Three-Dimensional Fast Spin Echo Pituitary MRI in Treatment-Naïve Cushing's Disease: Reduced Impact of Reader Experience and Increased Diagnostic Accuracy

Background: In patients with Cushing's disease, the preoperative identification of pituitary adenomas is crucial to treatment. However, increasing diagnostic accuracy remains an unresolved issue.

Purpose: To evaluate the diagnostic accuracy and the impact of readers' experience regarding high-resolution contrast-enhanced magnetic resonance imaging (hrMRI) for identifying pituitary adenomas in comparison with conventional contrast-enhanced MRI (cMRI) and dynamic contrast-enhanced MRI (dMRI).

Study type: Retrospective.

Population: Sixty-five patients (median age, 39 years; interquartile range [IQR], 28-53 years; 60% females) with treatment-naïve Cushing's disease.

Field strength/sequence: 3-T, seven fast spin echo sequences.

Assessment: The diagnostic accuracies of identifying pituitary adenomas on cMRI, dMRI, combined cMRI and dMRI (cdMRI), and hrMRI were independently evaluated by six readers with three experience levels (high: >20 years, modest: 10-20 years, low: <10 years; two readers for each experience level). Readers were asked to localize the lesion, and measure its diameter on the sequence where identified. The reference standard was postoperative histopathology. The impact of readers' experience and interobserver agreement were assessed. Image quality was assessed using a 5-point Likert scale, including overall image quality, sharpness, and structural conspicuity.

Statistical tests: McNemar's test, Cochran's test, Wilcoxon signed-rank test, Mann-Whitney U test, and κ statistics for interobserver agreement. A P-value <0.05 was considered statistically significant.

Results: For identifying pituitary adenomas (median diameter, 5 mm; IQR, 4-5 mm), hrMRI had significantly higher sensitivity (87.7%-93.8%) than cMRI, dMRI, and cdMRI (52.3%-75.4%) for readers with different experience levels. The interobserver agreement was moderate (κ = 0.461-0.523). The sensitivity for hrMRI was comparable between readers with different experience levels (P = 0.371). All image quality scores on hrMRI were significantly higher than cMRI and dMRI (5.0 vs. 4.0).

Data conclusion: For identifying pituitary adenomas in patients with treatment-naïve Cushing's disease, hrMRI may show high diagnostic accuracy and seems not to be affected by readers' experience.

Level of evidence: 3 TECHNICAL EFFICACY: Stage 2.