Splenic ultrasound

Splenic ultrasound is a non-invasive diagnostic imaging method that uses high-frequency sound waves to visualize and assess the size, shape, structure, and potential abnormalities of the spleen.

Indication

• trauma: splenic injuries resulting from accidents, sports injuries, or any other form of trauma can lead to life-threatening internal bleeding. A spleen ultrasound aids in evaluating the extent of injury and monitoring for any complications ¹

• Infection: ultrasound imaging can help identify abscesses or other infectious complications in the spleen that might require drainage or surgical intervention ²

• splenomegaly: an enlarged spleen (splenomegaly) can be detected using ultrasound imaging, assisting doctors in identifying underlying causes such as liver disease, blood disorders, or infections ³

• hematologic disorders: patients with blood disorders like thrombocytopenia (low platelet count), anemia (low red blood cell count), or leukopenia (low white blood cell count) may undergo spleen ultrasound to evaluate any abnormal changes in the organ which contribute to these conditions ⁴

• neoplastic lesions: spleen ultrasound can help detect tumors or masses within the spleen, both benign and malignant, as part of an overall cancer evaluation and management plan ⁵

• infarction: patients with symptoms suggestive of splenic infarction, such as acute abdominal pain and fever, may undergo a spleen ultrasound to assess the blood flow within the organ and detect any areas of tissue death caused by insufficient oxygen supply ⁶

• pre-operative evaluation: prior to undergoing certain surgeries that require removal or alteration of the spleen (splenectomy), a spleen ultrasound can assess the organ's size, shape, and any possible anomalies that could affect the surgical procedure ⁷

• Post-operative follow-up: Ultrasound imaging can monitor the recovery process after surgery or treatment involving the spleen and detect any complications such as bleeding, fluid collection, or infection ⁸

Techniques

• patient Preparation: before performing a spleen ultrasound, the patient should fast for at least six hours to reduce the amount of gas in the abdomen that might interfere with the visualization of the spleen. The patient should lie on their back with their left arm raised above their head to provide better exposure of the spleen ⁹

• probe Selection: a high-frequency curvilinear transducer is typically used to perform a spleen ultrasound due to its ability to provide detailed images and cover a wide field of view. Alternatively, a low-frequency phased array transducer can be used in cases where there is difficulty scanning through the ribs or in larger patients ¹⁰

Normal Findings

• size: the spleen is considered to be within normal range if its longitudinal length measures up to 12 centimeters in adults

• shape: a healthy spleen typically presents an oblong or wedge-like shape with smooth borders and no irregularities

• texture: the parenchyma of a normal spleen displays a homogeneous echotexture, appearing slightly more hypoechoic (darker) than the liver on ultrasound images

• position: the spleen is expected to be located in the left upper quadrant of the abdominal cavity, nestled under the diaphragm and posterior to the stomach

• vascular Structures: the normal splenic artery and vein should be present without any signs of blockage or narrowing

• absence of abnormal masses: no cysts, tumors, or other masses should be detected within a healthy spleen on an ultrasound examination

• neighboring Organs: there should be no signs of abnormal interactions or complications involving neighboring organs such as the pancreas, colon, and left kidney

Pathologies

• splenomegaly: this condition refers to an abnormally enlarged spleen. The major causes can include infections (such as mononucleosis or malaria), hematological disorders (such as leukemia), and liver diseases (such as cirrhosis). Ultrasound findings typically reveal an enlarged spleen, with size exceeding 12 cm in length ³

• splenic Infarction: this is a rare condition caused by insufficient oxygen supply to the spleen, often due to a blockage in the splenic artery or vein. It can be triggered by complications such as blood clot formation or sickle cell disease. Spleen ultrasound might present wedge-shaped hypoechoic lesions, and may also show signs of splenic enlargement ⁶

• splenic Abscess: a collection of pus within the spleen usually occurs secondary to infection or trauma. Patients with compromised immune systems are more susceptible to this condition. On ultrasound, abscesses appear as hypoechoic or complex fluid-filled structures with irregular borders ¹¹

• splenic cysts: a fluid-filled sacs that develop inside the spleen. They can be categorized into primary (true) cysts which include epithelial cysts or parasitic (hydatid) cysts, and secondary (pseudo) cysts which occur following trauma or inflammation. Ultrasound images will show well-defined anechoic structures with thin walls that may vary in size from a few millimeters to several centimeters ¹²

• hematoma: This refers to a collection of blood within the spleen, often resulting from trauma or spontaneous bleeding. On ultrasound, hematomas will appear as hypoechoic, well-defined regions that may change their appearance and size over time, depending on the stage of hematoma evolution ¹³

• Neoplasms: Splenic tumors can be benign (e.g., hemangiomas, hamartomas) or malignant (e.g., lymphoma, metastatic cancer). Ultrasound plays a role in detecting such masses and assessing their characteristics. Hemangiomas typically appear as well-defined, hyperechoic lesions, while malignant tumors will present varying levels of echogenicity and irregular borders ⁵

• Congenital anomalies –:asplenia (absence of the spleen) or accessory spleens ²

Practical Points

• proper patient positioning and adequate gel application are crucial for quality imaging

• It may be challenging to visualize the entire spleen, especially in obese patients or those with gas-filled bowel loops obscuring the view. Techniques like the graded compression method can aid in better visualization

• adjacent organs such as the left kidney, stomach, and pancreatic tail should be carefully assessed for any potential pathology that may be causing symptoms

• comparison of splenic size should take into account patient demographics and body habitus, as normal spleen dimensions can vary significantly between individuals

• In case of ambiguous findings on the ultrasound examination, further imaging techniques like computed tomography (CT) or magnetic resonance imaging (MRI) may be required for a more accurate assessment ¹⁴