We continuously seek to improve imaging capabilities of the abdomen by developing new methods that reduce scan time, overcome difficulties introduced by motion or metal implants, and obtain new information useful in the clinical setting.
Metal implants severely limit conventional MR imaging due to the metal-induced susceptibility changes in the B0 field, which create a wide distribution of proton resonant frequencies in adjacent tissue. Ultimately, any MR acquisition that uses frequency-encoding is fundamentally limited in its ability to eliminate distortion artifacts related to metal. We develop and test a spectrally resolved fully phase-encoded (SR-FPE) 3D FSE technique for distortion-free imaging near metal. We also investigate acceleration methods, including parallel imaging acceleration in three directions, to achieve scan time reductions necessary for clinical implementation.
In many applications long scan times are required to acquire sufficient images, requiring patients to perform multiple breath holds to limit breath-motion induced artifacts. In some populations these scans prove challenging and limit the image quality. Improved acquisition sequences can significantly reduce scan times, but many applications still require significant acquisition times. Strategies such as gating of the imaging to the breathing of the patient reduce motion artifacts and allow patients to freely breathe during the scans.
- Artz N, Wiens C, Smith M, Hernando D, Samsonov A and Reeder S. Accelerating fully phase-encoded MRI near metal using multiband radiofrequency excitation. Magnetic Resonance in Medicine. 2017 mar;77(3):1223-1230. DOI PMID
- Wiens C, Artz N, Jang H, McMillan A and Reeder S. Externally calibrated parallel imaging for 3D multispectral imaging near metallic implants using broadband ultrashort echo time imaging. Magnetic Resonance in Medicine. 2017 jul;77(6):2303-2309. DOI PMID
- Wiens C, Artz N, Jang H, McMillan A, Koch K and Reeder S. Fully phase-encoded MRI near metallic implants using ultrashort echo times and broadband excitation. Magnetic Resonance in Medicine. 2018 aug;79(4):2156-2163. DOI PMID
- Motosugi U, Hernando D, Bannas P, Holmes JH, Wang K, Shimakawa A, Iwadate Y, Taviani V, Rehm JL and Reeder SB. Quantification of liver fat with respiratory-gated quantitative chemical shift encoded MRI. Journal of Magnetic Resonance Imaging. 2015;42(5):1241-1248. DOI PMID
- Artz NS, Hernando D, Taviani V, Samsonov A, Brittain JH and Reeder SB. Spectrally resolved fully phase-encoded three-dimensional fast spin-echo imaging. Magnetic Resonance in Medicine. 2014;71(2):681-690. DOI PMID