Stellenwert der kontrastmittelunterstützten Sonographie (KUS) in der Diagnostik von echoreichen Milzherden: Eine retrospektive klinisch-sonographische Studie

Purpose: Focal splenic lesions are rare. In the fundamental ultrasound they are mostly classified by their echogenicity. Differentiation according to their dignity is often difficult. Histological confirmation is usually not due to the supposedly benign etiology. The aim of this study was the detection of prognostically relevant factors for the differentation between benign and malignant focal splenic lesions. The characteristics of contrast enhanced ultrasound (CEUS) were analyzed using quantitative measurement methods. Material and methods: In the retrospective, clinical-sonographic study n=51 hyperechoic focal splenic lesions (26 women, 25 men) could be included. Sociodemographic, fundamental ultrasound morphological and contrast-specific data were collected. The enhancement of the contrast agent was quantitatively analyzed in 7 time intervals. The dignity of the lesions was performed in 14 patients (27.5 %) by histopathologic diagnosis and in 37 (72.5 %) patients by imaging follow-up investigations with measurement of the lesion size. Results: Both benign (n=34; 66.7 %) and malignant (n=17; 33.3 %) splenic lesions showed in the contrast enhanced ultrasound in the average a hypoechoic enhancement. In malignant splenic lesions, however, there was a significantly lower uptake of the contrast agent (p = 0.001) compared to benign splenic lesions. If the hyperechoic lesions showed revealed an isoechoic or a hyperechoic enhancement pattern in one or more time slots, this was highly significant for a benign lesion (p = 0.0004). A history of malignancy (p=0.01), an inhomogeneous splenic lesion in the fundamental ultrasound (p=0.02) and male gender (p=0.04) were significantly correlated with a malignant splenic lesion. Conclusion: Malignant lesions are often described in the literature with a pronounced hypoechoic enhancement compared to benign lesions. In this case, the quantitative analysis of CEUS can be helpful. However, there are still missing suitable cut-off-values for the differentiation between benign and malignant lesions. When the contrast enhancement, the presence of a malignant cancer in another organ, the homogeneity in the fundamental ultrasound and the patient’s sex are considered together, the classification of the dignity of a focal echogenic splenic lesion can succeed in many cases.