High-field MRI of the compression of the anterior visual pathway in pituitary adenoma

Non Functional Macro-Adenomas (NFMA) are the most prevalent adenomas of the
pituitary gland. Patients with a NFMA often present with compression on the
anterior optic pathway sometimes combined with pituitary dysfunction. As a
result of the mass effect, the tumour compresses the anterior optic pathway
leading to visual field defects and sometimes decreased vision. Nowadays
(endoscopic) trans-sphenoidal surgery is the first choice primary treatment.
Surgical treatment is often successful in restoring most of the visual field
defects but is less successful in restoring visual acuity. MR-imaging is
currently the main diagnostic tool, conventionally performed with a 1,5 or 3T
(Tesla) MRI.

Primary Objectives:

- Assess the feasibility and clinical value of 7T MR to provide a more detailed
anatomic description of the anterior visual pathway in NFMA patients compared
to conventional MRI.
- Assess the feasibility of high-field MRI to provide pathophysiological
insight of poor visual function in NFMA patients after treatment

Secondary Objective(s):

- Assess the feasibility of high-field MRI to predict the effectiveness of
treatment of NFMA.
- Assess for which of the primary objectives the increased resolution of the
7Tesla is needed or whether a conventional 3Tesla scan would be sufficient.

This study will be a single center, non-blinded study of subjects diagnosed
with a pituitary adenoma. Patients will be scanned at different time points
(pre treatment, 1 week post operatively, 6 months and 12 month time point) to
assess the potential benefit of the 7T MRI over the 3T MRI for disease
progression.

Initially the 7T MRI protocol will be validated to ensure sufficient image
quality for the visualization of the anterior optic pathway, pituitary gland,
pituitary tumor and surrounding tissues. Subsequently NFMA-patients will be
evaluated pretreatment and <1week, 6 and 12 months post-treatment, to correlate
the loss of visual function with the anatomical changes in the optic nerves and
chiasm. The radiological description of the MR-images will be compared with
statistical HFA perimetry, visual acuity, OCT and the Visual Functioning
Questionnaire.

The burden of participation will be a 3T and 7Tesla MRI scans, with contrast
injection, combined with an ophthalmic evaluation at four time points. Most of
these evaluations (the 3T MRI and the ophthalmic evaluations) are already being
performed as part of the standard clinical care, and will therefore not be an
additional burden for the patient.

The risks associated with participation are the potential risks involved with
the high magnetic fields present around an MRI scanner. As all subjects will be
screened for potential contra-indication for MR-scanning, these risks of this
study are effectively removed. There is also a minimal risk associated with the
contrast injection. Patients are screened for any previous contrast reactions.
If previous reactions have occurred then the patient is excluded from the study
to ensure patient safety.