From the *Center for Advanced Imaging Innovation and Research (CAI2R); and †Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, NY.
Invest Radiol. 2017 Oct;52(10):583-589. doi: 10.1097/RLI.0000000000000375.
The aim of this study was to assess the applicability of Dixon radial volumetric encoding (Dixon-RAVE) for comprehensive dynamic contrast-enhanced 3D magnetic resonance imaging (MRI) of the breast using a combination of radial sampling, model-based fat/water separation, compressed sensing, and parallel imaging.
In this Health Insurance Portability and Accountability Act-compliant prospective study, 24 consecutive patients underwent bilateral breast MRI, including both conventional fat-suppressed and non-fat-suppressed precontrast T1-weighted volumetric interpolated breath-hold examination (VIBE). Afterward, 1 continuous Dixon-RAVE scan was performed with the proposed approach while the contrast agent was injected. This scan was immediately followed by the acquisition of 4 conventional fat-saturated VIBE scans. From the comprehensive Dixon-RAVE data set, different image contrasts were reconstructed that are comparable to the separate conventional VIBE scans.Two radiologists independently rated image quality, conspicuity of fibroglandular tissue from fat (FG), and degree of fat suppression (FS) on a 5-point Likert-type scale for the following 3 comparisons: precontrast fat-suppressed (pre-FS), precontrast non-fat-suppressed (pre-NFS), and dynamic fat-suppressed (dyn-FS) images.
When scores were averaged over readers, Dixon-RAVE achieved significantly higher (P < 0.001) degree of fat suppression compared with VIBE, for both pre-FS (4.25 vs 3.67) and dyn-FS (4.10 vs 3.46) images. Although Dixon-RAVE had lower image quality score compared with VIBE for the pre-FS (3.56 vs 3.67, P = 0.490), the pre-NFS (3.54 vs 3.88, P = 0.009), and the dyn-FS images (3.06 vs 3.67, P < 0.001), acceptable or better diagnostic quality was achieved (score ≥ 3). The FG score for Dixon-RAVE in comparison to VIBE was significantly higher for the pre-FS image (4.23 vs 3.85, P = 0.044), lower for the pre-NFS image (3.98 vs 4.25, P = 0.054), and higher for the dynamic fat-suppressed image (3.90 vs 3.85, P = 0.845).
Dixon-RAVE can serve as a one-stop-shop approach for comprehensive T1-weighted breast MRI with diagnostic image quality, high spatiotemporal resolution, reduced overall scan time, and improved fat suppression compared with conventional imaging.
本研究旨在评估 Dixon 径向容积编码(Dixon-RAVE)在使用径向采样、基于模型的脂肪/水分离、压缩感知和并行成像相结合的综合动态对比增强 3D 磁共振成像(MRI)中的适用性。
这项符合《健康保险流通与责任法案》的前瞻性研究纳入了 24 例连续患者,他们接受了双侧乳腺 MRI 检查,包括常规脂肪抑制和非脂肪抑制的对比前 T1 加权容积内插屏气检查(VIBE)。之后,在注射造影剂的同时,采用提出的方法进行连续 Dixon-RAVE 扫描。该扫描立即跟随 4 个常规脂肪饱和 VIBE 扫描。从全面的 Dixon-RAVE 数据集,重建了不同的图像对比度,与单独的常规 VIBE 扫描相当。两位放射科医生独立对以下 3 种比较的图像质量、纤维腺体组织与脂肪的对比(FG)和脂肪抑制程度(FS)进行了 5 分李克特量表评分:对比前脂肪抑制(pre-FS)、对比前非脂肪抑制(pre-NFS)和动态脂肪抑制(dyn-FS)图像。
当评分在读者之间平均时,与 VIBE 相比,Dixon-RAVE 实现了显著更高(P<0.001)的脂肪抑制程度,无论是在 pre-FS(4.25 与 3.67)还是 dyn-FS(4.10 与 3.46)图像中。尽管 Dixon-RAVE 与 VIBE 相比,pre-FS 图像的图像质量评分较低(3.56 与 3.67,P=0.490),pre-NFS(3.54 与 3.88,P=0.009)和 dyn-FS 图像(3.06 与 3.67,P<0.001),但仍获得了可接受或更好的诊断质量(评分≥3)。与 VIBE 相比,Dixon-RAVE 的 FG 评分在 pre-FS 图像中更高(4.23 与 3.85,P=0.044),在 pre-NFS 图像中更低(3.98 与 4.25,P=0.054),在动态脂肪抑制图像中更高(3.90 与 3.85,P=0.845)。
与传统成像相比,Dixon-RAVE 可以作为一种一站式综合 T1 加权乳腺 MRI 方法,具有诊断图像质量、高时空分辨率、缩短整体扫描时间和改善脂肪抑制等优点。