Showing papers in "Ultrasound Quarterly in 2006"

Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement

Abstract: The Society of Radiologists in Ultrasound convened a panel of specialists from a variety of medical disciplines to come to a consensus on the management of thyroid nodules identified with thyroid ultrasonography (US), with particular focus on which nodules should be subjected to US-guided fine needle aspiration and which thyroid nodules need not be subjected to fine-needle aspiration. The panel met in Washington, DC, October 26-27, 2004, and created this consensus statement. The recommendations in this consensus statement, which are based on analysis of the current literature and common practice strategies, are thought to represent a reasonable approach to thyroid nodular disease.

The kidney: imaging with microbubble contrast agents.

Abstract: Conventional ultrasonography of the kidney is faced by limitations due to the poor contrast of B-mode imaging for parenchymal disease and limited sensitivity of color Doppler for the detection of intracortical capillaries and deep pedicular vessels. Ultrasound contrast agents (USCAs) overcome these limitations, allowing the development of new applications for renal blood flow imaging and quantification. These improvements result from the increased acoustic response obtained from the microbubbles, as well as from the development of pulse sequences for bubble-specific imaging. In radiology, the liver has been considered as the primary target for contrast because USCAs allow both detection and characterization of focal lesions. The kidney has been less studied because USCA kinetics do not provide the same obvious potential for tumor characterization, and most clinical trials for contrast-enhanced renal imaging were conducted using color Doppler. Despite this, the kidney offers promising applications as USCAs improve the detection of abnormal microvascular and macrovascular disorders. Contrast-enhanced US may become the modality of choice for diagnosis of renal artery stenosis and detection of a perfusion deficit, as well as for characterization of indeterminate renal lesions, atypical cystic lesions, and the identification of acute pyelonephritis.

Microbubble contrast for radiological imaging: 1. Principles.

Abstract: Microbubble contrast for ultrasound imaging in radiology has finally come of age, adding entirely new capabilities to real time imaging. Following a bolus injection into a peripheral vein of as little as 0.1mL of an aqueous suspension, contrast specific imaging modes show parenchymal and lesional perfusion in real time in the major organs of the abdomen and pelvis as well as breast, thyroid and prostate. These new imaging modes exploit the unique interaction between ultrasound and microbubbles, which gives rise to nonlinear echoes that are readily distinguishable from those of tissue. Furthermore, microbubbles can be deliberately disrupted by the ultrasound imaging field. The rate at which fresh bubbles then replenish the scanplane can be metered in subsequent images, offering a means to quantify both flowrate and relative vascular volume of the microvasculature in both organs and solid lesions.

High-intensity focused ultrasound principles, current uses, and potential for the future.

Abstract: High-intensity focused ultrasound (HIFU) continues to be a very attractive option for minimally invasive procedures Using well-established principles, this ablative therapy can be used to treat a number of benign and malignant diseases with few side effects During the last 15 years, there has been an enormous amount of work, both laboratory based and in the form of clinical trials, aimed at developing devices that can deliver treatments with safe and effective outcomes In this article, we aim to outline the principles of HIFU, describe the current commercially available machines and their applications, and discuss the role of HIFU in the future

Imaging of malignant liver masses: characterization and detection.

Abstract: Noninvasive characterization of focal liver lesions is largely based on their enhancement patterns on contrast-enhanced imaging. The use of microbubble contrast agents combined with specialized ultrasound (US) techniques has significantly expanded the role of US in the diagnosis of focal liver lesions based on their vascularity and specific enhancement features. With the advantage of real-time scanning, contrast-enhanced ultrasound (CEUS) can evaluate small lesions that are indeterminate on computed tomography (CT) or magnetic resonance imaging (MR), because CEUS is far less affected by timing issues. Hepatocellular carcinoma is typically characterized by increased arterial flow with frequent dysmorphic tumor vessels and decreased portal venous flow. However, negative enhancement in the portal phase is often not obvious until late (>2 minutes). On the other hand, metastasis shows prompt brief arterial hypervascularity, with either a rim or diffuse pattern and rapid washout, seen as perfusion defects during the portal venous phase. This pattern of complete rapid washout of metastases within the homogeneously enhanced background liver parenchyma can improve their detection and also improve differentiation from hepatocellular carcinoma or benign focal lesions. All malignant lesions generally show negative enhancement or washout during the extended portal venous phase, and this pattern is useful to differentiate them from benign lesions. Microbubble agents, confined to the intravascular space, may infrequently characterize malignancy by showing washout whereas CT or MR shows persistent enhancement due to interstitial distribution.

Radiofrequency ablation of liver tumors: the role of microbubble ultrasound contrast agents.

Abstract: Radiofrequency ablation (RFA) is currently indicated for the treatment of primary and metastatic hepatic malignancies Real-time ultrasound (US) is generally used during the procedure to guide electrode placement, but for evaluating the results of treatment, contrast-enhanced computed tomography and magnetic resonance imaging have traditionally been considered more effective This view has changed, however, with the recent development of contrast-enhanced ultrasound (CEUS) (eg, using sulfur hexafluoride microbubbles), which can provide valuable information on the effects of RFA more rapidly and economically than computed tomography or magnetic resonance imaging without exposing the patient to ionizing radiation In our center, CEUS is performed in patients with liver tumors before and immediately after RFA, in selected cases during the procedure as well, and in the follow-up Between January 2003 and June 2005, we performed CEUS on 350 patients scheduled for RFA of primary or metastatic liver tumors In 14 (134%) of the 96 patients whose disease was metastatic, CEUS revealed lesions that had been missed on the conventional US examination In most of these cases, the result was a more complete treatment performed under CEUS guidance In the remaining 2 (14%) of 14, the results of the examination allowed us to avoid subjecting the patient to useless treatment In our experience, the use of CEUS also improved the management and follow-up of patients undergoing interstitial therapy

Sonography of the Abnormal Parathyroid Gland

Abstract: In 80% to 90% of patients with primary hyperparathyroidism, a single parathyroid adenoma will be identified as the culprit, whereas the remaining 10% to 20% are caused by multiple adenomas, parathyroid hyperplasia, and rarely, parathyroid carcinoma. At the 2002 National Institute of Health c

Sonography of benign intrascrotal lesions.

Abstract: Ultrasound plays an important role and adds essential information in diagnosing benign intrascrotal lesions. Characterization of benign intrascrotal lesions with sonography, in combination with clinical assessment, can lead to nonsurgical management or testicular sparing surgery. We present important sonographic features of benign intrascrotal lesions, including extratesticular lesions: adenomatoid tumors, papillary cystadenomas, spermatoceles, hydroceles, varicoceles, hernias; and intratesticular lesions: tunica albuginea cysts, testicular simple cysts, epidermoid cysts, tubular ectasia of the rete testis, intratesticular varicoceles, adrenal rest tumors, and splenogonadal fusion. The goal of this review is to provide the radiologist with a better understanding of benign lesions that occur in the scrotum.

Cellular and molecular imaging with targeted contrast ultrasound.

Abstract: There is growing interest in the availability of methods for imaging disease at the level of the cellular and/or molecular mediators. Techniques for imaging molecular alterations have been develop for essentially all non-invasive cardiac imaging modalities. Molecular imaging with contrast-enhanced ultrasound relies on the detection of novel site-targeted contrast agents. These microbubbles or nanoparticles are retained within regions of a specific disease process, thereby allowing phenotypic characterization of tissue. Since most of these tracers remain within the intravascular space, the disease processes assessed must be characterized by antigens that are expressed within the vascular compartment. Accordingly, the pathologic states that have been targeted include inflammation, ischemia-and tumor-related angiogenesis, and thrombus formation; all of which are mediated in part by molecular events within the vascular space. This review describes: 10 different strategies that have been employed to target ultrasound contrast agents to regions of disease, 2) the unique challenges for imaging targeted ultrasound contrast agents, and 3) some of the early experience imaging molecular events in animal models of disease.

Microbubble contrast for radiological imaging: 2. Applications.

Abstract: Conventional Doppler provides information on blood flow including both flow and direction and flow velocity. Information on the slowly flowing blood at the capillary level, however, has not previously been available on state of the art Doppler. Contrast enhanced ultrasound provides, for the first time, information on tissue perfusion such that CEUS may now play a role in liver mass characterization and the evaluation of masses in other solid viscera similar to the role of contrast enhanced CT and MR scan. Renal applications include similar mass characterization and evaluation of renal perfusion and the renal vasculature. Surveillance of aortic stent grafts, monitoring RFA, and evaluation of both prostate and breast masses are further areas of interest. Our experience with ultrasound contrast expands progressively, and essentially adds vascular information to any region when blood flow information is required. The addition of CEUS to clinical practice has significant impact on patient management. In patients with an incidental liver mass on sonography, for example, characterization at the time of tis detection reduces the time to diagnosis and decreases referrals to CT or MR scan. Ultrasound contrast agents are easy to use, have a very low incidence of adverse events, and are unaffected by renal function. As they add no radiation for their use, they are highly appropriate in pediatric and young adult patients. Ultrasound is enhanced by addition of contrast agents.

Benign liver masses: imaging with microbubble contrast agents.

Abstract: Benign focal liver lesions are frequently encountered in routine ultrasound (US) scanning as well as in staging US examination for the patients with known malignancy. Noninvasive characterization of benign liver masses by imaging features has been a challenge for the radiologist. Some benign liver masses show typical findings on US; however, these findings are not highly specific. Contrast-enhanced ultrasound (CEUS) is useful to make an instant, confident diagnosis of benign liver masses. Contrast-enhanced multiphasic computed tomography (CT) is an excellent imaging technique to detect and characterize focal liver masses. But there are a considerable number of indeterminate focal liver lesions, which require further evaluation. CEUS provides the evaluation of perfusion and hemodynamics of nodular liver lesions as well as real-time morphologic evaluation of lesion vascularity. Most benign liver masses show characteristic features on CEUS, allowing an accurate diagnosis. This review article describes typical enhancement features of common benign liver masses.

Focal tumor ablation: a new era in cancer therapy.

Abstract: This article describes an approach to image-guided tumor ablation, a major tool for cancer treatment in interventional oncology. An overview of the discipline of tumor ablation is followed by a review of the diseases affecting the liver; then, more in-depth discussion of percutaneous ethanol injection, radiofrequency ablation, cryoablation, and microwave ablation is offered. Inasmuch as ultrasound is usually the best imaging modality for applicator placement in the liver and kidney, particular attention will be given to the merits and techniques of this guidance method.

Endometriosis: sonographic spectrum.

Abstract: Endometriosis is the presence of functional endometrial tissue outside the uterine cavity and the myometrium. It is an important cause of infertility and pelvic pain in women older than 25 years. Endometriomas are relatively common and can mimic other adnexal masses, and ultrasonography is often the first choice of imaging. This pictorial essay presents the sonographic appearance of endometriomas and similar-appearing adnexal masses and their characteristics, which may aid in their differentiation on routine ultrasonographic examination.

Ultrasound-guided chest biopsies.

Abstract: Pulmonary nodules that are surrounded by aerated lung cannot be visualized with sonography. Therefore, percutaneous biopsy must be guided with computed tomography or fluoroscopy. Although this restriction only applies to central lung nodules, it has permeated referral patterns for other thoracic lesions and has retarded the growth of ultrasound-guided interventions. Nevertheless, sonography is an extremely flexible modality that can expeditiously guide many biopsy procedures in the thorax. Peripheral pulmonary nodules can be successfully biopsied with success rates exceeding 90% and complications rates of less than 5%. Orienting the probe parallel to the intercostal space facilitates biopsies of peripheral pulmonary nodules. Anterior mediastinal masses that extend to the parasternal region are often easily approachable provided the internal mammary vessels, costal cartilage, and deep great vessels are identified and avoided. Superior mediastinal masses can be sampled from a suprasternal or supraclavicular approach. Phased array probes or tightly curved arrays may provide improved access for biopsies in this location. Posterior mediastinal masses are more difficult to biopsy with ultrasound guidance because of the overlying paraspinal muscles. However, when posterior mediastinal masses extend into the posterior medial pleural region, they can be biopsied with ultrasound guidance. Because many lung cancers metastasize to the supraclavicular nodes, it is important to evaluate the supraclavicular region when determining the best approach to obtain a tissue diagnosis. When abnormal supraclavicular nodes are present, they often are the easiest and safest lesions to biopsy.

A practical approach to fetal chest masses

Abstract: The fetal thorax is visualized to a greater or lesser degree in every midgestation obstetrical sonogram during the evaluation of the fetal heart. Although the American Institute of Ultrasound in Medicine/American College of Radiology guidelines do not specifically allude to an obligation or expectation to detect fetal chest masses, images obtained for the heart, abdomen, and diaphragm will undoubtedly allow detection of most of serious fetal chest masses. In addition, fetal chest masses are being detected more frequently because of the increasing use of routine prenatal sonography, performed with modern high-resolution equipment. The following discussion is intended as an update on the sonographic diagnosis, natural history, and recommended management of fetal chest masses.

Controversies in transrectal ultrasonography and prostate biopsy.

Abstract: Transrectal ultrasound-guided biopsy of the prostate is the gold standard for the detection of prostate cancer. In its current form, transrectal gray-scale ultrasound is unable to differentiate malignant prostate tissue from benign tissue. The general indications for performing a sonographic guided biopsy of the prostate are an abnormal digital rectal examination or an abnormal prostate-specific antigen (PSA). Several controversial areas remain: the ideal number of biopsy cores, the use of PSA velocity, free PSA, PSA density, age- and race-adjusted PSA, the use of local anesthetics, and the overall best patient preparation methods, including such topics as routine antibiotic prophylaxis or bowel enemas, remain unsettled. There are also unanswered questions regarding repeat biopsy and protocols for managing patients with a diagnosis of high-grade intraepithelial neoplasia. This article will explore some of the current controversies and review the pertinent literature.

Ultrasound markers of fetal infection, Part 2: Bacterial, parasitic, and fungal infections

Abstract: Up to 1% of all pregnancies have clinically overt intra-amniotic bacterial infections, and an even larger percentage of pregnant women may be affected by silent infections. Although most pregnant women with overt intra-amniotic bacterial infection have experienced prolonged rupture of membranes (PROM), symptomatic and most silent nonviral intra-amniotic infections may occur with intact membranes. The etiology of intra-amniotic infection after PROM is almost always polymicrobial and consists of genital tract pathogens, such as group B streptococci, Chlamydia trachomatis, Neisseria gonorrhoeae, mycoplasmas, aerobic Gram-negative bacilli, such as the coliforms, and facultative and anaerobic endogenous organisms, such as peptococci, peptostreptococci, and Bacteroides species. These organisms gain access to the uterine cavity by the ascending route. Organisms such as Treponema pallidum, Listeria monocytogenes, Toxoplasma gondii, trypanosomes, and plasmodia are capable of gaining access to the amniotic cavity by transplacental hematogenous spread, and cause devastating fetal infections. Symptomatic intra-amniotic infection is usually a diagnosis of exclusion. Diagnostic criteria based on both clinical and laboratory findings lack sensitivity and are nonspecific. It is difficult to obtain uncontaminated intra-amniotic samples, especially when there is PROM. The problem is even greater with silent infections. In most cases, fetal infection is suspected after an unexplained and unexpected adverse outcome. Maternal morbidity is increased with intra-amniotic infection; although maternal mortality is extremely rare in developed countries, this is not the case in societies where pregnant women have limited or no access to medical care. Although infected women who are treated early and aggressively with wide-spectrum antibiotics do well, more than 10% of these women develop bacteremia and up to half of them will require cesarean delivery because of poor uterine contractions and arrest of labor. The overwhelming majority of term neonates exposed to intrauterine infection after PROM do well, but up to 30% of these neonates require treatment of neonatal pneumonia or bacteremia. Outcomes for preterm neonates or for neonates who experienced silent fetal infections are more severe. Morbidity and mortality rates in these cases are high, and survivors may have long-term devastating sequelae. The ability to identify ultrasound markers of fetal infection will help clinicians identify etiologic agents with greater accuracy and correlate these infections with specific antepartum and postpartum syndromes. The recognition of markers of intrauterine infection will also reduce unexpected adverse outcomes that result from undiagnosed fetal infections.

Ultrasound Markers of Fetal Infection, Part 2

Abstract: Up to 1% of all pregnancies have clinically overt intra-amniotic bacterial infections, and an even larger percentage of pregnant women may be affected by silent infections. Although most pregnant women with overt intra-amniotic bacterial infection have experienced prolonged rupture of membra

Solving the problem pelvic ultrasound with magnetic resonance imaging.

Abstract: Ultrasound is the screening method of choice for evaluation of pelvic anatomy and abnormalities of the female pelvis. It allows for detailed assessment of the uterus, endometrium, and ovaries. However, there are times when the sonographic diagnosis is nonspecific. This review article details the use of magnetic resonance imaging for assessment of uterine duplication anomalies, adnexal and uterine masses, and for aiding in the assessment of pregnant patients with nonspecific sonographic findings in the pelvis.

Aortic endografts: detecting endoleaks using contrast-enhanced ultrasound

Abstract: Evaluation of aortic endografts is an exciting new application for contrast enhanced ultrasound. Detection of endoleaks is critical as they may lead to progressive enlargement of a treated aneurysm with a risk of aneurysm rupture. In this article, contrast enhanced ultrasound is presented as a potentially accurate, safe and economical alternative to CTA, the current practice standard, for endoleak detection.

"Rule out ectopic": Asking the right questions, getting the right answers.

Abstract: Sonographic evaluation of the pregnant patient suspected of harboring an ectopic pregnancy (EP) helps determine patient management. Although clinicians typically ask sonologists to "rule out" EP in these patients, the sonologist actually must answer 3 questions: (1) Is there an intrauterine pregnancy (IUP)? (2) Is the possibility of normally developing IUP reliably excluded? (3) Are there sonographic findings that identify or increase the likelihood of an EP? Understanding the rationale behind these questions and the sonographic findings that help to answer these questions enables the sonologist to contribute meaningfully to the care of patients with possible EP. Beginning the sonographic examination with a limited transabdominal approach has value. An IUP can be confidently diagnosed by identification of an intradecidual sac exhibiting the double decidual sac sign, yolk sac, or embryo. When the serum β human chorionic gonadothropin exceeds 2000 mIU/mL, a technically excellent sonographic examination should identify an intradecidual sac potentially representing an IUP. Even without directly visualizing a yolk sac or embryo in the adnexa, the presence of an extraovarian mass or hemoperitoneum strongly predicts the possibility of EP. An intraovarian mass with peripheral hypervascularity is more likely to represent the corpus luteum rather than an intraovarian EP. Cervical EP can be distinguished from the cervical phase of a spontaneous abortion in progress by either demonstrating fetal heart motion or persistence or enlargement of findings on short-interval follow-up. Absence of a myometrial mantle surrounding one edge of an IUP positioned at the fundus is suspicious for an interstitial EP.

Topics in ultrasound education: Use of patient models to teach endovaginal ultrasound skills.

Abstract: Learning how to perform endovaginal pelvic ultrasound is often challenging for novices in a busy clinical practice. In this article, we describe a program in which we hired female patient models to help residents acquire basic endovaginal scanning skills.

Ultrasonography of the retrocrural region: normal and pathological findings.

Abstract: This pictorial essay illustrates normal and pathological findings in the region posterior to the diaphragmatic crura as demonstrated on ultrasound scans. Familiarity with the spectrum of normal and abnormal findings in this region will increase the diagnostic power of ultrasound scans of the upper abdomen.