Contrast-enhanced ultrasound of the spleen, pancreas and gallbladder in children.

Gray-scale and color/power Doppler ultrasound (US) are the first-line imaging modalities to evaluate the spleen, gallbladder and pancreas in children. The increasing use of contrast-enhanced ultrasound (CEUS) as a reliable and safe method to evaluate liver lesions in the pediatric population promises potential for imaging other internal organs. Although CEUS applications of the spleen, gallbladder and pancreas have been well described in adults, they have not been fully explored in children. In this manuscript, we present an overview of the applications of CEUS for normal variants and diseases affecting the spleen, gallbladder and pancreas. We highlight a variety of cases as examples of how CEUS can serve in the diagnosis and follow-up for such diseases in children. Our discussion includes specific examination techniques; presentation of the main imaging findings in various benign and malignant lesions of the spleen, gallbladder and pancreas in children; and acknowledgment of the limitations of CEUS for these organs.

Contrast-enhanced ultrasound of blunt abdominal trauma in children.

Trauma is the leading cause of morbidity and mortality in children, and rapid identification of organ injury is essential for successful treatment. Contrast-enhanced ultrasound (CEUS) is an appealing alternative to contrast-enhanced CT in the evaluation of children with blunt abdominal trauma, mainly with respect to the potential reduction of population-level exposure to ionizing radiation. This is particularly important in children, who are more vulnerable to the hazards of ionizing radiation than adults. CEUS is useful in hemodynamically stable children with isolated blunt low- to moderate-energy abdominal trauma to rule out solid organ injuries. It can also be used to further evaluate uncertain contrast-enhanced CT findings, as well as in the follow-up of conservatively managed traumatic injuries. CEUS can be used to detect abnormalities that are not apparent by conventional US, including infarcts, pseudoaneurysms and active bleeding. In this article we present the current experience from the use of CEUS for the evaluation of pediatric blunt abdominal trauma, emphasizing the examination technique and interpretation of major abnormalities associated with injuries in the liver, spleen, kidneys, adrenal glands, pancreas and testes. We also discuss the limitations of the technique and offer a review of the major literature on this topic in children, including an extrapolation of experience from adults.

Contrast-enhanced ultrasound of the kidneys and adrenals in children.

Pediatric applications of contrast-enhanced ultrasound (CEUS) are growing. Evaluation of the kidneys and adrenal glands in children using intravenous administration of US contrast agents, however, is still an off-label indication. Pediatric CEUS applications for kidneys are similar to those in adults, including ischemic disorders, pseudo- versus real tumors, indeterminate lesions, complex cystic lesions, complicated pyelonephritis, and abscesses. CEUS applications for evaluation of adrenal glands in children are limited, mainly focusing on the assessment and follow-up of adrenal trauma and the differentiation between an adrenal hemorrhage and a mass. This review addresses the current experience in pediatric CEUS of the kidneys and adrenal glands. By extrapolating the established knowledge for US contrast evaluations in the adult kidney to the pediatric context we can note opportunities for CEUS clinical use in children.

Contrast-enhanced ultrasound of benign and malignant liver lesions in children.

Contrast-enhanced ultrasound (CEUS) is increasingly being used in children. One of the most common referrals for CEUS performance is characterization of indeterminate focal liver lesions and follow-up of known liver lesions. In this setting, CEUS is performed with intravenous administration of ultrasound contrast agents (UCAs). When injected into a vein, UCA microbubbles remain confined within the vascular network until they dissipate. Therefore, visualization of UCA within the tissues and lesions corresponds to true blood flow. CEUS enables continuous, real-time observation of the enhancement pattern of a focal liver lesion, allowing in most cases for a definite diagnosis and obviating the need for further cross-sectional imaging or other interventional procedures. The recent approval of Lumason (Bracco Diagnostics, Monroe Township, NJ) for pediatric liver CEUS applications has spurred the widespread use of CEUS. In this review article we describe the role of CEUS in pediatric liver applications, focusing on the examination technique and interpretation of main imaging findings of the most commonly encountered benign and malignant focal liver lesions. We also compare the diagnostic performance of CEUS with other imaging modalities for accurate characterization of focal liver lesions.

European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB): An Update on the Pediatric CEUS Registry on Behalf of the "EFSUMB Pediatric CEUS Registry Working Group".

The European Federation of Ultrasound in Medicine and Biology (EFSUMB) created the "EFSUMB Pediatric Registry" (EFSUMB EPR) with the purpose of collecting data regarding the intravenous application of pediatric contrast-enhanced ultrasound (CEUS). The primary aim was to document the current clinical practice and usefulness of the technique and secondarily to assess CEUS safety in children. We issue the preliminary results of this database and examine the overall practice of CEUS in children in Europe.

Delayed contrast enhancement of hepatic parenchyma after intravenous sonographic contrast agent: unusual phenomenon. Case report and review of literature.

AIM: A case of heterogeneous late-phase hepatic enhancement (HLHE) using contrast-enhanced ultrasound (CEUS) with SonoVue is presented, where HLHE lasted after 50 min of injection. METHODS: This study aims to review prior literature on this topic, to characterize the features of HLHE in the liver, and to find possible and reliable explanations for this phenomenon. RESULTS: From literature, thus far five publications discuss this phenomenon with a total of 21 patients. CONCLUSION: We suggest that phagocytosis of contrast agent microbubbles by macrophages, and lymphocytosis of peripheral blood due to stress conditions of the patients might be in the background of HLHE.

Role of Contrast-Enhanced Ultrasound (CEUS) in Paediatric Practice: An EFSUMB Position Statement.

The use of contrast-enhanced ultrasound (CEUS) in adults is well established in many different areas, with a number of current applications deemed "off-label", but the use supported by clinical experience and evidence. Paediatric CEUS is also an "off-label" application until recently with approval specifically for assessment of focal liver lesions. Nevertheless there is mounting evidence of the usefulness of CEUS in children in many areas, primarily as an imaging technique that reduces exposure to radiation, iodinated contrast medium and the "patient-friendly" circumstances of ultrasonography. This position statement of the European Federation of Societies in Ultrasound and Medicine (EFSUMB) assesses the current status of CEUS applications in children and makes suggestions for further development of this technique.

[Evaluation of color Doppler imaging of ophthalmic tumors based on histopathologic findings]. / Szemészeti daganatok színkódolt ultrahangvizsgálatának értékelése a szövettani eredmény tükrében.

PURPOSE: To examine retrospectively the diagnostic and differential diagnostic value of color Doppler imaging (CDI) in cases of suspected intraocular and orbital tumors. PATIENTS AND METHODS: Color Doppler examination (using Acuson 128, Philips-ATL UM-9, HDI 3000, 5000, Siemens Elegra, GE Logiq9) was performed in a total of 194 patients (177 intraocular, 17 orbital tumors). The results were compared to the clinical findings (routine examination, conventional ultrasound examination) and the results of angiography (FLAG, ICG). Furthermore, in 73 cases histopathology records were obtained for comparison. RESULTS: Signs of blood flow could be detected in 137 cases (71%); the Doppler spectrum was low resistance in the large majority (130) of these cases. In cases where histopathology records were available, 60 of the 73 (82%) showed good concordance between the CDI diagnosis and the pathological results. CDI gave false positive results in 3, and false negative findings in 10 cases; the latter occurred mainly in small iris or ciliary body tumors. CONCLUSIONS: Using CDI, blood flow is demonstrable in the majority of intraocular and orbital tumors, especially if the tumor diameter is larger than 3 mm. CDI flow detection, however, is less reliable for iris or ciliary body tumors.

[Investigations of the blood supply of liver tumors--computerized tomography]. / Májdaganatok keringésvizsgálata. II. CT-vizsgálat.

The basic imaging method worldwide for the evaluation of the liver tumors before surgery and interventional treatments is spiral CT. CT is rapid, sensitive and accurate modality compared to US and it has become available in the past years in Hungary. Multislice CT represents further technical development which significantly shortened the examination time and CT-angiography can be performed at the same time with the evaluation of the liver parenchyma. CT should be performed prior guided biopsy in order to detect, to localize and to characterize all liver masses before the introduction of treatments. The follow up and the monitoring of the liver tumors after treatment is only reliable using the same type radiological studies which are performed on same way.

A review of nonconventional ultrasound techniques and contrast-enhanced ultrasonography of noncardiac canine disorders.

Modern ultrasound contrast media are gas-containing stabilized microbubbles that remain intact in the circulating blood for several minutes after intravenous injection and increase the intensity of the backscattered ultrasound. When the microbubbles disappear from the blood, they can be detected in the parenchyma of the liver and the spleen for about 30 more minutes (late liver- and spleen-specific phase). The insonated microbubbles produce second harmonic ultrasound frequencies, whose detection requires nonconventional ultrasound modalities such as pulsed inversion imaging. Nonconventional ultrasound techniques can also be used without microbubbles because second harmonics can be generated by ultrasound in tissues as well. The physical principles and advantages of nonconventional ultrasound techniques are described. The circulating microbubbles can be used not only to enhance weak Doppler signals, but also to perform dynamic contrast studies. Contrast-enhanced dynamic ultrasound studies--similar to contrast-enhanced CT and MRI examinations--have been used in humans to characterize lesions noninvasively (i.e., without biopsies) found during conventional ultrasound examinations. To map the distribution of contrast medium in a nodule or in an organ, specific scanning techniques such as stimulated acoustic emission have been developed. Stimulated acoustic emission occurs when high acoustic pressure ultrasonic waves disrupt the stationary or slowly moving microbubbles. This results in the release of a large amount of harmonic ultrasound frequencies. When the stimulated acoustic emission technique is used for dynamic studies, scanning must be interrupted several times to allow the microvasculature of the lesion to refill with microbubbles (interval delay imaging). The contrast patterns of malignant and benign hepatic nodules in humans have been the most intensively studied. Another type of dynamic study in humans measures the transit time of the contrast medium; that is, how fast the peripherally injected microbubbles reach the hepatic veins. Hepatic cirrhosis can be differentiated from other diffuse parenchymal liver diseases by a shorter transit time. Introducing nonconventional ultrasound techniques and ultrasound contrast media in veterinary diagnostic imaging may have potential value; however, intensive research should be carried out before ultrasound contrast agents can routinely be used in clinical practice.

Different autoregulation response to dynamic exercise in ophthalmic and central retinal arteries: a color Doppler study in healthy subjects.

PURPOSE: Prospective examination of the influence of changes in heart rate, arterial blood pressure and intraocular pressure induced by short dynamic exercise on orbital blood-flow velocities, and comparison of the autoregulation response in the ophthalmic artery and the central retinal artery. METHODS: Twelve young healthy volunteers were involved in the ophthalmic artery study and 12 others in the central retinal artery study. Blood-flow velocities were measured using color Doppler imaging before and after exercise. RESULTS: After exercise systolic blood pressure and heart rate were higher ( P<0.004) and intraocular pressure was lower ( P<0.006). However, in the central retinal artery the mean flow velocity, end-diastolic velocity and resistive indices remained stable, while in the ophthalmic artery these velocities actually decreased, and resistive indices increased significantly ( P<0.005). In the central retinal vein the velocities showed no significant change. CONCLUSION: Our results confirm the presence of an effective compensatory autoregulation for the retinal circulation, in connection with an increase in the ocular perfusion pressure induced by exercise. However, we found that in the ophthalmic artery some over-compensation occurs (significant decrease in some velocity parameters), whereas in the central retinal artery important flow parameters (mean velocity, end-diastolic velocity and resistive indices) appear to be successfully stabilized. Exercise history, heart rate, blood pressure and intraocular pressure all have to be monitored in orbital blood flow studies, as these variables are strongly affected by the changes in the autonomic nervous system and in turn significantly influence the measured flow velocity and resistivity values.

Observer experience improves reproducibility of color Doppler sonography of orbital blood vessels.

PURPOSE: The study investigated the reproducibility of orbital blood flow measurements with color Doppler imaging (CDI) at different stages of observer experience. METHODS: The subjects were 31 healthy volunteers and 2 sequential groups of 25 glaucoma patients each. Repeated blood flow measurements (usually 3 sets) in orbital vessels (ophthalmic artery, short posterior ciliary arteries, central retinal artery, and central retinal vein) were performed by the same observer in a single session in each subject. RESULTS: The parameters with the best reproducibility were the resistance index (mean coefficient of variation [COV], 3.3-8.8%), the peak systolic velocity (mean COV, 6.9-13.7%), the time-averaged velocity (mean COV, 7.2-16.0%), and the systolic acceleration time (mean COV, 8.8-12.3%). The mean COV was greater (9.9-20.3%) for the other arterial flow parameters (end-diastolic velocity and systolic acceleration) and for the venous flow velocities (maximum and minimum). The COVs of the parameters were improved by 20-40% as the observer became more experienced in ophthalmic CDI. CONCLUSIONS: We confirm the general reliability of CDI measurements in orbital vessels and show that observer experience improves reproducibility. It appears, however, that observer performance in these measurements is vessel specific.