Intratumoral susceptibility signals on susceptibility-weighted imaging for glioma grading and molecular profiling: a systematic review and meta-analysis.

Background

Intratumoral susceptibility signals on susceptibility-weighted imaging have emerged as a potential biomarker for glioma grading and molecular characterization.

Purpose

To evaluate the diagnostic performance of intratumoral susceptibility signals for glioma grading using harmonized World Health Organization grade contrasts. DATA SOURCES PubMed, Embase, and Cochrane were searched from inception through December 18, 2025. STUDY SELECTION Studies reporting preoperative semiquantitative assessment of intratumoral susceptibility signals in histologically confirmed gliomas were included; grading reference standards ranged from histology-based to integrated 2021 World Health Organization histomolecular diagnosis. DATA ANALYSIS The primary analysis compared World Health Organization grades III-IV with grade II. Alternative contrasts were analyzed separately. Threshold-specific sensitivity and specificity were pooled when at least 3 comparable studies were available. Observed-only and leave-one-out analyses assessed robustness. DATA SYNTHESIS Nineteen studies including 1383 patients were included; 10 contributed to quantitative grading analyses. For World Health Organization grade III-IV versus II, pooled sensitivity and specificity were 0.96 (95% CI, 0.86-0.99) and 0.48 (0.22-0.75) at an intratumoral susceptibility signal threshold ≥1, 0.85 (0.74-0.91) and 0.93 (0.84-0.97) at threshold ≥2, and 0.72 (0.59-0.82) and 0.97 (0.93-0.99) at threshold ≥3. Molecular findings were heterogeneous and summarized descriptively, with higher intratumoral susceptibility signal burden most consistently associated with isocitrate dehydrogenase wild-type status.

Limitations

Studies were predominantly retrospective and single-center, with heterogeneous intratumoral susceptibility signal scoring, imaging protocols, and World Health Organization reference standards. Some contingency tables required reconstruction.

Conclusions

Intratumoral susceptibility signals showed threshold-dependent performance for distinguishing World Health Organization grade III-IV from grade II gliomas. Among the prespecified ordinal thresholds, a threshold ≥2 provided the most balanced sensitivity-specificity profile. Molecular evidence remains exploratory.