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Objectives: To investigate consistency in shear wave velocities (SWVs) on ultrasound elastography using different machines, transducers and acquisition depths., Methods: The SWVs were measured using an elasticity phantom with a Young's modulus of 16.9 kPa, with three recently introduced ultrasound elastography machines (A, B and C from different vendors) and two transducers (low and high frequencies) at four depths (2, 3, 4 and 5 cm). Mean SWVs from 15 measurements and coefficient of variations (CVs) were compared between three machines, two transducers and four acquisition depths., Results: The SWVs using the high frequency transducer were not acquired at 5 cm depth in machine B, and a high frequency transducer was not available in machine C. The mean SWVs in the three machines were different (p ≤ 0.002). The CVs were 0-0.09 in three machines. The mean SWVs between the two transducers were different (p < 0.001) except at 4 and 5 cm depths in machine A. The SWVs were affected by the acquisition depths in all conditions (p < 0.001)., Conclusion: There is considerable difference in SWVs on ultrasound elastography depending on different machines, transducers and acquisition depths. Caution is needed when using the cutoff values of SWVs in different conditions., Key Points: • The shear wave velocities (SWVs) are different between different ultrasound elastography machines • The SWVs are also different between different transducers and acquisition depths • Caution is needed when using the cutoff SWVs measured under different conditions.

Purpose: We aimed to evaluate the use of a dose monitoring program for calculating and comparing the diagnostic radiation doses in pediatric patients with neuroblastoma., Methods: We retrospectively reviewed diagnostic and therapeutic imaging studies performed on pediatric patients with neuroblastoma from 2003 to 2014. We calculated the mean effective dose per exam for X-ray, conventional computed tomography (CT), and CT of positron emission tomography/computed tomography (PET/CT) from the data collected using a dose monitoring program (DoseTrack group) since October 2012. Using the data, we estimated the cumulative dose per person and the relative dose from each modality in all patients (Total group). The effective dose from PET was manually calculated for all patients., Results: We included 63 patients with a mean age of 3.2±3.5 years; 28 had a history of radiation therapy, with a mean irradiated dose of 31.9±23.2 Gy. The mean effective dose per exam was 0.04±0.19 mSv for X-ray, 1.09±1.11 mSv for CT, and 8.35±7.45 mSv for CT of PET/CT in 31 patients of the DoseTrack group. The mean estimated cumulative dose per patient in the Total group was 3.43±2.86 mSv from X-ray (8.5%), 7.66±6.09 mSv from CT (19.1%), 18.35±13.52 mSv from CT of PET/CT (45.7%), and 10.71±10.05 mSv from PET (26.7%)., Conclusion: CT of PET/CT contributed nearly half of the total cumulative dose in pediatric patients with neuroblastoma. The radiation dose from X-ray was not negligible because of the large number of X-ray images. A dose monitoring program can be useful for calculating radiation doses in patients with cancer.

Purpose: To investigate the proper diagnostic modalities and failure cases of treatment in patients with single-system ectopic ureter (SSEU) who underwent nephrectomy for incontinence., Methods: SSEU combined with dysplastic kidney is a rare cause of female incontinence. We retrospectively analyzed 45 pediatric SSEU patients that underwent simple nephrectomy at our institution during 1996-2013 for incontinence. We reviewed imaging studies to detect dysplastic kidney and ectopic ureter insertion, postoperative results, and urodynamic findings for remaining incontinence after nephrectomy., Results: Median operative age was 59.3months. Both ultrasonography and magnetic resonance imaging (MRI) showed 50.0% dysplastic kidney detection rates respectively. Dimercaptosuccinic acid (DMSA) scanning and computerized tomography (CT) showed equal detection rates of 95.5%. Ectopic ureter insertion sites were determined by ultrasonography, CT, and MRI in 17.5%, 13.6%, and 33.3% of patients, respectively. Renal vascular structures were identified in 3/22 patients (13.6%) with CT. Post-nephrectomy, incontinence disappeared in 41 patients (91.1%), but remained in 4 patients (8.9%); urodynamics suggested bladder neck incompetence in these patients., Conclusions: DMSA is a highly sensitive diagnostic modality for detecting dysplastic kidney in SSEU patients with more than 95% detection rates. Once detected by DMSA, additional CT or MRI studies do not provide further information about ectopic ureter insertion or renal vascular structure. Although nephrectomy is successful in nearly 90% of SSEU patients with dysplastic kidneys, postoperative incontinence occasionally remains and requires additional treatment., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objectives: To compare the detectability of perfusion difference between normal and undescended testes (UDT) in young children using conventional Power Doppler Imaging (PDI) and Superb Microvascular Imaging (SMI)., Methods: We prospectively performed testicular ultrasonography including PDI and SMI for the evaluation of microvascular flow in young children. Microvascular flow was categorized into four grades (grade 0-4). Statistical analysis was performed to compare the differences between undescended and normal testes., Results: We imaged 40 testes from 20 boys (age, 2-29 months). Testes sizes and volumes were similar between the 29 normal and 11 UDT. PDI demonstrated low grade flow in most normal (19/29) and UDT (11/11) without difference (P=0.130). However, SMI detected differences in flow grades between normal and UDT (P<0.001). In univariate analysis, age (odds ratio [OR], 0.829; P=0.012) and low grade flow on SMI (OR of grade 0, 51.886 with P<0.001 and OR of grade 1, 14.29 with P=0.017) were associated with UDT. These parameters were also significant in multivariate analysis with larger area under the curve, compared with the results using PDI (0.892 vs. 0.726, P=0.002)., Conclusions: SMI can detect perfusion difference between normal and UDT in young children better than PDI., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Humidifier disinfectant-associated children's interstitial lung disease has an unpredictable clinical course with a high morbidity and mortality., Objectives: To evaluate the differences in clinical findings between survivors and non-survivors of humidifier disinfectant-associated children's interstitial lung disease. To evaluate dynamic changes in serum cytokines related to inflammation and fibrosis in lung injury, and to determine whether these changes are predictive of survival in this disease., Methods: We evaluated 17 children with humidifier disinfectant-associated children's interstitial lung disease, from whom serum samples were obtained weekly during hospitalization. The severity of chest tomographic and lung pathologic findings was scored. Levels of several cytokines were measured in the serial serum samples., Results: Seven of the 17 children were survivors. Compared to survivors, non-survivors had greater ground-glass attenuation on follow-up chest tomography, higher admission neutrophil counts, and more macrophages on pathologic findings. Transforming growth factor-beta 1 persisted at an elevated level (1,000-1,500 pg/ml) in survivors, whereas it decreased abruptly in non-survivors. At the time of this decrease, non-survivors had clinical worsening of their respiratory failure. Transforming growth factor-beta 1 was positively correlated with PaO2 /FiO2 (r = 0.481, P < 0.0001)., Conclusions: Non-survivors exhibited more inflammatory clinical findings than survivors. Transforming growth factor-beta 1 remained elevated in survivors, suggesting that it affected the clinical course of humidifier disinfectant-associated children's interstitial lung disease. The prognosis of this lung disease may depend more on controlling excessive inflammation and repairing damaged lung than on fibrosis, and transforming growth factor-beta 1 may play a key role in this process., (© 2015 Wiley Periodicals, Inc.)

Aim: To evaluate the possibility of treatment effect monitoring using hepatic fat quantification magnetic resonance (MR) in pediatric nonalcoholic steatohepatitis (NASH)., Methods: We retrospectively reviewed the medical records of patients who received educational recommendations and vitamin E for NASH and underwent hepatic fat quantification MR from 2011 to 2013. Hepatic fat fraction (%) was measured using dual- and triple-echo gradient-recalled-echo sequences at 3T. The compliant and non-compliant groups were compared clinically, biochemically, and radiologically., Results: Twenty seven patients (M:F = 24:3; mean age: 12 ± 2.3 years) were included (compliant group = 22, non-compliant = 5). None of the baseline findings differed between the 2 groups, except for triglyceride level (compliant vs non-compliant, 167.7 mg/dL vs 74.2 mg/dL, P = 0.001). In the compliant group, high-density lipoprotein increased and all other parameters decreased after 1-year follow-up. However, there were various changes in the non-compliant group. Dual-echo fat fraction (-19.2% vs 4.6, P < 0.001), triple-echo fat fraction (-13.4% vs 3.5, P < 0.001), alanine aminotransferase (-110.7 IU/L vs -10.6 IU/L, P = 0.047), total cholesterol (-18.1 mg/dL vs 3.8 mg/dL, P = 0.016), and triglyceride levels (-61.3 mg/dL vs 11.2 mg/dL, P = 0.013) were significantly decreased only in the compliant group. The change in body mass index and dual-echo fat fraction showed a positive correlation (ρ = 0.418, P = 0.030)., Conclusion: Hepatic fat quantification MR can be a non-invasive, quantitative and useful tool for monitoring treatment effects in pediatric NASH.

Aim: To investigate perfusion change in contrast-enhanced ultrasonography (CEUS) to evaluate liver fibrosis based on biliary obstruction using an animal model., Methods: New Zealand white rabbits (3-4 kg) underwent bile duct ligation to form a biliary obstruction model. We performed liver CEUS and laboratory tests on the day before the operation (day 0) and every 7 postoperative days until the rabbits were sacrificed. After CEUS, signal intensity of liver parenchyma with a time-intensity curve was analyzed. Perfusion parameters were automatically calculated from region-of-interests, including peak signal intensity, mean transit time, area under the curve and time to peak. Histological grades of liver fibrosis were assessed according to the Metavir score system immediately after sacrifice. Generalized estimating equations were used to analyze the association between liver fibrosis grades and perfusion parameters for statistical analysis. The perfusion parameters were measured on the last day and the difference between day 0 and the last day were evaluated., Results: From the nine rabbits, histological grades of liver fibrosis were grade 1 in one rabbit, grade 2 and 3 in three rabbits each, and grade 4 in two rabbits. Among the four CEUS parameters, only the peak signal intensity measured on the last day demonstrated a significant association with liver fibrosis grades (OR = 1.392, 95%CI: 1.114-1.741, P = 0.004). The difference in peak signal intensity between day 0 and the last day also demonstrated an association with liver fibrosis (OR = 1.191, 95%CI: 0.999-1.419, P = 0.051). The other parameters tested, including mean transit time, area under the curve, and time to peak, showed no significant correlation with liver fibrosis grades., Conclusion: This animal study demonstrates that CEUS can be used to evaluate liver fibrosis from biliary obstruction using peak signal intensity as a parameter.

Background: New CT reconstruction techniques may help reduce the burden of ionizing radiation., Objective: To quantify radiation dose reduction when performing pediatric chest CT using a low-dose protocol and 50% adaptive statistical iterative reconstruction (ASIR) compared with age/gender-matched chest CT using a conventional dose protocol and reconstructed with filtered back projection (control group) and to determine its effect on image quality in normal weight and overweight children., Materials and Methods: We retrospectively reviewed 40 pediatric chest CT (M:F = 21:19; range: 0.1-17 years) in both groups. Radiation dose was compared between the two groups using paired Student's t-test. Image quality including noise, sharpness, artifacts and diagnostic acceptability was subjectively assessed by three pediatric radiologists using a four-point scale (superior, average, suboptimal, unacceptable)., Results: Eight children in the ASIR group and seven in the control group were overweight. All radiation dose parameters were significantly lower in the ASIR group (P < 0.01) with a greater than 57% dose reduction in overweight children. Image noise was higher in the ASIR group in both normal weight and overweight children. Only one scan in the ASIR group (1/40, 2.5%) was rated as diagnostically suboptimal and there was no unacceptable study., Conclusion: In both normal weight and overweight children, the ASIR technique is associated with a greater than 57% mean dose reduction, without significantly impacting diagnostic image quality in pediatric chest CT examinations. However, CT scans in overweight children may have a greater noise level, even when using the ASIR technique.

Purpose: To investigate the meaning of ureter dilatation during ultrasonography (US) in infants for evaluating vesicoureteral reflux (VUR)., Materials and Methods: We retrospectively reviewed abdominal US images of infants who were diagnosed with urinary tract infection (UTI group) or only hydronephrosis without UTI (control group). Hydronephrosis (graded 0-4) and ureter dilatation (present or absent) were evaluated on each side with US. Voiding cystourethrography (VCUG) within 3 months time interval with US was also reviewed and VUR was graded (0-5) on each side. Hydronephrosis, ureter dilatation, and VUR were then compared between the two groups., Results: Four hundred and three infants (142 in the UTI group and 261 in the control group) were included and VCUG was performed in 129 infants (68 in UTI and 61 in control groups). VUR grades were not different between the two groups (p=0.252). Hydronephrosis grade was not related to VUR in either group (p>0.05). However, ureter dilatation had a significant relationship with VUR in the UTI group (p=0.015), even among patients with a high-grade VUR (p=0.005). Whereas, ureter dilatation was not associated with VUR in the control group (p=0.744). The relationship between ureter dilatation and VUR was different between the two groups for both all grades (p=0.014) and high-grade (p=0.004) VUR. Ureter dilatation had 66.7% sensitivity, 80.3% specificity, and 79.4% accuracy for evaluating high-grade VUR in the UTI group., Conclusion: Ureter dilatation on US can be a helpful finding for detecting VUR in infants with UTI, but not infants without UTI., (Copyright © 2014. Published by Elsevier Ireland Ltd.)

Background: Iterative reconstruction can be helpful to reduce radiation dose while maintaining image quality. However, this technique has not been fully evaluated in children during abdominal CT., Objective: To compare objective and subjective image quality between half-dose images reconstructed with iterative reconstruction at iteration strength levels 1 to 5 (half-S1 to half-S5 studies) and full-dose images reconstructed with filtered back projection (full studies) in pediatric abdominal CT., Materials and Methods: Twenty-one children (M:F = 13:8; mean age 8.2 ± 5.7 years) underwent dual-source abdominal CT (mean effective dose 4.8 ± 2.1 mSv). The objective image quality was evaluated as noise. Subjective image quality analysis was performed comparing each half study to the full study for noise, sharpness, artifact and diagnostic acceptability., Results: Both objective and subjective image noise decreased with increasing iteration strength. Half-S4 and -S5 studies showed objective image noise similar to or lower than that of full studies. The half-S2 and -S3 studies produced the greatest sharpness and the half-S5 studies were the worst from a blocky appearance. Full and half studies did not differ in artifacts. Half-S3 studies showed the best diagnostic acceptability., Conclusion: Half-S4 and -S5 studies objectively and half-S3 studies subjectively showed comparable image quality to full studies in pediatric abdominal CT.

Background: Since children are more radio-sensitive than adults, there is a need to minimize radiation exposure during CT exams., Objective: To evaluate the effects of adaptive statistical iterative reconstruction (ASIR) on radiation dose reduction, image quality and diagnostic accuracy in pediatric abdominal CT., Materials and Methods: We retrospectively reviewed the abdominal CT examinations of 41 children (24 boys and 17 girls; mean age: 10 years) with a low-dose radiation protocol and reconstructed with ASIR (the ASIR group). We also reviewed routine-dose abdominal CT examinations of 41 age- and sex-matched controls reconstructed with filtered-back projection (control group). Image quality was assessed objectively as noise measured in the liver, spleen and aorta, as well as subjectively by three pediatric radiologists for diagnostic acceptability using a four-point scale. Radiation dose and objective image qualities of each group were compared with the paired t-test. Diagnostic accuracy was evaluated by reviewing follow-up imaging studies and medical records in 2012 and 2013., Results: There was 46.3% dose reduction of size-specific dose estimates in ASIR group (from 13.4 to 7.2 mGy) compared with the control group. Objective noise was higher in the liver, spleen and aorta of the ASIR group (P < 0.001). However, the subjective image quality was average or superior in 84-100% of studies. Only one image was subjectively rated as unacceptable by one reviewer. There was only one case with interpretational error in the control group and none in the ASIR group., Conclusion: Use of the ASIR technique resulted in greater than a 45% reduction in radiation dose without impairing subjective image quality or diagnostic accuracy in pediatric abdominal CT, despite increased objective image noise.

Objective: The objective of this study was to compare the radiation dose and image quality of pediatric abdominal computed tomography (CT) using a protocol reconstructed with filtered back projection (FBP) and a protocol with both kVp and mAs modulation and sinogram-affirmed iterative reconstruction (SAFIRE)., Materials and Methods: We retrospectively reviewed pediatric abdominal CT examinations performed with both kVp and mAs modulation. These raw data were reconstructed with SAFIRE at different strengths from 2 to 4 (SAFIRE groups 2-4). Another set of age/sex-matched pediatric abdominal CT examinations were also reviewed, which were performed during the same period with only mAs modulation and FBP (control group). The radiation dose and image quality were compared between groups. The image quality was objectively evaluated as the noise measured in the liver, aorta, and spleen at the level of the main portal vein and the image quality was subjectively reviewed by two radiologists for diagnostic acceptability using a four-point scale (0: unacceptable; 1: worse than the control group, but acceptable; 2: comparable with the control group; and 3: better than the control group). An independent t test was used in order to compare the radiation dose. An independent t test with Bonferroni correction and generalized estimating equations were used for the comparison of the objective and subjective image quality, respectively., Results: Twenty-nine patients (M:F=19:10; mean age, 10.0 years) were enrolled in each group. The SAFIRE group, using the size-specific dose estimates calculation method showed a 64.2% radiation dose reduction (from 8.1 to 2.9 mGy, P<.05), compared with the results of the control group. The objective image noise of the SAFIRE groups 2 and 3 was comparable to that of the control group. The subjective image quality was the best in SAFIRE group 3 [odds ratio (OR) 3.015, P<.001 when comparing to SAFIRE group 0; OR 1.513, P<.001 when comparing to SAFIRE group 2]., Conclusions: Image acquisition with both kVp and mAs modulation and iterative reconstruction using SAFIRE with strength 3 can preserve the objective and subjective image quality of pediatric abdominal CT scans with less than half the radiation dose., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Variable sequences can be used in MR enterography, and no consensus exists for the best protocol in children with Crohn disease., Objective: To compare the lesion detectability of various MR enterography sequences and to correlate the findings of these sequences with the Pediatric Crohn's Disease Activity Index (PCDAI) in children with Crohn disease., Materials and Methods: Children with clinically or pathologically confirmed Crohn disease underwent MR enterography, including a single-shot fast spin-echo (SSFSE) sequence, motility imaging (coronal 2-D balanced fast field echo), diffusion-weighted imaging (DWI), and dynamic contrast enhancement imaging (including arterial, portal and delayed phases). The lesion detectability of each sequence was graded 0-2 for each involved bowel segment. The lesion detectability and PCDAI result on different sequences were compared using the weighted least squares method and Student's t-test, respectively., Results: Fifteen children (11 boys, 4 girls, mean age 13.7 ± 1.4 years) with a total of 41 lesions were included in this study. All lesions detected in more than two sequences were visible on the single-shot fast spin-echo (SSFSE) sequence. The relative lesion detection rate was 78.1% on motility imaging, 90.2% on DWI, and 92.7% on arterial, 95.1% on portal and 95.1% on delayed phase imaging. Compared to the SSFSE sequence, motility imaging (P < 0.001) and DWI (P = 0.039) demonstrated lower detectability. The mean PCDAI result in the detected lesions was statistically higher only on dynamic enhancement imaging (P < 0.001)., Conclusion: All MR enterography sequences were found to have relatively high lesion detectability in children with Crohn disease, while motility imaging showed the lowest lesion detectability. Lesions detected on dynamic enhancement imaging showed a higher PCDAI result, which suggests that this sequence is specific for active inflammation.

Purpose: To measure shear wave velocities (SWVs) by acoustic radiation force impulse (ARFI) ultrasound elastography in normal kidneys and in hydronephrotic kidneys in young children and to compare SWVs between the hydronephrosis grades., Methods: This study was approved by an institutional review board, and informed consent was obtained from the parents of all the children included. Children under the age of 24 months were prospectively enrolled. Hydronephrosis grade was evaluated on ultrasonography, and three valid ARFI measurements were attempted using a high-frequency transducer for both kidneys. Hydronephrosis was graded from 0 to 4, and high-grade hydronephrosis was defined as grades 3 and 4., Results: Fifty-one children underwent ARFI measurements, and three valid measurements for both kidneys were obtained in 96% (49/51) of the patients. Nineteen children (38.8%) had no hydronephrosis. Twenty-three children (46.9%) had unilateral hydronephrosis, and seven children (14.3%) had bilateral hydronephrosis. Seven children had ureteropelvic junction obstruction (UPJO). Median SWVs in kidneys with high-grade hydronephrosis (2.02 m/sec) were higher than those in normal kidneys (1.75 m/sec; P=0.027). However, the presence of UPJO did not influence the median SWVs in hydronephrotic kidneys (P=0.362)., Conclusion: Obtaining ARFI measurements of the kidney is feasible in young children with median SWVs of 1.75 m/sec in normal kidneys. Median SWVs increased in high-grade hydronephrotic kidneys but were not different between hydronephrotic kidneys with and without UPJO.

Background: Biliary atresia (BA) is a progressive, obliterative cholangiopathy that occurs in neonates with hepatic portoenterostomy the treatment of choice, but early surgery is important for optimum outcomes. MRI, including MR cholangiopancreatography (MRCP) may be a diagnostically useful alternative to US, but the heavily T2-weighted sequences used include not only bile duct signals, but also other heterogeneously high signal intensities from surrounding structures., Objective: To evaluate the effects of gadolinium when used to decrease background signal intensity on T2-weighted MR cholangiopancreatography (MRCP) in infants and to evaluate the qualitative improvement of the depiction of the common bile duct (CBD) for evaluating neonatal cholestasis., Materials and Methods: Our Institutional Review Board approved this prospective study. MRCP was performed with gadopentetate dimeglumine injection using a 1.5-T scanner. Pre- and postcontrast MRCP images were compared. Forty-nine infants (male:female = 21:28; age 0-12 months, mean 2.3) were included. The final diagnoses were biliary atresia (BA) in 28 cases and non-BA in 21. Quantitative analysis was conducted using region-of-interest measurements of mean signal intensities of the liver, pancreatic head and gallbladder (if defined). Qualitative analysis was performed by four radiologists who subjectively scored image confidence in the presence of CBD on a 4-point scale (0 for definitely absent, 1 for probably absent, 2 for probably present, and 3 for definitely present)., Results: The signal-to-noise ratios were significantly decreased in the liver and pancreatic head after contrast medium enhancement (mean 5.7→4.0 in liver and mean 44.9→12.7 in the pancreatic head; P < 0.0001), and this finding was constant in both the BA and the non-BA group. The mean confidence score in the presence of CBD decreased in the BA group (0.9→0.5; P < 0.0001), but did not change significantly in the non-BA group (2.0→2.1; P = 0.459) after contrast medium enhancement. Both intra- and interobserver agreement was higher after contrast medium enhancement (P = 0.046)., Conclusion: Gadopentetate dimeglumine-enhanced MRCP increased the diagnostic confidence of absence of the CBD in cholestatic infants with increased intra- and interobserver agreement.

Background: The degree of hepatic fibrosis in biliary atresia (BA) correlates with the prognosis of the disease and thus, early diagnosis of liver fibrosis is clinically important. Liver biopsy is the gold standard for the evaluation of liver fibrosis, but it is an invasive procedure requiring sedation in children. Therefore, it is desirable to identify a noninvasive method for diagnosis and follow-up of hepatic fibrosis., Objective: The purpose of this study is to evaluate the possibility of quantifying liver fibrosis in infants by T2 relaxation time measurements., Materials and Methods: The institutional review board approved this prospective study and parental informed consent was obtained. During MR cholangiopancreatography using a 1.5-T MR scanner in infants with neonatal cholestasis, T2 relaxation time of the liver was calculated with the mean signal intensities measured on images obtained using spin-echo sequences (TR/TE, 2,000/20, 40, 60, 80, 100, 120, 140, 160 ms). A normal control study was performed during spinal MRI in infants with anorectal malformation and normal liver enzyme profiles. A liver biopsy was obtained in the children with cholestasis. The correlation between histopathological fibrosis stage and T2 relaxation time was evaluated by Kendall's Tau-b test., Results: Twenty-five infants (male: female, 12:13; age range 0-11 months, mean 3.2 months), 14 with neonatal cholestasis (9 BA and 5 non-BA) and 11 normal controls were included in this study. Relaxation times (mean ± standard deviation [SD]) for the liver were 57.8 ms ± 8.8 in the normal control group (n=11) and 56.8 ms ± 9.6 in the BA group (n=9) without statistically significant differences (P=0.811). T2 relaxation times were not significantly different between the low stage (≤ F1) and high stage (≥ F2) fibrosis (mean 57.8 vs 56.8; P=0.934)., Conclusion: T2 relaxation of a normal infant liver at 1.5-T had a mean value of 57.8 ms, which is comparable with adult data (46-57 ms). However, T2 relaxation time was not different in patients with BA and did not correlate with stage of fibrosis.

Background: Spontaneous bile duct perforation (SBP) is rare in children. Early diagnosis is important because the condition can be treated surgically., Objective: The purpose of this study is to report MR cholangiopancreatography (MRCP) findings of SBP and to evaluate the usefulness of MRCP., Materials and Methods: Over the last 10 years, three children (1 boy, 2 girls; ages 3, 4 and 15 months) underwent US, MRCP and hepatobiliary scintigraphy preoperatively and were surgically confirmed to have extrahepatic bile duct perforation., Results: US showed ascites in all children and a choledochal cyst in one. On MRCP, a moderate-to-large volume of ascites was seen in addition to a loculated fluid collection at the porta hepatis. MRCP also depicted the low insertion of the cystic duct and choledochal cyst in each case. Hepatobiliary scintigraphy showed bile leak from the region of the porta hepatis extending to the whole abdomen. According to the surgical findings, the perforation site was around the junction of the cystic duct and the common hepatic duct in all children., Conclusion: In children with SBP, MRCP can depict the loculated fluid collection adjacent to the perforation site and associated bile duct anomalies.

Aim: The use of a central venous catheter (CVC) through the internal jugular vein (IJV) in neonates is associated with various complications. We postulated that the risk of vein deformity after removing the CVC is underestimated. This study aimed to evaluate, using Doppler ultrasound, morphological changes in the IJV that had undergone CVC insertion during the neonatal period., Methods: The study consisted of 23 cases, in which 2.7 Fr Broviac (Bard Access Systems, Salt Lake City, Utah, USA) CVCs were inserted through the IJVs of newborns over a 2-year period. After the removal of the CVCs, the IJVs were examined by Doppler ultrasound., Results: Seventeen cases had normal appearances, but six (26%) cases had deformities. One case had a completely obstructed IJV, and five had abnormal compressibility, echogenic intravascular masses or monophasic waveforms of blood flow. On follow-up, IJV deformities were not improved but tended to be aggravated. There were significant differences in gestational age (36.6 +/- 3.2 weeks vs. 30.0 +/- 3.9 weeks, P= 0.002), body weight at time of CVC insertion (2.60 +/- 0.72 kg vs. 1.32 +/- 0.47 kg, P= 0.001) and duration of catheter use (25.9 +/- 13.6 days vs. 49.0 +/- 22.0 days, P= 0.016) between the normal and deformity groups, respectively., Conclusions: IJV deformities after central venous catheterisation in neonates are common. A lower gestational age, a lower body weight, and more catheter indwelling days are significant factors affecting the incidence of IJV deformities.

Background and Aim: To assess fecal retention, plain abdominal radiography is frequently used to complement the clinical history and physical examination, and three scoring systems have been proposed by Barr, Blethyn, and Leech on a single abdominal radiography. The aim of the present study was to find simple and useful diagnostic tools for an approach to fecal retention by correlation of the three scoring systems with the clinical characteristics., Methods: This study included 76 children (5.6-15.4 years, male : female = 33:43) who presented with various gastrointestinal complaints and 20 healthy children from the years 2004-2008. Defecation characteristics, abdominal pain, anorexia and nausea, the Bristol stool form scale, and colonic transit time were studied. Plain abdominal radiographs were independently scored with the three scoring systems by a pediatrician and a radiologist., Results: The k-value of the Leech score (0.912) between two of the observers was higher than the others (Barr 0.870 and Blethyn 0.670), and the correlation coefficients of the Leech scoring system by a pediatrician in relation to the colonic transit time (r = 0.861, P < 0.001) and the Bristol stool form scale (r = -0.818, P < 0.001) were highest in the constipated children. Furthermore, there were statistically significant associations between the Leech scoring system and the defecation frequency per week (r = -0.569 and -0.625 in two observers) or abdominal pain (r = 0.574 and 0.567)., Conclusions: The Leech score and the Bristol stool form scale may be simple and useful diagnostic tools for pediatricians to access childhood fecal loading in outpatient clinics along with a thorough clinical history.

We evaluated the efficacy of dimercaptosuccinic acid (DMSA) scan and ultrasound (US) in comparison with voiding cystourethrography (VCUG) in predicting vesicoureteral reflux (VUR) in children below the age of 2 years. Medical records and radiologic studies of children (<2 years) suffering their first febrile urinary tract infection (UTI) between January 2001 and May 2007 were retrospectively reviewed. We evaluated the sensitivity, specificity, and positive and negative predictive values of US and DMSA scans in diagnosing VUR. Among 220 children with their first febrile UTI, VUR was detected in 67 (30.4%). The detection rate of VUR by US was 41.7% and 86% in the low (I, II) and high grade (III~IV) groups, respectively. Detection rate of VUR by DMSA scan was 37.5% and 88.4% in the low and high grade groups, respectively. Combining US and DMSA scan, we found that the detection rate of high grade VUR was 95.3% and that of low grade was 62.5%. During follow up, most of the low grade VURs with normal DMSA and US scans resolved or were downgraded. Most high grade VURs could be detected by US and DMSA scan, but the prediction rate was not as high in low grade VURs. However, we can anticipate spontaneous improvement without complications in patients with either low or high grade reflux and negative findings on US and DMSA scan.

Gastrointestinal tract duplications are uncommon congenital abnormalities arising anywhere along the alimentary tract. The most common modalities used to image duplications are US and contrast medium examinations. CT and MRI are less often used, but can be helpful in difficult cases that require a multiplanar approach. In this article, we discuss and illustrate a wide spectrum of gastrointestinal tract duplications from the oesophagus to the rectum, and illustrate the associated abnormalities of gastrointestinal tract duplications.

Antiphospholipid syndrome (APS) has been recognized as the leading cause of vascular thrombosis in children. The syndrome may occur in isolation or in association with an underlying systemic disease, particularly systemic lupus erythematosus. Less than 1% of patients with APS present with a life-threatening condition resulting from thrombosis in multiple organs and subsequent multiorgan failure, which is defined as catastrophic APS. Early recognition of APS is essential because prompt and appropriate management can result in favorable outcome. We present the case of a 7-year-old girl with APS who presented with cerebral, femoral, and renal involvement in the second week of the disease progress. The patient presented with multiple thrombotic episodes and rapidly progressive renal failure. Renal cortical infarction was diagnosed by magnetic resonance imaging.

To assess the detection rate of nutcracker syndrome in children with isolated hematuria, renal Doppler ultrasound examinations were routinely performed on 216 consecutive children (176 microscopic hematuria and 40 gross hematuria). Renal Doppler ultrasound was also performed on 32 healthy normal children. The peak velocity (PV) was measured at the hilar portion of the left renal vein (LRV) and at the LRV between the aorta and the superior mesenteric artery. The PV at the aortomesenteric portion (P=0.003) and the PV ratios of the LRV (P=0.003) were significantly higher in children with hematuria than in normal children, while the PV at the hilar portion was not different. If a PV ratio of the LRV of at least 4.1 (the cut-off level set at the mean +/-2 SD of the value for the normal children) was defined as abnormal, 72 cases (33.3%) in children with hematuria and no cases in normal children were diagnosed as having nutcracker syndrome. The prevalence of nutcracker syndrome is relatively high in children with isolated hematuria, and the inclusion of renal Doppler ultrasound as a screening examination has a substantial effect on the detection of nutcracker syndrome.

To elucidate the Doppler ultrasonographic cut-off value of nutcracker syndrome causing hematuria in children, we analyzed Doppler spectral findings between 15 children with nutcracker syndrome and 15 age- and sex-matched normal control subjects. A follow-up Doppler ultrasound (US) was also performed in children with nutcracker syndrome when hematuria subsided completely after a median period of 1.7 years (range: 1.0-3.5 years) (relieved nutcracker syndrome). The peak velocity (PV) ratios of the left renal vein (LRV) were significantly higher in children with nutcracker syndrome than in those with relieved nutcracker syndrome (P<0.0001) and normal children (P<0.0001). The PV ratios of the LRV at the follow-up US were significantly higher than those in the control subjects (P=0.019). None of the 15 normal children showed PV ratios of the LRV>3.7, but five of the 15 children with relieved nutcracker syndrome without hematuria had PV ratios of 3.91-5.02. When we set the cut-off values for nutcracker syndrome at the mean+/-2 SD (mean: 2.95+/-0.92, range: 1.60-5.02) of 30 controls (normal children and relieved nutcracker without hematuria), the calculated cut-off value was 4.8, and the sensitivity and specificity were 100% and 93%, respectively. Given its high sensitivity, renal Doppler US can be used as a useful initial non-invasive test in the diagnosis of nutcracker syndrome in children with hematuria.

Anomalous union between the pancreatic and biliary systems (APBDU) has been reported to produce choledochal cyst. The aim of this experiment was to evaluate the role of sphincteroplasty to adverse effect of APBDU in an animal model. Twelve mongrel puppies were randomly divided into a control group (n = 5) and an experimental group (n = 7). A well-established model of APBDU was produced in both groups. Transduodenal sphincteroplasty was performed only on the experimental group. For all animals, serial chemical analyses of serum were performed, and biliary tree sizes were measured by magnetic resonance cholangiography 2.5 months after the experimental surgery. At the time of animal sacrifice, 3 months after the experimental surgery, operative cholangiography was performed, and bile juice and tissues were obtained for chemical analysis and histologic examination. Dilatation of the bile duct and thickening of the wall of the bile duct were observed less frequently in the experimental group than in the control group. There were no significant differences found in pancreatic enzyme activity in the bile juice between the two groups. Denudation of the mucosa was the predominant mucosal change seen in the experimental group, while epithelial hyperplasia was the predominant mucosal change found in the control group. Our experiment shows that sphincteroplasty is not effective to prevent the pancreaticobiliary reflux, but may be effective to reduce the degree of both bile duct dilatation and mural thickening in the APBDU puppy model.

We report a 5-year-old girl with idiopathic hypercalciuria who developed gross hematuria and left flank pain despite normalization of calciuria, a renal stone, and microscopic hematuria. She was found to have nutcracker syndrome by renal Doppler ultrasound, which revealed the significant differences of the peak blood flow velocities in the two portions of the left renal vein.

Objective: To determine the effects of a postoperative early isolated lumbar extension muscle-strengthening program on pain, disability, return to work, and power of back muscle after operation for herniated lumbar disc., Methods: Seventy-five patients were randomized into an exercise group (20 men, 15 women) and a control group (18 men, 22 women) to perform a prospective controlled trial of a lumbar extension exercise program in patients who underwent lumbar microdiscectomy or percutaneous endoscopic discectomy. Six weeks after surgery, patients in the exercise group undertook a 12-week lumbar extension exercise program. The assessment included measures of lumbar extensor power by the MedX (Ocala, FL) lumbar extension machine, muscle mass of multifidus and longissimus (L4-L5 cross-sectional area) by computed tomography. All patients completed the visual analog scale and the Oswestry disability index to assess pain and disability, respectively. Return to work data were also investigated., Results: After the exercise program, significant improvements were observed in the exercise group versus the control group for lumbar extensor power (51.67% versus 17.55%, respectively; P < 0.05), the cross-sectional area of multifidus and longissimus muscle (29.23% versus 7.2%, respectively; P < 0.05), and the visual analog scale score (2.51 versus 4.30, respectively; P < 0.05). The percentages of returning to work within 4 months after surgery were significantly greater in the exercise group than in the control group (87% versus 24%, respectively). Although this was not statistically significant (P > 0.05), the Oswestry disability index scores in the exercise group were better than that in control group (24.6 versus 30.6, respectively)., Conclusion: These results support the positive effects of the postoperative early lumbar extension muscle-strengthening program on pain, return to work, and strength of back muscles in patients after operation of herniated lumbar disc.

To identify factors affecting spontaneous resolution of hematuria in children with nutcracker syndrome, 20 patients diagnosed as having nutcracker syndrome using renal Doppler ultrasound (US) were analyzed retrospectively. Sixteen patients had microscopic hematuria, and four had gross hematuria at presentation. The mean age was 10.6 years (range 2.5-14 years). All underwent a follow-up Doppler US examination after a mean period of 1.4 years (range 0.5-3.5 years) after the first US was performed, and height and weight were measured at the time of US. At the time of follow-up US, hematuria disappeared in 15 patients and improved in 3. The peak velocity (PV) ratios of the left renal vein (LRV) at the follow-up US decreased significantly when compared to the first US examination (7.74+/-2.64 vs 3.50+/-1.09, p<0.0001), and height (147.4+/-20.1 vs 152.3+/-18.8 cm) and weight (36.1+/-10.9 vs 42.3+/-12.7 kg) increased (p<0.0001). Changes in the PV ratios of the LRV correlated positively with changes in the PV at the aortomesenteric portion (r=0.569, p=0.009). Changes in the PV at the aortomesenteric portion correlated negatively with changes in body mass index (BMI) (r=-0.543, p=0.013). Although spontaneous resolution of hematuria in children with nutcracker syndrome is obscure, our findings suggest the increase in BMI may be a possible hemodynamic factor.

Purpose: The aim of this study was to introduce a new surgical technique for the correction of congenital cricotracheal stenosis., Methods: A 5-day-old girl presented with esophageal atresia and congenital cricotracheal stenosis. After successfully correcting her esophageal atresia, the authors chose to use a type of slide cricotracheoplasty, which was a modification of slide tracheoplasty and anterior cricoid split., Results: The postoperative period was remarkably uneventful except for minor subcutaneous emphysema, and the midterm results were excellent., Conclusions: Slide cricotracheoplasty produced a good result and offered the same advantages as slide tracheoplasty. The authors believe that the described technique offers an efficient surgical procedure for the single-staged correction of congenital cricotracheal stenosis., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

Objective: The purpose of this study was to determine whether MR cholangiopancreatography can accurately depict anomalous pancreaticobiliary ductal union in children with choledochal cysts., Subjects and Methods: Twenty children (age range, 1 month-13 years; mean age, 4.6 years; all girls) who were diagnosed with choledochal cyst by sonography underwent MR cholangiopancreatography with a single-shot fast spin-echo sequence. The type of choledochal cyst and anomalous pancreaticobiliary ductal union were characterized on the basis of MR cholangiopancreatographic findings and were compared with the finding of intraoperative cholangiography., Results: The type of choledochal cyst (type Ia, n = 4; type Ic, n = 7; type IVa, n = 7; type IVb, n = 2) determined on MR cholangiopancreatography correlated with that identified on intraoperative cholangiography in each patient. Anomalous pancreaticobiliary ductal union was detected by MR cholangiopancreatography and intraoperative cholangiography in 12 (60%) and 16 (80%) of 20 patients, respectively. The types of anomalous pancreaticobiliary ductal union as determined on MR cholangiopancreatography (type A, n = 2; type B, n = 7; type C, n = 3) were concordant with those of intraoperative cholangiography in 11 of 12 patients. In five of eight patients with choledochal cyst (type Ia, n = 1; type IVa, n = 5; type IVb, n = 2) in whom MR cholangiopancreatography could not depict anomalous pancreaticobiliary ductal union, anomalous pancreaticobiliary ductal union was documented on intraoperative cholangiography that was performed after choledochal cyst resection., Conclusion: MR cholangiopancreatography provides diagnostic information about anomalous pancreaticobiliary ductal union in children with choledochal cyst.