CLTR-05 MAGNETIC RESONANCE IMAGING (MRI) LONGITUDINAL RELAXATION TIME T1 OF GREY MATTER AMONG PATIENTS WITH METASTATIC BREAST CANCER: A SECONDARY ANALYSIS OF THE SYMPTOM TRIAL [NCT03881605]
Wilfred Lam, Jenny Zhu, Katarzyna Jerzak, Arjun Sahgal, Greg StaniszAbstract
Background
The longitudinal magnetization relaxation time (T1) is being explored for the early detection of changes in normal appearing grey matter (GM) and white matter (WM), which may identify brain metastases (BrM) earlier than conventional contrast-enhanced MRI.
Methods
Eleven women with either HER2 + (n = 8) or triple negative (TN; n = 3) metastatic breast cancer but no known BrM were scanned on a 3 tesla (3 T) MRI. A standard contrast-enhanced T1-weighted scan and quantitative T1 mapping scans were acquired at up to four time points: baseline and 4, 8, and 12 months. One TN breast cancer patient developed BrM in the post-study follow-up period (imaged at 8 months after enrollment, which was 6.4 months before BrM diagnosis) and another TN breast cancer patient (not part of the SYMPToM trial; imaged after BrM diagnosis) was included for comparison. GM and WM were automatically segmented. The T1 of all segmented voxels was compared between breast cancer type and between patients who did and did not develop BrM using Wilcoxon rank sum exact tests.
Results
Research-based MRI sequences were compared between two patients who developed BrM (two TN) and six patients did not develop BrM (five HER2+, one TN). The GM T1 in the patients who developed BrM was 1.94 ± 0.05 s (mean ± standard deviation) compared to 1.78 ± 0.06 s for the non-BrM group. However, the difference did not reach statistical significance (p = 0.07).
Discussion
Elevated T1 in GM could indicate glial inflammation before the onset of BrM. A larger population of patients could potentially confirm whether this could allow earlier identification of TN breast cancer BrM.