腹部MRI检查“4+2+1”方案初步研究

The Initial Research of MRI Sequences of Plan 4+2+1 in Abdomen Examination

目的探索优化的腹部MRI检查方法。方法对117例随机患者用"4+2+1"方案进行腹部MRI检查,检查前空腹、口服等渗甘露醇溶液、肌注654-2,平扫采用快速扰相梯度回波序列(fast spoiled gradient echo,FSPGR)、改良的快速自旋回波序列(fast spin echo,FSE-XL)、真稳态进动快速成像序列(fast imaging employing steady-state acquisition,FIESTA)和弥散加权平面回波序列(diffusion-weighted echo planar imaging,DW EPI)4个序列,其中FIESTA序列除横轴位外加扫冠状位和矢状位2个体位,增强扫描采用肝脏容积超快速三维成像序列(liver acquisition with volume acceleration,LAVA)。结果FSPGR及FSE-XL对腹部实性脏器显示好,对胃肠道结构显示差;FIESTA对胃肠道及肠系膜结构显示清晰,对实性脏器病灶显示差;DW EPI对恶性肿瘤和组织缺血敏感,解剖细节分辨力低下;LAVA增强能反映组织器官血供特点,揭示病灶与血管的解剖关系。结论腹部MRI"4+2+1"方案包含的扫描序列和体位相互取长补短,形成了科学、高效的组合,应用这一组合既能得到高质量图像,又能准确反映病灶部位和信号特征,为定性诊断提供有力支持;FIESTA在胰十二指肠区和胃肠道病变诊断方面具有明显优势。

Objective To discuss the plan of promoting the imaging quality of magnetic resonance imaging（MRI） in the diagnosis of abdomen disease with 1.5T MR scanner.Methods 117 patients with abdomen disease were randomly selected to have MRI examination with 1.5T MR scanner using 4＋2＋1 sequences.Preparation before examination included empty stomach,5% mannitol solution taken orally and 654-2 intramuscular injection.The 4＋2＋1 sequences included 4 conventional sequences：Fast SPoiled Gradient Echo（FSPGR）,Fast Spin Echo（FSE-XL）,Fast Imaging Employing STeady-state Acquisition（FIESTA） and Diffusion-Weighted Echo Planar Imaging（DW EPI）,2 supernumerary FIESTA sequences in coronal and sagittal,and 1 contrast enhancement sequences using Liver Acquisition with Volume Acceleration（LAVA）.Results Quality analysis demonstrated that FSPGR and FSE-XL had highest image quality in abdomen parenchymatous organ lesions but bad image quality in gastrointestinal tract architecture;FIESTA had highest image quality in gastrointestinal tract and mesentery architecture but bad image quality in abdomen parenchimatous organ lesions;DWI EPI had high sensibility in malignant tumor and ischemia lesions but bad hisodefiniting power;LAVA could reflect a fine status of affection blood-supply and the feature of enhancement.Conclusion The 4＋2＋1 sequence MRI examination can provide not only high image quality but also accurate location and characteristic signals in abdomen parenchimatous organ lesions.Sequence FIESTA had obvious advantage in the diagnosis of pancreas-duodenum and gastrointestinal lesions.So this examination plan 4＋2＋1 deserved further application.