Ian Marshall, Maurits A Jansen, Yuehui Tao, Gavin D Merrifield, Gillian A Gray University of Edinburgh Accelerated mouse cardiac imaging using threefold undersampling and kt-BLAST reconstruction 3847 Computer 35

Introduction Mouse kt-BLAST cardiac imaging3847 Why acceleration? - shorter scan times, reduced costs, - improved patient compliance - reduced animal burden Parallel imaging now widely used clinically (some) kt-undersampling for human cardiac scanning Limited translation of techniques to rodent imaging - would improve animal welfare (3Rs)

Study design 6 healthy + 2 MI adult mice Cardiac MRI scans in short-axis plane Standard CINE sequence 3-fold accelerated ktBLAST sequence + training data Comparison of image quality and cardiac indices EDV, ESV, EF, EDM, ESM Mouse kt-BLAST cardiac imaging3847

Scanning details 7T scanner (Agilent Technologies) 39 mm quad coil Respiratory gating and cardiac triggering CINE Gradient Echo sequence - (12 frames, 192×192, FOV 30 mm, 3 Averages) kt-BLAST sequence (Tsao MRM 2003) - 3× undersampling (linear grid) - 16 central training rows Mouse kt-BLAST cardiac imaging3847

Image analysis One analyst, blinded to type of images Subjective quality (scale 1-5) Endo- and epicardial borders drawn manually Cardiological indices derived Mouse kt-BLAST cardiac imaging3847

Images fully sampled 3× undersampled Mouse kt-BLAST cardiac imaging3847

“Ratios” Mouse kt-BLAST cardiac imaging3847 =MI

Bland-Altman plot Mouse kt-BLAST cardiac imaging3847 EDV MI

Results summary Cardiological indices (σ) wrt fully sampled images “Ratios” Bland-Altman bias EDV0.94(0.07)-5 (8) μL ESV1.06(0.14) 2 (6) μL EF0.93(0.08) -5 (5) % EDM1.11(0.10) 13 (12) mg ESM1.01(0.06) 1 (8) mg Image quality: 4.3±1.2 (full) versus 3.8±1.4 (ktBLAST) Mouse kt-BLAST cardiac imaging3847

Discussion kt-BLAST images have similar “quality” “Ratios” biased up to 11% (for EDM) - corresponding Bland-Altman bias 13 mg Observer variability 3-10% (Heijman JMRI 2008) MI mice (large hearts and small EF) Overall acceleration 2.4× Compare with Compressed Sensing (Wech JMRI 2011) Mouse kt-BLAST cardiac imaging3847

Conclusion Mouse kt-BLAST cardiac imaging3847 Accelerated cardiac imaging of mice is feasible Threefold acceleration gives acceptable results This enables - increased throughput - improved animal welfare

Acknowledgements Peter Hoskins Tom Anderson Steven Fortune Mike Davies Gabriel Rilling Ross Lennen Agnieszka Kozak Mouse kt-BLAST cardiac imaging3847