Application of Microflow Imaging in Neoplasm Diagnosis: A Systematic Review and Meta-analysis

Area of Science:

• Medical Imaging
• Oncology
• Diagnostic Accuracy

Background:

• Tumor angiogenesis is a key indicator of malignancy, but conventional ultrasound (US) faces limitations in differentiating benign from malignant lesions due to overlapping grayscale features and color Doppler flow imaging's (CDFI) inability to detect microvascular flow.
• Superb microvascular imaging (SMI) is an advanced US technique that uses adaptive algorithms to visualize intratumoral microvascular morphology and distribution with high resolution, potentially enhancing early tumor differentiation.

Purpose of the Study:

• To systematically assess and compare the diagnostic performance of SMI against conventional CDFI for distinguishing benign from malignant tumors using a meta-analysis of diagnostic test accuracy studies.

Main Methods:

• An extensive literature search was conducted across major databases (Web of Science, PubMed, Cochrane Library, Embase) up to February 26, 2025, focusing on studies evaluating SMI and CDFI for tumor diagnosis.
• Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool.
• Meta-DiSc 1.4 and STATA software were used for statistical analyses, including threshold effect testing, heterogeneity testing, and computation of pooled sensitivity, specificity, likelihood ratios, and diagnostic odds ratio (DOR). Summary receiver operating characteristic (SROC) curves were constructed.

Main Results:

• Twenty-eight studies were included, comprising 22 on superficial organ tumors (17 breast, 5 other) and 6 on abdominal organ tumors (5 kidney, 1 liver).
• Pooled analysis revealed that SMI achieved an overall sensitivity of 0.84 (95% CI: 0.80-0.87) and a specificity of 0.79 (95% CI: 0.74-0.84), with an area under the curve (AUC) of 0.88.
• Performance was consistent across superficial (AUC=0.89) and abdominal (AUC=0.89) organ tumors, with sensitivities of 0.84 and 0.83, and specificities of 0.79 and 0.81, respectively.

Conclusions:

• Superb microvascular imaging (SMI) demonstrates high sensitivity and specificity for differentiating benign from malignant tumors, outperforming conventional color Doppler flow imaging (CDFI).
• SMI represents a promising novel imaging technique with potential for clinical adoption in tumor diagnosis.
• Future research should focus on larger sample sizes for abdominal organs and detailed investigation of SMI performance across diverse lesion types.