Value of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Focal Splenic Lesions

Abstract

Purpose To identify and validate contrast-enhanced ultrasound (CEUS) features for differentiating malignant from benign splenic lesions. Patients and Methods Splenic lesions in 123 patients who underwent conventional ultrasound (B-mode US) and CEUS were included in this study. Two radiologists evaluated the sonograms of B-mode and CEUS. Statistical analysis was performed to identify significant imaging predictors for splenic malignant lesions. Two other radiologists independently reviewed B-mode and CEUS sonograms and diagnosed the lesions based on proposed criteria as 1) benign, 2) probably benign, 3) probably malignant or 4) malignant. The diagnostic efficiency between B-mode US and CEUS was compared. Results Common imaging findings of malignant lesions included hypoechoic, ill-defined margin, absence of cystic/necrotic portion, presence of splenomegaly on B-mode US, and hypoenhancement, rapid washout and presence of intralesional vessels on CEUS ( P < 0.05). Among them, three independent features were identified using multivariate logistic regression analysis: hypoechoic pattern, hypoenhancement pattern and intralesional vessels. When three of these findings were combined as a predictor for splenic malignant lesions, 22 (55.0%) of 40 malignant splenic lesions were identified with a specificity of 100%. The diagnostic performance of two readers using receiver operating characteristic curve analysis was 0.622 and 0.533, respectively, for B-mode US, which was significantly improved to 0.908 and 0.906 for CEUS ( P < 0.001). The degree of other diagnostic efficiency and inter-reader agreement also increased with CEUS compared to B-mode US. Conclusion CEUS may provide more useful information than B-mode US and improve the diagnosis efficiency for distinguishing malignant from benign splenic lesions.

Contrast-Enhanced Ultrasound Imaging Features of Focal Splenic Tuberculosis

“…However, 1 of the 22 cases was initially mistaken for a malignant lesion due to its rapid hyper-enhancement in the arterial phase followed by rapid wash-out, and ultimately was proven to be splenic TB by surgical histopathology. This enhancement pattern was inconsistent with the results from a previous study, which demonstrated that splenic TB lesions generally presented persistent enhancement during the intermediate parenchymal phase, and the rapid wash-out pattern was common in malignant splenic lesions but was rare in benign lesions [ 10 , 21 ]. We assumed that this unusual enhancement pattern is be likely associated with the neovascularization and the formation of arterio-venous fistula involved in splenic TB [ 20 ].…”

“…Studies demonstrated that CEUS can differentiate between benign and malignant splenic lesions and reported that the benign splenic lesions typically showed iso-enhancement or hyper-enhancement in the arterial phase followed by slow and incomplete wash-out, while malignant lesions initially showed slight hypo-enhancement followed by rapid and complete wash-out [ 10 , 20 ]. The iso-enhancement or hyper-enhancement of benign splenic lesions can reflect their rich vascular structures and enhanced arterial supply.…”

“…The non-enhanced splenic TB needs to be differentiated from the splenic infarct and splenic cystic lesions. It was reported that the splenic infarct generally showed a wedge-shape non-enhancement, and the splenic cystic lesions showed anechoic and thin cystic wall-like enhancement as detected by conventional US and CEUS [ 10 , 11 ]. Therefore, hypoechoic round splenic lesions with non-enhancement during all phases of CEUS examination are highly indicative of splenic TB.…”

The Role of Contrast-Enhanced Ultrasound in Differentiating Splenic Tuberculosis From Splenic Lymphoma

“…The display rate of 2D US for splenic tuberculosis is already extremely high. CEUS has little value in improving the display rate of splenic tuberculosis, but it is superior to 2D US in evaluating the internal blood supply to the lesion ( 9 – 12 ). CEUS of splenic tuberculosis showed that the lesions were mostly non-enhanced ( Figure 4 ) ( 13 ).…”

Applications of Contrast-Enhanced Ultrasound in Splenic Studies of Dogs and Cats

“…CEUS has been shown to be a particularly valuable tool for splenic analysis, with the ability to determine and monitor alterations in the size, presence, and character of focal lesions, as well as detect specific alterations in its normal vascular pattern [ 14 , 15 , 16 , 17 ]. Indeed, in the last 20 years, the use of CEUS techniques for the examination of the spleen in humans has been increasingly pursued and several guidelines [ 16 ] and specific studies have arisen [ 16 , 17 ]. However, there are limited studies and reference guides to describe the use of this method for characterizing splenic lesions in veterinary practice.…”