What is the appearance of a hematoma on an Ultrasound?
Hematomas are usually spherical or ovoid within the abdomen, and lentiform within the pleural space or abdominal wall.
They generally decrease in size with time, and usually have irregular walls. Hematomas contain a variable amount of internal echoes during the first month, and then gradually become anechoic.
The sonographic appearance is not specific; an abscess may have a similar appearance. An old, anechoic hematoma may contain a gelatinous material which cannot be aspirated.
On an ultrasound, a hematoma typically appears as a localized collection of blood within a tissue or organ. The appearance of a hematoma on ultrasound can vary depending on the age of the hematoma and the characteristics of the surrounding tissue. Here are some typical ultrasound findings for a hematoma:
- Echogenicity: In the acute phase, a hematoma may appear hypoechoic (darker) compared to the surrounding tissues due to the presence of fresh, liquid blood. As the hematoma progresses and undergoes changes, it may become more echogenic (brighter) and have a heterogeneous appearance.
- Shape and Margins: Hematomas can have various shapes and sizes depending on the location and extent of the bleeding. They may have irregular or well-defined margins, depending on the stage and organization of the hematoma.
- Fluid Collection: Hematomas often appear as fluid-filled collections on ultrasound. The size and shape of the fluid collection can help assess the extent of the hematoma.
- Doppler Imaging: Using Doppler ultrasound, blood flow within and around the hematoma can be evaluated. In the acute phase, there may be increased vascularity due to active bleeding. As the hematoma evolves and resolves, the vascularity may decrease.
- Surrounding Tissue Displacement: Depending on the location and size of the hematoma, it may cause displacement or compression of adjacent structures, such as blood vessels, organs, or tissues. This displacement can be visualized on ultrasound.
It’s important to note that the appearance of a hematoma on ultrasound can vary based on multiple factors, including the age of the hematoma, location in the body, and the specific characteristics of the ultrasound machine used. The interpretation of the ultrasound findings is best performed by a qualified healthcare professional, such as a radiologist or sonographer, who can correlate the ultrasound findings with the patient’s clinical history and perform further evaluation if necessary.
A hematoma may have a variety of appearances on an Ultrasound depending on when it is imaged.
If imaged acutely, a hematoma often appears as an ill-defined but predominantly hyperechoic collection.
A hematoma starts to resorb from the periphery inward, becoming smaller and more echogenic.
In the end, a residual anechoic fluid collection or seroma may persist indefinitely.
A subacute hematoma becomes more hypoechoic, although a heterogeneous appearance is common.
Hematoma of the liver usually results from trauma and is caused by bleeding into a tissue laceration. Iatrogenic causes, such as percutaneous needle biopsy, interventional radiology procedures involving catheters or wires, and biliary lithotripsy, are often involved.
Hepatic hematomas arising from spontaneous bleeding are rare. Hepatic hematoma appears as a well‐defined, round (intraparenchymal hematomas), or curvilinear (subcapsular hematomas) mass.