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Crohn's disease is a chronic idiopathic inflammatory disease of the intestines characterized by frequent relapse and remission. It often develops in children and adolescents, who are vulnerable to repeated exposure to ionizing radiations. Magnetic resonance enterography (MRE) is an increasingly important radiation-free imaging modality that is used to evaluate pediatric patients with Crohn's disease. MRE can evaluate extraluminal and extraintestinal abnormalities as well as the status of the bowel wall. In addition, MRE has an advantage in the evaluation of the small bowel involvement. MRE can be used for the initial diagnosis of Crohn's disease, and can aid in the assessment of disease activity and complications such as penetrating and fibrostenotic diseases. The aims of this article are to review the MRE technique for obtaining diagnostic and high-quality images and to discuss interpretations of imaging findings in patients with Crohn's disease. [ABSTRACT FROM AUTHOR]

Congenital esophageal stenosis (CES) can be associated with esophageal atresia/tracheoesophageal fistula (EA/TEF). Because there are a variety of degrees of obstruction and symptoms of CES, it is frequently difficult to make a pre- and post-operative diagnosis of the distal CES associated with EA/TEF. To evaluate the clinical and radiologic features of congenital esophageal stenosis associated with esophageal atresia/tracheoesophageal fistula. We retrospectively reviewed postoperative esophagograms and medical records of 187 children (107 boys, 80 girls) who had primary repair of EA/TEF from 1992 to 2009 at our institution. We evaluated the incidence of CES, clinical findings, radiologic features and management of CES in these children. CES was diagnosed in 22 of 187 EA/TEF children (12%); one child had double CES lesions, for a total of 23 lesions. Ten of those 22 children (45%) had presented with significant symptoms of esophageal obstruction. The diagnosis of CES was delayed in 10 children (45%) until 1–10 years of age. On esophagogram, CES ( n = 23) was located in the distal esophagus ( n = 20, 87%) or mid-esophagus ( n = 3, 13%). The degree of stenosis was severe ( n = 6, 26%), moderate ( n = 10, 43%), or mild ( n = 7, 30%). Eight children, including two with unsuccessful esophageal balloon dilatation of CES, were treated surgically. Histologic examination revealed tracheobronchial remnant ( n = 7) or fibromuscular hyperplasia ( n = 1). One child with surgically treated CES developed achalasia at the age of 3 years 9 months. Esophagography after EA/TEF repair should be performed with a high index of suspicion for the presence of distal CES, because the diagnosis and adequate management of CES can often be delayed. [ABSTRACT FROM AUTHOR]

Background: Nutcracker syndrome is characterized by gross haematuria caused by left renal vein (LRV) entrapment. Objective: To assess the role of LRV ultrasonography in the diagnosis of the nutcracker syndrome in children. Materials and methods: Twelve children (eight male, four female; mean age 12.8 years) with venographically confirmed nutcracker syndrome (LRV-IVC pressure gradient ≥3 mm Hg) underwent LRV sonography including Doppler spectral analysis ( n=7). The diameter and peak velocity (PV) were measured at two sites of the LRV (renal hilum and aortomesenteric portion). The US findings of nutcracker syndrome were compared with those of 20 control subjects using the t-test. We identified the optimal cut-off value of the US parameters for the diagnosis of the nutcracker syndrome using ROC analysis. Results: The PV at the aortomesenteric portion and the ratio of the PV between the two measured points showed significant differences between the two groups ( P<0.0001). The optimum cut-off values were found to be 4.7 for the PV ratio (sensitivity 100%, specificity 90%, accuracy 93%), and 93 cm/s for the PV at the aortomesenteric portion (sensitivity 100%, specificity 85%, accuracy 89%). Conclusion: LRV sonography, including Doppler spectral analysis, can demonstrate LRV entrapment haemodynamically. [ABSTRACT FROM AUTHOR]

Background: Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in neonatal intensive care units. Ultrasonographic findings in early-stage NEC have not been described. Objective: To assess the diagnostic value of ultrasonography for the diagnosis and monitoring of patients with NEC. Materials and methods: We evaluated the sonographic findings of early stages of NEC in 40 neonates who were clinically diagnosed with NEC when they were 2–28 days old. Their average gestational age was 32 weeks, and their mean weight was 1,850 g. All of the patients showed signs of bowel distention on abdominal radiography, with no evidence of pneumatosis intestinalis. We performed bowel sonography in all patients ( n = 40), as well as in ten healthy neonates who served as a control group. The studies were conducted with a 10-MHz linear transducer from February 2003 to January 2004. We evaluated the echogenicity of the bowel wall, involved region, ascites, and portal venous gas at both initial and follow-up examinations. We divided the patients into two groups according to the bowel wall echogenicity pattern, group I with echogenic dots in the bowel wall and group II with dense granular echogenicities in the bowel wall. In order to identify any correlations between the ultrasonography and clinical findings, we evaluated the duration of parenteral feeding (NPO) in each group and compared two groups by means of a statistical analysis (Mann–Whitney test). Results: All of the neonates in the control group ( n = 10) presented normal bowel wall echogenicity; the patients with NEC presented echogenic dots in 16 patients (40%) and dense granular echogenicities in 24 patients (60%). Portal venous gas was absent in all patients. On the follow-up examinations, the echogenicity of the bowel wall and ascites decreased in 37 patients (93%). The duration of NPO was 11.1 ± 6.6 days in group I and 16.5 ± 7.2 days in group II ( P < 0.05). Conclusion: Echogenic dots or dense granular echogenicities in the bowel wall can be seen in patients with early-stage NEC. Bowel sonography can be helpful for the early diagnosis and monitoring of patients with NEC. [ABSTRACT FROM AUTHOR]

Widespread use of fetal ultrasonography is accompanied by more frequent detection of antenatal hydronephrosis. Therefore, sonographic evaluation of neonates with a history of antenatal hydronephrosis is becoming more widespread. As an initial postnatal non-invasive imaging modality, ultrasonography is used to screen for persistence of hydronephrosis, determine the level and severity of obstruction, and contribute to appropriate diagnosis and treatment. This review aims to provide a practical overview of the sonographic evaluation of neonatal hydronephrosis and to describe the sonographic findings of conditions associated with hydronephrosis in the newborn. [ABSTRACT FROM AUTHOR]

Esophageal candidiasis is commonly seen in immunocompromised patients; however, candida esophagitis induced stricture is a very rare complication. We report the first case of esophageal stricture secondary to candidiasis in a glycogen storage disease (GSD) 1b child. The patient was diagnosed with GSD type 1b by liver biopsy. No mutation was found in the G6PC gene, but SLC37A4 gene sequencing revealed a compound heterozygous mutation (p.R28H and p.W107X, which was a novel mutation). The patient's absolute neutrophil count was continuously under 1,000/µL when he was over 6 years of age. He was admitted frequently for recurrent fever and infection, and frequently received intravenous antibiotics, antifungal agents. He complained of persistent dysphagia beginning at age 7 years. Esophageal stricture and multiple whitish patches were observed by endoscopy and endoscopic biopsy revealed numerous fungal hyphae consistent with candida esophagitis. He received esophageal balloon dilatation four times, and his symptoms improved. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Sepsis predisposes full-term infants to necrotizing enterocolitis (NEC). As such, experimental induction of NEC was applied to a sepsis model to evaluate the potential role of US in the early diagnosis of NEC in full-term infants. Objective: To evaluate the resistive index (RI) of the superior mesenteric artery (SMA) on Doppler sonography in experimentally induced sepsis and correlate it with the pathological findings. Materials and methods: Fifteen 1-week-old New Zealand white rabbits (control group n = 3, sepsis group n = 12) were used in this study. We injected 1 mg/kg of E. coli O55-B5 lipopolysaccharide (LPS) into 12 rabbits to induce sepsis. Then we conducted grayscale evaluation of the caliber of the abdominal aorta as well as bowel wall thickness and echogenicity. In addition, we measured peak systolic and end-diastolic velocities and SMA RI on Doppler sonography. Pathological findings were analyzed and correlated with RI readings. Peak systolic and end-diastolic velocities and SMA RI values were analyzed statistically at each hour using the Wilcoxon rank sum test; the control and sepsis groups were compared using the Mann-Whitney test. Results: The bowel wall thickness in the sepsis group was significantly increased after LPS injection. The caliber of the abdominal aorta in the sepsis group was significantly decreased after LPS injection. There were echogenic foci (<10 in axial plane) in the bowel wall after LPS injection. Peak systolic velocity in the sepsis group was not significantly changed, but end-diastolic velocity was decreased. SMA RIs in the sepsis group were significantly increased post-LPS injection from baseline. In the control group there were no significant changes in bowel wall thickness, abdominal aorta caliber, bowel wall echogenicity or peak systolic and end-diastolic velocities and RIs. Pathologically, eight of the 12 rabbits in the sepsis group showed grade 1 intestinal injury, three showed grade 2 injury and one showed grade 3 injury. SMA RIs were higher in grades 2 and 3 than in grade 1 when measured at 2 h and 4 h. Conclusion: Sepsis caused necrotic injury in the animal models, and these findings were accompanied by significant changes on Doppler US. These findings could facilitate early detection of intestinal injury in septic infants with NEC. [ABSTRACT FROM AUTHOR]

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 P<0.001), whereas the Emean at rest and volume asymmetry were not (all P>0.05). 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. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate the usefulness of the stability index (SI) in liver stiffness measurements using shear wave elastography (SWE) in children. Methods: A total of 29 children and young adults (mean age, 16.1 years; range, 8 to 28 years; 11 boys and 18 girls) who underwent liver stiffness measurements using SWE under freebreathing and breath-holding conditions were included in our study. Ten SWE measurements were acquired in each of four groups: free-breathing and breath-holding, and with and without using the SI. The failure rate of acquisition of SI values over 90% was calculated in each group. To evaluate variability in the SWE measurements, the standard deviation, coefficient of variation, and percentage of unreliable measurements were compared. Intraobserver agreement and the optimal minimal number of measurements were calculated using intraclass correlation coefficients. Results: A failure to acquire SI values over 90% was observed in 17% of the scans in the freebreathing group and in 7% of the scans in the breath-holding group. In both groups, utilizing the SI led to a significantly lower standard deviation and coefficient of variation. When using the SI, the percentage of unreliable measurements decreased from 16.7% to 8.3% in the free-breathing group and 14.8% to 0% in the breath-holding group. With the use of the SI, intraobserver agreement increased and the optimal minimal number of repeated measurements decreased in both the free-breathing and breath-holding groups. Conclusion: Utilization of the SI in the measurement of liver SWE in children reduced measurement variability and increased reliability in both free-breathing and breath-holding conditions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to identify ultrasonographic features that can be used to differentiate between thyroglossal duct cysts (TGDCs) and dermoid cysts (DCs). Methods: We searched surgical pathology reports completed between January 2004 and October 2015 and identified 66 patients with TGDCs or DCs who had undergone preoperative ultrasonography. The ultrasound images were reviewed by two radiologists who were blinded to the pathological diagnosis. They evaluated the following parameters: dimensions, shape, margin, location in relation to the midline, level in relation to the hyoid bone, attachment to the hyoid bone, the depth of the lesion in relation to the strap muscles, internal echogenicity, internal echogenic dots, multilocularity, the presence of a longitudinal extension into the tongue base, posterior acoustic enhancement, the presence of internal septae, and intralesional vascularity. Results: There were 50 TGDCs and 16 DCs. TGDCs were significantly more likely than DCs to have an irregular shape, an ill-defined margin, attachment to the hyoid bone, an intramuscular location, heterogeneous internal echogenicity, multilocularity, and longitudinal extension into the tongue base. Conclusion: Ultrasound findings may inform the differential diagnosis between TGDCs and DCs. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate impact of 3-dimensional cranial ultrasonography (3DUS) on reinterpretation of cranial ultrasonography images in neonates in comparison with 2-dimensional cranial ultrasonography (2DUS). Methods: We retrospectively enrolled 50 young infants who simultaneously underwent both 2DUS and 3DUS scanning from February to March 2015. Two pediatric radiologists independently reviewed both scans for overall image quality on a 5-point scale. Five features were evaluated in both scans: the presence of germinal matrix hemorrhage (GMH), intraventricular hemorrhage (IVH), ventriculomegaly (VM), abnormality of periventricular echogenicity (PVE), and focal parenchymal lesions (FL). The concordance rate between the two scanning modes was calculated. The confidence level for each finding on a 3-point scale and the scanning time were compared between the two scanning modes. Interobserver agreement was evaluated using kappa statistics. Results: Both scans demonstrated similar overall image quality in terms of reinterpretation (mean scores for 2DUS and 3DUS, 4.0±0.5 and 4.0±0.7 in reviewer 1, 3.9±0.6 and 4.0±0.8 in reviewer 2, respectively). GMH, IVH, VM, and FL showed perfect concordance, while PVE showed a concordance rate of 91.4% between the two modes by both reviewers. 3DUS was associated with a higher diagnostic confidence in the evaluation of GMH, IVH, and FL than 2DUS (P<0.05) for both reviewers. For PVE, 3DUS received a significantly higher confidence score than 2DUS from one of the reviewers. The mean scanning time for 2DUS and 3DUS was 92.75 seconds and 36 seconds, respectively. Interobserver agreement for qualitative scoring was almost perfect. Conclusion: In reinterpretation, 3DUS showed very high concordance with 2DUS and a similar image quality. 3DUS also increased diagnostic confidence for several image findings and significantly decreased scan time. [ABSTRACT FROM AUTHOR]

Patients with lysosomal acid lipase (LAL) deficiency and glycogen storage disease (GSD) demonstrated hepatomegaly and dyslipidemia. In our case, a 6-year-old boy presented with hepatosplenomegaly. At 3 years of age, GSD had been diagnosed by liver biopsy at another hospital. He showed elevated serum liver enzymes and dyslipidemia. Liver biopsy revealed diffuse microvesicular fatty changes in hepatocytes, septal fibrosis and foamy macrophages. Ultrastructural examination demonstrated numerous lysosomes that contained lipid material and intracytoplasmic cholesterol clefts. A dried blood spot test revealed markedly decreased activity of LAL. LIPA gene sequencing identified the presence of a novel homozygous mutation (p.Thr177Ile). The patient's elevated liver enzymes and dyslipidemia improved with enzyme replacement therapy. This is the first report of a Korean child with LAL deficiency, and our findings suggest that this condition should be considered in the differential diagnosis of children with hepatosplenomegaly and dyslipidemia. [ABSTRACT FROM AUTHOR]

Pulmonary alveolar proteinosis (PAP) is a rare disease in children characterized by intra-alveolar accumulation of surfactant proteins, which severely reduces gaseous exchange. Whole lung lavage (WLL) is the preferred technique for the treatment of severe PAP. Herein, we present a pediatric case of PAP treated with WLL. An 11-year-old boy was admitted with the chief complaint of a dry cough lasting 6 months. He developed symptoms of dyspnea on exertion and had difficulty in climbing stairs. He was ultimately diagnosed with PAP through video-assisted thoracoscopic lung biopsy. As first-line of treatment for PAP, he underwent therapeutic WLL for each of his lungs on separate days. After a brief recovery, his symptoms gradually worsened; therefore, he underwent a second WLL. This is the first pediatric case of PAP relapse despite successful WLL in Korea. [ABSTRACT FROM AUTHOR]

Background: With the emergence of macrolide resistance, concerns about the efficacy of macrolides for the treatment of Mycoplasma pneumoniae (MP) pneumonia in children have been raised. This study aimed to determine the effect of macrolide resistance on the outcome of children who were hospitalized with MP pneumonia.Methods: Between 2010 and 2015, we performed culture of MP from nasopharyngeal samples obtained from children who were hospitalized with pneumonia at five hospitals in Korea. Macrolide resistance was determined by the analysis of 23S rRNA gene transition and the minimal inhibitory concentrations of four macrolides. Medical records were reviewed to analyze the clinical response to treatment with macrolides.Results: MP was detected in 116 (4.8%) of the 2436 children with pneumonia. MP pneumonia was prevalent in 2011 and 2015. Of the 116 patients with MP pneumonia, 82 (70.7%) were macrolide-resistant. There were no differences in the age distribution, total duration of fever, and chest x-ray patterns between the macrolide-susceptible and macrolide-resistant groups. After macrolide initiation, mean days to defervescence were longer in the macrolide-resistant group than in macrolide-susceptible group (5.7 days vs. 4.1 days, P = 0.021). However, logistic regression analysis revealed that the presence of extrapulmonary signs (P = 0.039), homogeneous lobar consolidation (P = 0.004), or parapneumonic effusion (P < 0.001) were associated with fever duration of ≥7 days after the initiation of macrolides, regardless of macrolide resistance.Conclusions: This study demonstrated that fever duration in MP pneumonia was determined by the radiologic findings of chest x-ray, not by the presence of macrolide resistance. The results highlight the need for future studies to assess therapeutic benefit from macrolides in the treatment of children with MP pneumonia. [ABSTRACT FROM AUTHOR]

Neonatal hemochromatosis (NH) is a severe neonatal liver injury that is confirmed by extra-hepatic iron accumulation. Although a recent study described treating NH with exchange transfusions and intravenous immunoglobulin, liver transplantation should be considered for patients with severe liver failure that does not respond to other medical treatment. Herein, we report the case of a two-month-old female infant who presented with persistent ascites and hyperbilirubinemia. Her laboratory findings demonstrated severe coagulopathy, high indirect and direct bilirubin levels, and high ferritin levels. Abdominal magnetic resonance imaging presented low signal intensity in the liver on T2-weighted images, suggesting iron deposition. The infant was diagnosed with NH as a result of the clinical findings and after congenital infection and metabolic diseases were excluded. The infant was successfully treated with a living-donor liver transplantation. Living related liver transplantation should be considered as a treatment option for NH in infants. [ABSTRACT FROM AUTHOR]

Chronic granulomatous disease (CGD) is an inherited immunodeficient disease characterized by recurrent infections and granuloma formation. Granulomatous obstruction of esophagus is one of the rare complications of CGD. The use of steroids and antimicrobials for esophageal obstruction by granuloma in CGD patients has been controversial due to the possibility of concomitant inapparent infection. We report a case of esophageal obstruction in an 8-year-old CGD patient showing the poor response to antibiotics therapy. However, dramatic improvement of symptoms and radiologic findings of esophageal obstruction were achieved after steroid therapy. One month after discontinuation of steroid, esophageal obstruction recurred and the patient was re-treated with steroid. After that time, he experienced one more recurrence of esophageal obstruction. This symptom subsided after antibiotics therapy without steroid and he has been followed up to the present without further relapse. [ABSTRACT FROM AUTHOR]

Patients with complex congenital heart defects palliated by connecting the systemic veins directly to the pulmonary circulation are known to develop hepatopulmonary syndrome (HPS). Although rare, HPS can develop following the Fontan operation. To present and analyse the CT findings of HPS in patients with a Fontan circulation. From May to December 2005, six patients with HPS following the completion of a Fontan circulation were evaluated. CT findings were reviewed and were compared with angiographic findings. All six patients showed unilateral involvement. All patients except one had inferior vena cava (IVC) interruption with azygos continuation. CT scans showed abnormal vascular dilatation in one lung, and properly demonstrated the anatomy causing the hepatic venous blood to flow preferentially into one lung. These CT findings correlated well with the angiography findings. HPS that develops after the Fontan procedure is typically unilateral and is often associated with IVC interruption and azygos or hemiazygos continuation. CT demonstrates dilatation of pulmonary vessels in the affected lung and may be able to demonstrate the underlying anatomical cause for the predilection of hepatic venous flow to the contralateral lung. [ABSTRACT FROM AUTHOR]

We present two cases of granulocytic sarcoma of the cervical lymph nodes with central necrosis as an initial manifestation of childhood leukaemia, focusing on the imaging features. Recognition of the CT and MR imaging findings of granulocytic sarcoma involving the cervical lymph nodes assists the differential diagnosis of noninfective lymphadenopathy in children. [ABSTRACT FROM AUTHOR]

A correction to the article about magnetic resonance (MR) and computed tomography (CT) features describing central skull base lymphoma in children that was published in the 2008 issue is presented.