocarcinoma, neuroendocrine tumors, and pancreatic metastases are the main topics of these guidelines. The Asian Federation of Societies of Ultrasound in Medicine and Biology has established guidelines for contrast-enhanced EUS. ...
... CT, MRI, and CEUS each have their own merits. Although CEUS has some limitations, such as operator dependency and a lack of strictly established machine standardization, its advantages include its renal non-toxicity, cost efficacy, and excellent temporal and spatial resolutions, offering dynamic imaging of more than 10 real-time images per second [8,[10][11][12]. This dynamic imaging permits us to observe hemodynamic changes in the liver [12]. ...
... As indicated, a definitive diagnosis may be difficult in a substantial number of cases [99,[113][114][115]. Regarding the further differential diagnoses in the non-cirrhotic liver, we refer to the current WFUMB CEUS liver guidelines and comments [39,88,99,[116][117][118][119]. ...
... More often, B-mode US alone cannot answer this question, except for the diagnosis of simple cysts (Figures 1 and 2), classical focal fatty infiltration or focal fatty sparing ( Figure 3) and typical hemangiomas (Figure 4). Doppler imaging techniques may not really help the characterization of IFLLs, since they have a relatively low sensitivity and specificity and can be susceptible to artifacts [86][87][88]. However, Color Doppler Imaging and in particular Microvascular Doppler techniques should always be used to identify IFLLs with a typical and diagnosis-proving vascular pattern, in particular focal nodular hyperplasia (FNH), with a spoke wheel pattern [87]. ...
