Objective:To study the MRI characteristics of solitary brain metastasis(SBM)

and to improve the diagnostic accuracy of SBM.Methods:MRI plain imaging and contrast enhancement imaging of 49 patients with SBM proven by pathology and clinical evidence were analyzed retrospectively.Results:Of the 49 cases of SBM

44 lesions(89.9%)were located at the supra-tentorial regions

and 5 lesions(10.1%)were located at the infratentorial regions;29 lesions(65.9%)were located at the right cerebrum

and 15 lesions(34.1%)were located at the left cerebrum;5 lesions(10.1%) were located at the cerebel;42 lesions(95.5%) were located at the cerebral cortex and subcortical regions.All lesions were enhanced markedly

including un-uniformity enhancement in 26 cases(53.1%)

nodular enhancement in 12 cases(24.5.1%)

solid-cystic mass in 10 cases(20.4%)

combined bleeding in 1 case(2%).Conclusion:SBM has some characteristic features in MRI imaging.Contrast enhanced MRI images show important value in the diagnosis and differential diagnosis of SBM.