Contrast Enhanced Sonography of Focal Splenic Lesions with a Second-Generation Contrast Agent

Abstract

Contrast enhanced sonography (CES) of second generation contrast media have shown a spleen-specific uptake of the microbubble contrast agent. The aim of this study was to investigate the ability of a second generation contrast agent to enhance splenic lesions. From October 2003 to September 2004, 46 consecutive patients with focal (peri-) splenic lesions on B-mode sonography were studied by CES using a transpulmonary second-generation contrast agent (SonoVue). Data were retrospectively evaluated. Diagnosis of the patients were infarction (n = 9), lymphoma (n = 7), metastasis (n = 6), injury (n = 4), haemangioma/splenoma (n = 6), accessory spleen (n = 3), cyst (n = 2), and unknown cause (n = 9). Diagnosed of splenic lesions was confirmed by histology (n = 5), contrast enhanced computed tomography (n = 25), MRI (n = 4), scintigraphy (n = 1), and follow up (n = 38). Extent of enhancement (EE) was evaluated during the arterial phase (5-30 s) and the parenchymal phase (3-5 minutes): EE of focal splenic lesions was determined using the surrounding splenic tissue as an in vivo reference, and classified as anechoic vs. hypoechoic vs. isoechoic vs. hyperechoic vs. mixed. The contribution of CES to the final diagnosis was classified as low, helpful or highly necessary. In all but one patient enhancement of normal splenic tissue occurred. During the arterial and parenchymal phase, lesions were found to have anechoic 10/10, hypoechoic 12/24, isoechoic 12/7, hyperechoic 7/0 and mixed enhancement 5/5, respectively. Value of CES for final diagnosis was low n = 24 (52%) (7 lymphomas, 6 metastases, 2 cysts, 9 unknown), helpful n = 9 (20%) (4 infarctions, 2 ruptures, 3 accessory spleens) and highly necessary n = 13 (28%) (5 infarctions, 2 ruptures, 6 haemangiomas/splenomas). Contrast-enhanced sonography is of diagnostic value in subgroups of patients with (peri-)splenic lesions (48%): including splenic infarction, splenic rupture, splenic haemangioma/splenoma, and accessory spleen.