BACKGROUND: Advances in oncology in recent years have made it possibleto undertake radical interventions even in advanced cases. Local treatment, surgical or radiosurgical,is applied ever more frequently in cases of metastases to the brain. This requires accurate determinationof the number and location of metastases by means of imaging techniques. The goal of our research wasto establish whether the use of sequences delayed by 20-30 minutes after gadolinium injection improvesthe number of metastatic lesions detected in the brain by MRI. MATERIAL/METHODS: Twenty-eight patientswere studied, ranging in age from 24 to 72 years, diagnosed with malignant tumors and suspected metastasesto the brain. MRI examinations were performed with a 2T unit in SE T1 immediately after i.v. administrationof a 0.1 mmol/kg dose of gadolinium, and again 20-30 minutes after contrast injection; both sequenceswere done in axial projection in layers identical as in the SE T1 sequence made before gadolinium injection.The focal lesions were counted and classified by size. The number of detected lesions was calculatedin each group, comparing early and late phases after contrast injection. RESULTS: The number of all nodulesfound in the delayed sequences was significantly higher in comparison to the early phase after gadoliniuminjection. CONCLUSIONS: Delayed sequence should be used to supplement basic sequences in the diagnosisof malignant metastases to the brain in selected oncological cases.

Keywords: Brain, Contrast Media, Gadolinium DTPA, Magnetic Resonance Imaging, Sensitivity and Specificity