Pediatric Radiology最新文献

This brief review focuses on the imaging of the craniocervical junction with particular attention to linear and angular craniometry. It attempts to answer the question of why there are so many measurements and how they are clinically useful. Congenital anomalies of the craniocervical junction will be discussed with an overview of craniocervical junction embryology and development. Entities affecting the craniocervical junction which will be discussed include platybasia, basilar invagination, atlanto-occipital assimilation, and assorted congenital anomalies.

Background: With the increasing use of magnetic resonance imaging (MRI) in children, radiologists frequently encounter incidental findings that may mimic pathology. One such underrecognized finding is T2-weighted hyperintensity in the superior extraconal orbital fat, which is occasionally mistaken for an infiltrative or neoplastic process.

Objective: Our objective was to characterize the imaging appearance, prevalence, and clinical associations of superior extraconal orbital fat T2 hyperintensity in pediatric MRI.

Materials and methods: We conducted a retrospective study of 143 pediatric patients (mean age 7.2±5.1 years) who underwent brain MRI with an orbit-specific protocol between 2015 and 2022. Patients were grouped based on the presence or absence of bilateral papilledema and whether imaging was performed under general anesthesia. Clinical data were extracted from the electronic medical records. Three neuroradiologists reviewed images for the presence of a hyperintense signal along the superior extraconal orbital fat. Interobserver agreement was calculated using Fleiss' kappa. Univariate and multivariable logistic regression analyses were performed to assess associations with age, anesthesia, gender, and magnet strength.

Results: Symmetric T2-hyperintense bands along the superior extraconal orbital fat were observed in 45.5% of patients. The finding was more common in younger children (4.4±3.9 years vs. 9.6±4.8 years; P<0.001). Multivariate analysis showed a significant negative correlation with age (P<0.001) and a positive correlation with papilledema (P=0.012), but no independent association with gender, anesthesia, or magnet strength. The hyperintensity was non-enhancing or only subtly enhancing. Clinical follow-up demonstrated no subsequent orbital or infiltrative pathology in the majority of patients, and most patients without documented follow-up underwent ambulatory MRI for evaluation of strabismus, which showed no evidence of infiltrative or other orbital disease.

Conclusion: Superior extraconal orbital fat T2 hyperintensity is a relatively common, likely non-pathologic MRI finding in pediatric patients, particularly in younger children, and the apparent association with anesthesia likely reflects age-related confounding. Awareness of this benign appearance may help avoid diagnostic confusion and prevent unnecessary workup or intervention.

Background: It is important to obtain an accurate volumetric characterization of fetal posterior fossa growth on magnetic resonance imaging (MRI).

Objective: This study analyzes the normal growth, sexual dimorphism, and lateral asymmetry of the fetal posterior fossa during the late second and third trimesters.

Materials and methods: A total of 100 fetuses (23-40 weeks gestational age (GA)) with normal brain development were retrospectively included in this study. The bilateral posterior fossa, cerebellar hemisphere, and brainstem (including the midbrain, pons, and medulla oblongata) were manually segmented on in vivo fetal MRIs. Normal growth, sexual dimorphism, and lateral asymmetry were analyzed after the fossa volumes were obtained.

Results: The total, left, and right posterior fossa volumes all linearly increased with GA. The volume of the right posterior fossa was significantly greater than that of the left and increased slightly faster. The cerebellar volume exponentially increased with increasing GA. The right cerebellar volume was significantly greater than the left cerebellar volume. The bilateral cerebellar volume had a similar growth rate, which accelerated and increased more quickly than did that of the posterior fossa volume after 35 weeks GA. The brainstem volume linearly increased with GA. The pontine volume increased the fastest, followed by the midbrain volume, and the medullary volume increased the slowest. The relationship between the volume of the cerebrospinal fluid in the posterior fossa and GA was described adequately by a second-order polynomial curve, which increased before 30 weeks GA but gradually decreased after 35 weeks GA. No sexual dimorphism was detected in any of the measurements.

Conclusions: The development of the fetal posterior fossa follows a specific spatiotemporal course, and volumetric measurements reveal structure-specific and GA-related changes with different rates and lateral asymmetries. These results are valuable for assessing normal fetal posterior fossa development in utero.

Identifying the artery of Adamkiewicz (AoA) is essential for minimizing the risk of spinal cord ischemia that can result from injury or displacement during aortopexy. A pre-operative CT angiogram (CTA) is commonly requested; however, locating the artery can be challenging due to its small size and variable course. To enhance the visualization of the artery of Adamkiewicz, it is effective to increase the tube current while maintaining a low kV of 70 and raising the Hounsfield unit (HU) trigger threshold. This method adheres to the As Low As Reasonably Achievable (ALARA) principle, ensuring a reliably diagnostic study.

Palpable soft-tissue masses in the pediatric head and neck are common and encompass a broad differential that includes congenital, infectious, inflammatory, and neoplastic processes. Owing to its ability to characterize lesion morphology, vascularity, and internal architecture without ionizing radiation, ultrasonography (US) remains the primary imaging modality for initial evaluation. This review focuses on pediatric head and neck masses, emphasizing practical US-based assessment and differential diagnosis. Entities discussed include common congenital lesions such as dermoid cysts, thyroglossal duct cysts, and branchial cleft anomalies, salivary gland abnormalities (including sialadenitis, sialolithiasis, ranulas, and salivary tumors), thymic lesions (such as ectopic thymus and thymic cysts), and thyroid abnormalities (including ectopic thyroid tissue, thyroid nodules, and thyroid malignancy).

Background: Fontan-associated liver disease (FALD) is associated with morbidity and mortality in patients with palliated single ventricle congenital heart disease.

Objective: To develop machine learning models using radiomic features from T1-weighted, T2-weighted, and diffusion-weighted MRI with pertinent clinical variables to predict Fontan failure and correlates of FALD severity in patients who underwent the Fontan operation.

Materials and methods: In this retrospective study of abdominal MRI examinations and clinical record data from 131 Fontan palliation patients (age range 9.1 - 53.3 years old), radiomic features from the liver and spleen were extracted using axial T1-weighted, T2-weighted fat-suppressed, and diffusion-weighted sequences. Patients were categorized by a composite clinical outcome (i.e., Fontan failure) and by correlates of FALD severity, including liver shear stiffness and portal hypertension. Support vector machine (SVM) and multivariable logistic regression models were used to perform two-class classification using radiomic features and/or clinical data. All models were trained and evaluated using five-fold cross-validation (CV).

Results: The best radiomic-only model utilized T2-weighted imaging of both organs with logistic regression to predict the presence of portal hypertension, achieving an AUROC of 0.85±0.01. Clinical-only models showed inferior diagnostic accuracy with the highest AUROC of 0.70±0.08. Combining radiomic and clinical features also did not enhance performance compared to radiomic-only models, with the highest AUROC of 0.77±0.05. Ensemble modeling, which incorporated radiomics from all three MRI sequences, yielded AUROCs ranging from 0.33 to 0.72.

Conclusion: Models incorporating radiomic features from abdominal MRI in Fontan circulation patients demonstrate moderate diagnostic performance for predicting Fontan failure as well as correlates of FALD severity. These models outperformed models containing only clinical electronic health record data and did not improve with ensembled radiomic and clinical data.

Background: Magnetic resonance imaging (MRI) in children requires multiple sequences, leading to lengthy exams and motion-related challenges. Synthetic MRI generates multiple contrasts from a single acquisition, and integration of 3D-quantification using an interleaved Look-Locker acquisition sequence with a T2 preparation pulse (3D-QALAS) sequence with scan-specific deep-learning-based subspace reconstruction (Zero-DeepSub) enables high-resolution isotropic imaging with potential clinical utility.

Objective: To evaluate synthetic images generated from a 3D-QALAS sequence with Zero-DeepSub relative to conventional MRI sequences in pediatric brain MRI.

Materials and methods: This prospective initial experience included 26 pediatric patients (mean age 8.4 years) who underwent clinically indicated brain MRI between November 2023 and January 2024. Synthetic T1-weighted, T2-weighted, and fluid-attenuated inversion recovery (FLAIR) images were generated from quantitative maps using 3D-QALAS with Zero-DeepSub reconstruction. Two neuroradiologists independently assessed seven predefined imaging findings on synthetic and conventional images, with discrepancies adjudicated by a third reader. This reader also performed a semiquantitative evaluation of image quality using a 5-point Likert scale. Statistical analysis included descriptive statistics, interobserver agreement (Cohen's kappa), and Wilcoxon signed-rank tests; positive predictive value (PPV) and negative predictive value (NPV) were also calculated.

Results: Synthetic images showed high sensitivity and specificity for mass/lesion, encephalomalacia, and collections, with perfect reader agreement. Gliosis demonstrated high sensitivity but moderate specificity for one reader. Abnormal enhancement had the lowest sensitivity (0.40). Interobserver agreement was moderate for gliosis (κ=0.55) and almost perfect (κ=0.83-1.00) for other findings. Semiquantitative evaluation revealed no significant difference between synthetic and conventional FLAIR, T1-weighted imaging, or post-contrast sequences (P>0.1), while conventional T2-weighted imaging was significantly superior (P<0.001).

Conclusion: 3D-QALAS with Zero-DeepSub reconstruction enables the synthesis of high-resolution, clinically interpretable brain images in pediatric patients, including post-contrast sequences. While conventional T2-weighted imaging remained superior, other synthetic contrasts were rated comparable to conventional images. This promising technique holds potential to reduce scan times in pediatric neuroimaging protocols, but further optimization and validation are required before clinical implementation.