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Abdominal Sonography 2 Lecture 14 Abdominal Vascular Parts A and B Holdorf Contents Part A Abdominal Vasculature physiology Layers of the arterial wall Arterial Anatomy The aorta Aortic aneurysms Main visceral branches of the abdominal aorta CONTENTS PART B Venous anatomy Inferior Vena Cava Main Venous Tributaries Aorta and IVC Locations Aorta and IVC size IVC sonographic appearance Abdominal Vasculature Examination Technique Abdominal Arterial Pathology Abdominal Venous Pathology Abdominal Vasculature Physiology Functions of the Vascular System: Arteries and arterioles carry oxygenated blood away from the heart Veins and venules carry blood toward the heart Capillaries connect the arterial and venous systems Extremity veins contain valves Valves extend inward toward the intima VESSEL WALL LAYERS Venous walls are thinner and less elastic when compared with arterial walls Tunica adventitia Outer layer Lends greater elasticity to the arteries Tunica media Middle muscle layer Helps to regulate blood flow by controlling the vessel wall diameter Tunica intima Inner layer Comprised of a single layer of cells giving it a smooth surface Arterial Anatomy ABDOMINAL AORTA Originates at the diaphragm and courses inferiorly until it bifurcates into the right and left common iliac arteries Tapers in size as it courses anterior and inferior in the abdomen Common iliac arteries are the terminal branches of the abdominal aorta. Common iliac artery bifurcates into the external and internal (hypogastric) iliac arteries. External iliac artery becomes the common femoral artery after passing beneath the inguinal ligament Internal iliac artery bifurcates into anterior and posterior divisions Aorta cont. Diameter: Proximally 2-2.5 cm At bifurcation 1.5 cm Ectatic tortuous. (3cm) abdominal aorta is seen with age and is usually Aneurysm > 3cm US Appearance: Anechoic Tubular structure Pulsatile High resistance flow. Ventral branches of AA: Celiac Axis( Trunk): 1-3 cm in length. Splenic A; SA- is on its way to the spleen, tortuous and difficult to visualize, courses superior to Panc. Supplies spleen , panc, lt side of greater curvature. LGA (Lt. Gastric A.) - Usually not seen on US. Courses superior and to the left. Supplies left side of the lesser curvature and eventually anastomosis with RGA. Common Hepatic A. ( CHA); enters porta hepatis with PV. GDA (Gastroduodenal A.) – is the first branch of CHA, has a caudal course. delineates the Anterolateral aspect of the HOP: supplies the duodenum, parts of stomach and HOP. Ventral branches of AA Cont. Superior Mesenteric Artery(SMA)- Post to body of Panc. On trv. View. In sag. runs parallel and ant. to the aorta. Supplies small intes. (jejunum, ileum), HOP,cecum ascending colon & part of transv. Colon. Doppler signature ( fasting /post prandial) Inferior Mesenteric Artery (IMA)- Originates from Ao. close to the umbilicus. Rarely seen on US. Supplies blood to the left transverse colon, the descending and sigmoid colon, and upper rectum. Doppler signature; very high resistant Lateral Branches Of Aorta 1. Right Renal Artery- Is the Only vessel that courses 2. Left Renal Artery- LRA < RRA posterior to IVC. Notes: 33%population have accessory RAs. Normal Doppler signature – High diastolic They branch from Aorta 1-1.5 cm distal to the SMA Gonadal Arteries- They arise off the anterolateral aspect of the aorta, inferior to the renal arteries and are difficult to visualize on US. Scanning techniques for evaluation of Aorta Long and Transverse views Begin at the level of diaphragm and follow to Aortic bifurcation. Because a significant # of AAAs involve Iliac arteries, they should be also evaluated as part of Aortic exam. Look for thrombus, intimal flaps and any paraortic masses. Measurement are done in; TRV, AP Outside to outside wall. Scanning techniques for evaluation of Aorta cont. Although 95% of AAA are below the level of renal arteries > try to identify the level of RAs. Note- Prox. Ao. Is seen posterior to IVC Be aware of Anatomical varieties/abnormalities; Interruptiontransposition. Aorta has a high resistant Doppler signature. Keywords Abdominal aortic aneurysm – dilatation of the aorta equal to or exceeding 3 cm in diameter; Aka: AAA Aneurysm – a localized widening or dilatation of a blood vessel. Arteriovenous fistula – an abnormal connection between an artery and vein; Aka: arteriovenous shunting Berry aneurysm – small saccular aneurysms primarily affecting the cerebral arteries Dissecting aneurysm – a result of a tear in the intimal lining of the artery creating a false lumen within the media. This false lumen allows blood to dissect the media and adventitia layers. Ectatic aneurysm – dilatation of an artery when compared with a more proximal segment. In cases of abdominal aorta the ectatic dilatation does not exceed 3.0 cm. Fusiform aneurysm – characterized by a uniform dilatation of the arterial walls; most common type of abdominal aortic aneurysm Mycotic aneurysm – a saccular dilatation of a blood vessel caused by a bacterial infection. Pseudoaneurysm – dilatation of an artery due to damage to one or more layers of the arterial wall caused by trauma or aneurysm rupture; Aka: pulsatile hematoma Saccular aneurysm – dilatation of an artery characterized by a focal out-pouching of one arterial wall; most often due to trauma or infection. Dissecting (Pseudo) Aneurysm Ectatic Aneurysm Fusiform aneurysm Mycotic aneurysm Saccular aneurysm Aortic Aneurysm Aneurysm= localized dilatation of a weakened part of an arterial wall. NL Aortic diameter < 3cm NL Iliac a. =1.5 cm (1.3 cm in female) Renal arteries: located 1.5 cm dist. to SMA AAA= focal enlargement > 3cm AP diameter Rare< 50 Y 70-90% AAAs occur in men> 65 Y Major causes: 1. 2. 3. 4. Idiopathic : The most common, usu. Infrarenal and associated with atherosclerosis Congenital defects Infection: Syphilis Trauma Histological AAA Classification True Aneurysm: All 3 layers of arterial wall are stretched. A minority of them are due to rare identified underlying diseases such as Marfan’s Syndrome, however the majority of true aneurysms are idiopathic with a multifactorial origin. (atherosclerosis, smoking, hyperlipidemia) False Aneurysm: A hole in the wall allows leakage of blood, ex. Trauma, Infection (Mycotic Aneurysm), graft anastomoses. Dissecting aneurysm: A special type of pseudoaneurysm, separation of the intima and media; creating a false lumen. AAA Types Fusiform; diffuse (gradual)- most common Bulbous; focal (sharp) Eccentric, Saccular- usually due to trauma SAG AAA AAA Symptoms Pulsatile abdominal mass, abdominal bruit Abdominal pain, may radiate to back If ruptures; hypotensive shock (50% mortality rate) Growth rate: 0.2-0.5 cm/year AAAs usually are silent and can be lethal. US Role in AAA Identify unknown aneurysm Surveillance of the known AAAs Surgical follow up Technique: Prox., mid., dist.- outer wall to outer wall Trans. And long. 2 cm rule: Are the renal arteries involved? You can measure the residual lumen and show how much flow pass through Note: Aortic tortuosity due to aneurysm AAA Treatment Note; if > 6cm candidate for surgery, and if > 7cm- 75% risk of fatal rupture. Treatment of AAA: Open repair; not common any more Endovascular Aortic graft ( p. 474 Rumack): An endovascular stent is placed transluminal. Mesenteric arteries SMA and IMA- High resistance SMA fasting < or = 156 cm/s ED=11-16 cm/s postprandial EDV rises Celiac- Low resistance Celiac fasting < or = 122 cm/s ED=32-35 cm/s postprandial No change Main Visceral Branches of the Abdominal Aorta Celiac Axis (CA) First major branch of the abdominal aorta Arises from the anterior aspect of the aorta Branches into the splenic, left gastric and common hepatic arteries 1-3 cm in length Low resistance blood flow with continuous forward flow in diastole Peak systolic velocity remains unchanged after a meal Celiac Axis Superior Mesenteric Artery (SMA) Second major branch of the abdominal aorta Arises from the anterior surface of the aorta, inferior to the celiac axis Courses inferiorly and parallel to the aorta Branches supply: jejunum, ileum, cecum, ascending colon, portions of the transverse colon and the head of the pancreas High resistance multiphasic blood flow when fasting Low resistance elevated systolic and diastolic velocities with continuous forward flow in diastole following a meal Distance from the anterior wall of the aorta to the posterior wall of the SMA should not exceed 11 mm. SMA Mesenteric Ischemia Rare due to vast collateral system It is caused by the low blood supply to the intestine. Requires significant stenosis of both Celiac and SMA Can be: Acute( Life threatening) Chronic ( Fear of food) US Criteria for DX: “ 2 artery rule” SMA > 275 cm/s Celiac > 200 cm/s Hint: Low R signal in SMA during fasting. Middle Supra-renal Arteries Arise from the lateral aspect of the abdominal aorta Courses laterally and slightly superior over the crura of the diaphragm to the adrenal glands Supra-renal arteries Main Renal Arteries Arise from the posterior lateral aspects of the abdominal aorta Located 1.0 – 1.5 cm inferior to the superior mesenteric artery Course posterior to the renal veins Right side arises superior to the left and courses posterior to the inferior vena cava Renal artery bifurcate into segmental arteries at the renal hilum Renal artery gives rise to the inferior suprarenal artery Low resistance blood flow with continuous forward flow in diastole Duplicated arteries are found in 10- 20 percent of the population Main Renal Arteries Renal Artery Aneurysm Uncommon Usually Pseudoaneurysm Etiology: Congenital Post-traumatic: more common, ex. Post BX Renal artery stenosis Causes are rare (2%), but treatable form of hypertension. Ethology: Atherosclerosis ( usu. Affects prox. RA) Fibromuscular hyperplasia (usu. Affects mid to distal RA): Rare Affecting young women Patient population: Young people with acute onset of difficult to control HT, sever HT with diastolic > 115 mmHg Renal artery stenosis cont. Treatment: Angioplasty/ stent US Diagnostic Criteria: RAR or RENAL AORTIC RATIO > 3.5 PSV> 180 cm/s Acceleration time (AT) > 0.07(0.1) second Loss of early systolic peak (ESP) NL Renal Artery Spectral Doppler Renal Vein Thrombosis Causes: Renal disease; Acute glomerulonephritis Renal tumors: Renal cell CA, Wilm’s tumor, Lymphoma Lupus Amyloidosis Hypercoagulable states Sepsis Trauma Kidney transplant (1% of pts with renal transplant) Renal Vein Thrombosis cont. Clinical signs/symptoms: Acute; Large kidneys, flank pain, hematuria Chronic; atrophic kidneys, hematuria, proteinuria US findings: Acute; enlarged hypoechoic kidneys Chronic: small echogenic kidneys Doppler study shows no renal vein flow/thrombus, and high R. arterial pattern Gonadal Arteries Arise from the anterior aspect of the abdominal aorta inferior to the renal arteries Course parallel to the psoas muscle into the pelvis Low resistance blood flow with continuous flow through diastole Not visualized with ultrasound Gonadal Arteries Inferior Mesenteric Artery Last major branch of the abdominal aorta prior to the aortic bifurcation Arises from the anterior aorta Courses inferior and to the left of midline Supplies the left transverse colon, descending colon, upper rectum and sigmoid Visualized on ultrasound in an oblique plane, slightly to the left of midline and approximately 1 cm superior to the aortic bifurcation Low resistance blood flow with continuous flow through diastole IMA MAIN PARIETAL BRANCHES of the ABDOMINAL AORTA Inferior Phrenic Artery Arise from the anterior aspect of the abdominal aorta branching into the right and left inferior phrenic arteries artery just below the diaphragm near the level of the 12th thoracic vertebrae. Supplies the inferior portion of the diaphragm Gives rise to the superior suprarenal artery Inferior Phrenic Artery Lumbar Arteries Four arteries arise on each side of the abdominal aorta Supplies the abdominal wall and spinal cord Located inferior to the gonadal arteries and superior to the inferior mesenteric artery Median sacral artery Located inferior to the inferior mesenteric artery and superior to the aortic bifurcation. Lumbar Arteries Median/middle sacral artery ADDITIONAL ABDOMINAL ARTERIES Gastroduodenal artery (GDA) Branch of the common hepatic artery Lies between the superior portion of the duodenum and the anterior surface of the pancreatic head GDA Hepatic Artery Common hepatic artery is a branch of the celiac axis Gives rise to the gastroduodenal artery and is now termed the proper hepatic artery Courses adjacent to the portal vein The proper hepatic artery bifurcates into the right, middle and left hepatic arteries at the hepatic hilum Low resistance blood flow with continuous flow through diastole Increased flow velocity is associated with jaundice, cirrhosis, lymphoma and metastases Hepatic Artery Splenic Artery Tortuous branch of the celiac axis Gives rise to the left gastroepiploic artery and additional branches to the pancreas and stomach Courses along the superior margin of the pancreatic body and tail Low resistance blood flow with continuous flow through diastole May be mistaken for a dilated pancreatic duct Splenic Artery End Part A Abdominal Vasculature Begin Part B Abdominal Vasculature VENOUS ANATOMY Inferior Vena Cava (IVC) Formed at the junction of the right and left common iliac veins Carries oxygen depleted blood from the body superiorly to the right atrium of the heart Major abdominal branches include: lumbar veins, right gonadal vein, renal veins, right suprarenal vein, inferior phrenic vein and hepatic veins. IVC IVC IVC pathologies Congenital Anomalies Duplication Transposition Interruption Obstruction Extrinsic: Tumors, Hematoma Intrinsic Thrombosis The most common intraluminal IVC anomaly IVC tumor invasion origin; 1. 2. 3. 4. 5. 6. Renal cell CA; most common Wilm’s tumor Adrenal CA Hepatoma Lymphoma Renal angiomyolipoma Budd-Chiari Syndrome Thrombosis of IVC, hepatic veins, and their tributaries. Symptoms: Hepatomegaly, Abd. pain, ascites, abnormal liver lab. results. US Protocol for the Budd-Chiari syndrome Document the patency and flow direction within the HVs, IVC, as well as Portal and splenic veins. B-mode; shows the intraluminal thrombus Doppler; shows no flow within the IVC If it is a tumor the arterial flow may be seen within the thrombus. Note-As part of the treatment, IVC filters are being inserted within IVC to prevent PE. MAIN VENOUS TRIBUTARIES Common Iliac Veins Drain blood from the lower extremities and pelvis Formed by the junction of the external and internal iliac veins Common Iliac Veins Renal Veins Course anterior to the renal arteries Left renal vein courses posterior to the superior mesenteric artery and anterior to the abdominal aorta Left renal vein receives the left suprarenal and gonadal veins Left renal vein may appear dilated due to compression from the mesentery Right renal vein has a short course to the IVC Demonstrates spontaneous phasic blood flow Renal Veins Hepatic Veins Lie at the boundaries of the hepatic segments and course toward the IVC Three major branches: left, middle and right hepatic veins Right hepatic vein courses coronally between the anterior and posterior segments of the right hepatic lobe Middle hepatic vein follows an oblique course between the left and right hepatic lobes Left hepatic vein courses posterior between the medial and lateral segments of the left hepatic lobe Doppler demonstrates spontaneous, multiphasic and pulsatile blood flow toward the IVC (hepatofugal) Increase in blood flow with inspiration and diminished flow with Valsalva maneuver NL and AbNL Hepatic veins Doppler signals Hepatic Veins ADDITIONAL ABDOMINAL VEINS Main Portal Vein Drains the gastrointestinal tract, pancreas, spleen and gallbladder Provides approximately 70 % of the liver’s blood supply Formed by the junction of the splenic and superior mesenteric veins Bifurcates into the right and left portal veins Should not exceed 1.3 cm in diameter Demonstrates phasic low flow velocities towards the liver (hepatopetal) Blood flow will decrease with inspiration Diameter will increase after a meal Additional tributaries include coronary vein – enters at the superior border of the porto-splenic confluence inferior mesenteric vein – enters at the inferior border of the porto-splenic confluence Portal Vein Portal v. bring blood from Spleen, pancreas, stomach, and intestine to the liver. Is formed at portal-splenic confluence from the junction of SMV and SV posterior to the neck of Pancreas (at level of L2) and then courses cephalad , ant. to the IVC and enters the liver through the porta hepatis. In liver, it divides into : LT portal vein: Smaller, more anterior, more cranial. RT portal vein: Larger, more posterior, more caudal. On US PV is visualized on transverse plane lying anterior to the IVC. Size: Equal or less than 13mm. Affected by: Valsalva maneuver, respiratory changes, and PHT. Hepatopetal: flow towards liver (above baseline) Hepatofugal: flow away from liver (below baseline) Normal- Low velocity, hepatopetal, monophasic flow with subtle phasicity. PV – Provides 75% of the liver’s blood flow and run transversely and cranially. Note- With deep inspiration: PV, SV ,and SMV’s diameter increases. With CHF and fluid overload , PV Doppler shows pulsatility and with PHT it looses phasicity. Portal Vein sonographic features. Tubular structures Bright echogenic walls( due to collagen) Branch horizontally Oriented toward “porta hepatis” Larger as they get closer to ports hepatis NL Portal vein Doppler Portal Vein Occlusion Causes: Thrombosis due to Hyper coagulation state Stagnant PV flow due to PV HT Inflammation; Pancreatitis, Appendicitis Tumor from: Liver Pancreas Splenic Vein Joins the superior mesenteric vein to form the main portal vein Courses posterior to the pancreas and crosses anterior to the superior mesenteric artery Demonstrates spontaneous phasic flow away from the spleen and towards the liver Increase in caliber with inspiration Splenic Vein: Courses medially from the splenic hilum and runs post. and inf. to body & tail of the pancreas joins the IMV, before meeting the SMV. Superior Mesenteric Vein: Post. to the neck of panc. but ant. to the Uncinate process (A small extension off head of panc.). Seen parallel to the aorta and to the rt. of the SMA. It courses inf. to sup. drains small intestine and portions of large intestine (ascending, part of transverse colon). Splenic Vein Superior Mesenteric Vein Courses parallel to the superior mesenteric artery Demonstrates spontaneous phasic flow towards the liver Caliber will increase with inspiration and following a meal Gonadal Veins Right gonadal vein empties directly into the inferior vena cava Left gonadal vein empties into the left renal vein and occasionally the left suprarenal vein Lumbar Veins Branches of the common iliac veins Course lateral to the spine and posterior to the psoas muscles SMV Gonadal Veins/ovarian Gonadal Veins/Testicular Lumbar Veins LOCATION Abdominal Aorta Lies to the left of midline adjacent to the inferior vena cava Courses inferior and anterior in the abdomen to the level of the 4th lumbar vertebra (umbilicus) where it bifurcates into the right and left common iliac arteries. Lies anterior to the spine and psoas muscle Separated from the spine by 0.5 – 1.0 cm of soft tissue Inferior Vena Cava Lies to the right of midline adjacent to the abdominal aorta Formed at the level of the 5th lumbar vertebra at the junction of the right and left common iliac veins coursing superiorly in the abdomen to the right atrium of the heart Lies anterior to the spine, psoas muscle, crus of the diaphragm and right adrenal gland Lies posterior to the head of the pancreas Size Aorta The size of the normal abdominal aorta should not exceed 3 cm in diameter The aorta tapers as it courses inferiorly and measures approximately: Suprarenal: 2.5 cm Renal: 2.0 cm Infrarenal: 1.5 cm Common iliacs: 1.0 cm Inferior Vena Cava Usually measures less than 2.5 cm Decrease in caliber is demonstrated in inspiration and an increase in size when respiration is suspended. IVC SONOGRAPHIC APPEARANCE: Anechoic tubular structure Thin hyperechoic wall margins Internal vascular flow Aorta demonstrates a high resistance multiphasic parabolic flow pattern Inferior vena cava demonstrates spontaneous phasic flow and multiphasic pulsatile flow as it nears the diaphragm Technique Preparation Preparation for the abdominal vasculature is typically nothing by mouth 6-8 hours prior to the examination. Examination Technique Use the highest frequency abdominal transducer possible to obtain optimal resolution for penetration depth Proper focal zone and depth placement Decrease in dynamic range Proper Doppler controls (PRF, gain, wall filters) Evaluation and documentation of the abdominal aorta, common iliac arteries and inferior vena cava in the sagittal and transverse planes Evaluation and documentation of the maximum diameter of the abdominal aorta, common iliac arteries and inferior vena cava Duplex evaluation and documentation of any additional vascular structures requested Duplex evaluation, documentation and measurement of any abnormality should be included. If intraluminal thrombus is present, measurement of the vessel lumen should be included Indications for Examination Pulsatile abdominal mass Family history of abdominal aortic aneurysm Hypertension Abdominal pain Lower back pain History of arteriosclerosis Severe post prandial pain DVT? Pulmonary embolism Liver disease Evaluate mass from previous medical imaging study (i.e. CT) ABDOMINAL ARTERIAL PATHOLOGY ARTERIAL PATHOLOGY DESCRIPTION Aneurysm Weakening of the arterial wall All layers of the artery are stretched but intact Rare in patients under 50 years Male prevalence 5:1 Growth rate of 2mm /year is average and considered normal up to 5 mm/year Exceeds 3.0 cm in diameter for the abdominal aorta Exceeds 2.0 cm in diameter for the common iliac artery Exceeds 1.0 cm in diameter for the popliteal artery Twenty five percent of popliteal aneurysms are associated with an abdominal aortic aneurysm ARTERIAL STENOSIS NARROWING OR CONSTRICTION OF AN ARTERY CAUSED BY ATHEROSCLEROSIS, ARTERIOSCLEROSIS OR FIBROINTIMAL HYPERPLASIA Arteriosclerosis Pathologic thickening, hardening and loss of elasticity of the arterial walls Atherosclerosis Disorder characterized by yellowish plaques of lipids and cellular debris in the inner layers of the arterial walls Pseudoaneurysm Dilatation of an artery caused by damage to one or more layers of the artery as a result of trauma or aneurysm rupture ANEURYSMS OF THE ABDOMINAL AORTA ANEURYSM ETIOLOGY CLINICAL FINDINGS SONOGRAPHIC FINDINGS DIFFERENTIAL CONSIDERATIONS Abdominal Aortic Aneurysm Arteriosclerosis – most common Infection Asymptomatic Pulsatile abdominal mass Back and/or leg pain Abdominal pain Typically fusiform shaped dilatation of the aorta Saccular dilatation of the aorta may be demonstrated Diameter of 3 cm or greater Vessel becomes tortuous Wall calcifications Intramural thrombus Lymphadenopathy Retroperitoneal tumor Dissection DISSECTING ANEURYSM EXTENSION OF A DISSECTING THORACIC ANEURYSM HYPERTENSION MARFAN’S SYNDROME IDIOPATHIC PREGNANCY SHARP CHEST OR ABDOMINAL PAIN AUDIBLE BRUIT THIN HYPERECHOIC MEMBRANE WITHIN THE AORTA MEMBRANE FLAPS WITH ARTERIAL PULSATIONS DOPPLER DEMONSTRATES OPPOSITE FLOW DIRECTION BETWEEN THE MEMBRANE DURING DIASTOLE CHRONIC INTRALUMINAL THROMBUS POST SURGICAL REPAIR ECTATIC ANEURYSM WEAKENING OF ASYMPTOMATIC THE ARTERIAL WALL DILATATION OF THE AORTA WHEN COMPARED WITH A MORE PROXIMAL SEGMENT DILATATION MEASURES LESS THAN 3 CM IN DIAMETER TORTUOUS ARTERY TECHNICAL ERROR MYCOTIC ANEURYSM BACTERIAL INFECTION ASYMPTOMATIC ABDOMINAL PAIN PULSATILE ABDOMINAL MASS TYPICALLY SACCULAR SHAPED DILATATION OF THE AORTA ASYMMETRICAL WALL THICKENING LYMPHADENOPATHY RETROPERITONEAL TUMOR INTRAMURAL THROMBUS PSEUDOANEURYSM TRAUMA TO THE ARTERIAL WALL PERMITS THE ESCAPE OF BLOOD INTO THE SURROUNDING TISSUES MOST COMMON COMPLICATION OF AN AORTIC GRAFT PULSATILE MASS FLUID COLLECTION COMMUNICATING WITH AN ARTERY DOPPLER WILL DEMONSTRATE TURBULENT SWIRLING BLOOD FLOW WITHIN THE FLUID COLLECTION TO AND FRO BLOOD FLOW PATTERN IS DEMONSTRATED IN THE NECK OF THE ANEURYSM HEMATOMA LYMPHADENOPATHY ANEURYSM ARTERIOVENOUS FISTULA RUPTURED ANEURYSM RISK OF RUPTURE WITHIN 5 YEARS 5 CM = 5% 6 CM = 16% 7 CM = 75% SEVERE ABDOMINAL PAIN SEVERE GROIN PAIN HYPOTENSION NORMAL AORTIC SIZE ANEURYSM MAY STILL BE VISUALIZED ASYMMETRICAL OR UNILATERAL PARA-AORTIC HYPOECHOIC MASS “VEIL APPEARANCE” OVER THE AORTA AND SURROUNDING STRUCTURES FREE FLUID IN THE PERITONEAL CAVITIES LYMPHADENOPATHY CHRONIC INTRALUMINAL THROMBUS SURGICAL REPAIR PREVIOUS HISTORY OF ANEURYSM ASYMPTOMATIC ABDOMINAL OR LOWER BACK PAIN ANECHOIC SPACE BETWEEN THE GRAFT AND REPAIRED AORTA HYPERECHOIC PARALLEL ECHOES ALONG THE ARTERIAL WALLS DISSECTION RUPTURE ANEURYSM CHRONIC INTRALUMINAL CLOT RETROPERITONEAL PATHOLOGY ABDOMINAL VENOUS PATHOLOGY VENOUS PATHOLOGY Arteriovenous Shunts (AV Fistula) ETIOLOGY Trauma Congenital Surgery Inflammation Neoplasm CLINICAL FINDINGS Presence of a bruit or “thrill” Lower back or abdominal pain Edema Hypertension SONOGRAPHIC FINDINGS Doppler Demonstrates: Pulsatile flow within the vein Increase in arterial flow proximal to site of shunting Decrease in arterial flow distal to site of shunting Turbulent waveform with high velocities in both the artery and vein DIFFERENTIAL CONSIDERATIONS Tortuous vessel Stenotic vessel ENLARGEMENT CONGESTIVE HEART ASYMPTOMATIC FAILURE EDEMA THROMBOSIS INFILTRATING NEOPLASM INFERIOR VENA CAVA EXCEEDING 3.7 CM IN DIAMETER MAIN PORTAL VEIN EXCEEDING 1.3 CM IN DIAMETER SPLENIC OR SUPERIOR MESENTERIC VEIN EXCEEDING 1.0 CM INTRALUMINAL MEDIUM TO LOW LEVEL ECHOES SEEN WITH NEOPLASMS OR THROMBUS EXTRINSIC COMPRESSION ARTERIOVENOUS SHUNTING PORTAL HYPERTENSION TECHNICAL ERROR INFILTRATING NEOPLASM RENAL CARCINOMA ASYMPTOMATI C EDEMA INTRALUMINAL MEDIUM TO LOW LEVEL ECHOES VENOUS THROMBOSIS PRIMARY CAVAL TUMOR TECHNICAL ERROR Primary Caval Neoplasm Leiomyosarcoma is most common Asymptomatic Edema Intraluminal medium to low level echoes Infiltrating tumor Venous thrombosis Technical error Thrombosis Extension of thrombus from femoral, iliac, renal, hepatic or gonadal veins Asymptomatic Edema Intraluminal medium to low level echoes Infiltrating tumor Primary caval tumor Technical error
