Kaltenbach Benjamin, Roman Andrei, Polkowski Christoph, Gruber-Rouh Tatjana, Bauer Ralf W, Hammerstingl Renate, Vogl Thomas J, Zangos Stephan
Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt am Main, Germany.
Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt am Main, Germany.
Eur J Radiol. 2017 Jan;86:26-32. doi: 10.1016/j.ejrad.2016.11.003. Epub 2016 Nov 3.
To compare free-breathing radial VIBE with moderate undersampling (us-radial-VIBE) with a standard breathhold T1-weighted volumetric interpolated sequence (3D GRE VIBE) in patients unable to suspend respiration during dynamic liver examination.
23 consecutive patients underwent dynamic liver MR examination using the free-breathing us-radial-VIBE sequence as part of their oncologic follow-up. All patients were eligible for the free-breathing protocol due to severe respiratory artifacts at the planning or precontrast sequences. The us-radial-VIBE acquisitions were compared to the patientś last staging liver MRI including a standard breathhold 3D GRE VIBE. For an objective image evaluation, signal intensity (SI), image noise (IN), signal-to-noise ratio (SNR) and contrast-enhancement ratio (CER) were compared. Representative image quality parameters, including typical artifacts were independently, retrospectively and blindly scored by four readers.
Us-radial-VIBE had significant lower SNR (p<0.0001) and higher IN (p<0.0001), whereas SI did not differ (p=0.62). Temporal resolution assessed with CER in the arterial phase showed higher values for us-radial-VIBE (p=0.028). Subjective image quality parameters received generally slightly higher scores for 3D GRE VIBE. In a smaller subgroup comprising patients with severe respiratory artifacts also at reference breathhold 3D GRE VIBE examination, us-radial-VIBE showed significantly higher image quality scores. Furthermore, there were generally more severe respiratory artifacts in 3D GRE VIBE, whereas streaking was characteristic in almost all us-radial-VIBE acquisitions but did not affect diagnostic validity.
Free-breathing dynamic liver imaging using us-radial-VIBE delivers accurate temporal resolution, low motion artifact susceptibility and good image quality and represents a promising alternative in patients unable to suspend respiration.
在动态肝脏检查中无法屏气的患者中，比较自由呼吸下的中度欠采样径向VIBE序列（us-radial-VIBE）与标准屏气T1加权容积内插序列（3D GRE VIBE）。
23例连续患者在肿瘤随访过程中接受了使用自由呼吸us-radial-VIBE序列的动态肝脏磁共振检查。由于在规划或对比前序列中存在严重的呼吸伪影，所有患者均符合自由呼吸方案的条件。将us-radial-VIBE采集的图像与患者最后一次分期肝脏MRI（包括标准屏气3D GRE VIBE）进行比较。为了进行客观的图像评估，比较了信号强度（SI）、图像噪声（IN）、信噪比（SNR）和对比增强率（CER）。由四位读者独立、回顾性且盲法对包括典型伪影在内的代表性图像质量参数进行评分。
us-radial-VIBE的SNR显著较低（p<0.0001），IN较高（p<0.0001），而SI无差异（p=0.62）。在动脉期用CER评估的时间分辨率显示us-radial-VIBE的值更高（p=0.028）。主观图像质量参数方面，3D GRE VIBE的得分总体略高。在一个较小的亚组中，包括在参考屏气3D GRE VIBE检查中也存在严重呼吸伪影的患者，us-radial-VIBE显示出显著更高的图像质量得分。此外，3D GRE VIBE中通常存在更严重的呼吸伪影，而在几乎所有us-radial-VIBE采集中条纹是其特征，但不影响诊断有效性。
使用us-radial-VIBE进行自由呼吸动态肝脏成像可提供准确的时间分辨率、低运动伪影敏感性和良好的图像质量，是无法屏气患者的一种有前景的替代方法。
