Pituitary gland MRI and Cushing disease: about 14 operated patients

Purpose. Evaluate the MR sensibility for detection and localisation of ACTH-secreting microadenomas of the pituitary gland. Patients and method. The MRI studies of the pituitary gland, performed before transsphenoidal surgical exploration, about 14 patients who present clinical and biological signs of Cushing disease, were reviewed retrospectively. We have always used unenhanced sagittal and coronal spin-echo T1 sequences, and coronal T1 after injection of gadolinium (1 Tesla). Results. The global sensibility for detection of an adenoma was 100% (84 to 92% when the lesional localisation was considered). The injection of gadolinium increased the sensibility of 38 to 42% according the readers. 7 to 14% of the lesions were isointense after injection. The estimation of lesional size after injection was the nearer to the surgical results. The indirect sign most frequently seen (35.7 to 64.3%) was focal bulging of the sellar diaphragm. The only differences between the different radiologists, statistically significant, concerned the lesional size before injection and location of the lesion in the sagittal plane. Conclusion. This study confirmed the good sensibility of contrast-enhanced MRI in detection of ACTH-secreting microadenomas. The anatomo-radiological correlations are nevertheless incomplete.