Review of 7T MRI imaging of pituitary microadenomas: are we there yet?

7T MRI imaging of the pituitary gland is an emerging technique. The purpose of this article is to review the current status of the 7T MRI of the pituitary gland, particularly in the context of pituitary microadenoma pathology. We will discuss technical challenges and parallel transmission opportunities.

Follow-up study selection and data extraction were performed following PRISMA guidelines. We focused on diagnostic performance and acquisition protocols. Inclusion criteria were: MRI imaging studies of pituitary adenoma at 7T. Exclusion criteria were: Case reports and reviews; studies which did not report MRI protocols; surgical planning studies; studies focusing exclusively on macroadenomas for which ultra-high magnetic field imaging is less decisive than microadenomas in clinical practice.

Six studies were included. 7T MRI outperformed 1.5 or 3T MRI for the detection of microadenomas. Acquisition protocols employed were heterogeneous, with two-dimensional T_2-w and T_1-w turbo spin-echo sequences, three-dimensional T_1-w isotropic spin-echo and gradient-echo sequences (resolution: 0.6 and 0.8 mm), and dynamic contrast-enhanced T_1-w sequences.

7T MRI is a promising tool for overcoming the difficulties encountered by conventional MRI, particularly in the case of Cushing disease. However, there is insufficient data to precisely define an optimal protocol yet.