RT Journal Article
SR Electronic
T1 PC VIPR: A High-Speed 3D Phase-Contrast Method for Flow Quantification and High-Resolution Angiography
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 743
OP 749
VO 26
IS 4
A1 Tianliang Gu
A1 Frank R. Korosec
A1 Walter F. Block
A1 Sean B. Fain
A1 Quill Turk
A1 Darren Lum
A1 Yong Zhou
A1 Thomas M. Grist
A1 Victor Haughton
A1 Charles A. Mistretta
YR 2005
UL http://www.ajnr.org/content/26/4/743.abstract
AB BACKGROUND AND PURPOSE: Three-dimensional phase-contrast (3DPC) is limited by long imaging times, limited coverage, flow artifacts, and the need to perform multiple additional 2D examinations (2DPC) to measure flow. A highly undersampled 3D radial acquisition (isotropic-voxel radial projection imaging [PCVIPR]) makes it possible to increase the product of volume coverage and spatial resolution by a factor of 30 for the same imaging time as conventional Cartesian 3DPC. This provides anatomic information over a large volume with high isotropic resolution and permits retrospective measurement of average flow rates throughout the volume.METHODS: PCVIPR acquires a reference and three flow-encoded acquisitions for each VIPR projection. Complex difference images were formed by combining information from all flow directions. Following retrospective definition of planes perpendicular to selected vessels, volume flow rates were determined by using phase-difference information. The accuracy of average flow measurement was investigated in a phantom and in six volunteers. Anatomic PCVIPR images acquired in three patients and three volunteers by using a 3843 matrix were compared with conventional Cartesian 3DPC.RESULTS: The flow validation produced R2 = 0.99 in vitro and R2 = 0.97 in vivo. PCVIPR produced minimal streak and pulsatile flow artifacts. PCVIPR produced far higher resolution and volume coverage in comparable imaging times. The highest acceleration factors relative to 3DPC were achieved by using gadolinium-contrast material. Ultimately, acceleration factors are limited by signal-to-noise ratio.CONCLUSION: PCVIPR rapidly provides isotropic high-resolution angiographic images and permits retrospective measurement of average flow rate throughout the volume without the need to prescribe multiple 2D acquisition planes.