PT  - JOURNAL ARTICLE
AU  - Jin, T.
AU  - Ge, M.
AU  - Huang, R.
AU  - Yang, Y.
AU  - Liu, T.
AU  - Zhan, Q.
AU  - Yao, Z.
AU  - Zhang, H.
TI  - Utility of Contrast-Enhanced T2 FLAIR for Imaging Brain Metastases Using a Half-dose High-Relaxivity Contrast Agent
AID  - 10.3174/ajnr.A6931
DP  - 2020 Dec 24
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2020/12/24/ajnr.A6931.short
4100  - http://www.ajnr.org/content/early/2020/12/24/ajnr.A6931.full
AB  - BACKGROUND AND PURPOSE: Efficient detection of metastases is important for patient’ treatment. This prospective study was to explore the clinical value of contrast-enhanced T2 FLAIR in imaging brain metastases using half-dose gadobenate dimeglumine.MATERIALS AND METHODS: In vitro signal intensity of various gadolinium concentrations was explored by spin-echo T1-weighted imaging and T2 FLAIR. Then, 46 patients with lung cancer underwent nonenhanced T2 FLAIR before administration of half-dose gadobenate dimeglumine and 3 consecutive contrast-enhanced T2 FLAIR sequences followed by 1 spin-echo T1WI after administration of half-dose gadobenate dimeglumine. After an additional dose of 0.05 mmol/kg, 3D brain volume imaging was performed. All brain metastases were classified as follows: solid-enhancing, ≥ 5 mm (group A); ring-enhancing, ≥ 5 mm (group B); and lesion diameter of <5 mm (group C). The contrast ratio of the lesions on 3 consecutive phases of contrast-enhanced T2 FLAIR was measured, and the percentage increase of contrast-enhanced T2 FLAIR among the 3 groups was compared.RESULTS: In vitro, the maximal signal intensity was achieved in T2 FLAIR at one-eighth to one-half of the contrast concentration needed for maximal signal intensity in T1WI. In vivo, the mean contrast ratio values of metastases on contrast-enhanced T2 FLAIR for the 3 consecutive phases ranged from 63.64% to 83.05%. The percentage increase (PI) values of contrast-enhanced T2 FLAIR were as follows: PIA < PIB (P = .001) and PIA < PIC (P < .001). The degree of enhancement of brain metastases on contrast-enhanced T2 FLAIR was lower than on 3D brain volume imaging (P < .001) in group A, and higher than on 3D brain volume imaging (P < .001) in group C.CONCLUSIONS: Small or ring-enhancing metastases can be better visualized on delayed contrast-enhanced T2 FLAIR using a half-dose high-relaxivity contrast agent.BRAVObrain volume imagingCEcontrast-enhancedCRcontrast ratioGBCAgadolinium-based contrast agentsPIpercentage increase