Improved noninvasive diagnostic evaluations in treatment-naïve adrenocorticotropic hormone (ACTH)-dependent Cushing's...

Bilateral inferior petrosal sinus sampling (BIPSS) is important in the differential diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome, but BIPSS is invasive and is not reliable on tumor lateralization. Thus, we evaluated the noninvasive diagnostic evaluations, high-dose dexamethasone suppression test (HDDST) combined with different pituitary MRI scans (conventional contrast-enhanced MRI [cMRI], dynamic contrast-enhanced MRI [dMRI], and high-resolution contrast-enhanced MRI [hrMRI]), by comparison with BIPSS.

We retrospectively analyzed 95 patients with ACTH-dependent Cushing's syndrome who underwent HDDST, preoperative MRI scans (cMRI, dMRI and hrMRI) and BIPSS in our hospital between January 2016 and December 2021. The diagnostic performance of HDDST combined with cMRI (HDDST + cMRI), HDDST + dMRI and HDDST + hrMRI, and BIPSS was evaluated, including the sensitivity of identifying pituitary adenomas and the tumor lateralization accuracy.

Compared with BIPSS (AUC, 0.98; 95%CI: 0.93, 1.00), the diagnostic performance of HDDST + hrMRI was comparable in both neuroradiologist 1 (AUC, 0.95; 95%CI: 0.89, 0.99; P = 0.129) and neuroradiologist 2 (AUC, 0.98; 95%CI: 0.92, 1.00; P = 0.707). For tumor lateralization accuracy, HDDST + hrMRI (90.6-95.3%) were significantly higher than that of BIPSS (24.7%, P < 0.001).

In patients with ACTH-dependent Cushing's syndrome, HDDST + hrMRI, as noninvasive diagnostic evaluations, achieves high diagnostic performance comparable with gold standard (BIPSS), and it is superior to BIPSS in terms of tumor lateralization accuracy.