Great Abdominal Vessels/ Adrenal Gland/ Renal Transplant

List clinical indications for performing an abdominal aortic sonogram

• Pulsatile abdominal mass

• Abdominal pain

• Abdominal bruit

• History of smoking

• Hemodynamic compromise in the lower limb arterial system

• Nausea and vomiting

What should be assessed on an abdominal aortic sonogram?

• Evaluate adjacent organs (kidneys or IVC)

• Check for patency

• Measurements (AP and trans)

• Visualize entire aorta and main branches

• Doppler

• Detect for stenosis, aneurysm, thrombosis, and dissections

What are normal measurements of the aorta and iliacs and how are they specifically measured?

• Aorta: men = <2.3 cm; women = < 1.9 cm

• Iliacs: men = 1.4 – 1.5 cm; women = 1.2 cm

• Outer to outer edge

What are objectives of Doppler when evaluating the aorta?

• Determine patency of entire aorta

• Branches with color Doppler

• Characterization of altered flow w/ spectral Doppler

• Detection of altered w/ color Doppler

• Determine high or low resistance in vessels.

Discuss and describe atherosclerosis, associations and possible complications

• Main cause of cardiovascular diseases; includes heart disease, cerebrovascular accident, hypertension, and peripheral vascular disease

• Atherosclerosis = accumulation of fat, complex carbs, blood, blood products, fibrous tissue, and calcium deposits

• Complications = thrombosis, infection, stenosis (graft kink, neointimal hyperplasia, atherosclerosis), and anastomotic pseudoaneurysm

Define and describe ectasia of the aorta

• Ectasia = diffuse dilation of a vessel, whereas an abdominal aortic aneurysm is a region of focal enlargement

• Ectasia occurs when aorta increases both in transverse diameter and in vertical length; causes distal aorta to “kink,” usually anterior and to the left

Discuss and describe aortic aneurysms, specific types and locations

• The abdominal aorta slowly tapers from diaphragmatic hiatus to aortic bifurcation

• Most common cause: atherosclerosis; cause dilation of aorta from walls from being weakened

• Two types of AAA: Saccular and Fusiform

• Most common location = infrarenal

Discuss and describe clinical findings associated with AAA

• Pulsatile mass

• Lower back pain

• Abdominal pain

• Leg pain

• Palpable

• Satiety

• Nausea and vomiting

• Calcified aorta on x-ray

What are complications associated with abdominal aortic aneurysm? Discuss each in terms of clinical and sonographic findings

• Complications: infection, stenosis (graft kink, neointimal hyperplasia, atherosclerosis), and anastomotic pseudoaneurysm

• Clinical findings = thrombosis, dissection, distal embolism, infection, obstruction, invasion adjacent structures, and branch artery stenosis

• Sonographic findings = generalized dilation of >3 cm, most AAAs deflect to the left side or kink anteriorly, mural thrombus, lateral walls are often indistinct.

What are criteria for surgical intervention of an abdominal aneurysm?

• Aorta >3 cm

• 1.5X normal size

• Lack of distal tapering

Discuss abnormalities associated with aortic dissection

• Dissection of aorta (Type II) may occur secondary to cystic medial necrosis (weakening of the arterial wall), to hypertension, or to the inherited disease Marfan’s syndrome

What are the clinical findings, and signs and symptoms of dissection?

• Clinical findings + Signs and Symotoms: vomiting, back/ arm pain, chest pain, leg pain, blindness, transient headache, and coma

List sonographic findings associated with dissection of the aorta

• Classic finding = visualization of flap at site of dissection

• An echogenic intimal membrane within aorta/ iliac arteries move freely w/ arterial pulsations on sonography if both the true and false lumen are patent

• If membrane is thick and lumen is thrombosed, the membrane may not move

Describe the various types of aortic endografts

• Graft may be anastomosed in an end-to-side or end-to-end manner

• Placed within aorta, at level of aorta and iliac artery, or within the femoral artery

• Further development in techniques has placed grafts in aortofemoral and juxtarenal positions

Discuss Doppler findings associated with aortic stenosis

• Increased velocity across obstructive membrane

• Color flow imaging = increased turbulence at area of narrowing

Discuss and describe splanchnic artery aneurysms, causes, signs and symptoms, and sonographic findings

• The splanchnic aneurysms may be atherosclerotic, posttraumatic, mycotic, congenital, or inflammatory

• The common causes = congenital, arteriosclerosis, trauma, infectious process, and inflammation

• Signs and symptoms = asymptomatic; may include abdominal pain, bleeding in either the GI tract or intra- abdominal, palpable, abdominal mass (not as common), and bruit

• Sono. findings = dilation of visceral arteries, affecting splenic, hepatic, superior mesenteric, and celiac arteries

Discuss and describe the most common complication associated with an aortic graft or prosthesis and the specific sonographic findings

• Complications of grafts = immediate endoleak formations, without outflow, and persistent

• Evaluation of graft, sonographer should look for

  stenosis at ends of graft, aneurysm formation, or pseudoaneurysm development

• Doppler evaluation of distal vessels should be conducted to ensure that adequate blood flow is available

• Fluid collections (i.e., hematoma, lymphocele, seroma, or abscess formation) may develop at the graft site

Discuss and describe a pseudoaneurysm and its sonographic appearance

• Develop following graft anastomosis, renal biopsy, or intratumoral hemorrhage (angiomyolipomas), or it may occur post renal surgery (partial nephrectomies) or post trauma; as with AVF, it is very rarely congenital

• Can appear round hypoechoic or cystic mass in renal parenchyma that fills with color signal on color flow Doppler imaging

Discuss changes in the IVC with respiration and normal Doppler patterns of the IVC

• The IVC is a highly compliant vessel, meaning its size and shape change with respiration due to pressure variations in the thorax and abdomen

• IVC collapses as venous return to heart increases but it also enlarges as venous return slows

• Doppler evaluation of the IVC shows a pulsatile, phasic, and respiratory-dependent flow pattern due to pressure changes from the heart and lungs

Discuss causes of obstruction of the IVC

• Caucasians = hypercoagulability

• Asians = membranous obstruction of IVC is most common cause

• Obstruction of the IVC can spread from another vein in the pelvis, lower limb, liver or kidney

Discuss the Hallmark of venous patency on sonogram

• Primary hallmark is to do compression maneuver, then follow with color Doppler evaluation, and spectral Doppler

• Sonographic findings = Patent vein evaluate for compressibility, spontaneous flow on spectral Doppler, phasicity with respiration, augmentation response, and color flow filling

Briefly review and discuss Budd-Chiari Syndrome and sonographic findings associated with it

• Budd-Chiari syndrome = occlusion of some or all of the hepatic veins/ IVC

• Sono findings: ascites, large liver, caudate lobe often sparred, hemorrhagic infarction may produce altered regional echogenicity

Discuss and describe the IVC filter

• Filter is placed in IVC to trap embolus from the lower extremities

Where is the right adrenal gland located in relation to the IVC & right kidney? Where is the left adrenal gland located in relation to the aorta & left kidney?

• Right adrenal gland = superior/ medial to right kidney, posterior to the IVC

• Left adrenal gland = superior/ medial to left kidney, adjacent to the aorta.

What hormones are secreted by the adrenal cortex and medulla?

• Adrenal cortex secretes corticosteroids; cortisol and aldosterone

• Adrenal medulla produces catecholamines like epinephrine and norepinephrine

List 2 indications for adrenal sonography in neonates. List 3 indications for adrenal sonography in adults

• Neonates = eval. adrenal hemorrhage and congenital adrenal hyperplasia

• Adults = assessment of adrenal masses, adrenal hypertension, and adrenal metastases

Describe the appearance & size of infant adrenal gland

• Larger than older infant or young child

• Each gland lies immediately above upper pole kidney

• Left adrenal gland extends medially than right

• Gland has inverted “V” or “Y” shape

• Adrenal medulla = thin, distinct echogenic stripe, surrounded by more prominent & less echogenic adrenal cortex

Discuss what adrenal hemorrhage is associated with, when does it usually occur, & clinical signs/ symptoms

• Associated = severe trauma or infection

• Occurs = more common in neonates with experienced traumatic delivery w/ stress, asphyxia, and septicemia

• Clinical signs/symptoms = abdominal mass, anemia, and hyperbilirubinemia

Discuss the cause, clinical presentation & appearance of adrenals in congenital adrenal hyperplasia

• Cause = recessive disease involving adrenocortical enzyme defect

• Clinical presentation = ambiguous genitalia, weight loss, and endocrine changes

• Appearance = testicular mass/enlargement and precocious puberty w/ or w/o salt-depletion syndrome

What is the 2nd most common abdominal tumor of childhood? At what age does it mainly occur? Where does it arise from? What syndrome associated with it? What is its sonographic appearance?

• Neuroblastoma

• B/t 2 months and 2 years

• Arise from: medulla of adrenal gland; also in the neck, mediastinum, retroperitoneum, and pelvis

• Sono Appear.: highly echogenic, intrinsic calcifications, smaller tumors = homogenous + hyperechoic whereas larger tumors = complex

Describe the different scan planes, patient positions & transducer placements used to obtain images of adult adrenal gland. Where is the right and left adrenal best evaluated from? What are the keys to identifying the right and left adrenal glands?

• Scan planes = transverse, coronal, and sagittal plane

• Positions = supine, oblique, and LLD

• Right and left adrenal best evaluated: right adrenal = RLD, left adrenal = LLD

• Identifying keys = location relative to the kidney and surrounding vessels.

What is the size & sonographic appearance of adult adrenal glands?

• Adrenal gland varies in size, shape, configuration

  > Normal size = < 3cm

• Right adrenal gland = triangular and caps the upper pole of right kidney

• Left adrenal gland = semilunar in shape and extends along medial border of left kidney from upper pole

• Sono appear.: hypoechoic to highly echogenic fat surrounding the gland

What are the most frequent infectious organisms to affect the adrenal gland?  Which ones are most commonly responsible for calcifications in the adrenal gland?  What is the sonographic appearance of the adrenal affected by TB?

• Turberculosis (TB), histoplasmosis, blastomycosis, meningococcal, echinococcal, cytomegalovirus, herpesvirus, and pneumocystis

• Responsible for calcification of adrenal gland = TB & histoplasmosis

• Sono appear.: depends on stage of of infection;

  > Chronic = atrophic + heavily calcified

  > Acute = enlarged, inhomogeneous caused by caseous necrosis

What are the two types of adrenal adenomas?  How does each present clinically?  What is the sonographic appearance of adrenal adenoma?

• 2 types: hyperfunctioning & non-functioning

• Clinical presentation:

  > Hyperfunction = symptoms related to excess hormone production, Cushing’s syndrome, or Conn’s disease

  > Non-functioning = asymptomatic; well-defined, round, slightly hypoechoic, homogenous mass

What is Cushing’s syndrome a result of?  What are the clinical features?  What adrenal abnormalities cause it?  How is Cushing’s disease different?

• Result of: Cushing's syndrome results from prolonged exposure to high levels of cortisol, often due to adrenal tumors or pituitary adenomas

• Clinical features: weight gain, hypertension, diabetes, “buffalo hump” and characteristic facial changes (“moon face”)

• Abnormalities causing it: adrenal adenomas or hyperplasia, while Cushing's disease specifically refers to pituitary-dependent causes

What is Conn’s disease a result of?  What are its clinical features?  What adrenal abnormalities cause it?

• Result of: primary hyperaldosteronism; excessive production of aldosterone by adrenal adenomas or hyperplasia

• Clinical features: hypertension, muscle weakness, and metabolic alkalosis

• Adrenal abnormalities cause: adrenal adenomas or bilateral adrenal hyperplasia

What is a pheochromocytoma?  What does it secrete?  What are its symptoms?  Other than in the adrenal, where can it arise?  How often are they malignant?  What disorders are they associated with?  What is its sonographic appearance?

• What is it: tumor of the adrenal medulla that secretes catecholamines (such as epinephrine and norepinephrine)

• Symptoms = hypertension, palpitations, sweating, and headaches

• Although primarily arising in the adrenal glands, it can also occur in extra-adrenal locations (e.g., sympathetic ganglia)

• Rarely malignant; ~10% of cases associated w/ genetic disorders like Multiple Endocrine Neoplasia (MEN) syndromes

• Sono appear.: well-defined + hypervascular masses

What is a myelolipoma? What is it composed of? At what age does it most commonly occur? What is their size range?  What is their sonographic appearance?

• What is it = rare, benign tumor

• Composed of: mature adipose tissue and hematopoietic elements

• Commonly occurs in: 5th or 6th decade

• Size range = < 5cm - 30 cm

• Sono appear.: homogenous/heterogenicity, isoechoic to hypoechoic and typically well-defined

What are the two types of adrenal cortical cancer?  Is it more common in males or females?  At what age does it most commonly occur?  What does it have a tendency to do?  What is its sonographic appearance?

• Two types: hyperfunctional or non-functional

• Females

• Age: 4th decade

• Tendency: highly malignant tumor and tends to invade adrenal vein, IVC, and lymphatics

• Sono appear.: heterogenous with central area of necrosis and hemorrhage

Where, in terms of frequency of site for metastatic disease, does the adrenal rank?  What are the most common primary cancers that metastasize to the adrenal?  What is the sonographic appearance?

• Frequency: 4th most frequent site for metastatic disease after the lungs, liver, and bone

• Common primaries: lung, breast, melanoma, kidney, thyroid, and colon

• Sono appear: heterogenous, central necrosis, hemorrhage, calcification (rare), heterogenous, and solid

 What may aid in distinguishing a liver or subhepatic mass from a renal or adrenal mass?

• Ultrasound can be superior to CT when a large mass is in the RUQ

How common are adrenal cysts?  Benign or malignant?  At what age is it most common?  Is it more common in males or females?  What are the symptoms?  What is the sonographic appearance?

• How common: rare benign lesions; most discovered incidentally

• Benign

• Age: any age; mostly 3rd - 5th decade

• Female

• Symptoms: asymptomatic

• Sono appear.: round/ oval, thin-smooth walls, and internal debris

What are the 2 basic types of kidney donors? Where is the donor kidney placed in the recipient?

• Types: family members or close friends w/ long standing relationship w/ recipient

• Location: right or left lower quadrant

Describe the renal transplant surgical procedure including types of vascular anastomoses that may be done & connection of ureter to bladder

• Right lower quadrant is selected b/c right iliac vein is more superficial and horizontal; facilitating creation of vascular anastomosis

• Cadaveric = anastomosed end to side to external iliac artery

• Live donor = end-to-end anastomosis to internal iliac artery; end to side external iliac artery

• Ureter: anastomosed superolateral wall of bladder; tunneling ureter thru bladder wall to prevent reflux of transplant

Discuss type & frequency of transducer used to evaluate renal transplant. What aspects of renal tx should be assessed on gray-scale imaging? What vessels are investigated using spectral Doppler? What is evaluated w/ power Doppler?

• Frequency & Transducer = high-frequency linear; 5-12 MHz

• Gray-scale:

Discuss normal & abnormal resistive indices (RI)

• RI 0.7 or less = good perfusion

• RI 0.7 - 0.9 = possible rejection

• RI >0.9 = rejection

List several things that can elevate RI in renal tx

• Acute tubular necrosis

• Infection

• Renal artery stenosis

• Renal vein thrombosis

• Collecting system obstruction

• Dehydration

• Systemic hypertension

What are the appropriate power Doppler settings for evaluating cortical perfusion in renal tx

• High gain

• Low color gain

• Low PRF

• Smallest scale should demonstrate peak velocity

• High frequency transducer

Where is the most frequent location of obstruction in renal tx pt? What are intrinsic & extrinsic causes of obstruction

• Frequent location =ureteropelvic junction (UPJ) or ureterovesical junction (UVJ)

• Intrinsic causes = strictures from iatrogenic injury, intraluminal lesions (ex. stones, blood clots, sloughed papillae), peri-graft fibrosis, and ureteral kinking

• Extrinsic causes = compression from surrounding structures, such as tumors or enlarged lymph nodes.

What is the most common vascular complication of renal tx? Clinically, when is renal artery stenosis suspected? What Doppler criteria suggests renal artery stenosis? What conditions may lead to a false-positive diagnosis of renal artery stenosis?

• Most common vas. complication = Renal artery stenosis

• Clinical suspicion =

What is the most common cause of renal artery thrombosis? What are other predisposing factors? What are the Doppler findings w/ renal artery thrombosis?

• Most common cause = hyperacute or acute rejection; occlusion of intraparenchymal arterioles

• Predisposing factors = young pediatric donor kidneys, atherosclerotic emboli, acquired renal artery stenosis, hypotension, vascular kinking, and hypercoagulable states venous flow distal to occlusion, within both hilar and intraparenchymal vessels

What are the risk factors for renal vein thrombosis? What are the clinical symptoms of renal vein thrombosis?

• Risk factors = technical difficulties at surgery, hypovolemia, propagation of femoral/ iliac thrombosis, and compression by fluid collections

• Clinical symptoms = acute pain, swelling of allograft, and abrupt cessation of renal function b/t 3rd and 8th postoperative day

What are the sonographic findings in renal vein thrombosis?

• Allograft appears enlarged

• (Rare) intraluminal thrombus may be dilate main renal vein or w/in intraparenchymal venous system

What are the most common cause of renal vein stenosis? What is the Doppler criteria for renal vein stenosis

• Common cause = perivascular fibrosis or external compression by adjacent fluid collection

• Color Doppler = aliasing due to high-velocity turbulent flow

• Spectral Doppler = three-fold increase in velocity across region of narrowing; hemodynamic

How do intraparenchymal arteriovenous malformations come about?  What is the usual clinical significance?  In rare cases, how can large AVMs present?

• Come about = vascular trauma to both artery and vein during percutaneous biopsies; asymptomatic

• Clinical signifiance = little significance; resolve sontaneously

• How large in rare cases = 1 - 18%; rare can present with high-output cardiac failure or hemorrhage

What are the color & spectral Doppler findings in AVMS?

• Color Doppler = high-velocity turbulent flow with multiple feeding vessels; color signal outside borders of renal vasculature

• Spectral Doppler = low resistance, high velocity, waveform may be pulsatile/ arterialized

How do pseudoaneurysms come about?  How do they appear on gray-scale sonography?

• Result = vascular trauma, arterial sys. during percutaneous biopsy, or (more frequent) site of vascular anastomosis

• Gray-scale = mimic simple or complex cyst

What is their appearance on color Doppler? Spectral Doppler?

• Color Doppler = Flow easily obtained in lumen, swirling pattern

• Spectral Doppler = central to and from waveform or disorganized arterial tracing

How often are perinephric collections demonstrated in renal tx recipients?  What are the most common collections?

• Demonstrated = up to 50% of renal tx pts

• Most common collection = hematoma, urinoma, lymphocele, and abscess

What is the sonographic appearance of hematomas?  What does their appearance depend on?

• Sono appear.: nonspecific,

• Appearance depend on: presence of air within perirenal collection

 

What are the causes of a urinoma?  What is their sonographic appearance?

• Cause = secondary to either anastomotic leaks or ureteric ischemia; (rare) high-grade collecting system obstruction

• Sono appear.: well-defined, anechoic, may associate w/ hydroephrosis, and increase rapidly in size

How do lymphoceles come about?  How often & when do they occur?  What complication do they most commonly cause?  What other complications can they cause?

• Come about = surgical disruption of iliac lymphatics

• Often & when = often occur 4 - 8 weeks after surgery but may develop after years of txs; most discovered incidentally & asymptomatic

• Complications = lymphoceles most common fluid collection to result in ureteric obstruction; can become infected, obstruct venous drainage

  What are the parenchymal tx pathologies?

• Acute tubular necrosis hyperacute, acute rejection, and infection

What is the major cause of delayed graft function?  Why does it occur?  When is it most common?  The sonographic findings are almost identical to what other abnormality?

• Major cause: acute tubular necrosis result from donor organ ischemia

• Results from donor organ ischemia either or prior to vascular anastomosis or secondary to perioperative hypotension

• Almost identical to acute rejection on gray-scale and Doppler

What are the 3 types of renal tx rejection?  During what periods following surgery do they occur?

• 3 types rejection: chronic rejection, hyperacute rejection, and acute rejeciton

• Periods following each surgeries: acute tubular necrosis = first 2 weeks of tx but may delay by 3 months. Hyperacute rejection = immediately at vascular anastomosis during surgery. Acute rejection = up to 40% of pts in early transplant period, peaking at 1 - 3 weeks after surgery

What are the sonographic findings in acute rejection?

• Acute rejection almost identical to ATN on gray-scale and Doppler

• Gray-scale = increased cortical thickness, increased/ decreased cortical echogenicity, reduction of corticomedullary differentiation, loss of renal sinus echoes, and prominence of pyramids

What are the sonographic findings of chronic rejection?

• Thin renal cortex, prominence central renal sinus fat, reduction of renal size transplant, calcification scattered throughout residual parenchyma

What are the infectious processes that may affect the renal tx?  Which one manifests with air in the collecting system? 

• Infectious process: hematologic seeding or continuous spread from adjacent infected fluid collection

• Air in collecting sys.: air can be observed within collecting echogenic focus w/ distal dirty shadowing

What type of renal tissue is obtained during a renal bx?  What structures should be avoided when guiding for a renal biopsy?

• Type tissue obtained: parenchyma tissue

• Structures to avoid: renal vessels and ureters