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The finding of an inhomogeneous splenic parenchyma using B-mode ultrasound imaging represents a clinical problem for the ultrasound examiner. A distinction can basically be made between a focal and a diffuse inhomogeneity of the splenic parenchyma. In particular the sonographic pattern of a diffuse inhomogeneity of the splenic parenchyma may cause difficulties in clinical diagnosis.
The spleen is well suited for the new technology of contrast-enhanced ultrasound (CEUS).
The sulfur hexafluoride microbubble contrast media SonoVue® has shown spleen specific enhancement that lasts longer than five minutes (Lim et al., 2004).
The aim of this study was to evaluate the diagnostic value of CEUS in patients with the finding of an inhomogeneous splenic parenchyma using B-mode ultrasound imaging. For that purpose the sonograms and clinical data of 120 patients with a splenic inhomogeneity on B-mode ultrasound imaging followed by a CEUS examination during the time period from 2003 until 2010 were retrospectively analysed.
In this study the CEUS examination was considered to be of diagnostic value if a focal lesion could be detected only by the use of contrast medium, if a lesion visible on B-mode ultrasound imaging became more clearly demarcated from the surrounding splenic tissue after the administration of contrast medium and/or if a diagnosis could be made after CEUS examination.
In total CEUS was considered to be of diagnostic value in 90 of 120 patients (75 %). In 71 of 120 patients (59 %) a diffuse inhomogeneity of the splenic parenchyma was seen on B-mode ultrasound imaging. In accordance with the result of a pilot study carried out by Görg et al. (2006) the detection of focal splenic lesions using CEUS was succsessful in 44 % of the patients with a diffuse inhomogeneity of the splenic parenchyma.
Using B-mode ultrasound imaging a focal splenic lesion was suspected in 49 of 120 patients (41 %). After the administration of contrast medium focal lesions became more clearly demarcated from the surrounding splenic tissue in 98 % of the patients. Several previous studies (Catalano et al., 2003c; Peddu et al., 2004; Görg, 2005) have already demonstrated that in comparison with B-mode ultrasound imaging focal splenic lesions are visualized better and therefore detected more frequently by the use of CEUS.
In 87 of 120 patients (73 %) a diagnosis could be made after CEUS examination. The most common reason for an inhomogeneous splenic parenchyma on B-mode ultrasound imaging was splenic infarction.
Following the results of this study CEUS should be conducted after the finding of a focal or a diffuse inhomogeneity of the spleenic parenchyma using B-mode ultrasound imaging. This study like previous studies (von Herbay et al., 2006; Catalano et al., 2003c; Clevert et al., 2008) has shown that CEUS is of diagnostic value in patients with splenic infarction and splenic rupture. Consequently CEUS can be recommended in suspected cases. In particular in case of a diffuse inhomogeneity of the splenic parenchyma CEUS can be of diagnostic value. CEUS enhances the lesion-to-parenchyma-contrast and thus enabled in this study in 44 % of patients with a diffuse inhomogeneity of the splenic parenchyma in B-mode ultrasound imaging the detection of focal splenic lesions.
In this and previous studies it could not be clearly evaluated to what extent CEUS increases the diagnostic accuracy in patients with splenic lymphoma involvement, splenic metastases, Hypo-/Asplenia, splenic abscess and splenic sarcoidoses. Further studies with a larger number of cases and an uniform reference standard are necessary.