Background: Endoscopic endonasal transsphenoidal surgery is a minimally-invasive technique that is suitable for treatment of most pituitary macroadenomas, which can be easily and effectively removed using a combination of endoscopic techniques such as suction, cauterization, and curettage. However, some pituitary macroadenomas are not easy to remove via the endoscopic approach, if they are firm, highly vascularized, or fibrous in consistency. In such cases, further transcranial surgery either by keyhole supraorbital or conventional craniotomy may be needed.

Objective: To assess the benefits of conventional magnetic resonance imaging (MRI) techniques in predicting outcomes of endoscopic surgery.

Materials and Methods: Thirty-nine cases of pituitary macroadenomas with preoperative conventional MRI sequences (T1W, T2W, T1W+Gd, and FLAIR) were included in the present study. The authors compared the difference in signal intensity (SI) between the tumor area and pons. All operations were performed using standard endoscopic transsphenoidal techniques in combination with neuro-navigators. All operations were performed by the same team of neurosurgeon and otolaryngologist. The outcomes were categorized into three groups, “Satisfactory”, “Fair”, and “Unsatisfactory”, according to the amount of tumor left after the operations. Finally, statistical tests with binary logistic regression model, ROC, and AUC were used to study the relationship between the four MRI sequences and the outcomes of the operations.

Results: The present study included 39 cases of pituitary macroadenomas. The tumor to pons SI ratios of T2W sequence were significant indicators of the probability of success with endoscopic surgery. The ROC analysis suggested that the cutoff point should be set at a T2W ratio of less than 1.971 for female patients and 1.515 for males. The sensitivity, specificity, and accuracy were 92.31%, 73.08%, and 79.49%, respectively.

Conclusion: Scrutiny of preoperative MRI analysis using SI ratio (macroadenomas versus pons) in T2W MRI is useful in predicting the success of the endoscopic endonasal transsphenoidal approach in removal of pituitary macroadenomas.

Keywords: Pituitary macroadenoma, Endoscope, Transsphenoid, MRI, Outcome, Prediction, Selection

Received 2 Aug 2019 | Revised 29 Oct 2019 | Accepted 8 Nov 2019