Intratumoral susceptibility signals in adult-type diffuse gliomas: associations with molecular profile, tumor grade, and overall survival

Purpose: Intratumoral Susceptibility Signals (ITSS) are low-signal-intensity structures observed on susceptibility-weighted imaging (SWI) which may reflect intratumoral microhemorrhages, calcifications, and neovascularization. Previous studies have demonstrated associations between ITSS, glioma grade, and molecular characteristics; however, their potential role in outcome prediction remains incompletely defined. This study investigated the diagnostic and and potential prognostic role of ITSS in adult diffuse gliomas.Methods: We retrospectively analyzed 128 adult patients with histologically confirmed diffuse gliomas who underwent preoperative MRI including SWI. ITSS were graded from 0 to 3 according to the number of susceptibility signals. Associations between ITSS grade and CNS WHO tumor grade, IDH mutation status, MGMT promoter methylation and Ki-67 labeling index (LI) were evaluated. Overall survival (OS) was assessed using Kaplan–Meier analysis and Cox proportional hazards models.Results: ITSS grade was significantly associated with WHO glioma grade (p < 0.001), with lower-grade tumors predominantly exhibiting ITSS grades 0–1 and higher-grade gliomas showing grades 2–3. IDH-mutant gliomas displayed significantly lower ITSS grades than IDH-wildtype tumors (p < 0.001). ITSS grade was positively correlated with Ki-67 labeling index (Spearman's ρ = 0.423, p < 0.001). In the survival cohort (n = 87) higher ITSS burden was significantly associated with shorter OS (ITSS 2–3 vs. 0–1: HR = 3.19, 95% CI 1.65–6.19; p < 0.001). However, this association was no longer significant after adjustment for established prognostic factors (HR = 1.40, 95% CI 0.69–2.86; p = 0.350), with IDH status emerging as the strongest independent association with shorter OS.Conclusion: ITSS grading on SWI is associated with CNS WHO grade, molecular profile, proliferative activity, and OS in adult-type diffuse gliomas. Although ITSS was not an independent predictor of survival after adjustment for established prognostic factors, it may serve as a readily available, non-invasive imaging correlate of tumor aggressiveness, providing complementary information for preoperative tumor characterization while definitive molecular data are pending.