Volumetric Postcontrast T1 Turbo Spin-Echo vs Gradient-Recalled Echo MR Sequences for Detecting Brain Metastases: A Systematic Review and Meta-Analysis.

Abstract

Background: Contrast-enhanced 3D T1-weighted MRI is the imaging reference for detection and follow-up of brain metastases. Volumetric GRE-based sequences, such as MPRAGE, are widely used but remain prone to susceptibility and lower lesion conspicuity. 3D black-blood TSE-based sequences, such as sampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE), have been increasingly embedded into routine workflow and are thought to improve lesion detection in part through vessel signal suppression.

Purpose: We aimed to investigate the comparative diagnostic performance of 3D T1 TSE vs GRE sequences for the detection of brain metastases.

Data sources: Studies comparing the diagnostic performance of postcontrast 3D T1 TSE and GRE sequences in adults with brain metastases were searched on MEDLINE, EMBASE, Cochrane Central, Google Scholar, and PROSPERO, from inception through April 2025.

Study selection: Fifteen studies encompassing 544 patients with 4338 metastases were included.

Data analysis: Data on diagnostic accuracy parameters, image quality, and interrater agreement were extracted. Random-effects models were applied to compute pooled sensitivity and comparative OR for lesion detection. Risk of bias was assessed using QUADAS-2 and QUADAS-C tools.

Data synthesis: Pooled sensitivities for detection of brain metastases were 97.4% (95% CI, 93.2%-99.0%) for TSE- and 76.1% (95% CI, 69.3-81.9) for GRE-based sequences, with a comparative OR of 12.0 (95% CI, 5.45-26.6; P < .0001). Detectability of small lesions (<5 mm) was significantly better on TSE (96.1%; 95% CI, 87.7-98.8) than GRE (58.4%; 95% CI, 47.9-68.2), although both techniques performed comparably for larger (≥5 mm) lesions (98.2% for TSE, 94.4% for GRE). OR estimates were 17.2 (95% CI, 4.50-66.1) for small and 2.81 (95% CI, 0.92-8.56) for large lesions. Contrast-to-noise ratio and interrater agreements were slightly higher on TSE than GRE. False-positives (FPs) were more common with TSE, mostly related to incomplete vessel suppression (49 FP counts in TSE, 35 in GRE).

Limitations: Our meta-analysis is limited by high heterogeneity, case-only studies, possible small-study effects, and high risk of bias for the reference standard domain.

Conclusions: Postcontrast 3D T1 TSE sequences provide higher sensitivity and improved lesion conspicuity compared with GRE sequences, particularly for small metastases, although at the cost of slightly higher FPs.