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Background
Pituitary adenoma (PA) is one of the most commonly encountered sella lesions in neuroradiology with a reported increasing annual incidence rate. Treatment is determined predominantly by its size (macro/microadenoma) extent, symptomology, and endocrinological function. Surgery is indicated as first-line treatment in patients with visual field deficits or other visual abnormalities, and in functioning PAs, with the exception of prolactinomas, which are treated medically. Large or invasive asymptomatic tumors may be considered for surgery. Although most neuroradiologists are aware of the diagnostic features of PA, there is well-documented variability in reporting styles among radiologists. Furthermore, there is paucity of standardized imaging knowledge of what the surgeons would want to know from imaging in the perioperative period.

Educational Goals / Teaching Points
This clinico-radiological pictorial exhibit will consolidate empirical evidence to familiarize radiologists with preoperative Magnetic Resonance Imaging (MRI) characteristics crucial for pituitary surgery which surgeons would want to see in the report. Immediate and delayed postoperative and post-radiotherapy imaging features would also be covered. A standardized synoptic reporting template of peri-operative PA imaging would also be suggested for neuroradiologists to incorporate into their practice.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
A brief review of standard imaging technique and protocol for preoperative MRI will be reviewed, with attention to the specific diagnostic utility of each sequence. Dynamic contrast-enhanced MRI is the favored modality of choice in assessing PAs. Common artefacts encountered when imaging the sella will be explained. Pertinent anatomical features of the sella barrier and type, inter-carotid distance, native sphenoid sinus anatomy and pneumatization pattern, location of native pituitary gland and posterior bright spot are crucial presurgical determinants. Tumor characteristics such as vascularity, consistency, optic apparatus compression and grade/severity of cavernous sinus invasion also have significant postoperative prognostic ramifications. Specific MRI characteristics may also have a role in predicting postoperative outcomes. Postoperative imaging continues to be a diagnostic challenge and imaging pearls to distinguish early and late postsurgical changes from residual disease, assessment of completeness of resection and associated complications will be discussed.

Conclusion
Neuroradiologists should be armed with essential prerequisite knowledge when reporting PA in the perioperative course. This will aid surgeons and endocrinologists with management decisions, planning and execution of pituitary surgery and appropriate postoperative follow up.