Paul G. Thacker

Congenital lung anomalies in children and adults: current concepts and imaging findings.

This article presents the broad spectrum of congenital lung anomalies, which manifest both in childhood and can be first identified in the adult patient. Each lesion is described in terms of underlying cause, clinical presentation, imaging characteristics with emphasis on advanced cross-sectional imaging, and current treatment options. Up-to-date knowledge of currently available imaging studies and techniques as well as a clear knowledge of imaging characteristics of various congenital lung anomalies are essential for accurate diagnosis and optimal management.

Pulmonary Embolism in Children

OBJECTIVE Pediatric pulmonary thromboembolism (PE) has historically been considered a rare entity with relatively little published in the medical literature. The purpose of this article is to bridge some of the current knowledge gap regarding PE by presenting a comprehensive review of the topic, including discussion of its epidemiology, pathophysiology, clinical manifestations, nonimaging diagnostic examinations, imaging evaluation, treatment and prognosis, and future imaging research directions. CONCLUSION Imaging plays a key role in the evaluation of pediatric PE, and imaging technology will continue to improve. CT will likely remain a first-line diagnostic modality with newer techniques such as dual-energy CT having the potential to become more widely used while improving sensitivity and specificity for small and distal PE. Alternatively, given its lack of ionizing radiation and high sensitivity and specificity when technically adequate, MRI is appealing and may become a viable first-line substitute to CT.

The incidental pulmonary nodule in a child. Part 1: recommendations from the SPR Thoracic Imaging Committee regarding characterization, significance and follow-up.

No guidelines are in place for the follow-up and management of pulmonary nodules that are incidentally detected on CT in the pediatric population. The Fleischner guidelines, which were developed for the older adult population, do not apply to children. This review summarizes the evidence collected by the Society for Pediatric Radiology (SPR) Thoracic Imaging Committee in its attempt to develop pediatric-specific guidelines.Small pulmonary opacities can be characterized as linear or as ground-glass or solid nodules. Linear opacities and ground-glass nodules are extremely unlikely to represent an early primary or metastatic malignancy in a child. In our review, we found a virtual absence of reported cases of a primary pulmonary malignancy presenting as an incidentally detected small lung nodule on CT in a healthy immune-competent child.Because of the lack of definitive information on the clinical significance of small lung nodules that are incidentally detected on CT in children, the management of those that do not have the typical characteristics of an intrapulmonary lymph node should be dictated by the clinical history as to possible exposure to infectious agents, the presence of an occult immunodeficiency, the much higher likelihood that the nodule represents a metastasis than a primary lung tumor, and ultimately the individual preference of the child’s caregiver. Nodules appearing in children with a history of immune deficiency, malignancy or congenital pulmonary airway malformation should not be considered incidental, and their workup should be dictated by the natural history of these underlying conditions.

Developmental lung malformations in children: recent advances in imaging techniques, classification system, and imaging findings.

Congenital lung anomalies represent a diverse group of developmental malformations of the lung parenchyma, arterial supply, and venous drainage, which may present anywhere from the prenatal period through adulthood. It is imperative for radiologists to be aware of imaging techniques and imaging appearance of these anomalies across the pediatric age range. This review presents the spectrum of these lesions that are often encountered in daily clinical practice. Each anomaly is discussed in terms of underlying etiology, clinical presentation, and imaging characterization with emphasis on the most up-to-date research and treatment. Knowledge of these areas is essential for accurate, timely diagnosis, which aids in optimizing patient outcomes.

The incidental pulmonary nodule: an impetus for guidelines

Sir, Every couple of months for the last several years, I find myself in a quandary about what to recommend for solitary and multiple non-calcified pulmonary nodules incidentally found on a pediatric chest CT exam. I am not speaking of those CTs ordered in the setting of pediatric oncology, but the occasional CT ordered by our referring clinicians for the workup of symptoms such as chronic cough. All too often, I find small (less than 1 cm) incidental nodules. Every fiber of my being screams that these are benign and of no clinical significance. However, sticking to the mantra of evidencebased medicine, I dutifully search the literature for articles or guidelines that tell me how these should be followed. I have not found any paper or guideline providing direction. For nearly a decade now, our adult colleagues have had guidelines published by our esteemed thoracic radiology leaders in the Fleischner Society [1]. There are size criteria and recommendations for follow-up imaging for the incidentally detected non-calcified pulmonary nodule. However the society did make one caveat: the guidelines only apply to individuals older than 35 years. In fact, a follow-up study by Feely and Hartman [2] found that the criteria were inappropriately used in 4% of cases for patients younger than 35 years [2]. However, if there is no guidance available in the literature can any of us blame other radiologists in today’s medico-legal environment for using the Fleischner guidelines rather than making up some arbitrary means of follow-up or simply dismissing the findings? Most pediatric radiologists are likely aware that incidental non-calcified pulmonary nodules, in the absence of known malignancy, are almost certainly benign in children. Furthermore what concerns adult imagers and not us (pediatric radiologists) is primary lung malignancy, which is exceedingly rare in those younger than 35, representing less than 1% of all cases. This fact was generally addressed in the Fleischner Society paper, which states that it is reasonable to follow up these incidental nodules with a CT in 6–12 months [1]. Does this suffice? There is no evidence to support or refute it. Also, would a general radiologist who almost certainly interprets more adult CTs than pediatric ones be more likely to use the Fleischner criteria in a child? Again, one cannot be sure. In the end, we will most likely not have studies with sufficient numbers of individuals to prove the benignity of incidental pulmonary nodules in children. For one, most of us likely do not follow them, at least not to the level performed in adults. Second, we have an ethical imperative to keep radiation doses low in our children. A prospective study would be something few of us would like to undertake. Therefore, we are back to what I have searched for over the years, i.e. guidelines. Is it time for us to come together as a society to develop a standard to follow in children? I think the answer is likely yes.

Imaging Evaluation of Mediastinal Masses in Children and Adults: Practical Diagnostic Approach Based on A New Classification System.

A compartmental approach to the diagnosis of the mediastinal masses in children and adults has been widely used to facilitate the diagnosis and planning of diagnostic interventions and surgical treatment for many years. Recently, a new computed tomography–based mediastinal division scheme, approved by the International Thymic Malignancy Interest Group, has received considerable attention as a potential new standard. In this review article, this new computed tomography–based mediastinal division scheme is described and illustrated. In addition, currently used imaging modalities and techniques, practical imaging algorithm of evaluating mediastinal masses, and characteristic imaging findings of various mediastinal masses that occur in children and adults are discussed. Such up-to-date knowledge has the potential to facilitate better understanding of mediastinal masses in both pediatric and adult populations.

The Role of Limited Head Computed Tomography in the Evaluation of Pediatric Ventriculoperitoneal Shunt Malfunction.

Background The evaluation of children with suspected ventriculoperitoneal shunt (VPS) malfunction has evolved into a diagnostic dilemma. This patient population is vulnerable not only to the medical risks of hydrocephalus and surgical complications but also to silent but harmful effects of ionizing radiation secondary to imaging used to evaluate shunt efficacy and patency. The combination of increased medical awareness regarding ionizing radiation and public concern has generated desire to reduce the reliance on head computed tomography (CT) for the evaluation of VPS malfunction. Many centers have started to investigate the utility of low-dose CT scans and alternatives, such as fast magnetic resonance imaging for the investigation of VP shunt malfunction in order to keep radiation exposure as low as reasonably achievable. This pilot study hopes to add to the armamentarium available to the clinician charged with evaluating this challenging patient population by testing the feasibility of a limited CT protocol as an alternative to a full head CT examination. Objective To evaluate the efficacy of a limited head CT protocol compared with a complete head CT for the evaluation of children presenting to the pediatric emergency department with suspected shunt malfunction. Methods We retrospectively reviewed all pediatric patients who received a head CT for suspected VPS malfunction evaluation at a tertiary care childrens hospital from January 2001 through January 2013. Children were included in the pilot study if they had at least 2 CT scans in this study period interpreted by a specific senior attending neuroradiologist. For each patient enrolled, a limited series was generated from the most recent CT scan by selecting four representative axial slices based on the sagittal scout image. These 4 slices where selected at the level of the fourth ventricle, third ventricle, basal ganglia level, and lateral ventricles, respectively. A blinded, senior attending neuroradiologist first reviewed the limited 4-slice CT data set and was asked to determine if the ventricular system had increased, decreased, or remained stable. Subsequently, the neuroradiologist compared their interpretation of the limited examination with the official report from the full CT data set as the standard of reference as well as the interpretation of the most recent prior scan. Results Forty-six patients (age range, 2 months to 18 years; average age, 6.4 years (SD, 4.2), 54% male) were included in the study. Forty-four of 46 (95.7%) limited CT scans matched the official report of the full CT scan. No cases of increased ventricular size were missed (100% positive predictive value for increased ventricular size). The use of a limited head CT (4 axial images) instead of a complete head CT (average of 31 axial images in our studied patients) confers a radiation dose reduction of approximately 87%. Conclusions Our pilot study demonstrates that utilization of limited head CT scan in the evaluation of children with suspected VP shunt malfunction is a feasible strategy for the evaluation of the ventricular size. Further prospective and multidisciplinary studies are needed to evaluate the reliability of limited head CT for the clinical evaluation of VP shunt malfunction.

Current Update on Interstitial Lung Disease of Infancy: New Classification System, Diagnostic Evaluation, Imaging Algorithms, Imaging Findings, and Prognosis.

Childhood interstitial lung disease represents a rare and heterogeneous group of diseases that can result in significant morbidity and mortality, some leading to death during infancy. CT is the imaging test of choice. Although many CT findings are nonspecific and a definitive diagnosis usually cannot be reached by CT alone, the interpreting radiologist is instrumental in defining disease extent and refining the diagnosis. Chest CTs are of key importance in guiding site selection for lung biopsy and for following disease progression and response to treatment. Thus, from the radiologists perspective, ensuring maximal quality of CT imaging and interpretation is paramount.

Advances in Multidetector CT Diagnosis of Pediatric Pulmonary Thromboembolism

Although pediatric pulmonary thromboembolism is historically believed to be rare with relatively little information available in the medical literature regarding its imaging evaluation, it is more common than previously thought. Thus, it is imperative for radiologists to be aware of the most recent advances in its imaging information, particularly multidetector computed tomography (MDCT), the imaging modality of choice in the pediatric population. The overarching goal of this article is to review the most recent updates on MDCT diagnosis of pediatric pulmonary thromboembolism.

The incidental pulmonary nodule in a child

The incidental detection of small lung nodules in children is a vexing consequence of an increased reliance on CT. We present an algorithm for the management of lung nodules detected on CT in children, based on the presence or absence of symptoms, the presence or absence of elements in the clinical history that might explain these nodules, and the imaging characteristics of the nodules (such as attenuation measurements within the nodule). We provide suggestions on how to perform a thoughtfully directed and focused search for clinically occult extrathoracic disease processes (including malignant disease) that may present as an incidentally detected lung nodule on CT. This algorithm emphasizes that because of the lack of definitive information on the natural history of small solid nodules that are truly detected incidentally, their clinical management is highly dependent on the caregivers’ individual risk tolerance. In addition, we present strategies to reduce the prevalence of these incidental findings, by preventing unnecessary chest CT scans or inadvertent inclusion of portions of the lungs in scans of adjacent body parts. Application of these guidelines provides pediatric radiologists with an important opportunity to practice patient-centered and evidence-based medicine.