The learning curve of contrast-enhanced 'microbubble' voiding urosonography-validation study.

INTRODUCTION: Vesicoureteral reflux (VUR) is a common pediatric urologic condition associated with urinary tract infection and pyelonephritis. It can be diagnosed via fluoroscopic voiding cystourethrogram (VCUG) and, more recently, contrast-enhanced voiding ultrasonography (ceVUS), which does not expose the patient to ionizing radiation. Voiding urosonography contrast agents used for the diagnosis of VUR have been widely available in Europe but were approved by the Food and Drug Administration for use in the United States only in 2016. OBJECTIVE: The objective was to optimize a protocol and compare the diagnostic performance of ceVUS to fluoroscopic VCUG in an academic medical center naïve to previous use of contrast-enhanced voiding urosonography. STUDY DESIGN: Thirty-nine patients referred for clinically indicated evaluation of VUR were enrolled between September 2016 and March 2017. Patients underwent contrast-enhanced ultrasonography with prediluted Lumason and under the same catheterization underwent fluoroscopic VCUG. Comparative grading was performed by pediatric radiologists on-site at the time of examination. RESULTS: Reflux was observed in 16 of 39 patients (20 of 64 renal units) ranging from grades 1 through 5. VCUG and ceVUS were concordant for detecting reflux in 10 of 39 patients (14 of 84 renal units) and excluding reflux in 23 of 39 patients (64 of 84 renal units) (Fig. 1). Using contrast enhanced voiding urosonography, 1 of 20 renal units had high-grade and 2 of 20 renal units had low-grade reflux that was not found on fluoroscopy. Using fluoroscopy, 1 of 20 renal units had high-grade and 2 of 20 renal units had low-grade reflux that had not been found on ceVUS. Two of 20 renal units were upgraded from low-grade on ceVUS to high-grade on fluoroscopy. This corresponds to a Cohen's kappa of 0.72 (confidence interval [CI] 0.54-0.91) or 'moderate.' DISCUSSION: During our investigation, we noted that there was a technical learning curve related to poor contrast mixing and the need to titrate the concentration of Lumason. However, over the course of the study, we were able to correct the technical aspects. Ultimately, our results showed good correlation between VCUG and Lumason ceVUS and only slightly less correlation than published studies by experienced centers. Future studies with voiding should allow for improved urethral visualization. CONCLUSION: While there is a considerable learning curve to the implementation of ceVUS for the diagnosis of pediatric VUR, these technical aspects can be corrected. Even a center previously naïve to contrast-enhanced ultrasound technology can, over a short period of time, demonstrate good correlation between VCUG and ceVUS in the diagnosis of VUR. Translation of ceVUS into clinical practice is an alternative to VCUG for diagnosis of reflux, is feasible, and can eliminate the radiation exposure associated with a VCUG.

[Management of fetal mediastinal shift: a practical approach]. / Conduite à tenir devant une déviation médiastinale fœtale: une approche pratique.

The purpose of this article is to review the technique of fetal chest ultrasound screening evaluation, the diagnostic work-up in the presence of fetal mediastinal shift and which ultrasound imaging features to look for. The first step in evaluating the fetal thorax is to confirm situs. Then, a median sagittal line is drawn from a four-chamber view to assist in spatial orientation followed by echotexture analysis of the structures of the thorax in the presence of mediastinal shift. We propose a systematic approach based on the direction of the mediastinal shift and echogenicity of the compressing hemithorax. When the hemithorax contralateral to the mediastinal shift is enlarged, which is the most frequent situation, diaphragmatic hernia and macrocystic congenital cystic adenomatoid malformation are the most likely etiologies when the mass is heterogeneous. Microcystic congenital cystic adenomatoid malformation, sometimes associated with sequestration, is the most frequent etiology when the mass is homogeneous. When the hemithorax ipsilateral to the mediastinal shift is small, which is less frequent, and the contralateral hemithorax is homogeneously isoechoic, then a diagnosis of lung hypoplasia-agenesis-aplasia should be considered.

Magnetic resonance imaging in the prenatal diagnosis of congenital diarrhea.

OBJECTIVE: Congenital diarrhea is very rare, and postnatal diagnosis is often made once the condition has caused potentially lethal fluid loss and electrolyte disorders. Prenatal detection is important to improve the immediate neonatal prognosis. We aimed to describe the prenatal ultrasound and magnetic resonance (MRI) imaging findings in fetuses with congenital diarrhea. METHODS: The study reports the pre- and postnatal findings in four fetuses that presented with generalized bowel dilatation and polyhydramnios. We analyzed the fetal ultrasound and MRI examinations jointly, then compared our provisional diagnosis with the amniotic fluid biochemistry and subsequently with the neonatal stool characteristics. RESULTS: In each of the four cases an ultrasound examination between 22 and 30 weeks' gestation showed moderate generalized bowel dilatation and polyhydramnios suggesting intestinal obstruction. MRI examinations performed between 24 and 32 weeks' gestation confirmed that the dilatation was of gastrointestinal (GI) origin, with a signal indicating intraluminal water visible throughout the small bowel and colon. The expected hypersignal on T1-weighted sequences characteristic of physiological meconium was absent in the colon and rectum. This suggested that the meconium had been completely diluted and flushed out by the water content of the bowel. The constellation of MRI findings enabled a prenatal diagnosis of congenital diarrhea. The perinatal lab test findings revealed two cases of chloride diarrhea and two of sodium diarrhea. CONCLUSION: Congenital diarrhea may be misdiagnosed as intestinal obstruction on prenatal ultrasound but has characteristic findings on prenatal MRI enabling accurate diagnosis; this is important for optimal neonatal management.

Normal pediatric testis: comparison of power Doppler and color Doppler US in the detection of blood flow.

PURPOSE: To compare power Doppler and conventional color Doppler ultrasound (US) in the detection of blood flow in the normal pediatric testis and to assess the symmetry of blood flow and the spectral Doppler tracing waveforms in the normal pediatric testis. MATERIALS AND METHODS: Testicular blood flow was assessed prospectively in 68 testes in 34 boys (age range, 6 weeks to 13 years; mean age, 4.6 years) with both conventional color and power Doppler US. Intratesticular blood flow was graded as follows: 0, no intratesticular flow; 1, single intratesticular Doppler signal identified; and 2, multiple intratesticular Doppler signals identified. The symmetry of intratesticular flow was assessed both subjectively and objectively by using the same grading system. Spectral Doppler tracings were obtained in 62 testes in 31 patients. RESULTS: Power Doppler US demonstrated intratesticular blood flow in 66 (97%) testes. Color Doppler US demonstrated intratesticular blood flow in 60 (88%) testes. Combined techniques depicted blood flow in all 68 (100%) testes. Testicular blood flow was judged symmetric in all 34 (100%) patients with power Doppler US and in 31 (91%) patients with color Doppler US. Spectral Doppler tracings demonstrated absence of diastolic flow in 20 (32%) of 62 testes. CONCLUSION: In children, power Doppler US is more sensitive than color Doppler US in the detection of intratesticular blood flow. With power Doppler US, testicular blood flow in healthy children is symmetric, underscoring that the asymptomatic testis can be used as a baseline for assessing flow in the symptomatic testis.

Use of Doppler ultrasonography in the evaluation of liver blood flow during silo reduction of a giant omphalocele.

Despite the utility of prosthetic silo reduction techniques, surgical treatment of giant omphaloceles containing herniated liver may result in acute compromise of hepatic vascular flow. The authors report a case of an infant with a giant omphalocele containing liver, in whom hepatic vascular compromise was suspected during the course of prosthetic visceral reduction. Doppler ultrasonography performed on the herniated liver through the prosthetic silo demonstrated triphasic vascular flow in the liver as well as normal hepatic venous flow and vena caval flow, and permitted continued gradual visceral reduction and a safe, delayed primary abdominal wall closure on the seventh day of life. Doppler ultrasonography performed through the silo may be an important diagnostic adjunct during the visceral reduction phase of staged abdominal wall closure in infants with giant omphaloceles.

Power Doppler imaging of focal lesions of the gastrointestinal tract: comparison with conventional color Doppler imaging.

To compare the usefulness of power Doppler imaging and color Doppler imaging in the vascular evaluation of gastrointestinal lesions, 21 patients with focal gastrointestinal tract lesions were examined with both power and color Doppler imaging. Two reviewers blinded to the diagnosis compared intramural vascularity detected by each of these methods. Power Doppler imaging detected flow in 16 patients with nonischemic lesions, whereas color Doppler imaging detected flow in only 11 patients. Neither modality detected flow in three patients with transmural infarction, but only power Doppler imaging detected minimal flow in the two patients with reversible ischemia. Power Doppler imaging improves visualization of intramural gastrointestinal vascularity, increasing the level of confidence in differentiating ischemic from nonischemic lesions.

Anatomic communications between the three retroperitoneal spaces: determination by CT-guided injections of contrast material in cadavers.

OBJECTIVE: A variety of retroperitoneal diseases such as pancreatitis, infection, and trauma may cause fluid collections in the three major retroperitoneal spaces. The purpose of our study was to elucidate flow patterns of fluid between the various compartments to assist the clinical-radiologic assessment and treatment of various retroperitoneal diseases. MATERIALS AND METHODS: In eight cadavers, CT guidance was used to selectively inject 35-1000 ml of contrast medium by hand or power injector into five perirenal, two posterior pararenal, and two anterior pararenal spaces. After the injections, CT of the entire abdomen and pelvis was done with 10-mm-thick sections at intervals of 10-40 mm. All images were reviewed in detail by a group of experienced body imagers to assess the pathways of flow of contrast material between the three major retroperitoneal spaces. RESULTS: The caudal cone of perirenal fascia was uniformly patent. A narrow channel connected the two perirenal spaces in the midline; the posterior border of this channel abutted the anterior margins of the abdominal aorta and the inferior vena cava. The perirenal, anterior pararenal, and posterior pararenal spaces all communicated with the infrarenal space, which in turn connected with the extraperitoneal spaces in the pelvis. When large quantities of contrast medium are injected in the perirenal or pararenal spaces and the infrarenal space is filled, the infrarenal space may then serve as a conduit across the midline of the abdomen. The anterior pararenal space crossed the midline and had a distinct retrorenal extension but no intraperitoneal connection. The slender posterior pararenal space had an anterolateral extension en route to the prevesical space. CONCLUSION: Our findings show pathways and extensions of the perirenal, anterior pararenal, and posterior pararenal spaces that should be considered when assessing a variety of retroperitoneal diseases. Perinephric collections, such as hematomas and urinomas, have at least a potential conduit across the midline or into the pelvis. Our study explains how blood from a ruptured abdominal aortic aneurysm may enter either perinephric space. Anterior pararenal processes, such as pancreatitis or appendicitis, can extend into the pelvis or cross the midline, and posterior pararenal blood from trauma can also flow into the pelvis.

Prevalence of ventriculomegaly in association with myelomeningocele: correlation with gestational age and severity of posterior fossa deformity.

PURPOSE: To investigate the relationship of ventriculomegaly (VM) with gestational age (GA) and the severity of the associated Chiari II malformation. MATERIALS AND METHODS: The sonograms of 51 fetuses with myelomeningoceles were retrospectively reviewed. VM was judged to be present when the transverse ventricular atrial diameter was greater than 10 mm. The severity of the posterior fossa (PF) deformity was subjectively graded as mild, moderate, or severe. Thirty-four fetuses were scanned at < or = 24 weeks GA, and 17 were scanned at > 24 weeks GA. RESULTS: The prevalence of VM was 61%. However, only 44% of fetuses < or = 24 weeks GA had VM, whereas 94% of fetuses > 24 weeks GA had VM. When compared with fetuses with mild PF deformities, fetuses with moderate or severe deformities had a higher prevalence of VM and the largest ventricles. CONCLUSION: The prevalence of VM in fetuses with myelomeningoceles varies with both GA and the severity of the associated PF deformity. These observations may provide additional prognostic information once a myelomeningocele is detected at sonography.

Perinatal and postnatal chest sonography.

Sonography is the primary method used to image the fetal chest. Many significant congenital anomalies such as pleural effusion, congenital diaphragmatic hernia, cystic adenomatoid malformation, pulmonary sequestration, and congenital heart disease can be detected during early prenatal sonography. Fetal sonography also permits accurate assessment of the severity of these processes, allowing for parental counseling and optimal planning of postnatal care. After birth, sonography is the primary method for evaluating cardiac anatomy and diagnosing congenital heart disease. Sonography also serves as a useful adjunct to plain film radiology and other modalities in evaluation of the mediastinum, diaphragm, pleura, and chest wall.

Sonography of the gravid uterus and placenta: current concepts.

Examination of the placenta and gravid uterus is an integral part of any obstetric sonographic study. Fetal well-being and growth depend on an intact uteroplacental vascular supply, and sonography can show most of the macroscopic abnormalities that may adversely affect the placenta or the gravid uterus, and thus compromise the fetus or affect the mode of delivery. The first part of this review will highlight sonography of normal uterine anatomy and pitfalls and review sonographic findings in cases of incompetent cervix, premature labor, and uterine synechiae. The second part will describe some recent advances in sonography of normal placental development and appearance, sonographic and anatomic variations, placental lesions, and implantation abnormalities.

Fibromuscular dysplasia with clotted renal artery aneurysm.

A six-year-old girl presented with hypertension and headaches. IVP demonstrated a subtle calcification medial to the left kidney and a non-functioning lower pole raising concern for tumor. Color Doppler ultrasound demonstrated normal flow to the upper pole of the left kidney and a severely attenuated avascular lower pole, which was confirmed with selective angiography. Pathology of the surgically resected left kidney showed a calcified large renal artery aneurysm containing thrombus associated with fibromuscular dysplasia. Unique findings in this case were the presence of wall calcification and intraluminal clot in the aneurysm which resulted in nonvisualization of the aneurysm and absent flow to the lower pole.

Prenatal diagnosis of autosomal recessive polycystic kidney disease: variable outcome within one family.

Autosomal recessive polycystic kidney disease is frequently diagnosed in utero by obstetric ultrasonography. We report a case in which there were varying outcomes of this disorder in three affected fetuses in a family. Recognition of variable expression within one family is important when parents are considering termination of a pregnancy with an affected fetus.

Elevated maternal serum alpha-fetoprotein: association with placental sonolucencies, fetomaternal hemorrhage, vaginal bleeding, and pregnancy outcome in the absence of fetal anomalies.

Elevated maternal serum alpha-fetoprotein (MSAFP) levels have been associated with an increased incidence of both placental sonolucencies and pregnancy complications. We designed a prospective study to test the hypothesis that the presence of these sonolucencies or a positive maternal Kleihauer-Betke stain would be associated with an elevated risk of obstetric complications. We enrolled 95 women with singleton pregnancies, elevated MSAFP, and no evidence of fetal anomalies on second-trimester ultrasound evaluation. Placental sonolucencies were documented at the time of ultrasound examination, and a maternal Kleihauer-Betke stain for fetal cells was obtained on the same day. Complications of pregnancy included fetal growth retardation, preterm delivery, late vaginal bleeding (at or after the 20th week of gestation), and fetal death. Women with elevated MSAFP had an increased incidence of placental sonolucencies, positive maternal Kleihauer-Betke stains, first-trimester vaginal bleeding, late vaginal bleeding, preterm delivery, fetal growth retardation, and fetal death compared with controls. Thirty-nine of 95 women with elevated MSAFP (41.1%) had at least one complication. In women with elevated levels, neither the presence of placental sonolucencies nor a positive Kleihauer-Betke stain correlated with first-trimester vaginal bleeding, the MSAFP level, or an increased risk of pregnancy complications. First-trimester vaginal bleeding was associated with an increased risk of preterm delivery in subjects with elevated MSAFP.

Radiographic findings associated with surfactant treatment.

Radiographs of the chest (CXR) were evaluated in 35 of 41 infants enrolled in a randomized controlled trial of modified bovine surfactant extract (Surfactant-TA Tokyo-Tanabe) treatment. Infants between birthweight 1000 and 1500 gm with respiratory distress syndrome requiring mechanical ventilation and an inspired oxygen concentration 0.4 or greater were randomly assigned to either a single intratracheal dose of saline or surfactant-TA prior to 8 hours of age. Radiographs obtained prior to treatment and 24 hours after treatment were reviewed by a radiologist (N.T.G.) without knowledge of treatment group. Evaluation consisted of a score including criteria for inflation of the lungs, density of the lungs, and extent of air bronchograms. Pneumothorax, pulmonary interstitial emphysema, and asymmetric parenchymal involvement were noted as well. No significant difference in CXR scores were noted in the two groups, before or after treatment. There was a greater incidence of pneumothorax and pulmonary interstitial emphysema in the control infants, which supports the role of surfactant in preventing barotrauma. Increased incidence of asymmetric parenchymal involvement was noted in the surfactant-treated infants. Further study of the possibility of drug maldistribution is warranted.

Rebound thymic hyperplasia five years after chemotherapy for Wilms' tumor.

Rebound thymic hyperplasia following chemotherapy is well documented, usually occurring within the first year. A delayed presentation makes distinction from an anterior mediastinal mass problematic in view of the increased risk of a second primary malignancy in pediatric cancer survivors. An unusual case of rebound thymic hyperplasia is described, presenting five years after completion of chemotherapy for Wilms' tumors.

Conjoined twins: prenatal diagnosis and assessment of associated malformations.

Prenatal diagnosis of conjoined twins is difficult and was rarely accomplished prior to the advent of sonography. Early prenatal diagnosis and assessment for shared vital organs are desirable for optimal obstetrical counseling and management. The authors retrospectively reviewed prenatal findings in 14 cases of conjoined twins. Thoracoomphalopagus was the most common type of conjoining, occurring in five cases (36%). Prenatal sonography showed shared hearts in nine (64%) cases, indicating severe conjoining and negligible chance for postnatal correction. Two sets of omphalopagus conjoined twins had separate hearts; however, severe congenital heart disease was present. Early prenatal diagnosis and assessment of the degree of conjoining provided couples with the option for pregnancy termination via vaginal delivery. In this series, nine patients elected pregnancy termination prior to 24 weeks and delivered vaginally. Transvaginal ultrasound significantly improved the delineation of conjunction in two patients, and computed tomography permitted the diagnosis to be confirmed in two patients.