Transcript The SPLEEN DMSM 106 HHHoldorf

Ultrasound Technique
Normal Anatomy and Normal Ultrasound appearance
Splenomegaly
Accessory Spleen
Wandering Spleen
Splenic calcifications
Splenic Granulomas
Pathology
Splenic cysts
Splenic Abscess
Splenic Infarcts
Trauma-Perisplenic or Intraperitoneal hematoma
Trauma-Intraparenchymal or subcapsular hematoma
Splenic artery aneurysm
Polysplenia
FAST
Homework
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The normal spleen is difficult to image, as it is
almost totally surrounded by ribs and gascontaining organs.
The recommended technique is to place the
patient in a right lateral Decubitus position
and scan with a 3.5 to 5 MHz, medium focus
transducer through the lower inter-costal
spacers.
Coronal long axis and transverse are routine
views.
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The spleen is an important organ located in
the left upper quadrant (LUQ). It is located
posterior to the stomach and superior and
lateral to the left kidney. In its normal
position, it is usually not clinically palpable.
Vessels, lymphatics and nerves enter and
leave the splenic hilum, which is located
medially. The tail of the pancreas also sits in
the region of the splenic hilum just anterior to
the kidney.
The spleen is seen as a structure with uniform
echo texture and moderate echogenicity and
no visible parenchymal vessels.
 Splenic vessels may be seen in the splenic
hilum.
 The spleen is considered to be slightly more
echogenic than the liver.
 The normal spleen measures less than 12 cm
in length in the carnio-caudal (long axis)
dimension.
 The appearance of the spleen has been
known to be called Crescent.
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The spleen is a peritoneal organ located in
the left upper quadrant between the stomach
and the diaphragm. It is the largest lymphoid
organ
that
filters
damaged
cells,
microorganisms and particulate mater. It also
delivers antigens to the immune system.
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The parenchymal echogenicity of the spleen
varies. The average adult spleen measures:
 12 cm – longitudinal
 8 cm – transverse
 4 cm – thickness
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The normal liver usually does not touch the
spleen. If the left lobe is enlarged, it may
extend into the left upper quadrant anterior
to the spleen. The left lobe of the liver is also
seen anterior to the spleen during the third
trimester of pregnancy.
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The stomach, left kidney, pancreas and
splenic flexure of the colon is located on the
visceral surface of the spleen.
The fundus of the stomach and lesser sac are
medial and anterior to the splenic hilum. The
tail of the pancrease is located posterior to
the stomach and lesser sac as it approaches
the splenic hilum.
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The lesser sac or omental bursa is a cavity
found within the abdomen and is part of the
peritoneal cavity.
It is an irregular part of the peritoneal cavity
that lies mostly posterior to the stomach.
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The left kidney lies anterior and medial to the
spleen. The pancreatic tail is located anterior
to the upper pole of the left kidney in the
splenic hilum.
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Splenomegaly is indicated with a longitudinal
measurement > 12 cm or if the spleen is
inferior to the lower pole of the left kidney.
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Portal hypertension, due to cirrhosis, is the most
common cause of congestive splenomegaly in
adults. Other reasons include:
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Viral infections
Bacterial infections
Rheumatoid arthritis
Hemolytic anemia (Anemia due to the abnormal
breakdown of red blood cells)
Leukemia
Lymphoma
Congestive heart failure
Sickle cell anemia
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Polycythemia Vera- blood disorder resulting
in uncontrolled RBC production causing
hyperviscosity
and
hypercoagulation.
Polycythemia vera may be the cause of
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Splenomegaly
Budd-Chiari Syndrome
Portal vein Thrombosis
Splenic Infarcts
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Diffuse splenomegaly is the most common
feature and manifestation of splenic
disease.
The spleen may be enlarged in a variety of
conditions including liver disease, blood
disorders, infections, and neoplastic
involvement.
With diffuse disease, the spleen may be
less echogenic, more echoic, or have the
same echogenicity as normal.
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Portal hypertension secondary to alcoholic
cirrhosis is the most common cause of
splenomegaly in adults.
In certain conditions, such as malignant
lymphoma and polycythemia vera (a blood
disorder in which the bone marrow makes
too many red blood cells), the spleen may be
massively enlarged and even extend into the
pelvis.
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Developed in embryology, an accessory
spleen is a small nodule of splenic tissue
found apart form the main body of the
spleen.
Found in approximately 10% of the
population, it is most commonly found in the
splenic hilum and adjacent to the tail of the
pancreas.
May be mistaken for Splenomegaly or a focal
mass.
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An accessory spleen is a normal variant that is
commonly found. It may be confused with
enlarged lymph nodes around the spleen, or a
mass in the tail of the pancreas.
The majority of accessory spleens are easy to
recognize sonographically as small rounded
masses, less than 5 cm in diameter. They are
located near the splenic hilum and have
identical echogenicity to the adjacent spleen.
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A condition in which the ligaments that hold
the spleen in place weaken, causing the
spleen to be misplaced, sometimes even into
the pelvis.
Symptoms include an enlargement in the size
of the spleen.
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Granulomas are focal lesions resulting from
previous infections. They are seen as focal bright
echogenic lesions, with or without shadowing.
Histoplasmosis (an infection caused by breathing in spores of
fungus often found in bird and bat droppings) and tuberculosis
are the most common causes of granulomas.
Granulomas are also found in the liver and lungs.
Other splenic calcifications can be associated
with
 Splenic artery or splenic artery aneurysms
 Splenic infarct (as they evolve)
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Sonography is useful to evaluate both
focal and diffuse diseases of the spleen.
Nuclear Medicine imaging may be useful in
specific situations and ultrasound is often
requested to characterize a focal defect
seen on the radio-isotope liver-spleen
scan.
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ABSCESSSplenic abscesses are most
commonly caused by spread of adjacent
infections (subphrenic, pancreatic, or perinephric
abscesses). Immunocompromised patients are
susceptible
to
splenic
abscesses.
Sonographically, the abscess is often a mixed
lesion similar to a hematoma. Others may be
anechoic or have low levels of internal echoes.
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Splenic infection is associated with general
abdominal sepsis.
Damaged splenic tissue is a good culture
medium, susceptible to infection, with
filtered bacteria available in the spleen.
Sonographically, splenic abscesses are seen
as complex cystic lesions. The presence of gas
may produce echogenic foci with an
associated reverberation (comet-tail) artifact.
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Infarcts: IV narcotic drug abuse leading to
bacterial endodcarditis is a major cause of
splenic infarction and its complication:
Splenic abscess.
Embolic fragments from infected heart
valves are carried in the bloodstream and
lodge in the spleen causing an infarct
which may heal or progress to an abscess.
Infarcts may also be caused by leukemia
and pancreatic cancer.
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Splenic infarcts are common in patients with
bacterial endocarditis and splenic artery
aneurysms.
They present as a peripheral wedge-shaped
hypoechoic lesion.
The sonographic appearance of an infarct will
change over time, as do hematomas. The initial
ischemia and edema will appear as a hypoechoic
wedge of tissue. With necrosis and liquification,
the area will appear anechoic and ultimately will
calcify.
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Sonographically, fresh infarcts are well
defined, hypoechoic wedge-shaped focal
lesions. The base of the wedge is towards
the capsule and the apex towards the
hilum. With time, the lesion shrinks and
becomes more echogenic.
Complete healing may occur.
Splenic trauma may result in a parenchymal or
subcapsular hematoma or splenic laceration with
associated hemoperitoneum.
 Clinical symptoms depend on the extent of blood
loss.
 If the splenic capsule is intact, a subcapsular
hematoma may be seen as a peripheral crescentshaped collection.
 If the spleen is lacerated, a hemoperitoneum will
occur which may be located in the LUQ or extend
into the other peritoneal compartments, including
the paracolic gutters, pelvis, and right side.
Conservative management is preferred to
spenectomy if the patient is clinically stable.
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Perisplenic or intraperitoneal hematomas
results with capsule RUPTURE. After capsule
rupture, fluid is typically demonstrated to be
loculated around the spleen, although blood
may spread within the peritoneal cavity.
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Intraparenchymal or subcapsular hematomas
result when the splenic capsule remains
intact (DOES NOT RUPTURE).
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Typically, when a calcified circle is seen in the
left upper quadrant on an x-ray, a splenic artery
aneurysm is suspected.
Sonographically, a splenic artery aneurysm may
appear as a cystic mass, or if calcified, a
hyperechoic shadowing foci in the area of the
splenic artery. The artery should be traced from
the celiac axis along the anterior aspect of the
pancreatic tail to the splenic hilum. Filling the
stomach with water may aid in visualizing the
pancreatic tail.
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Heterotaxia: or situs ambiguous, is the
disruption in the development of the normal
asymmetric arrangement of abdominal
organs and vessels.
Heterotaxia is a generic term defining the
mis-arrangement of abdominal structures.
Polysplenia
and
asplenia
are
two
classifications of heterotaxia.
Sonographers encounter heterotaxia in the
neonate patient.
 The initial presentation is with symptoms of
congenital heart disease or jaundice due to
biliary tract abnormalities.
 Polysplenia: defined as bilateral left-sidedness, is
associated with the following abnormalities:
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Multiple LUQ spleens
Biliary atresia / absent gallbladder
Intestinal malrotation
Azygous continuation of interrupted IVC
Cardiac defects
Azygous continuation of interrupted IVC
 Rare
 Frequently associated with other congenital
anomalies
 Occurs in 0.6% of patients with congenital heart
defects
 In usual form, the IVC is interrupted above level
of renal veins
 There is absence of the hepatic segment of the
IVC and the post-renal IVC continues as azygos
and hemiazygos veins
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Asplenia, defined as bilateral right-sidedness,
is
associated
with
the
following
abnormalities:
 Absent spleen
 Midline liver and gallbladder
 Intestinal malroatation
 Reversed positions of aorta and IVC
 Cardiac defects
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Focused Assessment with Sonography for
Trauma (FAST) is utilized in the emergency
department to document the presence of
free fluid in the peritoneal cavity.
The FAST exam also allows analysis for
possible hemopericardium, hemothorax,
solid organ damage, and retroperitoneal
injury.
 2007 AIUM
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The ultrasound appearance of intraperitoneal
blood depends on the age, amount an physical
state of the clot.
The timing of blood coagulation is not fully
understood and acute bleeds may have various
sonographic appearances.
Most medical professionals assume that
hemoperitoneum
will
appear
anechoic,
although, one may see an irregular marginated,
echogenic mass that may mimic that of an
enlarged spleen.
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In a patient with a history of splenic rupture
or surgery, splenic cells may implant
throughout the peritoneal cavity
(autotransplanatation) resulting in a ectopic
spleen.
This occurrence is called POSTTRAUMATIC
SPENOSIS. Spenosis is often asymptomatic
and may mimic other pathologies.
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1. Submit an image of a normal spleen in
Longitudinal and Transverse views.
2. Submit an image of a splenic abscess.
3. Submit an image of a splenic infarct.
4. Submit an image of a splenic laceration
with associated hemoperitoneum.
5.Submit an image of a wandering spleen.
6. Submit an image of an accessory spleen.
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A. breakdown of hemoglobin
B. Formation of bile pigments
C. Formation of antibodies
D. A reservoir for blood
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1. Cystic degeneration of infarcts of
hematomas.
2. Cysts associated with adult polycystic
kidney disease.
3. Parasitic cysts of the spleen
(echinococcal cysts)
4. Epidermoid cysts of the spleen.
5. Pancreatic pseudocysts
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The typical appearance of a splenic infarct
is a peripheral wedge-shaped hypoechoic
lesion
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An intra-parenchymical or sub-capsular
hematoma occurs with splenic trauma in
which the splenic capsule remains intact.
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A
peri-splenic
or
intra-peritoneal
hematoma occurs with splenic trauma in
which the splenic capsule ruptures.