MR Multitasking‐based multi‐dimensional assessment of cardiovascular system (MT‐MACS) with extended spatial coverage and water‐fat separation

Figures

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  FIGURE 1. Pulse sequence diagram for the MT‐MACS technique and corresponding k‐space sampling pattern. A, T2‐prepared inversion recovery (T2IR) magnetization preparations are applied at constant intervals followed by dual‐echo stack‐of‐stars FLASH readouts. Following each T2IR preparation module, RF pulse flip angles are 3° for the first 300 segments, and 1° for the next 200 segments. Auxiliary data are interleaved with imaging data every six segments. B, Simplified illustration of k‐space sampling strategy. The auxiliary data are collected at the 0° radial spoke of the center partition. For the imaging data, randomized partition‐encoding reordering following a variable‐density Gaussian distribution with the highest density at the center partition adopted in this sequence.

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  FIGURE 2. Example MT‐MACS images of the ventricular chambers (coronal view and short axis [SAX] view) and thoracic aorta at the mid‐diastolic end‐expiration phase generated from a 28‐y‐old female subject (Subject 1) and a 65‐y‐old male subject (Subject 2). Water‐only images with multiple contrast weightings, including BB, DB, and GB, and fat‐only images are displayed for each slice orientation.

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  FIGURE 3. Quantification of myocardial wall thickness of the LA/ LV/ RA/ RV. A, Graphic illustration of measuring the myocardial wall thickness of the LA/LV/RA/RV in a 40‐y‐old male subject. Myocardial wall thickness of each cardiac chamber was measured at the same location on the DB images of MT‐MACS at the mid‐diastolic end‐expiratory phase and corresponding 2D T2‐weighted turbo spin‐echo images with matched location and slice thickness. B, Bland–Altman plots and ICCs comparing measurement agreements between these two imaging techniques.

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  FIGURE 4. Quantification of LVEF. A, Graphic illustration of measuring LVEF in a 39‐y‐old male subject. The blood‐myocardium boundary was manually contoured in each slice of the MT‐MACS BB images and corresponding 2D cine balanced SSFP images with matched location and slice thickness for both the end‐diastolic and end‐systolic phases. B, Linear regression, ICCs, and Bland–Altman analyses comparing the measurement results acquired by these two imaging techniques.