Pediatric contrast-enhanced ultrasound in the United States: a survey by the Contrast-Enhanced Ultrasound Task Force of the Society for Pediatric Radiology.

BACKGROUND: The United States Food and Drug Administration (FDA) recently approved an ultrasound (US) contrast agent for intravenous and intravesical administration in children. OBJECTIVE: Survey the usage, interest in and barriers for contrast-enhanced US among pediatric radiologists. MATERIALS AND METHODS: The Contrast-Enhanced Ultrasound Task Force of the Society for Pediatric Radiology (SPR) surveyed the membership of the SPR in January 2017 regarding their current use and opinions about contrast-enhanced US in pediatrics. RESULTS: The majority (51.1%, 166) of the 325 respondents (26.7% of 1,218) practice in either a university- or academic affiliated group. The most widely used US contrast agent was Lumason® 52.3% (23/44). While lack of expertise and training were reported barriers, all respondents who are not currently using US contrast agents are considering future use. CONCLUSION: Interest in pediatric contrast US is very high. Education and training are needed to support members who plan to adopt contrast US into practice.

Use of ultrasound in diagnosing postoperative small-bowel intussusception in pediatric surgical oncology patients: a single-center retrospective review.

BACKGROUND: Postoperative intussusception can be a complication of abdominal surgery and often poses a diagnostic dilemma. OBJECTIVE: The purpose of this study was to evaluate the utility of ultrasonography in the diagnosis of intussusception in children who had recently undergone resection of a primary solid tumor. MATERIALS AND METHODS: We performed a retrospective review of all pediatric surgical oncology patients undergoing laparotomy for excision of an abdominal tumor at our institution from 1995 to 2015. We reviewed those with documented postoperative intussusception. In addition we searched the radiology database for all ultrasound examinations requested to rule out postoperative intussusception during our study interval. We analyzed demographics, primary diagnosis, surgical procedure, presentation, diagnostic investigations and definitive treatment. RESULTS: At our institution 852 laparotomies for abdominal tumor resection were performed during the study period, resulting in 10 postoperative intussusceptions (1.2% of cases), of which half were following neuroblastoma resection and the other half following nephrectomy for Wilms tumor. Postoperative intussusception was suspected if the patient had increasing nasogastric output, abdominal distension or feeding intolerance. Ultrasound was used to diagnose intussusception in 9/10 cases, on postoperative day 6 (standard deviation [SD] 5.6 days) on average, with a sensitivity of 89% (8/9; one false negative; 95% confidence interval [CI] 0.52, 1.00) and a specificity of 100% (no false positives; 95% CI 0.96, 1.00). CONCLUSION: Ultrasound was highly accurate in diagnosing postoperative intussusception in children who underwent resection of retroperitoneal tumors.

Use of Quantitative Dynamic Contrast-Enhanced Ultrasound to Assess Response to Antiangiogenic Therapy in Children and Adolescents With Solid Malignancies: A Pilot Study.

OBJECTIVE: The purpose of this study was to investigate contrast-enhanced ultrasound assessment of tumor response to antiangiogenic therapy in children and adolescents with solid malignancies. SUBJECTS AND METHODS: Children with recurrent solid tumors who were enrolled in an institutional phase 1 study of antiangiogenic therapy underwent contrast-enhanced ultrasound of target lesions before therapy, on therapy days 3 and 7, and at the end of course 1. Acoustic data from target lesion ROIs were used to measure peak enhancement, time to peak, rate of enhancement, total AUC, AUC during wash-in (AUC1), and AUC during washout (AUC2). The Cox regression model was used to assess the association between changes in parameters from baseline to follow-up time points and time to tumor progression. Values of p ≤ 0.050 were considered significant. RESULTS: Target lesion sites included liver (n = 3), pleura (n = 2), and supraclavicular mass, soft-tissue component of bone metastasis, lung, retroperitoneum, peritoneum, lymph node, muscle mass, and perineum (n = 1 each). Hazard ratios for changes from baseline to end of course 1 for peak enhancement (1.17, p = 0.034), rate of enhancement (3.25, p = 0.029), and AUC1 (1.02, p = 0.040) were significantly associated with time to progression. Greater decreases in these parameters correlated with longer time to progression. CONCLUSION: Contrast-enhanced ultrasound measurements of tumor peak enhancement, rate of enhancement, and AUC1 were early predictors of time to progression in a cohort of children and adolescents with recurrent solid tumors treated with antiangiogenic therapy. Further investigation of these findings in a larger population is warranted.

Distinguishing Osteomyelitis From Ewing Sarcoma on Radiography and MRI.

OBJECTIVE: The purpose of this study was to determine whether clinical and imaging features can distinguish osteomyelitis from Ewing sarcoma (EWS) and to assess the accuracy of percutaneous biopsy versus open biopsy in the diagnosis of these diseases. MATERIALS AND METHODS: Three radiologists reviewed the radiographs and MRI examinations of 32 subjects with osteomyelitis and 31 subjects with EWS to determine the presence of 36 imaging parameters. Information on demographic characteristics, history, physical examination findings, laboratory findings, biopsy type, and biopsy results were recorded. Individual imaging and clinical parameters and combinations of these parameters were tested for correlation with findings from histologic analysis. The diagnostic accuracy of biopsy was also determined. RESULTS: On radiography, the presence of joint or metaphyseal involvement, a wide transition zone, a Codman triangle, a periosteal reaction, or a soft-tissue mass, when tested individually, was more likely to be noted in subjects with EWS (p ≤ 0.05) than in subjects with osteomyelitis. On MRI, permeative cortical involvement and soft-tissue mass were more likely in subjects with EWS (p ≤ 0.02), whereas a serpiginous tract was more likely to be seen in subjects with osteomyelitis (p = 0.04). African Americans were more likely to have osteomyelitis than EWS (p = 0). According to the results of multiple regression analysis, only ethnicity and soft-tissue mass remained statistically significant (p ≤ 0.01). The findings from 100% of open biopsies (18/18) and 58% of percutaneous biopsies (7/12) resulted in the diagnosis of osteomyelitis, whereas the findings from 88% of open biopsies (22/25) and 50% of percutaneous biopsies (3/6) resulted in a diagnosis of EWS. CONCLUSION: Several imaging features are significantly associated with either EWS or osteomyelitis, but many features are associated with both diseases. Other than ethnicity, no clinical feature improved diagnostic accuracy. Compared with percutaneous biopsy, open biopsy provides a higher diagnostic yield but may be inconclusive, especially for cases of EWS. Our findings underscore the need for better methods of diagnosing these disease processes.

Safety of ultrasound contrast agents in the pediatric oncologic population: a single-institution experience.

OBJECTIVE: Little information is available regarding the safety of ultrasound contrast agents in children. The purpose of this article was to assess the safety profile of the i.v. administration of ultrasound contrast agents in the pediatric oncology population. MATERIALS AND METHODS: Patients with pediatric solid malignancies who were enrolled on institutional clinical trials conducted between June 2003 and January 2013 and who met our institutional screening criteria for contrast-enhanced ultrasound (CEUS) were eligible. After providing informed consent or assent for CEUS, subjects received i.v. bolus injections of one of two contrast agents for imaging of the primary tumor or a metastatic target lesion. Hemodynamic parameters, including heart rate, cardiac rhythm, and oxygen saturation, were monitored immediately before and for 30 minutes after the administration of the contrast agent. Interviews with the subject or a guardian were conducted by the principal investigator or a radiologist coinvestigator before and after the examination to assess for any adverse effects. RESULTS: Thirty-four subjects (21 male and 13 female) ranging in age from 8 months to 20.7 years (median, 8.7 years) underwent 134 CEUS. No detrimental change in hemodynamic status occurred in any subject. Three subjects (3/134, 2.2%) reported mild transient side effects on one occasion each, two (2/134, 1.5%) had taste alteration, and one (1/134, 0.8%) reported mild transient tinnitus and lightheadedness. These reactions did not recur in these subjects on subsequent CEUS examinations. CONCLUSION: The i.v. administration of ultrasound contrast agents is safe and well tolerated in the pediatric oncology population. Further studies in children are needed to confirm our findings.

Watchful waiting for some children with a mediastinal mass: the potential role for ¹8F-fluorodeoxyglucose positron emission tomography: a case report and review of the literature.

BACKGROUND: Benign hyperplastic thymus is a rare but important differential diagnosis of anterior mediastinal lesions. Histological and radiological criteria are used to distinguish this benign condition from other malignant diseases but have their limitations, and biopsy of mediastinal masses can be risky. We report for the first time the diagnostic value of fluorodeoxyglucose 18F positron emission tomography for patients with incidentally identified anterior mediastinal masses to avoid biopsy in some cases. CASE PRESENTATION: A 2 year old girl presented with new onset of emesis and constipation leading to the incidental discovery of an anterior mediastinal mass on radiograph. Chest computed tomography revealed cystic components within the mass concerning for a malignancy. Biopsy of the lesion and bone marrow aspiration and biopsy were negative but there was concern that the mediastinal biopsy may have missed the malignant component of the lesion. Hence, a positron emission tomography scan was obtained that showed mild homogeneous fluorodeoxyglucose 18F avidity within the mass similar to that of normal thymus. The diagnosis of benign hyperplastic thymus was made. CONCLUSION: The differential diagnosis of an incidentally found anterior mediastinal mass includes malignancy, but benign lesions such as benign hyperplastic thymus must also be considered, particularly when the complete blood count and biochemical profile are normal. Fluorodeoxyglucose 18F positron emission tomography can help guide a clinician's decision for further interventions and treatment.

An unusual case of Ogilvie syndrome in a pediatric oncology patient receiving palliative care after failed treatment with neostigmine.

BACKGROUND: We present a case of severe refractory constipation in an adolescent oncology patient with widely metastatic clear cell osteosarcoma who was ultimately found to have Ogilvie syndrome, also known as acute colonic pseudo-obstruction (ACPO). Ogilvie syndrome is characterized by dilatation of the large intestine in the absence of mechanical obstruction, usually occurring in adult patients with serious underlying medical conditions and rarely seen in children. It is likely that chronic narcotic use, abdominal metastasis, and a paraneoplastic process contributed to development of ACPO in this patient. DISCUSSION: This case highlights an infrequent, but important, gastrointestinal complication that can occur in pediatric patients with serious comorbid disease. Ogilvie syndrome should be included on the differential diagnosis list in pediatric patients with refractory constipation. Our case illustrates the progression of therapies, including surgical intervention that can be undertaken to treat this disorder in children and adults while providing important considerations for clinicians treating patients of any age with this unusual clinical complication.