Anatomical Variations in Branching Patterns of Arcus Aorta: 64-slice CTA Appearance

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1 Anatomical Variations in Branching Patterns of Arcus Aorta: 64-slice CTA Appearance Poster No.: C-1012 Congress: ECR 2012 Type: Scientific Exhibit Authors: E. ergun 1, B. simsek 2, P. Kosar 1, B. K. Y#lmaz 1, A. T. Turgut 1 ; 1 2 Ankara/TR, ankara/tr Keywords: DOI: Epidemiology, Venous access, CT-Angiography, Cardiovascular system, Arteries / Aorta /ecr2012/C-1012 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 13

2 Purpose To review the 64-slice CTA appearance of anatomical variations in branching pattern of the arcus aorta and to determine their prevalence in 1001 cases Methods and Materials The reports of 1001 cases who were referred to our radiology department for carotid CTA with various indications over the preceding 5 years ( ) were retrospectively reviewed. CT examinations were performed by a 64-slice CT scanner (Aquillon 64, Toshiba Medical Systems, Japan). The study was approved by intuitional review board. CT Angiography (CTA) protocol: 75 ml contrast media with iodine concentration of # 350 mg/ml was injected through the right antecubital vein. 20-gauge IV cannula was used for venous access. The flow rate of the contrast material was 5 ml/s, followed by a 20 ml saline chaser with the same injection protocol. Optimal scan timing was determined manually by starting the image acquisition as soon as the contrast material was seen in ICA at the level of cervical 1-2 vertebra. Scanning was performed in the cranio-caudal direction, and included the region from arcus aorta inferiorly to Willis polygon superiorly. CT parameters were as follows: section thickness: 3 mm, matrix , FOV: 320 mm, pitch: 0.641, mas: 440,kV: 120. The estimated dose received with this protocol was 8 msv. CT raw data were transformed to a remote work station (Vitrea 2, Vital Images Inc.,Minnetonka, Minn. USA) for further image processing and analysis. Image analysis was performed by a radiologist that is experienced in CTA and all of the examinations were reviewed by the same radiologist. Axial images were reviewed first which was followed by sagittal and coronal reformat images, oblique multiplanar reformate (MPR) images, thick and thin slab maximum intensity projection (MIP) images and volume rendering (VRD) images. Results 1001 patients were included in the study. 519 (51.8%) were male and 482 (48.2%) were female. The age range was years of age (mean: 60.01). In 853 cases (85.2%) arcus aorta had the classical branching pattern (figure 1), in other words variational branching was present in 148 cases (14.8%). The most commonly observed variation, which had a prevalence of 7.8%, was branching of LCCA from BT (figure 2). The second most Page 2 of 13

3 common variation was origination of LVA from arcus aorta which had a prevalence of 5.1% (51 cases) (figure 3,4). Variation in right vertebral artery (RVA) origination was observed in only one case (%0.1) which had RVA that originated from the RCCA and aberrant RSA was also present in the same case (figure 5). In 7 cases (0.7%) truncus brachiocephalicus was absent and RCCA and RSA originated directly from the arch. In 2 cases (0.2%) truncus bicaroticus (common truncus from which RCCA and LCCA originated and RSA originated separately as the first branch of the arch) was present ( figure 6). In one case (0.1%) left TB was present. In 7 (0.7%) cases aberrant right subclavian artery was present (figure 5). One case (0.1%) had right arcus aorta. Images for this section: Page 3 of 13

4 Fig. 1: Figure 1: Shows classical branching pattern of the aortic arc; it has four branches in the order of truncus brachiocephalicus (arrow) (branches to right subclavian artery Page 4 of 13

5 (double arrows)and right common carotid artery (open arrow)), left common carotid artery (curved arrow) and left subclavian artery (asterisk). Page 5 of 13

6 Fig. 2: VRD image depict the most common variant which was observed in the present study; bovine arch, which has two branches, and left common carotid artery ( open arrow) arises from the truncus brachiocephalicus (solid arrow). Page 6 of 13

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8 Fig. 4: MIP image show Left vertebral artery originating directly from the aortic arc as its last branch, distal to left subclavian artery. Fig. 3: VRD image shows Left Vertebral artery originating directly from the aortic arc as its last branch, distal to LSA. Page 8 of 13

9 Fig. 5: VRD image. Aberrant right subclavian artery which originates from the aortic arc as its last branch distal to left subclavian artery is seen. Left common carotid artery from which right vertebral artery arises is the first branch of the aortic arc. Page 9 of 13

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11 Fig. 6: VRD image shows an aortic arc with three branches. Left arrow) and right common carotid arteries arise from a common truncus. Page 11 of 13

12 Conclusion In the classical anatomical configuration arcus aorta is left sided and has 3 branches in the order of truncus brachiocephalicus (BT) (branches in to right common carotid artery (RCCA) and right subclavian artery (RSA)), left common carotid artery (LCCA) and left subclavian artery (LSA). Approximately in % of the individuals aortic arch have this standard anatomical configuration (1,2,3). Variations in branching pattern of arcus aorta which has an incidence of 14.8% in the present study is common. Most of them have no clinical importance however they should be known because anatomic features of the aortic arch is important for vascular surgeons, interventional radiologists and head and neck surgeons. Multislice CTA depicts the arch anatomy precisely and can be a road map before the interventional procedures and surgeries of the head and neck region. References References: 1- Jakanani GC, Adair W. (2010) Frequency of variations in aortic arch anatomy depicted on multidetector CT. Clinical Radiology 65: Shiva Kumar G L, Pamidi N, Somayaji S N, Nayak S, Vollala V R. (2010) Anomalous branching pattern of the aortic arch and its clinical applications. Singapore Med J 51(11) : e182 3-Natsis KI, Tsitouridis IA, Didagelos MV, Fillipidis AA, Vlasis KG, Tsikaras PD.(2009) Anatomical variations in the branches of the human aortic arch in 633 angiographies: clinical signiwcance and literature review. Surg Radiol Anat 31:319- Personal Information Dr. Elif Ergun Instructor in Radiology Department of Radiology, Ankara Training and Research Hospital, Page 12 of 13

13 Address: Ankara E#itim ve Arast#rma Hastanesi, Radyoloji Bölümü, TR-06590, Ulucanlar, Ankara, Turkey Phone: ; fax: Page 13 of 13