Can Automated 3-Dimensional Dixon-Based Methods Be Used in Patients With Liver Iron Overload?

PURPOSE: Accurate quantification of liver iron concentration (LIC) can be achieved via magnetic resonance imaging (MRI). Maps of liver T2*/R2* are provided by commercially available, vendor-provided, 3-dimensional (3D) multiecho Dixon sequences and allow automated, inline postprocessing, which removes the need for manual curve fitting associated with conventional 2-dimensional (2D) gradient echo (GRE)-based postprocessing. The main goal of our study was to investigate the relationship among LIC estimates generated by 3D multiecho Dixon sequence to values generated by 2D GRE-based R2* relaxometry as the reference standard. METHODS: A retrospective review of patients who had undergone MRI scans for estimation of LIC with conventional T2* relaxometry and 3D multiecho Dixon sequences was performed. A 1.5 T scanner was used to acquire the magnetic resonance studies. Acquisition of standard multislice multiecho T2*-based sequences was performed, and R2* values with corresponding LIC were estimated. The comparison between R2* and corresponding LIC estimates obtained by the 2 methods was analyzed via the correlation coefficients and Bland-Altman difference plots. RESULTS: This study included 104 patients (51 male and 53 female patients) with 158 MRI scans. The mean age of the patients at the time of scan was 15.2 (SD, 8.8) years. There was a very strong correlation between the 2 LIC estimation methods for LIC values up to 3.2 mg/g (LIC quantitative multiecho Dixon [qDixon; from region of interest R2*] vs LIC GRE [in-house]: r = 0.83, P < 0.01; LIC qDixon [from segmentation volume R2*] vs LIC GRE [in-house]: r = 0.92, P < 0.01); and very weak correlation between the 2 methods at liver iron levels >7 mg/g. CONCLUSION: Three-dimensional-based multiecho Dixon technique can accurately measure LIC up to 7 mg/g and has the potential to replace 2D GRE-based relaxometry methods.

Frequency of MRI Low Signal Intensity in the Buccal Fat of Fetuses and Speculation as to What It May Reflect.

PURPOSE: We aimed to characterize the fetal buccal fat pad (BFP) on magnetic resonance imaging (MRI) to determine the frequency and types of sequences on which the BFP demonstrates low signal intensity and determine any possible correlation with timing of the MRI during fetal development. MATERIALS AND METHODS: A retrospective review of all fetal MR studies was performed, and a pediatric radiologist blinded to the referring and final fetal diagnosis as well as outcome evaluated the included cases. A positive buccal fat pad sign (BFS) was recorded as present if a round, symmetric, and bilateral area was seen in the submalar region of the face with the following signal characteristics: T1 hyperintensity, low signal on echo planar imaging (EPI), low signal on true fast imaging with steady-state free precession (TRUFI), and with restriction on diffusion-weighted imaging (DWI). RESULTS: A total of one hundred sixty-seven (167) fetal MRI studies: one hundred fourteen (114) body (68%) and fifty-three (53) neuro (32%) scans were reviewed during the study period. The BFS was most commonly seen on EPI (63%) and TRUFI (49%) sequences. Substantial agreement between TRUFI and EPI (κ = 0.68; p < 0.01); moderate agreement between TRUFI and T1 (κ = 0.53; p < 0.01) as well as T1 and EPI (κ = 0.53; p < 0.01), and fair agreement between EPI and Diffusion (κ = 0.28; p < 0.01) was observed. The median gestational age (GA) was 24 weeks (IQR 22-30 weeks). The fetuses with a positive BFS were significantly older (mean GA of 27 weeks or higher) than those without, for each sequence. CONCLUSIONS: The focal low signal in the fetal buccal fat pad, termed the fetal BFS, is a commonly encountered normal finding in the majority of fetal MRI scans on TRUFI and EPI sequences. This finding may be related to the presence and development of brown adipose tissue in the buccal fat pad resulting in T2* effects, but further studies are needed in order to confirm this. Further work can incorporate any of the sensitive sequences demonstrating low signal in brown adipose tissue to map its distribution and development in the fetus and beyond.

Cryoprobe for endoscopic enucleation in children with pulmonary tuberculosis - effective but not without danger: Case report and review of literature.

INTRODUCTION: Tuberculosis (TB) in children under 15 years often results in airway compression, with bronchus intermedius (BI) being the most common site. Endoscopic enucleations can be used to remove lymph nodes and establish an airway in severe cases. Both rigid and flexible bronchoscopy are suitable, with alligator forceps being preferred for its ability to extract tissue. Recent studies have also explored cryoprobe enucleation. CASE PRESENTATION: An HIV-positive boy with persistent symptoms after 9 months of TB treatment was diagnosed based on his mother's and sister's Xpert MTB/RIF positive status. He was started on 4-drug TB treatment, but the child remained clinically symptomatic with abnormal chest X-ray and unconfirmed TB. Bronchoscopy was performed, revealing complete obstruction of BI due to caseating granulomas causing collapse of the right middle and lower lobes. Cryotherapy was used to recanalise the airway, and follow-up bronchoscopy confirmed patent BI. CONCLUSION: While cryotherapy was effective in the restoration of airway patency in this case, there is a lack of knowledge about its use in children.

Quality and Diagnosis on the Lateral View of Pediatric Upper Gastro-Intestinal Series.

BACKGROUND: The standard imaging technique for the diagnosis of intestinal malrotation remains the upper gastro-intestinal series (UGIS). The lateral view is promoted as important for making a diagnosis. For this, the lateral view should be of adequate quality, and radiologists must know the normal appearance as well as the appearance of duodenal variants, as misdiagnosis may lead to unnecessary surgery. OBJECTIVE: We aimed to evaluate the quality, findings including the prevalence of the "descending staircase" configuration and its correspondence to a diagnosis of duodenum redundum. MATERIALS AND METHODS: This was a retrospective study and was conducted in a large tertiary children's hospital in the United States. A retrospective review of UGI fluoroscopy exams in children aged ≤ 18 years between January and December 2018 was performed by a pediatric radiologist. First, the lateral view images/cine-loops were assessed independently, followed by the anteroposterior (AP) view. The studies which were designated to have an adequate lateral view were evaluated for configuration of the duodenum and recorded as: normal, abnormal, or normal variant. Also, the presence of a descending staircase configuration was correlated with an AP view for a diagnosis of duodenum redundum. RESULTS: A total of 26 children (26%) (males:16; females:10) with age range 0 to 16 years had adequate lateral views during UGI exams for inclusion. Of the 26, 18 (69%) were reported as normal, 7 (27%) were reported as having a descending staircase and 1 (4%) was reported as abnormal. The AP view demonstrated 2 abnormal studies (1 malrotation and 1 non-rotation), 6 duodenum redundum and 18 normal exams. The one abnormal lateral duodenum was confirmed as a non-rotation on AP view; the second patient with an abnormal AP view had a normal appearance on the lateral view. CONCLUSIONS: A total of 26% of UGI studies had adequate lateral views for interpretation. Of these, nearly a quarter (23%) demonstrated the descending stair-case sign corresponding to a diagnosis of duodenum redundum on the AP view. If the lateral view had been used alone, there would have been a missed diagnosis in one patient.

Frequency of Cerebellar Abnormalities Associated With the Differing Magnetic Resonance Imaging Patterns of Term Hypoxic-Ischemic Injury in Children.

BACKGROUND: We aimed to determine the frequency of cerebellar injury using delayed magnetic resonance imaging (MRI) in children with cerebral palsy, diagnosed with term hypoxic-ischemic injury (HII), and to characterize this for the different MRI patterns of HII. METHODS: We retrospectively reviewed delayed MRI scans in children with cerebral palsy, of whom 1175 had term HII. The pattern of HII was classified into basal ganglia-thalamus (BGT) pattern, watershed (WS) pattern, combined BGT/WS, and multicystic HII. Cerebellar location (hemisphere versus vermis) and the MRI characteristics were documented overall and for each of the different patterns of HII, as well as the association with thalamic injury. RESULTS: Cerebellar injury was found in 252 of 1175 (21.4%) (median age 6 years [interquartile range: 3 to 9 years]). Of these, 49% (124 of 252) were associated with a BGT pattern, 13% (32 of 252) with a WS pattern, 28% (72 of 252) with a combined BGT/WS pattern, and 10% (24 of 252) with a multicystic pattern. The vermis was abnormal in 83% (209 of 252), and the hemispheres were abnormal in 34% (86 of 252) (with 17% [43 of 252] showing both vermis and hemispheric abnormality). CONCLUSIONS: Over a fifth of patients with cerebral palsy due to HII had a cerebellar abnormality on delayed MRI, most commonly involving the vermis (83%), and as part of a BGT pattern of injury in just under half of these likely reflecting the association of cerebellar vermis injury with profound insults.

Distinguishing multicystic from focal encephalomalacia on delayed MRI in children with term hypoxic ischemic injury.

BACKGROUND AND PURPOSE: To define cystic patterns resulting from term hypoxic ischemic injury (HII) on delayed Magnetic Resonance Imaging (MRI) and determine associated HII patterns and lesions that reflect the severity of injury, from a database of African children with cerebral palsy. METHODS: Retrospective review of 1175 children with cerebral palsy due to term HII diagnosed on late MRI, identifying those with cystic changes. These were classified as multicystic or (multi-) focal-cystic, and were evaluated for associated injuries-thalami, basal ganglia, hippocampi, cerebellum, and presence of ulegyria. RESULTS: Three hundred and eighty-eight of 1175 (33%) children had cystic encephalomalacia. Two hundred and seven of 388 (53.3%) had focal-cystic and 181/388 (46.6%) had multicystic injury. The focal-cystic group comprised 87.9% (182/207) with thalamic injury, 25.6% (53/207) with basal ganglia injury, and 15% (31/207) with cerebellar involvement. Basal-ganglia-thalamus (BGT) pattern was present in 43.9% (91/207) and ulegyria in 69.6% (144/207). In the multicystic group, 88.9% (161/181) had thalamic injury, 30.9% (56/181) had basal ganglia injury, and 21% (38/181) had cerebellar involvement. BGT pattern was observed in 29.8% (54/181) and ulegyria in 28.7%. (52/181). Significant associations (p<.05) were found between multicystic injury and caudate/globus pallidus involvement, and between focal-cystic pattern of injury and ulegyria. CONCLUSIONS: Cystic encephalomalacia was seen in almost one-third of patients with term HII imaged with delayed MRI, with a similar prevalence of focal-cystic and multicystic injury. Multicystic injury was associated with caudate and globus pallidi involvement, typical of the BGT pattern of HII, whereas the focal-cystic pattern was associated with ulegyria, typical of watershed injury.

Accuracy of non-medical and medical individuals in identifying cerebral cortical abnormality from three-dimensional printed models of magnetic resonance images in children with hypoxic ischemic injury.

Effective communication of imaging findings in term hypoxic ischemic injury to family members, non-radiologist colleagues and members of the legal profession can be extremely challenging through text-based radiology reports. Utilization of three-dimensional (D) printed models, where the actual findings of the brain can be communicated via tactile perception, is a potential solution which has not yet been tested in practice. We aimed to determine the sensitivity and specificity of different groups, comprising trained radiologists, non-radiologist physicians and non-physicians, in the detection of gross disease of the cerebral cortex from 3-D printed brain models derived from magnetic resonance imaging (MRI) scans of children. Ten MRI scans in children of varying ages with either watershed pattern hypoxic ischemic injury (cortical injury) or basal-ganglia-thalamus hypoxic ischemic injury pattern with limited perirolandic cortical abnormalities and 2 normal MRI scans were post processed and 3-D printed. In total, 71 participants reviewed the 12 models and were required to indicate only the brain models that they felt were abnormal (with a moderate to high degree of degree of confidence). The 71 participants included in the study were 38 laypeople (54%), 17 radiographic technologists (24%), 6 nurses (8%), 5 general radiologists (7%), 4 non-radiologist physicians- 3 pediatricians and 1 neurologist (6%) and 1 emergency medical services staff (1%). The sensitivity and specificity for detecting the abnormal brains of the 71 participants were calculated. Radiologists showed the highest sensitivity (72%) and specificity (70%). Non-radiologist physicians had a sensitivity of 67.5% and a specificity of 75%. Nurses had a sensitivity of 70% and a specificity of 41.7%. Laypeople (non-medical trained) had a sensitivity of 56.1% and a specificity of 55.3%. Radiologists' high sensitivity and specificity of 72% and 70%, respectively, validates the accuracy of the 3-D-printed models in reproducing abnormalities from MRI scans. The non-radiologist physicians also had a high sensitivity and specificity. Laypeople, without any prior training or guidance in looking at the models, had a sensitivity of 56.1% and a specificity of 55.3%. These results show the potential for use of the 3-D printed brains as an alternate form of communication for conveying the pathological findings of hypoxic ischemic injury of the brain to laypeople.

Fast magnetic resonance imaging for diagnosing pulmonary tuberculosis in children: the sub-10-min unenhanced scan.

PURPOSE: In this study, we aimed to report the feasibility and quality of fast (unenhanced < 10-min duration) magnetic resonance imaging (MRI) for the detection of lymphadenopathy in non-sedated children with suspected tuberculosis (TB). MATERIAL AND METHODS: This was a prospective study that involved children (< 13 years of age) hospitalised at Red Cross Children's Hospital with suspected pulmonary TB who were referred for a fast MRI of the chest. The limited short-duration MRI protocol included coronal short tau inversion recovery (STIR) and axial diffusion-weighted imaging (DWI) sequences with additional axial STIR and axial and coronal T2 sequences if the patient was compliant. The scan time was capped at 10 min and a study was considered successfully completed when DWI and STIR images were obtained in axial planes. MRI quality was recorded as 'acceptable quality'; 'poor quality, but readable'; and 'non-diagnostic'. RESULTS: Of the 192 fast MRI protocol scans, 166 (86%) were successfully completed within the 10-min allotted scan period. There was no age or sex difference between successful and unsuccessful studies. The mean duration of successful scans was 6.5 min (standard deviation = 1.5 min, range = 4-10 min). CONCLUSION: Fast (sub-10-min scan) MRI is feasible for diagnosis of lymphadenopathy in non-sedated children in the setting of suspected TB, including those below 6 years of age.

Evaluation of the diagnostic performance of physician lung ultrasound versus chest radiography for pneumonia diagnosis in a peri-urban South African cohort.

BACKGROUND: Lung ultrasound (US), which is radiation-free and cheaper than chest radiography (CXR), may be a useful modality for the diagnosis of pediatric pneumonia, but there are limited data from low- and middle-income countries. OBJECTIVES: The aim of this study was to evaluate the diagnostic performance of non-radiologist, physician-performed lung US compared to CXR for pneumonia in children in a resource-constrained, African setting. MATERIALS AND METHODS: Children under 5 years of age enrolled in a South African birth cohort study, the Drakenstein Child Health Study, who presented with clinically defined pneumonia and had a CXR performed also had a  lung US performed by a study doctor. Each modality was reported by two readers, using standardized methodology. Agreement between modalities, accuracy (sensitivity and specificity) of lung US and inter-rater agreement were assessed. Either consolidation or any abnormality (consolidation or interstitial picture) was considered as endpoints. In the 98 included cases (median age: 7.2 months; 53% male; 69% hospitalized), prevalence was 37% vs. 39% for consolidation and 52% vs. 76% for any abnormality on lung US and CXR, respectively. Agreement between modalities was poor for consolidation (observed agreement=61%, Kappa=0.18, 95% confidence interval [95% CI]: - 0.02 to 0.37) and for any abnormality (observed agreement=56%, Kappa=0.10, 95% CI: - 0.07 to 0.28). Using CXR as the reference standard, sensitivity of lung US was low for consolidation (47%, 95% CI: 31-64%) or any abnormality (5%, 95% CI: 43-67%), while specificity was moderate for consolidation (70%, 95% CI: 57-81%), but lower for any abnormality (58%, 95% CI: 37-78%). Overall inter-observer agreement of CXR was poor (Kappa=0.25, 95% CI: 0.11-0.37) and was significantly lower than the substantial agreement of lung US (Kappa=0.61, 95% CI: 0.50-0.75). Lung US demonstrated better agreement than CXR for all categories of findings, showing a significant difference for consolidation (Kappa=0.72, 95% CI: 0.58-0.86 vs. 0.32, 95% CI: 0.13-0.51). CONCLUSION: Lung US identified consolidation with similar frequency to CXR, but there was poor agreement between modalities. The significantly higher inter-observer agreement of LUS compared to CXR supports the utilization of lung US by clinicians in a low-resource setting.

Comparison of chest radiographs against minimum intensity projection reconstruction computed tomography scans for detection of airway stenosis in children with lymphobronchial tuberculosis.

BACKGROUND: Ideally, suspected airway compression in symptomatic children with lymphobronchial tuberculosis (TB) would be diagnosed using modern computed tomography (CT) assisted by coronal minimum intensity projection (MinIP) reconstructions. However, in TB-endemic regions with limited resources, practitioners rely on conventional radiography for diagnosing TB and its complications. Furthermore, airway compression detected on conventional radiographs would upgrade a patient into the severe category according to the new World Health Organization guidelines, precluding the patient from shorter treatment protocols. The accuracy of conventional radiographs in the context of detecting airway compression in children with TB has not been specifically evaluated against an imaging gold standard. OBJECTIVE: We aimed to compare frontal chest radiographs against thick-slab angled coronal CT MinIP in identifying airway stenosis at ten specific sites and to determine observer agreement between the modalities regarding the degree of stenosis. MATERIALS AND METHODS: This retrospective cross-sectional study compared chest radiographs with standardized angled coronal CT MinIP in children with symptomatic lymphobronchial TB at ten predetermined airway locations. Chest radiographs were evaluated by one pediatric radiologist and CT MinIP reconstructions were independently interpreted by three readers. Sensitivity and specificity were calculated using CT MinIP as the gold standard. Stenosis was graded as 1 for mild (1-50%), 2 for moderate (51-75%), 3a for severe (76-99%), and 3b for total occlusion (100%). Agreement between the two modalities regarding severity of stenosis was calculated using the kappa coefficient for each affected site. RESULTS: A total of 37 patients were included in the study. The median age of patients was 14.3 months (interquartile range 8.0-23.2). Three hundred and seventy individual bronchi (10 from each of the 37 patients) were evaluated for stenosis. Chest radiographs showed that 31 out of 37 (84%) patients had stenosis in at least one of ten evaluated sites, most commonly the left main bronchus and bronchus intermedius, and this was confirmed via CT MinIP. The gold standard (CT MinIP) demonstrated stenosis in at least one of ten sites in all 37 patients (100%). Left main bronchus stenosis was detected by chest radiography with a 92.9% sensitivity and 100% specificity. Sensitivity and specificity for bronchus intermedius stenosis were 80% and 75%, respectively. There was substantial agreement for grade of stenosis between chest radiographs and CT (kappa=0.67) for the left main bronchus and moderate agreement (kappa=0.58) for the bronchus intermedius. Severe stenosis was found in 78 bronchi on CT compared to 32 bronchi (Grade 3a: 9, Grade 3b: 23) on chest radiographs. CONCLUSION: The diagnosis of pulmonary TB in children continues to rely heavily on imaging, and we have shown that in young children, chest radiographs had a high sensitivity and specificity for detecting airway stenosis at certain anatomical sites, when adequately visualized, resulting from tuberculous lymph node compression at left main bronchus and bronchus intermedius. For most sites, the interobserver agreement was poor. Stenosis of the left main bronchus and bronchus intermedius should be the focus of chest radiograph interpretation and can assist both diagnosis and classification of patients for treatment.

Unequal Cerebral Magnetic Resonance Imaging Changes in Perinatal Hypoxic Ischemic Injury of Term Neonates.

BACKGROUND: Perinatal hypoxic ischemic injury (HII) has a higher prevalence in the developing world. One of the primary concepts for suggesting that an imaging pattern reflects a global insult to the brain is when the injury is noted to be bilateral and symmetric in distribution. In the context of HII in term neonates, this is either bilateral symmetric ( a ) peripheral/watershed (WS) injury or ( b ) bilateral symmetric basal-ganglia-thalamus (BGT) pattern, often with the peri-Rolandic and hippocampal injury. Unilateral, asymmetric, or unequal distribution of injury may therefore be misdiagnosed as perinatal arterial ischemic stroke. OBJECTIVES: We aimed to determine the prevalence of unequal cerebral injury in HII, identify patterns, and determine their relationship with existing classification of HII. MATERIALS AND METHODS: Review of brain magnetic resonance imaging from a database of children with HII. Reports with any unequal pattern of injury were included and further classified as a unilateral, bilateral asymmetric, or symmetric but unequal degree pattern of HII. RESULTS: A total of 1213 MRI scans in patients with a diagnosis of HII revealed 156 (13%) with unequal involvement of the hemispheres: unilateral in 2 of 1213 (0.2%) (involvement only in the WS), asymmetric in 48 of 1213 (4%) (WS in 6 [0.5%], BGT in 4 [0.3%], and combined BGT and WS in 38 [3.1%]), and bilateral symmetric but unequal degree in 106 of 1213 (8.7%) (WS in 20 [1.6%], BGT in 17 [1.4%], and combined BGT and WS in 69 [5.7%]). CONCLUSIONS: The majority of children with cerebral palsy due to HII demonstrate a characteristic bilateral symmetric pattern of injury. In our study, 13% demonstrated an unequal pattern. Differentiation from perinatal arterial ischemic stroke, which is mostly unilateral and distributed typically in the middle cerebral artery territory, should be possible and recognition of the typical BGT or WS magnetic resonance imaging patterns should add confidence to the diagnosis, in such scenarios.

Caution: shortcomings of traditional segmentation methods from magnetic resonance imaging brain scans intended for 3-dimensional surface modelling in children with pathology.

This technical innovation assesses the adaptability of some common automated segmentation tools on abnormal pediatric magnetic resonance (MR) brain scans. We categorized 35 MR scans by pathologic features: (1) "normal"; (2) "atrophy"; (3) "cavity"; (4) "other." The following three tools, (1) Computational Anatomy Toolbox version 12 (CAT12); (2) Statistical Parametic Mapping version 12 (SPM12); and (3) MRTool, were tested on each scan-with default and adjusted settings. Success was determined by radiologist consensus on the surface accuracy. Automated segmentation failed in scans demonstrating severe surface brain pathology. Segmentation of the "cavity" group was ineffective, with success rates of 23.1% (CAT12), 69.2% (SPM12) and 46.2% (MRTool), even with refined settings and manual edits. Further investigation is required to improve this workflow and automated segmentation methodology for complex surface pathology.

Patient rotation chest X-rays and the consequences of misinterpretation in paediatric radiology.

PURPOSE: We aimed to demonstrate the consequences of rotation on neonatal chest radiographs and how it affects diagnosis. In addition, we demonstrate methods for determining the presence and direction of rotation. BACKGROUND: Patient rotation is common in chest X-rays of neonates. Rotation is present in over half of chest X-rays from the ICU, contributed to by unwillingness of technologists to reposition new-borns for fear of dislodging lines and tubes. There are six main effects of rotation on supine paediatric chest X-rays: 1) unilateral hyperlucency of the side that the patient is rotated towards; 2) the side 'up' appears larger; 3) apparent deviation of the cardiomediastinal shadow in the direction that the chest is rotated towards; 4) apparent cardiomegaly; 5) distorted cardio-mediastinal configuration; and 6) reversed position of the tips of the umbilical artery and vein catheters with rotation to the left. These effects can cause diagnostic errors due to misinterpretation, including air-trapping, atelectasis, cardiomegaly, and pleural effusions, or disease may be masked. We demonstrate the methods of evaluating rotation with examples, including a 3D model of the bony thorax as a guide. In addition, multiple examples of the effects of rotation are provided including examples where disease was misinterpreted, underestimated or masked. CONCLUSION: Rotation is often unavoidable in neonatal chest X-rays, especially in the ICU. It is therefore important for physicians to recognise rotation and its effects, and to be aware that it can mimic or mask disease.

Evolving role of chest radiographs for diagnosis of pediatric pulmonary tuberculosis.

Chest radiographs (CXR) have played an important and evolving role in diagnosis, classification and management of pediatric pulmonary tuberculosis (TB). During the pre-chemotherapy era, CXR aided in determining infectiousness, mainly to guide isolation practices, by detecting calcified and non-calcified lymphadenopathy. The availability of TB chemotherapy from the mid-1900s increased the urgency to find accurate diagnostic tools for what had become a treatable disease. Chest radiographs provided the mainstay of diagnosis in children, despite high inter-reader variability limiting its accuracy. The development of cross-sectional imaging modalities, such as computed tomography, provided more accurate intra-thoracic lymph node assessment, but these modalities have major availability, cost and radiation exposure disadvantages. As a consequence, CXR remains the most widely used modality for childhood  pulmonary TB diagnosis, given its relatively low cost and accessibility. Publication of the revised 2022 World Health Organization Consolidated TB guidelines added practical value to CXR interpretation in children, by allowing the selection of children for shorter TB treatment using radiological signs of severity of disease, that have high reliability. This article provides a review of the historical journey and evolving role of CXR in pediatric pulmonary TB.

Natural History of Chiari 1 Deformity.

PURPOSE: Chiari type 1 deformity (Ch1) is associated with bony deformity of the skull base and herniation of cerebellar tonsils more than 5 mm below the foramen magnum. Magnetic resonance imaging (MRI) is used for diagnosis and surgery is advised for symptomatic children. We present a case series using MRI including cerebrospinal fluid (CSF) flow, in children with Ch1 to demonstrate a variety of outcomes, both surgical and spontaneous: spontaneous resolution, spontaneous worsening, postsurgical improvement, and postsurgical deterioration. CASE: A 2-week-old female newborn underwent brain MRI demonstrating an ectopic neurohypophysis, under opercularization suggesting brain immaturity and a normal craniocervical junction (CCJ). Follow-up (F/U) MRI at 6 years of age showed interval spontaneous development of Ch1 with decreased CSF spaces at CCJ. CASE: A 6-year-old girl referred for imaging with short stature and growth hormone deficiency demonstrated incidental findings of Ch1 without syringomyelia. There was 15-mm protrusion of pointed cerebellar tonsils through the foramen magnum and a reduced CSF space at the craniocervical junction. No surgery was performed, and F/U MRI at the age of 7 years demonstrated spontaneous resolution of the tonsillar ectopia (cerebellar tonsils now 3 mm right and 6 mm left) and expansion of the CSF spaces at CCJ. CASE: A 7-year-old boy with headaches and staring spells underwent an MRI demonstrating 6-mm protrusion of pointed cerebellar tonsils and CSF space reduction at CCJ. No surgery was performed, and F/U imaging at the age of 9 years demonstrated spontaneous improvement in cerebellar tonsillar position and increased bidirectional CSF flow at CCJ. CASE: A 17-month-old boy underwent brain MRI for unsteady gait and poor vestibular response, which showed Ch1 and narrow CSF spaces at the foramen magnum and with reduced CSF flow. At the age of 3 years, after posterior fossa decompression, F/U MRI showed postsurgical improvement of the position of the cerebellar tonsils and increased CSF space at CCJ. CASE: A 4-month-old male infant with a history of 34-week prematurity, prior germinal matrix hemorrhage, and neonatal subdural hemorrhage was referred for MRI of the cervical and thoracic spine for evaluation of developmental delay and hypotonia with torticollis. Magnetic resonance imaging of the spine demonstrated mild protrusion of inferiorly pointed cerebellar tonsils up to the foramen magnum, with visible CSF and without retroflexion of the dens. Follow-up MRI scans demonstrated progressive worsening of the Chiari 1 deformity, even after multiple surgeries. CONCLUSIONS: It is important to be aware of a variety of different outcomes with Ch1, including spontaneous resolution, spontaneous worsening, improvement with surgery, and even deterioration after surgery. More research is required to determine objective criteria for predicting outcome, which include both anatomic measures and physiologic measures of CSF flow, so that better surgical decisions can be made and for evaluating patients who have undergone surgery.

Distribution of IntraThalamic Injury According to Nuclei and Vascular Territories in Children With Term Hypoxic-Ischemic Injury.

BACKGROUND: Term hypoxic-ischemic injury (HII) on magnetic resonance imaging (MRI) is described as the basal ganglia thalamus [BGT], watershed [WS], or combined [BGT/WS] groups. We aimed to determine differences between HII groups in intrathalamic distribution. METHODS: Delayed MRIs of children with HII and thalamic injury were reviewed. Custom tools were placed over T2-weighted and/or fluid-attenuated inversion recovery axial images to determine distribution of intrathalamic injury: (1) six subjective (whole/near-whole, central, anterior, posterior, lateral, medial); (2) four nuclear (anterior [AN], ventrolateral [VLN], medial [MN], and pulvinar [PN]); and (3) three arterial (thalamoperforating arteries [TPA], thalamogeniculate arteries [TGA], and posterior choroidal arteries [PCA]) locations. We compared the frequency of injury of the aforementioned intrathalamic locations between HII groups. RESULTS: The 128 children (mean age at MRI 7.35 ± 3.6 years) comprised 41% (n = 53) BGT, 26% (n = 33) WS, and 33% (n = 42) BGT/WS. The VLN was the most frequent injured nuclear region (66%, n = 85), and the TGA (93%, n = 128) was the most frequent arterial region involved. VLN injury occurred more frequently in the BGT group (P < 0.001), PN in the WS group (P < 0.001), and AN (P < 0.001), MN (P < 0.001), PN (P = 0.001), and all nuclei together (P < 0.001) in the BGT/WS group. The combination of all vascular territories was significantly associated with BGT/WS (P < 0.001). CONCLUSIONS: There are significant differences in intrathalamic nuclear and arterial injuries between the different types of HII.

Frequency of ulegyria on delayed MRI scans in children with term hypoxic-ischemic injury.

BACKGROUND: Ulegyria is an under-recognized and underreported potential sequela of hypoxic-ischemic injury (HII) in full-term neonates. Ulegyria is a unique form of parenchymal scarring that leads to a mushroom-shape of the affected gyri resulting from volume loss at the deep portions of the sulci during HII in this specific period in infantile neurodevelopment. Identifying ulegyria is important for ascribing cause and timing of HII on delayed magnetic resonance imaging (MRI) scans and because of its close association with pharmaco-resistant epilepsy. OBJECTIVE: The purpose of this study was to determine the frequency of ulegyria and characterize the anatomical distribution of watershed injury in a large database of patients who developed cerebral palsy with term HII pattern and underwent delayed MRI. MATERIALS AND METHODS: Patients with term HII patterns on MRI were analyzed for ulegyria. The frequency of ulegyria overall and for each pattern of HII distribution was determined as was the anatomical distribution of watershed injury. RESULTS: Of the 731 children with term HII and cortical injury, 484 (66%) had ulegyria. Ulegyria was most common in those cases with a combined watershed/basal ganglia-thalamic pattern (56%) and isolated watershed pattern (40%). Watershed injury in patients with ulegyria was most common at the posterior watershed (80.6%) and perisylvian watershed (76.7%). CONCLUSION: Ulegyria was present in nearly two-thirds of patients with term HII and cortical injury and should be sought to support the diagnosis of previous perinatal HII, especially in posterior and perisylvian watershed regions. The implications of ulegyria can be significant for clinical decision-making and for ascribing timing of injury to the perinatal period.

Rate of Change of Liver Iron Content by MR Imaging Methods: A Comparison Study.

Objective: Magnetic resonance imaging (MRI) can accurately quantify liver iron concentration (LIC), eliminating the need for an invasive liver biopsy. Currently, the most widely used relaxometry methods for iron quantification are R2 and R2*, which are based on T2 and T2* acquisition sequences, respectively. We compared the rate of change of LIC as measured by the R2-based, FDA-approved commercially available third-party software with the rate of change of LIC measured by in-house analysis using R2*-relaxometry-based MR imaging in patients undergoing follow-up MRI scans for liver iron estimation. Methods: We retrospectively included patients who had undergone serial MRIs for liver iron estimation. The MR studies were performed on a 1.5T scanner; standard multi-slice, multi-echo T2- and T2*-based sequences were acquired, and LIC was estimated. The comparison between the rate of change of LIC by R2 and R2* values was performed via correlation coefficients and Bland−Altman difference plots. Results: One hundred and eighty-nine MR abdomen studies for liver iron evaluation from 81 patients (male: 38; female: 43) were included in the study. Fifty-nine patients had two serial scans, eighteen patients had three serial scans, three patients had four serial scans, and one patient had five serial scans. The average time interval between the first and last scans for each patient was 13.3 months. The average rates of change of LIC via R2 and R2* methods were −0.0043 ± 0.0214 and −0.0047 ± 0.012 mg/g per month, respectively. There was no significant difference in the rate of change of LIC observed between the two methods. Linearity between the rate of change of LIC measured by R2 (LIC R2) and R2* (LIC R2*) was strong, showing a correlation coefficient of r = 0.72, p < 0.01. A Bland−Altman plot between the rate of change of the two methods showed that the majority of the plotted variables were between two standard deviations. Conclusion: There was no significant difference in the rate of change of LIC detected between the R2 method and the R2* method that uses a gradient echo (GRE) sequence acquired with breath-hold. Since R2* is relatively faster and less prone to motion artifacts, R2*-derived LIC is recommended for iron homeostasis follow-up in patients with liver iron overload.

Can the Third Part of Duodenum Behind SMA Be Detected With Confidence on CT as a Proposed Mechanism for Imaging Suspected Malrotation in Children? A Preliminary Proof of Concept Study.

AIM: The aims of this study were to determine frequency and reliability of computed tomography (CT) detection of anatomic landmarks for imaging suspected midgut malrotation in infants and children, and to calculate an estimated effective dose of an upper abdominal CT scan in our patient population. MATERIALS AND METHODS: Fifty consecutive pediatric patients who underwent a CT scan that included their upper abdomen between August 2016 and February 2018 were included. Four pediatric radiology consultants independently reviewed CT scans for detection of the third part of the duodenum and defined their confidence level of this through identification of continuity with the pyloric antrum, D1, D2, and D4 components of the duodenum, as well as the duodenojejunal flexure.Interobserver variability was assessed using Fleiss κ for agreement. A dose estimate, per scan, was calculated using the scanner dose-length product and published conversion factors by Deak. RESULTS: Thirty patients were boys. The average age was 7.5 ± 5.4 years (6 days to 16 years). The D3 segment was definitely identified in 70% of scans, with 68% to 73%, moderate agreement between the readers and a Fleiss κ of 0.47 to 0.52. The DJ flexure was definitely identified in only 30.5% cases, with 35%, poor agreement between readers (Fleiss κ of 0.03). The average estimated dose for a targeted CT scan of the abdomen was 0.9 mSv (0.04-2.4 mSv). CONCLUSIONS: The third part of the duodenum, which is integral in excluding malrotation on cross-sectional studies, was "definitely" identified in 70% of CT scans of children in our study, with 68% to 73% agreement between the readers and a Fleiss κ of 0.47 to 0.52.These preliminary proof of concept results demonstrating a combination of a comparable CT dose in relation to upper gastrointestinal contrast studies and an acceptable number of cases delineating the third part of the duodenum with moderate agreement are a first step in suggesting low-dose CT for an imaging diagnosis of malrotation. Malrotation can be excluded in cases where D3 is well demonstrated in the normal position, which negates the need to automatically refer children with bilious emesis to specialist centers for upper gastrointestinal contrast studies.

Two-dimensional (2D) morphologic measurements can quantify the severity of liver disease in children with autosomal recessive polycystic kidney disease (ARPKD).

PURPOSE: To evaluate the correlation of 2D shape-based features with magnetic resonance elastography (MRE)-derived liver stiffness and portal hypertension (pHTN) in children with ARPKD-associated congenital hepatic fibrosis. METHODS: In a prospective IRB-approved study, 14 children with ARPKD (mean age ± SD = 13.8 ± 5.8 years) and 14 healthy controls (mean age ± SD = 13.7 ± 3.9 years) underwent liver MRE. A 2D region of interest (ROI) outlining the left liver lobe at the level of the abdominal aorta was drawn on sagittal T2-weighted images. Eight shape features (perimeter, major axis length, maximum diameter, perimeter to surface ratio (PSR), elongation, sphericity, minor axis length, and mesh surface) describing the 2D-ROI were calculated. Spearman's correlation was calculated between shape features and MRE-derived liver stiffness (kPa) (n = 28). Shape features were compared between participants with ARPKD with pHTN (splenomegaly and thrombocytopenia), (n = 4) and without pHTN (n = 8) using the Mann Whitney U test. Receiver operating characteristic (ROC) curves were generated to examine the diagnostic accuracy of shape features in identifying cases with liver stiffness > 2.9 kPa. RESULTS: In ARPKD participants and healthy controls, all eight shape features, except elongation, showed moderate to strong correlation with liver stiffness (kPa); the perimeter surface ratio had the strongest correlation (rho = - 0.75, p < 0.001). In ROC analysis, a cut-off of PSR ≤ 0.057 mm-1 gave 100% (95% CI: 59.0-100.0) sensitivity and 100% (95% CI: 83.9-100.0) specificity in identifying ARPKD participants with liver stiffness > 2.9 kPa, with an area under the ROC curve (AUC) of 1.0 (95% CI: 0.88-1.00). Individuals with pHTN had a lower median PSR (mean ± SD = 0.05 ± 0.01) than those without (0.07 ± 0.01; p = 0.027) with an AUC of 0.91 (95% CI: 0.60-0.99) in differentiating the participants with and without pHTN. CONCLUSION: Shape-based features of the left liver lobe show potential as non-invasive biomarkers of liver fibrosis and portal hypertension in children with ARPKD.