Use of Contrast‐enhanced Ultrasound for Characterization of Focal Splenic Lesions

Abstract

Contrast-enhanced ultrasound was used to study focal and multifocal lesions of the spleen in 26 dogs and two cats affected by 11 benign and 18 malignant splenic diseases. A second-generation microbubble contrast medium (Sonovue) was injected into the cephalic vein and enhancement patterns were subjectively described and time intensity curves calculated. Final diagnosis was obtained by histopathologic examination after splenectomy (n=19) or by needle aspiration and sonographic follow-up after 4 and 8 weeks (n=9). Contrast-enhanced ultrasound parameters, improving the characterization between benign and malignant lesions, were established. The most useful criterion was the hypoechogenicity of the lesion in the wash-out phase combined with the presence of tortuous feeding vessels, which was observed in association with malignancy. All malignant lesions were hypoechoic to the surrounding spleen 30s after starting the contrast medium injection. Lymphosarcoma and hemangiosarcoma had characteristic perfusion patterns. Lymphosarcoma had rapid time to peak and early wash-out phase with a honeycomb pattern during the wash-out. Hemangiosarcomas were large nonperfused masses in all phases surrounded by hypervascular splenic parenchyma. Benign lesions except one hematoma and a benign histiocytoma had the same perfusion pattern as the surrounding spleen. Ultrasonographic and contrast-enhanced ultrasound findings of an accessory spleen are reported. Contrast-enhanced ultrasound can improve the characterization of focal or multifocal lesions of the spleen.

The use of contrast-enhanced ultrasound with a second generation contrast medium: preliminary report in the dog

“…The results of the liver, splenic and lymph node lesions are concordant with the literature (Salwei et al 2003;O'Brien et al 2004;Salwei et al 2005;Rossi et al 2008). No references for granulomas and lung lesions are available.…”

“…This technique is based principally on the transmission of the specific resonance frequency of the sulphur hexafluoride microbubbles and the selective registration of the harmonic frequencies produced. This allows a significant reduction of the insonation power, with reduction of the non-linear harmonic behaviour of the stationary tissues (Quaia 2007;Rossi et al 2008).…”

“…In human medicine it is routinely used to characterize liver lesions (Quaia 2007;Rossi et al 2008), while in veterinary medicine it has been recently used in small animals to study lymphomatous lymph nodes as well as lesions of the liver and spleen (Salwei et al 2003;O'Brien et al 2004;Salwei et al 2005;Rossi et al 2008). Second generation microbubble contrast agents present a diameter less than red blood cells and are composed of a shell of biocompatible materials and a low-solubility filling gas.…”

“…Second generation microbubble contrast agents present a diameter less than red blood cells and are composed of a shell of biocompatible materials and a low-solubility filling gas. They are stable in the peripheral and pulmonary circulation and their non linear oscillation can be imaged in real time and the perfusion of focal lesions can be compared with the surrounding tissue (Quaia 2007;Rossi et al 2008). Contrast-specific ultrasound techniques used with second generation contrast agents consist of low transmit power insonation in order to minimise the destruction of the microbubbles and to produce harmonic frequencies due to their non-linear physical behaviour, in which the degree of expansion is greater than its compression (Quaia 2007).…”

Role of strain elastography in differentiating malignant hypoechoic splenic lesions in dogs: Preliminary results

“…The prevalence of benign versus malignant lesions in our sample (frequency respectively of 67% and 33%) is consistent with other studies about the same subject (Rossi et al, 2008;Christensen et al, 2009;Watson et al, 2011;Cole et al, 2012;Hayes & Ladlow, 2012). Nodular hyperplasia was the most represented lesion (13 of 24 lesions, 54%), while haemangiosarcoma was the most represented between between malignant lesions (6 of 8, 75%).…”