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Collateral pathways of the abdominal wall: anatomical review and pathologic findings at 64-slice multidetector CT angiography Poster No.: C-3062 Congress: ECR 2010 Type: Educational Exhibit Topic: Vascular Authors: L. Miranda Orella, J. M. Mellado Santos, N. Yanguas Barea, S. Solanas Álava, R. Larrosa Lopez, J. Martín Cuartero; Tudela/ES Keywords: collateral pathways, abdominal wall, multidector CT 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 30 Learning objectives • • To review the anatomy and variability of normal arteries and veins of the abdominal wall. To illustrate and discuss the arterial and venous collateral pathways of the abdominal wall, as seen on 64-slice multidetector CT angiography. Background Collateral circulation of the abdominal wall is common in various vascular disorders. Although scant mention of the topic is found in the radiologic literature, these collateral pathways are clinically relevant, and may be characterized by multidetector CT angiography. TECHNICAL ASPECTS Currently available MDCT offers the combined advantages of high speed, seamless coverage of the entire abdomen, and outstanding spatial resolution, owing to available isometric submillimeter voxel size. These technical advances have significantly improved image quality of CT-angiographic studies, where a number of injection protocols may be selected for adequate depiction of arteries or veins. Page 2 of 30 In addition, state-of-the-art MDCT equipment incorporates improved tridimensional displays, including multiplanar reformations, maximum-intensity projections (MIP) and coloured volume-renderings, which greatly contribute to the study of the small-caliber vessels of the abdominal wall. Imaging findings OR Procedure details ANATOMICAL REVIEW Summed anatomical review of the most important arteries and veins of the abdominal wall is enclosed in the tables below. Arteries of the abdominal wall Artery Source Anastomoses Inferior intercostal Descending thoracic aorta Superior and inferior epigastric, deep circumflex arteries Superior epigastric Internal mammary a. Inferior epigastric and intercostal arteries Inferior epigastric External iliac a. Superior epigastric, intercostal arteries. Deep circunflex iliac External iliac a. Inferior intercostal and lumbar arteries Subcostal and lumbar Abdominal aorta Deep iliac circumflex, inferior gluteal arteries Veins of the abdominal wall Page 3 of 30 Vein Drains to Main anastomoses Superior epigastric Internal mammary v. Inferior epigastric v. Inferior epigastric External iliac v. Superior epigastric v. Thoracoepigastric Lateral thoracic v. Superficial circumflex v. Superficial epigastric Internal saphena v. Tributaries of paraumbilical veins and thoracoepigastric v. Paraumbililical Left branch of portal v. Inferior cava, superior and inferior epigastric veins, superficial epigastric v. Superficial circumflex Internal saphena v. Thoracoepigastric v. ARTERIAL COLLATERAL PATHWAYS PATHOLOGIC CONDITIONS OF THE ABDOMINAL WALL IN Arterial collateral circulation is mainly found in chronic aortic and aortoiliac occlusive disease: • When the stenosis occurs in the descending thoracic aorta, internal mammary arteries connect subclavian arteries with the descending thoracic aorta through the intercostal arteries and with the external iliac arteries through the superior and inferior abdominal epigastric arteries. Page 4 of 30 Fig.: Diagram 1. References: Hospital of Tudela • If stenosis affects the suprarenal aorta, intercostal arteries may anastomose the external iliac arteries through the superior and inferior epigastric arteries or through the deep iliac circumflex arteries. Page 5 of 30 Fig.: Diagram 2. References: Hospital of Tudela • In infrarenal aorta and aortoiliac occlusion other collateral pathways are possible: the lumbar arteries may supply the internal iliac arteries via the inferior gluteal arteries or connect with external iliac arteries via the circumflex arteries (Fig 1 on page 15, fig 2 on page 16, fig 3 on page 16). Page 6 of 30 Fig.: Diagram 3. References: Hospital of Tudela VENOUS COLLATERAL PATHWAYS OF THE ABDOMINAL WALL IN PATHOLOGIC CONDITIONS Page 7 of 30 Venous collateral circulation associates with superior vena cava obstruction, inferior vena cava occlusion, and portal hypertension: Superior vena cava stenosis is usually compensated by collateral circulation through the azygos-hemiazygos system. Only when azygos vein is also occluded abdominal wall collateral pathways are seen. Three routes are possible: • Deep route: Brachiocephalic v. # internal mammary # superior epigastric v. # inferior epigastric v. # external iliac v. (Fig 4 on page 17, fig 5 on page 18) Page 8 of 30 Fig.: Diagram 4 References: Hospital of Tudela • Superficial routes (Fig 5 on page 18, fig 6 on page 19, fig 7 on page 20, fig 8 on page 21, fig 9 on page 22): - Lateral route: Subclavian v. # lateral thoracic v. # thoracoepigastric v. # superficial circumflex iliac v. # internal saphena v. - Medial route: Internal mammary v. # superficial tributaries of internal mammary v. # superficial tributaries of paraumbilical v. # superficial epigastric v. # internal saphena v. Fig.: Diagram 5. References: Hospital of Tudela • Portal system: Small vessels from superior, inferior and superficial epigastric veins can anastomose with paraumbilical v. and portal system (Fig 4 on page 17, fig 5 on page 18, fig 6 on page 19). Page 9 of 30 Fig.: Diagram 6. References: Hospital of Tudela With the Inferior vena cava obstruction (Fig 10 on page 23) can appear four major collateral pathways through which blood returns from lower extremities and pelvis but only the two last ones involve the abdominal wall: • Deep pathway: azygos-hemiazygos system. • Intermediate pathway: gonadal and periureteric vessels. • Abdominal wall pathways: Similar to those described for SVC occlusion but with inverse blood flow. • Portal pathways: Page 10 of 30 - Mesenteric pathway: Internal iliac v. # hemorroidal plexus # inferior mesenteric v. # splenoportal axis. - Superficial pathway: Epigastric vv. # paraumbilical v. # portal system. Collateral circulation of the abdominal wall may also be caused by portal hypertension, usually following the course of the paraumbilical veins. Page 11 of 30 Fig.: Diagram 7. References: Hospital of Tudela Paraumbilical vein arise from the left portal vein and may anastomose with: • Superior epigastric or internal mammary veins and drain into the superior vena cava (Fig 11 on page 24) • Inferior and superficial epigastric vein and drain into the external iliac and internal saphena veins respectively. (Fig 12 on page 25, fig 13 on page 26) Page 12 of 30 • Lateral route (through the thoracoepigastric vein) may be also involved. These connections in the periumbilical area are termed "caput medusae" (fig 14 on page 27) Therefore, paraumbilical vein may be involved as collateral pathway in superior and inferior vena cava stenosis and in portal hypertension, but blood flow direction is the opposite. Page 13 of 30 Page 14 of 30 Images for this section: Fig. 1: 73-year-old man with chronic occlusion of the infrarenal aorta. A: Coronal MIP shows complete occlusion of infrarenal aorta (black arrows), and repermeabilzation of external iliac arteries (white arrows). B: Sagital MIP shows collateral pathways on the left abdominal wall through superior epigastric (red arrow) and intercostal arteries (orange arrows), which anastomose with inferior epigastric artery (white arrow). Inferior intercostal Page 15 of 30 arteries (green arrows) are also seen, which connect with the external iliac artery through the deep circumflex artery (yellow arrow). Fig. 2: Volume rendering in the same patient (A) shows retrograde flow into inferior epigastric (white arrows) and deep circumflex arteries (yellow arrows). Left inferior gluteal artery (blue arrow) is also seen, which communicates with the homolateral lumbar arteries (green arrows), as shown in axial MIP (B). Page 16 of 30 Fig. 3: 75-year-old man with right common iliac and left external iliac occlusion. A: Frontal volume rendered image shows communication between lumbar arteries (green arrows) and deep circumflex arteries (yellow arrows). B: Lateral MIP reconstruction shows anastomoses between inferior (white arrow) and superior (red arrow) epigastric arteries in the same patient. Page 17 of 30 Fig. 4: 47-years old woman with right lung cancer. A: Coronal MPR shows a tumoral mass in the right upper lobe with superior vena cava and azygos (black arrow) obstruction. B: Coronal MIP depicts retrograde flow through the tributaries of internal mammary veins (blue arrows), musculophrenic veins (red arrows), superior epigastric veins (red arrows) and a periumbilical branches (purple). Page 18 of 30 Fig. 5: A: Lateral MIP partially shows two different collateral circulation systems: superficial thoracic veins (white arrows) connect with periumbilical branches (purple arrows) and superficial epigastric veins (orange arrows), which are tributaries of the internal saphena veins; internal mammary veins (blue arrows) communicate with superior epigastric veins (red arrow) which supply the external iliac veins through the inferior epigastric veins (green arrows). B: Axial MIP shows the relationship between superficial and inferior epigastric veins. Superficial circumflex veins are also seen (yellow arrows). Page 19 of 30 Fig. 6: Volume rendering shows extensive collateral circulation on the surface of the thoracic wall and its communication with the superficial collateral pathways on the anterior abdominal wall. Two main routes are depicted: lateral thoracic veins connect with the thoracoepigastric veins and these supply the internal saphena veins through the superficial circumflex veins; superficial epigastric veins result from a complex net of superficial veins on the anterior thoracoabdominal wall and flow into the femoral veins. Page 20 of 30 Fig. 7: 58-year-old woman in chemotherapic treatment for colon cancer with liver metastases. A: Coronal MIP shows a superior vena cava occlusion induced by the central venous catheter (white arrow). B: Lateral MIP shows collateral venous circulation around the superior vena cava and retrograde flow through the internal mammary vein (blue arrows), which connect with a superficial vein on the epigastric region (black arrows). Page 21 of 30 Fig. 8: Evolution of the abdominal wall superficial collateral circulation in the same patient. Thrombosis of the superior vena cava is detected in January, and the central venous catheter is removed. Nevertheless, thrombosis remains and collateral circulation on the anterior abdominal wall progressively develops. Page 22 of 30 Fig. 9: A: 86-year-old man with neoplastic mass in the right upper lobe, who presented with left brachiocephalic vein obstruction. B: Collateral pathway communicates left subclavian vein with the opposite superficial epigastric veins through a superficial thoraco-abdominal anastomosing vein. Page 23 of 30 Fig. 10: 74-year-old man with hypernephroma and tumoral thrombus in the left renal vein and inferior vena cava (large arrows). Although intraabdominal collateral pathways are seen (red arrows), abdominal wall collateral circulation could not be detected. Page 24 of 30 Fig. 11: A: 79-year-old man with cirrhosis and possible malignant degeneration (white arrows). Thrombosis of the left portal branch (black arrow) is seen. B: Coronal MIP shows anastomoses between paraumbilical vein (purple arrow) and internal mammary veins (blue arrows). Page 25 of 30 Fig. 12: 78-year-old woman with alcohol-induced cirrhosis. Coronal MIP (A, B) show collateral pathways through tortuous gastrorenal (small arrows) and spleno-renal shunts, seen around the left kidney ( large arrows). Page 26 of 30 Fig. 13: Abdominal wall collateral pathways in the same patient. A: Volume rendering shows superficial epigastric veins (orange arrows), circumflex iliac veins (yellow arrows) and thoracoepigastric veins (white arrows). B: Lateral MIP shows superficial and deep abdominal wall collateral pathways arising from the periumbilical zone: superficial epigastric vein (orange arrows) and thoracoabdominal superficial veins (purple arrows); inferior epigastric (green arrows) and superior epigastric veins (red arrow). Page 27 of 30 Fig. 14: 61-year-old woman with cirrhosis. Volume rendered image shows the communication between paraumbilical vein and the superficial veins of the abdominal wall, also called "caput medusae". Page 28 of 30 Conclusion 64-slice multidetector CT angiography: • • Allows superb depiction of arterial and venous collateral pathways of the abdominal wall Provides useful information about its etiology and significance. Personal Information References 1. 2. 3. 4. 5. Sebastià C, Quiroga S, Boyé R, Perez-Lafuente M, Castellà E, AlvarezCastells A. Aortic stenosis: spectrum of diseases depicted at multisection CT. Radiographics. 2003 Oct;23 Spec No:S79-91. Bashist B, Parisi A, Frager DH, Suster B. Abdominal CT findings when the superior vena cava, brachiocephalic vein, or subclavian vein is obstructed. AJR Am J Roentgenol. 1996 Dec;167(6):1457-63. Sonin AH, Mazer MJ, Powers TA. Obstruction of the inferior vena cava: a multiple-modality demonstration of causes, manifestations, and collateral pathways. Radiographics. 1992 Mar;12(2):309-22. Dahan H, Arrivé L, Monnier-Cholley L, Le Hir P, Zins M, Tubiana JM. Cavoportal collateral pathways in vena cava obstruction: imaging features. AJR Am J Roentgenol. 1998 Nov;171(5):1405-11. Cho KC, Patel YD, Wachsberg RH, Seeff J. Varices in portal hypertension: evaluation with CT. Radiographics. 1995 May;15(3):609-22. Page 29 of 30 6. Kang HK, Jeong YY, Choi JH, Choi S, Chung TW, Seo JJ, Kim JK, Yoon W, Park JG. Three-dimensional multi-detector row CT portal venography in the evaluation of portosystemic collateral vessels in liver cirrhosis. Radiographics. 2002 Sep-Oct;22(5):1053-61. Page 30 of 30