Lung Imaging in the Mouse with SWIFT Curt Corum, Djaudat Idiyatullin, Steen Moeller, Ryan Chamberlain, Deepali Sachdev, and Mike Garwood Center for Magnetic Resonance Research and Masonic Cancer Center, School of Medicine University of Minnesota, Minneapolis, Minnesota, USA #204

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 2 Declaration of Conflict of Interest or Relationship Speaker Name: Curt Corum I have the following conflict(s) of interest to disclose with regard to the subject matter of this presentation: Dr. Corum is entitled to sales royalty from Steady State Imaging, which is developing products related to the research described in this presentation.

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 3 Motivation Lung and especially lung parenchyma is difficult to image with MRI Low proton density, susceptibility, T 2, T 2 *, cardiac and respiratory motion all contribute At higher fields intrinsic (air to tissue and pathology) and extrinsic (contrast injection) suseptibility effects become stronger With T 2 * sensitive sequences these cause signal dropout and phase effects due to the local field changes

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 4 Lots of interest and great work... UTE approach Human and Animal Bergin, Noll et al Shattuck, Gewalt et al GRE approach Human and Animal Much great work... FID (BLAST, RUFIS) Animal Imaging Kuethe et al. and others...

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 5 AQ G ro RF UTE excite → ramp BLAST and RUFIS ramp → excite SWIFTGRE AQ G ro RF HSn AQ G ro RF Sequences for capturing short T2 signals

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 6 T 2 * of Parenchyma Mouse Lung GRE TE = 2ms Respiratory gated Clip level adjustment

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 7 SWIFT Sequence SWeep Imaging with Fourier Transform Acquisition occurs in the gaps of a frequency swept (usually HSn) pulse Excitation and Acquisition nearly simultaneous “dead time” ~2 µs No time for slice selection or phase encoding, is most naturally a readout only, interleaved preparations are possible Aquired data are FIDs (after correlation with the RF pulse shape) Operates in 2d projection mode or 3d image mode with radial FID sampling scheme and gridding reconstruction Most similar to BLAST, RUFIS, etc. in concept

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 8 SWIFT Sequence Idiyatullin, D.; Corum, C.; Park, J. Y. & Garwood, M., Fast and quiet MRI using a swept radiofrequency., J Magn Reson, 2006, 181,

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 9 Mouse Model of Lung Cancer 7-9 week old athymic mice Lung seeking metastatic variant of MDA-MB-231 breast cancer cells injected into the tail vein. D. Sachdev Isoflurane O 2 N 2 O anesthesia N=4 Healthy Animals and N=2 Tumor animals so far...

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 10 MRI parameters SWIFT TR 2.2 ms dead time 2 µs 125 kHz acquisition bandwidth 3072*16*2 = 96,304 unique FID views 256 complex points per view Prospective respiratory trigger and gating, % duty views per trigger (typically 128) Reconstruction to 256^3 3D image ~0.12 mm nominal resolution 8-9 min (x4) for min total imaging time per animal

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 11 Healthy Mouse Respiratory pillow gated, 125kHz SWIFT 9.4 T Varian animal system Combination of 4x 8 min scans (32 min) Quadrature surface coil on back Animal is prone, ~3x3x4 cm fov Intensity flattening appliedReformatted to bronchial V Native intensity

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 12 Tumor Mouse Same parameters Left lung has collapsed Intensity flattening appliedReformatted to bronchial V Native intensity

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 13 Tumor Montage

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 14 Excised Lung D. Sachdev

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 15 Discussion Preserves signal Lung Parenchyma and signal next to susceptibility boudaries (bronchii to parenchyma, vessels to parenchyma, tumor margin to parenchyma, etc...) Avoidance of gradient ramp sampling required for UTE sequences Avoidance of acuostic noise and eddy currents Low peak RF power compared to BLAST or RUFIS (radial FID aquisition sequences), T 1 weighting obtainable Scalable to Human Imaging

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 16 Future Work Histological and Pathological verification normal tissue, tumors, inflammation Scalable to human imaging (no peak power or gradient performance limitations) Contrast and DCE

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 17 Support NIH BTRR 5P41RR CMRR Center Grant, Core 3, PI Mike Garwood Masonic Cancer Center (startup), PI Deepali Sachdev 1R21CA , PI Curt Corum IMPROVED BREAST DCE MRI WITH SWIFT MN MED FDN/ , PI Curt Corum MRI Utilizing SWIFT to Detect Breast Calcifications, Minnesota Medical Foundation

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 18 Upcoming SWIFT presentations Theoretical Sensitivities of SWIFT and the Ideal Sequence (Delta Pulse-Acquire) for Ultra-Short T2 Tuesday 4 May, 13: :30 #2975 Detection of Short T2 Component in Brain by SWIFT Tuesday 4 May, 13: :30 #2980 In Vivo SWIFT Imaging of SPIO Labeled Stem Cells Grafted in the Heart Tuesday 4 May, 14: :00 #3747, Computer 40 Measurement of T1 Relaxation Time in Articular Cartilage Using SWIFT Wednesday 5 May, 13: :30 #841 Dipole Matched Filter with SWIFT Wednesday 5 May, 14: :00 #5113, Computer 126 SWIFT Versus X-Ray In Dental Imaging Thursday 6 May,12: :30 Room A5 #543

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 19 Bonus: Detailed SWIFT Timing

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 20 Bonus: Dipole Matched Filter Bo Unfiltered Magnitude ImageRe Image After dipole matched filter F in k-space Mag Image After dipole matched filter F in k-space 62kHz SWIFT at 4 T 2 o'clock position has MRI compatible catheter tip E-Poster #5113 Thurs

5/4/2010ISMRM 2010 #204 Lung Imaging in the Mouse with SWIFT 21 Bonus: Teeth With Don Nixdorf, DDS, Hari Prasad, et al. See talk #543 Thurs 05/06, 12:18 PM, room A5