低场磁共振FLAIR序列对脑脊液内钆剂浓度检出的实验研究

 目的 探讨低场磁共振液体衰减反转恢复序列T2WI对人工脑脊液(cerebral spinal fluid,CSF)内钆浓度的识别水平,为临床应用提供依据.方法 采用浓度0～8 mmol/L的Gd-DTPA人工CSF溶液模拟CSF内不同的强化水平,新鲜熟蛋清模拟正常脑实质.使用0.35T机型,对样本分别行SE序列T1WI和快速FLAIR序列T2WI扫描,测算出各被检样本与参照样本间的对比噪声比(contrast-to-noise ratios,CNR),比较两种成像序列所能检出的最低钆剂浓度.结果 FLAIR序列T2WI所能识别的最低钆剂浓度为0.0078 mmol/L,比SE序列T1WI约低10倍;当样本内钆剂浓度超过0. 8 mmol/L时,FLAIR序列T2WI的检出能力不及SE序列T1WI.结论 低场磁共振FLAIR序列T2WI对人工CSF内低浓度钆剂的检出能力明显优于其SE序列T1WI.

Detection of gadolinium concentration in simulated cerebral spinal fluid on fluid-attenuated inversion recovery sequence at low field MR imaging unit: an in vitro investigation

Objective To evaluate the ability of T2 -weighted fluid- attenuated inversion recovery （FLAIR） MR images to detect gadolinium concentrations in artificial cerebral spinal fluid （CSF） in an in vitro study at low field MRI. Methods Different en- hancement in CSF was simulated with mixtures of artificial CSF and gadolinium chelate ranging from 0 mmol/L to 8 mmol/L Fresh hard - boiled egg white was used to simulate normal cerebral parenchyma. T2 - weighted turbo - FLAIR and T1 - weighted spin - echo （SE） MR imaging of these phantoms was performed on a 0.35 -T MR system. The contrast -to -noise ratios （CNRs） between the different gadolinium chelate artificial CSF mixture and hard - boiled egg white were measured and compared on both images. Results The gadolinium concentration that can be detected on T2 - weighted FLAIR image was 0. 0078 mmol/L, which was ten - fold lower than that on T1 - weighted SE image. T2 - weighted FLAIR image was not as effective as T1 - weighted SE image in revealing gadolini- um when its concentration was over 0.8 mmol/L. Conclusion T2 - weighted FLAIR imaging is obviously superior to T1 - weighted SE imaging in demonstrating low concentrations of gadolinium in artificial CSF in a low - field MR system.