What are the findings of an ultrasound examination for splenic trauma?

From the Guidelines

Ultrasound examination, specifically the focused assessment with sonography for trauma (FAST) protocol, is highly recommended for initial evaluation of splenic trauma in emergency settings. The choice of diagnostic technique at admission must be based on the hemodynamic status of the patient 1. E-FAST is effective and rapid to detect free fluid, with a sensitivity up to 91% and a specificity up to 96% 1. For a more detailed evaluation, a comprehensive abdominal ultrasound should be conducted using a 3.5-5 MHz curvilinear transducer. The patient should be positioned supine or in right lateral decubitus to optimize splenic visualization. The sonographer should systematically scan through the entire spleen in multiple planes, looking for parenchymal heterogeneity, subcapsular hematomas, or lacerations which appear as hypoechoic or anechoic areas within the splenic tissue. Color Doppler should be employed to assess vascular integrity and identify active bleeding.

Some key points to consider when using ultrasound for splenic trauma evaluation include:

• The use of Doppler US and contrast-enhanced US to evaluate splenic vascularization and in follow-up 1
• The limitations of ultrasound in grading splenic injuries and potentially missing small lacerations
• The importance of considering the patient's hemodynamic status when choosing a diagnostic technique

If the patient is hemodynamically stable and splenic injury is suspected despite negative or inconclusive ultrasound findings, a contrast-enhanced CT scan should follow for definitive evaluation and injury grading, which will guide management decisions between conservative treatment and surgical intervention 1. CT scan with intravenous contrast is the gold standard in hemodynamically stable or stabilized trauma patients, with a sensitivity and specificity for splenic injuries near to 96–100% 1.

From the Research

Ultrasound Exam of Trauma in Spleen

• The use of ultrasound in assessing splenic trauma is a valuable tool, particularly for rapid identification of hemoperitoneum 2.
• A study published in 2005 highlights the importance of ultrasound in evaluating blunt trauma to the spleen, showcasing various ultrasonographic appearances of the traumatized spleen 3.
• Contrast-enhanced sonography has been shown to be a promising tool in the assessment of splenic trauma, correlating better than unenhanced sonography in detecting injuries and estimating their extent 4.
• Key findings that can be identified through ultrasound include hemoperitoneum, perisplenic clots, splenic infarctions, and parenchymal traumatic lesions 4.
• The effectiveness of ultrasound can be increased with the use of contrast-specific sonography and a second-generation contrast medium, allowing for better detection of subtle splenic injuries 4.

Comparison with Other Imaging Modalities

• Computed Tomography (CT) remains the gold standard in blunt abdominal trauma, but ultrasound continues to play an important role in assessing the traumatized spleen 3.
• A study published in 2012 found that CT imaging without intravenous contrast (DRY imaging) has a low sensitivity in detecting splenic parenchymal injury, but can still provide high sensitivity for detecting splenic injury when less-specific radiographic findings are incorporated 5.
• The use of contrast-enhanced CT is preferred for detecting splenic injury, but in patients with contraindications to intravenous contrast, DRY imaging or ultrasound may be alternative options 5, 2.

Clinical Implications

• Accurate identification and conveyance of imaging findings to the multidisciplinary trauma team are crucial for guiding management and treatment of splenic trauma 6.
• The Association for Surgery for Trauma (AAST) Organ Injury Scale (OIS) is commonly used to stratify injury severity and guide management, with recent updates taking into consideration splenic vascular injuries 6.