Basics for Pediatric Brain Tumor Imaging: Techniques and Protocol Recommendations.

This review provides an overview of the current state of pediatric brain tumor imaging, emphasizing the role of various imaging sequences and highlighting the advantages of standardizing protocols for pediatric brain tumor imaging in diagnosis and treatment response evaluation. Basic anatomical sequences such as pre- and post-contrast 3D T1-weighted, T2-weighted, fluid-attenuated inversion recovery, T2*-weighted, and diffusion-weighted imaging (DWI), are fundamental for assessing tumor location, extent, and characteristics. Advanced techniques like DWI, diffusion tensor imaging, perfusion imaging, magnetic resonance spectroscopy, and functional MRI offer insights into cellularity, vascularity, metabolism, and function. To enhance consistency and quality, standardized protocols for pediatric brain tumor imaging have been recommended by expert groups. Special considerations for pediatric patients, including the minimization of anesthesia exposure and gadolinium contrast agent usage, are essential to ensure patient safety and comfort. Staying up-to-date with diagnostic imaging techniques can contribute to improved communication, outcomes, and patient care in the field of pediatric neurooncology.

Application of the postnatal urinary tract dilation classification system to predict the need for surgical intervention among neonates and young infants.

PURPOSE: The aim of this study was to validate the postnatal urinary tract dilation (UTD) classification system by correlating it with the need for surgical intervention. METHODS: Young infants who underwent ultrasound (US) examinations for prenatal hydronephrosis were retrospectively identified. The kidney units (KUs; right, left, or bilateral) were graded from UTD P0 (very low risk) to P3 (high risk) based on seven US criteria from the UTD system. Surgery-free survival curves were constructed using the Kaplan-Meier method. Univariable and multivariable Cox proportional-hazards regression analysis clustered by patients was performed. Interobserver agreement was analyzed using the weighted kappa coefficient. RESULTS: In total, 504 KUs from 336 patients (mean age, 18.3±15.9 days; range, 1 to 94 days; males, n=276) were included, with a median follow-up of 24.2 months. Fifty-eight KUs underwent surgical intervention. Significant differences were observed among the Kaplan-Meier curves stratified into UTD groups (P<0.001). The presence of anterior-posterior renal pelvic diameter ≥15 mm (hazard ratio [HR], 8.602; 95% confidence interval [CI], 1.558 to 43.065), peripheral calyceal dilation (HR, 8.190; 95% CI, 1.558 to 43.065), ureteral dilation (HR, 2.619; 95% CI, 1.274 to 5.380), parenchymal thickness abnormality (HR, 3.371; 95% CI, 1.574 to 7.223), bladder abnormality (HR, 12.209; 95% CI, 3.616 to 41.225) were significantly associated with the occurrence of surgery. The interobserver agreement was moderate to almost perfect agreement for US features (κ=0.564-0.898) and substantial for final UTD grades (κ=0.716). CONCLUSION: The UTD classification system is reliable and appropriately stratifies the risk of surgical intervention.

Diagnostic performance of the 2021 Korean thyroid imaging reporting and data system in pediatric thyroid nodules.

OBJECTIVES: To evaluate the diagnostic performance of 2021 K-TIRADS biopsy criteria for detecting malignant thyroid nodules in a pediatric population, making comparisons with 2016 K-TIRADS. METHODS: This retrospective study included pediatric patients with histopathologically confirmed diagnoses. The diagnostic performance of 2021 K-TIRADS was compared with that of 2016 K-TIRADS. Simulation studies were performed by changing biopsy cut-off sizes for K-TIRADS 5 to 1.0 cm (K-TIRADS5-1.0cm) and 0.5 cm (K-TIRADS5-0.5cm), and for K-TIRADS 4 to 1.0 cm (K-TIRADS4-1.0cm) and 1.0-1.5 cm (K-TIRADS4-1.0~1.5cm). Subgroup analysis was performed in small (< 1.5 cm) and large nodules (≥ 1.5 cm). RESULTS: Two hundred seventy-seven thyroid nodules (54.9% malignant) from 221 pediatric patients were analyzed. All simulated 2021 K-TIRADS showed higher accuracy than 2016 K-TIRADS. Compared with 2021 K-TIRADS5-1.0cm, 2021 K-TIRADS5-0.5cm showed lower specificity (51.6% vs. 47.9%; p = 0.004) but higher sensitivity (77.2% vs. 90.3%; p < 0.001) and accuracy (62.7% vs. 68.9%; p < 0.001). Compared with 2021 K-TIRADS4-1.0cm, 2021 K-TIRADS4-1.0~1.5cm showed higher specificity (44.9% vs. 47.9%; p = 0.018) without significant difference in other diagnostic measures. Compared with 2016 K-TIRADS, 2021 K-TIRADS (biopsy cut-offs, 0.5 cm for K-TIRADS 5; 1.0-1.5 cm for K-TIRADS 4) showed higher sensitivity (34.0% vs. 67.3%; p < 0.001) while maintaining specificity (89.4% vs. 88.2%; p = 0.790) in small nodules, and higher specificity (5.9% vs. 25.4%; p < 0.001) while maintaining sensitivity (100% vs. 98.7%; p = 0.132) in large nodules. CONCLUSIONS: In pediatric patients, 2021 K-TIRADS showed superior diagnostic accuracy to 2016 K-TIRADS, especially with a biopsy cut-off of 0.5 cm for K-TIRADS 5 and 1.0-1.5 cm for K-TIRADS 4. KEY POINTS: • All simulated 2021 K-TIRADS showed higher accuracy than 2016 K-TIRADS. • 2021 K-TIRADS with cut-off size for K-TIRADS 5 of 0.5 cm showed lower specificity but higher sensitivity and accuracy than that of 1.0 cm. • Compared with 2016 K-TIRADS, 2021 K-TIRADS (biopsy cut-offs, 0.5 cm for K-TIRADS 5; 1.0-1.5 cm for K-TIRADS 4) showed higher sensitivity while maintaining specificity in small nodules, and higher specificity while maintaining sensitivity in large nodules.

Diagnostic Performance of Five Adult-based US Risk Stratification Systems in Pediatric Thyroid Nodules.

Background The validation of adult-based US risk stratification systems (RSSs) in the discrimination of malignant thyroid nodules in a pediatric population remains lacking. Purpose To estimate and compare the diagnostic performance of pediatric US RSSs based on five adult-based RSSs in the discrimination of malignant thyroid nodules in a pediatric sample. Materials and methods Pediatric patients (age ≤18 years) with histopathologically confirmed US-detected thyroid nodules at a tertiary referral hospital between January 2000 and April 2020 were analyzed retrospectively. The diagnostic performance of US-based fine-needle aspiration biopsy (FNAB) criteria in thyroid cancer detection was estimated. The following sensitivity analyses were performed: (a) scenario 1: nodules smaller than 1 cm, with the highest category additionally biopsied; (b) scenario 2, application of American College of Radiology Thyroid Imaging Reporting and Data System nodule size cutoffs to other RSSs; (c) scenario 3, scenarios 1 and 2 together. Generalized estimating equations (GEEs) were used for estimation. Results A total of 277 thyroid nodules in 221 pediatric patients (median age, 16 years [interquartile range {IQR}, 13-17]; 172 female; 152 of 277 patients [55%] malignant) were analyzed. The GEE-estimated sensitivity and specificity ranged from 70% to 78% (104 to 119 of 152 patients, based on each reader's interpretation) and from 42% to 78% (49 of 124 patients to 103 of 125 patients). In scenario 1, the missed malignancy rate was reduced from 32%-38% (41 of 134 patients to 34 of 83 patients) to 15%-21% (eight of 59 patients to 28 of 127 patients). In scenario 2, the unnecessary biopsy rate was reduced from 35%-39% (60 of 176 patients to 68 of 175 patients) to 20%-34% (18 of 109 patients to 62 of 179 patients). The highest accuracy was noted in scenario 3 (range, 71%-81%; 199 of 277 patients to 216 of 262 patients). Conclusion The diagnostic performances of the fine-needle aspiration biopsy criteria of five adult-based risk stratification systems were acceptable in the pediatric population and were improved by applying the American College of Radiology Thyroid Imaging Reporting and Data System size cutoff for nodules 1 cm or larger and allowing biopsy of the highest category nodules smaller than 1 cm. © RSNA, 2022 Online supplemental material is available for this article.

Neoplastic Etiology and Natural Course of Pituitary Stalk Thickening.

CONTEXT: Pituitary stalk thickening (PST) is often identified on magnetic resonance imaging (MRI), either incidentally or during diagnostic workup of hypopituitarism. However, the neoplastic etiology and natural course of PST are not fully understood, although this knowledge is required to establish diagnostic and surveillance strategies. OBJECTIVE: This work aimed to investigate the neoplastic etiology and natural course of PST. METHODS: MEDLINE/PubMed and EMBASE databases were searched up to February 2021 to identify original research investigating the etiologies of PST. The proportion of neoplastic etiology in patients with PST was meta-analytically pooled. Supplementary analysis exploring factors suggesting neoplasm was also performed. For initially indeterminate cases without confirmed diagnosis, the proportion of patients showing progression of PST during follow-up was evaluated. RESULTS: Eighteen studies covering 1368 patients with PST were included. The pooled proportion of neoplasm was 45.2% (95% CI, 33.3%-57.8%), with substantial heterogeneity across studies (I2 = 93%). The most common neoplasm was germ cell tumor (14.0% of study population), followed by Langerhans cell histiocytosis (10.2%) and metastasis (4.7%). The studies on pediatric populations and those with more than 50% of patients having at least one pituitary hormone deficiency tended to show a higher proportion of neoplasm. The pituitary stalk was thicker in neoplasms, but the difference was not significant (pooled mean difference, 2.08 mm; P = .08). In initially indeterminate cases, 18.5% (95% CI, 7.6%-38.3%) showed progression of PST during follow-up. CONCLUSION: PST was commonly confirmed to be neoplastic, especially in pediatric populations. As isolated PST frequently progresses, follow-up imaging is essential in initially indeterminate cases.

Outcome of staging chest CT and identification of factors associated with lung metastasis in children with hepatoblastoma.

OBJECTIVES: To evaluate the outcome of staging chest CT and to identify clinicoradiological factors predictive of lung metastasis in patients with hepatoblastoma based on the 2017 PRE-Treatment EXTent of tumor (PRETEXT) system. METHODS: This bi-center study retrospectively identified patients diagnosed with hepatoblastoma between January 1998 and September 2019 in two tertiary hospitals. The primary outcome was the proportion of the patients who had lung metastasis at staging chest CT. The diagnostic accuracy of staging chest CT was calculated based on the 2017 PRETEXT criteria. The secondary outcome was the identification of factors predictive of lung metastasis using multivariable logistic regression. RESULTS: In total, 123 patients (median age, 1 year; interquartile range, 0-4 years; 59 female) were included. Among those, 28% (35/123; 95% confidence interval [CI], 21-37%) had lung metastasis at staging chest CT. The overall accuracy of staging chest CT was 96.8%. The proportion of lung metastasis in patients with stage I, II, III, and IV was 0%, 24% (12 of 49; 95% CI, 14-38%), 23% (9 of 40; 95% CI, 12-38%), and 56% (14 of 25; 95% CI, 37-73%), respectively. Multifocality (adjusted odds ratio, 6.7; 95% CI, 2.7-17.5; p < .001) and male sex (adjusted odds ratio, 3.1; 95% CI, 1.2-8.6; p = .02) were associated with the presence of lung metastasis. CONCLUSIONS: Twenty-eight percent of the patients with hepatoblastoma had lung metastasis at staging chest CT. Multifocality and male sex were predictive factors for lung metastasis on staging chest CT. KEY POINTS: • The proportion of lung metastasis in patients with hepatoblastoma was 28%. • The overall accuracy of staging chest CT was 97% based on the 2017 PRETEXT system. • Hepatic tumor multifocality and male sex were predictors of lung metastasis.

Diagnostic performance of adult-based ATA and ACR-TIRADS ultrasound risk stratification systems in pediatric thyroid nodules: a systematic review and meta-analysis.

OBJECTIVES: To evaluate the diagnostic performance of adult-based "American College of Radiology- Thyroid Imaging Reporting And Data System" (ACR-TIRADS) and "American Thyroid Association" (ATA) in the pediatric population. METHODS: MEDLINE/PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for articles investigating the diagnostic performance of each stratification system (ACR-TIRADS or ATA) and evaluated them according to three aspects: (a) the risk of malignancy in each category; (b) diagnostic performance using the classic indicators (sensitivity, specificity); and (c) diagnostic performance regarding fine needle aspiration/biopsy recommendation. In addition to pathologic diagnosis, we allowed imaging follow-up as the reference standard for benign nodules. RESULTS: Eight articles (1036 thyroid nodules) were included. For ACR-TIRADS, the pooled risk of malignancy in category was as follows: category 5 (59.3%); 4 (20.7%); 3 (11.0%); 2 (6.0%), and 1 (5.5%). For nodules of high suspicion of malignancy (category 4 or 5), the pooled sensitivity and specificity were 0.84 and 0.64. For ATA, the pooled risk of malignancy was as follows: category 5 (55.4%); 4 (34.2%); 3 (12.2%); and 2 (7.5%). For nodules of high suspicion of malignancy (category 4 or 5), the pooled sensitivity and specificity were 0.90 and 0.50. For category 5 nodules, the pooled specificity was significantly higher in ACR-TIRADS (p = 0.02). For ACR-TIRADS, the missed malignancy rate was 21.7% and the unnecessary biopsy rate was 62.7%. Information was not sufficient for this calculation with ATA. CONCLUSIONS: The diagnostic performance of ACR-TIRADS and ATA in the pediatric population was somewhat modest. Large studies are mandatory for further validation and future amendments. KEY POINTS: • The pooled sensitivity and specificity for highly suspicious nodules (category 4 or 5) for ACR-TIRADS were 0.84 and 0.64, and for ATA were 0.90 and 0.50, respectively. • When applying ACR-TIRADS for children, the pooled missed malignancy rate (21.7%) and unnecessary biopsy rates (62.7%) are still reasonably high. Insufficient information was available to perform these calculations for the ATA system. • Current risk stratification systems, especially ACR-TIRADS, require modification by focusing more on increasing the sensitivity and decreasing the missed malignancy rate. Lowering size cut-off for biopsy would be a reasonable option.

Ability of Pelvic Magnetic Resonance Imaging to Predict Clinical Course of Perianal Fistula in Paediatric Crohn's Disease Patients.

BACKGROUND AND AIMS: Evidence is limited regarding clinical course and magnetic resonance imaging [MRI] features of perianal fistula [PAF] in Korean children with Crohn's disease [CD]. We investigated MRI features of PAF and associations with long-term outcomes. METHODS: We retrospectively analysed 243 patients with pelvic MRI for diagnosis of CD. Incidence of clinically evident PAF at diagnosis was determined, as were the proportions of patients with clinical failure [failure to achieve fistula healing within 1 year] and recurrence [new/recurrent PAF after fistula healing within 1 year]. Associations between outcomes and MRI features, specified in modified Van Assche index and MAGNIFI-CD, were evaluated. Associations between later development of clinically evident PAF and subclinical PAF detected on MRI at diagnosis were evaluated. RESULTS: Among 243 included patients, 108 [44.4%] and 76 [31.3%] had clinically evident and subclinical PAF at diagnosis, respectively; 66.4% of the patients with clinically evident PAF achieved fistula healing within 1 year, and 32.7% of those patients developed recurrence. Fistula length and dominant features of the tracts were associated with clinical failure, and fistula length was associated with recurrence. Clinically evident PAF developed in 17.0% of the patients without clinically evident PAF at diagnosis. We did not find statistically significant association between subclinical PAF and later development of clinically evident PAF [adjusted hazard ratio, 2.438; p = 0.15]. CONCLUSIONS: A considerable proportion of Korean paediatric CD patients had clinically evident and subclinical PAF. Fistula length and dominant feature of the tract on MRI are useful predictors of outcomes.

Incidence of Occult Spinal Dysraphism Among Infants With Cutaneous Stigmata and Proportion Managed With Neurosurgery: A Systematic Review and Meta-analysis.

Importance: Occult spinal dysraphism (OSD) is the most common congenital spinal anomaly. Cutaneous anomalies such as skin dimples or deviated gluteal folds are well known as stigmata of OSD and are indicators for further evaluation; however, the association between cutaneous anomalies and OSD has not been systemically evaluated. Objective: To evaluate the incidence of OSD and the proportion of OSD cases managed with a neurosurgical intervention among neonates or infants with various cutaneous stigmata. Data Sources: PubMed and Embase databases were searched for studies published up to July 25, 2018, that evaluated the proportion of OSD cases in neonates or infants with cutaneous stigmata. Search terms included ultrasound, dysraphism, dimple, and infant or neonate. The search was limited to English-language publications. Study Selection: Two reviewers selected the studies evaluating the incidence of OSD among neonates or infants with cutaneous stigmata. Data Extraction and Synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for data extraction were followed. Pooled proportions of OSD cases and OSD cases that were managed with a neurosurgical intervention were obtained using the generalized linear mixed model and maximum likelihood method. Main Outcome and Measures: The pooled incidence of OSD and OSD cases managed with neurological surgery among patients with cutaneous stigmata was the primary outcome. This outcome was also evaluated in each subgroup, and heterogeneity was explored using subgroup analysis. Results: A total of 15 studies, involving 6558 neonate or infant patients with various cutaneous stigmata, were included. The pooled proportion of OSD cases among the patients with cutaneous stigmata was 2.8% (95% CI, 2.1%-3.8%; I2 = 51.6%), and the proportion managed with neurological surgery was 0.6% (95% CI, 0.3%-1.3%; I2 = 66.4%). Cases with combined stigmata showed a significantly higher association with OSD than those with a single stigma (10.5% [95% CI, 6.9%-15.8%] vs 2.3% [%, 95% CI, 1.5%-3.5%]; P < .001). The pooled proportion of OSD cases among patients with an atypical dimple was significantly higher than among those with simple dimple (8.8% [95% CI, 4.5%-16.6%] vs 0.6% [95% CI of 1.4%-2.1%]; P = .001). Conclusions and Relevance: The proportion of OSD in healthy, asymptomatic patients with midline cutaneous stigmata was low, and the proportion of patients who underwent a neurosurgical intervention was even lower. However, a careful evaluation as well as potential spinal magnetic resonance imaging is recommended for neonates or infants with combined stigmata or an atypical dimple for possible high-risk lesions.

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.

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.

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.

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.

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.

Optimal use of CT imaging in pediatric congenital cholesteatoma.

OBJECTIVE: This study aimed to determine the radiation dose of temporal bone computed tomography (TBCT) to detect pediatric congenital cholesteatoma (CC), and suggests strategy for lowering perioperative radiation dose. METHODS: Fifty-three CC patients followed up for more than 12 months after surgery. Perioperative clinical findings and the effective radiation dose (ERD) of TBCT were investigated. Patients' mean age at initial TBCT was 60 months; the mean follow-up period was 43 months. RESULTS: In 33 (62.3%) of 53 patients, only one TBCT was performed postoperatively. Postoperative CT imaging was performed to evaluate before second-stage ossiculoplasty, due to suspicion of CC recurrence on examinations, or as part of follow-up. When TBCT was performed on more than two occasions after surgery as a part of follow-up, there was no difference in the distribution of stage or type of CC compared to patients subjected to TBCT on less than three occasions (p=0.093 and p=0.744, respectively). During the most-recent follow-up of these 53 cases, there was no CC recurrence. The mean ERD of a single TBCT was 1.2mSv, and the mean cumulative ERD of TBCT was 2mSv per patient. CONCLUSION: Mean and cumulative ERD of TBCT performed in CC cases was not too high to consider radiation hazard. However, efforts to minimize the number of CT scans should be taken basically.

Cranial Nerve Disorders in Children: MR Imaging Findings.

Cranial nerve disorders are uncommon disease conditions encountered in pediatric patients, and can be categorized as congenital, inflammatory, traumatic, or tumorous conditions that involve the cranial nerve itself or propagation of the disorder from adjacent organs. However, determination of the normal course, as well as abnormalities, of cranial nerves in pediatric patients is challenging because of the small caliber of the cranial nerve, as well as the small intracranial and skull base structures. With the help of recently developed magnetic resonance (MR) imaging techniques that provide higher spatial resolution and fast imaging techniques including three-dimensional MR images with or without the use of gadolinium contrast agent, radiologists can more easily diagnose disease conditions that involve the small cranial nerves, such as the oculomotor, abducens, facial, and hypoglossal nerves, as well as normal radiologic anatomy, even in very young children. If cranial nerve involvement is suspected, careful evaluation of the cranial nerves should include specific MR imaging protocols. Localization is an important consideration in cranial nerve imaging, and should cover entire pathways and target organs as much as possible. Therefore, radiologists should be familiar not only with the various diseases that cause cranial nerve dysfunction, and the entire course of each cranial nerve including the intra-axial nuclei and fibers, but also the technical considerations for optimal imaging of pediatric cranial nerves. In this article, we briefly review normal cranial nerve anatomy and imaging findings of various pediatric cranial nerve dysfunctions, as well as the technical considerations of pediatric cranial nerve imaging. Online supplemental material is available for this article. (©)RSNA, 2016.

Humidifier disinfectant-associated children's interstitial lung disease: Computed tomographic features, histopathologic correlation and comparison between survivors and non-survivors.

OBJECTIVES: To report radiologic findings with histopathologic correlations of humidifier disinfectant-associated children's interstitial lung disease (HD-chILD) and to compare computed tomography (CT) findings between survivors and non-survivors. METHODS: Forty-seven children with HD-chILD (27.4 ± 12.4 months old) were categorized as survivors (n = 25) and non-survivors (n = 22). The patterns, distributions, and chronological changes in lung lesions at follow-up CT were investigated. Histopathologic correlations were performed in 23 patients. RESULTS: CT features were characterized by chronological changes, from consolidation to centrilobular opacities, and lesions eventually became faint centrilobular nodules. Histopathologic features were bronchocentric-distributed fibro-inflammatory lesions, which were more profound in the advanced stage than the early stage. Consolidation ≥ 30 % [hazard ratio (HR), 2.932], centrilobular opacities ≥ 60 % of the total lung volume (TLV; HR, 0.206) and spontaneous air leaks (HR, 3.457) were significant factors associated with patient survival, as per univariate analysis. Consolidation ≥ 30 % (HR, 3.519), centrilobular opacities ≥ 60 % (HR, 0.205) and diffuse ground glass opacity (GGO) ≥ 70 % of the TLV (HR, 3.521) were significant factors associated with patient survival, as determined via multivariate analysis. CONCLUSION: Distinctive chronological CT features were observed in the HD-chILD images. Spontaneous air leaks, consolidation, GGO, and centrilobular opacities were prognostic factors. KEY POINTS: Chemical disinfectants can induce severe inhalation lung injury. Lung injury caused by inhaled disinfectants demonstrates chronologic changes in radiologic findings. Understanding of radiological characteristics is important to predict outcomes in chemical pneumonitis. Physicians should be aware of the potential risk of environmental chemicals.

Bronchopulmonary dysplasia: new high resolution computed tomography scoring system and correlation between the high resolution computed tomography score and clinical severity.

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

Imaging findings of angiomyxolipoma of the spermatic cord mimicking inguinal hernia.

We report the case in a 72-year-old man who presented with a right inguinal mass and with a one month history that was initially interpreted as an inguinal hernia. Ultrasonography (US) and computed tomography (CT) demonstrated a right inguinal mass, including myxoid and fat component, extending from the right spermatic cord to the right inguinal subcutaneous layer. Mass excision was performed, and the diagnosis turned out to be angiomyxolipoma. Angiomyxolipoma is a rare tumor and the preoperative diagnosis of this disease is very difficult. However, angiomyxolipoma of the spermatic cord should be considered in the differential diagnosis in patients with an irreducible inguinal mass. Imaging diagnosis, such as US and CT may help to make a preoperative diagnosis.

Ultrasound and MR findings in sclerosing perineurioma.

Perineurioma is an unusual benign peripheral nerve sheath tumor that includes intraneural, soft tissue (conventional), reticular and sclerosing types. Sclerosing perineurioma is a recently described distinctive variant occurring nearly exclusively on the hands of young adults, in which it presents as a small, painless, dermal or subcutaneous mass. The only report of imaging findings in sclerosing perineurioma was by Miyake et al., who described the MR findings in 2006. However, there have been no reports of the ultrasound features. We report a 22-year-old man with sclerosing perineurioma and describe the lesion's ultrasound and MR features.