Related Experiment Video
Updated: Aug 12, 2025
Modeling Brain Metastases Through Intracranial Injection and Magnetic Resonance Imaging
Published on: June 7, 2020
Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal
Assaf Berger1, Matthew D Lee2, Eyal Lotan2
1Department of Neurological Surgery, NYU Langone Health Medical Center, New York University, New York, New York, USA.
Background:
Differentiating brain metastasis progression from radiation effects or radiation necrosis (RN) remains challenging. Golden-angle radial sparse parallel (GRASP) dynamic contrast-enhanced MRI provides high spatial and temporal resolution to analyze tissue enhancement, which may differ between tumor progression (TP) and RN.
Objective:
To investigate the utility of longitudinal GRASP MRI in distinguishing TP from RN after gamma knife stereotactic radiosurgery (SRS).
Methods:
We retrospectively evaluated 48 patients with brain metastasis managed with SRS at our institution from 2013 to 2020 who had GRASP MRI before and at least once after SRS. TP (n = 16) was pathologically confirmed. RN (n = 16) was diagnosed on either resected tissue without evidence of tumor or on lesion resolution on follow-up. As a reference, we included a separate group of patients with non-small-cell lung cancer that showed favorable response with tumor control and without RN on subsequent imaging (n = 16). Mean contrast washin and washout slopes normalized to the superior sagittal sinus were compared between groups. Receiver operating characteristic analysis was performed to determine diagnostic performance.
Results:
After SRS, progression showed a significantly steeper washin slope than RN on all 3 follow-up scans (scan 1: 0.29 ± 0.16 vs 0.18 ± 0.08, P = .021; scan 2: 0.35 ± 0.19 vs 0.18 ± 0.09, P = .004; scan 3: 0.32 ± 0.12 vs 0.17 ± 0.07, P = .002). No significant differences were found in the post-SRS washout slope. Post-SRS washin slope differentiated progression and RN with an area under the curve (AUC) of 0.74, a sensitivity of 75%, and a specificity of 69% on scan 1; an AUC of 0.85, a sensitivity of 92%, and a specificity of 69% on scan 2; and an AUC of 0.87, a sensitivity of 63%, and a specificity of 100% on scan 3.
Conclusion:
Longitudinal GRASP MRI may help to differentiate metastasis progression from RN.
Insights
Longitudinal GRASP MRI shows promise in distinguishing tumor progression from radiation necrosis after stereotactic radiosurgery. The washin slope analysis of dynamic contrast-enhanced MRI can aid in differentiating these conditions.
Area of Science:
- Radiology
- Oncology
- Medical Imaging
Background:
- Differentiating brain metastasis tumor progression (TP) from radiation necrosis (RN) post-stereotactic radiosurgery (SRS) is clinically challenging.
- Golden-angle radial sparse parallel (GRASP) dynamic contrast-enhanced MRI offers high spatiotemporal resolution for analyzing tissue enhancement patterns.
Purpose of the Study:
- To evaluate the effectiveness of longitudinal GRASP MRI in differentiating TP from RN following gamma knife SRS.
- To assess quantitative MRI parameters for improved diagnostic accuracy.
Main Methods:
- Retrospective analysis of 48 brain metastasis patients treated with SRS, including pre- and post-SRS GRASP MRI scans.
- Pathological confirmation for TP (n=16) and diagnosis of RN (n=16) based on tissue or imaging follow-up.
- Comparison of normalized contrast washin and washout slopes between groups, with ROC analysis for diagnostic performance.
Main Results:
- Significantly steeper post-SRS washin slopes were observed in TP compared to RN across all three follow-up scans (P < .021).
- No significant differences in post-SRS washout slopes were found between TP and RN.
- The washin slope demonstrated good diagnostic performance, with AUCs ranging from 0.74 to 0.87 for differentiating TP from RN.
Conclusions:
- Longitudinal GRASP MRI, particularly the analysis of washin slope, shows potential as a non-invasive tool for differentiating tumor progression from radiation necrosis after SRS.
- Quantitative assessment of enhancement kinetics may improve diagnostic accuracy in managing brain metastases treated with radiation.
