Complex cystic renal masses: characterization with contrast-enhanced US

Area of Science:

• Radiology
• Medical Imaging
• Urology

Background:

• Accurate classification of complex cystic renal masses is crucial for patient management.
• The Bosniak classification system is the standard for categorizing these lesions.
• Computed tomography (CT) is commonly used, but contrast-enhanced ultrasonography (CEUS) offers an alternative.

Purpose of the Study:

• To prospectively compare contrast-enhanced ultrasonography (CEUS) with computed tomography (CT) for classifying complex cystic renal masses.
• To evaluate the performance of CEUS using the Bosniak system.
• To assess interobserver agreement and concordance between CEUS and CT.

Main Methods:

• Forty patients with 44 complex cystic renal masses underwent both second-harmonic CEUS with a contrast agent and multiphasic helical CT.
• Masses were classified according to the Bosniak system by both imaging modalities.
• Surgical resection or imaging follow-up was used to determine the outcome.

Main Results:

• CEUS classified masses as Bosniak categories II (n=18), IIF (n=16), III (n=7), and IV (n=3).
• CT classified masses as categories II (n=24), IIF (n=10), III (n=7), and IV (n=3).
• High interobserver agreement was observed for CEUS (kappa=0.86) and CT (kappa=0.88). Concordance between CEUS and CT for differentiating surgical/nonsurgical cysts was complete, and for vascularity assessment was high (kappa=0.77).

Conclusions:

• Contrast-enhanced second-harmonic ultrasonography is appropriate for renal cyst classification using the Bosniak system.
• CEUS demonstrates high concordance with CT in evaluating complex cystic renal masses.
• CEUS is a valuable tool for differentiating surgical from nonsurgical renal cysts.