Adrenal Characterization

9% of population have adrenal adenomas
adrenal also common site of metastases, particularly lung carcinoma

The following evaluation is derived from Caoili et al. Enter the HU from the adrenal mass into the calculator. Adrenal adenomas have two properties that can be used to distinguish them from nonadenomas.

1. Adenomas contain lipid and will be of low attenuation at unenhanced CT.
2. Adenomas rapidly washout contrast material

  
Technique  
Injection 150 ml contrast at 2 ml/sec
Initial Enhanced attenuation measured at 60 sec
Delayed attenuation measured at 15 minutes
Measure ROI at least 1/2 size of mass
  Sensitivity Specificity Likelihood ratio + test Likelihood ratio - test
% Relative Washout (adenomas > 40%) 82 (59-96) 92 (79-98) 11 (4-32) 0.2 (0.08-0.48)
% Enhancement Washout (adenomas > 60%) 86 (65-98) 92 (79-98) 11 (4-34) 0.15 (0.05-1.4)
n = 166 patients (adenoma 127, nonadenoma 39) (from Caoili et al)
References
Dunnick NR,Korobkin M. Imaging of adrenal incidentalomas: current status. AJR 2002; 179:559-68. [Related Records]

Caoili EM, Korobkin M, Francis IR, et al. Adrenal masses: characterization with combined unenhanced and delayed enhanced CT. Radiology 2002; 222:629-33. [Related Records]

Nwariaku FE, Champine J, Kim LT, et al. Radiologic characterization of adrenal masses: the role of computed tomography--derived attenuation values. Surgery 2001; 130:1068-1071. [Related Records]

Pena CS, Boland GW, Hahn PF, Lee MJ, Mueller PR. Characterization of indeterminate (lipid-poor) adrenal masses: use of washout characteristics at contrast-enhanced CT. Radiology 2000; 217:798-802. [Related Records]

Caoili EM, Korobkin M, Francis IR, Cohan RH,Dunnick NR. Delayed enhanced CT of lipid-poor adrenal adenomas. AJR 2000; 175:1411-5. [Related Records]

Szolar DH, Kammerhuber FH. Adrenal adenomas and nonadenomas: assessment of washout at delayed contrast-enhanced CT. Radiology 1998; 207:369-75. [Related Records]

Szolar DH, Kammerhuber F. Quantitative CT evaluation of adrenal gland masses: a step forward in the differentiation between adenomas and nonadenomas? Radiology 1997; 202:517-521. [Related Records]

Korobkin M, Brodeur FJ, Yutzy GG, et al. Differentiation of adrenal adenomas from nonadenomas using CT attenuation values. AJR 1996; 166:531-536. [Related Records]

Resources: Management of the clinically inapparent Adrenal Mass "Incidentaloma" NIH State-of-the-Science Conference Feb 4-6, 2002.

Disclaimer: Information provided is not intended to be medical or technical advice. The information given at this site is for educational purposes only and is not sufficient for medical decisions. I disclaim any liability for the acts of any physicians or any other individual who receives any information on any medical procedure through this web site. I accept no legal responsibility for any injury and/or damage to persons or property from any of the suggestions or material discussed herein.