Splenic Infarction

Published on 20/07/2015 by admin

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Last modified 20/07/2015

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 Diagnosis best made on portal venous phase images due to heterogeneous arterial phase enhancement

image Global infarction: Complete nonenhancement of spleen

– ± cortical rim sign: Preserved enhancement of peripheral rim of spleen in massive infarction
image Segmental infarction: Wedge-shaped or rounded low-attenuation area usually at periphery of spleen

– Can be multiple, especially when caused by emboli
• Chronic findings on CECT

image Most often results in scarring and volume loss
image Multiple repetitive infarcts in sickle cell disease can lead to small, calcified spleen (autoinfarcted spleen)
image Infarct can develop into splenic cyst
• MR findings: Low signal on T1WI, heterogeneous high signal on T2WI, and hypoenhancing on T1WI C+ images
• Complications (< 20% of patients)

image Perisplenic fluid/hematoma suggests splenic rupture
image Development of rim-enhancing fluid collection: Splenic abscess

TOP DIFFERENTIAL DIAGNOSES

• Splenic laceration
• Splenic cyst or abscess
• Heterogeneous arterial phase enhancement of spleen
• Splenic tumors

CLINICAL ISSUES

• Many different causes, but 2 most common are 

image Hematologic disease or hematologic malignancies (sickle cell, myelofibrosis, leukemia, etc.)
image Embolic conditions (septic emboli, cardiac emboli from atrial fibrillation, etc.)
• Most cases require no treatment, but rarely surgery or intervention for pain or complications
image
(Left) Axial CECT in a sickle cell patient demonstrates an enlarged spleen with multiple wedge-shaped acute splenic infarcts image. While sickle cell patients can develop a small, calcified autoinfarcted spleen, the spleen may be enlarged in the early stages of the disease.

image
(Right) Axial CECT demonstrates a large, global infarct of the spleen with only a tiny amount of enhancing splenic tissue image. Notice the peripheral enhancement (rim sign) image at the margins of the infarct as a result of preserved flow through capsular vessels.
image
(Left) Axial CECT in a 67-year-old man with a 10-year history of atrial fibrillation, now presenting with acute LUQ pain, demonstrates a peripheral, low-attenuation splenic infarct with straight margins image.

image
(Right) Axial CECT in the same patient identifies a left ventricular thrombus image as the source of the arterial embolus to the spleen. Embolic disease is likely the most common cause of splenic infarcts in older patients.

TERMINOLOGY

Definitions

• Global or segmental parenchymal splenic ischemia and necrosis caused by vascular occlusion

IMAGING

General Features

• Best diagnostic clue

image Peripheral, wedge-shaped, nonenhancing areas within splenic parenchyma on CECT in patients with LUQ pain
• Location

image Entire spleen may be infarcted or more commonly segmental areas
• Size

image Variable: Global or segmental
image Spleen may or may not demonstrate splenomegaly
• Morphology

image Most commonly wedge-shaped areas of nonenhancement when infarct is segmental

– Straight margins indicate vascular etiology (rather than a mass or fluid collection)
– May very rarely be rounded (atypical appearance)

Radiographic Findings

• Radiography

image May be associated with lower left lobe atelectasis and pleural effusion on chest x-ray

CT Findings

• NECT

image Infarcts may be difficult (or impossible) to visualize without intravenous contrast
image Areas of hemorrhagic transformation within infarcts appear hyperdense on NECT
• CECT

image Acute findings

– Diagnosis best made on portal venous phase images: Heterogeneous enhancement during arterial phase (due to differential enhancement of red and white pulp) makes identification of subtle infarcts difficult
– Global: Complete nonenhancement of spleen

image ± cortical rim sign: Preserved enhancement of peripheral rim of spleen in massive infarction due to preserved flow from capsular vessels
image Mottled higher density areas within infarcted spleen may represent either tiny islands of residual enhancing splenic tissue or hemorrhage
– Segmental: Wedge-shaped or rounded low-attenuation area usually at periphery of spleen

image Can be multiple, especially when caused by emboli
image In some instances, accessory spleens (splenules) may be infarcted
image Spleen may or may not be enlarged in acute phase
– Complications (< 20% of patients)

image Presence of fluid or hematoma surrounding spleen in setting of infarct suggests splenic rupture (most often in setting of large or global infarct)
image Development of discrete rim-enhancing fluid collection ± internal gas should raise concern for splenic abscess
image Chronic findings

– Infarcts should evolve over time, leaving areas of scarring and volume loss in spleen

image Sites of old infarcts may show calcification
image Remaining spleen may undergo compensatory hypertrophy
– Multiple repetitive infarcts in sickle cell disease can lead to a small, calcified spleen (autoinfarcted spleen)
– Infarct can develop into splenic cyst (secondary or acquired cyst)

MR Findings

• T1WI

image Low signal within area of infarct (can show high T1WI signal due to hemorrhagic infarct)
• T2WI

image Heterogeneous high signal within area of infarct
• T1WI C+

image Wedge-shaped area of hypoenhancement

Ultrasonographic Findings

• Grayscale ultrasound

image Wedge-shaped hypoechoic area(s) within periphery of spleen

– May rarely be rounded or irregularly shaped at center of spleen (atypical)
image Bright band sign: Highly echogenic linear bands in area of infarct may be specific sign of infarction
• Color Doppler

image Diminished or absent flow in areas of infarction

Angiographic Findings

• 

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