Flow imaging using balanced phase contrast steady state free precession magnetic resonance imaging

US6806709B2 · kind B2 · utility

Assignee

• The Board of Trustees of the Leland Stanford Junior University · US

Inventors

• Michael Markl · Chicago, US
• Norbert J. Pelc · Wauwatosa, US
• Marcus T. Alley · Palo Alto, US

Key dates

• Filing date: Dec 11, 2002
• Grant date: Oct 19, 2004
• Expiry date: Dec 11, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/56316
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A novel technique for velocity measurements (PC-SSFP) is disclosed that combines CINE Phase Contrast (PC) MRI and balanced Steady State Free Precession (SSFP) imaging. Flow encoding is performed without the introduction of additional velocity encoding gradients in order to permit data acquisition with short TR comparable to repetition times of typical SSFP imaging sequences. Sensitivity to through plane velocities is instead established by inverting (i.e. negating) all gradients along the slice select direction. Velocity sensitivity (venc) can be adjusted by altering the first moments of the slice select gradients. Disturbances of the SSFP steady state are avoided by acquiring different flow echoes in consecutively (i.e. sequentially) executed scans, each over several cardiac cycles, using separate steady state preparation periods. Comparison of phantom measurements with those from established 2D-CINE-PC MRI excellent correlation between both modalities. Results of volunteer examinations exhibit advantages of PC-SSFP, which include the intrinsic high signal to noise ratio (SNR) of balanced SSFP and consequently low phase noise in measured velocities. An additional benefit of PC-SSF…