Role of multislice ct and local contrast in diagnosis and characterization of choanal atresia

Choanal atresia is defined as a pathological closure or absence of the posterior nasal choana, it may be unilateral or bilateral It is the most common nasal abnormality in the new born. In case of bilateral choanal atresia, when the infant has his mouth closed, he. can not inspire and becomes cyanotic. Unilateral atresia is usually discovered at 1 to 2 year old child with unilateral copious mucoid rhinorrhea. Computerized tomography is now the method of choice in the evaluation of congenital choanal atresia. Both coronal and axial cuts are needed in determining whether the disease is unilateral or bilateral, and the approximate thickness of the bone. The knowledge of abnormal anatomy is vital in preoperative planning and help with choice of surgical technique. This study aims to illustrate the potential value of multislice CT with nasal local contrast administration in the diagnosis and characterization of the detailed anatomical abnormality of Choanal atresia without the need for direct coronal CT. Seventeen patients were examined [ten females and seven males]. The youngest was 1 day neonate and the oldest was 6 year old child. All patients were referred for evaluation of nasal obstruction and to exclude clinically suspected Choanal atresia. The child or neonate was prepared in supine position and axial multislice CT study was done. The examinations were done with a pilch of 2.5 mm, reconstruction of 1.25 mm interval and no gantry tilt. Three drops of half diluted non-ionic contrast was dropped into each nostril just prior to the examination. Reconstruction in saggittal and oblique coronal was done till the posterior choana were seen clearly in all patients with different reformatting angles. The maxillary spines were considered as a mark to the inferior margin of the posterior choana. Posteroinferior vomer width was measured. It was considered thickened when it exceeds 5.5 mm. [12]. All surgical cases were managed by using fibrop