Role of Contrast-Enhanced MRI in Diagnosing Brain Metastases in Patients With Lung Cancer

Introduction: Lung cancer is one of the most common cancers in the world. Approximately 40% of all metastases make up brain metastases that occur in 3% of patients at early stages of lung cancer. Early diagnosis of brain metastases directly affects patients’ survival and quality of life. Objective: To study the role of contrast-­enhanced magnetic resonance imaging (MRI) in detecting brain metastases at the outpatient stage in patients with newly diagnosed and histologically confirmed lung cancer and to compare the findings to that of computed tomography (CT). Materials and methods: Our study was conducted at the premises of the Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation) between November 2022 and January 2023. Seventy­five patients with histologically confirmed lung cancer underwent brain MRI on a Philips Panorama 1.0T MRI scanner and intravenous administration of Clariscan to detect metastatic lesions. As a diagnostic method, we used a “short” scanning protocol in T1­-WI (TR: 450, TE: 15, slice thickness 5 mm), T2­-WI (TR: 4533, TE: 100, slice thickness 5 mm) and DWI (TR: 3712, TE: 97, slice thickness 5 mm) modes in the axial plane, then the Clariscan contrast agent was injected intravenously at the rate of 0.2 ml per 1 kg of the patient's weight, after which the scan was repeated using 3D T1 (TR: 450, TE: 15, slice thickness 1 mm). Results: The average age of the patients was 60 years. The majority of the participants were male. Of all the patients, the majority had central lung cancer (57.3%). During contrast-­enhanced brain MRI, brain metastases that accumulated a contrast agent in 100% of cases were detected in 30 patients (40%) of the total number of patients. In 7% of the patients, there were non-­metastatic findings undetected by prior contrast­-enhanced CT, such as pontine cavernoma and venous malformations. After MRI for brain metastases, management strategies changed in 30 (40%) patients. Discussion: Contrast-­enhanced MRI is one of the most effective methods for diagnosing metastatic lesions. It allows to localize brain metastases and helps the clinician choose the most effective management strategy. The introduction of contrast­-enhanced brain MRI into routine medical practice could improve the accuracy and quality of brain metastasis detection in patients with lung cancer.