Fluid Suppression Techniques Combined With Amide Proton Transfer-Weighted Imaging for the Evaluation of Adult-Type...

To evaluate the diagnostic potential of fluid suppression (FS) techniques combined with amide proton transfer-weighted imaging (APTw) for assessment of isocitrate dehydrogenase (IDH) mutation status, glioma subtypes, and tumor proliferation.

This retrospective study included 117 patients with adult-type diffuse gliomas. Conventional APTw, FS-APTw, and spillover-corrected FS-APTw (SCFS-APTw) metrics were calculated from 3T MRI data in tumor parenchyma, necrotic or cystic regions, and contralateral normal-appearing white matter. APTw signals were compared across the three techniques within each region, between IDH-mutant and IDH-wildtype gliomas, and among astrocytoma, oligodendroglioma, and glioblastoma subtypes. Diagnostic performance for distinguishing IDH mutation status and glioma subtypes was assessed using receiver operating characteristic (ROC) analysis. Correlations between APTw metrics and Ki-67 expression were also analyzed.

Both FS-APTw and SCFS-APTw significantly reduced signal intensity in tumor parenchyma and necrotic or cystic regions, with SCFS-APTw demonstrating a stronger suppression effect. IDH-wildtype gliomas showed significantly higher APTw metrics than IDH-mutant gliomas (all P < 0.001). Glioblastomas exhibited significantly higher metrics than oligodendrogliomas (all corrected P ≤ 0.015) and astrocytomas (all corrected P < 0.001). SCFS-APTw achieved the highest area under the ROC curve (AUC) of 0.846 for identification of IDH mutation status. For differentiation between astrocytomas and glioblastomas, the 90th percentile of APTw yielded the highest AUC (0.860), followed by SCFS-APTw (0.849). For discrimination between oligodendrogliomas and glioblastomas, the highest AUC (0.832) was obtained using the 90th percentile of SCFS-APTw. None of these metrics successfully differentiated oligodendrogliomas from astrocytomas. SCFS-APTw demonstrated the strongest correlation with Ki-67 expression (r = 0.451).

FS techniques effectively reduce elevated APTw signals originating from fluid compartments. Their combination with APTw imaging enables evaluation of IDH mutation status, glioma subtypes, and tumor proliferative activity in adult-type diffuse gliomas.