Aydın Talat BAYDAR, Muhammed BAYINDIR
Journal of Turkish Spinal Surgery - 2026;37(4):134-141
Objective: Postoperative magnetic resonance imaging (MRI) is important after intradural spinal tumor surgery, but the optimal timing of early postoperative imaging is not standardized. This study compared postoperative day 1 (POD1) MRI with delayed early MRI in detecting residual tumor. Materials and Methods: This retrospective single center cohort included patients who underwent surgery for intradural spinal tumors between June 2020 and December 2025. Patients who underwent gadolinium-enhanced POD1 MRI and delayed early gadolinium-enhanced MRI (performed within POD30-60) were analyzed. Patient-level timing of delayed early MRI was recorded. Two blinded, spine-focused neurosurgeons reviewed MRI studies using predefined criteria. Results: Ninety-six patients from a 112-patient intradural spinal tumor cohort had paired imaging. Sixteen patients were excluded because of missing MRI studies. A delayed early MRI was obtained a median of 48 days after surgery (interquartile range, 41-56; range, 33-60). POD1 and delayed early MRI were concordant with respect to the presence of residual tumor in 95 of 96 patients. With delayed early MRI as the paired imaging comparator, POD1 MRI demonstrated 93.3% sensitivity, 100.0% specificity, 98.8% negative predictive value, 99.0% accuracy, and a kappa coefficient of 0.959. Progression occurred in 7 of 13 patients (53.8%) with POD1 residual tumor and in 1 of 81 patients (1.2%) without POD1 residual tumor (p<0.001). Conclusion: POD1 gadolinium-enhanced MRI showed very high agreement with delayed early MRI in detecting residual tumor after intradural spinal tumor surgery and may serve as a reliable early baseline for residual tumor assessment. However, cerebrospinal fluid (CSF) collection and T2 signal change were more time-dependent findings, supporting selective delayed imaging when early findings are equivocal or postoperative symptoms or CSF-related concerns persist.
