Adrenal Washout Calculation

Adrenal SI in-phase:

Spleen SI in-phase:

Adrenal SI out-of-phase:

Spleen SI out-of-phase:

Adrenal-to-spleen CSI ratio:

Adrenal signal intensity index:

In a retrospective study of 42 benign adrenal masses, the CSI ratio had higher specificity than the signal intensity index for lipid-rich adenomas; however, no metastases were included.

Israel GM, korobkin M, Hecht EN et al. Comparison of unenhanced CT and chemical shift MRI in evaluating lipid-rich adrenal adenomas. American Journal of Roentgenology 2004; 183:215-219

In a study of 102 adrenal tumors, all adenomas had signal intensity indexes at least 16.5%, and all metastatic tumors had signal intensity indexes at most 11.2%.

Fujiyoshi F, Nakajo M, Fukukura Y, et al. Characterization of adrenal tumors by chemical shift fast low-angle shot MR imaging: comparison of four methods of quantitative evaluation. American Journal of Roentgenology 2002; 180:1649-1657

Disclaimer: The author makes no claims of the accuracy of the information contained herein; this information is for educational purposes only and is not a substitute for clinical judgment.