Spleen Flashcards
USF of accessory spleen
Best diagnostic clue: Small para-splenic nodule with same echo pattern as the main spleen
• Well-defined, round to ova], located close to splenic hilum with sonographic appearance similar to main spleen
• Accessory spleens may enlarge with splenomegaly
Checklist for accessory spleen
Accessory spleen may hypertrophy after splenectomy and is responsible for recurrence of hematological disorders
USF of splenomegaly
Normal spleen in adult measures up to 12 cm; enlarged if it is 13 cm or longer
• In children, splenomegaly should be suspected if the spleen is more than 1.25x longer than the adjacent kidney
• Splenomegaly with altered parenchyma] echogenicity is seen in different etiological conditions
• SMG with norma] echogenicity • Infection, congestion (porta] hypertension), early sickle cell disease
• Hereditary spherocytosis, hemolysis, Felty syndromerheumatoid arthritis (RA)and splenomegaly
• SMG with hyperechoic pattern
• Metastases, leukemia, post-chemotherapy, post-radiation therapy
Malaria, tuberculosis, sarcoidosis, polycythemia
• SMG with hypoechoic pattern
• Metastases, lymphoma, multiple myeloma, chronic lymphocytic leukemia
• Best imaging tool: Ultrasound for confirmation of SMGand detection of focal lesions, CT allows better characterization of some lesions while MR preferred for hemorrhage or siderosis
Checklist for splenomegaly
CHECKLIST
• SMG, most common cause of left upper quadrant mass
• SMG, secondary to underlying condition
•uscan confirm presence of enlarged spleen or space occupying lesions within spleen
• CT&MR can further characterize abnormalities
• Radioisotope scanning can provide functional information
US findings of spleen cyst lesions
Best diagnostic clue: Anechoic sharply-defined spherical lesion with posterior acoustic enhancement
• Location: Usually subcapsular (65%)
• Congenital: Anechoic, smooth borders, epithelial or endothelial lining, non-detectable walls ± trabeculation (36%), posterior enhancement
• Post-traumatic: No cellular lining, small, anechoic or mixed with internal echoes, echogenic wall, ± calcification, ± trabeculation of cyst wall (15%)
• Infectious cysts (echinococcus cyst ± internal small daughter cysts & floating membranes ± calcification, hydatid sand)
• Other: Pancreatic pseudocyst extending into spleen, liquified hematoma, liquified splenic abscess (solitary or multiple)
Reliable differentiation between true cysts and acquired cysts is not always possible by ultrasound
• Ultrasound guided diagnostic aspiration can be safely performed: Aspiration yields clear watery fluid or brownish fluid due to previous hemorrhage
Checklist for cyst spleen lesions
Congenital: Large, well-defined with thin wall & no rim
• Acquired (post-traumatic): Usually small, sharply-defined, often anechoic with thick wall ± calcification
USF of splenic rumours
Best diagnostic clue: Solitary or multiple, solid or cystic splenic masses
Haemangioma
Variable size & echogenicity, well defined hyperechoic solid to mixed to purely cystic lesion
• Hamartoma • Well-defined, homogeneous echogenic mass, good through transmission & posterior enhancement • Non-vascular on color Doppler
• Lymphoma • US pattern corresponds to three macroscopic patterns; diffuse/infiltrative, miliary/nodular, hypoechoic/cyst-like focal (without posterior acoustic enhancement) • “Indistinct boundary” echo pattern
Leukemia & myeloproliferative disorders • Diffuse enlargement of spleen with variable echogenicity, very rarely focal hypoechoic nodular lesions
Mets
Multiple focal lesions with variable size & appearance; iso-/hypo-/hyperechoic
Checklist for splenic tumour
Considerable overlap in US findings; reliable differentiation between different splenic neoplasms on imaging is not always possible, requires biopsy
USF of splenic calcifications
Hyperechoic foci with posterior acoustic shadowing
• Early calcification mayor may not produce shadowing
• Calcified lesions represent benign etiology: Chronic granuloma, hamartomas, organized hematoma, cyst
• Curvilinear wall/rim calcification: Hydatid cyst, simple cyst
• Calcified intrasplenic pseudoaneurysm (rare)
Vascular calcification: Linear along the vessel wall/calcified thrombus
• Color flow along linear vascular calcification
• “Twinkling” artifact: Color signals posterior to calcification
Checklist for splenic calcifications
Calcified splenic lesions may be safely followed up with serial USG examinations as they are unlikely to represent lesions requiring treatment
USF for splenic vascular disorders
Acute infarct: Hypoechoic region in splenic parenchyma with absent flow on CD exam
• Grayscale findings may not appear for 24-48 hrs after loss of blood flow
• Chronic infarct: Linear or rounded echogenic region with “divot” on surface of spleen, scarring
• Acute SAocclusion: SAvisible but no blood flow in part or all of lumen
• Chronic SAocclusion: Non-visualization of all or part of SA,with possible visualization of collaterals
• Acute SVthrombosis (ASVT):SVvisualized but no flow on CD examination
• ASVT(note): Visualization of blood flow in splenic hilar branches does not exclude SVthrombosis
Chronic SVthrombosis (CSVT): Non-visualization of part or all of SV (scarred)
• CSVTclassical findings: Massive left-sided venous collaterals (splenogastric or splenorenal) without findings indicative of portal hypertension
Checklist for splenic vascular
Infarction: Hypoechoic region with grayscale US accompanied by absence of flow with CD imaging
• SVocclusion: Isolated, large splenic collaterals
