cancers Article Prediction of Posterior Paraglottic Space and Cricoarytenoid Unit Involvement in Endoscopically T3 Glottic Cancer with Arytenoid Fixation by Magnetic Resonance with Surface Coils Marco Ravanelli 1 , Alberto Paderno 2,*, Francesca Del Bon 2, Nausica Montalto 2, Carlotta Pessina 1, Simonetta Battocchio 3, Davide Farina 1, Piero Nicolai 2, Roberto Maroldi 1 and Cesare Piazza 4 1 Department of Radiology, University of Brescia, 25123 Brescia, Italy; [email protected] (M.R.); [email protected] (C.P.); [email protected] (D.F.); [email protected] (R.M.) 2 Department of Otorhinolaryngology—Head and Neck Surgery, University of Brescia, 25123 Brescia, Italy; [email protected] (F.D.B.); [email protected] (N.M.); [email protected] (P.N.) 3 Department of Pathology, University of Brescia, 25123 Brescia, Italy; [email protected] 4 Department of Otorhinolaryngology, Maxillofacial, and Thyroid Surgery, Fondazione IRCCS, Istituto Nazionale dei Tumori di Milano, University of Milan, 20133 Milan, Italy; [email protected] * Correspondence: [email protected] Received: 7 December 2018; Accepted: 4 January 2019; Published: 10 January 2019 Abstract: 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: laryngeal cancer; magnetic resonance imaging; surface coils; posterior laryngeal compartment; cricoarytenoid unit 1. Introduction Endoscopic evaluation represents a paramount diagnostic and staging tool for the assessment of laryngeal tumors. Vocal fold (i.e., arytenoid) fixation in glottic squamous cell carcinoma (SCC) leads to classification in the cT3 category according to the 7th Edition of the AJCC UICC TNM staging system (unchanged in the subsequent 8th Edition) [1,2]. This clinical sign has recently been better defined by Rosen et al. [3] as “vocal fold immobility related to laryngeal malignant disease”. However, such a clinical diagnosis may either underestimate the true neoplastic extent (e.g., pT4 with clinically Cancers 2019, 11, 67; doi:10.3390/cancers11010067 www.mdpi.com/journal/cancers Cancers 20192019,, 1111,, 67x 2 of 1112 with clinically silent cartilage invasion or extralaryngeal spread) or overestimate it (e.g. in “simple” silentpT2 when cartilage the invasioncricoarytenoid or extralaryngeal unit (CAU) spread)is only orimpaired overestimate in its itnormal (e.g., in function “simple” by pT2 peritumoral when the cricoarytenoidedema or tumor unit bulk (CAU) rather is only than impaired by true in itsneopla normalstic function infiltration). by peritumoral On the other edema hand, or tumor from bulk an ratheretiopathological than by true point neoplastic of view, infiltration). vocal fold/aryteno On the otherid immobility hand, from ancan etiopathological be related to pointa number of view, of vocaldifferent fold/arytenoid factors: invasion immobility of the can CAU, be related intrinsic to alaryngeal number ofmuscle different involvement, factors: invasion infiltration of the of CAU, the intrinsicintra- and/or laryngeal extralaryngeal muscle involvement, nerve supply, infiltration volume of (mass) the intra- effect, and/or and inflammatory extralaryngeal changes. nerve supply, This volumeleads to (mass) substantial effect, anddiagnostic inflammatory uncertainty, changes. sinc Thise these leads conditions to substantial have diagnostic relevant uncertainty, and dissimilar since theseclinical conditions implications. have relevantFor example, and dissimilar in a recently clinical implications.published multicentric For example, study in a recently on T3 published and T4 multicentriclaryngeal SCC study treated on T3 by and open T4 laryngealpartial horizont SCC treatedal laryngectomies by open partial (OPHLs), horizontal pT3 laryngectomies tumors with (OPHLs),posterior laryngeal pT3 tumors compartment with posterior (PLC) laryngeal invasion compartment (i.e. the paraglottic (PLC) invasion space located (i.e., the posterior paraglottic to spacea line locateddrawn from posterior the arytenoid to a line vocal drawn process from the perpendicu arytenoidlarly vocal to the process thyroid perpendicularly cartilage, of which to the the thyroid CAU cartilage,represents of a whichkey structure) the CAU demonstrated represents a key signific structure)antly worse demonstrated prognosis significantly than anteriorly worse located prognosis pT4 thanlesions anteriorly [4]. For locatedthis reason, pT4 lesionsthe theoretical [4]. For thisplane reason, dividing the theoreticalthe anterior plane from dividing the PLC the was anterior also called from theby the PLC authors was also the called “magic by plane” the authors (Figure the 1). “magic plane” (Figure1). Figure 1.1.Anatomical Anatomical section section representing representing the the glottic glottic plane plane on a transverseon a transverse section: section: dashed linedashed (“magic line plane”(“magic according plane” according to Succo etto al. Succo [4]) indicateset al. [4] the) indicates limit dividing the limit the dividing anterior (green)the anterior from (green) the posterior from (red)the posterior laryngeal (red) compartments. laryngeal comp Legend:artments. Ac, arytenoid Legend: cartilage; Ac, arytenoid tc, thyroid cartilage; cartilage; tc, vm,thyroid vocal cartilage; muscle. vm, vocal muscle. Imaging has the ability to accurately delineate submucosal tumor extension in order to elucidate the causeImaging of arytenoid has the hypomotilityability to accurately or fixation. delineate In particular, submucosal we have definedtumor extension as “arytenoid in order fixation” to theelucidate complete the immobilitycause of arytenoid of both thehypomotility vocal fold andor fixation. arytenoid In cartilage particular, [3]. we Magnetic have defined resonance as (MR)“arytenoid offers fixation” higher contrast the complete resolution immobility than computed of both tomography the vocal fold (CT) and and arytenoid is particularly cartilage helpful [3]. inMagnetic distinguishing resonance tumor (MR) infiltrationoffers higher from contrast peritumoral resolution inflammation, than computed and tomography in depicting (CT) cartilage and is infiltrationparticularly [5helpful]. State in of distinguishing the art protocols, tumor including infiltration use offrom surface peritumoral coils, enhance inflammation, the potential and ofin thedepicting technique cartilage by significantly infiltration increasing [5]. State of its the spatial art protocols, resolution. including use of surface coils, enhance the potentialThe aim of of the this technique study was by tosignificantly explore the increasing capability its of spatial MR in resolution. assessing the PLC, with special emphasisThe aim given of this to evaluationstudy was ofto CAU,explore in the clinically-defined capability of MR T3 in SCCassessing with the arytenoid PLC, with fixation special at preoperativeemphasis given endoscopic to evaluation evaluation. of CAU, in clinically-defined T3 SCC with arytenoid fixation at preoperative endoscopic evaluation. 2. Materials and Methods 2. Materials and Methods 2.1. Patient Selection 2.1. PatientThe present Selection retrospective study was performed in a tertiary academic center. It included 17 patients (13 males and four females: mean age, 65 years; age range, 48–82) with histologically The present retrospective study was performed in a tertiary academic center. It included 17 patients (13 males and four females: mean age, 65 years; age range, 48–82) with histologically Cancers 2019, 11, 67 3 of 11 Cancers 2019, 11, x 3 of 12 demonstrated glottic SCC defined as cT3 for arytenoid fixation via transnasal flexible videoendoscopy. demonstrated glottic SCC defined as cT3 for arytenoid fixation via transnasal flexible This is a purely retrospective study with no need to receive approval from ethics committee, and no videoendoscopy. This is a purely retrospective study with no need to receive approval from ethics informed consent was signed. Each examination was video-recorded and separately re-evaluated committee, and no informed consent was signed. Each examination was video-recorded and byseparately two experienced re-evaluated laryngologists/head by two