Improved detection of brain metastases using contrast-enhanced 3D black-blood TSE sequences compared to post-contrast 3D T1 GRE: a comparative study on 1.5-T MRI.

Objectives: Brain metastases are the most common intracranial malignancy in adults, and their detection is crucial for treatment planning. Post-contrast 3D T1 gradient-recalled echo (GRE) sequences are commonly used for this purpose, but contrast-enhanced 3D T1 turbo spin-echo (TSE) sequences with motion-sensitized driven-equilibrium (MSDE) technique ("black blood") may offer improved detection. This study aimed to compare the effectiveness of contrast-enhanced 3D black blood sequences to standard 3D T1 GRE sequences in detecting brain metastases on a 1.5-T MRI.

Materials and methods: A retrospective analysis of 183 patients with suspected or follow-up brain metastases between May 2022 and September 2023 was conducted. Among these patients, 107 were included in the final analysis. Both post-contrast 3D T1 GRE and 3D black blood sequences were acquired on the same scanner with similar acquisition times. Two neuroradiologists independently evaluated the images for the number, size, and location of metastases. Interobserver variability and statistical analysis were performed.

Results: Among the 107 patients (mean age 60.8 years ± 13.2 years; 55 males, 52 females), 3D black blood sequences detected a significantly higher number of brain metastases, particularly small lesions (< 5 mm), compared to 3D T1 GRE sequences (p < 0.05). There was no significant difference in detecting large metastases (≥ 5 mm) between the sequences. In addition, the black blood sequences provided better conspicuity of metastases in the majority of patients (85%).

Conclusion: Contrast-enhanced 3D T1 TSE with MSDE ("black blood") sequences offer improved detection of brain metastases, especially small lesions, on 1.5-T MRI compared to standard 3D T1 GRE sequences.

Key points: Question Accurate identification of the number and location of brain metastases using MRI is essential for planning and managing effective treatment. Findings Contrast-enhanced 3D T1 TSE black blood sequences detected significantly more small brain metastases than standard 3D T1 GRE sequences on 1.5-T MRI. Clinical relevance The use of 3D black blood sequences on 1.5-T MRI may have the potential to improve the accuracy of detection of brain metastases, leading to better treatment planning and potentially improved patient outcomes.