Abdomen Ultrasound Chapters 36 Fundamentals of Diagnostic Radiology, 2nd edition Brant and Helms Wil

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Title: Abdomen Ultrasound Chapters 36 Fundamentals of Diagnostic Radiology, 2nd edition Brant and Helms Wil

1
Abdomen UltrasoundChapters 36Fundamentals of
Diagnostic Radiology 2nd editionBrant and
HelmsWilliam E. BrantSupplemental internet
and journal references available upon request for
figures
2
Peritoneal Cavity Fluid

Potential space visualized when fluid present
Fluid pools in dependent recesses
subdiaphragmatic subhepatic pericolic gutters
pelvic cul-de-sac
The most dependent recesses are Morrisons pouch
(hepatorenal recess) and pelvic cul-de-sac
Communicate via pericolic gutters
Transudative fluid is anechoic (ascites urine
bile)
Exudative fluid may contain echogenic particles
layering debris septations (hemorrhage pus
malignant ascites extraluminal bowel content)

3
Peritoneal Cavity Abscess

Abscesses most commonly form in dependent
recesses
Loculated fluid collections
May be anechoic to densely echogenic some appear
solid
Possible features
Fluid levels
Layering debris
Thick walls and septations
Gas (brightly echogenic with reverberation
artifact)
Mass effect and displacement of adjacent
structures

4
Peritoneal Cavity Tumor

Primary peritoneal tumors
Mesothelioma
Desmoid
Carcinoid
Lymphoma
Appear as hypoechoic solid masses
Dense fibrous tissue or calcifications may cause
acoustic shadowing

5
Peritoneal Cavity Metastases

Metastases are the most common peritoneal space
tumors
Implants occur on visceral and parietal
peritoneal layers
Appear as hypoechoic solid masses
Ascites often present /- septations and
echogenic debris
Omental caking
Thickening of greater omentum by tumor deposits
Solid tissue layer separating bowel from
abdominal wall
Most common primary malignancies
Ovarian
Colon
Pancreas
Gastric

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Retroperitoneum Anatomy

Posterior to posterior parietal peritoneum
Compartments and organs discussed earlier
Diaphragmatic crura
Hypoechoic linear bands adjacent to spine
Landmarks for locations of adrenal glands (see
later)
Aorta and IVC
Retroperitoneal fat

8
Retroperitoneum Fluid Collections

Hemorrhage
Echogenic clotted blood may appear as a solid
mass
Infection
Urinoma
Pancreatic fluid collections
Cystic masses
Lymphoceles
Lymphangiomas
Renal cysts
Teratomas
Doppler to reveal enlarged vessels and vascular
collaterals

9
Retroperitoneum Adenopathy

Pathological lymph node enlargement
Short axis diameter gt 1.5 cm
Multiple nodes larger than 1.0 cm
Enlarged lymph nodes homogeneous hypoechoic
round or oval
Some enlarged nodes may appear so hypoechoic they
appear cystic may have increased
through-transmission
Causes of enlarged lymph nodes nodal masses
Lymphoma (most common)
Metastases (testicular renal pelvic GI
melanoma)
Infection (especially in AIDS patients)

10
Retroperitoneum Tumors

Most commonly mesenchymal origin
Liposarcoma
Leiomyosacroma
Malignant fibrous histiocytoma
Aggressive tumors
Most are large heterogeneous partially cystic
Invasion of organs and muscles
Germ cell tumors
Primary or secondary benign or malignant

11
Liver

Normal appearance
Homogeneous echotexture
Echogenicity equal to or slightly higher than
kidney
Smooth surface
Hepatic veins
Thin-walled anechoic tubes
Portal triads
Seen as echogenic spots throughout liver
Comprised of portal vein bile duct hepatic
artery and surrounding fibrofatty tissue

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Liver Fatty Infiltration

Increased echogenicity
Affected areas more echogenic than normal kidney
Diminished beam penetration
More difficult to evaluate deeper structures
Decreased visualization of diaphragm
Coarsened echotexture
Decreased visualization of portal triads
Focal fatty sparing
Darker areas on ultrasound

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Acute Hepatitis

Multiple etiologies
Diffuse hepatic edema
Starry sky appearance
Decreased hepatic echogenicity
Portal triads appear bright against darkened
background of edematous parenchyma
Other causes of starry sky appearance
Diffuse leukemic lymphomatous infiltration
Toxic shock syndrome
Decreased glycogen stores in liver

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Passive Hepatic Congestion

Congestive heart failure
Stasis of blood in liver
Hepatomegaly
Hepatic veins and IVC distension
Pulsatile portal vein flow Doppler
Normally continuous non-phasic portal venous
flow
Becomes pulsatile phasic flow due to transmission
of right atrial activity through congestion
sinusoids
Other findings
Ascites pleural effusion and/or pericardial
effusion

20
Hepatic Cirrhosis

Heterogeneous coarsened hepatic echotexture
Increased echogenicity proportional to extent of
fatty infiltration
Nodular contour of hepatic surface (fine or
coarse)
Multiple ill-defined nodules evident
Alcoholic cirrhosis shrunken right lobe
hypertrophied left and caudate lobes
Advanced cirrhosis (all causes) diffusely
shrunken liver
Loss of normal triphasic hepatic venous flow
(flattened)
Low sensitivity for detection of malignancy
although detection of discrete focal mass in
cirrhotic liver by US is highly predictive of
malignancy

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Portal Hypertension

Portosystemic vascular collaterals
Dilated portal vein (gt 13 mm diameter)
Dilated splenic and superior mesenteric veins (gt
10 mm diameter)
Splenomegaly
Ascites
Reversed portal venous flow (hepatofugal)
diagnostic of portal venous hypertension
Dilated umbilical vein with flow also highly
specific for portal venous hypertension

23
Portal Vein Thrombosis

Enlarged portal vein with thrombus
Decreased or complete loss of flow within portal
vein by Doppler imaging
Variable appearance of thrombus
Anechoic to hyperechoic depending on age
Tumor thrombus invading portal vein
Look for arterial waveforms within the thrombus
to suggest vascularized tumor

24
Liver Masses

Simple cysts
Anechoic fluid
Thin walls
Increased through-transmission
Many septated with lobulated contour
Avascular no flow on Doppler
Abscess
Complex fluid collections
Echogenic fluid
Fluid-fluid layers
Gas
May calcify when healing/healed

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Liver Masses

Microabscesses
Immunocompromised patients
Fungal or parasitic agents
Target appearance common central echogenic
focus with peripheral hypoechoic halo
Cavernous hemangioma
Classic appearance well-defined homogeneous
hyperechoic mass
Large lesions may have hypoechoic thrombus
fibrosis calcifications
About 2 may enlarge over time
Lesions with non-classic appearance should be
followed up or confirmed with other imaging
modalities (CT MR NM Angio)

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Liver Masses

Hepatocellular carcinoma
Solitary multifocal or diffuse
Variable appearances range from
Hyperechoic with internal fat
Hypoechoic and heterogeneous (necrosis)
Hypervascular with prominent vascularity
Tumor invasion of portal and hepatic veins common
Solid lesion in a diseased liver should be
considered suspicious for malignancy

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Liver Masses

Metastases
Hypoechoic to hyperechoic homogeneous to
heterogeneous to calcified
Consider in differential of all solid and
atypical cystic lesions
Other non-specific appearing lesions
Adenoma
Focal nodular hyperplasia
Sarcoma
Cholangiocarcinoma (peripheral)
Metastases

32
Bile Ducts

Run in portal triads with portal venous and
hepatic arterial branches
Normal caliber of intrahepatic ducts
2 mm diameter or less in the central liver
40 of diameter of adjacent portal vein
Transition from intrahepatic to extrahepatic at
junction of right and left lobe ducts to form
common hepatic duct
Common bile duct formed by cystic duct joining
hepatic duct
Common duct is generic term for extrahepatic
duct at porta hepatis

33
Bile Ducts

Common duct courses anterior to
Main portal vein
Right portal vein
Right hepatic artery
Normal caliber of common duct is 4 - 6 mm in
adults (up to age 60) from inner wall to inner
wall
After age 60 add 1 mm for each decade above 60
years age to determine upper limits of normal
duct caliber
Characteristic configuration at hepatoduodenal
ligament is Mickey Mouse configuration
PV is head HA left ear CBD is right ear
Many normal variations in appearance/configuration

34
Biliary Ductal Dilatation

Ductal tortuosity
Greater than 40 of diameter of adjacent portal
vein
Visualize ducts in periphery of liver
Common bile duct exceeds normal caliber
parameters
Should attempt to follow dilated CBD to level of
obstruction

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Biliary Ductal Dilatation

Choledocholithiasis
Stones appear as echogenic foci within duct
Not all stones may shadow
Hepatic artery calcifications may mimic stones
Pneumobilia gas within biliary tree
Most commonly results from surgical procedures
(sphincterotomy choledochoenterostomy)
Gas-producing infections
Fistula between biliary tree and intestinal tract
(gallstone ileus perforated duodenal ulcer)
Trauma
Ducts usually dilated with pneumobilia

37
Biliary Ductal Dilatation

Cholangiocarcinoma
Hilar and extrahepatic lesions may present with
biliary obstruction early when small (lt 3 cm
size)
Klatskin tumor refers to hilar cholangiocarcinoma
(10-20)
Most often isoechoic to liver parenchyma but may
be hypo- or hyperechoic
Variable ultrasound appearance
Focal mass at point of obstruction
Nodular thickening of bile duct wall
Polypoid intraluminal mass
May see abrupt termination of dilated duct
without a discrete mass
May invade and obstruct adjacent portal veins

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Biliary Ductal Dilatation

Oriental (Asiatic) cholangiohepatitis
Also known as recurrent pyogenic cholangitis
Precise etiology not clear multifactorial
Parasitic infestation (Clonorchis Ascaris)
Portal vein bacteremia
Malnutrition
Bile ducts focally dilated and/or stenotic
(strictures)
Multiple stones with and without shadowing
Debris within dilated bile ducts

40
Biliary Ductal Dilatation

AIDS-related cholangitis
Opportunistic infections with CMV or
Cryptosporidium
Dilated intra- and extrahepatic bile ducts
Thickened walls of bile ducts and gallbladder
Edema at the ampulla of Vater may be seen as
focal echogenic nodule characteristic finding
Biliary Ascariasis
Worms may obstruct biliary tree and gallbladder
May be seen on ultrasound as moving tubular
structures with echolucent core
Cholangitis cholecystitis pancreatitis

41
Gallbladder

Located on undersurface of liver
Gallbladder neck positioned along interlobar
fissure
Normal wall 3 mm or less in thickness
Mucosa echogenic
Smooth muscle layer is hypoechoic
Diameter of gallbladder is less than 4 cm in most
normals
May have normal folds particularly around
gallbladder neck and near fundus

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Gallbladder Sludge

Normal bile is anechoic
Sludge
Bile may become echogenic when highly
concentrated
Indicative of prolonged lack of bile turnover in
GB (prolonged fasting obstruction)
Cholesterol crystals and calcium bilirubinate
granules precipitate as sludge
May become viscous and form sludge balls or
tumefactive sludge
Sludge balls move with gallbladder
Do not cause acoustic shadowing
Blood pus parasites may also cause more
echogenic bile

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Gallbladder Wall Thickening

Normal wall 3 mm or less in thickness
Measured between gallbladder lumen and liver
parenchyma
Most common causes are ascites hypoproteinemia
cholecystitis
Other causes may be related to
Gallbladder disease (adenomyomatosis carcinoma
AIDS cholangiopathy cholangitis)
Non-biliary disease (CHF edema hepatitis portal
hypertension cirrhosis)

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Gallstones

Typical US appearance
Echogenic objects
Cast acoustic shadows
Mobile
Variant appearances
Non-mobile stones may be adherent to wall
Lack of acoustic shadowing may be require
adjustment of technique to elicit this finding
Mimics of gallstones
Sludge balls echogenic mobile but no
shadowing
Cholesterol and adenomatous polyps echogenic
but non-mobile and non-shadowing
Polyps most often 5 mm or less in size
Polyps gt 1 cm size may be malignant

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Wall-Echo-Shadow Sign

WES sign (also double arc shadow sign)
Gallbladder completely filled with stone(s)
Look for the following triad appearance from
superficial to deep
Gallbladder wall
Echogenic stone
Clean acoustic shadow caused by stone
May differentiate from bowel
Shadow from stone is a clean dark shadow
Shadow from air is dirty brighter shadow

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Acute Cholecystitis

US findings
Gallstones
Thickened gallbladder wall
Positive Murphy sign (focal GB tenderness
elicited by applying direct transducer pressure
over GB)
Pericholecystic fluid
Dilated gallbladder
Wall hyperemia
A true positive Murphy sign is highly predictive
of acute cholecystitis
A negative Murphy sign is evidence against acute
cholecystitis

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Acute Cholecystitis Variants

Gangrenous cholecystitis
Striated appearance of thickened gallbladder wall
Gallbladder perforation
Pericholecystic fluid collection gt 1 cm
Acalculous cholecystitis
At risk patients have prolonged
illness/hospitalization
Trauma
Burns
Major surgery
Parenteral nutrition
Sepsis

55
Emphysematous Cholecystitis

Due to ischemia
Elderly diabetic patients males more common
Gas develops in gallbladder lumen and wall
related to infection by gas-producing organisms
Perforation common high mortality
US appearance
Key is to look for air
Bright reflections associated with ring-down
artifact
Gas bubbles may produce comet-tail artifacts
May have pneumobilia

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Gallbladder Carcinoma

Gallstones often present so detection by US
often difficult
Chronic cholelithiasis is major risk factor
US appearances
Mass replacing the gallbladder (most common) do
not see normal gallbladder
Appears markedly heterogeneous
Diffuse or focal wall thickening (2nd most
common)
Thickening is to greater degree and with greater
irregularity than with other causes
Intraluminal soft tissue mass (least common)
Any intraluminal mass gt 1 cm suspicious for cancer

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Gallbladder

Porcelain gallbladder
Complication of chronic cholecystitis
Calcification of gallbladder wall
Highly echogenic wall with acoustic shadowing
Predisposing condition to gallbladder cancer
Adenomyomatosis
Benign condition hypertrophy of wall smooth
muscle
Focal or diffuse wall thickening
Fundus nearly always involved
Rokitansky-Aschoff sinuses are pockets of mucosa
within the hypertrophied wall smooth muscle
Precipitated cholesterol crystals within sinuses
are very echogenic and produce comet-tail
artifacts

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Spleen

Imaging
Supine position posterolateral intercostal
approach
When enlarged can be evaluated with anterior
subcostal approach at deep inspiration
Normal appearance
Homogeneous parenchyma
Higher echogenicity than liver
Borders may normally be lobulated but smooth and
sharp
Normal length 12 cm or less thickness 6 cm or
less

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Spleen

Accessory spleen
Round well-defined mass
At or near splenic hilum
Homogeneous and isoechoic to splenic parenchyma
Vasculature associated with splenic artery and
vein
Splenomegaly
Length greater than 12 cm
Thickness greater than 6 cm
Parenchyma remains homogeneous with normal
echogenicity

64
Spleen Cystic Lesions

Post-traumatic cyst
80 of splenic cystic lesions
Well-defined anechoic increased
through-transmission
May have thick wall with ring-like calcifications
True epithelial cyst (epidermoid cyst)
Same appearance as post-traumatic cyst
Calcifications in wall less common
Pancreatic fluid collection
Nearly always subcapsular associated with
pancreatitis
May compress adjacent splenic parenchyma

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Spleen Cystic Lesions

Splenic artery aneurysm
Hypoechoic mass in the region of the splenic
hilum
Atherosclerotic calcifications in aneurysm wall
Doppler reveals arterial blood flow
Rupture results in high mortality
Splenic artery pseudoaneurysm
Usually caused by pancreatitis
Fluid collection with thin non-calcified walls
Doppler reveals arterial flow with communication
with the splenic artery

67
Spleen Cystic Lesions

Abscess
May demonstrate echogenic fluid layering debris
air
Some contain anechoic fluid
Ultrasound may be used to guide percutaneous
drainage and catheter placement
Microabscesses
Most common in immunocompromised patients
Multiple small hypoechoic lesions most 5-10 mm
in size
Common agents TB MAI Candida Pneumocystis

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Spleen Solid Lesions

Lymphoma
Hypoechoic lesions in patients with lymphoma are
likely to be foci of lymphoma
May range from numerous and small to few and
large
Spleen may be normal sized and still be diffusely
infiltrated or may be enlarged without
involvement
Infarction
Hypoechoic or anechoic wedge-shaped lesions
Peripheral lesions extend to splenic capsule
Borders may be sharply defined or irregular
Superimposed hemorrhage may extend subcapsular or
result in hemoperitoneum

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Spleen Solid Lesions

Hemangioma
Variable appearance in spleen
Usually hyperechoic and homogeneous
Calcifications may occur in areas of fibrosis
Metastases
Non-specific appearance
Usually hypoechoic and multiple
Hematoma
Most are well-defined and hypoechoic

73
Pancreas

Anatomy
Body and tail anterior to splenic vein
Neck anterior to confluence of splenic vein and
SMV
Head anterior to IVC and envelops the confluence
Uncinate process between IVC and SMV
Normal appearance
Echogenicity varies with age extent of fat
infiltration
Children/young adults echogenicity equal to
liver
Older adults higher echogenicity with fat
infiltration

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Pancreas

Pancreatic duct
May be seen in normal individuals
Normal duct measures 3 mm or less in diameter
tapers progressively toward tail
Imaging
Distal stomach lies between stomach and liver
Left lobe of liver may be used as acoustic window
Stomach may be distended with water to also serve
as acoustic window for imaging pancreas
Spleen may serve as acoustic window for
pancreatic tail

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Acute Pancreatitis

US appearance may be normal in mild cases
Diffuse enlargement
Decreased echogenicity due to edema
Poorly defined margins
Focal pancreatitis often involves the head
Pancreatic fluid collections
Peripancreatic lesser sac splenic hilum
Doppler evaluation
Pseudoaneurysms
Splenic portal superior mesenteric venous
thrombosis

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Chronic Pancreatitis

Fibrosis glandular atrophy
Decreased size and increased echogenicity
Calcifications may be present may be seen within
duct
Pancreatic duct shows alternating dilatation and
constriction

80
Pancreas Solid Masses

Adenocarcinoma
Hypoechoic mass
Subtle distortion and alteration of echotexture
Characteristic appearance sudden termination of
dilated ducts in a hypoechoic mass
Doppler to evaluate for vascular
encasement/invasion
Chronic pancreatitis
Mass of solid fibrinous tissue may be
indistinguishable from adenocarcinoma
Ductal dilatation may be present

81
Pancreas Solid Masses

Islet cell tumor
Most are hypoechoic relative to pancreatic
parenchyma
Variable appearances related to cystic
degeneration calcifications fibrosis
hemorrhage
Endoscopic and intraoperative US higher detection
rate
Metastases
May mimic pancreatic adenocarcinoma
Lymphoma
Enlarged peripancreatic lymph nodes nodal masses

82
Pancreas Cystic Masses

Pseudocyst
Well-defined anechoic smooth-walled
Loculations internal septations common
Internal debris fluid-fluid levels seen with
hemorrhage and infection
Pancreatic cysts
Multiple seen with von Hippel-Lindau syndrome and
autosomal dominant polycystic disease
Solitary true epithelial-lined cysts are rare in
pancreas

83
Pancreas Cystic Masses

Abscess
May contain layering debris echogenic fluid air
Often ill-defined
Microcystic adenoma
Commonly appears as solid lesion
Few large cysts may be visible
Echogenic central stellate scar with
calcification is characteristic
Mucinous cystic tumor
Cysts 2 cm or larger in size
Internal septations and papillary projections may
be present
Cannot differentiate benign and malignant tumors

84
Adrenal Glands

Normal anatomy
Normal glands may be difficult to visualize in
adults
Right gland
Superior to right kidney posterior to IVC
Between liver and right crus of diaphragm
Left gland
Between upper pole of left kidney and aorta
Hypoechoic to retroperitoneal fat isoechoic to
crura of diaphragm
Hypoechoic cortex surrounds echogenic medulla
Limbs are 4-5 cm in length 5-7 mm in width
Newborn adrenal glands larger involute by 3
weeks life

85
Adrenal Glands

Adrenal hyperplasia
Bilateral diffuse enlargement
Multiple small nodules bilaterally
Differential diagnosis
Infection (TB histo CMV)
Metastases
Lymphoma
AIDS with TB fungal or viral infection

86
Adrenal Solid Lesions

Adrenal adenoma
Solid homogeneous mass
Echogenicity similar to kidney
Larger than 4 cm suspicious for malignancy
Adrenal carcinoma
Indistinguishable from adenoma when small (lt 4
cm)
Larger carcinomas are heterogeneous with areas of
necrosis hemorrhage calcification
Doppler imaging to detect venous invasion

87
Adrenal Solid Lesions

Pheochromocytoma
Most originating from adrenal are large 5-6 cm
Mostly solid with cystic areas of
necrosis/hemorrhage
Adrenal myelolipoma
Echogenic mass may be missed due to adjacent fat
Mixed hyper-/hypo-echoic areas due to fatty and
myeloid elements in the tumor
Differential diagnosis for echogenic lesions in
this area
Renal angiomyolipoma
Teratoma
Lipoma liposarcoma

88
Adrenal Cystic Lesions

Benign cysts
Thin walls and septa (lt 3 mm)
Anechoic fluid increased through-transmission
Calcifications of wall and septa common
Complicated cysts possibility of malignancy
Echogenic internal debris
Thick walls
Solid components
Large size (gt 6 cm)

89
Adrenal Hemorrhage

Neonates usually bilateral related to hypoxic
stress
Adults usually unilateral right-sided (85)
Initial Appearance
Hyperechoic mass-like enlargement of gland
Progression
Hypoechoic appearance
Decreasing size
Resolution
Return to normal appearance
Evolution to pseudocyst wall calcifications at
2-4 weeks
Pseudocyst collapse results in coarsely calcified
glands

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Kidneys

Normal appearance and anatomy
Normal length ranges from 9 - 13 cm
Contour may be smooth or lobulated by renal lobes
Renal cortex
Isoechoic to slightly hypoechoic to liver
Distinctly hypoechoic to spleen
Renal medulla (medullary pyramids)
Hypoechoic to cortex cone-shaped
Corticomedullary differentiation most pronounced
in newborns less distinct with age

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Kidneys

Normal appearance and anatomy
Central sinus
Contains fat blood vessels collecting system
lymphatics
Echogenicity same as perirenal fat
Junctional parenchymal defect
Normal variant resulting from incomplete fusion
of upper and lower poles
Wedge shaped echogenic defect at junction of
upper and middle 1/3 of kidney
Collecting systems
May normally appear mildly dilated in
well-hydrated patients and in patients with
distended bladder

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Kidneys Obstruction

Hydronephrosis
Key finding in obstruction
Fluid distension of collecting system
Pitfalls
Acute obstruction (e.g. stone) may result in
only mild hydronephrosis despite severe
obstruction
Presence of hydronephrosis does not always imply
obstruction
Vesicoureteral reflux
Distended bladder
Pregnancy
Active diuresis
Well-hydration
Relieved obstruction with persistent hydration

95
Kidneys Obstruction

Mimics of hydronephrosis
Peripelvic cyst
Multiple renal cysts in renal sinus
Extrarenal pelvis
Normal variant
Renal pelvis extends outside renal sinus

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Renal calcifications

Renal stones
All renal stones appear as bright echogenic foci
on US
Regardless of composition
Acoustic shadowing often not evident due to
technical limitations
Stones as small as few mm in size may be detected
if shadowing is identified
Nephrocalcinosis (medullary)
Calcification of medullary pyramids
Acoustic shadowing only present with dense Ca
Hypercalciuric states (hyperPTH medullary sponge
kidney distal RTA) and Lasix therapy in newborns

97
Diffuse Renal Parenchymal Disease

Acute renal failure (ARF)
Some causes of bilateral obstruction leading to
ARF
Leaking abdominal aortic aneurysm
Pelvic/retroperitoneal tumor (esp. cervical
cancer)
Retroperitoneal fibrosis
Chronic renal failures (CRF)
Multifactorial multiple etiologies
Non-specific appearance of small echogenic
kidneys
Adults with renal length lt 9 cm unlikely to have
reversible renal disease to warrant biopsy

98
Enlarged Kidneys

Length gt 12 - 13 cm
Infiltrative process
Lymphoma
Leukemia
Acute glomerulonephritis
Renal vein thrombosis edema
AIDS nephropathy
Polycystic kidney disease

99
Reflux Nephropathy

Focal findings
Renal parenchymal thinning (focal volume loss)
Underlying scar extends from renal sinus to the
surface
Underlying calyx dilated
Remainder of the kidney is generally normal

100
Renal Masses

Simple cyst
Anechoic fluid
Well-defined far back wall
Increased through-transmission
Imperceptibly thin walls
May have thin septations or thin peripheral
curvilinear calcifications
Peripelvic cyst
Form in renal sinus often multilobed
May mimic hydronephrosis
Do not communicate with renal pelvis

101
Renal Masses

Complicated cyst
Internal debris
Echogenic clot
Fluid-debris level
Thick septations and/or thick walls
Thick or coarse calcifications
Differential diagnosis
Hemorrhage or infection of simple cyst
Cystic tumor
Abscess
Lymphoma
Obstructed upper pole moiety in duplicated system
Calyceal diverticulum
Aneurysm pseudoaneurysm

102
Renal Call Carcinoma

Most common solid renal mass in adults
50 hyperechoic
Highly echogenic RCC may appear like AML but RCC
tends to be more heterogeneous and lacks acoustic
shadowing in absence of calcifications
30 isoechoic
Distort renal contour
10 hypoechoic
5-10 cystic
Cystic internal hemorrhage
20-30 coarse punctate central calcifications

103
Renal Cell Carcinoma

Doppler evaluation
Internal vascularity is strong evidence of RCC
Also evaluate for renal vein IVC invasion by
tumor
Enlarged vein venous collaterals
Echogenic mass in vein
Arterial doppler signal within the tumor thrombus

104
Angiomyolipoma

Classic appearance
Uniformly hyperechoic renal mass with sharp
borders
Seen in 80 of cases
Echogenicity should be at least equal to renal
sinus fat
May show weak acoustic shadowing
Hypervascular
Rarely has cystic components or calcifications

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Transitional Cell Carcinoma

Commonly overlooked by ultrasound due to often
subtle and variable appearances of tumors
Small
Infiltrative
Stenosing
May cause focal hydronephrosis
May appear as soft tissue nodule in a dilated
renal pelvis

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Lymphoma

Common appearance is multiple hypoechoic masses
Appear homogeneous
Low level internal echoes
May appear so hypoechoic to anechoic as to
resemble a cyst
Other patterns
Single dominant mass
Multiple masses
Diffuse infiltration causing renal enlargement
Invasion of central sinus by retroperitoneal
adenopathy

110
Acute Pyelonephritis

Frequently no ultrasound findings
Purpose of imaging patients with UTI is to detect
hydronephrosis obstructing lesion abscess
(renal or perirenal) or other complication
Severe cases may alter renal parenchymal
echotexture contour and homogeneity
Edema
Inflammation
Hemorrhage
Focal involvement has been given several terms
(lobar nephronia focal nephritis) but truly
represent severe focal involvement by
pyelonephritis