Magnetic resonance imaging patterns of brain metastases among Patients with intracranial neoplasms at Muhimbili National Hospital And Muhimbili Orthopedic Institute

Abstract

ABSTRACT Background: Metastatic brain lesions, have exhibited an increasing incidence paralleling advancement in cancer therapeutics. Diagnosis of brain metastases often involves MRI findings and clinical history. Despite advancements in diagnostic modalities, brain metastases continue to pose a challenge in differentiating it from other primary intracranial malignancies. This necessitates increasing precision of diagnostic tools. This study aimed to investigate the MRI patterns of brain metastases among patients with intracranial neoplasms in a regional context. Objective: To determine MRI patterns of brain metastases among patients with intracranial neoplasms at Muhimbili National Hospital (MNH) and Muhimbili Orthopaedic Institute (MOI) from October 2023 to March 2024. Material and Methods: A prospective cross-sectional study was conducted at the Department of Radiology and Medical Imaging at MNH and MOI. The study included 124 consecutive patients with intracranial neoplasms from October 2023 to March 2024. Statistical analysis was conducted using SPSS version 27. Continuous data were summarized with measures of central tendency and dispersion, while categorical data were presented as frequencies and percentages. Independent student t-tests were applied to compare means of continuous variables between two groups. Fisher’s exact tests and bivariate and multivariate logistic regression analysis were employed to assess the associations, with a significance threshold of p < 0.05. Results: The study comprised 124 consecutive patients diagnosed with intracranial neoplasms by MRI, with a mean age of 45.11 ± 19.434 years, and females accounting for 56.5%. Brain metastases constituted 21.0% of all intracranial neoplasms, with breast cancer as the leading primary malignancy, followed by lung cancer. Patients with brain metastases exhibited a significantly higher mean age compared to those with primary intracranial neoplasms (52.5 years vs. 43.15 years, p = 0.029) and a higher frequency among females (24.3% vs. 16.7%, p = 0.301). Brain metastases were significantly more likely to present as multiple lesions compared to primary intracranial neoplasms (76.9% vs. 9.2%, p < 0.001), with 32.46 higher odds (p < 0.001), and were more likely to occupy the grey-white matter junction (76.9% vs. 5.1%, p < 0.001), with 81.1 higher odds (p < 0.001). Additionally, brain metastases were more likely to exhibit ring enhancements (53.8% vs. 11.2%, p < 0.001), with 9.08 higher odds (p < 0.001), and to have perilesional edema (92.3% vs. 60.2%, p = 0.002), with 7.67 higher odds (p = 0.009), along with more than 0.5 cm shift of midline structures (57.7% vs. 17.3%, p = 0.000), with 9.56 higher odds (p < 0.001), and higher mean PED/GTD ratio (2.2914 vs. 1.5783, p < 0.001). Conversely, brain metastases were less likely to present with poorly defined margins (3.8% vs. 30.6%, p < 0.001), with 0.09 lower odds (p < 0.019), irregular shapes (3.8% vs. 56.1%, p < 0.001), with 0.03 lower odds (p < 0.001), and to exhibit peri-enhancement fluid restrictions (7.7% vs. 31.6%, p < 0.013), with 0.19 lower odds (p < 0.032), when compared to primary intracranial neoplasms. Conclusion: The likelihood of cerebral lesions as seen on MRI of patients with a known primary malignancy being due to metastasis is high on older patients, 50 years and above with multiple, round, ring-enhancing lesions with clearly defined margins at the grey-white matter junction. The likelihood is further enhanced by massive perilesional edema without areas of low ADC signal, sparing the cortex. Notably, not all solitary lesions are primary neoplasms. Recommendation: Patients over 50 years with the imaging patterns demonstrating high likelihood for metastases and a known systemic malignancy may proceed with treatment options without biopsy from intracranial lesion(s) for histopathology. Keywords: Brain metastases, Intracranial tumors, Brain MRI patterns, Primary Extracranial malignancies.