MRI for Cushing Disease: A Systematic Review.

Background: MR imaging is key in the diagnostic work-up of Cushing disease. The sensitivity of MR imaging in Cushing disease is not known nor is the prognostic significance of "MR imaging-negative" disease.

Purpose: Our aim was to determine the overall sensitivity and prognostic significance of MR imaging localization of Cushing disease.

Data Sources: We performed a systematic review of the MEDLINE and PubMed databases for cohort studies reporting the sensitivity of MR imaging for the detection of adenomas in Cushing disease.

Study Selection: This study included 57 studies, comprising 5651 patients.

Data Analysis: Risk of bias was assessed using the methodological index for non-randomized studies criteria. Meta-analysis of proportions and pooled subgroup analysis were performed.

Data Synthesis: Overall sensitivity was 73.4% (95% CI, 68.8%-77.7%), and the sensitivity for microadenomas was 70.6% (66.2%-74.6%). There was a trend toward greater sensitivity in more recent studies and with the use of higher-field-strength scanners. Thinner-section acquisitions and gadolinium-enhanced imaging, particularly dynamic sequences, also increased the sensitivity. The use of FLAIR and newer 3D spoiled gradient-echo and FSE sequences, such as spoiled gradient-echo sequences and sampling perfection with application-optimized contrasts by using different flip angle evolutions, may further increase the sensitivity but appear complementary to standard 2D spin-echo sequences. MR imaging detection conferred a 2.63-fold (95% CI, 2.06-3.35-fold) increase in remission for microadenomas compared with MR imaging-negative Cushing disease.

Limitations: Pooled analysis is limited by heterogeneity among studies. We could not account for variation in image interpretation and tumor characteristics.

Conclusions: Detection on MR imaging improves the chances of curative resection of adenomas in Cushing disease. The evolution of MR imaging technology has improved the sensitivity for adenoma detection. Given the prognostic importance of MR imaging localization, further effort should be made to improve MR imaging protocols for Cushing disease.