Consecutive Acquisition of Time-resolved Contrast-enhanced MR Angiography and Perfusion MR Imaging with Added Dose of Gadolinium-based Contrast Agent Aids Diagnosis of Suspected Brain Metastasis

Abstract

Purpose: Time-resolved contrast-enhanced magnetic resonance (MR) angiography (TCMRA) and perfusion MR imaging (PWI) have been used to assess the hemodynamics of brain tumors. We assessed the feasibility and value of consecutive performance of these techniques to evaluate suspected brain metastasis following supplementary injection of gadolinium-based contrast medium.Methods: In 69 patients with suspected brain metastasis, we obtained precontrast MR images followed by TCMRA and postcontrast T 1 -weighted images after administration of 0.1 mmol/kg gadoteridol. Whenˆndings were negative or equivocal, we injected an additional 0.1-mmol/kg dose of gadoteridol and obtained PWI and second postcontrast T 1 -weighted images. We used a 3-point scale to grade perfusion maps and TCMRA and assessed whether these techniques added information to conventional MR imaging in the diŠerential diagnosis. We also evaluated whether the second contrast injection improved the conspicuity and/or number of enhancing lesions and used a 4-point scoring system to quantitatively analyze diagnostic yield of TCMRA and PWI.Results: We could assess tumor hemodynamics on PWI maps and TCMRA images in all 69 patients. In 14 cases (20z), PWI and/or TCMRA added information to conventional MRˆndings. After second injection of contrast medium, lesion conspicuity improved in 58 of the 69 cases (84z), and the number of detected lesions increased in 11 of 31 cases diagnosed with metastatic disease (36z). Quantitative analysis revealed TCMRA and PWI provided signiˆcant additional diagnostic information (Kruskal-Wallis test, Pº0.0001).Conclusion: Consecutive acquisition of TCMRA and PWI using supplementary contrast injection can facilitate diŠerential diagnosis of suspected brain metastasis and improve the number and conspicuity of detected lesions.