NEOPLASTIC INVASION OF THE LARYNGEAL CARTILAGE - REASSESSMENT OF CRITERIA FOR DIAGNOSIS AT CT

PURPOSE: To evaluate eight different diagnostic criteria to help detec t neoplastic invasion of laryngeal cartilage at computed tomography (C T). MATERIALS AND METHODS: In a prospective series, 111 patients with carcinoma of the larynx or hypopharynx underwent thin-section, contras t material-enhanced CT before total or partial laryngectomy. The follo wing CT criteria were evaluated: extralaryngeal tumor, sclerosis, tumo r adjacent to nonossified cartilage, serpiginous contour, erosion or l ysis, obliteration of marrow space, cartilaginous blowout, and bowing. Histologic findings were correlated with findings on CT scans obtaine d at each level. RESULTS: Histologically, 122 of 412 cartilages were i nvaded. Depending on the diagnostic criteria and each specific cartila ge, there was great variation in sensitivity (7%-83%) and specificity (40%-100%). Sclerosis was the most sensitive criteria in all cartilage s but often corresponded to reactive inflammation in the thyroid carti lage. Extralaryngeal tumor and erosion or lysis yielded the highest sp ecificity. Tumor adjacent to nonossified cartilage, serpiginous contou r, and obliteration of marrow space were specific although not sensiti ve signs of invasion in the arytenoid and cricoid cartilage and were n onspecific in the thyroid cartilage. Blowout and bowing were not usefu l. Selection of the appropriate combination of criteria enabled an ove rall sensitivity of 91% (associated specificity, 68%) or an overall sp ecificity of 79% (associated sensitivity, 82%). CONCLUSION: Detection of neoplastic cartilage invasion with CT greatly depended on the appro priate use of individual and combined CT criteria.