Advances in MRI Techniques for Quantitative Imaging: A Review

1. ISMRM2012 Review Jun 4, 2012 Jason Su

2. Outline • Parametric Mapping • Kumar et al. A Bayesian Algorithm Using Spatial Priors for Multi-Exponential T2 Relaxometry from Multi-Echo Spin Echo MRI. [0360] • Ott et al. Phase sensitive PC-bSSFP: simultaneous quantification of T1, T2 and spin density M0. [2387] • Rudrapatna et al. Robust estimation of T1 and T2 parameters from complex datasets. [3418] • Image Reconstruction and Acceleration Methods • Kayvanrad et al. T1 Map Reconstruction from Under-sampled KSpace Data using a Similarity Constraint. [0015] • Weavers et al. Optimal Apportionment of Acceleration in 2D SENSE. [2224] • Myelin Sensitive Sequences • Bluestein et al. Can T1-Differentiation in a Magnetization Prepared Turbo Field Echo Sequence at 7T Predict "Persistent Black Hole” White Matter Lesions in Multiple Sclerosis? [3115]

3. Parametric Mapping

4. A Bayesian Algorithm Using Spatial Priors for Multi-Exponential T2 Relaxometry from Multi-Echo Spin Echo MRI [0360] • Dushyant Kumar et al. University of Hamburg • Goal is to improve noisiness of MWF maps in qT2 • The first term is the data fidelity term • The second term is the conventional temporal regularization term which penalizes large values in inferred T2 distributions • The third term imposes spatial constraints: first difference smoothness • Resulting maps are reminiscent of mcDESPOT MWF and values are similar • However vanilla qT2 MWF values seem overestimated

5. A Bayesian Algorithm Using Spatial Priors for Multi-Exponential T2 Relaxometry from Multi-Echo Spin Echo MRI [0360]

6. Phase sensitive PC-bSSFP: simultaneous quantification of T1, T2 and spin density M0 [2387] • Martin Ott et al. Magnetic Resonance Bavaria e.V, Würzburg, Bayern, Germany • Goal is a new mapping sequence using phase cycled SSFP at two angles, don’t need a T1 map like DESPOT2 • Solution is approximately to fit an ellipse to the data • Still need to compare it against reference techniques

7. Phase sensitive PC-bSSFP: simultaneous quantification of T1, T2 and spin density M0 [2387]

8. Image Reconstruction and Acceleration Methods

9. Optimal Apportionment of Acceleration in 2D SENSE. [2224] • Weaver et al. Mayo Clinic, Rochester, MN • Goal is to optimize the selection of Ry and Rz for a SENSE acquisition given coil sensitivities • Choose Ry and Rz that minimizes the cost: maximum g-factor * scan time • Simple, effective abstract, shouldn’t we have been doing this all along?

10. Optimal Apportionment of Acceleration in 2D SENSE. [2224]

11. Myelin Sensitive Sequences

12. Can T1-Differentiation in a Magnetization Prepared Turbo Field Echo Sequence at 7T Predict "Persistent Black Hole” White Matter Lesions in Multiple Sclerosis? [3115] • Bluestein et al. The Ohio State University, Columbus, Ohio • Goal was to develop a better sequence parameters for a T2w scan that better shows different types of lesions • Simulated behavior of some lesion types with multicomponent signals and then chose parameters • Compared against: • FLAIR (TR = 11000 ms, TI = 2800 ms, TE = 125 ms, TSE factor = 31) • WHAT (TS/TI = 4550/500 ms • “That simulation showed that setting TS = 4500 ms and TI ranging from 880-980 ms, results in images with the long T1 WMLs brighter and short T1 WMLs darker than surrounding NAWM.”

13. Can T1-Differentiation in a Magnetization Prepared Turbo Field Echo Sequence at 7T Predict "Persistent Black Hole” White Matter Lesions in Multiple Sclerosis? [3115]