背景:60Hz的MR弹性成像(MRE)广泛用于分期肝纤维化。具有较低频率的MRE可以提供炎症生物标志物。
目的:在单次检查中,在30Hz和60Hz下建立实用的同时双频肝脏MRE协议,并验证30Hz下二次谐波的发生。
方法:回顾性。
方法:106名患者(48名女性,年龄:50.0±13.4岁)分为如下:队列1(15例慢性肝病[CLD]患者和25例健康志愿者)同时进行双频MRE。第2组(66例CLD患者)具有二次谐波MRE。
■3-T,单频或双频MRE在30赫兹和60赫兹。
结果:两个队列中的肝脏硬度(LS)通过两个独立的分析仪手动放置的体积ROI进行评估。图像质量由三个独立的阅读器以4分制进行评估(0-3:无/失败,公平,中度,优秀)基于1/3增量穿透的波传播深度。成功率来自非零质量分数的百分比。
方法:测量协议,偏见,LS的可重复性使用组内相关系数(ICC)进行评估,Bland-Altman阴谋,和重复性系数(RC)。使用Mann-WhitneyU检验来评估不同方法之间的图像质量差异。P值<0.05被认为具有统计学意义。
结果:队列1的成功率为97.5%,队列2的二次谐波MRE的成功率为91%。二次谐波和常规MRE在LS中显示出极好的一致性(所有ICC>0.90)。二次谐波图像的质量分数低于常规MRE(Z=-4.523)。
结论:与常规和二次谐波方法相比,同时双频有更好的图像质量,高成功率和内在共同注册的优势,而如果自定义波形不可用,则可以使用二次谐波方法。
方法:3技术效果:第一阶段。
BACKGROUND: MR elastography (
MRE) at 60 Hz is widely used for staging liver fibrosis.
MRE with lower frequencies may provide inflammation biomarkers.
OBJECTIVE: To establish a practical simultaneous dual-frequency liver
MRE protocol at both 30 Hz and 60 Hz during a single examination and validate the occurrence of second harmonic waves at 30 Hz.
METHODS: Retrospective.
METHODS: One hundred six patients (48 females, age: 50.0 ± 13.4 years) were divided as follows: Cohort One (15 patients with chronic liver disease [CLD] and 25 healthy volunteers) with simultaneous dual-frequency MRE. Cohort Two (66 patients with CLD) with second harmonic
MRE.
UNASSIGNED: 3-T, single- or dual-frequency
MRE at 30 Hz and 60 Hz.
RESULTS: Liver stiffness (LS) in both cohorts was evaluated with manually placed volumetric ROIs by two independent analyzers. Image quality was assessed by three independent readers on a 4-point scale (0-3: none/failed, fair, moderate, excellent) based on the depth of wave propagation with 1/3 incremental penetration. The success rate was derived from the percentage of nonzero quality scores.
METHODS: Measurement agreement, bias, and repeatability of LS were assessed using intraclass correlation coefficients (ICCs), Bland-Altman plots, and repeatability coefficient (RC). Mann-Whitney U tests were used to evaluate the differences in image quality between different methods. A P-value <0.05 was considered statistically significant.
RESULTS: Success rate was 97.5% in Cohort One and 91% success rate for the second harmonic MRE in Cohort Two. The second harmonic and conventional MRE showed excellent agreement in LS (all ICCs >0.90). The quality scores for the second harmonic wave images were lower than those from the conventional MRE (Z = -4.523).
CONCLUSIONS: Compared with conventional and second harmonic methods, simultaneous dual-frequency had better image quality, high success rate and the advantage of intrinsic co-registration, while the second harmonic method can be an alternative if custom waveform is not available.
METHODS: 3 TECHNICAL EFFICACY: Stage 1.