Evaluation of Regional Variability and Measurement Reproducibility of Intravoxel Incoherent Motion Diffusion Weighted Imaging Using a Cardiac Stationary Phase Based ECG Trigger Method.

Zhiming Xiang,Jianke Liang,Guijin Li,Xiaolei Zhu,Xu Yan,Zhu Ai

doi:10.1155/2018/4604218

Zhiming Xiang, Jianke Liang + Show 4 more

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https://doi.org/10.1155/2018/4604218

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Abstract

Purpose To evaluate the performance of an optimized ECG trigger diffusion weighted imaging (DWI) sequence in liver and its application in liver disease. Materials and Methods Eighteen healthy volunteers underwent intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) scan of the liver twice in 1.5T MR scanner with signed informed consent approved by local ethic committees. A new method, called cardiac stationary phase based ECG trigger (CaspECG), and FB method were applied. The apparent diffusion coefficient (ADC) and the IVIM parameters, including pure diffusion coefficient (D), perfusion-related diffusion coefficient (D⁎), and perfusion fraction, (PF) were calculated, and then 18 region of interests were drawn on these parameter maps independently by two readers through whole hepatic lobe. The regional variability and reproducibility between two repeated scans were evaluated using interclass correlation coefficients (ICCs) and Bland-Altman plot, respectively, and compared between the CaspECG and FB methods. The signal-to-noise ratio (SNR) of DWI data was also evaluated. Result Compared to the FB method, the proposed CaspECG method showed significant higher SNRs in DWI data, lower regional variability between left and right hepatic lobes, and higher reproducibility of ADC, PF, D, and D⁎ between repeat scans [left lobe, limit of agreement (LOA) of Bland-Altman plot: 10.1%, 18.3%, 19.8%, and 59.2%; right lobe, LOA: 10.25%, 14.15%, 16.45%, and 39.45%]. D⁎ showed the worst reproducibility in all parameters. Conclusion The novel CaspECG method outperformed the FB method in compensating the cardiac motion induced artifacts in DWI data and generating more reliable quantitative parameters, with less regional variability and higher repeatability, especially in the left hepatic lobe.

Highlights

Diffusion weighted imaging (DWI) has been widely used in the diagnosis, prognosis, and evaluation of liver diseases [1,2,3,4]
The beginning of cardiac relative stationary states was set as the trigger delay time, and the time interval of the cardiac relative stationary was set as the sampling duration time (TR); the detailed times were set into the SS-EPI sequences for intravoxel incoherent motion (IVIM)-DWI protocol
The signal-to-noise ratio (SNR) of DWI data decrease as b value increases, except for b = 0 sec/mm2, where lower average number was applied (3-scan-trace mode were used for nonzero b value)

Summary

Introduction

Diffusion weighted imaging (DWI) has been widely used in the diagnosis, prognosis, and evaluation of liver diseases [1,2,3,4]. The apparent diffusion coefficient (ADC) which used traditional mono-exponential model could not fully account for the microcirculation and perfusion effect of liver tissue [5, 6]. Studies have shown that IVIM is helpful in clinical diagnosis and treatment assessment of liver disease [9,10,11,12,13,14,15]. Many earlier studies have reported that physiological motion, such as respiratory and cardiac, may cause signal loss in the liver DWI image and measurement

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Conclusion