Ultrasonography The Spleen VCA 341 Dr. LeeAnn Pack lpack@upei.ca

Indications Splenomegaly Palpable splenic mass Cranial abdominal organomegaly Lethargy, collapse Anemia, abnormal RBC’s

Ultrasound Technique Left side of body Head of spleen Under border of rib cage on left Body & tail of spleen Along left body wall Ventral or lateral to left kidney Scan sagittal & transverse

Anatomy Size of normal spleen variable Parenchyma Echogenicity Assessed subjectively Enlarged spleen may cross midline or extend caudally to the bladder Parenchyma Homogenous, finely textured Echogenicity Dog: Spleen > liver > kidney Cat: Spleen = liver > kidney

Normal Spleen

Anatomy Capsule Splenic veins Hilus Smooth, regular, VERY echogenic Only other structure normally visualized Poorly visualized except near hilus “Whale tail” Enlargement subjective Hilus Check for lymphadenopathy

Splenic Hilus

Pathology Diffuse splenomegaly Congestion Torsion Inflammation/septicemia Neoplasia Lymphosarcoma Mast cell tumor Phenothiazine tranquilizers & barbiturate anaesthetics Extramedullary hematopoesis

Pathology Focal or multifocal splenic lesions Hematoma Infarcts Cysts Abscess Nodular hyperplasia Neoplasia Hemangioma Hemangiosarcoma

Diffuse Splenomegaly Diffuse increase in echogenicity uncommon Neoplastic (mast cell or lymphosarcoma) Diffuse decrease in echogenicity more common Congestion Extra-medullary hematopoesis Lymphosarcoma Inflammation/ septicemia Torsion Normal echogenicity can occur with lymphosarcoma & mast cell tumor Break this slide up

Non Homogenous

Focal/Multifocal Lesions More common than diffuse Anechoic Cysts Hematoma/neoplasia Hypoechoic Neoplasia Abscess Acute infarct Nodular hyperplasia

Focal/Multifocal Lesions Hyperechoic Neoplasia Abscess Chronic infarct Nodular hyperplasia Mixed echogenicity Hematoma

Splenic Mass

Splenic Mass

Splenic Infarct

Torsion Definitive diagnosis by ultrasound Characteristic appearance Severe, diffuse splenomegaly Hypoechoic Coarse & “lace-like” Venous blood flow absent on Doppler +/- hyperechoic venous thrombi Lymphosarcoma can appear similar Normal blood flow

Torsion

Neoplasia Lymphosarcoma Hematoma, hemangioma, hemangiosarcoma Diffuse or focal/multifocal Hypoechoic or hyperechoic Can appear normal Hematoma, hemangioma, hemangiosarcoma Unable to differentiate Focal Hypoechoic, hyperechoic or mixed

Lymphosarcoma

Hemangiosarcoma

Neoplasia Other neoplasms Mast cell tumor, leiomyoma, etc. Presence of peritoneal effusion not a good indication of malignancy Metastasis Lungs, liver, lymph nodes (splenic, hepatic, gastric)

Echogenic Focal Lesions Focal fat deposits Especially cats Surround hepatic veins (myelolipomas) Fibrosis & calcification Secondary to hematoma, chronic infarcts or granulomas (histoplasmosis) Primary or metastatic neoplasia

Definitive Diagnosis Ultrasonic appearance of most splenic diseases non-specific Consider history, signalment, clinical signs Fine needle aspirate useful Biopsy generally not performed Does this apply to neoplasms? Focal lesions? What exactly?

Rupture Free fluid within the abdomen Most likely a tumor Often echoic (due to  blood cells) May be anechoic Most likely a tumor Cannot rule out hematoma

Thrombosis

Splenic Thrombus

Myelolipoma