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Findings: Axial CT images through the region of the hard palate demonstrate bilateral choanal atresia.
Diagnosis: Choanal atresia.
Discussion: The ectoderm which forms the cranium is separated from the stomodeum by a mesenchymal plate. During the seventh week of embryologic development this plate normally perforates. Failure to do so results in choanal atresia. The atresia may be unilateral or bilateral, and approximately 75% are associated with other congenital anomalies. Most atresias are at least partly bony, but approximately 5% are entirely membranous.
Due to the newborn infant naturally being a nasal breather, choanal atresia results in severe respiratory distress in the neonate. This diagnosis is suspected when a catheter will not pass to the oropharynx. CT is the diagnostic modality of choice, with which either membranous or the more common bony atresia is easily diagnosed.
References:
Valvassori G. Imaging of the Head and Neck. Thieme
Medical Publishers, Inc. New York. 1995;272-274.
Harnsberger, R. Head and Neck Imaging. Year Book Medical
Publishers, Inc. Chicago 1990;397-398.
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