Spin locked balanced steady-state free precession (slSSFP) with off-resonance spin locked pulses interleaved with imaging gradients

US8148982B2 · kind B2 · utility

Assignee

• The Trustees of the University of Pennsylvania · US

Inventors

• Walter Witschey · Philadelphia, US
• Mark A. Elliott · Calgary, CA
• Ari Borthakur · Philadelphia, US
• Ravinder Reddy · Conshohocken, US

Key dates

• Filing date: Apr 20, 2009
• Grant date: Apr 3, 2012
• Expiry date: Apr 5, 2030

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/5614
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A spin locked balanced steady-state free precession (slSSFP) pulse sequence combines a balanced gradient echo acquisition with an off-resonance spin lock pulse for fast MRI. The transient and steady-state magnetization trajectory is solved numerically using the Bloch equations and is shown to be similar to balanced steady-state free precession (bSSFP) for a range of T2/T1 and flip angles, although the slSSFP steady-state could be maintained with considerably lower RF power. In both simulations and brain scans performed at 7T, slSSFP is shown to exhibit similar contrast and SNR efficiency to bSSFP, but with significantly lower power.