Improving glioblastoma delineation through TR and flip angle optimization in post-contrast t1-weighted MRI at 1.5 tesla

Background: Accurate glioblastoma imaging after contrast administration is vital for surgical planning, radiotherapy targeting, and monitoring. Comparative evidence on protocol performance and parameter optimization at 1.5 Tesla remains limited. Purpose: To compare two post-contrast T1-weighted MRI protocols—GEM-LT (gradient-echo-based) and TESIP (spin-echo-based)—and evaluate the impact of repetition time (TR) and flip angle (FA) refinement on lesion conspicuity. Methods: Fifty patients with histopathologically confirmed glioblastoma underwent 1.5T MRI using GEM-LT and TESIP protocols. TESIP was tested in standard form (TR = 500 ms, FA = 90°) and modified form (TR = 700 ms, FA = 110°). Signal intensity (SI) was measured from 30 ROIs per patient, targeting the enhancing tumor core, peritumoral edema, and contralateral white matter. Statistical comparisons used one-way ANOVA with LSD post-hoc tests; effect sizes were reported. Results: TESIP produced higher mean SI than GEM-LT (2082.97 ± 128.05 vs. 1931.83 ± 126.75; p < 0.001; η² = 0.264). Parameter refinement in TESIP further increased SI (2187.12 ± 130.45; p < 0.001; η² = 0.142) and enhanced border sharpness without extending scan time. Clearer lesion margins and fewer susceptibility artefacts, particularly close to the base of the skull, were confirmed by the qualitative review. Conclusion: In postcontrast glioblastoma imaging, TESIP performs better than GEM-LT at 1.5 Tesla. Enhancing TR and FA promotes its adoption in standard neuro-oncologic practice by improving lesion visualisation without lowering efficiency.