A Novel Nomenclature System for Radiographic Assessment of Pituitary Microadenomas in Cushing's Disease

Introduction: Interpretation of pituitary microadenomas (1 orthogonal plane and >1 sequence), Probable (meets 1 criterion), Possible (tumor visible, but meets neither criterion), and Negative (no tumor visible). Cases were scored first on pituitary protocol (including fat saturation 3mm slices with 0.3mm spacing on T1 pre- and post-contrast, T2 coronal) then after a 4-week washout on skull base protocol (0.8 mm slice with isotropic voxels on T1 pre/post and CISS). Reliability was assessed using intraclass correlation coefficients with a two-way random-effects model. Sample size calculation indicated 34 patients for 80% power. Univariate analysis was performed. Results: A total of 37 cases met the inclusion criteria. [ Fig. 1 ] demonstrates individual radiologist scoring per nomenclature. On the MRI pituitary protocol, across the three raters, the mean scores were 25% (n=9) definitive, 33.3% (n=12) probable. 25% (n=9), and 16.7% (n=6). On MRI skull base protocol, the mean scores were 46.8% (n=17) definitive, 27.9% (n=10) probable. 10.8% (n=4), and 12.6% (n=5). Operative reports documented a tumor in 84.2% (n=32) of patients, pathology reports confirmed a tumor in 68.4% (n=26), and 73.7% (n=28) achieved biochemical remission postoperatively. Inter-rater reliability for the nomenclature was 0.76 using the MRI pituitary protocol and 0.79 using the MRI skull base protocol (p