Measurement of spin-lattice relaxation times with FLASH for dynamic MRI of the breast.

Using a variable flip angle gradient refocused imaging technique, dynamic quantitative T1 relaxation maps acquired before and after the administration of a gadolinium contrast bolus enable the concentration-time curve of the paramagnetic agent in breast tissue to be calculated. This imaging technique has the aim of improving the diagnostic accuracy of MR mammography. Measurements with phantoms of calibrated T1 values have been carried out to investigate the accuracy of the method, with particular reference to errors caused by incomplete spoiling of residual transverse magnetization and inaccurate radio frequency (RF) flip-angle settings. A clinical example is presented. The method has potential use for any patient study which necessitates rapid quantitation of changing in vivo T1 values as a result of contrast agent injection.