Objective: In Cushing's disease (CD), detection of an adenoma by MRI is challenging. The aim of this study is to compare real-life MRI in the initial diagnostic workup of CD with high-quality MRI performed in a tertiary center for pituitary diseases.
Design and methods: We retrospectively analyzed 139 patients with CD who underwent primary transsphenoidal surgery (TSS) in our department and had both an MRI conducted at a different institution (external MRI; extMRI) and an MRI conducted at our institution (internal MRI; intMRI). Preoperative interpretation of MRI was performed independently by an external radiologist (extRAD), an internal neuroradiologist (intRAD) and a pituitary surgeon (SURG). Intraoperative detection of an adenoma and endocrinological remission provided proof of the true adenoma localization in 105 patients.
Results: Interpretation of extMRI by extRAD and SURG was concordant in only 64% (89/139) of cases, while 74.1% (103/139) concordance was observed for interpretation of intMRI by intRAD and SURG. Based on extMRI, the true localization of the adenoma was correctly predicted in only 46.7% of the patients by extRAD and in 65.7% by SURG. In contrast, the sensitivity to correctly identify the adenoma on intMRI was 80.0% for intRAD and 94.3% for SURG.
Conclusion: Both the quality of MRI and the reader's experience are paramount for detection of microadenomas in CD. Every effort should be made to perform high-quality initial MRI according to current standards and to ensure rating by an expert in pituitary imaging.