Variable flip angle-based fast three-dimensional T1 mapping for delayed gadolinium-enhanced MRI of cartilage of the knee: Need for B1 correction

Authors


Abstract

Delayed gadolinium-enhanced MRI of cartilage is a technique, which involves T1 mapping to identify changes in the structural integrity of cartilage associated with osteoarthritis. Currently, the gold standard is 2D inversion recovery turbo spin echo, which suffers from long acquisition times and limited coverage. Three-dimensional variable flip angle (VFA) is an alternate technique, which has been shown to be accurate when an estimate of T1 is available a priori. This study validates the variable flip angle method for delayed gadolinium-enhanced MRI of cartilage of the femoro-tibial knee cartilage. When amplitude of (excitation) radiofrequency field inhomogeneities were minimized using nonselective pulses and amplitude of (excitation) radiofrequency field correction using an additional acquisition of a amplitude of (excitation) radiofrequency field map, the accuracy of T1 measurements were improved, and slice-to-slice variations over the 3D volume were minimized. In conclusion, fast 3D T1 mapping using the variable flip angle method with amplitude of (excitation) radiofrequency field correction appears to be an efficient and accurate method for delayed gadolinium-enhanced MRI of cartilage of the knee. Magn Reson Med, 2011. © 2010 Wiley-Liss, Inc.

Ancillary