Pediatric Radiology最新文献

Immunoglobulin G4-related (IgG4-R) inflammatory pseudotumor of the ureter is a rare benign lesion that can closely mimic malignancy on imaging. We report a case of a 5-year-8-month-old boy who presented with hematuria. Ultrasound (US) examination demonstrated pelvicalyceal and ureteral dilatation and a ureteral mass lesion measuring 39×18 mm. Unenhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) demonstrated an intraluminal ureteral mass causing unilateral urinary tract dilatation. This case is unique due to its pediatric ureteral location and misleading clinical presentation. Recognizing the characteristic US and MRI features of ureteral IgG4-R inflammatory pseudotumor, along with careful consideration of intraluminal ureteral lesions in the setting of unexplained urinary tract dilatation, may help avoid delayed diagnosis, chronic obstructive uropathy, and unnecessary radical surgery.

Congenital lung abnormalities are commonly encountered in the recent era of multi-modality fetal imaging. Congenital lung abnormalities encompass a diverse range of developmental disorders affecting the lung parenchyma, airways, and vascular structures. The anomalies, such as congenital pulmonary airway malformations (CPAM), bronchopulmonary sequestration, and congenital lobar overinflation (CLO), can present with varying degrees of severity, from asymptomatic cases to life-threatening respiratory distress. Ultrasound (US) plays a crucial role in the prenatal detection of these abnormalities, providing real-time imaging and facilitating early diagnosis and management planning. Magnetic resonance imaging (MRI), on the other hand, provides detailed morphological insights, particularly for complex cases. Its ability to visualize soft tissue structures and vascular anomalies without ionizing radiation makes it an indispensable tool in fetal and pediatric imaging. The combined use of US and MRI enhances diagnostic accuracy for fetuses with congenital lung abnormalities. These modalities continue to evolve, offering promising advancements in the understanding and management of these conditions. In this review article, we present a spectrum of common and uncommon congenital lung abnormalities, along with their typical imaging findings in US and MRI, and an approach to diagnosis.

Background: Preoperative identification of a ventrally positioned right hepatic artery (vRHA) is critical in congenital biliary dilatation (CBD), as unrecognized variants increase surgical risk. Detection on computed tomography (CT) is challenging in routine pediatric practice.

Objective: To develop and validate a You Only Look Once version 12 (YOLOv12)-based model for vRHA identification in contrast-enhanced CT using a targeted key-slice strategy.

Materials and methods: In this retrospective single-center study, 232 CBD patients (116 vRHA, 116 controls) were divided into training (n=186) and test (n=46) sets. Five YOLOv12 sub-models were trained as second-stage classifiers using 1,452 radiologist-selected key arterial-phase slices. Performance was assessed by precision, recall, F1-score, mean average precision (mAP), and area under the curve (AUC). Diagnostic performance was compared with two radiologists using DeLong's test.

Results: All sub-models showed perfect precision (1.000) with recall ranging from 0.684 to 0.895. YOLOv12n achieved the best performance (recall 0.842, F1-score 0.914, mAP50 0.989, AUC 0.977; 95% confidence interval, 0.913-1.000). It significantly outperformed the junior radiologist (AUC 0.737, P<0.001) and demonstrated comparable performance to the senior radiologist (AUC 0.947, P=0.515).

Conclusion: The YOLOv12n model achieved excellent diagnostic performance for vRHA identification on key CT slices and performed at a senior radiologist level, supporting its potential role in preoperative assessment.

Polysplenia syndrome is a rare congenital condition within the heterotaxy spectrum, characterized by multiple splenic nodules and abnormal visceral arrangement. Its presentation varies widely and may include cardiovascular, gastrointestinal, and vascular anomalies. We report an asymptomatic child incidentally diagnosed with polysplenia associated with a cleft palate and a retroaortic right renal vein, an unusual combination not commonly described. Imaging revealed multiple spleens, left-sided interrupted inferior vena cava with azygos continuation, and a retroaortic renal vein without hemodynamic compromise for the first time in literature to our knowledge. This case emphasizes the importance of thorough systemic evaluation in patients with craniofacial anomalies, as early recognition of associated malformations can guide appropriate management and optimize long-term outcomes for affected children worldwide and the importance of radiologic evaluation.

Background: The glymphatic system contributes to waste clearance in the brain and helps in maintaining neural health.

Objective: This study aimed to evaluate the age-related changes in magnetic resonance imaging (MRI) measurements of the index of diffusivity along the perivascular space (Along the Perivascular Space (ALPS) index) in infants and children less than 5 years of age.

Materials and methods: This IRB-approved, HIPAA-compliant study utilized diffusion-weighted MRI data from the Baby Connectome Project (BCP), which scanned developing subjects between birth and 5 years. We randomly selected subjects older than 2 months without significant imaging artifacts. The ALPS index was computed using diffusion tensor imaging (DTI)-derived diffusivity metrics along projection and association fibers. Multivariable linear regression and ANOVA were used to assess the impact of age, sex, and motion on ALPS index values across hemispheres and age groups.

Results: We analyzed 60 cases (58% female; mean age=25.4 months). ANOVA demonstrated higher right-hemisphere ALPS values in the 12-24-month, 37-48-month, and 49-65-month groups compared to the 2-12-month group (P<0.05), with no significant differences in the left hemisphere or average index, except in the 49-65-month group. Linear regression showed age as a positive predictor of ALPS values (P<0.001). Sex and head motion had no significant effects.

Conclusion: ALPS index values increase with age during the first 5 years of life, particularly in the right hemisphere, suggesting early developmental asymmetry in perivascular water diffusivity. These findings provide normative reference data and may inform future pediatric neuroimaging studies.

The elbow is a complex joint consisting of three separate articulations: ulnotrochlear, radiocapitellar, and proximal radioulnar. Collectively, these allow movements including flexion, extension, supination, and pronation. The developing pediatric elbow can be challenging to assess due to the predominance of cartilaginous epiphyseal and apophyseal structures, which are not evident on radiographs. Although MRI provides a comprehensive assessment of elbow anatomy, it can also be technically challenging. In a supine position with the arm to the side, the off-center position of the elbow can lead to decreased image quality due to magnetic field inhomogeneity with low signal-to-noise ratio (SNR) and poor fat suppression. Positions that attempt to bring the elbow to the MR iso-center can be uncomfortable in children suffering from elbow pain, leading to motion artifact. Furthermore, many of the soft tissue pathologies in the elbow are dynamic in nature and are best assessed using dynamic maneuvers. Ultrasound (US) is an ideal imaging modality for both static and dynamic assessment of the pediatric elbow joint and its soft tissue stabilizers. Additionally, comparison with the US of the contralateral elbow can serve as an internal control in the assessment of skeletally immature patients. In this narrative review, we describe the ultrasound technique for evaluating the pediatric elbow, the normal sonographic anatomy, and the common pathologies that may be encountered in practice.

Cardiovascular magnetic resonance cine imaging is limited in patients with an irregular cardiac rhythm as electrocardiographic gating requires a regular rhythm during image data acquisition. We describe a novel approach for imaging pediatric patients with ventricular bigeminy, using artificial triggering followed by metric optimized gating (MOG) reconstruction. This technique allows for the reconstruction of diagnostic quality images and permits quantitative flow and volumetric analyses. Unlike conventional methods of arrhythmia suppression or exclusion, this technique preserves the abnormal arrhythmic cycle, enabling a more comprehensive understanding of the patient's true hemodynamic physiology.

Background: The posterior fossa undergoes rapid development in utero, yet normative volumetric data are limited, especially during mid-gestation when most fetal MRIs are performed.

Objective: This study aimed to develop a segmentation method tailored to the fetal posterior fossa and establish normative growth trajectories for key infratentorial structures between 22 weeks and 32 weeks of gestation.

Materials and methods: Eighty-five pregnant women were prospectively recruited at a single institution. Inclusion criteria were normal singleton pregnancies between 19-40 weeks' gestation and maternal age 18-45 years. Exclusion criteria included fetal abnormalities, MRI contraindications, or significant maternal comorbidities. Eighteen fetuses were excluded, resulting in 67 normal fetuses (43 male, 24 female). Imaging was performed at 3 T using multiplanar T2-weighted sequences, reconstructed into isotropic volumes after motion correction and brain extraction. Segmentation labels were created using age-specific atlases from the Developing Human Connectome Project. Expert annotations defined the midbrain, pons, medulla, vermis, and cerebellar hemispheres. Images were registered to the atlases using the Symmetric Normalization (SyN) algorithm, with labels manually verified by a pediatric neuroradiologist. Volumes were normalized to total brain volume and analyzed using linear regression with gestational age and sex as predictors.

Results: Absolute volumes of all posterior fossa structures significantly increased with gestational age (P<0.001), showing strong linear associations (R²=0.80-0.87). The cerebellum exhibited the steepest growth (β=1,056.01, R²=0.87, P<0.001). Growth was symmetric with no significant left-right differences. Relative volumetric trends varied: the cerebellum increased proportionally (β=0.007, P<0.001), while the midbrain, pons, and medulla decreased relative to total brain volume. The vermis showed no significant association with gestational age but had sex-specific effects; males had smaller relative vermian volumes than females (β=-0.43, P=0.04), despite larger absolute posterior fossa volumes overall.

Conclusions: This study provides normative volumetric references for fetal posterior fossa structures between 22-32 weeks' gestation using a novel segmentation method. Absolute growth followed linear patterns, while relative measures revealed sex-specific variations in the vermis and cerebellum. These benchmarks may enhance diagnostic accuracy for detecting posterior fossa anomalies in clinical fetal MRI.

Musculoskeletal complaints are a frequent cause of emergency department visits in pediatric patients. While many of these visits are due to acute trauma, infection is also common and can cause substantial morbidity. This article provides a review of acute pediatric musculoskeletal infections with an additional emphasis on important differential diagnoses to consider. The scope includes cellulitis, abscess, necrotizing soft tissue infections, pyomyositis, infectious tenosynovitis, septic bursitis, septic arthritis, and osteomyelitis. Important differential considerations for these musculoskeletal infections will also be briefly reviewed.