The long term objective of this work is to improve methods to quickly and accurately diagnose human disease using MRI and provide resources that can be used for image guided therapy in the future. Balanced steady state free precession (bSSFP) is a leading rapid MR imaging sequence with high signal-to-noise efficiency. However, the contrast is a mixture of T1 and T2 weighting and although the signal from flowing blood is hyperintense, the sequence is not used routinely for angiography since other tissues are not suppressed. The objective of this work is to modify the magnetization preparation and readout properties of the bSSFP sequence in order to extend the powerful bSSFP framework to important new applications.
The first aim i s to develop and improve methods for removing T1 and isolating T2 contrast in bSSFP imaging. T2 contrast has proven to be an indispensable tool in the differentiation of many different diseases via MRI (e.g. myocardial edema associated with cardiomyopathies). Methods to simultaneously improve spatial resolution and maximize T2 contrast while minimizing scan time, RF energy deposition and off-resonance banding will be developed.
The second aim i s to develop improved methods of attenuating the signal from flowing blood in bSSFP imaging. This is important for taking accurate measurement of vessel sizes, visualizing diseases involving the vessel wall (e.g. atherosclerosis) and to remove flow artifacts. New methods of providing black blood images with bSSFP contrast in stationary tissues without significantly increasing the repetition time will be investigated.
The third aim i s to develop exogenous contrast agent-free flow angiography with improved temporal resolution. In many clinical applications it is important to selectively visualize the blood vessels (e.g. peripheral artery disease). The widely used method of injecting a T1 shortening contrast agent has become extremely problematic in patient populations with impaired renal function due to the recent revelation of the associated risk of the progressive and life-threatening disease Nephrogenic Systemic Fibrosis (NSF). For each of the three aims extensive computer simulations, testing in stationary and flow phantoms, animals, asymptomatic human volunteers and finally human patients will be performed to develop the new MR imaging techniques and to determine their clinical utility.
| Derakhshan, Jamal J; Nour, Sherif G; Sunshine, Jeffrey L et al. (2012) Resolution enhanced T1-insensitive steady-state imaging. Magn Reson Med 68:421-9 |
| Gudino, N; Heilman, J A; Derakhshan, J J et al. (2011) Control of intravascular catheters using an array of active steering coils. Med Phys 38:4215-24 |
| Derakhshan, Jamal J; Griswold, Mark A; Nour, Sherif G et al. (2010) Characterization and reduction of saturation banding in multiplanar coherent and incoherent steady-state imaging. Magn Reson Med 63:1415-21 |
| Derakhshan, Jamal J; Griswold, Mark A; Sunshine, Jeffrey L et al. (2009) Halting the effects of flow enhancement with effective intermittent zeugmatographic encoding (HEFEWEIZEN) in SSFP. J Magn Reson Imaging 29:1163-74 |
