Discrimination of the etiology of arytenoid fixation in cT3 laryngeal squamous cell carcinoma (SCC) is crucial for treatment planning. The aim of this retrospective study was to differentiate among possible causes of arytenoid fixation (edema, inflammation, mass effect, or tumor invasion) by analyzing related signal patterns of magnetic resonance (MR) in the posterior laryngeal compartment (PLC) and crico-arytenoid unit (CAU). Seventeen patients affected by cT3 glottic SCC with arytenoid fixation were preoperatively studied by state-of-the-art MR with surface coils. Different signal patterns were assessed in PLC subsites. Three MR signal patterns were identified: A, normal; B, T2 hyperintensity and absence of restriction on diffusion-weighted imaging (DWI); and C, intermediate T2 signal and restriction on DWI. Signal patterns were correlated with the presence or absence of CAU and PLC neoplastic invasion. Patients were submitted to open partial horizontal or total laryngectomy and surgical specimens were analyzed. Pattern A and B did not correlate with neoplastic invasion, while Pattern C strongly did (Spearman's coefficient = 0.779, p < 0.0001; sensitivity: 100%; specificity: 78%). In conclusion, MR with surface coils is able to assess PLC/CAU involvement with satisfactory accuracy. In absence of Pattern C, arytenoid fixation is likely related to mass effect and/or inflammatory reaction and is not associated with neoplastic invasion.
Keywords: cricoarytenoid unit; laryngeal cancer; magnetic resonance imaging; posterior laryngeal compartment; surface coils.