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Amazing anatomy: roadmaps of venous collateral circulation in patients with SVC obstruction. Poster No.: C-1962 Congress: ECR 2011 Type: Educational Exhibit Authors: G. Staskiewicz , E. Czekajska-Chehab , S. Uhlig , K. Torres , A. 1 2 2 2 2 1 2 2 2 Torres , R. Maciejewski , A. Drop ; LUBLIN/PL, Lublin/PL Keywords: Anatomy, Cardiovascular system, CT-Angiography, Diagnostic procedure, Education, Obstruction / Occlusion, Embolism / Thrombosis DOI: 10.1594/ecr2011/C-1962 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. www.myESR.org Page 1 of 19 Learning objectives To review the anatomical background of collateral venous communications in patients with SVC obstruction. To analyze patterns of MDCT presentation of collateral vessels; to remember and recall the main anatomical variants of thoracic veins. To provide images of rare CT presentations of venous collaterals. Images for this section: Page 2 of 19 Fig. 1 Page 3 of 19 Background Collateral circulation plays important role in patients with obstruction of SVC, which may result from multiple benign, malignant or iatrogenic conditions. The purpose of the presentation is to review the most important pathways of collateral circulation in patients with obstruction of SVC, as well as to provide tips for easy identification. Four main systems of collateral venous circulation include: (1) azygos system of veins, which provides communication between SVC and ascending lumbar vein; (2) subfascial system of epigastric veins, which provide collateral circulation between brachiocephalic vein and external femoral vein; (3) subcutaneous system of superficial epigastric vein; (4) vertebral veins. Less frequent variants include systemic-pulmonary or intramuscular pathways. Images for this section: Page 4 of 19 Fig. 1 Page 5 of 19 Imaging findings OR Procedure details Azygos system of veins provides communication between SVC and ascending lumbar veins, which receive lumbar veins, forming anastomosis with IVC. Azygos system consists of veins of posterior wall of the trunk, which receive multiple tributaries, particularly within their course through the mediastinum (Figure 1 on page , Figure 2 on page 8). Azygos system forms the best developed anastomosis between vena cava systems, with its tributaries arising from both parietal, as well as visceral (in particular mediastinal and bronchial - Figure 3 on page 8) veins. Subcutaneous veins of the trunk form the anastomosis between axillary vein and femoral vein (Figure 4 on page 9). Superficial system anastomoses with the subfascial system by means of perforating veins, which carry blood from medial aspect of breasts (Figure 5 on page 10) and sternal branches of internal thoracic veins. Subfascial system of veins connects external iliac vein and subclavian vein by means of internal thoracic and inferior epigastric veins. Internal thoracic veins (ITV) are tributaries of brachiocephalic veins. They are formed by junction of musculophrenic veins (Figure 6 on page 11) and superior epigastric veins. Internal thoracic veins anastomose at the posterior surface of sternum (Figure 7 on page 12). Parietal tributaries of ITV are anterior intercostal veins (Figure 8 on page 13), which provide anastomosis with the azygos sysem, by means of posterior intercostals. Additional tributaries of brachiocephalic veins, frequently widened in patients with SVC syndrome, are pericardiophrenic veins (Figure 9 on page 14). Relations of superficial and inferior epigastric veins and their junctions with femoral and external iliac veins are presented at Figure 10 on page 15. Vertebral plexuses form two vascular rings, located outside the vertebrae: anterior and posterior external vertebral plexus, as well as inner, internal vertebral plexuses located within the vertebral canal (Figure 11 on page 16, Figure 12 on page 17). In the cervical region, anterior external plexus anastomoses with vertebral veins, in thoracic region with posterior intercostal veins, in lumar - lumbar veins. At the anterior aspect of sacral bone it anastomoses with median and lateral sacral veins. Posterior external plexus is best developed in the cervical region, anastomosing with occipital, vertebral and deep cervical veins. Images for this section: Page 6 of 19 Page 7 of 19 Fig. 1: Azygos system of veins. Multiple anastomoses of this system include parietal veins (lumbar, ascending lumbar, intercostal, @-superior phrenic) as well as visceral (#renal, *- mediastinal, including: bronchial, esopahgeal, pericardiac) veins Fig. 2: Widening of azygos sytem of veins in a patient with left-sided SVC syndrome. Page 8 of 19 Fig. 3: BV - bronchial veins. Page 9 of 19 Fig. 4: Superficial (R) and subfascial (L) systems of veins. Superifical veins: Superificial EV - superficial epifastric vein, TEV - thoracoepigastric veins, CAV - costoaxillary veins, LTV - lateral thoracic vein, AP - areolar plexus. ST - sternal branches of internal thoracic vein, Perf - perforating branches. Page 10 of 19 Fig. 5: Perforating branch - tributary of internal thoracic vein. Page 11 of 19 Fig. 6: MPV - musculophrenic vein. Page 12 of 19 Fig. 7: Retrosternal anastomoses of internal thoracic veins. Page 13 of 19 Fig. 8: LTV - lateral thoracic vein, AIcV - anterior intercostal vein, ITV - internal thoracic vein. Page 14 of 19 Fig. 9: PCPV - pericadriophrenic vein, MV- mediastinal veins. Page 15 of 19 Fig. 10: Veins of anterior abdominal wall. Page 16 of 19 Fig. 11: AI - anterior internal plexus, PI - posterior internal plexus. AE - anterior external plexus, PE - posterior external plexus, BVV - basivertebral vein, VV - vertebral vein, DCV - deep cervical vein. Page 17 of 19 Fig. 12: Vertebral plexus in cervical region. Page 18 of 19 Conclusion MDCT allows detailed visualization of anatomical structures important in patients with SVC obstruction. Appropriate knowledge of its anatomy and common anatomical variants is essential for proper identification of abnormal conditions. Postprocessing methods are extremely useful in explaining the complex anatomy of small thoracic veins, especially for in-training readers, however, proper training allows quick identification of anatomy on axial scans. Personal Information Grzegorz Staskiewicz, MD, PhD Medical University of Lublin, I Department of Radiology Jaczewskiego 8, 20-079 Lublin, Poland [email protected] References 1. 2. 3. 4. Cihangiroglu M, Lin BH, Dachman AH.Collateral pathways in superior vena caval obstruction as seen on CT. J Comput Assist Tomogr. 2001 JanFeb;25(1):1-8. Kapur S, Paik E, Rezaei A, Vu DN. Where there is blood, there is a way: unusual collateral vessels in superior and inferior vena cava obstruction. Radiographics. 2010 Jan;30(1):67-78. Moore KL, Dalley AF, Agur AM. Clinically Oriented Anatomy, LWW, 2009 Netter FH. Atlas of Human Anatomy, Saunders, 2010. Page 19 of 19