HighlY constrained backPRojection (HYPR) for Ultrafast Undersampled MRI

用于超快欠采样 MRI 的高度约束反投影 (HYPR)

• 批准号: 7362406
• 负责人: Charles A. Mistretta
• 金额: $ 17.64万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7362406
• 关键词: A-factor (Streptomyces); Algorithms; Angiography; Back; Behavior; Blur; Carotid Arteries; Cerebrum; Computer Simulation; Condition; Contracts; Data Set; Derivation procedure; Diffusion; Diffusion Magnetic Resonance Imaging; Dose; Equation; Evaluation; Future; Generations; Grant; Hour; Hybrids; Image; Imaging Techniques; Individual; Magnetic Resonance Imaging; Maps; Measurement; Measures; Methods; Morphologic artifacts; Motion; Numbers; Patients; Performance; Perfusion; Phase; Process; Property; Protocols documentation; Radial; Rate; Relative (related person); Resolution; Sampling; Scanning; Series; Simulate; Slice; Standards of Weights and Measures; Stenosis; Techniques; Time; Tornadoes; Venous Malformation; Work; X-Ray Computed Tomography; base; clinical application; cohort; concept; in vivo; pressure; reconstruction; research study; simulation; size; validation studies

DESCRIPTION (provided by applicant): During the past nine years our group has investigated various forms of k-space and temporal undersampling relative to the Nyquist Theorem for faster acquisitions in challenging MR imaging applications, particularly time resolved, high resolution contrast-enhanced angiography. Using 3D TRICKS, a temporal undersampling factor of 3 was achieved to provide time resolved 3D MR angiograms. Later, in-plane radially undersampled acquisitions were developed for acquiring angiograms with angular undersampling factors of 6. The combination of these two techniques in PR TRICKS resulted in undersampling factors of 18. Undersampling was extended to a truly 3D radial trajectory with VIPR, where typical undersampling factors of 50 can be used without significant artifacts in certain applications. In addition, VIPR has been combined with phase contrast imaging to permit 3D flow measurements across a large volume enabling the derivation of pressure gradients in small vessels. Recently, we developed the concept for an approximate non-iterative reconstruction technique called HYPR (HighlY constrained back PRojection) to further increase the permissible undersampling of temporally evolving acquisitions by another large factor that depends on the sparsity of the data set and the degree of spatio- temporal correlation between the serial images. Preliminary results have produced undersampling factors between 100 and 300 for contrast-enhanced angiography. A factor of nearly 1000 was achieved with adequate SNR in a 4 minute 3843 time-resolved phase contrast examination that would have required 39 hours using conventional Cartesian phase encoding methods. The technique was also used to achieve a factor of ten dose reduction in X-ray CT perfusion and can be generalized to other image series applications such as MR diffusion tensor imaging where the technique has simulated a factor of 15 undersampling in a 2D implementation using a series of images having different diffusion encoding directions. A large number of other potential applications that are not proposed here will benefit from a better understanding of the proposed algorithm and its potential limitations. HYPR provides unique SNR behavior by transferring the SNR obtained in a long composite image into individual time frames. The duration of this composite image must be adjusted for each clinical application so that spatial blurring and waveform distortion can be minimized. This depends on sparsity and spatio-temporal correlation conditions. We propose to investigate the basic properties of HYPR using computer simulations and phantoms and to conduct three preliminary patient studies to establish protocols to be used in future validation studies. This proposal focuses on the evaluation of cerebral AVMs using PR HYPR TRICKS and HYPR VIPR and the measurement of pressure gradients across stenotic carotid arteries.

描述（由申请人提供）：在过去的九年里，我们的团队研究了与奈奎斯特定理相关的各种形式的k空间和时间不足采样，以便在具有挑战性的MR成像应用中更快地获取数据，特别是时间分辨率、高分辨率对比度增强血管造影。使用3D TRICKS，实现了3的时间欠采样因子，以提供时间分辨率的3D MR血管成像。后来，平面内径向欠采样采集被开发用于获取血管图像，角度欠采样因子为6。在PR TRICKS中，这两种技术的结合导致欠采样因子为18。使用VIPR，欠采样扩展到真正的3D径向轨迹，在某些应用中，典型的欠采样因子为50，不会产生明显的伪影。此外，VIPR与相衬成像相结合，可以在大体积范围内进行3D流量测量，从而推导出小容器中的压力梯度。

项目成果

Ultrashort TE spectroscopic imaging (UTESI) using complex highly-constrained backprojection with local reconstruction (HYPR LR).

使用复杂的高度约束反投影和局部重建 (HYPR LR) 的超短 TE 光谱成像 (UTESI)。

• DOI: 10.1002/mrm.21986
• 发表时间: 2009
• 期刊: Magnetic resonance in medicine
• 影响因子: 3.3
• 作者: Wang,Kang;Du,Jiang;O'Halloran,Rafael;Fain,Sean;Kecskemeti,Steven;Wieben,Oliver;Johnson,KevinM;Mistretta,Charles
• 通讯作者: Mistretta,Charles