- Design
- Systematic review and diagnostic accuracy meta-analysis
- Population
- 36 studies, 4,530 renal masses
- Primary outcome
- Sensitivity and specificity for renal malignancy
- Effect
- Sensitivity 94% (91-96%); specificity 85% (79-89%); cystic sensitivity 99%
This meta-analysis, published in April 2026, pooled 36 studies of 4,530 renal masses (3,221 malignant, 1,309 benign) assessed with contrast-enhanced ultrasound.
Pooled sensitivity for malignancy was 94% (95% CI 91% to 96%) and specificity 85% (79% to 89%). Sensitivity was higher for cystic masses (99%) than solid ones (88%), with slightly lower specificity for cystic masses (80% vs 87%). Heterogeneity between studies was high.
For nephrologists, the practical value is in patients with reduced kidney function who have an indeterminate mass, where iodinated contrast CT or gadolinium MRI raise concerns. Ultrasound contrast agents are not cleared by the kidney.
- Consider contrast-enhanced ultrasound to characterise an indeterminate renal mass in patients with advanced CKD.
- Use it particularly for complex cystic lesions, where sensitivity was highest, though specificity was lower (80%), so false positives are more likely.
- Discuss findings with urology and radiology; a positive result still needs a management decision.
- Remember that ultrasound contrast agents are not nephrotoxic.
Why it matters
It offers a well-performing kidney-safe option where CT and MRI contrast are a concern.
Don't overread it
Accuracy varied widely between studies and depends on operator experience.
The statistics, in plain English
Sensitivity of 94% means about six in 100 cancers would be missed; specificity of 85% means about 15 in 100 benign masses would look suspicious. High heterogeneity means performance varied a lot between centres and operators.
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