Liu Y, Kan Y, Zhang J, et al. - For diagnosing solid clear cell renal cell carcinoma (sccRCC) ≤4 cm using contrast-enhanced ultrasound (CEUS), hyperenhancement, fast-in contrast agent, and heterogeneous enhancement may be helpful characteristics, while the presence of a pseudocapsule and fast-out of contrast agent could have low diagnostic values. Improved diagnostic value may be achieved with the combination of multiple indexes.

• This meta-analysis included 10 studies to evaluate the ability of CEUS to diagnose solid ccRCC (sccRCC) ≤4 cm.

• For diagnosing sccRCC ≤4 cm, medium sensitivity (67%–89%) and specificity (42%–75%) were demonstrated by hyperenhancement.

• High diagnostic abilities (area under curve (AUC) 0.74–0.84) were demonstrated by fast-in contrast agent and heterogeneous enhancement, however, the presence of a pseudocapsule and fast-out contrast agent had poor diagnostic ability (AUC <0.70).

• A high sensitivity (98%) for diagnosing sccRCC ≤4 cm was afforded by the combination of hyperenhancement and iso-enhancement.