LAVA-Flex序列结合膈肌导航技术在肝脏T1WI中的应用

Application of diaphragmatic navigation technology combined with LAVA-Flex sequences on liver T1WI imaging

目的:探讨LAVA-Flex序列结合膈肌导航技术在肝脏T1WI检查中的应用价值。方法:选取63例行肝脏MRI检查的患者,行常规LAVA-Flex序列屏气扫描,和LAVA-Flex序列结合膈肌导航技术自由呼吸扫描,由两名5年以上腹部MRI诊断经验的医师对两组图像从肝脏边缘的锐利度、肝脏血管的清晰度、图像伪影、脂肪抑制效果及整体图像质量5个方面进行主观评分,在肝门层面测量肝右叶及脾脏图像的信号强度(SI)和噪声值(SD),计算肝脏信噪比(SNR)和肝脾对比噪声比(CNR),比较两组间图像差异。结果:屏气序列和自由呼吸序列主观评分分别为4.48±0.68、4.54±0.65(P=0.694),差异无统计学意义;自由呼吸序列的肝脏SNR及肝脾CNR分别为41.80±7.75、5.74±3.48,屏气序列的肝脏SNR及肝脾CNR分别为27.9±9.62、4.16±3.77,自由呼吸序列的肝脏SNR及肝脾CNR均高于屏气组(P<0.05)。结论:LAVA-Flex序列结合膈肌导航技术,在自由呼吸状态下可以得到高质量的影像,对于屏气欠佳或无法屏气患者提供了较好的解决方案。

Objective:To investigate the value of diaphragmatic navigation technology combined with liver acceleration volume acquisition-flexible (LAVA-Flex) serial scanning in liver T1WI examination.Method:Sixty-three patients were selected as study subjects.The conventional LAVA-Flex sequence was used for breath-holding scanning(recorded as the breath-holding group),and the diaphragm navigation technology combined with the LAVA-Flex sequence for free breathing scanning(recorded as the free breathing group).Two physicians with more than five years of experience in abdominal system diagnosis scored the images of the two groups from four aspects:sharpness of liver edge,articulation of liver blood vessels,image artifacts,and fat inhibition effect.ROI was selected in the homogeneous tissue on right liver lobe and spleen at the hilar level.The signal intensity(SI) and standard deviation(SD),SD of the liver and spleen were measured.The signal to noise ratio(SNR) and the contrast to noise ratio (CNR) were calculated,and the image quality of the two sequences was compared.Results:The subjective scores of the breath-holding group and the free breathing group were 4.48±0.68 and 4.54±0.65,respectively(P=0.694),with no statistical significance.The SNR and CNR of the free breathing group were 41.80±7.75 and 5.74±3.48.The SNR and CNR of the breath-holding group were 27.9±9.62 and 4.16±3.77.The SNR and CNR of free breathing group were higher than the value of the breath-holding group (P<0.05).Conclusion:The diaphragmatic navigation technology combined with the LAVA-Flex sequence can be used for abdominal MRI examination,and images that meet the diagnostic requirements are obtained in the state of free breathing,providing a better solution for patients who are unable to hold breath.