Pediatric Radiology最新文献

Background: Cerebral magnetic resonance imaging (MRI) at term-equivalent age can provide prognostic information for extremely preterm infants; however, MRI-based reference values for ventricular size at term-equivalent age are sparse.

Objective: To present supratentorial ventricular size around term-equivalent age using MRI-based linear- and approximate volumetric measurements in extremely premature infants with and without germinal matrix-intraventricular haemorrhages, to assess whether ventricular size increases with haemorrhage presence and severity, and to determine which linear measurement best predicts volume of the lateral ventricles.

Materials and methods: In total, 119 infants born before 28 gestational weeks (mean chronological age at MRI 14.6 weeks) were prospectively included and categorised as having either no haemorrhage or germinal matrix-intraventricular haemorrhages based on cerebral ultrasound findings in the neonatal period. Brain MRI was performed around term-equivalent age. Linear measurements and approximate volumetric measurements of ventricular size were obtained.

Results: Infants with germinal matrix-intraventricular haemorrhages grade 4 had significantly larger supratentorial ventricular systems compared to those with no haemorrhage or grade 1, including both linear measurements and approximate volumetric measurements. No differences were observed between infants with no haemorrhage and grades 1 or 2. Bilateral haemorrhages resulted in larger ventricular sizes than unilateral haemorrhages. Frontal horn depth and thalamo-occipital distance demonstrated the strongest correlations with lateral ventricle volume.

Conclusion: Supratentorial ventricular size around term-equivalent age varies with severity and laterality of neonatal germinal matrix-intraventricular haemorrhages, with grade 4 associated with the largest ventricles. Frontal horn depth and thalamo-occipital distance were the best linear predictors of lateral ventricular volume.

MR angiography with ferumoxytol expands the toolset for imaging the pediatric abdominal vasculature. As an iron-based blood pool contrast agent, ferumoxytol allows for high-resolution imaging of the abdominal vessels that is not dependent on precise timing of contrast phases and can be used in patients with a contraindication to gadolinium-based contrast agents. At our institution, it has proven useful for abdominal indications including vascular mapping in the settings of portal hypertension, portosystemic shunts, and abdominal transplant evaluation, as well as for investigation of vascular malformations and vasculitis. Others have demonstrated its utility in tumor imaging, especially with hepatic tumors. In this review, we describe our protocol for ferumoxytol-enhanced MR angiography and discuss its various pediatric abdominal applications.

Background: The migration index (MI) is a quantitative measurement of femoral head extrusion used to help risk stratify neuromuscular hip dysplasia. However, MI relies upon the radiographically visible ossified capital femoral epiphysis which is only partially ossified in young children and therefore may potentially underestimate hip extrusion.

Objective: To compare proof-of-concept accuracy of using a metaphyseal and traditional MI to measure femoral head extrusion in children compared with an MRI-based anatomic reference standard.

Materials and methods: We reviewed 205 normal hips, each by MRI and x-ray, in patients aged 6 months - 6 years old. Three femoral head MI measurements were performed: (1) MRI-MI: percentage of the cartilaginous femoral head uncovered by the osseous acetabulum (anatomic reference standard); (2) traditional MI (TMI) x-ray: percentage of osseous capital femoral head uncovered by the osseous acetabulum; (3) metaphyseal MI x-ray (MeMI): percentage of the femoral head uncovered by the osseous acetabulum, using the metaphyseal vertex used as a surrogate for lateral margin of the cartilaginous femoral head. Statistical analysis of the three measurement techniques was performed using paired t-tests. Intraclass correlation coefficient was calculated.

Results: There was a statistically significant underestimation of femoral head extrusion using TMI and MeMI (P<0.05) when compared with MRI-MI, but MeMI more closely approximated the MRI-MI. Inter-reader reliability showed excellent agreement.

Conclusion: The MeMI better approximates the MRI anatomic landmarks for measuring the true degree of femoral head extrusion in children 6 months - 5 years of age. Its usage should be considered in lieu of the TMI in children under 5 years of age for radiographically determining MI.

Background: While single-energy hand computed tomography angiography (CTA) often yields suboptimal visualization of distal vessels, dual-energy computed tomography (CT) with low-keV virtual monoenergetic image (VMI) reconstruction enhances small-vessel conspicuity.

Objective: To evaluate the value of dual-energy CT VMIs in pediatric hand CTA.

Materials and methods: This retrospective study included 49 pediatric patients. Seven image series per patient were generated from dual-energy data: an M_0.5 image (50% 70 kVp+50% tin-filtered 150 kVp), a 70-kVp image, and five VMIs at 40-80 keV (10-keV increments). Objective metrics (attenuation, vessel noise, signal-to-noise ratio, contrast-to-noise ratio) and subjective scores were assessed for five vessels: the radial artery, the ulnar artery, the common palmar digital artery, and the proximal and distal parts of the proper palmar digital artery. Subjective image quality was independently evaluated by two radiologists using a 4-point Likert scale.

Results: The 40-keV VMIs provided the highest vascular attenuation across all vessels, albeit with the highest noise. Subjective scores for the radial, ulnar, and common palmar digital arteries showed no significant differences among the 40-keV, 50-keV, and 70-kVp series. However, for the small distal proper palmar digital arteries and total image quality, the 40-keV series was rated superior to the other series. No significant differences in image quality existed between the 70-kVp and 50-keV images.

Conclusion: For pediatric hand CTA, 40-keV VMIs provide optimal vascular conspicuity for small distal vessels, yielding the highest diagnostic confidence and total image quality score, and this benefit outweighs the associated increase in vessel noise.

Artificial intelligence (AI) holds immense promise in guiding clinical decision making in pediatric radiology, but its implementation in resource-constrained healthcare systems is limited by several significant challenges. The common AI methods, specifically deep learning models, used for image synthesis, reconstruction and segmentation require high-performance computers (HPC) and large memory capacities, which are often unavailable in low- and middle-income countries, especially in Sub-Saharan Africa. Long reconstruction times, inadequate hardware, and reliance on expensive commercial software further hinder adoption. These issues are compounded by the scarcity of annotated pediatric datasets, variability in imaging protocols, and limited data-sharing infrastructure, all of which widen the AI divide, particularly in pediatric imaging. Even when advanced AI models are developed, deploying them into clinical workflows remains difficult due to poor integration with existing picture archiving and communication systems (PACS) and the limited internet infrastructure for cloud-based solutions and data storage. Addressing these barriers will require intentional efforts to provide affordable high-performance computing resources, open-source pediatric datasets, federated learning approaches, and seamless workflow integration backed by robust region-specific AI regulations. This review sheds light on these barriers and highlights opportunities for AI-enabled solutions to become routine in pediatric radiology on the African continent.

Background: Radiation dose reduction is essential in paediatric lung computed tomography (CT). Advances in energy-integrating detector CT and deep-learning reconstruction may enable ultra-low-dose imaging comparable to photon-counting CT.

Objective: To evaluate the radiation dose and performance of an ultra-low-dose lung CT protocol using a wide-detector energy-integrating CT system in paediatric patients, focusing on effective radiation dose and diagnostic image quality.

Materials and methods: A total of 277 low-dose lung CT scans from 106 paediatric patients (age range, 113 days to 17.85 years) were retrospectively analysed. All scans were acquired in axial mode using a 256-slice-multidetector CT scanner with deep learning image reconstruction and attenuation-based Auto Prescription. Radiation dose parameters, including volume CT dose index, dose-length product, size-specific dose estimate, and effective dose, were calculated. Signal-to-noise ratio and contrast-to-noise ratio were assessed in standardised anatomical regions. Patients were stratified by age, and statistical analysis was conducted to evaluate dose trends and image quality metrics.

Results: There were significant differences between all age groups for all dose parameters (Kruskal-Wallis test, P<0.05). The median effective dose increased with age, ranging from 0.12 mSv (interquartile range (IQR) 0.09-0.14 mSv) in the 0-5-year group to 0.23 mSv (IQR 0.21-0.25 mSv) in adolescents aged 15 years to <18 years. Contrast-to-noise ratio and signal-to-noise ratio exhibited age-dependent variation with a small increase in older age groups. One-sided non-inferiority testing demonstrated that the signal-to-noise ratio and contrast-to-noise ratio in the youngest age group (0-5 years) were not significantly inferior to those in the ≥15-year group (P<0.05). All examinations were deemed diagnostically sufficient by board-certified paediatric radiologists. Non-disruptive artefacts such as cardiac motion and step artefacts occurred frequently but did not impair interpretation.

Conclusions: Ultra-low-dose lung CT using wide-detector energy-integrating CT with deep-learning image reconstruction allows for routine diagnostic imaging in children at radiation doses ranging from 0.12 mSv to 0.23 mSv, comparable to those reported for newer photon-counting CT systems. This approach provides a robust, clinically viable strategy for minimizing radiation exposure while maintaining diagnostic image quality.