MR Elastography of Pituitary Macroadenomas with Intraoperative and Immunofluorescence correlation: A Feasibility study along with Literature Review.

Background: Pituitary adenomas (PA) are a prevalent type of intracranial space-occupying lesions (SOLs). Most pituitary tumours exhibit soft consistency, and some of them show firm or hard characteristics. Therefore, it is important to discern the preoperative consistency of these tumours to select appropriate surgical interventions to reduce the likelihood of residual or recurrent disease. Magnetic resonance elastography (MRE) presents a promising novel technique for assessing the preoperative consistency of adenomas. This study investigated MRE's potential utility in determining preoperative tumour consistency in PAs.

Method: This prospective study included cases of pituitary macroadenomas (PMA) (size > 2 cm). Preoperative measurements of tumour stiffness using MRE were conducted. Neurosurgeons were blindfolded to radiological MRE tumour consistency and graded tumour consistency during surgery that was documented in operative notes. A correlation between the preoperative MRE tumour consistency to surgical consistency and collagen I & III values on immunofluorescence was done.

Results: Nine patients were included in the study, with a mean age of 52±9.6 years. Eight of the nine patients underwent Endoscopic Trans-Nasal Trans-Sphenoidal (TNTS) surgery, and one underwent craniotomy. Based on surgical tumour consistency, six patients were categorized as soft, and three as firm. The mean MRE value was 1.99±0.53 (1.33-3.23) kPa. A Comparison between surgical tumour consistency and MRE showed moderate agreement with a Cohen's Kappa value of 0.769. The comparison of MRE values with collagen I showed a weak positive correlation (Pearson correlation value = 0.417), while the correlation with collagen III demonstrated a positive correlation (Pearson correlation value = 0.556).

Conclusion: MRE can help in the pre-operative prediction of the consistency of the pituitary macroadenomas with a moderate degree of agreement between pre-operative MRE and operative characterization of tumour consistency by the surgeons.