Time-Resolved MRA
Tuesday 21 April 2009
Room 313A 13:30-15:30


James C. Carr and Vivian S. Lee

13:30  270. Time Resolved Angiography: Past, Present, and Future
    Charles A. Mistretta1
University of Wisconsin
13:54 271. High Temporal and Spatial Resolution Time-Resolved 3D CE-MRA of the Hands and Feet
    Clifton R. Haider1, James F. Glockner1, Anthony W. Stanson1, Stephen J. Riederer1
Radiology, Mayo Clinic, Rochester, MN, USA
    High spatial resolution arterial-only frames are desired in time-resolved 3D CE-MRA of the hands and feet. However, the increased spatial undersampling used for acceleration generally causes a reduction in image quality. In this work dedicated eight- and twelve-element peripheral vascular coil arrays were developed to maintain high image quality for accelerations greater than an order of magnitude (>10x). Results demonstrate high diagnostic image quality for high spatial and temporal resolution, bilateral 3D CE-MRA of the hands and feet.


14:06 272. Highly Accelerated Contrast-Enhanced MR Angiography Using Ghost Imaging
    Robert R. Edelman1,2, Ioannis Koktzoglou1,2
Radiology, NorthShore University HealthSystem, Evanston, IL, USA; 2Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA

Ghost MRA represents a fundamentally new approach for vascular imaging with potential applications for both non-contrast and contrast-enhanced angiography (CE-MRA). The method involves the creation of a ghost image which displays the vasculature with little or no signal contribution from background tissues. We compared conventional subtraction CE-MRA with Ghost CE-MRA in a series of healthy subjects using comparable image acquisition parameters. We also tested the hypothesis that Ghost imaging enables the use of much higher parallel acceleration factors (up to 13) than are feasible with standard phased array coils using the conventional CE-MRA approach.

14:18 273. Radial Sliding Window Time Resolved MRA: Evaluation of Intrapulmonary Circulation Parameters in Pulmonary Arterial Hypertension
    John J. Sheehan1, Hyun Jeong2, Amir Davarpanah3, Cormac Farrelly1, Randall Ramsy1, Sanjiv Shah4, Tim Carroll2, James C. Carr1,3
Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA; 2Biomedical Engineering, Northwestern University, Chicago, IL, USA; 3Cardiovascular Imaging, Northwestern University, Chicago, IL, USA; 4Cardiology, Northwestern Memorial Hospital, Chicago, IL, USA
    Pulmonary arterial and venous transit times were measured by radial sliding window time-resolved MRA to calculate pulmonary blood volumes and correlated with ventricular volumetrics in patients with pulmonary arterial hypertension (PAH). Radial MRA allows high temporal resolution, free breathing MRA with good separation between arterial and venous phases. Intrapulmonary transit times (ITT) were prolonged in patients with PAH. ITT correlated directly with RVEDV/ESV, and inversely with RVEF. Radial MRA allows determination and separation of intrapulmonary transit times that are prolonged, and pulmonary blood volumes, which are raised in pulmonary arterial hypertension.


14:30 274. Contrast Enhanced MRA with Retrospective Selection of Acceleration Factor
    Bing Wu1, Richard Watts2, Anthony Butler1, Rick Millane1, Philip Bones1
Department of Electrical can Computer Engineering, University of Canterbury, Chirstchurch, New Zealand; 2Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand
    A new time resolved contrast enhanced MR angiography method is proposed, which allows the desired temporal resolution to be selected in post processing and hence achieves an optimal trade-off between temporal resolution and SNR. To further improve the reconstruction SNR, subtraction of the background signal is incorporated to achieve a much smaller object support constraint. The utility of the method is demonstrated using in vivo data sets obtained from a healthy volunteer.
14:42 275. MR Cerebral Angiography Using Arterial Spin Labeling for Dynamic Inflow Visualization and Vessel Selectivity
    Weiying Dai1,2, Philip M. Robson1,2, Ajit Shankaranarayanan3, David C. Alsop1,2
Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA; 2Radiology, Harvard Medical School, Boston, MA, USA; 3Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA
    Digital subtraction X-ray angiography (DSA) is a widely used technique for the characterization of cerebral vessels. While MRI and CT can, in principle, provide angiographic information that could replace the riskier DSA study, these techniques typically lack the vessel selectivity and temporal resolution of DSA. Here we present the use of arterial spin labeling methods combined with balanced-SSFP acquisition to provide an MR angiographic exam more similar to DSA.
14:54 276. Very Low Dose Time-Resolved MR Angiography
    Gerhard Laub1, Randall Kroeker2, Derek Lohan3, Paul Finn3
Siemens Medical Solutions USA, Los Angeles, CA, USA; 2Siemens Medical Solutions, Canada; 3David Geffen School of Medicine, UCLA
    In view of NSF, we tested the feasibility of performing very low dose time-resolved 3D MR angiography in 10 patients and compared with standard dose contrast-enhanced MRA.
15:06 277.

HYPR-L0:  a Hybrid Technique for CE MRA with Extreme Data Undersampling Factors


Julia V. Velikina1, Alexey A. Samsonov
1Medical Physics, University of Wisconsin - Madison, Madison, WI, USA

    We present a novel synergistic method for time-resolved image reconstruction from extremely undersampled data that utilizes independent acceleration mechanisms of non-Cartesian acquisition, parallel imaging, compressed sensing, and HYPR. The new technique is validated for applications to time-resolved contrast-enhanced angiography of the brain where it produces images with high spatial and temporal resolution and high SNR for the acceleration factors at which other reconstruction methods fail.


15:18 278. Nonenhanced 3D Breast MRA Using FBI and Time-SLIP
    Mitsue Miyazaki1,2, Pamera M. Otto3, Hitoshi Kanazawa4, Nobuyasu Ichinose4, Satoshi Sugiura4, Robert Anderson Anderson1
Toshiba Medical Research Institute, Vernon Hills, IL, USA; 2MRI, Toshiba Medical Systems Corp, Otawara, Tochigi, Japan; 3Radiology, University of Texas at San Antonio, San Antonio, TX, USA; 4MRI, Toshiba Medical Systems Corp., Otawara, Tochigi, Japan
    Breast Dynamic contrast-enhanced (DCE) MRA is becoming a standard examination tool for small lesion detection. This study presents an initial volunteer investigation of nonenhanced breast MRA using the Fresh Blood Imaging (FBI) and Time-Spatial Labeling Inversion Pulse (time-SLIP) sequences. FBI provides clear depiction of all vessels and time-SLIP provides time-course imaging of selective vessels branching from the mammary arteries.