In Vivo Computed Tomography Direct Volume Rendering of the Anterior Ethmoidal Artery: A Descriptive Anatomical Study

THIEME e38 Original Research In Vivo Computed Tomography Direct Volume Rendering of the Anterior Ethmoidal Artery: A Descriptive Anatomical Study Filippo Cascio1 Alberto Cacciola2 Simona Portaro3 Gianpaolo Antonio Basile2 Giuseppina Rizzo2  Wady Debes Felippu4 Alexandre Wady Debes Felippu4 Antongiulio Bruschetta2 Andre Carmelo Anfuso3 Felice Cascio1 Demetrio Milardi2,3 Alessia Bramanti3 1 Department of Otorhinolaryngology, Papardo Piemonte Reunited Hospitals, Messina, Sicilia, Italy 2 Department of Biomedical, Odontoiatric, Morphological and Functional Imaging Sciences, Università degli Studi di Messina, Messina, Italy 3 Scientific Institute for Research, Hospitalization and Health Care Centro Neurolesi Bonino Pulejo, Messina, Italy 4 Department of Otorhinolaryngology, Instituto Felippu, São Paulo, Brazil Address for correspondence Prof. Demetrio Milardi, Department of Biomedical, Dental Sciences and Morphological and Functional Images, Univeristy of Messina, Messina, Italy (e-mail: ). Int Arch Otorhinolaryngol 2020;24(1):e38–e46. Abstract Keywords ► anterior ethmoidal artery ► CT ► volume rendering Introduction The clinical relevance of the anatomy and variations of the anterior ethmoidal artery (AEA) is outstanding, considering its role as a landmark in endoscopic surgery, its importance in the therapy of epistaxis, and the high risks related to iatrogenic injuries. Objective To provide an anatomical description of the course and relationships of the AEA, based on direct computed-tomography (CT)-based 3D volume rendering. Methods Direct volume rendering was performed on 18 subjects who underwent (CT) with contrast medium for suspected cerebral aneurism. Results The topographical location of 36 AEAs was assessed as shown: 10 dehiscent (27.8%), 20 intracanal (55.5%), 6 incomplete canals (16.7%). Distances from important topographic landmarks are reported. Conclusion This work demonstrates that direct 3D volume rendering is a valid imaging technique for a detailed description of the anterior ethmoidal artery thus representing a useful tool for head pre-operatory assessments. Introduction The anterior ethmoidal artery (AEA), a branch of the ophthalmic artery, crosses three cavities along its course: it arises in the orbit, reaches the ethmoidal labyrinth passing through the bony anterior ethmoidal canal (AEC) together with its homonymous vein and nerve, and finally enters the olfactory fossa, through the lateral lamella of the cribriform plate, along the so-called anterior ethmoidal sulcus,1 where it becomes the anterior falx artery2. received October 25, 2018 accepted August 18, 2019 DOI https://doi.org/ 10.1055/s-0039-1698776. ISSN 1809-9777. Several studies demonstrated that the AEC is not always continuous in its bony structure, but it may show a partial or complete bone dehiscence in its most caudal portion.1,3,4 Significant intrasubject side-to-side variability may exist so that the bony canal can be complete on one side and partially or completely open on the other one. Moreover, useful information about the distance of the AEA from the columella,5 the middle turbinate axilla and the nasal valve1,6 has been provided. Copyright © 2020 by Thieme Revinter Publicações Ltda, Rio de Janeiro, Brazil Volume Rendering of Anterior Ethmoidal Artery The AEA is one of the most important landmarks in endoscopic surgery, representing a fundamental orientation point for ethmoidal fovea and anterior cranial fossa.7,8 In the surgical approach to the frontal recess, the AEC marks its posterior border.9,10 Likewise, in the external approaches, AEA identification in the fronto-ethmoidal suture marks the ventral limit of the anterior cranial fossa.11 In addition to the marking function, the AEA, together with the arteries coming out from the sphenopalatine foramen, plays a key role for vascular ligation in nasal surgery to control epistaxis during endoscopic sinus surgery (ESS).12,13 Considering the huge variety of its anatomical localization, course, and length, the preoperative assessment of AEA is of clinical relevance. Indeed, severe iatrogenic injuries may lead to liquor fistulas, intracranial bleeding and blindness, if not decompressed within an hour.14 As shown by Cassano et al,12 if a good hemostatic control is performed under endoscopic view during the nasal surgery, the nasal precautionary intraoperative packing is not justifiable, considering the low percentage of postoperative epistaxis. Furthermore, ligation of the sphenopalatine complex and of the AEA is a good way to gain control of epistaxis.15 The application of preoperative imaging techniques allows to obtain information about the development of the paranasal sinuses, variants of pneumatization, as well as anatomical variants of the vessels in relation to the adjacent rhino-ethmoidal structures, thus allowing accurate surgical planning and increasing safety in rhino-sinusal endoscopic surgical procedures.16–18 During the last decades, the development of many postprocessing techniques and the modulation of the image presets have allowed for subject- and condition-based interpretations of magnetic resonance imaging (MRI),19–41 ultrasonography42 and computed tomography (CT) data,43–45 thus providing the real 3D morphology of several structures and better highlighting anatomical details. In this regard, the direct volume rendering (DVR) is a direct technique to visualize primitive volumes without any intermediate conversion of the volume data to surface presentation.46 However, despite its clinical usefulness, to the best of our knowledge, only a few 3D-reconstruction studies have demonstrated the course of the AEA and its relationship with the skull base and adjacent structures through non-invasive imaging in living human subjects.47,48 Based on these simple premises, the present work is aimed at i) visualizing topographic anatomical details, such as the AEA course and its relations with the skull base; ii) understanding whether preoperative detailed information on the course of the AEA in its AEC or its possible dehiscence can be achieved noninvasively and on living human subjects by direct volume rendering (DVR) on multidetector computed tomography (MDCT) with contrast medium of supra aortic trunks (SAT). Materials and Methods Participants We retrospectively evaluated 18 patients, 10 of whom were male and 8 female, aged between 28 and 82 years old Cascio et al. (63.4
17.9), who underwent MDCT of the SAT because of suspected cerebral aneurism between the 2015 and 2016. Data Acquisition In all patients, MDCT of the cranium was performed by a 64banks multislice CT scanner Philips MX-8000 EXP v25 model (Philips Medical Systems, New Hartford, CT, USA) with axial volumetric acquisition and with transfemoral infusion of contrast medium (iopromide) at a dose of 120 mg/ml. We evaluated the lengths and distances between the AEA at its entry point in the nasal cavity and the skull base, the middle portion of th (...truncated)