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Radiofrequency ablation (RFA) is a thermal ablation technique widely used for the management of benign thyroid nodules. To date, five academic societies in various countries have reported clinical practice guidelines, opinion statements, or recommendations regarding the use of thyroid RFA. However, despite some similarities, there are also differences among the guidelines, and a consensus is required regarding safe and effective treatment in Asian countries. Therefore, a task force was organized by the guideline committee of the Asian Conference on Tumor Ablation with the goal of devising recommendations for the clinical use of thyroid RFA. The recommendations in this article are based on a comprehensive analysis of the current literature and the consensus opinion of the task force members.

Choledochal cysts rarely present with acute pancreatitis. We report a patient with type I choledochal cyst(s) who had concomitant acute frank hemorrhagic pancreatitis. A 14-year-old male noted with a history of recurrent abdominal pain, fever and jaundice. Ultrasonography (US) of abdomen at the Emergency Department depicted distended gall bladder with wall thickening. Apparently dilated intrahepatic ducts (IHDs) and fusiform dilatation of the common bile duct (CBD), and mild dilatation of the pancreatic duct were also noted, suggesting a type I choledochal cyst( ). Computed tomography (CT) demonstrated calcifications in the uncinate process of the pancreas in addition to the similar findings on US. He subsequently underwent choledochal cyst excision with a Roux-en-Y hepaticojejunostomy. After surgical treatment, he has been doing well for 3 years.

Purpose This study aims to evaluate patients with right-sided colonic diverticulitis detected at ultrasonography (US). Methods We retrospectively analyzed 14 patients. Demographic data, clinical features, and US images were documented. Results In the 14 patients, clinical manifestations included right lower abdominal tenderness (93%), leukocytosis (57.1%), and fever (28.6%). Diverticulitis occurred in cecum and ascending colon with a similar frequency (35.7%). US features included diverticular wall thickening (50%), surrounding echogenic fat (50%), intradiverticular echogenic material (50%), adjacent lymph node enlargement (21.4%), intradiverticular or peridiverticular fluid collection (28.6%), and color flow signals on or surrounding the diverticula (14.3%). Two (14.2%) patients suffered from recurrence. Two (14.3%) patients had abscess formation, and one (7.1%) patient had diverticulum perforation. Most (85.7%) patients received conservative treatment only. One (7.1%) patient received computed tomography-guided drainage due to diverticulum perforation and pocket of abscess formation. One patient underwent surgery due to recurrent diverticulitis-related fistula. Conclusion Common US features of diverticulitis include diverticular wall thickening, surrounding echogenic fat, and intradiverticular echogenic material. Proper recognizing of these features helps in differentiating diverticulitis from appendicitis and may obviate an unnecessary emergent surgery.

The outbreak of the SARS-CoV-2 infection, also known as coronavirus disease 2019 (COVID-19), was formally defined a pandemic by the World Health Organization (WHO) in March 2020, and is still a global health issue. Since there is a high prevalence of acute cardiac injury in patients with COVID-19 infection, point-of-care cardiac ultrasound (PoCCUS) may be used for longitudinal monitoring of patients infected with COVID-19. However, there is still limited experience on the application of PoCCUS in the COVID-19 pandemic. Within the point of care setting in our system, focused cardiac US exams were performed with specific imaging protocols on the basis of suspicion of a specific disease, such as ruling out tamponade or thrombotic complications. Our preliminary experience shows that PoCCUS helps distinguish the causes of dyspnea in febrile patients. The COVID-19 infection may play a role in unmasking or exacerbating underlying chronic cardiovascular conditions, especially in patients with inadequate past history. In hospitalized patients with COVID-19, CURB-65 score for pneumonia severity and raised D-dimer were significantly associated with deep vein thrombosis (DVT). COVID-19 patients with DVT had worse prognosis, and patients with lower leg edema deserve further evaluation by using point-of-care ultrasound for the lower legs and heart. In COVID-19 patients with arrhythmia, PoCCUS used by experienced hands may reveal abnormal right ventricle (RV) functional parameters and lead to a more comprehensive cardiac US study. When there is suspicion of cardiac disease, PoCCUS can be done first, and if information is inadequate, limited transthoracic echocardiography (TTE), and critical care echocardiography (CCE) can be followed. Ultrasound practitioners should follow the standard precautions for COVID-19 as outlined by the Centers for Disease Control and Prevention to prevent transmission of infection, regardless of suspected or confirmed COVID-19.

Background: The purpose of this study was to report the safety of perfluorobutane (Sonazoid) as a vascular-phase imaging agent in characterizing focal liver lesions (FLLs). Materials and Methods: From May 2014 to April 2015, a total of 54 individuals who received Sonazoid contrast-enhanced ultrasound (CEUS) were enrolled at 5 hospitals of 4 medical centers. All individuals were included in safety evaluation. A prospective study to evaluate the adverse effect (AE) incidences after intravenous administration of Sonazoid. Results: Sonazoid was well tolerated. Treatment-emergent adverse events (TEAEs) representing AE were recorded for 13 (24.1%) patients. The most common AE was abdominal pain (9.3%), followed by heart rate irregularity (5.6%). The majority of these patients (69.2%) experienced TEAEs that were mild in intensity. Sonazoid causes no significant AEs after intravenous injection. The only noteworthy AEs are related to tolerable myalgia (3.7%), abdominal pain (1.9%), and headache (1.9%). None of the 54 patients showed serious adverse effects. Conclusion: Sonazoid shows good safety and tolerance of intravenous use during CEUS of the liver for evaluation of FLLs.

Increased renal cortical echogenicity can be seen in patients with various underlying renal abnormalities. However, there are no reports of hyperechoic cortex associated with volume depletion until now. Here, we describe two cases of hyperechoic cortex caused by severe dehydration due to liver abscess and acute salmonellosis which lead to nausea, vomiting, and diarrhea. After administering large amounts of fluid supplements, the renal functions dramatically recovered and the echogenicity of the renal cortex returned to normal. Redistribution of renal blood flow and cortical ischemia may play a role in changes in echogenicity that occur in the renal cortex. Additionally, studies on increased renal cortical echogenicity and dehydration are reviewed.

A 21-year-old male patient presented with the symptoms of weakness in both legs, urine and stool incontinence for several months. Neurological examination revealed flaccid bilateral leg. Sonography showed heterogeneously echogenic multilobulated soft-tissue mass with several cystic spaces within it. Magnetic resonance imaging showed iso-signal intensity soft-tissue mass in T1 weighted imaging with many high-signal intensity cystic areas. After intravenous administration of gadolinium contrast agent, the tumor showed moderate contrast enhancement. The most common sarcomatous lesions with cystic degeneration include chondroid tumor (such as chondrosarcoma), liposarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumors. Tumor biopsy showed malignant peripheral nerve sheath tumor. The patient received arterial embolization, radiotherapy, and regular chemotherapy after the diagnostic workup.

To evaluate the role of three-dimensional power Doppler ultrasonography (3D-PDUS) in differential diagnosis of soft tissue masses. 93 patients with palpable soft tissue masses (age range = 14–88 years; mean age = 51.3 years, female:male = 19:74) were scanned with 3D-PDUS. The tumor was traced by the same doctor. The vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) were calculated automatically. All tumors were proved by US-guided biopsy or surgical pathology. Wilcoxin Rank Sums test was applied for statistical analysis. There were 25 benign and 67 malignant tumors. Benign tumors included hematoma (2), inflammation (3), hemangioma (1), lymphadenitis (2), and schwannoma (4). Malignant tumors included liposarcoma (2), synovial sarcoma (4), osteosarcoma (3), malignant fibrous histiocytoma (1), lymphoma (2), and metastasis (6). The VI, FI, and VFI were 4.76 ± 5.83, 32.41 ± 7.8, and 1.76 ± 2.39 in benign tumors, and were 5.28 ± 6.37, 33.08 ± 6.18, and 1.97 ± 2.87 in malignant tumors, respectively. There was no significant difference between benign and malignant tumor in VI, FI, and VFI ( p > 0.1). The 3D-PDUS could not be used as a single factor to differentiate the character of soft tissue tumors. Multiparameters in high-resolution ultrasound and color Doppler ultrasound should be considered.

Contrast-enhanced ultrasound (CEUS) has been used to diagnose gallbladder (GB) diseases for recent years because it is sensitive to visualize vascularity. Herein, we report a case who had a 1.7 cm × 1.2 cm polypoid lesion located in the gallbladder fundus with a feeding artery located in the stalk. On CEUS, the lesion showed early arterial phase enhancement (time to peak enhancement 18 s), persisting throughout the venous and delay phases. This enhancing pattern suggested that the lesion was a GB adenoma rather than a GB carcinoma. Cholecystectomy was performed, and pathology of the tissue revealed tubular adenoma of the GB.

The urinary bladder was one of the first of the body's systems to be investigated by ultrasound. The bladder can be scanned by the suprapubic transabdominal route, while the perineal and intravesical routes are practically not used. Ultrasonic visualization of the bladder and other pelvic structures necessitates a full bladder. The bladder must be examined when comfortably full. Ultrasonography is a convenient, safe and relatively inexpensive tool for urinary bladder examination. A wide variety of pathologies may involve the urinary bladder and these can be diagnosed by ultrasonography. However, comparatively less attention is paid to pathologies involving the bladder in the literature. We present the most common pathologies that may be encountered in day-to-day practice.

Portal vein aneurysms are focal dilatation of the portal venous system and have attracted clinical attention in recent years. The most common sites of portal vein aneurysms are the main portal vein and the confluence of the splenic and the superior mesenteric veins. The associated liver cirrhosis and portal hypertension have been thought to be main causes of portal vein aneurysms. We reported on an 86-year-old man with portal vein aneurysm. The imaging findings were presented and the relevant literature was also briefly reviewed.

Since the introduction of real-time ultrasonography (US) to the medicine in late 1970s, the unique benefit of the real-time cross-sectional imaging has made US one of the most widely used imaging modalities to guide interventional procedures. Among the intra-abdominal solid organs, the spleen is the least common solid organ considered for interventional procedures. Although splenic puncture for splenoportography was performed as early as the 1950s and has had a low complication rate, traditionally a direct splenic puncture is still avoided due to the risk of hemorrhage or laceration. US-guided percutaneous drainage of splenic abscesses has been used as a safe alternative procedure for more than 20 years, however, only a few series reporting such an interventional procedure have been published. This review describes briefly the usefulness, technique, safety, and the outcome of US-guided interventional procedures of the spleen.

Hepatocellular carcinoma (HCC) is one of the most common malignant neoplasms in the world and is the main cause of death in patients with liver cirrhosis. Surgical treatments including hepatic resection and liver transplantation are considered as the most effective treatment of HCC, however for various reasons, the vast majority of HCC patients are not suitable for surgery. Radiofrequency ablation (RFA) is a local ablation technique designed to destroy the tumor by heating. Alternating current passing from an electrode into the surrounding tissue causes ions to vibrate and generate heat in the tissue. Increased current leads to more vigorous ionic motion and increased temperature over a period of time, eventually leading to coagulation necrosis and cell death. The purpose of RFA treatment is complete tumor ablation with a margin of apparently normal tissue without collateral damage. The efficacy of RFA can be assessed with contrast-enhanced ultrasound, contrast-enhanced dynamic CT (CECT) or contrast-enhanced magnetic resonance imaging (MRI). A successful RFA treated area of HCC is nonenhancing on CECT and tends to be larger than the original tumor. A recent ablation area may have a circumferential rim of peripheral hyperemia from the host inflammatory response to thermal injury, which usually subsides a month after RFA. Discrete nodular noncircumferential enhancement, especially at the ablation margin, would raises suspicions of residual or recurrent tumors. The result of percutaneous RFA in the treatment of patients with HCC is very promising. The tumor size and the Child-Pugh class are two significant predictors of survival in RFA-treated patients. Comparative studies with surgical resection showed a promising survival rates with lower complication comparable to those of surgical resection. The complication rate following RFA varies from 2 to 10.6% and the mortality from 0 to 1.4%. In conclusion, RFA is a safe and highly effective treatment of HCC, especially for small tumors less than 3 cm in size. RFA technology and applications have progressed dramatically in the last few years. There are now well-documented roles for its use in a variety of circumstances. Although surgery is still the recommended treatment modality in patients with HCC, the majority of these patients are not surgical candidates. In the future RFA will likely play a significant role with a potential curative intent in the patients with HCC.

Ultrasonography (US) has been used as an important adjunct to mammography (MG) for about 20 years, and during this period the diagnostic accuracy of US has increased remarkably. A conventional 2-dimensional MG only detects a summation of the X-ray opacity of the whole thickness of breast tissue over the entire breast, while US can separately detect the sonographic properties of the breast tissue in a fashion of contiguous slices. Automated full-field breast US (AFBUS) scanners were originally designed to effectively examine the breast in its entirety. Basically, AFBUS scanners are either prone or supine types. The old generation prone-type scanner consists of a large water-filled tank with the transducers mounted at the base. The patient is prone with the breast freely suspended in the warm water bath. The first prone-type AFBUS scanner (Octoson, 3 to 4.5 MHz; Ultrasound Institute, Sydney, Australia) was used from the late 1970s to late 1980s. It was a specially designed scanner comprising eight transducers immersed at the base of a large water tank. When used for breast scanning, a combination of three to four transducers was usually utilized to obtain an optimal compound image of the breast. The Labsonics scanner, a representative scanner of old-generation supine type, was a simple B-mode single-crystal high-resolution automated unit (7.5 MHz; Labsonics, Indianapolis, IN, USA) that was used from the mid-1980s to mid-1990s. The scanner provided multiple static images of the breast. The patient was supine and a water bag technique was used for sound wave transmission to the breast. With the rapid development of computer technologies, volumetric ultrasound can now be applied for the breasts. Volumetric ultrasound scanning of the breast has been proposed as a complimentary modality for breast cancer screening. There are two types: compression and suspension; the latter is not commercially available outside Japan (ASU-1004, Aloka, Japan). The compression type consists of two major designs: upright and supine types. In the upright-type compression method, the breast is placed and compressed between a film sheet and a compression plate. The new supine-type compression AFBUS scanning apparatus comprises a rigid and substantially stationary frame and a compressive membrane (a polyester film sheet). By manually pushing the frame to contact firmly with the relatively soft breast, the transducer can optimally scan the breast if a sufficient amount of gel is evenly applied on the breast surface, leaving minimal or no contact artifacts. It was originally hoped that AFBUS would rival MG as a screening procedure in asymptomatic women. However, the images obtained from the automated scanners of the old generation were of inferior quality to those generated by hand-held real-time scanners. Nevertheless, the current automated scanners equipped with high-frequency broadband transducers are still significantly competing with hand-held instruments. The current high-resolution AFBUS scanners can provide better demonstration of the breast anatomy and proper orientation and documentation of the lesions detected, and therefore better reproducibility and are good for follow-up studies. The volumetric data obtained can provide potential information for computer-aided detection and diagnosis of breast lesions. With current volumetric technologies, the AFBUS system can provide even higher detection rate of lesions including solid lesions and carcinomas. Interpretation of the imaging results from the volumetric AFBUS should be based on all the imaging data obtained. The current AFBUS scanners are easy to use and need only a short period of training, and the examination technique is especially suitable for technologists or sonographers to perform the whole scanning procedure. AFBUS may be used as an adjunct to MG or as baseline US examination of the breast and can play an important role in screening nonpalpable tumors in women with dense breasts. However, AFBUS in its current form cannot replace MG in detecting malignancy presenting as only microcalcifications.

Intraneural ganglion is uncommon. We report a 49-year-old man with numbness of the left lower leg and foot drop for 1 month. High resolution ultrasonography (HRUS) showed a fusiform hypoechoic cystic structure, 5 × 0.5 cm in size, in the left lateral popliteal fossa which extended to below the fibula head region and which was encased by the epineurium of the left common peroneal nerve. Histology was compatible with ganglion. After operation, the patient recovered very well. This was correlated to a previous report in which the outcome essentially depended on the resectability of the lesion without nerve damage and the duration of symptoms. HRUS has the advantage of no radiation exposure, good resolution and high mobility. HRUS could be a valuable screening tool for soft tissue neoplasm and to differentiate it from the surrounding structure.

Primary granulocytic sarcoma (GS) of the breast is rare. The sonographic finding of GS is nonspecific, mainly noncalcified hypoechoic lesion with ill-defined margin and hypervascularity. Correct diagnosis is important to avoid unnecessary surgery. However, distinguishing GS from metastatic malignancies or other hematologic malignancies is difficult if there is a lack of clinical information of known hematologic disorders in the patient. We describe a 51-year-old woman who initially presented with bilateral breast masses in whom histologic study revealed a pattern of GS. She was finally diagnosed to have acute myelogenous leukemia.

Pulse inversion (PI) technique plays an important role in ultrasonic nonlinear imaging. For tissue imaging, PI technique provides suppression of spectral leakage and, thus, produces better image contrast. For contrast imaging, contrast between the agents and surrounding tissues are also enhanced with this technique by distinguishing nonlinear microbubbles from the background in either Doppler domain or radiofrequency domain. This paper reviews the theoretical backgrounds and relevant issues of the PI technique. Improvements in image contrast with the PI technique in both tissue harmonic imaging and contrast harmonic imaging are discussed in detail. In addition, potential motion artifacts and related contrast degradation are also included.

Thrombophlebitis of the superficial veins of the breast, also referred to as Mondor's disease, is a rare disease entity. Mondor reported the first superficial venous thrombosis of the chest wall in 1939. The major clinical manifestation is palpable and painful cord-like lesion in the breast. This condition is usually a benign, self-limiting process and requires only symptomatic treatment. The etiologic factors include trauma, surgery, infection, excessive physical activity, arthritis or breast carcinoma. Laboratory data are not helpful and biopsy is usually not advised. The use of grayscale and color Doppler ultrasound can aid in the diagnosis of Mondor's disease by its specific findings. Here, we present three women with Mondor's disease.

Free liquid silicone injections were used for breast augmentation in the 1950s and 1960s. Patients who received these breast silicone injections are now at the age of high breast cancer risk, but breast masses in such patients are difficult to detect by clinical examination and imaging studies. Ultrasonography may be affected by silicones, but lesions superficial to the silicones can still be detected. Here, we report one patient who received silicone injection 35 years ago when she was 18 years old. Ductal carcinoma in situ with clustered multiple microcalcifications was noted on ultrasound and confirmed by histopathologic examination. Surgery was performed and there was no evidence of recurrence 20 months after operation.

Nipple discharge, the spontaneous release of fluid from the nipple, is a common presenting finding that may be caused by an underlying intraductal or juxtaductal pathology, hormonal imbalance, or a physiologic event. Spontaneous nipple discharge must be regarded as abnormal, although the cause is usually benign in most cases. Clinical evaluation based on careful history taking and physical examination, and observation of the macroscopic appearance of the discharge can help to determine if the discharge is physiologic or pathologic. Pathologic discharge can frequently be uni-orificial, localized to a single duct and to a unilateral breast. Careful assessment of the discharge is mandatory, including testing for occult blood and cytologic study for malignant cells. If the discharge is physiologic, reassurance of its benign nature should be given. When a pathologic discharge is suspected, the main goal is to exclude the possibility of carcinoma, which accounts for only a small proportion of cases with nipple discharge. If the woman has unilateral nipple discharge, ultrasound and mammography are frequently the first investigative steps. Cytology of the discharge is routine. Ultrasound is particularly useful for localizing the dilated duct, the possible intraductal or juxtaductal pathology, and for guidance of aspiration, biopsy, or preoperative wire localization. Galactography and magnetic resonance imaging can be selectively used in patients with problematic ultrasound and mammography results. Whenever there is an imaging-detected nodule or focal pathology in the duct or breast stroma, needle aspiration cytology, core needle biopsy, or excisional biopsy should be performed for diagnosis. An excisional biopsy should be carried out with a thorough plan after a complete imaging evaluation. The evaluation of physiologic discharge or galactorrhea is primarily an assessment of endocrine factors.

Purpose To evaluate the role of color Doppler ultrasonography (CDUS) in verifying the closure of a dural arteriovenous (AV) fistula after r-knife radiosurgery (GKRS). Materials and Methods A total of 22 patients with dural AV fistulae, superior ophthalmic vein (SOV) drainage, and who had undergone GKRS therapy were followed up with CDUS until the closure was confirmed. The CDUS method was a trans-orbital scan with a focus on the evaluation of the SOV. The SOV was classified into three grades according to its velocity: severe, moderate and mild. All patients received angiography to confirm the findings of the CDUS. Results Before GKRS, CDUS revealed a reversed pulsatile flow (10 right SOVs, 8 left SOVs, and 4 bilateral SOVs). Six patients were graded as severe, eight as moderate, and eight as mild. All patients had their closure confirmed by CDUS, which was then further validated with angiography. Conclusion CDUS is an excellent modality for monitoring the hemodynamic changes in the SOV of patients with dural AV fistula following GKRS therapy. CDUS may become the modality for follow-up until complete closure occurs.

While shunts between portal and hepatic veins in Osler-Weber-Rendu disease have rarely been demonstrated in the liver, these portohepatic venous shunts (PHVS) may be revealed by ultrasound. However, direct evidence of PHVS on ultrasound may not be convincing. In this report, we demonstrate PHVS using ultrasound-guided percutaneous transhepatic portography with ultrasonic contrast agent (USCA) injection. With this technique, the microbubble-based USCA was depicted to enter the hepatic vein by way of the shunts and then flow into the inferior vena cava. The shunts were confirmed by iodinated contrast venography via the same sheathed needle.

Examination of lipomatous tumors with ultrasound (US) is generally limited to the soft tissue component of the mass and cortical contours of the involved bone. We report a patient with an intraosseous lipoma of the proximal radius with extra-osseous extension. US showed a heterogeneous hyperechoic mass lesion (3.5 × 3.0 cm in size) at the radial aspect of the left elbow, with bony cortex interruption. The lesion was associated with increased marginal color flow signals on color Doppler US study. Atypical lipoma or low-grade liposarcoma was diagnosed. The pathologic examination of the lesion demonstrated an abnormal collection of mature adipose tissue consistent with lipoma.