Objective:To determine the efficacy of contrast enhanced T2 fluid attenuated inversion recovery(CE-T2 FLAIR)sequence and contrast enhanced T1 weighted imaging(CE-T1WI)of brain metastases after injection of different doses of gadolinium contrast agent,and to investigate the clinical value of half-dose contrast agent enhanced T2 FLAIR sequence in the diagnosis of brain metastases.Materials and Methods:A total of 30 patients with a history of extracranial primary malignant tumors confirmed by pathological diagnosis and brain metastases confirmed by pathological or clinical follow-up were prospectively enrolled.On the basis of conventional non-enhanced T1WI and T2 FLAIR sequences using a 3.0 T MRI equipment,CE-T2 FLAIR and CE-T1WI scans were performed after administration of half-dose(0.05 mmol/kg)gadolinium-based contrast agent(GBCA),followed by fractional supplementation of GBCA to the conventional-dose(0.1 mmol/kg)and double-dose(0.2 mmol/kg).After injection of the GBCA,both CE-T2 FLAIR and CE-T1WI scans were performed.Objective measurements of images were performed by two observers.The contrast-to-noise ratio(CNR),relative-contrast(RC),and percentage increase(PI)of CE-T2 FLAIR and CE-T1WI images under different doses were calculated.Analysis of variance were used to analyze objective measurements between different groups and multiple comparisons were performed when the difference was statistically significant(P＜0.05).The t-test was used to analyze the differences between two groups.Results:The objective scores were consistent between two observers.There was no significant difference in CNR and RC values among CE-T2 FLAIR images under three different doses of GBCA(P＞0.05).Compared with non-enhanced T2 FLAIR scanning,the PI of the lesion was increased.There were significant differences in the CNR and RC values between the CE-T1WI images at three different doses of GBCA(P＜0.05).The results of pairwise comparison showed that the CNR and RC values on the doubling-dose CE-T1WI images were significantly higher than those on the half-dose group(P＜0.05).The CNR and RC values of CE-T2 FLAIR images at half-dose and conventional-dose were significantly increased compared to CE-T1WI in this group,and the difference was statistically significant(P＜0.05).The CNR and RC values of the half-dose CE-T2 FLAIR images were higher than those of the conventional-dose CE-T1WI(P＜0.05).Compared with doubling-dose CE-T1WI,the CNR value of the half-dose CE-T2 FLAIR image increased(P＜0.05),while the difference in RC value was not statistically significant(P＞0.05).Conclusions:In comparison with CE-T1WI,the CE-T2 FLAIR sequence with half-dose GBCA could achieve similar image quality and show values in clinical diagnosis of brain metastases.
维普
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