A preliminary study of shear-wave elastography for the evaluation of varicocele in adolescents and young adults

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.

Optimal Kiloelectron Volt for Noise-Optimized Virtual Monoenergetic Images of Dual-Energy Pediatric Abdominopelvic Computed Tomography: Preliminary Results

OBJECTIVE: To compare quantitative and qualitative image quality parameters in pediatric abdominopelvic dual-energy CT (DECT) using noise-optimized virtual monoenergetic image (VMI) and conventional VMI at different kiloelectron volt (keV) levels. MATERIALS AND METHODS: Thirty-six consecutive abdominopelvic DECT scans were retrospectively included. Noise-optimized VMI and conventional VMI were reconstructed at seven energy levels, from 40 keV to 100 keV at 10 keV intervals. The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of the liver, pancreas, and aorta were objectively measured and compared. Image quality was evaluated subjectively regarding image noise, image blurring of solid organ, bowel image quality and severity of beam-hardening artifacts. Optimal monoenergetic levels in keV for both algorithms were determined based on overall image quality score. RESULTS: The maximal CNR and SNR values for all investigated organs were observed at 40 keV in noise-optimized VMI (CNR and SNR of liver, pancreas, aorta in order [CNR; 20.93, 17.34, 46.75: SNR; 37.39, 33.80, 63.21]), at 60–70 keV and at 70 keV in conventional VMI (CNR; 8.12, 5.67, 15.97: SNR; 19.57, 16.66, 26.65). In qualitative image analysis, noise-optimized VMI and conventional VMI showed the best overall image quality scores at 60 keV and at 70 keV, respectively. Noise-optimized VMI at 60 keV showed superior CNRs, SNRs, and overall image quality scores compared to conventional VMI at 70 keV (p < 0.001). CONCLUSION: Optimal energy levels for noise-optimized VMI and conventional VMI were 60 keV and at 70 keV, respectively. Noise-optimized VMI shows superior CNRs, SNRs and subjective image quality over conventional VMI, at the optimal energy level.

Application of Vendor-Neutral Iterative Reconstruction Technique to Pediatric Abdominal Computed Tomography

OBJECTIVE: To compare image qualities between vendor-neutral and vendor-specific hybrid iterative reconstruction (IR) techniques for abdominopelvic computed tomography (CT) in young patients. MATERIALS AND METHODS: In phantom study, we used an anthropomorphic pediatric phantom, age-equivalent to 5-year-old, and reconstructed CT data using traditional filtered back projection (FBP), vendor-specific and vendor-neutral IR techniques (ClariCT; ClariPI) in various radiation doses. Noise, low-contrast detectability and subjective spatial resolution were compared between FBP, vendor-specific (i.e., iDose1 to 5; Philips Healthcare), and vendor-neutral (i.e., ClariCT1 to 5) IR techniques in phantom. In 43 patients (median, 14 years; age range 1–19 years), noise, contrast-to-noise ratio (CNR), and qualitative image quality scores of abdominopelvic CT were compared between FBP, iDose level 4 (iDose4), and ClariCT level 2 (ClariCT2), which showed most similar image quality to clinically used vendor-specific IR images (i.e., iDose4) in phantom study. Noise, CNR, and qualitative imaging scores were compared using one-way repeated measure analysis of variance. RESULTS: In phantom study, ClariCT2 showed noise level similar to iDose4 (14.68–7.66 Hounsfield unit [HU] vs. 14.78–6.99 HU at CT dose index volume range of 0.8–3.8 mGy). Subjective low-contrast detectability and spatial resolution were similar between ClariCT2 and iDose4. In clinical study, ClariCT2 was equivalent to iDose4 for noise (14.26–17.33 vs. 16.01–18.90) and CNR (3.55–5.24 vs. 3.20–4.60) (p > 0.05). For qualitative imaging scores, the overall image quality ([reader 1, reader 2]; 2.74 vs. 2.07, 3.02 vs. 2.28) and noise (2.88 vs. 2.23, 2.93 vs. 2.33) of ClariCT2 were superior to those of FBP (p 0.05). CONCLUSION: Vendor-neutral IR technique shows image quality similar to that of clinically used vendor-specific hybrid IR technique for abdominopelvic CT in young patients.

Arterial Spin Labeling MRI for Quantitative Assessment of Cerebral Perfusion Before and After Cerebral Revascularization in Children with Moyamoya Disease

OBJECTIVE: To determine the correlation between cerebral blood flow (CBF) on arterial spin labeling (ASL) MRI and the degree of postoperative revascularization assessed on digital subtraction angiography in children with moyamoya disease (MMD). MATERIALS AND METHODS: Twenty-one children (9 boys and 12 girls; mean age, 8.4 ± 3.6 years; age range, 3–16 years) with MMD who underwent both pseudocontinuous ASL MRI at 1.5T and catheter angiography before and after superficial temporal artery encephaloduroarteriosynangiosis were included in this retrospective study. The degree of revascularization in the middle cerebral artery (MCA) territory was evaluated on external carotid angiography and was graded on a 3-point scale. On ASL CBF maps, regions of interest were manually drawn over the MCA territory of the operated side at the level of the centrum semi-ovale and over the cerebellum. The normalized CBF (nCBF) was calculated by dividing the CBF of the MCA territory by the CBF of the cerebellum. Changes in nCBFs were calculated by subtracting the preoperative nCBF values from the postoperative nCBF values. The correlation between nCBF changes measured with ASL and the revascularization grade from direct angiography was evaluated. RESULTS: The nCBF value on the operated side increased after the operation (p = 0.001). The higher the degree of revascularization, the greater the nCBF change was: poor revascularization (grade 1), −0.043 ± 0.212; fair revascularization (grade 2), 0.345 ± 0.176; good revascularization (grade 3), 0.453 ± 0.182 (p = 0.005, Jockheere-Terpstra test). The interobserver agreement was excellent for the measured CBF values of the three readers (0.91–0.97). CONCLUSION: The nCBF values of the MCA territory obtained from ASL MRI increased after the revascularization procedure in children with MMD, and the degree of nCBF change showed a significant correlation with the degree of collateral formation evaluated via catheter angiography.

Accurate measurements of liver stiffness using shear wave elastography in children and young adults and the role of the stability index

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 free-breathing 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 free-breathing 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.

Comparison between 3-dimensional cranial ultrasonography and conventional 2-dimensional cranial ultrasonography in neonates: impact on reinterpretation

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.

Ultrasonographic features differentiating thyroglossal duct cysts from dermoid cysts

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.

Ultrasonography of hydronephrosis in the newborn: a practical review

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.

Erratum: Ultrasonographic Diagnosis of Biliary Atresia Based on a Decision-Making Tree Model

On page 1364, the fifth author's name has been incorrectly spelled.

Ultrasonographic Diagnosis of Biliary Atresia Based on a Decision-Making Tree Model

OBJECTIVE: To assess the diagnostic value of various ultrasound (US) findings and to make a decision-tree model for US diagnosis of biliary atresia (BA). MATERIALS AND METHODS: From March 2008 to January 2014, the following US findings were retrospectively evaluated in 100 infants with cholestatic jaundice (BA, n = 46; non-BA, n = 54): length and morphology of the gallbladder, triangular cord thickness, hepatic artery and portal vein diameters, and visualization of the common bile duct. Logistic regression analyses were performed to determine the features that would be useful in predicting BA. Conditional inference tree analysis was used to generate a decision-making tree for classifying patients into the BA or non-BA groups. RESULTS: Multivariate logistic regression analysis showed that abnormal gallbladder morphology and greater triangular cord thickness were significant predictors of BA (p = 0.003 and 0.001; adjusted odds ratio: 345.6 and 65.6, respectively). In the decision-making tree using conditional inference tree analysis, gallbladder morphology and triangular cord thickness (optimal cutoff value of triangular cord thickness, 3.4 mm) were also selected as significant discriminators for differential diagnosis of BA, and gallbladder morphology was the first discriminator. The diagnostic performance of the decision-making tree was excellent, with sensitivity of 100% (46/46), specificity of 94.4% (51/54), and overall accuracy of 97% (97/100). CONCLUSION: Abnormal gallbladder morphology and greater triangular cord thickness (> 3.4 mm) were the most useful predictors of BA on US. We suggest that the gallbladder morphology should be evaluated first and that triangular cord thickness should be evaluated subsequently in cases with normal gallbladder morphology.

Effect of Arterial Deprivation on Growing Femoral Epiphysis: Quantitative Magnetic Resonance Imaging Using a Piglet Model

OBJECTIVE: To investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion MRI for the evaluation of femoral head ischemia. MATERIALS AND METHODS: Unilateral femoral head ischemia was induced by selective embolization of the medial circumflex femoral artery in 10 piglets. All MRIs were performed immediately (1 hour) and after embolization (1, 2, and 4 weeks). Apparent diffusion coefficients (ADCs) were calculated for the femoral head. The estimated pharmacokinetic parameters (Kep and Ve from two-compartment model) and semi-quantitative parameters including peak enhancement, time-to-peak (TTP), and contrast washout were evaluated. RESULTS: The epiphyseal ADC values of the ischemic hip decreased immediately (1 hour) after embolization. However, they increased rapidly at 1 week after embolization and remained elevated until 4 weeks after embolization. Perfusion MRI of ischemic hips showed decreased epiphyseal perfusion with decreased Kep immediately after embolization. Signal intensity-time curves showed delayed TTP with limited contrast washout immediately post-embolization. At 1-2 weeks after embolization, spontaneous reperfusion was observed in ischemic epiphyses. The change of ADC (p = 0.043) and Kep (p = 0.043) were significantly different between immediate (1 hour) after embolization and 1 week post-embolization. CONCLUSION: Diffusion MRI and pharmacokinetic model obtained from the DCE-MRI are useful in depicting early changes of perfusion and tissue damage using the model of femoral head ischemia in skeletally immature piglets.

Nasopharyngeal Carcinoma in Children and Adolescents: Single Institution Study / 임상소아혈액종양

BACKGROUND: Nasopharyngeal carcinoma (NPC) is very rare in children and adolescents. The aim of this study was to evaluate clinical characteristics and treatment outcomes of pediatric NPC. METHODS: Medical records of 9 patients treated for NPC at the Seoul National University Children's Hospital between 1988 and 2012 were analyzed retrospectively. RESULTS: The median age at diagnosis was 11 years (range, 9-13 years). One patient had stage II disease, 3 had stage III disease, and 5 had stage IV disease. The histologic subtypes were undifferentiated carcinoma and squamous cell carcinoma in 7 and 2 patients, respectively. All patients were initially treated with cisplatin (100 mg/m2 intravenous [IV] every 4 weeks for 4-6 months), bleomycin (15 unit/m2 IV every 1 weekx7), and fluorouracil (1,000 mg/m2 IV every 4 weeks for 1 year). Eight patients received radiotherapy with doses of 45-59.4 Gy at the primary site and neck nodes. Seven patients (77.8%) achieved complete remission, 1 (11.1%) achieved partial remission, and 1 (11.1%) showed disease progression. Six patients developed fluorouracil-related neurotoxicity; the regimen was changed to cisplatin, epirubicin, and bleomycin in five of the 6 patients. One patient died of progressive disease without responding to treatment. Treatment-related mortality occurred in 1 patient owing to septic shock. Secondary osteosarcoma developed in 1 patient 6 years after treatment. The overall survival was 77.8%, with a median follow-up of 40.8 months (range, 4.5-287.6 months). CONCLUSION: Children and adolescents with advanced NPC treated with combined chemotherapy and radiotherapy have a good survival rate.

Nasopharyngeal Carcinoma in Children and Adolescents: Single Institution Study / 임상소아혈액종양

BACKGROUND: Nasopharyngeal carcinoma (NPC) is very rare in children and adolescents. The aim of this study was to evaluate clinical characteristics and treatment outcomes of pediatric NPC.METHODS: Medical records of 9 patients treated for NPC at the Seoul National University Children's Hospital between 1988 and 2012 were analyzed retrospectively.RESULTS: The median age at diagnosis was 11 years (range, 9-13 years). One patient had stage II disease, 3 had stage III disease, and 5 had stage IV disease. The histologic subtypes were undifferentiated carcinoma and squamous cell carcinoma in 7 and 2 patients, respectively. All patients were initially treated with cisplatin (100 mg/m2 intravenous [IV] every 4 weeks for 4-6 months), bleomycin (15 unit/m2 IV every 1 weekx7), and fluorouracil (1,000 mg/m2 IV every 4 weeks for 1 year). Eight patients received radiotherapy with doses of 45-59.4 Gy at the primary site and neck nodes. Seven patients (77.8%) achieved complete remission, 1 (11.1%) achieved partial remission, and 1 (11.1%) showed disease progression. Six patients developed fluorouracil-related neurotoxicity; the regimen was changed to cisplatin, epirubicin, and bleomycin in five of the 6 patients. One patient died of progressive disease without responding to treatment. Treatment-related mortality occurred in 1 patient owing to septic shock. Secondary osteosarcoma developed in 1 patient 6 years after treatment. The overall survival was 77.8%, with a median follow-up of 40.8 months (range, 4.5-287.6 months).CONCLUSION: Children and adolescents with advanced NPC treated with combined chemotherapy and radiotherapy have a good survival rate.

Bronchopulmonary Dysplasia: New High Resolution Computed Tomography Scoring System and Correlation between the High Resolution Computed Tomography Score and Clinical Severity

OBJECTIVE: To develop an high resolution computed tomography (HRCT) scoring system for the assessment of bronchopulmonary dysplasia (BPD) and determine its usefulness as compared with the chest radiographic score. MATERIALS AND METHODS: Forty-two very low-birth-weight preterm infants with BPD (25 male, 17 female) were prospectively evaluated with HRCT performed at the mean age of 39.1-week postmenstrual age. Clinical severity of BPD was categorized as mild, moderate or severe. The HRCT score (0-36) of each patient was the sum of the number of bronchopulmonary segments with 1) hyperaeration and 2) parenchymal lesions (linear lesions, segmental atelectasis, consolidation and architectural distortion), respectively. We compared the HRCT scores with the chest radiographic scores (the Toce system) in terms of correlation with clinical severity. RESULTS: The HRCT score had good interobserver (r = 0.969, p < 0.001) and intraobserver (r = 0.986, p < 0.001) reproducibility. The HRCT score showed better correlation (r = 0.646, p < 0.001) with the clinical severity of BPD than the chest radiographic score (r = 0.410, p = 0.007). The hyperaeration score showed better correlation (r = 0.738, p < 0.001) with the clinical severity of BPD than the parenchymal score (r = 0.523, p < 0.001). CONCLUSION: We have developed a new HRCT scoring system for BPD based on the quantitative evaluation of pulmonary abnormalities of BPD consisting of the hyperaeration score and the parenchymal score. The HRCT score shows better correlation with the clinical severity of BPD than the radiographic score.

Spinal Cord Glioblastoma Induced by Radiation Therapy of Nasopharyngeal Rhabdomyosarcoma with MRI Findings: Case Report

Radiation-induced spinal cord gliomas are extremely rare. Since the first case was reported in 1980, only six additional cases have been reported.; The radiation-induced gliomas were related to the treatment of Hodgkin's lymphoma, thyroid cancer, and medullomyoblastoma, and to multiple chest fluoroscopic examinations in pulmonary tuberculosis patient. We report a case of radiation-induced spinal cord glioblastoma developed in a 17-year-old girl after a 13-year latency period following radiotherapy for nasopharyngeal rhabdomyosarcoma. MRI findings of our case are described.

The Significance of Maturation Score of Brain Magnetic Resonance Imaging in Extremely Low Birth Weight Infant

PURPOSE: The aim of this study was to investigate the effect of perinatal risk factors on brain maturation and the relationship of brain maturation and neurodevelopmental outcomes with brain maturation scoring system in brain MRI. METHODS: ELBWI infants born at the Seoul National University Children's Hospital from January 2006 to December 2010 were included. A retrospective analysis was performed with their medical record and brain MR images acquired at near full term. We read brain MRI and measured maturity with total maturation score (TMS). TMS is a previously developed anatomic scoring system to assess brain maturity. The total maturation score was used to evaluate the four parameters of maturity: (1) myelination, (2) cortical infolding, (3) involution of glial cell migration bands, and (4) presence of germinal matrix tissue. RESULTS: Images from 124 infants were evaluated. Their mean gestational age at birth was 27.1+/-2.1 weeks, and mean birth weight was 781.5+/-143.9 g. The mean TMS was 10.8+/-2.0. TMS was significantly related to the postmenstrual age (PMA) of the infant, increasing with advancing postmenstrual age (P<0.001). TMS showed no significance with neurodevelopmental delay, and with brain injury, respectively. CONCLUSION: TMS was developed for evaluating brain maturation in conventional brain MRI. The results of this study suggest that TMS was not useful for predicting neurodevelopmental delay, but further studies are needed to make standard score for each PMA and to re-evaluate the relationship between brain maturation and neurodevelopmental delay.

Unusual Thymic Hyperplasia Mimicking Lipomatous Tumor in an Eight-Year-Old Boy with Concomitant Pericardial Lipomatosis and Right Facial Hemihypertrophy

We report a case of thymic hyperplasia accompanied by pericardial lipomatosis and right facial hemihypertrophy in an 8-year-old boy. On imaging studies, the hyperplastic thymus had prominent curvilinear and nodular fatty areas simulating a fat-containing anterior mediastinal mass, which is an unusual finding in children. To our knowledge, this is the first report on a child with a combination of thymic hyperplasia, pericardial lipomatosis, and right facial hemihypertrophy. The radiologic findings are presented with a brief discussion.

Balloon Dilatation for Corrosive Esophageal Strictures in Children: Radiologic and Clinical Outcomes

OBJECTIVE: We retrospectively evaluated the effectiveness of the esophageal balloon dilatation (EBD) in children with a corrosive esophageal stricture. MATERIALS AND METHODS: The study subjects included 14 patients (M:F = 8:6, age range: 17-85 months) who underwent an EBD due to a corrosive esophageal stricture. The causative agents for the condition were glacial acetic acid (n = 9) and lye (n = 5). RESULTS: A total of 52 EBD sessions were performed in 14 patients (range 1-8 sessions). During the mean 15-month follow-up period (range 1-79 months), 12 patients (86%) underwent additional EBD due to recurrent esophageal stricture. Dysphagia improved after each EBD session and oral feeding was possible between EBD sessions. Long-term success (defined as dysphagia relief for at least 12 months after the last EBD) was achieved in two patients (14%). Temporary success of EBD (defined as dysphagia relief for at least one month after the EBD session) was achieved in 17 out of 52 sessions (33%). A submucosal tear of the esophagus was observed in two (4%) sessions of EBD. CONCLUSION: Only a limited number of children with corrosive esophageal strictures were considered cured by EBD. However, the outcome of repeated EBD was sufficient to allow the children to eat per os prior to surgical management.

Decreased heart sound in a healthy newborn: Spontaneous multiseptated cystic pneumomediastinum with delayed respiratory distress / 소아과

Spontaneous pneumomediastinum in the absence of predisposing risk factors has been rarely observed in full-term neonates. A 3-day-old neonate, delivered vaginally at term without any perinatal complications or signs of respiratory difficulty, was referred to the Seoul National University Children's Hospital because of reduced heart sound detected during routine neonatal examination. Chest computed tomography (CT) showed air collection in the anterior mediastinum. The baby developed respiratory distress on the fourth day and required supplemental oxygen. On the seventh day, there was no sign of respiratory difficulty, and x-ray examination showed no demonstrable pneumomediastinum. Hence, careful neonatal physical examination is essential during the postnatal assessment of newborns, and spontaneous pneumomediastinum should be considered when a healthy newborn presents with reduced heart sound.

Kidney Length in Normal Korean Children

PURPOSE: Renal length offers important information to detect or follow-up various renal diseases. The purpose of this study was to determine the kidney length of normal Korean children in relation to age, height, weight, body surface area (BSA), and body mass index (BMI). MATERIALS AND METHODS: Children between 1 month and 15 years of age without urological abnormality were recruited. Children below 3rd percentile and over 97th percentile for height or weight were excluded. Both renal lengths were measured in the prone position three times and then averaged by experienced radiologists. The mean length and standard deviation for each age group was obtained, and regression equation was calculated between renal length and age, weight, height, BSA, and BMI, respectively. RESULTS: Renal length was measured in 550 children. Renal length grows rapidly until 24 month, while the growth rate is reduced thereafter. The regression equation for age is: renal length (mm) = 45.953 + 1.064 x age (month, 24 months) (R2 = 0.711). The regression equation for height is: renal length (mm) = 24.494 + 0.457 x height (cm) (R2 = 0.894). The regression equation for weight is: renal length (mm) = 38.342 + 2.117 x weight (kg, 18 kg) (R2 = 0.651). The regression equation for BSA is: renal length (mm) = 31.622 + 61.363 xBSA (m2, 0.7) (R2 = 0.715). The regression equation for BMI is: renal length (mm) = 44.474 + 1.163 x BMI (R2 = 0.079). CONCLUSION: This study provides data on the normal renal length and its association with age, weight, height, BSA and BMI. The results of this study will guide the detection and follow-up of renal diseases in Korean children.