Abdominal Vascular System (1) PDF

Chapter 8 Page 141 1  Abdominal Vasculature Used as landmarks for locating organs/structures Will be interrogated for clot (thrombus), tumor, transplant rejection, etc… 2  Arteries Transport blood away from t...

Chapter 8 Page 141 1  Abdominal Vasculature Used as landmarks for locating organs/structures Will be interrogated for clot (thrombus), tumor, transplant rejection, etc… 2  Arteries Transport blood away from the heart. Branch into smaller and smaller arteries The smallest branches are called arterioles. Arterioles lead into the capillaries, where the exchange of nutrients and waste products between the blood and tissue fluid occurs. 3 Abdominal Arterial System Pg.145 Fig. 8-5 4  Veins Carry blood toward the heart After passing through the capillaries, the blood is collected into venuoles. Venuoles are the smallest veins. The venuoles join to form larger veins which join to form still larger veins The veins continue to get progressively larger until the blood gets returned to the heart for recirculation. 5 Arterial Wall Structure (3 Layers) 1.Tunica Intima 2. Tunica Media 3. Tunica Adventitia 6  Arterial Wall Structure 1.Tunica Intima- inner layer consisting of: A layer of endothelial cells—lines arterial lumen A layer of connective tissue An elastic layer made up of elastic fibers 7 2. Tunica Media- middle layer consisting of: Smooth muscle fibers with elastic and collagenous tissue 3.Tunica Adventitia- consisting of: loose connective tissue with bundles of smooth muscle and elastic tissue 8  Venous Wall Structure *same three layers, but with the following differences: Tunica Media= much thinner, hardly any elastic or smooth muscle tissue in the wall. The diameter of the veins is much larger, and blood moves slowly. Veins are collapsible. Veins contain special valves to prevent backflow. Venous flow is aided by contractions of skeletal muscles, overflow from capillary beds, gravity, and negative thoracic pressure. 9 Pg. 142 Fig. 8-1 10 Artery v/s Vein Cross Section Pg. 142 Fig. 8-1 11  Capillaries Tiny hair-size vessels which connect the arteries to the veins. The walls have only one layer. Nutrients pass out of the blood through the capillary walls Waste products pass from the interstitial fluid into the blood at the same time. 12  Anastomosis Arteries don’t always end in capillary beds. Sometimes they make an anastomosis directly with another vessel A communication between two blood vessels without any intervening capillary network 13 Anastomosis 14 Aorta 15  Aorta *The largest artery of the body. 5 sections: 1. The Aortic Root 2. Ascending Aorta (arch) 3. Descending Aorta (thoracic) 4. Abdominal Aorta 5. Bifurcation (Rt. and Lt. Common Iliac Arteries) 16  /Innominate See Pgs.145, 143, 152 Fig. 8-5, 8-2, 8-15 17  Aorta 1.Aortic Root: Arises from left ventricular outflow tract of the heart. 2.Ascending Aorta: Forms the aortic arch 18  Aortic Arch Three arterial branches arise from the superior aortic arch to supply the head, neck and arms: 1. Right innominate/Brachiocephalic-right neck and arm 2. Left Common Carotid- left neck 3. Left Subclavian—left arm 19  * * * 20  Descending/Thoracic Aorta Descends posteriorly along back wall of heart through thoracic cavity where it crosses the diaphragm. 21  /Innominate See Pgs. 145, 143,152 Fig. 8-5, 8- 2, 8-15 22  Abdominal Aorta Runs anterior to vertebral column (retroperitoneal) to the level of the umbilicus (4th lumbar vertebra) where it bifurcates into the right and left Common Iliac Arteries (which then divide into External and Internal) 23  Abdominal Aorta The abdominal aorta has 4 branches that supply visceral organs and the mesentery: 1.The Celiac Axis 2.The Superior Mesenteric Artery (SMA) 3.The Renal Arteries 4.The Inferior Mesenteric Artery (IMA) 24 Superior Celiac Trunk Mesenteric Artery Lt Renal Artery Rt Renal Inferior Mesenteric Artery Artery Lt. External Iliac Artery Common Iliac Artery Lt. Internal 25 Iliac Artery  The Celiac Axis/Trunk 3 Branches: 1.Hepatic Artery 2.Splenic Artery 3.Left Gastric Artery The celiac vessels feed the liver, spleen, stomach, pancreas, and duodenum. 26  The Celiac Axis/Trunk 1. Common Hepatic Artery—Right branch of Celiac Trunk. Branches into the Gastroduodenal Artery and the Hepatic Artery Proper. Common Hepatic Artery passes anterior to the portal vein to enter the liver at the porta hepatis (enters liver with Portal Vein and CBD in Portal Triad.) Then branches (along with portal vein)into the Rt & Lt Hepatic Arteries. Left Hepatic Artery-supplies caudate and left lobes of liver Right Hepatic Artery-supplies the gallbladder and the liver. 27  The Celiac Axis/Trunk 2. Splenic Artery-largest branch of celiac trunk, runs left and forms the superior border of pancreas. It Branches into left gastroepiploic artery, short gastric artery, and branches that feed the spleen. The vessels that feed the pancreas come off the splenic artery. 3. Lt. Gastric Artery-Rarely seen during aorta ultrasound 28 Pg. 154 Fig. 8-18 29 Celiac Trunk Pg. 153 Fig. 8-17 30 Celiac Trunk/Axis :Transverse Pg. 154 Fig 8-19 “Seagull” sign 31 Celiac Trunk/Axis :Sagittal Pg. 146 Fig. 8-6 32  Superior Mesenteric Artery (SMA) The second anterior aortic branch. Runs posterior to neck of pancreas and anterior to the uncinate process of the pancreas, then branches to feed the mesentery and the colon. Sometimes, the Hepatic Artery will arise from the SMA instead of the Celiac Axis. 33 Pg. 154 Fig. 8-18 34  Superior Mesenteric Artery (SMA) 5 Major Branches: Inferior pancreatic artery, duodenal artery, colic artery, ileocolic artery, and intestinal artery These vessels supply the small bowel, extend into the mesentery, and unite with other arteries to form loops (arcades). *They then go on to feed the proximal half of the colon (cecum, ascending, & transverse) and the small intestine. 35 SMA Branches Pg. 157 Fig. 8-23 36  Superior Mesenteric Artery (SMA) Takes a parallel course anterior to the aorta. Easily seen in longitudinal plane. Looks like circle in echogenic sheath on transverse images. This echogenic “sheath” is the retroperitoneal fascia. 37 SMA Pg. 157 Fig. 8-24 38  Superior Mesenteric Artery (SMA) The angle of SMA origin, in relation to the Aorta should be 15 degrees or less. If the angle is greater lymphadenopathy may be indicated. 39 Pg. 157 Fig. 8-25 Lymphadenopathy 40  Renal Arteries Lateral branches of the aorta Inferior to the SMA ,at about the level of the 1st lumbar vertebra. Both right and left renal arteries branch to form the Anterior and Inferior Suprarenal Arteries. Right Renal Artery- longer than the left renal artery. Runs posterior to the IVC and anterior to the vertebral column into the hilum of the right kidney. Left Renal Artery- runs from aorta directly into hilum of left kidney. 41 Renal Arteries Pg. 159 Fig. 8-28 42 Renal Arteries -Transverse Pg. 159 Fig. 8-29 Posterior to IVC 43 Renal Arteries -Sagittal Pg. 159 Fig. 8-29 44  Right Renal Artery Variants Can be seen anterior vs. posterior to the IVC Duplication is common 45 Fig. 8-31 Pg.160 Right Renal Artery Anterior to the IVC 46  Pg. 159 Fig. 8-30 Duplicated Right Renal Artery 47  Inferior Mesenteric Artery (IMA) Arises anteriorly from aorta at about level of 3- 4th lumbar vertebra. Has 3 main branches: left colic, sigmoid, and superior rectal arteries Supplies the left transverse colon, descending colon, sigmoid, and rectum. Very difficult to image sonographically. When seen, is usually in longitudinal plane. 48 Inferior Mesenteric Artery Pg. 157 Fig. 8-26 49  Bifurcation of Aorta into Common Iliac Arteries Aorta bifurcates (splits) into the Right and Left Common Iliac Arteries at about the level of the umbilicus. Each Common Iliac divides into the Internal and External Iliac Arteries. 50 Iliac Arteries Pg. 153 Fig. 8-16 A. 51  Internal Iliac Arteries Internal Iliac Artery (Rt and Lt)- crosses into pelvis anterior to sacroiliac joint. Branches into anterior and posterior branches to feed the Pelvic Viscera, Peritoneum, Buttocks, and Sacral Canal. 52  External Iliac Arteries External Iliac Artery (Rt and Lt)- runs along psoas muscle then crosses inguinal ligament to become the Common Femoral Artery. (supplies legs) 53 Abdominal Arterial System Pg. 152 Fig. 8-15 54  Ultrasound Imaging of The Aorta An ultrasound exam of the aorta may be ordered for the following reasons: To Assess its diameter (stenosis,aneurysm) Visualize any possible thrombus, calcification, or dissection of the aortic wall. Commonly used to assess for aortic aneurysm. 55  Aorta Sonogram-Patient Preperation Patient should be NPO Patient should be in a supine position 56  Aorta Ultrasound Imaging Images should document the entire aorta from just below the diaphragm to the bifurcation. Sagittial and Transverse images must be obtained. The aorta lumen should be anechoic (may need to turn down gain) Normally, the diameter of the aorta tapers distally. Absence of this tapering = aortic ectasia. Try to keep the transducer perpendicular to the aorta at all times to ensure accurate measurements. 57 Inferior Vena Cava (IVC) 58  Inferior Vena Cava (IVC) Formed by confluence of the Right and Left Common Iliac Veins at about the level of the umbilicus. Runs anterior to spine to the right of the aorta through the abdomen. Crosses diaphragm and enters the right atrium of the heart. Is separated from the portal vein by entering the 59 lesser sac.  Inferior Vena Cava (IVC) The IVC is a landmark for many abdominal structures. It should always be evaluated for thrombus or other abnormality. May do specific exam of IVC, generally to evaluate for thrombus, tumor invasion, or extrinsic compression. 60 Pg. 171 Fig. 8-49 IVC Posterior to Portal vein and Hepatic Artery 61  Inferior Vena Cava (IVC) Dilatation of the IVC can be indication of Rt Ventricular Heart Failure, Congestive Heart Disease, Constrictive Pericarditis, Tricuspid Disease, Rt Heart Obstructive Tumors *Heart Problems: Right side in particular 62 Dilated IVC in a pt. with Rt. Heart failure Pg. 174 Fig. 8-57 63  Inferior Vena Cava (IVC) Patient should be NPO and placed in supine position. May image IVC with patient on left side to avoid bowel gas Instructing patient to hold his/her breath will cause the IVC to dilate (increase in diameter) 64  IVC Tributaries 1. Hepatic Veins 2. Rt Adrenal Vein *All the organs and structures 3. Rt and Lt Renal Veins in the abdomen 4. Rt Testicular or Ovarian Vein drain via these main 5. Inferior Phrenic Vein tributaries 6. 4 Lumbar Veins 7. Rt and Lt Common Iliac Veins 8. Median Sacral Vein 65 The abdominal venous system Pg. 169 Fig. 8-46 66  Hepatic Veins Largest visceral tributaries of the IVC. Originate in liver and drain into IVC at the diaphragm. Three branches: 1.Right Hepatic Vein-drains Right Lobe 2.Middle Hepatic Vein-drains Caudate Lobe 3.Left Hepatic Vein-drains Left Lobe 67 Hepatic Veins Pg. 178 Fig. 8-67 68 Hepatic Veins Pg. 174 Fig. 8-57 69  Hepatic Veins Vs. Portal Veins The hepatic veins run more in the longitudinal plane than the portal veins ,toward the diaphragm and then to the right toward the IVC. The hepatic veins have thinner walls compared to the echogenic edge of the portal vein. 70 Hepatic Veins Vs. Portal Veins See Also Pg. 195 Fig. 9-6 71 Portal Veins vs Hepatic Veins Pg. 171 Fig. 8-49 D. 72  Hepatic Veins Transversely, the hepatic veins can be seen draining into the IVC if the transducer is angled in a cephalad direction from the area of the xyphoid process. This image is known as the “Playboy Bunny” or “Reindeer” sign. 73 Transverse-Hepatic Veins Pg. 212 Fig. 10-13 74  Renal Veins 5-6 branches join to form main renal vein on each side. Right Renal Vein- flows directly from rt kidney to posterolateral IVC. Usually there are no tributaries into it outside the kidney. The right adrenal and gonadal veins drain directly into the IVC. 75  Renal Veins Left Renal Vein- Exits hilum of kidney on medial side. Flows from lt kidney to IVC. Is larger than rt renal vein Accepts tributaries from the left adrenal, left gonadal, and lumbar veins. Courses between the aorta and SMA 76 Right Renal Vein Pg. 177 Fig. 8-63 77 Left Renal Vein Pg. 191 Fig. 9-38 (7th Ed.) 78  Lt. Renal Vein Pg. 177 Fig. 8-62 Lt. Renal Vein Crossing Anterior to Aorta 79  The Portal Vein Formed posterior to the pancreas by the confluence of the Superior Mesenteric Vein (SMV) and Splenic Vein near the pancreas. The portal vein trunk is 5-7cm long. It runs posterior to the proximal duodenum, through the layers of the lesser omentum to the porta hepatis, where it branches into the Right and Left Portal Veins. 80  The Portal Vein The portal vein carries blood from the GI tract to the liver for detoxification. It drains blood from the GI tract starting at the lower esophagus all the way to the upper end of the anal canal, from the pancreas, gallbladder, bile ducts, and spleen. 81 SMV + Splenic Vein = Portal Vein Pg.180 Fig. 8-70 82  The Portal Vein The portal vein communicates with the esophageal veins, rectal venous plexus, and superficial abdominal veins—these are sites that will become dilated and form varices in patients with portal hypertension. Blood from the portal vein goes through the liver and drains into the IVC via the hepatic veins. 83  The Portal Vein The portal veins run in a generally transverse plane and are easily recognized by the echogenic echoes that surround the portal triad. 84 Transverse- Portal Vein Pg. 181 Fig. 8-71 Left Portal Vein branching Into Medial And Lateral segments 85 Transverse- Portal Vein Pg. 181 Fig. 8-71 Main Portal Vein branching into Rt. Anterior And Posterior 86 Main Portal Vein -Anterior to IVC Pg. 172 Fig. 8-52 87  Splenic Vein Begins at hilum of spleen and receives drainage from the short gastric vein and the left gastroepiploic vein. It runs along the posterior/medial border of the pancreas and receives drainage from the pancreatic veins and the inferior mesenteric vein. At the neck of the pancreas, it joins the SMV to form the Portal Vein at the Portal Confluence. 88 Splenic Vein Pg. 180 Fig. 8-70 89  Splenic Vein Pg. 180 Fig. 8-70 90 Splenic Vein Pg. 318 Fig. 2-14 91 Splenic Vein + SMV = Portal Vein Pg.180 Fig.8-70 92 Superior Mesenteric Vein (SMV) Begins at junction of ileum and colon. Runs through abdominal mesentery, passes anterior to distal duodenum and posterior to pancreatic neck to join the Splenic Vein to make the Portal Confluence. 93 Superior Mesenteric Vein (SMV) Drains blood from the following: Middle Colic Vein- transverse colon Rt Colic Vein – ascending colon Pancreatic Duodenal Vein-pancreas & duodenum 94 Superior Mesenteric Vein (SMV) Generally found anterior to the IVC and to the right of the SMA. Seen just inferior to the classic pancreas /Splenic Vein image. *You should not be able to see the SMV, Splenic Vein, and Portal Vein all in the same transverse plane. 95 SMV-Transverse 96  Superior Mesenteric Vein Sag. Posterior to the head In a slightly oblique/sagittal of the pancreas and the plane, the splenic vein can be anterior border of the seen emptying into the Portal uncinate process of the Vein. Pg. 182 Fig. 8-73 pancreas. 97  Inferior Mesenteric Vein Arises from the left 1/3 of the colon and upper colon. Runs along the left psoas muscle. Starts out as the superior rectal vein. Joins the splenic vein posterior to the pancreas. *Virtually impossible to identify on ultrasound due to overlying bowel and the lack of adjacent landmarks. 98 Inferior Mesenteric Vein 99  Inferior Mesenteric Vein Pg. 180 Fig. 8-70 100  Inferior Mesenteric Vein Drains: Descending colon Sigmoid colon Upper rectum 101  Reference Hagen-Ansert, Sandra. (2012). Textbook of diagnostic ultrasonography, vol. 1 & 2, 7th and 8th edition. Mosby Publishers. 978-0-323-07301-1,978-0-323-35375-5 102