Diagnosis of laryngeal cartilage invasion by cancer. Comparison of CT and MR imaging

Forty-two patients with laryngeal carcinomas were examined by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). The accuracy of CT and MRI in showing cartilage invasion was evaluated in 16 patients by comparing the results with pathological findings. Calcified cartilage, invaded by cancer, is frequently seen with CT as having an intact contour, whereas tumor approaching non-ossified cartilage may simulate cartilage invasion. On the other hand, T1 weighted MR images demonstrate invaded bone marrow of ossified cartilage with intermediate signal intensity, which allows its differentiation from normal bone marrow. Proton density images show tumor with increased signal intensity, which permits one to differentiate the latter from non-ossified cartilage. In our experience, the specificities of CT and MRI were approximately equal, 91 and 88%, respectively. CT has a definitely lower sensitivity than MRI (46 and 89%, respectively). Gross movement artifacts, which resulted in non-diagnostic images, occurred in 16% of the MRI examinations.