Conventional Ultrasound and Contrast-Enhanced Ultrasound in the Diagnosis of Splenic Diseases: A Systematic Review and Meta-analysis

Differentiating malignant from benign splenic lesions: a meta-analysis and pictorial review of imaging features

OBJECTIVES

Splenic lesions might exhibit overlapping imaging features, varying from benign entities like cysts and hemangiomas to malignancies such as lymphoma and angiosarcoma. This meta-analysis aims to delineate imaging characteristics that distinguish malignant from benign splenic lesions.

METHODS

Adhering to PRISMA guidelines, we searched PubMed, Scopus, and Web of Science for studies on imaging features differentiating malignant from benign splenic lesions. We extracted data on splenic pathology and imaging characteristics and assessed the methodological quality via QUADAS-2. Odds ratio meta-analyses were performed using STATA (Version 17.0, Stata Corp, College Station, TX).

RESULTS

Portal phase hypoenhancement, hypovascular enhancement pattern, diffusion restriction, and late phase hypoenhancement, with odds ratios above 10, highly indicate malignancy. Other features suggestive of malignancy include solid morphology, lymphadenopathy, presence of perisplenic fluid, arterial hypoenhancement, hypoechogenicity on ultrasound, splenomegaly, and presence of multiple lesions. In contrast, cystic morphology, hypervascular-washout and hypervascular-persistent pattern of enhancement, late phase hyperenhancement, anechogenicity on ultrasound, portal phase hyperenhancement, well-defined borders, and calcification are in favour of benign pathology.

CONCLUSION

The study underscores the critical role of contrast-enhanced and diffusion-weighted imaging in distinguishing malignant from benign splenic lesions, emphasizing the role of features like portal phase hypoenhancement and restricted diffusion in diagnosing malignancies. Additionally, the study emphasizes the value of contrast-enhanced ultrasound, which allows for the visualization of key contrast-enhancement patterns without the risk of ionizing radiation exposure.

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

Aim

To summarize the features of splenic tuberculosis and splenic lymphoma by contrast-enhanced ultrasound (CEUS) and examine the application of CEUS in differentiating splenic tuberculosis from splenic lymphoma.

Methods

The ultrasound and CEUS manifestations of 30 cases of splenic tuberculosis and 19 cases of splenic lymphoma were retrospectively analyzed, and the number of lesions, degree of splenomegaly, internal echogenicity, color blood flow signal, and CEUS manifestations of the two diseases were statistically determined.

Results

A significant difference was noted in the internal echogenicity between splenic tuberculosis and splenic lymphoma lesions, particularly the strip-shaped hyperechoic areas of the lesions. The ultrasound features of perisplenic, retroperitoneal, and superficial lymph node enlargement were found to overlap (p < 0.05). Splenic tuberculosis showed heterogeneous enhancement and non-enhancement, whereas lymphoma showed low enhancement and high enhancement, and CEUS findings were statistically significant in distinguishing both, p < 0.05.

Conclusion

Splenic tuberculosis is characterized by a lack of blood supply, mostly heterogeneous enhancement, and non-enhancement noted in CEUS. Splenic lymphoma lesions are often characterized by a rich blood supply and homogeneous enhancement on CEUS. CEUS can help identify the microcirculation of lesions in both patients with splenic lymphoma and patients with splenic tuberculosis. Thus, CEUS has great application value.

Contrast-Enhanced Ultrasound Imaging Features of Focal Splenic Tuberculosis

Background

The aim of this study was to characterize the contrast-enhanced ultrasound imaging features of focal splenic tuberculosis.

Material/Methods

We retrospectively analyzed the conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) imaging features of 22 patients with splenic TB confirmed by surgical histopathology or biopsy.

Results

Conventional US demonstrated that 15 of the 22 patients had a single lesion, while 7 had multiple lesions. The maximum diameter of the lesions ranged from 1.0 to 3.7 cm. Of the 22, 17 were detected with hypoecho and 5 were detected with complex echo by conventional US. Seven (7/22) were detected with blood flow signals by color Doppler flow image (CDFI). CUES demonstrated that 18 cases (81.8%, 18/22) began to enhance in the arterial phase, mostly followed by slow wash-out in the intermediate or late parenchymal phase, and 4 (18.2%, 4/22) presented with non-enhancement during all phases. The enhancement patterns were categorized into 4 types: Type I, homogeneous enhancement (2/22); Type II, rim-like enhancement (12/22); Type III, septation-like enhancement (4/22); and Type IV, non-enhancement (4/22).

Conclusions

CEUS showed that splenic TB lesions were enhanced in the arterial phase, followed by slow washed out or persistent enhancement in the intermediate and late parenchymal phases. The rim- or septation-like enhancement may be helpful for diagnosing splenic TB. The splenic lesions presenting round hypoecho by conventional US and complete non-enhancement by CEUS are highly suspicious of splenic TB.

WFUMB Position Paper-Incidental Findings, How to Manage: Spleen

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental Imaging Findings-The Role of Medical Ultrasound." IFs are less commonly encountered in the spleen than in many other abdominal organs but remain a frequent dilemma in clinical practice. A histological diagnosis is rarely necessary for patient management. Many IFs, such as secondary spleens and splenic cysts, are harmless and do not require any further investigation. The diagnosis of many other focal splenic lesions is, however, often problematic. The following overview is intended to illustrate a variety of incidentally detected spleen pathologies such as size variants, shape variants, secondary spleens, focal splenic lesions and splenic calcifications. It should aid the examiner in establishing the diagnosis. Moreover, it should help the ultrasound practitioner decide which pathologies need no further investigation, those requiring interval imaging and cases in which immediate further diagnostic procedures are required.