Differentiating laryngeal carcinomas from precursor lesions by diffusion-weighted magnetic resonance imaging at 3.0 T: a preliminary study.

BACKGROUND: Diffusion-weighted magnetic resonance imaging (DWI) has been introduced in head and neck cancers. Due to limitations in the performance of laryngeal DWI, including the complex anatomical structure of the larynx leading to susceptibility effects, the value of DWI in differentiating benign from malignant laryngeal lesions has largely been ignored. We assessed whether a threshold for the apparent diffusion coefficient (ADC) was useful in differentiating preoperative laryngeal carcinomas from precursor lesions by turbo spin-echo (TSE) DWI and 3.0-T magnetic resonance.

METHODS: We evaluated DWI and the ADC value in 33 pathologically proven laryngeal carcinomas and 17 precancerous lesions.

RESULTS: The sensitivity, specificity, and accuracy were 81.8%, 64.7%, 76.0% by laryngostroboscopy, respectively. The sensitivity, specificity, and accuracy of conventional magnetic resonance imaging were 90.9%, 76.5%, 86.0%, respectively. Qualitative DWI analysis produced sensitivity, specificity, and accuracy values of 100.0, 88.2, and 96.0%, respectively. The ADC values were lower for patients with laryngeal carcinoma (mean 1.195±0.32×10(-3) mm(2)/s) versus those with laryngeal precancerous lesions (mean 1.780±0.32×10(-3) mm(2)/s; P<0.001). ROC analysis showed that the area under the curve was 0.956 and the optimum threshold for the ADC was 1.455×10(-3) mm(2)/s, resulting in a sensitivity of 94.1%, a specificity of 90.9%, and an accuracy of 92.9%.

CONCLUSIONS: Despite some limitations, including the small number of laryngeal carcinomas included, DWI may detect changes in tumor size and shape before they are visible by laryngostroboscopy. The ADC values were lower for patients with laryngeal carcinoma than for those with laryngeal precancerous lesions. The proposed cutoff for the ADC may help distinguish laryngeal carcinomas from laryngeal precancerous lesions.