Contrast-enhanced T2-fluid-attenuated inversion recovery magnetic resonance imaging for radiotherapy target delineation in brain metastases: A narrative review

Table 3 Summary of key clinical studies of contrast-enhanced T2-fluid-attenuated inversion recovery sequence in brain metastases

Ref.	Population	Sample size	Contrast agent/dose	Acquisition setting	Comparator	Primary outcome	Key limitations
Jin et al[33]	Patients with suspected BM	82	Half-dose	Diagnostic	Standard-dose T1WI + C	Lesion detection rate; contrast-to-noise ratio comparison	Single-center; no radiotherapy contouring endpoint
Ahn et al[31]	Patients with small BM	121	Double-dose	Diagnostic	Conventional 3D T1WI + C	Detection sensitivity for small BM	Diagnostic cohort only; no radiotherapy application
Sun et al[18]	Lung cancer patients with BM	156	Standard-dose	Diagnostic	T1WI + C alone	Overall lesion detection rate	Diagnostic study; no target delineation analysis
Heyn et al[123]	BM patients post-radiotherapy	98	Standard-dose	Diagnostic follow-up	DSC-MRI	Differentiation of radiation necrosis vs tumor progression	Retrospective; single-center
Ohira et al[53]	BM patients undergoing SRS	41	Standard-dose	Radiotherapy simulation	CT simulation	Geometric distortion and dosimetric impact	Focused on distortion, not contour accuracy

All available evidence is derived from diagnostic imaging or geometric distortion studies. No prospective study has directly evaluated the impact of contrast-enhanced T2-fluid-attenuated inversion recovery on Gross Tumor Volume contouring accuracy, interobserver variability, dosimetric outcomes, or patient survival. T1WI + C: Contrast-enhanced T1-weighted imaging; CT: Computed tomography; DSC-MRI: Dynamic susceptibility contrast magnetic resonance imaging; BM: Brain metastases; SRS: Stereotactic radiosurgery.