Hepatocellular Carcinoma in Non-Fibrotic Liver: A Narrative Review.

Hepatocellular carcinoma (HCC) in a non-fibrotic liver (F0) is considered to be rare, and there is a marked paucity of studies in the literature on this HCC type. A review of the literature shows some important clinical and tumor characteristics: (a) it occurs mainly in young female and elder male patients; (b) clinically, under normal hepatic function, alpha-fetoprotein level is often normal, and there are no risk factors; (c) associated with metabolic disease; (d) macroscopically, single large lesions are noted; and (e) microscopically, the lesions are well-differentiated and encapsulated. Radiological imaging results are straightforward, showing arterial hyperenhancement and later wash-out. The combined use of B-mode and contrast-enhanced (CE) ultrasound (US) is the most reliable and cost-effective diagnostic method. Few peri-and post-operative complications are noted and 5-year survival is not inferior to patients with HCC on fibrosis liver despite the lesion's large size. Most clinicians believe that HCC is unlikely to occur if patients have no symptoms and normal hepatic function. Although detailed clinical data are very limited, we expect that this review will help to improve the clinical management of HCC in non-fibrotic livers.

Factors other than fibrosis that increase measured shear wave velocity.

Shear wave elastography (SWE) is now becoming an indispensable diagnostic tool in the routine examination of liver diseases. In particular, accuracy is required for shear wave propagation velocity measurement, which is directly related to diagnostic accuracy. It is generally accepted that the liver shear wave propagation velocity reflects the degree of fibrosis, but there are still few reports on other factors that increase the shear wave propagation velocity. In this study, we reviewed such factors in the literature and examined their mechanisms. Current SWE measures propagation velocity based on the assumption that the medium has a homogeneous structure, uniform density, and is purely elastic. Otherwise, the measurement is subject to error. The other (confounding) factors that we routinely experience are primarily: (1) Conditions that appear to increase the viscous component; and (2) Conditions that appear to increase tissue density. Clinically, the former includes acute hepatitis, congested liver, biliary obstruction, etc, and the latter includes diffuse infiltration of malignant cells, various storage diseases, tissue necrosis, etc. In any case, it is important to evaluate SWE in the context of the entire clinical picture.

One-day seminar for residents for implementing abdominal pocket-sized ultrasound.

Despite its proven high utility, integration of pocked-sized portable ultrasound (US) into internal medicine residency training remains inconsistent. For 10 years, we have held a 1-d seminar biannually, consisting of lecture (half-day) and hands-on training (half-day) on pocket-sized US of the abdomen and lungs. The lecture consists of training on US physics and clinical applications of pocket-sized US, followed by a lecture covering the basic anatomy of the abdomen and lungs and introducing the systemic scanning method. Given the simple structure of pocket-sized US devices, understanding the basic physics is sufficient yet necessary to operate the pocket-sized US device. It is important to understand the selection of probes, adjustment of B mode gain, adjustment of color gain, and acoustic impedance. Basic comprehension may have a significant positive impact on the overall utilization of pocket-sized US devices. The easiest and most reliable way to observe the whole abdomen and lungs is a combination of transverse, sagittal, and oblique scanning, pursuing the main vascular system from the center to the periphery of the organ in the abdomen and systemic scanning of the pleura. There is usually a marked change in knowledge and attitudes among the program participants, although skill gaps remain among them. We discuss the limitations and problems to this education system as well.

Refraction artifact on abdominal sonogram.

Ultrasonography (US) is the first-line diagnostic tool for observing the whole abdomen. Unfortunately, a wide spectrum of refraction-related artefactual images is very frequently encountered in routine US examinations. In addition, most practitioners currently perform abdominal US examinations without sufficient knowledge of refraction artifacts (RAs). This review article was designed to present many representative RA images seen in the clinical setting, with a brief explanation of the mechanism of these images, in certain cases through an analyzed and reconstructed method using computer simulation that supports clinical observations. RAs are encountered not only with B-mode US but also with Doppler US, contrast-enhanced US, and shear wave elastography. RAs change their appearance according to the situation, but they always have a significant effect on detailed interpretation of abdominal US images. Correct diagnosis of abdominal US relies on a deep understanding of each characteristic artifactual finding, which necessitates knowledge of basic US physics. When analyzing mass lesions, computer simulation analysis helps to reveal the global images of RAs around a lesion.

Diagnostic problems in two-dimensional shear wave elastography of the liver.

Two-dimensional shear wave elastography (2D-SWE) is used in the clinical setting for observation of the liver. Unfortunately, a wide spectrum of artifactual images are frequently encountered in 2D-SWE, the precise mechanisms of which remain incompletely understood. This review was designed to present many of the artifactual images seen in 2D-SWE of the liver and to analyze them by computer simulation models that support clinical observations. Our computer simulations yielded the following suggestions: (1) When performing 2D-SWE in patients with chronic hepatic disease, especially liver cirrhosis, it is recommended to measure shear wave values through the least irregular hepatic surface; (2) The most useful 2D-SWE in patients with focal lesion will detect lesions that are poorly visible on B-mode ultrasound and will differentiate true tumors from pseudo-tumors (e.g., irregular fatty change); and (3) Measurement of shear wave values in the area posterior to a focal lesion must be avoided.

Hereditary hemorrhagic telangiectasia: how to efficiently detect hepatic abnormalities using ultrasonography.

INTRODUCTION: Hereditary hemorrhagic telangiectasia (HHT) is a multiorgan genetic angiodysplastic affection characterized by visceral vascular malformations. It affects mainly the brains, lungs, gastrointestinal tract, and nasal mucosa. Unlike those organs, hepatic involvement, although very frequently occurring, is insufficiently recognized, mainly because of the complex vascular structure of this organ. Thus, treating HHT patients requires a solid understanding of these hepatic anomalies. It is especially important for any general clinicians to be able to recognize clinical findings in HHT, which leads to a high suspicion of HHT and have an index of suspicion for liver abnormalities of HHT. For this purpose, keen awareness of clinical as well as hepatic sonographic (US) findings is paramount. AIM: The aim of this review is to summarize previously reported findings on the hepatic US through a thorough analysis of related articles, and to (a) determine the role of US in the diagnosis of hepatic involvement in HHT patients and (b) propose the most simple and easy way to detect HHT-related abnormalities during routine US examinations. CONCLUSION: Hepatic US serves to diagnose the detailed complex hepatic changes typical of HHT, and contributes to increased diagnostic confidence of hepatic changes in HHT patients, with the most simple way not to overlook HHT-related abnormalities being to find hepatic artery dilatation.

Range-ambiguity artifact in abdominal ultrasound.

Range-ambiguity artifacts (RAAs) are an erroneous mapping of returning echoes into a composite picture. The purpose of this review was to illustrate the mechanism of RAAs and to present the diagnostic problems caused by RAAs. RAA features differ slightly from organ to organ. At the level of the urinary bladder, RAAs take the form of a cloud-like, ill-demarcated, immobile, echogenic area, and the depth of the echogenic area differs depending on the pulse repetition frequency (PRF). This form is referred to as "static RAA" in this review. There are two key ultrasound characteristics of RAAs at the level of the liver: (a) the depth of RAAs change according to the PRF, and (b) RAAs move in accordance with the cardiac cycle. This form is referred to as "mobile RAA" in this review. At the level of the gallbladder, RAAs take the form of fine echogenic lines in the gallbladder. This phenomenon is actually a combination of two phenomena: a ring-down artifact and RAA. This form is referred to as "complex RAA (searchlight phenomenon)" in this review. The easiest way to reduce RAAs is to change the image depth. Sufficient knowledge of RAAs can prevent misdiagnosis of erroneously displayed returning echoes as real pathologic changes.

Multinodular fatty change in the liver in three patients with chronic hepatic porphyria: Contribution of sonography to the diagnosis.

We present three cases of chronic hepatic porphyria (CHP) in alcoholic patients, in which grayscale ultrasound (US) revealed multiple echogenic masses in the liver, mimicking multinodular hepatocellular carcinoma on alcoholic liver injury. In all cases, contrast-enhanced US (CEUS) showed iso-enhancement of the mass lesions throughout all vascular phases. Additionally, two-dimensional shear wave elastography (2DSWE) (performed in two cases) revealed the mass to have almost the same SWE value as the surrounding parenchyma. When encountering alcoholic patients with multiple echogenic masses in the liver, CHP must be included in the differential diagnosis. CEUS and 2DSWE allow us to increase our diagnostic confidence of CHP.

Hepatocellular carcinoma in otherwise sonographically normal liver.

PURPOSE: Hepatocellular carcinoma (HCC) on normal liver is very rare. The goal of this study was to determine the clinical manifestations and the role of ultrasonography (US) in the diagnosis of HCC arising in normal liver. METHODS: The clinical data and US findings in 12 cases of surgically resected HCC in normal liver were retrospectively analyzed. RESULTS: The patients were asymptomatic, had no hepatocarcinogenic factor, and hepatic function tests were almost normal in most cases. HCCs were large, encapsulated, and solitary, and there were predominantly well-differentiated or moderately differentiated in most cases. US showed a hypoechoic rim and lateral shadowing, suggestive of peritumoral capsule formation, and on contrast-enhanced US (CEUS), the tumor was hyperenhanced in arterial phase and washed out in postvascular phase, revealing typical HCC findings. CONCLUSIONS: US raises suspicion of HCC by showing lateral shadowing on grayscale ultrasound and hypervascularity on CEUS of the lesion.

Superb microvascular imaging (SMI) findings of splenic artery pseudoaneurysm: a report of two cases.

Splenic artery pseudoaneurysm (SAPA) is a relatively infrequently encountered but clinically important vascular change, because it carries a high risk of rupture that warrants prompt treatment regardless of its size. Thus, sufficient knowledge is indispensable when seeing chronic pancreatitis patients or post-traumatic patients. Here, we report two such cases. The first case was a 52-year-old woman known to have chronic pancreatitis who presented with hematemesis and hemodynamic instability in which X-ray computed tomography (CT) and color Doppler sonography (CDS) had difficulty visualizing slow blood flow in SAPA, but superb microvascular imaging (SMI) clearly demonstrated the slow blood flow in SAPA, prompting our therapeutic decision to perform rapid embolization. The second case was a 51-year-old woman with post-traumatic SAPA in which 3D SMI enabled us to understand more clearly the topographic relationship between multiple SAPAs as compared with conventional US, leading to a decision to provide immediate surgical treatment. SMI was thought to provide a new insight into the US diagnosis of SAPA. When examining patients suspected of having a SAPA, SMI is an indispensable diagnostic tool at present.