Magnetic resonance imaging of Müllerian anomalies in girls: concepts and controversies.

Female Müllerian anomalies are the result of failure of formation, fusion or resorption of the Müllerian ducts and are relatively common, with a prevalence of 5.5-7.0% in the general population. While some of these anomalies are asymptomatic, those presenting with obstruction require accurate identification for optimal clinical management including potential surgical treatment. MRI is a useful adjunct to sonography in the evaluation of Müllerian anomalies, typically allowing a more complete characterization of the malformation. Technical aspects, embryologic concepts and controversies regarding classification systems are highlighted in this review. Several Müllerian anomalies are discussed and illustrated in more detail utilizing various cases with pelvic MRI studies.

Diagnostic Performance of LI-RADS Version 2018 for Evaluation of Pediatric Hepatocellular Carcinoma.

Background The Liver Imaging Reporting and Data System (LI-RADS) has standardized the evaluation of adult but not pediatric hepatocellular carcinoma (HCC). Purpose To evaluate the performance of LI-RADS version 2018 for diagnosis of pediatric HCC. Materials and Methods This multi-institution retrospective study evaluated all available dynamic CT and/or MRI scans of pediatric (≤18 years) HCC from five institutions between July 2009 and April 2019. The control group included an equal number of other enhancing hepatic lesions. Blinded to final diagnosis, three radiologists independently applied LI-RADS version 2018 criteria. The reference standard was pathologic examination or more than 1 year follow-up. Sensitivity and specificity of LI-RADS were computed using a dichotomous classification of LR-1, LR-2, or LR-3 versus LR-4, LR-5, LR-TIV (tumor in vein), or LR-M (probably or definitely malignant but not HCC-specific) for predicting hepatic malignancy in the entire cohort and in patients at risk for HCC. Results The cohort consisted of 116 children: 58 with HCC (mean age, 12 years ± 5; 31 girls) and 58 with other enhancing hepatic masses (mean age, 12 years ± 5; 42 girls). Frequencies of major criteria in classic HCC for the three readers were as follows: nonrim arterial phase hyperenhancement, 49%-62% (19-24 of 39 patients); nonperipheral "washout," 36%-59% (14-23 of 39 patients); and enhancing "capsule," 28%-38% (11-15 of 39 patients). For the full cohort, the sensitivity of LR-4, LR-5, LR-TIV, or LR-M for malignancy among the three readers ranged from 85% (95% CI: 76, 94) to 88% (95% CI: 80, 96); specificity of LR-1, LR-2, or LR-3 for benignity ranged from 54% (95% CI: 40, 68) to 70% (95% CI: 57, 83). In the at-risk subgroup, sensitivity ranged from 58% (95% CI: 36, 80) to 68% (95% CI: 48, 89); specificity ranged from 56% (95% CI: 37, 74) to 63% (95% CI: 45, 81). All lesions categorized as LR-TIV (n = 10-13) were HCCs. Conclusion Liver Imaging Reporting and Data System version 2018 had moderate sensitivity but low specificity for the diagnosis of pediatric hepatocellular carcinoma (HCC), which had low frequencies of the major criteria used for adult HCC diagnosis. © RSNA, 2021 See also the editorial by Paltiel in this issue.

Pediatric Hepatoblastoma, Hepatocellular Carcinoma, and Other Hepatic Neoplasms: Consensus Imaging Recommendations from American College of Radiology Pediatric Liver Reporting and Data System (LI-RADS) Working Group.

Appropriate imaging is imperative in evaluating children with a primary hepatic malignancy such as hepatoblastoma or hepatocellular carcinoma. For use in the adult patient population, the American College of Radiology created the Liver Imaging Reporting and Data System (LI-RADS) to provide consistent terminology and to improve imaging interpretation. At present, no similar consensus exists to guide imaging and interpretation of pediatric patients at risk for developing a liver neoplasm or how best to evaluate a pediatric patient with a known liver neoplasm. Therefore, a new Pediatric Working Group within American College of Radiology LI-RADS was created to provide consensus for imaging recommendations and interpretation of pediatric liver neoplasms. The article was drafted based on the most up-to-date existing information as interpreted by imaging experts comprising the Pediatric LI-RADS Working Group. Guidance is provided regarding appropriate imaging modalities and protocols, as well as imaging interpretation and reporting, with the goals to improve imaging quality, to decrease image interpretation errors, to enhance communication with referrers, and to advance patient care. An expanded version of this document that includes broader background information on pediatric hepatocellular carcinoma and rationale for recommendations can be found in Appendix E1 (online).

Optimization of Pediatric Body CT Angiography: What Radiologists Need to Know.

OBJECTIVE. Pediatric CT angiography (CTA) presents unique challenges compared with adult CTA. Because of the ionizing radiation exposure, CTA should be used judiciously in children. The pearls offered here are observations gleaned from the authors' experience in the use of pediatric CTA. We also present some potential follies to be avoided. CONCLUSION. Understanding the underlying principles and paying meticulous attention to detail can substantially optimize dose and improve the diagnostic quality of pediatric CTA.

Applications of Pediatric Body CT Angiography: What Radiologists Need to Know.

OBJECTIVE. Pediatric CT angiography (CTA) can be useful for assessing numerous congenital and acquired disorders. This article discusses common pediatric applications of thoracoabdominal CTA, including for congenital pulmonary airway malformation, sequestration, vascular rings, aortic coarctation, pulmonary embolism, nontraumatic hemorrhage, abdominal transplant evaluation, and several vascular disorders, and highlights key clinical and imaging features. CONCLUSION. With appropriate use, CTA can play a fundamental role in diagnostic and preprocedural assessment in a variety of pediatric conditions.

Gadolinium-based contrast agents in children.

Gadolinium-based contrast agents (GBCAs) are widely used in medical imaging, with greater than 300 million doses administered since their introduction. The risk of adverse reactions is very low, and GBCAs were thought to be very safe until the discovery of nephrogenic systemic fibrosis (NSF). Since that time, gadolinium has been found to deposit throughout the body, including the brain, where it is visible on non-contrast T1-weighted MR images in people with normal renal function. The clinical effects of this deposition remain unknown and may not exist. In this review the authors provide a comprehensive update on GBCAs and their potential risks, within a historical context and through the lens of a pediatric radiologist.

Fractures in children with newly diagnosed hepatoblastoma.

BACKGROUND: Hepatoblastoma is the most common primary hepatic malignancy in children. We have recently noticed an increased incidence of unsuspected fractures in children with newly diagnosed hepatoblastoma. This association has been suggested in the past, but the incidence and pathophysiology remain uncertain. OBJECTIVE: To define the incidence and imaging features of fractures in children with newly diagnosed hepatoblastoma. MATERIALS AND METHODS: We searched the oncology database and the radiology picture archiving and communication system of our large tertiary care children's hospital between January 2000 and August 2013 for all patients who presented to our institution with newly diagnosed hepatoblastoma. We reviewed all available imaging exams (radiographs, CT scans, MRIs, and nuclear medicine studies) to identify children who had radiologically apparent fractures on exams during the 50 days prior to diagnosis or up to 2 weeks after the date of hepatoblastoma diagnosis. RESULTS: Forty-five children were included in this retrospective study. Eight children (17.8%) had fractures within 50 days prior to diagnosis or up to 2 weeks after the date of diagnosis, with a mean number of 4.9 fractures per patient (range 1-13). Only 21 of the 39 fractures (54%) were diagnosed during the initial image interpretation. Fractures most commonly occurred in the ribs (n=21) and vertebral bodies (n=10). The presence of a fracture was not associated with an identified demographic, tumor or laboratory finding. CONCLUSION: Unsuspected fractures are relatively common in children with newly diagnosed hepatoblastoma.

Peer Feedback, Learning, and Improvement: Answering the Call of the Institute of Medicine Report on Diagnostic Error.

In September 2015, the Institute of Medicine (IOM) published a report titled "Improving Diagnosis in Health Care," in which it was recommended that "health care organizations should adopt policies and practices that promote a nonpunitive culture that values open discussion and feedback on diagnostic performance." It may seem counterintuitive that a report addressing a highly technical skill such as medical diagnosis would be focused on organizational culture. The wisdom becomes clearer, however, when examined in the light of recent advances in the understanding of human error and individual and organizational performance. The current dominant model for radiologist performance improvement is scoring-based peer review, which reflects a traditional quality assurance approach, derived from manufacturing in the mid-1900s. Far from achieving the goals of the IOM, which are celebrating success, recognizing mistakes as an opportunity to learn, and fostering openness and trust, we have found that scoring-based peer review tends to drive radiologists inward, against each other, and against practice leaders. Modern approaches to quality improvement focus on using and enhancing interpersonal professional relationships to achieve and maintain high levels of individual and organizational performance. In this article, the authors review the recommendations set forth by the recent IOM report, discuss the science and theory that underlie several of those recommendations, and assess how well they fit with the current dominant approach to radiology peer review. The authors also offer an alternative approach to peer review: peer feedback, learning, and improvement (or more succinctly, "peer learning"), which they believe is better aligned with the principles promoted by the IOM. © RSNA, 2016.

Pediatric Chest CT Diagnostic Reference Ranges: Development and Application.

Purpose To determine diagnostic reference ranges on the basis of the size of a pediatric patient's chest and to develop a method to estimate computed tomographic (CT) scanner-specific mean size-specific dose estimates (SSDEs) as a function of patient size and the radiation output of each CT scanner at a site. Materials and Methods The institutional review boards of each center approved this retrospective, HIPAA-compliant, multicenter study; informed consent was waived. CT dose indexes (SSDE, volume CT dose index, and dose length product) of 518 pediatric patients (mean age, 9.6 years; male patients, 277 [53%]) who underwent CT between July 1, 2012, and June 30, 2013, according to the guidelines of the Quality Improvement Registry in CT Scans in Children were retrieved from a national dose data registry. Diagnostic reference ranges were developed after analysis of image quality of a subset of 111 CT examinations to validate image quality at the lower bound. Pediatric dose reduction factors were calculated on the basis of SSDEs for pediatric patients divided by SSDEs for adult patients. Results Diagnostic reference ranges (SSDEs) were 1.8-3.9, 2.2-4.5, 2.7-5.1, 3.6-6.6, and 5.5-8.4 mGy for effective diameter ranges of less than 15 cm, 15-19 cm, 20-24 cm, 25-29 cm, and greater than or equal to 30 cm, respectively. The fractions of adult doses (pediatric dose reduction factors) used within the consortium for patients with lateral dimensions of 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, and 38 cm were 0.29, 0.33, 0.38, 0.44, 0.50, 0.58, 0.66, 0.76, 0.87, 1.0, and 1.15, respectively. Conclusion Diagnostic reference ranges developed in this study provided target ranges of pediatric dose indexes on the basis of patient size, while the pediatric dose reduction factors of this study allow calculation of unique reference dose indexes on the basis of patient size for each of a site's CT scanners. © RSNA, 2017 Online supplemental material is available for this article.

Non-Catheter-related Venous Thromboembolism in Children: Imaging Review from Head to Toe.

Non-catheter-related venous thromboembolism (VTE) is less common in children than in adults. Although the presence of a central venous catheter is the most common cause of venous thrombosis in children, infection and inflammation, malignancy, hypercoagulability, dehydration, and certain sites of normal variant and pathologic anatomic narrowing all predispose to VTE in children. The mortality and morbidity of VTE vary according to the underlying cause, including whether malignancy is present. Various modalities including ultrasonography (US), computed tomography, and magnetic resonance imaging can be used to image VTE, with some modalities better suited to particular parts of the body and clinical scenarios than others. When feasible, US is the initial test of choice for the diagnosis of VTE. US findings of acute VTE include a dilated noncompressible vein, intraluminal echoes, lack of color flow, and abnormal spectral venous waveforms. Serial US examinations are useful for monitoring patient response to therapy; a normal compressible vein will be seen after complete resolution of thrombus, and chronic venous changes including wall thickening, intraluminal webs, and phleboliths, which are readily apparent at US. Accurate and timely diagnosis of VTE must take into account the various advantages and disadvantages of each modality including speed, accuracy, availability, exposure to ionizing radiation, and need for sedation, as well as the clinical stability and transportability of the child. This article reviews some of the more common causes of VTE in children (other than those related to a central venous catheter) according to body part and discusses the associated imaging findings. ©RSNA, 2017.

Sonographic Evaluation of Pediatric Thyroid Nodules.

A thyroid nodule detected clinically or incidentally at medical imaging is a common indication for ultrasonography (US) in the adult population. This scenario is less frequently the case in pediatric patients, and the approach to evaluation of thyroid nodules deserves modification in these patients because of the increased probability of malignancy in children, compared with adults. Evaluating a thyroid nodule with US in a systematic way requires familiarity with a number of features that can be assessed and the terms that the radiologist uses in each category. The probability of malignancy is influenced by certain features, and several models have emerged to integrate these details into an overall risk assessment to guide management and biopsy of thyroid nodules. Clinical features of thyroid cancer differ between pediatric and adult patients, and risk factors and certain genetic syndromes portend earlier manifestation of thyroid malignancy. This article provides a review of (a) US features of thyroid nodules with an emphasis on the predictive capacity for malignancy, focused on the pediatric age group when the data exist, (b) clinical information, including risk factors and genetic syndromes pertinent to the pediatric population, and (c) the state of the current literature and controversies in diagnosing and managing pediatric thyroid cancer. ©RSNA, 2017.

Pediatric chest ultrasound: a practical approach.

Chest ultrasonography is an important imaging adjunct for diagnosing and managing disease in children. Compared with CT and MRI, ultrasound is cheaper, portable and provides vascular or flow-related information that cannot otherwise be obtained noninvasively. The spatial and temporal resolution of ultrasound is excellent, particularly for superficial structures. In cases where a suspicious abnormality is found, tissue sampling can be performed percutaneously with US guidance. Ultrasound also excels at demonstrating and characterizing pleural fluid collections. As concerns about radiation exposure increase among laypersons and doctors alike, there is a compelling argument for making ultrasonography the initial imaging study of choice for many thoracic abnormalities in a child. In this review the authors discuss and illustrate the US findings of some of the more common chest complaints in children.

Quality measures and pediatric radiology: suggestions for the transition to value-based payment.

Recent political and economic factors have contributed to a meaningful change in the way that quality in health care, and by extension value, are viewed. While quality is often evaluated on the basis of subjective criteria, pay-for-performance programs that link reimbursement to various measures of quality require use of objective and quantifiable measures. This evolution to value-based payment was accelerated by the 2015 passage of the Medicare Access and CHIP (Children's Health Insurance Program) Reauthorization Act (MACRA). While many of the drivers of these changes are rooted in federal policy and programs such as Medicare and aimed at adult patients, the practice of pediatrics and pediatric radiology will be increasingly impacted. This article addresses issues related to the use of quantitative measures to evaluate the quality of services provided by the pediatric radiology department or sub-specialty section, particularly as seen from the viewpoint of a payer that may be considering ways to link payment to performance. The paper concludes by suggesting a metric categorization strategy to frame future work on the subject.

Prospective Assessment of Correlation between US Acoustic Radiation Force Impulse and MR Elastography in a Pediatric Population: Dispersion of US Shear-Wave Speed Measurement Matters.

Purpose To evaluate the correlation between ultrasonographic (US) point shear-wave elastography (SWE) and magnetic resonance (MR) elastography liver shear-wave speed (SWS) measurements in a pediatric population and to determine if US data dispersion affects this relationship. Materials and Methods Institutional review board approval was obtained for this HIPAA-compliant investigation; informed consent and patient assent (as indicated) were obtained. Patients (age range, 0-21 years) undergoing clinical liver MR elastography between July 2014 and November 2015 were prospectively enrolled. Patients underwent two-dimensional gradient-recalled-echo 1.5-T MR elastography with point SWE performed immediately before or immediately after MR elastography. Spearman rank correlation coefficients were calculated to assess the relationship and agreement between point SWE and MR elastography SWS measurements. Uni- and multivariate logistic regression were performed to identify predictors of US data dispersion, with the best multivariate model selected based on Akaike information criterion. Results A total of 55 patients (24 female) were enrolled (mean age, 14.0 years ± 3.9 (standard deviation) (range, 3.5-21.4 years). There was fair correlation between point SWE and MR elastography SWS values for all patients (ρ = 0.33, P = .016). Correlation was substantial, however, when including only patients with minimal US data dispersion (n = 26, ρ = 0.61, P = .001). Mean body mass index (BMI) was significantly lower in patients with minimal US data dispersion than in those with substantial US data dispersion (25.4 kg/m2 ± 7.8 vs 32.3 kg/m2 ± 8.3, P = .003). At univariate analysis, BMI (odds ratio, 1.12; 95% confidence interval [CI]: 1.03, 1.21; P = .006) and abdominal wall thickness (odds ratio, 2.50; 95% CI: 1.32, 4.74; P = .005) were significant predictors of US data dispersion. In the best multivariate model, BMI was the only significant predictor (odds ratio, 1.11; 95% CI: 1.03, 1.20; P = .009). Conclusion Point SWE and MR elastography liver SWS measurements correlate well in patients with a BMI of less than 30 kg/m2 and minimal US data dispersion; increasing US data dispersion is directly related to a higher BMI. © RSNA, 2016.

A prognostic tool to predict severe acute pancreatitis in pediatrics.

BACKGROUND/OBJECTIVES: Approximately 15-20% of pediatric patients with acute pancreatitis (AP) develop severe disease. Severity scoring tools were developed for adult patients, but have limitations when applied in children. We aimed to identify early predictors of severe acute pancreatitis (SAP) on hospital admission for early risk stratification of patients. METHODS: Retrospective review of AP admissions was conducted. The derivation cohort included cases at Cincinnati Children's Hospital Medical Center (CCHMC) between 2009 and 2013. Clinical data collected during the first 24 h of admission were analyzed and a predictive model was derived through statistical analysis. The performance of the model was evaluated in a validation cohort from 2 more institutions other than CCHMC. RESULTS: In the derivation cohort 19% of the 284 admissions were SAP. A generalized linear mixed effect model analysis revealed that lipase, albumin and white blood count (WBC) play a role in the development of SAP (area under the receiver operating curve (AUROC 0.76)). In the validation cohort of 165 AP cases, SAP ranged from 8 to 20% at the three institutions. Performance of the model in this cohort was comparable to the derivation model (AUROC 0.77). There were 369 encounters in the combined derivation and validation pool (AUROC 0.76). CONCLUSIONS: The prognostic severity tool with 3 variables (lipase, albumin, and WBC) obtained within 24 h of admission can be applied to predict SAP in pediatric patients.

Magnetic resonance imaging of acquired disorders of the pediatric female pelvis other than neoplasm.

Transabdominal US remains the primary screening imaging modality of the pediatric female pelvis. However, MRI has become an invaluable adjunct to US in recent years. MRI offers superb soft-tissue contrast resolution that allows for detailed evaluation, particularly of the ovaries and their associated pathology. MRI can yield diagnostic information that is similar to or even better than that of US, especially in nonsexually active girls in whom transvaginal US would be contraindicated. MRI is generally a second-line examination and is preferred over CT because it does not involve the use of ionizing radiation. MRI might be underutilized in this population, particularly in differentiating surgical from nonsurgical conditions. This article reviews the relevant anatomy and discusses imaging of acquired conditions that involve the pediatric female genital tract, illustrating associated pathology with case examples.

Diagnostic Performance and Dose Comparison of Filtered Back Projection and Adaptive Iterative Dose Reduction Three-dimensional CT Enterography in Children and Young Adults.

PURPOSE: To investigate diagnostic performance and radiation dose with the use of computed tomographic (CT) enterography in children and young adults and to compare reconstruction with filtered back projection (FBP) to that with adaptive iterative dose reduction (AIDR) with three-dimensional (3D) processing. MATERIALS AND METHODS: This retrospective investigation was HIPAA compliant and approved by the institutional review board. Informed consent was waived. CT enterographic examinations performed between October 2008 and June 2009 with FBP and between August 2012 and April 2014 with AIDR 3D in patients who had received histologic evaluation within 45 days of imaging were included. Two reviewers retrospectively and independently evaluated the studies for findings of active inflammation, and diagnostic performance and interreader reliability were assessed. The reference standard was histologic findings. Objective and subjective image quality also was assessed. The size-specific dose estimate was compared between the two groups. Two-sample t tests or analysis of variance tests were performed to assess for differences in diagnostic accuracy, image quality, and radiation dose between the FBP and AIDR 3D examinations. RESULTS: Fifty patients were included in the FBP group (mean age, 14.1 years; range, 8-21 years) and 68 patients were in the AIDR 3D group (mean age, 13.2 years; range, 2-29 years). Sensitivity and specificity for detection of active inflammation were 96% (26 of 27) and 96% (22 of 23), respectively, for the FBP group and 90% (45 of 50) and 89% (16 of 18), respectively, for the AIDR 3D group. Dichotomous interreader reliability (κ) for the entire group was 0.86. The mean size-specific dose estimate for all weights was significantly lower for the AIDR 3D group (6.1 mGy ± 2.1) than that for the FBP group (16.7 mGy ± 5.2; P < .0001). No significant difference was found in objective image noise for soft-tissue structures (P = .2-.8). CONCLUSION: CT enterography is highly accurate for detection of active inflammation in pediatric patients and has excellent interreader reliability. Reduced-dose CT enterography with AIDR 3D allowed substantial dose reduction compared with that used with FBP CT enterographic examinations, while maintaining a high diagnostic performance.

Toward Large-Scale Process Control to Enable Consistent CT Radiation Dose Optimization.

OBJECTIVE: This article reviews the concepts of CT radiation dose optimization and process control, discusses how to achieve optimization and how to verify that it is consistently accomplished, and proposes strategies to move toward large-scale application. CONCLUSION: CT dose optimization is achieved when the least amount of radiation necessary is used to achieve adequate image quality. The key to consistent optimization is minimization of unnecessary variation. This minimization is accomplished through local process control mechanisms.

Cross-vendor validation of liver magnetic resonance elastography.

PURPOSE: To evaluate and validate the reproducibility of MR Elastography (MRE)-derived liver stiffness values on two different MR vendor platforms performed on the same subject on the same day. METHODS: This investigation was approved by the hospital IRB. MRE exams were performed twice in identical fashion in eight volunteers and in five clinical patients on two different 1.5 T MR scanners-once on a Philips MR scanner and immediately afterward in back-to-back fashion on a General Electric MR scanner, or vice versa. All scan parameters were kept identical on the two platforms to the best extent possible. After the MRE magnitude and phase images were obtained, the data were converted into quantitative images displaying the stiffness of the liver parenchyma. Mean liver stiffness values between the two platforms were compared using interclass correlation with a p value <0.05 considered statistically significant. RESULTS: Interclass correlation coefficient (ICC) value of 0.994 was obtained for 13 subjects with p value <0.001 indicating a significantly positive correlation. CONCLUSION: As MRE gains in acceptance and as its availability becomes more widespread, it is important to ascertain and confirm that liver stiffness values obtained on different MRE vendor platforms are consistent and reproducible. In this small pilot investigation, we demonstrate that liver stiffness measurement with MRE is reproducible and has very good consistency across two vendor platforms.