Three-phase, contrast-enhanced, multidetector CT in the evaluation of complicated renal cysts: comparison of the postcontrast phase combination.
BACKGROUND
Multiphasic multidetector computed tomography (MDCT) is widely used for the assessment and diagnosis of complicated renal cysts.


OBJECTIVE
To determine the optimal combination of postcontrast phases of MDCT for the evaluation of complicated renal cysts.


METHODS
In 164 renal cysts with pathology confirmation or follow-up >2 years, the Bosniak category was recorded by two radiologists in consensus. They reviewed the MDCT images during three interpretation sessions. In the first session, the radiologists evaluated two phases of images (unenhanced and corticomedullary phases), while during the second session, they evaluated two phases of images (unenhanced and parenchymal phases), and in the third session, they evaluated all three phases of images (unenhanced, corticomedullary, and parenchymal phases). The diagnostic accuracy for evaluating renal cysts was compared in each session using receiver-operating characteristics (ROC) analysis.


RESULTS
There were 106 benign renal cysts and 58 malignant renal cysts. The areas under the ROC curves (AUCs) of the second and third sessions were greater than that of the first session (P < 0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of the first session were 74%, 88%, 77%, and 86%, respectively, and those of the second session were 90%, 85%, 77%, and 94%, respectively. The values of the third session were identical to those of the second session.


CONCLUSIONS
Unenhanced and parenchymal phase CT scans are sufficient for differentiating malignant from benign renal cysts and there was no additional value by adding the corticomedullary phase to the combination of unenhanced and parenchymal phase CT.
Department of Radiology, Research Institute of Radiology Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Mi-Hyun
MH
Kim
Rang
R
Yi
Kyoung-Sik
KS
Cho
Hyuck Jae
HJ
Choi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D003287:Contrast Media
CT; Urinary; adults; cysts; kidney