Laboratory Studies
No specific diagnostic laboratory studies for splenic infarction exist, though an elevated white blood cell count is not infrequent.
Imaging Studies
Computed tomography (CT), performed with intravenous (IV) nonionic contrast, is the current diagnostic modality of choice (see the image below). Before the CT era, the diagnosis of splenic infarction was most commonly made at laparotomy for an intra-abdominal catastrophe or on postmortem examination.
Splenic infarct. Computed tomography scan of a 51-year-old man following a motor vehicle accident. American Association for the Surgery of Trauma (AAST) grade III splenic injury, with active extravasation of contrast from the splenic parenchyma (the white area along the medial aspect of the spleen).
Magnetic resonance imaging (MRI), preferably performed with IV gadolinium contrast, is another useful modality that clearly identifies infarcted splenic parenchyma. Contrast-enhanced MRI and multidetector CT allow three-dimensional reconstructions in any plane (coronal, sagittal, or axial) to better visualize the classic appearance of wedge-shaped infarctions within the spleen.
Given the dual blood supply of the spleen, contrast-enhanced studies should be performed during a delayed phase so that the normal early archiform pattern of arterial splenic enhancement does not mask lesions or create pseudolesions.
Contrast studies should be performed during an appropriate delay (for patients with good cardiac reserve, 50 seconds is an acceptable scan delay) when most spleens will be in the uniform phase of enhancement. [19] These postcontrast scans clearly depict the classic segmental, wedge-shaped, low-attenuation defect. [20] Less frequently, the entire spleen may be infarcted, leaving only a rim of contrast-enhancing capsule. [21]
Other modes of diagnosis include radioisotope scans and ultrasonographic [22] (US) evaluation of the spleen. Angiography is indicated when a vascular lesion is suspected as the etiologic cause, as in cases of arterial embolization, or when it is necessary to manage segmental bleeding by embolization (see the images below).
Splenic infarct. Selective splenic arteriogram showing extravasation of contrast from the splenic artery at the splenic hilum prior to angioembolization (same patient as in the above image).
Computed tomography scan of the spleen 5 days after angioembolization of a bleeding splenic artery, showing partial splenic infarct (demonstrated by a lack of IV contrast enhancement of the lower pole of spleen). The patient experienced no adverse sequelae and fared well following his discharge to home 5 days after the embolization (same patient as in the above images).
US is useful in cases where the splenic parenchyma can be visualized. [23] Significant amounts of luminal bowel gas, as well as morbid obesity, render this modality less useful. In a retrospective study of 49 episodes of acute splenic infarction, Antopolsky et al found ultrasonographic scanning to be diagnostically useful in only 18% of patients. [18]
Histologic Findings
Pathologic examination of the resected spleen may provide information regarding the pathogenesis of the infarct (eg, evidence of septic or atheromatous emboli or the presence of an infectious etiology).
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Splenic infarct. Computed tomography scan of a 51-year-old man following a motor vehicle accident. American Association for the Surgery of Trauma (AAST) grade III splenic injury, with active extravasation of contrast from the splenic parenchyma (the white area along the medial aspect of the spleen).
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Splenic infarct. Selective splenic arteriogram showing extravasation of contrast from the splenic artery at the splenic hilum prior to angioembolization (same patient as in the above image).
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Computed tomography scan of the spleen 5 days after angioembolization of a bleeding splenic artery, showing partial splenic infarct (demonstrated by a lack of IV contrast enhancement of the lower pole of spleen). The patient experienced no adverse sequelae and fared well following his discharge to home 5 days after the embolization (same patient as in the above images).
