Investigation of Cushing's and subclinical Cushing's syndromes using adrenocortical scintigraphy

This study assessed the factors related to the intake rate of adrenocortical scintigraphy in Cushing's and subclinical Cushing's syndromes, in addition to the methods for differentiating between the two.

Clinical findings, blood sampling, and adrenocortical scintigraphy collected at St. Marianna University School of Medicine from 1 January 2010 to 31 December 2019 were used to diagnose initial-onset Cushing's syndrome and subclinical Cushing's syndrome, and patients who underwent 131I-NP-59 adrenocortical scintigraphy were used as study subjects.

A total of 24 (8 male and 16 female) patients were selected. Of them, 7 had Cushing's syndrome and 17 had subclinical Cushing's syndrome. A correlation coefficient of -0.474 (P = 0.026) was determined between the intake rate after 7 days and adrenocorticotropic hormone levels. Intake rates after 5 days were 0.51% and 0.31% for Cushing's and subclinical Cushing's syndromes, respectively, and were statistically significant (P = 0.03). Intake rates after 7 days were 0.47% and 0.30% for Cushing's and subclinical Cushing's syndromes, respectively, and were statistically significant (P = 0.04). Receiver operating characteristic analysis results of Cushing's and subclinical Cushing's syndromes for intake rates after 7 days were as follows: cutoff value, 0.248; area under curve, 0.769; and 95% confidence interval, 0.561-0.977.

There were differences in the intake rates of adrenocortical scintigraphy between the Cushing's syndrome group and subclinical Cushing's syndrome group, making it possible to differentiate between the two using the intake rate.