Spleen - Ultrasound Technique.

Ultrasonography The Spleen VCA 341 Dr. LeeAnn Pack lpack@upei.ca Spleen Indications      Splenomegaly Palpable splenic mass Cranial abdominal organomegaly Lethargy, collapse Anemia, abnormal RBC’s Spleen 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 Spleen Anatomy  Size of normal spleen variable – Assessed subjectively – Enlarged spleen may cross midline or extend caudally to the bladder  Parenchyma – Homogenous, finely textured  Echogenicity – Dog: – Cat: Spleen > liver > kidney Spleen = liver > kidney Spleen Normal Spleen Spleen Anatomy  Capsule – Smooth, regular, VERY echogenic  Splenic veins – Only other structure normally visualized – Poorly visualized except near hilus •“Whale tail” – Enlargement subjective  Hilus – Check for lymphadenopathy Spleen Splenic Hilus Spleen Pathology  Diffuse splenomegaly – Congestion – Torsion – Inflammation/septicemia – Neoplasia •Lymphosarcoma •Mast cell tumor – Phenothiazine tranquilizers & barbiturate anaesthetics – Extramedullary hematopoesis Spleen Pathology  Focal or multifocal splenic lesions – Hematoma – Infarcts – Cysts – Abscess – Nodular hyperplasia – Neoplasia •Hemangioma •Hemangiosarcoma Spleen 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 Spleen Non Homogenous Spleen Focal/Multifocal Lesions  More common than diffuse  Anechoic – Cysts •Hematoma/neoplasia  Hypoechoic – Neoplasia – Abscess – Acute infarct – Nodular hyperplasia Spleen Focal/Multifocal Lesions  Hyperechoic – Neoplasia – Abscess – Chronic infarct – Nodular hyperplasia  Mixed echogenicity – Neoplasia – Hematoma – Abscess – Nodular hyperplasia Spleen Splenic Mass Spleen Splenic Mass Spleen Splenic Infarct Spleen 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 Spleen Torsion Spleen Neoplasia  Lymphosarcoma – Diffuse or focal/multifocal – Hypoechoic or hyperechoic – Can appear normal  Hematoma, hemangioma, hemangiosarcoma – Unable to differentiate – Focal – Hypoechoic, hyperechoic or mixed Spleen Lymphosarcoma Spleen Hemangiosarcoma Spleen 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) Spleen 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 Spleen Definitive Diagnosis  Ultrasonic appearance of most splenic diseases non-specific  Consider history, signalment, clinical signs  Fine needle aspirate useful  Biopsy generally not performed Spleen Rupture  Free fluid within the abdomen – Often echoic (due to  blood cells) – May be anechoic  Most likely a tumor  Cannot rule out hematoma Spleen Thrombosis Spleen Splenic Thrombus Spleen Myelolipoma