Localized cystic disease of the kidney in pediatric patients: Clinical and imaging findings with long term follow up.

INTRODUCTION: This study aimed to describe the clinical and imaging findings, including ultrasonography (US) findings, and long-term follow-up results in pediatric patients with localized cystic disease of the kidney (LCDK). MATERIAL AND METHODS: Retrospective review of pediatric patients diagnosed with LCDK based on imaging findings showing multiple localized renal cysts with intervening normal renal parenchyma from January 2002 to August 2020. Clinical presentations and US features of the affected and contralateral kidneys were reviewed and compared with computed tomography or magnetic resonance imaging findings, if available. RESULTS: A total of 18 patients (male:female = 11:7; median age, 8 years) were included. Initial clinical presentations were incidental findings (n = 5), abdominal pain (n = 5), or hematuria (n = 5). Of the seven patients (7/18, 39%) who showed multiple hyperechoic foci with ring-down artifacts within the cystic lesions on US, six patients showed focal calcification of the cysts on CT. Two patients (2/18, 11%) had milimetric cysts in the contralateral kidney. During follow-up (range, 2-122 months), there was an increase in lesion size, with ipsilateral renal growth in four patients (4/18, 22%). There was no renal function impairment at the initial presentation or during follow-up in all patients. CONCLUSIONS: LCDK can present with milimetric calcifications (39%), contralateral milimetric renal cysts (11%), and mild size increase during renal growth (22%) in children without renal function impairment. Follow-up US is recommended without surgical intervention in these typical cases.

Determining the optimal timing of screening spinal cord ultrasonography to detect filum terminale lipoma in infants.

PURPOSE: The purpose of this study was to identify the optimal timing for screening spinal cord ultrasonography (US) to detect filum terminale lipoma in infants. METHODS: We retrospectively reviewed infants (<12 months old) who underwent repeated spinal cord US between April 2011 and January 2019. We excluded infants if they only had one US examination, or if they had lesions other than filum terminale lipoma. Infants with filum terminale lipoma on magnetic resonance imaging were included in the lipoma group and the others in the control group. A linear mixed model was used to assess differences in the growth pattern of filum terminale thickness by age and group. The cutoff thickness on US and its diagnostic performance were assessed according to age. RESULTS: Among 442 infants with 901 US examinations, 46 were included in the lipoma group and 58 in the control group. Sixty-seven infants had unmeasurable filum terminale thickness on initial US, including 55 neonates (82.1%) before 1 month of age. The lipoma group had significantly greater filum terminale thickness than the control group (P<0.001). Thickness increased with age in the lipoma group (P=0.027). The sensitivity of US was 87.5% and the area under the receiver operating characteristic curve was 0.949 (95% confidence interval, 0.849 to 0.991) with a cutoff value of 1.1 mm in 4- to 6-month-old infants. CONCLUSION: Screening spinal cord US could effectively diagnose filum terminale lipoma in 4- to 6-month-old infants with a cutoff thickness of 1.1 mm. Spinal cord US can be used to screen young infants with intraspinal abnormalities.

Liver stiffness and perfusion changes for hepatic sinusoidal obstruction syndrome in rabbit model.

BACKGROUND: Hepatic sinusoidal obstruction syndrome (SOS) is caused by damage to hepatic sinusoidal endothelial cells that results in fibrous obliteration of intrahepatic venules and necrosis of hepatocytes. Currently the diagnosis is primarily based on nonspecific clinical features and invasive liver biopsy. Therefore, noninvasive imaging methods are required for the early diagnosis and severity assessment of hepatic SOS. AIM: To determine the effectiveness of supersonic shear wave imaging (SSI) and dual energy computed tomography (DECT) for diagnosing hepatic SOS using a rabbit model. METHODS: Among nine New Zealand white rabbits (3-4 kg, male), three in control group ingested normal saline for 20 d and six in the SOS group ingested 6-thioguanine (5 mg/kg/d) for 20 d. Liver stiffness was measured using SSI on days 0, 3, 10, and 20. On the same days, liver perfusion was evaluated from virtual monochromatic images of 55 keV and iodine map using DECT. Morphologic changes in the liver were assessed using CT. Final pathology scores were compared between the two groups. Liver stiffness and perfusion parameters were compared according to the groups, days, and pathology scores. RESULTS: Final pathology scores were significantly higher in the SOS than the control group (median 22 vs 2, P = 0.024). No gross morphologic changes were seen in livers. Liver stiffness, Hounsfield Unit values, and iodine concentrations were higher in the SOS compared to the control group on days 10 and 20 (all, P ≤ 0.007). Compared to day 0, liver stiffness and perfusion parameters were higher on day 20 in the SOS group (all, P ≤ 0.001). Correlation coefficients for liver stiffness (r = 0.635), Hounsfield Unit values (r = 0.587), and iodine concentration (r = 0.611) with final pathology scores were positive without significance (all, P > 0.05). CONCLUSION: Liver stiffness and perfusion parameters were significantly increased in the livers of a rabbit SOS model. SSI and DECT might aid in early diagnosis of hepatic SOS.

Hepatic subcapsular or capsular flow in biliary atresia: is it useful imaging feature after the Kasai operation?

OBJECTIVES: To evaluate the implications of hepatic subcapsular and capsular flows using ultrasonography (US) in children after Kasai operation. METHODS: Children who underwent liver US including color Doppler US and microvascular imaging (MVI) from May 2017 to October 2017 were retrospectively included. Children who underwent the Kasai operation for biliary atresia were included in the Kasai group and children with normal liver were included in the control group. Using US results, the number of intrahepatic biliary cysts and the maximum diameter of the spleen were evaluated in the Kasai group. Liver stiffness values were included when patients in the Kasai group had transient elastography (TE) or shear wave elastography (SWE) results. Hepatic subcapsular and capsular flows on color Doppler US and MVI were compared between the two groups using the following scores: 0, no flow reaching the hepatic capsule; 1, any flow reaching the hepatic capsule; and 2, contiguous hepatic capsular flow. The logistic regression test was used to identify associations between age, intrahepatic biliary cysts, spleen size, SWV, TE results, and flow scores measured on Doppler US and MVI in the Kasai group using the odds ratio (OR) and 95% confidence interval (CI). RESULT: A total of 65 children (mean 7.6 ± 5.3 years), 44 in the Kasai group and 21 in the control group, were included. In the control group, one child had score 1 on MVI and others had score 0 on both Doppler US and MVI. Among the Kasai group, 28 children (63.6%) had score 1, while others had score 0 using Doppler US. Using MVI, 24 children (54.5%) had score 2, 18 children had score 1, and one child had score 0. In the Kasai group, increased liver stiffness on TE was the only factor significantly associated with the presence of subcapsular flow on color Doppler US (OR 1.225, 95% CI 1.020-1.470) and increased spleen size was the only factor significantly associated with increased flow scores on MVI (OR 1.397, 95% CI 1.002-2.724). CONCLUSION: Detection of hepatic subcapsular, capsular flows on US would be meaningful for children after receiving the Kasai operation. KEY POINTS: • Hepatic subcapsular or capsular flows can be useful not only for the diagnosis but also for the postoperative follow-up in patients with biliary atresia. • Increased liver stiffness and splenomegaly after the Kasai operation were associated with presence of subcapsular or capsular flow on ultrasonography. • Evaluation of hepatic subcapsular and capsular flows could be needed to assess disease progression after receiving the Kasai operation.

Quantitative Imaging in Pediatric Hepatobiliary Disease.

Pediatric hepatobiliary imaging is important for evaluation of not only congenital or structural disease but also metabolic or diffuse parenchymal disease and tumors. A variety of ultrasonography and magnetic resonance imaging (MRI) techniques can be used for these assessments. In ultrasonography, conventional ultrasound imaging as well as vascular imaging, elastography, and contrast-enhanced ultrasonography can be used, while in MRI, fat quantification, T2/T2* mapping, diffusion-weighted imaging, magnetic resonance elastography, and dynamic contrast-enhanced MRI can be performed. These techniques may be helpful for evaluation of biliary atresia, hepatic fibrosis, nonalcoholic fatty liver disease, sinusoidal obstruction syndrome, and hepatic masses in children. In this review, we discuss each tool in the context of management of hepatobiliary disease in children, and cover various imaging techniques in the context of the relevant physics and their clinical applications for patient care.

Texture Analysis to Differentiate Malignant Renal Tumors in Children Using Gray-Scale Ultrasonography Images.

We assessed the feasibility of texture analysis to differentiate Wilms tumor, clear cell sarcoma and rhabdoid tumor of the kidney in children using gray-scale ultrasonography images. Children who had pre-operative renal ultrasonography images of the three tumors from January 2002 to February 2017 were retrospectively included as the test set, and children with the same criteria from March 2017 to December 2018 were included as the validation set. From histogram and second-order statistics, features were compared between the tumors, and diagnostic performances were assessed. Among a total of 32 children (24 children with Wilms tumors, five children with clear cell sarcomas and three children with rhabdoid tumors) from the test set, features from the second-order statistics showed an area under the curve greater than 0.89 for differentiating Wilms tumor from the others. These features aided in the differentiation of tumor type in the two children with Wilms tumors in the validation set. Therefore, texture analysis from gray-scale ultrasonography images can be used to differentiate Wilms tumors from clear cell sarcomas and rhabdoid tumors in children.

Predicting gastroesophageal varices through spleen magnetic resonance elastography in pediatric liver fibrosis.

BACKGROUND: A recent retrospective study confirmed that hepatic stiffness and splenic stiffness measured with magnetic resonance elastography (MRE) are strongly associated with the presence of esophageal varices. In addition, strong correlations have been reported between splenic stiffness values measured with MRE and hepatic venous pressure gradients in animal models. However, most studies have been conducted on adult populations, and previous pediatric MRE studies have only demonstrated the feasibility of MRE in pediatric populations, while the actual clinical application of spleen MRE has been limited. AIM: To assess the utility of splenic stiffness measurements by MRE to predict gastroesophageal varices in children. METHODS: We retrospectively reviewed abdominal MRE images taken on a 3T system in pediatric patients. Patients who had undergone Kasai operations for biliary atresia were selected for the Kasai group, and patients with normal livers and spleens were selected for the control group. Two-dimensional spin-echo echo-planar MRE acquisition centered on the liver, with a pneumatic driver at 60 Hz and a low amplitude, was performed to obtain hepatic and splenic stiffness values. Laboratory results for aspartate aminotransferase to platelet ratio index (APRI) were evaluated within six months of MRE, and the normalized spleen size ratio was determined with the upper normal size limit. All Kasai group patients underwent gastroesophageal endoscopy during routine follow-up. The Mann-Whitney U test, Kendall's tau b correlation and diagnostic performance analysis using the area under the curve (AUC) were performed for statistical analysis. RESULTS: The median spleen MRE value was 5.5 kPa in the control group (n = 9, age 9-18 years, range 4.7-6.4 kPa) and 8.6 kPa in the Kasai group (n = 22, age 4-18 years, range 5.0-17.8 kPa). In the Kasai group, the APRI, spleen size ratio and spleen MRE values were higher in patients with portal hypertension (n = 11) than in patients without (n = 11) (all P < 0.001) and in patients with gastroesophageal varices (n = 6) than in patients without (n = 16) (all P < 0.05), even though their liver MRE values were not different. The APRI (τ = 0.477, P = 0.007), spleen size ratio (τ = 0.401, P = 0.024) and spleen MRE values (τ = 0.426, P = 0.016) also correlated with varices grades. The AUC in predicting gastroesophageal varices was 0.844 at a cut-off of 0.65 (100% sensitivity and 75% specificity) for the APRI, and 0.844 at a cut-off of 9.9 kPa (83.3% sensitivity and 81.3% specificity) for spleen MRE values. CONCLUSION: At a cut-off of 9.9 kPa, spleen MRE values predicted gastroesophageal varices as well as the APRI and spleen size ratio in biliary atresia patients after the Kasai operation. However, liver MRE values were not useful for this purpose.

Head CT: Image quality improvement with ASIR-V using a reduced radiation dose protocol for children.

OBJECTIVE: To investigate the quality of images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V), using pediatric head CT protocols. METHODS: A phantom was scanned at decreasing 20% mA intervals using our standard pediatric head CT protocols. Each study was then reconstructed at 10% ASIR-V intervals. After the phantom study, we reduced mA by 10% in the protocol for <3-year-old patients and applied 30% ASIR-V and by 30% in the protocol for 3- to 15-year-old patients and applied 40% ASIR-V. RESULTS: Increasing the percentage of ASIR-V resulted in lower noise and higher contrast-to-noise ratio (CNR) and preserved spatial resolution in the phantom study. Compared to a conventional-protocol, reduced-dose protocol with ASIR-V achieved 12.8% to 34.0% of dose reduction and showed images of lower noise (9.22 vs. 10.73, P = 0.043) and higher CNR in different levels (centrum semiovale, 2.14 vs. 1.52, P = 0.003; basal ganglia, 1.46 vs. 1.07, P = 0.001; and cerebellum, 2.18 vs. 1.33, P < 0.001). Qualitative analysis showed higher gray-white matter differentiation and sharpness and preserved overall diagnostic quality in the images with ASIR-V. CONCLUSIONS: Use of ASIR-V allowed a 12.8% to 34.0% dose reduction in each age group with potential to improve image quality. KEY POINTS: • It is possible to reduce radiation dose and improve image quality with ASIR-V. • We improved noise and CNR and decreased radiation dose. • Sharpness improved with ASIR-V. • Total radiation dose was decreased by 12.8% to 34.0%.

Comparison of effective radiation doses from X-ray, CT, and PET/CT in pediatric patients with neuroblastoma using a dose monitoring program.

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.

The vagaries of proper imaging in diagnosing single-system ectopic ureter in children with continuous incontinence and outcomes of simple nephrectomy.

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.

Transforming growth factor-beta 1 in humidifier disinfectant-associated children's interstitial lung disease.

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.

Prepubertal Testicular Teratomas and Epidermoid Cysts: Comparison of Clinical and Sonographic Features.

OBJECTIVES: To evaluate clinical and sonographic features of testicular teratomas and epidermoid cysts in children and to assess differential points of immature teratomas from benign counterparts. METHODS: We retrospectively reviewed testicular teratomas and epidermoid cysts in children. Age at surgery, α-fetoprotein (AFP) level, and sonographic findings, including components (mainly cystic, mainly solid, or mixed), presence of calcification, and size, were reviewed. RESULTS: Nineteen cases were included, with 10 mature teratomas, 3 immature teratomas, and 6 epidermoid cysts. On sonography, most of the teratomas (n = 9) had mixed components, with 2 mainly cystic and 2 mainly solid lesions. The 2 mainly cystic teratomas underwent follow-up sonography and showed component changes to mainly solid. Compared to epidermoid cysts, teratomas were larger (P = .029) with less cystic components (P = .046). All 3 immature teratomas showed mixed components with calcification. In differentiating immature from benign teratomas, immature teratomas were larger (P= .047) in younger children (P= .008) with higher AFP levels (P= .023). The optimal cutoff values for diagnosing immature teratomas were 8 months of age, 23 ng/mL in AFP level, and 2.5 cm in size, with 100% sensitivity and 89.5% accuracy rates. However, sonographic features, including tumor components and presence of calcification, were not helpful for differentiating immature teratomas. CONCLUSIONS: Testicular masses in children younger than 8 months with AFP levels higher than 23 ng/mL and size larger than 2.5 cm need to be considered for orchiectomy rather than testis-sparing tumorectomy because of the increased frequency of immature teratomas versus mature teratomas or epidermoid cysts.

Optimal Filum Terminale Thickness Cutoff Value on Sonography for Lipoma Screening in Young Children.

OBJECTIVES: The purpose of this study was to evaluate the normal thickness of the filum terminale on sonography and suggest an optimal cutoff value for filum terminale lipoma screening in young children. METHODS: We retrospectively reviewed lumbosacral sonograms and magnetic resonance images from children younger than 36 months that were obtained between January 2013 and June 2014. The filum terminale thickness on sonography and the presence of fat in the filum terminale on magnetic resonance imaging were evaluated. RESULTS: From 111 children (mean age ± SD, 3.6 ± 3.0 months), 49 did not have abnormal lesions (normal group), and 62 had fat infiltration in the filum terminale (lipoma group). The filum terminale was thicker in the lipoma group than the normal group (1.5 ± 0.5 versus 0.9 ± 0.2 mm; P < .001). Filum terminale thickness also showed significance in a multivariable analysis with sex and age (odds ratio per 0.1-mm unit, 2.754; P < .001) and in propensity score matching for age (P < .001). The optimal cutoff value for filum terminale lipoma screening was 1.1 mm, with 94% sensitivity and 86% specificity. CONCLUSIONS: The conventional cutoff value of 2 mm for a thickened filum terminale on sonography can be too thick. We suggest an optimal cutoff value of 1.1 mm for lipoma screening in young children.

Conservative Management of Segmental Multicystic Dysplastic Kidney in Children.

OBJECTIVE: To assess the clinical characteristics and natural course of segmental multicystic dysplastic kidney (MCDK). METHODS: We retrospectively analyzed the medical records of 40 patients (43 renal units) diagnosed as having segmental MCDK between January 2002 and June 2014. Segmental MCDK was classified as typical when it was localized to the upper pole of a duplex collecting system, and otherwise as atypical. We investigated involution, associated anomalies requiring surgery, and complications of segmental MCDK. RESULTS: Of 43 renal units, 23 were typical and 20 were atypical. During 71.5 (interquartile range: 37.5-84.1) months of median follow-up period, complete and partial involution were observed in 48% and 26% of the typical group and 30% and 35% of the atypical group, respectively. In the typical group, involution was complete significantly earlier (P = .048) and ipsilateral anomalies were more frequently observed (P = .002). The initiation point of involution and contralateral anomalies were not different in the two groups. Hypertension developed in 1 case with contralateral MCDK and 1 case with contralateral renal agenesis. CONCLUSION: Segmental MCDK is not a rare disease entity, and conservative treatment appears to be sufficient with thorough follow-up, including regular monitoring of blood pressure and renal function, and with ultrasonography.

Is Increased Echogenicity Related to a Decrease in Glomerular Filtration Rate? Objective Measurements in Pediatric Solitary Kidney Patients--A Retrospective Analysis.

Quantitative measurements of renal echogenicity using a graphic program show close correlation with renal histology in adult patients, but this has neither been applied in pediatric patients nor correlated with glomerular filtration rate (GFR). To determine the direct relationship between echogenicity and GFR, we retrospectively analyzed 91 patients with a solitary functioning kidney under the age of 10, who underwent ultrasonography and serum cystatin C evaluation on a single day between January 2013 and December 2014. Echogenicity was quantified as previously reported. Echogenicity and kidney length were correlated with age-matched values of serum cystatin C-based GFR. Evaluation was performed at a median age of 17.1 months. GFR was low for age in eight of 54 right solitary kidney patients and four of 37 left solitary kidney patients. The right kidney-liver ratio was significantly elevated in the right decreased GFR group, while the left kidney-spleen ratio was not different in the left decreased GFR group. Age-matched longitudinal kidney length ratios were similar between the decreased and normal GFR groups for both sides. This is the first report to objectively prove the relationship between echogenicity and renal function in patients with a right solitary kidney. The right kidney-liver echogenicity ratio, measured objectively, showed feasibility in clinical practice as it showed a close relationship with decreased renal function when increased. However, absolute kidney echogenicity values, or the left kidney-spleen echogenicity ratio, were not independent markers for decreased renal function.

Choledochal cyst rupture with an intrahepatic pseudocyst mimicking hepatic mesenchymal hamartoma in an infant.

Spontaneous choledochal cyst rupture and consequent biliary peritonitis are rare in children. Here, we report a unique case of intrahepatic bile duct rupture of choledochal cyst type IV that resulted in loculated biliary peritonitis with an intrahepatic pseudocyst mimicking a hepatic mesenchymal hamartoma in a 3-month-old boy. Magnetic resonance cholangiopancreatography can help differentiate these conditions. Regardless of the location, pseudocysts resulting from biliary peritonitis should be considered in cases of choledochal cysts with adjacent fluid collection or cystic lesions.

Multiple hemangiomas of the urinary bladder in a child with gross hematuria.

We report a case of multiple hemangiomas involving the urinary bladder in a 4-year-old boy who presented with recurrent episodes of gross hematuria. On ultrasonography, compared with the bladder wall, the lesions presented as multiple isoechoic polypoid intraluminal masses with mildly increased vascularity on color Doppler exam. Cavernous hemangioma was confirmed by cold-cup biopsy, and the all lesions were coagulated with a Holmium laser. Despite their rarity, bladder hemangiomas should be included in the differential diagnosis of multiple intravesical masses in children with gross hematuria.

Radiation dose and image quality in pediatric chest CT: effects of iterative reconstruction in normal weight and overweight children.

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.

Meaning of ureter dilatation during ultrasonography in infants for evaluating vesicoureteral reflux.

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.

Radiation dose reduction and image quality in pediatric abdominal CT with kVp and mAs modulation and an iterative reconstruction technique.

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.