1. Ultrasound of the Spleen
Wendy Blount, DVM
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2. Indications for Spleen Ultrasound
Palpable mass in the abdomen or pendulous abdomen
Fluid in the abdomen
Abdominal trauma (AFASTSM)
Abdominal pain
Enlarged spleen or mid-abdominal mass seen on radiograph
Staging of neoplasia (usually with FNA)
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3. Indications for Spleen Ultrasound
Evaluation of anemias, thrombocytopenias and lymphadenopathies
Hemorrhagic pericardial effusion
Ventricular arrhythmia
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4. Patient Preparation Place in dorsal or right lateral recumbency
Right lateral recumbency for:
Compromised & deep chested patients
Head of the spleen on deep chested dogs (intercostal)
Landmarks for finding the spleen:
Head is caudal to the stomach
Spleen often mostly in the left abdomen
Tail can range from right to caudal relative to the head
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5. Transition Adjustments
Depth - Adjust according to size of spleen
More shallow for cats, deeper for giant spleens & the canine head of the spleen
Frequency - usually MHz (higher)
Gain and Contrast – usually no change from liver
TGC - Bottom levers may need to go to the middle for head of spleen (they were right for liver)
Top levers may need to go right for body/tail of spleen
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6. Image Views Sagittal & transverse Views (4 each = 8)
1. & Head (cranial) – under the rib cage
2. & Cranial Body
3. & Hilus – splenic vein
4. & Tail (caudal or right)
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7. Image Views Sagittal & transverse Views (4 each = 8)
1. & Head (cranial) – under the rib cage
2. & Cranial Body
3. & Hilus – splenic vein
4. & Tail (caudal or right)
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8. Image Views Sagittal & transverse Views (4 each = 8)
1. & Head (cranial) – under the rib cage
2. & Cranial Body
3. & Hilus – splenic vein
4. & Tail (caudal or right)
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9. Mark Jackson – Merdidian TX
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10. Telemedicine Videos Saggital – head and cranial body of spleen
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11. Telemedicine Videos Saggital – head and cranial body of spleen
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12. Telemedicine Videos Saggital – head and cranial body of spleen
Saggital – hilus and tail of spleen
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13. Telemedicine Videos Saggital – head and cranial body of spleen
Saggital – hilus and tail of spleen
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14. Telemedicine Videos Saggital – head and cranial body of spleen
Saggital – hilus and tail of spleen
Include hilus in both
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15. Video Academy of Veterinary Imaging: dorsal recumbency
Oncura: lateral recumbency (no video)
Ultrasound of the Spleen
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16. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
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17. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
spleen
stomach
stomach
liver
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18. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
spleen
stomach
stomach
liver
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19. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
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20. Goals – Spleen Ultrasound
Normal echotexture spleen
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
Assess whether echotexture is normal or mottled
Spleen has finer echotexture than liver & falciform fat
Mottled spleen - neoplasia
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21. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
Assess whether echotexture is normal or mottled
Spleen has finer echotexture than liver & falciform fat
Mottled spleen with irregular margins - neoplasia
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22. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
Assess whether echotexture is normal or mottled
Spleen has finer echotexture than liver & falciform fat
Mottled spleen –lymphoid hyperplasia
Mottled spleen - neoplasia
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23. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
Assess whether echotexture is normal or mottled
Spleen has finer echotexture than liver & falciform fat
Search for hypoechoic or hyperechoic nodules (+FNA)
Assess size of spleen if markedly enlarged
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24. Goals – Spleen Ultrasound
hemangiosarcoma
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
Assess whether echotexture is normal or mottled
Spleen has finer echotexture than liver & falciform fat
Search for hypoechoic or hyperechoic nodules (FNA)
Assess size of spleen
myelolipoma
infarct
lymphoma
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25. Goals – Spleen Ultrasound
Assess echogenicity relative to fat, liver, kidney
Fat is SLiCK – white  black
Fat  Spleen  Liver  Cortex of Kidney
Compared to the kidney cortex at the cranial body
Compared to the liver at the head (Liver-Stomach-Spleen)
Assess whether echotexture is normal or mottled
Spleen has finer echotexture than liver & falciform fat
Search for hypoechoic or hyperechoic nodules (FNA)
Assess size of spleen if markedly enlarged
Spleen – target lesions
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26. Goals – Spleen Ultrasound
Evaluate splenic margins for normal shape
Normal tail is bluntly pointed, margins smooth
Look for passive congestion (enlarged splenic veins)
Look for infarction, thrombosis, torsion
Torsion – hypoechoic spleen with pronounced hyperechoic trabeculae
Starry Sky Effect
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27. Goals – Spleen Ultrasound
Evaluate splenic margins for normal shape
Normal tail is bluntly pointed, margins smooth
Look for passive congestion (enlarged splenic veins)
Look for infarction, thrombosis, torsion
Splenic torsion – Starry Sky
No Doppler activity
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28. Goals – Spleen Ultrasound
Evaluate splenic margins for normal shape
Normal tail is bluntly pointed, margins smooth
Look for passive congestion (enlarged splenic veins)
Look for infarction, thrombosis, torsion
Splenic infarct – Starry Sky with hyperechoic wedge
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29. Tips – Spleen Ultrasound
The size of the canine spleen varies a great deal
Sedation can make it very large
The normal feline spleen is much smaller than canine
Use a light touch or standoff pad for the feline spleen
Look more cranial and lateral in the cat than in the dog
May be under the last rib in the cat
Folded spleen or thickness >10mm indicates splenomegaly in the cat
In cats, splenomegaly is almost always pathologic
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30. Tips – Spleen Ultrasound
The size of the canine spleen varies a great deal
Sedation can make it very large
The normal feline spleen is much smaller than canine
Use a light touch or standoff pad for the feline spleen
Look more cranial and lateral in the cat than in the dog
May be under the last rib in the cat
Folded spleen of thickness >10mm indicates splenomegaly in the cat
In cats, splenomegaly is almost always pathologic
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31. Tips – Spleen Ultrasound
Splenic veins are less plentiful than hepatic veins
Splenic veins more prominent with passive congestion
Body and tail are very mobile – location can vary
Can go along the greater curvature, so the tail falls near the right kidney
Can go along the left body wall, so the tail falls near the bladder
If marked splenomegaly, can fold over so that the tail falls back near the left kidney and the head of the spleen
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32. Tips – Spleen Ultrasound
Hilus identified by the hypoechoic “Y” formed by the splenic vein (“whale tail” sign)
Try right lateral recumbency if having difficulty distinguishing liver from spleen
When determining whether a mass arises from the spleen or is adjacent to the spleen, look at the capsule
Splenic mass displaces the hyperechoic capsule outward
Splenic capsule shows up best when perpendicular to ultrasound beam
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33. Tips – Spleen Ultrasound
DDx focal lesions in the spleen:
Cyst, abscess (peliosis), granuloma
Gas is tip-off for abscess (acoustic shadow)
Necrotic tumor can look like an abscess
Neoplasia – target lesions more likely metastatic
malignant – primary or metastatic
Benign – myelolipoma, fibroma
Hematoma, extramedullary hematopoiesis
Nodular hyperplasia, lymphoid hyperplasia
Infarct (wedge shaped)
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34. Tips – Spleen Ultrasound
DDx diffusely hypoechoic splenomegaly:
Nodular hyperplasia
Extramedullary hematopoiesis
Passive congestion
Lymphoid hyperplasia
Infection – bacterial, rickettsial, fungal
Immune mediated disease
Lymphoma, mast cell tumor, myeloproliferative disease
Irregular splenic capsule with no focal lesions most often due to nodular hyperplasia
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35. Tips – Spleen Ultrasound
DDx honeycomb splenomegaly:
Lymphoma is most common
Mast cell tumor
Myeloproliferative disease
Splenic thrombus should
Increase index of suspicion
For lymphoma
Black halo around the
spleen can indicate subscapsular hemorrhage (trauma)
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36. Pitfalls – Spleen Ultrasound
Make sure you follow the head of the spleen by fanning up under the left ribcage until it disappears
Spleen will appear largest here
Try standing if you can’t reach the edges of the spleen head
Do not misinterpret this as a mass
Masses are usually abnormal in echotexture and echogenicity
Hilar hyperechoic tissue is often a benign myelolipoma
Can’t differentiate benign vs. malignant on ultrasound
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37. Pitfalls – Spleen Ultrasound
Can’t always detect diffuse disease based on echogenicity changes
Do a fine needle aspiration cytology
FNA of spleen indicated for any chronically ill dog
Can’t reliably assess spleen size except marked enlargement in dogs
Beware aspirating the hypoechoic nodule in the liver and the spleen
Risk of hemorrhage
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38. Gary Kniffin – Round Rock, TX
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39. Summary PowerPoint – Ultrasound of the Spleen
.pdf of PowerPoints – Ultrasound of the Spleen (1 and 6 slides per page)
Spleen Ultrasound TIPs Sheet
Animated PowerPoint – Scanning the Spleen
Videos: Oncura - Ultrasound of the Spleen
(no audio), Video Case Examples
Hidden slides: indications, patient prep,
Transition adjustments

40. Acknowledgments Stephanie Lisciandro, ACVIM (Internal Medicine)
Chapter 4: Focused or COAST3 – Spleen Focused Ultrasound Techniques for the Small Animal Practitioner Editor Greg Lisciandro
Bob Cole, ACVR
Auburn University
The Academy of Veterinary Imaging
2409 Avenue J, Suite C Arlington, TX (800)

41. Acknowledgments John Mattoon, Danelle Auld, Thomas Nyland
Chapter 4: Abdominal Ultrasound Scanning Techniques Small Animal Diagnostic Ultrasound Editors Nyland and Mattoon – 3rd Edition 2014
Thomas Nyland, John Mattoon, Eric Herrgesell. Erik Wisner
Chapter 7: Spleen Small Animal Diagnostic Ultrasound Editors Nyland and Mattoon – 3rd Edition 2014
John P. Graham, MVB, MSc, DVR, MRCVS
Diplomate, ECVDI, Diplomate, ACVR Diagnostic Imaging in Dogs and Cats Nestle Purina – Clinical Handbook Series