Leukocoria in Children: Findings on CT and MRI of the Principal Causes
Leukocoria is the result of an alteration in the normal red reflex of the ocular fundus, secondary to an obstruction of the normal passage of light to the fundus of the eye that produces a white light reflex. There are many ocular pathologies that can present as leukocoria, among which retinoblastoma is the most frequent. Other causes include cataracts, Coats disease, persistent fetal vasculature, coloboma, retinopathy of prematurity, vitreous hemorrhage, astrocytic hamartoma, and ocular toxocariasis. Although in many situations the diagnosis of these pathologies is clinical or possible with the use of ocular sonography, in certain circumstances, CT or MR imaging may play a very important role in the differential diagnosis. In this review article, we propose that findings such as ocular size, the presence of calcifications, intravenous contrast enhancement, MR imaging signal intensity, CT density, and other pathology-specific findings, along with some clinical data, will guide us to the cause of leukocoria. Knowledge of the most prevalent ages of presentation of these pathologies assists with establishing the final diagnosis. Learning Objectives: To understand why leukocoria occurs, to list the major causes of leukocoria in children, and to recognize the imaging findings of the most frequent causes of leukocoria and apply them in the differential diagnosis.
