The spleen, a lymphatic organ of mesodermal origin, consist of two histological compartments: the red and white pulp. Although the spleen is rarely the primary site of disease, it is often involved in inflammatory, hematopoietic, and metabolic disorders associated with immune and hematologic diseases.

Functions of the spleen overlap those of other body organs, making it possible for a person to live without a spleen. Physiologically, the four major functions of the spleen include reserving, filtering, producing, and defending blood products.Within the spleen, the red pulp is dedicated to filtration, the white pulp is dedicated to adaptive immunity, and the perifollicular zone which is located between red and white pulp—acts to connect both functions

Anatomical variants, such as notches, clefts, accessory spleen, splenanculi are considered normal variants and are easily recognised by thier identical signal intensity to the parent spleen across all imaging sequences.The absence of the spleen(asplenia) and the presence of more than one spleen (polysplenia) are rare and usually associated with other congenital abnormalities.

Spelnic lesions are often discovered incidentally and require careful imaging evaluation to guide treatment decisions. These lesions can be classified as either cystic or solid. For cytic lesions, identifying infectious causes is crucial, as they may lead to septicemia. While most incidental solid splenic lesions are benign, distinguishing aggressive malignant lesiosn is essential, as this can significantly impact management strategies. A commonly used imaging approach for evaluating splenic masses involves assessing the number and consistency of lesions, further refined by supplementary imaging features, to develop a practical differenctial diagnosis framework.

Imaging modalities that are used for characterisation are 

• Ultrasound scan
• Computed tomography(CT)
• Magnetic resonance imaging (MRI) 
• Nuclear medicine scan
•       Tc-99m sulfur colloid scan- For confirmation of ectopic spleen.
•       Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT -detecting splenic involvement by lymphoma