Ambrose Huang MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To evaluate a new magnetic resonance (MR) sequence that enables the measurement of T1 relaxation times in the time frame of a single breath-hold for application to quantitative MR perfusion imaging. Methods and Materials: We assembled a phantom consisting of 20 bottles containing known concentrations of Gd-DTPA in water to achieve T1 values ranging from 5-2600 ms. We scanned the phantom using an inversion recovery STIR sequence (TR = 10000 msec and inversion times of 50 msec, 100 msec, 200 msec, 400 msec, ..., 1800 msec, and 2000 msec for a total of 12 samples) and a segmented k-space inversion recovery cine TrueFISP sequence (matrix 124´256, flip angle = 10°, TR = 2.9 msec, inversion times of 80 + i´90.5 msec for i = 0, 1, 2, ..., 31, with the effective inversion time interval of 90.5 msec resulting from 31 lines per segment, time between inversion pulses 6000 msec, total acquisition time 24 sec). For both the STIR and cine TrueFISP data sets, regions of interest were placed over each bottle, whose signal intensity was then plotted against inversion time. These data were then fit to a three-parameter inversion recovery equation using the Levenberg-Marquardt method to obtain the T1 value of each bottle. Results: There was excellent agreement between the T1 values obtained from the STIR sequence as compared to those obtained from the inversion recovery TrueFISP sequence for values ranging from 87-1804 msec (equation of regression line: y = 0.9922x - 14.302, R2 = 0.9989). This was achieved in 24 seconds of acquisition time for the cine TrueFISP sequence as opposed to 120 seconds for the STIR sequence. Since the first sample of recovery of longitudinal magnetization in our sequence occurred at 80 msec, we were unable to quantify the T1s of those bottles known to have lower T1 values. Conclusion: T1 quantification using an inversion recovery cine TrueFISP sequence is as accurate as using an inversion recovery STIR sequence and is potentially useful for T1 measurements in the torso, since acquisitions can be performed in a single breath-hold.     (V. S. L. : Berlex Laboratories, Speaker (Self)) Questions about this event email: ajhuang@post.harvard.edu

Huang MD, A, Accurate T1 Quantification Using a Breath-hold Inversion Recovery TrueFISP Sequence.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3108747.html