High-field MR imaging in pediatric congenital heart disease: initial results.

BACKGROUND: Comprehensive assessment of pediatric congenital heart disease (CHD) at any field strength mandates evaluation of both vascular and dynamic cardiac anatomy for which diagnostic quality contrast-enhanced magnetic resonance angiography (CEMRA) and cardiac cine are crucial. OBJECTIVE: To determine whether high-resolution (HR) CEMRA and steady-state free precession (SSFP) cine can be performed reliably at 3.0 T in children with CHD and to compare the image quality to similar techniques performed at 1.5 T. MATERIALS AND METHODS: Twenty-eight patients with a median age of 5 months and average weight 9.0 ± 7.8 kg with suspected or known CHD were evaluated at 3.0 T. SSFP cine (n = 86 series) and HR-CEMRA (n = 414 named vascular segments) were performed and images were scored for image quality and artifacts. The findings were compared to those of 28 patients with CHD of similar weight who were evaluated at 1.5 T. RESULTS: Overall image quality on HR-CEMRA was rated as excellent or good in 96% (397/414) of vascular segments at 3.0 T (k = 0.49) and in 94% (349/371) of vascular segments at 1.5 T (k = 0.36). Overall image quality of SSFP was rated excellent or good in 91% (78/86) of cine series at 3.0 T (k = 0.55) and in 81% (87/108) at 1.5 T (k = 0.47). Off-resonance artifact was common at both field strengths, varied over the cardiac cycle and was more prevalent at 3.0 T. At 3.0 T, off-resonance dark band artifact on SSFP cine was absent in 3% (3/86), mild in 69% (59/86), moderate in 27% (23/86) and severe in 1% (1/86) of images; at 1.5 T, dark band artifact was absent in 16% (17/108), mild in 69% (75/108), moderate in 12% (13/108) and severe in 3% (3/108) of cine images. The signal-to-noise ratio and contrast-to-noise ratio of both SSFP cine and HR-CEMRA images were significantly higher at 3.0 T than at 1.5 T (P < 0.001). CONCLUSION: Signal-to-noise ratio and contrast-to-noise ratio of high-resolution contrast-enhanced magnetic resonance angiography and SSFP cine were higher at 3.0 T than at 1.5 T. Artifacts on SSFP cine were cardiac phase specific and more prevalent at 3.0 T such that frequency-tuning was required in one-third of exams. In neonates, high spatial resolution CEMRA was highly reliable in defining extracardiac vascular anatomy.

Osteochondral lesions in pediatric and adolescent patients.

Osteochondral lesions are acquired, potentially reversible injuries of the subchondral bone with or without associated articular cartilage involvement. Injury results in delamination and potential sequestration of the affected bone. Although an association with mechanical and traumatic factors has been established, the etiology remains poorly understood. These lesions commonly occur in the knee; articular surfaces of the elbow, ankle, hip, and shoulder are also affected. Osteochondral lesions are relatively common in children and adolescents, and the incidence is increasing. Prognosis of these lesions depends on stability, location, and size of the lesion.Imaging has an essential role in the diagnosis, staging, and management of osteochondral lesions. Many of these lesions are first diagnosed by plain film. MRI adds value by identifying unstable lesions that require surgical intervention. This review focuses on the clinical and imaging features of osteochondral lesions of the knee, elbow, and ankle. Imaging criteria for staging and management are also reviewed.

Immune dysregulation after cardiothoracic surgery and incidental thymectomy: maintenance of regulatory T cells despite impaired thymopoiesis.

Thymectomy is performed in infants during cardiothoracic surgery leaving many patients with reduced thympopoiesis. An association between immune disorders and regulatory T cells (Treg) after incidental thymectomy has not been investigated. Questionnaires soliciting symptoms of atopic or autoimmune disease and biomarkers were measured in children and adults with congenital heart disease and either reduced or preserved thymopoiesis. Tregs were examined. Atopic or autoimmune-like symptoms and elevated anti-dsDNA antibodies were common after surgery in individuals with low thymopoiesis. Total Treg number and function were maintained but with fewer naïve Treg. TCR spectratypes were similar to other memory T cells. These data suggest that thymectomy does not reduce total Treg number but homeostasis is affected with reduced naïve Treg. Prevalence of autoimmune or atopic symptoms after surgery is not associated with total number or proportion of Tregs but appears to be due to otherwise unknown factors that may include altered Treg homeostasis.

Women in pediatric radiology.

Women represent a significant proportion of pediatric radiologists in the United States, as shown on surveys by the American College of Radiology (ACR) and the Society for Pediatric Radiology (SPR). This review discusses the characteristics of this subgroup of specialists and issues uniquely related to them.

Estimated cumulative radiation dose from PET/CT in children with malignancies: a 5-year retrospective review.

BACKGROUND: The increasing use of serial PET/CT scans in the management of pediatric malignancies raises the important consideration of radiation exposure in children. OBJECTIVE: To estimate the cumulative radiation dose from PET/CT studies to children with malignancy and to compare with the data in literature. MATERIALS AND METHODS: Two hundred forty-eight clinical PET/CT studies performed on 78 patients (50 boys/28 girls, 1.3 to 18 years old from December 2002 to October 2007) were retrospectively reviewed under IRB approval. The whole-body effective dose (ED) estimates for each child were obtained by estimating the effective dose from each PET/CT exam performed using the ImPACT Patient Dosimetry Calculator for CT and OLINDA for PET. RESULTS: The average number of PET/CT studies was 3.2 per child (range: 1 to 14 studies). The average ED of an individual CT study was 20.3 mSv (range: 2.7 to 54.2), of PET study was 4.6 mSv (range: 0.4 to 7.7) and of PET/CT study was 24.8 mSv (range: 6.2 to 60.7). The average cumulative radiation dose per patient from CT studies was 64.4 mSv (range: 2.7 to 326), from PET studies was 14.5 mSv (range: 2.8 to 73) and from PET/CT studies was 78.9 mSv (range: 6.2 to 399). CONCLUSION: The radiation exposure from serial PET/CT studies performed in pediatric malignancies was considerable; however, lower doses can be used for both PET and CT studies. The ALARA principle must be applied without sacrificing diagnostic information.

Association Between Neonatal Neuroimaging and Clinical Outcomes in Zika-Exposed Infants From Rio de Janeiro, Brazil.

Importance: Congenital Zika virus (ZIKV) infection may present with a spectrum of clinical and neuroradiographic findings. Objective: To determine whether neuroimaging findings for infants with a history of ZIKV exposure are associated with infant clinical outcomes and gestational age at antenatal ZIKV infection. Design, Setting, and Participants: This cohort study retrospectively reviewed neuroimaging results (computed tomography and/or magnetic resonance imaging scans) of 110 ZIKV-exposed infants from a maternity and children's hospital in Rio de Janeiro, Brazil, following the 2015 to 2016 ZIKV epidemic. Neuroimaging from March 1, 2016, to June 30, 2017, was evaluated to determine whether findings were associated with clinical outcomes and the timing of maternal ZIKV infection. Data were analyzed from July 1, 2017, to August 30, 2018. Exposures: Neuroimaging (computed tomography and/or magnetic resonance imaging) was performed on ZIKV-exposed infants after birth. Blood and/or urine specimens from mothers and infants were tested for ZIKV by polymerase chain reaction assay. Main Outcomes and Measures: Neuroimaging studies were evaluated for structural abnormalities and other forms of brain injury. Results: A total of 110 infants with a mean (SD) gestational age of 38.4 (2.1) weeks had neuroimaging and clinical outcome data reviewed. Of these, 71 (65%) had abnormal neuroimaging findings, with the majority (96%) classified as having severe ZIKV infection at birth. The most common neuroimaging abnormalities were structural abnormalities including brain calcifications, especially at the cortico-subcortical white matter junction, cortex malformations, ventriculomegaly, and reduced brain volumes, followed by brainstem hypoplasia, cerebellar hypoplasia, and corpus callosum abnormalities. Frequency of abnormal imaging was higher in infants with specific clinical findings as opposed to those without them; these findings included fetal brain disruption sequence (100% vs 35%), microcephaly (100% vs 30%), congenital contractures (100% vs 58%), ophthalmologic abnormalities (95% vs 44%), hearing abnormalities (100% vs 58%), and neurologic symptoms (94% vs 10%). Four of 39 infants (10%) without initial evidence of severe ZIKV infection and normal findings on neurologic evaluation at birth had abnormal neuroimaging findings. Neuroimaging abnormalities differed by trimester of maternal ZIKV infection, with 63% of infants born to mothers infected in the first trimester, 13% of infants born to mothers infected in the second trimester, and 1% of infants born to mothers infected in the third trimester exhibiting neuroimaging abnormalities. The odds of abnormal neuroimaging were 7.9 times greater for infants with first trimester ZIKV exposure compared with other trimesters combined (odds ratio, 7.9; 95% CI, 3.0-20.4; P < .001). Conclusions and Relevance: Neuroimaging abnormalities of computed tomography and/or magnetic resonance imaging scans were common in ZIKV-exposed infants. While neuroimaging abnormalities were seen in 10% of infants without clinically severe ZIKV, most occurred almost exclusively among those with clinically severe ZIKV, especially among those with a history of ZIKV exposure in the first trimester.

Graphic representation of skeletal maturity determinations.

OBJECTIVE: Skeletal maturation determinations are usually reported as numeric data indicating accordance with chronologic age. However, significant changes in skeletal maturation can occur without falling outside two SDs. The purpose of our study was to design simple computer-generated sex-based charts to enhance the evaluation of skeletal maturation, especially when frequent assessments are made. CONCLUSION: The graphic representation of successive reports clearly depicts whether values retain their position in relation to the mean. In addition, the report includes computation of the exact SD score.

Osteomalacia in a hemodialysis patient receiving an active vitamin D sterol.

BACKGROUND: A 17-year-old Filipino male hemodialysis patient presented for renal transplant evaluation. He had significant skeletal abnormalities characterized by bone pain, an inability to walk, and secondary hyperparathyroidism despite therapy with an active vitamin D sterol (paricalcitol). INVESTIGATIONS: The patient underwent a physical examination, and his serum levels of calcium, phosphorus, alkaline phosphatase, parathyroid hormone, aluminum and 25-hydroxycholecalciferol (25OH-vitamin D) were determined. X-rays of hips and lower extremities, MRI, and bone histomorphometry after double tetracycline labeling were performed. DIAGNOSIS: Osteomalacia associated with low 25OH-vitamin D levels. MANAGEMENT: Monthly therapy with ergocalciferol (vitamin D2) and discontinuation of paricalcitol.

Cardiac MR imaging and MR angiography for assessment of complex tetralogy of Fallot and pulmonary atresia.

Breath-hold electrocardiographically gated cardiac magnetic resonance (MR) imaging and contrast material-enhanced MR angiography are emerging as ideal techniques for the evaluation of complex congenital heart disease. Tetralogy of Fallot is the most common cause of cyanotic congenital heart disease and, in its classic form, is associated with varying degrees of hypoplasia of the central and peripheral pulmonary arteries, with valvar pulmonary atresia and collateral aortopulmonary vessels occupying the extreme end of the spectrum. Accurate assessment of the size and anatomy of the pulmonary arteries is often difficult with echocardiography and conventional cineangiography. Compared with echocardiography in particular, cardiac MR imaging with three-dimensional reconstruction has distinct advantages for pre- or postoperative assessment of pulmonary anatomy in patients with tetralogy of Fallot and pulmonary atresia. MR imaging enables the clear and complete depiction of anatomy and thus can provide additional information about pulmonary artery abnormalities that are difficult to evaluate with conventional cardiac imaging techniques.

Contrast-enhanced MR angiography of the chest and abdomen with use of controlled apnea in children.

PURPOSE: To retrospectively determine if controlled apnea improves the image quality of contrast material--enhanced magnetic resonance (MR) angiography of the chest and abdomen in children. MATERIALS AND METHODS: Institutional review board approval and waiver of informed consent were obtained for this HIPAA-compliant study. The authors evaluated contrast-enhanced MR angiographic procedures performed in the chest, abdomen, or both, in 23 children (14 boys, nine girls; age range, 1 month to 8 years) who were under general anesthesia. All patients underwent mechanical ventilation with preoxygenation (100% oxygen) prior to controlled apnea during image acquisition. In control subjects, the authors assessed contrast-enhanced MR angiographic procedures performed in the chest, abdomen, or both, in 23 children (matched for age and type of study with children in the controlled apnea group; 11 boys, 12 girls; age range, 1 month to 8 years) who were under general anesthesia (n=15) or deep sedation (n=8) and were breathing spontaneously during image acquisition. MR angiograms of the chest, abdomen, or both, were assessed for image quality, motion artifacts, and vessel definition by two radiologists working in consensus with a subjective grading scale. Wilcoxon signed rank test was used to assess differences in measurements. RESULTS: Image quality was rated excellent in 97% (30 of 31) of studies with controlled apnea and in 30% (nine of 31) of control studies (P<.001). Motion artifacts were absent in 97% (30 of 31) of studies with controlled apnea and 13% (four of 31) of control studies (P<.001). Vessel sharpness was rated as being significantly better on images obtained with controlled apnea (P<.05). There were no complications caused by anesthesia or sedation in either group. CONCLUSION: Controlled apnea is highly effective in children for eliminating respiratory motion artifacts with contrast-enhanced MR angiographic studies, resulting in greatly improved image quality and spatial resolution.

Idiopathic infantile arterial calcification: imaging evaluation and the usefulness of MR angiography.

Idiopathic infantile arterial calcification (IIAC) is a rare condition characterized by extensive calcification and stenosis of large and medium-size arteries. The etiology of the disease is unknown. However, the inheritance pattern has been shown to be autosomal recessive. The clinical presentation is variable, including cardiac failure (most common clinical finding), hypertension, and respiratory failure. Plain radiography, sonography and MRI can aid in the diagnosis. We present a case in which contrast-enhanced MR angiography with breath-hold and cardiac gating techniques allowed complete evaluation of the extent of this disease.

Radiographic appearance of pediatric cardiovascular transcatheter devices.

The treatment of congenital heart disease has been revolutionized by the availability of transcatheter devices. These advances in interventional pediatric cardiology require that both treating physicians and radiologists develop a more thorough understanding of the appearance of these devices on chest radiographs. Furthermore, recognition of appropriate versus inappropriate placement of transcatheter devices is essential to the care of patients with congenital heart disease. Knowledge of the radiographic appearance of devices used by interventional pediatric cardiologists can allow a radiologist to make better clinical assessments and detect possible complications given a limited clinical history.

Parasitic omphalopagus complicated by omphalocele and congenital heart disease.

Conjoined twins occur in approximately one of every 50,000 to 200,000 births. Atypical or parasitic conjoined twins result from the embryonic death of one twin, which leaves behind body parts vascularized by the primary twin. Omphalopagus refers to conjoined twins joined at the level of the umbilicus. The authors report a case of atypical omphalopagus involving an acardiac, acephalic, parasitic twin and a host twin with a large omphalocele, transposition of the great arteries, and aortic coarctation. The authors briefly review reported cases of parasitic omphalopagus and emphasize the role of intensive neonatal care, preoperative planning, and staged surgical intervention in the successful management of complicated variants.