Complex cystic renal masses: characterization with contrast-enhanced US.
OBJECTIVE
To prospectively compare contrast material-enhanced ultrasonography (US) with computed tomography (CT) in the classification of complex cystic renal masses with the Bosniak system.


METHODS
Ethics committee approval and written informed consent were obtained. Forty patients (17 women, 23 men; age range, 31-77 years) with 44 complex cystic renal masses detected with conventional US were prospectively examined by using second-harmonic US with a second-generation contrast agent and multiphasic helical CT. Thirty-six patients had one lesion, and four patients had two lesions. Surgical resection in nine patients and imaging follow-up in 31 patients were used to determine the outcome.


RESULTS
On contrast-enhanced US images, masses were classified as Bosniak category II (n = 18), IIF (ie, lesions were classified as category II and follow-up was needed) (n = 16), III (n = 7), or IV (n = 3) lesions. On CT images, masses were classified as Bosniak category II (n = 24), IIF (n = 10), III (n = 7), or IV (n = 3) lesions. Interobserver agreement was high (kappa = 0.86, P < .001) for classification with US. Complete concordance between the readers was found for classification with CT. Complete concordance between contrast-enhanced US and CT was observed in the differentiation of surgical and nonsurgical complex cysts. Complete concordance among the three readers in the assessment of vascularity with contrast-enhanced US was found. Interobserver agreement in the evaluation of enhancement on CT images was high (kappa = 0.88, P < .001). Concordance between contrast-enhanced US and CT in the evaluation of vascularization was high (kappa = 0.77, P < .001).


CONCLUSIONS
The study data suggest that contrast-enhanced second-harmonic US is appropriate for renal cyst classification with the Bosniak system.
Ascenti
Giorgio
G
Department of Radiological Sciences, University of Messina, via Consolare Valeria-Gazzi, 98100 Messina, Italy.
Mazziotti
Silvio
S
Zimbaro
Giovanni
G
Settineri
Nicola
N
Magno
Carlo
C
Melloni
Darwin
D
Caruso
Rosario
R
Scribano
Emanuele
E
D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging; D003287:Contrast Media; D003560:Cysts / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000000981:diagnostic imaging*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000379:methods
D003287:Contrast Media