The Evaluation Of Dynamic Enhanced CT In Differentiating Adrenal Adenomas From Non-Adenomas

Objective: TO evaluate dynamic enhanced CT in differentiating adrenal adenomas from non-adenomas,to determine the optimal scanning parameters and to establish the differentiation criteria.Methods:Forty-one patients with 43 adrenal tumors(22 adenomas and 21 non-adenomas) were enrolled into this study,.Nonenhanced CT was followed by dynamic contrast-enhanced CT at 1min,3min,5 min and 7 min later . 35 tumors were proved by surgically and pathologically and 6 cases with 8 metastases were proved by the dynamic observation in three months.The CT attenuation value was measured in all tumors at different scanning time and acquired the time-density(T-D) curves.The type of A and C belong to the Group faster Wash and the type of B,D,E belong to the Group slower Wash.The absolute washout percentage(Washa) and relative washout percentage(Washr) at different time were measured and identify the best delayed time and the washout percentage to distinguish adenomas from non-adenomas by ROC curve.The data were analyzed with T-test and X- test by SPSS12.0 statistical software,and P<0.05 was considered to be significant.Results:The types of T-D curves have significant differences between adenomas and non-adenomas.The adenomas appeared with the type of A and C.The non-adenomas appeared with the type of B,C,E. 5min-delayed wash percentage have significant differences between adenomas and non-adenomas .Washr≥32% or Washa≥26% wasthe cue to adenomas,otherwise was non-adenomas.The standard based on both the T-D curves and the 5min-delayed washout percentage improved the sensitivity,specificity and accuracy to adenomas ,which were 96%,95%,95%。Conclusion:Both T-D curve and Washr≥32% or Washa≥26% at 5min-delayed CT were helpful in differentiating adrenal adenomas from non-adenomas.The standard based on both two can improved the value in differentiating adrenal adenomas from non-adenomas.