From the Guidelines
Ultrasound is the recommended initial diagnostic imaging modality for evaluating an enlarged spleen (splenomegaly). When a patient presents with suspected splenomegaly based on physical examination or clinical symptoms, an abdominal ultrasound should be performed first as it provides accurate measurement of splenic size, is readily available, cost-effective, and does not expose the patient to radiation 1. The normal adult spleen measures approximately 7-12 cm in length, and measurements exceeding this range confirm splenomegaly. Ultrasound can also help identify focal lesions within the spleen and evaluate surrounding structures.
Some key points to consider when using ultrasound for splenomegaly diagnosis include:
- The presence of portocollateral circulation on ultrasound is 100% specific for clinically significant portal hypertension (CSPH) 1
- Splenomegaly taken alone is a sensitive but nonspecific sign of portal hypertension (PH), however, when combined with platelet count and liver stiffness, it provides accurate data on the presence of CSPH/varices 1
- Ultrasound provides safe and inexpensive imaging evidence of morphological abnormalities associated with cirrhosis and PH 1
If ultrasound findings are inconclusive or additional information is needed, contrast-enhanced CT or MRI may be ordered as second-line imaging studies 1. These advanced imaging modalities provide more detailed information about splenic architecture, focal lesions, vascular abnormalities, and potential causes of splenomegaly. However, they should not be the first choice due to higher cost, limited availability, and radiation exposure (in the case of CT). Patients should be prepared for an ultrasound by fasting for 6-8 hours prior to the examination if possible, though this is not strictly necessary for evaluating the spleen alone.
In terms of specific patient populations, such as those with trauma, the choice of diagnostic technique at admission must be based on the hemodynamic status of the patient 1. For example, in hemodynamically stable patients, CT scan with intravenous contrast is the gold standard, while in unstable patients, E-FAST is effective and rapid to detect free fluid. Ultimately, the goal is to prioritize the patient's safety and provide the most accurate diagnosis possible, while minimizing risks and costs.
From the Research
Initial Diagnostic Imaging for Enlarged Spleen
- The initial diagnostic imaging for an enlarged spleen can be achieved through various modalities, including ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging 2, 3.
- Ultrasound is a useful means of noninvasively examining the spleen and can identify splenomegaly, accessory spleens, and focal splenic masses 2.
- Abdominal ultrasonography is recommended for confirmation of splenomegaly and can help assess for signs of systemic illness, liver disease, and anemia or other hematologic issues 4.
- The role of abdominal ultrasound in hematological diseases is significant, as it can help suspect hematological diseases and detect enlarged spleen, pathological lymph nodes, or other findings 5.
- Ultrasonography can be used to evaluate spleen size and express it as a spleen index (SI), which correlates well with the volumes of resected spleens 6.
Imaging Modalities
- Ultrasound (US) is a very useful means of noninvasively examining the spleen and can identify splenomegaly, accessory spleens, and focal splenic masses 2.
- Computed Tomography (CT) and MR imaging can be used as screening modalities for the spleen and can help in problem-solving, especially due to its free choice of the imaging plane and high resolution in contrast MR imaging 3.
- Splenic angiography has generally been replaced by CT, ultrasound, or MR and is now used as an interventional method 3.
Clinical Applications
- Abdominal ultrasonography is recommended for confirmation of splenomegaly and can help assess for signs of systemic illness, liver disease, and anemia or other hematologic issues 4.
- The detection of an enlarged spleen, pathological lymph nodes, or other findings may help to suspect hematological diseases 5.
- Ultrasonography can be used to evaluate spleen size and express it as a spleen index (SI), which correlates well with the volumes of resected spleens 6.