Computerized axial tomography in the assessment of thyroid cartilage invasion by laryngeal carcinoma: a prospective study.

The purpose of this study was to assess the value of computerized axial tomography (CAT) in canine larynges that exhibit controlled surgical defects, and in 18 patients with biopsy-proved epidermoid carcinoma of the larynx who were studied prospectively. Five canine larynges with sequential surgical defects of 0 mm, 5 mm, 10 mm, and 15 mm were studied by CAT in order to evaluate our ability to identify defects in the thyroid cartilage. A 5-mm collimator with overlapping sections at 3-mm intervals and a 13-mm collimator with 5-mm overlapping sections were both used for each stage of the experiment. Results show significantly improved resolution with the 5-mm collimator compared with the 13-mm unit. In the human study group, results demonstrated excellent (100%) soft-tissue tumor site correlation. It appears from this study that we still lack a highly reliable radiographic technique for evaluating preoperatively with accuracy the integrity of the thyroid cartilage in the patient with carcinoma of the larynx.