Abdominal ultrasonography of the pediatric gastrointestinal tract.

Ultrasound is an invaluable imaging modality in the evaluation of pediatric gastrointestinal pathology; it can provide real-time evaluation of the bowel without the need for sedation or intravenous contrast. Recent improvements in ultrasound technique can be utilized to improve detection of bowel pathology in children: Higher resolution probes, color Doppler, harmonic and panoramic imaging are excellent tools in this setting. Graded compression and cine clips provide dynamic information and oral and intravenous contrast agents aid in detection of bowel wall pathology. Ultrasound of the bowel in children is typically a targeted exam; common indications include evaluation for appendicitis, pyloric stenosis and intussusception. Bowel abnormalities that are detected prenatally can be evaluated after birth with ultrasound. Likewise, acquired conditions such as bowel hematoma, bowel infections and hernias can be detected with ultrasound. Rare bowel neoplasms, vascular disorders and foreign bodies may first be detected with sonography, as well. At some centers, comprehensive exams of the gastrointestinal tract are performed on children with inflammatory bowel disease and celiac disease to evaluate for disease activity or to confirm the diagnosis. The goal of this article is to review up-to-date imaging techniques, normal sonographic anatomy, and characteristic sonographic features of common and uncommon disorders affecting the gastrointestinal tract in children.

ACR Appropriateness Criteria Fever Without Source or Unknown Origin-Child.

The cause of fever in a child can often be determined from history, physical examination, and laboratory tests; infections account for the majority of cases. Yet in 20%, no apparent cause can be found, designated as fever without source (FWS). The yield of chest radiography in children with FWS is low, and it is usually not appropriate. However, in children with respiratory signs, high fever (>39°C), or marked leukocytosis (≥20,000/mm(3)), chest radiography is usually appropriate, as it has a higher yield in detecting clinically occult pneumonia. In newborns with FWS, there is higher risk for serious bacterial infection, and the routine use of chest radiography is controversial. In children with neutropenia, fever is a major concern. In some clinical circumstances, such as after hematopoietic stem cell transplantation, chest CT scan may be appropriate even if the results of chest radiography are negative or nonspecific, as it has higher sensitivity and can demonstrate specific findings (such as lung nodule and "halo sign") that can guide management. In a child with prolonged fever of unknown origin despite extensive medical workup (fever of unknown origin), diagnosis is usually dependent on clinical and laboratory studies, and imaging tests have low yield. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The incidental pulmonary nodule in a child. Part 2: Commentary and suggestions for clinical management, risk communication and prevention.

The incidental detection of small lung nodules in children is a vexing consequence of an increased reliance on CT. We present an algorithm for the management of lung nodules detected on CT in children, based on the presence or absence of symptoms, the presence or absence of elements in the clinical history that might explain these nodules, and the imaging characteristics of the nodules (such as attenuation measurements within the nodule). We provide suggestions on how to perform a thoughtfully directed and focused search for clinically occult extrathoracic disease processes (including malignant disease) that may present as an incidentally detected lung nodule on CT. This algorithm emphasizes that because of the lack of definitive information on the natural history of small solid nodules that are truly detected incidentally, their clinical management is highly dependent on the caregivers' individual risk tolerance. In addition, we present strategies to reduce the prevalence of these incidental findings, by preventing unnecessary chest CT scans or inadvertent inclusion of portions of the lungs in scans of adjacent body parts. Application of these guidelines provides pediatric radiologists with an important opportunity to practice patient-centered and evidence-based medicine.

The incidental pulmonary nodule in a child. Part 1: recommendations from the SPR Thoracic Imaging Committee regarding characterization, significance and follow-up.

No guidelines are in place for the follow-up and management of pulmonary nodules that are incidentally detected on CT in the pediatric population. The Fleischner guidelines, which were developed for the older adult population, do not apply to children. This review summarizes the evidence collected by the Society for Pediatric Radiology (SPR) Thoracic Imaging Committee in its attempt to develop pediatric-specific guidelines.Small pulmonary opacities can be characterized as linear or as ground-glass or solid nodules. Linear opacities and ground-glass nodules are extremely unlikely to represent an early primary or metastatic malignancy in a child. In our review, we found a virtual absence of reported cases of a primary pulmonary malignancy presenting as an incidentally detected small lung nodule on CT in a healthy immune-competent child.Because of the lack of definitive information on the clinical significance of small lung nodules that are incidentally detected on CT in children, the management of those that do not have the typical characteristics of an intrapulmonary lymph node should be dictated by the clinical history as to possible exposure to infectious agents, the presence of an occult immunodeficiency, the much higher likelihood that the nodule represents a metastasis than a primary lung tumor, and ultimately the individual preference of the child's caregiver. Nodules appearing in children with a history of immune deficiency, malignancy or congenital pulmonary airway malformation should not be considered incidental, and their workup should be dictated by the natural history of these underlying conditions.

The communication of the radiation risk from CT in relation to its clinical benefit in the era of personalized medicine: part 1: the radiation risk from CT.

The theory of radiation carcinogenesis has been debated for decades. Most estimates of the radiation risks from CT have been based on extrapolations from the lifespan follow-up study of atomic bomb survivors and on follow-up studies after therapeutic radiation, using the linear no-threshold theory. Based on this, many population-based projections of induction of future cancers by CT have been published that should not be used to estimate the risk to an individual because of their large margin of error. This has changed recently with the publication of three large international cohort follow-up studies, which link observed cancers to CT scans received in childhood. A fourth ongoing multi-country study in Europe is expected to have enough statistical power to address the limitations of the prior studies. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) report released in 2013 specifically addresses variability in response of the pediatric population exposed to ionizing radiation. Most authorities now conclude that there is enough evidence to link future cancers to the radiation exposure from a single CT scan in childhood but that cancer risk estimates for individuals must be based on the specifics of exposure, age at exposure and absorbed dose to certain tissues. Generalizations are not appropriate, and the communication of the CT risk to individuals should be conducted within the framework of personalized medicine.

The communication of the radiation risk from CT in relation to its clinical benefit in the era of personalized medicine: part 2: benefits versus risk of CT.

In order to personalize the communication of the CT risk, we need to describe the risk in the context of the clinical benefit of CT, which will generally be much higher, provided a CT scan has a well-established clinical indication. However as pediatric radiologists we should be careful not to overstate the benefit of CT, being aware that medico-legal pressures and the realities of health care economics have led to overutilization of the technology. And even though we should not use previously accumulated radiation dose to a child as an argument against conducting a clinically indicated scan (the "sunk-cost" bias), we should consider patients' radiation history in the diagnostic decision process. As a contribution to future public health, it makes more sense to look for non-radiating alternatives to CT in the much larger group of basically healthy children who are receiving occasional scans for widely prevalent conditions such as appendicitis and trauma than to attempt lowering CT use in the smaller group of patients with chronic conditions with a limited life expectancy. When communicating the CT risk with individual patients and their parents, we should acknowledge and address their concerns within the framework of informed decision-making. When appropriate, we may express the individual radiation risk, based on estimates of summated absorbed organ dose, as an order of magnitude rather than as an absolute number, and compare this with the much larger natural cancer incidence over a child's lifetime, and with other risks in medicine and daily life. We should anticipate that many patients cannot make informed decisions on their own in this complex matter, and we should offer our guidance while maintaining respect for patient autonomy. Proper documentation of the informed decision process is important for future reference. In concert with our referring physicians, pediatric radiologists are well-equipped to tackle the complexities associated with the communication of CT risk, a task that often falls upon us, and by becoming more involved in the diagnostic decision process we can add value to the health care system.

Entrance skin dosimetry and size-specific dose estimate from pediatric chest CTA.

BACKGROUND: Size-specific dose estimate (SSDE), which corrects CT dose index (CTDI) for body diameter and is a better measure of organ dose than is CTDI, has not yet been validated in vivo. OBJECTIVE: The purpose was to determine the correlation between SSDE and measured breast entrance skin dose (ESD) for pediatric chest CT angiography across a variety of techniques, scanner models, and patient sizes. METHODS: During 42 examinations done on 4 different scanners over 7 years, we measured mid-sternal ESD as an approximation of breast dose with skin dosimeters. We recorded age, weight, effective tube current, kilovoltage potential, console CTDI, and dose-length product, from which we calculated effective dose. We measured effective chest diameter to convert CTDI to SSDE, and we correlated SSDE with measured ESD, using linear regression. We evaluated image quality to answer the clinical question. RESULTS: Patient mean (±SD) age was 8.4 ± 6.1 years (median, 7.9 years; range, 0.02-19.5 years); mean weight was 35 ± 27 kg (median, 26 kg; range, 3.5-115 kg); effective chest diameter was 20 ± 7 cm (median, 19 cm; range, 10-35 cm). Mean effective dose was 2.9 ± 2.8 mSv (median, 2.2 mSv; range, 0.1-14.4 mSv). We observed a linear correlation (R(2) = 0.98, P < .005) between SSDE (mean, 11 ± 11mGy; median, 7 mGy; range, 0.5-40 mGy) and breast ESD (mean, 12 ± 11 mGy; median, 7 mGy; range, 0.3-44 mGy). Our doses, which compared favorably with those previously reported, decreased significantly (P < .05) during the course of our study, because of the introduction of automatic exposure control, low kilovoltage, and high pitch techniques. All studies were of diagnostic quality. CONCLUSION: SSDE is a valid dose measure in children undergoing chest CT angiography over a wide range of scanner platforms, techniques, and patient sizes, and it may be used to model breast dose and to document the results of dose reduction strategies.

Radiation dose reduction in pediatric cardiac computed tomography: experience from a tertiary medical center.

Cardiac CT angiography (cCTA) has become an established method for the assessment of congenital heart disease. However, the potential harmful effects of ionizing radiation must be considered, particularly in younger, more radiosensitive patients. In this study, we sought to assess the temporal change in radiation doses from pediatric cCTA during an 8-year period at a tertiary medical center. This retrospective study included all patients ≤18 years old who were referred to electrocardiography (ECG)-gated cCTA for the assessment of congenital heart disease or inflammatory disease (Kawasaki disease) from November 2004 to September 2012. During the study period, 95 patients were scanned using 3 different scanner models-64-slice multidetector CT (64-MDCT) and first- (64-DSCT) and second-generation (128-DSCT) dual-source CT-and 3 scan protocols-retrospective ECG-gated helical scanning (RG), prospective ECG-triggered axial scanning (PT), or prospective ECG-triggered high-pitch helical scanning (HPH). Effective dose (ED) was calculated with the dose length product method with a conversion factor (k) adjusted for age. ED was then compared among scan protocols. Image quality was extracted from clinical cCTA reports when available. Overall, 94 % of scans were diagnostic (80 % for 64-slice MDCT, 93 % for 64-slice DSCT, and 97 % for 128-slice DSCT).With 128-DSCT, median ED (1.0 [range 0.6-2.0] mSv) decreased by 85.8 % and 66.8 % compared with 64-MDCT (6.8 [range 2.9-13.6] mSv) and 64-DSCT (2.9 [range 0.9-4.1] mSv), respectively. With HPH, median ED (0.9 [range 0.6-1.8] mSv) decreased by 59.4 % and 85.4 % compared with PT (2.2 [range 0.9-3.4] mSv) and RG (6.1 [range 2.5-10.6] mSv). cCTA can now be obtained at very low radiation doses in pediatric patients using the latest dual-source CT technology in combination with prospective ECG-triggered HPH acquisition.

Sensenbrenner syndrome (Cranioectodermal dysplasia): clinical and molecular analyses of 39 patients including two new patients.

Sensenbrenner syndrome, also known as cranioectodermal dysplasia, is a rare multiple anomaly syndrome with distinctive craniofacial appearance, skeletal, ectodermal, connective tissue, renal, and liver anomalies. Dramatic advances with next-generation sequencing have expanded its phenotypic variability and molecular heterogeneity. We review 39 patients including two new patients, one with compound heterozygous novel mutations in WDR35 and a previously unreported multisutural craniosynostosis that may be a part of Sensenbrenner syndrome. In 14 of 25 (56.0%) patients pathogenic mutations have been identified in 4 different genes that regulate (intraflagellar) cilia transport. We compared Sensenbrenner syndrome to asphyxiating thoracic dystrophy-Jeune syndrome (ATD-JS) and other ciliopathies. Our analyses showed that the high anterior hairline, forehead bossing and dolichocephaly (accompanied by sagittal craniosynostosis in more than half of the patients) occur in almost all patients with Sensenbrenner syndrome. Metaphyseal dysplasia with narrow thorax, proximal limb shortness, and short fingers are typical of Sensenbrenner syndrome and ATD-JS. Respiratory complications have been reported in both syndromes, usually less severe with Sensenbrenner syndrome. Proposed diagnostic criteria for Sensenbrenner syndrome include the distinctive craniofacial appearance, ubiquitous brachydactyly and ectodermal anomalies, and sagittal craniosynostosis. Mild heart defects have been noted, but there have been no atrioventricular canal or heterotaxy defects that are common in Ellis-Van Creveld syndrome. We anticipate that the steady identification of molecularly defined patients may allow correlation of phenotype and genotype. Additional natural history data will improve genetic counseling and current guidelines.

Antecedents of perinatal cerebral white matter damage with and without intraventricular hemorrhage in very preterm newborns.

BACKGROUND: Isolated periventricular leukomalacia, defined as periventricular leukomalacia unaccompanied by intraventricular hemorrhage, is reportedly increased in newborns with systemic hypotension and in infants who received treatment for systemic hypotension or a patent ductus arteriosus. METHODS: This study sought to determine if the risk profile of one or more hypoechoic lesions unaccompanied by intraventricular hemorrhage, our surrogate for isolated periventricular leukomalacia, differs from that of one or more hypoechoic lesions preceded or accompanied by intraventricular hemorrhage. We compared extremely preterm infants (i.e., gestation 23-27 weeks) with each of these entities to 885 extremely preterm infants who had neither an isolated hypoechoic lesion nor a hypoechoic lesion preceded or accompanied by intraventricular hemorrhage. RESULTS: The risk of a hypoechoic lesion with intraventricular hemorrhage (N = 61) was associated with gestation <25 weeks, high Score for Acute Neonatal Physiology, early recurrent or prolonged acidemia, analgesic exposure, and mechanical ventilation 1 week after birth. CONCLUSIONS: In this large, multicenter sample of extremely low gestational age newborns, the risk profile of a hypoechoic lesion unaccompanied by intraventricular hemorrhage differed from that of a hypoechoic lesion with intraventricular hemorrhage. This suggests that hypoechoic lesions accompanied or preceded by intraventricular hemorrhage (our surrogate for periventricular hemorrhagic infarction) may have a different causal pathway than hypoechoic lesions without intraventricular hemorrhage, our surrogate for periventricular leukomalacia.

Relationship between radiologist training level and fluoroscopy time for voiding cystourethrography.

OBJECTIVE: The objective of our study was to determine whether voiding cystourethrography (VCUG) fluoroscopy time is related to the training level of the performing radiologist. MATERIALS AND METHODS: VCUG reports with normal findings from 2008 to 2011 at one institution were retrospectively reviewed. The average fluoroscopy time was calculated for first-year radiology residents, senior radiology residents, pediatric radiology fellows, and attending pediatric radiologists. The average fluoroscopy time was also calculated for radiologist sex, patient sex, and patient age group. The analysis of variance was used to evaluate differences in average fluoroscopy times between training levels of radiologists, patient age groups, and patient sexes. RESULTS: We reviewed 784 VCUG reports with normal findings: 340 (43.4%) were performed by first-year residents; 181 (23%), by senior residents; 161 (20.5%), by fellows; and 102 (13%), by attending pediatric radiologists. The overall average fluoroscopy time was 1.86 minutes (SD ± 0.98). The attending pediatric radiologists had the shortest average fluoroscopy time (1.63 ± 0.92 minutes), significantly shorter than senior residents (1.96 ± 1.09 minutes; p = 0.0070) and fellows (1.91 ± 0.85 minutes; p = 0.0255). There was no significant difference between attending radiologists and first-year residents (1.85 ± 1.00 minutes; p = 0.0550). The male-to-female ratio of radiologists was 54% versus 46%, with identical average fluoroscopy times: male radiologists, 1.86 ± 1.05 minutes; female radiologists, 1.86 ± 0.90 minutes. There was no significant difference in average fluoroscopy times among patient age groups: 1.93, 1.76, and 1.78 minutes, respectively, for groups A (0-1 years), B (> 1 to ≤ 5 years), and C (> 5 years) (p = 0.1750, 0.4605, 0.6303). The average fluoroscopy time for male patients (2.02 ± 1.00 minutes) was significantly longer than that for female patients (1.71 ± 0.95 minutes; p < 0.0001). CONCLUSION: Attending pediatric radiologists have the shortest fluoroscopy time; the differences between their average time compared with the average times of pediatric radiology fellows and of senior radiology residents were statistically significant. The average fluoroscopy time is longer for male patients than for female patients.

Radiation dose reduction with hybrid iterative reconstruction for pediatric CT.

PURPOSE: To assess image quality and radiation dose reduction with hybrid iterative reconstruction of pediatric chest and abdominal computed tomographic (CT) data compared with conventional filtered back projection (FBP). MATERIALS AND METHODS: A total of 234 patients (median age, 12 years; age range, 6 weeks to 18 years) underwent chest and abdominal CT in this institutional review board-approved HIPAA-compliant retrospective study. CT was performed with a hybrid adaptive statistical iterative reconstruction (ASIR)-enabled 64-detector row CT scanner. Scanning protocols were adjusted for clinical indication and patient weight to enable acquisition of reduced-dose CT images in all patients, and tube current was further lowered for ASIR protocols. Weight, age, and sex were recorded, and objective noise was measured in the descending thoracic aorta for chest CT and in the liver for abdominal CT. Of the 234 consecutive patients who underwent ASIR-enabled CT (115 chest and 119 abdominal examinations), 70 patients had undergone prior FBP CT. ASIR and FBP CT studies (29 chest and 41 abdominal studies) in these 70 patients were reviewed for image quality, artifacts, and diagnostic confidence by two pediatric radiologists working independently. Data were analyzed with multiple paired t tests. RESULTS: Compared with FBP, ASIR enabled dose reduction of 46.4% (3.7 vs 6.9 mGy) for chest CT and 38.2% (5.0 vs 8.1 mGy) for abdominal CT (P < .0001). Both radiologists deemed image quality of and diagnostic confidence with ASIR and FBP CT images as acceptable, without any artifacts. Despite the lower radiation dose used, ASIR images (chest, 10.7 ± 2.5 [mean ± standard deviation]; abdomen, 11.8 ± 3.4) had substantially less objective noise than did FBP images (chest, 13.3 ± 3.8; abdomen, 13.8 ± 5.2) (P = .001, P =.006, respectively). CONCLUSION: Use of a hybrid iterative reconstruction technique, such as ASIR, enables substantial radiation dose reduction for pediatric CT when compared with FBP and maintains image quality and diagnostic confidence.

Early cranial ultrasound lesions predict microcephaly at age 2 years in preterm infants.

To assess how well early ultrasound lesions in preterm newborns predict reduced head circumference at 2 years, the investigators followed 923 children born before the 28th week of gestation who were not microcephalic at birth. Six percent of children who had a normal ultrasound scan were microcephalic compared with 15% to 20% who had intraventricular hemorrhage, an echolucent lesion, or ventriculomegaly. The odds ratios (95% confidence intervals) for microcephaly associated with different ultrasound images were intraventricular hemorrhage, 1.5 (0.8-3.0); ventriculomegaly, 3.3 (1.8-6.0); an echodense lesion, 1.6 (0.7-3.5); and an echolucent lesion, 3.1 (1.5-6.2). Ventriculomegaly and an echolucent lesion had very similar low positive predictive values (24% and 27%, respectively) and high negative predictive values (91% and 90%, respectively) for microcephaly. Ventriculomegaly had a higher sensitivity for microcephaly than did an echolucent lesion (24% vs 16%, respectively). Focal white-matter lesion (echolucent lesion) and diffuse white-matter damage (ventriculomegaly) predict an increased risk of microcephaly.

Dose reduction and compliance with pediatric CT protocols adapted to patient size, clinical indication, and number of prior studies.

PURPOSE: To assess compliance and resultant radiation dose reduction with new pediatric chest and abdominal computed tomographic (CT) protocols based on patient weight, clinical indication, number of prior CT studies, and automatic exposure control. MATERIALS AND METHODS: The study was institutional review board approved and HIPAA compliant. Informed consent was waived. The new pediatric CT protocols, which were organized into six color zones based on clinical indications and number of prior CT examinations in a given patient, were retrospectively assessed. Scanning parameters were adjusted on the basis of patient weight. For gradual dose reduction, pediatric CT (n = 692) examinations were performed in three phases of incremental stepwise dose reduction during a 17-month period. There were 245 male patients and 193 female patients (mean age, 12.6 years). Two radiologists independently reviewed CT images for image quality. Data were analyzed by using multivariate analysis of variance. RESULTS: Compliance with the new protocols in the early stage of implementation (chest CT, 58.9%; abdominal CT, 65.2%) was lower than in the later stage (chest CT, 88%; abdominal CT, 82%) (P < .001). For chest CT, there was 52.6% (9.1 vs 19.2 mGy) to 85.4% (2.8 vs 19.2 mGy) dose reduction in the early stage of implementation and 73.5% (4.9 vs 18.5 mGy) to 83.2% (3.1 vs 18.5 mGy) dose reduction in the later stages compared with dose at noncompliant examinations (P < .001); there was no loss of clinically relevant image quality. For abdominal CT, there was 34.3% (9.0 vs 13.7 mGy) to 80.2% (2.7 vs 13.7 mGy) dose reduction in the early stage of implementation and 62.4% (6.5 vs 17.3) to 83.8% (2.8 vs 17.3 mGy) dose reduction in the later stage (P < .001). CONCLUSION: Substantial dose reduction and high compliance can be obtained with pediatric CT protocols tailored to clinical indications, patient weight, and number of prior studies.

The imaging of paediatric thoracic trauma.

Major chest trauma in a child is associated with significant morbidity and mortality. It is most frequently encountered within the context of multisystem injury following high-energy trauma such as a motor vehicle accident. The anatomic-physiologic make-up of children is such that the pattern of ensuing injuries differs from that in their adult counterparts. Pulmonary contusion, pneumothorax, haemothorax and rib fractures are most commonly encountered. Although clinically more serious and potentially life threatening, tracheobronchial tear, aortic rupture and cardiac injuries are seldom observed. The most appropriate imaging algorithm is one tailored to the individual child and is guided by the nature of the traumatic event as well as clinical parameters. Chest radiography remains the first and most important imaging tool in paediatric chest trauma and should be supplemented with US and CT as indicated. Multidetector CT allows for the accurate diagnosis of most traumatic injuries, but should be only used in selected cases as its routine use in all paediatric patients would result in an unacceptably high radiation exposure to a large number of patients without proven clinical benefit. When CT is used, appropriate modifications should be incorporated so as to minimize the radiation dose to the patient whilst preserving diagnostic integrity.