2026 Poster Presentations
P045: QUANTITATIVE MRI ASSESSMENT OF PARENCHYMAL INJURY FOLLOWING TRANSCALLOSAL AND ENDOSCOPIC APPROACHES TO THIRD VENTRICLE COLLOID CYSTS
Ufuk Erginoglu, MD; Umid Sulaimanov, MD; Yerkebulan Serikkanov, MD; Abdullah Keles, MD; Mustafa K Baskaya, MD; University of Wisconsin - Madison
Background: Third ventricle colloid cysts (TVCCs) can result in obstructive hydrocephalus and acute neurological deterioration. Both the interhemispheric transcallosal approach (ITA) and endoscopic approach (EA) are established treatment strategies; however, their relative parenchymal impact on postoperative MRI, and the evolution of early to late imaging changes, remain poorly characterized.
Objective: To compare early volumetric MRI findings following ITA and EA for TVCC resection and to determine whether early parenchymal injury persists on late imaging.
Methods: A retrospective review was conducted of 23 patients (ITA, 13; EA, 10) who underwent both early and late postoperative MRI. Early T2/FLAIR hyperintensity volumes were segmented along the surgical tract; in EA cases, burr-hole tract volume was subtracted. Diffusion restriction was assessed with DWI/ADC. Late MRI was examined for gliosis, encephalomalacia, and parenchymal loss. Statistical analyses evaluated differences between approaches and correlations between early volumes and late outcomes.
Results: Early hyperintensity volumes were significantly smaller after ITA compared with EA (349 ± 218 mm³ vs. 2952 ± 2084 mm³; p < 0.001). Diffusion restriction was observed in 7.7% of ITA versus 50% of EA cases (p = 0.052). On late MRI, gliosis, encephalomalacia, and parenchymal loss were absent in ITA but present in 50% of EA cases (p = 0.007 each). In EA, larger early volumes correlated with gliosis (p = 0.032), encephalomalacia, and parenchymal loss (p = 0.016 each). Gross total resection was achieved in 92% of ITA versus 50% of EA cases (p = 0.039).
Conclusion: Compared with ITA, EA was associated with larger early parenchymal injury, half of which persisted as structural abnormalities on late imaging, indicating an increased risk of lasting tissue damage.