Using cardiac phase to order reconstruction [CAPTOR]: A method to improve diastolic images

Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1061, USA.
Journal of Magnetic Resonance Imaging (Impact Factor: 2.79). 09/1997; 7(5):794-8. DOI: 10.1002/jmri.1880070505
Source: PubMed

ABSTRACT A method is proposed to reconstruct multiphase images that accurately depicts the entire cardiac cycle. A segmented, gradient-recalled-echo sequence (FASTCARD) was modified to acquire data continuously. Images were reconstructed retrospectively by selecting views from each heartbeat based on cardiac phase rather than the time elapsed from the QRS complex. Cardiac phase was calculated using a model that compensates for beat-to-beat heart rate changes. Images collected using cardiac phase to order reconstruction (CAPTOR) depict the entire cardiac cycle and lack the temporal gap that is characteristic of prospectively reconstructed sequences. Time-volume curves of the left ventricle capture the contribution of atrial contraction to end-diastolic volume (EDV). Transmitral phase-contrast flow measurements show a second peak inflow (alpha wave) that is absent in the standard sequence. Because atrial contraction contributes to ventricular EDV, images using CAPTOR potentially may provide a more reliable measure of EDV, stroke volume, and ejection fraction than standard techniques.

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    ABSTRACT: PurposeTo develop a cardiac and respiratory self-gated four-dimensional (4D) coronary MRA technique for simultaneous cardiac anatomy and function visualization. MethodsA contrast-enhanced, ungated spoiled gradient echo sequence with self-gating (SG) and 3DPR trajectory was used for image acquisition. Data were retrospectively binned into different cardiac and respiratory phases based on information extracted from SG projections using principal component analysis. Each cardiac phase was reconstructed using a respiratory motion-corrected self-calibrating SENSE framework, and those belong to the quiescent period were retrospectively combined for coronary visualization. Healthy volunteer studies were conducted to evaluate the efficacy of the SG method, the accuracy of the left ventricle (LV) function parameters and the quality of coronary artery visualization. ResultsSG performed reliably for all subjects including one with poor electrocardiogram (ECG). The LV function parameters showed excellent agreement with those from a conventional cine protocol. For coronary imaging, the proposed method yielded comparable apparent signal to noise ratio and coronary sharpness and lower apparent contrast to noise ratio on three subjects compared with an ECG and navigator-gated Cartesian protocol and an ECG-gated, respiratory motion-corrected 3DPR protocol. ConclusionA fully self-gated 4D whole-heart imaging technique was developed, potentially allowing cardiac anatomy and function assessment from a single measurement. Magn Reson Med 72:1208-1217, 2014. (c) 2014 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 11/2014; 72(5). DOI:10.1002/mrm.25450 · 3.40 Impact Factor
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