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Pediatr Radiol (2009) 39 (Suppl 2):S184S190 DOI 10.1007/s00247-008-1108-2
REVIEW
Evaluation of non-vascular mediastinal masses in infants and children: an evidence-based practical approach
Edward Y. Lee
# Springer-Verlag 2008
Keywords Non-vascular mediastinal masses . Imaging evaluation . Practical approach . Pediatric patients
Introduction
The mediastinum is the most common location of nonvascular chest masses in infants and children. For evaluation of non-vascular mediastinal masses in infants and children, imaging plays an important role in early, correct diagnosis and optimal patient management. Therefore, a practical imaging approach based on the most sensitive and least invasive imaging modality in an efficient and cost-effective way is paramount. The objective of this presentation is to review the use of currently available imaging modalities (chest radiographs, ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography) in evaluating non-vascular mediastinal masses in infants and children. The emphasis is on an evidence-based practical diagnostic imaging approach.
Definition and pathophysiology of non-vascular mediastinal masses
The mediastinum is anatomically defined as the portion of the thorax between the pleural spaces bounded by the sternum anteriorly, the vertebral column posteriorly, the
thoracic inlet superiorly, and the diaphragm inferiorly [19]. Except for the lungs, the mediastinum contains all of the structures within the thorax including the thymus gland, the thoracic portion of the trachea and esophagus, the great vessels, the heart, lymph nodes, fat, and nerves. Non-vascular mediastinal masses can arise from each of these diverse intrathoracic structures except the great vessels, representing a wide spectrum of conditions including congenital anomalies, benign and malignant neoplasms, and infection [19].
The goals of diagnostic imaging in evaluating non-vascular mediastinal masses
Understanding the characteristic imaging features of nonvascular mediastinal masses and knowing which imaging modality (based on sensitivity, specificity, and accuracy) to reach the most definitive diagnosis are paramount in evaluating non-vascular masses in the pediatric population. The four major goals of diagnostic imaging in evaluating non-vascular mediastinal masses in infants and children include: (1) identifying the mass and localizing it within the mediastinum; (2) characterizing the mass and delineating its extent; (3) providing appropriate differential diagnostic considerations and most likely diagnosis; and (4) generating a plan for the most cost-effective and non-invasive further imaging studies/patient management.
Available imaging modalities
Chest radiographs (CXR)
Two radiographs (frontal and lateral views)...