• common in half of adults over 50
• chances increase with age
• asymptomatic
• usually found in renal cortex but can occur anywhere in the kidney
• May hemorrage causing internal echoes
• significant: distorts the calyces, obstructs the kidney

round

oval

anechoic

thin well defined walls

enhancment

absence of color flow

Parapelvic cyst

aka

Renal Sinus Cysts

• asymptomatic
• may cause obstruction, infection, hypertension depending on the size and location
• found in the renal hilum or sinus
• can be confused with hydronephrosis
• DOES NOT communicate with the collecting system

Polycystic renal disease

Adult polycystic kidney disease (APKD)

Autosomal dominant polycystic kidney disease (ADPKD)

• decreased renal function sometimes leads to renal failure: hypertension, uremia, abdominal/flank pain, fever, chill with infection
• Hematuria
• Bilateral enlarged kidneys

• Bilateral enlarged enlarged kidneys
• Multiple cysts of variable size(usually large)
• kidneys lose their shape

Polycystic renal disease

What do patients with APKD look like?

• will have cysts in other organs
• check liver (most common), spleen, pancreas
• symptoms are usually delayed.......slow growing
• causes renal failure by age 50

Infantile polycystic kidney disease

(IPKD)

autosomal recessive polycystic kidney disease

• Both parents have to have gene to pass to child
• may be seen during fetal

• bilateral enalrged echogenic kidneys
• multiple cysts are too small to be seen
• cysts interfaces cause increase in echogenicity
• decrease renal function

• rapid progression: kidney failure/death
• uremia

• loss of definition between the cortex/ medulla/ sinus junction
• increased meduallary echogenicity
• small (microscopic) cysts in the pyramids (interfaces) cause increase in echogenicity of the pyramids

• rare
• not hereditary
• benign
• found in children
• renal function usually normal

• echogenic pyramids

multicystic dysplastic kidney

MDKD

1. most common palpable mass in neonates
2. restrict growth
3. polyuria
4. hypertension
5. unilateral, bhilateral is incompatible with life
6. kidney is nonfunctional
7. not herditary

• multiple cysts varying in size (usually large)
• difficult to identify the renal sinus
• children(early stages): large kidney/large cyst
• Adult(end stage): small kidney

• autosomal dominant
• may cause cysts
• lipomas (fatty tumors)
• fleshy nodules
• "tissue growth"
• fatty nodules

Renal neoplasms

neoplasms=new growth

• malignant and benign tumors (cannot be differentiated from eachother sonografically)
• biopsy
• CT is the modality of choice fror tumor staging

• most common cortical renal mass
• benign
• asymptomatic

• benign tumor
• hemorrage

• well defined
• spokewheel pattern with a central scar
• hemorrage

Angiomyolipoma

AML

hamartoma

• female
• uncommon benign tumor composed mostly of fat cells(muscle and blood vessels
• usually found in renal cortex
• associated with tuberous sclerosis
• causes hematuria if ruptures
• renal funtion is normal

• appears as a focal echogenic homogeneous mass
• echogenicity exceeds that of the renal sinus
• may have enhancement

angio=blood vessel

myo=muscle

lipoma=fat

Renal cell carcinoma

(adenocarcinoma)

(hypernephroma)

(RCC)

• hematuria
• weight loss, fatigue, flankpain, palpable mass, fever with infection
• most common renal cancer
• may affect opposit kidney or IVC
• HYPERVASCULAR tumor

• varied usually solid mass: hyperechoic, complex, cystic, may have calcifications
• may extend into the liver, nodes, adrenals
• may displace the renal pyramids, invade renal architecture

What are the stages of RCC?

1. Confined to the kidney
2. Spread to perinephric fat but contained within the Gerotas fascia
3. Spread to renal vein and IVC
4. invades neighboring structures

Transitional cell carcinoma

TCC

• most common tumor of the collecting system (starts)
• Hematuria, weight loss, fatigue, fever, flank pain
• causes hydronophrosis
• can start in the urinay tract/bladder (bladder mass)

Wilms Tumor

NEPHROBLASTOMA

• palpable mass in children
• abdominal pain, N&V, anorexia, Hematuria
• usually unilateral
• look for extension into renal vein and IVC
• most common renal mass in children
• may necrose and become cystic
• usually noticed by 3-5 years of age
• malignant

• look for extension into renal vein and IVC
• homogeneous/echogenic
• may necrose and become cystic
• LARGE/PALPABLE MASS

• compostion can be calcium, uric acid or cystine
• causes pain/Hydonephrosis if obstructs
• N&V
• absence of ureter jets is a sign of obstruction
• ureteral stone dilates proximal

• echogenic foci with shadowing
• absence of ureter jets is a sign of obstruction

• large/fills the entire collecting system
• shadows
• know all causes of hydronephrosis:instrinsic, aquired
• anuria or oliguria is a sign of obstruction

1. instrinsic
2. acquired

• decreased output
• hydronephrosis
• enlarged hypochoic kidneys
• associated with RAS

• loss of perfusion (blood flow)
• caused by disease, infection, obstruction
• increased incidence with diabetes
• hypertension

• increased BUN and creatinine
• decreased serum calcium, urine specific gravity
• proteinuria
• RBC/WBC in urine
• anemia

• decrease in kidney size<8cm
• increased echogenicity due to fibrosis and scarring
• small echogenic kidney "atrophy"

Glomerulonephritis

(acute)

• increased cortical echoes
• echogenicity exceeds that of the liver

Acute Pyelonephritis

APN

• Kidneys can be normal or increased in size
• related to ascending UTI

Acute Tubular Necrosis

ATN

• most common renal disease to cause renal failure
• increased renal size with hyerechoic pyramids

• pus
• sometimes obstructs ureters
• low level echoes in a dilated collecting system

• fever, leukocytosis, flank pain
• varied US appearance
• may have shaddows from gas

• Normal renal arterial flow demonstrates flow in systole and diastole that is characteristic of a LOW impendence bed
• Doppler peak systole velocities are generally equal to or less than 100cm/sec

Renal Artery stenosis

RAS

• exam is tedious study with a high technical failure rate
• Doppler of the renal arteries is difficult due to body habitus, motion, tortuous vessels
• Primarly caused by atherosclerosis/arteriosclerosis
• It causes renal hypertension, infarction, small kidney, renal insufficiency

• RAR=renal artery ratio
• sample doppler tracing are taken from the renal arteries and aorta

• renal artery peak systolic velcoity divided by aortic peak systolic velocity
• RAR>3.5 is suspicious for RAS
• peak main renal artery systolic velocity>180cm/sec with post stenotic turbulence is also suspicious for RAS
• SPECTRAL BROADENING and TARDUS PARVUS waveform is a sign of RAS
• RENAL ARFTERIOGRAPHY is aninvasive exam but is commonly used to r/o RAS

• Restsitance is an indicator of stenosis
• RI of 0.7 is the upper limits of normal
• as resistance increases the RI will increase

• enlargment of the kidneyin the acute stages
• vein will be dilated with the absence of doppler flow
• Clot may be visible as echogenic material in the vein lumen
• evaluate the IVC for extension

• the most common place of the transplanted kidney is the RLQ
• Right iliac region

• lympoceles occur as early as 1 week post op
• usually found medially or inferior to the lower pole of the kidney
• LARGE, anechoic, may have septaions and debri
• urinomas occur within 1-2 weeks post op
• hypoechoic
• hematomas most complex appearing

• herniation of bladder wall (outpouchings)
• may be congenital or acquired

Bladder Inflammation

(cystitis)

• appear normal on ultrasound
• repeated infections will cause the bladder wall to become thickened due to scarring and fibrosis
• wall thickness between 3-6mm

• major complicatoin of renal transplant is graft rejection

• overall increase in size decreases echogencity
• baseline sonograms are done to document size of kidney after transplant

• enlargement of pyramids
• (swelling) hypoechoic cortex and cortical thickening
• distortion of renal outline
• patchy sonolucent areas

ATN

(acute tubular necrosis)

• the most common cause of post op renal transplant failure (50%)
• occurs after loss of blood supply to the kidney
• associated with prolonged ischemia
• creatinine is elevated
• USF no early change in kidney
• difficult to distinguish from rejection
• hypotension

• early signs of obstruction are anuria or severe oliguria
• USF hydronephrosis

• URINOMA
• ABSCESS
• HEMATOMA
• LYMPHOCELE

• occurs when an organ or part of an organ undergoes necrosis due to lack of blood flow
• seen in the first 24 hours the infarcted part may appear hypoechoic

• infarcted area will become smaller and more echogenic secondary to scarring
• complete arterial occlusion or multiple infarcts will result in a small hyperechoic kidney

• 95% are transitional cell carcinoma
• (TCC) usually not detected until advanced
• can cause hydronephrosis if obstructed

• can be seen as low level echoes in bladder
• decub patient to see if mobile

• cystic like enlargement of the lover end of the ureters
• congenital or inquired
• usually small and asymptomatic
• large ones cause obstruction (bladder outlet obstruction)
• infection

• the most common site of obstruction by calculi is at the UPJ
• uretovesical (narrowest part)
• CHECK URETER JETS

Candle sign

• urachus is fibrous tissue extending from the naval to the bladder
• it is a remnant of part of the duct of the allantois of the embryo
• congenital
• fluid is trapped ina section of the urachus

• indwelling (stays in all the time)

1. Calculi
2. Neoplasms
3. Catheter
4. Tumor
5. Inflammation
6. Stricture
7. Pregnancy

1. Rejection
2. Decreased renal function
3. ATN
4. Obstructive nephropathy
5. extraperitoneal fluid collections
6. cyclosporine toxicity
7. infarction