Cardiovascular flow is commonly assessed with two-dimensional, phase contrast (2D PC-MRI). However, scan prescription and acquisition over multiple planes is lengthy, often requires direct physician oversight, and has inconsistent results. Time-resolved volumetric PC-MRI (4D flow) may address these limitations.
We assess the degree of agreement and internal consistency between 2D and 4D flow quantification in our clinical population.
Software enabling flow calculation from 4D flow was developed in Java. With IRB approval and HIPAA compliance, eighteen consecutive patients without shunts were identified who underwent both (a) conventional 2D PC-MRI of the aorta and main pulmonary artery and (b) 4D flow imaging. Aortic and pulmonary flow rates were assessed with both techniques.
Both methods showed general agreement in flow rates (ρ: 0.87-0.90). Systemic and pulmonary arterial flow rates were well-correlated (ρ: 4D 0.98-0.99, 2D 0.93), but more closely matched with 4D (p<0.05, Brown-Forsythe). Pulmonary flow rates were lower than systemic rates for 2D (p<0.05, two-sample t-test). In a sub-analysis of patients without pulmonary or aortic regurgitation, 2D showed improved correlation of flow rates while 4D phase-contrast remained tightly correlated (ρ: 4D 0.99-1.00, 2D 0.99).
4D PC-MRI demonstrates greater consistency than conventional 2D PC-MRI for flow quantification.
blood flow; magnetic resonance imaging; imaging
Optic pathway gliomas (OPGs) are common pediatric brain tumors that pose significant clinical challenges with regard to predicting which tumors are likely to become symptomatic and require treatment. These tumors can arise sporadically or in the context of the inherited cancer predisposition syndrome, Neurofibromatosis type 1 (NF1). Few studies have suggested biological or imaging markers which predict the clinical course of this disease.
In this cross-sectional study, we hypothesize that the clinical behavior of OPGs in children can be differentiated by diffusion-weighted (DWI) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI).
27 patients with OPG were studied using DWI and DCE MRI protocols. Diffusivity and permeability were calculated and correlated to OPG clinical behavior.
Mean diffusivity values of 1.39 μm2/ms and mean permeability values of 2.10 ml min−1 per 100 cc of tissue were measured. “Clinically-aggressive” OPGs had significantly higher mean permeability values (P=.05) than “clinically stable” tumors. In addition, there was a strong correlation between clinical aggressiveness and the absence of NF1 (P < 0.01).
These results suggest that DCE might be a useful biomarker for “clinically aggressive” OPG, which should be confirmed in larger prospective longitudinal studies.
Previous studies suggest that semicircular canal dehiscences (SCDs) have a developmental origin.
We hypothesized that if SCDs originate during development, incidence of radiographic SCDs in young children will be higher than in adults.
Materials and methods
Thirty-four temporal bone HRCTs of children younger than 2 years and 40 temporal bone HRCTs of patients older than 18 years were reformatted and re-evaluated for presence of SCD or canal thinning. Results were compared with indications for HRCT and clinical information.
SCDs were detected in 27.3% of children younger than 2 years of age (superior, 13.8%; posterior, 20%) and in 3% of adults (P≤0.004). Of children with one radiographic dehiscence, 55.6% had multiple and 44% had bilateral SCDs on HRCT. No lateral canal SCDs were present. Thinning of bone overlying the semicircular canals was found in 44% of children younger than 2 years and 2.5% of adults (P<0.0001).
SCDs are more common on HRCTs of very young children. This supports the hypothesis that SCDs originate from discontinuation of bone deposition/maturation. However, SCDs on imaging do not necessarily correlate with canal dehiscence syndrome and should therefore be interpreted carefully.
Superior semicircular canal dehiscence; Posterior semicircular canal dehiscence; Semicircular canal dehiscence syndrome; High-resolution CT; Pediatric
Eosinophilic colitis (EC) is a gastrointestinal disease of undetermined etiology whose clinical features overlap with those of the inflammatory bowel diseases. To the best of our knowledge, the CT imaging features of EC have not been described in children.
To report and analyze the clinical, imaging and histological findings in seven children with EC.
Materials and methods
Children with EC were identified in a pediatric pathology database, and those with CT imaging within 2 months of diagnosis were included, totaling seven children. Clinical, imaging and pathological features were reviewed and analyzed.
The most common presenting symptoms were abdominal pain, bloody diarrhea and rectal bleeding. EC was characterized as a dense and predominantly eosinophilic inflammatory infiltrate in the lamina propria or epithelium without granulomas. CT scans were abnormal in six children (86%), demonstrating colonic wall thickening, predominantly cecal, in five (71%), mild to moderate terminal ileal thickening in two (29%), and pneumatosis in one (14%). Right colonic involvement was greater than terminal ileal involvement.
CT imaging findings in children with EC include right colonic wall thickening of variable extent downstream and absent or mild involvement of the terminal ileum. EC should be considered in the differential diagnosis in children presenting with abdominal pain and bloody diarrhea.
Eosinophilic; Colitis; CT; Inflammatory bowel disease; Allergy; Eosinophilic gastrointestinal disease; Children
Contrast-enhanced cardiac MRA suffers from cardiac motion artifacts and often requires a breath-hold.
This work develops and evaluates a blood pool contrast agent enhanced combined respiratory and ECG triggered MRA method.
Materials and methods
An SPGR sequence was modified to enable combined cardiac and respiratory triggering on a 1.5T scanner. 23 consecutive patients referred for pediatric heart disease receiving gadofosveset were recruited in HIPAA-compliant fashion with IRB approval and informed consent/assent. Patients underwent standard, non-triggered contrast-enhanced MRA with or without suspended respiration. Additionally, a free-breathing triggered MRA was acquired. Triggered and non-triggered studies were presented in blinded random order independently to two radiologists twice. Anatomic structure delineation was graded for each triggered and non-triggered acquisition and the visual quality on triggered MRA was compared directly to non-triggered MRA.
Triggered images received higher scores from each radiologist for all anatomic structures on each of the two reading sessions (Wilcoxon rank-sum test, p< 0.05). In direct comparison, triggered images were preferred over non-triggered images for delineating cardiac structures, with most comparisons reaching statistical significance (binomial test, p<0.05).
Combined cardiac and respiratory triggering, enabled by a blood-pool contrast agent, improves delineation of most anatomic structures in pediatric cardiovascular MRA.
Diffusion tensor imaging (DTI) is an MRI technique that can measure the macroscopic structural organization in brain tissues. DTI has been shown to provide information complementary to relaxation-based MRI about the changes in the brain's microstructure. In the pediatric population, DTI enables quantitative observation of the maturation process of white matter structures. Its ability to delineate various brain structures during developmental stages makes it an effective tool with which to characterize both the normal and abnormal anatomy of the developing brain. This review will highlight the advantages, as well as the common technical pitfalls of pediatric DTI. In addition, image quantification strategies for various DTI-derived parameters and the normal brain developmental changes associated with these parameters are discussed.
Diffusion tensor imaging (DTI); MRI; Normal development
Melanotic neuroectodermal tumour of infancy (MNTI) is a rare neoplasm of neural crest origin. It is benign but locally aggressive and tends to occur most often during the first few months of life. It has a predilection for the head and neck region, particularly for the maxilla. Presence of melanin in this tumour is said to give it distinct clinicopathological, immunohistochemical, ultrastructural and imaging features . We describe five further cases of MNTI, with an emphasis on computed tomography (CT) and magnetic resonance (MR) imaging findings, which have yet to be clearly described in the available radiological literature for this tumour.
We review our experience with unusual ocular pathologies mimicking retinoblastoma that were referred to our institution over the past two decades. After presenting the imaging anatomy of the normal eye, we discuss pertinent clinical and pathological features, and illustrate the ultrasound and magnetic resonance imaging appearance of retinoblastoma, medulloepithelioma, uveal melanoma, persistent fetal vasculature, Coats disease, corneal dermoid, retinal dysplasia and toxocara granuloma. Features useful in discriminating between these entities are emphasized.
MR elastography is one of the only non-invasive techniques that can accurately and reliably identify and stage liver fibrosis. Importantly, it has been shown to more effectively stage liver fibrosis in adults than other non-invasive assessments and thus can be used to follow treatment response or disease progression. The mechanical properties of liver tissue appear to be the same for adults and children suggesting MRE will prove to be an accurate non-invasive test for identifying, staging and tracking liver fibrosis. In our experience it is technically feasible for pediatric patients, even in young infants. MRE findings appear to correlate well with liver biopsy results in the small number of patients where we have pathologic correlation but larger, studies will be needed to confirm the reliability and accuracy of this technique to establish it as an alternative to pediatric liver biopsy.
Pneumatosis intestinalis in children is associated with a wide variety of underlying conditions and often has a benign course. The computed tomography features of this condition have not been systematically investigated.
Defining benign pneumatosis intestinalis as cases that resolved with medical management alone, we sought to: 1) determine whether the incidence of benign pneumatosis intestinalis had increased at our pediatric cancer hospital, 2) characterize computed tomography features of benign pneumatosis intestinalis, and 3) determine the relation between imaging features and clinical course of benign pneumatosis intestinalis in this cohort.
Materials and Methods
Radiology reports from November 1994 to December 2006 were searched for “pneumatosis intestinalis,” “free intraperitoneal air,” and “portal venous air or gas.” Corresponding imaging was reviewed by two radiologists who confirmed pneumatosis intestinalis, recorded presence of extraluminal free air, degree of intramural gaseous distension, number of involved bowel segments, and time to pneumatosis resolution.
Twelve boys and 4 girls had pneumatosis intestinalis; 11 were hematopoietic stem cell transplant recipients. Annual incidences of benign pneumatosis have not changed at our institution. Increases in intramural distension marginally correlated with increases in bowel segments involved (P=0.08). Three patients had free air and longer times to resolution of pneumatosis (P=0.03).
Male children may be at increased risk for benign pneumatosis intestinalis. The incidence of benign pneumatosis at our institution is proportional to number of hematopoietic stem cell transplants. Degree of intramural distension may correlate with number of bowel segments involved. Patients with free air have a longer time to resolution of benign pneumatosis.
A rapid, reliable radiation-free method of pediatric body venography may complement ultrasound by evaluating veins in the abdomen and pelvis, as well as providing a global depiction of venous anatomy. We describe a MR venography technique utilizing gadofosveset, a blood pool contrast agent, in pediatric patients. The technique allows high-spatial-resolution imaging of the veins from the diaphragm to the knees in less than 15 minutes of total exam time.
venography; MRI; gadofosveset; blood pool contrast agent
Use of PET/MR in children has not previously been reported, to the best of our knowledge. Children with systemic malignancies may benefit from the reduced radiation exposure offered by PET/MR. We report our initial experience with PET/MR hybrid imaging and our current established sequence protocol after 21 PET/MR studies in 15 children with multifocal malignant diseases. The effective dose of a PET/MR scan was only about 20% that of the equivalent PET/CT examination. Simultaneous acquisition of PET and MR data combines the advantages of the two previously separate modalities. Furthermore, the technique also enables whole-body diffusion-weighted imaging (DWI) and statements to be made about the biological cellularity and nuclear/cytoplasmic ratio of tumours. Combined PET/MR saves time and resources. One disadvantage of PET/MR is that in order to have an effect, a significantly longer examination time is needed than with PET/CT. In our initial experience, PET/MR has turned out to be an unexpectedly stable and reliable hybrid imaging modality, which generates a complementary diagnostic study of great additional value.
Children; PET/MR; MR/PET; Oncology; Hybrid imaging
MRI potentially offers an alternative to CT, and thus is central to an ALARA strategy. However, long exam times, limited magnet availability, and motion artifacts are barriers to expanded use of MRI. This article reviews developments in pediatric body MRI that may reduce these barriers: high field systems, acceleration, navigation, and newer contrast agents.
Menkes disease is an X-linked recessive disorder of copper transport caused by mutations in ATP7A, a copper-transporting ATPase. Certain radiologic findings reported in this condition overlap with those caused by child abuse. However, cervical spine defects simulating cervical spine fracture, a known result of nonaccidental pediatric trauma, have not been reported previously in this illness.
To assess the frequency of cervical spine anomalies in Menkes disease after discovery of an apparent C2 posterior arch defect in a child participating in a clinical trial.
Materials and methods
We examined cervical spine radiographs obtained in 35 children with Menkes disease enrolled in a clinical trial at the National Institutes of Health Clinical Center.
Four of the 35 children with Menkes disease had apparent C2 posterior arch defects consistent with spondylolysis or incomplete/delayed ossification.
Defects in C2 were found in 11% of infants and young children with Menkes disease. Discovery of cervical spine defects expands the spectrum of radiologic findings associated with this condition. As with other skeletal abnormalities, this feature simulates nonaccidental trauma. In the context of Menkes disease, suspicions of child abuse should be considered cautiously and tempered by these findings to avoid unwarranted accusations.
Menkes disease; Cervical spine; Bone abnormalities; Copper metabolism
Cerebral MRI performed on preterm infants at term-equivalent 30 weeks' gestational age (GA) is increasingly performed as part of standard clinical care.
We evaluated safety of these early MRI procedures.
Materials and methods
We retrospectively collected data on patient safety of preterm infants who underwent early MRI scans. Data were collected at fixed times before and after the MRI scan. MRI procedures were carried out according to a comprehensive guideline.
A total of 52 infants underwent an MRI scan at 30 weeks’ GA. Although no serious adverse events occurred and vital parameters remained stable during the procedure, minor adverse events were encountered in 26 infants (50%). The MRI was terminated in three infants (5.8%) because of respiratory instability. Increased respiratory support within 24 h after the MRI was necessary for 12 infants (23.1%) and was significantly associated with GA, birth weight and the mode of respiratory support. Hypothermia (core temperature < 36°C) occurred in nine infants (17.3%). Temperature dropped significantly after the MRI scan.
Minor adverse events after MRI procedures at 30 weeks GA were common and should not be underestimated. A dedicated and comprehensive guideline for MRI procedures in preterm infants is essential.
Electronic supplementary material
The online version of this article (doi:10.1007/s00247-012-2426-y) contains supplementary material, which is available to authorized users.
Premature infants; MRI; Safety management
Little information exists regarding pediatric contrast enhanced ultrasonography.
To assess the safety and feasibility of contrast enhanced ultrasonography of pediatric abdominal and pelvic tumors.
Materials and Methods
This prospective study included eight boys and five girls (mean age, 10.8 years) with abdominal or pelvic tumors. Cohorts of three subjects underwent ultrasound with perflutren contrast agent at escalating dose levels.Neurological and funduscopic examination, electrocardiography, and continuous pulse oximetry were performed before and after contrast administration. Threeradiologists independently scored six imaging parameters on pre- and post-contrast sonography. Inter-reviewer agreement was measured by the Kappa statistic.
No neurological, retinal, electrocardiographic, or pulse oximetry changes were attributable to the contrast agent. Two subjects reported minor, transient symptoms. Post-contrast ultrasound parameter scores improved slightly in 8 of 12 subjects. Post-contrast ultrasound inter-reviewer agreement improved slightly for detection of tumor margins (pre-contrast = 0.20, post-contrast = 0.26), local tumor invasion (pre-contrast = −0.01, post-contrast = 0.10) and adenopathy (pre-contrast = 0.35, post-contrast = 0.44).
Although our sample size is small, perflutren contrast agents appear to be safe and well tolerated in children. Contrast enhanced sonography of pediatric abdominal and pelvic tumors is feasible but larger studies are needed to define their safety and efficacy in this patient population.
safety; feasibility; contrast enhanced ultrasound; pediatric solid malignancies
A number of radiogrammetrical metacarpal indices are in use, some of which have been adapted for children.
The purpose of this study was to compare four known indices—bone mineral density (BMD), relative cortical area, Exton-Smith index, bending breaking resistance index—and the more recently defined pediatric bone index (PBI) according to the two criteria of minimum height dependence and minimum variability in children of equal bone age.
Materials and methods
A total of 3,121 left-hand radiographs from 231 healthy Caucasian children ranging in age from 3 to 19 years old were analysed using BoneXpert®, a programme for automatic analysis of hand radiographs and assessment of bone age.
Dependence on height for chronological age or bone age and the mean relative standard deviation were lowest in the PBI for both genders pooled. The differences in height dependence were statistically significant and are shown to be clinically relevant. Reference data for PBI are presented.
PBI may be a better indicator than BMD for bone health in children; however, verification in a clinical group is needed.
Radiogrammetry; Densitometry; Metacarpal dimensions; Skeletal growth; Child; Reference values
During surgery for spinal deformities, accurate placement of pedicle screws may be guided by intraoperative cone-beam flat-detector CT.
The purpose of this study was to identify appropriate paediatric imaging protocols aiming to reduce the radiation dose in line with the ALARA principle.
Materials and methods
Using O-arm® (Medtronic, Inc.), three paediatric phantoms were employed to measure CTDIw doses with default and lowered exposure settings. Images from 126 scans were evaluated by two spinal surgeons and scores were compared (Kappa statistics). Effective doses were calculated. The recommended new low-dose 3-D spine protocols were then used in 15 children.
The lowest acceptable exposure as judged by image quality for intraoperative use was 70 kVp/40 mAs, 70 kVp/80 mAs and 80 kVp/40 mAs for the 1-, 5- and 12-year-old-equivalent phantoms respectively (kappa = 0,70). Optimised dose settings reduced CTDIw doses 89–93%. The effective dose was 0.5 mSv (91–94,5% reduction). The optimised protocols were used clinically without problems.
Radiation doses for intraoperative 3-D CT using a cone-beam flat-detector scanner could be reduced at least 89% compared to manufacturer settings and still be used to safely navigate pedicle screws.
O-arm; Paediatric spine; Preoperative CT scan; Radiation dose
A mother’s circulating estrogen increases over the third trimester, producing physiological effects on her newborn that wane postnatally. Estrogenization might be prolonged in newborns exposed to exogenous estrogens, such as isoflavones in soy formula.
We evaluated ultrasonography for monitoring growth of multiple estrogen-responsive organs in healthy infants and developed organ-growth trajectories.
Materials and methods
We studied 38 boys (61 visits) from birth to age 6 months and 41 girls (96 visits) from birth to age 1 year using a partly cross-sectional, partly longitudinal design. We measured uterus and ovaries in girls, testes and prostate in boys, and kidneys, breasts, thymus, and thyroid in all children. We imaged all organs from the body surface in one session of < 1 h.
Uterine volume decreased from birth (P<0.0001), whereas ovarian volume increased sharply until age 2 months and then decreased (P<0.001). Testicular volume increased with age (P<0.0001), but prostatic volume showed minimal age trend. Breast bud diameter showed no age trend in girls but declined from birth in boys (P=0.03).
US examination of multiple estrogen-responsive organs in infants in a single session is feasible and yields volume estimates useful for assessing potential endocrine disruptor effects on organ growth.
US; Infant; Organ growth; Soy formula; Ultrasongraphy
Until now, brain magnetic resonance imaging (MRIs) in asphyxiated neonates receiving therapeutic hypothermia have been performed after treatment is complete. However, there is increasing interest in early brain MRI while hypothermia is still being provided, in order to rapidly understand the degree of brain injury and possibly refine neuroprotective strategies. This study was designed to assess whether therapeutic hypothermia can be maintained while performing a brain MRI. Twenty MRI scans were obtained in twelve asphyxiated neonates while they were treated with hypothermia. Median difference between esophageal temperature on NICU departure and return was 0.1°C (range: −0.8 to 0.8°C). In conclusion, therapeutic hypothermia can be safely and reproducibly maintained during a brain MRI. Hypothermia treatment should not prevent obtaining an early brain MRI if clinically indicated.
hypoxic-ischemic encephalopathy; newborn; perinatal asphyxia; hypothermia; magnetic resonance imaging
Adrenal abscess is an uncommon finding in neonates and young infants. It may have a fatal outcome if inadequately treated. This case report describes the successful diagnosis and treatment of a left-sided adrenal abscess in a 5-week-old girl. Abdominal US and antigranulocyte antibody-scintigraphy showed an encapsulated suprarenal mass with debris suspicious for an adrenal abscess. Treatment is generally surgical. In this case, however, we performed US-guided percutaneous drainage combined with intravenous antibiotic treatment. The child recovered fully.
Neonate; Adrenal abscess; Ultrasound; Scintigraphy
Children with severe neurological impairment and intellectual disability (ID) are susceptible for developing low bone mineral density (BMD) and fractures. BMD is generally measured with dual-energy X-ray absorptiometry (DXA).
To describe the occurrence of factors that may influence the feasibility of DXA and the accuracy of DXA outcome in children with severe neurological impairment and ID.
Materials and methods
Based on literature and expert opinion, a list of disrupting factors was developed. Occurrence of these factors was assessed in 27 children who underwent DXA measurement.
Disrupting factors that occurred most frequently were movement during measurement (82%), aberrant body composition (67%), small length for age (56%) and scoliosis (37%). The number of disrupting factors per child was mean 5.3 (range 1–8). No correlation was found between DXA outcomes and the number of disrupting factors.
Factors that may negatively influence the accuracy of DXA outcome are frequently present in children with severe neurological impairment and ID. No systematic deviation of DXA outcome in coherence with the amount of disrupting factors was found, but physicians should be aware of the possible influence of disrupting factors on the accuracy of DXA.
Dual-energy X-ray absorptiometry; Severe neurological impairment; Children; Disrupting factors; Medicine & Public Health; Nuclear Medicine; Ultrasound; Oncology; Neuroradiology; Pediatrics; Imaging / Radiology
MRI is the most sensitive imaging modality in juvenile idiopathic arthritis (JIA), but has practical limitations. Optimizing the scanning protocol is, therefore, necessary to increase feasibility and patient comfort.
To determine the feasibility of bilateral non-contrast-enhanced open-bore MRI of knees and to assess the presence of literature-based MRI features in unsedated children with JIA.
Materials and methods
Children were classified into two clinical subgroups: active arthritis (group 1; n = 29) and inactive disease (group 2; n = 18). MRI features were evaluated using a literature-based score, comprising synovial hypertrophy, cartilage lesions, bone erosions, bone marrow changes, infrapatellar fat pad heterogeneity, effusion, tendinopathy and popliteal lymphadenopathy.
The MRI examination was successfully completed in all 47 children. No scan was excluded due to poor image quality. Synovial hypertrophy was more frequent in group 1 (36.2%), but was also seen in 19.4% of the knees in group 2. Infrapatellar fat pad heterogeneity was more prevalent in group 2 (86.1%; P = 0.008). Reproducibility of the score was good (Cohen kappa, 0.49–0.96).
Bilateral non-contrast-enhanced open-bore knee MRI is feasible in the assessment of disease activity in unsedated children with JIA. Signs differing among chidren with active and inactive disease include infrapatellar fat pad heterogeneity and synovial hypertrophy.
Magnetic resonance imaging; Juvenile idiopathic arthritis; Knee joint
Laterality defects are quite common in thoracoileopagus and parapagus dicephalus but rare in other types of conjoined twins.
To present the presumed laterality defects in cephalothoracoileopagus and prosopothoracoileopagus conjoined twins, based on the unilateral or bilateral absence or duplication of the spleen.
Materials and methods
Three human anatomical specimens of craniothoracoileopagus (CTIP) twins and one of prosopothoracoileopagus (PTIP) twins were investigated. The specimens were part of the Museum Vrolik collection of the Department of Anatomy and Embryology of the Academic Medical Centre, University of Amsterdam, The Netherlands. The specimens were taken out of their jars and scanned with multidetector CT and volumetric T2-weighted MRI at 1.5 T.
The internal anatomy of the specimens was largely in accordance with previous reports. However, there was no recognisable spleen in the right twin in one CTIP specimen, in the left twin in one other CTIP specimen, and in both twins in the third CTIP specimen and in the PTIP specimen.
Asplenia and polysplenia are considered reliable indicators of right and left isomerism, respectively. However, three of our four specimens had laterality patterns that did not correspond with those previously reported. Since no other parameters of laterality defects could be verified in these specimens, we concluded that asplenia was unlikely to be caused by laterality defects.
Conjoined twins; Laterality defects; Imaging; Historical specimen