Diagnostic performance of different imaging modalities for splenic malignancies: A comparative meta-analysis

Abstract

Background and objectives: The spleen hosts both benign and malignant lesions. Despite multiple imaging modalities, the distinction between these lesions poses a diagnostic challenge, marked by varying diagnostic accuracy levels across methods. In this study, we aimed to evaluate and compare the diagnostic performance of various imaging techniques for detecting malignant splenic lesions.

Methods: Following PRISMA guidelines, we searched PubMed, Scopus, and Web of Sciences databases for studies evaluating imaging techniques in detecting malignant splenic lesions. Data extraction included diagnostic accuracy metrics, and methodological quality was assessed using QUADAS-2. Diagnostic Test Accuracy meta-analyses were conducted using R (version: 4.2.1). Subgroup analyses and meta-regression were performed to compare different modalities and clinical settings.

Results: Our study included 28 studies (pooled sample size: 2358), primarily using retrospective designs with histopathology as the reference standard. PET scan demonstrated the highest diagnostic accuracy (AUC: 92 %), demonstrating a sensitivity of 93 % (95 % CI: 80.4 % - 97.7 %) and a specificity of 82.8 % (95 % CI: 71.1 % - 90.4 %). Contrast-enhanced ultrasound (CEUS), Contrast-enhanced CT scan, and contrast-enhanced MRI also showed impressive performance with AUCs of 91.4 %, 90.9 %, and 85.3 %, respectively. Differences among these modalities were not statistically significant, but they outperformed non-contrast-enhanced methods. PET and CEUS exhibited higher specificity for lymphoma cases compared to studies including other malignancies.

Conclusion and clinical implications: Overall, PET emerges as the best modality for splenic malignancies, and CEUS and CE-MRI show promise as potential alternatives, notably due to their reduced radiation exposure. Further research is essential for precise malignancy differentiation.

Keywords: CT scan; MRI; PET; Splenic malignancy; Ultrasound.

Fig. 1

Examples of malignant splenic lesions identified through contrast-enhanced computed tomography (CT) and Magnetic Resonance Imaging (MRI). a) Axial contrast-enhanced CT scan of a 16-year-old female patient, revealing multiple hypodense lesions in the spleen and liver. Biopsy confirmed angiosarcoma. b) T2w MRI of a 21-year-old female patient, revealing multiple hypointense lesions in the spleen and liver. Biopsy confirmed angiosarcoma. c) Axial CT scan of a 56-year-old female patient demonstrating a 44 ×49 mm hypodense mass at the upper pole of the spleen. Subsequent Positron Emission Tomography (PET) scan uptake is suggestive of lymphoma, which was histopathologically confirmed. d) Axial CT scan of a 49-year-old male patient displaying multiple hypodense lesions within the spleen accompanied by splenomegaly, indicative of Hodgkin lymphoma, which was histopathologically confirmed. e) Portal phase axial CT scan of a 59-year-old female patient, revealing multiple hypodense lesions in the liver and spleen, indicative of lymphoma, which was clinically confirmed. f) Axial CT scan of a 58-year-old male patient showing a hypodense lesion with irregular borders in the spleen's posterior aspect, which was found in annual follow-up his colon cancer. Subsequent biopsy confirmed metastasis.

Fig. 2

Study selection process depicted by PRISMA flowchart.

Fig. 3

Summary results of critical risk of bias assessment using the QUADAS-2 tool.

Fig. 4

Summary receiver operating curve (SROC) plot for studies on primary included modalities, stratified by modality type, along with 95 % confidence regions and study-specific point estimates. CE: Contrast-enhanced. US: Ultrasound. SROC: Summary receiver operating curve.

Fig. 5

Paired forest plots of sensitivity and specificity of random effects bivariate-model meta-analysis of diagnostic accuracy of PET in detecting splenic malignancies. FSL: Focal Splenic Lesions. S/B: Spleen to bone marrow ratio. S/L: Spleen to liver ratio.

Fig. 6

Summary receiver operating curve (SROC) plot for included PET studies, along with 95 % confidence regions, study-specific point estimates, and prediction region. SROC: Summary receiver operating curve.

Fig. 7

Paired forest plots of sensitivity and specificity of random effects bivariate-model meta-analysis of diagnostic accuracy of CT in detecting splenic malignancies. CE: Contrast-enhanced. ONHES: Obliteration of normal heterogeneous enhancement of the spleen. PC: Peritoneal carcinomatosis. SI: Splenic Index.

Fig. 8

Summary receiver operating curve (SROC) plot for included CT studies, along with 95 % confidence regions, study-specific point estimates, and prediction region SROC: Summary receiver operating curve.

Fig. 9

Paired forest plots of sensitivity and specificity of random effects bivariate-model meta-analysis of diagnostic accuracy of MRI in detecting splenic malignancies, stratified by contrast enhancement status. The between-subgroup difference statistics are derived from meta-regression using the bivariate Reitsma model. CE: Contrast-enhanced. PC: Peritoneal carcinomatosis. Sen: Sensitivity. Spe: Specificity.

Fig. 10

Summary receiver operating curve (SROC) plot for included MRI studies, stratified based on contrast enhancement status, along with 95 % confidence regions and study-specific point estimates. CE: Contrast-enhanced. SROC: Summary receiver operating curve.

Fig. 11

Paired forest plots of sensitivity and specificity of random effects bivariate-model meta-analysis of diagnostic accuracy of ultrasound in detecting splenic malignancies, stratified by contrast enhancement status. The between-subgroup difference statistics are derived from meta-regression using the bivariate Reitsma model. CE: Contrast-enhanced. Sen: Sensitivity. Spe: Specificity.

Fig. 12

Summary receiver operating curve (SROC) plot for included ultrasound studies, stratified based on contrast enhancement status, along with 95 % confidence regions and study-specific point estimates. CE: Contrast-enhanced. SROC: Summary receiver operating curve. US: Ultrasound.

Fig. 13

Summary receiver operating curve (SROC) plot for studies using contrast-enhanced (CE) modalities, stratified by modality type, along with 95 % confidence regions and study-specific point estimates. CE: Contrast-enhanced. US: Ultrasound. SROC: Summary receiver operating curve.