How we do it: Cardiac implantable devices are not a contraindication to MRI: time for a paradigm shift.

Magnetic resonance imaging (MRI) is now an indispensable diagnostic tool in medicine due to its outstanding contrast resolution and absence of radiation exposure, enabling detailed tissue characterization and three-dimensional anatomical representation. This is especially important when evaluating individuals with congenital heart disease (CHD) who frequently require cardiac implantable electrical devices (CIEDs). While MRI safety issues have previously limited its use in patients with CIEDs, new advances have called these limitations into question. However, difficulties persist in the pediatric population due to the continued lack of specific safety data both related to imaging young children and the specific CIED devices they often require. This paper discusses MRI safety considerations related to imaging patients with CIEDs, investigates pediatric-specific problems, and describes thorough methods for safe MRI access, highlighting the significance of specialized institutional guidelines.

Dynamic airway computed tomography and flexible bronchoscopy for diagnosis of tracheomalacia in children: A comparison study.

INTRODUCTION: Tracheomalacia (TM) is an important cause of respiratory morbidity. Dynamic flexible bronchoscopy is considered the gold standard for diagnosis. Dynamic airway computed tomography (DACT) is a low radiation, noninvasive diagnostic tool utilizing images obtained continuously over several respiratory cycles. We aimed to assess the accuracy of DACT in TM diagnosis. METHODS: Retrospective analysis of all patients who underwent both DACT and flexible bronchoscopy within 6 months. Airway anterior-posterior (AP) diameter was measured on multiplanar reconstructions CT in both the inspiratory and expiratory phases. Using still images from the bronchoscopy videos, the AP diameter of the trachea was measured at points of maximal and minimal diameter during tidal breathing. Degree of TM on both DACT and flexible bronchoscopy were graded using a scaling system of 50%-74%, 75%-89%, and 90%-100% as described by the European Respiratory Society. RESULTS: Twenty-four patients met inclusion criteria with an average time of 19.5 days between CT and bronchoscopy. The specificity and sensitivity of DACT for the overall diagnosis of TM was 100% and 68%, respectively, with a positive predictive value of 100% and a negative predictive value of 62%. There was a strong positive correlation between DACT and flexible bronchoscopy in the measurement of tracheal AP diameter changes (ρ = 0.773, R2 0.597, p = 0.00001). Mean effective radiation dose for DACT was 0.1 mSv. CONCLUSION: Ultralow dose DACT has excellent specificity and positive predictive value for both detection of TM and categorizing severity of tracheal collapse but is not sufficiently sensitive to rule it out.

Pulmonary injury after radioactive iodine therapy in pediatric papillary thyroid cancer: a case report.

INTRODUCTION: Radiation-induced lung injury is a rare complication of radioactive iodine therapy (RAIT) in pediatric thyroid cancer treatment. In this case report, we describe a pediatric patient with an ERC1::RET-positive classic papillary thyroid carcinoma who developed progressive respiratory symptoms and chest imaging abnormalities following RAIT for lymph node and pulmonary disease. CASE PRESENTATION: A pediatric patient with ERC1::RET-positive classic papillary thyroid carcinoma was hospitalized for pulmonary decompensation three months following one empiric dose of RAIT. Testing revealed no evidence of infection or progression of pulmonary metastases, and there was no improvement with empiric antibiotic therapy for pneumonia. Despite empiric anti-inflammatory therapies, the patient remains symptomatic from a respiratory standpoint with requirement for supplemental oxygen and evidence of fibrotic changes on chest imaging. CONCLUSIONS: This patient's pulmonary condition is consistent with radiation-induced pulmonary injury including development of pulmonary fibrosis. With the availability of RET fusion targeted inhibitors, this case highlights a rare pulmonary side effect of radioactive iodine for clinicians to recognize. Upfront targeted therapy protocols may help avoid radioactive iodine-associated adverse reactions.

Dynamic contrast-enhanced MR lymphangiography: feasibility of using ferumoxytol in patients with chronic kidney disease.

PURPOSE: To assess the feasibility of direct intra-lymphatic administration of diluted ferumoxytol as a T1-positive contrast agent for dynamic contrast-enhanced MR lymphangiography (DCMRL) imaging of the central lymphatics in children with renal disease. METHODS: In vitro scan of dilute ferumoxytol was initially performed using time-resolved and high-resolution 3D gradient echo (GRE) sequences with short TE values (1 to 1.5 ms). A ferumoxytol concentration of 0.25 to 0.40 mg/mL was found to retain high signal in the T1-weighted sequences. DCMRL was then performed in 4 children with renal disease with the same 3D GRE sequences administrating diluted ferumoxytol via intra-mesenteric (IM), intra-hepatic (IH), and intra-nodal (IN) routes (6 to 9 mL to each site; average total dose of 0.75 mg/kg) by slow hand injection (0.5 to 1.0 mL/min). The signal-to-noise ratio (SNR) of the lymphatics was measured for quantitative evaluation. RESULTS: Ferumoxytol-enhanced DCMRL was technically successful in all patients. Contrast conspicuity within the lymphatics was sufficient without subtraction. The mean SNR was significantly higher than the muscle (50.1 ± 12.2 vs 13.2 ± 2.8; t = 15.9; p < .001). There were no short-term complications attributed to the administration of ferumoxytol in any of the four patients. CONCLUSION: Magnetic resonance lymphangiography using ferumoxytol via IN, IH, and IM access is a new method to directly visualize the central lymphatic system and can be applied safely in patients with renal failure based on our preliminary report of four cases. Ferumoxytol-enhanced DCMRL shows diagnostic image quality by using 3D GRE sequences with short TE values and appropriate dilution of ferumoxytol. KEY POINTS: • MR lymphangiography using ferumoxytol via intra-nodal, intra-hepatic, and intra-mesenteric access is a new method to directly visualize the central lymphatic system from the groin to the venous angle. • FDCMRL can be applied safely in patients with renal failure based on our preliminary report of four cases. • FDCMRL shows diagnostic image quality by using 3D GRE sequences with short TE values and appropriate dilution of the ferumoxytol.

Mediastinal Masses in Children: Radiologic-Pathologic Correlation.

Most pediatric masses in the chest are located in the mediastinum. These masses are often initially detected incidentally on chest radiographs in asymptomatic children, although some patients may present with respiratory symptoms. At chest radiography, the mediastinum has been anatomically divided into anterior, middle, and posterior compartments. However, with the International Thymic Malignancy Interest Group classification scheme, which is based on cross-sectional imaging findings, the mediastinum is divided into prevascular, visceral, and paravertebral compartments. In the prevascular compartment, tumors of thymic origin, lymphomas, germ cell tumors, and vascular tumors are encountered. In the visceral compartment, lymphadenopathy and masses related to the foregut are seen. In the paravertebral compartment, neurogenic tumors are most common. Using the anatomic location in combination with knowledge of the imaging and pathologic features of pediatric mediastinal masses aids in accurate diagnosis of these masses to guide treatment and management decisions. An invited commentary by Lee and Winant is available online. ©RSNA, 2021.

Pediatric Lung MRI: Currently Available and Emerging Techniques.

OBJECTIVE. The purpose of this article is to review currently available and emerging techniques for pediatric lung MRI for general radiologists. CONCLUSION. MRI is a radiation-free alternative to CT, and clearly understanding the strengths and limitations of established and emerging techniques of pediatric lung MRI can allow practitioners to select and combine the optimal techniques, apply them in clinical practice, and potentially improve early diagnostic accuracy and patient management.

Current and Future Applications of Thoracic Dual-Energy CT in Children: Pearls and Pitfalls of Technique and Interpretation.

Dual-energy computer tomography (DECT) technology has experienced rapid growth in recent years, now allowing for the collection of 2 CT data sets and opening the potential for functional data acquisition. Data from a single postcontrast phase are deconstructed and Iodine can be subtracted to create a virtual noncontrast image, or selectively represented as a contrast map that allows for the qualification and quantification of lung perfusion. Virtual monoenergetic images can also be used to reduce beam-hardening artifact from concentrated contrast or metal implants. In children, DECT is of particular interest because it has been shown to be dose neutral in most applications, dose-reducing in multiphase studies, and to increase the contrast to noise ratio in suboptimal studies. We review the basics of acquisition, postprocessing, and thoracic applications of DECT with a focus on pulmonary blood volumes as a surrogate for perfusion imaging. The discussed applications include pulmonary embolism, hypoplastic lung, pulmonary hypertension in bronchopulmonary dysplasia, and pediatric lung masses.

Pearls and Pitfalls in Pediatric Fontan Operation Imaging.

The Fontan operation or the total cavopulmonary connection is a palliative surgery for single ventricle congenital heart disease where the systemic venous return circumvents a pumping chamber and flows directly into the pulmonary circuit. With surgical and medical advances, there has been improvement in life expectancy of these patients, however, it has also resulted in unique complications from the physiology that requires diligent surveillance. A critical component relies on optimal imaging for diagnosis and treatment of these complications. This article describes the normal anatomy of the Fontan circulation, current imaging modalities and techniques, and frequently encountered complications seen when imaging the patients who have undergone Fontan palliation.

Clinical and radiological characteristics of e-cigarette or vaping product use associated lung injury.

PURPOSE: E-cigarette or vaping product use associated lung injury (EVALI) has received national attention as an epidemic resulting in cases of significant morbidity and mortality. We aim to present the clinical and imaging findings in adolescents with pulmonary symptoms from suspected EVALI. METHODS: Chest radiographs and CTs of adolescents (< 19 years) with acute pulmonary symptoms and history of vaping were reviewed by two radiologists in consensus. Clinical presentation and laboratory data were derived from the electronic medical records including pulmonary function tests (PFTs). RESULTS: Eleven patients were identified (9 male, mean 16.6 years). The most common presentation was progressive, subacute respiratory distress with abdominal pain. All but one of the patients tested positive for tetrahydrocannabinol. Chest radiograph features were notable for interstitial pattern of opacities (91%) and basilar abnormalities (82%). CT features were notable for ground-glass opacities (89%), interstitial opacities (78%), and subpleural sparing (67%). Eight patients underwent PFTs. Six had diffusing capacity measurement, which demonstrated impaired diffusion in 3 (50%). All patients received supportive treatment with supplemental oxygen and corticosteroids. CONCLUSION: Adolescents with suspected EVALI commonly present with subacute respiratory distress with abdominal pain. Imaging findings include ground-glass opacities, subpleural sparing, and basilar opacities, most consistent with organizing pneumonia or hypersensitivity pneumonitis. Recognition of the common imaging findings may have significant patient management implications, especially if the diagnosis is not suspected clinically. The lung function effects of vaping are consistent with mildly reduced airflow, which improves on follow-up testing, and reduced diffusion capacity, which, concerningly, does not improve.

Diagnostic performance of CT angiography to detect pulmonary vein stenosis in children.

To assess the diagnostic efficiency of CT angiography (CTA) to detect pulmonary vein stenosis in children. We retrospectively identify patients between 0 and 3 years old with confirmed pulmonary vein stenosis with conventional angiography or surgery and available CTA. Patients without confirmed stenosis of the pulmonary veins were included as controls. We excluded patients with previous surgery involving the pulmonary veins, exclusively right-heart conventional angiography or insufficient data in the operation note to confirm the status of the pulmonary veins. Two pediatric radiologists evaluated and determine the presence of stenosis and the pulmonary veins affected. Disagreement between the readers were solved by consensus with a third reader. A pediatric cardiologist reviewed the available angiographic images to determine the presence of stenosis. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. Kappa statistics was performed. 26 patients (15 boys, 11 Girls) were included. Conventional angiography (n = 20) and cardiothoracic surgery (n = 6) confirmed the diagnosis of pulmonary vein stenosis in 13 children. The diagnostic performance at patient level showed the sensitivity, specificity, PPV, and NPV were 84.6%, 92.3%, 91.6%, 87.5%, and 88.4%, respectively. The interobserver was k = 0.76. The performance at pulmonary vein level showed the sensitivity, specificity, PPV, and NPV were 63.3%, 97.4%, 90.4%,85.7% and 87.9%, respectively. The interobserver agreement was k = 0.62. Computed Tomography Angiography is an excellent and reliable image technique for ruling in pulmonary vein stenosis in young children.

Diffuse esophageal leiomyomatosis: A case report with surgical correlation.

A 15 year old female with a history only significant for long standing dysphagia and intermittent chest pain underwent a screening chest radiograph. Findings of a large mass prompted cross sectional imaging where extensive and marked diffuse esophageal thickening was demonstrated. The patient ultimately underwent biopsy and surgical resection for diffuse esophageal leiomyomatosis. Diffuse leiomyomatosis of the esophagus has been described in the literature for about 100 years with increasing recognition in more recent times. There is a known association with inherited syndromes such as Alport and Esophageal-Vulvar syndrome, though some cases are sporadic. This case report will demonstrate the imaging features of diffuse esophageal leiomyomatosis utilizing multiple modalities including radiography, fluoroscopy, CT, and MRI, with surgical and pathologic correlation.

Giant hepatic regenerative nodules in Alagille syndrome.

BACKGROUND: Children with Alagille syndrome undergo surveillance radiologic examinations as they are at risk for developing cirrhosis and hepatocellular carcinoma. There is limited literature on the imaging of liver masses in Alagille syndrome. We report the ultrasound (US) and magnetic resonance imaging (MRI) appearances of incidental benign giant hepatic regenerative nodules in this population. OBJECTIVE: To describe the imaging findings of giant regenerative nodules in patients with Alagille syndrome. MATERIALS AND METHODS: A retrospective search of the hospital database was performed to find all cases of hepatic masses in patients with Alagille syndrome during a 10-year period. Imaging, clinical charts, laboratory data and available pathology were reviewed and analyzed and summarized for each patient. RESULTS: Twenty of 45 patients with confirmed Alagille syndrome had imaging studies. Of those, we identified six with giant focal liver masses. All six patients had large central hepatic masses that were remarkably similar on US and MRI, in addition to having features of cirrhosis. In each case, the mass was located in hepatic segment VIII and imaging showed the mass splaying the main portal venous branches at the hepatic hilum, as well as smaller portal and hepatic venous branches coursing through them. On MRI, signal intensity of the mass was isointense to liver on T1-weighted sequences in four of six patients, but hyperintense on T1 in two of six patients. In all six cases, the mass was hypointense on T2- weighted sequences. The mass post-contrast was isointense to adjacent liver in all phases in five the cases. Five out of six patients had pathological correlation demonstrating preserved ductal architecture confirming the final diagnosis of a regenerative nodule. CONCLUSION: Giant hepatic regenerative nodules with characteristic US and MR features can occur in patients with Alagille syndrome with underlying cirrhosis. Recognizing these lesions as benign giant hepatic regenerative nodules should, thereby, mitigate any need for intervention.