ABSTRACT
BACKGROUND AND OBJECTIVES: Cancer invasion of the laryngeal cartilage is mainly found in the ossified portion of cartilage and contraindication for conservation surgery of laryngopharyngeal cancer. Thus, it is an important factor to consider in planning the management of laryngopharyngeal cancer. Computed tomographic (CT) scan is an useful tool for the evaluation of laryngopharyngeal cancer, but it is difficult to distinguish cancer invasion from non-ossified cartilage regions by the CT scan. Knowledge of the precise ossification pattern will be useful to determine the cancer invasion of laryngeal cartilage. The purposes of this study include ossi6cation pattern according to age, symmetry of ossification and incidence of bone marrow formation. MATERIALS AND METHODS: Fifty-three cases of normal laryngeal CT scans which were reviewed by two radiologists. They were all males, ranging in the ages from 40 to 69 (mean age 53). Ossification degree (%) was measured from the inferior cornu in the thyroid cartilage and the superior border of the posterior lamina in the cricoid cartilage. Age relation and symmetry of ossification and incidence of bone marrow formation were evaluated. RESULTS: There were no correlation between age and degree of laryngeal cartilage ossification (p> 0.05). But there was symmetry and definite pattern of ossification. Symmetry of ossification was 84.9% in the thyroid cartilage. Incidence of bone marrow formation was 60.6% in the thyroid cartilage and 82.8% in the cricoid cartilage. CONCLUSION: This study reveals that there is no ossification-age relationship, but the symmetry and the definite pattern of ossification in the laryngeal cartilage are useful clues in determining the cancer invasion on CT scan.