Postoperative DWI morphology and neurological worsening after eloquent-area glioma surgery: a retrospective cohort study.

PURPOSE: To assess whether the association between postoperative diffusion-weighted imaging (DWI) and neurological worsening after eloquent-area glioma surgery differs according to lesion morphology.

METHODS

We retrospectively analyzed 139 consecutive patients undergoing resection of eloquent-area supratentorial gliomas (WHO 2-4). Postoperative MRI (< 48 h) classified lesions as sector- or rim-shaped. Neurological status was assessed at discharge and 4-6 months.

RESULTS

DWI lesions occurred in 44/139 patients (31.7%; 31 sector-shaped, 13 rim-shaped); 59 (42.4%) worsened at discharge. Overall, DWI positivity alone was not associated with worsening. Sector-shaped DWI lesions were associated with neurological worsening (positive predictive value, PPV of 58.1%) and remained associated after multivariable adjustment (OR 3.83, 95% CI 1.30-11.29), although the confidence interval was wide and the unadjusted association was borderline. Rim-shaped lesions carried a PPV of 38.5%, comparable to the risk in DWI-negative patients (37.9%), and the two morphologies did not differ significantly in direct comparison. Awake craniotomy was also independently associated with worsening, and frontal site with a lower risk. 61% of worsening occurred with negative DWI. A deficit was present at the 4-6 month follow-up in 9 patients (6.5%), all with IDH-wildtype glioblastoma, and was associated with a ≥ 50% evoked-potential decrease.

CONCLUSION

In this cohort, postoperative DWI positivity was associated with neurological worsening mainly when the lesion was sector-shaped, a finding that requires confirmation in larger series. Rim-shaped lesions showed a risk of worsening similar to that of a negative scan. Most worsening occurs without DWI ischemia, suggesting non-ischemic mechanisms of function-guided surgery. A deficit at follow-up occurred only in IDH-wildtype glioblastoma and was associated with intraoperative neurophysiological changes.