肾动脉：各向同性、高空间分辨率、三维径向相位对比的非增强磁共振血管造影。
Renal arteries: isotropic, high-spatial-resolution, unenhanced MR angiography with three-dimensional radial phase contrast.
机构信息
Department of Radiology, Cardiothoracic and MRI Divisions, University of Wisconsin, 600 Highland Ave, Madison, WI 53792-3252, USA.
出版信息
Radiology. 2011 Jan;258(1):254-60. doi: 10.1148/radiol.10100443. Epub 2010 Oct 27.
PURPOSE
To prospectively compare a new three-dimensional (3D) radial phase-contrast magnetic resonance (MR) angiographic method with contrast material-enhanced MR angiography for anatomic assessment of the renal arteries.
MATERIALS AND METHODS
An institutional review board approved this prospective HIPAA-compliant study. Informed consent was obtained. Twenty-seven subjects (mean age, 52.6 years ± 20.5 [standard deviation]) were imaged with respiratory-gated phase-contrast vastly undersampled isotropic projection reconstruction (VIPR) prior to contrast-enhanced MR angiographic acquisition with a 3.0-T clinical system. The imaging duration for phase-contrast VIPR was 10 minutes and provided magnitude and complex difference ("angiographic") images with 3D volumetric (320 mm) coverage and isotropic high spatial resolution (1.25 mm(3)). Quantitative analysis consisted of comparing vessel diameters between the two techniques. Qualitative assessment included evaluation of the phase-contrast VIPR and contrast-enhanced MR angiographic techniques for artifacts, noise, and image quality. Bland-Altman analysis was used for comparison of quantitative measurements, and the Wilcoxon signed rank test was used for comparison of qualitative scores.
RESULTS
Phase-contrast VIPR images were successfully acquired in all subjects. The vessel diameters measured with phase-contrast VIPR were slightly greater than those measured with contrast-enhanced MR angiography (mean bias = 0.09 mm). Differences in mean artifact, quality scores for the proximal renal arteries, and overall image quality scores between phase-contrast VIPR and contrast-enhanced MR angiographic techniques were not statistically significant (P = .31 and .29, .27 and .39, and .43 and .69 for readers 1 and 2, respectively). The quality scores for the segmental renal arteries were higher for phase-contrast VIPR than for contrast-enhanced MR angiography (P < .05). Although the noise scores were higher with phase-contrast VIPR than with contrast-enhanced MR angiography and were statistically significant (P < .05), the presence of noise did not interfere with the ability to interpret the images.
CONCLUSION
Isotropic, high-spatial-resolution, unenhanced MR angiography of the renal arteries is feasible with 3D radial undersampling.
目的
前瞻性比较一种新的三维（3D）径向相位对比磁共振（MR）血管造影方法与对比增强 MR 血管造影，以评估肾动脉的解剖结构。
材料与方法
本研究经机构审查委员会批准，并获得了知情同意。27 例受检者（平均年龄，52.6 岁±20.5[标准差]）在使用 3.0T 临床系统进行对比增强 MR 血管造影采集前，接受了呼吸门控相位对比大欠采样各向同性体素重建（VIPR）成像。相位对比 VIPR 的成像时间为 10 分钟，提供了具有 3D 容积（320mm）覆盖和高空间分辨率（1.25mm³）的幅度和复数差（“血管造影”）图像。定量分析包括比较两种技术的血管直径。定性评估包括评估相位对比 VIPR 和对比增强 MR 血管造影技术的伪影、噪声和图像质量。Bland-Altman 分析用于比较定量测量值，Wilcoxon 符号秩检验用于比较定性评分。
结果
所有受检者均成功获得相位对比 VIPR 图像。相位对比 VIPR 测量的血管直径略大于对比增强 MR 血管造影测量的血管直径（平均偏差=0.09mm）。相位对比 VIPR 和对比增强 MR 血管造影技术之间的平均伪影、近端肾动脉质量评分和整体图像质量评分差异无统计学意义（P=0.31 和 0.29、0.27 和 0.39、0.43 和 0.69，分别为两位读者）。相位对比 VIPR 的节段性肾动脉质量评分高于对比增强 MR 血管造影（P＜0.05）。虽然相位对比 VIPR 的噪声评分高于对比增强 MR 血管造影，且具有统计学意义（P＜0.05），但噪声的存在并不影响图像的解读能力。
结论
3D 径向欠采样可实现肾动脉的各向同性、高空间分辨率、非增强 MR 血管造影。
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