Near-pair patch generative adversarial network for data augmentation of focal pathology object detection models.

Purpose: The limited volume of medical training data remains one of the leading challenges for machine learning for diagnostic applications. Object detectors that identify and localize pathologies require training with a large volume of labeled images, which are often expensive and time-consuming to curate. To reduce this challenge, we present a method to support distant supervision of object detectors through generation of synthetic pathology-present labeled images. Approach: Our method employs the previously proposed cyclic generative adversarial network (cycleGAN) with two key innovations: (1) use of "near-pair" pathology-present regions and pathology-absent regions from similar locations in the same subject for training and (2) the addition of a realism metric (Fréchet inception distance) to the generator loss term. We trained and tested this method with 2800 fracture-present and 2800 fracture-absent image patches from 704 unique pediatric chest radiographs. The trained model was then used to generate synthetic pathology-present images with exact knowledge of location (labels) of the pathology. These synthetic images provided an augmented training set for an object detector. Results: In an observer study, four pediatric radiologists used a five-point Likert scale indicating the likelihood of a real fracture (1 = definitely not a fracture and 5 = definitely a fracture) to grade a set of real fracture-absent, real fracture-present, and synthetic fracture-present images. The real fracture-absent images scored 1.7±1.0, real fracture-present images 4.1±1.2, and synthetic fracture-present images 2.5±1.2. An object detector model (YOLOv5) trained on a mix of 500 real and 500 synthetic radiographs performed with a recall of 0.57±0.05 and an F2 score of 0.59±0.05. In comparison, when trained on only 500 real radiographs, the recall and F2 score were 0.49±0.06 and 0.53±0.06, respectively. Conclusions: Our proposed method generates visually realistic pathology and that provided improved object detector performance for the task of rib fracture detection.

High sensitivity methods for automated rib fracture detection in pediatric radiographs.

Rib fractures are highly predictive of non-accidental trauma in children under 3 years old. Rib fracture detection in pediatric radiographs is challenging because fractures can be obliquely oriented to the imaging detector, obfuscated by other structures, incomplete, and non-displaced. Prior studies have shown up to two-thirds of rib fractures may be missed during initial interpretation. In this paper, we implemented methods for improving the sensitivity (i.e. recall) performance for detecting and localizing rib fractures in pediatric chest radiographs to help augment performance of radiology interpretation. These methods adapted two convolutional neural network (CNN) architectures, RetinaNet and YOLOv5, and our previously proposed decision scheme, "avalanche decision", that dynamically reduces the acceptance threshold for proposed regions in each image. Additionally, we present contributions of using multiple image pre-processing and model ensembling techniques. Using a custom dataset of 1109 pediatric chest radiographs manually labeled by seven pediatric radiologists, we performed 10-fold cross-validation and reported detection performance using several metrics, including F2 score which summarizes precision and recall for high-sensitivity tasks. Our best performing model used three ensembled YOLOv5 models with varied input processing and an avalanche decision scheme, achieving an F2 score of 0.725 ± 0.012. Expert inter-reader performance yielded an F2 score of 0.732. Results demonstrate that our combination of sensitivity-driving methods provides object detector performance approaching the capabilities of expert human readers, suggesting that these methods may provide a viable approach to identify all rib fractures.

Frequency of technical success of ultrasound-guided arthrogram injections in children.

BACKGROUND: MR arthrography is an essential diagnostic tool to assess and guide management of labral, ligamentous, fibrocartilaginous, and capsular abnormalities in children. While fluoroscopy is traditionally used for intra-articular contrast administration, ultrasound offers advantages of portability and lack of ionizing radiation exposure for both the patient and proceduralist. OBJECTIVE: The purpose of this retrospective study is to quantify technical success and frequency of complications of ultrasound-guided arthrogram injections at our institution. MATERIALS AND METHODS: This retrospective analysis investigates the results of 217 ultrasound-guided arthrograms of the shoulder, elbow, and hip in patients aged 5-18 years. Successful injection of contrast into the target joint, clinical indication for MR arthrography, and complications were reviewed. RESULTS: Accurate ultrasound-guided intra-articular administration of contrast into the target joint was successful for 100% of shoulder cases (90/90), 97% of elbow cases (77/79), and 98% of hip cases (47/48). Leak of contrast outside the target joint occurred in 1.4% (3/217) of cases. No major side effects including excessive bleeding, paresthesia, allergic reactions, or infection occurred during or after the procedure. Additionally, no major vessel, nerve, or tendon complications were observed on MR images. CONCLUSION: Ultrasound guidance is a reliable, effective, and safe approach to arthrography in children.

Short Falls in Childhood Occasionally Cause Major Brain Injuries Because of Unusual Circumstances.

METHODS: Records and imaging were reviewed for children younger than 6 years, hospitalized between 2015 and 2020 for major closed head injuries following less than 4-ft falls. Major injury was defined as intensive care admission more than 2 days, neurosurgical intervention, death, or disability at hospital discharge. Subjects were identified through Seattle and Spokane, Washington abuse consultations. Harborview Medical Center's trauma registry and Seattle Children's Hospital's Hemophilia Treatment Program and Radiology were searched for subjects. RESULTS: We identified 12 young children who sustained major closed head injury due to short falls. Seven developed major space-occupying epidural hemorrhages. One child developed internal hydrocephalus after intraventricular hemorrhage. One child with prior meningomyelocele, Chiari 2 malformation, and ventriculoperitoneal shunt developed shunt decompensation after an acute-on-chronic subdural hemorrhage. One child developed an internal capsule stroke because of a previously undiagnosed calcifying angiopathy. Another child developed space-occupying subdural hemorrhage associated with previously unrecognized platelet pool disorder. Only this child had abuse concerns, which were resolved with his coagulopathy diagnosis. One child had a diastatic skull fracture leading to pseudomeningocele.At Harborview Medical Center, 140 children were seen for short falls in the emergency department or inpatient service. Among the 40 needing intensive care, 4 (12.5%) had major injuries after short falls. Our hemophilia treatment program did not see any children who had sustained major injury following a short fall in a 5½ year period. CONCLUSIONS: Although young children rarely sustain major head injury following short falls, serious head injuries do occasionally occur because of unusual injury mechanisms or preexisting conditions. It is important to fully evaluate these patients to differentiate these unintentional falls from abusive head injury.

Tracheal Mirror Image Artifact in Patients With Normal and Pathologic Tracheas.

Ultrasonography is gaining popularity as a diagnostic imaging modality for airway pathology. Tracheal ultrasound (US) has several nuances that are important for clinicians, including imaging artifacts, which can be mistaken for pathology. Tracheal mirror image artifacts (TMIAs) occur when the US beam is reflected back to the transducer in a nonliner direction or with multiple timesteps. It has previously been believed that the convexity of the tracheal cartilage prevents mirror image artifacts, but in reality, the air column acts as an acoustic mirror and causes TMIA. We describe a cohort of patients with both normal and pathologic tracheas, all of whom have TMIA on the tracheal US. These artifacts are important to recognize, especially as the airway US becomes more commonplace.

Symptomatic Cervical Spinal Cord Injury Without Accompanying Intracranial Injury Because of Child Abuse.

ABSTRACT: Although spinal ligamentous injuries and extra-axial hemorrhages are known to commonly accompany abusive head trauma (AHT), symptomatic and radiological apparent cervical spinal cord injuries are rare. Of the 16 previously reported cases, 3 such cord injuries lacked the accompanying intracranial injuries of AHT. We report an additional child who developed symptomatic central cervical cord syndrome, with accompanying cervical imaging findings, but no intracranial AHT injuries. The mechanism of trauma for this child and the other children without intracranial injury remains unclear. However, 1 additional reported child sustained similar injuries when she was held by her head and shaken. It is likely that as cervical magnetic resonance imaging becomes more common in AHT, more cases will be recognized.

The undulating line sign and other more common pediatric central catheter malpositions.

Central venous and arterial catheters are among the most commonly assessed support devices by radiologists. The position of these catheters must be carefully assessed to ensure proper placement, as malpositioning may lead to life-threatening consequences. Therefore, it is important for radiologists to understand the anatomy of the central vessels and the expected location of catheters. While this can be difficult in small children and especially in neonates, knowledge of the expected course and ideal termination of catheters allows for recognition of a malpositioned line, which may be unsuspected clinically. The purpose of this article is to discuss appropriate positioning of central catheters in pediatric patients, focusing primarily on venous catheters. We also propose a new radiographic sign to recognize, the undulating line sign, as an indication of an inappropriate course of a newly placed venous catheter.

Palpable pediatric chest wall masses.

Pediatric chest wall lesions are varied in etiology ranging from normal and benign to aggressive and malignant. When palpable, these lesions can alarm parents and clinicians alike. However, most palpable pediatric chest lesions are benign. Familiarity with the various entities, their incidences, and how to evaluate them with imaging is important for clinicians and radiologists. Here we review the most relevant palpable pediatric chest entities, their expected appearance and the specific clinical issues to aid in diagnosis and appropriate treatment.

Extra-axial haemorrhages in young children with skull fractures: abuse or accident?

OBJECTIVE: Infant and toddler subdural haemorrhages (SDH) are often considered indicative of abuse or major trauma. However, accidental impact events, such as falls, cause contact extra-axial haemorrhages (EAHs). The current study sought to determine frequency and clinical behaviour of EAHs with infant and toddler accidental and abusive skull fractures. PATIENTS AND METHODS: Children aged <4 years with accidental skull fractures and abusive fractures identified by CT at two paediatric tertiary care centres. Clinical data were abstracted by child abuse paediatricians and images were reviewed by paediatric radiologists. Data were analysed using univariate and multivariate logistic regression as well as descriptive statistics. RESULTS: Among 227 subjects, 86 (37.9%) had EAHs. EAH was present in 73 (34.8%) accidental and 13 (76.5%) of the abusive injuries. Intracranial haemorrhage rates were not different for children with major or minor accidents but were fewer than abused. EAH was equally common with falls <4 and >4 ft. EAH depths did not differ by mechanism, but 69% of accidental EAHs were localised solely at fracture sites vs 38% abuse. Widespread and multifocal EAHs were more common with abuse. Children with abuse or major accidental injuries presented with lower initial Glasgow Coma Scales than those with minor accidents. Abused children had initial loss of consciousness more often than those with either minor or major accidents. CONCLUSIONS: Simple contact EAHs were common among children with minor and major accidental skull fractures. Accidental EAHs were more localised with less neurological dysfunction than abusive.

Pearls and Pitfalls of Thoracic Manifestations of Abuse in Children.

Child abuse is a broad term that includes, but is not limited to, physical or emotional harm, neglect, sexual abuse, and exploitation. In 2018 in the United States, there were nearly 700,000 victims of such maltreatment, of which 1700 children died. The majority of deaths occur in infants and toddlers under 3 years of age. While clinical signs and symptoms may raise suspicion for inflicted injury, such as bruising in young infants, imaging often plays a central role in identifying and characterizing nonaccidental trauma. The purpose of this article is to discuss the array of inflicted traumatic injuries to the thorax in children. Rib fractures are among the most common and telling features of physical abuse, especially in infants. The locations of such fractures and differences in appearance while healing will be presented, along with potential mimics and pitfalls. Less typical fractures seen in abuse will also be reviewed, including those of the sternum, clavicle, spine, and scapula. Finally, uncommon injuries to the lungs, heart and esophagus will also be considered.

Improving the detection of ventricular shunt disruption using volume-rendered three-dimensional head computed tomography.

Hydrocephalus is the most common neurosurgical disorder in children, and cerebrospinal fluid (CSF) diversion with shunt placement is the most commonly performed pediatric neurosurgical procedure. CT is frequently used to evaluate children with suspected CSF shunt malfunction to assess change in ventricular size. Moreover, careful review of the CT images is important to confirm the integrity of the imaged portions of the shunt system. Subtle shunt disruptions can be missed on multiplanar two-dimensional (2-D) CT images, especially when the disruption lies in the plane of imaging. The use of volume-rendered CT images enables radiologists to view the extracranial shunt tubing within the field of view as a three-dimensional (3-D) object. This allows for a rapid and intuitive method of assessing the integrity of the extracranial shunt tubing. The purpose of this pictorial essay is to discuss how volume-rendered CT images can be generated to evaluate CSF shunts in the pediatric population and to provide several examples of their utility in diagnosing shunt disruption. We also address the potential pitfalls of this technique and ways to avoid them.

Are Complex Skull Fractures Indicative of Either Child Abuse or Major Trauma in the Era of 3-Dimensional Computed Tomography Imaging?

OBJECTIVE: The aim of the study was to determine whether complex skull fractures are more indicative of child abuse or major trauma than simple skull fractures. DESIGN: This is a retrospective chart and imaging review of children diagnosed with a skull fracture. Subjects were from 2 pediatric tertiary care centers. Children younger than 4 years who underwent a head computed tomography with 3-dimensional rendering were included. We reviewed the medical records and imaging for type of skull fracture, abuse findings, and reported mechanism of injury. A complex skull fracture was defined as multiple fractures of a single skull bone, fractures of more than 1 skull bone, a nonlinear fracture, or diastasis of greater than 3 mm. Abuse versus accident was determined at the time of the initial evaluation with child abuse physician team confirmation. RESULTS: From 2011 to 2012, 287 subjects were identified by International Classification of Diseases, Ninth Revision, code. The 147 subjects with a cranial vault fracture and available 3-dimensional computed tomography composed this study's subjects. The average age was 12.3 months. Seventy four (50.3%) had complex and 73 (49.7%) had simple fractures. Abuse was determined in 6 subjects (4.1%), and a determination could not be made for 5 subjects. Adding abused children from 2013 to 2014 yielded 15 abused subjects. Twelve of the abused children (80%) had complex fractures; more than the 66 (48.5%) of 136 accidentally injured children (P = 0.001; relative risk = 1.65 [1.21-2.24]). However, among children with a complex fracture, the positive predictive value for abuse was only 7%. CONCLUSIONS: Complex skull fractures frequently occur from accidental injuries. This study suggests that the presence of complex skull fractures should not be used alone when making a determination of abuse.

The current and future roles of artificial intelligence in pediatric radiology.

Artificial intelligence (AI) is a broad and complicated concept that has begun to affect many areas of medicine, perhaps none so much as radiology. While pediatric radiology has been less affected than other radiology subspecialties, there are some well-developed and some nascent applications within the field. This review focuses on the use of AI within pediatric radiology for image interpretation, with descriptive summaries of the literature to date. We highlight common features that enable successful application of the technology, along with some of the limitations that can inhibit the development of this field. We present some ideas for further research in this area and challenges that must be overcome, with an understanding that technology often advances in unpredictable ways.

Accuracy and Reliability of 4D-CT and Flexible Laryngoscopy in Upper Airway Evaluation in Robin Sequence.

OBJECTIVES: To evaluate the performance of 4-dimensional computed tomography (4D-CT) in assessing upper airway obstruction (UAO) in patients with Robin sequence (RS) and compare the accuracy and reliability of 4D-CT and flexible fiber-optic laryngoscopy (FFL). STUDY DESIGN: Prospective survey of retrospective clinical data. SETTING: Single, tertiary care pediatric hospital. METHODS: At initial and 30-day time points, a multidisciplinary group of 11 clinicians who treat RS rated UAO severity in 32 sets of 4D-CT visualizations and FFL videos (dynamic modalities) and static CT images. Raters assessed UAO at the velopharynx and oropharynx (1 = none to 5 = complete) and noted confidence levels of each rating. Intraclass correlation and Krippendorff alpha were used to assess intra- and interrater reliability, respectively. Accuracy was assessed by comparing clinician ratings with quantitative percentage constriction (QPC) ratings, calculated based on 4D-CT airway cross-sectional area. Results were compared using Wilcoxon rank-sum and signed-rank tests. RESULTS: There was similar intrarater agreement (moderate to substantial) with 4D-CT and FFL, and both demonstrated fair interrater agreement. Both modalities underestimated UAO severity, although 4D-CT ratings were significantly more accurate, as determined by QPC similarity, than FFL (-1.06 and -1.46 vs QPC ratings, P = .004). Overall confidence levels were similar for 4D-CT and FFL, but other specialists were significantly less confident in FFL ratings than were otolaryngologists (2.25 and 3.92, P < .0001). CONCLUSION: Although 4D-CT may be more accurate in assessing the degree of UAO in patients with RS, 4D-CT and FFL assessments demonstrate similar reliability. Additionally, 4D-CT may be interpreted with greater confidence by nonotolaryngologists who care for these patients.

Uniquely pediatric upper extremity injuries.

The pediatric population is prone to unique upper extremity injuries that are not typically seen in adults. The normal dynamic maturation pattern of ossification centers and open physis can potentially confuse radiologists who are not familiar with the pediatric patients. In this review article, we discuss the normal anatomy and commonly encountered acute and chronic upper extremity injuries such as supracondylar distal humeral fracture and osteochondritis dissecans, in pediatric patients. Diagnosing the correct type of fracture (e.g., buckle vs Salter-Harris) is important for proper management of the injury. With an increasing number of adolescents participating in competitive sports, specific sports related injuries such as little league shoulder, gymnast wrist, and medial epicondyle apophysitis, are also discussed in this review. We examine late complications of injuries, such as physeal bar formation and fishtail deformity of the distal humerus.

Pediatric radiologic manifestations of COVID-19.

PURPOSE: While full description of pediatric COVID-19 manifestations is evolving, children appear to present less frequently, and often display a less severe disease phenotype. There is correspondingly less data regarding pediatric radiologic findings. To describe the imaging findings of pediatric COVID-19, we evaluated the radiologic imaging of the initial patient cohort identified at our institution. METHODS: In this IRB approved study, all patients at our institution aged 0-21 with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) based on PCR or immunoglobulin testing were identified. Imaging was reviewed by the co-authors and presence of abnormalities determined by consensus. Pre-existing comorbidities and alternative diagnoses were recorded. Rates of each finding were calculated. Findings were compared to published data following review of the available literature. RESULTS: Out of 130 Covid-19 positive patients, 24 patients underwent imaging, including 21 chest radiographs and 4 chest CT scans. Chest x-rays were normal in 33%. Patchy or streaky opacities were the most common radiographic abnormality, each seen in 38% of patients. CT findings included ill-defined or geographic ground glass opacities, dense opacities, septal thickening and crazy paving, and small pleural effusions. Results are similar to those reported in adults. Multiple COVID-19 positive children presented for symptoms due to an additional acute illness, including appendicitis and urinary infection. CONCLUSIONS: Radiologic findings of COVID-19 in pediatric patients range from normal to severe ARDS type appearance. During this ongoing pandemic, these radiographic signs can be useful for the evaluation of disease status and guiding care, particularly in those with comorbidities. PRECIS: Radiologic findings of COVID-19 in pediatric patients are similar to those seen in adults, and may range from normal to severe ARDS type appearance.

4D Computed Tomography for Dynamic Upper Airway Evaluation in Robin Sequence.

Thorough assessment of dynamic upper airway obstruction (UAO) in Robin sequence (RS) is critical, but traditional evaluation modalities have significant limitations. Four-dimensional computed tomography (4D-CT) is promising in that it enables objective and quantitative evaluation throughout all phases of respiration. However, there exist few protocols or analysis tools to assist in obtaining and interpreting the vast amounts of obtained data. A protocol and set of data analysis tools were developed to enable quantification and visualization of dynamic 4D-CT data. This methodology was applied to a sample case at 2 time points. In the patient with RS, overall increases in normalized airway caliber were observed from 5 weeks to 1 year. There was, however, continued dynamic obstruction at all airway levels, though objective measures of UAO did improve at the nasopharynx and oropharynx. Use of 4D-CT and novel analyses provide additional quantitative information to evaluate UAO in patients with RS.

Contemporary imaging of the pediatric shoulder: pearls and pitfalls.

In skeletally immature patients, the presence of growth plates and articular cartilage of the shoulder can create a predisposition for unique injuries not observed in adults. Furthermore, increasing participation in sports by children and adolescents appears to be leading to a corresponding increase in the number of sports-related injuries. The importance of radiologists being familiar with pediatric shoulder imaging and its associated injuries is therefore growing. In this article, we review the normal development and maturation pattern of ossification centers of the shoulder from the early gestational period through adolescence. Brachial plexus birth palsy, physeal injuries, shoulder dislocation, and internal impingement are discussed within the context of the child's age and the mechanism of injury to guide radiologists to a correct diagnosis.

Ultrasound Evaluation of Pediatric Slow-Flow Vascular Malformations: Practical Diagnostic Reporting to Guide Interventional Management.

OBJECTIVE. This article reviews the ultrasound characteristics of pediatric slow-flow vascular malformations and underscores findings that significantly impact diagnosis and treatment. Key imaging features are discussed including lesion size, malformation location, morphology, and mimics. CONCLUSION. Ultrasound findings affect the management of slow-flow vascular malformations and should be emphasized in lesion diagnosis. Superficial, focal lesions with well-defined margins are ideal for ultrasound evaluation.