Adrenal Adenomas And Nonadenomas: The Preliminary Study Of The Correlation Between Dynamic Contrast- Enhanced CT And Tumoral Angiogenesis

Objective: To continue to accumulate cases and further to evaluate dynamic contrast-enhanced CT(DCT) of adrenal adenoma and nonadenoma from different sides, and to verify the previous conclusion so that the examination tecnique could be widely applied clinically. Materials and Methods: Seventy-five cases with 85 adrenal masses proven surgically and pathologically and clinically were studied. These masses consisted of 44 adenomas, 35 nonadenomas and 6 hyperplastic nodules (classified as a individual group because of special appearance of DCT). Nonenhanced CT scans were performed in all above-mentioned lesions, followed by DCT with the same parameters (scans beginning at0. 5min,1 min, 2 min, 3 min, 5 min, 7 min after initial injection of contrast material with an injection rate of 2.5ml/s and a dose of1. 2ml/kg). And then, characteristic features of DCT of adrenal masses including time-density curve (T-D curve), peak time(PT), curve slope[(SL, ascending slope(SLa) and descending slope(SLd)), maximum enhancement rate(Emax), washout rate[(Wash, relative washout rate (Washr) and absolute washout rate(Washa)). Results: Type A, B, C, D and E T-D curves were obtained on the basis of the earlier and the later enhancement of T-D curve of DCT of adrenal masses. The curve type was significantly different between adenoma and nonadenoma (P=0. 000). Type A, C belonged to typical curves of adenoma, while type B, D and E belonged to nonadenoma. Significant difference was also present inSLa and SLd and Emax between adenoma and nonadenoma with the exception of PT (P=0. 000). The SLa and Emax of adenoma were higher than those of nonadenoma, but the SLd was lower. Difference of SLa and SLd, Emax in between adenoma and nonadenoma provided theroretically the evidence for the characterization of T-D curve and its clinical application. The sensitivity, specificity and accuracy in diagnosing of adenoma by means of T-D curve were 93%, 80% and 87%, respectively. Moreover, the diagnostic specificity and accuracy were improved to 90% and 92%, if myeolipiomas were not included in the study, since it was most commonly distinguishable. The Washr and Washa of adenoma were both higher than those of nonadenoma; furthermore, the Washr was more efficient than the Washa in differentiation of these lesions. The diagnostic value of both was best at 7min after contrast administration. Washr>34% and Washa>43% were both suggestive of adenoma, vice versa, nonadenoma. Sensitivity, specificity and accuracy in diagnosis of adenoma using Washr and Washa were of 84%, 77% and 81%, respectively; and 84%, 87% and 85% in the absence of myeolipioma in the study. Type A,C; Washr >34% and Washa >43% were typical patterns of DCT of adrenal hyperplastic nodules too. Conclusion: Adrenal adenoma was correctly differentiated from nonadenoma using DCT, which was very valuable especially in differentiation lipid-poor adenoma from nonadenoma. As a result, application of adrenal DCT should be advocated clinically.