Differentiation between glioblastomas and solid brain metastases using amide proton transfer-weighted (APTw) MRI with and without fluid suppression.

OBJECT Accurate differentiation between glioblastomas (GBM) and solitary brain metastases (MET) is crucial for treatment planning. This study evaluated the ability of amide proton transfer-weighted (APTw) MRI with and without fluid suppression (FS) to distinguish between GBM and MET.

Method

Thirty-two patients with histopathologically confirmed GBM (n = 24) or MET (n = 8) were included. Post-processing included creation of APTw maps without FS, with patient-specific FS based on the patient's white matter values and with a fixed-factor FS. Regions of interest (ROIs) were segmented in the contrast-enhanced tumour, peritumoural oedema, necrosis and the normal-appearing white matter (NAWM). The min, max and mean signals were extracted for each ROI and normalised to NAWM, creating normalised APTw (nAPTw) values. Group differences were determined with t test and Mann-Whitney U test. Diagnostic performance was assessed using receiver operating characteristic (ROC) analysis.

Results

Both FS methods significantly reduced nAPTw values in tumour regions. Patient-specific FS showed highest performance in distinguishing GBM from MET in the necrotic (AUC 0.921) and oedematous regions (AUC 0.698). Fixed FS provided minor to intermediate improvements.

Conclusion

Patient-specific fluid suppression increased the diagnostic performance of APTw imaging in differentiating GBM from MET, particularly in oedematous and necrotic regions.