Spin-echo SS-PARSE: a PARSE MRI method to estimate frequency, R2 and R2′ in a single shot

Abstract

Spin echo signals allow separate measurements of irreversible and reversible relaxation rates in MRI. A spin echo version of Single-shot Parameter Assessment by Retrieval from Signal Encoding (SE-SS-PARSE) method has been developed to quantitatively and accurately map transverse magnetization magnitude, frequency, irreversible and reversible relaxation rates in a single shot. These image parameters can be applied to fMRI research as well as a number of neuroimaging applications. Following a description of the signal model, this paper demonstrates the performance of SE-SS-PARSE in simulations with different noise levels and in phantom experiments. By solving an inverse problem, the estimated irreversible and reversible relaxation rates in SE-SS-PARSE are highly correlated with the reference relaxation rates from a standard technique (correlation coefficients r1=0.9636 for reversible relaxation rate, r2= 0.9788 for irreversible relaxation rate). The rapid SE-SS-PARSE technique has the potential to monitor transient changes in R2 and R2’ while minimizing motion artifacts, and also is free of geometric and ghosting errors. It is expected that this fast scan technique will find applications in both scientific research and clinical diagnosis.

Snapshot MR Technique to Measure OEF Using Rapid Frequency Mapping

“…While it is beyond the scope of this implementation, it is possible to use spin-echo PARSE 39 to use R 2 ' information as a validation technique. The PARSE technique that is implemented uses a conjugate gradient-based least squares minimization to estimate multiple encoded parameters from the FID signal.…”

Simultaneous T2 and mapping of multiple sclerosis lesions with radial RARE‐EPI

“…Given the characteristic MRI features of MS lesions, it is conceptually appealing to pursue techniques that support simultaneous generation of quantitative maps of multiple MR contrasts. 32,[49][50][51][52][53][54][55][56][57][58][59][60] Dual contrast techniques offer substantial scan time reduction, eliminate the risk for slice misregistration, improve the immunity to bulk motion, and boost clinical use. The current study presents a modular rapid acquisition with relaxation enhancement (RARE)-EPI hybrid, which is a combined acquisition technique variant.…”