1. Abdominal Vascular Ultrasound
Renal Duplex Sonography
Stephanie McDaniels BSRT (R),RDMS,RVT

2. Hypertension
Definition: chronic medical condition in which the blood pressure is elevated
Primary or essential: 90-95%--no medical cause can be found
Secondary: is a result of another condition, such as kidney disease or tumor (pheochromocytoma)
renovascular disease most common cause
Malignant hypertension : complication of hypertension characterized by very elevated blood pressure, and organ damage in the eyes, brain, lung and/or kidneys; at a high risk for development with history of secondary hypertension

3. Hypertension Strokes Heart attacks Heart failure Arterial aneurysm
Leading cause of chronic renal failure

4. Clinical Findings in Renovascular Hypertension
Hypertension that is difficult to control with medical treatment
Hypertension associated with renal failure or progressive renal insufficiency
Severe hypertension (diastolic blood pressure >120 mm Hg)
Onset of hypertension before age 30 or after age 50
Abrupt onset of hypertension
Generalized atherosclerosis
Negative family history of hypertension
Abdominal bruit

5. Renovascular Disease
Definition: a progressive condition that causes narrowing or blockage of the renal arteries or veins
renal artery occlusion: can be due to tumor, embolism ect.
renal vein thrombosis : vein becomes occluded
renal atherosclerosis: build-up of fatty material
causing renal artery stenosis
Can be partial or complete

6. Renal Artery Atherosclerosis
Risk Factors:
diabetes
family history of the condition
heart disease
high blood pressure
high cholesterol
obesity
smoking

7. Renal Artery Atherosclerosis
66 % of renovascular disease
atrophy of the affected kidney
renal failure if not treated
Most often occurs in proximal renal artery (ostium)

8. Fibromuscular Dysplasia
Definition: disease that can cause stenosis of arteries in the kidneys, the carotid arteries, and less commonly, the arteries of the abdomen
medial dysplasia most common presentation
characterized by alternating regions of thick and thin fibromuscular ridges containing collagen along the media
nonatherosclerotic, noninflammatory arterial changes
Up to 5% of the population

9. FMD Presents as hypertension Affects mainly women
Between 14 and 50 years of age
75% of all patients have disease in the renal artery
Patients often have infarcts to the kidney, gut and/or liver
Usually occurs in mid to distal segment of renal artery
Can also occur in intersegmental and arcuate arteries
Definitive diagnosis is made by angiography

10. Fibromuscular Dysplasia
Angiogram demonstrates
String of Pearl sign indicating
Fibromuscular dysplasia

11. Fibromuscular Dysplasia
Transverse color Doppler of the Aorta(A) and the right renal artery shows normal appearance of flow at the origin of the right renal artery but a
marked disorganization
of flow mid renal artery

12. Renal artery stenosis caused by fibromuscular dysplasia in a 43-year-old woman who had severe hypertension. (A) Color Doppler image reveals aliasing in the middle third of the right main renal artery (arrows), a typical location for stenosis caused by fibromuscular dysplasia. Aorta (A). (B) Intraparenchymal renal artery waveform demonstrating delay in systolic acceleration. AT = 120 ms. (C) Increasing the sweep speed widens or magnifies the tracing, making it easier to accurately measure AT and AI. (D) MRA demonstrates beading (arrow) of the middle third of the right main renal artery consistent with the diagnosis of fibromuscular dysplasia.

13. Treatment
Objective: restoration of blood flow to affected kidney
Percutaneous transluminal renal artery angioplasty (PTRA) : preferred treatment
cure in about 58% of patients
improvement in 35%
failure in 7%.
Vascular stent
Surgical bypass-last resort

14. Percutaneous Transluminal Angioplasty
Angiogram showing bilateral renal artery stenosis

15. Percutaneous Transluminal Angioplasty
After percutaneous transluminal angioplasty (right renal artery)
After percutaneous transluminal angioplasty and stent placement (left renal artery).

16. Embolism
Acute Renal Artery Occlusion
Definition: is a sudden, severe blockage of the artery that supplies blood to the kidney
atheroembolic disease may be responsible for 5-10% of acute renal failure in hospitals
can occur after injury or trauma
most patients are middle-aged
Have varied chronic underlying diseases
hypercoagulable states
mitral valve stenosis
atrial fibrillation

17. Symptoms persistent abdominal pain fever nausea vomiting anorexia
back or flank pain
hematuria

18. Diagnosis MRI Doppler Sonography Nuclear Captopril scan CT scan
Angiogram

19. Imaging Tests for Diagnosis of Renal Artery Stenosis or Occlusion
Advantages
Disadvantages
CT angiography
Noninvasive
Fast
Generally available
Requires IV iodinated contrast, which may be nephrotoxic
MR angiography
Highly accurate
Noninvasive
Safe in patients with GFR > 60 mL/min and possibly GFR 30—60 mL/min
Requires gadolinium contrast, which increases risk of nephrogenic systemic fibrosis
Doppler ultrasonography
Noninvasive, highly accurate
Provides information about renal function
Operator-dependent, time-consuming, and not always available; limited accuracy in obese patients
Radionuclide renography
Noninvasive; images renal blood flow
More accurate in unilateral than in bilateral stenosis; more accurate when captopril is used; at least 10% false-positive and false-negative rates, even when captopril
Arteriography
Diagnostic gold standard
Provides anatomic detail for surgical and invasive radiologic procedures
Invasive
Risk of atheroembolism (due to arterial catheterization) and contrast-induced nephropathy
Digital subtraction angiography
Noninvasive
Uses less iodinated contrast than arteriography
Requires iodinated contrast, but in smaller amounts than arteriography

20. Acute Renal Infarction
27-year-old woman with acute renal infarction. (A-B) Angiogram shows ovoid filling defect (arrow) in a segmental branch of the left renal artery in the lower pole, consistent with thrombus.

21. Renal Size in Acute Renal Embolism
Smaller right renal
Normal left renal
Patient presenting with BP of 230/129 and increased serum creatinine
History of severe right flank pain two week prior

22. A renal angiogram revealed a completely occluded right renal artery

23. Cholesterol Emboli Syndrome
Common complication of arteriography, vascular surgery, thrombolysis, and anticoagulation in elderly patients
dislodging atherosclerotic plaques particularly after mechanical instrumentation
Fragments of cholesterol plaques break off and circulate
Highly inflammatory, particularly in microvasculature, produce vasculitis-like reaction
Initial presentation: acute renal failure

24. Embolic syndrome

25. Renal Vein Occlusion
usually a result of vein thrombosis
is generally a complication of some other condition, but it may also occur as a primary event
The reaction of the kidney to its vein occlusion is determined by:
the balance between the acuteness of the disease vs
extent of the development of collateral circulation,
whether one or both kidneys are involved
Chronic or Acute

26. Etiology
Thrombosis of the inferior vena cava with secondary involvement of the renal veins
Hypovolemia
Primary renal disease: nephrotic syndrome by virtue of it being a hypercoagulable state is associated with an increased incidence of arterial and venous thromboemboli
Occlusion of renal veins by extrinsic or intrinsic involvement of the renal vascular pedicle
Systemic disease usually associated with a hypercoagulable state
Trauma

27. Symptoms
Directly related to the etiology of the occlusion and the response to renal venous hypertension
rapidity of the venous occlusion and the development of
venous collateral circulation determine the clinical presentation and resultant renal function
Acute: the affected kidney rapidly increases in size due to rapid congestion
Chronic : renal infarction and atrophy ensue and kidney size progressively shrinks.

28. Renal Vein Thrombus
Left Renal intraluminal thrombus with only partial occlusion

29. Renal Vein Thrombosis Native kidney Transplant kidney
In renal vein thrombosis arterial flow in a native kidney is minimally altered
while in a renal transplant the arterial flow is to and fro and demonstrates
a pandiastolic flow reversal

30. Pseudoaneurysms Doppler characteristics
Almost exclusively caused by trauma
Biopsy
Blunt trauma with renal laceration (less common)
Infection
Doppler characteristics
Swirling pattern of internal blood blow
To and fro pattern
Often associated with arteriovenous fistula
Flow will progress from feeding artery to the pseudoaneurysm and then to a draining vein

31. Pseudoaneurysm
Post traumatic pseudoaneurysm:Color imagingrounded area with
a swirling pattern of intraluminal flow ; Pulsed Doppler shows
“to and fro” pattern that is often difficult to detect in renal pseudoaneurysms.

32. Pseudoaneurysm
Post blunt abdominal trauma imaging demonstrated a hematoma as a
complex fluid collection (arrows) with a pseudoaneurysm seen as a cyst like
structure at the periphery of the kidney (arrowhead)

33. Arteriovenous Fistula
Generally occurs from trauma
Percutaneous needle biopsy most common cause
Generally are small and resolve spontaneously
Large AV fistulas rare and can cause
High output cardiac failure
Renal ischemia
Renal hypertension
Persistent fistulas may be embolized

34. Arteriovenous Fistula
Color Doppler US image
demonstrates a highly vascular lesion.
Color duplex Doppler image
shows the classic
waveform of
an arteriovenous fistula
with high velocities
and low impedance.

35. Renal Artery Aneurysm Symptoms:
Definition: dilated segment of renal artery that exceeds twice the diameter of a normal renal artery
5.04 ± 0.74 mm on ultrasound
Symptoms:
Hypertension 90% patient reporting symptoms
pain %
hematuria
renal infarction
may be asymptomatic

36. Renal Artery Aneurysm May be located: Extraparenchymal –85 %
roughly 70% are saccular
20% are fusiform
10% are dissecting
Intraparenchymal—15 %
20% present with bilateral
30% have multiple aneurysms

37. Intervention Rupture Symptomatic RAA
Hypertension
Pain
Renal ischemia or infarction secondary to embolization from the aneurysm sac
Renal artery aneurysms in females who are pregnant or in those contemplating pregnancy
Diameter greater than 2 cm
Enlarging RAA
RAA associated with acute dissection

38. R.A.A. Magnetic resonance imaging of a patient with
2 left renal artery aneurysms.
Both are saccular, one is at a
segmental branch (closed arrow)
and the other is intrarenal (open arrow).
Of note: this patient
also has a congenital absence
of the right kidney.

39. Aortogram with calcified left renal artery aneurysm (RAA)
Aortogram with calcified left renal artery aneurysm (RAA). (B-C) Same RAA in magnified view, demonstrating the RAA is saccular, arising from the main renal artery.

40. Vascular Anatomy
Right Renal Artery arises anterolateral from the aorta
Left Renal Artery usually lateral or posterolateral
RRA passes posterior to the IVC
The only major vessel posterior to the IVC
Origin of both renal arteries are slightly caudad to the SMA (good landmark)

41. Renal artery origin
abdominal aorta and origin of both renal arteries

42. Banana Peel Sign
The patient is asked to lay in left lateral decubitus position and relax the abdominal muscles. The probe is placed in a sagittal view in the soft part of the abdomen below the rib cage. Obtain the aorta and IVC in long axis. Usually, a portion of the right lobe of the liver is visible at the top of the image. By slightly varying the probe angle, both renal arteries can be seen arising from the aorta. The right renal artery will course toward the probe and the left will course away. This is an excellent view for obtaining a Doppler signal from each renal artery origin as well as the abdominal aorta

43. Segmental renal artery (at hilum)
Vascular Anatomy
Main renal artery
Segmental renal artery (at hilum)
Interlobar arteries (at corticomedullary junction)
Arcuate arteries (top of renal pyramids)
Interlobular arteries (subdivide into the afferent glomerular arterioles)

44. Renal Vascular Anatomy

45. Accessory Renal Arteries
Supernumery arteries
30% of individuals have more than a single renal artery on each side
may occur unilaterally or bilaterally
usually are smaller in caliber than the main renal artery
most arise from the abdominal aorta near main artery origin
also originate from the common iliac, superior or inferior mesenteric, adrenal, and right hepatic arteries
Early division of the main renal artery occurs in about 15% of the population.

46. Accessory Renal Arteries
May arise from aorta, above or below the main renal arteries.
On the right side, they may pass anterior to IVC.
They may also arise from the SMA or iliac arteries.

47. Supernumery Arteries

48. Supernummery Arteries

49. Renal veins The renal veins empty into the IVC
Located anterior to each renal artery
The left renal vein courses between the SMA and the abdominal aorta
5 % retro aortic position
Left renal vein is longer then Right renal vein
The right renal vein courses directly to the IVC from the renal hilum
Renal vein flow is phasic; however, some pulsatility may be encountered due to the proximity to the heart

50. Renal Veins Right Kidney and
Right Renal Vein draining into IVC
Left Renal Vein passing anterior to aorta and posterior to SMA (arrow)

51. Retroaortic left renal vein
Left renal vein from left renal hilum travelling behind Aorta (A) before reaching the IVC (C)

52. Nutcracker Syndrome compression of the left renal vein between
the abdominal aorta
and SMA.
The popular name
"nutcracker syndrome“
derives from the fact that,
in the sagittal view, the SMA
and AA (with some imagination)
appear to be a nutcracker crushing a nut (the renal vein).

53. Duplex Imaging

54. Duplex Imaging
Direct Imaging: visualization of main renal arteries with duplex evaluation
Indirect Imaging: evaluation of intrarenal waveforms