Efficacy of 3D-TSE Sequence in Prolonging Time to Distant Intracranial Failure: A Session-Wise Analysis in a Histology-Diverse Patient Cohort

Academic Background

Brain metastases (BM) represent the majority of intracranial malignancies and significantly contribute to cancer-related morbidity and mortality. At the initial diagnosis of systemic cancer, approximately 15% of patients at any stage and up to 30% of stage IV patients are diagnosed with brain metastases, potentially rising to 50% during systemic disease progression. With the increased availability of magnetic resonance imaging (MRI) and the implementation of staging guidelines, the incidence of brain metastases has significantly increased. However, despite the effectiveness of whole-brain radiotherapy (WBRT) in treating brain metastases, its negative impact on neurocognitive function has made stereotactic radiosurgery (SRS) or fractionated stereotactic radiosurgery (fSRS) a preferred option. Nevertheless, SRS treatment still faces the risk of distant intracranial failure (DIF), particularly when small metastases are not adequately detected by conventional imaging techniques.

Research Objective

This study aims to evaluate the impact of integrating the 3D fast/turbo spin echo (3D-TSE) sequence into SRS practice on the detection of brain metastases and the prolongation of DIF time. The research team hopes that this technological improvement will enhance the detection rate of brain metastases, thereby extending the DIF time in patients, especially those with limited intracranial disease and not receiving central nervous system (CNS)-active agents.

Source of the Paper

This paper was authored by Eyub Y. Akdemir, Selin Gurdikyan, Muni Rubens, and others from the Miami Cancer Institute, Baptist Health South Florida, and was published in Neuro-Oncology in 2025. The corresponding author is Rupesh Kotecha, the Director of the Department of Radiation Oncology at the Miami Cancer Institute.

Research Process

Data Collection

Upon approval by the Institutional Review Board, the research team included adult patients who underwent SRS/fSRS at the Miami Cancer Institute between February 2019 and January 2024. Exclusion criteria included prior WBRT, Karnofsky Performance Status (KPS) scores below 60, small cell lung cancer, and hematologic malignancies. Data collected included patient gender, race, age, tumor histology, intracranial disease burden, and systemic therapy status. All patients underwent post-contrast MPRAGE sequence imaging at a 3 Tesla magnetic field, and starting from February 2020, the 3D-TSE sequence was introduced as a supplement to SRS/fSRS treatment planning.

Research Methods

The study was divided into two cohorts: the control cohort (using only the MPRAGE sequence) and the primary cohort (using both MPRAGE and 3D-TSE sequences). The median time to DIF was estimated using the Kaplan-Meier method, and factors influencing DIF were analyzed using the Cox proportional hazards model.

Results Analysis

The study included 308 patients who underwent 467 SRS treatments for 1918 brain metastases. The control cohort consisted of 92 patients who underwent 135 treatments, while the primary cohort included 216 patients who underwent 332 treatments. The introduction of the 3D-TSE sequence increased the detection rate of brain metastases by 24%, particularly in patients with 1-4 metastases and solitary metastases, significantly prolonging the time to DIF. Specifically, the median time to DIF was 11.4 months in the primary cohort compared to 6.8 months in the control cohort (p = 0.029). In patients not receiving CNS-active agents, the integration of the 3D-TSE sequence showed a trend toward prolonging the time to DIF.

Research Conclusions

This study demonstrates that integrating the 3D-TSE sequence into SRS practice can significantly improve the detection rate of brain metastases and prolong the time to DIF, especially in patients with limited intracranial disease and not receiving CNS-active agents. These findings provide strong support for optimizing SRS treatment workflows and have significant clinical application value.

Research Highlights

1. Integration of the 3D-TSE Sequence Significantly Improves the Detection Rate of Brain Metastases: The study shows that the introduction of the 3D-TSE sequence increased the detection rate of brain metastases by 24%, particularly excelling in the detection of small metastases.

2. Prolongation of DIF Time: The median time to DIF in the primary cohort was significantly longer than in the control cohort, especially in patients with 1-4 metastases and solitary metastases, where the prolongation of DIF time was more pronounced.

3. Clinical Application Value: The research results provide new insights for optimizing SRS treatment, particularly in patients not receiving CNS-active agents, where the integration of the 3D-TSE sequence may lead to better treatment outcomes.

Other Valuable Information

The study also found that the 3D-TSE sequence excels in detecting small metastases near cortical vessels, venous sinuses, dura mater, and the brain surface, providing new technical means for the precise treatment of brain metastases in the future. Additionally, the research team emphasized the potential role of the 3D-TSE sequence in reducing false-positive lesions and optimizing treatment planning.

Through this study, the application prospects of SRS in the management of brain metastases have been further expanded, and the introduction of the 3D-TSE sequence is expected to become one of the standard procedures in the future treatment of brain metastases.