Aorta and Arteries

,<u Table 31 ■ Classification of sonographic findings by etiology

Anomalies Traumatic and postoperative lesions

Duplications False aneurysm (p. 195)

Arterial variants (p. 194) Arteriovenous fistula (p. 195)

Arterial prosthesis (p. 195)

Sequelae of hypertension and atherosclerosis Displacement, compression, infiltration

Aortic or arterial elongation (p. 197) Benign masses (p. 200)

Aortic ectasia (p. 197) Malignant masses (p. 200) Aortic or arterial stenosis (p. 197) Aneurysms (p. 198)

Anomalies n Duplication anomalies: renal artery (Fig. 255), rarely the aorta n Arterial variants:

• Renal arteries: course anterior (usually posterior) to the vena cava

- Left gastric artery arises from the superior mesenteric artery or from the aorta ("hepatosplenic trunk")

- Common origin of the superior mesenteric artery and celiac trunk ("celiaco-mesenteric trunk," Figs. 256 and 257)

• Aorta: may show an oblique or transverse course as a result of spinal scoliosis

Fig. 255a, b Duplicated renal artery. a Longitudinal scan: two arterial cross-sections (arrows) are visible behind the vena cava (VC). b Transverse scan through the right upper abdomen. CDS demonstrates both renal arteries (A). The possibility of duplication should always be considered when renal artery stenosis is suspected

Celiacomesenteric Type
Fig. 256 Variants of the celiac trunk (after Netter)

Fig. 257 Atypical origin of the superior mesenteric artery (SMA) from the celiac trunk (TR): celiacomesenteric trunk. V = superior mesenteric vein

n Pseudoaneurysm (false aneurysm) (Fig. 258): most commonly results from puncture of the femoral artery; arterial wall defect with pulsatile blood jets into the adjacent tissue. CDS: systolic-diastolic "to and fro" pulsed Doppler waveform

• Treatment: graded groin compression under CDS guidance is usually successful in closing the leak (alternative: adhesive).

n Arteriovenous fistula: Abnormal communication between a high-resistance artery and a low-resistance vein without an intervening capillary bed (Figs 259, 260).

n Arterial prosthesis (see Fig. 279a), p. 205, and Fig. 281a, p. 206):

• Smooth, straight echogenic structure (polyethylene), occasionally with a finely meshed texture (Dacron)

• Rare: periprosthetic infection or hematoma due to leakage. An irregular, hypoe-choic structure can be seen around the prosthesis.

Doppler After Aortofemoral Dacron
Fig. 258a, b Heavily thrombosed pseudoaneurysm (A) of the femoral artery (FA) following percutaneous catheterization. a Residual flow (blue, arrows). b Arterial Doppler signal (red). FV = thrombosed femoral vein
Femoral Fistula Doppler

Fig. 259a, b Arteriovenous fistula of the cubital artery and vein (A, V). a B-mode image with spectral analysis demonstrates a fistulous connection between the artery and vein. The sampled spectral waveform shows an arterial signal at the fistula site.

b CDS directly defines the fistula (F) and shows a turbulent pattern in the vein (blue-red)

Fig. 259a, b Arteriovenous fistula of the cubital artery and vein (A, V). a B-mode image with spectral analysis demonstrates a fistulous connection between the artery and vein. The sampled spectral waveform shows an arterial signal at the fistula site.

b CDS directly defines the fistula (F) and shows a turbulent pattern in the vein (blue-red)

Fistula Waveform

Fig. 260a, b Arteriovenous fistula (F). a From the superficial femoral artery (SFA) to the femoral vein (FV) following a shrapnel injury. The patient presented clinically with signs of left heart failure, which resolved after closure of the fistula. b Between the femoral artery (AF) and the greater saphenous vein (GSV) after catheterization showing a turbulent yellow-blue-red pattern in the fistula. VF = femoral vein

Fig. 260a, b Arteriovenous fistula (F). a From the superficial femoral artery (SFA) to the femoral vein (FV) following a shrapnel injury. The patient presented clinically with signs of left heart failure, which resolved after closure of the fistula. b Between the femoral artery (AF) and the greater saphenous vein (GSV) after catheterization showing a turbulent yellow-blue-red pattern in the fistula. VF = femoral vein n Aortic or arterial elongation (Figs. 261 and 262): Tortuosity and kinking may develop as an adaptive response to pressure. n Aortic ectasia (see Fig. 261): dilatation of the aorta to 25-30 mm (often with an associated aneurysm) n Aortic and arterial sclerosis (Fig. 263; see also Fig. 261):

• Vascular stenosis resulting from lipid-containing atheromatous wall lesions

• Complicated atherosclerotic plaques: protuberant, calcified sites of luminal narrowing (see p. 201)

Fig. 261 Elongation, ectasia, and sclerosis of the aorta. The aorta is slightly elongated and presumably has undergone marked lateral kinking because its full length cannot be visualized (a similar pattern is seen with spinal curvature). The aorta is markedly ectatic (cursors) and shows echogenic wall sclerosis with associated acoustic shadows

Aorta Elongated

Fig. 262 Tortuosity of the aorta (AO) secondary to hypertension and atherosclerosis. Arrows: atherosclerotic lesions

Aorta Elongated

Fig. 263a-d Atherosclerosis and stenosis. a Protuberant plaque in the aorta (AO, arrow) with luminal narrowing and atherosclerotic wall irregularities. b Iliac artery stenosis. B-mode image shows high-grade narrowing of the proximal iliac artery (arrow). c Iliac artery stenosis. CDS demonstrates the stenosis (arrow). Zones of color reversal indicate turbulent flow. d Stenosis (arrow) of the femoral artery. CDS shows prestenotic color change and turbulence. The high-grade luminal narrowing is caused by a calcifying plaque with an associated acoustic shadow (S)

Fig. 263a-d Atherosclerosis and stenosis. a Protuberant plaque in the aorta (AO, arrow) with luminal narrowing and atherosclerotic wall irregularities. b Iliac artery stenosis. B-mode image shows high-grade narrowing of the proximal iliac artery (arrow). c Iliac artery stenosis. CDS demonstrates the stenosis (arrow). Zones of color reversal indicate turbulent flow. d Stenosis (arrow) of the femoral artery. CDS shows prestenotic color change and turbulence. The high-grade luminal narrowing is caused by a calcifying plaque with an associated acoustic shadow (S)

n Aneurysms (Figs. 264-268; see also Figs. 276-278, p. 204): • Types of aneurysm (Fig. 264):

- Berry (pouch-)shaped

- Saccular

- Fusiform (spindle-shaped)

- Dissecting

False Aneurysm True Aneurysm
Fig. 264 Types of arterial aneurysm. a True aneurysms, saccular or fusiform (2) and berry (pouch-)shaped (1). b Dissecting aneurysm. c Pseudoaneurysm (or false 198 aneurysm)

n Note: A dissecting aneurysm may occur without luminal enlargement.

- False aneurysm ("pulsating hematoma"; see above)

- Arteriovenous fistula without luminal enlargement; see above Sonographic criteria:

- Circumscribed or diffuse dilatation (aorta >30 mm)

- Atherosclerotic plaques (see p. 203)

- Thrombi

Aortic Aneurysm Sonographic Appearence
Fig. 265a, b a Serpentine aneurysm (cursors, AN) arising from a normal-sized aorta (AO) and forming a largely asymmetrical series of dilatations. b CDS appearance of a typical small, asymmetrical anterior wall protrusion (arrow)

"O

Pulsating Fistulas

Fig. 266a, b Dissecting aneurysm. a Intraluminal echogenic intima (arrows). b TEE demonstrates the intimal flap in the aortic lumen of the thoracic aorta, longitudinal scan

Aortic Aneurysm Sonographic Appearence

Fig. 267a-c "Aneurysmosis" involving all of the infradiaphragmatic aorta with ectasia, thromboses, and apparent intimal dissection (prebifurcation, cranial?)

with a thin flap (arrow) extending into the gallbladder bed. 199

Fig. 267a-c "Aneurysmosis" involving all of the infradiaphragmatic aorta with ectasia, thromboses, and apparent intimal dissection (prebifurcation, cranial?)

with a thin flap (arrow) extending into the gallbladder bed. 199

Aortic Intimal Sarcoma

Fig. 268 Aneurysm (AN) of the right renal artery (RA) posterior to the vena cava (VC)

n Benign masses (such as cyst or abscess): These lesions tend to displace arteries rather than compress them. Infiltration does not occur. n Malignant masses (such as malignant lymphoma and carcinoma, Figs. 269, 270): Lymphomas tend to displace and compress vessels, whereas carcinomas infiltrate them.

Fig. 269 High-grade non-Hodgkin lymphoma of the pancreas (T) causing convex displacement and slight compression of the splenic artery. CDS shows no turbulence, indicating a small stenosis. AO = aorta

Ceiliac Artery Compression

Fig. 270 Inoperable pancreatic carcinoma (T) infiltrating the celiac trunk. CDS and spectral analysis show irregular vascular calibers and increased flow velocities > 240 cm/s.

Fig. 270 Inoperable pancreatic carcinoma (T) infiltrating the celiac trunk. CDS and spectral analysis show irregular vascular calibers and increased flow velocities > 240 cm/s.

Table 32 ■ Classification of sonographic findings by location

Wall changes jfl

Hypoechoic Echogenic ^

Thrombotic plaques (p. 201) Atherosclerotic plaques (p. 201)

Luminal changes

Hypoechoic Echogenic

Embolus (p. 203) Intimal flap, prosthesis (p. 205)

Thrombus (p. 204) Protuberant calcifying plaques (p. 205)

Floating thrombi (p. 204)

Combined changes (involving the lumen and wall)

Malignant Benign

Metastases (p. 205) Retroperitoneal fibrosis (p. 205)

Periprosthetic infection, anastomotic leak (p. 206)

n Atheromatous plaques (see Figs. 261 and 263, pp. 197 and 198). n Hypoechoic, protuberant intraluminal platelet thrombi (Figs. 271 and 272):

• Sessile or pedunculated, occasionally laminar

• Rarely with an echogenic cap, sometimes with associated intimal dissection.

Fig. 271 Protuberant intraluminal atheromatous plaques (arrows) with echogenic atherosclerotic wall thickening of the descending aorta (AO). TEE was used to locate the source of the emboli

Anastomotic Intimal Thickening

Fig. 272a, b Hypoechoic, protuberant thrombotic lesion filling the arterial lumen. a Protuberant atherosclerotic lesion of the aorta (AO) extending into the right iliac artery (IA). All criteria of atherosclerosis are present: significant bandlike wall thickening, luminal narrowing (arrows), a hypoechoic thrombus with a fibrous cap, a broad band of calcification, and an acoustic shadow (S). b Occlusion of the mesenteric artery (MA): absence of arterial flow. TR = thrombus

Fig. 272a, b Hypoechoic, protuberant thrombotic lesion filling the arterial lumen. a Protuberant atherosclerotic lesion of the aorta (AO) extending into the right iliac artery (IA). All criteria of atherosclerosis are present: significant bandlike wall thickening, luminal narrowing (arrows), a hypoechoic thrombus with a fibrous cap, a broad band of calcification, and an acoustic shadow (S). b Occlusion of the mesenteric artery (MA): absence of arterial flow. TR = thrombus n Echogenic wall thickening, complex wall thickening:

• Echogenic = calcification (see Fig. 263c), p. 198)

n Atherosclerotic plaques (Fig. 273): see classification in Table 33.

- Segmental or circumscribed wall thickening with no acoustic shadowing

- Echogenic plaques without calcification, cholesterol deposits

• Complicated plaques (Fig. 273; see also Fig. 272a, p. 202, and Fig. 271, p. 201): atherosclerotic plaques with calcification, necrosis, and ulceration (the latter cannot be detected sonographically)

Calcified Atherosclerosis The Aorta

Fig. 273a, b Atherosclerosis. a Simple atherosclerotic lesion of the aorta (AO). Atheromatosis: echogenic wall thickening without an acoustic shadow (arrows). b Complicated atherosclerotic lesion: slightly raised, echogenic lesion with significant wall thickening (arrows), a faint bandlike acoustic shadow, and irregular vessel contours

Fig. 273a, b Atherosclerosis. a Simple atherosclerotic lesion of the aorta (AO). Atheromatosis: echogenic wall thickening without an acoustic shadow (arrows). b Complicated atherosclerotic lesion: slightly raised, echogenic lesion with significant wall thickening (arrows), a faint bandlike acoustic shadow, and irregular vessel contours

Popliteal Calcification Images

Fig. 274a, b Monckeberg sclerosis. a B-mode image shows diffuse, patchy wall calcification (arrows) of the popliteal artery (PA) with partial acoustic shadowing (S). b CDS shows no significant stenosis. The patient had diabetic neuropathy with pedal ulcers and a palpable pedal pulse, Doppler pressure >300mmHg

Fig. 274a, b Monckeberg sclerosis. a B-mode image shows diffuse, patchy wall calcification (arrows) of the popliteal artery (PA) with partial acoustic shadowing (S). b CDS shows no significant stenosis. The patient had diabetic neuropathy with pedal ulcers and a palpable pedal pulse, Doppler pressure >300mmHg

Table 33 ■ Classification of atherosclerotic plaques

Simple plaques

Complicated plaques

Focal echogenic intimal thickening

Irregular surface, disruptions, ulceration,

(secondary) calcifications

Smooth protuberances < 5 mm

Protuberances extending > 5 mm into the lumen

- Sessile

- Pedunculated (prone to embolism)

n Mönckeberg sclerosis (Fig. 274): diffuse calcific deposits in the media of diabetic patients with symptoms of arterial occlusive disease (AOD) (severe occlusive symptoms are rare, however)

• Extremely high Doppler wedge pressures

• Diffuse, patchy echogenic wall calcification, sometimes with acoustic shadowing

n Embolus (Fig. 275): hypoechoic intraluminal flow void. B-mode imaging is less rewarding than CDS, which can confirm the absence of flow.

Fig. 275 Embolus (arrow) straddling the bifurcation of the aorta (AO). The patient presented clinically with acute bilateral leg pain and other manifestations of AOD

Nckeberg Ultrasound

Ifl n Conglutination thrombus in aortic or arterial aneurysms (Figs. 276-278):

• Eccentric or concentric, weakly echogenic material on the vessel wall

• Frequent lamination

• Doppler ultrasound occasionally shows an anechoic crescent devoid of flow n Floating thrombi, "erythrocyte noise": pulsating, swaying hypoechoic structure or erythrocyte clusters in slow-moving flow

Saccular Aortic Aneurysm

Fig. 276 Circumferential thrombus (arrows) in an aortic aneurysm. CDS shows color reversal indicating zones of turbulent flow

Fig. 277 Saccular aneurysm: circumferential thrombosis surrounding a central residual lumen (AO). The aneurysm occludes the proximal portions of the iliac arteries (IA). Typical features: size > 10 cm, balloon-like shape fi-71 jfa- _____

Fig. 278a, b Conglutination thrombi in a saccular aortic aneurysm, visualized in upper abdominal transverse scans. a Peripheral laminar thrombus (TH) and a central whorled thrombus (arrows) with a crescent-shaped, anechoic residual lumen. Both are enveloped by an echogenic intimal flap (dissecting aneurysm). b Scan at a more distal level shows a regular central aortic lumen (AO) alternately surrounded by conglutination thrombi and serosanguinous fluid (S)

n Intimal flap (see Fig. 266, p. 199): e.g., in aortic dissection

• Hyperechoic intraluminal membrane, usually showing an irregular thickness n Intraluminal aortic prosthesis (Fig. 279): smooth, echogenic intraluminal membrane n Protuberant echogenic plaques (see Fig. 263), p. 198; Fig. 274, p. 203)

Protuberant Thrombus

Fig. 279a, b Intraluminal aortic prosthesis and intimal dissection. a Intraluminal aortic prosthesis: fine, echogenic intraluminal walls of the prosthesis in an aortic aneurysm (41 mm in diameter, cursors). b Almost identical intraluminal structure as in a. The entry tear of the intimal dissection (arrows) can be identified

Fig. 279a, b Intraluminal aortic prosthesis and intimal dissection. a Intraluminal aortic prosthesis: fine, echogenic intraluminal walls of the prosthesis in an aortic aneurysm (41 mm in diameter, cursors). b Almost identical intraluminal structure as in a. The entry tear of the intimal dissection (arrows) can be identified

Pa n Metastases, lymphadenopathy (Fig. 280; see also Fig. 658, p. 438; Fig. 152, p. 112; Fig. 158, p. 115):

• Well-defined masses or bulky, hypoechoic perivascular structures

• Increased aorto-spinal distance (> 5 mm)

• Sandwich sign (vessel "sandwiched" between conglomerates of lymph nodes, suggestive of high-grade lymphoma)

Fig. 280a, b Differentiation of an aortic aneurysm from a perivascular tumor. a Initial sonographic diagnosis: dissecting aortic aneurysm (AO, AO A) with an intimal flap (IN). b CDS: anechoic lymphomatous tumors (T) around the aorta and vena cava (AO, VC). The renal artery (RA) passes through the tumor masses. Diagnosis: high-grade NHL

n Retroperitoneal fibrosis:

• Diffuse, hypoechoic periaortic structures

• Usually associated with urinary tract obstruction 205 Schmidt, Ultrasound © 2007 Thieme

All rights reserved. Usage subject to terms and conditions of license.

m n Para-aortic or para-arterial abscess (see also Figs. 124 and 125, p. 95): hypoe-choic mass with irregular margins:

• Hypoechoic, irregular, bandlike structure surrounding the prosthesis

• Perivascular mass in the area of the prosthetic anastomosis, often manifesting arterial flow (by CDS).

n Graff infection, suture-line breakdown (Fig. 281a, b): hypoechoic mass surrounding the graff

Postoperative Infection UltrasoundInfected Suture Line

Fig. 281a, b Postoperative perivascular masses. a Infected popliteal prosthesis (arrows, AP) with extensive purulent material (cursors). The patient presented clinically with unexplained fever and suspected popliteal vein thrombosis. b Anastomotic leak (arrow) with a perivascular hematoma (H) following the insertion of an aortofemoral vascular prosthesis (P). FA = femoral artery

n Sonography: Ultrasound is a mainstay for the initial evaluation and postoperative follow-up of all aortic and arterial diseases.

• Classification of an aneurysm: according to type (true, dissecting, or false)

• Preoperative planning: Ultrasound aids in treatment planning based on the location (infrarenal, iliac) of an aortic aneurysm. The sonographic criteria for extension above the origins of the renal arteries are as follows:

- Direct visualization of the renal artery arising from the aortic aneurysm

- Superior border of the aneurysm is above a horizontal line drawn from the renal hilum to the aorta

Fig. 282a, b Sonographic determination of intima-media thickness in the common carotid artery. a Normal finding (0.6 mm) in a healthy 68-year-old man. b Intima-media thickness of 1.4 mm in a 53-year-old man with a high 206 cardiovascular risk profile

- The distance from the aortic bifurcation to the superior border of the aneu- g rysm is > 9.5 cm. "2

n New sonographic techniques: US contrast agents have been shown to be highly ^ effective in enhancing Doppler signals within the macrovasculature and the "J2 microvasculature. Contrast enhanced US increases the accuracy in detection of O abnormalities in periferal arteries and portal veins. ¡2

n Angiography: Other tests can reduce the need for conventional angiography but C cannot replace it. Angiograms are essential for preoperative planning and for selecting the optimum therapeutic procedure (catheter-directed thrombolysis ^ and atherectomy, stent graft, patch graft, operative thrombectomy). n MR angiography: has already become a standard tool for surveying the arterial vascular system to verify stenoses, especially in patients who are poor candidates for conventional angiography (renal failure). It can be particularly useful as a prelude to interventional angiography.

• Advantages: less contrast medium, single sitting

• Disadvantage: cannot adequately quantify stenoses n CT: Better than sonography for defining the extent of supradiaphragmatic aortic aneurysms and evaluating the dissection n Echocardiography: establishes the presence of a dissecting aneurysm (e.g., involving the aortic root) n Staged protocol for arterial studies:

• Vascular physical examination (palpable pulses, stress tests)

• Doppler examination with pressure measurement, determination of Doppler index

• Angiography n Procedure for aortic aneurysms:

• Diagnostic workup: begins with ultrasound, which may be done as a routine examination (lesion detected incidentally), a selective examination for suspected disease, or an emergency examination (dissection, perforation)

• Follow-ups: at 3-6 month intervals for aneurysms that do not require acute operative treatment (see below)

• Indications for operative treatment:

- Aneurysm size is the main criterion. Aneurysms < 5 cm have a 5-15 % likelihood of rupture within 5 years, and this increases to 75% for aneurysms

> 8 cm. Aneurysms > 5 cm should therefore be treated operatively.

- Another criterion is the sonographically determined growth rate. Aneurysms

> 5 cm grow by an average of 0.6 cm in 1 year, whereas smaller aneurysms grow by 0.2 cm. Rapid growth noted at 4-6-month ultrasound follow-ups strengthens the indication for early operative treatment.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook


Post a comment