Helical CT scanning of laryngeal deviation

Objective: To evaluate helical computed tomography (CT) scanning in patient s with laryngeal deviation. Materials ann methods: Five patients with laryn geal deviation and three control subjects underwent helical CT. The larynge al deviation was idiopathic in one patient and acquired in four. Three-dime nsional (3D) images of the laryngeal cartilages and bones, 3D airway surfac e models, and sequential coronal and axial images were reconstructed for as sessment. Results: The thyroid cartilage was inclined and twisted to the ri ght in three patients, inclined to the right and twisted to the left in one patient, and inclined to the left and twisted to the right in one patient. The infero-postorior part of the thyroid cartilage, and the cricoid and ar ytenoid cartilages were shifted to the left in four patients. The vocal cor ds were at the level of C-4 similar to C-4/C-5 in two patients, C-4/C-5 m o ne, C-4/C-5 similar to C-5 in one, and C-5 similar to C-5/C-6 in one. In fo ur patients, inclination of the laryngeal cavity to the right may have indu ced left false vocal cord protrusion, The levels of the two false vocal cor ds differed in all patients. When the inclination and twisting were correct ed on the computer, 3D images of the laryngeal cartilages of the patients b ecame almost the same as those of the control subjects? except for slight d eformity of the thyroid cartilage. The width of the right and left thyroid alae was measured on the computer, and was almost equal in all patients. 3D airway surface models of the left hemilarynx resembled those of the right hemilarynx when the angle of view was changed on the computer. Conclusion: Three-dimensional images of the laryngeal cartilages and bones, 3D airway s urface models, and sequential coronal and axial CT scans were obtained usin g helical CT. This method allows the 3D observation of laryngeal deviation, and viewing of images from various directions on the computer was useful t o understand the characteristics of laryngeal deviation. (C) 2001 Elsevier Science ireland Ltd. All rights reserved.