Intratumoral hemorrhage in brain metastases: a correlation with imaging characteristics and vasogenic edema

This study investigated the relationship between intratumoral hemorrhage detected on brain magnetic resonance imaging (MRI) and patients' demographic characteristics, primary tumor type/subtype, radiological features of metastases, and potential impact on survival. Our institution's Non-Interventional Research Ethics Committee approved this study.

Two hundred twenty-five patients diagnosed with brain metastases based on contrast-enhanced MRI were analyzed retrospectively between August 2017 and June 2023. Demographic data, primary malignancy type/subtype, imaging characteristics, and survival outcomes were recorded. Intratumoral hemorrhage was identified as low-signal intensity areas on T2*-weighted gradient echo (T2*-GRE) or susceptibility-weighted imaging (SWI). Patients were classified into hemorrhagic and non-hemorrhagic groups. The groups were compared with respect to age, sex, tumor type/subtype, number, localization, size, peritumoral edema, and edema-to-tumor ratio. In patients with vasogenic edema, the ratio of the largest edema diameter to tumor diameter was calculated to assess its association with hemorrhage.

Intratumoral hemorrhage was detected in 90 patients (40%). Hemorrhage prevalence varied by primary cancer: malignant melanoma (75%), renal cell carcinoma (50%), ovarian cancer (50%), lung cancer (35.2%), and breast cancer (28.2%) (χ² = 22.425, p < 0.001). Hemorrhagic lesions demonstrated significantly larger size (Z = -2.569, p < 0.001), greater edema extent (Z = -4.725, p < 0.001), and higher edema/tumor ratios (Z = -2.857, p = 0.004). Hemorrhage was most frequent in triple-negative breast cancer (χ² = 8.383, p = 0.015) and in lung adenocarcinomas (χ² = 5.850, p = 0.016). No statistically significant difference in overall survival was observed between patients with hemorrhagic and non-hemorrhagic metastases (p = 0.352).

Intratumoral hemorrhage rates vary across primary tumor types. Its presence correlates with larger lesion size and extensive vasogenic edema, suggesting potential diagnostic and prognostic value in evaluating brain metastases.