A regional brain volume-based age prediction model for neonates and the derived brain maturation index.

OBJECTIVE: To develop a postmenstrual age (PMA) prediction model based on segmentation volume and to evaluate the brain maturation index using the proposed model. METHODS: Neonatal brain MRIs without clinical illness or structural abnormalities were collected from four datasets from the Developing Human Connectome Project, the Catholic University of Korea, Hammersmith Hospital (HS), and Dankook University Hospital (DU). T1- and T2-weighted images were used to train a brain segmentation model. Another model to predict the PMA of neonates based on segmentation data was developed. Accuracy was assessed using mean absolute error (MAE), root mean square error (RMSE), and mean error (ME). The brain maturation index was calculated as the difference between the PMA predicted by the model and the true PMA, and its correlation with postnatal age was analyzed. RESULTS: A total of 247 neonates (mean gestation age 37 ± 4 weeks; range 24-42 weeks) were included. Thirty-one features were extracted from each neonate and the three most contributing features for PMA prediction were the right lateral ventricle, left caudate, and corpus callosum. The predicted and true PMA were positively correlated (coefficient = 0.88, p < .001). MAE, RMSE, and ME of the external dataset of HS and DU were 1.57 and 1.33, 1.79 and 1.37, and 0.37 and 0.06 weeks, respectively. The brain maturation index negatively correlated with postnatal age (coefficient = - 0.24, p < .001). CONCLUSION: A model that calculates the regional brain volume can predict the PMA of neonates, which can then be utilized to show the brain maturation degree. CLINICAL RELEVANCE STATEMENT: A brain maturity index based on regional volume of neonate's brain can be used to measure brain maturation degree, which can help identify the status of early brain development. KEY POINTS: • Neonatal brain MRI segmentation model could be used to assess neonatal brain maturation status. • A postmenstrual age (PMA) prediction model was developed based on a neonatal brain MRI segmentation model. • The brain maturation index, derived from the PMA prediction model, enabled the estimation of the neonatal brain maturation status.

Free-breathing contrast-enhanced upper abdominal MRI in children: comparison between Cartesian acquisition and stack-of-stars acquisition with two different fat-suppression techniques.

BACKGROUND: Respiratory artifacts impair image quality of magnetic resonance imaging (MRI) in children who cannot hold breath during MRI examination. PURPOSE: To compare the quality of free-breathing contrast-enhanced 3D T1-weighted (T1W) images of the upper abdomen in children using Cartesian acquisition (Cartesian eTHRIVE), stack-of-stars acquisition with spectral fat suppression (3D VANE eTHRIVE), and stack-of-stars acquisition with fat suppression using modified Dixon (3D VANE mDixon). MATERIAL AND METHODS: Pediatric patients (aged <19 years) who underwent whole-body MRI with free-breathing contrast-enhanced T1W axial scans of upper abdomen using Cartesian eTHRIVE, 3D VANE eTHRIVE, and 3D VANE mDixon were enrolled. Image quality parameters were assessed including overall image quality, hepatic edge sharpness, hepatic vessel clarity, respiratory artifacts, radial artifacts, lesion conspicuity, and lesion edge sharpness using the Likert scale, where a lower score indicated poorer image quality. The coefficients of variation of signal intensity of liver and spleen were analyzed. RESULTS: In 41 patients, 3D VANE eTHRIVE showed the highest scores for all image quality parameters (P ≤ 0.001). 3D VANE eTHRIVE also showed higher scores for respiratory (P ≤ 0.001) and radial artefacts than 3D VANE mDixon (P = 0.001). There were no significant differences in coefficients of variation of signal intensity of the liver and spleen between 3D VANE eTHRIVE and 3D VANE mDixon. Acquisition time was longer for 3D VANE eTHRIVE (81.26 ± 16 s) than for Cartesian eTHRIVE (7.87 ± 0.95 s) and 3D VANE mDixon (76.66 ± 12.4 s, P < 0.001). CONCLUSION: The application of stack-of-stars acquisition to 3D T1W abdominal MRI resulted in better image quality than Cartesian acquisition in free-breathing children. In stack-of-stars acquisition, spectral fat suppression resulted in better image quality and fewer artifacts than mDixon.

MRI Findings of Isolated Oculomotor Nerve Palsy after Mild Head Trauma in a Pediatric Patient: Case Report.

INTRODUCTION: Traumatic oculomotor nerve injury is usually caused by severe head trauma and is generally associated with other neurological deficits such as basilar skull fracture, orbital injury, or subarachnoid hemorrhage. Isolated traumatic oculomotor nerve injury after minor head trauma and its MRI findings are rarely reported. CASE PRESENTATION: We report a case of a 13-year-old girl with mydriasis, limited inferior and medial movement of the left eyeball, and left ptosis after a mild bump of the left forehead and eye into an electricity pole. The symptoms suggested left oculomotor nerve palsy, but initial facial computed tomography and brain MRI did not reveal any intracranial lesions or fractures in the skull and orbit. Cranial nerve MRI showed segmental hyperintensities and mild thickening of the left oculomotor nerve from the cavernous segment to the proximal orbital segment on T2 short tau inversion recovery and 3D fluid-attenuated inversion recovery volume isotropic turbo spin-echo acquisition sequences. The patient received treatment with oral pyridostigmine for 7 days and was fully recovered at 14 months after injury. DISCUSSION: As traumatic oculomotor nerve palsy can occur without intracranial hematomas or skull base fractures, routine brain MRI may not always reveal abnormalities; thus, MRI dedicated to imaging of the oculomotor nerve using FS T2WI and high-resolution 3D sequences can be helpful for the diagnosis and management of patients suspected of isolated oculomotor nerve injury.

Risk Estimation for Biliary Atresia in Patients with Neonatal Cholestasis: Development and Validation of a Risk Score.

Purpose To develop and validate a scoring system based on clinical and imaging features to predict the risk for biliary atresia in patients with neonatal cholestasis. Materials and Methods Patients with neonatal cholestasis who underwent both ultrasonography (US) and hepatobiliary scintigraphy (n = 480) were retrospectively identified from two tertiary referral hospitals from January 2000 to February 2017. Patients from one hospital were classified as the derivation cohort (n = 371), and those from the other hospital were classified as the validation cohort (n = 109). Clinical and imaging features associated with biliary atresia were assessed. Histopathologic or intraoperative cholangiographic findings served as the reference standard for biliary atresia. A prediction model was developed by using logistic regression and was then transformed into a scoring system. The scoring system was internally and externally validated. Results Among the 371 patients in the derivation cohort, 97 (26.15%) had biliary atresia. A scoring system was constructed with the following variables: full-term birth, presence of the triangular cord sign at US, abnormal gallbladder morphology at US, and failure of radioisotope excretion to the small bowel at hepatobiliary scintigraphy. The maximum possible score with this system is 7 points. This system enabled differentiation of biliary atresia in the derivation cohort (C statistic, 0.981; 95% confidence interval [CI]: 0.970, 0.992) and the validation cohort (C statistic, 0.995; 95% CI: 0.987, 1.000). The risk score also showed good calibration in both the derivation and the validation cohorts (P = .328 and P = .281, respectively). Conclusion A simple scoring system combining clinical and imaging features can help accurately estimate the risk for biliary atresia in patients with neonatal cholestasis.

Performance of MRI for suspected appendicitis in pediatric patients and negative appendectomy rate: A systematic review and meta-analysis.

PURPOSE: To evaluate in pediatric patients the diagnostic performance of magnetic resonance imaging (MRI) for suspected appendicitis and its negative appendectomy rate. MATERIALS AND METHODS: The study involved diagnostic accuracy studies that used MRI for pediatric patients with suspected appendicitis. Various field strengths and sequences were used in each included study. The diagnostic accuracy of MRI in pediatric patients with suspected appendicitis and negative appendectomy rate were assessed. A search of MEDLINE and EMBASE databases was performed until January 10, 2017. Two reviewers assessed the methodological quality of the articles using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Pooled sensitivity and specificity for appendicitis diagnosis were calculated using hierarchical logistic regression modeling. Meta-regression was performed to explore factors affecting study heterogeneity. The pooled negative appendectomy rate was analyzed. RESULTS: Thirteen original articles with 1946 patients were included. The summary sensitivity and specificity were 97% (95% confidence interval [CI], 95-98%) and 97% (95% CI, 93-98%), respectively; the area under the hierarchical summary receiver operating characteristic (HSROC) curve was 0.98 (95% CI, 0.97-0.99). In meta-regression, use of diffusion-weighted imaging (P < 0.01) and age (P < 0.01) affected heterogeneity, but there was no difference according to intravenous contrast agent use (P = 0.95). The pooled negative appendectomy rate of MRI was 4.5% (95% CI, 1.9-7.1%). CONCLUSION: MRI shows excellent diagnostic performance for appendicitis in pediatric patients regardless of the use of intravenous contrast media. Therefore, nonenhanced-only MRI protocols might be appropriate for pediatric patients with suspected appendicitis. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:767-778.

The diagnostic performance of shear-wave elastography for liver fibrosis in children and adolescents: A systematic review and diagnostic meta-analysis.

OBJECTIVE: To assess the diagnostic performance of shear-wave elastography for determining the severity of liver fibrosis in children and adolescents. METHODS: An electronic literature search of PubMed and EMBASE was conducted. Bivariate modelling and hierarchical summary receiver-operating-characteristic modelling were performed to evaluate the diagnostic performance of shear-wave elastography. Meta-regression and subgroup analyses according to the modality of shear-wave imaging and the degree of liver fibrosis were also performed. RESULTS: Twelve eligible studies with 550 patients were included. Shear-wave elastography showed a summary sensitivity of 81 % (95 % CI: 71-88) and a specificity of 91 % (95 % CI: 83-96) for the prediction of significant liver fibrosis. The number of measurements of shear-wave elastography performed was a significant factor influencing study heterogeneity. Subgroup analysis revealed shear-wave elastography to have an excellent diagnostic performance according to each degree of liver fibrosis. Supersonic shear imaging (SSI) had a higher sensitivity (p<.01) and specificity (p<.01) than acoustic radiation force impulse imaging (ARFI). CONCLUSIONS: Shear-wave elastography is an excellent modality for the evaluation of the severity of liver fibrosis in children and adolescents. Compared with ARFI, SSI showed better diagnostic performance for prediction of significant liver fibrosis. KEY POINTS: • Shear-wave elastography is beneficial for determining liver fibrosis severity in children. • Shear-wave elastography showed summary sensitivity of 81 %, specificity of 91 %. • SSI showed better diagnostic performance than ARFI for significant liver fibrosis.

The diagnostic performance of reduced-dose CT for suspected appendicitis in paediatric and adult patients: A systematic review and diagnostic meta-analysis.

OBJECTIVE: To evaluate the diagnostic performance of reduced-dose CT for suspected appendicitis. METHODS: A systematic search of the MEDLINE and EMBASE databases was carried out through to 10 January 2017. Studies evaluating the diagnostic performance of reduced-dose CT for suspected appendicitis in paediatric and adult patients were selected. Pooled summary estimates of sensitivity and specificity were calculated using hierarchical logistic regression modelling. Meta-regression was performed. RESULTS: Fourteen original articles with a total of 3,262 patients were included. For all studies using reduced-dose CT, the summary sensitivity was 96 % (95 % CI 93-98) with a summary specificity of 94 % (95 % CI 92-95). For the 11 studies providing a head-to-head comparison between reduced-dose CT and standard-dose CT, reduced-dose CT demonstrated a comparable summary sensitivity of 96 % (95 % CI 91-98) and specificity of 94 % (95 % CI 93-96) without any significant differences (p=.41). In meta-regression, there were no significant factors affecting the heterogeneity. The median effective radiation dose of the reduced-dose CT was 1.8 mSv (1.46-4.16 mSv), which was a 78 % reduction in effective radiation dose compared to the standard-dose CT. CONCLUSION: Reduced-dose CT shows excellent diagnostic performance for suspected appendicitis. KEY POINTS: • Reduced-dose CT shows excellent diagnostic performance for evaluating suspected appendicitis. • Reduced-dose CT has a comparable diagnostic performance to standard-dose CT. • Median effective radiation dose of reduced-dose CT was 1.8 mSv (1.46-4.16). • Reduced-dose CT achieved a 78 % dose reduction compared to standard-dose CT.

Diagnostic Performance of Transient Elastography for Liver Fibrosis in Children: A Systematic Review and Meta-Analysis.

OBJECTIVE: We aimed to assess the diagnostic performance of transient elastography for evaluating liver fibrosis in children and adolescents. MATERIALS AND METHODS: A computerized search of Medline and Embase up to December 31, 2017, was performed to identify studies. Studies evaluating the diagnostic performance of transient elastography for the severity of liver fibrosis in children and adolescents were selected. Pooled sensitivity and specificity were calculated using hierarchic logistic regression modeling. Multiple subgroup analysis was performed. RESULTS: In this meta-analysis that included 11 original articles involving 723 patients, transient elastography showed a summary sensitivity of 95% (95% CI, 74-99%) and a specificity of 90% (95% CI, 81-95%) for the diagnosis of significant liver fibrosis (stage ≥ F2) in children. The hierarchic summary ROC AUC was 0.96 (95% CI, 0.94-0.98). Multiple subgroup analysis for the diagnosis of significant hepatic fibrosis showed clinically acceptable ranges of sensitivity and specificity across all subgroups. In additional subgroup analysis, the diagnostic accuracies of transient elastography according to the Metavir system were also within a clinically acceptable range, measured up to a sensitivity of 86% and specificity of 86% for diagnosing Metavir stage F4 fibrosis. CONCLUSION: Transient elastography showed highly accurate diagnostic performance for the diagnosis of liver fibrosis in children.

Visibility of Normal Appendix on CT, MRI, and Sonography: A Systematic Review and Meta-Analysis.

OBJECTIVE: The purpose of the present study is to assess the visibility of the normal appendix on CT, MRI, or ultrasound (US) images of a healthy population. MATERIALS AND METHODS: The MEDLINE and EMBASE databases were searched to identify articles on the rates of detection of a normal appendix on CT, MRI, or US that appeared in the literature published up to January 20, 2017. Pooled detection rates were assessed using random-effects modeling, and rates associated with different imaging modalities were compared. Meta-regression analyses were performed to assess factors influencing detection rates and heterogeneity. RESULTS: Thirty-two studies (21 CT studies with 5296 patients, 7 MRI studies with 600 patients, and 4 US studies with 1221 patients) were included in our meta-analysis. The overall normal appendix detection rate tended to be highest for CT (84%), followed by US (71%) and MR (69%), but no statistically significant differences were noted (for CT vs MRI, p = 0.16; for CT vs US, p = 0.23; and for MRI vs US, p = 0.91). Meta-regression analyses of the appendix detection rate with CT revealed that the year of publication of the study, the number of CT channels, and slice thickness affected study heterogeneity. CONCLUSION: Normal appendixes seemed to be more visible on CT than on MRI or US, although this finding did not have statistical significance. With respect to CT, detection of normal appendixes was significantly better when more channels and thinner slices were used.

Sacrococcygeal teratomas in newborns: a comprehensive review for the radiologists.

Sacrococcygeal teratomas are the most common solid tumor in newborn infants. The diagnosis is not difficult in many cases; however, there should be additional information on imaging studies in order to manage those infants properly. Details include histology, morphologic classification, complications such as rupture, bleeding, and mass effects on the adjacent structures. Although imaging features cannot accurately predict the histologic subtypes of the tumors, thorough evaluation of the imaging features can help distinguish malignant tumors from benign tumors. In this article, pathogenesis, histological characteristics, clinical considerations, and morphologic characteristics will be discussed.

Rhabdomyosarcoma in Children and Adolescents: Patterns and Risk Factors of Distant Metastasis.

OBJECTIVE: The objective of this study is to evaluate patterns of distant metastasis and identified factors that may increase the risk of distant metastasis in pediatric patients with rhabdomyosarcoma. MATERIALS AND METHODS: This retrospective study included 69 patients (age, ≤ 20 years) who had rhabdomyosarcoma diagnosed between January 2000 and February 2016. Various imaging features, including distant metastasis, were evaluated on initial and follow-up imaging studies. Differences in the distribution of distant metastasis on the basis of the primary location were analyzed. Logistic regression analysis was performed to identify factors associated with distant metastasis. RESULTS: Twenty-six of the 69 patients (37.7%) had distant metastasis. Nineteen of the 26 patients had distant metastasis noted at initial presentation, and 15 of the 26 patients had new metastasis noted during follow-up. The most common site of metastasis was bone (n = 14), followed by lung (n = 12) and distant lymph nodes (n = 9). Lymph node metastasis more frequently developed in patients with primary rhabdomyosarcoma in an extremity than in patients with primary rhabdomyosarcoma that developed at other sites (p = 0.003). Of 15 patients who had metastasis during follow-up, nine (60%) did not appear to have simultaneous locoregional recurrence at the time of the discovery of distant metastasis. Older age at presentation and unfavorable sites of the primary tumor were significantly associated with distant metastasis in multivariate analysis. CONCLUSION: Distant metastasis of rhabdomyosarcomas in pediatric patients showed different patterns according to the location of the primary tumor and even occurred without local recurrence.

Computerized Bone Age Estimation Using Deep Learning Based Program: Evaluation of the Accuracy and Efficiency.

OBJECTIVE: The purpose of this study is to evaluate the accuracy and efficiency of a new automatic software system for bone age assessment and to validate its feasibility in clinical practice. MATERIALS AND METHODS: A Greulich-Pyle method-based deep-learning technique was used to develop the automatic software system for bone age determination. Using this software, bone age was estimated from left-hand radiographs of 200 patients (3-17 years old) using first-rank bone age (software only), computer-assisted bone age (two radiologists with software assistance), and Greulich-Pyle atlas-assisted bone age (two radiologists with Greulich-Pyle atlas assistance only). The reference bone age was determined by the consensus of two experienced radiologists. RESULTS: First-rank bone ages determined by the automatic software system showed a 69.5% concordance rate and significant correlations with the reference bone age (r = 0.992; p < 0.001). Concordance rates increased with the use of the automatic software system for both reviewer 1 (63.0% for Greulich-Pyle atlas-assisted bone age vs 72.5% for computer-assisted bone age) and reviewer 2 (49.5% for Greulich-Pyle atlas-assisted bone age vs 57.5% for computer-assisted bone age). Reading times were reduced by 18.0% and 40.0% for reviewers 1 and 2, respectively. CONCLUSION: Automatic software system showed reliably accurate bone age estimations and appeared to enhance efficiency by reducing reading times without compromising the diagnostic accuracy.

Diagnostic Performance of Sonographic Features in Patients With Biliary Atresia: A Systematic Review and Meta-analysis.

OBJECTIVES: To evaluate the diagnostic performance of sonographic features of biliary atresia in patients with infantile cholestasis. METHODS: The Ovid-MEDLINE and EMBASE databases were searched for studies of the diagnostic performance of sonographic features of biliary atresia in patients with infantile cholestasis. A meta-analysis was performed to evaluate the diagnostic performance of the triangular cord sign and other sonographic features in patients with biliary atresia. RESULTS: Seventeen eligible studies with 1444 patients were included. The triangular cord sign had high accuracy for diagnosing biliary atresia: the meta-analytic summary sensitivity and specificity were 85% (95% confidence interval, 77%-90%) and 97% (95% confidence interval, 94%-99%), respectively. The area under the hierarchical summary receiver operating characteristic curve was 0.97. Meta-regression analysis revealed that the cutoff thickness of the triangular cord sign (3 or 4 mm) was a significant factor affecting study heterogeneity (P < .01). The proportions of nonidentification of the gallbladder (GB) ranged from 0% to 53%. Abnormal GB morphologic characteristics, nonvisualization of the common bile duct, and the presence of hepatic subcapsular flow showed relatively high sensitivities and specificities. CONCLUSIONS: The triangular cord sign and other sonographic features, including abnormal GB morphologic characteristics, nonvisualization of the common bile duct, and the presence of hepatic subcapsular flow, had high diagnostic performance for the diagnosis of biliary atresia.

Bone Age Assessment Using Artificial Intelligence in Korean Pediatric Population: A Comparison of Deep-Learning Models Trained With Healthy Chronological and Greulich-Pyle Ages as Labels.

OBJECTIVE: To develop a deep-learning-based bone age prediction model optimized for Korean children and adolescents and evaluate its feasibility by comparing it with a Greulich-Pyle-based deep-learning model. MATERIALS AND METHODS: A convolutional neural network was trained to predict age according to the bone development shown on a hand radiograph (bone age) using 21036 hand radiographs of Korean children and adolescents without known bone development-affecting diseases/conditions obtained between 1998 and 2019 (median age [interquartile range {IQR}], 9 [7-12] years; male:female, 11794:9242) and their chronological ages as labels (Korean model). We constructed 2 separate external datasets consisting of Korean children and adolescents with healthy bone development (Institution 1: n = 343; median age [IQR], 10 [4-15] years; male: female, 183:160; Institution 2: n = 321; median age [IQR], 9 [5-14] years; male: female, 164:157) to test the model performance. The mean absolute error (MAE), root mean square error (RMSE), and proportions of bone age predictions within 6, 12, 18, and 24 months of the reference age (chronological age) were compared between the Korean model and a commercial model (VUNO Med-BoneAge version 1.1; VUNO) trained with Greulich-Pyle-based age as the label (GP-based model). RESULTS: Compared with the GP-based model, the Korean model showed a lower RMSE (11.2 vs. 13.8 months; P = 0.004) and MAE (8.2 vs. 10.5 months; P = 0.002), a higher proportion of bone age predictions within 18 months of chronological age (88.3% vs. 82.2%; P = 0.031) for Institution 1, and a lower MAE (9.5 vs. 11.0 months; P = 0.022) and higher proportion of bone age predictions within 6 months (44.5% vs. 36.4%; P = 0.044) for Institution 2. CONCLUSION: The Korean model trained using the chronological ages of Korean children and adolescents without known bone development-affecting diseases/conditions as labels performed better in bone age assessment than the GP-based model in the Korean pediatric population. Further validation is required to confirm its accuracy.

Prevalence and MRI findings of incidentally detected pituitary non-enhancing lesion on brain MRI in children.

OBJECTIVES: To determine the prevalence and MRI findings of incidentally detected pituitary nonenhancing lesion on brain MRI in children, and to compare the detection rates of pituitary nonenhancing lesion according to magnetic field strength and acquisition technique. METHODS: Pediatric patients (≤18 years old) who underwent brain MRI with contrast-enhancement between January 2018 and September 2019 were retrospectively included (n=365). The presence, size, and signal intensity of pituitary nonenhancing lesions were assessed by two radiologists. The prevalence of pituitary nonenhancing lesions was compared between different magnetic field strengths and MRI acquisition techniques. RESULTS: Pituitary nonenhancing lesions were identified in 76 patients (20.8%). The anteroposterior diameter of pituitary nonenhancing lesion was the smallest diameter in most patients (93.4%; mean diameter ± SD of 2.4 ± 1.5 mm; range: 0.9-9.0 mm). Sixty-seven percent of the pituitary nonenhancing lesions were hypointense on T1-weighted imaging, 44.1% were hyperintense on T2-weighted imaging, and 12.9% showed low signal intensity on susceptibility-weighted imaging. There was no diffusion restriction in any of the nonenhancing lesions. There was no significant difference in the prevalence of pituitary nonenhancing lesions according to magnetic field strength, age, gender, slice thickness, or 2D vs. 3D contrast-enhanced T1-weighted imaging sequence. CONCLUSIONS: Pituitary nonenhancing lesions were identified on contrast-enhanced brain MRI in 20.8% of pediatric patients, with no significant difference in the prevalence according to magnetic field strength, slice thickness, and 2D or 3D contrast-enhanced T1-weighted imaging.

Comparison of whole-body MRI, bone scan, and radiographic skeletal survey for lesion detection and risk stratification of Langerhans Cell Histiocytosis.

Accurate risk stratification according to the extent of Langerhans cell histiocytosis (LCH) determined on whole-body evaluation is important for determining the treatment plans and prognosis in patients with LCH. This study aimed to compare the lesion detectability and the accuracy of risk stratification of skeletal survey, bone scan, and whole-body magnetic resonance imaging (WB-MRI) in patients with LCH. Patients with newly-diagnosed LCH who underwent all three imaging modalities were retrospectively included (n = 46). The sensitivity and mean number of false-positives per patient for LCH lesions, and the accuracy of risk stratification of each modality were assessed. WB-MRI had significantly higher sensitivity (99.0%; 95% confidence interval, 93.2-99.9%) than skeletal survey (56.6%; p < 0.0001) and bone scan (38.4%; p < 0.0001) for LCH lesions, and there were no significant differences in the number of false-positives per patient (p > 0.017). WB-MRI tended to have higher accuracy for the risk stratification than skeletal survey and bone scan (concordance rate of 0.98, 0.91, and 0.83, respectively), although the differences were not significant (overall p-value 0.066). In conclusion, WB-MRI had higher detectability for LCH lesions than skeletal survey and bone scan, while the three whole-body imaging modalities had comparable accuracy in the initial risk stratification of LCH.

Whole Body MR Imaging: A Useful Imaging Modality in the Management of Children With Acute Myeloid Leukemia.

INTRODUCTION: To evaluate the distribution of chloromas using whole body magnetic resonance (MR) imaging in pediatric patients with acute myeloid leukemia (AML) and to assess the clinical role of whole body MR imaging in management of pediatric patients with AML. MATERIALS AND METHODS: We retrospectively searched pediatric patients (< 18 years old) who were diagnosed with AML and underwent whole body MR imaging during their illness between January 2006 and December 2014. The presence of chloromas was defined as when it was proven pathologically or showed typical imaging features. Nonchloroma lesions that were incidentally detected and were not previously seen on other imaging studies were defined as clinically occult nonchloroma lesions. RESULTS: Sixty-nine whole body MR scans of 40 patients with AML were included. The musculoskeletal system (42.9%) was the most commonly affected by chloromas. A total of 77 chloromas were identified in 11 (27.5%) of 40 patients. Nine (81.8%) of these 11 patients had 2 or more chloromas. There were 39 (50.6%) unexpected chloromas, which were incidentally detected, in 7 patients. Whole body MR scanning provided additional information regarding 21 clinically occult nonchloroma lesions in this patient population. CONCLUSION: Chloromas tended to show multiplicity and be present without symptoms. The most common site of involvement was the musculoskeletal system. Whole body MR imaging provided additional information that affected the clinical management of children with AML.

Diagnostic Performance of Magnetic Resonance Enterography for Detection of Active Inflammation in Children and Adolescents With Inflammatory Bowel Disease: A Systematic Review and Diagnostic Meta-analysis.

Importance: Magnetic resonance (MR) enterography has the advantage over other techniques of being noninvasive, lacking ionizing radiation, and demonstrating excellent soft-tissue contrast to evaluate pediatric patients with inflammatory bowel disease (IBD). Objective: To evaluate the diagnostic performance of MR enterography for detection of active inflammation in children and adolescents with known or suspected IBD. Data Sources: A search of MEDLINE and EMBASE up to January 2, 2017, was performed to identify studies. Search terms included child, pediatric, adolescent, Crohn disease, inflammatory bowel disease, and magnetic resonance enterography. The search was limited to English-language publications. Study Selection: Studies evaluating the diagnostic performance of MR enterography for detection of active inflammation in pediatric patients with known or suspected IBD were selected. Two reviewers independently assessed the eligibility of the selected articles. Data Extraction and Synthesis: The study was performed and reported in accordance with the PRISMA guidelines. Pooled summary estimates of sensitivity and specificity were calculated using hierarchical logistic regression modeling. Main Outcomes and Measures: The diagnostic performance of MR enterography for detection of active inflammation in pediatric patients with known or suspected IBD was the primary outcome. Subgroup analyses and meta-regression were performed. Results: Eighteen original articles involving a total of 687 patients were included. The summary sensitivity was 83% (95% CI, 75%-89%), the summary specificity was 93% (95% CI, 90%-95%), and the area under the hierarchical summary receiver operating characteristic curve was 0.95 (95% CI, 0.93-0.97). The Higgins I2 statistics demonstrated substantial heterogeneity in terms of sensitivity (I2 = 84.1%) and specificity (I2 = 68.8%). Based on per-patient analysis, the summary sensitivity was 86% (95% CI, 78%-91%) and specificity was 91% (95% CI, 82%-96%). In meta-regression, among the various potential covariates, scanner manufacturer was associated with study heterogeneity. Conclusions and Relevance: Magnetic resonance enterography, which is a noninvasive, radiation-free modality, demonstrates high diagnostic performance in the diagnosis of active inflammation in pediatric patients with IBD, especially at the per-patient level.

Real-time two-dimensional Shear-wave elastography for liver stiffness in children: Interobserver variation and effect of breathing technique.

OBJECTIVES: To evaluate interobserver variation and to assess the effect of the breathing technique on liver stiffness (LS) measurement using real-time two-dimensional shear-wave elastography (2D-SWE) in children. METHODS: Patients who underwent real-time 2D-SWE by two operators (group 1) and patients who underwent real-time 2D-SWE by one operator using the free-breathing and breath-holding techniques (group 2) were included. In group 1, interobserver agreement was assessed using the intraclass correlation coefficient (ICC) and the 95% limits-of-agreement was analyzed to evaluate the maximum change in the LS values based on Bland-Altman analysis. In group 2, the Bland-Altman plot and the paired t-test were used to determine the effect of breathing technique on LS measurement. RESULTS: The interobserver agreement of the LS measurement in group 1 (n=63) was excellent (ICC, 0.953), and the 95% limits-of-agreement was 31.8% of the mean LS values. In group 2 (n=45), the free-breathing technique revealed systematically lower LS with a mean difference of -11.1% of the mean LS values, compared to the breath-holding technique (P=0.016). CONCLUSION: LS measurement assessed by real-time 2D-SWE in children showed excellent interobserver agreement. Changes in LS values less than 31.8% of the mean LS values may represent the measurement error. The free-breathing technique showed lower LS values, compared to the breath-holding technique.