Balanced UTE-SSFP for 19F MR imaging of complex spectra.

Abstract

PURPOSE:

A novel technique for highly sensitive detection of multiresonant fluorine imaging agents was designed and tested with the use of dual-frequency 19F/1H ultrashort echo times (UTE) sampled with a balanced steady-state free precession (SSFP) pulse sequence and three-dimensional (3D) radial readout.

METHODS:

Feasibility of 3D radial balanced UTE-SSFP imaging was demonstrated for a phantom comprising liquid perfluorooctyl bromide (PFOB). Sensitivity of the pulse sequence was measured and compared with other sequences imaging the PFOB (CF2 )6 line group including UTE radial gradient-echo (GRE) at α = 30°, as well as Cartesian GRE, balanced SSFP, and fast spin-echo (FSE). The PFOB CF3 peak was also sampled with FSE.

RESULTS:

The proposed balanced UTE-SSFP technique exhibited a relative detection sensitivity of 51 μmolPFOB(-1) min(-1/2) (α = 30°), at least twice that of other sequence types with either 3D radial (UTE GRE: 20 μmolPFOB(-1) min(-1/2) ) or Cartesian k-space filling (GRE: 12 μmolPFOB(-1) min(-1/2) ; FSE: 16 μmolPFOB(-1) min(-1/2) ; balanced SSFP: 23 μmolPFOB(-1) min(-1/2) ). In vivo imaging of angiogenesis-targeted PFOB nanoparticles was demonstrated in a rabbit model of cancer on a clinical 3 Tesla scanner.

CONCLUSION:

A new dual 19F/1H balanced UTE-SSFP sequence manifests high SNR, with detection sensitivity more than two-fold better than traditional techniques, and alleviates imaging problems caused by dephasing in complex spectra.

• Authors: Matthew J Goette, Jochen Keupp, Jürgen Rahmer, Gregory M Lanza, Samuel A Wickline, Shelton D Caruthers
• Journal: Magnetic resonance in medicine (Magn Reson Med) Vol. 74 Issue 2 Pg. 537-43 (Aug 2015) ISSN: 1522-2594 [Electronic] United States
• PMID: 25163853 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: © 2014 Wiley Periodicals, Inc.

Topics

• Algorithms
• Animals
• Feasibility Studies
• Female
• Fluorine-19 Magnetic Resonance Imaging (instrumentation, methods)
• Humans
• Image Enhancement (methods)
• Image Interpretation, Computer-Assisted (methods)
• Male
• Neoplasms, Experimental (pathology)
• Phantoms, Imaging
• Rabbits
• Reproducibility of Results
• Sensitivity and Specificity
• Signal Processing, Computer-Assisted