Pituitary Adenoma Imaging as a Determinant of Acromegaly Diagnosis and Outcomes

In the majority (> 95%) of patients with acromegaly, the underlying cause is a somatotroph adenoma. Pituitary-targeted surgery and radiotherapy can achieve long-term disease control but carry a significant adverse risk to the remaining normal gland, especially if undertaken outside a Pituitary Tumor Center of Excellence or when repeat surgery is performed. Maximizing benefits and minimizing risks of pituitary surgery and radiotherapy is critically dependent on high-quality imaging that allows accurate localization of site(s) of either de novo, residual or recurrent disease. Macroadenomas continue to predominate among somatotroph tumors (70%), but more widespread use of intracranial imaging is leading to the earlier detection of smaller adenomas, which pose new challenges for imaging diagnostics. Despite several comprehensive guidelines on the management of acromegaly, there is little consensus regarding optimal imaging and current scanning protocols remain heterogeneous. This serves as a barrier to optimal patient management and constrains comparison between centers, with inevitable consequences for research within the field. Here, based on a comprehensive review of previous studies and focusing on recent advances in magnetic resonance and molecular (functional) imaging techniques, we propose a standardized, tiered approach to pituitary imaging in patients with acromegaly, guided by individual patient features and tailored to the anticipated therapeutic approach. An online tool, which can be adapted to the clinical context, is provided as an aid to decision-making.