Adrenal MRI Calculator
CSI ratio:
lesion SIOP/spleen SIOP
lesion SIIP/spleen SIIP
SI index:
lesion SIIP-lesion SIOP
lesion SIIP
x 100
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. Am J Roentgenol 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. Am J Roentgenol 2002; 180:1649-1657
One study showed MRI to be equivalent to CT for characterizing adenomas measuring 20 HU or less. However, MRI is less sensitive than CT for lipid-poor adenomas measuring more than 20 HU.
Seo JM, Park BK, Park SY, Kim CK. Characterization of lipid-poor adrenal adenoma: chemical-shift MRI and washout CT. Am J Roentgenol 2014; 202:1043-50
Schieda N, Siegelman E. Update on CT and MRI of adrenal nodules. AJR Am J Roentgenol 2017; 208:1-12