Advances in Imaging of Ocular and Orbital Tumors in Children

This issue of the Journal of Pediatric Neuroradiology is dedicated to orbital imaging in children.

Each article in the journal will describe common and uncommon imaging features of a variety of orbital disorders in children. Presently, many congenital orbital lesions may be diagnosed prenatally. It certainly makes it necessary for pediatric radiologists and neuroradiologists to be aware of the appearance of these lesions on fetal imaging. Therefore, the first article of this issue demonstrates normal fetal orbital anatomy, describes the growing spectrum of recognizable fetal orbital pathology, and discusses currently available prenatal imaging ([Fig. 1]). Other articles within this issue describe benign and malignant disorders of the orbits, diseases of the globe, and advances in imaging of optic pathway glioma.

Fig. 1. Three-dimensional fetal ultrasound shows normal fetal face with open eyes.

Imaging plays an important role in evaluation of orbital disease. To make the correct diagnosis of orbital lesions may be difficult for several reasons. It may be challenging to obtain in children an accurate history and physical examination. The presenting symptoms (and imaging findings) of different pathologic entities in the orbits may overlap considerably. Nonneoplastic orbital masses may present in a dramatic fashion with visual loss and destructive changes of the orbit, raising concerns for malignancy. At the same time, some malignant tumors of the orbit may closely resemble inflammatory cellulitis both clinically and on imaging. Some of the orbital lesions have a high association with systemic and genetic disorders and, in these cases, represent just the “tip of the iceberg.” Diagnosis of the orbital lesion may prompt diligent search of concurrent lesions elsewhere in the body.

There have been great clinical advancements in treatment of malignant orbital lesions, and therefore, many patients live longer. As a result of the prolongation of the patient's life, several new patterns of progressed/recurrent disease and new types of treatment complications have been revealed.

Orbital imaging made tremendous progress in the last decade as well. New imaging modalities and new applications of existing technologies have been developed and successfully implemented in clinical practice. Proper utilization of primary imaging modalities is discussed in each article: ultrasonography (echography), computed tomography (CT), magnetic resonance imaging, positron emission tomography, and, in select cases, conventional angiography. Furthermore, several emerging and well-established advanced imaging techniques are emphasized where appropriate. Implementation of spiral CT allows for presurgical evaluation of orbital trauma and for navigation of orbital advancement procedures. Previously undetectable minute retinal lesions and small hemorrhages/calcifications have become visible on constructive interference steady state and susceptibility-weighted imaging MR sequences. Arterial spin labeling and diffusion-weighted MR techniques provide quantification of a lesion's perfusion and diffusivity. Recently introduced optical coherence tomography, a noninvasive method based on the utilization of near-infrared light, is remarkable for very good penetration into the tissue and excellent resolution. It is beginning to be applied in the imaging of optic pathway glioma and retinal lesions.

More than one imaging modality may be required for best possible lesion depiction. The radiologist should be familiar with modern orbital imaging modalities and should be able to recommend appropriate testing for the ordering clinician. Whenever possible, a problem-oriented approach, with direct approval and supervision of every study by a radiologist, is important for pediatric radiology in general and for orbital imaging in particular.