运动解析压缩感知重建的自由呼吸XD-VIBE在肝脏富血供病变动态增强MRI中的应用

Application of free-breathing extra-dimensional VIBE with motion-resolved compressed sensing reconstruction in dynamic enhanced MRI of hypervascular liver lesions

目的:评价运动解析压缩感知重建的自由呼吸额外维度VIBE(XD-VIBE)在肝脏富血供病变(HLLs)动态增强MRI中的应用价值。方法:21例入组患者7天内均行肝脏常规屏气VIBE(BH-VIBE)多期增强和自由呼吸XD-VIBE连续采集(184 s)。三名高年资医师采用5分法评估图像质量,并记录动脉期观察到的直径>5 mm的HLLs。比较两种序列之间和各序列四期图像质量及两种序列对HLLs的检出能力。结果:XD-VIBE与BH-VIBE增强后三期图像质量差异均无统计学意义(P>0.05),但XD-VIBE平扫图像质量较BH-VIBE差(P<0.05)。XD-VIBE中,平扫图像质量低于增强后三期(P均<0.05);动脉期总体图像质量、肝边缘锐度较门静脉期差(P均<0.05);门静脉期呼吸伪影最少(P均<0.05);动脉期、门静脉期及平衡期肿块显著性相当(均P>0.05)。无论大小及良恶性,XD-VIBE和BH-VIBE检出HLLs能力相当(P均>0.05)。结论:自由呼吸XD-VIBE可提供与常规BH-VIBE相当的增强后图像质量和HLLs检出效能。

Objective:The purpose of this study was to evaluate the value of free-breathing eXtra-Dimensional VIBE(XD-VIBE)with motion-resolved compressed sensing reconstruction in dynamic enhancement MRI of hypervascular liver lesions(HLLs).Methods:21 recruited patients underwent both conventional breath-holding VIBE(BH-VIBE)for multi-phases enhanced scan and free-breathing XD-VIBE for continuous acquisition(184s)within 7 days.Image quality was assessed by three senior radiologists using a 5-point scale and HLL lesions with diameter bigger than 5mm in the arterial phase were recorded.Image quality of the four phases between two sequences and within each sequence as well as detection rate of HLLs between two sequences were compared.Results:There was no significant difference between XD-VIBE and BH-VIBE for image quality in three contrast-enhanced phases(all P>0.05),whereas image quality of XD-VIBE was worse than that of BH-VIBE in non-enhanced phase(P<0.05).For XD-VIBE,the image quality of the non-enhanced phase was lower than that of the other three phases after enhancement(all P>0.05),the overall image quality and hepatic edge sharpness of the arterial phase were inferior to that of the portal venous phase(all P<0.05),the respiratory artifacts of the portal venous phase were the least(all P<0.05),and the lesion conspicuity in the arterial,portal venous,and equilibrium phases was comparable(all P>0.05).Whether large or small,benign or malignant,HLLs were equally capable of being detected by XD-VIBE and BH-VIBE(all P>0.05).Conclusion:Compared with conventional BH-VIBE,free breathing XD-VIBE improves comparable image quality in contrast-enhanced phases and detection performance for HLLs.