Traditional Posters: Body Imaging

Grzegorz Bauman^1,2, Michael Deimling³, Michael Puderbach⁴, Lothar Rudi Schad<sup>2

1</sup>Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; ²Computer Assisted Clinical Medicine, University of Heidelberg, Mannheim, Germany; ³Siemens Healthcare, Erlangen, Germany; ⁴Department of Radiology, German Cancer Research Center, Heidelberg, Germany

In lung MRI, due to the fast signal dephasing, respiratory motion and cardiac pulsation, very fast imaging sequences using short repetition times or the application of triggering techniques are required. The aim of this work was to numerically simulate and optimize the Steady-State Free Precession (SSFP) imaging scheme for dynamic studies on a 1.5 T whole-body MR-scanner. Fast imaging with the SSFP sequence using a combination of the central k-space sampling, parallel imaging, high bandwidth and minimal inter-echo sampling allowed to improve the visualization of the pulmonary tissue sufficiently for functional lung MRI.

2509. High Resolution T2 Weighted Lung Imaging with a Radial Turbo Spin-Echo Sequence

Michael Völker¹, Philipp Ehses¹, Martin Blaimer², Felix Breuer², Peter Michael Jakob<sup>1,2

1</sup>Department of Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany; ²Research Center for Magnetic Resonance Bavaria (MRB), Würzburg, Germany

A segmented radial Turbo Spin-Echo (rTSE) sequence was investigated towards its feasibility for high resolution lung imaging under free breathing conditions. No triggering techniques were involved to define the limits of the sequence itself. Unlike ultrafast singleshot techniques such as HASTE resolution is not intrinsically limited by the T2 signal decay while motion, especially of the beating heart, poses only a small problem in comparison with conventional Cartesian TSE. In addition, arbitrary T2 contrasts may be generated by postprocessing a single dataset allowing for the calculation of quantitative T2 maps.

2510. Proton MRI of Human Lung Using 2D Radial Acquisition at 1.5 T and 3.0 T

Jascha Zapp¹, Simon Konstandin¹, Lothar R. Schad<sup>1

1</sup>Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany

MRI of the lung is challenging because of low proton density, respiratory and cardiac motion and susceptibility effects at air-tissue interfaces. A healthy volunteer was examined using a 2D radial gradient echo technique (resolution: 0.8mm x 0.8mm x 5.0mm) with conventional (full) RF pulses (TE=0.77ms) and half RF pulses (TE=0.02ms) at 1.5T and 3.0T. Average SNR in lung parenchyma resulted in an increase of 56% at 3.0T compared to 1.5T with TE=0.02ms. The result shows that SNR in proton MRI of human lung at 3.0T is superior to 1.5T when using a 2D radial sequence with ultrashort echo time.

2511. Feasibility of Using Linear Combination SSFP for Lung MRI at 3 T

Atiyah Yahya^1,2, Keith Wachowicz^1,2, B. Gino Fallone<sup>1,2

1</sup>Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada; ²Department of Oncology, University of Alberta, Edmonton, Alberta, Canada

MRI of the lungs is challenging because of the low proton density and because of the large number of air-tissue interfaces which create susceptibility gradients. Lung MRI has shown to be feasible at 3 T using the HASTE sequence with parallel imaging. In this work we examine the feasibility of applying Linear Combination SSFP (LCSSFP) for lung MRI at 3 T. Experiments were conducted on a normal volunteer and lung images were acquired with both HASTE and LCSSFP. The images acquired with LCSSFP were clearer and did not suffer from blurring compared to the HASTE images.

2512. MRI as a Non-X Ray Based Imaging Alternative to Study Experimental Lung Fibrosis Induced by Bleomycin in Rats