Determining Surgical Resection and Recurrence in NFPAs

The extent of surgical resection was determined by review of postoperative MRI by a neuroradiologist (C-CK) and a neurosurgeon (S-WL). According to published literature (25 (link)), GTR was defined as lesion resection with a residual tumor volume of less than 10% of its original size. In contrast, subtotal tumor resection (STR) was defined as the presence of residual lesion more than 10% of its original volume. For determining P/R in NFPAs, pretreatment and postoperative MR images were evaluated by two experienced neuroradiologists (C-CK with 6 years of experience and T-YC with 18 years of experience), both of whom were blinded to the clinical and imaging outcomes of the studied population. P/R was defined as tumor recurrence after GTR or enlargement of residual tumor after STR observed on postoperative contrast-enhanced (CE) T1WI. The threshold of P/R was defined as a more than 2-mm increase in size of residual tumor in at least one dimension when compared with postoperative MRI studies (11 (link), 26 (link)). Inter-observer reliability in the determination of P/R was obtained via a Cohen k value of 0.9. In equivocal cases, judgment was made via consensus. On preoperative MR images, cavernous sinus invasion (Knosp classification) (27 (link)) and extrasellar extension (Hardy’s classification) (28 ) were determined on coronal T2WI and CE T1WI.