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Purpose: This study aimed to evaluate the usefulness of two-dimensional shear wave elastography (2D-SWE) in diagnosing hepatic veno-occlusive disease (VOD) in pediatric patients.Methods: This study retrospectively included pediatric patients who underwent hematopoietic stem cell transplantation (HSCT) between November 2019 and January 2021. All 34 patients (8.7±5.0 years) were examined using 2D-SWE for an initial diagnosis. A subgroup analysis was performed using the data from follow-up examinations of patients diagnosed with VOD. The characteristics of the initial VOD diagnosis were compared with the longitudinal changes observed in VOD patients who underwent multiple ultrasound examinations.Results: In total, 19 patients were diagnosed with VOD at 17.6±9.4 days after HSCT. All VOD patients showed hepatomegaly, ascites, and gallbladder wall thickening. Liver stiffness was higher in VOD patients than in non-VOD patients (12.4±1.1 vs. 6.3±0.8 kPa, P

Leg length discrepancy (LLD) is a common problem that can cause long-term musculoskeletal problems. However, measuring LLD on radiography is time-consuming and labor intensive, despite being a simple task.To develop and evaluate a deep-learning algorithm for measurement of LLD on radiographs.In this Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study, radiographs were obtained to develop a deep-learning algorithm. The algorithm developed with two U-Net models measures LLD using the difference between the bilateral iliac crest heights. For performance evaluation of the algorithm, 300 different radiographs were collected and LLD was measured by two radiologists, the algorithm alone and the model-assisting method. Statistical analysis was performed to compare the measurement differences with the measurement results of an experienced radiologist considered as the ground truth. The time spent on each measurement was then compared.Of the 300 cases, the deep-learning model successfully delineated both iliac crests in 284. All human measurements, the deep-learning model and the model-assisting method, showed a significant correlation with ground truth measurements, while Pearson correlation coefficients and interclass correlations (ICCs) decreased in the order listed. (Pearson correlation coefficients ranged from 0.880 to 0.996 and ICCs ranged from 0.914 to 0.997.) The mean absolute errors of the human measurement, deep-learning-assisting model and deep-learning-alone model were 0.7 ± 0.6 mm, 1.1 ± 1.1 mm and 2.3 ± 5.2 mm, respectively. The reading time was 7 h and 12 min on average for human reading, while the deep-learning measurement took 7 min and 26 s. The radiologist took 74 min to complete measurements in the deep-learning mode.A deep-learning U-Net model measuring the iliac crest height difference was possible on teleroentgenograms in children. LLD measurements assisted by the deep-learning algorithm saved time and labor while producing comparable results with human measurements.

We aimed to analyze brain imaging findings and neurodevelopmental outcomes of preterm infants diagnosed with cerebral palsy (CP).Brain magnetic resonance imaging (MRI) of preterm infants born between 23 and 32 weeks' gestation and diagnosed with CP at two years corrected age (CA) were evaluated. Brain lesions were categorized as periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), and cerebellar hemorrhage (CBH) and graded by the severity. Neurodevelopmental outcomes were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) at 18-24 months CA, and the Korean Ages and Stages Questionnaire (K-ASQ) at 18 and 24 months CA.CP was found in 38 (6.1%) children among 618 survivors. Cerebellar injury (CI) of high-grade CBH and/or atrophy accounted for 25%. Among patients with supratentorial lesions, those having CI showed significantly lower scores on each K-ASQ domain except gross motor than patients without CI. They also revealed a high proportion of patients below the cut-off value of K-ASQ in language, fine motor, and problem-solving domains (P0.05), and lower Bayley-III language composite scores (P = 0.038).Poor neurodevelopmental outcomes other than motor function were associated with CI. Evaluation of the cerebellum may help predict functional outcomes of patients with CP.

Background To describe the radiological features of Gorham–Stout disease (GSD) as evaluated using plain radiography and dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) imaging techniques. Methods Clinical and conventional imaging data were retrospectively reviewed for 15 patients with GSD between January 2001 and December 2020. After December 2018, DCMRL examinations were performed for lymphatic vessel evaluation in patients with GSD and reviewed in four patients. Results The median age at diagnosis was 9 years (range: 2 months–53 years). The clinical manifestations were dyspnea in seven patients (46.7%), sepsis in 12 (80.0%), orthopedic problems in seven (46.7%), and bloody chylothorax in seven (46.7%). The common sites of osseous involvement were the spine (73.3%) and pelvic bone (60.0%). Among the non-osseous involvements, peri-osseous infiltrative soft-tissue abnormalities adjacent to the area of bone involvement were the most common (86.7%), followed by splenic cysts (26.7%) and interstitial thickening (26.7%). DCMRL demonstrated weak central conducting lymphatic flow in two patients with abnormal giant tortuous thoracic ducts and no flow in one patient. All patients who underwent DCMRL in this study presented with altered anatomical lymphatics and functional flow with collateralization. Conclusion DCMRL imaging and plain radiography are very useful for determining the extent of GSD. DCMRL is a novel imaging tool for the visualization of abnormal lymphatics in patients with GSD, which helps in further treatment. Therefore, in patients with GSD, it might be necessary to obtain not only plain radiographs but also MR and DCMRL images.

To develop an automatic segmentation algorithm using a deep neural network with transfer learning applicable to whole-body PET-CT images in children.For model development, we utilized transfer learning with a pre-trained model based on adult patients. We used CT images of 31 pediatric patients under 19 years of age (mean age, 9.6 years) who underwent PET-CT from institution #1 for transfer learning. Two radiologists manually labeled the skin, bone, muscle, abdominal visceral fat, subcutaneous fat, internal organs, and central nervous system in each CT slice and used these as references. For external validation, we collected 14 pediatric PET/CT scans from institution #2 (mean age, 9.1 years). The Dice similarity coefficients (DSCs), sensitivities, and precision were compared between the algorithms before and after transfer learning. In addition, we evaluated segmentation performance according to sex, age (≤ 8 vs.8 years), and body mass index (BMI, ≤ 20 vs.20 kg/mThe algorithm after transfer learning showed better performance than the algorithm before transfer learning for all body compositions (p0.001). The average DSC, sensitivity, and precision of each algorithm before and after transfer learning were 98.23% and 99.28%, 98.16% and 99.28%, and 98.29% and 99.28%, respectively. The segmentation performance of the algorithm was generally not affected by age, sex, or BMI, except for precision in the body muscle compartment.The developed model with transfer learning enabled accurate and fully automated segmentation of multiple tissues on whole-body CT scans in children.• We utilized transfer learning with a pre-trained segmentation algorithm for adult to develop an algorithm for automated segmentation of pediatric whole-body CT. • This algorithm showed excellent performance and was not affected by sex, age, or body mass index, except for precision in body muscle.

Abusive head trauma (AHT) is the most common and serious form of child abuse and a leading cause of traumatic death in infants and young children. The biomechanics of head injuries include violent shaking, blunt impact, or a combination of both. Neuroimaging plays an important role in recognizing and distinguishing abusive injuries from lesions from accidental trauma or other causes, because clinical presentation and medical history are often nonspecific and ambiguous in this age group. Understanding common imaging features of AHT can increase recognition with high specificity for AHT. In this review, we discuss the biomechanics of AHT, imaging features of AHT, and other conditions that mimic AHT.

To investigate the clinical characteristics and prevalence of paediatric anti-myelin oligodendrocyte glycoprotein (MOG) antibody-associated autoimmune encephalitis.A total of 94 paediatric patients (46 males, 48 females, median age 9 years 5 months, range: 8 months-17 years 8 months) with autoimmune encephalitis were recruited at Seoul National University Children's Hospital. We evaluated autoantibody status and identified patients with anti-MOG antibody-associated autoimmune encephalitis. Retrospective reviews of medical records were performed to describe clinical presentations, laboratory findings, treatments, and outcomes.Eight patients (five males, three females, median age 11 years 9 months) with anti-MOG antibody-associated encephalitis were identified (8.5% of those with autoimmune encephalitis), one of whom was copositive for anti-N-methyl-d-aspartate receptor (NMDAR) antibodies. Anti-NMDAR antibodies were identified in 23 patients (23 out of 94, 24.5%). Unilateral or bilateral cortical involvement was identified in five patients. Focal contrast enhancement was also identified in three of the five patients with cortical lesions. All patients showed favourable response to immunotherapy with a Modified Rankin Scale ≤2 at the last follow-up. Relapse was found in one patient and clinico-radiological remission was achieved with cyclic intravenous immunoglobulin therapy.Anti-MOG antibody-associated encephalitis accounts for a significant proportion of clinically defined paediatric patients with autoimmune encephalitis. Anti-MOG antibody-associated encephalitis should be included in the clinical spectrum of anti-MOG-associated diseases.

Purpose: The purpose of this study was to use shear-wave elastography (SWE) to assess testicular stiffness changes during the Valsalva maneuver in adolescents and young adults with varicocele, to compare these changes according to clinical severity, and to evaluate the role of SWE in the diagnosis of varicocele.Methods: This study included patients undergoing testicular ultrasonography for the diagnosis of varicocele or for post-varicocelectomy follow-up between June 2016 and February 2017. Fifty-four testicles of 27 consecutive patients (mean age, 15.9 years) were classified by clinical grade (grade 0-3). Using SWE, mean testicular stiffness (Emean) was measured at rest and during the Valsalva maneuver. The correlations between multiple ultrasonographic parameters (volume asymmetry, Emean at rest, and absolute and percentage changes in Emean during the Valsalva maneuver) and clinical grade were assessed using the Spearman correlation test.Results: The Emean at rest was similar across clinical grades. During the Valsalva maneuver, increased testicular stiffness was frequently observed in patients with grade 2 or 3 varicocele but rarely observed in those with grade 0 or 1 varicocele. The changes in Emean were positively correlated with the clinical grade (all P0.05).Conclusion: A transient, reversible increase in testicular stiffness during the Valsalva maneuver was observed in adolescents with high-grade varicocele, and the degree of stiffness change was correlated with the clinical grade. Stiffness change identified using SWE during the Valsalva maneuver is a potential surrogate indicator of venous congestion.

Purpose: This study evaluated the diagnostic performance of contrast-enhanced voiding urosonography (ce-VUS) using a second-generation ultrasound contrast agent for the diagnosis of vesicoureteral reflux (VUR) and intrarenal reflux (IRR), and compared it with that of standard fluoroscopic voiding cystourethrography (VCUG).Methods: Thirty-two consecutive children from April to October 2019 were included in this study. ce-VUS and VCUG were performed simultaneously by two operators with intravesical infusion of a mixture of ultrasound contrast medium, iodinated contrast medium and water. Two pediatric radiologists independently reviewed the ce-VUS and VCUG images and reported the presence and degree of VUR (grades I-V), and the presence and type of IRR.Results: Twenty-seven of 63 urinary systems showed VUR. Interobserver agreement for VUR grading was very good for both examinations (κ=0.87; 95% confidence interval [CI], 0.82 to 0.92 for ce-VUS and κ=0.92; 95% CI, 0.87 to 0.96 for VCUG). The detection rate of VUR showed no significant difference between the two examinations (P=0.370). Four cases of VUR were missed on ce-VUS, while one case of VUR was missed on VCUG. All four false-negative cases on ce-VUS were grade 1 VUR. The two examinations showed very good agreement regarding VUR grading (κ =0.89; 95% CI, 0.81 to 0.96). IRR was more frequently detected with ce-VUS than with VCUG (10 cases with ce-VUS vs. 3 cases with VCUG, P=0.016).Conclusion: ce-VUS showed very good agreement with VCUG for detecting grade 2 VUR and above, while grade 1 VUR was sometimes missed with ce-VUS. IRR was more frequently detected with ce-VUS than with VCUG.

Background Cerebral arteriovenous malformation (AVM) can rarely occur in conjunction with moyamoya disease (MMD). There is still no consensus on how to treat AVM when accompanied by MMD. In this study, we assessed the clinical features and suggested appropriate management when AVM was combined with MMD. Methods From August 1994 to December 2020, 7 out of 4004 patients with MMD were found to have AVM. The Karnofsky Performance Scale (KPS) was used to evaluate the clinical outcomes of AVM and MMD. KPS greater than 80 was classified as a good outcome. In addition, the radiologic outcomes of the patients were evaluated. Results The incidence of AVM with MMD was 1.7 per 1000 persons. Five patients underwent bypass surgery for MMD, and 5 patients underwent Gamma Knife surgery (GKS) for concurrent AVM. Postoperative perfusion magnetic resonance imaging and brain single photon emission computerized tomography showed improved cerebral hemodynamics in 4 out of 7 territories. Postoperative cerebral angiography showed good revascularization in 4 out of 8 territories. After GKS, 4 patients showed complete obliteration, and 1 patient showed a significantly decreased AVM size. Six patients showed favorable clinical outcomes (KPS 80–100), and 1 patient with delayed GKS for AVM had a poor outcome (KPS 20) due to AVM rupture. Conclusions In this study, AVM tended to occur where the angiographic stage of MMD was higher. When AVM is combined with MMD, MMD bypass surgery is recommended based on symptoms and cerebral perfusion status. For AVM, less invasive but effective treatments, such as GKS, should be implemented as soon as possible.

Background To describe the radiological features of Gorham–Stout disease (GSD) as evaluated using plain radiography and dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) imaging techniques. Methods Clinical and conventional imaging data were retrospectively reviewed for 15 patients with GSD between January 2001 and December 2020. After December 2018, DCMRL examinations were performed for lymphatic vessel evaluation in patients with GSD and reviewed in four patients. Results The median age at diagnosis was 9 years (range: 2 months–53 years). The clinical manifestations were dyspnea in seven patients (46.7%), sepsis in 12 (80.0%), orthopedic problems in seven (46.7%), and bloody chylothorax in seven (46.7%). The common sites of osseous involvement were the spine (73.3%) and pelvic bone (60.0%). Among the non-osseous involvements, peri-osseous infiltrative soft-tissue abnormalities adjacent to the area of bone involvement were the most common (86.7%), followed by splenic cysts (26.7%) and interstitial thickening (26.7%). DCMRL demonstrated weak central conducting lymphatic flow in two patients with abnormal giant tortuous thoracic ducts and no flow in one patient. All patients who underwent DCMRL in this study presented with altered anatomical lymphatics and functional flow with collateralization. Conclusion DCMRL imaging and plain radiography are very useful for determining the extent of GSD and are essential for diagnosis. DCMRL is an essential imaging tool for the visualization of abnormal lymphatics in patients with GSD, which helps in further treatment. Therefore, in patients with GSD, it is necessary to obtain not only plain radiographs but also MR and DCMRL images.

Background Pediatric patients with liver disease require noninvasive monitoring to evaluate the risk of fibrosis progression. This study aimed to identify the significant factors affecting liver stiffness values using two-dimensional shear-wave elastography (2D-SWE), and determine whether liver stiffness can predict the fibrosis stage of various childhood liver diseases. Methods This study included 30 children (22 boys and 8 girls; mean age, 5.1 ± 6.1 years; range, 7 days–17.9 years) who had undergone biochemical evaluation, 2D-SWE examination, histopathologic analysis of fibrosis grade (F0 to F3), assessment of necroinflammatory activity, and steatosis grading between August 2016 and March 2020. The liver stiffness from 2D-SWE was compared between fibrosis stages using Kruskal–Wallis analysis. Factors that significantly affected liver stiffness were evaluated using univariate and multivariate linear regression analyses. The diagnostic performance was determined from the area under the receiver operating curve (AUC) values of 2D-SWE liver stiffness. Results Liver stiffness at the F0-1, F2, and F3 stages were 7.9, 13.2, and 21.7 kPa, respectively (P P P = 0.021, respectively). However, in patients with alanine aminotransferase (ALT) levels below 200 IU/L, the only factor affecting liver stiffness was fibrosis stage (P = 0.030). The liver stiffness value could distinguish significant fibrosis (≥ F2) with an AUC of 0.950 (cutoff value, 11.3 kPa) and severe fibrosis (F3 stage) with an AUC of 0.924 (cutoff value, 18.1 kPa). The 2D-SWE values for differentiating significant fibrosis were 10.5 kPa (≥ F2) and 18.1 kPa (F3) in patients with ALT levels below 200 IU/L. Conclusion The liver stiffness values on 2D-SWE can be affected by both fibrosis and necroinflammatory grade and can provide excellent diagnostic performance in evaluating the fibrosis stage in various pediatric liver diseases. However, clinicians should be mindful of potential confounders, such as necroinflammatory activity or transaminase level, when performing 2D-SWE measurements for liver fibrosis staging.

Purpose This study aimed to assess the feasibility of contrast-enhanced ultrasound (CEUS) for the diagnosis of acute pyelonephritis (APN) in pediatric patients with febrile urinary tract infection (UTI). Materials and methods Between March 2019 and January 2021, study participants with suspected UTI were assessed for APN using ultrasound. Parenchymal echogenicity changes, renal pelvis dilatation, and the presence of a focal suspected lesion were assessed using conventional grayscale ultrasound. The presence and location of a decreased perfusion area were evaluated using color Doppler ultrasound (CDUS) and CEUS. Agreement between each ultrasound examination and a 99mTc‒dimercaptosuccinic acid (DMSA) scan was assessed using the κ value, and the most visible period of the lesion was evaluated using CEUS. Results This study enrolled 21 participants (median age, 8.0 months; range, 2.0–61.0 months) with isolated urinary tract pathogens. Five increased parenchymal echotextures (11.9%) and 14 renal pelvic dilatations (33.3%) were confirmed, but no focal lesions were detected on the grayscale images. CDUS and CEUS showed decreased local perfusion suggestive of APN in two and five kidneys, respectively. DMSA scan showed substantial agreement with CEUS findings (κ = 0.80, P = 0.010), but other grayscale and CDUS findings did not agree with DMSA scan results (P > 0.05). All lesions were best observed in the late parenchymal phase on CEUS. Conclusion CEUS can reveal renal perfusion defects in pediatric patients with suspected APN without radiation exposure or sedation; therefore, CEUS may be a feasible and valuable diagnostic technique.

Juvenile xanthogranuloma (JXG) is a type of non-Langerhans cell histiocytosis that most commonly manifests as a solitary cutaneous lesion of the head and neck in children. Intracranial JXG is extremely rare. Although it is widely known that JXG skin lesions gradually disappear over time without treatment, treatment guidelines for intracranial JXG have not been established. It is very difficult to predict whether an intracranial lesion is JXG with only a pre-operative imaging work-up without pathologic confirmation. We report a case of the youngest, a 3-month-old male infant with an intracranial extra-axial mass with rapid growth for 2 months. Additionally, we suggest characteristic MRI findings for intracranial extra-axial JXG of a low T2 signal and a kidney bean shape.

Imatinib is a BCR-ABL tyrosine kinase inhibitor used for the treatment of a variety of diseases including Philadelphia chromosome positive (Ph+) leukemia. We report a 15 year old male patient presenting with symptomatic acute intracerebral hemorrhage (ICH) in midbrain while on imatinib more than three years after completion of therapy for Ph + B-ALL. The patient denied recent trauma history and consumption of other medication. Laboratory findings did not show any signs of relapse, coagulopathy nor thrombocytopenia. Under the impression of imatinib related ICH, imatinib was discontinued and with conservative management the patient recovered without neurologic sequalae. This case demonstrates the first pediatric case of spontaneous ICH as a rare complication of imatinib.

Background Several studies have suggested that adverse neurodevelopment could be induced by systemic inflammation in preterm infants. We aimed to investigate whether preterm infants with systemic inflammation would have impaired neurodevelopment and which biomarkers and neurophysiologic studies during inflammation are associated with poor neurodevelopment. Methods This prospective cohort study enrolled infants born before 30 weeks of gestation or with birth weight n = 49), I (systemic inflammation, n = 45). Blood and cerebrospinal fluid samples for markers of brain injury and inflammation were collected and amplitude-integrated electroencephalography (aEEG) was performed within 4 h of septic workup. We evaluated aEEG at 35 weeks postmenstrual age (PMA), head circumference at 36 weeks PMA, and brain MRI at discharge. The Bayley Scales of Infant and Toddler Development III (Bayley-III) was performed at a corrected age (CA) of 18 months. Results The I group had more white matter injuries (2 vs. 26.7%, Control vs. I, respectively) at the time of discharge, lower brain functional maturation (9.5 vs. 8), and smaller head size (z-score − 1.45 vs. -2.12) at near-term age and poorer neurodevelopment at a CA of 18 months than the control (p p Conclusions Systemic inflammation induced by clinical infection and NEC are associated with neurodevelopmental impairment in preterm infants. The seizure spike on aEEG, elevated I/T ratio, CRP, and plasma TNF-alpha during inflammatory episodes are associated with poor neurodevelopment.

A cerebral arteriovenous malformation (AVM) is a congenital and static disease. However, there are increasing reports of acquired AVMs. The pathophysiology of an acquired AVM has not been fully elucidated but the suggested pathophysiology is a combination of genetic abnormalities and inflammatory cytokines caused by previous brain insults. We report a patient who developed an acquired AVM after the treatment for a brain abscess. She underwent Gamma Knife surgery to treat the acquired AVM. It is necessary to understand the characteristics of acquired AVMs and to further research acquired AVMs.

Preoperative estimation of the insertion depth angle of cochlear implant (CI) electrodes is essential for surgical planning. The purpose of this study was to determine the cochlear size using preoperative CT and to investigate the correlation between cochlear size and insertion depth angle in morphologically normal cochlea. Thirty-five children who underwent CI were included in this study. Cochlear duct length (CDL) and the diameter of the cochlear basal turn (distance A/B) on preoperative CT and the insertion depth angle of the CI electrode on postoperative radiographs were independently measured by two readers. Correlation between cochlear size and insertion depth angle was evaluated. Interobserver agreement was calculated using the intraclass correlation coefficient (ICC). The mean CDL, distance A, and distance B of 70 ears were 36.20 ± 1.57 mm, 8.67 ± 0.42 mm, and 5.73 ± 0.32 mm, respectively. The mean insertion depth angle was 431.45 ± 38.42°. Interobserver agreements of CDL, distance A/B, and insertion depth angle were fair to excellent (ICC 0.864, 0.862, 0.529, and 0.958, respectively). Distance A (r = − 0.7643) and distance B (r = − 0.7118) showed a negative correlation with insertion depth angle, respectively (p 0.05). The CDL and cochlear distance can be reliably obtained from preoperative CT. Distance A can be used as a predictive marker for estimating insertion depth angle during CI surgery.

BackgroundA low-degree tumor necrosis after neoadjuvant chemotherapy is a poor prognostic factor for osteosarcoma (OSA). However, the role of high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation in OSA remains controversial. We analyzed the treatment outcomes and prognostic factors of nonmetastatic OSA and compared the HDC and conventional chemotherapy (CC) outcomes of patients with MethodsWe retrospectively evaluated patients with OSA treated at the Seoul National University Children’s Hospital from 2000 to 2020. Totally, 113 patients with non-metastatic OSA at diagnosis were included. The majority were treated with cisplatin, doxorubicin, and methotrexate as neoadjuvant chemotherapy. This was continued when the postoperative necrosis rate was >90% (good response [GR]), whereas most cases with ResultsThe median age at diagnosis was 12.6 years (range, 5.0–20.3), and 61.9% of patients were men. The 5-year event-free survival (EFS) and overall survival (OS) rates were 75.8% and 91.5%, respectively. Among these, 59 and 44 patients were included in the GR and PR groups, respectively. The GR group had a better 5-year EFS rate than the PR group (82.4% vs. 67.3%, p=0.071). Age at diagnosis, sex, tumor site, type of neoadjuvant chemotherapy, and degree of tumor necrosis were not different between the PR-HDC (n=24) and PR-CC (n=20) groups. The 5-year EFS and OS rates in the PR-HDC (n=24) and PR-CC (n=20) groups were 78.6% and 53.6% (p=0.065) and 100% and 76.9% (p=0.024), respectively. In the Cox regression analysis, the PR-CC group (hazard ratio, 4.95; p=0.004) and age ≥12 years (hazard ratio, 2.68; p=0.024) were significant risk factors for 5-year EFS.ConclusionsHDC showed favorable outcomes in patients with non-metastatic OSA and

Deep learning-based MRI reconstruction has recently been introduced to improve image quality. This study aimed to evaluate the performance of deep learning reconstruction in pediatric brain MRI.A total of 107 consecutive children who underwent 3.0 T brain MRI were included in this study. T2-weighted brain MRI was reconstructed using the three different reconstruction modes: deep learning reconstruction, conventional reconstruction with an intensity filter, and original T2 image without a filter. Two pediatric radiologists independently evaluated the following image quality parameters of three reconstructed images on a 5-point scale: overall image quality, image noisiness, sharpness of gray-white matter differentiation, truncation artifact, motion artifact, cerebrospinal fluid and vascular pulsation artifacts, and lesion conspicuity. The subjective image quality parameters were compared among the three reconstruction modes. Quantitative analysis of the signal uniformity using the coefficient of variation was performed for each reconstruction.The overall image quality, noisiness, and gray-white matter sharpness were significantly better with deep learning reconstruction than with conventional or original reconstruction (all P 0.001). Deep learning reconstruction had significantly fewer truncation artifacts than the other two reconstructions (all P 0.001). Motion and pulsation artifacts showed no significant differences among the three reconstruction modes. For 36 lesions in 107 patients, lesion conspicuity was better with deep learning reconstruction than original reconstruction. Deep learning reconstruction showed lower signal variation compared to conventional and original reconstructions.Deep learning reconstruction can reduce noise and truncation artifacts and improve lesion conspicuity and overall image quality in pediatric T2-weighted brain MRI.

Esophageal balloon dilatation is an effective treatment for anastomotic strictures, but the factors affecting the outcome of dilatation remain unclear.To investigate the predictive factors of esophageal balloon dilatation outcome in children with anastomotic stricture after esophageal atresia repair.We retrospectively reviewed children with esophageal atresia who underwent esophageal balloon dilatation for postoperative strictures between August 2007 and February 2021. We investigated each child's age, weight and height; type of esophageal atresia surgery; shape, length and level of stricture; esophageal balloon dilatation balloon size; application of mitomycin; number of inflation sessions; and number of esophageal balloon dilatation sessions. The outcome of each esophageal balloon dilatation session was determined as improvement in stricture diameter between pre- and post-esophageal balloon dilatation esophagography. We used uni- and multivariate analyses with generalized estimating equations to evaluate outcome predictors.Overall, 69 children (mean age, 2.3 years; 45 boys) underwent 227 esophageal balloon dilatations. In the univariate analysis, the positive effect of esophageal balloon dilatation decreased with increased age, weight, height, balloon size and number of esophageal balloon dilatation sessions. Additionally, the positive effect was decreased in cervical-level strictures and with the application of mitomycin during esophageal balloon dilatation. In the multivariate analysis, independent prognostic factors of the positive esophageal balloon dilatation effect were age (incidence rate ratio [IRR]: -0.01; 95% confidence interval [CI]: -0.01, -0.002), shape of stricture (IRR: -0.54; 95% CI: -0.91, -0.18) and number of esophageal balloon dilatation sessions (IRR, -0.10; 95% CI: -0.14, -0.18).Repeated esophageal balloon dilatation, older age and eccentric stricture shape are associated with poor response to esophageal balloon dilatation in children with anastomotic strictures after esophageal atresia repair.

Patients with craniopharyngioma are susceptible to autonomic dysfunction as a result of hypothalamic damage. We evaluated indices of heart rate variability (HRV) in patients with childhood-onset craniopharyngioma to investigate autonomic function and its relationship with components of the metabolic syndrome (MetS). This cross-sectional, case-only study included 53 patients (10–30 years of age). We measured the standard deviation of all normal R-R intervals (SDNN) and total power indicating overall HRV, the root-mean square of the difference of successive R-R intervals (RMSSD) and high frequency indicating parasympathetic modulation, and low frequency. These indices were compared according to the presence of the MetS. During the mean 10.8 years of follow-up, 25% of patients were diagnosed with the MetS. Patients with the MetS showed significantly lower levels of SDNN (29.0 vs. 40.6 ms), total power (416.1 vs. 1129.6 ms2), RMSSD (20.1 vs. 34.5 ms), high frequency (94.7 vs. 338.5 ms2), and low frequency (94.5 vs. 289.4 ms2) than those without (p

To evaluate the clinical usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in children and young adults with Crohn’s disease. From August 2017 to October 2018, 30 patients with Crohn’s disease (21 males and 9 females; mean age 15.1 ± 2.5 years) underwent DCE-MRI with MRI enterography. We assessed the endoscopic finding, pediatric Crohn’s disease activity index (PCDAI), C-reactive protein (CRP) level (mg/dL), Crohn’s disease MR index (CDMI) score, and the perfusion parameters of DCE-MRI (Ktrans, Kep, and Ve) at the ileocecal region between the inactive and active groups based on the histopathologic status. The active Crohn’s disease group showed higher PCDAI, CRP, and CDMI scores than the inactive group (22.2 ± 18.8 vs. 6.3 ± 6.4, p = 0.027; 1.32 ± 1.79 vs. 0.10 ± 0.13, p = 0.005; 7.4 ± 3.9 vs. 4.5 ± 3.0, p = 0.047, respectively). The active Crohn’s disease group showed a higher Ktrans value than the inactive group (0.31 ± 0.12 vs. 0.16 ± 0.46 min−1, p = 0.002). Endoscopic finding; PCDAI, CRP, and CDMI scores; and Ktrans value were significant parameters in the identification of the active Crohn’s disease (p = 0.002, p

Hypothalamic damage may increase the risk of adulthood obesity and cardiovascular disease in craniopharyngioma. We evaluated the effects of hypothalamic involvement (HI) and growth hormone (GH) discontinuation on cardiovascular risk factors during the transition period in patients with childhood-onset craniopharyngioma.Thirty-three patients (17 males, 16 females) underwent retesting for adult GH deficiency (GHD) in 2005-2020 at Seoul National University Children's Hospital. Postoperative HI was graded by Puget's criteria and data regarding GH replacement was collected. At retesting, body mass index (BMI), fasting blood glucose, insulin, high-density lipoprotein cholesterol (HDL-C), triglycerides, and blood pressure were assessed.The mean age of commencement and discontinuation of GH replacement for childhood GHD was 10.0 ± 3.6 and 15.3 ± 3.1 years, respectively. The mean age at retesting for adult GHD was 17.7 ± 2.5 years. When patients were categorized by post-GH discontinuation duration, those with durations6 months (n = 27) showed lower HDL-C levels than those6 months (p = 0.037). Patients with extensive HI (n = 16) showed higher BMI z-score than those with none or mild HI (p = 0.020). Both the extent of HI and longer post-GH discontinuation duration were significantly predictive for decreased HDL-C levels (p0.05, for both).The extent of HI and GH discontinuation duration during the transition period can increase cardiovascular risk in patients with childhood-onset craniopharyngioma.

To investigate the feasibility and safety of transradial cerebral angiography (TRCA) in comparison to transfemoral cerebral angiography (TFCA) in the pediatric population.We retrospectively reviewed pediatric patients who underwent TRCA between January 2019 and July 2020. Patients with TFCA experience were examined. Pre- and post-procedural Doppler ultrasonography was performed to evaluate TRCA complications. To evaluate differences in radiation exposure between TRCA and TFCA, we investigated the radiation dose, dose area product (DAP), fluoroscopy time, and examination time.Thirty-five patients (mean age, 13.8 years; 22 male) underwent TRCA, with 18 (mean age, 13.0 years; 10 male) experiencing TFCA. TRCA was successful in all cases without technical failure. Radiation exposure including radiation dose and DAP were significantly higher in the TRCA group (474.1 mGy and 8299.6 μGy mAlthough TRCA is a technically feasible and safe method in pediatric patients, high radiation exposure to TFCA must be considered. Therefore, it should be considered as an alternative method in those with unfavorable clinical situations for performing TFCA.Level 4, Case Series.

This study aimed to evaluate a deep learning model for generating synthetic contrast-enhanced CT (sCECT) from non-contrast chest CT (NCCT). A deep learning model was applied to generate sCECT from NCCT. We collected three separate data sets, the development set (n = 25) for model training and tuning, test set 1 (n = 25) for technical evaluation, and test set 2 (n = 12) for clinical utility evaluation. In test set 1, image similarity metrics were calculated. In test set 2, the lesion contrast-to-noise ratio of the mediastinal lymph nodes was measured, and an observer study was conducted to compare lesion conspicuity. Comparisons were performed using the paired t-test or Wilcoxon signed-rank test. In test set 1, sCECT showed a lower mean absolute error (41.72 vs 48.74; P P P P P P ≤ .001). Synthetic CECT generated from NCCT improves the depiction of mediastinal lymph nodes.

Primary enucleation is a life-saving treatment for advanced intraocular retinoblastoma, particularly in patients with poor visual potential and functional contralateral eyes. This single-center study presents the treatment outcomes of patients with unilateral retinoblastoma who received primary enucleation and adjuvant chemotherapy with cyclophosphamide, vincristine, doxorubicin, and intrathecal methotrexate (CVDM) between 2000 and 2020. Twenty patients were enrolled in the study. The median age at diagnosis was 26 months (range, 1–45). Eighteen patients (90%) were in group E and two (10%) were in group D, according to the intraocular classification of retinoblastoma guidelines. Excluding one patient with an inadequate specimen, 19 patients (95%) had optic nerve involvement (ONI) at least up to the lamina cribrosa. Eight patients (40%) had choroidal invasion in addition to ONI. Two patients (10%) were surgical resection margin positive. The overall and event-free survival rates were 100% and 95%, respectively, for a median follow-up duration of 102.24 months (range 24.2–202.9). There were no relapses or deaths due to any cause, but one patient developed secondary rhabdomyosarcoma 99.6 months after chemotherapy. Treatment was well tolerated, with minimal hematotoxicity and hepatotoxicity. CVDM as a post-enucleation chemotherapy for advanced intraocular retinoblastoma has excellent outcomes with tolerable toxicity. However, in line with updated treatment trends, further risk stratification and lowering the treatment intensity should be considered. Continued long-term follow-up is required to further determine late effects.

Currently, the prevention of recurrent immediate hypersensitivity reactions (HSRs) to contrast media (CM) requests premedication and changing the culprit contrast agent. However, strategies for the prevention of immediate HSRs to gadolinium-based magnetic resonance contrast agents (GBCAs) have not yet been established. This study aimed to evaluate the effectiveness of changing the contrast agent and single-dose premedication for HSR recurrence prevention in patients with a history of mild immediate HSR to GBCA.The outcomes of patients with mild immediate HSR to GBCA who subsequently underwent enhanced magnetic resonance imaging between October 2012 and July 2017 were analyzed. The institutional CM monitoring system was retrospectively reviewed, and data on the application of premedication and choice of CM were obtained. Gadolinium-based magnetic resonance contrast agents were classified into 3 classes according to their molecular structure (macrocyclic ionic, macrocyclic nonionic, and linear ionic). Intravenous chlorpheniramine 4 mg, 30 minutes before the GBCA administration, or intravenous methylprednisolone sodium succinate 40 mg plus chlorpheniramine 4 mg, 1 hour before the GBCA administration, was administrated as premedication regimen. Recurrence rates of immediate HSR were compared according to prevention strategies.A total of 185 patients with a history of mild immediate HSR to GBCA were re-exposed to GBCA 397 times during the study period. The overall recurrence rate was 19.6% (78/397). Changing the culprit GBCA significantly reduced the recurrence rate, compared with reusing the culprit GBCA (6.9%, 9/130 and 25.8%, 69/267; P0.001). The recurrence rate was lowest when the GBCA was changed to a different molecular structure class from the culprit agent, followed by changing to CM with the same molecular structure and reusing the culprit GBCA (6.2%, 7/113 vs 11.8%, 2/17 vs 25.8%, 69/267; P0.001 with χ test for trend). Single-dose premedication demonstrated no significant prophylactic effect on recurrence (20.4%, 17/98 vs 17.3%, 61/299 with and without premedication, respectively; P = 0.509). Premedication in addition to changing CM also showed no additional prophylactic effect (7.2%, 7/97 and 6.1%, 2/33, respectively; P = 0.821).Changing the CM from the culprit agent could reduce the chance of HSR recurrence in patients with prior mild immediate HSR to GBCA, especially when the CM was changed to one of a different molecular structure class. However, single-dose premedication administration did not show significant HSR recurrence rate difference.

Objectives The diagnostic role of an ultrasound (US) and plasma renin activity (PRA) combination is unknown, despite the usefulness of Doppler US as a screening tool for renovascular hypertension (RVHT). The purpose of this study was to evaluate the diagnostic usefulness of US for RVHT in children stratified according to PRA. Methods We identified 336 children who underwent renal Doppler US examinations for hypertension and divided them into a high-renin group (n = 177) and a normal-renin group (n = 159) based on PRA and stratified them by age. The Doppler US findings were retrospectively reviewed, and computed tomographic angiography (CTA) for the same children was used as the reference standard. Results In the high-renin group, 36 patients had positive Doppler US findings that were confirmed by CTA in 32 cases. The sensitivity and specificity values for Doppler US in the high-renin group were 84.2% and 93.6%, respectively. In the normal-renin group, 10 patients had positive Doppler US findings; these positive findings were confirmed by CTA in 9 cases. The sensitivity and specificity values for US in the normal-renin group were 100.0% and 100.0%. There were anatomic variations (n = 3) and segmental artery stenosis (n = 2) among the cases with false-negative US findings, which were confirmed by CTA. Conclusions If patients have high PRA, a Doppler US examination should be performed with caution to avoid false-negative detection. If patients have normal PRA, renal Doppler US might be adequate for diagnosis of RVHT to avoid unnecessary CTA.

Background: The guideline for managing pediatric thyroid nodules has not been established. We investigated the appropriateness of the Korean Society of Thyroid Radiology (KSThR) guidelines and the ...

Purpose: This study aimed to assess the feasibility of shear-wave elastography (SWE) for assessing the testicular involvement of hematologic malignancies in children and young adults.Methods: Eight patients (mean age, 11.0 years; range, 0.8 to 20 years) with biopsy-confirmed testicular involvement of hematologic malignancy between January 2018 and December 2020 were retrospectively evaluated. Multiparametric ultrasound examinations, including grayscale, color Doppler ultrasonography (CDUS), and SWE, were performed. Stiffness was measured in the involved testicular area and contralateral normal parenchyma. If there was bilateral testicular involvement, the stiffness of the involved area and the adjacent normal echoic parenchyma was measured on one testis. The Mann-Whitney U test was used to compare stiffness values.Results: On grayscale, the testicular lesions were noted as a solitary mass in one patient, multiple lesions in four patients, and diffuse involvement in three patients. On CDUS and SWE, all patients demonstrated increased vascularity, and the stiffness of the involved area was higher than the values of normal parenchyma (the involved area vs. normal parenchyma, 11.6 kPa [3.9-20.2 kPa] vs. 2.9 kPa [1.1-3.7 kPa], P=0.003). The ratio of stiffness between the involved area and normal parenchyma was 3.4, ranging from 1.9 to 5.1. One patient showed decreased stiffness on follow-up SWE after treatment (affected testis vs. normal testis: initial, 13.8 vs. 3.2 kPa; 1 year later, 2.2 vs. 2.4 kPa).Conclusion: Increased testicular stiffness on SWE in children and young adults with hematologic malignancies suggests the possibility of testicular involvement.

Objective To describe the anatomic locations and imaging features of posterior lung herniation in unilateral pulmonary agenesis and aplasia, focusing on radiograph-CT/MRI correlation. Materials and methods A total of 10 patients (seven with pulmonary agenesis and three with pulmonary aplasia, male: female = 1:9, mean age 7.3 years, age range from 1 month to 20 years) were included. Chest radiographs (n = 9), CT (n = 9), and MRI (n = 1) were reviewed to assess the type of lung underdevelopment, presence of anterior and posterior lung herniation, bronchus origin, supplying artery, and draining vein of the herniated lung. Results Pulmonary agenesis/aplasia more commonly affected the left lung (n = 7) than the right lung (n = 3). Anterior lung herniation was observed in nine of the 10 patients. Posterior lung herniation was observed in seven patients with left pulmonary agenesis/aplasia. Two patients showed posterior lung herniation crossing the midline but not beyond the aorta, and five patients showed the posteriorly herniated right lower lobe crossing the midline to extend into the left hemithorax farther beyond the descending thoracic aorta through the space between the esophagus and the aorta. This anatomical configuration resulted in a characteristic radiographic finding of a radiolucent area with a convex lateral border and a vertical medial border in the left lower lung zone, revealing a tongue-like projection on CT and MRI. Conclusion Posterior lung herniation occurs in unilateral left lung agenesis/aplasia. Approximately 70% of the cases of posterior lung herniation reveal a unique radiolucent tongue-like projection in the left lower lung zone on imaging studies, which is caused by the extension of the posteriorly herniated right lung farther beyond the descending aorta.

Purpose The purpose of this study was to identify imaging risk factors on contrast-enhanced hip MRI after closed reduction of developmental dysplasia of the hip (DDH) that could predict future development of avascular necrosis (AVN) of the femoral head. Materials and methods Fifty-eight infants (F: M = 53: 5, aged 3–18 months) who underwent immediate postoperative contrast-enhanced hip MRI after closed reduction of DDH were included in this study. Quality of reduction (concentric vs eccentric reduction with or without obstacles), abduction angle of the hip, presence of ossific nucleus, and pattern of contrast enhancement of the femoral head were retrospectively evaluated on MRI. Interobserver agreement of contrast enhancement pattern on MRI were evaluated by two radiologists. Development of AVN was determined through radiographic findings at 1 year after reduction. Results AVN of the femoral head developed in 13 (22%) of 58 patients. Excessive abduction of the hip joint (OR 4.65, [95% CI 1.20, 18.06] and global decreased enhancement of the femoral head (OR 71.66, [95% CI 10.54, 487.31]) exhibited statistically significant differences between the AVN and non-AVN groups (P < 0.05). Eccentric reduction (P = 0.320) did not show statistically significant difference between two groups and invisible ossific nucleus (P = 0.05) showed borderline significance. Multi-variable logistic regression indicated that global decreased enhancement of the femoral head was a significant risk factor of AVN (OR 27.92, 95% CI [4.17, 350.18]) (P = 0.0031). Interobserver agreement of contrast enhancement pattern analysis and diagnosis of AVN were good (0.66, 95% CI [0.52, 0.80]). Conclusion Contrast-enhanced hip MRI provides accurate anatomical assessment of the hip after closed reduction of DDH. Global decreased enhancement of the femoral head could be used as a good predictor for future development of AVN after closed reduction of DDH.

A cerebral arteriovenous malformation (AVM) is a congenital and static disease. However, there are increasing reports of acquired AVMs. The pathophysiology of an acquired AVM has not been fully elucidated but the suggested pathophysiology is a combination of genetic abnormalities and inflammatory cytokines caused by previous brain insults. We report a patient who developed an acquired AVM after the treatment for a brain abscess. She underwent Gamma Knife surgery to treat the acquired AVM. It is necessary to understand the characteristics of acquired AVMs and to further research acquired AVMs.

Juvenile xanthogranuloma (JXG) is a type of non-Langerhans cell histiocytosis that most commonly manifests as a solitary cutaneous lesion of the head and neck in children. Intracranial JXG is extremely rare. Although it is widely known that JXG skin lesions gradually disappear over time without treatment, treatment guidelines for intracranial JXG have not been established. It is very difficult to predict whether an intracranial lesion is JXG with only a pre-operative imaging work-up without pathologic confirmation. We report a case of the youngest, a 3-month-old male infant with an intracranial extra-axial mass with rapid growth for 2 months. Additionally, we suggest characteristic MRI findings for intracranial extra-axial JXG of a low T2 signal and a kidney bean shape.

Background Central nervous system germ cell tumors (CNS GCTs) are a heterogeneous group of brain tumors, which are more common in Asian countries. There have been different therapeutic strategies in treating germinoma and non-germinomatous germ cell tumors (NGGCT), depending on prognosis. Moreover, long-term follow up should be emphasized due to higher late complication rates. Here, we investigated long-term outcomes and complication profiles of 127 CNS GCT patients who received uniform upfront chemotherapy. Methods We retrospectively evaluated outcomes of CNS GCT patients treated in Seoul National University Children’s Hospital from August 2004 to April 2019. Patients were classified as low risk (LR) or high risk (HR) based on pathologic diagnosis and tumor markers. Most patients received upfront systemic chemotherapy with carboplatin, cyclophosphamide, etoposide, and/or bleomycin, followed by either proton or photon radiation therapy according to patients’ choice. Results The median age at diagnosis was 11.9 (range, 3.8–25.1) years, and 54.3% of patients were LR. Photon and proton radiation therapy were administered to 73.2 and 25.2% of patients, respectively. In both LR and HR groups, there were no significant differences in survival between photon and proton radiation therapy. The 10-year relapse incidences were 9.3 and 5.6% in the LR and HR groups, respectively. All recurrences, except one, were local relapse. Six secondary malignancies occurred; the 10-year incidences of secondary malignancy were 2.2 and 7.6% in the LR and HR groups, respectively. The 10-year overall survival rates were 98.3 ± 1.7 and 91.8 ± 3.9% in the LR and HR groups, respectively. In a subgroup analysis of HR group, pathologically diagnosed NGGCT patients (n = 20) showed worse 10-year EFS (65.9 ± 11.9%, p p = 0.024) rates compared to other HR patients who were not pathologically diagnosed or were confirmed as germinoma with elevated tumor markers. All mortalities were related to disease progression or secondary malignancy. Conclusion The strategy of treating CNS GCTs with upfront chemotherapy according to risk groups resulted in good clinical outcomes and acceptable relapse incidence. However, further modification in the definition of the HR group is needed to reduce long-term complications.

We investigated the feasibility of free-breathing modified Look-Locker inversion recovery (MOLLI) sequence for measuring hepatic T1 values in children and young adults. To investigate the accuracy and the reproducibility of the T1 maps, a phantom study was performed with 12 different gadoterate meglumine concentrations and the T1 relaxation times of phantoms measured with the MOLLI sequence were compared against those measured with three different sequences: spin-echo inversion recovery, variable flip angle (VFA), and VFA with B1 correction. To evaluate the feasibility of free-breathing MOLLI sequence, hepatic T1 relaxation times obtained by free-breathing and breath-hold technique in twenty patients were compared. The phantom study revealed the excellent accuracy and reproducibility of MOLLI. In twenty patients, the mean value of hepatic T1 values obtained by free-breathing (606.7 ± 64.5 ms) and breath-hold (609.8 ± 64.0 ms) techniques showed no significant difference (p > 0.05). The Bland–Altman plot between the free-breathing and breath-hold revealed that the mean difference of T1 values was − 3.0 ms (− 0.5%). Therefore, T1 relaxation times obtained by MOLLI were comparable to the values obtained using the standard inversion recovery method. The hepatic T1 relaxation times measured by MOLLI technique with free-breathing were comparable to those obtained with breath-hold in children and young adults.

BACKGROUND. Hippocampal sclerosis (HS) is a leading cause of medically refractory temporal lobe epilepsy in children. The diagnosis is clinically important because most patients with HS have good p...

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous group of diseases with abnormal proliferation of lymphoid tissue and classical Hodgkin lymphoma (CHL) type PTLD is a very rare subtype. We describe a successfully diagnosed and treated CHL-PTLD stage IV pediatric patient, 8 years after liver transplantation. The patient was treated with standard CHL (Children's Cancer Group 5942 group 3) chemotherapy, rituximab and reduction of immunosuppressant. The patient remains in complete remission after 3 years with stable graft function. To our best knowledge, this is the first pediatric case report of a successfully treated stage IV CHL-PTLD after a liver transplant.

To evaluate the image quality of low iodine concentration, dual-energy CT (DECT) combined with a deep learning-based noise reduction technique for pediatric abdominal CT, compared with standard iodine concentration single-energy polychromatic CT (SECT).From December 2016 to May 2017, DECT with 300 mg•I/mL contrast medium was performed in 29 pediatric patients (17 boys, 12 girls; age, 2-19 years). The DECT images were reconstructed using a noise-optimized virtual monoenergetic reconstruction image (VMI) with and without a deep learning method. SECT images with 350 mg•I/mL contrast medium, performed within the last 3 months before the DECT, served as reference images. The quantitative and qualitative parameters were compared using paired t tests and Wilcoxon signed-rank tests, and the differences in radiation dose and total iodine administration were assessed.The linearly blended DECT showed lower attenuation and higher noise than SECT. The 60-keV VMI showed an increase in attenuation and higher noise than SECT. The combined 60-keV VMI plus deep learning images showed low noise, no difference in contrast-to-noise ratios, and overall image quality or diagnostic image quality, but showed a higher signal-to-noise ratio in the liver and lower enhancement of lesions than SECT. The overall image and diagnostic quality of lesions were maintained on the combined noise reduction approach. The CT dose index volume and total iodine administration in DECT were respectively 19.6% and 14.3% lower than those in SECT.Low iodine concentration DECT, combined with deep learning in pediatric abdominal CT, can maintain image quality while reducing the radiation dose and iodine load, compared with standard SECT.• An image noise reduction approach combining deep learning and noise-optimized virtual monoenergetic image reconstruction can maintain image quality while reducing radiation dose and iodine load. • The 60-keV virtual monoenergetic image reconstruction plus deep learning images showed low noise, no difference in contrast-to-noise ratio, and overall image quality, but showed a higher signal-to-noise ratio in the liver and a lower enhancement of lesion than single-energy polychromatic CT. • This combination could offer a 19.6% reduction in radiation dose and a 14.3% reduction in iodine load, in comparison with a control group that underwent single-energy polychromatic CT with the standard protocol.

OBJECTIVE. The aim of this study was to develop a low-dose radiography protocol for the neonatal ICU (NICU) using a new mobile digital radiography system with advanced denoising image processing and to evaluate the noninferiority of that protocol. SUBJECTS AND METHODS. In this prospective randomized study, 40 neonates in the NICU underwent radiography of the thorax and abdomen with two different mobile radiography units: conventional technique on one unit (50 kV, 1.6 mAs, and no additional filtration) and a new technique on another unit (54 kV, 0.1-mm Cu filtration). Three low-dose protocols for the second unit were developed in a phantom study: protocol A (100% equivalent dose with conventional protocol), protocol B (80% equivalent dose), and protocol C (64% equivalent dose). The noninferiority of each low-dose protocol was assessed by three independent readers using image quality criteria. RESULTS. Forty patients each underwent three pairs of radiography examinations (protocol A and the conventional protocol, protocol B and the conventional protocol, and protocol C and the conventional protocol), except one pair that did not include one image of the conventional protocol. The interrater reliability among the three readers was 0.91 (p < 0.001). Both of the low-dose protocols (B and C) were statistically noninferior to the conventional protocol with respect to overall image quality. Protocol B better depicted almost all anatomic landmarks and had better overall image quality than the conventional protocol. CONCLUSION. Using appropriate technique and acquisition factors, radiation dose can be lowered on a digital radiography system without significant effect on the image quality by adding filtrations and a new denoising technique.

Preoperative estimation of the insertion depth angle of cochlear implant (CI) electrodes is essential for surgical planning. The purpose of this study was to determine the cochlear size using preoperative CT and to investigate the correlation between cochlear size and insertion depth angle in morphologically normal cochlea.Thirty-five children who underwent CI were included in this study. Cochlear duct length (CDL) and the diameter of the cochlear basal turn (distance A/B) on preoperative CT and the insertion depth angle of the CI electrode on postoperative radiographs were independently measured by two readers. Correlation between cochlear size and insertion depth angle was evaluated. Interobserver agreement was calculated using the intraclass correlation coefficient (ICC).The mean CDL, distance A, and distance B of 70 ears were 36.20 ± 1.57 mm, 8.67 ± 0.42 mm, and 5.73 ± 0.32 mm, respectively. The mean insertion depth angle was 431.45 ± 38.42°. Interobserver agreements of CDL, distance A/B, and insertion depth angle were fair to excellent (ICC 0.864, 0.862, 0.529, and 0.958, respectively). Distance A (r = - 0.7643) and distance B (r = - 0.7118) showed a negative correlation with insertion depth angle, respectively (p0.0001). However, the correlation between CDL and insertion depth angle was not statistically significant (r = - 0.2333, p0.05).The CDL and cochlear distance can be reliably obtained from preoperative CT. Distance A can be used as a predictive marker for estimating insertion depth angle during CI surgery.

Background The image quality of abdominal magnetic resonance imaging (MRI) in children who cannot hold their breath has been severely impaired by motion artifacts. Purpose To evaluate the usefulness of T1-weighted (T1W) BLADE MRI for axial abdominal imaging in children who cannot hold their breath. Material and Methods Two different BLADE sequences, with and without an inversion recovery (IR-BLADE), were compared to conventional turbo-spin echo (TSE) with a high number of excitations in 18 consecutive patients who cannot hold their breath. Overall image quality, motion artifact, radial artifact, hepatic vessel sharpness, renal corticomedullary differentiation, and lesion conspicuity were retrospectively assessed by two radiologists, using 4- or 5-point scoring systems. Signal variations of each sequence were measured for a quantitative comparison. The acquisition times of the three sequences were compared. Results IR-BLADE and BLADE showed significantly improved overall image quality and reduced motion artifact compared with TSE. IR-BLADE showed significantly better hepatic vessel sharpness and corticomedullary differentiation compared to both BLADE and TSE. Radial artifacts were only observed on IR-BLADE and BLADE. In nine patients with lesions, there were no significant differences in lesion conspicuity among three sequences. Compared to TSE, both IR-BLADE and BLADE showed decreased signal variations in the liver and muscle, and an increased signal variation through air. The mean acquisition times for IR-BLADE, BLADE, and TSE were comparable. Conclusion Compared to the TSE sequence, T1W IR-BLADE for pediatric abdominal MRI resulted in improved image quality, tissue contrast with a diminished respiratory motion artifact, and a comparable acquisition time.

OBJECTIVE As the surgical burden of diseases grows higher than ever, the development of skilled surgeons and surgery teams is of fundamental importance. However, there is scarce evidence of the effectiveness of surgical training programs. Our study aims to evaluate the effectiveness of a global surgery fellowship program. DESIGN In 2018, Myanmar subspecialty surgeons were trained for a 3-month in tertiary hospital of Korea. We evaluated the reactions, learning, and transfer of the 11 trainees using Kirkpatrick's Evaluation Model. SETTING Myanmar and Korean tertiary hospital. PARTICIPANTS Eleven participants of fellowship from Myanmar. RESULTS Participants’ overall reaction scores were 4.45 ± 0.52 out of 5.00. Regarding overall competency, the trainees assessed themselves as at an “advanced beginner level” (3.63 ± 1.38 out of 10.00) at the beginning and at a “competent level” (5.40 ± 1.70 out of 10.00) after the training (p for difference = 0.014). The trainees stated that their transfer in clinical practice was between “quite applicable” and “I am very sure that I can do this” (3.39 ± 0.61 out of 4.00). Their transfer in education was second, ranked around “quite applicable” (3.21 ± 0.77 out of 4.00), and their transfer in research was last and ranked “applicable, but just a little” (2.81 ± 0.67 out of 4.00). However, in our online survey, native and foreign trainers had mixed opinions about the transfer of training and were not entirely confident in the trainees’ competency. Trainees felt that there were multifactorial challenges for transfer and cited infrastructure, facilities, human resources, perioperative care, and financing. CONCLUSIONS Surgical trainees reported high-level satisfaction and increased knowledge after training. However, further onsite surgical experiences are necessary for a successful transfer to the real setting. Challenges for such transfers were multifactorial, and surgical care must be systemically strengthened.

To develop and evaluate a deep learning-based artificial intelligence (AI) model for detecting skull fractures on plain radiographs in children.This retrospective multi-center study consisted of a development dataset acquired from two hospitals (n = 149 and 264) and an external test set (n = 95) from a third hospital. Datasets included children with head trauma who underwent both skull radiography and cranial computed tomography (CT). The development dataset was split into training, tuning, and internal test sets in a ratio of 7:1:2. The reference standard for skull fracture was cranial CT. Two radiology residents, a pediatric radiologist, and two emergency physicians participated in a two-session observer study on an external test set with and without AI assistance. We obtained the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity along with their 95% confidence intervals (CIs).The AI model showed an AUROC of 0.922 (95% CI, 0.842-0.969) in the internal test set and 0.870 (95% CI, 0.785-0.930) in the external test set. The model had a sensitivity of 81.1% (95% CI, 64.8%-92.0%) and specificity of 91.3% (95% CI, 79.2%-97.6%) for the internal test set and 78.9% (95% CI, 54.4%-93.9%) and 88.2% (95% CI, 78.7%-94.4%), respectively, for the external test set. With the model's assistance, significant AUROC improvement was observed in radiology residents (pooled results) and emergency physicians (pooled results) with the difference from reading without AI assistance of 0.094 (95% CI, 0.020-0.168;A deep learning-based AI model improved the performance of inexperienced radiologists and emergency physicians in diagnosing pediatric skull fractures on plain radiographs.